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Sample records for artificial nanostructures fabrication

  1. Plasmonic nanostructures: artificial molecules.

    PubMed

    Wang, Hui; Brandl, Daniel W; Nordlander, Peter; Halas, Naomi J

    2007-01-01

    This Account describes a new paradigm for the relationship between the geometry of metallic nanostructures and their optical properties. While the interaction of light with metallic nanoparticles is determined by their collective electronic or plasmon response, a compelling analogy exists between plasmon resonances of metallic nanoparticles and wave functions of simple atoms and molecules. Based on this insight, an entire family of plasmonic nanostructures, artificial molecules, has been developed whose optical properties can be understood within this picture: nanoparticles (nanoshells, nanoeggs, nanomatryushkas, nanorice), multi-nanoparticle assemblies (dimers, trimers, quadrumers), and a nanoparticle-over-metallic film, an electromagnetic analog of the spinless Anderson model. PMID:17226945

  2. Atomically Traceable Nanostructure Fabrication.

    PubMed

    Ballard, Josh B; Dick, Don D; McDonnell, Stephen J; Bischof, Maia; Fu, Joseph; Owen, James H G; Owen, William R; Alexander, Justin D; Jaeger, David L; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J; Wallace, Robert M; Reidy, Richard; Silver, Richard M; Randall, John N; Von Ehr, James

    2015-01-01

    Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure. PMID:26274555

  3. Nanoscale topographical replication of graphene architecture by artificial DNA nanostructures

    NASA Astrophysics Data System (ADS)

    Moon, Y.; Shin, J.; Seo, S.; Park, J.; Dugasani, S. R.; Woo, S. H.; Park, T.; Park, S. H.; Ahn, J. R.

    2014-06-01

    Despite many studies on how geometry can be used to control the electronic properties of graphene, certain limitations to fabrication of designed graphene nanostructures exist. Here, we demonstrate controlled topographical replication of graphene by artificial deoxyribonucleic acid (DNA) nanostructures. Owing to the high degree of geometrical freedom of DNA nanostructures, we controlled the nanoscale topography of graphene. The topography of graphene replicated from DNA nanostructures showed enhanced thermal stability and revealed an interesting negative temperature coefficient of sheet resistivity when underlying DNA nanostructures were denatured at high temperatures.

  4. Nanoscale topographical replication of graphene architecture by artificial DNA nanostructures

    SciTech Connect

    Moon, Y.; Seo, S.; Park, J.; Park, T.; Ahn, J. R.; Shin, J.; Dugasani, S. R.; Woo, S. H.; Park, S. H.

    2014-06-09

    Despite many studies on how geometry can be used to control the electronic properties of graphene, certain limitations to fabrication of designed graphene nanostructures exist. Here, we demonstrate controlled topographical replication of graphene by artificial deoxyribonucleic acid (DNA) nanostructures. Owing to the high degree of geometrical freedom of DNA nanostructures, we controlled the nanoscale topography of graphene. The topography of graphene replicated from DNA nanostructures showed enhanced thermal stability and revealed an interesting negative temperature coefficient of sheet resistivity when underlying DNA nanostructures were denatured at high temperatures.

  5. Chemically enabled nanostructure fabrication

    NASA Astrophysics Data System (ADS)

    Huo, Fengwei

    The first part of the dissertation explored ways of chemically synthesizing new nanoparticles and biologically guided assembly of nanoparticle building blocks. Chapter two focuses on synthesizing three-layer composite magnetic nanoparticles with a gold shell which can be easily functionalized with other biomolecules. The three-layer magnetic nanoparticles, when functionalized with oligonucleotides, exhibit the surface chemistry, optical properties, and cooperative DNA binding properties of gold nanoparticle probes, while maintaining the magnetic properties of the Fe3O4 inner shell. Chapter three describes a new method for synthesizing nanoparticles asymmetrically functionalized with oligonucleotides and the use of these novel building blocks to create satellite structures. This synthetic capability allows one to introduce valency into such structures and then use that valency to direct particle assembly events. The second part of the thesis explored approaches of nanostructure fabrication on substrates. Chapter four focuses on the development of a new scanning probe contact printing method, polymer pen lithography (PPL), which combines the advantages of muCp and DPN to achieve high-throughput, flexible molecular printing. PPL uses a soft elastomeric tip array, rather than tips mounted on individual cantilevers, to deliver inks to a surface in a "direct write" manner. Arrays with as many as ˜11 million pyramid-shaped pens can be brought into contact with substrates and readily leveled optically in order to insure uniform pattern development. Chapter five describes gel pen lithography, which uses a gel to fabricate pen array. Gel pen lithography is a low-cost, high-throughput nanolithography method especially useful for biomaterials patterning and aqueous solution patterning which makes it a supplement to DPN and PPL. Chapter 6 shows a novel form of optical nanolithography, Beam Pen Lithography (BPL), which uses an array of NSOM pens to do nanoscale optical

  6. Nanostructured artificial nacre

    NASA Astrophysics Data System (ADS)

    Tang, Zhiyong; Kotov, Nicholas A.; Magonov, Sergei; Ozturk, Birol

    2003-06-01

    Finding a synthetic pathway to artificial analogs of nacre and bones represents a fundamental milestone in the development of composite materials. The ordered brick-and-mortar arrangement of organic and inorganic layers is believed to be the most essential strength- and toughness-determining structural feature of nacre. It has also been found that the ionic crosslinking of tightly folded macromolecules is equally important. Here, we demonstrate that both structural features can be reproduced by sequential deposition of polyelectrolytes and clays. This simple process results in a nanoscale version of nacre with alternating organic and inorganic layers. The macromolecular folding effect reveals itself in the unique saw-tooth pattern of differential stretching curves attributed to the gradual breakage of ionic crosslinks in polyelectrolyte chains. The tensile strength of the prepared multilayers approached that of nacre, whereas their ultimate Young modulus was similar to that of lamellar bones. Structural and functional resemblance makes clay- polyelectrolyte multilayers a close replica of natural biocomposites. Their nanoscale nature enables elucidation of molecular processes occurring under stress.

  7. Fabrication of zein nanostructure

    NASA Astrophysics Data System (ADS)

    Luecha, Jarupat

    resins. The soft lithography technique was mainly used to fabricate micro and nanostructures on zein films. Zein material well-replicated small structures with the smallest size at sub micrometer scale that resulted in interesting photonic properties. The bonding method was also developed for assembling portable zein microfluidic devices with small shape distortion. Zein-zein and zein-glass microfluidic devices demonstrated sufficient strength to facilitate fluid flow in a complex microfluidic design with no leakage. Aside from the fabrication technique development, several potential applications of this environmentally friendly microfluidic device were investigated. The concentration gradient manipulation of Rhodamine B solution in zein-glass microfluidic devices was demonstrated. The diffusion of small molecules such as fluorescent dye into the wall of the zein microfluidic channels was observed. However, with this formulation, zein microfluidic devices were not suitable for cell culture applications. This pioneer study covered a wide spectrum of the implementation of the two nanotechnology approaches to advance zein biomaterial which provided proof of fundamental concepts as well as presenting some limitations. The findings in this study can lead to several innovative research opportunities of advanced zein biomaterials with broad applications. The information from the study of zein nanocomposite structure allows the packaging industry to develop the low cost biodegradable materials with physical property improvement. The information from the study of the zein microfluidic devices allows agro-industry to develop the nanotechnology-enabled microfluidic sensors fabricated entirely from biodegradable polymer for on-site disease or contaminant detection in the fields of food and agriculture.

  8. Superconducting vortex pinning with artificial magnetic nanostructures.

    SciTech Connect

    Velez, M.; Martin, J. I.; Villegas, J. E.; Hoffmann, A.; Gonzalez, E. M.; Vicent, J. L.; Schuller, I. K.; Univ. de Oviedo-CINN; Unite Mixte de Physique CNRS Univ. Paris-Sud; Univ.Complutense de Madrid; Univ. California at San Diego

    2008-11-01

    This review is dedicated to summarizing the recent research on vortex dynamics and pinning effects in superconducting films with artificial magnetic structures. The fabrication of hybrid superconducting/magnetic systems is presented together with the wide variety of properties that arise from the interaction between the superconducting vortex lattice and the artificial magnetic nanostructures. Specifically, we review the role that the most important parameters in the vortex dynamics of films with regular array of dots play. In particular, we discuss the phenomena that appear when the symmetry of a regular dot array is distorted from regularity towards complete disorder including rectangular, asymmetric, and aperiodic arrays. The interesting phenomena that appear include vortex-lattice reconfigurations, anisotropic dynamics, channeling, and guided motion as well as ratchet effects. The different regimes are summarized in a phase diagram indicating the transitions that take place as the characteristic distances of the array are modified respect to the superconducting coherence length. Future directions are sketched out indicating the vast open area of research in this field.

  9. Method of fabrication of anchored nanostructure materials

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2013-11-26

    Methods for fabricating anchored nanostructure materials are described. The methods include heating a nano-catalyst under a protective atmosphere to a temperature ranging from about 450.degree. C. to about 1500.degree. C. and contacting the heated nano-catalysts with an organic vapor to affix carbon nanostructures to the nano-catalysts and form the anchored nanostructure material.

  10. Anchored nanostructure materials and method of fabrication

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2012-11-27

    Anchored nanostructure materials and methods for their fabrication are described. The anchored nanostructure materials may utilize nano-catalysts that include powder-based or solid-based support materials. The support material may comprise metal, such as NiAl, ceramic, a cermet, or silicon or other metalloid. Typically, nanoparticles are disposed adjacent a surface of the support material. Nanostructures may be formed as anchored to nanoparticles that are adjacent the surface of the support material by heating the nano-catalysts and then exposing the nano-catalysts to an organic vapor. The nanostructures are typically single wall or multi-wall carbon nanotubes.

  11. Surface plasmon polaritons in artificial metallic nanostructures

    NASA Astrophysics Data System (ADS)

    Briscoe, Jayson Lawrence

    Surface plasmon polaritons have been the focus of intense research due to their many unique properties such as high electromagnetic field localization, extreme sensitivity to surface conditions, and subwavelength confinement of electromagnetic waves. The area of potential impact is vast and includes promising advancements in photonic circuits, high speed photodetection, hyperspectral imaging, spectroscopy, enhanced solar cells, ultra-small scale lithography, and microscopy. My research has focused on utilizing these properties to design and demonstrate new phenomena and implement real-world applications using artificial metallic nanostructures. Artificial metallic nanostructures employed during my research begin as thin planar gold films which are then lithographically patterned according to previously determined dimensions. The result is a nanopatterned device which can excite surface plasmon polaritons on its surface under specific conditions. Through my research I characterized the optical properties of these devices for further insight into the interesting properties of surface plasmon polaritons. Exploration of these properties led to advancements in biosensing, development of artificial media to enhance and control light-matter interactions at the nanoscale, and hybrid plasmonic cavities. Demonstrations from these advancements include: label-free immunosensing of Plasmodium in a whole blood lysate, low part-per-trillion detection of microcystin-LR, enhanced refractive index sensitivity of novel resonant plasmonic devices, a defect-based plasmonic crystal, spontaneous emission modification of colloidal quantum dots, and coupling of plasmonic and optical Fabry-Perot resonant modes in a hybrid cavity.

  12. Fabrication and characterization of amorphous silica nanostructures

    NASA Astrophysics Data System (ADS)

    Jin, Lei; Wang, Jianbo; Cao, Guangyi; Choy, Wallace C. H.

    2008-06-01

    Large-scale amorphous silica nanostructures, including nanowires, nanotubes and flowerlike nanowire bunches depending on the position, have been fabricated on silicon wafer through a cheap route under the assistance of gold and germanium. Accompanying the observation of blue-green light emission, comprehensive micro-structural characterization reveals that the growth of nanostructures is catalyzed only by gold whereas the final morphology of nanostructures depends on the location to germanium ball. Au 2Si, a compound of gold and silicon, is also disclosed as an intermediate state during the catalysis. Correspondingly, a growth scheme is proposed based on the experimental results and the vapor-liquid-solid mechanism.

  13. Ceramic nanostructures and methods of fabrication

    DOEpatents

    Ripley, Edward B.; Seals, Roland D.; Morrell, Jonathan S.

    2009-11-24

    Structures and methods for the fabrication of ceramic nanostructures. Structures include metal particles, preferably comprising copper, disposed on a ceramic substrate. The structures are heated, preferably in the presence of microwaves, to a temperature that softens the metal particles and preferably forms a pool of molten ceramic under the softened metal particle. A nano-generator is created wherein ceramic material diffuses through the molten particle and forms ceramic nanostructures on a polar site of the metal particle. The nanostructures may comprise silica, alumina, titania, or compounds or mixtures thereof.

  14. Controllable fabrication of copper phthalocyanine nanostructure crystals

    NASA Astrophysics Data System (ADS)

    Liu, Fangmei; Sun, Jia; Xiao, Si; Huang, Wenglong; Tao, Shaohua; Zhang, Yi; Gao, Yongli; Yang, Junliang

    2015-06-01

    Copper phthalocyanine (CuPc) nanostructure crystals, including nanoflower, nanoribbon, and nanowire, were controllably fabricated by temperature gradient physical vapor deposition (TG-PVD) through controlling the growth parameters. In a controllable growth system with carrier gas N2, nanoflower, nanoribbon, and nanowire crystals were formed in a high-temperature zone, medium-temperature zone, and low-temperature zone, respectively. They were proved to be β-phase, coexist of α-phase and β-phase, and α-phase respectively based on x-ray diffraction results. Furthermore, ultralong CuPc nanowires up to several millimeters could be fabricated by TG-PVD without carrier gas, and they were well-aligned to form large-area CuPc nanowire crystal arrays by the Langmuir-Blodgett method. The nanostructure crystals showed unusual optical absorption spectra from the ultraviolet-visible to near-infrared range, which was explained by the diffraction and scattering caused by the wavelength-sized nanostructures. These CuPc nanostructure crystals show potential applications in organic electronic and optoelectronic devices.

  15. Controllable fabrication of copper phthalocyanine nanostructure crystals.

    PubMed

    Liu, Fangmei; Sun, Jia; Xiao, Si; Huang, Wenglong; Tao, Shaohua; Zhang, Yi; Gao, Yongli; Yang, Junliang

    2015-06-01

    Copper phthalocyanine (CuPc) nanostructure crystals, including nanoflower, nanoribbon, and nanowire, were controllably fabricated by temperature gradient physical vapor deposition (TG-PVD) through controlling the growth parameters. In a controllable growth system with carrier gas N2, nanoflower, nanoribbon, and nanowire crystals were formed in a high-temperature zone, medium-temperature zone, and low-temperature zone, respectively. They were proved to be β-phase, coexist of α-phase and β-phase, and α-phase respectively based on x-ray diffraction results. Furthermore, ultralong CuPc nanowires up to several millimeters could be fabricated by TG-PVD without carrier gas, and they were well-aligned to form large-area CuPc nanowire crystal arrays by the Langmuir-Blodgett method. The nanostructure crystals showed unusual optical absorption spectra from the ultraviolet-visible to near-infrared range, which was explained by the diffraction and scattering caused by the wavelength-sized nanostructures. These CuPc nanostructure crystals show potential applications in organic electronic and optoelectronic devices. PMID:25961155

  16. Metal plasmas for the fabrication of nanostructures

    SciTech Connect

    Anders, Andre

    2006-09-21

    A review is provided covering metal plasma production, theenergetic condensation of metal plasmas, and the formation ofnanostructures using such plasmas. Plasma production techniques includepulsed laser ablation, filtered cathodic arcs, and various forms ofionized physical vapor deposition, namely magnetron sputtering withionization of sputtered atoms in radio frequency discharges,self-sputtering, and high power impulse magnetron sputtering. Thediscussion of energetic condensation focuses on the control of kineticenergy by biasing and also includes considerations of the potentialenergy and the processes occurring at subplantation and implantation. Inthe final section on nanostructures, two different approaches arediscussed. In the top-down approach, the primary nanostructures arelithographically produced and metal plasma is used to coat or filltrenches and vias. Additionally, multilayers with nanosize periods(nanolaminates) can be produced. In the bottom-up approach, thermodynamicforces are used to fabricate nanocomposites and nanoporous materials bydecomposition and dealloying.

  17. Fabrication of Hydrophobic Nanostructured Surfaces for Microfluidic Control.

    PubMed

    Morikawa, Kyojiro; Tsukahara, Takehiko

    2016-01-01

    In the field of micro- and nanofluidics, various kinds of novel devices have been developed. For such devices, not only fluidic control but also surface control of micro/nano channels is essential. Recently, fluidic control by hydrophobic nanostructured surfaces have attracted much attention. However, conventional fabrication methods of nanostructures require complicated steps, and integration of the nanostructures into micro/nano channels makes fabrication procedures even more difficult and complicated. In the present study, a simple and easy fabrication method of nanostructures integrated into microchannels was developed. Various sizes of nanostructures were successfully fabricated by changing the plasma etching time and etching with a basic solution. Furthermore, it proved possible to construct highly hydrophobic nanostructured surfaces that could effectively control the fluid in microchannels at designed pressures. We believe that the fabrication method developed here and the results obtained are valuable contributions towards further applications in the field of micro- and nanofluidics. PMID:26753710

  18. Fabrication and Characterization of Magnetic Nanostructures

    NASA Astrophysics Data System (ADS)

    Scott, Kevin

    Magnetic permalloy nanostructures were fabricated onto a silicon wafer using electron beam lithography and a liftoff process. The lithography was performed with a Hitachi SU-70 SEM retrofitted with a Nabity NPGS lithography conversion kit. PMMA of 950kDa molecular weight was used as the photoresist. Features were either nanowires, nanodots, or elliptical or rectangular nanostructures. The nanowires had dimensions of 15microm x 200nm x 40nm, the nanodots had diameters of 145nm and thickness of 12nm, and the ellipses and rectangles had dimensions of 110nm x 50nm x 13nm. Characterization of the nanostructures was performed using the same Hitachi SEM as well as a Digital Instruments DI 3100 Nanoscope IIIa AFM used in magnetic force imaging mode. The SEM was used to measure lateral dimensions of the features and to capture images of features for proper documentation and for external simulation studies. The MFM was used to capture magnetic images of the samples to determine the magnetic state of the nanowires or arrays.

  19. Fabrication of nanostructures and nanostructure based interfaces for biosensor application

    NASA Astrophysics Data System (ADS)

    Srivastava, Devesh

    Nanoparticles have applications from electronics, composites, drug-delivery, imaging and sensors etc. Fabricating and controlling shape and size of nanoparticles and also controlling the positioning of these particles in 1, 2 or 3-d structures is of most interest. The underlying theme of this study is to develop simple and efficient techniques to fabricate nanoparticles from polymers, and also achieve control in shape, size and functionalization of nanoparticles, while applying them in biosensor applications. First part of the dissertation studies the fabrication of nanostructures using anodized alumina membrane as template. It discusses the fabrication design for injecting polystyrene nanoparticles inside the pores of anodized alumina membranes and heating the membrane to coalesce the particles into tapered nanoparticles. Various parameters like temperature and amount of injected particles can vary the size and shape of fabricated nanoparticles. Later it focuses on the fabrication of metallic nanostructures using the alumina membranes without the aid of the injection system. It utilizes the difference in the functionality of the pore edges of cleaved alumina membrane with respect to the pore walls to first deposit charged polymers using layer-by-layer deposition followed by deposition of nickel. Second part of this study involves immobilization of enzymes for biosensor applications. It describes a biosensor interface developed by immobilization of tyrosinase using layer-by-layer (LBL) deposition process. The interface was modified with functional nanoparticles and their influence on the response of biosensor was studied. Tyrosinase sensor was further extended to develop a novel biosensor which was used to study real time inhibition of NEST, a subunit of the medically relevant membrane protein, neuropathy target esterase. The biosensor was developed to give real time monitoring of dose dependent decrease in activity of NEST. Final part of this study emphasizes on

  20. Boron Nitride Nanostructures: Fabrication, Functionalization and Applications.

    PubMed

    Yin, Jun; Li, Jidong; Hang, Yang; Yu, Jin; Tai, Guoan; Li, Xuemei; Zhang, Zhuhua; Guo, Wanlin

    2016-06-01

    Boron nitride (BN) structures are featured by their excellent thermal and chemical stability and unique electronic and optical properties. However, the lack of controlled synthesis of quality samples and the electrically insulating property largely prevent realizing the full potential of BN nanostructures. A comprehensive overview of the current status of the synthesis of two-dimensional hexagonal BN sheets, three dimensional porous hexagonal BN materials and BN-involved heterostructures is provided, highlighting the advantages of different synthetic methods. In addition, structural characterization, functionalizations and prospective applications of hexagonal BN sheets are intensively discussed. One-dimensional BN nanoribbons and nanotubes are then discussed in terms of structure, fabrication and functionality. In particular, the existing routes in pursuit of tunable electronic and magnetic properties in various BN structures are surveyed, calling upon synergetic experimental and theoretical efforts to address the challenges for pioneering the applications of BN into functional devices. Finally, the progress in BN superstructures and novel B/N nanostructures is also briefly introduced. PMID:27073174

  1. 1D Nanostructures: Controlled Fabrication and Energy Applications

    SciTech Connect

    Hu, Michael Z.

    2013-01-01

    Jian Wei, Xuchun Song, Chunli Yang, and Michael Z. Hu, 1D Nanostructures: Controlled Fabrication and Energy Applications, Journal of Nanomaterials, published special issue (http://www.hindawi.com/journals/jnm/si/197254/) (2013).

  2. Fabrication and Characterization of Flexible and Tunable Plasmonic Nanostructures

    PubMed Central

    Kahraman, Mehmet; Daggumati, Pallavi; Kurtulus, Ozge; Seker, Erkin; Wachsmann-Hogiu, Sebastian

    2013-01-01

    We present a novel method to fabricate flexible and tunable plasmonic nanostructures based on combination of soft lithography and nanosphere lithography, and perform a comprehensive structural and optical characterization of these structures. Spherical latex particles are uniformly deposited on glass slides and used as molds for polydimethylsiloxane to obtain nanovoid structures. The diameter and depth of the nanostructures are controlled by the size of the latex particles. These surfaces are coated with a thin Ag layer for fabrication of uniform plasmonic nanostructures. Structural characterization of these surfaces is performed by SEM and AFM. Optical properties of these plasmonic nanostructures are evaluated via UV/Vis absorption spectroscopy, dark field microscopy, and surface–enhanced Raman spectroscopy (SERS). Position of the surface plasmon absorption depends on the diameter and depth of the nanostructures. SERS enhancement factor (measured up to 1.4 × 106) is dependent on the plasmon absorption wavelength and laser wavelength used in these experiments. PMID:24292236

  3. Maskless fabrication of broadband antireflection nanostructures on glass surfaces

    NASA Astrophysics Data System (ADS)

    Tamayo R, E. E.; Hoshii, T.; Tamaki, R.; Watanabe, K.; Sugiyama, M.; Okada, Y.; Miyano, K.

    2016-06-01

    In order to reduce reflection losses at the surface of glass optical components, we have developed a plasma-etching fabrication method in which a CaF2 mask is self-assembled on the glass surface, generating nanostructures of around 100 nm in size, fabricated with an approximate etching rate of 10 nm per minute, and with controllable height, depending on the process time. By treating glasses with different compositions, it was found that the nanostructures can be successfully fabricated in a glass composed mainly of SiO2, but with 10% CaO content. In addition to the high aspect ratio and tapered geometry of the nanostructures, through cross-section composition analysis, graded Si and O compositions were also found within the nanostructures. The combined contribution of the geometrical and graded composition effects resulted in broadband 96% and over 99% transmittance on one-side and both-side treated glass substrates, respectively.

  4. High resolution fabrication of nanostructures using controlled proximity nanostencil lithography

    NASA Astrophysics Data System (ADS)

    Jain, T.; Aernecke, M.; Liberman, V.; Karnik, R.

    2014-02-01

    Nanostencil lithography has a number of distinct benefits that make it an attractive nanofabrication processes, but the inability to fabricate features with nanometer precision has significantly limited its utility. In this paper, we describe a nanostencil lithography process that provides sub-15 nm resolution even for 40-nm thick structures by using a sacrificial layer to control the proximity between the stencil and substrate, thereby enhancing the correspondence between nanostencil patterns and fabricated nanostructures. We anticipate that controlled proximity nanostencil lithography will provide an environmentally stable, clean, and positive-tone candidate for fabrication of nanostructures with high resolution.

  5. Ion-beam assisted laser fabrication of sensing plasmonic nanostructures

    NASA Astrophysics Data System (ADS)

    Kuchmizhak, Aleksandr; Gurbatov, Stanislav; Vitrik, Oleg; Kulchin, Yuri; Milichko, Valentin; Makarov, Sergey; Kudryashov, Sergey

    2016-01-01

    Simple high-performance, two-stage hybrid technique was developed for fabrication of different plasmonic nanostructures, including nanorods, nanorings, as well as more complex structures on glass substrates. In this technique, a thin noble-metal film on a dielectric substrate is irradiated by a single tightly focused nanosecond laser pulse and then the modified region is slowly polished by an accelerated argon ion (Ar+) beam. As a result, each nanosecond laser pulse locally modifies the initial metal film through initiation of fast melting and subsequent hydrodynamic processes, while the following Ar+-ion polishing removes the rest of the film, revealing the hidden topography features and fabricating separate plasmonic structures on the glass substrate. We demonstrate that the shape and lateral size of the resulting functional plasmonic nanostructures depend on the laser pulse energy and metal film thickness, while subsequent Ar+-ion polishing enables to vary height of the resulting nanostructures. Plasmonic properties of the fabricated nanostructures were characterized by dark-field micro-spectroscopy, Raman and photoluminescence measurements performed on single nanofeatures, as well as by supporting numerical calculations of the related electromagnetic near-fields and Purcell factors. The developed simple two-stage technique represents a new step towards direct large-scale laser-induced fabrication of highly ordered arrays of complex plasmonic nanostructures.

  6. Ion-beam assisted laser fabrication of sensing plasmonic nanostructures.

    PubMed

    Kuchmizhak, Aleksandr; Gurbatov, Stanislav; Vitrik, Oleg; Kulchin, Yuri; Milichko, Valentin; Makarov, Sergey; Kudryashov, Sergey

    2016-01-01

    Simple high-performance, two-stage hybrid technique was developed for fabrication of different plasmonic nanostructures, including nanorods, nanorings, as well as more complex structures on glass substrates. In this technique, a thin noble-metal film on a dielectric substrate is irradiated by a single tightly focused nanosecond laser pulse and then the modified region is slowly polished by an accelerated argon ion (Ar(+)) beam. As a result, each nanosecond laser pulse locally modifies the initial metal film through initiation of fast melting and subsequent hydrodynamic processes, while the following Ar(+)-ion polishing removes the rest of the film, revealing the hidden topography features and fabricating separate plasmonic structures on the glass substrate. We demonstrate that the shape and lateral size of the resulting functional plasmonic nanostructures depend on the laser pulse energy and metal film thickness, while subsequent Ar(+)-ion polishing enables to vary height of the resulting nanostructures. Plasmonic properties of the fabricated nanostructures were characterized by dark-field micro-spectroscopy, Raman and photoluminescence measurements performed on single nanofeatures, as well as by supporting numerical calculations of the related electromagnetic near-fields and Purcell factors. The developed simple two-stage technique represents a new step towards direct large-scale laser-induced fabrication of highly ordered arrays of complex plasmonic nanostructures. PMID:26776569

  7. Ion-beam assisted laser fabrication of sensing plasmonic nanostructures

    PubMed Central

    Kuchmizhak, Aleksandr; Gurbatov, Stanislav; Vitrik, Oleg; Kulchin, Yuri; Milichko, Valentin; Makarov, Sergey; Kudryashov, Sergey

    2016-01-01

    Simple high-performance, two-stage hybrid technique was developed for fabrication of different plasmonic nanostructures, including nanorods, nanorings, as well as more complex structures on glass substrates. In this technique, a thin noble-metal film on a dielectric substrate is irradiated by a single tightly focused nanosecond laser pulse and then the modified region is slowly polished by an accelerated argon ion (Ar+) beam. As a result, each nanosecond laser pulse locally modifies the initial metal film through initiation of fast melting and subsequent hydrodynamic processes, while the following Ar+-ion polishing removes the rest of the film, revealing the hidden topography features and fabricating separate plasmonic structures on the glass substrate. We demonstrate that the shape and lateral size of the resulting functional plasmonic nanostructures depend on the laser pulse energy and metal film thickness, while subsequent Ar+-ion polishing enables to vary height of the resulting nanostructures. Plasmonic properties of the fabricated nanostructures were characterized by dark-field micro-spectroscopy, Raman and photoluminescence measurements performed on single nanofeatures, as well as by supporting numerical calculations of the related electromagnetic near-fields and Purcell factors. The developed simple two-stage technique represents a new step towards direct large-scale laser-induced fabrication of highly ordered arrays of complex plasmonic nanostructures. PMID:26776569

  8. Nanowires, nanostructures and devices fabricated therefrom

    DOEpatents

    Majumdar, Arun; Shakouri, Ali; Sands, Timothy D.; Yang, Peidong; Mao, Samuel S.; Russo, Richard E.; Feick, Henning; Weber, Eicke R.; Kind, Hannes; Huang, Michael; Yan, Haoquan; Wu, Yiying; Fan, Rong

    2005-04-19

    One-dimensional nanostructures having uniform diameters of less than approximately 200 nm. These inventive nanostructures, which we refer to as "nanowires", include single-crystalline homostructures as well as heterostructures of at least two single-crystalline materials having different chemical compositions. Because single-crystalline materials are used to form the heterostructure, the resultant heterostructure will be single-crystalline as well. The nanowire heterostructures are generally based on a semiconducting wire wherein the doping and composition are controlled in either the longitudinal or radial directions, or in both directions, to yield a wire that comprises different materials. Examples of resulting nanowire heterostructures include a longitudinal heterostructure nanowire (LOHN) and a coaxial heterostructure nanowire (COHN).

  9. Fabrication and characterization of metal nanostructures on metal substrates

    NASA Astrophysics Data System (ADS)

    Nikov, Ru. G.; Nedyalkov, N. N.; Atanasov, P. A.; Delaporte, Ph.; Grojo, D.

    2015-01-01

    In this paper we show an experimental procedure for fabrication of metal nanoparticle arrays on metal substrates. The nanostructures are fabricated by laser processing of thin metal films. The films are deposited on the metal substrates by classical PLD technology. The as deposited films are then annealed by nanosecond pulses delivered from a THG Nd:YAG laser system (λ = 355 nm). At certain conditions, the laser treatment leads to a formation of discrete nanoparticle structure on the substrate surface. The optical properties of samples fabricated at different conditions and having different characteristics of the nanostructures are examined by optical spectroscopy measurement. Such analysis shows that the optical spectra of the obtained nanostructures are characterized by plasmon excitation. Finite difference time domain (FDTD) model is used for theoretical description of the near field optical properties of the fabricated nanoparticle arrays. The simulation demonstrates high efficiency of the fabricated structures in enhancement of the near field intensity. The great enhancement observed in the Raman spectra of Rhodamine 6G deposited on the fabricated samples makes such structures very appropriate for applications in Surface Enhanced Raman Spectroscopy (SERS). The produced systems can be also applied in plasmonic solar cells (PSC).

  10. Nanostructures design and fabrication for magnetic storage applications

    NASA Astrophysics Data System (ADS)

    Luo, Yong

    The advent of nanofabrication technology offers capabilities in patterning materials and modifying the magnetic properties. The focus of this research is to design and fabricate magnetic nanostructures and understand the magnetic behavior modified by nanostructures, to generate new devices for magnetic storage applications. First, novel techniques have been successfully developed to fabricate nanostructures with different shapes and dimensions below the resolution limit of photolithography tool. Anisotropic nanostructures, diamonds and triangles, have been obtained by over-exposure technique; nano-rings, both centered and de-centered, have been obtained by lateral etch technique and ALD spacer mask technique. All these techniques are simple and use conventional photolithography. Large area, high density nanostructures have been obtained at low cost. Second, anisotropic nanostructures have been characterized correlated with simulation to understand the shape anisotropy effect on magnetic behavior. Coercivity change and angular dependent behavior result from pinning the magnet by the nanostructures and these have been explored. Dimensions of nanostructure also play an important role in changing the magnetic properties. Third, nano-rings have been characterized correlated with simulation to study the magnetic state switching process. Various dimensions of rings have been compared and have revealed that the vortex state in rings is affected by the dimensions of inner diameter, width and thickness. The shape anisotropy and magnetostatic energy play an important role in vortex state formation and maintenance. The interaction effect in ring array has also been explored for high density MRAM design application. Fourth, feasible design and fabrication of de-centered rings have been developed for vortex chirality control. The asymmetry in the de-centered rings controls the movement direction of the domain walls, leading to predictable vortex chirality. Finally, future

  11. Methods of fabricating nanostructures and nanowires and devices fabricated therefrom

    DOEpatents

    Majumdar,; Arun; Shakouri, Ali; Sands, Timothy D.; Yang, Peidong; Mao, Samuel S.; Russo, Richard E.; Feick, Henning; Weber, Eicke R.; Kind, Hannes; Huang, Michael; Yan, Haoquan; Wu, Yiying; Fan, Rong

    2009-08-04

    One-dimensional nanostructures having uniform diameters of less than approximately 200 nm. These inventive nanostructures, which we refer to as "nanowires", include single-crystalline homostructures as well as heterostructures of at least two single-crystalline materials having different chemical compositions. Because single-crystalline materials are used to form the heterostructure, the resultant heterostructure will be single-crystalline as well. The nanowire heterostructures are generally based on a semiconducting wire wherein the doping and composition are controlled in either the longitudinal or radial directions, or in both directions, to yield a wire that comprises different materials. Examples of resulting nanowire heterostructures include a longitudinal heterostructure nanowire (LOHN) and a coaxial heterostructure nanowire (COHN).

  12. Methods of fabricating nanostructures and nanowires and devices fabricated therefrom

    DOEpatents

    Majumdar, Arun; Shakouri, Ali; Sands, Timothy D.; Yang, Peidong; Mao, Samuel S.; Russo, Richard E.; Feick, Henning; Weber, Eicke R.; Kind, Hannes; Huang, Michael; Yan, Haoquan; Wu, Yiying; Fan, Rong

    2010-11-16

    One-dimensional nanostructures having uniform diameters of less than approximately 200 nm. These inventive nanostructures, which we refer to as "nanowires", include single-crystalline homostructures as well as heterostructures of at least two single-crystalline materials having different chemical compositions. Because single-crystalline materials are used to form the heterostructure, the resultant heterostructure will be single-crystalline as well. The nanowire heterostructures are generally based on a semiconducting wire wherein the doping and composition are controlled in either the longitudinal or radial directions, or in both directions, to yield a wire that comprises different materials. Examples of resulting nanowire heterostructures include a longitudinal heterostructure nanowire (LOHN) and a coaxial heterostructure nanowire (COHN).

  13. Highly efficient and controllable method to fabricate ultrafine metallic nanostructures

    NASA Astrophysics Data System (ADS)

    Cai, Hongbing; Zhang, Kun; Yu, Xinxin; Pan, Nan; Tian, Yangchao; Luo, Yi; Wang, Xiaoping

    2015-11-01

    We report a highly efficient, controllable and scalable method to fabricate various ultrafine metallic nanostructures in this paper. The method starts with the negative poly-methyl-methacrylate (PMMA) resist pattern with line-width superior to 20 nm, which is obtained from overexposing of the conventionally positive PMMA under a low energy electron beam. The pattern is further shrunk to sub-10 nm line-width through reactive ion etching. Using the patter as a mask, we can fabricate various ultrafine metallic nanostructures with the line-width even less than 10 nm. This ion tailored mask lithography (ITML) method enriches the top-down fabrication strategy and provides potential opportunity for studying quantum effects in a variety of materials.

  14. Highly efficient and controllable method to fabricate ultrafine metallic nanostructures

    SciTech Connect

    Cai, Hongbing; Zhang, Kun; Pan, Nan E-mail: xpwang@ustc.edu.cn; Luo, Yi; Wang, Xiaoping E-mail: xpwang@ustc.edu.cn; Yu, Xinxin; Tian, Yangchao

    2015-11-15

    We report a highly efficient, controllable and scalable method to fabricate various ultrafine metallic nanostructures in this paper. The method starts with the negative poly-methyl-methacrylate (PMMA) resist pattern with line-width superior to 20 nm, which is obtained from overexposing of the conventionally positive PMMA under a low energy electron beam. The pattern is further shrunk to sub-10 nm line-width through reactive ion etching. Using the patter as a mask, we can fabricate various ultrafine metallic nanostructures with the line-width even less than 10 nm. This ion tailored mask lithography (ITML) method enriches the top-down fabrication strategy and provides potential opportunity for studying quantum effects in a variety of materials.

  15. Fabrication of gold nanostructures through pulsed laser interference patterning

    SciTech Connect

    Yuan, Dajun Acharya, Ranadip; Das, Suman

    2013-11-25

    In this Letter, we report on the experimental development and computational modeling of a simple, one-step method for the fabrication of diverse 2D and 3D periodic nanostructures derived from gold films on silicon substrates and over areas spanning 1 cm{sup 2}. These nanostructures can be patterned on films of thickness ranging from 50 nm to 500 nm with pulsed interfering laser beams. A finite volume-based inhomogeneous multiphase model of the process shows reasonable agreement with the experimentally obtained topographies and provides insights on the flow physics including normal and radial expansion that results in peeling of film from the substrate.

  16. On the design and fabrication of nanostructures and devices

    NASA Astrophysics Data System (ADS)

    Wei, Wei

    Nanotechnology is emerging into a new frontier in science and technology with potential impact on every aspect of human life. One of the major breakthroughs in today's nanotechnology is the discovery and preparation of new classes of nanomaterials and nanostructures. A large number of nanomaterials and nanostructures are synthesized and characterized with either new or profoundly enhanced properties or phenomena. However, there are several major challenges ahead need to be overcome before any substantial benefits can be brought to the market. One of the challenges that we need to address today is how to effectively integrate useful nanomaterials and nanostrucrures into functional devices and systems. Our mother nature gives us a classic example of how living organisms are built. Starting from a single cell, through its division and growth, it can self-assemble and become functional tissues and organs. Similar self-assemble approach has been adopted as a nano-fabrication technique to assemble nanomaterials and nanostructures into functional nanodevices. This technique has advantages of high precision and nanometer scale resolution. However, it requires a lot of effort to construct a single device and since the properties of individual nanostructures can be different, the fabricated devices may have different properties. In this dissertation, we design and fabricate nanostructures and devices using novel microfabrication techniques. In the first part of the dissertation, the design and fabrication of a variety of nanostructures, such as metal nanowires array, polymer nanowells, and nanostructured surfaces are discussed. In the second part, carbon nanotubes as a novel material has been explored as an example to demonstrate the integration of nanomaterials with novel microfabrication techniques to form a functional device. First, a resistive heating technique is developed to grow carbon nanotubes in localized regions, such as a nichrome heating coil. Then, MEMS micro

  17. Intracavity fabrication of nanostructures on bulk materials

    NASA Astrophysics Data System (ADS)

    Osipov, Vladimir P.; Valyavko, Vasily V.

    2002-05-01

    The analytical and experimental investigations describing the intracavity processing of different solid-sate materials (Al, Cr, Ge, Si) are presented. New designs of the laser cavity were explored to facilitate the fabrication of structures composed of a system of equidistant parallel 250 nm-sized grooves and periodic micro-dots on massive samples of metals and semiconductors, as well as micro-holes in thin film metallic samples.

  18. 3D nanostructures fabricated by advanced stencil lithography.

    PubMed

    Yesilkoy, F; Flauraud, V; Rüegg, M; Kim, B J; Brugger, J

    2016-03-01

    This letter reports on a novel fabrication method for 3D metal nanostructures using high-throughput nanostencil lithography. Aperture clogging, which occurs on the stencil membranes during physical vapor deposition, is leveraged to create complex topographies on the nanoscale. The precision of the 3D nanofabrication method is studied in terms of geometric parameters and material types. The versatility of the technique is demonstrated by various symmetric and chiral patterns made of Al and Au. PMID:26884085

  19. 3D nanostructures fabricated by advanced stencil lithography

    NASA Astrophysics Data System (ADS)

    Yesilkoy, F.; Flauraud, V.; Rüegg, M.; Kim, B. J.; Brugger, J.

    2016-02-01

    This letter reports on a novel fabrication method for 3D metal nanostructures using high-throughput nanostencil lithography. Aperture clogging, which occurs on the stencil membranes during physical vapor deposition, is leveraged to create complex topographies on the nanoscale. The precision of the 3D nanofabrication method is studied in terms of geometric parameters and material types. The versatility of the technique is demonstrated by various symmetric and chiral patterns made of Al and Au.

  20. Fabrication of large arrays of plasmonic nanostructures via double casting

    NASA Astrophysics Data System (ADS)

    Lo, Joanne C.; Horsley, David A.; Skinner, Jack L.

    2012-03-01

    Large arrays of periodic nanostructures are widely used for plasmonic applications, including ultrasensitive particle sensing, optical nanoantennas, and optical computing; however, current fabrication processes (e.g., e-beam lithography and nanoimprint lithography) remain time consuming and expensive. Previously, researchers have utilized double casting methods to effectively fabricate large-scale arrays of microscale features. Despite significant progress, employing such techniques at the nanoscale has remained a challenge due to cracking and incomplete transfer of the nanofeatures. To overcome these issues, here we present a double casting methodology for fabricating large-scale arrays of nanostructures. We demonstrate this technique by creating large (0.5 cm × 1 cm) arrays of 150 nm nanoholes and 150 nm nanopillars from one silicon master template with nanopillars. To preclude cracking and incomplete transfer problems, a hard-PDMS/soft-PDMS (h-PDMS/s-PDMS) composite stamp was used to replicate the features from: (i) the silicon template, and (ii) the resulting PDMS template. Our double casting technique can be employed repeatedly to create positive and negative copies of the original silicon template as desired. By drastically reducing the cost, time, and labor associated with creating separate silicon templates for large arrays of different nanostructures, this methodology will enable rapid prototyping for diverse applications in nanotechnological fields.

  1. How to Fabricate Functional Artificial Luciferases for Bioassays.

    PubMed

    Kim, Sung-Bae; Fujii, Rika

    2016-01-01

    The present protocol introduces fabrication of artificial luciferases (ALuc(®)) by extracting the consensus amino acids from the alignment of copepod luciferase sequences. The made ALucs have unique sequential identities that are phylogenetically distinctive from those of any existing copepod luciferase. Some ALucs exhibited heat stability, and strong and greatly prolonged optical intensities. The made ALucs are applicable to various bioassays as an optical readout, including live cell imaging, single-chain probes, and bioluminescent tags of antibodies. The present protocol guides on how to fabricate a unique artificial luciferase with designed optical properties and functionalities. PMID:27424894

  2. Helical metallic micro- and nanostructures: fabrication and application.

    PubMed

    Liu, Lichun; Zhang, Liqiu; Kim, Sang Min; Park, Sungho

    2014-08-21

    Metal elements occupy more than 70% of the positions in the periodic table, and their use has accelerated human civilization due to their invaluable chemical and physical characteristics. With the rapid development of metals, various structures of microscopic metal particles have been fabricated and investigated as functional materials in scientific research and practical applications. The phrase 'structure determines properties' has been widely acknowledged as a golden rule in chemistry and materials science, especially when the size of small particles is in the micro- or nanoscale dimension. Helical metallic micro- and nanostructures with complex shapes have recently emerged and may be used for various useful applications such as photonics, sensors, actuators, micro-/nanorobotics, and micro-/nanoelectronics, based on their unique mechanical, electrical, and electromagnetic properties. This review paper specifically focuses on the fabrication and application of helical metallic structures with a size ranging from the micro- to nanoscale. The unusual spatial distribution of active atoms in helical metallic micro- and nanostructures and their helical morphology could offer new opportunities for applications beyond those of other conventional metallic and nonmetallic micro- and nanostructures. PMID:24770884

  3. Helical metallic micro- and nanostructures: fabrication and application

    NASA Astrophysics Data System (ADS)

    Liu, Lichun; Zhang, Liqiu; Kim, Sang Min; Park, Sungho

    2014-07-01

    Metal elements occupy more than 70% of the positions in the periodic table, and their use has accelerated human civilization due to their invaluable chemical and physical characteristics. With the rapid development of metals, various structures of microscopic metal particles have been fabricated and investigated as functional materials in scientific research and practical applications. The phrase `structure determines properties' has been widely acknowledged as a golden rule in chemistry and materials science, especially when the size of small particles is in the micro- or nanoscale dimension. Helical metallic micro- and nanostructures with complex shapes have recently emerged and may be used for various useful applications such as photonics, sensors, actuators, micro-/nanorobotics, and micro-/nanoelectronics, based on their unique mechanical, electrical, and electromagnetic properties. This review paper specifically focuses on the fabrication and application of helical metallic structures with a size ranging from the micro- to nanoscale. The unusual spatial distribution of active atoms in helical metallic micro- and nanostructures and their helical morphology could offer new opportunities for applications beyond those of other conventional metallic and nonmetallic micro- and nanostructures.

  4. Fabrication of Large Area Periodic Nanostructures Using Nanosphere Photolithography

    NASA Astrophysics Data System (ADS)

    Wu, Wei; Dey, Dibyendu; Memis, Omer G.; Katsnelson, Alex; Mohseni, Hooman

    2008-10-01

    Large area periodic nanostructures exhibit unique optical and electronic properties and have found many applications, such as photonic band-gap materials, high dense data storage, and photonic devices. We have developed a maskless photolithography method—Nanosphere Photolithography (NSP)—to produce a large area of uniform nanopatterns in the photoresist utilizing the silica micro-spheres to focus UV light. Here, we will extend the idea to fabricate metallic nanostructures using the NSP method. We produced large areas of periodic uniform nanohole array perforated in different metallic films, such as gold and aluminum. The diameters of these nanoholes are much smaller than the wavelength of UV light used and they are very uniformly distributed. The method introduced here inherently has both the advantages of photolithography and self-assembled methods. Besides, it also generates very uniform repetitive nanopatterns because the focused beam waist is almost unchanged with different sphere sizes.

  5. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, T.W. Jr.; Johnson, G.W.; O`Brien, D.W.

    1995-05-09

    A high performance capacitor is fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a ``notepad`` configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The notepad capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density. 5 figs.

  6. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, T.W. Jr.; Johnson, G.W.; O`Brien, D.W.

    1996-01-23

    A high performance capacitor is described which is fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a ``notepad`` configuration composed of 200--300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The ``notepad`` capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density. 5 figs.

  7. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, Jr., Troy W.; Johnson, Gary W.; O'Brien, Dennis W.

    1995-01-01

    A high performance capacitor fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a "notepad" configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The "notepad" capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density.

  8. High performance capacitors using nano-structure multilayer materials fabrication

    DOEpatents

    Barbee, Jr., Troy W.; Johnson, Gary W.; O'Brien, Dennis W.

    1996-01-01

    A high performance capacitor fabricated from nano-structure multilayer materials, such as by controlled, reactive sputtering, and having very high energy-density, high specific energy and high voltage breakdown. The multilayer capacitors, for example, may be fabricated in a "notepad" configuration composed of 200-300 alternating layers of conductive and dielectric materials so as to have a thickness of 1 mm, width of 200 mm, and length of 300 mm, with terminals at each end of the layers suitable for brazing, thereby guaranteeing low contact resistance and high durability. The "notepad" capacitors may be stacked in single or multiple rows (series-parallel banks) to increase the voltage and energy density.

  9. Fabrication and characterization of one dimensional zinc oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Cheng, Chun

    In this thesis, one dimensional (1D) ZnO nanostructures with controlled morphologies, defects and alignment have been fabricated by a simple vapor transfer method. The crystal structures, interfaces, growth mechanisms and optical properties of ZnO nanostructures have been investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. Great efforts have been devoted to the patterned growth and assembly of ZnO nanostructures as well as the stability of ZnO nanowires (NWs). Using carbonized photoresists, a simple and very effective method has been developed for fabricating and patterning high-quality ZnO NW arrays. ZnO NWs from this method show excellent alignment, crystal quality, and optical properties that are independent of the substrates. The carbonized photoresists provide perfect nucleation sites for the growth of aligned ZnO NWs and also perfectly connect to the NWs to form ideal electrodes. This approach is further extended to realize large area growth of different forms of ZnO NW arrays (e.g., the horizontal growth and multilayered ZnO NW arrays) on other kinds of carbon-based materials. In addition, the as-synthesized vertically aligned ZnO NW arrays show a low weighted reflectance (Rw) and can be used as antireflection coatings. Moreover, non c-axis growth of 1D ZnO nanostructures (e.g., nanochains, nanobrushes and nanobelts) and defect related 1D ZnO nanostructures (e.g., Y-shaped twinned nanobelts and hierarchical nanostructures decorated by flowers induced by screw dislocations) is also present. Using direct oxidization of pure Zn at high temperatures in air, uniformed ZnO NWs and tetrapods have been fabricated. The spatially-resolved PL study on these two kinds of nanostructures suggests that the defects leading to the green luminescence (GL) should originate from the structural changes along the legs of the tetrapods. Surface defects in these ZnO nanostructures play an unimportant

  10. Fabrication and characterization of carbon and boron carbide nanostructured materials

    NASA Astrophysics Data System (ADS)

    Reynaud, Sara

    Carbon is present in nature in a variety of allotropes and chemical compounds. Due to reduced dimensionality, nanostructured carbon materials, i.e. single walled carbon nanotubes (SWNTs), are characterized by unique physical and chemical properties. There is a potential for SWNTs use as biological probes and assists for tunable tissue growth in biomedical applications. However, the presumed cytotoxicity of SWNTs requires investigation of the risks of their incorporation into living systems. Boron is not found in nature in elementary form. Boron based materials are chemically complex and exist in various polymorphic forms, i.e. boron carbide (BC). Because BC is a lightweight material with exceptional mechanical and elastic properties, it is the ideal candidate for armor and ballistic applications. However, practical use of BC as armor material is limited because of its anomalous glass-like behaviour at high velocity impacts, which has been linked to stress-induced structural instability in one of BC polymorphs, B12(CCC). Theoretical calculations suggest that formation of B12(CCC) in BC could be suppressed by silicon doping. In the first part of this thesis, biocompatibility of SWNTs is investigated. It is shown that under normal cell implantation conditions, the electrical conductivity of the SWNTs decreases due to an increase in structural disorder. This research suggests that SWNTs can be functionalized by protein and biological cells reducing the risk of cytotoxicity. In the second part of this thesis, boron carbide nanostructured materials are synthesized and investigated. Radio frequency sputtering deposition technique is employed for fabrication of BC (Si free) and BC:Si thin films. Variation of plasma conditions and temperature are found to affect chemical composition, adhesion to the substrate and morphology of the films. It is shown that BC films are predominantly amorphous and a small addition of Si largely improves their mechanical properties. In addition

  11. Recent advances in the fabrication of nanostructured barrier films.

    PubMed

    Gokhale, Ankush A; Lee, Ilsoon

    2014-03-01

    The fabrication of barrier packaging films has gained significant momentum in recent years. Besides its dominance in the food industry as a means to extend the shelf-life of perishable goods and facilitate ease of handling and transportation, the use of barrier films to protect semiconductor and flexible electronics from dust, oxidation and moisture has generated considerable interest in recent years. This has ushered in new challenges for researchers to design and develop novel thin film barrier coatings that could be made available at a fraction of the cost. The emergence of the multidisciplinary field of nanotechnology has provided innovative solutions in the fields of medicine, catalysis and energy. In this review, we will be examining the integration of nanoscience driven techniques with barrier film technology with applications in both food and electronics industry. Details regarding permeation theory, some key parameters governing gas/moisture barrier properties and the market potential of nanostructured barrier films have been included. This review also explores several past and current examples of successful inclusion of functional nanostructured or colloidal materials to fabricate tailor-made barrier films. Finally a brief discussion regarding novel emerging trends for this industry has been included. PMID:24745209

  12. Fabrication of bioinspired nanostructured materials via colloidal self-assembly

    NASA Astrophysics Data System (ADS)

    Huang, Wei-Han

    ultimate strains than nacre and pure GO paper (also synthesized by filtration). Specifically, it exhibits ˜30 times higher fracture energy than filtrated graphene paper and nacre, ˜100 times tougher than filtrated GO paper. Besides reinforced nanocomposites, we further explored the self-assembly of spherical colloids and the templating nanofabrication of moth-eye-inspired broadband antireflection coatings. Binary crystalline structures can be easily accomplished by spin-coating double-layer nonclose-packed colloidal crystals as templates, followed by colloidal templating. The polymer matrix between self-assembled colloidal crystal has been used as a sacrificial template to define the resulting periodic binary nanostructures, including intercalated arrays of silica spheres and polymer posts, gold nanohole arrays with binary sizes, and dimple-nipple antireflection coatings. The binary-structured antireflection coatings exhibit better antireflective properties than unitary coatings. Natural optical structures and nanocomposites teach us a great deal on how to create high performance artificial materials. The bottom-up technologies developed in this thesis are scalable and compatible with standard industrial processes, promising for manufacturing high-performance materials for the benefits of human beings.

  13. Magneto-optical and magneto-transport studies of hexagonal artificial spin ice nano-structures

    NASA Astrophysics Data System (ADS)

    Olivari, Simon; Esien, Kane; Read, Dan

    2015-03-01

    Artificial spin ice structures have attracted a great deal of attention recently and may prove to be useful analogues for frustrated magnetic systems, such as bulk spin ice materials. We will present the results of studying these structures by utilising magneto optical Kerr effect (MOKE) and magneto-transport measurements. We have fabricated hexagonal (also sometimes known as honeycomb) ASI structures from metallic ferromagnetic islands having dimensions close to 1 μm long, 100nm wide and 10nm thick. We have made electrical transport measurements of two types of structure both having similar geometry and electrically connected islands, however the first samples have magnetically connected elements forming the honeycomb networks whereas the second set of samples are formed from magnetically isolated islands. Comparing these structures allows an assessment of the relative contributions from magnetic domain wall (DW) motion and from magnetostatic interactions. The magneto-optical measurements have been made as a function of angle between the field direction and the lattice. The properties observed with NiFe and Co fabricated nanostructures are discussed in relation to the geometries described above.

  14. Fabrication and Characterization of Nanostructured Oxides for Energy Storage

    NASA Astrophysics Data System (ADS)

    Chen, Qian

    Materials for energy storage have become increasingly important in the modern world as alternatives to petrochemical energy sources. Although technology such as lithium-ion batteries and solid oxide fuel cells are in commercial use, improvements must still be made to increase widespread adoption. To this end, nanostructured materials have emerged as potentially impactful solutions, as they can greatly improve the performance of the energy storage device. One goal of this dissertation was to fabricate nanostructured materials through solution-based processing, electrospinning, and controlled annealing for lithium-ion battery electrodes. This project resulted in the formation of porous fibers from inexpensive, nontoxic materials that can be used as high capacity electrodes. Another component of this dissertation was to deposit thin film noble metals and metal oxides via sputtering for metal-air battery cathodes. The results from these experiments indicate that nanostructured thin films could have improved catalytic activity compared to polycrystalline bulk structures, and also were lower cost due to the decrease in material used. The other major portion of this dissertation was to study the fundamental behavior of nanostructured materials for energy storage at a localized level using electrochemical strain microscopy, a technique that is still in its infancy. The measured responses using electrochemical strain microscopy tended to be difficult to interpret, as they contained many different chemical and mechanical contributions. A series of experiments were devised to distinguish among the different mechanisms, comparing differing responses from Vegard strain, ferroelectric behavior, and electrostrictive effects. Given this framework, inhomogeneous lithium iron phosphate was characterized using electrochemical strain microscopy. From these results, it was found that nanocrystalline particles had higher lithium ion diffusivity as compared to microcrystalline particles

  15. Molecular recognition with nanostructures fabricated by photopolymerization within metallic subwavelength apertures

    NASA Astrophysics Data System (ADS)

    Urraca, J. L.; Barrios, C. A.; Canalejas-Tejero, V.; Orellana, G.; Moreno-Bondi, M. C.

    2014-07-01

    The first demonstration of fabrication of submicron lateral resolution molecularly imprinted polymer (MIP) patterns by photoinduced local polymerization within metal subwavelength apertures is reported. The size of the photopolymerized MIP features is finely tuned by the dose of 532 nm radiation. Rhodamine 123 (R123) has been selected as a fluorescent model template to prove the recognition capability of the MIP nanostructures, which has been evaluated by fluorescence lifetime imaging microscopy (FLIM) with single photon timing measurements. The binding selectivity provided by the imprinting effect has been confirmed in the presence of compounds structurally related to R123. These results pave the way to the development of nanomaterial architectures with biomimetic artificial recognition properties for environmental, clinical and food testing.The first demonstration of fabrication of submicron lateral resolution molecularly imprinted polymer (MIP) patterns by photoinduced local polymerization within metal subwavelength apertures is reported. The size of the photopolymerized MIP features is finely tuned by the dose of 532 nm radiation. Rhodamine 123 (R123) has been selected as a fluorescent model template to prove the recognition capability of the MIP nanostructures, which has been evaluated by fluorescence lifetime imaging microscopy (FLIM) with single photon timing measurements. The binding selectivity provided by the imprinting effect has been confirmed in the presence of compounds structurally related to R123. These results pave the way to the development of nanomaterial architectures with biomimetic artificial recognition properties for environmental, clinical and food testing. Electronic supplementary information (ESI) available: Fig. SI.1: chemical structure and acronyms of the different fluorescent dyes; optimization of polymer composition; Table SI.1. Template recovery after polymerization; determination of the binding capacity by equilibrium rebinding

  16. Nanostructured ferroelectrics: fabrication and structure-property relations.

    PubMed

    Han, Hee; Kim, Yunseok; Alexe, Marin; Hesse, Dietrich; Lee, Woo

    2011-10-25

    With the continued demand for ultrahigh density ferroelectric data storage applications, it is becoming increasingly important to scale the dimension of ferroelectrics down to the nanometer-scale region and to thoroughly understand the effects of miniaturization on the materials properties. Upon reduction of the physical dimension of the material, the change in physical properties associated with size reduction becomes extremely difficult to characterize and to understand because of a complicated interplay between structures, surface properties, strain effects from substrates, domain nucleation, and wall motions. In this Review, the recent progress in fabrication and structure-property relations of nanostructured ferroelectric oxides is summarized. Various fabrication approaches are reviewed, with special emphasis on a newly developed stencil-based method for fabricating ferroelectric nanocapacitors, and advantages and limitations of the processes are discussed. Stress-induced evolutions of domain structures upon reduction of the dimension of the material and their implications on the electrical properties are discussed in detail. Distinct domain nucleation, growth, and propagation behaviors in nanometer-scale ferroelectric capacitors are discussed and compared to those of micrometer-scale counterparts. The structural effect of ferroelectric nanocapacitors on the domain switching behavior and cross-talk between neighboring capacitors under external electric field is reviewed. PMID:21919083

  17. Fabrics coated with lubricated nanostructures display robust omniphobicity

    SciTech Connect

    Shillingford, Cicely; MacCallum, Noah; Wong, Tak -Sing; Kim, Philseok; Aizenberg, Joanna

    2013-12-11

    The development of a stain-resistant and pressure-stable textile is desirable for consumer and industrial applications alike, yet it remains a challenge that current technologies have been unable to fully address. Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized by two main components: hydrophobic chemical functionalization and surface roughness. While this approach produces water-resistant surfaces, these materials have critical weaknesses that hinder their practical utility, in particular as robust stain-free fabrics. For example, traditional superhydrophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids, under pressure when impacted by a high-velocity stream of water (e.g., rain), and when exposed to physical forces such as abrasion and twisting. We have recently introduced slippery lubricant-infused porous surfaces (SLIPS), a self-healing, pressure-tolerant and omniphobic surface, to address these issues. However we present the rational design and optimization of nanostructured lubricant-infused fabrics and demonstrate markedly improved performance over traditional superhydrophobic textile treatments: SLIPS-functionalized cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles, omni-repellent properties against various fluids including polar and nonpolar liquids, pressure tolerance and mechanical robustness, all of which are not readily achievable with the state-of-the-art superhydrophobic coatings.

  18. Fabrics coated with lubricated nanostructures display robust omniphobicity

    DOE PAGESBeta

    Shillingford, Cicely; MacCallum, Noah; Wong, Tak -Sing; Kim, Philseok; Aizenberg, Joanna

    2013-12-11

    The development of a stain-resistant and pressure-stable textile is desirable for consumer and industrial applications alike, yet it remains a challenge that current technologies have been unable to fully address. Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized by two main components: hydrophobic chemical functionalization and surface roughness. While this approach produces water-resistant surfaces, these materials have critical weaknesses that hinder their practical utility, in particular as robust stain-free fabrics. For example, traditional superhydrophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids, under pressure when impacted by a high-velocity stream of water (e.g., rain), and whenmore » exposed to physical forces such as abrasion and twisting. We have recently introduced slippery lubricant-infused porous surfaces (SLIPS), a self-healing, pressure-tolerant and omniphobic surface, to address these issues. However we present the rational design and optimization of nanostructured lubricant-infused fabrics and demonstrate markedly improved performance over traditional superhydrophobic textile treatments: SLIPS-functionalized cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles, omni-repellent properties against various fluids including polar and nonpolar liquids, pressure tolerance and mechanical robustness, all of which are not readily achievable with the state-of-the-art superhydrophobic coatings.« less

  19. Fabrics coated with lubricated nanostructures display robust omniphobicity

    SciTech Connect

    Shillingford, C; MacCallum, N; Wong, TS; Kim, P; Aizenberg, J

    2013-12-11

    The development of a stain-resistant and pressure-stable textile is desirable for consumer and industrial applications alike, yet it remains a challenge that current technologies have been unable to fully address. Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized by two main components: hydrophobic chemical functionalization and surface roughness. While this approach produces water-resistant surfaces, these materials have critical weaknesses that hinder their practical utility, in particular as robust stain-free fabrics. For example, traditional superhydrophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids, under pressure when impacted by a high-velocity stream of water (e. g., rain), and when exposed to physical forces such as abrasion and twisting. We have recently introduced slippery lubricant-infused porous surfaces (SLIPS), a self-healing, pressure-tolerant and omniphobic surface, to address these issues. Herein we present the rational design and optimization of nanostructured lubricant-infused fabrics and demonstrate markedly improved performance over traditional superhydrophobic textile treatments: SLIPS-functionalized cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles, omni-repellent properties against various fluids including polar and nonpolar liquids, pressure tolerance and mechanical robustness, all of which are not readily achievable with the state-of-the-art superhydrophobic coatings.

  20. Fabrics coated with lubricated nanostructures display robust omniphobicity.

    PubMed

    Shillingford, Cicely; MacCallum, Noah; Wong, Tak-Sing; Kim, Philseok; Aizenberg, Joanna

    2014-01-10

    The development of a stain-resistant and pressure-stable textile is desirable for consumer and industrial applications alike, yet it remains a challenge that current technologies have been unable to fully address. Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized by two main components: hydrophobic chemical functionalization and surface roughness. While this approach produces water-resistant surfaces, these materials have critical weaknesses that hinder their practical utility, in particular as robust stain-free fabrics. For example, traditional superhydrophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids, under pressure when impacted by a high-velocity stream of water (e.g., rain), and when exposed to physical forces such as abrasion and twisting. We have recently introduced slippery lubricant-infused porous surfaces (SLIPS), a self-healing, pressure-tolerant and omniphobic surface, to address these issues. Herein we present the rational design and optimization of nanostructured lubricant-infused fabrics and demonstrate markedly improved performance over traditional superhydrophobic textile treatments: SLIPS-functionalized cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles, omni-repellent properties against various fluids including polar and nonpolar liquids, pressure tolerance and mechanical robustness, all of which are not readily achievable with the state-of-the-art superhydrophobic coatings. PMID:24334333

  1. Fabrics coated with lubricated nanostructures display robust omniphobicity

    NASA Astrophysics Data System (ADS)

    Shillingford, Cicely; MacCallum, Noah; Wong, Tak-Sing; Kim, Philseok; Aizenberg, Joanna

    2014-01-01

    The development of a stain-resistant and pressure-stable textile is desirable for consumer and industrial applications alike, yet it remains a challenge that current technologies have been unable to fully address. Traditional superhydrophobic surfaces, inspired by the lotus plant, are characterized by two main components: hydrophobic chemical functionalization and surface roughness. While this approach produces water-resistant surfaces, these materials have critical weaknesses that hinder their practical utility, in particular as robust stain-free fabrics. For example, traditional superhydrophobic surfaces fail (i.e., become stained) when exposed to low-surface-tension liquids, under pressure when impacted by a high-velocity stream of water (e.g., rain), and when exposed to physical forces such as abrasion and twisting. We have recently introduced slippery lubricant-infused porous surfaces (SLIPS), a self-healing, pressure-tolerant and omniphobic surface, to address these issues. Herein we present the rational design and optimization of nanostructured lubricant-infused fabrics and demonstrate markedly improved performance over traditional superhydrophobic textile treatments: SLIPS-functionalized cotton and polyester fabrics exhibit decreased contact angle hysteresis and sliding angles, omni-repellent properties against various fluids including polar and nonpolar liquids, pressure tolerance and mechanical robustness, all of which are not readily achievable with the state-of-the-art superhydrophobic coatings.

  2. Rapid fabrication of nano-structured quartz stamps.

    PubMed

    Chuo, Yindar; Landrock, Clint; Omrane, Badr; Hohertz, Donna; Grayli, Sasan V; Kavanagh, Karen; Kaminska, Bozena

    2013-02-01

    Replication of surface nano-structures from a master stamp allows large-area volume production that is otherwise cost prohibitive through conventional direct-write methods, such as electron beam lithography and focused ion beam milling. However, the creation of a master stamp containing sophisticated patterns still requires significant time on such direct-write tools. We demonstrate a method for reducing this tool time by patterning smaller nano-structures, and then enlarging them to the desired size through isotropic etching. We can create circular structures of any arrangement and size, down to the patterning limits of the direct-write tools. Subsequent metal mask deposition, lift-off, and anisotropic etching transforms the circular patterns to out-of-plane pillar structures for the final stamp. A 1 cm(2) area filled with a pattern of 200 nm diameter nano-holes spaced 520 nm apart, requires only 21 h to complete using our process, compared to 75 h using conventional fabrication. We demonstrate the utility and practicality of the quartz stamps through polymer embossing and replication. Embossed polymer nano-hole arrays are coated with a Cr/Au (5/100 nm) film to create surface plasmon resonance structures. Extraordinary optical transmission spectra from the metallized arrays show the expected spectral features when compared to focused ion beam milled structures. PMID:23324651

  3. Silica-gold bilayer-based transfer of focused ion beam-fabricated nanostructures.

    PubMed

    Wu, Xiaofei; Geisler, Peter; Krauss, Enno; Kullock, René; Hecht, Bert

    2015-10-21

    The demand for using nanostructures fabricated by focused ion beam (FIB) on delicate substrates or as building blocks for complex devices motivates the development of protocols that allow FIB-fabricated nanostructures to be transferred from the original substrate to the desired target. However, transfer of FIB-fabricated nanostructures is severely hindered by FIB-induced welding of structure and substrate. Here we present two (ex and in situ) transfer methods for FIB-fabricated nanostructures based on a silica-gold bilayer evaporated onto a bulk substrate. Utilizing the poor adhesion between silica and gold, the nanostructures can be mechanically separated from the bulk substrate. For the ex situ transfer, a spin-coated poly(methyl methacrylate) film is used to carry the nanostructures so that the bilayer can be etched away after being peeled off. For the in situ transfer, using a micro-manipulator inside the FIB machine, a cut-out piece of silica on which a nanostructure has been fabricated is peeled off from the bulk substrate and thus carries the nanostructure to a target substrate. We demonstrate the performance of both methods by transferring plasmonic nano-antennas fabricated from single-crystalline gold flakes by FIB milling to a silicon wafer and to a scanning probe tip. PMID:26395208

  4. Fabrication of artificial graphene in a GaAs heterostructure

    NASA Astrophysics Data System (ADS)

    Scarabelli, Diego; Wang, Sheng; Kuznetsova, Yuliya; Pfeiffer, Loren; West, Ken; Gardner, Geoff; Manfra, Michael; Pellegrini, Vittorio; Pinczuk, Aron; Wind, Shalom

    Engineered honeycomb lattices, known as artificial graphene, constitute a platform for the exploration of graphene-like phenomena in a highly controllable and tunable manner, offering insight into a broader parameter range inaccessible to natural graphene. The electronic states of a 2D electron gas whose density is modulated by a potential with honeycomb topology have been predicted to generate massless Dirac fermions (MDFs) with tunable Fermi velocity. In this work we present the fabrication of artificial graphene in an ultrahigh quality GaAs/AlGaAs quantum well, with lattice period as small as 40nm, the smallest reported so far for this type of system. The combination of high precision electron-beam lithography, used to define an etch mask with honeycomb geometry on the surface of the sample, and precise anisotropic reactive ion etching allows to create artificial graphene with excellent uniformity and long range order. Different methodologies for preparation of the mask are compared and their limits are discussed. Thanks to the achievement of such high-resolution artificial graphene we expected to be able to observe, for the first time, MDFs in an engineered semiconductor and the possibility of access to novel topological phases. Supported by DOE-BES Award DE-SC0010695.

  5. Profile Prediction and Fabrication of Wet-Etched Gold Nanostructures for Localized Surface Plasmon Resonance

    PubMed Central

    2010-01-01

    Dispersed nanosphere lithography can be employed to fabricate gold nanostructures for localized surface plasmon resonance, in which the gold film evaporated on the nanospheres is anisotropically dry etched to obtain gold nanostructures. This paper reports that by wet etching of the gold film, various kinds of gold nanostructures can be fabricated in a cost-effective way. The shape of the nanostructures is predicted by profile simulation, and the localized surface plasmon resonance spectrum is observed to be shifting its extinction peak with the etching time. (See supplementary material 1) PMID:20672106

  6. Fabrication and characterization of hierarchical nanostructured smart adhesion surfaces.

    PubMed

    Lee, Hyungoo; Bhushan, Bharat

    2012-04-15

    The mechanics of fibrillar adhesive surfaces of biological systems such as a Lotus leaf and a gecko are widely studied due to their unique surface properties. The Lotus leaf is a model for superhydrophobic surfaces, self-cleaning properties, and low adhesion. Gecko feet have high adhesion due to the high micro/nanofibrillar hierarchical structures. A nanostructured surface may exhibit low adhesion or high adhesion depending upon fibrillar density, and it presents the possibility of realizing eco-friendly surface structures with desirable adhesion. The current research, for the first time uses a patterning technique to fabricate smart adhesion surfaces: single- and two-level hierarchical synthetic adhesive structure surfaces with various fibrillar densities and diameters that allows the observation of either the Lotus or gecko adhesion effects. Contact angles of the fabricated structured samples were measured to characterize their wettability, and contamination experiments were performed to study for self-cleaning ability. A conventional and a glass ball attached to an atomic force microscope (AFM) tip were used to obtain the adhesive forces via force-distance curves to study scale effect. A further increase of the adhesive forces on the samples was achieved by applying an adhesive to the surfaces. PMID:22285098

  7. Fabrication of optically active nanostructures by chemical methods

    NASA Astrophysics Data System (ADS)

    Moran, Cristin Erin

    A new method of fabricating long-range, planar arrays of discrete, submicron metal structures on glass or SiO2/Si surfaces has been developed without the use of resist masks or chemical etching. The approach combines microcontact printing and electroless plating for the controlled deposition of islands or lines of gold or silver. The metallic structures are varied in size, separation and shape by using a variety of commercial diffraction gratings to mold the polydimethylsiloxane (PDMS) elastomer stamps. An assortment of distinct geometrical patterns have been fabricated and imaged on a range of length scales using scanning probe, scanning electron, and optical microscopies. Additionally, the same chemical techniques can be used to pattern surfaces with biomolecules and ordered arrays of metal nanoshells. These arrays of metal nanostructures support surface plasmon propagation and also show plasmon-plasmon interactions dependent on the geometry of the metal features. These structures were used to investigate the effects of molecular functionalization on the excitation and propagation properties of the surface plasmons that are supported by this geometry. Distinct variations in the dispersion and energy gaps of surface plasmons on these structures due to chemical functionalization of the metal structures is observed. A second type of optically active structure, rare-earth doped silica particles, has been synthesized using wet chemistry. The polydispersity of the particles can be controlled by changing the concentration of dopant salt. These particles may be useful for microlaser or display technologies.

  8. Cellular processing and destinies of artificial DNA nanostructures.

    PubMed

    Lee, Di Sheng; Qian, Hang; Tay, Chor Yong; Leong, David Tai

    2016-08-01

    Since many bionanotechnologies are targeted at cells, understanding how and where their interactions occur and the subsequent results of these interactions is important. Changing the intrinsic properties of DNA nanostructures and linking them with interactions presents a holistic and powerful strategy for understanding dual nanostructure-biological systems. With the recent advances in DNA nanotechnology, DNA nanostructures present a great opportunity to understand the often convoluted mass of information pertaining to nanoparticle-biological interactions due to the more precise control over their chemistry, sizes, and shapes. Coupling just some of these designs with an understanding of biological processes is both a challenge and a source of opportunities. Despite continuous advances in the field of DNA nanotechnology, the intracellular fate of DNA nanostructures has remained unclear and controversial. Because understanding its cellular processing and destiny is a necessary prelude to any rational design of exciting and innovative bionanotechnology, in this review, we will discuss and provide a comprehensive picture relevant to the intracellular processing and the fate of various DNA nanostructures which have been remained elusive for some time. We will also link the unique capabilities of DNA to some novel ideas for developing next-generation bionanotechnologies. PMID:27119124

  9. Fabrication of artificial gemstones from glasses: From waste to jewelry

    NASA Astrophysics Data System (ADS)

    Srisittipokakun, N.; Ruangtaweep, Y.; Horprathum, M.; Kaewkhao, J.

    2014-09-01

    In this review, several aspects of artificial gemstones from glasses have been addressed from the advantages, the fabrication process, the coloration, their properties and finally the use of RHA as the glass former for the simulant gemstones. The silica sources for preparation of glasses were locally obtained from sand and biomass ashes in Thailand. The refractive index, density and hardness values of the glass gemstones reported in these researches had been meet the standard of EU-regulation for crystal. The glass gemstones were fabricated in a variety of colors with some special features such as color changing when exposed under different light sources. Barium was used instead of lead to increase the density and refractive index of the glasses. The developments of high refractive index lead-free glasses are also leave non-toxically impact to our environment.

  10. Nanostructured component fabrication by electron beam-physical vapor deposition

    NASA Astrophysics Data System (ADS)

    Singh, Jogender; Wolfe, Douglas E.

    2005-08-01

    Fabrication of cost-effective, nano-grained net-shaped components has brought considerable interest to Department of Defense, National Aeronautics and Space Administration, and Department of Energy. The objective of this paper is to demonstrate the versatility of electron beam-physical vapor deposition (EB-PVD) technology in engineering new nanostructured materials with controlled microstructure and microchemistry in the form of coatings and net-shaped components for many applications including the space, turbine, optical, biomedical, and auto industries. Coatings are often applied on components to extent their performance and life under severe environmental conditions including thermal, corrosion, wear, and oxidation. Performance and properties of the coatings depend upon their composition, microstructure, and deposition condition. Simultaneous co-evaporation of multiple ingots of different compositions in the high energy EB-PVD chamber has brought considerable interest in the architecture of functional graded coatings, nano-laminated coatings, and design of new structural materials that could not be produced economically by conventional methods. In addition, high evaporation and condensate rates allowed fabricating precision net-shaped components with nanograined microstructure for various applications. Using EB-PVD, nano-grained rhenium (Re) coatings and net-shaped components with tailored microstructure and properties were fabricated in the form of tubes, plates, and Re-coated spherical graphite cores. This paper will also present the results of various metallic and ceramic coatings including chromium, titanium carbide (TiC), titanium diboride (TiB2), hafnium nitride (HfN), titanium-boron-carbonitride (TiBCN), and partially yttria stabilized zirconia (YSZ) TBC coatings deposited by EB-PVD for various applications.

  11. High-speed photocathodes fabricated from metallic nanostructures

    NASA Astrophysics Data System (ADS)

    Nolle, Eduard L.; Khavin, Yuri B.; Schelev, Mikhail Y.

    2005-03-01

    Spectral dependences of photoemission (PE), absorption and reflection from Ag and Au granular films are studied experimentally together with their structure and physical properties using Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPES). It is found that a new intensive PE band in the visible spectral range (l = 500 - 600 nm) appears when such films are activated with Cs and O and this PE band coincides with the absorption and reflection bands. Theoretical calculations of PE spectra based on absorption spectrum of metallic oblate spheroidal nanoparticles are also carried out. Such calculations indicate that the appearance of this PE band can be explained by excitation of the surface plasmons in spheroidal nanoparticles with the major axes approximately equal to 50 nm and minor axes approximately equal to 5 nm. Similar calculations carried out for an S-1 photocathode indicate that the shape and the position of the measured long wavelength PE band with the peak maximum at λ ~ 800 nm can also be explained by excitation of the surface plasmons in Ag spheroidal nanoparticles with the axes equal to 25 and 0.9 nm correspondingly. Degradation with time of PE from Ag and Au granular films is also studied and it is shown that while Ag nanoparticles degrade due to desorption of Cs, Au nanoparticles degrade due to its adsorption. Photoelectron emission in the studied metallic nanostructures can be explained by the surface photoeffect caused by excitation of the surface plasmons in nanoparticles. Therefore, photocathodes with subfemtosecond-range temporal resolution and quantum yield equal to several percent in the visible wavelength range can be fabricated from such nanostructures.

  12. Fabrication, characterization, manipulation and application of magnetic nanostructures

    NASA Astrophysics Data System (ADS)

    Sun, Li

    Nanostructured materials have not only abundant new physics but also application importance. Nanosciences include developing new techniques and exploring new phenomena. This dissertation presents the fabrication and property investigation of magnetic nanowires and exchange coupled NiFe/CoO nanostructured networks. Functionalization and potential biomedical applications of multicomponent nanowires are discussed. Using nuclear track etching, nanopores with controlled areal density (1-1011/cm2) and size (diameter > 10nm) are fabricated in polycarbonate membranes and mica single crystal wafers. Pore morphology depends strongly on the etching properties of the matrix. In contrast to the cylindrical pores in polycarbonate, etched nanopores in single crystalline mica membranes maintain diamond shape cross-sections, as a replica of the oxygen terminated planes of the unit cell. Compared to conventional nanoporous polymer membraness, mica template provides better thermal stability, chemical stability, mechanical rigidity and atomically smooth surfaces. Different materials have been electrodeposited into the pores to form nanowires. Magnetic properties of the electrodeposited Ni nanowires exhibit strong size dependence. Coercivity and remnant magnetization increase with decreasing nanowire diameter. High temperature measurements on the Ni nanowires in mica show finite size effects in the quasi-one dimensional structures. Curie temperature shifts to lower temperature with decreasing wire diameter and follows the finite size scaling law. Due to the diamond shape wire cross-section, in-plane magnetic anisotropy based on two mutually perpendicular anisotropic axes has been observed. We also studied the magnetization reversal process when the external field rotated away from wire axis. In the 120nm Ni nanowires, transition from switching based on curling to coherent rotation has been observed when the angle between the field and wire axis is about 80°. Single nanowire

  13. Nanostructured substrate fabricated by sectioning tendon using a microtome for tissue engineering.

    PubMed

    Dai, Xiaoshu; Xu, Qiaobing

    2011-12-01

    This paper describes an efficient and versatile method for the fabrication of nanostructured substrates from a piece of tendon which comprises aligned collagen nanofibers. We used a microtome to generate the tendon slices (10-50  µm thick), which were used as a scaffold for guiding directional cell growth. Highly aligned and uniform monolayer cells sheets were obtained. The tendon slices were used as a master, and the nanostructures outlined by the bundles of collagen nanofibers were successfully transferred onto a polystyrene film using standard soft lithography. The cell growing on the nanostructured polystyrene substrate showed good adhesion and alignment. The technique developed here enables one to fabricate nanostructured substrates without using any traditional micro/nanofabrication tools. The nanostructured substrate, e.g. a slice of tendon, has excellent biocompatibility and relatively good mechanical stability, which makes this technique useful in constructing complicated 3D tissues. PMID:22101489

  14. Designing micro- and nanostructures for artificial urinary sphincters

    NASA Astrophysics Data System (ADS)

    Weiss, Florian M.; Deyhle, Hans; Kovacs, Gabor; Müller, Bert

    2012-04-01

    The dielectric elastomers are functional materials that have promising potential as actuators with muscle-like mechanical properties due to their inherent compliancy and overall performance: the combination of large deformations, high energy densities and unique sensory capabilities. Consequently, such actuators should be realized to replace the currently available artificial urinary sphincters building dielectric thin film structures that work with several 10 V. The present communication describes the determination of the forces (1 - 10 N) and deformation levels (~10%) necessary for the appropriate operation of the artificial sphincter as well as the response time to master stress incontinence (reaction time less than 0.1 s). Knowing the dimensions of the presently used artificial urinary sphincters, these macroscopic parameters form the basis of the actuator design. Here, we follow the strategy to start from organic thin films maybe even monolayers, which should work with low voltages but only provide small deformations. Actuators out of 10,000 or 100,000 layers will finally provide the necessary force. The suitable choice of elastomer and electrode materials is vital for the success. As the number of incontinent patients is steadily increasing worldwide, it becomes more and more important to reveal the sphincter's function under static and stress conditions to realize artificial urinary sphincters, based on sophisticated, biologically inspired concepts to become nature analogue.

  15. Silica-gold bilayer-based transfer of focused ion beam-fabricated nanostructures

    NASA Astrophysics Data System (ADS)

    Wu, Xiaofei; Geisler, Peter; Krauss, Enno; Kullock, René; Hecht, Bert

    2015-10-01

    The demand for using nanostructures fabricated by focused ion beam (FIB) on delicate substrates or as building blocks for complex devices motivates the development of protocols that allow FIB-fabricated nanostructures to be transferred from the original substrate to the desired target. However, transfer of FIB-fabricated nanostructures is severely hindered by FIB-induced welding of structure and substrate. Here we present two (ex and in situ) transfer methods for FIB-fabricated nanostructures based on a silica-gold bilayer evaporated onto a bulk substrate. Utilizing the poor adhesion between silica and gold, the nanostructures can be mechanically separated from the bulk substrate. For the ex situ transfer, a spin-coated poly(methyl methacrylate) film is used to carry the nanostructures so that the bilayer can be etched away after being peeled off. For the in situ transfer, using a micro-manipulator inside the FIB machine, a cut-out piece of silica on which a nanostructure has been fabricated is peeled off from the bulk substrate and thus carries the nanostructure to a target substrate. We demonstrate the performance of both methods by transferring plasmonic nano-antennas fabricated from single-crystalline gold flakes by FIB milling to a silicon wafer and to a scanning probe tip.The demand for using nanostructures fabricated by focused ion beam (FIB) on delicate substrates or as building blocks for complex devices motivates the development of protocols that allow FIB-fabricated nanostructures to be transferred from the original substrate to the desired target. However, transfer of FIB-fabricated nanostructures is severely hindered by FIB-induced welding of structure and substrate. Here we present two (ex and in situ) transfer methods for FIB-fabricated nanostructures based on a silica-gold bilayer evaporated onto a bulk substrate. Utilizing the poor adhesion between silica and gold, the nanostructures can be mechanically separated from the bulk substrate. For the ex

  16. Large-scale fabrication of flexible metallic nanostructure pairs using interference ablation.

    PubMed

    Zhai, Tianrui; Wang, Yonglu; Liu, Hongmei; Zhang, Xinping

    2015-01-26

    Paired one- and two-dimensional metallic nanostructures are created directly by exposing a thin gold film to the interference pattern between ultraviolet laser pulses, where the gold film is coated onto a soft substrate and is sandwiched by another soft slab. Metallic films in the bright fringes are melted and transformed into nanodroplets that are ejected onto the soft slab forming stretchable nanoisland structures. The pattern of the remaining films is coincident with the dark fringes. Thus, complementary metallic nanostructure pairs were fabricated using a single laser pulse. Fano resonance can be observed in the spectroscopic response of the fabricated nanostructures for TM and TE polarizations simultaneously. This nanofabrication technique may provide an annealing-free approach for the fabrication of flexible metallic nanostructures on a large scale and with low cost. PMID:25835940

  17. Whole Wafer Design and Fabrication for the Alignment of Nanostructures for Chemical Sensor Applications

    NASA Technical Reports Server (NTRS)

    Biaggi-Labiosa, Azlin M.; Hunter, Gary W.

    2013-01-01

    A major objective in aerospace sensor development is to produce sensors that are small in size, easy to batch fabricate and low in cost, and have low power consumption The fabrication of chemical sensors involving nanostructured materials can provide these properties as well as the potential for the development of sensor systems with unique properties and improved performance. However, the fabrication and processing of nanostructures for sensor applications currently is limited in the ability to control their location on the sensor. Currently, our group at NASA Glenn Research Center has demonstrated the controlled placement of nanostructures in sensors using a sawtooth patterned electrode design. With this design the nanostructures are aligned between opposing sawtooth electrodes by applying an alternating current.

  18. Fabrication of Chemically Tunable, Hierarchically Branched Polymeric Nanostructures by Multi-branched Anodic Aluminum Oxide Templates.

    PubMed

    Jo, Hanju; Haberkorn, Niko; Pan, Jia-Ahn; Vakili, Mohammad; Nielsch, Kornelius; Theato, Patrick

    2016-06-28

    In this paper, a template-assisted replication method is demonstrated for the fabrication of hierarchically branched polymeric nanostructures composed of post-modifiable poly(pentafluorophenyl acrylate). Anodic aluminum oxide templates with various shapes of hierarchically branched pores are fabricated by an asymmetric two-step anodization process. The hierarchical polymeric nanostructures are obtained by infiltration of pentafluorophenyl acrylate with a cross-linker and photoinitiator, followed by polymerization and selective removal of the template. Furthermore, the nanostructures containing reactive pentafluorophenyl ester are modified with spiropyran amine via post-polymerization modification to fabricate ultraviolet-responsive nanostructures. This method can be readily extended to other amines and offers a generalized strategy for controlling functionality and wettability of surfaces. PMID:27243550

  19. Exchange bias in two-step artificially grown one-dimensional hybrid Co-BiFeO3 core-shell nanostructures.

    PubMed

    Ali, S S; Li, W J; Javed, K; Shi, D W; Riaz, S; Zhai, G J; Han, X F

    2016-01-29

    One-dimensional core-shell nanostructures consisting of a ferromagnetic cobalt core and a multiferroic BiFeO3 (BFO) shell were fabricated by an artificial two-step methodology. The coupling between the ferromagnetic core and multiferroic shell manifests a significant exchange bias effect which gives a clear demonstration of the anti-ferromagnetic functionality of the BFO shell material. Exchange biases of 30 Oe and 60 Oe are observed at 300 K and at 5 K, respectively. Superparamagnetic contributions at lower temperatures play an important role in contributing to overall magnetic behavior. Dominant shape anisotropy causes parallel alignment of the easy magnetization axis along the axis of core-shell nanowires. A coherent mode of the magnetization reversal mechanism is observed by the angular dependence of coercivity (H c). This versatile two-step methodology can be employed to fabricate and investigate many other hybrid nanostructures leading to a vast scope of investigation for researchers. PMID:26656305

  20. Exchange bias in two-step artificially grown one-dimensional hybrid Co-BiFeO3 core-shell nanostructures

    NASA Astrophysics Data System (ADS)

    Ali, S. S.; Li, W. J.; Javed, K.; Shi, D. W.; Riaz, S.; Zhai, G. J.; Han, X. F.

    2016-01-01

    One-dimensional core-shell nanostructures consisting of a ferromagnetic cobalt core and a multiferroic BiFeO3 (BFO) shell were fabricated by an artificial two-step methodology. The coupling between the ferromagnetic core and multiferroic shell manifests a significant exchange bias effect which gives a clear demonstration of the anti-ferromagnetic functionality of the BFO shell material. Exchange biases of 30 Oe and 60 Oe are observed at 300 K and at 5 K, respectively. Superparamagnetic contributions at lower temperatures play an important role in contributing to overall magnetic behavior. Dominant shape anisotropy causes parallel alignment of the easy magnetization axis along the axis of core-shell nanowires. A coherent mode of the magnetization reversal mechanism is observed by the angular dependence of coercivity (H c). This versatile two-step methodology can be employed to fabricate and investigate many other hybrid nanostructures leading to a vast scope of investigation for researchers.

  1. A method to fabricate disconnected silver nanostructures in 3D.

    PubMed

    Vora, Kevin; Kang, SeungYeon; Mazur, Eric

    2012-01-01

    The standard nanofabrication toolkit includes techniques primarily aimed at creating 2D patterns in dielectric media. Creating metal patterns on a submicron scale requires a combination of nanofabrication tools and several material processing steps. For example, steps to create planar metal structures using ultraviolet photolithography and electron-beam lithography can include sample exposure, sample development, metal deposition, and metal liftoff. To create 3D metal structures, the sequence is repeated multiple times. The complexity and difficulty of stacking and aligning multiple layers limits practical implementations of 3D metal structuring using standard nanofabrication tools. Femtosecond-laser direct-writing has emerged as a pre-eminent technique for 3D nanofabrication.(1,2) Femtosecond lasers are frequently used to create 3D patterns in polymers and glasses.(3-7) However, 3D metal direct-writing remains a challenge. Here, we describe a method to fabricate silver nanostructures embedded inside a polymer matrix using a femtosecond laser centered at 800 nm. The method enables the fabrication of patterns not feasible using other techniques, such as 3D arrays of disconnected silver voxels.(8) Disconnected 3D metal patterns are useful for metamaterials where unit cells are not in contact with each other,(9) such as coupled metal dot(10,11)or coupled metal rod(12,13) resonators. Potential applications include negative index metamaterials, invisibility cloaks, and perfect lenses. In femtosecond-laser direct-writing, the laser wavelength is chosen such that photons are not linearly absorbed in the target medium. When the laser pulse duration is compressed to the femtosecond time scale and the radiation is tightly focused inside the target, the extremely high intensity induces nonlinear absorption. Multiple photons are absorbed simultaneously to cause electronic transitions that lead to material modification within the focused region. Using this approach, one can

  2. Fabrication of superhydrophobic polymethylsilsesquioxane nanostructures on cotton textiles by a solution-immersion process.

    PubMed

    Shirgholami, Mohammad A; Khalil-Abad, Mohammad Shateri; Khajavi, Ramin; Yazdanshenas, Mohammad E

    2011-07-15

    Superhydrophobic cotton textiles are prepared by a simple, one-step and inexpensive phase separation method under ambient conditions by which a layer of polymethylsilsesquioxane (PMSQ) nanostructures is covered onto the cellulose fibers. By changing the silane precursor concentration, PMSQ nanostructures with various shapes, morphologies and sizes were fabricated. Nanostructures were characterized using SEM, EDS, and attenuated total reflectance FTIR. The wettability of the modified cellulose surfaces was characterized with contact-angle goniometry and sliding angle technique, respectively. The water contact angle of modified cotton is measured to be higher than 150°, which is high enough to exhibit the lotus effect as a result of the superhydrophobicity. Tunable water-repellent properties of the fabric are also demonstrated, with sliding contact angles varying from "sticky" to "slippery" depending upon different nanostructures on the surface of the fibers. It is expected that this simple technique will accelerate the large-scale production of superhydrophobic cellulosic materials with new industrial applications. PMID:21536303

  3. Resist-free antireflective nanostructured film fabricated by thermal-NIL

    NASA Astrophysics Data System (ADS)

    Kang, Young Hun; Han, Jae Hyung; Cho, Song Yun; Choi, Choon-Gi

    2014-05-01

    Resist-free antireflective (AR) nanostructured films are directly fabricated on polycarbonate (PC) film using thermal-nanoimprint lithography (T-NIL) and the moth-eye shape of AR nanostructure is elaborately optimized with different oxygen reactive ion etching conditions. Anodic aluminum oxide (AAO) templates are directly used as master molds of T-NIL for preparation of AR nanostructures on PC film without an additional T-NIL resist. AR nanostructures are well arranged with a period of about 200 nm and diameter of about 150 nm, which corresponds to those of the AAO template mold. The moth-eye AR nanostructures exhibit the average reflectance of 2% in wavelength range from 400 to 800 nm. From the results, highly enhanced AR properties with simple direct imprinting on PC film demonstrate the potential for panel application in the field of flat display, touch screen, and solar cells.

  4. Fabrication of Hybrid Nanostructures via Nanoscale Laser-Induced Reshaping for Advanced Light Manipulation.

    PubMed

    Zuev, Dmitry A; Makarov, Sergey V; Mukhin, Ivan S; Milichko, Valentin A; Starikov, Sergey V; Morozov, Ivan A; Shishkin, Ivan I; Krasnok, Alexander E; Belov, Pavel A

    2016-04-01

    Ordered hybrid nanostructures for nanophotonics applications are fabricated by a novel approach via femtosecond laser melting of asymmetric metal-dielectric (Au/Si) nanoparticles created by lithographical methods. The approach allows selective reshaping of the metal components of the hybrid nanoparticles without affecting the dielectric ones and is applied for tuning of the scattering properties of the hybrid nanostructures in the visible range. PMID:26901635

  5. Fabrication of nanostructured Al-doped ZnO thin film for methane sensing applications

    NASA Astrophysics Data System (ADS)

    Shafura, A. K.; Sin, N. D. Md.; Azhar, N. E. I.; Saurdi, I.; Uzer, M.; Mamat, M. H.; Shuhaimi, A.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

    2016-07-01

    CH4 gas sensor was fabricated using spin-coating method of the nanostructured ZnO thin film. Effect of annealing temperature on the electrical and structural properties of the film was investigated. Dense nanostructured ZnO film are obtained at higher annealing temperature. The optimal condition of annealing temperature is 500°C which has conductivity and sensitivity value of 3.3 × 10-3 S/cm and 11.5%, respectively.

  6. TOPICAL REVIEW: Fabrication and characterization of nanostructures on insulator substrates by electron-beam-induced deposition

    NASA Astrophysics Data System (ADS)

    Song, Minghui; Furuya, Kazuo

    2008-04-01

    The fabrication, characterization, and decoration with metallic nanoparticles of nanostructures such as nanowhiskers, nanodendrites, and fractal-like nanotrees on insulator substrates by electron-beam-induced deposition (EBID) are reviewed. Nanostructures with different morphologies of whiskers, dendrites, or trees are fabricated on insulator (Al2O3 or SiO2) substrates by EBID in transmission electron microscopes by controlling the irradiation conditions such as the electron beam intensity. The growth of the nanostructure is related to the accumulation of charges on the surface of a substrate during electron-beam irradiation. A high concentration of the target metallic element and nanocrystal grains of the element are contained in the fabricated nanostructures. The process of growth of the nanostructures is explained qualitatively on the basis of mechanisms in which the formation of the nanostructures is considered to be related to the nanoscaled unevenness of the charge distribution on the surface of the substrate, the movement of the charges to the convex surface of the substrate, and the accumulation of charges at the tip of the grown nanostructure. Novel composite structures of Pt nanoparticle/tungsten (W) nanodendrite or Au nanoparticle/W nanodendrite are fabricated by the decoration of W nanodendrites with metallic elements. Because they have superior features, such as a large specific surface area, a freestanding structure on substrates, a typical size of several nanometers of the tip or the branch, and high purity, the nanostructures may have applications in technologies such as catalysts, sensors, and electron emitters. However, there are still some subjects that should be further studied before their application.

  7. A Stretchable Electronic Fabric Artificial Skin with Pressure-, Lateral Strain-, and Flexion-Sensitive Properties.

    PubMed

    Ge, Jin; Sun, Li; Zhang, Fu-Rui; Zhang, Ye; Shi, Lu-An; Zhao, Hao-Yu; Zhu, Hong-Wu; Jiang, Hai-Long; Yu, Shu-Hong

    2016-01-27

    A stretchable and multiple-force-sensitive electronic fabric based on stretchable coaxial sensor electrodes is fabricated for artificial-skin application. This electronic fabric, with only one kind of sensor unit, can simultaneously map and quantify the mechanical stresses induced by normal pressure, lateral strain, and flexion. PMID:26618615

  8. High speed fabrication of aluminum nanostructures with 10 nm spatial resolution by electrochemical replication.

    PubMed

    Biring, Sajal; Tsai, Kun-Tong; Sur, Ujjal Kumar; Wang, Yuh-Lin

    2008-09-01

    A high fidelity electrochemical replication technique for the rapid fabrication of Al nanostructures with 10 nm lateral resolution has been successfully demonstrated. Aluminum is electrodeposited onto a lithographically patterned Si master using a non-aqueous organic hydride bath of aluminum chloride and lithium aluminum hydride at room temperature. Chemical pretreatment of the Si surface allows a clean detachment of the replicated Al foil from the master, permitting its repetitive use for mass replication. This high throughput technique opens up new possibilities in the fabrication of Al-related nanostructures, including the growth of long range ordered anodic alumina nanochannel arrays. PMID:21828842

  9. Nanostructured target fabrication with metal and semiconductor nanoparticles

    NASA Astrophysics Data System (ADS)

    Barberio, M.; Antici, P.

    2015-10-01

    The development of ultra-intense high-energy (≫1 J) short (<1 ps) laser pulses in the last decade has enabled the acceleration of high-energy short-pulse proton beams. A key parameter for enhancing the acceleration regime is the laser-to-target absorption, which heavily depends on the target structure and material. In this work, we present the realization of a nanostructured target with a sub-laser wavelength nano-layer in the front surface as a possible candidate for improving the absorption. The nanostructured film was realized by a simpler and cheaper method than using conventional lithographic techniques: A colloidal solution of metallic or semiconductor nanoparticles (NPs) was produced by laser ablation and, after a heating and sonication process, was spray-dried on the front surface of an aluminum target. The obtained nanostructured film with a thickness of 1 μm appears, at morphological and chemical analysis, uniformly nanostructured and distributed on the target surface without the presence of oxides or external contaminants. Finally, the size of the NPs can be tuned from tens to hundreds of nanometers simply by varying the growth parameters (i.e., irradiation time, fluence, and laser beam energy).

  10. The design, fabrication, and photocatalytic utility of nanostructured semiconductors: focus on TiO2-based nanostructures

    PubMed Central

    Banerjee, Arghya Narayan

    2011-01-01

    Recent advances in basic fabrication techniques of TiO2-based nanomaterials such as nanoparticles, nanowires, nanoplatelets, and both physical- and solution-based techniques have been adopted by various research groups around the world. Our research focus has been mainly on various deposition parameters used for fabricating nanostructured materials, including TiO2-organic/inorganic nanocomposite materials. Technically, TiO2 shows relatively high reactivity under ultraviolet light, the energy of which exceeds the band gap of TiO2. The development of photocatalysts exhibiting high reactivity under visible light allows the main part of the solar spectrum to be used. Visible light-activated TiO2 could be prepared by doping or sensitizing. As far as doping of TiO2 is concerned, in obtaining tailored material with improved properties, metal and nonmetal doping has been performed in the context of improved photoactivity. Nonmetal doping seems to be more promising than metal doping. TiO2 represents an effective photocatalyst for water and air purification and for self-cleaning surfaces. Additionally, it can be used as an antibacterial agent because of its strong oxidation activity and superhydrophilicity. Therefore, applications of TiO2 in terms of photocatalytic activities are discussed here. The basic mechanisms of the photoactivities of TiO2 and nanostructures are considered alongside band structure engineering and surface modification in nanostructured TiO2 in the context of doping. The article reviews the basic structural, optical, and electrical properties of TiO2, followed by detailed fabrication techniques of 0-, 1-, and quasi-2-dimensional TiO2 nanomaterials. Applications and future directions of nanostructured TiO2 are considered in the context of various photoinduced phenomena such as hydrogen production, electricity generation via dye-sensitized solar cells, photokilling and self-cleaning effect, photo-oxidation of organic pollutant, wastewater management, and

  11. Nano-structured TiO2 film fabricated at room temperature and its acoustic properties

    PubMed Central

    Zhu, Jie; Cao, Wenwu; Jiang, Bei; Zhang, D S; Zheng, H; Zhou, Q; Shung, K K

    2009-01-01

    Nano-structured TiO2 thin film has been successfully fabricated at room temperature. Using a quarter wavelength characterization method, we have measured the acoustic impedance of this porous film, which can be adjusted from 5.3 to 7.19 Mrayl by curing it at different temperatures. The uniform microstructure and easy fabrication at room temperature make this material an excellent candidate for matching layers of ultra-high frequency ultrasonic imaging transducers. PMID:19672322

  12. Controllable fabrication of PS/Ag core-shell-shaped nanostructures

    PubMed Central

    2012-01-01

    In this paper, based on the previous steps, a facile in situ reduction method was developed to controllably prepare polystyrene/Ag (PS/Ag) core-shell-shaped nanostructures. The crucial procedure includes surface treatment of polystyrene core particles by cationic polyelectrolyte polyethyleneimine, in situ formation of Ag nanoparticles, and immobilization of the Ag nanoparticles onto the surface of the polystyrene colloids via functional group NH from the polyethyleneimine. The experimental parameters, such as the reaction temperature, the reaction time, and the silver precursors were optimized for improvement of dispersion and Ag coat coverage of the core-shell-shaped nanostructures. Ultimately, the optimum parameters were obtained through a series of experiments, and well-dispersed, uniformly coated PS/Ag core-shell-shaped nanostructures were successfully fabricated. The formation mechanism of the PS/Ag core-shell-shaped nanostructures was also explained. PMID:23092195

  13. Fabrication of shape controlled Fe{sub 3}O{sub 4} nanostructure

    SciTech Connect

    Zheng, Y.Y.; Wang, X.B.; Shang, L.; Li, C.R.; Cui, C.; Dong, W.J.; Tang, W.H.; Chen, B.Y.

    2010-04-15

    Shape-controlled Fe{sub 3}O{sub 4} nanostructure has been successfully prepared using polyethylene glycol as template in a water system at room temperature. Different morphologies of Fe{sub 3}O{sub 4} nanostructures, including spherical, cubic, rod-like, and dendritic nanostructure, were obtained by carefully controlling the concentration of the Fe{sup 3+}, Fe{sup 2+}, and the molecular weight of the polyethylene glycol. Transmission Electron Microscope images, X-ray powder diffraction patterns and magnetic properties were used to characterize the final product. This easy procedure for Fe{sub 3}O{sub 4} nanostructure fabrication offers the possibility of a generalized approach to the production of single and complex nanocrystalline oxide with tunable morphology.

  14. Design and Fabrication of Carbon Nano-structured Flexible Antenna

    NASA Astrophysics Data System (ADS)

    Lamba, V. K.; Kumar, A.; Verma, M.; Dhariwal, S.; Sharma, K.; Anand, S.; Engles, D.

    2012-10-01

    With a development and an increasing interest in flexible electronics, for civil, medical, space, and military domains, we present a design of a patch antenna using CNT-polymer ink on fabrics. We have prepared CNT ink, and measured its properties to use as a conducting material for making patches. The antenna is designed on cotton and Songket fabric that resonates at 2.3GHz on a 1.23 mm, and 1.06 mm thick fabric substrate with ɛr ≍ 1.7, and ɛr ≍ 1.9 for cotton and Songket respectively. Measured and simulation results shows that band width depends on thickness and type of fabrics we used. All antenna parameters such as VSWR, return loss, gain and radiation pattern meet the design criteria.

  15. Structure-related antibacterial activity of a titanium nanostructured surface fabricated by glancing angle sputter deposition

    NASA Astrophysics Data System (ADS)

    Sengstock, Christina; Lopian, Michael; Motemani, Yahya; Borgmann, Anna; Khare, Chinmay; Buenconsejo, Pio John S.; Schildhauer, Thomas A.; Ludwig, Alfred; Köller, Manfred

    2014-05-01

    The aim of this study was to reproduce the physico-mechanical antibacterial effect of the nanocolumnar cicada wing surface for metallic biomaterials by fabrication of titanium (Ti) nanocolumnar surfaces using glancing angle sputter deposition (GLAD). Nanocolumnar Ti thin films were fabricated by GLAD on silicon substrates. S. aureus as well as E. coli were incubated with nanostructured or reference dense Ti thin film test samples for one or three hours at 37 °C. Bacterial adherence, morphology, and viability were analyzed by fluorescence staining and scanning electron microscopy and compared to human mesenchymal stem cells (hMSCs). Bacterial adherence was not significantly different after short (1 h) incubation on the dense or the nanostructured Ti surface. In contrast to S. aureus the viability of E. coli was significantly decreased after 3 h on the nanostructured film compared to the dense film and was accompanied by an irregular morphology and a cell wall deformation. Cell adherence, spreading and viability of hMSCs were not altered on the nanostructured surface. The results show that the selective antibacterial effect of the cicada wing could be transferred to a nanostructured metallic biomaterial by mimicking the natural nanocolumnar topography.

  16. Fabrication of Nanostructure 1050/6061 Complex Al Alloy by Accumulative Roll-Bonding Process.

    PubMed

    Lee, Seong-Hee; Kim, Jung Han

    2015-01-01

    A nanostructure AA1050/AA6061 complex aluminum alloy was successfully fabricated by the accumulative roll-bonding (ARB) process. The ARB process was performed up to 5 cycles without a lubricant at ambient temperature. The samples fabricated by the ARB were the multi-layer complex aluminum alloys in which AA1050 and AA6061 layers are alternately stacked. The tensile strength of the samples increased with proceeding of the ARB, it reached about 300 MPa which is about twice that of the as-received AA6061. The grain size was greatly reduced to submicron order during the ARB, the efficiency of grain refinement was greater in AA6061 than AA1050. The tensile fracture surfaces showed a mixed morphology of brittle and ductile fracture. It was also found that a nanostructure multi-layer AA1050/AA6061 alloy fabricated by the ARB exhibited very complex microstructure and texture. PMID:26328381

  17. Fabrication of large area nanostructures with surface modified silica spheres

    NASA Astrophysics Data System (ADS)

    Kang, Kwang-Sun

    2014-03-01

    Surface modification of silica spheres with 3-(trimethoxysilyl)propylmethacrylate (TMSPM) has been performed at ambient condition. However, the FTIR spectra and field emission scanning electron microscope (FESEM) images show no evidence of the surface modification. The reaction temperatures were varied from 60 to 80 °C with various reaction periods. Small absorption shoulder of the CO stretching vibration was at 1700 cm-1, and slightly increased with the increase of the reaction time at 60 °C. The clear absorption peak appeared at 1698 cm-1 for the spheres reacted for 80 min at 70 °C and shifted toward 1720 cm-1 with the increase the reaction time. Strong absorption peak showed at 1698 cm-1 and shifted toward 1725 cm-1 with the increase of the reaction time at 80 °C. The spheres were dispersed to methanol and added photoinitiator (Irgacure-184). The solution was poured to a patterned glass substrate and exposed to the 254 nm UV-light during a self-assembly process. A large area and crack-free silica sphere film was formed. To increase the mechanical stability, a cellulose acetate solution was spin-coated to the film. The film was lift-off from the glass substrate to analyze the surface nanostructures. The surface nanostructures were maintained, and the film is stable enough to use as a mold to duplicate the nanopattern and flexible.

  18. Fabrication of TiN nanostructure as a hydrogen peroxide sensor by oblique angle deposition

    PubMed Central

    2014-01-01

    Nanostructured titanium nitride (TiN) films with varying porosity were prepared by the oblique angle deposition technique (OAD). The porosity of films increases as the deposition angle becomes larger. The film obtained at an incident angle of 85° exhibits the best catalytic activity and sensitivity to hydrogen peroxide (H2O2). This could be attributed to its largest contact area with the electrolyte. An effective approach is thus proposed to fabricate TiN nanostructure as H2O2 sensor by OAD. PMID:24589278

  19. Crystalline micro/nanostructures fabrication on silicon using femtosecond laser

    NASA Astrophysics Data System (ADS)

    Deng, Guoliang; Yang, Xianheng; Feng, Guoying; Zhou, Shouhuan

    2015-02-01

    The laser induced micro/ nano-meter size surface structures are fabricated by multi linear polarized femtosecond laser pulses (pulse duration τ=35 fs, wavelength λ=800 nm) irradiation at room temperature(25 ° ) and 400 °. The structures fabricated at these two temperatures show distinct temperature dependence. The grooves, which are parallel to the polarization of the laser light, can be clearly observed at almost all the structured area formed at 400 ° while laser induced period structures(ripples) are the most pronounced surface structure in the crater formed at room temperature. The crystallinity of these surface structures are investigated by using Raman spectroscopy. The Raman spectrum shows that all the structured area formed at 400 ° is crystalline(or poly-crystalline) while amorphous silicon can be observed within the structures formed at room temperature (25 °). These results indicate that temperature is an important parameter to be tuned to tailor the micro/nano-structure fabrication.

  20. Fabrication of Luminescent Nanostructures by Dip-Pen Nanolithography

    SciTech Connect

    Noy, A; Miller, A E; Klare, J E; Weeks, B L; Woods, B W; DeYoreo, J J

    2002-06-25

    We used a combination of dip-pen nanolithography and scanning optical confocal microscopy to fabricate and visualize luminescent nanoscale patterns of various materials on glass substrates. We show that this method can be used successfully to push the limits of dip-pen nanolithography down to controlled deposition of single molecules. We also demonstrate that this method is able to create and visualize protein patterns on surfaces. Finally, we show that our method can be used to fabricate polymer nanowires of controlled size using conductive polymers. We also present a kinetic model that accurately describes the deposition process.

  1. Fabrication of superhydrophobic nanostructured surface on aluminum alloy

    NASA Astrophysics Data System (ADS)

    Jafari, R.; Farzaneh, M.

    2011-01-01

    A superhydrophobic surface was prepared by consecutive immersion in boiling water and sputtering of polytetrafluoroethylene (PTFE or Teflon®) on the surface of an aluminum alloy substrate. Immersion in boiling water was used to create a micro-nanostructure on the alloy substrate. Then, the rough surface was coated with RF-sputtered Teflon film. The immersion time in boiling water plays an important role in surface morphology and water repellency of the deposited Teflon coating. Scanning electron microscopy images showed a "flower-like" structure in first few minutes of immersion. And as the immersion time lengthened, a "cornflake" structure appeared. FTIR analyses of Teflon-like coating deposited on water treated aluminum alloy surfaces showed fluorinated groups, which effectively reduce surface energy. The Teflon-like coating deposited on a rough surface achieved with five-minute immersion in boiling water provided a high static contact angle (˜164°) and low contact angle hysteresis (˜4°).

  2. Design and fabrication of zwitter-wettable nanostructured films.

    PubMed

    Lee, Hyomin; Gilbert, Jonathan B; Angilè, Francesco E; Yang, Rong; Lee, Daeyeon; Rubner, Michael F; Cohen, Robert E

    2015-01-14

    Manipulating surface properties using chemistry and roughness has led to the development of advanced multifunctional surfaces. Here, in a nanostructured polymer film consisting of a hydrophilic reservoir of chitosan/carboxymethyl cellulose capped with various hydrophobic layers, we demonstrate the role of a third design factor, water permeation rate. We use this additional design criterion to produce antifogging coatings that readily absorb water vapor while simultaneously exhibiting hydrophobic character to liquid water. These zwitter-wettable films, produced via aqueous layer-by-layer assembly, consist of a nanoscale thin hydrophobic capping layer (chitosan/Nafion) that enables water vapor to diffuse rapidly into the underlying hydrophilic reservoir rather than nucleating drops of liquid water on the surface. We characterize these novel films using a quartz crystal microbalance with dissipation monitoring (QCM-D) and via depth-profiling X-ray photoelectron spectroscopy (XPS) in addition to extensive testing for fogging/antifogging performance. PMID:25494724

  3. One-step fabrication of nanostructured Ni film with lotus effect from deep eutectic solvent.

    PubMed

    Gu, Changdong; Tu, Jiangping

    2011-08-16

    We report a procedure to fabricate nanostructured Ni films via programmed electrochemical deposition from a choline-chloride-based ionic liquid at a high temperature of 90 °C. Three electrodeposition modes using constant voltage, pulse voltage, and reverse pulse voltage produce a variety of nanostructured Ni films with micro/nanobinary surface architectures, such as nanosheets, aligned nanostrips, and hierarchical flowers. The nanostructured Ni films possess face-centered cubic crystal structure. Amazingly, it is found that the electrodeposited Ni films deliver the superhydrophobic surfaces without any further modifications by low surface-energy materials, which might be attributed to the vigorous micro/nanobinary architectures and the surface chemical composition. The electrochemical measurements reveal that the superhydrophobic Ni film exhibit an obvious passivation phenomenon, which could provide enhanced corrosion resistance for the substrate in the aqueous solutions. PMID:21739965

  4. Fabrication, device assembly, and application of one-dimensional chalcogenides nanostructures

    NASA Astrophysics Data System (ADS)

    Kum, Maxwell Chun Man

    Nanotechnology has received a tremendous amount of research interests ever since the first discovery of carbon nanotubes. One-dimensional nanostructures, such as nanorods, nanowires, nanobelts as well as nanotubes, are of significant interest because of their potential application as interconnects and functional units in nanoscale electrical, optoelectronic, electrochemical, electromechanical, thermoelectric, spintronic, photovoltaic, and sensory devices. Nanoscale one-dimensional devices promise to deliver improved performance, to miniaturize bulky devices, to enable higher density nanoscale devices, and to lower energy consumption. As the radius of these one-dimensional nanostructures fall below the exciton Bohr radius of their respective materials, the structural morphology and size effectively modulates the fundamental electrical, optical, and magnetic properties due to quantum confinement effect. In addition, the high surface to volume ratio of one-dimensional nanostructures enables the device properties to be extremely sensitivity to the environment which is particularly attractive for sensing application. Currently, the focuses of nanotechnology research are (1) the fabrication technique with control over the composition, crystal structure, morphology, and size, (2) the device assembly of nanostructures into complex functional devices, and (3) the characterization and application of these nanoscale devices. There are a multitude of fabrication techniques for one-dimensional nanostructures, including but not exclusively, vapor-solid, vapor-liquid-solid, colloidal, solution-liquid-solid, self-assembly, and template directed electrodeposition. As one-dimensional nanostructures are produced, several techniques are available to assemble them into functional complex nanoscale devices, including but not exclusively, electron beam lithography, focus ion beam, magnetic assembly, and AC dielectrophoretic alignment. In this work, one-dimensional cadmium telluride (Cd

  5. Fabrication of transition metal-containing nanostructures via polymer templates for a multitude of applications

    NASA Astrophysics Data System (ADS)

    Lu, Jennifer Qing

    Nanostructures such as carbon nanotubes and semiconducting nanowires offer great technological promise due to their remarkable properties. The lack of a rational synthesis method prevents fabricating these nanostructures with desirable and consistent properties at predefined locations for device applications. In this thesis, employing polymer templates, a variety of highly ordered catalytically active transition metal nanostructures, ranging from single metallic nanoparticles of Fe, Co, Ni, Au and bimetallic nanoparticles of Ni/Fe and Co/Mo to Fe-rich silicon oxide nanodomains with uniform and tunable size and spacing have been successfully synthesized. These nanostructures have been demonstrated to be excellent catalyst systems for the synthesis of carbon nanotube and silicon nanowire. High quality, small diameter carbon nanotubes and nanowires with narrow size distribution have been successfully attained. Because these catalytically active nanostructures are uniformly distributed and do not agglomerate at the growth temperatures, uniform, high density and high quality carbon nanotube mats have been obtained. Since this polymer template approach is fully compatible with conventional top-down photolithography, lithographically selective growth of carbon nanotubes on a surface or suspended carbon nanotubes across trenches have been produced by using existing semiconductor processing. We have also shown the feasibility of producing carbon nanotubes and silicon nanowires at predefined locations on a wafer format and established a wafer-level carbon nanotube based device fabrication process. The ability of the polymer template approach to control catalyst systems at the nano-, micro- and macro-scales paves a pathway for commercialization of these 1D nanostructure-enabled devices. Beside producing well-defined, highly ordered discrete catalytically active metal-containing nanostructures by the polymer template approach, Au and Ag nanotextured surfaces have also been

  6. Fabrication and applications of copper sulfide (CuS) nanostructures

    NASA Astrophysics Data System (ADS)

    Shamraiz, Umair; Hussain, Raja Azadar; Badshah, Amin

    2016-06-01

    This review article presents different fabrication procedures (under the headlines of solvothermal routes, aerosol methods, solution methods and thermolysis), and applications (photocatalytic degradation, ablation of cancer cells, electrode material in lithium ion batteries and in gas sensing, organic solar cells, field emission properties, super capacitor applications, photoelectrochemical performance of QDSCs, photocatalytic reduction of organic pollutants, electrochemical bio sensing, enhanced PEC characteristics of pre-annealed CuS film electrodes) of copper sulfide (Covellite).

  7. Surface Enhanced Raman Spectroscopy Detection of Biomolecules Using EBL Fabricated Nanostructured Substrates

    PubMed Central

    Peters, Robert F.; Gutierrez-Rivera, Luis; Dew, Steven K.; Stepanova, Maria

    2015-01-01

    Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules is reported. The entire sequence of relevant experimental steps is described, involving the fabrication of nanostructured substrates using electron beam lithography, immobilization of biomolecules on the substrates, and their characterization utilizing surface-enhanced Raman spectroscopy (SERS). Three different designs of nano-biological systems are employed, including protein A, glucose binding protein, and a dopamine binding DNA aptamer. In the latter two cases, the binding of respective ligands, D-glucose and dopamine, is also included. The three kinds of biomolecules are immobilized on nanostructured substrates by different methods, and the results of SERS imaging are reported. The capabilities of SERS to detect vibrational modes from surface-immobilized proteins, as well as to capture the protein-ligand and aptamer-ligand binding are demonstrated. The results also illustrate the influence of the surface nanostructure geometry, biomolecules immobilization strategy, Raman activity of the molecules and presence or absence of the ligand binding on the SERS spectra acquired. PMID:25867853

  8. Fabrication of nanostructure and formation of nanocrystal for non-volatile memory.

    PubMed

    Jung, Sungwook; Parm, I O; Jang, Kyung Soo; Park, Dae-Ho; Sohn, Byeong-Hyeok; Jung, Jin Chul; Zin, Wang Cheol; Choi, Suk-Ho; Dhungel, S K; Yi, J

    2006-11-01

    In this work, we have demonstrated that the nanocrystal created by combining the self-assembled block copolymer thin film with regular semiconductor processing can be applicable to non-volatile memory device with increased charge storage capacity over planar structures. Self-assembled block copolymer thin film for nanostructures with critical dimensions below photolithographic resolution limits has been used during all experiments. Nanoporous thin film from PS-b-PMMA diblock copolymer thin film with selective removal of PMMA domains was used to fabricate nanostructure and nanocrystal. We have also reported about surface morphologies and electrical properties of the nano-needle structure formed by RIE technique. The details of nanoscale pattern of the very uniform arrays using RIE are presented. We fabricated different surface structure of nanoscale using block copolymer. We also deposited Si-rich SiNx layer using ICP-CVD on the silicon surface of nanostructure. The deposited films were studied after annealing. PL studies demonstrated nanocrystal in Si-rich SiNx film on nanostructure of silicon. PMID:17252830

  9. Fabrication of surface confined biomolecular, polymeric, and metallic nanostructures using scanning probe and electron beam lithography

    NASA Astrophysics Data System (ADS)

    Lee, Woo Kyung

    This thesis presents the fabrication and characterization of surface-confined nanostructures of biomolecules, polymer brushes, and gold nanowires on gold and silicon substrates. The molecular recognition-mediated, stepwise fabrication of patterned proteins (biotin and streptavidin) and stimulus-responsive elastin-like polypeptide (ELP) nanostructures with feature sizes on the order of 200 nm is described. Dip-pen nanolithography (DPN) of 16-mercaptohexadecanoic acid (MHA) on gold was used to build templates to tether biomolecular nanostructures. It is shown that streptavidin nanopatterns provide adapter surfaces for biotinylated proteins by molecular recognition. Nanopatterned ELPs were shown to undergo a reversible, hydrophilic-hydrophobic phase transition in response to external stimuli. Here, this phase transition behavior was studied on the molecular level by adhesion force measurements using an AFM. The strong hydrophobic interactions between ELPs were exploited to reversibly immobilize a thioredoxin-ELP fusion protein onto ELP nanopatterns above the lower critical solution temperature (LCST), demonstrating the potential for ELP nanoarrays in reusable lab-on-chip devices for protein purification or nanoscale analysis. The fabrication of surface-confined stimulus-responsive pNIPAAM brush nanopatterns in a "grafting-from" approach that combines scanning probe lithography or electron beam lithography with surface-initiated atom transfer radical polymerization (ATRP) is described. The reversible, stimulus-responsive conformational height change of nanopatterned pNIPAAM brushes was demonstrated by inverse transition cycling in water-methanol cononsolvent mixtures. The triggered control of interfacial properties on the nanometer scale holds significant promise for actuation in bionanotechnology applications where polymeric actuators may manipulate the transport, separation, and detection of biomolecules. The potentially important phenomenon of polymer brush

  10. SiGe nanostructure fabrication through selective epitaxial growth using self-assembled nanotemplates

    NASA Astrophysics Data System (ADS)

    Park, Sang-Joon; Hwang, In Chan; Lee, Heung Soon; Yeog Son, Jong; Kim, Hyungjun

    2009-11-01

    Ordered SiGe nanostructures including nanodots (NDs) and nanowires (NWs) were fabricated via selective epitaxial growth (SEG) of SiGe using ultrahigh vacuum chemical vapour deposition (UHV-CVD) on Si openings fabricated using self-assembled nanotemplates of anodic anluminum oxide (AAO) and diblock copolymer (DBC) of polystyrene-block-polymethylmethacrylate (PS-b-PMMA), exhibiting hexagonally arranged nanoholes. SiGe SEG was processed through repeating the unit cycle composed of two separated steps of SiGe growth using disilane (Si2H6) and Germane (GeH4) and chlorine (Cl2 exposure. Cl2 was used to improve the selectivity of SiGe SEG between the Si openings and the oxide area. Ordered SiGe NDs and NWs were fabricated through SiGe SEG of 20 cycles and 400 cycles on AAO/Si, respectively. In addition, ordered SiGe NDs were obtained via SiGe SEG of 20 cycles on SiO2 template, fabricated through pattern transfer of nanoholes of PS-b-PMMA to SiO2/Si. SiGe nanostructure fabrication using both AAO and PS-b-PMMA showed good replication of the nanohole size of the nanotemplates. An erratum to this article was added by the author on 18 May 2010. The text of the erratum is appended to the PDF.

  11. Photodynamic activity of nanostructured fabrics grafted with xanthene and thiazine dyes against opportunistic fungi.

    PubMed

    Kim, Joo Ran; Michielsen, Stephen

    2015-09-01

    Fungi are an important class of human pathogens for which considerable research has gone into defeating them. The photodynamic effects of rose bengal (RB), phloxine B (PB), azure A (AA), and toluidine blue O (TBO) dyes to inhibit Aspergillus fumigatus, Aspergillus niger, Trichoderma viride, Penicillium funiculosum, and Chaetomium globosum were investigated grafted to nano- and micro-structured fabrics. Three antifungal tests conducted: broth microdilution test of free dyes, zone of inhibition and quantitative antifungal assays on fabrics grafted with dyes. In the broth microdilution test, free RB displayed the lowest MIC at 32 μM to inhibit visible hyphal growth and germination but the antifungal ability of MIC for other photosensitizers below 63 μM was insignificant. RB and PB showed lower MIC than AA and TBO. In the inhibition zone tests, nanostructured fabrics grafted with RB and PB did not display fungal growth on the surface. Most microstructured fabrics grafted with AA and TBO showed little inhibition. In quantitative antifungal assay, nanostructured fabrics grafted with RB has the largest inhibition rate on T. viride and the lowest inhibition rate on P. funiculosum and the results showed the increasing inhibition rate in the order of AA < TBO < PB < RB. PMID:25972050

  12. Design and fabrication of artificial lateral line flow sensors

    NASA Astrophysics Data System (ADS)

    Fan, Zhifang; Chen, Jack; Zou, Jun; Bullen, David; Liu, Chang; Delcomyn, Fred

    2002-09-01

    Underwater flow sensing is important for many robotics and military applications, including underwater robots and vessels. We report the development of micromachined, distributed flow sensors based on a biological inspiration, the fish lateral line sensors. Design and fabrication processes for realizing individual lateral line sensor nodes are discussed in this paper, along with preliminary characterization results.

  13. Method of producing catalytic materials for fabricating nanostructures

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2013-02-19

    Methods of fabricating nano-catalysts are described. In some embodiments the nano-catalyst is formed from a powder-based substrate material and is some embodiments the nano-catalyst is formed from a solid-based substrate material. In some embodiments the substrate material may include metal, ceramic, or silicon or another metalloid. The nano-catalysts typically have metal nanoparticles disposed adjacent the surface of the substrate material. The methods typically include functionalizing the surface of the substrate material with a chelating agent, such as a chemical having dissociated carboxyl functional groups (--COO), that provides an enhanced affinity for metal ions. The functionalized substrate surface may then be exposed to a chemical solution that contains metal ions. The metal ions are then bound to the substrate material and may then be reduced, such as by a stream of gas that includes hydrogen, to form metal nanoparticles adjacent the surface of the substrate.

  14. Patterned zero-dimensional nanostructures: Fabrication and characterization

    NASA Astrophysics Data System (ADS)

    Dias, Neville Lourenco Antonio

    Due to the advantages arising from low-dimensional electronic systems, considerable effort has been put into the use of quantum dots and wires as the active media in optoelectronic devices. The realization of quantum dot based devices has been plagued with numerous obstacles. Conventional quantum dots are formed by strain-driven self-assembly. The stochastic nature of the process results in a distribution of dot sizes. If a device is composed of more than one quantum dot, the issue of uniformity becomes critical. Even if the device has only one quantum dot, uniformity is essential to obtain reproducible characteristics across multiple devices. Thus, the geometrical parameters of a quantum dot, such as shape and size as well as the chemical composition, need to be controlled. In this work, nanoscale selective area metal-organic chemical vapor deposition (MOCVD) has been used to define InAs dot nucleation sites with highly ordered dot-to-dot pitches down to 80 nm corresponding to densities greater than 10 10 cm-2, which are among the highest reported for site-defined dots. The fabrication approach avoids modification of the underlying surface, allowing for easier integration into a variety of devices. Patterning of an oxide film by electron beam lithography also allows for creation of arbitrary closely packed arrangements of quantum dots for novel device designs. The resulting quantum dot array has the potential to be used as a template for fabricating multi-stack structures for use in laser and photodetector applications. Although nano-fabrication methods impose a degree of determinism on the quantum dot size, the lack of coupling between individual dots in an array structure coupled with the size variation is the primary cause for inhomogeneous broadening in quantum dot based devices. In an attempt to address broadening in quantum dots, the nanopore active layer was proposed. The nanopore is in essence an inverse quantum dot structure consisting of a periodically

  15. Fabrication of ultra-fine nanostructures using edge transfer printing.

    PubMed

    Xue, Mianqi; Li, Fengwang; Cao, Tingbing

    2012-03-21

    The exploration of new methods and techniques for application in diverse fields, such as photonics, microfluidics, biotechnology and flexible electronics is of increasing scientific and technical interest for multiple uses over distance of 10-100 nm. This article discusses edge transfer printing--a series of unconventional methods derived from soft lithography for nanofabrication. It possesses the advantages of easy fabrication, low-cost and great serviceability. In this paper, we show how to produce exposed edges and use various materials for edge transfer printing, while nanoskiving, nanotransfer edge printing and tunable cracking for nanogaps are introduced. Besides this, different functional materials, such as metals, inorganic semiconductors and polymers, as well as localised heating and charge patterning, are described here as unconventional "inks" for printing. Edge transfer printing, which can effectively produce sub-100 nm scale ultra-fine structures, has broad applications, including metallic nanowires as nanoelectrodes, semiconductor nanowires for chemical sensors, heterostructures of organic semiconductors, plasmonic devices and so forth. PMID:22344574

  16. Hexagonal boron nitride film substrate for fabrication of nanostructures

    NASA Astrophysics Data System (ADS)

    Lee, K. S.; Kim, Y. S.; Tosa, M.; Kasahara, A.; Yosihara, K.

    2001-01-01

    The fabrication of material with an atomic scale manipulation requires the suitable advanced substrate for epitaxial growth without the effect by the substrate lattice structure. Hexagonal boron nitride (h-BN) can be the advanced substrate for atomic manipulation due to van der Waals' gap with little attractive force along to c axis. We have successfully synthesized h-BN layer on the co-deposited Cu/BN film by surface segregation phenomena using helicon wave plasma enhanced radio frequency (rf) magnetron sputtering system. Auger electron spectroscopy (AES) and X-ray photon spectroscopy (XPS) analysis showed that the h-BN composite segregated on the surface of Cu/BN film covered over 95% of the film annealed at 900 K for 30 min. Atomic forces microscopy (AFM) and scanning tunneling microscopy (STM) analysis showed that attractive force on the film surface is uniformly distributed to an extent of 2nN and that the h-BN surface can be a good electric insulator like sintered h-BN plate.

  17. New fabrication of zinc oxide nanostructure thin film gas sensors

    NASA Astrophysics Data System (ADS)

    Hendi, A. A.; Alorainy, R. H.

    2014-02-01

    The copper doped zinc oxide thin films have been prepared by sol-gel spin coating method. The structural and morphology properties of the Cu doped films were characterized by X-ray diffraction and atomic force microscope. XRD studies confirm the chemical structure of the ZnO films. The optical spectra method were used to determined optical constants and dispersion energy parameters of Cu doped Zno thin films. The optical band gap of undoped ZnO was found to be 3.16 eV. The Eg values of the films were changed with Cu doping. The refractive index dispersion of Cu doped ZnO films obeys the single oscillator model. The dispersion energy and oscillator energy values of the ZnO films were changed with Cu doping. The Cu doped ZnO nanofiber-based NH3 gas sensors were fabricated. The sensor response of the sensors was from 464.98 to 484.61 when the concentration of NH3 is changed 6600-13,300 ppm. The obtained results indicate that the response of the ZnO film based ammonia gas sensors can be controlled by copper content.

  18. Fabrication and deformation of three-dimensional hollow ceramic nanostructures

    NASA Astrophysics Data System (ADS)

    Jang, Dongchan; Meza, Lucas R.; Greer, Frank; Greer, Julia R.

    2013-10-01

    Creating lightweight, mechanically robust materials has long been an engineering pursuit. Many siliceous skeleton species—such as diatoms, sea sponges and radiolarians—have remarkably high strengths when compared with man-made materials of the same composition, yet are able to remain lightweight and porous. It has been suggested that these properties arise from the hierarchical arrangement of different structural elements at their relevant length scales. Here, we report the fabrication of hollow ceramic scaffolds that mimic the length scales and hierarchy of biological materials. The constituent solids attain tensile strengths of 1.75 GPa without failure even after multiple deformation cycles, as revealed by in situ nanomechanical experiments and finite-element analysis. We discuss the high strength and lack of failure in terms of stress concentrators at surface imperfections and of local stresses within the microstructural landscape. Our findings suggest that the hierarchical design principles offered by hard biological organisms can be applied to create damage-tolerant lightweight engineering materials.

  19. Characterization of Ag nanostructures fabricated by laser-induced dewetting of thin films

    NASA Astrophysics Data System (ADS)

    Nikov, Ru. G.; Nedyalkov, N. N.; Atanasov, P. A.; Hirsch, D.; Rauschenbach, B.; Grochowska, K.; Sliwinski, G.

    2016-06-01

    The paper presents results on laser nanostructuring of Ag thin films. The thin films are deposited on glass substrates by pulsed laser deposition technology. The as fabricated films are then annealed by nanosecond laser pulses delivered by Nd:YAG laser system operated at λ = 355 nm. The film modification is studied as a function of the film thickness and the parameters of the laser irradiation as pulse number and laser fluence. In order to estimate the influence of the environment on the characteristics of the fabricated structures the Ag films are annealed in different surrounding media: water, air and vacuum. It is found that at certain conditions the laser treatment may lead to decomposition of the films into a monolayer of nanoparticles with narrow size distribution. The optical properties of the fabricated nanostructures are investigated on the basis of transmission spectra taken by optical spectrometer. In the measured spectra plasmon resonance band is observed as its shape and position vary depending on the processing conditions. The fabricated structures are covered with Rhodamine 6G and tested as active substrates for Surface Enhanced Raman Spectroscopy (SERS).

  20. Fabrication of nanochannels with ladder nanostructure at the bottom using AFM nanoscratching method.

    PubMed

    Yan, Yongda; Geng, Yanquan; Hu, Zhenjiang; Zhao, Xuesen; Yu, Bowen; Zhang, Qi

    2014-01-01

    This letter presents a novel atomic force microscopy (AFM)-based nanomanufacturing method combining the tip scanning with the high-precision stage movement to fabricate nanochannels with ladder nanostructure at the bottom by continuous scanning with a fixed scan size. Different structures can be obtained according to the matching relation of the tip feeding velocity and the precision stage moving velocity. This relationship was first studied in detail to achieve nanochannels with different ladder nanostructures at the bottom. Machining experiments were then performed to fabricate nanochannels on an aluminum alloy surface to demonstrate the capability of this AFM-based fabrication method presented in this study. Results show that the feed value and the tip orientation in the removing action play important roles in this method which has a significant effect on the machined surfaces. Finally, the capacity of this method to fabricate a large-scale nanochannel was also demonstrated. This method has the potential to advance the existing AFM tip-based nanomanufacturing technique of the formation these complex structures by increasing the removal speed, simplifying the processing procedure and achieving the large-scale nanofabrication. PMID:24940171

  1. Fabrication of nanochannels with ladder nanostructure at the bottom using AFM nanoscratching method

    PubMed Central

    2014-01-01

    This letter presents a novel atomic force microscopy (AFM)-based nanomanufacturing method combining the tip scanning with the high-precision stage movement to fabricate nanochannels with ladder nanostructure at the bottom by continuous scanning with a fixed scan size. Different structures can be obtained according to the matching relation of the tip feeding velocity and the precision stage moving velocity. This relationship was first studied in detail to achieve nanochannels with different ladder nanostructures at the bottom. Machining experiments were then performed to fabricate nanochannels on an aluminum alloy surface to demonstrate the capability of this AFM-based fabrication method presented in this study. Results show that the feed value and the tip orientation in the removing action play important roles in this method which has a significant effect on the machined surfaces. Finally, the capacity of this method to fabricate a large-scale nanochannel was also demonstrated. This method has the potential to advance the existing AFM tip-based nanomanufacturing technique of the formation these complex structures by increasing the removal speed, simplifying the processing procedure and achieving the large-scale nanofabrication. PMID:24940171

  2. TiO2 hierarchical nanostructures: Hydrothermal fabrication and application in dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Liang, Jia; Zhang, Gengmin; Yang, Jin; Sun, Wentao; Shi, Mingji

    2015-01-01

    Arrays of TiO2 hierarchical nanostructures that consisted of rutile nanorods and anatase branches were hydrothermally fabricated and employed as photoanodes in dye-sensitized solar cells (DSSCs). Each hierarchical nanostructure array was attained in two steps. First, a primary nanorod array was synthesized in aqueous solutions of hydrochloric acid (HCl) and tetrabutyl titanate (C16H36O4Ti); subsequently, secondary branches were grown on the nanorods in aqueous solutions of ammonium hexafluorotitanate ((NH4)2TiF6) and boric acid (H3BO3). The secondary anatase branches filled part of the space among the primary rutile nanorods and gave rise to a larger surface area. Light-harvesting capability of the DSSCs with TiO2 hierarchical nanostructures as photoanodes was appreciably improved because more dye molecules could be loaded on the photoanodes and more light could be scattered inside the DSSCs. Therefore, the conversion efficiencies of the DSSCs were doubled by replacing the photoanode of primary TiO2 nanorod array with the photoanodes of TiO2 hierarchical nanostructure arrays. Furthermore, in order to reach a compromise between the photoanode surface area and the inter-nanorod space volume, the growth time of the secondary TiO2 anatase branches was optimized.

  3. Fabrication of nanostructure by physical vapor deposition with glancing angle deposition technique and its applications

    NASA Astrophysics Data System (ADS)

    Horprathum, M.; Eiamchai, P.; Kaewkhao, J.; Chananonnawathorn, C.; Patthanasettakul, V.; Limwichean, S.; Nuntawong, N.; Chindaudom, P.

    2014-09-01

    A nanostructural thin film is one of the highly exploiting research areas particularly in applications in sensor, photocatalytic, and solar-cell technologies. In the past two decades, the integration of glancing-angle deposition (GLAD) technique to physical vapor deposition (PVD) process has gained significant attention for well-controlled multidimensional nanomorphologies because of fast, simple, cost-effective, and mass-production capability. The performance and functional properties of the coated thin films generally depend upon their nanostructural compositions, i.e., large aspect ratio, controllable porosity, and shape. Such structural platforms make the fabricated thin films very practical for several realistic applications. We therefore present morphological and nanostructural properties of various deposited materials, which included metals, i.e., silver (Ag), and oxide compounds, i.e., tungsten oxide (WO3), titanium dioxide (TiO2), and indium tin oxide (ITO). Different PVD techniques based on DC magnetron sputtering and electron-beam evaporation, both with the integrated GLAD component, were discussed. We further explore engineered nanostructures which enable controls of optical, electrical, and mechanical properties. These improvements led to several practical applications in surface-enhanced Raman, smart windows, gas sensors, self-cleaning materials and transparent conductive oxides (TCO).

  4. Fabrication of nanostructure by physical vapor deposition with glancing angle deposition technique and its applications

    SciTech Connect

    Horprathum, M. Eiamchai, P. Patthanasettakul, V.; Limwichean, S.; Nuntawong, N.; Chindaudom, P.; Kaewkhao, J.; Chananonnawathorn, C.

    2014-09-25

    A nanostructural thin film is one of the highly exploiting research areas particularly in applications in sensor, photocatalytic, and solar-cell technologies. In the past two decades, the integration of glancing-angle deposition (GLAD) technique to physical vapor deposition (PVD) process has gained significant attention for well-controlled multidimensional nanomorphologies because of fast, simple, cost-effective, and mass-production capability. The performance and functional properties of the coated thin films generally depend upon their nanostructural compositions, i.e., large aspect ratio, controllable porosity, and shape. Such structural platforms make the fabricated thin films very practical for several realistic applications. We therefore present morphological and nanostructural properties of various deposited materials, which included metals, i.e., silver (Ag), and oxide compounds, i.e., tungsten oxide (WO{sub 3}), titanium dioxide (TiO{sub 2}), and indium tin oxide (ITO). Different PVD techniques based on DC magnetron sputtering and electron-beam evaporation, both with the integrated GLAD component, were discussed. We further explore engineered nanostructures which enable controls of optical, electrical, and mechanical properties. These improvements led to several practical applications in surface-enhanced Raman, smart windows, gas sensors, self-cleaning materials and transparent conductive oxides (TCO)

  5. Extreme wettability of nanostructured glass fabricated by non-lithographic, anisotropic etching

    NASA Astrophysics Data System (ADS)

    Yu, Eusun; Kim, Seul-Cham; Lee, Heon Ju; Oh, Kyu Hwan; Moon, Myoung-Woon

    2015-03-01

    Functional glass surfaces with the properties of superhydrophobicity/or superhydrohydrophilicity, anti-condensation or low reflectance require nano- or micro-scale roughness, which is difficult to fabricate directly on glass surfaces. Here, we report a novel non-lithographic method for the fabrication of nanostructures on glass; this method introduces a sacrificial SiO2 layer for anisotropic plasma etching. The first step was to form nanopillars on SiO2 layer-coated glass by using preferential CF4 plasma etching. With continuous plasma etching, the SiO2 pillars become etch-resistant masks on the glass; thus, the glass regions covered by the SiO2 pillars are etched slowly, and the regions with no SiO2 pillars are etched rapidly, resulting in nanopatterned glass. The glass surface that is etched with CF4 plasma becomes superhydrophilic because of its high surface energy, as well as its nano-scale roughness and high aspect ratio. Upon applying a subsequent hydrophobic coating to the nanostructured glass, a superhydrophobic surface was achieved. The light transmission of the glass was relatively unaffected by the nanostructures, whereas the reflectance was significantly reduced by the increase in nanopattern roughness on the glass.

  6. Extreme wettability of nanostructured glass fabricated by non-lithographic, anisotropic etching.

    PubMed

    Yu, Eusun; Kim, Seul-Cham; Lee, Heon Ju; Oh, Kyu Hwan; Moon, Myoung-Woon

    2015-01-01

    Functional glass surfaces with the properties of superhydrophobicity/or superhydrohydrophilicity, anti-condensation or low reflectance require nano- or micro-scale roughness, which is difficult to fabricate directly on glass surfaces. Here, we report a novel non-lithographic method for the fabrication of nanostructures on glass; this method introduces a sacrificial SiO2 layer for anisotropic plasma etching. The first step was to form nanopillars on SiO2 layer-coated glass by using preferential CF4 plasma etching. With continuous plasma etching, the SiO2 pillars become etch-resistant masks on the glass; thus, the glass regions covered by the SiO2 pillars are etched slowly, and the regions with no SiO2 pillars are etched rapidly, resulting in nanopatterned glass. The glass surface that is etched with CF4 plasma becomes superhydrophilic because of its high surface energy, as well as its nano-scale roughness and high aspect ratio. Upon applying a subsequent hydrophobic coating to the nanostructured glass, a superhydrophobic surface was achieved. The light transmission of the glass was relatively unaffected by the nanostructures, whereas the reflectance was significantly reduced by the increase in nanopattern roughness on the glass. PMID:25791414

  7. Fabrication of large-area arrays of hybrid nanostructures on polymer-derived chemically patterned surfaces

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoying; Nepal, Dhriti; Biswas, Sushmita; Park, Kyoungweon; Vaia, Richard; Nealey, Paul; Air Force Research Laboratories Collaboration; University of Chicago Team

    2014-03-01

    The precise placement and assembly of nanoparticles (NPs) into large-area nanostructure arrays will allow for the design and implementation of advanced nanoscale devices for applications in fields such as quantum computing, optical sensing, superlenses, photocatalysis, photovoltaics, and non-linear optics. Our work is focused on using chemically nanopatterned surfaces to fabricate arrays of hybrid nanostructures with each component of the building block at well-defined positions. The precise chemical contrast patterns with densities and resolution of features created using standard tools of lithography, polymer self-assembly, and surface functionalization allow for control of position and interparticle spacing through selective surface-particle and particle-particle interactions. We have demonstrated the assembly of NPs, including metallic NPs and semiconductor quantum dots, into arrays of hybrid structures with various geometries, such as monomers, dimers, quatrefoils, stripes, and chains. We have developed protocols to fabricate NP arrays over a variety of substrates, which allows for the design and characterization of optical and electronic nanostructures and devices to meet the requirements of various technological applications.

  8. Extreme wettability of nanostructured glass fabricated by non-lithographic, anisotropic etching

    PubMed Central

    Yu, Eusun; Kim, Seul-Cham; Lee, Heon Ju; Oh, Kyu Hwan; Moon, Myoung-Woon

    2015-01-01

    Functional glass surfaces with the properties of superhydrophobicity/or superhydrohydrophilicity, anti-condensation or low reflectance require nano- or micro-scale roughness, which is difficult to fabricate directly on glass surfaces. Here, we report a novel non-lithographic method for the fabrication of nanostructures on glass; this method introduces a sacrificial SiO2 layer for anisotropic plasma etching. The first step was to form nanopillars on SiO2 layer-coated glass by using preferential CF4 plasma etching. With continuous plasma etching, the SiO2 pillars become etch-resistant masks on the glass; thus, the glass regions covered by the SiO2 pillars are etched slowly, and the regions with no SiO2 pillars are etched rapidly, resulting in nanopatterned glass. The glass surface that is etched with CF4 plasma becomes superhydrophilic because of its high surface energy, as well as its nano-scale roughness and high aspect ratio. Upon applying a subsequent hydrophobic coating to the nanostructured glass, a superhydrophobic surface was achieved. The light transmission of the glass was relatively unaffected by the nanostructures, whereas the reflectance was significantly reduced by the increase in nanopattern roughness on the glass. PMID:25791414

  9. Use of thin sectioning (nanoskiving) to fabricate nanostructures for electronic and optical applications.

    PubMed

    Lipomi, Darren J; Martinez, Ramses V; Whitesides, George M

    2011-09-01

    This Review discusses nanoskiving--a simple and inexpensive method of nanofabrication, which minimizes requirements for access to cleanrooms and associated facilities, and which makes it possible to fabricate nanostructures from materials, and of geometries, to which more familiar methods of nanofabrication are not applicable. Nanoskiving requires three steps: 1) deposition of a metallic, semiconducting, ceramic, or polymeric thin film onto an epoxy substrate; 2) embedding this film in epoxy, to form an epoxy block, with the film as an inclusion; and 3) sectioning the epoxy block into slabs with an ultramicrotome. These slabs, which can be 30 nm-10 μm thick, contain nanostructures whose lateral dimensions are equal to the thicknesses of the embedded thin films. Electronic applications of structures produced by this method include nanoelectrodes for electrochemistry, chemoresistive nanowires, and heterostructures of organic semiconductors. Optical applications include surface plasmon resonators, plasmonic waveguides, and frequency-selective surfaces. PMID:21755580

  10. The fabrication of subwavelength anti-reflective nanostructures using a bio-template

    NASA Astrophysics Data System (ADS)

    Xie, Guoyong; Zhang, Guoming; Lin, Feng; Zhang, Jin; Liu, Zhongfan; Mu, Shichen

    2008-03-01

    This paper describes a paradigm, a simple, low-cost and conventional approach to the fabrication of large-area subwavelength anti-reflective nanostructures on films directly with a bio-template. Specifically, the nano-nipple arrays on the surface of cicada wings have been precisely replicated to a PMMA (polymethyl methacrylate) film with high reproducibility by a technique of replica molding, which mainly involves two processes: one is that a negative Au mold is prepared directly from the bio-template of the cicada wing by thermal deposition; the other is that the Au mold is used to obtain the replica of the nanostructures on the original cicada wing by casting polymer. The reflectance spectra measurement shows that the replicated PMMA film can considerably reduce reflectivity at its surface over a large wavelength range from 250 to 800 nm, indicating that the anti-reflective property has also been inherited by the PMMA film.

  11. Nano-structure fabrication by using self-organizing properties of materials

    SciTech Connect

    Hayashi, T.; Maruno, T.; Ishii, Y.

    1994-12-31

    Self-organizing properties of materials can be used to fabricate well-ordered nanostructures on a large scale and also to develop new advanced materials. Three examples of self-organized nanostructures are described in this paper. A unidirectionally ordered metallo-phthalocyanine thin film was formed over the entire surface of a sapphire (1{bar 1}02) substrate by using a newly synthesized dibenzo[b,t] phthalocyaninato-Zn(II), which has a unique two-fold symmetrical molecular structure. A buried SiO{sub 2} layer with atomically abrupt Si/SiO{sub 2} interface was formed by oxygen ion implantation into silicon and subsequent annealing. A nano-particle consisting of outer graphitic shells and a core nano-crystal of LaC{sub 2} was formed in a self-organizing manner when a hot carbon-lanthanum particle was cooled on an arc-discharge electrode in a He atmosphere.

  12. MATERIALS, FABRICATION, AND MANUFACTURING OF MICRO/NANOSTRUCTURED SURFACES FOR PHASE-CHANGE HEAT TRANSFER ENHANCEMENT

    SciTech Connect

    McCarthy, M; Gerasopoulos, K; Maroo, SC; Hart, AJ

    2014-07-23

    This article describes the most prominent materials, fabrication methods, and manufacturing schemes for micro- and nanostructured surfaces that can be employed to enhance phase-change heat transfer phenomena. The numerous processes include traditional microfabrication techniques such as thin-film deposition, lithography, and etching, as well as template-assisted and template-free nanofabrication techniques. The creation of complex, hierarchical, and heterogeneous surface structures using advanced techniques is also reviewed. Additionally, research needs in the field and future directions necessary to translate these approaches from the laboratory to high-performance applications are identified. Particular focus is placed on the extension of these techniques to the design of micro/nanostructures for increased performance, manufacturability, and reliability. The current research needs and goals are detailed, and potential pathways forward are suggested.

  13. Fabrication of Pillar Shaped Electrode Arrays for Artificial Retinal Implants

    PubMed Central

    Kim, Eui Tae; Seo, Jong-Mo; Woo, Se Joon; Zhou, Jing Ai; Chung, Hum; Kim, Sung June

    2008-01-01

    Polyimide has been widely applied to neural prosthetic devices, such as the retinal implants, due to its well-known biocompatibility and ability to be micropatterned. However, planar films of polyimide that are typically employed show a limited ability in reducing the distance between electrodes and targeting cell layers, which limits site resolution for effective multi-channel stimulation. In this paper, we report a newly designed device with a pillar structure that more effectively interfaces with the target. Electrode arrays were successfully fabricated and safely implanted inside the rabbit eye in suprachoroidal space. Optical Coherence Tomography (OCT) showed well-preserved pillar structures of the electrode without damage. Bipolar stimulation was applied through paired sites (6:1) and the neural responses were successfully recorded from several regions in the visual cortex. Electrically evoked cortical potential by the pillar electrode array stimulation were compared to visual evoked potential under full-field light stimulation.

  14. Bio-inspired piezoelectric artificial hair cell sensor fabricated by powder injection molding

    NASA Astrophysics Data System (ADS)

    Han, Jun Sae; Oh, Keun Ha; Moon, Won Kyu; Kim, Kyungseop; Joh, Cheeyoung; Seo, Hee Seon; Bollina, Ravi; Park, Seong Jin

    2015-12-01

    A piezoelectric artificial hair cell sensor was fabricated by the powder injection molding process in order to make an acoustic vector hydrophone. The entire process of powder injection molding was developed and optimized for PMN-PZT ceramic powder. The artificial hair cell sensor, which consists of high aspect ratio hair cell and three rectangular mechanoreceptors, was precisely fabricated through the developed powder injection molding process. The density and the dielectric property of the fabricated sensor shows 98% of the theoretical density and 85% of reference dielectric property of PMN-PZT ceramic powder. With regard to homogeneity, three rectangular mechanoreceptors have the same dimensions, with 3 μm of tolerance with 8% of deviation of dielectric property. Packaged vector hydrophones measure the underwater acoustic signals from 500 to 800 Hz with -212 dB of sensitivity. Directivity of vector hydrophone was acquired at 600 Hz as analyzing phase differences of electric signals.

  15. Large-scale controlled fabrication of highly roughened flower-like silver nanostructures in liquid crystalline phase

    PubMed Central

    Yang, Chengliang; Xiang, Xiangjun; Zhang, Ying; Peng, Zenghui; Cao, Zhaoliang; Wang, Junlin; Xuan, Li

    2015-01-01

    Large-scale controllable fabrication of highly roughened flower-like silver nanostructures is demonstrated experimentally via electrodeposition in the liquid crystalline phase. Different sizes of silver flowers are fabricated by adjusting the deposition time and the concentration of the silver nitrate solution. The density of the silver flowers in the sample is also controllable in this work. The flower-like silver nanostructures can serve as effective surface-enhanced Raman scattering and surface-enhanced fluorescence substrates because of their local surface plasmon resonance, and they may have applications in photoluminescence and catalysis. This liquid crystalline phase is used as a soft template for fabricating flower-like silver nanostructures for the first time, and this approach is suitable for large-scale uniform fabrication up to several centimetres. PMID:26216669

  16. Fabrication and measurement of nanostructures on the micro ball surface using a modified atomic force microscope.

    PubMed

    Zhao, X S; Geng, Y Q; Li, W B; Yan, Y D; Hu, Z J; Sun, T; Liang, Y C; Dong, S

    2012-11-01

    In order to machine and measure nanostructures on the micro ball surface, a modified atomic force microscope (AFM) combining a commercial AFM system with a home built precision air bearing spindle is established. Based on this system, motions of both the AFM scanner and the air bearing spindle are controlled to machine nanostructures on the micro ball based on the AFM tip-based nano mechanical machining approach. The eccentric error between the axis of the micro ball and the axis of the spindle is reduced to 3-4 μm by the provided fine adjusting method. A 1000 nano lines array, 36 square pits structure, 10 square pits structure, and a zig-zag structure on the circumference of the micro ball with the diameter of 1.5 mm are machined successfully. The measurement results achieved by the same system reveal that the profiles and mode-power spectra curves of the micro ball are influenced by the artificially machined nanostructures significantly according to their distributions. This work is an useful attempt for modifying the micro ball profile and manufacture of the spherical modulation targets to study the experimental performance of the micro ball in implosion. PMID:23206095

  17. Three-dimensional fabrication of metallic micro/nanostructures by two-photon polymerization for metamaterials

    NASA Astrophysics Data System (ADS)

    Formanek, Florian; Takeyasu, Nobuyuki; Tanaka, Takuo; Chiyoda, Kenta; Ishikawa, Atsushi; Kawata, Satoshi

    2006-08-01

    We report on selective metal deposition over complex polymer structures formed by two-photon induced photopolymerization (TPP) technique. Periodic three-dimensional (3D) polymer micro/nanostructures are fabricated by means of a microlens array to produce multiple spots from a single-beam femtosecond laser amplified by a regenerative amplifier. The photopolymerizable resin and the glass substrate are chemically modified, and a pre-treatment with SnCl2 is applied before realizing a uniform silver coating by electroless plating. This preparation enables a selective deposition of small silver particles only on the polymer surface all over the sample and to avoid metal deposition on the substrate. Electrical measurements show the structures to be highly conductive with typical resistivities ρ approx. 10 -7 Ωm, only a few times larger than the value for bulk silver. By taking advantage of the high accuracy and arbitrary shape modeling of TPP fabrication, we can realize complex periodic and/or metallic micro-nanostructures which were so far out of reach. Thus, a straightforward application could be the realization of metamaterials. The processing efficiency of our technique is demonstrated with the fabrication of several large samples, created by more than 700 objects written in parallel and metallized with silver.

  18. Fabrication of superconducting MgB2 nanostructures by an electron beam lithography-based technique

    NASA Astrophysics Data System (ADS)

    Portesi, C.; Borini, S.; Amato, G.; Monticone, E.

    2006-03-01

    In this work, we present the results obtained in fabrication and characterization of magnesium diboride nanowires realized by an electron beam lithography (EBL)-based method. For fabricating MgB2 thin films, an all in situ technique has been used, based on the coevaporation of B and Mg by means of an e-gun and a resistive heater, respectively. Since the high temperatures required for the fabrication of good quality MgB2 thin films do not allow the nanostructuring approach based on the lift-off technique, we structured the samples combining EBL, optical lithography, and Ar milling. In this way, reproducible nanowires 1 μm long have been obtained. To illustrate the impact of the MgB2 film processing on its superconducting properties, we measured the temperature dependence of the resistance on a nanowire and compared it to the original magnesium diboride film. The electrical properties of the films are not degraded as a consequence of the nanostructuring process, so that superconducting nanodevices may be obtained by this method.

  19. Ru nanostructure fabrication using an anodic aluminum oxide nanotemplate and highly conformal Ru atomic layer deposition.

    PubMed

    Kim, Woo-Hee; Park, Sang-Joon; Son, Jong-Yeog; Kim, Hyungjun

    2008-01-30

    We fabricated metallic nanostructures directly on Si substrates through a hybrid nanoprocess combining atomic layer deposition (ALD) and a self-assembled anodic aluminum oxide (AAO) nanotemplate. ALD Ru films with Ru(DMPD)(EtCp) as a precursor and O(2) as a reactant exhibited high purity and low resistivity with negligible nucleation delay and low roughness. These good growth characteristics resulted in the excellent conformality for nanometer-scale vias and trenches. Additionally, AAO nanotemplates were fabricated directly on Si and Ti/Si substrates through a multiple anodization process. AAO nanotemplates with various hole sizes (30-100 nm) and aspect ratios (2:1-20:1) were fabricated by controlling the anodizing process parameters. The barrier layers between AAO nanotemplates and Si substrates were completely removed by reactive ion etching (RIE) using BCl(3) plasma. By combining the ALD Ru and the AAO nanotemplate, Ru nanostructures with controllable sizes and shapes were prepared on Si and Ti/Si substrates. The Ru nanowire array devices as a platform for sensor devices exhibited befitting properties of good ohmic contact and high surface/volume ratio. PMID:21817499

  20. A rechargeable Na-Zn hybrid aqueous battery fabricated with nickel hexacyanoferrate and nanostructured zinc

    NASA Astrophysics Data System (ADS)

    Lu, Ke; Song, Bin; Zhang, Jintao; Ma, Houyi

    2016-07-01

    Rechargeable aqueous batteries are very attractive as a promising alternative energy storage system, although their reversible capacity is typically limited. A new rechargeable Na-Zn hybrid aqueous battery with nickel hexacyanoferrate (NiHCF) cathode and the nanostructured zinc anode is fabricated. The rational combination of two materials with mild aqueous electrolyte renders the devices with an average operating voltage close to 1.5 V, higher specific capacity of 76.2 mAh g-1, and a good cycling stability with 81% capacity retention for 1000 cycles. These remarkable features can provide guidance for the development of rechargeable batteries from the naturally abundant electrode materials with neutral aqueous electrolytes.

  1. The fabrication of 3-D nanostructures by a low- voltage EBL

    NASA Astrophysics Data System (ADS)

    Oh, Seung Hun; Kim, Jae Gu; Kim, Chang Seok; Choi, Doo Sun; Chang, Sunghwan; Jeong, Myung Yung

    2011-02-01

    Three-dimensional (3-D) structures are used in many applications, including the fabrication of opto-electronic and bio-MEMS devices. Among the various fabrication techniques available for 3-D structures, nano imprint lithography (NIL) is preferred for producing nanoscale 3-D patterns because of its simplicity, relatively short processing time, and high manufacturing precision. For efficient replication in NIL, a precise 3-D stamp must be used as an imprinting tool. Hence, we attempted the fabrication of original 3-D master molds by low-voltage electron beam lithography (EBL). We then fabricated polydimethylsiloxane (PDMS) stamps from the original 3-D mold via replica molding with ultrasonic vibration.First, we experimentally analyzed the characteristics of low-voltage EBL in terms of various parameters such as resist thickness, acceleration voltage, aperture size, and baking temperature. From these e-beam exposure experiments, we found that the exposure depth and width were almost saturated at 3 kV or lesser, even when the electron dosage was increased. This allowed for the fabrication of various stepped 3-D nanostructures at a low voltage. In addition, by using line-dose EBL, V-groove patterns could be fabricated on a cured electron resist (ER) at a low voltage and low baking temperature. Finally, the depth variation could be controlled to within 10 nm through superposition exposure at 1 kV. From these results, we determined the optimum electron beam exposure conditions for the fabrication of various 3-D structures on ERs by low-voltage EBL. We then fabricated PDMS stamps via the replica molding process.

  2. Nanostructured grating patterns over a large area fabricated by optically directed assembly.

    PubMed

    Huang, Xiaoping; Chen, Kai; Qi, Mingxi; Li, Yu; Hou, Yumeng; Wang, Ying; Zhao, Qing; Luo, Xiangang; Xu, Qingyu

    2016-07-21

    Optical trapping and manipulation of nanoparticles (NPs) have been widely used in nanotechnology and biology. Here, we demonstrate an optically directed assembly (ODA) route for bottom-up fabrication of stable nanostructured grating patterns in solution using laser standing evanescent wave (LSEW) fields. The control mechanism is the intriguing cooperative action of the periodically line-centered attractive optical gradient force and the near field dipolar coupling force induced by LSEW, which leads to assembly of the colloidal silver NPs into robust grating patterns within minutes. The anisotropic polarization nature of the grating patterns was studied further by examining the morphology correlation of the surface-enhanced Raman scattering (SERS)-based signal amplification. We show the LSEW ODA method can optimize and stabilize the strongest dipolar coupling style among the NPs during pattern assembly. These results advance the further understanding of ODA of colloid NPs and might have many potential applications in SERS, catalysis, nanophotonics and nano-fabrication. PMID:27341650

  3. Cluster ion beam assisted fabrication of metallic nanostructures for plasmonic applications

    NASA Astrophysics Data System (ADS)

    Saleem, Iram; Tilakaratne, Buddhi P.; Li, Yang; Bao, Jiming; Wijesundera, Dharshana N.; Chu, Wei-Kan

    2016-08-01

    We report a high-throughput, single-step method for fabricating rippled plasmonic nanostructure arrays via self-assembly induced by oblique angle cluster ion beam irradiation of metal surfaces. This approach does not require lithographic or chemical processes and has the prominent advantage of possible large surface area coverage and applicability to different starting materials. The polarization dependent plasmonic property of the gold nano-ripple is due to their one dimension structure. The localized plasmon resonance frequency of synthesized nano-ripple arrays is tunable by changing nano-ripple dimensions that can be engineered by changing the cluster ion beam irradiation parameters. In this specific case presented, using 30 keV Ar-gas cluster ion beam, we fabricate gold nano-ripple arrays that show localized plasmon resonance in the visible range through near IR range, tunable by varying cluster ion irradiation fluence.

  4. Production of Engineered Fabrics Using Artificial Neural Network-Genetic Algorithm Hybrid Model

    NASA Astrophysics Data System (ADS)

    Mitra, Ashis; Majumdar, Prabal Kumar; Banerjee, Debamalya

    2015-10-01

    The process of fabric engineering which is generally practised in most of the textile mills is very complicated, repetitive, tedious and time consuming. To eliminate this trial and error approach, a new approach of fabric engineering has been attempted in this work. Data sets of construction parameters [comprising of ends per inch, picks per inch, warp count and weft count] and three fabric properties (namely drape coefficient, air permeability and thermal resistance) of 25 handloom cotton fabrics have been used. The weights and biases of three artificial neural network (ANN) models developed for the prediction of drape coefficient, air permeability and thermal resistance were used to formulate the fitness or objective function and constraints of the optimization problem. The optimization problem was solved using genetic algorithm (GA). In both the fabrics which were attempted for engineering, the target and simulated fabric properties were very close. The GA was able to search the optimum set of fabric construction parameters with reasonably good accuracy except in case of EPI. However, the overall result is encouraging and can be improved further by using larger data sets of handloom fabrics by hybrid ANN-GA model.

  5. Templated fabrication of periodic arrays of metallic and silicon nanorings with complex nanostructures

    NASA Astrophysics Data System (ADS)

    Liu, Xuefeng; Gozubenli, Numan; Choi, Baeck; Jiang, Peng; Meagher, Timothy; Jiang, Bin

    2015-02-01

    Here we report a scalable colloidal templating approach for fabricating periodic arrays of metallic and silicon nanorings with complex nanostructures. Non-close-packed monolayer silica colloidal crystal prepared by a simple spin-coating technology is first used as template for making periodic arrays of mushroom-like composite nanostructures consisting of silica spherical caps and polymer stems. Subsequent metal sputtering and reactive ion etching lead to the formation of ordered asymmetric nickel nanorings which can be further utilized as etching masks for patterning periodic arrays of symmetric silicon nanorings. Moreover, periodic arrays of metallic and silicon concentric double nanorings can be fabricated by using the asymmetric nickel nanorings as templates. We have also demonstrated that gold concentric double nanorings show strong surface-enhanced Raman scattering (SERS) with a SERS enhancement factor of ˜9.5 × 107 from adsorbed benzenethiol molecules. The SERS enhancement and the electric field amplitude distribution surrounding gold concentric double nanorings have been calculated by using finite element electromagnetic modeling. This new colloidal templating technique is compatible with standard microfabrication and enables wafer-scale production of a variety of periodic nanorings with hierarchical structures that could find important technological applications in plasmonic and magnetic devices.

  6. Surface-enhanced Raman scattering substrates fabricated using electroless plating on polymer-templated nanostructures.

    PubMed

    Bantz, Kyle C; Haynes, Christy L

    2008-06-01

    Surface-enhanced Raman scattering (SERS) has great potential as an analytical technique based on the unique molecular signatures presented even by structurally similar analyte species and the minimal interference of scattering from water when sampling in aqueous environments. Unfortunately, analytical SERS applications have been restricted on the basis of limitations in substrate design. Herein, we present a simple SERS substrate that exploits electroless deposition onto a nanoparticle-seeded polymer scaffold that can be fabricated quickly and without specialized equipment. The polymer-templated nanostructures have stable enhancement factors that are comparable to the traditional silver film over nanospheres (AgFON) substrate, broad localized surface plasmon resonance spectra that allow various Raman excitation wavelengths to be utilized, and tolerance for both aqueous and organic environments, even after 5 day exposure. These polymer-templated nanostructures have an advantage over the AgFON substrate based on the ease of fabrication; specifically, the ability to generate fresh SERS substrates outside the laboratory environment will facilitate the application of SERS to new analytical spectroscopy applications. PMID:18461977

  7. Fabrication of solution processed 3D nanostructured CuInGaS₂ thin film solar cells.

    PubMed

    Chu, Van Ben; Cho, Jin Woo; Park, Se Jin; Hwang, Yun Jeong; Park, Hoo Keun; Do, Young Rag; Min, Byoung Koun

    2014-03-28

    In this study we demonstrate the fabrication of CuInGaS₂ (CIGS) thin film solar cells with a three-dimensional (3D) nanostructure based on indium tin oxide (ITO) nanorod films and precursor solutions (Cu, In and Ga nitrates in alcohol). To obtain solution processed 3D nanostructured CIGS thin film solar cells, two different precursor solutions were applied to complete gap filling in ITO nanorods and achieve the desirable absorber film thickness. Specifically, a coating of precursor solution without polymer binder material was first applied to fill the gap between ITO nanorods followed by deposition of the second precursor solution in the presence of a binder to generate an absorber film thickness of ∼1.3 μm. A solar cell device with a (Al, Ni)/AZO/i-ZnO/CdS/CIGS/ITO nanorod/glass structure was constructed using the CIGS film, and the highest power conversion efficiency was measured to be ∼6.3% at standard irradiation conditions, which was 22.5% higher than the planar type of CIGS solar cell on ITO substrate fabricated using the same precursor solutions. PMID:24569126

  8. On-chip Fabrication of High Performance Nanostructured ZnO UV Detectors

    PubMed Central

    Alenezi, Mohammad R.; Henley, Simon J.; Silva, S. R. P.

    2015-01-01

    Developing rationally controlled bottom-up device fabrication processes is essential for the achievement of high performance optimal devices. We report a controlled, seedless and site-selective hydrothermal technique to fabricate high-performance nanostructured ZnO UV-detectors directly on-chip. We demonstrate that by controlling the nanowire growth process, via tuning the experimental parameters such as the concentration of reactants and the growth time, and by introducing a refresh of the growth solution, the device structure efficiency can be enhanced to significantly improve its performance. The on-chip fabricated bridging nanosyringe ultraviolet detector demonstrates improved sensitivity (~105), nanowatts detectability, and ultrafast response-time (90 ms) and recovery-time (210 ms). The improvement in response-time and recovery-time is attributed to the unique nanowire-nanowire junction barrier dominated resistance and the direct contact between ZnO and Au electrodes. Furthermore, the enhanced sensitivity and nanowatts detectability of the bridging nanosyringe device are due to the reduction in dimensionality and ultrahigh surface-to-volume ratio. This work paves the way toward low cost, large scale, low temperature, seedless and site-selective fabrication of high performance ZnO nanowire sensors on flexible and transparent substrates. PMID:25687120

  9. On-chip Fabrication of High Performance Nanostructured ZnO UV Detectors

    NASA Astrophysics Data System (ADS)

    Alenezi, Mohammad R.; Henley, Simon J.; Silva, S. R. P.

    2015-02-01

    Developing rationally controlled bottom-up device fabrication processes is essential for the achievement of high performance optimal devices. We report a controlled, seedless and site-selective hydrothermal technique to fabricate high-performance nanostructured ZnO UV-detectors directly on-chip. We demonstrate that by controlling the nanowire growth process, via tuning the experimental parameters such as the concentration of reactants and the growth time, and by introducing a refresh of the growth solution, the device structure efficiency can be enhanced to significantly improve its performance. The on-chip fabricated bridging nanosyringe ultraviolet detector demonstrates improved sensitivity (~105), nanowatts detectability, and ultrafast response-time (90 ms) and recovery-time (210 ms). The improvement in response-time and recovery-time is attributed to the unique nanowire-nanowire junction barrier dominated resistance and the direct contact between ZnO and Au electrodes. Furthermore, the enhanced sensitivity and nanowatts detectability of the bridging nanosyringe device are due to the reduction in dimensionality and ultrahigh surface-to-volume ratio. This work paves the way toward low cost, large scale, low temperature, seedless and site-selective fabrication of high performance ZnO nanowire sensors on flexible and transparent substrates.

  10. Fabrication of a 3-dimensional nanostructured binary colloidal crystal within a confined channel.

    PubMed

    Gorey, Brian; Smyth, Malcolm R; Morrin, Aoife; White, Blánaid

    2014-12-15

    The reproducible fabrication of nanostructured 3Dimensional (3D) binary colloidal crystal (bCC) in a defined geometric space through a simple one step process is detailed. This method allows for the potential fabrication of a bCC in a sealed μchip within a defined area or channel by capillary forces, unlike other bCC formation methods such as dip-drawing, where the substrate must be submerged in a suspension to form a bCC, or bCC monolayers, which are fabricated at the water air interface. Through simple variation in volume fraction ratio (VF(S/L)) of nano-(denoted small, S) and macro-sized (denoted large, L) polystyrene (PS) spheres and diameter size ratio (D(S/L)), the manipulation of bCC structures was also achieved. Variation of nano-sized PS sphere number within the interstitial voids formed between neighbouring macro-sized spheres enabled the reproducible fabrication of LS2 and LS6 structures, which contain 1 and 3 nano-spheres respectively in each interstitial void. It must be noted that while VF(S/L) allows for control of the final LSn structure, thickness of bCC formation in this manner is independent of VFS/L. PMID:25268825

  11. Prediction of Yarn Strength Utilization in Cotton Woven Fabrics using Artificial Neural Network

    NASA Astrophysics Data System (ADS)

    Mishra, Swapna

    2015-10-01

    The paper presents an endeavor to predict the percentage yarn strength utilization (% SU) in cotton woven fabrics using artificial neural network approach. Fabrics in plain, 2/2 twill, 3/1 twill and 4-end broken twill weaves having three pick densities and three weft counts in each weave have been considered. Different artificial neural network models, with different set of input parameters, have been explored. It has been found that % SU can be predicted fairly accurately by only five fabric parameters, namely the number of load bearing and transverse yarns per unit length, the yarn crimp % in the load bearing and transverse directions and the float length of the weave. Trend analysis of the artificial neural network model has also been carried out to see how the various parameters affect the % SU. The results indicate that while an increase in the number of load bearing or transverse yarns increases the % SU, an increase in the float length and the crimp % in the yarns have a detrimental effect.

  12. Design, fabrication, and characterization of metallic nanostructures for surface-enhanced Raman spectroscopy and plasmonic applications

    NASA Astrophysics Data System (ADS)

    Hao, Qingzhen

    Metal/dielectric nanostructures have the ability to sustain coherent electron oscillations known as surface plasmons. Due to their capability of localizing and guiding light in sub-wavelength metal nanostructures beyond diffraction limits, surface plasmon-based photonics, or “plasmonics” has opened new physical phenomena and lead to novel applications in metamaterials, optoelectronics, surface enhanced spectroscopy and biological sensing. This dissertation centers on design, fabrication, characterization of metallic nanostructures and their applications in surface-enhanced Raman spectroscopy (SERS) and actively tunable plasmonics. Metal-dielectric nanostructures are the building blocks for photonic metamaterials. One valuable design guideline for metamaterials is the Babinet’s principle, which governs the optical properties of complementary nanostructures. However, most complementary metamaterials are designed for the far infrared region or beyond, where the optical absorption of metal is small. We have developed a novel dual fabrication method, capable of simultaneously producing optically thin complementary structures. From experimental measurements and theoretical simulations, we showed that Babinet’s principle qualitatively holds in the visible region for the optically thin complements. The complementary structure is also a good platform to study subtle differences between nanoparticles and nanoholes in SERS (a surface sensitive technique, which can enhance the conventional Raman cross-section by 106˜108 fold, thus very useful for highly sensitive biochemical sensing). Through experimental measurement and theoretical analysis, we showed that the SERS enhancement spectrum (plot of SERS enhancement versus excitation wavelengths), dominated by local near-field, for nanoholes closely follows their far-field optical transmission spectrum. However, the enhancement spectrum for nanoparticles red-shifts significantly from their far-field optical extinction

  13. Fabrication and characterization of nanostructured Mg-doped CdS/AAO nanoporous membrane for sensing applications

    NASA Astrophysics Data System (ADS)

    Shaban, Mohamed; Mustafa, Mona; Hamdy, Hany

    2016-04-01

    In this study, Mg-doped CdS nanostructure was deposited onto anodic aluminum oxide (AAO) membrane substrate using sol-gel spin coating method. The AAO membrane was prepared by a two-step anodization process combined with pore widening process. The morphology, chemical composition, and structure of the spin- coated CdS nanostructure have been studied. The morphology of the fabricated AAO membrane and the deposited Mg-doped CdS nanostructure was investigated using scanning electron microscopy (SEM). The SEM of AAO illustrates a typical hexagonal and smooth nanoporous alumina membrane with interpore distance of ~ 100 nm, the pore diameter of ~ 60 nm. SEM of Mgdoped CdS shows porous nanostructured film of CdS nanoparticles. This film well adherents and covers the AAO substrate. The energy dispersive X-ray (EDX) pattern exhibits the signals of Al, O from AAO membrane and Mg, Cd, and S from the deposited CdS. This indicates the high purity of the fabricated membrane and the deposited Mg-doped CdS nanostructure. Using X-ray diffraction (XRD) pattern, Scherrer equation was used to calculate the average crystallite size. Additionally, the texture coefficients and density of dislocations were calculated. The fabricated CdS/AAO was applied to detect glucose of different concentrations. The proposed method has some advantages such as simple technology, low cost of processing, and high throughput. All of these factors facilitate the use of the prepared films in sensing applications.

  14. The concept and realization of nanostructure fabrication using free-standing metallic wires with rapid thermal annealing

    NASA Astrophysics Data System (ADS)

    Cui, AJuan; Hao, TingTing; Li, WuXia; Shen, TieHan; Liu, Zhe; Jiang, QianQing; Gu, ChangZhi

    2015-04-01

    Free-standing metallic nanostructures are considered to be highly relevant to many branches of science and technology with applications of three dimensional metallic nanostructures ranging from optical reflectors, actuators, and antenna, to free-standing electrodes, mechanical, optical, and electrical resonators and sensors. Strain-induced out-of-plane fabrication has emerged as an effective method which uses relaxation of strain-mismatched materials. In this work, we report a study of the thermal annealing-induced shape modification of free-standing nanostructures, which was achieved by introducing compositional or microstructural nonuniformity to the nanowires. In particular gradient, segmented and striped hetero-nanowires were grown by focused-ion-beam-induced chemical vapor deposition, followed by rapid thermal annealing in a N2 atmosphere. Various free-standing nanostructures were produced as a result of the crystalline/grain growth and stress relief.

  15. Direct fabrication of complex 3D hierarchical nanostructures by reactive ion etching of hollow sphere colloidal crystals.

    PubMed

    Zhong, Kuo; Li, Jiaqi; Van Cleuvenbergen, Stijn; Clays, Koen

    2016-09-21

    Direct reactive ion etching (RIE) of hollow SiO2 sphere colloidal crystals (HSCCs) is employed as a facile, low-cost method to fabricate complex three-dimensional (3D) hierarchical nanostructures. These multilayered structures are gradually transformed into nanostructures of increasing complexity by controlling the etching time, without complicated procedures (no mask needed). The resulting 3D topologies are unique, and cannot be obtained through traditional approaches. The formation mechanism of these structures is explained in detail by geometrical modeling during the different etching stages, through shadow effects of the higher layers. SEM images confirm the modeled morphological changes. The nanostructures obtained by our approach show very fine features as small as ∼30 nm. Our approach opens new avenues to directly obtain complex 3D nanostructures from colloidal crystals and can find applications in sensing, templating, and catalysis where fine tuning the specific surface might be critical. PMID:27545098

  16. Sub-5 nm nanostructures fabricated by atomic layer deposition using a carbon nanotube template.

    PubMed

    Woo, Ju Yeon; Han, Hyo; Kim, Ji Weon; Lee, Seung-Mo; Ha, Jeong Sook; Shim, Joon Hyung; Han, Chang-Soo

    2016-07-01

    The fabrication of nanostructures having diameters of sub-5 nm is very a important issue for bottom-up nanofabrication of nanoscale devices. In this work, we report a highly controllable method to create sub-5 nm nano-trenches and nanowires by combining area-selective atomic layer deposition (ALD) with single-walled carbon nanotubes (SWNTs) as templates. Alumina nano-trenches having a depth of 2.6 ∼ 3.0 nm and SiO2 nano-trenches having a depth of 1.9 ∼ 2.2 nm fully guided by the SWNTs have been formed on SiO2/Si substrate. Through infilling ZnO material by ALD in alumina nano-trenches, well-defined ZnO nanowires having a thickness of 3.1 ∼ 3.3 nm have been fabricated. In order to improve the electrical properties of ZnO nanowires, as-fabricated ZnO nanowires by ALD were annealed at 350 °C in air for 60 min. As a result, we successfully demonstrated that as-synthesized ZnO nanowire using a specific template can be made for various high-density resistive components in the nanoelectronics industry. PMID:27188268

  17. Sub-5 nm nanostructures fabricated by atomic layer deposition using a carbon nanotube template

    NASA Astrophysics Data System (ADS)

    Woo, Ju Yeon; Han, Hyo; Kim, Ji Weon; Lee, Seung-Mo; Ha, Jeong Sook; Shim, Joon Hyung; Han, Chang-Soo

    2016-07-01

    The fabrication of nanostructures having diameters of sub-5 nm is very a important issue for bottom-up nanofabrication of nanoscale devices. In this work, we report a highly controllable method to create sub-5 nm nano-trenches and nanowires by combining area-selective atomic layer deposition (ALD) with single-walled carbon nanotubes (SWNTs) as templates. Alumina nano-trenches having a depth of 2.6 ∼ 3.0 nm and SiO2 nano-trenches having a depth of 1.9 ∼ 2.2 nm fully guided by the SWNTs have been formed on SiO2/Si substrate. Through infilling ZnO material by ALD in alumina nano-trenches, well-defined ZnO nanowires having a thickness of 3.1 ∼ 3.3 nm have been fabricated. In order to improve the electrical properties of ZnO nanowires, as-fabricated ZnO nanowires by ALD were annealed at 350 °C in air for 60 min. As a result, we successfully demonstrated that as-synthesized ZnO nanowire using a specific template can be made for various high-density resistive components in the nanoelectronics industry.

  18. Fabrication and characterization of graphitic carbon nanostructures with controllable size, shape, and position.

    PubMed

    Du, Rongbing; Ssenyange, Solomon; Aktary, Mirwais; McDermott, Mark T

    2009-05-01

    The incorporation of carbon materials in micro- and nanoscale devices is being widely investigated due to the promise of enhanced functionality. Challenges in the positioning and addressability of carbon nanotubes provide the motivation for the development of new processes to produce nanoscale carbon materials. Here, the fabrication of conducting, nanometer-sized carbon structures using a combination of electron beam lithography (EBL) and carbonisation is reported. EBL is used to directly write predefined nanometer-sized patterns in a thin layer of negative resist in controllable locations. Careful heat treatment results in carbon nanostructures with the size, shape, and location originally defined by EBL. The pyrolysis process results in significant shrinkage of the structures in the vertical direction and minimal loss in the horizontal direction. Characterization of the carbonized material indicates a structure consisting of both amorphous and graphitized carbon with low levels of oxygen. The resistivity of the material is similar to other disordered carbon materials and the resistivity is maintained from the bulk to the nanoscale. This is demonstrated by fabricating a nanoscale structure with predictable resistance. The ability to fabricate these conductive structures with known dimensions and in predefined locations can be exploited for a number of applications. Their use as nanoband electrodes is also demonstrated. PMID:19235195

  19. Fabrication of large scale nanostructures based on a modified atomic force microscope nanomechanical machining system.

    PubMed

    Hu, Z J; Yan, Y D; Zhao, X S; Gao, D W; Wei, Y Y; Wang, J H

    2011-12-01

    The atomic force microscope (AFM) tip-based nanomechanical machining has been demonstrated to be a powerful tool for fabricating complex 2D∕3D nanostructures. But the machining scale is very small, which holds back this technique severely. How to enlarge the machining scale is always a major concern for the researches. In the present study, a modified AFM tip-based nanomechanical machining system is established through combination of a high precision X-Y stage with the moving range of 100 mm × 100 mm and a commercial AFM in order to enlarge the machining scale. It is found that the tracing property of the AFM system is feasible for large scale machining by controlling the constant normal load. Effects of the machining parameters including the machining direction and the tip geometry on the uniform machined depth with a large scale are evaluated. Consequently, a new tip trace and an increasing load scheme are presented to achieve a uniform machined depth. Finally, a polymer nanoline array with the dimensions of 1 mm × 0.7 mm, the line density of 1000 lines/mm and the average machined depth of 150 nm, and a 20 × 20 polymer square holes array with the scale of 380 μm × 380 μm and the average machined depth of 250 nm are machined successfully. The uniform of the machined depths for all the nanostructures is acceptable. Therefore, it is verified that the AFM tip-based nanomechanical machining method can be used to machine millimeter scale nanostructures. PMID:22225244

  20. Electroactive nanostructured polymer actuators fabricated using sulfonated styrenic pentablock copolymer/montmorillonite/ionic liquid nanocomposite membranes

    NASA Astrophysics Data System (ADS)

    Lee, Jang-Woo; Hong, Soon Man; Koo, Chong Min

    2014-08-01

    High-bendable, air-operable ionic polymer-metal composite (IPMC) actuators composed of electroactive nanostructured middle-block sulfonated styrenic pentablock copolymer (SSPB)/sulfonated montmorillonite (s-MMT) nanocomposite electrolyte membranes with bulky imidazolium ionic liquids (ILs) incorporated were fabricated and their bending actuation performances were evaluated. The SSPB-based IPMC actuators showed larger air-operable bending displacements, higher displacement rates, and higher energy efficiency of actuations without conventional IPMC bottlenecks, including back relaxation and actuation instability during actuation in air, than the Nafion counterpart. Incorporation of s-MMT into the SSPB matrix further enhanced the actuation performance of the IPMC actuators in terms of displacement, displacement rate, and energy efficiency. The remarkably high performance of the SSPB/s-MMT/IL IPMCs was considered to be due to the microphase-separated large ionic domains of the SSPB (the average diameter of the ionic domain: ca. 20 nm) and the role of s-MMT as an ionic bridge between the ionic domains, and the ion pumping effect of the bulky imidazolium cations of the ILs as well. The microphase-separated nanostructure of the composite membranes caused a high dimensional stability upon swelling in the presence of ILs, which effectively preserved the original electrode resistance against swelling, leading to a high actuation performance of IPMC.

  1. A new approach to the fabrication of ``smart`` near-surface nanostructure composites

    SciTech Connect

    Gea, L.; Honda, S.; Boatner, L.A.; Haynes, T.E.; Sales, B.C.; Modine, F.A.; Meldrum, A.; Budai, J.D.; Beckers, L.

    1998-01-01

    A new method for the formation of smart near-surface nanoscale composites has been developed. In this approach, small precipitates of active phases are embedded in the near-surface region of the material that is to be modified by a combination of ion implantation and thermal processing. The dispersion, concentration, and microstructure of the nanocrystals formed in the substrate material can be tailored through a careful choice of processing parameters - making this approach well suited to high value added, high technology applications. The applicability of this approach to forming smart surfaces on otherwise inactive materials was established in the case of VO{sup 2} precipitates which were embedded in Al{sub 2}O{sub 3} single crystals to create a medium suitable for optical applications--including optical data storage. Most recently, this concept has been extended to the fabrication of magnetic field sensitive nanostructured surfaces by forming magnetostrictive precipitates of materials such as Ni or RFe{sub 2} (with R = Tm, Tb, Sm) that are embedded in various single crystal oxide hosts. These nanostructured, active surface composites have been characterized using XRD, RBS, TEM, and magneto-optical techniques.

  2. An Antireflective Nanostructure Array Fabricated by Nanosilver Colloidal Lithography on a Silicon Substrate

    PubMed Central

    2010-01-01

    An alternative method is presented for fabricating an antireflective nanostructure array using nanosilver colloidal lithography. Spin coating was used to produce the multilayered silver nanoparticles, which grew by self-assembly and were transformed into randomly distributed nanosilver islands through the thermodynamic action of dewetting and Oswald ripening. The average size and coverage rate of the islands increased with concentration in the range of 50–90 nm and 40–65%, respectively. The nanosilver islands were critically affected by concentration and spin speed. The effects of these two parameters were investigated, after etching and wet removal of nanosilver residues. The reflection nearly disappeared in the ultraviolet wavelength range and was 17% of the reflection of a bare silicon wafer in the visible range. PMID:21076677

  3. Fabrication of nano-structured hemispheres and pillars using laterally migrating polymer templates.

    PubMed

    Nam, Hye Jin; Yi, Gi-Ra; Jeong, Seong-Hun; Boo, Jin-Hyo; Jung, Duk-Young

    2009-10-01

    We report herein a reliable method of fabricating 2D periodic gold nanopillars with well-defined anisotropic shapes by the combinational actions of colloidal crystals and gold evaporation. The deposition of gold on a polymer template produced dual functional Janus-like nanopillars up to 633 nm in height as well as hemispherical shells with 120 nm. The thermal-induced active migration of the nanopillars from the pristine position in the lateral direction occurred at the colloidal defects while some cavity space was formed inside the gold pillars. The nano-structured gold pillars exhibited a strong surface plasmon resonance at 598 nm, as compared to that of the solid gold nanospheres at 520 nm, and a noticeable red shift to 640 nm was induced by the removal of the polymer template. PMID:19908488

  4. Fabrication of silica nanostructures with a microwave assisted direct patterning process

    NASA Astrophysics Data System (ADS)

    Shin, Ju-Hyeon; Go, Bit-Na; Choi, Je-Hong; Kim, Jin-Seoung; Jung, Gun-Young; Kim, Heetae; Lee, Heon

    2014-06-01

    Silica nanostructures were fabricated on glass substrate using a microwave assisted direct patterning (MADP) process, which is a variety of soft lithography. During the MADP process using polydimethylsiloxane (PDMS), mold and microwave heating are performed simultaneously. Blanket thin film and micro- to nano-sized structures, including moth-eye patterns of SiO2, which consisted of coalesced silica nanoparticles, were formed on glass substrates from SiO2 nano-particle dispersed solutions with varied microwave heating time. Optical properties and surface morphologies of micro-sized hemisphere, nano-sized pillar, moth-eye and 50 nm sized line/space silica patterns were measured using UV-vis and a scanning electron microscope. X-ray diffraction analysis of SiO2 thin films with and without microwave heating was also carried out.

  5. The facile fabrication of tunable plasmonic gold nanostructure arrays using microwave plasma

    NASA Astrophysics Data System (ADS)

    Hsu, Chuen-Yuan; Huang, Jing-Wen; Gwo, Shangjr; Lin, Kuan-Jiuh

    2010-01-01

    Fabrication of isolated noble metal nanoparticles embedded in transparent substrates is the fasting growing demand for innovative plasmonic technologies. Here we report a simple and effective methodology for the preparation of highly stable plasmonic nanoparticles embedded in a glass surface. Size-controllable (10-70 nm) Au nanoparticles were rapidly prepared when subjected to the home-microwave plasma. Accordingly, the optical extinction maximum of the localized surface plasmon resonance (LSPR) can be systematically tuned in the range 532-586 nm. We find that the plasmonic structures are exceedingly stable toward immersion in ethanol solvents and pass successfully the adhesive tape test, which makes our system highly promising for efficient transmission-LSPR nanosensors. Besides, the attractive features of substrate-bound plasmonic nanostructures include its low cost, versatility, robustness, reusability and a promising ability to make a multi-arrayed LSPR biochip.

  6. Mechanism behind the surface evolution and microstructure changes of laser fabricated nanostructured carbon composite

    NASA Astrophysics Data System (ADS)

    Foong, Y. M.; Koh, A. T. T.; Ng, H. Y.; Chua, D. H. C.

    2011-09-01

    Many studies have shown that amorphous carbon films with reduced internal stress, improved adhesion strength, and diversified material properties are obtainable through doping process, but the presence of dopants was reported to promote surface evolution and alter the microstructures of carbon matrix. By combining analyses from experimental results and theoretical estimations, this work examines the mechanism behind the surface evolution and microstructural changes in laser fabricated nanostructured copper-carbon composite. We showed that the presence of metal ions during laser deposition increased the heat dissipation on carbon matrix, which enhanced the formation of nanoislands but graphitized the carbon matrix. In addition, theoretical estimations and XPS hinted that the presence of energetic species may force the carbon ions to react with the substrate interface and form silicon carbide bonds, which contributed to the improved adhesion strength observed in copper doped carbon films, along with a reduction in internal stress owing to the presence of nanoclusters.

  7. Fabrication of silica nanostructures with a microwave assisted direct patterning process.

    PubMed

    Shin, Ju-Hyeon; Go, Bit-Na; Choi, Je-Hong; Kim, Jin-Seoung; Jung, Gun-Young; Kim, Heetae; Lee, Heon

    2014-06-01

    Silica nanostructures were fabricated on glass substrate using a microwave assisted direct patterning (MADP) process, which is a variety of soft lithography. During the MADP process using polydimethylsiloxane (PDMS), mold and microwave heating are performed simultaneously. Blanket thin film and micro- to nano-sized structures, including moth-eye patterns of SiO2, which consisted of coalesced silica nanoparticles, were formed on glass substrates from SiO2 nano-particle dispersed solutions with varied microwave heating time. Optical properties and surface morphologies of micro-sized hemisphere, nano-sized pillar, moth-eye and 50 nm sized line/space silica patterns were measured using UV-vis and a scanning electron microscope. X-ray diffraction analysis of SiO2 thin films with and without microwave heating was also carried out. PMID:24833169

  8. Au(I)-thiolate nanostructures fabricated by chemical exfoliation and their transformation to gold nanoparticle assemblies.

    PubMed

    Nie, Hui; Li, Minjie; Hao, Yajiao; Wang, Xudong; Gao, Sheng; Yang, Bingjie; Gu, Mengdi; Sun, Linlin; Zhang, Sean Xiao-An

    2014-11-15

    Chemical exfoliation method was applied to transform bulky assemblies of Au(I)-3-mercaptopropionate (MPA) coordination polymer (CP) to nanosheets and nanostrings using sodium citrate as an exfoliator. The exfoliation process and the structural characteristics of the Au(I)-MPA nanosheets and nanostrings were fully investigated by transmission electron microscopy, atomic force microscopy, UV-vis absorption spectroscopy, X-ray photoelectron spectroscopy and so on. As the structural rigidity and stability of the obtained Au(I)-MPA nanosheets, they are ideal precursors for fabrication of water soluble gold nanoparticle assemblies through progressive pyrolysis. This work provides a significant strategy toward the morphology regulation of CP nanostructures and will inspire further development of this research area. PMID:25170603

  9. Extremely superhydrophobic surfaces with micro- and nanostructures fabricated by copper catalytic etching.

    PubMed

    Lee, Jung-Pil; Choi, Sinho; Park, Soojin

    2011-01-18

    We demonstrate a simple method for the fabrication of rough silicon surfaces with micro- and nanostructures, which exhibited superhydrophobic behaviors. Hierarchically rough silicon surfaces were prepared by copper (Cu)-assisted chemical etching process where Cu nanoparticles having particle size of 10-30 nm were deposited on silicon surface, depending on the period of time of electroless Cu plating. Surface roughness was controlled by both the size of Cu nanoparticles and etching conditions. As-synthesized rough silicon surfaces showed water contact angles ranging from 93° to 149°. Moreover, the hierarchically rough silicon surfaces were chemically modified by spin-coating of a thin layer of Teflon precursor with low surface energy. And thus it exhibited nonsticky and enhanced hydrophobic properties with extremely high contact angle of nearly 180°. PMID:21162520

  10. Three-dimensional fabrication of metallic nanostructures over large areas by two-photon polymerization.

    PubMed

    Formanek, Florian; Takeyasu, Nobuyuki; Tanaka, Takuo; Chiyoda, Kenta; Ishikawa, Atsushi; Kawata, Satoshi

    2006-01-23

    An experimental protocol for the realization of three-dimensional periodic metallic micro/nanostructures over large areas is presented. Simultaneous fabrication of hundreds of three-dimensional complex polymer structures is achieved using a two-photon photopolymerization (TPP) technique combined with a microlens array. Metallization of the structures is performed through the deposition of thin and highly conductive films by electroless plating. A chemical modification of the photopolymerizable resin and the production of a hydrophobic coating on the glass surface supporting the structures are realized. This process prevents metal deposition on the substrate and restricts adhesion on polymer. Our technique can produce periodic and/or isolated metallic structures with arbitrary shape, created by more than 700 individual objects written in parallel. PMID:19503400

  11. Impact of parameter variation in fabrication of nanostructure by atomic force microscopy nanolithography.

    PubMed

    Dehzangi, Arash; Larki, Farhad; Hutagalung, Sabar D; Goodarz Naseri, Mahmood; Majlis, Burhanuddin Y; Navasery, Manizheh; Hamid, Norihan Abdul; Noor, Mimiwaty Mohd

    2013-01-01

    In this letter, we investigate the fabrication of Silicon nanostructure patterned on lightly doped (10(15) cm(-3)) p-type silicon-on-insulator by atomic force microscope nanolithography technique. The local anodic oxidation followed by two wet etching steps, potassium hydroxide etching for silicon removal and hydrofluoric etching for oxide removal, are implemented to reach the structures. The impact of contributing parameters in oxidation such as tip materials, applying voltage on the tip, relative humidity and exposure time are studied. The effect of the etchant concentration (10% to 30% wt) of potassium hydroxide and its mixture with isopropyl alcohol (10%vol. IPA ) at different temperatures on silicon surface are expressed. For different KOH concentrations, the effect of etching with the IPA admixture and the effect of the immersing time in the etching process on the structure are investigated. The etching processes are accurately optimized by 30%wt. KOH +10%vol. IPA in appropriate time, temperature, and humidity. PMID:23776479

  12. Facile fabrication of cobalt oxalate nanostructures with superior specific capacitance and super-long cycling stability

    NASA Astrophysics Data System (ADS)

    Cheng, Guanhua; Si, Conghui; Zhang, Jie; Wang, Ying; Yang, Wanfeng; Dong, Chaoqun; Zhang, Zhonghua

    2016-04-01

    Transition metal oxalate materials have shown huge competitive advantages for applications in supercapacitors. Herein, nanostructured cobalt oxalate supported on cobalt foils has been facilely fabricated by anodization, and could directly serve as additive/binder-free electrodes for supercapacitors. The as-prepared cobalt oxalate electrodes present superior specific capacitance of 1269 F g-1 at the current density of 6 A g-1 in the galvanostatic charge/discharge test. Moreover, the retained capacitance is as high as 87.2% as the current density increases from 6 A g-1 to 30 A g-1. More importantly, the specific capacitance of cobalt oxalate retains 91.9% even after super-long cycling of 100,000 cycles. In addition, an asymmetric supercapacitor assembled with cobalt oxalate (positive electrode) and activated carbon (negative electrode) demonstrates excellent capacitive performance with high energy density and power density.

  13. Fabrication and characterization of ultrathin dextran layers: Time dependent nanostructure in aqueous environments revealed by OWLS.

    PubMed

    Saftics, Andras; Kurunczi, Sándor; Szekrényes, Zsolt; Kamarás, Katalin; Khánh, Nguyen Quoc; Sulyok, Attila; Bősze, Szilvia; Horvath, Robert

    2016-10-01

    Surface coatings of the polysaccharide dextran and its derivatives are key ingredients especially in label-free biosensors for the suppression of non-specific binding and for receptor immobilization. Nevertheless, the nanostructure of these ultrathin coatings and its tailoring by the variation of the preparation conditions have not been profoundly characterized and understood. In this work carboxymethylated dextran (CMD) was prepared and used for fabricating ultrathin surface coatings. A grafting method based on covalent coupling to aminosilane- and epoxysilane-functionalized surfaces was applied to obtain thin CMD layers. The carboxyl moiety of the CMD was coupled to the aminated surface by EDC-NHS reagents, while CMD coupling through epoxysilane molecules was performed without any additional reagents. The surface analysis following the grafting procedures consisted of X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared spectroscopy (ATR-IR), spectroscopic ellipsometry, atomic force microscopy (AFM) and optical waveguide lightmode spectroscopy (OWLS). The XPS and AFM measurements showed that the grafting resulted in a very thin dextran layer of a few nanometers. The OWLS method allowed devising the structure of the interfacial dextran layers by the evaluation of the optogeometrical parameters. The alteration in the nanostructure of the CMD layer with the chemical composition of the silane coverage and the pH of the grafting solution was revealed by in situ OWLS, specifically, lain down chains were found to be prevalent on the surface under neutral and basic conditions on epoxysilylated surfaces. The developed methodologies allowed to design and fabricate nanometer scale CMD layers with well-controlled surface structure, which are very difficult to characterize in aqueous environments using present instrumentations and highly hydrated surface layers. PMID:27455406

  14. Nanostructured grating patterns over a large area fabricated by optically directed assembly

    NASA Astrophysics Data System (ADS)

    Huang, Xiaoping; Chen, Kai; Qi, Mingxi; Li, Yu; Hou, Yumeng; Wang, Ying; Zhao, Qing; Luo, Xiangang; Xu, Qingyu

    2016-07-01

    Optical trapping and manipulation of nanoparticles (NPs) have been widely used in nanotechnology and biology. Here, we demonstrate an optically directed assembly (ODA) route for bottom-up fabrication of stable nanostructured grating patterns in solution using laser standing evanescent wave (LSEW) fields. The control mechanism is the intriguing cooperative action of the periodically line-centered attractive optical gradient force and the near field dipolar coupling force induced by LSEW, which leads to assembly of the colloidal silver NPs into robust grating patterns within minutes. The anisotropic polarization nature of the grating patterns was studied further by examining the morphology correlation of the surface-enhanced Raman scattering (SERS)-based signal amplification. We show the LSEW ODA method can optimize and stabilize the strongest dipolar coupling style among the NPs during pattern assembly. These results advance the further understanding of ODA of colloid NPs and might have many potential applications in SERS, catalysis, nanophotonics and nano-fabrication.Optical trapping and manipulation of nanoparticles (NPs) have been widely used in nanotechnology and biology. Here, we demonstrate an optically directed assembly (ODA) route for bottom-up fabrication of stable nanostructured grating patterns in solution using laser standing evanescent wave (LSEW) fields. The control mechanism is the intriguing cooperative action of the periodically line-centered attractive optical gradient force and the near field dipolar coupling force induced by LSEW, which leads to assembly of the colloidal silver NPs into robust grating patterns within minutes. The anisotropic polarization nature of the grating patterns was studied further by examining the morphology correlation of the surface-enhanced Raman scattering (SERS)-based signal amplification. We show the LSEW ODA method can optimize and stabilize the strongest dipolar coupling style among the NPs during pattern assembly

  15. Fabrication of porous hydroxyapatite scaffolds as artificial bone preform and its biocompatibility evaluation.

    PubMed

    Jang, Dong-Woo; Franco, Rose Ann; Sarkar, Swapan Kumar; Lee, Byong-Taek

    2014-01-01

    In this study, a novel porous hydroxyapatite scaffold was designed and fabricated to imitate natural bone through a multipass extrusion process. The conceptual design manifested unidirectional microchannels at the exterior part of the scaffold to facilitate rapid biomineralization and a central canal that houses the bone marrow. External and internal fissures were minimized during microwave sintering at 1,100 °C. No deformation was noted, and a mechanically stable scaffold was fabricated. Detailed microstructure of the fabricated artificial bone was examined by scanning electron microscope and X-ray diffractometer, and material properties like compressive strength were evaluated. The initial biocompatibility was examined by the cell proliferation of MG-63 osteoblast-like cells using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Preliminary in vivo investigation in a rabbit model after 4 weeks and 8 weeks of implantation showed full osteointegration of the scaffold with the native tissue, and formation of bone tissue within the pore network, as examined by microcomputed tomography analyses and histological staining. Osteon-like bone microarchitecture was observed along the unidirectional channel with microblood vessels. These confirm a biomimetic regeneration model in the implanted bone scaffold, which can be used as an artificial alternative for damaged bone. PMID:24399056

  16. Molecular separations using nanostructured porous thin films fabricated by glancing angle deposition

    NASA Astrophysics Data System (ADS)

    Bezuidenhout, Louis Wentzel

    Biomolecular separation techniques are an enabling technology that indirectly in.uence many aspects of our lives. Advances have led to faster analyses, reduced costs, higher specificity, and new analytical techniques, impacting areas such as health care, environmental monitoring, polymer sciences, agriculture, and nutrition. Further development of separations technology is anticipated to follow the path of computing technology such that miniaturization through the development of microfluidics technology, lab-on-a-chip systems, and other integrative, multi-component systems will further extend our analysis capabilities. Creation of new and improvement of existing separation technologies is an integral part of the pathway to miniaturized systems. the work of this thesis investigates molecular separations using porous nanostructured films fabricated by the thin film process glancing angle deposition (GLAD). Structural architecture, pore size and shape, and film density can be finely controlled to produce high-surface area thin films with engineered morphology. The characteristic size scales and structural control of GLAD films are well-suited to biomolecules and separation techniques, motivating investigation into the utility and performance of GLAD films for biomolecular separations. This project consisted of three phases. First, chromatographic separation of dye molecules on silica GLAD films was demonstrated by thin layer chromatography Direct control of film nanostructure altered the separation characteristics; most strikingly, anisotropic structures provided two-dimensional analyte migration. Second, nanostructures made with GLAD were integrated in PDMS microfluidic channels using a sacrificial etching process; DNA molecules (10/48 kbp and 6/10/20 kbp mixtures) were electrophoretically separated on a microfluidic chip using a porous bed of SiO2 vertical posts. Third, mass spectrometry of proteins and drugs in the mass range of 100-1300 m/z was performed using

  17. Influence of the scanning conditions on the characteristics of the nanostructures fabricated by laser ablation in liquid

    NASA Astrophysics Data System (ADS)

    Nikolov, A. S.; Nikov, R. G.; Nedyalkov, N. N.; Koutzarova, T. I.; Alexandrov, M. T.; Karashanova, D. B.; Ristoscu, C.; Mihailescu, I. N.

    2015-01-01

    Pulsed laser ablation was used to create Ag nanostructures - nanoparticles and nanowires. Two different type of target motion were used - rotation and computer controlled by using an XY stage. The impact was investigated of the trajectory of the laser beam on the target surface on the characteristics of the ablation process itself and the nanostructures obtained. Two circular trajectories of different diameters generated at the target rotation were utilized. The fundamental (λ = 1064 nm) and the third harmonic (λTHG = 355 nm) wavelengths of a Nd-YAG laser system were used for the fabrication procedure. They were selected in order to study the influence of the two processes accompanying the ablation procedure, namely, scattering and absorption of the incident light by the nanostructures already created (the so-called self-absorption). The two possible nanostructures - nanoparticles and nanowires, were obtained by an appropriate choice of the laser fluence for each of the wavelengths selected. The optical extinction spectra of the fabricated colloids allowed an indirect assessment of the shape and size-distribution of the nanostructures obtained, whose size and morphology were visualized by transmission electron microscopy (TEM). It was established that the most appropriate processing conditions in terms of the efficiency of the ablation and reproducibility of the sample characteristics were achieved using a computer controlled XY stage.

  18. The fabrication of diversiform nanostructure forests based on residue nanomasks synthesized by oxygen plasma removal of photoresist

    NASA Astrophysics Data System (ADS)

    Mao, Haiyang; Wu, Di; Wu, Wengang; Xu, Jun; Hao, Yilong

    2009-11-01

    A simple lithography-free approach for fabricating diversiform nanostructure forests is presented. The key technique of the approach is that randomly distributed nanoscale residues can be synthesized on substrates simply by removing photoresist with oxygen plasma bombardment. These nanoresidues can function as masks in the subsequent etching process for nanopillars. By further spacer and then deep etching processes, a variety of forests composed of regular, tulip-like or hollow-head nanopillars as well as nanoneedles are successfully achieved in different etching conditions. The pillars have diameters of 30-200 nm and heights of 400 nm-3 µm. The needles reach several microns in height, with their tips less than 10 nm in diameter. Moreover, microstructures containing these nanostructure forests, such as surface microchannels, have also been fabricated. This approach is compatible with conventional micro/nano-electromechanical system (MEMS/NEMS) fabrication.

  19. Three-dimensional hydrogen silsesquioxane nanostructure fabrication by reversal room-temperature nanoimprint using poly(dimethylsiloxane) mold

    NASA Astrophysics Data System (ADS)

    Sugano, Norihiro; Okada, Makoto; Haruyama, Yuichi; Matsui, Shinji

    2015-06-01

    Room temperature (RT) nanoimprinting is an attractive technique for nanofabrication, because it is not required a thermal cycle or UV irradiation process. Previously, it has reported that RT-nanoimprinting enables the fabrication of nanostructures using hydrogen silsesquioxane (HSQ) as a resin. HSQ has the HSiO3/2 structure and transforms to SiOx, such as glass, upon annealing. We developed, for the first time, reversal nanoimprint using RT nanoimprint to fabricate a three-dimensional (3D) HSQ structure and succeeded in fabricating a 3D HSQ nanostructure with two cross-stacked layers. Furthermore, it was confirmed that the 3D HSQ structure has a sufficient interface adhesion between the upper and lower layers by a durability test using ultrasonic vibration and also that it was not deformed after an annealing treatment at 1000 °C.

  20. Bio-inspired artificial iridophores based on capillary origami: Fabrication and device characterization

    NASA Astrophysics Data System (ADS)

    Manakasettharn, Supone; Ashley Taylor, J.; Krupenkin, Tom N.

    2011-10-01

    Cephalopods have evolved complex optical mechanisms of dynamic skin color control based on mechanical actuation of micro-scale optical structures such as iridophores and chromatophores. In this work, we describe the design, fabrication, and characterization of bio-inspired artificial iridophores, which resemble microflowers with flexible reflective petals, based on capillary origami microstructures. Two methods of petal actuation have been demonstrated—one based on the electrowetting process and the other by volume change of the liquid droplet. These results were in good agreement with a model derived to characterize the actuation dynamics.

  1. Nanoscale topographical replication of graphene architecture by manufactured DNA nanostructures

    NASA Astrophysics Data System (ADS)

    Moon, Youngkwon; Shin, Jihoon; Seo, Soonbeom; Park, Sung Ha; Ahn, Joung Real

    2015-03-01

    Despite many studies on how geometry can be used to control the electronic properties of graphene, certain limitations to fabrication of designed graphene nanostructures exist. Here, we demonstrate controlled topographical replication of graphene by artificial deoxyribonucleic acid (DNA) nanostructures. Owing to the high degree of geometrical freedom of DNA nanostructures, we controlled the nanoscale topography of graphene. The topography of graphene replicated from DNA nanostructures showed enhanced thermal stability and revealed an interesting negative temperature coefficient of sheet resistivity when underlying DNA nanostructures were denatured at high temperatures.

  2. Fabrication of Acrylonitrile-Butadiene-Styrene Nanostructures with Anodic Alumina Oxide Templates, Characterization and Biofilm Development Test for Staphylococcus epidermidis

    PubMed Central

    Desrousseaux, Camille; Cueff, Régis; Aumeran, Claire; Garrait, Ghislain; Mailhot-Jensen, Bénédicte; Traoré, Ousmane; Sautou, Valérie

    2015-01-01

    Medical devices can be contaminated by microbial biofilm which causes nosocomial infections. One of the strategies for the prevention of such microbial adhesion is to modify the biomaterials by creating micro or nanofeatures on their surface. This study aimed (1) to nanostructure acrylonitrile-butadiene-styrene (ABS), a polymer composing connectors in perfusion devices, using Anodic Alumina Oxide templates, and to control the reproducibility of this process; (2) to characterize the physico-chemical properties of the nanostructured surfaces such as wettability using captive-bubble contact angle measurement technique; (3) to test the impact of nanostructures on Staphylococcus epidermidis biofilm development. Fabrication of Anodic Alumina Oxide molds was realized by double anodization in oxalic acid. This process was reproducible. The obtained molds present hexagonally arranged 50 nm diameter pores, with a 100 nm interpore distance and a length of 100 nm. Acrylonitrile-butadiene-styrene nanostructures were successfully prepared using a polymer solution and two melt wetting methods. For all methods, the nanopicots were obtained but inside each sample their length was different. One method was selected essentially for industrial purposes and for better reproducibility results. The flat ABS surface presents a slightly hydrophilic character, which remains roughly unchanged after nanostructuration, the increasing apparent wettability observed in that case being explained by roughness effects. Also, the nanostructuration of the polymer surface does not induce any significant effect on Staphylococcus epidermidis adhesion. PMID:26284922

  3. Corn-like indium tin oxide nanostructures: fabrication, characterization and formation mechanism

    NASA Astrophysics Data System (ADS)

    Wu, Xu; Wang, Yihua; Yang, Bin

    2015-11-01

    Electrospinning is a simple but efficient procedure enabling the parallel fabrication of a multitude of inorganic fibers. But the precise control of the fiber's morphology, which seriously affects the electrical, optical and other important properties of such electrospun materials, is still less developed. The creation of nanoscale indium tin oxide fibers with corn-like geometry (corn-like ITO NFs) by our group has provided a good example to show how to modify the morphologies and properties of nanofibers by means of tailoring the fiber's compositions. Here we show that in the fabrication of corn-like ITO NFs, the usage of different solvents N, N-dimethylformamide (DMF) and deionized water, as well as the calcination temperature, can also lead to dramatic morphology changes, from ribbon-like to cylindrical and then to corn-like. The resultant nanoribbons and nanoscale corn-like fibers exhibit different photoluminescence properties. We find that the morphology of the as-spun fibers is closely related to the vapor pressure of the solvent we used, and the generation of ITO crystals sensitively depends on the calcination temperature, which both are critical for the morphology and properties of the final products. Thus, we demonstrate that the formation of this unprecedented nanostructure is determined by the combined effect of the precursor chemical composition, solvent and calcination temperature.

  4. Optical properties of silver/gold nanostructures fabricated by shadowing growth and their sensing applications

    NASA Astrophysics Data System (ADS)

    Fu, Junxue; Zhao, Yiping

    2010-08-01

    Various Ag and Au nanostructured films such as Ag nanoparticle (NP) films, Au NP films, and Au NP/TiO2/Au NP sandwich structures are fabricated by oblique angle deposition (OAD) and glancing angle deposition (GLAD) methods. Their optical absorbance properties and localized surface plasmon resonance (LSPR) have been studied systematically for samples prepared at different deposition conditions. Under the same deposition conditions, the Ag or Au NP substrates produced by GLAD method are more uniform and reproducible. The LSPR wavelength of Ag or Au NP substrates can be easily tuned by changing the film thickness, the deposition angle, and the coating of dielectric layer. The ability of the nanoparticle films as a chemical and biological biosensor has been explored by sensing the biomolecule NeutrAvidin and the bacterium Salmonella. Those NP films are very sensitive to chemical detection but are insensitive for bacteria detection. Based on Mie theory and effective medium theory, this is due to the small contact area between the nanoparticle and the bacteria, and the short range interaction of the local electric field. Our results demonstrate that shadowing based growth is a very versatile fabrication technique to produce reproducible and finetuned LSPR substrates.

  5. 3D ordered nanostructures fabricated by nanosphere lithography using an organometallic etch mask

    NASA Astrophysics Data System (ADS)

    Ling, Xing Yi; Acikgoz, Canet; Phang, In Yee; Hempenius, Mark A.; Reinhoudt, David N.; Vancso, G. Julius; Huskens, Jurriaan

    2010-08-01

    A new approach for fabricating porous structures on silicon substrates and on polymer surfaces, using colloidal particle arrays with a polymer mask of a highly etch-resistant organometallic polymer, is demonstrated. Monolayers of silica particles, with diameters of 60 nm, 150 nm, 300 nm, or 500 nm, were deposited either on a silicon substrate or on a surface coated with polyethersulfone (PES), and the voids of the arrays were filled with poly(ferrocenylmethylphenylsilane) (PFMPS). Argon ion sputtering removed the excess PFMPS on the particles which enabled removal of the particles with HF. Further pattern transfer steps with reactive ion etching for different time intervals provided structures in silicon or in a PES layer. Free-standing PES membranes exhibiting regular arrays of circular holes with high porosity were fabricated by using cellulose acetate as a sacrificial layer. The pores obtained on silicon substrates after etching were used as molds for nanoimprint lithography (NIL). A combination of the techniques of nanosphere lithography (NSL) and NIL has resulted in 3D nanostructures with a hemispherical shape (inherited from the nanoparticles) which was obtained both in silicon and in PMMA.

  6. Laser interference lithography for large area patterning and the fabrication of functional nanostructures

    NASA Astrophysics Data System (ADS)

    Wathuthanthri, Ishan

    nano-features onto different types of substrates using both additive and subtractive processes, resulting in the fabrication of functionalized nanostructures over a large substrate area. Finally, nanostructures are designed and fabricated to use the moth eye effect resulting in highly anti-reflective surfaces. These surfaces are then applied in SERS sensing as well as a mechanical anti-reflective layer for lithography process providing a highly robust mechanical anti-reflective layer with a much higher performance compared to traditional thin film anti-reflective coatings.

  7. Modeling, Fabrication and Characterization of Scalable Electroless Gold Plated Nanostructures for Enhanced Surface Plasmon Resonance

    NASA Astrophysics Data System (ADS)

    Jang, Gyoung Gug

    The scientific and industrial demand for controllable thin gold (Au) film and Au nanostructures is increasing in many fields including opto-electronics, photovoltaics, MEMS devices, diagnostics, bio-molecular sensors, spectro-/microscopic surfaces and probes. In this study, a novel continuous flow electroless (CF-EL) Au plating method is developed to fabricate uniform Au thin films in ambient condition. The enhanced local mass transfer rate and continuous deposition resulting from CF-EL plating improved physical uniformity of deposited Au films and thermally transformed nanoparticles (NPs). Au films and NPs exhibited improved optical photoluminescence (PL) and surface plasmon resonance (SPR), respectively, relative to batch immersion EL (BI-EL) plating. Suggested mass transfer models of Au mole deposition are consistent with optical feature of CF-EL and BI-EL films. The prototype CF-EL plating system is upgraded an automated scalable CF-EL plating system with real-time transmission UV-vis (T-UV) spectroscopy which provides the advantage of CF-EL plating, such as more uniform surface morphology, and overcomes the disadvantages of conventional EL plating, such as no continuous process and low deposition rate, using continuous process and controllable deposition rate. Throughout this work, dynamic morphological and chemical transitions during redox-driven self-assembly of Ag and Au film on silica surfaces under kinetic and equilibrium conditions are distinguished by correlating real-time T-UV spectroscopy with X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) measurements. The characterization suggests that four previously unrecognized time-dependent physicochemical regimes occur during consecutive EL deposition of silver (Ag) and Au onto tin-sensitized silica surfaces: self-limiting Ag activation; transitory Ag NP formation; transitional Au-Ag alloy formation during galvanic replacement of Ag by Au; and uniform morphology formation under

  8. CMOS-Compatible Top-Down Fabrication of Periodic SiO2 Nanostructures using a Single Mask.

    PubMed

    Meng, Lingkuan; Gao, Jianfeng; He, Xiaobin; Li, Junjie; Wei, Yayi; Yan, Jiang

    2015-12-01

    We propose a CMOS-compatible top-down fabrication technique of highly-ordered and periodic SiO2 nanostructures using a single amorphous silicon (α-Si) mask layer. The α-Si mask pattern is precisely transferred into the underlying SiO2 substrate material with a high fidelity by a novel top-down fabrication. It is the first time for α-Si film used as an etch mask to fabricate SiO2 nanostructures including nanoline, nanotrench, and nanohole arrays. It is observed that the α-Si mask can significantly reduce the pattern edge roughness and achieve highly uniform and smooth sidewalls. This behavior may be attributed to the presence of high concentration of dangling bonds in α-Si mask surface. By controlling the process condition, it is possible to achieve a desired vertical etched profile with a controlled size. Our results demonstrate that SiO2 pattern as small as sub-20 nm may be achievable. The obtained SiO2 pattern can be further used as a nanotemplate to produce periodic or more complex silicon nanostructures. Moreover, this novel top-down approach is a potentially universal method that is fully compatible with the currently existing Si-based CMOS technologies. It offers a greater flexibility for the fabrication of various nanoscale devices in a simple and efficient way. PMID:26306538

  9. The Enhanced Light Absorptance and Device Application of Nanostructured Black Silicon Fabricated by Metal-assisted Chemical Etching.

    PubMed

    Zhong, Hao; Guo, Anran; Guo, Guohui; Li, Wei; Jiang, Yadong

    2016-12-01

    We use metal-assisted chemical etching (MCE) method to fabricate nanostructured black silicon on the surface of C-Si. The Si-PIN photoelectronic detector based on this type of black silicon shows excellent device performance with a responsivity of 0.57 A/W at 1060 nm. Silicon nanocone arrays can be created using MCE treatment. These modified surfaces show higher light absorptance in the near-infrared range (800 to 2500 nm) compared to that of C-Si with polished surfaces, and the variations in the absorption spectra of the nanostructured black silicon with different etching processes are obtained. The maximum light absorptance increases significantly up to 95 % in the wavelength range of 400 to 2500 nm. Our recent novel results clearly indicate that nanostructured black silicon made by MCE has potential application in near-infrared photoelectronic detectors. PMID:27368764

  10. The Enhanced Light Absorptance and Device Application of Nanostructured Black Silicon Fabricated by Metal-assisted Chemical Etching

    NASA Astrophysics Data System (ADS)

    Zhong, Hao; Guo, Anran; Guo, Guohui; Li, Wei; Jiang, Yadong

    2016-07-01

    We use metal-assisted chemical etching (MCE) method to fabricate nanostructured black silicon on the surface of C-Si. The Si-PIN photoelectronic detector based on this type of black silicon shows excellent device performance with a responsivity of 0.57 A/W at 1060 nm. Silicon nanocone arrays can be created using MCE treatment. These modified surfaces show higher light absorptance in the near-infrared range (800 to 2500 nm) compared to that of C-Si with polished surfaces, and the variations in the absorption spectra of the nanostructured black silicon with different etching processes are obtained. The maximum light absorptance increases significantly up to 95 % in the wavelength range of 400 to 2500 nm. Our recent novel results clearly indicate that nanostructured black silicon made by MCE has potential application in near-infrared photoelectronic detectors.

  11. Semisynthetic DNA-protein conjugates for fabrication of nucleic acid based nanostructures

    NASA Astrophysics Data System (ADS)

    Rabe, Kersten S.; Feldkamp, Udo; Niemeyer, Christof M.

    2008-10-01

    We here report on the developments of semisynthetic DNA-protein conjugates and their assembly into multi-component nanostructures. We describe the improvement of the DNA sequences embedded in such nanostructures by computational and analytical methods. Moreover, we report on the exploration of novel DNA conjugates of streptavidin or redox proteins with improved properties for the assembly of nucleic acid based nanostructures.

  12. Fabrication and In vivo Thrombogenicity Testing of Nitric Oxide Generating Artificial Lungs

    PubMed Central

    Amoako, Kagya A; Montoya, Patrick J; Major, Terry C; Suhaib, Ahmed B; Handa, Hitesh; Brant, David O; Meyerhoff, Mark E; Bartlett, Robert H; Cook, Keith E

    2013-01-01

    Hollow fiber artificial lungs are increasingly being used for long-term applications. However, clot formation limits their use to 1-2 weeks. This study investigated the effect of nitric oxide generating (NOgen) hollow fibers on artificial lung thrombogenicity. Silicone hollow fibers were fabricated to incorporate 50 nm copper particles as a catalyst for NO generation from the blood. Fibers with and without (control) these particles were incorporated into artificial lungs with a 0.1 m2 surface area and inserted in circuits coated tip-to-tip with the NOgen material. Circuits (N=5/each) were attached to rabbits in a pumpless, arterio-venous configuration and run for 4 hrs at an activated clotting time of 350-400s. Three control circuits clotted completely, while none of the NOgen circuits failed. Accordingly, blood flows were significantly higher in the NOgen group (95.9 ± 11.7, p < 0.01) compared to the controls (35.2 ± 19.7) (ml/min), and resistance was significantly higher in the control group after 4 hours (15.38 ± 9.65, p<0.001) than in NOgen (0.09 ± 0.03) (mmHg/mL/min). On the other hand, platelet counts and plasma fibrinogen concentration expressed as percent of baseline in control group (63.7 ± 5.7%, 77.2 ± 5.6% [p<0.05]) were greater than those in the NOgen group (60.4 ± 5.1%, 63.2 ± 3.7%). Plasma copper levels in the NOgen group were 2.8 times baseline at 4 hours (132.8 ± 4.5 μg/dl) and unchanged in the controls. This work demonstrates that NO generating gas exchange fibers could be a potentially effective way to control coagulation inside artificial lungs. PMID:23613156

  13. Single-step direct fabrication of pillar-on-pore hybrid nanostructures in anodizing aluminum for superior superhydrophobic efficiency.

    PubMed

    Jeong, Chanyoung; Choi, Chang-Hwan

    2012-02-01

    Conventional electrochemical anodizing processes of metals such as aluminum typically produce planar and homogeneous nanopore structures. If hydrophobically treated, such 2D planar and interconnected pore structures typically result in lower contact angle and larger contact angle hysteresis than 3D disconnected pillar structures and, hence, exhibit inferior superhydrophobic efficiency. In this study, we demonstrate for the first time that the anodizing parameters can be engineered to design novel pillar-on-pore (POP) hybrid nanostructures directly in a simple one-step fabrication process so that superior surface superhydrophobicity can also be realized effectively from the electrochemical anodization process. On the basis of the characteristic of forming a self-ordered porous morphology in a hexagonal array, the modulation of anodizing voltage and duration enabled the formulation of the hybrid-type nanostructures having controlled pillar morphology on top of a porous layer in both mild and hard anodization modes. The hybrid nanostructures of the anodized metal oxide layer initially enhanced the surface hydrophilicity significantly (i.e., superhydrophilic). However, after a hydrophobic monolayer coating, such hybrid nanostructures then showed superior superhydrophobic nonwetting properties not attainable by the plain nanoporous surfaces produced by conventional anodization conditions. The well-regulated anodization process suggests that electrochemical anodizing can expand its usefulness and efficacy to render various metallic substrates with great superhydrophilicity or -hydrophobicity by directly realizing pillar-like structures on top of a self-ordered nanoporous array through a simple one-step fabrication procedure. PMID:22201335

  14. Direct-Write Fabrication of Cellulose Nano-Structures via Focused Electron Beam Induced Nanosynthesis

    PubMed Central

    Ganner, Thomas; Sattelkow, Jürgen; Rumpf, Bernhard; Eibinger, Manuel; Reishofer, David; Winkler, Robert; Nidetzky, Bernd; Spirk, Stefan; Plank, Harald

    2016-01-01

    In many areas of science and technology, patterned films and surfaces play a key role in engineering and development of advanced materials. Here, we introduce a new generic technique for the fabrication of polysaccharide nano-structures via focused electron beam induced conversion (FEBIC). For the proof of principle, organosoluble trimethylsilyl-cellulose (TMSC) thin films have been deposited by spin coating on SiO2 / Si and exposed to a nano-sized electron beam. It turns out that in the exposed areas an electron induced desilylation reaction takes place converting soluble TMSC to rather insoluble cellulose. After removal of the unexposed TMSC areas, structured cellulose patterns remain on the surface with FWHM line widths down to 70 nm. Systematic FEBIC parameter sweeps reveal a generally electron dose dependent behavior with three working regimes: incomplete conversion, ideal doses and over exposure. Direct (FT-IR) and indirect chemical analyses (enzymatic degradation) confirmed the cellulosic character of ideally converted areas. These investigations are complemented by a theoretical model which suggests a two-step reaction process by means of TMSC → cellulose and cellulose → non-cellulose material conversion in excellent agreement with experimental data. The extracted, individual reaction rates allowed the derivation of design rules for FEBIC parameters towards highest conversion efficiencies and highest lateral resolution. PMID:27585861

  15. Controllable fabrication of nanostructured materials for photoelectrochemical water splitting via atomic layer deposition.

    PubMed

    Wang, Tuo; Luo, Zhibin; Li, Chengcheng; Gong, Jinlong

    2014-11-21

    Photoelectrochemical (PEC) water splitting is an attractive approach to generate hydrogen as a clean chemical fuel from solar energy. But there remain many fundamental issues to be solved, including inadequate photon absorption, short carrier diffusion length, surface recombination, vulnerability to photo-corrosion, and unfavorable reaction kinetics. Owing to its self-limiting surface reaction mechanism, atomic layer deposition (ALD) is capable of depositing thin films in a highly controllable manner, which makes it an enabling technique to overcome some of the key challenges confronted by PEC water splitting. This tutorial review describes some unique and representative applications of ALD in fabricating high performance PEC electrodes with various nanostructures, including (i) coating conformal thin films on three-dimensional scaffolds to facilitate the separation and migration of photocarriers and enhance light trapping, as well as realizing controllable doping for bandgap engineering and forming homojunctions for carrier separation; (ii) achieving surface modification through deposition of anti-corrosion layers, surface state passivation layers, and surface catalytic layers; and (iii) identifying the main rate limiting steps with model electrodes with highly defined thickness, composition, and interfacial structure. PMID:24500041

  16. Up-scalable low-cost fabrication of plasmonic and photonic nanostructures for sensing

    NASA Astrophysics Data System (ADS)

    Gallinet, Benjamin; Davoine, Laurent; Basset, Guillaume; Schnieper, Marc

    2013-09-01

    The fabrication by nanoimprint lithography of large-area plasmonic and photonic sensing platforms is reported. The plasmonic nanostructures have the shape of split-ring resonators and support both electric dipole and quadrupole modes. They carry the spectral signature of Fano resonances. Their near-field and far-field optical properties are investigated with an analytical model together with numerical calculations. Fano-resonant systems combine strong nanoscale light confinement with a narrow spectral line width, which makes them very promising for biochemical sensing and immunoassays. On the other hand, chemical sensors based on resonant gratings are obtained by patterning a sol-gel material, evaporating a high refractive index semiconductor and coating with a chemically sensitive dye layer. By exposition to a liquid or an invisible gas such as ammonium, the change in absorption is detected optically. An analytical model is introduced to explain the enhancement of the signal by the resonant grating, which can be detected with the naked eye from a color change of the reflected light.

  17. Direct-Write Fabrication of Cellulose Nano-Structures via Focused Electron Beam Induced Nanosynthesis.

    PubMed

    Ganner, Thomas; Sattelkow, Jürgen; Rumpf, Bernhard; Eibinger, Manuel; Reishofer, David; Winkler, Robert; Nidetzky, Bernd; Spirk, Stefan; Plank, Harald

    2016-01-01

    In many areas of science and technology, patterned films and surfaces play a key role in engineering and development of advanced materials. Here, we introduce a new generic technique for the fabrication of polysaccharide nano-structures via focused electron beam induced conversion (FEBIC). For the proof of principle, organosoluble trimethylsilyl-cellulose (TMSC) thin films have been deposited by spin coating on SiO2 / Si and exposed to a nano-sized electron beam. It turns out that in the exposed areas an electron induced desilylation reaction takes place converting soluble TMSC to rather insoluble cellulose. After removal of the unexposed TMSC areas, structured cellulose patterns remain on the surface with FWHM line widths down to 70 nm. Systematic FEBIC parameter sweeps reveal a generally electron dose dependent behavior with three working regimes: incomplete conversion, ideal doses and over exposure. Direct (FT-IR) and indirect chemical analyses (enzymatic degradation) confirmed the cellulosic character of ideally converted areas. These investigations are complemented by a theoretical model which suggests a two-step reaction process by means of TMSC → cellulose and cellulose → non-cellulose material conversion in excellent agreement with experimental data. The extracted, individual reaction rates allowed the derivation of design rules for FEBIC parameters towards highest conversion efficiencies and highest lateral resolution. PMID:27585861

  18. On the magnetic properties of iron nanostructures fabricated via focused electron beam induced deposition and autocatalytic growth processes.

    PubMed

    Tu, F; Drost, M; Vollnhals, F; Späth, A; Carrasco, E; Fink, R H; Marbach, H

    2016-09-01

    We employ Electron beam induced deposition (EBID) in combination with autocatalytic growth (AG) processes to fabricate magnetic nanostructures with controllable shapes and thicknesses. Following this route, different Fe deposits were prepared on silicon nitride membranes under ultra-high vacuum conditions and studied by scanning electron microscopy (SEM) and scanning transmission x-ray microspectroscopy (STXM). The originally deposited Fe nanostructures are composed of pure iron, especially when fabricated via autocatalytic growth processes. Quantitative near-edge x-ray absorption fine structure (NEXAFS) spectroscopy was employed to derive information on the thickness dependent composition. X-ray magnetic circular dichroism (XMCD) in STXM was used to derive the magnetic properties of the EBID prepared structures. STXM and XMCD analysis evinces the existence of a thin iron oxide layer at the deposit-vacuum interface, which is formed during exposure to ambient conditions. We were able to extract magnetic hysteresis loops for individual deposits from XMCD micrographs with varying external magnetic field. Within the investigated thickness range (2-16 nm), the magnetic coercivity, as evaluated from the width of the hysteresis loops, increases with deposit thickness and reaches a maximum value of ∼160 Oe at around 10 nm. In summary, we present a viable technique to fabricate ferromagnetic nanostructures in a controllable way and gain detailed insight into their chemical and magnetic properties. PMID:27454990

  19. On the magnetic properties of iron nanostructures fabricated via focused electron beam induced deposition and autocatalytic growth processes

    NASA Astrophysics Data System (ADS)

    Tu, F.; Drost, M.; Vollnhals, F.; Späth, A.; Carrasco, E.; Fink, R. H.; Marbach, H.

    2016-09-01

    We employ Electron beam induced deposition (EBID) in combination with autocatalytic growth (AG) processes to fabricate magnetic nanostructures with controllable shapes and thicknesses. Following this route, different Fe deposits were prepared on silicon nitride membranes under ultra-high vacuum conditions and studied by scanning electron microscopy (SEM) and scanning transmission x-ray microspectroscopy (STXM). The originally deposited Fe nanostructures are composed of pure iron, especially when fabricated via autocatalytic growth processes. Quantitative near-edge x-ray absorption fine structure (NEXAFS) spectroscopy was employed to derive information on the thickness dependent composition. X-ray magnetic circular dichroism (XMCD) in STXM was used to derive the magnetic properties of the EBID prepared structures. STXM and XMCD analysis evinces the existence of a thin iron oxide layer at the deposit–vacuum interface, which is formed during exposure to ambient conditions. We were able to extract magnetic hysteresis loops for individual deposits from XMCD micrographs with varying external magnetic field. Within the investigated thickness range (2–16 nm), the magnetic coercivity, as evaluated from the width of the hysteresis loops, increases with deposit thickness and reaches a maximum value of ∼160 Oe at around 10 nm. In summary, we present a viable technique to fabricate ferromagnetic nanostructures in a controllable way and gain detailed insight into their chemical and magnetic properties.

  20. A simple and fast fabrication of a both self-cleanable and deep-UV antireflective quartz nanostructured surface

    PubMed Central

    2012-01-01

    Both self-cleanability and antireflectivity were achieved on quartz surfaces by forming heptadecafluoro-1,1,2,2-tetrahydrodecyltrichlorosilane self-assembled monolayer after fabrication of nanostructures with a mask-free method. By exposing polymethylmethacrylate spin-coated quartz plates to O2 reactive ion etching (RIE) and CF4 RIE successively, three well-defined types of nanopillar arrays were generated: A2, A8, and A11 patterns with average pillar widths of 33 ± 4 nm, 55 ± 5 nm, and 73 ± 14 nm, respectively, were formed. All the fabrication processes including the final cleaning can be finished within 4 h. All nanostructured quartz surfaces exhibited contact angles higher than 155° with minimal water droplet adhesiveness and enhanced transparency (due to antireflectivity) over a broad spectral range from 350 to 900 nm. Furthermore, A2 pattern showed an enhanced antireflective effect that extends to the deep-UV range near 190 nm, which is a drawback region in conventional thin-film-coating approaches as a result of thermal damage. Because, by changing the conditions of successive RIE, the geometrical configurations of nanostructure arrays can be easily modified to meet specific needs, the newly developed fabrication method is expected to be applied in various optic and opto-electrical areas. PACS codes: 06.60.Ei; 81.65.Cf; 81.40.Vw. PMID:22853428

  1. In Situ Fabrication of 3D Ag@ZnO Nanostructures for Microfluidic Surface-Enhanced Raman Scattering Systems

    PubMed Central

    2015-01-01

    In this work, we develop an in situ method to grow highly controllable, sensitive, three-dimensional (3D) surface-enhanced Raman scattering (SERS) substrates via an optothermal effect within microfluidic devices. Implementing this approach, we fabricate SERS substrates composed of Ag@ZnO structures at prescribed locations inside microfluidic channels, sites within which current fabrication of SERS structures has been arduous. Conveniently, properties of the 3D Ag@ZnO nanostructures such as length, packing density, and coverage can also be adjusted by tuning laser irradiation parameters. After exploring the fabrication of the 3D nanostructures, we demonstrate a SERS enhancement factor of up to ∼2 × 106 and investigate the optical properties of the 3D Ag@ZnO structures through finite-difference time-domain simulations. To illustrate the potential value of our technique, low concentrations of biomolecules in the liquid state are detected. Moreover, an integrated cell-trapping function of the 3D Ag@ZnO structures records the surface chemical fingerprint of a living cell. Overall, our optothermal-effect-based fabrication technique offers an effective combination of microfluidics with SERS, resolving problems associated with the fabrication of SERS substrates in microfluidic channels. With its advantages in functionality, simplicity, and sensitivity, the microfluidic-SERS platform presented should be valuable in many biological, biochemical, and biomedical applications. PMID:25402207

  2. One-step fabrication of nanostructure-covered microstructures using selective aluminum anodization based on non-uniform electric field

    NASA Astrophysics Data System (ADS)

    Park, Yong Min; Kim, Byeong Hee; Seo, Young Ho

    2016-06-01

    This paper presents a selective aluminum anodization technique for the fabrication of microstructures covered by nanoscale dome structures. It is possible to fabricate bulging microstructures, utilizing the different growth rates of anodic aluminum oxide in non-uniform electric fields, because the growth rate of anodic aluminum oxide depends on the intensity of electric field, or current density. After anodizing under a non-uniform electric field, bulging microstructures covered by nanostructures were fabricated by removing the residual aluminum layer. The non-uniform electric field induced by insulative micropatterns was estimated by computational simulations and verified experimentally. Utilizing computational simulations, the intensity profile of the electric field was calculated according to the ratio of height and width of the insulative micropatterns. To compare computational simulation results and experimental results, insulative micropatterns were fabricated using SU-8 photoresist. The results verified that the shape of the bottom topology of anodic alumina was strongly dependent on the intensity profile of the applied electric field, or current density. The one-step fabrication of nanostructure-covered microstructures can be applied to various fields, such as nano-biochip and nano-optics, owing to its simplicity and cost effectiveness.

  3. Fabrication, Light Emission, and Magnetism of Silica Nanoparticles Hybridized with AIE Luminogens and Inorganic Nanostructures

    NASA Astrophysics Data System (ADS)

    Faisal, Mahtab

    Much research efforts have been devoted in developing new synthetic approaches for fluorescent silica nanoparticles (FSNPs) due to their potential high-technological applications. However, light emissions from most of the FSNPs prepared so far have been rather weak. This is due to the emission quenching caused by the aggregation of fluorophores in the solid state. We have observed a novel phenomenon of aggregation-induced emission (AIE): a series of propeller-shaped molecules such as tetraphenylethene (TPE) and silole are induced to emit efficiently by aggregate formation. Thus, they are ideal fluorophors for the construction of FSNPs and my thesis work focuses on the synthesis of silica nanoparticles containing these luminogens and magnetic nanostructures. Highly emissive FSNPs with core-shell structures are fabricated by surfactant-free sol-gel reactions of tetraphenylethene- (TPE) and silole-functionalized siloxanes followed by the reactions with tetraethoxysilane. The FSNPs are uniformly sized, surface-charged and colloidally stable. The diameters of the FSNPs are tunable in the range of 45--295 nm by changing the reaction conditions. Whereas their TPE and silole precursors are non-emissive, the FSNPs emit strong visible lights, thanks to the novel aggregation-induced emission characteristics of the TPE and silole aggregates in the hybrid nanoparticles. The FSNPs pose no toxicity to living cells and can be utilized to selectively image cytoplasm of HeLa cells. Applying the same tool in the presence of citrate-coated magnetite nanoparticles, uniform magnetic fluorescent silica nanoparticles (MFSNPs) with smooth surfaces are fabricated. These particles exhibit appreciable surface charges and hence good colloidal stability. They are superparamagnetic, exhibiting no hysteresis at room temperature. UV irradiation of a suspension of MFSNPs in ethanol gives strong blue and green emissions. The MFSNPs can selectively stain the cytoplasmic regions of the living cells

  4. A new fabrication method for IPMC actuators and application to artificial fingers

    NASA Astrophysics Data System (ADS)

    Lee, Sang Jun; Han, Man Jae; Kim, Seong Jun; Jho, Jae Young; Lee, Ho Young; Hyup Kim, Yong

    2006-10-01

    IPMC (ionic polymer metal composite), a kind of ionic electroactive polymer (EAP), has been used for various applications because it has light weight and can make large bending deformation under low driving voltage. In the present work, thick IPMC films were fabricated by hot-pressing several thin IPMC films and the actuating performance was evaluated. Displacement and maximum load with applied voltage were measured using a displacement measuring system, a load cell and a multimeter. Several cycles of Pt electroless-plating were performed on the IPMC films to improve the actuating performance. Then, SEM (scanning electron microscopy) micrographs and EDS (energy dispersive spectrometer) profiles of the IPMC specimen were examined. To demonstrate the feasibility of IPMC films for medical or robotic applications, the developed IPMC actuators were applied to artificial fingers and tested.

  5. Egg-in-cube: design and fabrication of a novel artificial eggshell with functionalized surface.

    PubMed

    Huang, Wenjing; Arai, Fumihito; Kawahara, Tomohiro

    2015-01-01

    An eggshell is a porous microstructure that regulates the passage of gases to allow respiration. The chick embryo and its circulatory system enclosed by the eggshell has become an important model for biomedical research such as the control of angiogenesis, cancer therapy, and drug delivery test, because the use of embryo is ethically acceptable and it is inexpensive and small. However, chick embryo and extra-embryonic blood vessels cannot be accessed freely and has poor observability because the eggshell is tough and cannot be seen through, which limits its application. In this study, a novel artificial eggshell with functionalized surface is proposed, which allows the total amount of oxygen to pass into the egg for the chick embryo culturing and has high observability and accessibility for embryo manipulation. First, a 40-mm enclosed cubic-shaped eggshell consisting of a membrane structure and a rigid frame structure is designed, and then the threshold of the membrane thickness suitable for the embryo survival is figured out according to the oxygen-permeability of the membrane structure. The designed artificial eggshell was actually fabricated by using polydimethylsiloxane (PDMS) and polycarbonate (PC) in the current study. Using the fabricated eggshell, chick embryo and extra-embryonic blood vessels can be observed from multiple directions. To test the effectiveness of the design, the cubic eggshells were used to culture chick embryos and survivability was confirmed when PDMS membranes with adequate oxygen permeability were used. Since the surface of the eggshell is transparent, chick embryo tissue development could be observed during the culture period. Additionally, the chick embryo tissues could be accessed and manipulated from outside the cubic eggshell, by using mechanical tools without breakage of the eggshell. The proposed "Egg-in-Cube" with functionalized surface has great potential to serve as a promising platform for biomedical research. PMID:25768929

  6. Egg-in-Cube: Design and Fabrication of a Novel Artificial Eggshell with Functionalized Surface

    PubMed Central

    Huang, Wenjing; Arai, Fumihito; Kawahara, Tomohiro

    2015-01-01

    An eggshell is a porous microstructure that regulates the passage of gases to allow respiration. The chick embryo and its circulatory system enclosed by the eggshell has become an important model for biomedical research such as the control of angiogenesis, cancer therapy, and drug delivery test, because the use of embryo is ethically acceptable and it is inexpensive and small. However, chick embryo and extra-embryonic blood vessels cannot be accessed freely and has poor observability because the eggshell is tough and cannot be seen through, which limits its application. In this study, a novel artificial eggshell with functionalized surface is proposed, which allows the total amount of oxygen to pass into the egg for the chick embryo culturing and has high observability and accessibility for embryo manipulation. First, a 40-mm enclosed cubic-shaped eggshell consisting of a membrane structure and a rigid frame structure is designed, and then the threshold of the membrane thickness suitable for the embryo survival is figured out according to the oxygen-permeability of the membrane structure. The designed artificial eggshell was actually fabricated by using polydimethylsiloxane (PDMS) and polycarbonate (PC) in the current study. Using the fabricated eggshell, chick embryo and extra-embryonic blood vessels can be observed from multiple directions. To test the effectiveness of the design, the cubic eggshells were used to culture chick embryos and survivability was confirmed when PDMS membranes with adequate oxygen permeability were used. Since the surface of the eggshell is transparent, chick embryo tissue development could be observed during the culture period. Additionally, the chick embryo tissues could be accessed and manipulated from outside the cubic eggshell, by using mechanical tools without breakage of the eggshell. The proposed “Egg-in-Cube” with functionalized surface has great potential to serve as a promising platform for biomedical research. PMID

  7. Electrochemical template-assisted fabrication of CdS micro/nanostructures

    NASA Astrophysics Data System (ADS)

    Jindal, Zinki; Verma, N. K.

    2009-10-01

    One-dimensional (1D) cadmium sulphide (CdS) nanostructures, including micro/nanorods, and nanostructures resembling flowers and cactus have been synthesized by electrochemical template deposition technique, using polycarbonate membranes, by controlling various reaction parameters. These 1D CdS nanostructures were characterized structurally through the X-ray diffraction (XRD) studies and morphologically through scanning electron microscopy (SEM). It was found that apart from the dimensions of the pores of the templates, the geometrical morphologies of the CdS 1D nanostructures were significantly influenced by the synthesizing parameters also. The optical characterization has been done by UV-visible absorption and room-temperature photoluminescence (PL) studies.

  8. Fabrication of surface micro- and nanostructures for superhydrophobic surfaces in electric and electronic applications

    NASA Astrophysics Data System (ADS)

    Xiu, Yonghao

    our understanding of the roughness effect on superhydrophobicity (both contact angle and hysteresis), structured surfaces from polybutadiene, polyurethane, silica, and Si etc. were successfully prepared. For engineering applications of superhydrophobic surfaces, stability issues regarding UV, mechanical robustness and humid environment need to be investigated. Among these factors, UV stability is the first one to be studied. However, most polymer surfaces we prepared failed the purpose. Silica surfaces with excellent UV stability were prepared. This method consists of preparation of rough silica surfaces, thermal treatment and the following surface hydrophobization by fluoroalkyl silane treatment. Fluoroalkyl groups are UV stable and the underlying species are silica which is also UV stable (UV transparent). UV stability on the surface currently is 5,500 h according the standard test method of ASTM D 4329. No degradation on surface superhydrophobicity was observed. New methods for preparing superhydrophobic and transparent silica surfaces were investigated using urea-choline chloride eutectic liquid to generate fine roughness and reduce the cost for preparation of surface structures. Another possible application for self-cleaning in photovoltaic panels was investigated on Si surfaces by construction of the two-scale rough structures followed by fluoroalkyl silane treatment. Metal (Au) assisted etching was employed to fabricate nanostructures on micrometer pyramid surfaces. The light reflection on the prepared surfaces was investigated. After surface texturing using KOH etching for micrometer pyramids and the following nanostructure using metal assisted etching, surface light reflection reduced to a minimum value which shows that this surface texturing technique is highly promising for improving the photovoltaic efficiency while imparting photovoltaics the self-cleaning feature. This surface is also expected to be UV stable due to the same fluoroalkyl silane used

  9. Investigations on structural and multiferroic properties of artificially engineered lead zirconate titanate-cobalt iron oxide layered nanostructures

    NASA Astrophysics Data System (ADS)

    Ortega Achury, Nora Patricia

    Mutiferroics are a novel class of next generation multifunctional materials, which display simultaneous magnetic, electric, and ferroelastic ordering, have drawn increasing interest due to their multi-functionality for a variety of device applications. Since, very rare single phase materials exist in nature this kind of properties, an intensive research activity is being pursued towards the development of new engineered materials with strong magneto-electric (ME) coupling. In the present investigation, we have fabricated polycrystalline and highly oriented PbZr0.53,Ti0.47O3--CoFe 2O4 (PZT/CFO) artificially multilayers (MLs) engineered nanostructures thin films which were grown on Pt/TiO2/SiO2/Si and La 0.5Sr0.5CoO3 (LSCO) coated (001) MgO substrates respectively, using the pulsed laser deposition technique. The effect of various PZT/CFO sandwich configurations having 3, 5, and 9 layers, while maintaining similar total PZT and CFO thickness, has been systematically investigated. The first part of this thesis is devoted to the analysis of structural and microstructure properties of the PZT/CFO MLs. X-ray diffraction (XRD) and micro Raman analysis revealed that PZT and CFO were in the perovskite and spinel phases respectively in the all layered nanostructure, without any intermediate phase. The TEM and STEM line scan of the ML thin films showed that the layered structure was maintained with little inter-diffusion near the interfaces at nano-metric scale without any impurity phase, however better interface was observed in highly oriented films. Second part of this dissertation was dedicated to study of the dielectric, impedance, modulus, and conductivity spectroscopies. These measurements were carried out over a wide range of temperatures (100 K to 600 K) and frequencies (100 Hz to 1 MHz) to investigate the grain and grain boundary effects on electrical properties of MLs. The temperature dependent dielectric and loss tangent illustrated step-like behavior and

  10. Fabrication of nanostructured metal oxide films with supercritical carbon dioxide: Processing and applications

    NASA Astrophysics Data System (ADS)

    You, Eunyoung

    Nanostructured metal oxide films have many applications in catalysis, microelectronics, microfluidics, photovoltaics and other fields. Since the performance of a device depends greatly on the structure of the material, the development of methodologies that enable prescriptive control of morphology are of great interest. The focus of this work is to control the structure and properties of the nanostructured metal oxide films using novel synthetic schemes in supercritical fluids and to use those films as key building components in alternative energy applications. A supercritical fluid is a substance at a temperature and pressure above its critical point. It typically exhibits gas-like transport properties and liquid-like densities. Supercritical fluid deposition (SFD) utilizes these properties of supercritical CO2 (scCO2) to deposit chemically pure metal, oxides and alloys of metal films. SFD is a chemical vapor deposition (CVD)-like process in the sense that it uses similar metal organic precursors and deposits films at elevated temperatures. Instead of vaporizing or subliming the precursors, they are dissolved in supercritical fluids. SFD has typically shown to exhibit higher precursor concentrations, lower deposition temperatures, conformal deposition of films on high aspect ratio features as compared to CVD. In2 O3, ZnO and SnO2 are attractive materials because they are used in transparent conductors. SFD of these materials were studied and In2 O3 deposition kinetics using tris(2,2,6,6-tetramethyl-3,5-heptanedionato) In (III) as precursor were determined. Growth rate dependence on the deposition temperature and the precursor concentrations were studied and the physicochemical and optical properties of In2 O3 films were characterized. Metal oxide nanochannels that can potentially be used for microfluidics have been fabricated by sequentially performing nanoimprint lithography (NIL) and SFD. NIL was used to pattern photoresist grating on substrates and SFD of TiO2

  11. Nano-structure multilayer technology fabrication of high energy density capacitors for the power electronic building book

    SciTech Connect

    Barbee, T.W.; Johnson, G.W.; Wagner, A.V.

    1997-10-21

    Commercially available capacitors do not meet the specifications of the Power Electronic Building Block (PEBB) concept. We have applied our propriety nanostructure multilayer materials technology to the fabrication of high density capacitors designed to remove this impediment to PEBB progress. Our nanostructure multilayer capacitors will also be enabling technology in many industrial and military applications. Examples include transient suppression (snubber capacitors), resonant circuits, and DC filtering in PEBB modules. Additionally, weapon applications require compact energy storage for detonators and pulsed-power systems. Commercial applications run the gamut from computers to lighting to communications. Steady progress over the last five years has brought us to the threshold of commercial manufacturability. We have demonstrated a working dielectric energy density of > 11 J/cm3 in 20 nF devices designed for 1 kV operation.

  12. Fabrication and characterization of PbSe nanostructures on van der Waals surfaces of GaSe layered semiconductor crystals

    NASA Astrophysics Data System (ADS)

    Kudrynskyi, Z. R.; Bakhtinov, A. P.; Vodopyanov, V. N.; Kovalyuk, Z. D.; Tovarnitskii, M. V.; Lytvyn, O. S.

    2015-11-01

    The growth morphology, composition and structure of PbSe nanostructures grown on the atomically smooth, clean, nanoporous and oxidized van der Waals (0001) surfaces of GaSe layered crystals were studied by means of atomic force microscopy, x-ray diffractometry, photoelectron spectroscopy and Raman spectroscopy. Semiconductor heterostructures were grown by the hot-wall technique in vacuum. Nanoporous GaSe substrates were fabricated by the thermal annealing of layered crystals in a molecular hydrogen atmosphere. The irradiation of the GaSe(0001) surface by UV radiation was used to fabricate thin Ga2O3 layers with thickness < 2 nm. It was found that the narrow gap semiconductor PbSe shows a tendency to form clusters with a square or rectangular symmetry on the clean low-energy (0001) GaSe surface, and (001)-oriented growth of PbSe thin films takes place on this surface. Using this growth technique it is possible to grow PbSe nanostructures with different morphologies: continuous epitaxial layers with thickness < 10 nm on the uncontaminated p-GaSe(0001) surfaces, homogeneous arrays of quantum dots with a high lateral density (more than 1011 cm-2) on the oxidized van der Waals (0001) surfaces and faceted square pillar-like nanostructures with a low lateral density (˜108 cm-2) on the nanoporous GaSe substrates. We exploit the ‘vapor-liquid-solid’ growth with low-melting metal (Ga) catalyst of PbSe crystalline branched nanostructures via a surface-defect-assisted mechanism.

  13. Semiconductor Nanostructures for Solar Water Splitting and Hydrogen Production: Design, Growth/Fabrication, Characterization, and Device Performance

    NASA Astrophysics Data System (ADS)

    Kargar, Alireza

    Solar and seawater are the ultimate energy resources on earth, and together constitute a potential solution to the energy crisis, which at the same time can reduce the carbon emission due to the use of fossil fuels. However, there are challenges in the generation of hydrogen fuel through water splitting using solar energy, such as the cost, and large scale manufacturing of the efficient and durable photoelectrodes. Primary challenge for solar water splitting using photoelectrochemical (PEC) cells is to develop photoelectrodes with sufficient photovoltage to electrolyze water, with maximized photon utilization efficiency, with long lifetime, and with cheap cost. This thesis then focuses on design, characterization and fabrication of novel nanostructured heterojunctions (with focus on nanowire/nanorod array heterostructures) for solar water splitting and hydrogen production. The primary focus of this thesis is to develop such photoelectrodes using low-cost, earth-abundant, non-toxic materials with cheap, facile, scalable fabrication techniques for efficient and durable solar water splitting in neutral solutions. The formation of the nanostructured array heterojunction offers unique combination of desired properties, such as enhanced light absorption, improved charge separation/collection, enlarged reaction surface area, and better electrochemical reaction dynamics. Two different types of nanostructured array heterojunctions present in this thesis including (i) Si/metal-oxides nanowire array heterojunction photoelectrodes (chapters 2-6), and (ii) all-metal-oxides nanowire/nanorod heterostructure photoelectrodes (chapters 7-8). Two different catalysts for hydrogen or oxygen evolution reaction are presented in chapters 9-10. The application of catalyst is to facilitate the gas evolution on the surface of nanostructured heterojunctions to improve the solar hydrogen production efficiency.

  14. In situ fabricate Cu{sub 2}S thin film with hierarchical petal-like nanostructures

    SciTech Connect

    Li, Jing; Zhao, Hongxiao Chen, Xinhua; Jia, Huimin; Zheng, Zhi

    2013-08-01

    Graphical abstract: - Highlights: • Cu{sub 2}S thin films with hierarchical nanostructures have been synthesized by solvothermal method using DMSO as reactant. • The band gap is estimated to be 1.0 eV of the Cu{sub 2}S hierarchical nanostructures. • The form process of Cu{sub 2}S and the possible mechanism of hierarchical nanostructures were proposed. - Abstract: In this paper, Cu{sub 2}S thin film with hierarchical petal-like nanostructures has been successfully in situ synthesized via a solvothermal method using DMSO as reactant under appropriate reaction conditions. The crystalline phase, morphology and optical properties of the resulting products were characterized by X-ray diffraction, energy-dispersive X-ray spectrometry, scanning electron microscopy and UV–vis absorption spectroscopy, respectively. The band gap is estimated to be about 1.0 eV by the results of UV–vis absorption spectroscopy of the Cu{sub 2}S thin film with hierarchical nanostructures that consisted of nanoslices with the thickness of 15 nm. The formation process of Cu{sub 2}S and the possible mechanism of hierarchical nanostructures were also proposed. These findings are valuable since Cu{sub 2}S thin film with hierarchical petal-like nanostructures are promising candidate as lithium ion battery and solar cell materials.

  15. A simple method for fabricating artificial kidney stones of different physical properties

    PubMed Central

    Esch, Eric; Simmons, W. Neal; Sankin, Georgy; Cocks, Hadley F.; Preminger, Glenn M.; Zhong, Pei

    2013-01-01

    A simple method for preparing artificial kidney stones with varying physical properties is described. BegoStone was prepared with a powder to water ratio (by weight) ranging from 15:3 to 15:6. The acoustic properties of the phantoms were characterized by using an ultrasound transmission technique, from which the corresponding mechanical properties were calculated based on elastic wave theory. The measured parameters for BegoStone phantoms of different water contents are: longitudinal wave speed (3148 – 4159 m/s), transverse wave speed (1813 – 2319 m/s), density (1563 – 1995 kg/m3), longitudinal acoustic impedance (4.92 – 8.30 Kg/m2*s), transverse acoustic impedance (2.83 – 4.63 Kg/m2*s), Young’s modulus (12.9 – 27.4 GPa), bulk modulus (8.6 – 20.2 GPa), and shear modulus (5.1 – 10.7 GPa), which cover the range of corresponding properties reported in natural kidney stones. In addition, diametral compression tests were carried out to determine tensile failure strength of the stone phantoms. BegoStone phantoms with varying water content at preparation have tensile failure strength from 6.9 – 16.3 MPa when tested dry and 3.2 – 7.1 MPa when tested in water-soaked condition. Overall, it is demonstrated that this new BegoStone preparation method can be used to fabricate artificial stones with physical properties matched with those of natural kidney stones of various chemical compositions. PMID:20652562

  16. A simple method for fabricating artificial kidney stones of different physical properties.

    PubMed

    Esch, Eric; Simmons, Walter Neal; Sankin, Georgy; Cocks, Hadley F; Preminger, Glenn M; Zhong, Pei

    2010-08-01

    A simple method for preparing artificial kidney stones with varying physical properties is described. BegoStone was prepared with a powder-to-water ratio ranging from 15:3 to 15:6. The acoustic properties of the phantoms were characterized using an ultrasound transmission technique, from which the corresponding mechanical properties were calculated based on elastic wave theory. The measured parameters for BegoStone phantoms of different water contents are: longitudinal wave speed (3,148-4,159 m/s), transverse wave speed (1,813-2,319 m/s), density (1,563-1,995 kg/m(3)), longitudinal acoustic impedance (4.92-8.30 kg/m(2) s), transverse acoustic impedance (2.83-4.63 kg/m(2) s), Young's modulus (12.9-27.4 GPa), bulk modulus (8.6-20.2 GPa), and shear modulus (5.1-10.7 GPa), which cover the range of corresponding properties reported in natural kidney stones. In addition, diametral compression tests were carried out to determine tensile failure strength of the stone phantoms. BegoStone phantoms with varying water content at preparation have tensile failure strength from 6.9 to 16.3 MPa when tested dry and 3.2 to 7.1 MPa when tested in water-soaked condition. Overall, it is demonstrated that this new BegoStone preparation method can be used to fabricate artificial stones with physical properties matched with those of natural kidney stones of various chemical compositions. PMID:20652562

  17. From Artificial Atoms to Nanocrystal Molecules: Preparation and Properties of More Complex Nanostructures

    SciTech Connect

    Choi, Charina L; Alivisatos, A Paul

    2009-10-20

    Quantum dots, which have found widespread use in fields such as biomedicine, photovoltaics, and electronics, are often called artificial atoms due to their size-dependent physical properties. Here this analogy is extended to consider artificial nanocrystal molecules, formed from well-defined groupings of plasmonically or electronically coupled single nanocrystals. Just as a hydrogen molecule has properties distinct from two uncoupled hydrogen atoms, a key feature of nanocrystal molecules is that they exhibit properties altered from those of the component nanoparticles due to coupling. The nature of the coupling between nanocrystal atoms and its response to vibrations and deformations of the nanocrystal molecule bonds are of particular interest. We discuss synthetic approaches, predicted and observed physical properties, and prospects and challenges toward this new class of materials.

  18. Reliable contact fabrication on nanostructured Bi2Te3-based thermoelectric materials.

    PubMed

    Feng, Shien-Ping; Chang, Ya-Huei; Yang, Jian; Poudel, Bed; Yu, Bo; Ren, Zhifeng; Chen, Gang

    2013-05-14

    A cost-effective and reliable Ni-Au contact on nanostructured Bi2Te3-based alloys for a solar thermoelectric generator (STEG) is reported. The use of MPS SAMs creates a strong covalent binding and more nucleation sites with even distribution for electroplating contact electrodes on nanostructured thermoelectric materials. A reliable high-performance flat-panel STEG can be obtained by using this new method. PMID:23531997

  19. Fabrication of nanostructured targets for improved laser-driven proton acceleration

    NASA Astrophysics Data System (ADS)

    Barberio, M.; Scisciò, M.; Veltri, S.; Antici, P.

    2016-07-01

    In this work, we present a novel realization of nanostructured targets suitable for improving laser-driven proton acceleration experiments, in particular with regard to the Target-Normal-Sheath Acceleration (TNSA) acceleration mechanism. The nanostructured targets, produced as films, are realized by a simpler and cheaper method than using conventional lithographic techniques. The growth process includes a two step approach for the production of the gold nanoparticle layers: 1) Laser Ablation in Solution and 2) spray-dry technique using a colloidal solution on target surfaces (Aluminum, Mylar and Multi Walled Carbon Nanotube). The obtained nanostructured films appear, at morphological and chemical analysis, uniformly nanostructured and the nanostructure distributed on the target surfaces without presence of oxides or external contaminants. The obtained targets show a broad optical absorption in all the visible region and a surface roughness that is two times greater than non-nanostructured targets, enabling a greater laser energy absorption during the laser-matter interaction experiments producing the laser-driven proton acceleration.

  20. Adhesive strength of medical polymer on anodic oxide nanostructures fabricated on biomedical β-type titanium alloy.

    PubMed

    Hieda, Junko; Niinomi, Mitsuo; Nakai, Masaaki; Cho, Ken; Mohri, Tomoyoshi; Hanawa, Takao

    2014-03-01

    Anodic oxide nanostructures (nanopores and nanotubes) were fabricated on a biomedical β-type titanium alloy, Ti-29Nb-13Ta-4.6Zr alloy (TNTZ), by anodization in order to improve the adhesive strength of a medical polymer, segmented polyurethane (SPU), to TNTZ. TNTZ was anodized in 1.0M H3PO4 solution with 0.5 mass% NaF using a direct-current power supply at a voltage of 20V. A nanoporous structure is formed on TNTZ in the first stage of anodization, and the formation of a nanotube structure occurs subsequently beneath the nanoporous structure. The nanostructures formed on TNTZ by anodization for less than 3,600s exhibit higher adhesive strengths than those formed at longer anodization times. The adhesive strength of the SPU coating on the nanoporous structure formed on top of TNTZ by anodization for 1,200s improves by 144% compared to that of the SPU coating on as-polished TNTZ with a mirror surface. The adhesive strength of the SPU coating on the nanotube structure formed on TNTZ by anodization for 3,600s increases by 50%. These improvements in the adhesive strength of SPU are the result of an anchor effect introduced by the nanostructures formed by anodization. Fracture occurs at the interface of the nanoporous structure and the SPU coating layer. In contrast, in the case that SPU coating has been performed on the nanotube structure, fracture occurs inside the nanotubes. PMID:24433910

  1. Trace detection of herbicides by SERS technique, using SERS-active substrates fabricated from different silver nanostructures deposited on silicon

    NASA Astrophysics Data System (ADS)

    Cao Dao, Tran; Quynh Ngan Luong, Truc; Cao, Tuan Anh; Hai Nguyen, Ngoc; Kieu, Ngoc Minh; Thuy Luong, Thi; Le, Van Vu

    2015-09-01

    In this report we present the initial results of the use of different silver nanostructures deposited on silicon for trace detection of paraquat (a commonly used herbicide) using the surface-enhanced Raman scattering (SERS) effect. More specifically, the SERS-active substrates were fabricated from silver nanoparticles (AgNPs) deposited onto the flat surface of a silicon wafer (AgNPs@Si substrate), as well as on the surface of an obliquely aligned silicon nanowire (SiNW) array (AgNPs@SiNWs substrate), and from silver nanodendrites (AgNDs) deposited onto the flat surface of a silicon wafer (AgNDs@Si substrate). Results showed that with the change of the structure of the SERS-active substrate, higher levels of SERS enhancement have been achieved. Specifically, with the fabricated AgNDs@Si substrate, paraquat concentration as low as 1 ppm can be detected.

  2. Integrating Nanostructured Artificial Receptors with Whispering Gallery Mode Optical Microresonators via Inorganic Molecular Imprinting Techniques.

    PubMed

    Hammond, G Denise; Vojta, Adam L; Grant, Sheila A; Hunt, Heather K

    2016-01-01

    The creation of label-free biosensors capable of accurately detecting trace contaminants, particularly small organic molecules, is of significant interest for applications in environmental monitoring. This is achieved by pairing a high-sensitivity signal transducer with a biorecognition element that imparts selectivity towards the compound of interest. However, many environmental pollutants do not have corresponding biorecognition elements. Fortunately, biomimetic chemistries, such as molecular imprinting, allow for the design of artificial receptors with very high selectivity for the target. Here, we perform a proof-of-concept study to show how artificial receptors may be created from inorganic silanes using the molecular imprinting technique and paired with high-sensitivity transducers without loss of device performance. Silica microsphere Whispering Gallery Mode optical microresonators are coated with a silica thin film templated by a small fluorescent dye, fluorescein isothiocyanate, which serves as our model target. Oxygen plasma degradation and solvent extraction of the template are compared. Extracted optical devices are interacted with the template molecule to confirm successful sorption of the template. Surface characterization is accomplished via fluorescence and optical microscopy, ellipsometry, optical profilometry, and contact angle measurements. The quality factors of the devices are measured to evaluate the impact of the coating on device sensitivity. The resulting devices show uniform surface coating with no microstructural damage with Q factors above 10⁶. This is the first report demonstrating the integration of these devices with molecular imprinting techniques, and could lead to new routes to biosensor creation for environmental monitoring. PMID:27314397

  3. Integrating Nanostructured Artificial Receptors with Whispering Gallery Mode Optical Microresonators via Inorganic Molecular Imprinting Techniques

    PubMed Central

    Hammond, G. Denise; Vojta, Adam L.; Grant, Sheila A.; Hunt, Heather K.

    2016-01-01

    The creation of label-free biosensors capable of accurately detecting trace contaminants, particularly small organic molecules, is of significant interest for applications in environmental monitoring. This is achieved by pairing a high-sensitivity signal transducer with a biorecognition element that imparts selectivity towards the compound of interest. However, many environmental pollutants do not have corresponding biorecognition elements. Fortunately, biomimetic chemistries, such as molecular imprinting, allow for the design of artificial receptors with very high selectivity for the target. Here, we perform a proof-of-concept study to show how artificial receptors may be created from inorganic silanes using the molecular imprinting technique and paired with high-sensitivity transducers without loss of device performance. Silica microsphere Whispering Gallery Mode optical microresonators are coated with a silica thin film templated by a small fluorescent dye, fluorescein isothiocyanate, which serves as our model target. Oxygen plasma degradation and solvent extraction of the template are compared. Extracted optical devices are interacted with the template molecule to confirm successful sorption of the template. Surface characterization is accomplished via fluorescence and optical microscopy, ellipsometry, optical profilometry, and contact angle measurements. The quality factors of the devices are measured to evaluate the impact of the coating on device sensitivity. The resulting devices show uniform surface coating with no microstructural damage with Q factors above 106. This is the first report demonstrating the integration of these devices with molecular imprinting techniques, and could lead to new routes to biosensor creation for environmental monitoring. PMID:27314397

  4. Precisely controlled resorcinol-formaldehyde resin coating for fabricating core-shell, hollow, and yolk-shell carbon nanostructures

    NASA Astrophysics Data System (ADS)

    Fang, Xiaoliang; Liu, Shengjie; Zang, Jun; Xu, Chaofa; Zheng, Ming-Sen; Dong, Quan-Feng; Sun, Daohua; Zheng, Nanfeng

    2013-07-01

    This work provides a facile one-step sol-gel route to synthesize high-quality resorcinol-formaldehyde (RF) resin coated nanocomposites that can be further used to fabricate desired carbon nanostructures. Colloidal particles with different morphologies and sizes can be coated with high-quality RF resin shells by the proposed cationic surfactant assisted RF resin coating strategy. The as-synthesized RF resin coated nanocomposites are ideal candidates for selective synthesis of core-shell, hollow, and yolk-shell carbon nanostructures. Based on the carboxylic functional RF resin coating, graphitic carbon nanostructures can also be synthesized by employing the graphitization catalyst. The as-synthesized carbon nanostructures show the advantageous performances in several applications. Hollow carbon spheres are potential electrode materials for lithium-sulfur batteries. Hollow graphitic spheres are promising catalyst supports for oxygen reduction reaction. And yolk-shell structured Au@HCS nanoreactors with ultrathin shells exhibit high catalytic activity and recyclability in confined catalysis.This work provides a facile one-step sol-gel route to synthesize high-quality resorcinol-formaldehyde (RF) resin coated nanocomposites that can be further used to fabricate desired carbon nanostructures. Colloidal particles with different morphologies and sizes can be coated with high-quality RF resin shells by the proposed cationic surfactant assisted RF resin coating strategy. The as-synthesized RF resin coated nanocomposites are ideal candidates for selective synthesis of core-shell, hollow, and yolk-shell carbon nanostructures. Based on the carboxylic functional RF resin coating, graphitic carbon nanostructures can also be synthesized by employing the graphitization catalyst. The as-synthesized carbon nanostructures show the advantageous performances in several applications. Hollow carbon spheres are potential electrode materials for lithium-sulfur batteries. Hollow graphitic

  5. Ionic pH and glucose sensors fabricated using hydrothermal ZnO nanostructures

    NASA Astrophysics Data System (ADS)

    Wang, Jyh-Liang; Yang, Po-Yu; Hsieh, Tsang-Yen; Juan, Pi-Chun

    2016-01-01

    Hydrothermally synthesized aluminum-doped ZnO (AZO) nanostructures have been adopted in extended-gate field-effect transistor (EGFET) sensors to demonstrate the sensitive and stable pH and glucose sensing characteristics of AZO-nanostructured EGFET sensors. The AZO-nanostructured EGFET sensors exhibited the following superior pH sensing characteristics: a high current sensitivity of 0.96 µA1/2/pH, a high linearity of 0.9999, less distortion of output waveforms, a small hysteresis width of 4.83 mV, good long-term repeatability, and a wide sensing range from pHs 1 to 13. The glucose sensing characteristics of AZO-nanostructured biosensors exhibited the desired sensitivity of 60.5 µA·cm-2·mM-1 and a linearity of 0.9996 up to 13.9 mM. The attractive characteristics of high sensitivity, high linearity, and repeatability of using ionic AZO-nanostructured EGFET sensors indicate their potential use as electrochemical and disposable biosensors.

  6. Aqueous-Based Fabrication of Low-VOC Nanostructured Block Copolymer Films as Potential Marine Antifouling Coatings.

    PubMed

    Kim, Kris S; Gunari, Nikhil; MacNeil, Drew; Finlay, John; Callow, Maureen; Callow, James; Walker, Gilbert C

    2016-08-10

    The ability to fabricate nanostructured films by exploiting the phenomenon of microphase separation has made block copolymers an invaluable tool for a wide array of coating applications. Standard approaches to engineering nanodomains commonly involve the application of organic solvents, either through dissolution or annealing protocols, resulting in the release of volatile organic compounds (VOCs). In this paper, an aqueous-based method of fabricating low-VOC nanostructured block copolymer films is presented. The reported procedure allows for the phase transfer of water insoluble triblock copolymer, poly(styrene-block-2 vinylpyridine-block-ethylene oxide) (PS-b-P2VP-b-PEO), from a water immiscible phase to an aqueous environment with the assistance of a diblock copolymeric phase transfer agent, poly(styrene-block-ethylene oxide) (PS-b-PEO). Phase transfer into the aqueous phase results in self-assembly of PS-b-P2VP-b-PEO into core-shell-corona micelles, which are characterized by dynamic light scattering techniques. The films that result from coating the micellar solution onto Si/SiO2 surfaces exhibit nanoscale features that disrupt the ability of a model foulant, a zoospore of Ulva linza, to settle. The multilayered architecture consists of a pH-responsive P2VP-"shell" which can be stimulated to control the size of these features. The ability of these nanostructured thin films to resist protein adsorption and serve as potential marine antifouling coatings is supported through atomic force microscopy (AFM) and analysis of the settlement of Ulva linza zoospore. Field trials of the surfaces in a natural environment show the inhibition of macrofoulants for 1 month. PMID:27388921

  7. Low-cost fabrication technologies for nanostructures: state-of-the-art and potential

    NASA Astrophysics Data System (ADS)

    Santos, A.; Deen, M. J.; Marsal, L. F.

    2015-01-01

    In the last decade, some low-cost nanofabrication technologies used in several disciplines of nanotechnology have demonstrated promising results in terms of versatility and scalability for producing innovative nanostructures. While conventional nanofabrication technologies such as photolithography are and will be an important part of nanofabrication, some low-cost nanofabrication technologies have demonstrated outstanding capabilities for large-scale production, providing high throughputs with acceptable resolution and broad versatility. Some of these nanotechnological approaches are reviewed in this article, providing information about the fundamentals, limitations and potential future developments towards nanofabrication processes capable of producing a broad range of nanostructures. Furthermore, in many cases, these low-cost nanofabrication approaches can be combined with traditional nanofabrication technologies. This combination is considered a promising way of generating innovative nanostructures suitable for a broad range of applications such as in opto-electronics, nano-electronics, photonics, sensing, biotechnology or medicine.

  8. Low-cost fabrication technologies for nanostructures: state-of-the-art and potential.

    PubMed

    Santos, A; Deen, M J; Marsal, L F

    2015-01-30

    In the last decade, some low-cost nanofabrication technologies used in several disciplines of nanotechnology have demonstrated promising results in terms of versatility and scalability for producing innovative nanostructures. While conventional nanofabrication technologies such as photolithography are and will be an important part of nanofabrication, some low-cost nanofabrication technologies have demonstrated outstanding capabilities for large-scale production, providing high throughputs with acceptable resolution and broad versatility. Some of these nanotechnological approaches are reviewed in this article, providing information about the fundamentals, limitations and potential future developments towards nanofabrication processes capable of producing a broad range of nanostructures. Furthermore, in many cases, these low-cost nanofabrication approaches can be combined with traditional nanofabrication technologies. This combination is considered a promising way of generating innovative nanostructures suitable for a broad range of applications such as in opto-electronics, nano-electronics, photonics, sensing, biotechnology or medicine. PMID:25567484

  9. Fabrication of flower-like silver nanostructure on the Al substrate for surface enhanced fluorescence

    NASA Astrophysics Data System (ADS)

    Dong, Jun; Zheng, Hairong; Yan, Xiaoqing; Sun, Yu; Zhang, Zhenglong

    2012-01-01

    Surface-enhanced fluorescence (SEF) substrates consisting of flower-like nanostructure of electromagnetically coupled silver dendrites on Al surface were manufactured by modified galvanic displacement process between Ag ion and Al at room temperature. Substrate enhancement efficiency, which was evaluated from SEF intensities of the adsorbed Rhodamine 6 G(Rh6G), was found to increase rapidly with reaction time. The observation highlights the importance of strong coupling effects between nanobranches in SEF. The variation of SEF efficiency can be qualitatively explained with local surface plasmon resonance model of coupled silver nanostructures.

  10. Fabrication and development of artificial osteochondral constructs based on cancellous bone/hydrogel hybrid scaffold.

    PubMed

    Song, Kedong; Li, Liying; Yan, Xinyu; Zhang, Yu; Li, Ruipeng; Wang, Yiwei; Wang, Ling; Wang, Hong; Liu, Tianqing

    2016-06-01

    Using tissue engineering techniques, an artificial osteochondral construct was successfully fabricated to treat large osteochondral defects. In this study, porcine cancellous bones and chitosan/gelatin hydrogel scaffolds were used as substitutes to mimic bone and cartilage, respectively. The porosity and distribution of pore size in porcine bone was measured and the degradation ratio and swelling ratio for chitosan/gelatin hydrogel scaffolds was also determined in vitro. Surface morphology was analyzed with the scanning electron microscope (SEM). The physicochemical properties and the composition were tested by using an infrared instrument. A double layer composite scaffold was constructed via seeding adipose-derived stem cells (ADSCs) induced to chondrocytes and osteoblasts, followed by inoculation in cancellous bones and hydrogel scaffolds. Cell proliferation was assessed through Dead/Live staining and cellular activity was analyzed with IpWin5 software. Cell growth, adhesion and formation of extracellular matrix in composite scaffolds blank cancellous bones or hydrogel scaffolds were also analyzed. SEM analysis revealed a super porous internal structure of cancellous bone scaffolds and pore size was measured at an average of 410 ± 59 μm while porosity was recorded at 70.6 ± 1.7 %. In the hydrogel scaffold, the average pore size was measured at 117 ± 21 μm and the porosity and swelling rate were recorded at 83.4 ± 0.8 % and 362.0 ± 2.4 %, respectively. Furthermore, the remaining hydrogel weighed 80.76 ± 1.6 % of the original dry weight after hydration in PBS for 6 weeks. In summary, the cancellous bone and hydrogel composite scaffold is a promising biomaterial which shows an essential physical performance and strength with excellent osteochondral tissue interaction in situ. ADSCs are a suitable cell source for osteochondral composite reconstruction. Moreover, the bi-layered scaffold significantly enhanced cell proliferation compared to the cells seeded on

  11. Fabrication of Smart Chemical Sensors Based on Transition-Doped-Semiconductor Nanostructure Materials with µ-Chips

    PubMed Central

    Rahman, Mohammed M.; Khan, Sher Bahadar; Asiri, Abdullah M.

    2014-01-01

    Transition metal doped semiconductor nanostructure materials (Sb2O3 doped ZnO microflowers, MFs) are deposited onto tiny µ-chip (surface area, ∼0.02217 cm2) to fabricate a smart chemical sensor for toxic ethanol in phosphate buffer solution (0.1 M PBS). The fabricated chemi-sensor is also exhibited higher sensitivity, large-dynamic concentration ranges, long-term stability, and improved electrochemical performances towards ethanol. The calibration plot is linear (r2 = 0.9989) over the large ethanol concentration ranges (0.17 mM to 0.85 M). The sensitivity and detection limit is ∼5.845 µAcm−2mM−1 and ∼0.11±0.02 mM (signal-to-noise ratio, at a SNR of 3) respectively. Here, doped MFs are prepared by a wet-chemical process using reducing agents in alkaline medium, which characterized by UV/vis., FT-IR, Raman, X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), and field-emission scanning electron microscopy (FE-SEM) etc. The fabricated ethanol chemical sensor using Sb2O3-ZnO MFs is simple, reliable, low-sample volume (<70.0 µL), easy of integration, high sensitivity, and excellent stability for the fabrication of efficient I–V sensors on μ-chips. PMID:24454785

  12. Tunable top-down fabrication and functional surface coating of single-crystal titanium dioxide nanostructures and nanoparticles.

    PubMed

    Ha, Seungkyu; Janissen, Richard; Ussembayev, Yera Ye; van Oene, Maarten M; Solano, Belen; Dekker, Nynke H

    2016-05-19

    Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile TiO2 nanocylinders tethered with individual DNA molecules for use as force- and torque-transducers in an optical torque wrench. These developments provide the means for increased exploitation of the superior material properties of single-crystal TiO2 at the nanoscale. PMID:27160731

  13. Superhydrophilic nanostructure

    DOEpatents

    Mao, Samuel S; Zormpa, Vasileia; Chen, Xiaobo

    2015-05-12

    An embodiment of a superhydrophilic nanostructure includes nanoparticles. The nanoparticles are formed into porous clusters. The porous clusters are formed into aggregate clusters. An embodiment of an article of manufacture includes the superhydrophilic nanostructure on a substrate. An embodiment of a method of fabricating a superhydrophilic nanostructure includes applying a solution that includes nanoparticles to a substrate. The substrate is heated to form aggregate clusters of porous clusters of the nanoparticles.

  14. Fabrication of chondroitin sulfate-chitosan composite artificial extracellular matrix for stabilization of fibroblast growth factor.

    PubMed

    Mi, Fwu-Long; Shyu, Shin-Shing; Peng, Chih-Kang; Wu, Yu-Bey; Sung, Hsing-Wen; Wang, Pei-Shan; Huang, Chi-Chuan

    2006-01-01

    The development of a novel, three-dimensional, macroporous artificial extracellular matrix (AECM) based on chondroitin sulfate (ChS)-chitosan (Chito) combination is reported. The composite AECM composed of ChS-Chito conjugated network was prepared by a homogenizing interpolyelectrolyte complex/covalent conjugation technique through co-crosslinked with N,N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide (EDC) and N-hydroxysuccinimide (NHS). In contrast to EDC/NHS, two different reagents, calcium ion and glutaraldehyde, were used to react with ChS or Chito for the preparation of ChS-Chito composites containing crosslinked ChS or Chito network in the matrix. The stability and in vitro enzymatic degradability of the glutaraldehyde-, EDC/NHS-, and Ca2+ -crosslinked ChS-Chito composite AECMs were all investigated in this study. The results showed that crosslinking improved the stability of prepared ChS-Chito AECMs in physiological buffer solution (PBS) and provided superior protective effect against the enzymatic hydrolysis of ChS, compared with their non-crosslinked counterpart. Because ChS was a heparin-like glycosaminoglycan (GAG), the ChS-Chito composite AECMs appeared to promote binding efficiency for basic fibroblast growth factor (bFGF). The bFGF releasing from the ChS-Chito composite AECMs retained its biological activity as examined by the in vitro proliferation of human fibroblast, depending on the crosslinking mode for the preparation of these composite AECMs. Histological assay showed that the EDC/NHS-crosslinked ChS-Chito composite AECM, after incorporated with bFGF, was biodegradable and could result in a significantly enhanced vascularization effect and tissue penetration. These results suggest that the ChS-Chito composite AECMs fabricated in this study may be a promising approach for tissue-engineering application. PMID:16224775

  15. Fabrication of ferroelectric polymer nanostructures on flexible substrates by soft-mold reverse nanoimprint lithography.

    PubMed

    Song, Jingfeng; Lu, Haidong; Li, Shumin; Tan, Li; Gruverman, Alexei; Ducharme, Stephen

    2016-01-01

    Conventional nanoimprint lithography with expensive rigid molds is used to pattern ferroelectric polymer nanostructures on hard substrate for use in, e.g., organic electronics. The main innovation here is the use of inexpensive soft polycarbonate molds derived from recordable DVDs and reverse nanoimprint lithography at low pressure, which is compatible with flexible substrates. This approach was implemented to produce regular stripe arrays with a spacing of 700 nm from vinylidene fluoride co trifluoroethylene ferroelectric copolymer on flexible polyethylene terephthalate substrates. The nanostructures have very stable and switchable piezoelectric response and good crystallinity, and are highly promising for use in organic electronics enhanced or complemented by the unique properties of the ferroelectric polymer, such as bistable polarization, piezoelectric response, pyroelectric response, or electrocaloric function. The soft-mold reverse nanoimprint lithography also leaves little or no residual layer, affording good isolation of the nanostructures. This approach reduces the cost and facilitates large-area, high-throughput production of isolated functional polymer nanostructures on flexible substrates for the increasing application of ferroelectric polymers in flexible electronics. PMID:26597076

  16. Transformational, Large Area Fabrication of Nanostructured Materials Using Plasma Arc Lamps

    SciTech Connect

    2009-03-01

    This factsheet describes a study that will address critical additional steps over large areas of as-synthesized nanostructured materials, such as annealing, phase transformation, or activation of dopants, dramatically reducing the processing costs of the solid-state lighting and photovoltaic materials.

  17. Fabrication of ferroelectric polymer nanostructures on flexible substrates by soft-mold reverse nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Song, Jingfeng; Lu, Haidong; Li, Shumin; Tan, Li; Gruverman, Alexei; Ducharme, Stephen

    2016-01-01

    Conventional nanoimprint lithography with expensive rigid molds is used to pattern ferroelectric polymer nanostructures on hard substrate for use in, e.g., organic electronics. The main innovation here is the use of inexpensive soft polycarbonate molds derived from recordable DVDs and reverse nanoimprint lithography at low pressure, which is compatible with flexible substrates. This approach was implemented to produce regular stripe arrays with a spacing of 700 nm from vinylidene fluoride co trifluoroethylene ferroelectric copolymer on flexible polyethylene terephthalate substrates. The nanostructures have very stable and switchable piezoelectric response and good crystallinity, and are highly promising for use in organic electronics enhanced or complemented by the unique properties of the ferroelectric polymer, such as bistable polarization, piezoelectric response, pyroelectric response, or electrocaloric function. The soft-mold reverse nanoimprint lithography also leaves little or no residual layer, affording good isolation of the nanostructures. This approach reduces the cost and facilitates large-area, high-throughput production of isolated functional polymer nanostructures on flexible substrates for the increasing application of ferroelectric polymers in flexible electronics.

  18. Fabrication of novel GMO/Eudragit E100 nanostructures for enhancing oral bioavailability of carvedilol.

    PubMed

    Patil, Sharvil S; Roy, Krishtey; Choudhary, Bhavana; Mahadik, Kakasaheb R

    2016-08-01

    In the present work, novel nanostructures comprising of glyceryl monooleate (GMO) and Eudragit E100 were prepared using high intensity ultrasonic homogenization. 3(2) Factorial design approach was used for optimization of nanostructures. Results of regression analysis revealed that the amount of GMO and Eudragit E100 had a drastic effect on particle size and percent entrapment efficiency. Optimized carvedilol-loaded nanostructures (Car-NS) were characterized by FTIR, TEM, DSC, in vitro drug release study. Pharmacokinetic parameters such as Cmax, Tmax, Ke, Ka, Vd and AUC were estimated for Car-NS upon its oral administration in Sprague-Dawley rats. Particle size of Car-NS was found to be 183 ± 2.43 nm with an entrapment efficiency of 81.4 ± 0.512%. FTIR studies revealed loading and chemical compatibility of carvedilol with the components of nanostructures. DSC thermograms did not show endothermic peak for melting of carvedilol which could be attributed to solubilization of carvedilol in molten GMO during DSC run. The prepared Car-NS released carvedilol in sustained manner over a period of 10 h as suggested by in vitro drug release study. The pharmacokinetic study of Car-NS showed significant improvement in Cmax (two fold, p < 0.001) and AUC (four folds, p < 0.001) of carvedilol when compared to carvedilol suspension. Car-NS were found to be stable for a period of 3 months. Thus, a stable, floating, multiparticulate GMO/Eudragit E100 nanostructures having ability to release the drug in sustained manner with enhanced oral bioavailability can prove to be a promising carrier system for poorly water soluble drugs. PMID:26651381

  19. Compatible solutes: ectoine and hydroxyectoine improve functional nanostructures in artificial lung surfactants.

    PubMed

    Harishchandra, Rakesh Kumar; Sachan, Amit Kumar; Kerth, Andreas; Lentzen, Georg; Neuhaus, Thorsten; Galla, Hans-Joachim

    2011-12-01

    Ectoine and hydroxyectoine belong to the family of compatible solutes and are among the most abundant osmolytes in nature. These compatible solutes protect biomolecules from extreme conditions and maintain their native function. In the present study, we have investigated the effect of ectoine and hydroxyectoine on the domain structures of artificial lung surfactant films consisting of dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylglycerol (DPPG) and the lung surfactant specific surfactant protein C (SP-C) in a molar ratio of 80:20:0.4. The pressure-area isotherms are found to be almost unchanged by both compatible solutes. The topology of the fluid domains shown by scanning force microscopy, which is thought to be responsible for the biophysical behavior under compression, however, is modified giving rise to the assumption that ectoine and hydroxyectoine are favorable for a proper lung surfactant function. This is further evidenced by the analysis of the insertion kinetics of lipid vesicles into the lipid-peptide monolayer, which is clearly enhanced in the presence of both compatible solutes. Thus, we could show that ectoine and hydroxyectoine enhance the function of lung surfactant in a simple model system, which might provide an additional rationale to inhalative therapy. PMID:21889490

  20. Nanostructural haemocompatible coatings for the internal side of artificial blood vessels

    NASA Astrophysics Data System (ADS)

    Trembecka-Wojciga, K.; Major, R.; Lackner, J. M.; Butruk-Raszeja, B.; Sanak, M.; Major, B.

    2016-03-01

    The main goal of the work was to elaborate low thrombogenicity of surface inside tube-like elements for cardiovascular system support by combination of low-temperature glow discharge and hydrogel coatings to inhibit blood-clotting cascade activation. A large share of amorphous phase silicon was observed in the microstructure analysis. The crystalline elements were uniformly distributed in the amorphous structure. Combination of low thickness, the proper microstructure and density of the coatings provided a highly flexible nature of the whole system. The blood-material interaction was analyzed in vitro in dynamic conditions by using a designed and fabricated novel blood flow simulator. Coatings deposited by the glow discharge expressed good hemocopatibile properties. The use of hydrogel coatings did not reduce coagulation parameter. Hydrogel coatings did not improve the hemocompatibility of the surface modified with carbon based coatings. Modification of surface with hydrogel resulted in further increased risk of hemolysis.

  1. A continuous roll-pulling approach for the fabrication of magnetic artificial cilia with microfluidic pumping capability.

    PubMed

    Wang, Ye; den Toonder, Jaap; Cardinaels, Ruth; Anderson, Patrick

    2016-06-21

    Magnetic artificial cilia are micro-hairs covering a surface that can be actuated using a time-dependent magnetic field to pump or mix fluids in microfluidic devices. This paper presents a novel fabrication method to realize magnetic artificial cilia using a roll-pulling process, in which a cylinder decorated with micro-pillars rolls over a liquid precursor film that contains magnetic particles at a speed up to 1 m s(-1), while a magnetic field is applied. Due to the interaction between the pillars and the liquid film, micro-hairs are pulled out of the film. In this way, surfaces with slender cone-shaped magnetic artificial cilia were produced. When integrated in a closed-loop channel, the artificial cilia were shown to be capable of generating substantial microfluidic pumping using external magnetic actuation. The spatial arrangement of the cilia can be varied by altering the layout of the micro-pillars on the roll surface. In addition, the final geometry of the individual cilia depends on the rheological properties of the precursor material in combination with the processing parameters of the roll-pulling process. A rheological study and fabrication tests were carried out for a range of precursor material compositions to obtain insight into the relation between precursor rheology and processing conditions on the one hand, and cilia geometry on the other hand. The development of this cleanroom-free, high speed and potentially large area method of production of artificial cilia is another step towards their implementation in real-life applications. PMID:27210071

  2. Fabrication and properties of ZnO nanorods within silicon nanostructures for solar cell application

    NASA Astrophysics Data System (ADS)

    Feng, Zezeng; Jia, Rui; Dou, Bingfei; Li, Haofeng; Jin, Zhi; Liu, Xinyu; Li, Feng; Zhang, Wei; Wu, Chenyang

    2015-02-01

    ZnO nanorods (NRs) were synthesized via a two-step hydrothermal method on silicon (Si) nano-textured solar cells. The optical and photovoltaic properties of silicon nanostructures coated with ZnO NRs were measured and discussed. It was found that silicon nanostructures combined with ZnO NRs can maximize the light absorption and significantly enhance the electrode contact and carrier transport ability. The series resistance was reduced from 0.98 Ω to 0.45 Ω, and short circuit current density was dramatically increased from 22.5 mA/cm2 to 27.9 mA/cm2 due to the incorporation of the ZnO NRs. The experimental results show the potential of ZnO NRs' application to the enhancement of the performance of nano-textured solar cells.

  3. Nanoimprinting by Melt Processing: An Easy Technique to Fabricate Versatile Nanostructures

    SciTech Connect

    Thomas, Jayan; Gangopadhyay, Palash; Araci, Emre; Norwood, Robert A.; Peyghambarian, Nasser

    2011-09-19

    Insights gained from rheological and contact angle measurements of plasticized and non-plasticized polymers have led to the development of a simple method to print densely packed micro- and nanoscale features without proximity effects. Versatile large-area nanopatterns and landscapes with a high degree of fidelity are successfully imprinted. This technique promises a variety of polymer nanostructures to a wide spectrum of scientific fields.

  4. Fabrication of hybrid nanostructured arrays using a PDMS/PDMS replication process.

    PubMed

    Hassanin, H; Mohammadkhani, A; Jiang, K

    2012-10-21

    In the study, a novel and low cost nanofabrication process is proposed for producing hybrid polydimethylsiloxane (PDMS) nanostructured arrays. The proposed process involves monolayer self-assembly of polystyrene (PS) spheres, PDMS nanoreplication, thin film coating, and PDMS to PDMS (PDMS/PDMS) replication. A self-assembled monolayer of PS spheres is used as the first template. Second, a PDMS template is achieved by replica moulding. Third, the PDMS template is coated with a platinum or gold layer. Finally, a PDMS nanostructured array is developed by casting PDMS slurry on top of the coated PDMS. The cured PDMS is peeled off and used as a replica surface. In this study, the influences of the coating on the PDMS topography, contact angle of the PDMS slurry and the peeling off ability are discussed in detail. From experimental evaluation, a thickness of at least 20 nm gold layer or 40 nm platinum layer on the surface of the PDMS template improves the contact angle and eases peeling off. The coated PDMS surface is successfully used as a template to achieve the replica with a uniform array via PDMS/PDMS replication process. Both the PDMS template and the replica are free of defects and also undistorted after demoulding with a highly ordered hexagonal arrangement. In addition, the geometry of the nanostructured PDMS can be controlled by changing the thickness of the deposited layer. The simplicity and the controllability of the process show great promise as a robust nanoreplication method for functional applications. PMID:22868401

  5. Tunable top-down fabrication and functional surface coating of single-crystal titanium dioxide nanostructures and nanoparticles

    NASA Astrophysics Data System (ADS)

    Ha, Seungkyu; Janissen, Richard; Ussembayev, Yera Ye.; van Oene, Maarten M.; Solano, Belen; Dekker, Nynke H.

    2016-05-01

    Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile TiO2 nanocylinders tethered with individual DNA molecules for use as force- and torque-transducers in an optical torque wrench. These developments provide the means for increased exploitation of the superior material properties of single-crystal TiO2 at the nanoscale.Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization. Here, we introduce a novel top-down approach that allows for batch fabrication of uniform high-aspect-ratio single-crystal TiO2 nanostructures with targeted sidewall profiles. We complement our fabrication approach with a functionalization strategy that achieves dense, uniform, and area-selective coating with a variety of biomolecules. This allows us to fabricate single-crystal rutile

  6. Fabrication of Graphene-isolated-Au-nanocrystal Nanostructures for Multimodal Cell Imaging and Photothermal-enhanced Chemotherapy

    PubMed Central

    Bian, Xia; Song, Zhi-Ling; Qian, Yu; Gao, Wei; Cheng, Zhen-Qian; Chen, Long; Liang, Hao; Ding, Ding; Nie, Xiang-Kun; Chen, Zhuo; Tan, Weihong

    2014-01-01

    Using nanomaterials to develop multimodal systems has generated cutting-edge biomedical functions. Herein, we develop a simple chemical-vapor-deposition method to fabricate graphene-isolated-Au-nanocrystal (GIAN) nanostructures. A thin layer of graphene is precisely deposited on the surfaces of gold nanocrystals to enable unique capabilities. First, as surface-enhanced-Raman-scattering substrates, GIANs quench background fluorescence and reduce photocarbonization or photobleaching of analytes. Second, GIANs can be used for multimodal cell imaging by both Raman scattering and near-infrared (NIR) two-photon luminescence. Third, GIANs provide a platform for loading anticancer drugs such as doxorubicin (DOX) for therapy. Finally, their NIR absorption properties give GIANs photothermal therapeutic capability in combination with chemotherapy. Controlled release of DOX molecules from GIANs is achieved through NIR heating, significantly reducing the possibility of side effects in chemotherapy. The GIANs have high surface areas and stable thin shells, as well as unique optical and photothermal properties, making them promising nanostructures for biomedical applications. PMID:25178354

  7. Fabrication of Graphene-isolated-Au-nanocrystal Nanostructures for Multimodal Cell Imaging and Photothermal-enhanced Chemotherapy

    NASA Astrophysics Data System (ADS)

    Bian, Xia; Song, Zhi-Ling; Qian, Yu; Gao, Wei; Cheng, Zhen-Qian; Chen, Long; Liang, Hao; Ding, Ding; Nie, Xiang-Kun; Chen, Zhuo; Tan, Weihong

    2014-09-01

    Using nanomaterials to develop multimodal systems has generated cutting-edge biomedical functions. Herein, we develop a simple chemical-vapor-deposition method to fabricate graphene-isolated-Au-nanocrystal (GIAN) nanostructures. A thin layer of graphene is precisely deposited on the surfaces of gold nanocrystals to enable unique capabilities. First, as surface-enhanced-Raman-scattering substrates, GIANs quench background fluorescence and reduce photocarbonization or photobleaching of analytes. Second, GIANs can be used for multimodal cell imaging by both Raman scattering and near-infrared (NIR) two-photon luminescence. Third, GIANs provide a platform for loading anticancer drugs such as doxorubicin (DOX) for therapy. Finally, their NIR absorption properties give GIANs photothermal therapeutic capability in combination with chemotherapy. Controlled release of DOX molecules from GIANs is achieved through NIR heating, significantly reducing the possibility of side effects in chemotherapy. The GIANs have high surface areas and stable thin shells, as well as unique optical and photothermal properties, making them promising nanostructures for biomedical applications.

  8. Fabrication of graphene-isolated-Au-nanocrystal nanostructures for multimodal cell imaging and photothermal-enhanced chemotherapy.

    PubMed

    Bian, Xia; Song, Zhi-Ling; Qian, Yu; Gao, Wei; Cheng, Zhen-Qian; Chen, Long; Liang, Hao; Ding, Ding; Nie, Xiang-Kun; Chen, Zhuo; Tan, Weihong

    2014-01-01

    Using nanomaterials to develop multimodal systems has generated cutting-edge biomedical functions. Herein, we develop a simple chemical-vapor-deposition method to fabricate graphene-isolated-Au-nanocrystal (GIAN) nanostructures. A thin layer of graphene is precisely deposited on the surfaces of gold nanocrystals to enable unique capabilities. First, as surface-enhanced-Raman-scattering substrates, GIANs quench background fluorescence and reduce photocarbonization or photobleaching of analytes. Second, GIANs can be used for multimodal cell imaging by both Raman scattering and near-infrared (NIR) two-photon luminescence. Third, GIANs provide a platform for loading anticancer drugs such as doxorubicin (DOX) for therapy. Finally, their NIR absorption properties give GIANs photothermal therapeutic capability in combination with chemotherapy. Controlled release of DOX molecules from GIANs is achieved through NIR heating, significantly reducing the possibility of side effects in chemotherapy. The GIANs have high surface areas and stable thin shells, as well as unique optical and photothermal properties, making them promising nanostructures for biomedical applications. PMID:25178354

  9. Fabrication and Spark plasma sintering of nanostructured bismuth telluride (Bi{sub 2}Te{sub 3})

    SciTech Connect

    Saleemi, Mohsin; Toprak, Muhammet S.; Li, Shanghua; Johnsson, Mats; Muhammed, Mamoun

    2012-06-26

    Thermoelectric (TE) devices can harvest residual low-grade waste heat energy. Bismuth telluride (Bi{sub 2}Te{sub 3}) and its alloys are mostly used TE materials in the bulk form for making TE modules. We report a simple, fast and very high yield synthetic process for the bulk Bi{sub 2}Te{sub 3} nanopowders with hexagonal plate like morphology. Spark plasma sintering (SPS) process has been optimized in order to preserve nanostructure while achieving a high compaction density of the pellets. Electron microscopy analysis was used to determine the effect of SPS parameters during compaction on the grain growth. Optimal conditions for the fabricated nanopowder was determined as 673 K, 70 MPa pressure with no holding time, which resulted in average lateral grain size in the range of 165-190 nm for a compact density of 98%. About 50% reduction of thermal conductivity was observed as compared to its bulk counterparts, revealing the feasibility of suggested route in the preservation of nanostructure and enhanced phonon scattering.

  10. Fabrication of highly oriented microstructures and nanostructures of ferroelectric P(VDF-TrFE) copolymer via dip-pen nanolithography

    NASA Astrophysics Data System (ADS)

    Tang, Qian; Shi, San-qiang; Huang, Haitao; Zhou, Li Min

    2004-07-01

    Microstructures and nanostructures of ferroelectric copolymer poly(vinylidene fluoride-trifluorethylene) [P(VDF-TrFE)] are fabricated on gold via dip-pen nanolithography (DPN). The thickness of the patterns is about 1 nm after a critical concentration, regardless of the pattern scale. The polymer molecules are well orientated according to an all- trans conformation and have ferroelectric properties on the gold surface through electrostatic interaction, rather than the formation of chemical bonds. Increasing temperature has a positive effect on the growth rate of the P(VDF-TrFE). The electrostatic interaction between the P(VDF-TrFE) and the gold substrate and the intramolecular interaction of polymer molecules play important roles in the growth rate of the P(VDF-TrFE) patterns.

  11. Fabrication of Hierarchically Micro- and Nano-structured Mold Surfaces Using Laser Ablation for Mass Production of Superhydrophobic Surfaces

    NASA Astrophysics Data System (ADS)

    Noh, Jiwhan; Lee, Jae-Hoon; Na, Suckjoo; Lim, Hyuneui; Jung, Dae-Hwan

    2010-10-01

    Many studies have examined the formation of surfaces with mixed patterns of micro- and nano-sized lotus leaves that have hydrophobic properties. In this study, micro- and nano-shapes such as lotus leaves were fabricated on a metal mold surface using laser ablation and ripple formation. A microstructure on the mold surface was replicated onto poly(dimethylsiloxane) (PDMS) using the polymer casting method to manufacture low-cost hydrophobic surfaces. A PDMS surface with micro- and nano-structures that were the inverse image of a lotus leaf showed hydrophobic characteristics (water contact angle: 157°). From these results, we deduced that portions of the microstructures were wet and that air gaps existed between the microstructures and the water drops. In this paper we suggest the possibility of the mass production of hydrophobic plastic surfaces and the development of a methodology for the hydrophobic texturing of various polymer surfaces, using the polymer casting method with laser-processed molds.

  12. Fabrication of Complex Three-Dimensional Nanostructures from Self-Assembling Block Copolymer Materials on Patterned Surfaces: A computational Study

    NASA Astrophysics Data System (ADS)

    Ye, Xianggui; Edwards, Brian J.; Khomami, Bamin

    2010-03-01

    Chemically patterned substrates can direct the assembly of adsorbed layers or thin films of block copolymers. Here, we consider the self-assembly of a lamella-forming diblock copolymer on periodically stripe-patterned substrates. The morphology of the block copolymer follows the pattern at the substrate; however, with an increasing degree of mismatch between the width of the stripe-pattern and the periodic spacing of bulk block copolymer, novel morphologies have been found. Therefore, it is possible to adjust the morphologies in thin bock copolymer films by adjusting the mismatch between the width of the stripe-pattern and the periodic spacing of the bulk block copolymer. These results demonstrate a promising strategy for fabrication of complex interfacial nanostructures from chemically patterned templates.

  13. Engineering artificial machines from designable DNA materials for biomedical applications.

    PubMed

    Qi, Hao; Huang, Guoyou; Han, Yulong; Zhang, Xiaohui; Li, Yuhui; Pingguan-Murphy, Belinda; Lu, Tian Jian; Xu, Feng; Wang, Lin

    2015-06-01

    Deoxyribonucleic acid (DNA) emerges as building bricks for the fabrication of nanostructure with complete artificial architecture and geometry. The amazing ability of DNA in building two- and three-dimensional structures raises the possibility of developing smart nanomachines with versatile controllability for various applications. Here, we overviewed the recent progresses in engineering DNA machines for specific bioengineering and biomedical applications. PMID:25547514

  14. Engineering Artificial Machines from Designable DNA Materials for Biomedical Applications

    PubMed Central

    Huang, Guoyou; Han, Yulong; Zhang, Xiaohui; Li, Yuhui; Pingguan-Murphy, Belinda; Lu, Tian Jian; Xu, Feng

    2015-01-01

    Deoxyribonucleic acid (DNA) emerges as building bricks for the fabrication of nanostructure with complete artificial architecture and geometry. The amazing ability of DNA in building two- and three-dimensional structures raises the possibility of developing smart nanomachines with versatile controllability for various applications. Here, we overviewed the recent progresses in engineering DNA machines for specific bioengineering and biomedical applications. PMID:25547514

  15. Design and Fabrication of Ultrathin Plasmonic Nanostructures for Photovoltaics, Color Filtering and Biosensing

    NASA Astrophysics Data System (ADS)

    Zeng, Beibei

    Since the first report of the extraordinary optical transmission (EOT) phenomenon through periodic subwavelength hole arrays milled in optically-thick metal film, plasmonics have generated considerable interest because they enable new fundamental science and application technologies. Central to this phenomenon is the role of surface plasmon polaritons (SPPs), which are essentially electromagnetic waves trapped at the interface between a metal and a dielectric medium through their interactions with free electrons at the metal surface. The resonant interaction between the incident light and surface charge oscillations enables the concentration and manipulation of light at deep subwavelength scales, opening up exciting application opportunities ranging from subwavelength optics and optoelectronics to bio/chemical sensing. Furthermore, additional phenomena arise as the thickness of metal film decreases to be comparable to its skin depth (optically-thin), and the single-interface SPPs on the top and bottom metal surfaces combine to form two coupled SPPs, the long-range and short-range SPPs. Until now, much less work has focused on the study of surface plasmon resonances (SPRs) in ultrathin nanostructured metals. This dissertation seeks to elucidate underlying physical mechanisms of SPRs in ultrathin nanostructured metals and tailor them for practical applications. Inspired by state-of-the-art advances on plasmonics in optically-thick nanostructured metals, one- (1D) and two-dimensional (2D) ultrathin plasmonic nanostructures are exploited for particular applications in three essential areas: photovoltaics, color filters and biosensors, achieving superior performances compared with their optically-thick counterparts. More specifically, this thesis is focused on systematic investigations on: (1) plasmonic transparent electrodes for organic photovoltaics and polarization-insensitive optical absorption enhancement in the active layer; (2) plasmonic subtractive color filters

  16. Fabrication of ZnO nanostructures sensitized with CdS quantum dots for photovoltaic application using a convenient solution method

    SciTech Connect

    Liu, Huan; Zhang, Gengmin; Yin, Jianbo; Liang, Jia; Sun, Wentao; Shen, Ziyong

    2015-01-15

    Zinc oxide (ZnO) nanostructures sensitized with cadmium sulfide quantum dots (CdS QDs) were fabricated using a simple and inexpensive solution method. ZnO nanostructures, in the form of either nanocones or nanorods, were first grown directly from fluorine-doped tin oxide (FTO) substrates in aqueous solutions of zinc nitrate (Zn(NO{sub 3}){sub 2}) and hexamethylenetetramine (HMTA, C{sub 6}H{sub 12}N{sub 4}) under external voltages. Then, CdS QDs were attached to these ZnO nanostructures via reactions in the mixed aqueous solutions of cadmium nitrate (Cd(NO{sub 3}){sub 2}) and thioacetamide (C{sub 2}H{sub 5}NS). Photovoltaic responses were obtained from the quantum dot sensitized solar cells (QDSSCs) in which these CdS QD-covered ZnO nanostructures were employed as the photoanodes. The morphologies of the ZnO nanostructures, which could be effectively modulated via the substrate location in the solutions during the fabrication, were found to have played an important role in determining the properties of the QDSSCs.

  17. TOPICAL REVIEW: Fabrication of micro- and nano-structured materials using mask-less processes

    NASA Astrophysics Data System (ADS)

    Roy, Sudipta

    2007-11-01

    Micro- and nano-scale devices are used in electronics, micro-electro- mechanical, bio-analytical and medical components. An essential step for the fabrication of such small scale devices is photolithography. Photolithography requires a master mask to transfer micrometre or sub-micrometre scale patterns onto a substrate. The requirement of a physical, rigid mask can impede progress in applications which require rapid prototyping, flexible substrates, multiple alignment and 3D fabrication. Alternative technologies, which do not require the use of a physical mask, are suitable for these applications. In this paper mask-less methods of micro- and nano-scale fabrication have been discussed. The most common technique, which is the laser direct imaging (LDI), technique has been applied to fabricate micrometre scale structures on printed circuit boards, glass and epoxy. LDI can be combined with chemical methods to deposit metals, inorganic materials as well as some organic entities at the micrometre scale. Inkjet technology can be used to fabricate micrometre patterns of etch resists, organic transistors as well as arrays for bioanalysis. Electrohydrodynamic atomisation is used to fabricate micrometre scale ceramic features. Electrochemical methodologies offer a variety of technical solutions for micro- and nano-fabrication owing to the fact that electron charge transfer can be constrained to a solid liquid interface. Electrochemical printing is an adaptation of inkjet printing which can be used for rapid prototyping of metallic circuits. Micro-machining using nano-second voltage pulses have been used to fabricate high precision features on metals and semiconductors. Optimisation of reactor, electrochemistry and fluid flow (EnFACE) has also been employed to transfer micrometre scale patterns on a copper substrate. Nano-scale features have been fabricated by using specialised tools such as scanning tunnelling microscopy, atomic force microscopy and focused ion beam. The

  18. Novel Nanostructures of Rutile Fabricated by Templating against Yarns of Polystyrene Nanofibrils and Their Catalytic Applications

    PubMed Central

    Lu, Ping; Xia, Younan

    2013-01-01

    This article describes a facile approach to the synthesis of rutile nanostructures in the form of porous fibers or bundles of nanotubes by maneuvering the surface wettability of yarns made of polystyrene nanofibrils. Specifically, hierarchically porous fibers were obtained by hydrolyzing titanium tetraisopropoxide to form TiO2 nanoparticles in the void spaces among hydrophobic nanofibrils in each yarn. After calcination in air at 800 °C, the resultant fibers were comprised of many interconnected rutile nanoparticles whose diameters were in the range of 20–80 nm. After converting the nanofibrils and yarns into hydrophilic surfaces through plasma treatment, however, the TiO2 formed conformal coatings on the surfaces of nanofibrils in each yarn during hydrolysis instead of just filling the void spaces among the nanofibrils. As a result, bundles of rutile nanotubes were obtained after the sample had been calcined in air at 800 °C. The thermodynamically stable rutile nanostructures were then explored as supports for Pt nanoparticles whose catalytic activity was evaluated using the reduction of p-nitrophenol by NaBH4. The Pt supported on porous rutile fibers exhibited a better performance than the Pt on rutile nanotubes in terms of both induction time (tind) and apparent rate constant (kapp). PMID:23763369

  19. MBE fabrication of self-assembled Si and metal nanostructures on Si surfaces

    SciTech Connect

    Galiana, Natalia; Martin, Pedro-Pablo; Munuera, Carmen; Varela del Arco, Maria; Soria, Federico; Ocal, Carmen; Ruiz, Ana; Alonso, Maria

    2006-01-01

    Two types of fairly regular distributions of Si nanostructures, of interest as templates to grow spatially controlled ensembles of metal (Co, Fe, Ag, etc.) nanostructures, are presented in this paper. Both of them are achieved by self-assembling processes during Si homoepitaxy. One corresponds to films grown by molecular beam epitaxy (MBE) on Si(0 0 1)-2 x 1 surfaces with low (<1 degree) miscut angles. In this case, arrays of 3D Si-islands displaying well defined pyramid-like shapes can be obtained, as evidenced by Scanning Force Microscopy (SFM) and Scanning Transmission Electron Microscopy (STEM). Such arrays exhibit strong similarities with those reported for Ge and SiGe islands on Si(0 0 1), and may thus serve as a simpler route to produce ordered distributions of metallic nanodots. On the other hand, on Si(1 1 1)-7 x 7 vicinal substrates misoriented 4 degrees toward the View the MathML source direction, step rearrangement during homoepitaxy permits to produce nanopatterned surfaces, the building-blocks of which are triangular (1 1 1) platforms, with lateral dimensions of hundreds of nanometers, bound by step bunches about 30 nm high. Furthermore, different Ag deposition experiments support this spontaneous patterning on Si(1 1 1) as a promising approach to achieve regular distributions of metallic nanocrystals with an overall homogeneity in sizes, shapes and spacing.

  20. Fabrication of nano-structured TiO2 coatings using a microblast deposition technique

    NASA Astrophysics Data System (ADS)

    McDonnell, Kevin A.; English, Niall J.; Stallard, Charlie P.; Rahman, Mahfujur; Dowling, Denis P.

    2013-06-01

    Micron thick titanium dioxide (TiO2) coatings exhibiting a nano-structured, anatase, meso-porous structure were successfully deposited across a range of polymer, conductive glass and metallic substrates at low velocities using a microblasting technique. This process was conducted at atmospheric pressure using compressed air as the carrier gas and commercially available agglomerated nano particles of TiO2 as the feedstock. An examination of the effect of impact kinetics on the agglomerated powder before and after deposition was undertaken. A further examination of the coating microstructure along with photocurrent density measurements before and after thermal treatments was explored. Owing to the low temperature and velocity of the powder during deposition no change in phase of the powder or damage to the substrate was observed. The resulting TiO2 coatings exhibited relatively good adhesion on both titanium and FTO coated glass substrates with coating thickness of approximately 1.5 μm. Photo-catalytic performance was measured under solar simulator illumination using a photo-electrochemical cell (PEC) with a 5-fold increase in performance observed after thermal treatment of the TiO2 coated substrates. Microblasting was demonstrated to be a rapid and cost effective method for the deposition of nano-structured, photo-catalytic, anatase TiO2 coatings.

  1. MBE fabrication of self-assembled Si and metal nanostructures on Si surfaces

    NASA Astrophysics Data System (ADS)

    Galiana, Natalia; Martin, Pedro-Pablo; Munuera, Carmen; Varela, María; Soria, Federico; Ocal, Carmen; Ruiz, Ana; Alonso, María

    2006-09-01

    Two types of fairly regular distributions of Si nanostructures, of interest as templates to grow spatially controlled ensembles of metal (Co, Fe, Ag, etc.) nanostructures, are presented in this paper. Both of them are achieved by self-assembling processes during Si homoepitaxy. One corresponds to films grown by molecular beam epitaxy (MBE) on Si(0 0 1)-2 × 1 surfaces with low (<1°) miscut angles. In this case, arrays of 3D Si-islands displaying well defined pyramid-like shapes can be obtained, as evidenced by Scanning Force Microscopy (SFM) and Scanning Transmission Electron Microscopy (STEM). Such arrays exhibit strong similarities with those reported for Ge and SiGe islands on Si(0 0 1), and may thus serve as a simpler route to produce ordered distributions of metallic nanodots. On the other hand, on Si(1 1 1)-7 × 7 vicinal substrates misoriented 4° toward the [1 1 2¯] direction, step rearrangement during homoepitaxy permits to produce nanopatterned surfaces, the building-blocks of which are triangular (1 1 1) platforms, with lateral dimensions of hundreds of nanometers, bound by step bunches about 30 nm high. Furthermore, different Ag deposition experiments support this spontaneous patterning on Si(1 1 1) as a promising approach to achieve regular distributions of metallic nanocrystals with an overall homogeneity in sizes, shapes and spacing.

  2. Biomimetic gyroid nanostructures exceeding their natural origins

    PubMed Central

    Gan, Zongsong; Turner, Mark D.; Gu, Min

    2016-01-01

    Using optical two-beam lithography with improved resolution and enhanced mechanical strength, we demonstrate the replication of gyroid photonic nanostructures found in the butterfly Callophrys rubi. These artificial structures are shown to have size, controllability, and uniformity that are superior to those of their biological counterparts. In particular, the elastic Young’s modulus of fabricated nanowires is enhanced by up to 20%. As such, the circular dichroism enabled by the gyroid nanostructures can operate in the near-ultraviolet wavelength region, shorter than that supported by the natural butterfly wings of C. rubi. This fabrication technique provides a unique tool for extracting three-dimensional photonic designs from nature and will aid the investigation of biomimetic nanostructures. PMID:27386542

  3. Biomimetic gyroid nanostructures exceeding their natural origins.

    PubMed

    Gan, Zongsong; Turner, Mark D; Gu, Min

    2016-05-01

    Using optical two-beam lithography with improved resolution and enhanced mechanical strength, we demonstrate the replication of gyroid photonic nanostructures found in the butterfly Callophrys rubi. These artificial structures are shown to have size, controllability, and uniformity that are superior to those of their biological counterparts. In particular, the elastic Young's modulus of fabricated nanowires is enhanced by up to 20%. As such, the circular dichroism enabled by the gyroid nanostructures can operate in the near-ultraviolet wavelength region, shorter than that supported by the natural butterfly wings of C. rubi. This fabrication technique provides a unique tool for extracting three-dimensional photonic designs from nature and will aid the investigation of biomimetic nanostructures. PMID:27386542

  4. Fabrication of poly(ethylene glycol): gelatin methacrylate composite nanostructures with tunable stiffness and degradation for vascular tissue engineering.

    PubMed

    Kim, Peter; Yuan, Alex; Nam, Ki-Hwan; Jiao, Alex; Kim, Deok-Ho

    2014-06-01

    Although synthetic polymers are desirable in tissue engineering applications for the reproducibility and tunability of their properties, synthetic small diameter vascular grafts lack the capability to endothelialize in vivo. Thus, synthetically fabricated biodegradable tissue scaffolds that reproduce important aspects of the extracellular environment are required to meet the urgent need for improved vascular grafting materials. In this study, we have successfully fabricated well-defined nanopatterned cell culture substrates made of a biodegradable composite hydrogel consisting of poly(ethylene glycol) dimethacrylate (PEGDMA) and gelatin methacrylate (GelMA) by using UV-assisted capillary force lithography. The elasticity and degradation rate of the composite PEG-GelMA nanostructures were tuned by varying the ratios of PEGDMA and GelMA. Human umbilical vein endothelial cells (HUVECs) cultured on nanopatterned PEG-GelMA substrates exhibited enhanced cell attachment compared with those cultured on unpatterned PEG-GelMA substrates. Additionally, HUVECs cultured on nanopatterned PEG-GelM substrates displayed well-aligned, elongated morphology similar to that of native vascular endothelial cells and demonstrated rapid and directionally persistent migration. The ability to alter both substrate stiffness and degradation rate and culture endothelial cells with increased elongation and alignment is a promising next step in recapitulating the properties of native human vascular tissue for tissue engineering applications. PMID:24717683

  5. ZnO-based ultra-violet light emitting diodes and nanostructures fabricated by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Chen, Miin-Jang; Yang, Jer-Ren; Shiojiri, Makoto

    2012-07-01

    We have investigated ZnO-based light-emitting diodes (LEDs) fabricated by atomic layer deposition (ALD), demonstrating that ALD is one of the noteworthy techniques to prepare high-quality ZnO required for ultraviolet (UV) photonic devices. Here, we review our recent investigations on different ZnO-based heterojunction LEDs such as n-ZnO/p-GaN LEDS, n-ZnO:Al/ZnO nanodots-SiO2 composite/p-GaN LEDS, n-ZnO/ZnO nanodots-SiO2 composite/p-AlGaN LEDs, n-ZnO:Al/i-ZnO/p-SiC(4H) LEDs, and also on ZnO-based nanostructures including ZnO quantum dots embedded in SiO2 nanoparticle layer, ZnO nanopillars on sapphire substrates, Al-doped ZnO films on sapphire substrate and highly (0 0 0 1)-oriented ZnO films on amorphous glass substrate. The latest investigation also demonstrated p-type ZnO:P films prepared on amorphous silica substrates, which allow us to fabricate ZnO-based homojunction LEDs. These devices and structures were studied by x-ray diffraction and various analytical electron microscopy observations as well as electric and electro-optical measurements.

  6. Facile fabrication of nano-structured silica hybrid film with superhydrophobicity by one-step VAFS approach

    NASA Astrophysics Data System (ADS)

    Jia, Yi; Yue, Renliang; Liu, Gang; Yang, Jie; Ni, Yong; Wu, Xiaofeng; Chen, Yunfa

    2013-01-01

    Here we report a novel one-step vapor-fed aerosol flame synthesis (VAFS) method to attain silica hybrid film with superhydrophobicity on normal glass and other engineering material substrates using hexamethyldisiloxane (HMDSO) as precursor. The deposited nano-structured silica films represent excellent superhydrophobicity with contact angle larger than 150° and sliding angle below 5°, without any surface modification or other post treatments. SEM photographs proved that flame-made SiO2 nanoparticles formed dual-scale surface roughness on the substrates. It was confirmed by FTIR and XPS that the in situ formed organic fragments on the particle surface as species like (CH3)xSiO2-x/2 (x = 1, 2, 3) which progressively lowered the surface energy of fabricated films. Thus, these combined dual-scale roughness and lowered surface energy cooperatively produced superhydrophobic films. IR camera had been used to monitor the real-time flame temperature. It is found that the inert dilution gas inflow played a critical role in attaining superhydrophobicity due to its cooling and anti-oxidation effect. This method is facile and scalable for diverse substrates, without any requirement of complex equipments and multiple processing steps. It may contribute to the industrial fabrication of superhydrophobic films.

  7. Unstrained and strained semiconductor nanostructure fabrication via molecular beam epitaxical growth on non-planar patterned gallium arsenide(001) substrates

    NASA Astrophysics Data System (ADS)

    Konkar, Atul Ashok

    1999-11-01

    This dissertation contributes to three areas in the emerging field of nanostructures: (i) fabrication of quantum wires (QWR) and quantum dots (QD) via molecular beam epitaxy (MBE) on non-planar patterned substrates (NPPS), (ii) nature of mesa profile evolution with MBE growth, and (iii) nature of highly strained epitaxy on nanoscale mesas. Using the approach of substrate-encoded size-reducing epitaxy (SESRE) we have successfully fabricated QWRs and QBs in the unstrained GaAs/AlGaAs system and QBs in the highly strained InAs/GaAs system on GaAs (001) mesas with edges oriented along the <100> directions. By controlling the InAs delivery just below that required for 3D island formation on planar GaAs (001) substrates and optimizing the growth conditions, we have been able to selectively position 3D InAs islands on stripe mesas with appropriate shape, size, and orientation. Studies of the effect of growth interruption on the mesa growth profile evolution reveal the dynamic nature of the NPPS surface at typical MBE growth conditions. In the case of [100] oriented stripe mesas, during growth adatom migration was seen from the {101}, sidewalls to the (001) mesa top, whereas during growth interruption adatom migration from the mesa top to the sidewalls was observed. These results have significant implications for the relative magnitudes of the energy barriers relevant to the crystal growth processes on different surfaces. Studies of growth profile evolution dependence on the orientation and the sidewall profile of mesas created via focused ion beam assisted chemical etching evidenced the mesa profiles suitable for nanostructure fabrication via SESRE. We observe a dramatic suppression of 3D island formation during InAs deposition on nanoscale square mesas due to the strain relief available at the free edges of the mesa and substantial strain accommodation in the underlying mesa. The interplay between the strain build-up and the interfacet migration kinetics causes reversal

  8. Self-assembled nanostructured resistive switching memory devices fabricated by templated bottom-up growth.

    PubMed

    Song, Ji-Min; Lee, Jang-Sik

    2016-01-01

    Metal-oxide-based resistive switching memory device has been studied intensively due to its potential to satisfy the requirements of next-generation memory devices. Active research has been done on the materials and device structures of resistive switching memory devices that meet the requirements of high density, fast switching speed, and reliable data storage. In this study, resistive switching memory devices were fabricated with nano-template-assisted bottom up growth. The electrochemical deposition was adopted to achieve the bottom-up growth of nickel nanodot electrodes. Nickel oxide layer was formed by oxygen plasma treatment of nickel nanodots at low temperature. The structures of fabricated nanoscale memory devices were analyzed with scanning electron microscope and atomic force microscope (AFM). The electrical characteristics of the devices were directly measured using conductive AFM. This work demonstrates the fabrication of resistive switching memory devices using self-assembled nanoscale masks and nanomateirals growth from bottom-up electrochemical deposition. PMID:26739122

  9. Self-assembled nanostructured resistive switching memory devices fabricated by templated bottom-up growth

    PubMed Central

    Song, Ji-Min; Lee, Jang-Sik

    2016-01-01

    Metal-oxide-based resistive switching memory device has been studied intensively due to its potential to satisfy the requirements of next-generation memory devices. Active research has been done on the materials and device structures of resistive switching memory devices that meet the requirements of high density, fast switching speed, and reliable data storage. In this study, resistive switching memory devices were fabricated with nano-template-assisted bottom up growth. The electrochemical deposition was adopted to achieve the bottom-up growth of nickel nanodot electrodes. Nickel oxide layer was formed by oxygen plasma treatment of nickel nanodots at low temperature. The structures of fabricated nanoscale memory devices were analyzed with scanning electron microscope and atomic force microscope (AFM). The electrical characteristics of the devices were directly measured using conductive AFM. This work demonstrates the fabrication of resistive switching memory devices using self-assembled nanoscale masks and nanomateirals growth from bottom-up electrochemical deposition. PMID:26739122

  10. Strength Improvement of Glass Substrates by Using Surface Nanostructures

    NASA Astrophysics Data System (ADS)

    Kumar, Amarendra; Kashyap, Kunal; Hou, Max T.; Yeh, J. Andrew

    2016-05-01

    Defects and heterogeneities degrade the strength of glass with different surface and subsurface properties. This study uses surface nanostructures to improve the bending strength of glass and investigates the effect of defects on three glass types. Borosilicate and aluminosilicate glasses with a higher defect density than fused silica exhibited 118 and 48 % improvement, respectively, in bending strength after surface nanostructure fabrication. Fused silica, exhibited limited strength improvement. Therefore, a 4-μm-deep square notch was fabricated to study the effect of a dominant defect in low defect density glass. The reduced bending strength of fused silica caused by artificial defect increased 65 % in the presence of 2-μm-deep nanostructures, and the fused silica regained its original strength when the nanostructures were 4 μm deep. In fragmentation tests, the fused silica specimen broke into two major portions because of the creation of artificial defects. The number of fragments increased when nanostructures were fabricated on the fused silica surface. Bending strength improvement and fragmentation test confirm the usability of this method for glasses with low defect densities when a dominant defect is present on the surface. Our findings indicate that nanostructure-based strengthening is suitable for all types of glasses irrespective of defect density, and the observed Weibull modulus enhancement confirms the reliability of this method.

  11. Strength Improvement of Glass Substrates by Using Surface Nanostructures.

    PubMed

    Kumar, Amarendra; Kashyap, Kunal; Hou, Max T; Yeh, J Andrew

    2016-12-01

    Defects and heterogeneities degrade the strength of glass with different surface and subsurface properties. This study uses surface nanostructures to improve the bending strength of glass and investigates the effect of defects on three glass types. Borosilicate and aluminosilicate glasses with a higher defect density than fused silica exhibited 118 and 48 % improvement, respectively, in bending strength after surface nanostructure fabrication. Fused silica, exhibited limited strength improvement. Therefore, a 4-μm-deep square notch was fabricated to study the effect of a dominant defect in low defect density glass. The reduced bending strength of fused silica caused by artificial defect increased 65 % in the presence of 2-μm-deep nanostructures, and the fused silica regained its original strength when the nanostructures were 4 μm deep. In fragmentation tests, the fused silica specimen broke into two major portions because of the creation of artificial defects. The number of fragments increased when nanostructures were fabricated on the fused silica surface. Bending strength improvement and fragmentation test confirm the usability of this method for glasses with low defect densities when a dominant defect is present on the surface. Our findings indicate that nanostructure-based strengthening is suitable for all types of glasses irrespective of defect density, and the observed Weibull modulus enhancement confirms the reliability of this method. PMID:27194443

  12. A novel technology for fabricating customizable VLSI artificial neural network chips

    SciTech Connect

    Fu, C.Y.; Law, B.; Chapline, G.; Swenson, D.

    1992-02-05

    This paper describes an implementation of hardware neural networks using highly linear thin-film resistor technology and an 8-bit binary weight circuit to produce customizable artificial neural network chips and systems. These neural networks are programmed using precision laser cutting and deposition. The fast turnaround of laser-based customization allows us to explore different neural network architectures and to rapidly program the synaptic weights. Our customizable chip allows us to expand an artificial network laterally and vertically. This flexibility permits us to build very large neural network systems.

  13. The fabrication of silicon nanostructures by focused-ion-beam implantation and TMAH wet etching.

    PubMed

    Sievilä, Päivi; Chekurov, Nikolai; Tittonen, Ilkka

    2010-04-01

    Local gallium implantation of silicon by a focused ion beam (FIB) has been used to create a mask for anisotropic tetramethylammonium hydroxide (TMAH) wet etching. The dependence of the etch stop properties of gallium-doped silicon on the implanted dose has been investigated and a dose of 4 x 10(13) ions cm(- 2) has been determined to be the threshold value for achieving observable etching resistance. Only a thin, approx. 50 nm, surface layer is found to be durable enough to serve as a mask with a high selectivity of at least 2000:1 between implanted and non-implanted areas. The combined FIB-TMAH process has been used to generate various types of 3D nanostructures including nanochannels separated by thin vertical sidewalls with aspect ratios up to 1:30, ultra-narrow (approx. 25 nm) freestanding bridges and cantilevers, and gratings with a resolution of 20 lines microm(- 1). PMID:20215652

  14. Properties and fabrication of nanostructured 2Cr-Al₂O₃ composite for prosthetic bearing replacements.

    PubMed

    Park, Na-Ra; Shon, In-Jin

    2014-12-01

    Cr2O3 and Al powder were used as raw powders, and were milled by the high energy ball milling method. The nanostructured 2Cr-Al2O3 composite from the milled powder was both synthesized and densificated within a short time, by the pulsed current activated sintering (PCAS) apparatus. The relative density of the sintered 2Cr-Al2O3 composite was 99%. The hardness and the fracture toughness of the specimen were 1630 kg/mm(2), and 9.3 MPa·m(1/2), respectively. The weight loss of the composite was measured by a pin-on-disk type apparatus, without a lubricant. Lastly, the 2Cr-Al2O3 composite has a very good cell viability. PMID:25491856

  15. Fabrication of ZnO photonic amorphous diamond nanostructure from parrot feathers for modulated photoluminescence properties

    NASA Astrophysics Data System (ADS)

    Zhang, Zhengli; Yu, Ke; Liao, Na; Yin, Haihong; Lou, Lei; Yu, Qian; Liao, Yuanyuan; Zhu, Ziqiang

    2011-12-01

    A ZnO photonic amorphous diamond nanostructure was successfully synthesised using a feather barb of the Rosy-Faced Lovebird as supporting template via a facile sol-gel process. Different from ordered structures, an isotropic PBG around 500 nm was evidenced from reflectance spectra and an optical metallurgical microscopy image, which overlaps with the visible emission peak of ZnO. As a result, the inhibition of visible emission inside the PBG and the enhancement of UV emission at the PBG edges have both been observed, which is independent from the incident angle. Moreover, the rapid thermal annealing can also help improve the crystallinity of ZnO and raise the UV/visible emission ratio without affecting the structure. These results can be very useful for the study of the modification of the optical emission properties of ZnO and other semiconductor materials as well as research on ZnO random lasing.

  16. The fabrication of silicon nanostructures by focused-ion-beam implantation and TMAH wet etching

    NASA Astrophysics Data System (ADS)

    Sievilä, Päivi; Chekurov, Nikolai; Tittonen, Ilkka

    2010-04-01

    Local gallium implantation of silicon by a focused ion beam (FIB) has been used to create a mask for anisotropic tetramethylammonium hydroxide (TMAH) wet etching. The dependence of the etch stop properties of gallium-doped silicon on the implanted dose has been investigated and a dose of 4 × 1013 ions cm - 2 has been determined to be the threshold value for achieving observable etching resistance. Only a thin, approx. 50 nm, surface layer is found to be durable enough to serve as a mask with a high selectivity of at least 2000:1 between implanted and non-implanted areas. The combined FIB-TMAH process has been used to generate various types of 3D nanostructures including nanochannels separated by thin vertical sidewalls with aspect ratios up to 1:30, ultra-narrow (approx. 25 nm) freestanding bridges and cantilevers, and gratings with a resolution of 20 lines µm - 1.

  17. Novel approach to the fabrication of an artificial small bone using a combination of sponge replica and electrospinning methods

    NASA Astrophysics Data System (ADS)

    Kim, Yang-Hee; Lee, Byong-Taek

    2011-06-01

    In this study, a novel artificial small bone consisting of ZrO2-biphasic calcium phosphate/polymethylmethacrylate-polycaprolactone-hydroxyapatite (ZrO2-BCP/PMMA-PCL-HAp) was fabricated using a combination of sponge replica and electrospinning methods. To mimic the cancellous bone, the ZrO2/BCP scaffold was composed of three layers, ZrO2, ZrO2/BCP and BCP, fabricated by the sponge replica method. The PMMA-PCL fibers loaded with HAp powder were wrapped around the ZrO2/BCP scaffold using the electrospinning process. To imitate the Haversian canal region of the bone, HAp-loaded PMMA-PCL fibers were wrapped around a steel wire of 0.3 mm diameter. As a result, the bundles of fiber wrapped around the wires imitated the osteon structure of the cortical bone. Finally, the ZrO2/BCP scaffold was surrounded by HAp-loaded PMMA-PCL composite bundles. After removal of the steel wires, the ZrO2/BCP scaffold and bundles of HAp-loaded PMMA-PCL formed an interconnected structure resembling the human bone. Its diameter, compressive strength and porosity were approximately 12 mm, 5 MPa and 70%, respectively, and the viability of MG-63 osteoblast-like cells was determined to be over 90% by the MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay. This artificial bone shows excellent cytocompatibility and is a promising bone regeneration material.

  18. Automated spray coating process for the fabrication of large-area artificial opals on textured substrates.

    PubMed

    Sprafke, Alexander N; Schneevoigt, Daniela; Seidel, Sophie; Schweizer, Stefan L; Wehrspohn, Ralf B

    2013-05-01

    3D photonic crystals, such as opals, have been shown to have a high potential to increase the efficiency of solar cells by enabling advanced light management concepts. However, methods which comply with the demands of the photovoltaic industry for integration of these structures, i. e. the fabrication in a low-cost, fast, and large-scale manner, are missing up to now. In this work, we present the spray coating of a colloidal suspension on textured substrates and subsequent drying. We fabricated opaline films of much larger lateral dimensions and in much shorter times than what is possible using conventional opal fabrication methods. PMID:24104441

  19. Biological fabrication of nanostructured silicon-germanium photonic crystals possessing unique photoluminescent and electroluminescent properties

    NASA Astrophysics Data System (ADS)

    Rorrer, Gregory L.; Jeffryes, Clayton; Chang, Chih-hung; Lee, Doo-Hyoung; Gutu, Timothy; Jiao, Jun; Solanki, Raj

    2007-09-01

    Diatoms are single-celled algae which possess silica shells called "frustules" that contain periodic submicron scale features. A diatom cell culture process was used to fabricate a two-dimensional photonic crystal slab of Ge-doped biosilica that possessed 120 nm holes, 330 nm lattice constant, and dielectric constant of 8.5. This material was integrated into an electroluminescent (EL) device by spin coating of the frustules onto indium tin oxide, followed by atomic layer deposition of 400 nm hafnium silicate. No photonic band gap was predicted. However, the EL spectrum possessed resonant UV line emissions that were consistent with photonic band calculations. An EL band gap between 500-640 nm was also observed between blue and red EL line emissions. These EL characteristics have not been observed previously, and are unique to the diatom photonic crystal. This study represents a first step towards the realization of optoelectronic devices which utilize nanoscale components fabricated through cell culture.

  20. Poly (ethylene terephthalate) (PET) micro/nanostructures fabricated by nanoimprint and its applications

    NASA Astrophysics Data System (ADS)

    Wang, Xudi; Jin, Jian; Tang, Qisheng; Tian, Wenrui; Li, Xiaojun; Fu, Shaojun; Liao, Yanlin

    2010-10-01

    In this paper, we present a novel method for the fabrication of high density pattern in PET foils employing nanoimprint lithorgraphy. The temperature and pressure dependence on the imprinted pattern were investigated. Well resolved PET nanopatterns (sub-100nm resolution) were transferred successfully. It is observed that the grating with different trench depths will demonstrates corresponding changes of diffraction intensity distribution. The grating imprinted in PET foils could broader applications in the manufacture of nanophotonic structures owing to its excellent flexibility and transparency. Based on the optimized imprint process, a novel method for the fabrication of phase gratings and nanochannels is presented. This developed process can find broader applications in the manufacture of nanofluidic channels and other nanophotonic structures.

  1. Electrophysical properties of Si/SiO2 nanostructures fabricated by direct bonding

    NASA Astrophysics Data System (ADS)

    Gismatulin, A. A.; Kamaev, G. N.

    2016-06-01

    The results of experimental investigation of diode n ++- p ++-Si structures, which were fabricated by direct bonding and have tunneling-thin SiO2 with Si nanoclusters embedded into the interface, are presented. The memristive effect with bipolar switching is demonstrated. The introduction of Si nanoclusters into the dielectric reduces the randomness of formation of a conducting channel. Intermediate metastable states are observed in the current-voltage characteristics. This may prove to be important for multibit data storage.

  2. Self-assembled monolayer cleaning methods: Towards fabrication of clean high-temperature superconductor nanostructures

    SciTech Connect

    Kim, Sungwook; Chang, In Soon; McDevitt, John T.

    2005-04-11

    Although extensive amounts of research have been carried out on superconductor-normal metal-superconductor (SNS) electronic devices, the fabrication of superconductor SNS devices still remains difficult. Surface modification of high-temperature superconductors could be a way to control the interface of SNS electronic device fabrication. Here, we developed a cleaning method for thin films of high-temperature superconductor surface based on self-assembled monolayers. High-quality c-axis orientated YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (i.e., YBCO) and Y{sub 0.6}Ca{sub 0.4}Ba{sub 1.6}La{sub 0.4}Cu{sub 3}O{sub 7-{delta}} (i.e., TX-YBCO) thin films were deposited by standard laser ablation methods. YBCO/Au/YBCO and TX-YBCO/Au/TX-YBCO planar type junctions were fabricated by photolithography, focused-ion-beam milling, and ex situ sputter depositions. A 40-50 nm nanotrench was ion milled on the thin film by FIB, and a thin gold layer was deposited by an ex situ method on the nanotrench to connect the two separated high-temperature superconductor electrodes. SEM, AFM, and R vs T resistivity measurements were used to compare the corrosion layer formed in the interface of the SNS junctions with the SAM cleaned SNS junction. Evidence here suggests that the SAM cleaning method can be used to remove the degradation layer on the surface of cuprate superconductors. The obtained contact resistivity value (10{sup -8} {omega} cm{sup 2}) for a SNS junction with SAM treatment is comparable with that of SNS junctions fabricated by the in situ methods.

  3. Tuning the field distribution and fabrication of an Al@ZnO core–shell nanostructure for a SPR-based fiber optic phenyl hydrazine sensor

    NASA Astrophysics Data System (ADS)

    Tabassum, Rana; Kaur, Parvinder; Gupta, Banshi D.

    2016-05-01

    We report the fabrication and characterization of a surface plasmon resonance (SPR)-based fiber optic sensor that uses coatings of silver and aluminum (Al)-zinc oxide (ZnO) core–shell nanostructure (Al@ZnO) for the detection of phenyl hydrazine (Ph-Hyd). To optimize the volume fraction (f) of Al in ZnO and the thickness of the core–shell nanostructure layer (d), the electric field intensity along the normal to the multilayer system is simulated using the two-dimensional multilayer matrix method. The Al@ZnO core–shell nanostructure is prepared using the laser ablation technique. Various probes are fabricated with different values of f and an optimized thickness of core–shell nanostructure for the characterization of the Ph-Hyd sensor. The performance of the Ph-Hyd sensor is evaluated in terms of sensitivity. It is found that the Ag/Al@ZnO nanostructure core–shell-coated SPR probe with f = 0.25 and d = 0.040 μm possesses the maximum sensitivity towards Ph-Hyd. These results are in agreement with the simulated ones obtained using electric field intensity. In addition, the performance of the proposed probe is compared with that of probes coated with (i) Al@ZnO nanocomposite, (ii) Al nanoparticles and (iii) ZnO nanoparticles. It is found that the probe coated with an Al@ZnO core–shell nanostructure shows the largest resonance wavelength shift. The detailed mechanism of the sensing (involving chemical reactions) is presented. The sensor also manifests optimum performance at pH 7.

  4. Tuning the field distribution and fabrication of an Al@ZnO core-shell nanostructure for a SPR-based fiber optic phenyl hydrazine sensor.

    PubMed

    Tabassum, Rana; Kaur, Parvinder; Gupta, Banshi D

    2016-05-27

    We report the fabrication and characterization of a surface plasmon resonance (SPR)-based fiber optic sensor that uses coatings of silver and aluminum (Al)-zinc oxide (ZnO) core-shell nanostructure (Al@ZnO) for the detection of phenyl hydrazine (Ph-Hyd). To optimize the volume fraction (f) of Al in ZnO and the thickness of the core-shell nanostructure layer (d), the electric field intensity along the normal to the multilayer system is simulated using the two-dimensional multilayer matrix method. The Al@ZnO core-shell nanostructure is prepared using the laser ablation technique. Various probes are fabricated with different values of f and an optimized thickness of core-shell nanostructure for the characterization of the Ph-Hyd sensor. The performance of the Ph-Hyd sensor is evaluated in terms of sensitivity. It is found that the Ag/Al@ZnO nanostructure core-shell-coated SPR probe with f = 0.25 and d = 0.040 μm possesses the maximum sensitivity towards Ph-Hyd. These results are in agreement with the simulated ones obtained using electric field intensity. In addition, the performance of the proposed probe is compared with that of probes coated with (i) Al@ZnO nanocomposite, (ii) Al nanoparticles and (iii) ZnO nanoparticles. It is found that the probe coated with an Al@ZnO core-shell nanostructure shows the largest resonance wavelength shift. The detailed mechanism of the sensing (involving chemical reactions) is presented. The sensor also manifests optimum performance at pH 7. PMID:27079452

  5. Versatility of electrospinning in the fabrication of fibrous mat and mesh nanostructures of bismuth ferrite (BiFeO3) and their magnetic and photocatalytic activities.

    PubMed

    Bharathkumar, S; Sakar, M; K, Rohith Vinod; Balakumar, S

    2015-07-21

    This study demonstrates the fabrication of electrospun bismuth ferrite (BiFeO3/BFO) fiber mat and fibrous mesh nanostructures consisting of aligned and random fibers respectively. The formation of these one dimensional (1D) nanostructures was mediated by the drum and plate collectors in the electrospinning process that yielded aligned and random nanofibers of BFO respectively. The single phase and rhombohedral crystal structure of the fabricated 1D BFO nanostructures are confirmed through X-ray diffraction (XRD) studies. X-ray photoelectron spectroscopy (XPS) studies indicated that the fabricated fibers are stoichiometric BFO with native oxidation states +3. The surface texture and morphology are analyzed using the field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) techniques. The average size of fibers in mat and mesh nanostructures is found to be 200 nm and 150 nm respectively. The band gap energy of BFO mat and mesh deduced from their UV diffuse reflectance spectra (UV-DRS) was found to be 2.44 eV and 2.39 eV, respectively, which evidenced the improved visible light receptivity of BFO mesh compared to that of the mat. Magnetization studies using a super conducting quantum interference device (SQUID) magnetometer revealed the weak ferromagnetic properties of BFO mesh and mat nanostructures that could emerge due to the dimension induced suppression of cycloidal spin structures. The photocatalytic degradation properties of the fibrous mesh are found to be enhanced compared to that of the mat. This could be attributed to the reduced band gap energy and an improved semiconductor band-bending phenomenon in the mesh that favoured the transportation of excited charge carriers to the photocatalyst-dye interfaces and the production of more number of reactive species that lead to the effective degradation of the dye molecules. PMID:26083677

  6. Combining focused ion beam and atomic layer deposition in nanostructure fabrication

    NASA Astrophysics Data System (ADS)

    Han, Zhongmei; Vehkamäki, Marko; Leskelä, Markku; Ritala, Mikko

    2014-03-01

    Combining the strengths of atomic layer deposition (ALD) with focused ion beam (FIB) milling provides new opportunities for making 3D nanostructures with flexible choice of materials. Such structures are of interest in prototyping microelectronic and MEMS devices which utilize ALD grown thin films. As-milled silicon structures suffer from segregation and roughening upon heating, however. ALD processes are typically performed at 200-500 °C, which makes thermal stability of the milled structures a critical issue. In this work Si substrates were milled with different gallium ion beam incident angles and then annealed at 250 °C. The amount of implanted gallium was found to rapidly decrease with increasing incident angle with respect of surface normal, which therefore improves the thermal stability of the milled features. 60° incident angle was found as the best compromise with respect to thermal stability and ease of milling. ALD Al2O3 growth at 250 °C on the gallium FIB milled silicon was possible in all cases, even when segregation was taking place. ALD Al2O3 could be used both for creating a chemically uniform surface and for controlled narrowing of FIB milled trenches.

  7. Fabrication of a micro-omnifluidic device by omniphilic/omniphobic patterning on nanostructured surfaces.

    PubMed

    You, Inseong; Lee, Tae Geol; Nam, Yoon Sung; Lee, Haeshin

    2014-09-23

    We integrate the adhesive properties of marine mussels, the lubricating properties of pitcher plants, and the nonfouling properties of diatoms into nanostructured surfaces to develop a device called a micro-omnifluidic (μ-OF) system to solve the existing challenges in microfluidic systems. Unlike conventional poly(dimethylsiloxane)-based fluidic systems that are incompatible with most organic solvents, the μ-OF system utilizes a variety of solvents such as water, ethanol, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, n-hexane, 1,2-dichloroethane, acetic acid, 2-propanol, acetone, toluene, diesel oil, dioxane, gasoline oil, hexadecane, and xylene. The μ-OF system is based on a phenomenon called microchannel induction that spontaneously occurs when virtually all droplets of solvents are applied on omniphilically micropatterned regions of a slippery liquid-infused porous surface. Any solvents with surface tension greater than that of the lubricant (17.1 mN/m, Fluorinert FC-70) are able to repel the infused lubricant located on top of the omniphilic microlines, triggering controlled movement of the droplet by gravity along the microlines. We also demonstrated that the μ-OF system is reusable by the nonadsorption properties of the silicified layer. Due to the organic solvent compatibility, we were able to perform organic reactions with high portability and energy efficiency in operation. PMID:25188745

  8. An economic approach to fabricate photo sensor based on nanostructured ZnO thin films

    NASA Astrophysics Data System (ADS)

    Huse, Nanasaheb; Upadhye, Deepak; Sharma, Ramphal

    2016-05-01

    Nanostructural ZnO Thin Films have been synthesized by simple and economic Chemical Bath Deposition technique onto glass substrate with bath temperature at 60°C for 1 hour. Structural, Optical, Electrical and topographical properties of the prepared Thin Films were investigated by GIXRD, I-V Measurement System, UV-Visible Spectrophotometer and AFM respectively. Calculated lattice parameters are in good agreement with the standard JCPDS card (36-1451) values, exhibits Hexagonal Wurtzite crystal structure. I-V Measurement curve has shown ohmic nature in dark condition and responds to light illumination which reveals Photo sensor properties. After illumination of 60W light, decrease in resistance was observed from 110.9 KΩ to 104.4 KΩ. The change in current and calculated Photo sensitivity was found to be 3.51 µA and 6.3% respectively. Optical band gap was found to be 3.24 eV. AFM images revealed uniform deposition over entire glass substrate with 32.27 nm average roughness of the film.

  9. Thermally induced transformations of amorphous carbon nanostructures fabricated by electron beam induced deposition.

    PubMed

    Kulkarni, Dhaval D; Rykaczewski, Konrad; Singamaneni, Srikanth; Kim, Songkil; Fedorov, Andrei G; Tsukruk, Vladimir V

    2011-03-01

    We studied the thermally induced phase transformations of electron-beam-induced deposited (EBID) amorphous carbon nanostructures by correlating the changes in its morphology with internal microstructure by using combined atomic force microscopy (AFM) and high resolution confocal Raman microscopy. These carbon deposits can be used to create heterogeneous junctions in electronic devices commonly known as carbon-metal interconnects. We compared two basic shapes of EBID deposits: dots/pillars with widths from 50 to 600 nm and heights from 50 to 500 nm and lines with variable heights from 10 to 150 nm but having a constant length of 6 μm. We observed that during thermal annealing, the nanoscale amorphous deposits go through multistage transformation including dehydration and stress-relaxation around 150 °C, dehydrogenation within 150-300 °C, followed by graphitization (>350 °C) and formation of nanocrystalline, highly densified graphitic deposits around 450 °C. The later stage of transformation occurs well below commonly observed graphitization for bulk carbon (600-800 °C). It was observed that the shape of the deposits contribute significantly to the phase transformations. We suggested that this difference is controlled by different contributions from interfacial footprints area. Moreover, the rate of graphitization was different for deposits of different shapes with the lines showing a much stronger dependence of its structure on the density than the dots. PMID:21319745

  10. Characterization of pattern transfer in the fabrication of magnetic nanostructure arrays by block copolymer lithography

    NASA Astrophysics Data System (ADS)

    Kubo, T.; Parker, J. S.; Hillmyer, M. A.; Leighton, C.

    2007-06-01

    The authors report the fabrication of large-area antidot arrays using cylinder-forming polystyrene-polyisoprene-polylactide triblock terpolymer templates. 30nm antidots were generated after removal of the minority polymer component by aqueous degradation, oxygen reactive ion etching, and subsequent Ar ion beam milling to transfer the pattern to an underlying Ni80Fe20 film. Emphasis was placed on characterization of the pattern transfer, which was tracked using a combination of atomic force microscopy, magnetometry, and magnetotransport. It is demonstrated that variable temperature magnetometry and transport measurements are excellent probes of the progress of the ion milling into underlying magnetic layers.

  11. Fabrication of AIN Nano-Structures Using Polarity Control by High Temperature Metalorganic Chemical Vapor Deposition.

    PubMed

    Eom, Daeyong; Kim, Jinwan; Lee, Kyungjae; Jeon, Minhwan; Heo, Cheon; Pyeon, Jaedo; Nam, Okhyun

    2015-07-01

    This study investigates the crystallographic polarity transition of AIN layers grown by high temperature metalorganic chemical vapor deposition (HT-MOCVD), with varying trimethylaluminum (TMAI) pre-flow rates. AIN layers grown without TMAI pre-flow had a mixed polarity, consisting of Al- and N-polarity, and exhibited a rough surface. With an increasing rate of TMAI pre-flow, the AIN layer was changed to an Al-polarity, with a smooth surface morphology. Finally, AIN nano-pillars and nano-rods of Al-polarity were fabricated by etching a mixed polarity AIN layer using an aqueous KOH solution. PMID:26373093

  12. Electrochemical fabrication of Cu(OH) 2 and CuO nanostructures and their catalytic property

    NASA Astrophysics Data System (ADS)

    Ming, Hai; Pan, Keming; Liu, Yang; Li, Haitao; He, Xiaodie; Ming, Jun; Ma, Zheng; Kang, Zhenhui

    2011-07-01

    In this paper, we reported an anodization method for the fabrication of novel uniform Cu(OH) 2 nanowires, CuO nanoparticles, and CuO shuttle-like nanoparticles with advanced structures. The possible formation mechanism of Cu(OH) 2 nanowires, CuO nanoparticles, and CuO shuttle-like nanoparticles was proposed. The good catalytic properties of CuO nanoparticles converted from Cu(OH) 2 nanowires and the CuO shuttle-like nanoparticles were confirmed by evaluating their catalytic ability on the C-N cross coupling of amines with iodobenzene.

  13. Nano-structure fabrication for HgCdTe ultra-fast infrared sensors

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Wei; Yang, Jianrong; Chen, Yifang; Zhen, Honglou; Chen, Xiaoshuang; Lu, Wei

    2009-09-01

    High-speed infrared sensors are necessary for broad applications in optic fibre communications with high data capacity and high security and distance sensing by laser. In this paper, an ultra-fast infrared sensor with 100 nm ballistic channels has been proposed and successfully fabricated by electron beam lithography. The area of photosensitive surface is as large as 100 μm × 100 μm to ensure its high sensitivity. The principle is based on the ballistic transport of electrons in the nano-scale channels. The frequency is expected to be in the range of 10 GHz, one or two orders higher than conventional photovoltaic sensors.

  14. Fabrication of nanostructures on silicon carbide surface and microgroove sidewall using 800-nm femtosecond laser

    NASA Astrophysics Data System (ADS)

    Khuat, Vanthanh; Chen, Tao; Dao, Vanluu

    2015-07-01

    Nanoripples and nanoparticles have been fabricated on the surface of a silicon carbide sample with the irradiation of an 800-nm femtosecond laser in an underwater environment. When a linearly polarized laser was used, the nanoripples were perpendicular to the polarization direction of the incident laser, and the period of the nanoripples was dependent on the number of pulses. When a circularly polarized laser was used, nanoparticles with a diameter of approximately 80 nm were formed. In addition, we observed two kinds of nanoripples on the sidewall of the silicon carbide microgroove fabricated by femtosecond laser irradiation followed by chemical wet etching. When the polarization direction was aligned perpendicular to the writing direction, ripples parallel to the surface of the sample were formed. We attribute the formation of this kind of ripple to interference of the incident laser and the reflected wave. When the polarization direction was aligned parallel to the writing direction, the ripples are perpendicular to the surface of the sample. We attribute the formation of this kind of ripple to interference of incident laser and bulk electron plasma wave. A scanning electron microscope equipped with an energy dispersive X-ray spectroscope was employed to characterize the morphology of the structures.

  15. Plasmonic nanostructures fabricated using nanosphere-lithography, soft-lithography and plasma etching

    PubMed Central

    Makaryan, Taron; Enderle, Fabian; Wiedemann, Stefan; Plettl, Alfred; Marti, Othmar; Ziemann, Paul

    2011-01-01

    Summary We present two routes for the fabrication of plasmonic structures based on nanosphere lithography templates. One route makes use of soft-lithography to obtain arrays of epoxy resin hemispheres, which, in a second step, can be coated by metal films. The second uses the hexagonal array of triangular structures, obtained by evaporation of a metal film on top of colloidal crystals, as a mask for reactive ion etching (RIE) of the substrate. In this way, the triangular patterns of the mask are transferred to the substrate through etched triangular pillars. Making an epoxy resin cast of the pillars, coated with metal films, allows us to invert the structure and obtain arrays of triangular holes within the metal. Both fabrication methods illustrate the preparation of large arrays of nanocavities within metal films at low cost. Gold films of different thicknesses were evaporated on top of hemispherical structures of epoxy resin with different radii, and the reflectance and transmittance were measured for optical wavelengths. Experimental results show that the reflectivity of coated hemispheres is lower than that of coated polystyrene spheres of the same size, for certain wavelength bands. The spectral position of these bands correlates with the size of the hemispheres. In contrast, etched structures on quartz coated with gold films exhibit low reflectance and transmittance values for all wavelengths measured. Low transmittance and reflectance indicate high absorbance, which can be utilized in experiments requiring light confinement. PMID:22003451

  16. Fabrication of high-resolution nanostructures of complex geometry by the single-spot nanolithography method

    PubMed Central

    Anisimova, Margarita; Samardak, Aleksei; Ognev, Alexey

    2015-01-01

    Summary The paper presents a method for the high-resolution production of polymer nanopatterns with controllable geometrical parameters by means of a single-spot electron-beam lithography technique. The essence of the method entails the overexposure of a positive-tone resist, spin-coated onto a substrate where nanoscale spots are exposed to an electron beam with a dose greater than 0.1 pC per dot. A single-spot enables the fabrication of a nanoring, while a chain of spots placed at distance of 5–30 nm from each other allows the production of a polymer pattern of complex geometry of sub-10 nm resolution. We demonstrate that in addition to the naturally oxidized silicon substrates, gold-coated substrates can also successfully be used for the single-spot nanopattering technique. An explanation of the results related to the resist overexposure was demonstrated using Monte Carlo simulations. Our nanofabrication method significantly accelerates (up to 10 times) the fabrication rate as compared to conventional lithography on positive-tone resist. This technique can be potentially employed in the electronics industry for the production of nanoprinted lithography molds, etching masks, nanoelectronics, nanophotonics, NEMS and MEMS devices. PMID:25977869

  17. Fabrication and Characterization of Large-Area Unpatterned and Patterned Plasmonic Gold Nanostructures

    NASA Astrophysics Data System (ADS)

    Do, Minh Thanh; Tong, Quang Cong; Luong, Mai Hoang; Lidiak, Alexander; Ledoux-Rak, Isabelle; Lai, Ngoc Diep

    2016-05-01

    We report fabrication of Au nanoisland films on different substrates by thermally annealing a sputtered Au nanolayer and investigation of their structure, morphology, and optical properties. It was found that high-temperature annealing leads to transformation of the initial, continuous film into the forms of hillock and isolated island film. The final nanoisland films exhibit remarkably enhanced and localized plasmon resonance spectra with respect to the original sputtered film. The strong dependence of the resonance band spectra of the resulting structures on the annealing temperature and supporting substrate is presented and analyzed, suggesting that both of these factors could be used to tune the optical spectroscopic properties of such structures. Moreover, we propose and demonstrate a novel and effective approach for fabrication of patterned Au structures by thermally annealing the Au layer deposited onto modulated-surface substrates. The experimental results indicate that this method could become a promising approach for manufacturing plasmonic array structures, which have been extensively investigated and widely applied in many fields.

  18. Bilayer hybrid nanoimprinting method for fabricating embedded silver nanostructure arrays with enhanced photoluminescence

    NASA Astrophysics Data System (ADS)

    Choi, Jun-Hyuk; Sung, Sang-Keun; Kim, Chul-Hyun; Jung, Yeon-Ho; Jung, Joo-Yun; Jeong, Jun-Ho; Lee, Eung-Sug

    2014-01-01

    A bilayer hybrid nanoimprinting (NI) method was developed for fabricating embedded metal nanopatterns with greater processability and improved reliability for enhanced photoluminescence (PL) in optoelectronic devices. Bilayer hybrid NI consists of the following: (a) spin-coating ultraviolet (UV) and thermally curable NI resists in sequence, (b) high-pressure thermal NI and UV exposure while maintaining the stamp in a pressed position, and (c) silver (Ag) deposition and lift-off using a thermal NI resist on the upper surface to create embedded Ag nanoarrays. Reference samples with no Ag nanopatterns and with protruding Ag dot-shaped nanopatterns were also fabricated for comparison. The transmittance and PL of all samples were measured. All samples containing Ag nanopatterns exhibited improved PL compared with reference samples with no Ag. For all pattern sizes, the samples with the embedded Ag nanoarrays exhibited the highest PL; the relative PL enhancements compared with samples with Ag dot-shaped nanoarrays were 32.2%, 36.1%, and 62.7% for pattern sizes of 150, 200, and 265 nm, respectively.

  19. Cauda Equina-Derived Extracellular Matrix for Fabrication of Nanostructured Hybrid Scaffolds Applied to Neural Tissue Engineering

    PubMed Central

    Wen, Xiaoxiao; Wang, Yu; Guo, Zhiyuan; Meng, Haoye; Huang, Jingxiang; Zhang, Li; Zhao, Bin; Zhao, Qing

    2015-01-01

    Extracellular matrix (ECM) components have become important candidate materials for use as neural scaffolds for neural tissue engineering. In the current study, we prepared cauda equina-derived ECM materials for the production of scaffolds. Natural porcine cauda equina was decellularized using Triton X-100 and sodium deoxycholate, shattered physically, and made into a suspension by differential centrifugation. The decellularization procedure resulted in the removal of >94% of the nuclear material and preserved the extracellular collagen and sulfated glycosaminoglycan. Immunofluorescent staining confirmed the presence of collagen type I, laminin, and fibronectin in the ECM. The cauda equine-derived ECM was blended with poly(l-lactide-co-glycolide) (PLGA) to fabricate nanostructured scaffolds using electrospinning. The incorporation of the ECM increased the hydrophilicity of the scaffolds. Fourier transform infrared spectroscopy and multiphoton-induced autofluorescence images showed the presence of the ECM in the scaffolds. ECM/PLGA scaffolds were beneficial for the survival of Schwann cells compared with scaffolds consisting of PLGA alone, and the aligned fibers could regulate cell morphologic features by modulating cellular orientation. Axons in the dorsal root ganglia explants extended to a greater extent along ECM/PLGA compared with PLGA-alone fibers. The cauda equina ECM might be a promising material for forming scaffolds for use in neural tissue engineering. PMID:25366704

  20. Cauda equina-derived extracellular matrix for fabrication of nanostructured hybrid scaffolds applied to neural tissue engineering.

    PubMed

    Wen, Xiaoxiao; Wang, Yu; Guo, Zhiyuan; Meng, Haoye; Huang, Jingxiang; Zhang, Li; Zhao, Bin; Zhao, Qing; Zheng, Yudong; Peng, Jiang

    2015-03-01

    Extracellular matrix (ECM) components have become important candidate materials for use as neural scaffolds for neural tissue engineering. In the current study, we prepared cauda equina-derived ECM materials for the production of scaffolds. Natural porcine cauda equina was decellularized using Triton X-100 and sodium deoxycholate, shattered physically, and made into a suspension by differential centrifugation. The decellularization procedure resulted in the removal of >94% of the nuclear material and preserved the extracellular collagen and sulfated glycosaminoglycan. Immunofluorescent staining confirmed the presence of collagen type I, laminin, and fibronectin in the ECM. The cauda equine-derived ECM was blended with poly(l-lactide-co-glycolide) (PLGA) to fabricate nanostructured scaffolds using electrospinning. The incorporation of the ECM increased the hydrophilicity of the scaffolds. Fourier transform infrared spectroscopy and multiphoton-induced autofluorescence images showed the presence of the ECM in the scaffolds. ECM/PLGA scaffolds were beneficial for the survival of Schwann cells compared with scaffolds consisting of PLGA alone, and the aligned fibers could regulate cell morphologic features by modulating cellular orientation. Axons in the dorsal root ganglia explants extended to a greater extent along ECM/PLGA compared with PLGA-alone fibers. The cauda equina ECM might be a promising material for forming scaffolds for use in neural tissue engineering. PMID:25366704

  1. Bottom-up fabrication of graphene nanostructures on Ru\\left(10\\bar{1}0\\right)

    NASA Astrophysics Data System (ADS)

    Song, Junjie; Zhang, Han-jie; Cai, Yiliang; Zhang, Yuxi; Bao, Shining; He, Pimo

    2016-02-01

    Investigations on the bottom-up fabrication of graphene nanostructures with 10, 10’-dibromo-9, 9’-bianthryl (DBBA) as a precursor on Ru≤ft(10\\bar{1}0\\right) were carried out using scanning tunnelling microscopy (STM) and density functional theory (DFT) calculations. Upon annealing the sample at submonolayer DBBA coverage, N = 7 graphene nanoribbons (GNRs) aligned along the ≤ft[1\\bar{2}10\\right] direction form. Higher DBBA coverage and higher annealing temperature lead to the merging of GNRs into ribbon-like graphene nanoflakes with multiple orientations. These nanoflakes show different Moiré patterns, and their structures were determined by DFT simulations. The results showed that GNRs possess growth preference on the Ru≤ft(10\\bar{1}0\\right) substrate with a rectangular unit cell, and GNRs with armchair and zigzag boundaries are obtainable. Further DFT calculations suggest that the interaction between graphene and the substrate controls the orientations of the graphene overlayer and the growth of graphene on Ru≤ft(10\\bar{1}0\\right).

  2. Three novel electrochemical electrodes for the fabrication of conducting polymer/SWCNTs layered nanostructures and their thermoelectric performance

    NASA Astrophysics Data System (ADS)

    Shi, Hui; Liu, Congcong; Jiang, Qinglin; Xu, Jingkun; Lu, Baoyang; Jiang, Fengxing; Zhu, Zhengyou

    2015-06-01

    Single-walled carbon nanotubes (SWCNTs), PEDOT:PSS/SWCNTs, and SWCNTs/PEDOT:PSS nanofilms were used as working electrodes to electrodeposit polyaniline (PANI) in a mixed alcohol solution of isopropyl alcohol (IPA), boron trifluoride ethyl ether (BFEE), and polyethylene glycol (PEG). The thermoelectric (TE) performances of the resulting nanofilms were systematically investigated. SWCNTs/PEDOT:PSS/PANI nanofilms showed a relatively high electrical conductivity value of 232.0 S cm-1. The Seebeck coefficient was enhanced and exhibited the values of 33.8, 25.6, and 23.0 μV K-1 for the SWCNTs/PANI, PEDOT:PSS/SWCNTs/PANI, and SWCNTs/PEDOT:PSS/PANI films, respectively. The maximum power factor achieved was 12.3 μW m-1 K-2. This technique offers a facile and versatile approach to a class of layered nanostructures, and it may provide a general strategy for fabricating a new generation of conducting polymer/SWCNTs materials for further practical applications.

  3. Fast fabrication of nano-structured anti-reflection layers for enhancement of solar cells performance using plasma sputtering and infrared assisted roller embossing techniques.

    PubMed

    Liu, Shih-Jung; Liao, Che-Ting

    2012-02-27

    This paper reports the continuous fabrication of dual-side nano-structured anti-reflection protective layer for performance enhancement of solar cells using plasma sputtering and infrared assisted roller embossing techniques. Nano-structures were first deposited onto the surface of glass substrates using the plasma sputtering technique. After electroforming, a nickel master mold containing nano-array of 30 nm was obtained. The mold was then attached to the surfaces of the two metallic rollers in an infrared assisted roll-to-roll embossing facility. The embossing facility was used to replicate the nano-structures onto 60 μm thick polyethylene terephthalate (PET) films in the experiments. The embossed films were characterized using UV-vis spectrophotometer, atomic force microscope (AFM), and scanning electron microscope (SEM); its total conversion efficiency for solar cells was also measured by a solar simulator. The experimental results showed that the fabricated films could effectively reduce the reflectance and increase the conversion efficiency of solar cells. The proposed method shows great potential for fast fabrication of the anti-reflection protective layer of solar cells due to its simplicity and versatility. PMID:22418320

  4. Fabrication and characterization of transparent conducting titanium-zinc oxide nanostructured thin films

    NASA Astrophysics Data System (ADS)

    Lu, Zhou; Long, Lu; Zhong, Zhi-you; Hou, Jin; Yang, Chun-yong; Gu, Jin-hua; Long, Hao

    2016-03-01

    Nano transparent conducting titanium-zinc oxide (Ti-ZnO) thin films were prepared on glass substrates by radio frequency (RF) magnetron sputtering technique. The deposited films are characterized by X-ray diffraction (XRD), four-probe meter and UV-visible spectrophotometer. The effects of Ti-doping content on the structural, optical and electrical properties of the films are investigated. The XRD results show that the obtained films are polycrystalline with a hexagonal wurtzite structure and preferentially oriented in the (002) crystallographic direction. The structural and optoelectronic characteristics of the deposited films are subjected to the Ti-doping content. The Ti-ZnO sample fabricated with the Ti-doping content of 3% (weight percentage) possesses the best crystallinity and optoelectronic performance, with the highest degree of preferred (002) orientation of 99.87%, the largest crystallite size of 83.2 nm, the minimum lattice strain of 6.263×10-4, the highest average visible transmittance of 88.8%, the lowest resistivity of 1.18×10-3 Ω·cm and the maximum figure of merit ( FOM) of 7.08×103 Ω-1·cm-1. Furthermore, the optical bandgaps of the films are evaluated by extrapolation method and observed to be an increasing tendency with the increase of the Ti-doping content.

  5. High throughput fabrication of plasmonic nanostructures in nanofluidic pores for biosensing applications

    NASA Astrophysics Data System (ADS)

    Mazzotta, Francesco; Höök, Fredrik; Jonsson, Magnus P.

    2012-10-01

    One of the primary advantages of nanoscale sensors is that they often can provide conceptually new ways of performing sensing that are not feasible with their large-scale analogs. For example, the small size of nanoscale sensor elements, such as plasmonic metal nanoparticles, allows them to be combined with nanofluidic systems. Among the potential applications of such a combination is the efficient delivery of analyte to the sensor surface. With this in mind, in this work we look to address the challenge of creating and positioning nanoplasmonic sensor elements within nanofluidic pores. A scheme is presented that allows for the production of arrays of pores in a thin (220 nm) silicon nitride membrane with one plasmonic nanoparticle sensor element in each pore. The high throughput fabrication protocol is parallel and enables multiple sensor chips to be produced simultaneously, yet with accurate tuning of the dimension and shape of the nanoparticles. The presented system is shown to possess polarization-sensitive plasmonic resonances that can be tuned significantly in the visible wavelength range by just varying one process parameter. The thickness of the membrane could be optimized to minimize the influence of the optical membrane interference on the plasmonic readout. The sensitivity of the plasmon resonances to changes in refractive index, which forms the basis for using the system for biosensing, was found to be competitive with other nanoplasmonic sensors.

  6. Facile fabrication of MIL-103(Eu) porous coordination polymer nanostructures and their sorption and sensing properties.

    PubMed

    Liu, Qing; Yang, Ji-Min; Guo, Fan; Jin, Li-Na; Sun, Wei-Yin

    2016-04-01

    Nano/microscale lanthanide porous coordination polymer MIL-103(Eu) [Eu(BTB)] (H3BTB = 4,4',4''-benzene-1,3,5-triyl-tribenzoic acid) crystals have been fabricated at room temperature by a facile, convenient and environmentally friendly method. The structures of the products were confirmed by powder X-ray diffraction, and the crystal morphologies, including microrods, nanorods and nanospheres, were characterized by scanning electron microscopy. It is found that the addition of sodium acetate and the concentration of the reactants have an important impact on the morphology and size of the MIL-103(Eu) crystals. Gas adsorption measurements reveal that the products show high specific surface areas among the rare earth based coordination polymers and the MIL-103(Eu) nanorods can selectively adsorb CO2 over N2 under ambient conditions. Furthermore, all the products exhibit red emission corresponding to the (5)D0→(7)F2 transition of the Eu(iii) ion, and MIL-103(Eu) nanorods display sensitive and selective sensing for Cu(ii) ions and acetone molecules in solution. PMID:26940895

  7. Characterization of hydrogen environment anisotropic thermal etching and application to GaN nanostructure fabrication

    NASA Astrophysics Data System (ADS)

    Kita, Ryo; Hachiya, Ryo; Mizutani, Tomoya; Furuhashi, Hiroki; Kikuchi, Akihiko

    2015-04-01

    We report a new GaN etching technique with high anisotropy involving a thermal decomposition reaction in a low-pressure H2 environment. A GaN microridge stripe structure (5 µm in width and 1.2 µm in height) with extremely smooth sidewalls was fabricated at 1,050 °C and a H2 pressure of 10 Pa for 15 min using a SiO2 mask. The activation energy of the vertical etching was calculated to be 62-77 kcal/mol. In the GaN nanoridge stripe structure, the side etching under the SiO2 mask was less than 5 nm in depth and showed top width and height of ˜40 and ˜180 nm, respectively. The sidewall was extremely smooth and tilted by ˜15° from the m-plane along the a-axis, while being slightly rough and tilted by ˜30° from the a-plane along the m-axis. The \\{ n\\bar{n}02\\} (n = 4,5,6,7) planes were relatively stable in this etching technique.

  8. 3D porous and ultralight carbon hybrid nanostructure fabricated from carbon foam covered by monolayer of nitrogen-doped carbon nanotubes for high performance supercapacitors

    NASA Astrophysics Data System (ADS)

    He, Shuijian; Hou, Haoqing; Chen, Wei

    2015-04-01

    3D porous and self-supported carbon hybrids are promising electrode materials for supercapacitor application attributed to their prominent properties such as binder-free electrode fabrication process, excellent electric conductivity and high power density etc. We present here a facile chemical vapor deposition method to fabricate a novel 3D flexible carbon hybrid nanostructure by growing a monolayer of nitrogen-doped carbon nanotubes on the skeleton of carbon foam (N-CNTs/CF) with Fe nanoparticle as catalyst. With such 3D porous, flexible and ultralight carbon nanostructure as binder-free electrode material, large surface area is available and fast ionic transport is facilitated. Moreover, the carbon-based network can provide excellent electronic conductivity. The electrochemical studies demonstrate that the supercapacitor constructed from the N-CNTs/CF hybrid exhibit high power density of 69.3 kW kg-1 and good stability with capacitance retention ration above 95% after cycled at 50 A g-1 for 5000 cycles. Therefore, the prepared porous N-CNTs/CF nanostructure is expected to be a type of excellent electrode material for electrical double layer capacitors.

  9. Self-Assembly of Crystalline Structures of Magnetic Core-Shell Nanoparticles for Fabrication of Nanostructured Materials.

    PubMed

    Xue, Xiaozheng; Wang, Jianchao; Furlani, Edward P

    2015-10-14

    A theoretical study is presented of the template-assisted formation of crystalline superstructures of magnetic-dielectric core-shell particles. The templates produce highly localized gradient fields and a corresponding magnetic force that guides the assembly with nanoscale precision in particle placement. The process is studied using two distinct and complementary computational models that predict the dynamics and energy of the particles, respectively. Both mono- and polydisperse colloids are studied, and the analysis demonstrates for the first time that although the particles self-assemble into ordered crystalline superstructures, the particle formation is not unique. There is a Brownian motion-induced degeneracy in the process wherein various distinct, energetically comparable crystalline structures can form for a given template geometry. The models predict the formation of hexagonal close packed (HCP) and face centered cubic (FCC) structures as well as mixed phase structures due to in-plane stacking disorders, which is consistent with experimental observations. The polydisperse particle structures are less uniform than the monodisperse particle structures because of the irregular packing of different-sized particles. A comparison of self-assembly using soft- and hard-magnetic templates is also presented, the former being magnetized in a uniform field. This analysis shows that soft-magnetic templates enable an order-of-magnitude more rapid assembly and much higher spatial resolution in particle placement than their hard-magnetic counterparts. The self-assembly method discussed is versatile and broadly applies to arbitrary template geometries and multilayered and multifunctional mono- and polydisperse core-shell particles that have at least one magnetic component. As such, the method holds potential for the bottom-up fabrication of functional nanostructured materials for a broad range of applications. This work provides unprecedented insight into the assembly

  10. Fabrication mechanism of nanostructured HA/TNTs biomedical coatings: an improvement in nanomechanical and in vitro biological responses.

    PubMed

    Ahmadi, Shahab; Riahi, Zohreh; Eslami, Aylar; Sadrnezhaad, S K

    2016-10-01

    In this paper, a mechanism for fabrication of nanostructured hydroxyapatite coating on TiO2 nanotubes is presented. Also, the physical, biological, and nanomechanical properties of the anodized Ti6Al4V alloy consisting TiO2 nanotubes, electrodeposited hydroxyapatite, and the hydroxyapatite/TiO2 nanotubes double layer coating on Ti6Al4V alloy implants are compared. Mean cell viability of the samples being 84.63 % for uncoated plate, 91.53 % for electrodeposited hydroxyapatite, and 94.98 % for hydroxyapatite/TiO2 nanotubes coated sample were in the acceptable range. Merely anodized prototype had the highest biocompatibility of 110 % with respect to the control sample. Bonding strength of hydroxyapatite deposit to the substrate increased from 12 ± 2 MPa to 25.4 ± 2 MPa using intermediate TiO2 nanotubes layer. Hardness and elastic modulus of the anodized surface were 956 MPa and 64.7 GPa, respectively. The corresponding values for hydroxyapatite deposit were approximately measured 44.3 MPa and 0.66 GPa, respectively, while the average obtained values for hardness (159.3 MPa) and elastic modulus (2.25 GPa) of the hydroxyapatite/TiO2 nanotubes double coating improved more than 30 % of the pure hydroxyapatite deposit. Friction coefficient (ξ) of the anodized surface was 0.32 ± 0.02. The calculated friction coefficient enhanced from 0.65 ± 0.04 for sole hydroxyapatite layer to the 0.46 ± 0.02 for hydroxyapatite/TiO2 nanotubes due to presence of nanotubular TiO2 intermediate layer. PMID:27582070

  11. Large Scale Laser Two-Photon Polymerization Structuring for Fabrication of Artificial Polymeric Scaffolds for Regenerative Medicine

    NASA Astrophysics Data System (ADS)

    Malinauskas, M.; Purlys, V.; Žukauskas, A.; Rutkauskas, M.; Danilevičius, P.; Paipulas, D.; Bičkauskaitė, G.; Bukelskis, L.; Baltriukienė, D.; Širmenis, R.; Gaidukevičiutė, A.; Bukelskienė, V.; Gadonas, R.; Sirvydis, V.; Piskarskas, A.

    2010-11-01

    We present a femtosecond Laser Two-Photon Polymerization (LTPP) system of large scale three-dimensional structuring for applications in tissue engineering. The direct laser writing system enables fabrication of artificial polymeric scaffolds over a large area (up to cm in lateral size) with sub-micrometer resolution which could find practical applications in biomedicine and surgery. Yb:KGW femtosecond laser oscillator (Pharos, Light Conversion. Co. Ltd.) is used as an irradiation source (75 fs, 515 nm (frequency doubled), 80 MHz). The sample is mounted on wide range linear motor driven stages having 10 nm sample positioning resolution (XY—ALS130-100, Z—ALS130-50, Aerotech, Inc.). These stages guarantee an overall travelling range of 100 mm into X and Y directions and 50 mm in Z direction and support the linear scanning speed up to 300 mm/s. By moving the sample three-dimensionally the position of laser focus in the photopolymer is changed and one is able to write complex 3D (three-dimensional) structures. An illumination system and CMOS camera enables online process monitoring. Control of all equipment is automated via custom made computer software "3D-Poli" specially designed for LTPP applications. Structures can be imported from computer aided design STereoLihography (stl) files or programmed directly. It can be used for rapid LTPP structuring in various photopolymers (SZ2080, AKRE19, PEG-DA-258) which are known to be suitable for bio-applications. Microstructured scaffolds can be produced on different substrates like glass, plastic and metal. In this paper, we present microfabricated polymeric scaffolds over a large area and growing of adult rabbit myogenic stem cells on them. Obtained results show the polymeric scaffolds to be applicable for cell growth practice. It exhibit potential to use it for artificial pericardium in the experimental model in the future.

  12. Large Scale Laser Two-Photon Polymerization Structuring for Fabrication of Artificial Polymeric Scaffolds for Regenerative Medicine

    SciTech Connect

    Malinauskas, M.; Purlys, V.; Zukauskas, A.; Rutkauskas, M.; Danilevicius, P.; Paipulas, D.; Bickauskaite, G.; Gadonas, R.; Piskarskas, A.; Bukelskis, L.; Baltriukiene, D.; Bukelskiene, V.; Sirmenis, R.; Gaidukeviciute, A.; Sirvydis, V.

    2010-11-10

    We present a femtosecond Laser Two-Photon Polymerization (LTPP) system of large scale three-dimensional structuring for applications in tissue engineering. The direct laser writing system enables fabrication of artificial polymeric scaffolds over a large area (up to cm in lateral size) with sub-micrometer resolution which could find practical applications in biomedicine and surgery. Yb:KGW femtosecond laser oscillator (Pharos, Light Conversion. Co. Ltd.) is used as an irradiation source (75 fs, 515 nm (frequency doubled), 80 MHz). The sample is mounted on wide range linear motor driven stages having 10 nm sample positioning resolution (XY--ALS130-100, Z--ALS130-50, Aerotech, Inc.). These stages guarantee an overall travelling range of 100 mm into X and Y directions and 50 mm in Z direction and support the linear scanning speed up to 300 mm/s. By moving the sample three-dimensionally the position of laser focus in the photopolymer is changed and one is able to write complex 3D (three-dimensional) structures. An illumination system and CMOS camera enables online process monitoring. Control of all equipment is automated via custom made computer software ''3D-Poli'' specially designed for LTPP applications. Structures can be imported from computer aided design STereoLihography (stl) files or programmed directly. It can be used for rapid LTPP structuring in various photopolymers (SZ2080, AKRE19, PEG-DA-258) which are known to be suitable for bio-applications. Microstructured scaffolds can be produced on different substrates like glass, plastic and metal. In this paper, we present microfabricated polymeric scaffolds over a large area and growing of adult rabbit myogenic stem cells on them. Obtained results show the polymeric scaffolds to be applicable for cell growth practice. It exhibit potential to use it for artificial pericardium in the experimental model in the future.

  13. Hole-mask colloidal nanolithography combined with tilted-angle-rotation evaporation: A versatile method for fabrication of low-cost and large-area complex plasmonic nanostructures and metamaterials

    PubMed Central

    Frank, Bettina; Neubrech, Frank; Zhang, Chunjie; Braun, Paul V; Giessen, Harald

    2014-01-01

    Summary Many nano-optical applications require a suitable nanofabrication technology. Hole-mask colloidal nanolithography has proven to be a low-cost and large-area alternative for the fabrication of complex plasmonic nanostructures as well as metamaterials. In this paper, we describe the fabrication process step by step. We manufacture a variety of different plasmonic structures ranging from simple nano-antennas over complex chiral structures to stacked composite materials for applications such as sensing. Additionally, we give details on the control of the nanostructure lateral density which allows for the multilayer-fabrication of complex nanostructures. In two accompanying movies, the fabrication strategy is explained and details are being demonstrated in the lab. The movies can be found at the website of Beilstein TV. PMID:24991494

  14. Mechanical design, fabrication, and test of biomimetic fish robot using LIPCA as artificial muscle

    NASA Astrophysics Data System (ADS)

    Wiguna, T.; Syaifuddin, M.; Park, Hoon C.; Heo, S.

    2006-03-01

    This paper presents a mechanical design, fabrication and test of biomimetic fish robot using the Lightweight Piezocomposite Curved Actuator (LIPCA). We have designed a mechanism for converting actuation of the LIPCA into caudal fin movement. This linkage mechanism consists of rack-pinion system and four-bar linkage. We also have tested four types of caudal fin in order to examine effect of different shape of caudal fin on thrust generation by tail beat. Subsequently, based on the caudal fin test, four caudal fins which resemble fish caudal fin shapes of ostraciiform, subcarangiform, carangiform and thunniform, respectively, are attached to the posterior part of the robotic fish. The swimming test using 300 V pp input with 1 Hz to 1.5 Hz frequency was conducted to investigate effect of changing tail beat frequency and shape of caudal fin on the swimming speed of the robotic fish. The maximum swimming speed was reached when the device was operated at its natural swimming frequency. At the natural swimming frequency 1 Hz, maximum swimming speeds of 1.632 cm/s, 1.776 cm/s, 1.612 cm/s and 1.51 cm/s were reached for ostraciiform-, subcarangiform-, carangiform- and thunniform-like caudal fins, respectively. Strouhal numbers, which are a measure of thrust efficiency, were calculated in order to examine thrust performance of the present biomimetic fish robot. We also approximated the net forward force of the robotic fish using momentum conservation principle.

  15. Oxygen vacancy mediated enhanced photo-absorption from ZnO(0001) nanostructures fabricated by atom beam sputtering

    NASA Astrophysics Data System (ADS)

    Solanki, Vanaraj; Joshi, Shalik R.; Mishra, Indrani; Kabiraj, D.; Mishra, N. C.; Avasthi, D. K.; Varma, Shikha

    2016-08-01

    The nanoscale patterns created on the ZnO(0001) surfaces during atom beam irradiation have been investigated here for their photo absorption response. Preferential sputtering, during irradiation, promotes Zn-rich zones that serve as the nucleation centers for the spontaneous creation of nanostructures. Nanostructured surfaces with bigger (78 nm) nanodots, displaying hexagonal ordering and long ranged periodic behavior, show higher photo absorption and a ˜0.09 eV reduced bandgap. These nanostructures also demonstrate higher concentration of oxygen vacancies which are crucial for these results. The enhanced photo-response, as observed here, has been achieved in the absence of any dopant elements.

  16. Optical fiber sensors based on nanostructured coatings fabricated by means of the layer-by-layer electrostatic self-assembly method

    NASA Astrophysics Data System (ADS)

    Arregui, Francisco J.; Matías, Ignacio R.; Claus, Richard O.

    2007-07-01

    The Layer-by-Layer Electrostatic Self-Assembly (ESA) method has been successfully used for the design and fabrication of nanostructured materials. More specifically, this technique has been applied for the deposition of thin films on optical fibers with the purpose of fabricating different types of optical fiber sensors. In fact, optical fiber sensors for measuring humidity, temperature, pH, hydrogen peroxide, glucose, volatile organic compounds or even gluten have been already experimentally demonstrated. The versatility of this technique allows the deposition of these sensing coatings on flat substrates and complex geometries as well. For instance, nanoFabry-Perots and microgratings have been formed on cleaved ends of optical fibers (flat surfaces) and also sensing coatings have been built onto long period gratings (cylindrical shape), tapered fiber ends (conical shape), biconically tapered fibers or even the internal side of hollow core fibers. Among the different materials used for the construction of these sensing nanostructured coatings, diverse types such as polymers, inorganic semiconductors, colorimetric indicators, fluorescent dyes, quantum dots or even biological elements as enzymes can be found. This technique opens the door to the fabrication of new types of optical fiber sensors.

  17. Biomimetic Method To Assemble Nanostructured Ag@ZnO on Cotton Fabrics: Application as Self-Cleaning Flexible Materials with Visible-Light Photocatalysis and Antibacterial Activities.

    PubMed

    Manna, Joydeb; Goswami, Srishti; Shilpa, Nagaraju; Sahu, Nivedita; Rana, Rohit K

    2015-04-22

    A bioinspired mineralization route to prepare self-cleaning cotton fabrics by functionalizing their surface with nanostructured Ag@ZnO is demonstrated herein. In a polyamine-mediated mineralization process, while the nucleation, organization and coating of ZnO is done directly from water-soluble zinc salts under mild conditions, the entrapped polyamine in the ZnO matrix acts as reducing agent to generate Ag(0) from Ag(I) at room temperature. The Ag@ZnO coated cotton fabrics are characterized by FESEM, HRTEM, XRD, and UV-vis-DRS to confirm the formation and coating of Ag@ZnO particles on individual threads of the fabric. The presence of Ag nanoparticles not only enables the ZnO-coated fabrics exhibiting improved photocatalytic property but also allows for visible-light-driven activities. Furthermore, it exhibits efficient antimicrobial activity against both Gram-positive and Gram-negative bacteria. Therefore, besides these multifunctional properties, the polyamine-mediated bioinspired approach is expected to pave way for functionalization of flexible substrates under mild conditions as desirable for the development and fabrication of smart, lightweight, and wearable devices for various niche applications. PMID:25823715

  18. Experimental and theoretical study of the optical and electrical properties of nanostructured indium tin oxide fabricated by oblique-angle deposition.

    PubMed

    Sood, Adam W; Poxson, David J; Mont, Frank W; Chhajed, Sameer; Cho, Jaehee; Schubert, E Fred; Welser, Roger E; Dhar, Nibir K; Sood, Ashok K

    2012-05-01

    Oblique-angle deposition of indium tin oxide (ITO) is used to fabricate optical thin-film coatings with a porous, columnar nanostructure. Indium tin oxide is a material that is widely used in industrial applications because it is both optically transparent and electrically conductive. The ITO coatings are fabricated, using electron-beam evaporation, with a range of deposition angles between 0 degrees (normal incidence) and 80 degrees. As the deposition angle increases, we find that the porosity of the ITO film increases and the refractive index decreases. We measure the resistivity of the ITO film at each deposition angle, and find that as the porosity increases, the resistivity increases superlinearly. A new theoretical model is presented to describe the relationship between the ITO film's resistivity and its porosity. The model takes into account the columnar structure of the film, and agrees very well with the experimental data. PMID:22852330

  19. Fabrication and characterization of a nanostructured TiO2/In2S3-Sb2S3/CuSCN extremely thin absorber (eta) solar cell

    NASA Astrophysics Data System (ADS)

    Huerta-Flores, Alí M.; García-Gómez, Nora A.; de la Parra-Arciniega, Salomé M.; Sánchez, Eduardo M.

    2016-08-01

    In this work we report the successful assembly and characterization of a TiO2/In2S3-Sb2S3/CuSCN extremely thin absorber solar cell. Nanostructured TiO2 deposited by screen printing on an ITO substrate was used as an n-type electrode. An ∼80 nm extremely thin layer of the system In2S3-Sb2S3 deposited by successive ionic layer adsorption and a reaction (silar) method was used as an absorber. The voids were filled with p-type CuSCN and the entire assembly was completed with a gold contact. The solar cell fabricated with this heterostructure showed an energy conversion efficiency of 4.9%, which is a promising result in the development of low cost and simple fabrication of solar cells.

  20. Fabrication of nano-structures on glass substrate by modified nano-imprint patterning with a plasma-induced surface-oxidized Cr mask

    NASA Astrophysics Data System (ADS)

    Lee, So Hee; Lee, Su Yeon; Lee, Seong Eui; Lee, Heon; Lee, Hee Chul

    2014-03-01

    In this study, we introduce a process for fabrication of nano-sized structural arrays on glass using modified nano-imprint patterning. A PVC (polyvinyl chloride) stamp was prepared by hot embossing, and a Cr-oxide-pattern etch-mask was used. The etch-mask was formed by oxidizing the surface of exposed Cr region by oxygen plasma treatment at room temperature. The fabrication of the etch-mask was conducted by immersing the locally oxidized Cr pattern in resin remover and Cr-etchant. The residual UV resin and un-oxidized Cr pattern were selectively removed, resulting in the obvious array of Cr-oxide etch-mask-pattern. The array of glass nano-structures was formed by reactive ion etching (RIE) using CF4 and Ar gas discharge. After removing the Cr-oxide mask, the final nano-structure had a height of 40 nm and a diameter of 170 nm, which was slightly less than the diameter of the original master-mold. The plasma treatment gave rise to a rough glass surface with root-mean-square (RMS) roughness of 29.25 nm, while that of bare glass was 0.66 nm. A high optical transmittance due to reduction in reflectance was observed at the plasma-treated rough surface, as well as for the array of nano-structures. The highest measured optical transmittance was 97.2% at a wavelength of 550 nm; an increase of about 7.2% compared to bare glass.

  1. Electroassisted codeposition of sol-gel derived silica nanocomposite directs the fabrication of coral-like nanostructured porous gold.

    PubMed

    Farghaly, Ahmed A; Collinson, Maryanne M

    2014-05-13

    Herein, we report on a one-step coelectrodeposition method to form gold-silica nanocomposite materials from which high surface area nanostructured gold electrodes can be produced. The as-prepared Au-SiO2 films possess an interconnected three-dimensional porous framework with different silica-gold ratios depending on the deposition solutions and parameters. Chemical etching of the nanocomposite films using hydrofluoric acid resulted in the formation of nanostructured porous gold films with coral-like structures and pores in the nanometer range. The cross-linkage of the gold coral branches resulted in the generation of a porous framework. X-ray photoelectron spectroscopy confirms the complete removal of silica. Well-controlled surface area enhancement, film thickness, and morphology were achieved by manipulating the deposition parameters, such as potential, time, and gold ion and sol-gel monomer concentrations in the deposition solution. An enhancement in the surface area of the electrode up to 57 times relative to the geometric area has been achieved. The thickness of the as-prepared Au-SiO2 nanocomposite films is relatively high and varied from 8 to 15 μm by varying the applied deposition potential while the thickness of the coral-like nanostructured porous gold films ranged from 0.22 to 2.25 μm. A critical sol-gel monomer concentration (CSGC) was determined at which the deposited silica around the gold coral was able to stabilize the coral-like gold nanostructures, while below the CSGC, the coral-like gold nanostructures were unstable and the surface area of the nanostructured porous gold electrodes decreased. PMID:24766096

  2. Application of glucose as a green capping agent and reductant to fabricate CuI micro/nanostructures

    SciTech Connect

    Tavakoli, Farnosh; Salavati-Niasari, Masoud; Ghanbari, Davood; Saberyan, Kamal; Hosseinpour-Mashkani, S. Mostafa

    2014-01-01

    Graphical abstract: - Highlights: • CuI nanostructures were prepared via a simple precipitation method. • Glucose as a green capping agent and reductant was applied. • The effect of glucose concentration on the morphology of CuI was investigated. • According to XRD results, pure cubic phase CuI have been formed by using glucose. - Abstract: In this work, CuI micro/nanostructures have been successfully prepared via a simple precipitation route at room temperature. By using glucose as a clean reducing agent with different concentrations, CuI micro/nanostructures with various morphologies were obtained. Besides glucose, Na{sub 2}SO{sub 3}, KBH{sub 4} and N{sub 2}H{sub 4}·H{sub 2}O have been applied as reductant. X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectroscopy, X-ray energy dispersive spectroscopy (EDS) and Fourier transformed infrared (FT-IR) spectroscopy were used to characterize the as-produced CuI micro/nanostructures. According to the XRD results, it was found that pure cubic phase CuI have been formed by using glucose.

  3. Fabrication of MoS2 nanosheet@TiO2 nanotube hybrid nanostructures for lithium storage.

    PubMed

    Xu, Xin; Fan, Zhaoyang; Ding, Shujiang; Yu, Demei; Du, Yaping

    2014-05-21

    MoS2 nanosheet@TiO2 nanotube hybrid nanostructures were successfully prepared by a facile two-step method: prefabrication of porous TiO2 nanotubes based on a sol-gel method template against polymeric nanotubes, and then assembly of MoS2 nanoclusters that consist of ultrathin nanosheets through a solvothermal process. These hybrid nanostructures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) analysis. When evaluated as an electrode material for lithium ion batteries, the results of the electrochemical test show that the unique MoS2 nanosheet@TiO2 nanotube hybrid nanostructures exhibit outstanding lithium storage performances with high specific capacity and excellent rate capability. The smart architecture of the MoS2 nanosheet@TiO2 nanotube hybrid nanostructures makes a prominent contribution to the excellent electrochemical performance. PMID:24687092

  4. Fabrication

    NASA Technical Reports Server (NTRS)

    Angel, Roger; Helms, Richard; Bilbro, Jim; Brown, Norman; Eng, Sverre; Hinman, Steve; Hull-Allen, Greg; Jacobs, Stephen; Keim, Robert; Ulmer, Melville

    1992-01-01

    What aspects of optical fabrication technology need to be developed so as to facilitate existing planned missions, or enable new ones? Throughout the submillimeter to UV wavelengths, the common goal is to push technology to the limits to make the largest possible apertures that are diffraction limited. At any one wavelength, the accuracy of the surface must be better than lambda/30 (rms error). The wavelength range is huge, covering four orders of magnitude from 1 mm to 100 nm. At the longer wavelengths, diffraction limited surfaces can be shaped with relatively crude techniques. The challenge in their fabrication is to make as large as possible a reflector, given the weight and volume constraints of the launch vehicle. The limited cargo diameter of the shuttle has led in the past to emphasis on deployable or erectable concepts such as the Large Deployable Reflector (LDR), which was studied by NASA for a submillimeter astrophysics mission. Replication techniques that can be used to produce light, low-cost reflecting panels are of great interest for this class of mission. At shorter wavelengths, in the optical and ultraviolet, optical fabrication will tax to the limit the most refined polishing methods. Methods of mechanical and thermal stabilization of the substrate will be severely stressed. In the thermal infrared, the need for large aperture is tempered by the even stronger need to control the telescope's thermal emission by cooled or cryogenic operation. Thus, the SIRTF mirror at 1 meter is not large and does not require unusually high accuracy, but the fabrication process must produce a mirror that is the right shape at a temperature of 4 K. Future large cooled mirrors will present more severe problems, especially if they must also be accurate enough to work at optical wavelengths. At the very shortest wavelengths accessible to reflecting optics, in the x-ray domain, the very low count fluxes of high energy photons place a premium on the collecting area. It is

  5. Rapid fabrication of self-ordered porous alumina with 10-/sub-10-nm-scale nanostructures by selenic acid anodizing.

    PubMed

    Nishinaga, Osamu; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O

    2013-01-01

    Anodic porous alumina has been widely investigated and used as a nanostructure template in various nanoapplications. The porous structure consists of numerous hexagonal cells perpendicular to the aluminum substrate and each cell has several tens or hundreds of nanoscale pores at its center. Because the nanomorphology of anodic porous alumina is limited by the electrolyte during anodizing, the discovery of additional electrolytes would expand the applicability of porous alumina. In this study, we report a new self-ordered nanoporous alumina formed by selenic acid (H2SeO4) anodizing. By optimizing the anodizing conditions, anodic alumina possessing 10-nm-scale pores was rapidly assembled (within 1 h) during selenic acid anodizing without any special electrochemical equipment. Novel sub-10-nm-scale spacing can also be achieved by selenic acid anodizing and metal sputter deposition. Our new nanoporous alumina can be used as a nanotemplate for various nanostructures in 10-/sub-10-nm-scale manufacturing. PMID:24067318

  6. Nanostructured Ti6Al4V alloy fabricated using modified alkali-heat treatment: Characterization and cell adhesion.

    PubMed

    Su, Yingmin; Komasa, Satoshi; Sekino, Tohru; Nishizaki, Hiroshi; Okazaki, Joji

    2016-02-01

    In order to optimize the creation of a nanostructured surface on Ti6Al4V titanium alloy, an alkali treatment was performed using a 10-M NaOH solution at various temperatures (30, 40, 50, and 60°C) so as to determine the optimal temperature. This was combined with subsequent heat treatments (200, 400, 600, and 800°C) in air. The effects of different temperatures for the latter treatments on the nanostructure surface and the initial cell adhesion were evaluated, and the optimal temperature of the alkali solution was found to be 30°C. Further, the nanotopography, surface chemistry, and surface roughness of the nanoporous structure were retained after heat treatments performed at 200, 400, and 600°C, and only the phase structure was altered. The amorphous sodium titanate phase, the content of which increased with increased heat-treatment temperature, may have played a role in promoting cell adhesion on the nanoporous surface. However, heat treatment at 800°C did not enhance the cell-surface attachment. Rather, the nanostructure degraded significantly with the reappearance of Al and V. PMID:26652415

  7. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

    PubMed Central

    Yuan, Liang (Leon); Herman, Peter R.

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

  8. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors.

    PubMed

    Yuan, Liang Leon; Herman, Peter R

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems. PMID:26922872

  9. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors

    NASA Astrophysics Data System (ADS)

    Yuan, Liang (Leon); Herman, Peter R.

    2016-02-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems.

  10. Fabrication of dielectric and metallo-dielectric 3D nanostructures by direct laser writing and electroless plating

    NASA Astrophysics Data System (ADS)

    Radke, André; Wolff, Frank; Giessen, Harald; Klotzbücher, Thomas

    2010-02-01

    Direct laser writing via two-photon absorption allows the fabrication of three-dimensional dielectric structures with submicron resolution by tightly focusing ultrashort laser pulses into a photo-sensitive material with a high-resolution microscope objective and scanning the laser focus relative to the material. Woodpile photonic crystals fabricated with this method show a characteristic dip in transmission at near-infrared wavelengths. The spectral position of this transmission dip scales with the grating period of the fabricated crystals. Metallo-dielectric structures can be obtained by first fabricating dielectric templates with direct laser writing and subsequently coating the templates with a thin conformal metal film by electroless plating. Contiguous and conducting silver films can be deposited even on convoluted 3D geometries.

  11. Nanostructured titanium-silver coatings with good antibacterial activity and cytocompatibility fabricated by one-step magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Bai, Long; Hang, Ruiqiang; Gao, Ang; Zhang, Xiangyu; Huang, Xiaobo; Wang, Yueyue; Tang, Bin; Zhao, Lingzhou; Chu, Paul K.

    2015-11-01

    Bacterial infection and loosing are serious complications for biomedical implants in the orthopedic, dental, and other biomedical fields and the ideal implants should combine good antibacterial ability and bioactivity. In this study, nanostructured titanium-silver (Ti-Ag) coatings with different Ag contents (1.2 to 21.6 at%) are prepared on Ti substrates by magnetron sputtering. As the Ag concentration is increased, the coatings change from having dense columnar crystals to sparse ones and eventually no columnar structure. The Ti-Ag coatings can effectively kill Staphylococcus aureus during the first few days and remain moderately antibacterial after immersion for 75 days. Compared to pure Ti, the Ti-Ag coatings show good cytocompatibility as indicated by good osteoblast adhesion, proliferation, intracellular total protein synthesis, and alkaline phosphatase (ALP) activity. In addition, cell spreading, collagen secretion, and extracellular matrix mineralization are promoted on the coatings with the proper Ag contents due to the nanostructured morphological features. Our results indicate that favorable antibacterial activity and osseointegration ability can be simultaneously achieved by regulating the Ag contents in Ti-Ag coatings.

  12. Rapid fabrication of self-ordered porous alumina with 10-/sub-10-nm-scale nanostructures by selenic acid anodizing

    PubMed Central

    Nishinaga, Osamu; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

    2013-01-01

    Anodic porous alumina has been widely investigated and used as a nanostructure template in various nanoapplications. The porous structure consists of numerous hexagonal cells perpendicular to the aluminum substrate and each cell has several tens or hundreds of nanoscale pores at its center. Because the nanomorphology of anodic porous alumina is limited by the electrolyte during anodizing, the discovery of additional electrolytes would expand the applicability of porous alumina. In this study, we report a new self-ordered nanoporous alumina formed by selenic acid (H2SeO4) anodizing. By optimizing the anodizing conditions, anodic alumina possessing 10-nm-scale pores was rapidly assembled (within 1 h) during selenic acid anodizing without any special electrochemical equipment. Novel sub-10-nm-scale spacing can also be achieved by selenic acid anodizing and metal sputter deposition. Our new nanoporous alumina can be used as a nanotemplate for various nanostructures in 10-/sub-10-nm-scale manufacturing. PMID:24067318

  13. Fabrication of fully dense nanostructured MnBi magnet by hot compaction of cryo-milled powders

    NASA Astrophysics Data System (ADS)

    Hadjipanayis, George; Neelam, Venkata; Gabay, Alex; Li, Wang

    2013-03-01

    Recently, rare-earth-free permanent magnets (REFPMs) have attracted much attention globally owing to rare-earth metal crisis and high cost. Among the REFPMs, MnBi is a potential candidate due to its unusual large magnetocrystalline anisotropy (K ~ 107 erg/cc) and positive temperature of coefficient of coercivity. In this work, we report for the first time a novel processing method that combines the cryo-milling with hot compaction to produce fully dense bulk nanostructured MnBi magnet. The effect of cryo-milling on particle size, phase formation, and magnetic properties of MnBi has been studied in detail. Also, the microstructural and magnetic properties of bulk nanostructured MnBi magnet were investigated. Adoption of cryo-milling results in nanocrystalline powders with particle size of 400-500 nm. Large coercivity (Hc) values of 18.5 kOe, and 12.9 kOe were obtained in cryo-milled powders and hot compacted magnet respectively. The MnBi magnet shows a large positive temperature coefficient of Hc and the Hc reaches a value of more than 30 kOe above 450 K. The work was supported by Siemens.

  14. Production of nanostructures on bulk metal samples by laser ablation for fabrication of low-reflective surfaces

    NASA Astrophysics Data System (ADS)

    Hopp, Béla; Smausz, Tomi; Csizmadia, Tamás; Vass, Csaba; Tápai, Csaba; Kiss, Bálint; Ehrhardt, Martin; Lorenz, Pierre; Zimmer, Klaus

    2013-11-01

    Nanostructure formation on bulk noble metals (copper, gold and silver) by a femtosecond laser was studied aiming at the production of low-reflectivity surfaces. The target surface was irradiated with the beam of a 775 nm wavelength and 150 fs pulse duration Ti:sapphire laser. The fluence was in the 16-2000 mJ/cm2 range, while the average pulse number was varied between 10 and 1000 depending on the scanning speed of the sample stage. The reflectivity of the treated surfaces was measured with a visible-near-infrared microspectrometer in the 450-800 nm range, while the morphology was studied with a scanning electron microscope. A strong correlation was found between the decreasing reflectivity and the nanostructure formation on the irradiated surface; however, the morphology of silver significantly differed from those of copper and gold. For the two latter metals a dense coral-like structure was found probably as a result of cluster condensation in the ablation plume followed by diffusion-limited aggregation. In the case of silver the surface was covered by nanodroplets, which formation was probably influenced by the ‘spitting’ caused by ambient oxygen absorption in the molten silver followed by its fast release during the resolidification.

  15. Use of Synergistic Interactions to Fabricate Strong, Tough, and Conductive Artificial Nacre Based on Graphene Oxide and Chitosan.

    PubMed

    Wan, Sijie; Peng, Jingsong; Li, Yuchen; Hu, Han; Jiang, Lei; Cheng, Qunfeng

    2015-10-27

    Graphene is the strongest and stiffest material, leading to the development of promising applications in many fields. However, the assembly of graphene nanosheets into macrosized nanocomposites for practical applications remains a challenge. Nacre in its natural form sets the "gold standard" for toughness and strength, which serves as a guide to the assembly of graphene nanosheets into high-performance nanocomposites. Here we show the strong, tough, conductive artificial nacre based on graphene oxide through synergistic interactions of hydrogen and covalent bonding. Tensile strength and toughness was 4 and 10 times higher, respectively, than that of natural nacre. The exceptional integrated strong and tough artificial nacre has promising applications in aerospace, artificial muscle, and tissue engineering, especially for flexible supercapacitor electrodes due to its high electrical conductivity. The use of synergistic interactions is a strategy for the development of high-performance nanocomposites. PMID:26352293

  16. The design, fabrication and characterization of controlled-morphology nanomaterials and functional planar molecular nanocluster-based nanostructures

    NASA Astrophysics Data System (ADS)

    Khomutov, Gennady B.; Kislov, Vladimir V.; Gainutdinov, Radmir V.; Gubin, Sergey P.; Obydenov, Alexander Yu.; Pavlov, Stanislav A.; Sergeev-Cherenkov, Andrey N.; Soldatov, Eugene S.; Tolstikhina, Alla L.; Trifonov, Artem S.

    2003-06-01

    New nanofabrication methods based on the monolayer techniques, biomimetic principles, interface reactions and interactions have been developed. The formation and deposition of the mixed Langmuir monolayers composed of inert amphiphile matrix and guest ligand-stabilized metal-core nanocluster molecules allowed to obtain ordered stable reproducible planar monomolecular nanocluster-based nanostructures on solid substrates. The decomposition of similar metal-organic precursor compounds in the mixed Langmuir monolayers at the gas-liquid interface resulted in the initiation of two-dimensional growth of inorganic nanoparticles in the plain of monolayer. Gold and iron-containing nanoparticles were synthesized and characterized by scanning probe microscopy and transmission electron microscopy techniques. Effect of external applied field on the shape of two-dimensionally grown magnetic nanoparticles was observed. Effects related to discrete electron tunneling were observed in the monolayer structures of nanocluster molecules and gold nanoparticles at room temperature using STM.

  17. Fabrication of chain-like Mn 2O 3 nanostructures via thermal decomposition of manganese phthalate coordination polymers

    NASA Astrophysics Data System (ADS)

    Salavati-Niasari, Masoud; Mohandes, Fatemeh; Davar, Fatemeh; Saberyan, Kamal

    2009-12-01

    A novel manganese coordination polymer [Mn(Pht)(H 2O)] n as a precursor was obtained by chemical precipitation involving an aqueous solution of anhydrous manganese acetate and phthalate anion as a potential O-banded ligand. Fourier transform infrared (FT-IR) results proved that phthalate anions coordinate to metal cations as a chelating bidentate ligand, making polymeric structure. The Mn 2O 3 nanostructures have been prepared via thermal decomposition of as-prepared manganese phthalate polymers as precursor in the presence of oleic acid (OA) and triphenylphosphine (TPP) as a stabilizer and capping. Different approaches such as FT-IR, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied to characterize the products. TEM images and XRD analysis indicated that the as-synthesized chain-like Mn 2O 3 has a crystal phase of cubic syngony with a mean size of ˜40 nm.

  18. Fabrication of epitaxial CrO{sub 2} nanostructures directly on MgO(100) by pulsed laser deposition

    SciTech Connect

    Heinig, N. F.; Jalili, H.; Leung, K. T.

    2007-12-17

    Single-phase CrO{sub 2} nanostructured thin films have been grown directly on MgO(100) by pulsed laser ablation of a metallic Cr target in an O{sub 2} environment. X-ray diffraction shows that these films are strained and consist of CrO{sub 2} crystallites with two possible epitaxial relationships to the substrate; either CrO{sub 2}(110) or CrO{sub 2}(200) is parallel to MgO(100). Scanning electron microscopy and atomic force microscopy reveal orthogonally arranged nanoneedles and platelike structures (both 30-50 nm thick). X-ray photoemission confirms that the films are primarily CrO{sub 2} covered with a thin CrO{sub 3} overlayer and indicates its complete synthesis without any residual metallic Cr.

  19. Continuous fabrication of scalable 2-dimensional (2D) micro- and nanostructures by sequential 1D mechanical patterning processes

    NASA Astrophysics Data System (ADS)

    Ok, Jong G.; Panday, Ashwin; Lee, Taehwa; Jay Guo, L.

    2014-11-01

    We present a versatile and simple methodology for continuous and scalable 2D micro/nano-structure fabrication via sequential 1D patterning strokes enabled by dynamic nano-inscribing (DNI) and vibrational indentation patterning (VIP) as well as a `single-stroke' 2D patterning using a DNI tool in VIP.

  20. Continuous fabrication of scalable 2-dimensional (2D) micro- and nanostructures by sequential 1D mechanical patterning processes.

    PubMed

    Ok, Jong G; Panday, Ashwin; Lee, Taehwa; Jay Guo, L

    2014-12-21

    We present a versatile and simple methodology for continuous and scalable 2D micro/nano-structure fabrication via sequential 1D patterning strokes enabled by dynamic nano-inscribing (DNI) and vibrational indentation patterning (VIP) as well as a 'single-stroke' 2D patterning using a DNI tool in VIP. PMID:25363145

  1. LiFePO4 Nanostructures Fabricated from Iron(III) Phosphate (FePO4 x 2H2O) by Hydrothermal Method.

    PubMed

    Saji, Viswanathan S; Song, Hyun-Kon

    2015-01-01

    Electrode materials having nanometer scale dimensions are expected to have property enhancements due to enhanced surface area and mass/charge transport kinetics. This is particularly relevant to intrinsically low electronically conductive materials such as lithium iron phosphate (LiFePO4), which is of recent research interest as a high performance intercalation electrode material for Li-ion batteries. Many of the reported works on LiFePO4 synthesis are unattractive either due to the high cost of raw materials or due to the complex synthesis technique. In this direction, synthesis of LiFePO4 directly from inexpensive FePO4 shows promise.The present study reports LiFePO4 nanostructures prepared from iron (III) phosphate (FePO4 x 2H2O) by precipitation-hydrothermal method. The sintered powder was characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Inductive coupled plasma-optical emission spectroscopy (ICP-OES), and Electron microscopy (SEM and TEM). Two synthesis methods, viz. bulk synthesis and anodized aluminum oxide (AAO) template-assisted synthesis are reported. By bulk synthesis, micro-sized particles having peculiar surface nanostructuring were formed at precipitation pH of 6.0 to 7.5 whereas typical nanosized LiFePO4 resulted at pH ≥ 8.0. An in-situ precipitation strategy inside the pores of AAO utilizing the spin coating was utilized for the AAO-template-assisted synthesis. The template with pores filled with the precipitate was subsequently subjected to hydrothermal process and high temperature sintering to fabricate compact rod-like structures. PMID:26328435

  2. Fabrication and characterization of a magnetic micro-actuator based on deformable Fe-doped PDMS artificial cilium using 3D printing

    NASA Astrophysics Data System (ADS)

    Liu, Fengli; Alici, Gursel; Zhang, Binbin; Beirne, Stephen; Li, Weihua

    2015-03-01

    This paper proposes the use of a 3D extrusion printer to fabricate artificial magnetic cilium. The cilia are fabricated using polydimethylsiloxane (PDMS) doped with iron particles so that they remain slender and flexible. They can be driven by a magnetic field to closely mimic the behaviour of biological cilia. Doping iron particles to the polymers has already been done; however, to the best of our knowledge, printing such active and soft magnetic structures has not. The existing methods for manufacturing magnetic polymeric structures are complex and difficult to use for the fabrication of micro-sized high-aspect-ratio cilia. The 3D printing technique we propose here is simple and inexpensive compared to previously suggested fabrication methods. In this study, free-standing magnetic PDMS cilia were fabricated in different sizes up to 5 mm in length and 1 mm in width. The stress-strain curves of the PDMS cilia were experimentally obtained to quantify the effect of the concentration of the iron particles on the modulus of elasticity of the cilia. The higher the iron concentration, the higher the modulus of elasticity. We have quantified the characteristics of the cilia made of 40% w/w iron particles in PDMS. A single cilium (5 × 1 × 0.0035 mm) can output up to 27 μN blocking force under a magnetic field of 160 mT. These cilia can be used as a mixer in lap-on-chip applications and as the anchoring and propulsion legs of endoscopic capsule robots operating within the gastrointestinal tract of humans. Analytical expressions estimating the blocking force are established and compared with the experimental results.

  3. Fabrication of high aspect ratio tungsten nanostructures on ultrathin c-Si membranes for extreme UV applications

    NASA Astrophysics Data System (ADS)

    Delachat, F.; Le Drogoff, B.; Constancias, C.; Delprat, S.; Gautier, E.; Chaker, M.; Margot, J.

    2016-01-01

    In this work, we demonstrate a full process for fabricating high aspect ratio diffraction optics for extreme ultraviolet lithography. The transmissive optics consists in nanometer scale tungsten patterns standing on flat, ultrathin (100 nm) and highly transparent (>85% at 13.5 nm) silicon membranes (diameter of 1 mm). These tungsten patterns were achieved using an innovative pseudo-Bosch etching process based on an inductively coupled plasma ignited in a mixture of SF6 and C4F8. Circular ultra-thin Si membranes were fabricated through a state-of-the-art method using direct-bonding with thermal difference. The silicon membranes were sputter-coated with a few hundred nanometers (100-300 nm) of stress-controlled tungsten and a very thin layer of chromium. Nanoscale features were written in a thin resist layer by electron beam lithography and transferred onto tungsten by plasma etching of both the chromium hard mask and the tungsten layer. This etching process results in highly anisotropic tungsten features at room temperature. The homogeneity and the aspect ratio of the advanced pattern transfer on the membranes were characterized with scanning electron microscopy after focus ion beam milling. An aspect ratio of about 6 for 35 nm size pattern is successfully obtained on a 1 mm diameter 100 nm thick Si membrane. The whole fabrication process is fully compatible with standard industrial semiconductor technology.

  4. Fabrication of high aspect ratio tungsten nanostructures on ultrathin c-Si membranes for extreme UV applications.

    PubMed

    Delachat, F; Le Drogoff, B; Constancias, C; Delprat, S; Gautier, E; Chaker, M; Margot, J

    2016-01-15

    In this work, we demonstrate a full process for fabricating high aspect ratio diffraction optics for extreme ultraviolet lithography. The transmissive optics consists in nanometer scale tungsten patterns standing on flat, ultrathin (100 nm) and highly transparent (>85% at 13.5 nm) silicon membranes (diameter of 1 mm). These tungsten patterns were achieved using an innovative pseudo-Bosch etching process based on an inductively coupled plasma ignited in a mixture of SF6 and C4F8. Circular ultra-thin Si membranes were fabricated through a state-of-the-art method using direct-bonding with thermal difference. The silicon membranes were sputter-coated with a few hundred nanometers (100-300 nm) of stress-controlled tungsten and a very thin layer of chromium. Nanoscale features were written in a thin resist layer by electron beam lithography and transferred onto tungsten by plasma etching of both the chromium hard mask and the tungsten layer. This etching process results in highly anisotropic tungsten features at room temperature. The homogeneity and the aspect ratio of the advanced pattern transfer on the membranes were characterized with scanning electron microscopy after focus ion beam milling. An aspect ratio of about 6 for 35 nm size pattern is successfully obtained on a 1 mm diameter 100 nm thick Si membrane. The whole fabrication process is fully compatible with standard industrial semiconductor technology. PMID:26630379

  5. In Situ Fabrication of Reproducible YBCO/Au Planar Tunnel Junctions with an Artificial MgO Barrier

    NASA Astrophysics Data System (ADS)

    Furuyama, Masafumi; Iguchi, Ienari; Shirai, Koji; Kusumori, Takeshi; Ohtake, Hiroaki; Tomura, Shoji; Nasu, Masako

    1990-03-01

    The in situ fabrication of YBCO (YBa2Cu3Oy)/MgO/Au epitaxial planar tunnel junctions with a thin MgO barrier utilizing an electron-beam coevaporation technique is reported. The thickness of the MgO barrier is 3-12 nm and the tunnel resistance shows a strong dependence on barrier thickness. The fabricated tunnel junctions are highly reproducible and controllable. The observed tunnel characteristics contain the gap opening at about 20 mV and the anomaly around zero bias. The tunnel characteristics using the degraded films are also reported.

  6. Controllable fabrication of zinc borate hierarchical nanostructure on brucite surface for enhanced mechanical properties and flame retardant behaviors.

    PubMed

    Wang, Xuesong; Pang, Hongchang; Chen, Wendan; Lin, Yuan; Zong, Lishuai; Ning, Guiling

    2014-05-28

    A novel and efficient halogen-free composite flame retardant (CFR) consisting of a brucite core and a fine zinc borate [Zn6O(OH)(BO3)3] hierarchical nanostructure shell was designed and synthesized via a facile nanoengineering route. It had been demonstrated that this unique hybrid structure possessed a high BET specific surface area (65 m(2)/g) and could significantly enhance the interfacial interaction when mixing with ethylene-vinyl acetate (EVA). This improved the transfer of stress between CFR particles and EVA matrix and increased the viscosity of EVA/EVA blends, which was beneficial for droplet inhibition and char forming. The mechanical properties and flammability behaviors of the EVA/CFR blends had been compared with the EVA/physical mixture (PM, with the given proportion of brucite and Zn6O(OH)(BO3)3). The mechanical properties of EVA/CFR blends, especially the tensile strength (TS), presented a remarkable increase reaching at least a 20% increment. Meanwhile, with the same 45 wt % of fillers, the EVA/CFR formulation could achieve a limiting oxygen index (LOI) value of 33 (37.5 % higher than that of EVA/PM blends) and UL-94 V-0 rating. Moreover, the heat release rate (HRR), peak heat release rate (PHRR), total heat released (THR), smoke production rate (SPR) and mass loss rate (MLR) were considerably reduced, especially PHRR and SPR for EVA/CFR blends were reduced to 32%. According to this study, the design of fine structure might pave the way for the future development of halogen-free flame retardants combining both enhanced mechanical properties and excellent flame retardant behaviors. PMID:24813539

  7. Nanostructure copper oxocobaltate fabricated by co-precipitation route using copper and cobalt nitrate as precursors: characterization by combined diffuse reflectance and FT infrared spectra.

    PubMed

    Habibi, Mohammad Hossein; Rezvani, Zoya

    2014-09-15

    Nanostructure copper oxocobaltate has been fabricated by a co-precipitation route using copper and cobalt nitrate as precursors. The physicochemical properties of copper cobaltate have been characterized via X-ray powder diffractometry (XRD) and field emission scanning electron microscopy (FESEM). The X-ray diffraction patterns indicates the presence of a spinel crystalline phase, (Cu0.30Co0.70)Co2O4, copper oxocobaltate with face-centered cubic lattice and Fd3m space group. FESEM images also illustrated a typical hexagonal morphology with particle size 25 nm, showing a good nanoscale crystalline morphology, which corresponds well with their XRD results. The FTIR spectra confirmed the presence of hydroxyl groups bonded to the metals, stretching vibration of the cobalt-oxygen bond in an octahedral coordination and the characteristic band assigned to the vibration of Cu-O bond. UV-VIS diffuse reflectance spectrum shows a broad band over the whole visible range and broad band between 200 nm and 390 nm ascribed to the ligand to metal charge transfer. PMID:24793481

  8. Development and characterization of self-healing carbon fabric/ionomer composite through stitched polymeric artificial muscle

    NASA Astrophysics Data System (ADS)

    Gabriel, Mark Joseph

    Typical cracks in composite materials are hard to detect, because they may be very small or occur inside the material. This study investigates the development and characterization of carbon fiber and an ionomer, self-healing, laminate composite, enhanced with stitched artificial muscle elements. Although the carbon fiber is used as a structural reinforcement, the carbon fiber can also act as a resistive heating element in order to activate the healing elements in a Close-Then-Heal (CTH) approach. However in this study, hot air in an oven was used to activate the, SurlynRTM 8940, self-healing matrix. Artificial muscle was prepared from commercial fishing line to stitch reinforce the carbon laminate composite in the Z plane. Holes were drilled into the final composite and the muscle was stitched into the composite for active reinforcement. Differential scanning calorimetry was used to characterize the matrix and fishing line properties. The resulting smart composite was subjected to low velocity impact tests and consequential damage before healing in an oven, followed by three point bending flexure tests. Cracks in the carbon fiber reinforcement formed more easily than expected after impact because the holes were drilled to facilitate the muscle stitching. The matrix material could heal, but the reinforcement carbon could not. Several equipment issues and failures limited the amount of samples that could be created to continue testing with new parameters.

  9. Fabrication and electrical transport properties of binary Co-Si nanostructures prepared by focused electron beam-induced deposition

    SciTech Connect

    Porrati, F.; Huth, M.; Kaempken, B.; Terfort, A.

    2013-02-07

    CoSi-C binary alloys have been fabricated by focused electron beam-induced deposition by the simultaneous use of dicobaltoctacarbonyl, Co{sub 2}(CO){sub 8}, and neopentasilane, Si{sub 5}H{sub 12}, as precursor gases. By varying the relative flux of the precursors, alloys with variable chemical composition are obtained, as shown by energy dispersive x-ray analysis. Room temperature electrical resistivity measurements strongly indicate the formation of cobalt silicide and cobalt disilicide nanoclusters embedded in a carbonaceous matrix. Temperature-dependent electrical conductivity measurements show that the transport properties are governed by electron tunneling between neighboring CoSi or CoSi{sub 2} nanoclusters. In particular, by varying the metal content of the alloy, the electrical conductivity can be finely tuned from the insulating regime into the quasi-metallic tunneling coupling regime.

  10. Fabrication of α-Fe2O3@graphene nanostructures for enhanced gas-sensing property to ethanol

    NASA Astrophysics Data System (ADS)

    Liang, Shiming; Zhu, Junwu; Wang, Chao; Yu, Songtao; Bi, Huiping; Liu, Xiaoheng; Wang, Xin

    2014-02-01

    A simple and straightforward strategy was developed for anchoring α-Fe2O3 nanoparticles on graphene as gas sensor material. The XRD and TEM results indicate that graphene sheets are decorated with α-Fe2O3 nanoparticles with various diameters and shapes. To demonstrate the potential applications, we have fabricated gas sensors using the as-synthesized α-Fe2O3@graphene and investigated sensor activity for ethanol detection. The results show that an appropriate content of graphene dopant could effectively enhance the gas-sensing properties of α-Fe2O3 operated at different temperatures. Especially, the α-Fe2O3@graphene (contained 2 wt% of graphene) sensor exhibits better sensor performances in comparison with pure α-Fe2O3 counterpart, indicating the potential applications as sensor material toward ethanol detection.

  11. Optical nano artifact metrics using silicon random nanostructures

    PubMed Central

    Matsumoto, Tsutomu; Yoshida, Naoki; Nishio, Shumpei; Hoga, Morihisa; Ohyagi, Yasuyuki; Tate, Naoya; Naruse, Makoto

    2016-01-01

    Nano-artifact metrics exploit unique physical attributes of nanostructured matter for authentication and clone resistance, which is vitally important in the age of Internet-of-Things where securing identities is critical. However, expensive and huge experimental apparatuses, such as scanning electron microscopy, have been required in the former studies. Herein, we demonstrate an optical approach to characterise the nanoscale-precision signatures of silicon random structures towards realising low-cost and high-value information security technology. Unique and versatile silicon nanostructures are generated via resist collapse phenomena, which contains dimensions that are well below the diffraction limit of light. We exploit the nanoscale precision ability of confocal laser microscopy in the height dimension; our experimental results demonstrate that the vertical precision of measurement is essential in satisfying the performances required for artifact metrics. Furthermore, by using state-of-the-art nanostructuring technology, we experimentally fabricate clones from the genuine devices. We demonstrate that the statistical properties of the genuine and clone devices are successfully exploited, showing that the liveness-detection-type approach, which is widely deployed in biometrics, is valid in artificially-constructed solid-state nanostructures. These findings pave the way for reasonable and yet sufficiently secure novel principles for information security based on silicon random nanostructures and optical technologies. PMID:27578146

  12. Optical nano artifact metrics using silicon random nanostructures.

    PubMed

    Matsumoto, Tsutomu; Yoshida, Naoki; Nishio, Shumpei; Hoga, Morihisa; Ohyagi, Yasuyuki; Tate, Naoya; Naruse, Makoto

    2016-01-01

    Nano-artifact metrics exploit unique physical attributes of nanostructured matter for authentication and clone resistance, which is vitally important in the age of Internet-of-Things where securing identities is critical. However, expensive and huge experimental apparatuses, such as scanning electron microscopy, have been required in the former studies. Herein, we demonstrate an optical approach to characterise the nanoscale-precision signatures of silicon random structures towards realising low-cost and high-value information security technology. Unique and versatile silicon nanostructures are generated via resist collapse phenomena, which contains dimensions that are well below the diffraction limit of light. We exploit the nanoscale precision ability of confocal laser microscopy in the height dimension; our experimental results demonstrate that the vertical precision of measurement is essential in satisfying the performances required for artifact metrics. Furthermore, by using state-of-the-art nanostructuring technology, we experimentally fabricate clones from the genuine devices. We demonstrate that the statistical properties of the genuine and clone devices are successfully exploited, showing that the liveness-detection-type approach, which is widely deployed in biometrics, is valid in artificially-constructed solid-state nanostructures. These findings pave the way for reasonable and yet sufficiently secure novel principles for information security based on silicon random nanostructures and optical technologies. PMID:27578146

  13. Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures.

    PubMed

    Chen, Ruei-San; Tang, Chih-Che; Shen, Wei-Chu; Huang, Ying-Sheng

    2015-01-01

    Layer semiconductors with easily processed two-dimensional (2D) structures exhibit indirect-to-direct bandgap transitions and superior transistor performance, which suggest a new direction for the development of next-generation ultrathin and flexible photonic and electronic devices. Enhanced luminescence quantum efficiency has been widely observed in these atomically thin 2D crystals. However, dimension effects beyond quantum confinement thicknesses or even at the micrometer scale are not expected and have rarely been observed. In this study, molybdenum diselenide (MoSe2) layer crystals with a thickness range of 6-2,700 nm were fabricated as two- or four-terminal devices. Ohmic contact formation was successfully achieved by the focused-ion beam (FIB) deposition method using platinum (Pt) as a contact metal. Layer crystals with various thicknesses were prepared through simple mechanical exfoliation by using dicing tape. Current-voltage curve measurements were performed to determine the conductivity value of the layer nanocrystals. In addition, high-resolution transmission electron microscopy, selected-area electron diffractometry, and energy-dispersive X-ray spectroscopy were used to characterize the interface of the metal-semiconductor contact of the FIB-fabricated MoSe2 devices. After applying the approaches, the substantial thickness-dependent electrical conductivity in a wide thickness range for the MoSe2-layer semiconductor was observed. The conductivity increased by over two orders of magnitude from 4.6 to 1,500 Ω(-) (1) cm(-) (1), with a decrease in the thickness from 2,700 to 6 nm. In addition, the temperature-dependent conductivity indicated that the thin MoSe2 multilayers exhibited considerably weak semiconducting behavior with activation energies of 3.5-8.5 meV, which are considerably smaller than those (36-38 meV) of the bulk. Probable surface-dominant transport properties and the presence of a high surface electron concentration in MoSe2 are proposed

  14. Fabrication and Tailoring Plasmonic Properties of Two Dimensional Assemblies of Metal Nanostructures towards Engineering Novel Plasmonic Sensors

    NASA Astrophysics Data System (ADS)

    Ahamad, Nur Uddin

    Electromagnetic mechanism of enhancement, proposed to elucidate surface enhanced Raman scattering (SERS) and Surface enhanced fluorescence (SEF), was justified by studying distance dependent enhancement of SERS and SEF using 2D self-assembled spheroidal silver nanoparticles containing probe molecules. Spacer layer between the metal surface and the probe was created by layer-by-layer deposition of oppositely charged polyelectrolytes. A decreasing trend in SERS enhancement factor and an increasing trend in SEF enhancement factor with increasing separation distance were observed, which corroborate with proposed electromagnetic mechanism of SERS and SEF. In order to fabricate effective SERS substrates by exploiting hot spots, supported 2D assemblies of silver nanocubes (NCs) with controlled interparticles distance were fabricated using LB technique. Interparticles distance in such substrates was tailored by incorporation of NCs in phospholipid monolayers in Langmuir trough and optimizing lateral surface pressure during the film transfer onto a solid surface. However, to develop plasmonic sensors with high refractive index sensitivity (RIS), investigation was performed to optimize RIS of supported and colloidal silver NCs. The size of the NCs, RI of supporting dielectric substrate, and the monolayer surface pressure were used as variables in refractive index sensing optimization. It was found that high refractive index dielectric substrates, a passive molecular spacer and large angles of incidence facilitate the detection of plasmonic response of supported 2D assemblies of nanocubes. Furthermore, a simple and robust strategy was demonstrated for assembling silver NCs into 2D hierarchical structures (uniform rounded islands, branched-parallel chains) on LB films exploiting phase behaviors of multi-components lipid mixtures in Langmuir films. The density of the building blocks, size and shape of the resulting patterns can be controlled by tailoring the lateral surface

  15. Methemoglobinemia due to ingestion of N,N-dimethyl-p-toluidine, a component used in the fabrication of artificial fingernails.

    PubMed

    Potter, J L; Krill, C E; Neal, D; Kofron, W G

    1988-10-01

    An acute cyanotic episode due to methemoglobinemia occurred in a 16-month old girl following the ingestion of N,N-dimethyl-p-toluidine, a commercially available component used in the production of artificial fingernails. The amount of the parent compound ingested was about 6 mg/kg of body weight. Administration of methylene blue was effective in the reversal of the methemoglobinemia. In vitro studies suggest that the activity of the compound was probably due to its biochemical transformation to the toxic metabolite p-methylphenylhydroxylamine. We expand the list of aromatic amino or nitro compounds and their derivatives capable of producing methemoglobinemia and call attention to the hazard of their ingestion. PMID:3178002

  16. Femtosecond laser nanostructuring of titanium metal towards fabrication of low-reflective surfaces over broad wavelength range

    NASA Astrophysics Data System (ADS)

    Dar, Mudasir H.; Kuladeep, R.; Saikiran, V.; Narayana Rao, D.

    2016-05-01

    We investigated experimentally the formation of laser induced periodic surface structures (LIPSS) on titanium (Ti) metal upon irradiation with linearly polarized Ti:Sapphire femtosecond (fs) laser pulses of ∼110 fs pulse width and 800 nm wavelength in air and water environments. It is observed that initially formed random and sparsely distributed nano-roughness (nanoholes, nanoparticles and nanoprotrusions) gets periodically structured with increase in number of laser pulses. In air at lower fluence, we observed the formation of high spatial frequency-LIPSS (HSFL) oriented parallel to the laser polarization direction, whereas at higher fluence formation of low spatial frequency-LIPSS (LSFL) were observed that are oriented perpendicular to the incident laser polarization. In water two types of subwavelength structures were observed, one with spatial periodicity of ∼λ/15 and oriented parallel to laser polarization, while the other oriented perpendicular to laser polarization with feature size of λ/4. The optimal conditions for fabricating periodic sub-wavelength structures are determined by controlling the fluence and pulse number. The fs laser induced surface modifications were found to suppress the specular reflection of the Ti surface over a wide wavelength range of 250-2000 nm to a great extent.

  17. Low-cost flexible supercapacitors with high-energy density based on nanostructured MnO2 and Fe2O3 thin films directly fabricated onto stainless steel

    PubMed Central

    Gund, Girish S.; Dubal, Deepak P.; Chodankar, Nilesh R.; Cho, Jun Y.; Gomez-Romero, Pedro; Park, Chan; Lokhande, Chandrakant D.

    2015-01-01

    The facile and economical electrochemical and successive ionic layer adsorption and reaction (SILAR) methods have been employed in order to prepare manganese oxide (MnO2) and iron oxide (Fe2O3) thin films, respectively with the fine optimized nanostructures on highly flexible stainless steel sheet. The symmetric and asymmetric flexible-solid-state supercapacitors (FSS-SCs) of nanostructured (nanosheets for MnO2 and nanoparticles for Fe2O3) electrodes with Na2SO4/Carboxymethyl cellulose (CMC) gel as a separator and electrolyte were assembled. MnO2 as positive and negative electrodes were used to fabricate symmetric SC, while the asymmetric SC was assembled by employing MnO2 as positive and Fe2O3 as negative electrode. Furthermore, the electrochemical features of symmetric and asymmetric SCs are systematically investigated. The results verify that the fabricated symmetric and asymmetric FSS-SCs present excellent reversibility (within the voltage window of 0–1 V and 0–2 V, respectively) and good cycling stability (83 and 91%, respectively for 3000 of CV cycles). Additionally, the asymmetric SC shows maximum specific capacitance of 92 Fg−1, about 2-fold of higher energy density (41.8 Wh kg−1) than symmetric SC and excellent mechanical flexibility. Furthermore, the “real-life” demonstration of fabricated SCs to the panel of SUK confirms that asymmetric SC has 2-fold higher energy density compare to symmetric SC. PMID:26208144

  18. Low-cost flexible supercapacitors with high-energy density based on nanostructured MnO2 and Fe2O3 thin films directly fabricated onto stainless steel

    NASA Astrophysics Data System (ADS)

    Gund, Girish S.; Dubal, Deepak P.; Chodankar, Nilesh R.; Cho, Jun Y.; Gomez-Romero, Pedro; Park, Chan; Lokhande, Chandrakant D.

    2015-07-01

    The facile and economical electrochemical and successive ionic layer adsorption and reaction (SILAR) methods have been employed in order to prepare manganese oxide (MnO2) and iron oxide (Fe2O3) thin films, respectively with the fine optimized nanostructures on highly flexible stainless steel sheet. The symmetric and asymmetric flexible-solid-state supercapacitors (FSS-SCs) of nanostructured (nanosheets for MnO2 and nanoparticles for Fe2O3) electrodes with Na2SO4/Carboxymethyl cellulose (CMC) gel as a separator and electrolyte were assembled. MnO2 as positive and negative electrodes were used to fabricate symmetric SC, while the asymmetric SC was assembled by employing MnO2 as positive and Fe2O3 as negative electrode. Furthermore, the electrochemical features of symmetric and asymmetric SCs are systematically investigated. The results verify that the fabricated symmetric and asymmetric FSS-SCs present excellent reversibility (within the voltage window of 0-1 V and 0-2 V, respectively) and good cycling stability (83 and 91%, respectively for 3000 of CV cycles). Additionally, the asymmetric SC shows maximum specific capacitance of 92 Fg-1, about 2-fold of higher energy density (41.8 Wh kg-1) than symmetric SC and excellent mechanical flexibility. Furthermore, the “real-life” demonstration of fabricated SCs to the panel of SUK confirms that asymmetric SC has 2-fold higher energy density compare to symmetric SC.

  19. Low-cost flexible supercapacitors with high-energy density based on nanostructured MnO2 and Fe2O3 thin films directly fabricated onto stainless steel.

    PubMed

    Gund, Girish S; Dubal, Deepak P; Chodankar, Nilesh R; Cho, Jun Y; Gomez-Romero, Pedro; Park, Chan; Lokhande, Chandrakant D

    2015-01-01

    The facile and economical electrochemical and successive ionic layer adsorption and reaction (SILAR) methods have been employed in order to prepare manganese oxide (MnO2) and iron oxide (Fe2O3) thin films, respectively with the fine optimized nanostructures on highly flexible stainless steel sheet. The symmetric and asymmetric flexible-solid-state supercapacitors (FSS-SCs) of nanostructured (nanosheets for MnO2 and nanoparticles for Fe2O3) electrodes with Na2SO4/Carboxymethyl cellulose (CMC) gel as a separator and electrolyte were assembled. MnO2 as positive and negative electrodes were used to fabricate symmetric SC, while the asymmetric SC was assembled by employing MnO2 as positive and Fe2O3 as negative electrode. Furthermore, the electrochemical features of symmetric and asymmetric SCs are systematically investigated. The results verify that the fabricated symmetric and asymmetric FSS-SCs present excellent reversibility (within the voltage window of 0-1 V and 0-2 V, respectively) and good cycling stability (83 and 91%, respectively for 3000 of CV cycles). Additionally, the asymmetric SC shows maximum specific capacitance of 92 Fg(-1), about 2-fold of higher energy density (41.8 Wh kg(-1)) than symmetric SC and excellent mechanical flexibility. Furthermore, the "real-life" demonstration of fabricated SCs to the panel of SUK confirms that asymmetric SC has 2-fold higher energy density compare to symmetric SC. PMID:26208144

  20. DNA nanostructures interacting with lipid bilayer membranes.

    PubMed

    Langecker, Martin; Arnaut, Vera; List, Jonathan; Simmel, Friedrich C

    2014-06-17

    CONSPECTUS: DNA has been previously shown to be useful as a material for the fabrication of static nanoscale objects, and also for the realization of dynamic molecular devices and machines. In many cases, nucleic acid assemblies directly mimic biological structures, for example, cytoskeletal filaments, enzyme scaffolds, or molecular motors, and many of the applications envisioned for such structures involve the study or imitation of biological processes, and even the interaction with living cells and organisms. An essential feature of biological systems is their elaborate structural organization and compartmentalization, and this most often involves membranous structures that are formed by dynamic assemblies of lipid molecules. Imitation of or interaction with biological systems using the tools of DNA nanotechnology thus ultimately and necessarily also involves interactions with lipid membrane structures, and thus the creation of DNA-lipid hybrid assemblies. Due to their differing chemical nature, however, highly charged nucleic acids and amphiphilic lipids do not seem the best match for the construction of such systems, and in fact they are rarely found in nature. In recent years, however, a large variety of lipid-interacting DNA conjugates were developed, which are now increasingly being applied also for the realization of DNA nanostructures interacting with lipid bilayer membranes. In this Account, we will present the current state of this emerging class of nanosystems. After a brief overview of the basic biophysical and biochemical properties of lipids and lipid bilayer membranes, we will discuss how DNA molecules can interact with lipid membranes through electrostatic interactions or via covalent modification with hydrophobic moieties. We will then show how such DNA-lipid interactions have been utilized for the realization of DNA nanostructures attached to or embedded within lipid bilayer membranes. Under certain conditions, DNA nanostructures remain mobile on

  1. Design, fabrication and evaluation of two-dimensional to three-dimensional nanostructured ceramic/polymer composites for orthopedic regeneration and controlled drug delivery

    NASA Astrophysics Data System (ADS)

    Liu, Huinan

    Desirable cytocompatibility properties of nano-sized ceramics were combined with the tunable degradability and deformability of a select polymer (poly-lactide-co-glycolide, or PLGA) to optimize biological and mechanical properties for orthopedic tissue regeneration. Nanophase ceramics mimic the size scale of constituent components of natural bone and enhance the adsorption of proteins that mediate bone cell adhesion. Results have shown significantly promoted osteoblast (bone-forming cell) adhesion and long-term functions (alkaline phosphatase activity and calcium deposition) on nanophase ceramics compared to conventional (micron-scale) ceramics. Therefore, nano-titania particles were first dispersed in a model polymer (PLGA) matrix using sonication to imitate the nano-sized surface features and distribution of nano-ceramics in/on bone. Surface characteristics of the composites (such as topography, surface area and surface roughness) were studied. Importantly, results showed that osteoblast adhesion was the greatest when surface roughness values of the composites were closer to that of natural bone; this was mediated by controlling the dispersion of titania in PLGA. Moreover, this study demonstrated that the dispersion of nanophase titania in PLGA decreased the harmful acidic pH changes of PLGA as it degrades. From the perspective of mechanical properties, compared to agglomerated nano-titania in PLGA, well-dispersed nanophase titania in PLGA improved the tensile and compressive moduli and strength of these composites. In order to mimic the hierarchical structure of bone, a novel aerosol-based 3D printing technique was used to further fabricate nanostructured 3D ceramic/polymer composites. Osteoblast interactions with these 3D scaffolds provided evidence of an even further promoted bone cell infiltration into such 3D structures. Lastly, nanocomposites were used as novel drug delivery systems to promote bone growth. Specifically, a bone morphogenetic protein (BMP-7

  2. Nanostructure devices and fabrication method

    NASA Technical Reports Server (NTRS)

    Stevens, Ramsey M. (Inventor)

    2009-01-01

    An ion flux is directed to a carbon nanotube to permanently shape, straighten and/or bend the carbon nanotube into a desired configuration. Such carbon nanotubes have many properties that make them ideal as probes for Scanning Probe Microscopy and many other applications.

  3. MgCO3·3H2O and MgO complex nanostructures: controllable biomimetic fabrication and physical chemical properties.

    PubMed

    Wu, Xiaoming; Cao, Huaqiang; Yin, Gui; Yin, Jiefu; Lu, Yuexiang; Li, Baojun

    2011-03-21

    In this paper, we report a method of biomimetic synthesis of MgCO(3)·3H(2)O and MgO Viburnum opulus-like complex nanostructures with superhydrophobicity and adsorption properties. The MgCO(3)·3H(2)O complex nanostructures can be obtained by changing experimental parameters, including concentrations of reactants (dextran and MgCl(2)), molar ratios of reactants, and reaction time. The phase structure of as-synthesized samples was characterized by X-ray diffraction (XRD). The morphology and structure are studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) spectroscopy. The MgCO(3)·3H(2)O complex nanostructures exhibited superhydrophobicity, due to their unique superstructures, and was proved by the contact angle (CA) measurement. We also show that a simple calcination of these unusually shaped MgCO(3)·3H(2)O results in spontaneous formation of MgO complex nanostructures while the unique shape can be maintained, and the as-synthesized MgO nanostructures show excellent adsorption property. These unique structures and properties will open up a wide range of potential applications in material and environmental protection. PMID:21170433

  4. Hybrid lipid-based nanostructures

    NASA Astrophysics Data System (ADS)

    Dayani, Yasaman

    Biological membranes serve several important roles, such as structural support of cells and organelles, regulation of ionic and molecular transport, barriers to non-mediated transport, contact between cells within tissues, and accommodation of membrane proteins. Membrane proteins and other vital biomolecules incorporated into the membrane need a lipid membrane to function. Due to importance of lipid bilayers and their vital function in governing many processes in the cell, the development of various models as artificial lipid membranes that can mimic cell membranes has become a subject of great interest. Using different models of artificial lipid membranes, such as liposomes, planar lipid bilayers and supported or tethered lipid bilayers, we are able to study many biophysical processes in biological membranes. The ability of different molecules to interact with and change the structure of lipid membranes can be also investigated in artificial lipid membranes. An important application of lipid bilayer-containing interfaces is characterization of novel membrane proteins for high throughput drug screening studies to investigate receptor-drug interactions and develop biosensor systems. Membrane proteins need a lipid bilayer environment to preserve their stability and functionality. Fabrication of materials that can interact with biomolecules like proteins necessitates the use of lipid bilayers as a mimic of cell membranes. The objective of this research is to develop novel hybrid lipid-based nanostructures mimicking biological membranes. Toward this aim, two hybrid biocompatible structures are introduced: lipid bilayer-coated multi-walled carbon nanotubes (MWCNTs) and hydrogel-anchored liposomes with double-stranded DNA anchors. These structures have potential applications in biosensing, drug targeting, drug delivery, and biophysical studies of cell membranes. In the first developed nanostructure, lipid molecules are covalently attached to the surfaces of MWCNTs, and

  5. Solvent directed fabrication of Bi{sub 2}WO{sub 6} nanostructures with different morphologies: Synthesis and their shape-dependent photocatalytic properties

    SciTech Connect

    Mi, Yuwei; Zeng, Suyuan; Li, Lei; Zhang, Qingfu; Wang, Suna; Liu, Caihua; Sun, Dezhi

    2012-09-15

    Graphical abstract: The morphologies of the Bi{sub 2}WO{sub 6} nanostructures can be easily tuned by altering the solvent composition during the reaction, which will yield flower-like, pancake-like and tubular nanostructures, respectively. Highlights: ► The morphologies of Bi{sub 2}WO{sub 6} can be controlled by tuning the solvent composition. ► The effects of solvent on the morphologies of Bi{sub 2}WO{sub 6} were carefully investigated. ► The growth mechanisms for the as-prepared samples were investigated. ► The morphologies of the samples greatly affect their photocatalytic activities. -- Abstract: In this work, Bi{sub 2}WO{sub 6} with complex morphologies, namely, flower-like, pancake-like, and tubular shapes have been controllably synthesized by a facile solvothermal process. The as-obtained samples are systematically investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). The effects of solvents on the morphologies of Bi{sub 2}WO{sub 6} nanostructures are systematically investigated. According to the time-dependent experiments, a two-step growth mode basing on Ostwald ripening process and self-assembly has been proposed for the formation of the flower-like and pancake-like Bi{sub 2}WO{sub 6} nanostructures. The photocatalytic properties of Bi{sub 2}WO{sub 6} nanostructures are strongly dependent on their shapes, sizes, and structures for the degradation of rhodamine B (RhB) under visible-light irradiation. The deduced reasons for the differences in the photocatalytic activities of these Bi{sub 2}WO{sub 6} nanostructures are further discussed.

  6. Nanostructured Biomaterials for Regeneration**

    PubMed Central

    Wei, Guobao; Ma, Peter X.

    2009-01-01

    Biomaterials play a pivotal role in regenerative medicine, which aims to regenerate and replace lost/dysfunctional tissues or organs. Biomaterials (scaffolds) serve as temporary 3D substrates to guide neo tissue formation and organization. It is often beneficial for a scaffolding material to mimic the characteristics of extracellular matrix (ECM) at the nanometer scale and to induce certain natural developmental or/and wound healing processes for tissue regeneration applications. This article reviews the fabrication and modification technologies for nanofibrous, nanocomposite, and nanostructured drug-delivering scaffolds. ECM-mimicking nanostructured biomaterials have been shown to actively regulate cellular responses including attachment, proliferation, differentiation and matrix deposition. Nano-scaled drug delivery systems can be successfully incorporated into a porous 3D scaffold to enhance the tissue regeneration capacity. In conclusion, nano-structured biomateials are a very exciting and rapidly expanding research area, and are providing new enabling technologies for regenerative medicine. PMID:19946357

  7. Emerging double helical nanostructures

    NASA Astrophysics Data System (ADS)

    Zhao, Meng-Qiang; Zhang, Qiang; Tian, Gui-Li; Wei, Fei

    2014-07-01

    As one of the most important and land-mark structures found in nature, a double helix consists of two congruent single helices with the same axis or a translation along the axis. This double helical structure renders the deoxyribonucleic acid (DNA) the crucial biomolecule in evolution and metabolism. DNA-like double helical nanostructures are probably the most fantastic yet ubiquitous geometry at the nanoscale level, which are expected to exhibit exceptional and even rather different properties due to the unique organization of the two single helices and their synergistic effect. The organization of nanomaterials into double helical structures is an emerging hot topic for nanomaterials science due to their promising exceptional unique properties and applications. This review focuses on the state-of-the-art research progress for the fabrication of double-helical nanostructures based on `bottom-up' and `top-down' strategies. The relevant nanoscale, mesoscale, and macroscopic scale fabrication methods, as well as the properties of the double helical nanostructures are included. Critical perspectives are devoted to the synthesis principles and potential applications in this emerging research area. A multidisciplinary approach from the scope of nanoscience, physics, chemistry, materials, engineering, and other application areas is still required to the well-controlled and large-scale synthesis, mechanism, property, and application exploration of double helical nanostructures.

  8. A Strategy for Fabricating Porous PdNi@Pt Core-shell Nanostructures and Their Enhanced Activity and Durability for the Methanol Electrooxidation

    NASA Astrophysics Data System (ADS)

    Liu, Xinyu; Xu, Guangrui; Chen, Yu; Lu, Tianhong; Tang, Yawen; Xing, Wei

    2015-01-01

    Three-dimensionally (3D) porous morphology of nanostructures can effectively improve their electrocatalytic activity and durability for various electrochemical reactions owing to big surface area and interconnected structure. Cyanogel, a jelly-like inorganic polymer, can be used to synthesize various three-dimensionally (3D) porous alloy nanomaterials owing to its double-metal property and particular 3D backbone. Here, 3D porous PdNi@Pt core-shell nanostructures (CSNSs) are facilely synthesized by first preparing the Pd-Ni alloy networks (Pd-Ni ANWs) core via cyanogel-reduction method followed by a galvanic displacement reaction to generate the Pt-rich shell. The as-synthesized PdNi@Pt CSNSs exhibit a much improved catalytic activity and durability for the methanol oxidation reaction (MOR) in the acidic media compared to the commercial used Pt black because of their specific structural characteristics. The facile and mild method described herein is highly attractive for the synthisis of 3D porous core-shell nanostructures.

  9. Cobalt(II) phthalocyanine-sensitized hollow Fe3O4@SiO2@TiO2 hierarchical nanostructures: Fabrication and enhanced photocatalytic properties

    NASA Astrophysics Data System (ADS)

    Wu, Song-Hai; Wu, Jing-Long; Jia, Shao-Yi; Chang, Qiao-Wan; Ren, Hai-Tao; Liu, Yong

    2013-12-01

    Cobalt(II) phthalocyanine-sensitized hollow Fe3O4@SiO2@TiO2 hierarchical nanostructures had been successfully obtained by combination of solvothermal processing and dipping processing. The as-obtained products were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), UV-vis diffuse reflectance (DR) and vibrating sample magnetometer (VSM). The results revealed that the cobalt(II) phthalocyanine was successfully grown on the primary Fe3O4@SiO2@TiO2 nanostructures (Fe3O4@SiO2@TiO2@CoPcS). The hollow Fe3O4@SiO2@TiO2@CoPcS hierarchical nanostructure showed excellent photocatalytic efficiency for the degradation of methylene blue (MB) under UV-vis and visible light irradiation. More importantly, the photocatalyst could be effectively separated for reuse by simply applying an external magnetic field. A possible mechanism for the visible photocatalysis with the Fe3O4@SiO2@TiO2@CoPcS heterostructures was suggested.

  10. Spatially-Interactive Biomolecular Networks Organized by Nucleic Acid Nanostructures

    PubMed Central

    Fu, Jinglin; Liu, Minghui; Liu, Yan; Yan, Hao

    2013-01-01

    Conspectus Living systems have evolved a variety of nanostructures to control the molecular interactions that mediate many functions including the recognition of targets by receptors, the binding of enzymes to substrates, and the regulation of enzymatic activity. Mimicking these structures outside of the cell requires methods that offer nanoscale control over the organization of individual network components. Advances in DNA nanotechnology have enabled the design and fabrication of sophisticated one-, two- and three-dimensional (1D, 2D and 3D) nanostructures that utilize spontaneous and sequence specific DNA hybridization. Compared to other self-assembling biopolymers, DNA nanostructures offer predictable and programmable interactions, and surface features to which other nanoparticles and bio-molecules can be precisely positioned. The ability to control the spatial arrangement of the components while constructing highly-organized networks will lead to various applications of these systems. For example, DNA nanoarrays with surface displays of molecular probes can sense noncovalent hybridization interactions with DNA, RNA, and proteins and covalent chemical reactions. DNA nanostructures can also align external molecules into well-defined arrays, which may improve the resolution of many structural determination methods, such as X-ray diffraction, cryo-EM, NMR, and super-resolution fluorescence. Moreover, by constraining target entities to specific conformations, self-assembled DNA nanostructures can serve as molecular rulers to evaluate conformation-dependent activities. This Account describes the most recent advances in the DNA nanostructure directed assembly of biomolecular networks and explores the possibility of applying this technology to other fields of study. Recently, several reports have demonstrated the DNA nanostructure directed assembly of spatially-interactive biomolecular networks. For example, researchers have constructed synthetic multi-enzyme cascades

  11. Oxidation of ethyl acetate by a high performance nanostructure (Ni, Mn)-Ag/ZSM-5 bimetallic catalysts and development of an artificial neural networks predictive modeling.

    PubMed

    Jodaei, Azadeh; Salari, Darush; Niaei, Ali; Khatamian, Masumeh; Hosseini, Seyed Ali

    2011-01-01

    The catalytic oxidation of ethyl acetate in low concentration was investigated over mono-metallic Ag/ZSM5 and bimetallic (Ni, Mn)-Ag/ZSM-5 catalysts. Catalytic studies were carried out in a catalytic fixed bed reactor under atmospheric pressure. The sequence of catalytic activity was as follows: Ni-Ag-ZSM-5 > Mn-Ag-ZSM-5 > Ag-ZSM-5 > H-ZSM-5. The catalysts were characterized by ICP-AES, X-ray diffraction (XRD), low temperature nitrogen adsorption, NH(3)-TPD, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and diffuse reflectance UV-vis spectra (UV-vis). An artificial neural networks (ANN) model was developed to predict the performance of catalytic oxidation process over bimetallic Ni-Ag/ZSM-5 catalyst based on experimental data. For this purpose the standard feed forward back propagation algorithm was employed to train the model by using laboratory experimental data. A good agreement was resulted between experimental results and those obtained by ANN. Following order for variables effects on conversion yield of ethyl acetate was predicted by ANN model: reaction temperature (32.99%) > Ag loading (27.38%) > initial ethyl acetate concentration (23.58%) > Ni loading (16.05%). PMID:21104495

  12. Surface engineering of artificial heart valve disks using nanostructured thin films deposited by chemical vapour deposition and sol-gel methods.

    PubMed

    Jackson, M J; Robinson, G M; Ali, N; Kousar, Y; Mei, S; Gracio, J; Taylor, H; Ahmed, W

    2006-01-01

    Pyrolytic carbon (PyC) is widely used in manufacturing commercial artificial heart valve disks (HVD). Although PyC is commonly used in HVD, it is not the best material for this application since its blood compatibility is not ideal for prolonged clinical use. As a result thrombosis often occurs and the patients are required to take anti-coagulation drugs on a regular basis in order to minimize the formation of thrombosis. However, anti-coagulation therapy gives rise to some detrimental side effects in patients. Therefore, it is extremely urgent that newer and more technically advanced materials with better surface and bulk properties are developed. In this paper, we report the mechanical properties of PyC-HVD, i.e. strength, wear resistance and coefficient of friction. The strength of the material was assessed using Brinell indentation tests. Furthermore, wear resistance and coefficient of friction values were obtained from pin-on-disk testing. The micro-structural properties of PyC were characterized using XRD, Raman spectroscopy and SEM analysis. Also in this paper we report the preparation of freestanding nanocrystalline diamond films (FSND) using the time-modulated chemical vapour deposition (TMCVD) process. Furthermore, the sol-gel technique was used to uniformly coat PyC-HVD with dense, nanocrystalline-titanium oxide (nc-TiO2) coatings. The as-grown nc-TiO2 coatings were characterized for microstructure using SEM and XRD analysis. PMID:16980288

  13. Processing of Nanostructured Devices Using Microfabrication Techniques

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W (Inventor); Xu, Jennifer C (Inventor); Evans, Laura J (Inventor); Kulis, Michael H (Inventor); Berger, Gordon M (Inventor); Vander Wal, Randall L (Inventor)

    2014-01-01

    Systems and methods that incorporate nanostructures into microdevices are discussed herein. These systems and methods can allow for standard microfabrication techniques to be extended to the field of nanotechnology. Sensors incorporating nanostructures can be fabricated as described herein, and can be used to reliably detect a range of gases with high response.

  14. Biomimicry of multifunctional nanostructures in the neck feathers of mallard (Anas platyrhynchos L.) drakes

    NASA Astrophysics Data System (ADS)

    Khudiyev, Tural; Dogan, Tamer; Bayindir, Mehmet

    2014-04-01

    Biological systems serve as fundamental sources of inspiration for the development of artificially colored devices, and their investigation provides a great number of photonic design opportunities. While several successful biomimetic designs have been detailed in the literature, conventional fabrication techniques nonetheless remain inferior to their natural counterparts in complexity, ease of production and material economy. Here, we investigate the iridescent neck feathers of Anas platyrhynchos drakes, show that they feature an unusual arrangement of two-dimensional (2D) photonic crystals and further exhibit a superhydrophobic surface, and mimic this multifunctional structure using a nanostructure composite fabricated by a recently developed top-down iterative size reduction method, which avoids the above-mentioned fabrication challenges, provides macroscale control and enhances hydrophobicity through the surface structure. Our 2D solid core photonic crystal fibres strongly resemble drake neck plumage in structure and fully polymeric material composition, and can be produced in wide array of colors by minor alterations during the size reduction process.

  15. Large-scale low temperature fabrication of SnO2 hollow/nanoporous nanostructures: the template-engaged replacement reaction mechanism and high-rate lithium storage.

    PubMed

    Ding, Yuan-Li; Wen, Yuren; van Aken, Peter A; Maier, Joachim; Yu, Yan

    2014-10-01

    The morphology-controlled synthesis of SnO2 hollow/nanoporous nanostructures (nanotubes, urchin-like morphologies and nanospheres) was achieved via a template-engaged replacement reaction at a mild temperature (lower than 80 °C). The formation mechanism of hollow interior and nanoporous walls for the obtained SnO2 nanostructures (SnO2 nanotubes were used as an example) was investigated based on TEM and HRTEM observations during different reaction stages. It is found that bridge voids firstly form at the MnO2/SnO2 interface, followed by the inward development of voids before the MnO2 core is completely consumed. Two types of short-circuited galvanic cells, MnO2/Mn(2+)∣SnO2/Sn(2+) and concentration cell-SnO2/Sn(2+) (interior)∣SnO2/Sn(2+) (exterior), are probably responsible for the formation of SnO2 nanotubes and outward growth of SnO2 along MnO2. Moreover, the calculation result of the outer diameter of SnO2 nanotubes is in good agreement with the observation results by SEM and TEM. When evaluated as anodes for lithium ion batteries (LIBs), the three SnO2 nanostructures exhibit superior rate capability and cycling performance. Especially, SnO2 nanotubes present the best rate capability: specific capacities of above 800 mA h g(-1) at 200 mA g(-1) and about 500 mA h g(-1) at 4000 mA g(-1) were achieved, respectively. Importantly, the 1D morphology of SnO2 nanotubes can be well preserved after prolonged cycling at a relatively high current density, indicating good structural stability of the resulting nanotubes during the Li(+) insertion/extraction process. These results indicate that the obtained SnO2 hollow/nanoporous nanostructures would be promising anode materials for next-generation LIBs. PMID:25148613

  16. Large-scale low temperature fabrication of SnO2 hollow/nanoporous nanostructures: the template-engaged replacement reaction mechanism and high-rate lithium storage

    NASA Astrophysics Data System (ADS)

    Ding, Yuan-Li; Wen, Yuren; van Aken, Peter A.; Maier, Joachim; Yu, Yan

    2014-09-01

    The morphology-controlled synthesis of SnO2 hollow/nanoporous nanostructures (nanotubes, urchin-like morphologies and nanospheres) was achieved via a template-engaged replacement reaction at a mild temperature (lower than 80 °C). The formation mechanism of hollow interior and nanoporous walls for the obtained SnO2 nanostructures (SnO2 nanotubes were used as an example) was investigated based on TEM and HRTEM observations during different reaction stages. It is found that bridge voids firstly form at the MnO2/SnO2 interface, followed by the inward development of voids before the MnO2 core is completely consumed. Two types of short-circuited galvanic cells, MnO2/Mn2+|SnO2/Sn2+ and concentration cell-SnO2/Sn2+ (interior)|SnO2/Sn2+ (exterior), are probably responsible for the formation of SnO2 nanotubes and outward growth of SnO2 along MnO2. Moreover, the calculation result of the outer diameter of SnO2 nanotubes is in good agreement with the observation results by SEM and TEM. When evaluated as anodes for lithium ion batteries (LIBs), the three SnO2 nanostructures exhibit superior rate capability and cycling performance. Especially, SnO2 nanotubes present the best rate capability: specific capacities of above 800 mA h g-1 at 200 mA g-1 and about 500 mA h g-1 at 4000 mA g-1 were achieved, respectively. Importantly, the 1D morphology of SnO2 nanotubes can be well preserved after prolonged cycling at a relatively high current density, indicating good structural stability of the resulting nanotubes during the Li+ insertion/extraction process. These results indicate that the obtained SnO2 hollow/nanoporous nanostructures would be promising anode materials for next-generation LIBs.The morphology-controlled synthesis of SnO2 hollow/nanoporous nanostructures (nanotubes, urchin-like morphologies and nanospheres) was achieved via a template-engaged replacement reaction at a mild temperature (lower than 80 °C). The formation mechanism of hollow interior and nanoporous walls

  17. Vortex ice in nanostructured superconductors

    SciTech Connect

    Reichhardt, Charles; Reichhardt, Cynthia J; Libal, Andras J

    2008-01-01

    We demonstrate using numerical simulations of nanostructured superconductors that it is possible to realize vortex ice states that are analogous to square and kagome ice. The system can be brought into a state that obeys either global or local ice rules by applying an external current according to an annealing protocol. We explore the breakdown of the ice rules due to disorder in the nanostructure array and show that in square ice, topological defects appear along grain boundaries, while in kagome ice, individual defects appear. We argue that the vortex system offers significant advantages over other artificial ice systems.

  18. Precise replication of antireflective nanostructures from biotemplates

    NASA Astrophysics Data System (ADS)

    Gao, Hongjun; Liu, Zhongfan; Zhang, Jin; Zhang, Guoming; Xie, Guoyong

    2007-03-01

    The authors report herein a new type of nanonipple structures on the cicada's eye and the direct structural replication of the complex micro- and nanostructures for potential functional emulation. A two-step direct molding process is developed to replicate these natural micro- and nanostructures using epoxy resin with high fidelity, which demonstrates a general way of fabricating functional nanostructures by direct replication of natural biotemplates via a suitable physicochemical process. Measurements of spectral reflectance showed that this kind of replicated nanostructure has remarkable antireflective property, suggestive of its potential applications to optical devices.

  19. Processing Nanostructured Sensors Using Microfabrication Techniques

    NASA Technical Reports Server (NTRS)

    Hunter, Gary W.; VanderWal, Randall L.; Evans, Laura J.; Xu, Jennifer C.

    2010-01-01

    Standard microfabrication techniques can be implemented and scaled to help assemble nanoscale microsensors. Currently nanostructures are often deposited onto materials primarily by adding them to a solution, then applying the solution in a thin film. This results in random placement of the nanostructures with no controlled order, and no way to accurately reproduce the placement. This method changes the means by which microsensors with nanostructures are fabricated. The fundamental advantage to this approach is that it enables standard microfabrication techniques to be applied in the repeated manufacture of nanostructured sensors on a microplatform.

  20. Nanostructures created by interfered femtosecond laser

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Chang, Yun-Ching; Yao, Jimmy; Luo, Claire; Yin, Shizhuo; Ruffin, Paul; Brantley, Christina; Edwards, Eugene

    2011-10-01

    The method by applying the interfered femtosecond laser to create nanostructured copper (Cu) surface has been studied. The nanostructure created by direct laser irradiation is also realized for comparison. Results show that more uniform and finer nanostructures with sphere shape and feature size around 100 nm can be induced by the interfered laser illumination comparing with the direct laser illumination. This offers an alternative fabrication approach that the feature size and the shape of the laser induced metallic nanostructures can be highly controlled, which can extremely improve its performance in related application such as the colorized metal, catalyst, SERS substrate, and etc.

  1. Bioinspired micro-/nanostructure fibers with a water collecting property

    NASA Astrophysics Data System (ADS)

    Chen, Yuan; Zheng, Yongmei

    2014-06-01

    We review the recent research on structure-induced water collecting properties of spider silk and bioinspired fibers. Since the capture silks of cribellate spiders have a unique wet-rebuilt structure with spindle-knots and joints for directional water collection, we were inspired to fabricate a series of artificial gradient micro-/nanostructure fibers. These fibers display excellent functions, such as driving tiny water drops in certain directions, water capturing, multi-gradient cooperation effect, and wet-response to environmental humidity. This review is helpful to the design of novel smart functional materials that can be extended to develop devices or systems for water collection, sensors, fluid-control, filters and others.

  2. Graphene-and-Copper Artificial Nacre Fabricated by a Preform Impregnation Process: Bioinspired Strategy for Strengthening-Toughening of Metal Matrix Composite.

    PubMed

    Xiong, Ding-Bang; Cao, Mu; Guo, Qiang; Tan, Zhanqiu; Fan, Genlian; Li, Zhiqiang; Zhang, Di

    2015-07-28

    Metals can be strengthened by adding hard reinforcements, but such strategy usually compromises ductility and toughness. Natural nacre consists of hard and soft phases organized in a regular "brick-and-mortar" structure and exhibits a superior combination of mechanical strength and toughness, which is an attractive model for strengthening and toughening artificial composites, but such bioinspired metal matrix composite has yet to be made. Here we prepared nacre-like reduced graphene oxide (RGrO) reinforced Cu matrix composite based on a preform impregnation process, by which two-dimensional RGrO was used as "brick" and inserted into "□-and-mortar" ordered porous Cu preform (the symbol "□" means the absence of "brick"), followed by compacting. This process realized uniform dispersion and alignment of RGrO in Cu matrix simultaneously. The RGrO-and-Cu artificial nacres exhibited simultaneous enhancement on yield strength and ductility as well as increased modulus, attributed to RGrO strengthening, effective crack deflection and a possible combined failure mode of RGrO. The artificial nacres also showed significantly higher strengthening efficiency than other conventional Cu matrix composites, which might be related to the alignment of RGrO. PMID:26083407

  3. Antibacterial Au nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It

  4. Fabrication of hierarchical Fe3O4@SiO2@P(4VP-DVB)@Au nanostructures and their enhanced catalytic properties.

    PubMed

    Guo, Wanchun; Wang, Qian; Luan, Yi; Wang, Ge; Dong, Wenjun; Yu, Jie

    2015-03-01

    Hierarchical Fe3O4@SiO2@P(4VP-DVB)@Au nanostructures were prepared in which the slightly cross-linked, thin poly(4-vinylpyridine-co-divinylbenzene) (P(4VP-DVB)) shells were constructed onto Fe3O4@SiO2 nanospheres, followed by in situ embedding of gold nanocrystals homogeneously into the P4VP chains. These slightly cross-linked chains, easily swollen by the reactants, make the gold nanocrystals accessible to the reactants, and the thin shell (about 15 nm) reduces the diffusion distance of the reactants to the active gold nanocrystals (about 5 nm), thereby enhancing their catalytic activity and utility. At the same time, confinement of gold nanocrystals within the P4VP shells prevents their migration and coagulation during catalytic transformations. Hence the nanocomposites exhibit high activity (up to 4369.5 h(-1) of turnover frequency (TOF)) and controllable magnetic recyclability without any significant loss of gold species after ten runs of catalysis in the reduction of 4-nitrophenol. PMID:25585563

  5. Cross-beam pulsed laser fabrication of Free-Standing Nanostructured Carbon Nanotubes-Pt-Ceria Anode with unprecedented electroactivity and durability for ethanol oxidation

    NASA Astrophysics Data System (ADS)

    Wang, Youling; Tabet-Aoul, Amel; Gougis, Maxime; Mohamedi, Mohamed

    2015-01-01

    Owing to its inherent properties such as great capacity to store and release oxygen, lattice oxygen that has a key role in removing the CO poisoning effect, non-toxicity, abundance, low cost and low temperature processing, CeO2 is emerging as a unique class of electrode material for low temperature polymer electrolyte fuel cells such as direct ethanol fuel cells (DEFCs). However, the maximal exploitation of its functional properties is strictly reliant on the availability of optimized synthesis routes that allow tailor-designing, architecturing and manipulation of CeO2 in a precise manner when it is combined with other functional materials. Here we use the cross-beam pulsed laser deposition (CBPLD) technique to synthesize free-standing (binderless) Pt-CeO2 nanostructured thin films onto carbon nanotubes as anodes for ethanol oxidation reaction. Further significance of this work is that it establishes the importance in the design of the catalyst layer architecture. Indeed, we demonstrate here that when CeO2 material is beneath or when it is mixed with Pt, the interactions between Pt with CeO2 are not similar leading inevitably to different electrocatalytic performances. Given proper tailoring synthesis conditions, CBPLD-developed Pt-CeO2 thin films are remarkably stable and provide electrochemical performance much greater than the layer onto layer CeO2/Pt architecture.

  6. Influences of laser remelting on microstructure of nanostructured Al 2O 3-13 wt.% TiO 2 coatings fabricated by plasma spraying

    NASA Astrophysics Data System (ADS)

    Wang, Dongsheng; Tian, Zongjun; Shen, Lida; Liu, Zhidong; Huang, Yinhui

    2009-02-01

    The effects of laser remelting on microstructure of nanostructured Al 2O 3-13 wt.% TiO 2 ceramic coatings prepared by plasma spraying with agglomerated powders were studied. The microstructure of the feedstock, as-sprayed and laser-remelted coatings were investigated by using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffractometry (XRD). The results indicate that the plasma-sprayed ceramic coating consists of both fully melted regions and partially melted regions. The totally ceramic coating, especially the fully melted regions, has a typical plasma-sprayed lamellar-like structure as the conventional coating, and has some pores. According to the difference of microstructures, the partially melted regions can be divided into liquid-phase sintered regions (a three-dimensional net or skeleton-like structure: Al 2O 3-rich submicron particles embedded in the TiO 2-rich matrix) and solid-phase sintered regions (remained nanoparticles). The lamellar defect of the as-sprayed coating is erased, and the compactness of the coating is improved significantly after laser remelting. The laser-remelted region composed of fine equiaxed grains, which are different from the conventional column-like crystals along the direction of the heat current. Due to the rapid solidification of laser remelting process, there are still some nanoparticles in the remelted region because of an insufficient time for grains growth.

  7. Testing gold nanostructures fabricated by hole-mask colloidal lithography as potential substrates for SERS sensors: sensitivity, signal variability, and the aspect of adsorbate deposition.

    PubMed

    Peksa, Vlastimil; Lebrušková, Petra; Šípová, Hana; Štěpánek, Josef; Bok, Jiří; Homola, Jiří; Procházka, Marek

    2016-07-20

    Gold nanoplasmonic substrates with high sensitivity and spectral reproducibility are key components of molecular sensors based on surface-enhanced Raman scattering (SERS). In this work, we used a confocal Raman microscope and several types of gold nanostructures (arrays of nanodiscs, nanocones and nanodisc dimers) prepared by hole-mask colloidal lithography (HCL) to determine the sources of variability in SERS measurements. We demonstrate that significant variations in the SERS signal can originate from the method of deposition of analyte molecules onto a SERS substrate. While the method based on incubation of SERS substrates in a solution containing the analyte yields a SERS signal with low variability, the droplet deposition method produces a SERS signal with rather high variability. Variability of the SERS signal of a single nanoparticle was determined from the statistical analysis of the SERS signal in short-range Raman maps recorded using different sized laser spots produced by means of different objectives. We show that the number of nanoparticles located within the laser spot can be a source of substantial SERS signal variability, especially for high-magnification objectives. We demonstrate that SERS substrates prepared by HCL exhibit high SERS enhancement and excellent homogeneity (about 20% relative standard deviation from short-range maps). The nanocone arrays are shown to provide the highest SERS enhancement, the lowest relative level of fluorescence background, and also slightly better homogeneity when compared with arrays of nanodisc dimers or single nanodiscs. PMID:27381363

  8. Understanding the role of ‘path’ for sacrificial substance migration during the fabrication of hollow nanostructures in PtPdCu system

    NASA Astrophysics Data System (ADS)

    Gong, Hongyu; Li, Fan; Yang, Zhanbing; Wang, Yizhi

    2015-08-01

    PtPdCu nanoparticles (NPs) were etched by acid to prepare hollow nanostructures (HNSs). A hypothesis ‘path’ was given. The rate of Cu migration is different in amorphous and in crystalline structures, and is usually faster in amorphous structures. The fast mass transport part looked like a road for Cu migration, and it was named the ‘path’. With time passing, phase transfer occurs; the ‘path’ may shrink until it is closed. These changes of the status of the ‘path’ would affect the results of the Kirkendall effect, separate voids or big holes inside particles. This could indicate that only a 10 K temperature difference in the synthesis results in the final productivity of the HNSs, and even the morphologies, being different during the same leaching process. High resolution electron microscopy images obtained during the leaching process gave evidence of a glass-like region and a crystal region coexisting, which was evidence of the ‘path’ formed.

  9. The Development of Metal Oxide Chemical Sensing Nanostructures

    NASA Technical Reports Server (NTRS)

    Hunter, G. W.; VanderWal,R. L.; Xu, J. C.; Evans, L. J.; Berger, G. M.; Kulis, M. J.

    2008-01-01

    This paper discusses sensor development based on metal oxide nanostructures and microsystems technology. While nanostructures such as nanowires show significant potential as enabling materials for chemical sensors, a number of significant technical challenges remain. This paper discusses development to address each of these technical barriers: 1) Improved contact and integration of the nanostructured materials with microsystems in a sensor structure; 2) Control of nanostructure crystallinity to allow control of the detection mechanism; and 3) Widening the range of gases that can be detected by fabricating multiple nanostructured materials. A sensor structure composed of three nanostructured oxides aligned on a single microsensor has been fabricated and tested. Results of this testing are discussed and future development approaches are suggested. It is concluded that while this work lays the foundation for further development, these are the beginning steps towards realization of repeatable, controlled sensor systems using oxide based nanostructures.

  10. Self-assembled DNA nanostructures and DNA-templated silver nanowires

    NASA Astrophysics Data System (ADS)

    Park, Sung Ha

    DNA-based nanotechnology has been attractive as a novel assembly method for fabricating nanostructures for the last two decades. Artificially designed, self-assembled DNA nanostructures have been reported with various geometrical structures and functionalities: one- and two-dimensional periodically patterned structures, three-dimensional polyhedra, nanomechanical devices, molecular computers, and organization of other functionalized molecules. This thesis describes self-assembled DNA nanostructures and DNA-templated metallic nanowires. One- and two-dimensional periodically patterned superstructures, such as filaments, lattices, nanoribbons, nanotracks, and nanogrids, utilizing newly conceived two distinct DNA motifs---three helix bundles, and the cross-tiles as well as synthetic double-stranded DNA molecules---will be discussed with unique design schemes and characteristics. DNA complexes have been visualized by high-resolution tapping mode atomic force microscopy under buffer. Their dimensions are shown to be in excellent agreement with designed structures. We have also presented fabrication of size-controllable, fully addressable, and precisely programmable DNA-based nanomatrices, consisting of two different cross-tiles using a novel stepwise assembly technique. Especially in design and construction of functionalized electronic nanodevices, properly fabricated DNA lattices can serve as a precisely controllable and programmable scaffold for organizing functionalized nanomaterials. DNA-templated metallic nanowires are an example demonstration of DNA molecules' scaffold capability and have been considered an interesting research subject for the last decade. Until recently, mostly native lambda-DNA molecules have been used as template for fabricating various metallic nanowires, such as silver, gold, palladium, platinum, and copper. In this thesis, we also present fabrication of metallic silver nanowires templated on artificially designed one-dimensional DNA

  11. Fabrication of microfluidic mixers and artificial vasculatures using a high-brightness diode-pumped Nd:YAG laser direct write method.

    PubMed

    Lim, Daniel; Kamotani, Yoko; Cho, Brenda; Mazumder, Jyotirmoy; Takayama, Shuichi

    2003-11-01

    This paper describes a direct write laser technology, which is fast and flexible, for fabricating multiple-level microfluidic channels. A high brightness diode-pumped Nd-YAG laser with slab geometry was used for its excellent beam quality. Channels with flat walls and staggered herringbone ridges on the floor have been successfully fabricated and their ability to perform passive mixing of liquid is discussed. Also, a multi-width multi-depth microchannel has been fabricated to generate biomimetic vasculatures whose channel diameters change according to Murray's law, which states that the cube of the radius of a parent vessel equals the sum of the cubes of the radii of the daughters. The multi-depth architecture allows for flow patterns to resemble physiological vascular systems with lower overall resistance and more uniform flow velocities throughout the network compared to planar patterning techniques which generate uniformly thin channels. The ability to directly fabricate multiple level structures using relatively straightforward laser technology enhances our ability to rapidly prototype complex lab-on-a-chip systems and to develop physiological microfluidic structures for tissue engineering and investigations in biomedical fluidics problems. PMID:15007466

  12. Nanosurfaces and nanostructures for artificial orthopedic implants.

    PubMed

    Streicher, Robert M; Schmidt, Martin; Fiorito, Silvana

    2007-12-01

    Nanomaterials and structures, such as nanoparticles, nanofibers, nanosurfaces, nanocoatings, nanoscaffolds and nanocomposites, are considered for various applications in orthopedics and traumatology. This review looks at proposed nanotechnology inspired applications for implants from the perspective of the orthopedic industry. Investigations support consistently the theory that most nanomaterials in various physical forms are able to enhance the cell response selectively for biological tissue integration or increase the strength and wear resistance of current orthopedic materials. At this stage, most of the studies are at the laboratory scale or in early in vivo testing. Significant basic and applied research and development is needed to realize their full clinical potential and biological, manufacturing, economic and regulatory issues have to be addressed. Nevertheless, a crucial factor for success is well-coordinated multimethod and multidiscipline teamwork with profound industrial and medical expertise. PMID:18095851

  13. Artificial Limbs

    MedlinePlus

    ... you are missing an arm or leg, an artificial limb can sometimes replace it. The device, which ... activities such as walking, eating, or dressing. Some artificial limbs let you function nearly as well as ...

  14. Artificial Intelligence.

    ERIC Educational Resources Information Center

    Waltz, David L.

    1982-01-01

    Describes kinds of results achieved by computer programs in artificial intelligence. Topics discussed include heuristic searches, artificial intelligence/psychology, planning program, backward chaining, learning (focusing on Winograd's blocks to explore learning strategies), concept learning, constraint propagation, language understanding…

  15. Enhancement of the mechanical properties of AZ31 magnesium alloy via nanostructured hydroxyapatite thin films fabricated via radio-frequency magnetron sputtering.

    PubMed

    Surmeneva, M A; Tyurin, A I; Mukhametkaliyev, T M; Pirozhkova, T S; Shuvarin, I A; Syrtanov, M S; Surmenev, R A

    2015-06-01

    The structure, composition and morphology of a radio-frequency (RF) magnetron sputter-deposited dense nano-hydroxyapatite (HA) coating that was deposited on the surface of an AZ31 magnesium alloy were characterized using AFM, SEM, EDX and XRD. The results obtained from SEM and XRD experiments revealed that the bias applied during the deposition of the HA coating resulted in a decrease in the grain and crystallite size of the film having a crucial role in enhancing the mechanical properties of the fabricated biocomposites. A maximum hardness of 9.04 GPa was found for the HA coating, which was prepared using a bias of -50 V. The hardness of the HA film deposited on the grounded substrate (GS) was found to be 4.9 GPa. The elastic strain to failure (H/E) and the plastic deformation resistance (H(3)/E(2)) for an indentation depth of 50 nm for the HA coating fabricated at a bias of -50 V was found to increase by ~30% and ~74%, respectively, compared with the coating deposited at the GS holder. The nanoindentation tests demonstrated that all of the HA coatings increased the surface hardness on both the microscale and the nanoscale. Therefore, the results revealed that the films deposited on the surface of the AZ31 magnesium alloy at a negative substrate bias can significantly enhance the wear resistance of this resorbable alloy. PMID:25792410

  16. Nano-structural Characteristics of N-doped ZnO Thin Films and Fabrication of Film Bulk Acoustic Resonator Devices

    SciTech Connect

    Lee, E. J.; Zhang, R. R.; Yoon, G. W.; Park, J. D.

    2011-12-23

    N-doped ZnO thin films (ZnO:N) with c-axis preferred orientation were prepared on p-Si(100) wafers, using an RF magnetron sputter deposition. For ZnO deposition, N{sub 2}O gas was employed as a dopant source and various deposition conditions such as N{sub 2}O gas fraction and RF power were applied. In addition, the film bulk acoustic resonator (FBAR) devices with three kinds of top electrodes patterns were fabricated by using the N-doped ZnO thin films as the piezoelectric layers. The depth profiles of the nitrogen [N] atoms incorporated into the ZnO thin films were investigated by an Auger Electron Spectroscopy (AES) and the nano-scale structural characteristics of the N-doped ZnO (ZnO:N) thin films were also investigated by a scanning electron microscope (SEM) technique. The fabricated resonators were evaluated by measuring the return loss (S{sub 11}) characteristics using a probe station and E8361A PNA Network Analyzer.

  17. Microstructure and Mechanical Properties of Nanostructured 1050/6061 Aluminum Alloy Fabricated by Four-Layer Stack Accumulative Roll-Bonding.

    PubMed

    Lee, Seong-Hee; Lee, Seong Ro

    2015-07-01

    An ultrafine grained AA1050/AA6061 Al alloy sheet was successfully fabricated by four-layer stack ARB process. The ARB of AA1050 and AA6061 alloy sheets was performed up to 3 cycles without a lubricant at ambient temperature. The sample fabricated by the ARB was a multi-layer aluminum alloy sheet in which AA1050 and AA6061 layers are alternately stacked. The layer thickness of the each alloy became thinner and elongated to the rolling direction with increasing the number of ARB cycles. The tensile strength increased with the ARB, it reached about 347 MPa which is almost 2.4 times that of the starting material. The grain size decreased with increasing of the number of ARB cycles, became about 190 nm in thickness after 3 cycles. The variation of mechanical properties with the ARB was similar to those of the other ARB processed materials. However, the texture development was different from those of the conventional ARB processed materials. PMID:26373070

  18. Nanostructured Substrates for Optical Sensing

    PubMed Central

    Kemling, Jonathan W.; Qavi, Abraham J.; Bailey, Ryan C.

    2011-01-01

    Sensors that change color have the advantages of versatility, ease of use, high sensitivity, and low cost. The recent development of optically based chemical sensing platforms has increasingly employed substrates manufactured with advanced processing or fabrication techniques to provide precise control over shape and morphology of the sensor micro- and nano-structure. New sensors have resulted with improved capabilities for a number of sensing applications, including the detection of biomolecules and environmental monitoring. This perspective focuses on recent optical sensor devices that utilize nanostructured substrates. PMID:22174955

  19. Artificial Intelligence.

    ERIC Educational Resources Information Center

    Information Technology Quarterly, 1985

    1985-01-01

    This issue of "Information Technology Quarterly" is devoted to the theme of "Artificial Intelligence." It contains two major articles: (1) Artificial Intelligence and Law" (D. Peter O'Neill and George D. Wood); (2) "Artificial Intelligence: A Long and Winding Road" (John J. Simon, Jr.). In addition, it contains two sidebars: (1) "Calculating and…

  20. Micro-scratch and corrosion behavior of functionally graded HA-TiO2 nanostructured composite coatings fabricated by electrophoretic deposition.

    PubMed

    Farnoush, Hamidreza; Aghazadeh Mohandesi, Jamshid; Çimenoğlu, Hüseyin

    2015-06-01

    In the present study, functionally graded coatings of HA/TiO2 nanoparticles and HA-TiO2 nanocomposite coatings with 0, 10 and 20 wt% of TiO2 were fabricated by electrophoretic deposition on Ti-6Al-4V substrate. The functionally graded structure of HA/TiO2 coatings was formed by gradual addition of HA suspension into the deposition cell containing TiO2 nanoparticles. Micro-scratch test results showed the highest critical distances of crack initiation and delamination, normal load before failure and critical contact pressures for functionally graded coating. It was observed that the improvement of adhesion strength and fracture toughness of functionally graded coatings would be due to the reduction of thermal expansion coefficient mismatch between Ti-6Al-4V substrate and HA. The results of potentiodynamic polarization measurements showed that the graded structure of the coating could efficiently increase the corrosion resistance of substrate. PMID:25771254

  1. Antibacterial Au nanostructured surfaces.

    PubMed

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-02-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies. PMID:26648134

  2. Nanostructuring steel for injection molding tools

    NASA Astrophysics Data System (ADS)

    Al-Azawi, A.; Smistrup, K.; Kristensen, A.

    2014-05-01

    The production of nanostructured plastic items by injection molding with ridges down to 400 nm in width, which is the smallest line width replicated from nanostructured steel shims, is presented. Here we detail a micro-fabrication method where electron beam lithography, nano-imprint lithography and ion beam etching are combined to nanostructure the planar surface of a steel wafer. Injection molded plastic parts with enhanced surface properties, like anti-reflective, superhydrophobic and structural colors can be achieved by micro- and nanostructuring the surface of the steel molds. We investigate the minimum line width that can be realized by our fabrication method and the influence of etching angle on the structure profile during the ion beam etching process. Trenches down to 400 nm in width have been successfully fabricated into a 316 type electro-polished steel wafer. Afterward a plastic replica has been produced by injection molding with good structure transfer fidelity. Thus we have demonstrated that by utilizing well-established fabrication techniques, nanostructured steel shims that are used in injection molding, a technique that allows low cost mass fabrication of plastic items, are produced.

  3. Fabrication and characterization of polycaprolactone cross- linked and highly-aligned 3-D artificial scaffolds for bone tissue regeneration via electrospinning technology

    NASA Astrophysics Data System (ADS)

    Gorodzha, S. N.; Surmeneva, M. A.; Surmenev, R. A.

    2015-11-01

    Novel technologies allowed the scientific community to develop scaffolds for regeneration of bone tissue. A successful scaffold should possess specific macroscopic geometry and internal architecture to perform biological and biophysical functions. In this study the process of polycaprolactone microfibrous development with either cross-linked or highly-aligned three-dimensional artificial mats via electrospinning technology for potential application in tissue engineering is described. The morphology and size of electrospun fibers were assessed systematically by varying the rotation speed of grounded collector. It was found that the diameter of the fibers decreased by increasing the rotation speed of collector. The morphology of the fibers changed from cross-linked to highly-aligned at appr. 1000-1100 rpm.

  4. Hierarchically nanostructured materials for sustainable environmental applications

    PubMed Central

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-01-01

    This review presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions, and multiple functionalities toward water remediation, biosensing, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing, and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology. PMID:24790946

  5. Hierarchically Nanostructured Materials for Sustainable Environmental Applications

    NASA Astrophysics Data System (ADS)

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-11-01

    This article presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions and multiple functionalities towards water remediation, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology.

  6. Hierarchically nanostructured materials for sustainable environmental applications.

    PubMed

    Ren, Zheng; Guo, Yanbing; Liu, Cai-Hong; Gao, Pu-Xian

    2013-01-01

    This review presents a comprehensive overview of the hierarchical nanostructured materials with either geometry or composition complexity in environmental applications. The hierarchical nanostructures offer advantages of high surface area, synergistic interactions, and multiple functionalities toward water remediation, biosensing, environmental gas sensing and monitoring as well as catalytic gas treatment. Recent advances in synthetic strategies for various hierarchical morphologies such as hollow spheres and urchin-shaped architectures have been reviewed. In addition to the chemical synthesis, the physical mechanisms associated with the materials design and device fabrication have been discussed for each specific application. The development and application of hierarchical complex perovskite oxide nanostructures have also been introduced in photocatalytic water remediation, gas sensing, and catalytic converter. Hierarchical nanostructures will open up many possibilities for materials design and device fabrication in environmental chemistry and technology. PMID:24790946

  7. Nano-structure fabrication of GaAs using AFM tip-induced local oxidation method: different doping types and plane orientations

    PubMed Central

    2011-01-01

    In this study, we have fabricated nano-scaled oxide structures on GaAs substrates that are doped in different conductivity types of p- and n-types and plane orientations of GaAs(100) and GaAs(711), respectively, using an atomic force microscopy (AFM) tip-induced local oxidation method. The AFM-induced GaAs oxide patterns were obtained by varying applied bias from approximately 5 V to approximately 15 V and the tip loading forces from 60 to 180 nN. During the local oxidation, the humidity and the tip scan speed are fixed to approximately 45% and approximately 6.3 μm/s, respectively. The local oxidation rate is further improved in p-type GaAs compared to n-type GaAs substrates whereas the rate is enhanced in GaAs(100) compared to and GaAs(711), respectively, under the identical conditions. In addition, the oxide formation mechanisms in different doping types and plane orientations were investigated and compared with two-dimensional simulation results. PMID:21978373

  8. Fabrication of Well-Ordered Three-Phase Boundary with Nanostructure Pore Array for Mixed Potential-Type Zirconia-Based NO2 Sensor.

    PubMed

    Wang, Bin; Liu, Fangmeng; Yang, Xue; Guan, Yehui; Ma, Ce; Hao, Xidong; Liang, Xishuang; Liu, Fengmin; Sun, Peng; Zhang, Tong; Lu, Geyu

    2016-07-01

    A well-ordered porous three-phase boundary (TPB) was prepared with a polystyrene sphere as template and examined to improve the sensitivity of yttria-stabilized zirconia (YSZ)-based mixed-potential-type NO2 sensor due to the increase of the electrochemical reaction active sites. The shape of pore array on the YSZ substrate surface can be controlled through changing the concentration of the precursor solution (Zr(4+)/Y(3+) = 23 mol/L/4 mol/L) and treatment conditions. An ordered hemispherical array was obtained when CZr(4+) = 0.2 mol/L. The processed YSZ substrates were used to fabricate the sensors, and different sensitivities caused by different morphologies were tested. The sensor with well-ordered porous TPB exhibited the highest sensitivity to NO2 with a response value of 105 mV to 100 ppm of NO2, which is approximately twice as much as the smooth one. In addition, the sensor also showed good stability and speedy response kinetics. All these enhanced sensing properties might be due to the structure and morphology of the enlarged TPB. PMID:27294685

  9. Designed fabrication of unique eccentric mesoporous silica nanocluster-based core-shell nanostructures for pH-responsive drug delivery.

    PubMed

    Chen, Lulu; Li, Lu; Zhang, Lingyu; Xing, Shuangxi; Wang, Tingting; Wang, Y Andrew; Wang, Chungang; Su, Zhongmin

    2013-08-14

    A novel and facile strategy using poly(acrylic acid) (PAA) as a nanoreactor and template has been proposed and applied for the first time to fabricate a novel and unique class of multifunctional eccentric Fe3O4@PAA/SiO2 core-shell nanoclusters (NCs) consisting of a single Fe3O4 nanoparticle (NP), PAA, and eccentric SiO2 NCs that are composed of a large number of small fluorescent SiO2 NPs. Interestingly, the resulting eccentric PAA shell around Fe3O4 NPs as a high water-absorbent polymer is like a "reservoir" to absorb and retain water molecules inside its net structure to confine the growth of small SiO2 NPs inside the PAA networks, resulting in the formation of an eccentric SiO2 NC with aggregated pores. The thicknesses of uniform and well-dispersed SiO2 NCs can also be precisely controlled by varying the amount of tetraethyl orthosilicate (TEOS). Importantly, the synthetic method has been confirmed to be universal and extended to other functional NPs with different compositions and shapes as eccentric cores. Furthermore, the as-prepared multifunctional eccentric Fe3O4@PAA/SiO2 core-shell NCs combined fluorescence imaging, ultrahigh drug loading capacity (1.13 mg doxorubicin/mg eccentric NCs), and pH-responsive drug release into one were taken as an example to study the applications in simultaneous fluorescence imaging and pH responsive drug delivery into prostate cancer PC3M cells. PMID:23808730

  10. Fabrication of dense α-alumina layer on Ti-6Al-4V alloy hybrid for bearing surfaces of artificial hip joint.

    PubMed

    Khanna, Rohit; Kokubo, Tadashi; Matsushita, Tomiharu; Takadama, Hiroaki

    2016-12-01

    Recent advances in hip replacements are focused towards producing reliable bearing surfaces to enhance their longevity. In this perspective, progressive attempts have been made to improve the wear resistance of polyethylene to eliminate osteolysis and mechanical reliability of brittle alumina ceramics, but in vain. It is proposed that both high wear resistance and mechanical reliability can be retained if a thin layer of dense alumina is formed onto high toughness Ti-6Al-4V alloy. For this purpose, we devised a unique methodology in which a layer of Al metal was deposited onto the Ti alloy substrate by cold spraying (CS), followed by a heat treatment to form Al3Ti reaction layer at their interface to improve adhesion and subsequent micro-arc oxidation (MAO) treatment to transform Al to alumina layer. An optimal MAO treatment of cold sprayed Al formed an adherent and dense α-alumina layer with high Vickers hardness matching with that of sintered alumina used as a femoral head. Structure-phase-property relationships in dense α-alumina layer have been revealed and discussed in the light of our research findings. The designed alumina/Ti alloy hybrid might be a potential candidate for reliable bearing surfaces of artificial hip joint. PMID:27612821

  11. Establishing a Scientific Basis for Optimizing Compositions, Process Paths and Fabrication Methods for Nanostructured Ferritic Alloys for Use in Advanced Fission Energy Systems

    SciTech Connect

    Odette, G Robert; Cunningham, Nicholas J., Wu, Yuan; Etienne, Auriane; Stergar, Erich; Yamamoto, Takuya

    2012-02-21

    The broad objective of this NEUP was to further develop a class of 12-15Cr ferritic alloys that are dispersion strengthened and made radiation tolerant by an ultrahigh density of Y-Ti-O nanofeatures (NFs) in the size range of less than 5 nm. We call these potentially transformable materials nanostructured ferritic alloys (NFAs). NFAs are typically processed by ball milling pre-alloyed rapidly solidified powders and yttria (Y2O3) powders. Proper milling effectively dissolves the Ti, Y and O solutes that precipitate as NFs during hot consolidation. The tasks in the present study included examining alternative processing paths, characterizing and optimizing the NFs and investigating solid state joining. Alternative processing paths involved rapid solidification by gas atomization of Fe, 14% Cr, 3% W, and 0.4% Ti powders that are also pre-alloyed with 0.2% Y (14YWT), where the compositions are in wt.%. The focus is on exploring the possibility of minimizing, or even eliminating, the milling time, as well as producing alloys with more homogeneous distributions of NFs and a more uniform, fine grain size. Three atomization environments were explored: Ar, Ar plus O (Ar/O) and He. The characterization of powders and alloys occurred through each processing step: powder production by gas atomization; powder milling; and powder annealing or hot consolidation by hot isostatic pressing (HIPing) or hot extrusion. The characterization studies of the materials described here include various combinations of: a) bulk chemistry; b) electron probe microanalysis (EPMA); c) atom probe tomography (APT); d) small angle neutron scattering (SANS); e) various types of scanning and transmission electron microscopy (SEM and TEM); and f) microhardness testing. The bulk chemistry measurements show that preliminary batches of gas-atomized powders could be produced within specified composition ranges. However, EPMA and TEM showed that the Y is heterogeneously distributed and phase separated, but

  12. Phonon engineering for nanostructures.

    SciTech Connect

    Aubry, Sylvie; Friedmann, Thomas Aquinas; Sullivan, John Patrick; Peebles, Diane Elaine; Hurley, David H.; Shinde, Subhash L.; Piekos, Edward Stanley; Emerson, John Allen

    2010-01-01

    Understanding the physics of phonon transport at small length scales is increasingly important for basic research in nanoelectronics, optoelectronics, nanomechanics, and thermoelectrics. We conducted several studies to develop an understanding of phonon behavior in very small structures. This report describes the modeling, experimental, and fabrication activities used to explore phonon transport across and along material interfaces and through nanopatterned structures. Toward the understanding of phonon transport across interfaces, we computed the Kapitza conductance for {Sigma}29(001) and {Sigma}3(111) interfaces in silicon, fabricated the interfaces in single-crystal silicon substrates, and used picosecond laser pulses to image the thermal waves crossing the interfaces. Toward the understanding of phonon transport along interfaces, we designed and fabricated a unique differential test structure that can measure the proportion of specular to diffuse thermal phonon scattering from silicon surfaces. Phonon-scale simulation of the test ligaments, as well as continuum scale modeling of the complete experiment, confirmed its sensitivity to surface scattering. To further our understanding of phonon transport through nanostructures, we fabricated microscale-patterned structures in diamond thin films.

  13. Bilayer oxidized regenerated cellulose/poly ε-caprolactone knitted fabric-reinforced composite for use as an artificial dural substitute.

    PubMed

    Suwanprateeb, Jintamai; Luangwattanawilai, Ticomporn; Theeranattapong, Thunyanun; Suvannapruk, Waraporn; Chumnanvej, Sorayouth; Hemstapat, Warinkarn

    2016-07-01

    A novel bilayer knitted fabric-reinforced composite for potentially being used as a dural substitute was developed by solution infiltration of oxidized regenerated cellulose knitted fabric (ORC) with poly ε-caprolactone (PCL) solution at various concentrations ranging 10-40 g/100 mL. It was found that the density of all formulations did not differ significantly and was lower than that of the human dura. Microstructure of the samples typically comprised a bilayer structure having a nonporous PCL layer on one side and the ORC/PCL composite layer on another side. Tensile modulus and strength of the samples initially decreased with increasing PCL solution concentration for up to 20 g/100 mL and re-increased again with further increasing PCL solution concentration. Strain at break of all formulations were not significantly different. Watertight test revealed that all composites could prevent leakage at the pressure within the normal range of intracranial pressure. In vitro degradation study revealed that the weight loss percentage and change in tensile properties of all samples displayed biphasic profile comprising an initially rapid decrease and followed by a gradual decrease with incubation times afterward. Micro and macro porous channels were observed to be in situ generated in the composite layer by ORC dissolution and PCL resorption during degradation while nonporous layer remained relatively unchanged. The degradation rate was found to decrease with increasing PCL solution concentration. In vitro biocompatibility using alamar blue assay on selected samples showed that fibroblasts could attach and proliferate well at all incubation periods. PMID:27278580

  14. Self-assembled catalytic DNA nanostructures for synthesis of para-directed polyaniline.

    PubMed

    Wang, Zhen-Gang; Zhan, Pengfei; Ding, Baoquan

    2013-02-26

    Templated synthesis has been considered as an efficient approach to produce polyaniline (PANI) nanostructures. The features of DNA molecules enable a DNA template to be an intriguing template for fabrication of emeraldine PANI. In this work, we assembled HRP-mimicking DNAzyme with different artificial DNA nanostructures, aiming to manipulate the molecular structures and morphologies of PANI nanostructures through the controlled DNA self-assembly. UV-vis absorption spectra were used to investigate the molecular structures of PANI and monitor kinetic growth of PANI. It was found that PANI was well-doped at neutral pH and the redox behaviors of the resultant PANI were dependent on the charge density of the template, which was controlled by the template configurations. CD spectra indicated that the PANI threaded tightly around the helical DNA backbone, resulting in the right handedness of PANI. These reveal the formation of the emeraldine form of PANI that was doped by the DNA. The morphologies of the resultant PANI were studied by AFM and SEM. It was concluded from the imaging and spectroscopic kinetic results that PANI grew preferably from the DNAzyme sites and then expanded over the template to form 1D PANI nanostructures. The strategy of the DNAzyme-DNA template assembly brings several advantages in the synthesis of para-coupling PANI, including the region-selective growth of PANI, facilitating the formation of a para-coupling structure and facile regulation. We believe this study contributes significantly to the fabrication of doped PANI nanopatterns with controlled complexity, and the development of DNA nanotechnology. PMID:23272944

  15. Thermoelectric characterization and fabrication of nanostructured p-type Bi0.5Sb1.5Te3 and n-type Bi2Te3 thin film thermoelectric energy generator with an in-plane planar structure

    NASA Astrophysics Data System (ADS)

    Park, No-Won; Park, Tae-Hyun; Ahn, Jay-Young; Kang, So-Hyeon; Lee, Won-Yong; Yoon, Young-Gui; Yoon, Soon-Gil; Lee, Sang-Kwon

    2016-06-01

    This paper presents in-plane bismuth-telluride-based thermoelectric (TE) energy generators fabricated using metal-shadow and radio-frequency sputtering methods at room temperature. The TE energy generators consist of four couples of 300-nm-thick nanostructured Bi2Te3 (n-BT) and Bi0.5Sb1.5Te3 (p-BST) thin films used as n-type and p-type materials, respectively, on a Si substrate for the p/n junctions of the TE energy generators. Furthermore, the effect of annealing treatment of both n-BT and p-BST thin films on the electrical and TE properties as well as the TE performance of the TE energy generators is discussed. By varying the temperature between the hot and cold junction legs of the n-BT/p-BST in-plane TE energy generators annealed at 200 °C, the maximum output voltage and power are determined to be ˜3.6 mV and ˜1.1 nW, respectively, at a temperature difference of 50 K. The output powers increased by ˜590% compared to that of the as-grown TE generator at a temperature difference of 90 K. This improvement in the TE performance is attributed to the enhancement of the electrical conductivity after heat treatment. From a numerical simulation conducted using a commercial software (COMSOL), we are confident that it plays a crucial role in determining the dimension (i.e., thickness of each leg) and material properties of both n-BT and p-BST materials of the in-plane TE energy generators.

  16. Integration of Nanostructures into Microsensor Devices on Whole Wafers

    NASA Technical Reports Server (NTRS)

    Biaggi-Labiosa, Azlin M.; Evans, Laura J.; Berger, Gordon M.; Hunter, Gary W.

    2015-01-01

    Chemical sensors are used in a wide variety of applications, such as environmental monitoring, fire detection, emission monitoring, and health monitoring. The fabrication of chemical sensors involving nanostructured materials holds the potential for the development of sensor systems with unique properties and improved performance. However, the fabrication and processing of nanostructures for sensor applications currently are limited in the ability to control their location on the sensor, which in turn hinders the progress for batch fabrication. This report discusses the advantages of using nanomaterials in sensor designs, some of the challenges encountered with the integration of nanostructures into microsensor / devices, and then briefly describes different methods attempted by other groups to address this issue. Finally, this report will describe how our approach for the controlled alignment of nanostructures onto a sensor platform was applied to demonstrate an approach for the mass production of sensors with nanostructures.

  17. PREFACE: Self-organized nanostructures

    NASA Astrophysics Data System (ADS)

    Rousset, Sylvie; Ortega, Enrique

    2006-04-01

    In order to fabricate ordered arrays of nanostructures, two different strategies might be considered. The `top-down' approach consists of pushing the limit of lithography techniques down to the nanometre scale. However, beyond 10 nm lithography techniques will inevitably face major intrinsic limitations. An alternative method for elaborating ultimate-size nanostructures is based on the reverse `bottom-up' approach, i.e. building up nanostructures (and eventually assemble them to form functional circuits) from individual atoms or molecules. Scanning probe microscopies, including scanning tunnelling microscopy (STM) invented in 1982, have made it possible to create (and visualize) individual structures atom by atom. However, such individual atomic manipulation is not suitable for industrial applications. Self-assembly or self-organization of nanostructures on solid surfaces is a bottom-up approach that allows one to fabricate and assemble nanostructure arrays in a one-step process. For applications, such as high density magnetic storage, self-assembly appears to be the simplest alternative to lithography for massive, parallel fabrication of nanostructure arrays with regular sizes and spacings. These are also necessary for investigating the physical properties of individual nanostructures by means of averaging techniques, i.e. all those using light or particle beams. The state-of-the-art and the current developments in the field of self-organization and physical properties of assembled nanostructures are reviewed in this issue of Journal of Physics: Condensed Matter. The papers have been selected from among the invited and oral presentations of the recent summer workshop held in Cargese (Corsica, France, 17-23 July 2005). All authors are world-renowned in the field. The workshop has been funded by the Marie Curie Actions: Marie Curie Conferences and Training Courses series named `NanosciencesTech' supported by the VI Framework Programme of the European Community, by

  18. Sub-threshold signal processing in arrays of non-identical nanostructures.

    PubMed

    Cervera, Javier; Manzanares, José A; Mafé, Salvador

    2011-10-28

    Weak input signals are routinely processed by molecular-scaled biological networks composed of non-identical units that operate correctly in a noisy environment. In order to show that artificial nanostructures can mimic this behavior, we explore theoretically noise-assisted signal processing in arrays of metallic nanoparticles functionalized with organic ligands that act as tunneling junctions connecting the nanoparticle to the external electrodes. The electronic transfer through the nanostructure is based on the Coulomb blockade and tunneling effects. Because of the fabrication uncertainties, these nanostructures are expected to show a high variability in their physical characteristics and a diversity-induced static noise should be considered together with the dynamic noise caused by thermal fluctuations. This static noise originates from the hardware variability and produces fluctuations in the threshold potential of the individual nanoparticles arranged in a parallel array. The correlation between different input (potential) and output (current) signals in the array is analyzed as a function of temperature, applied voltage, and the variability in the electrical properties of the nanostructures. Extensive kinetic Monte Carlo simulations with nanostructures whose basic properties have been demonstrated experimentally show that variability can enhance the correlation, even for the case of weak signals and high variability, provided that the signal is processed by a sufficiently high number of nanostructures. Moderate redundancy permits us not only to minimize the adverse effects of the hardware variability but also to take advantage of the nanoparticles' threshold fluctuations to increase the detection range at low temperatures. This conclusion holds for the average behavior of a moderately large statistical ensemble of non-identical nanostructures processing different types of input signals and suggests that variability could be beneficial for signal processing

  19. Polish artificial heart program.

    PubMed

    El Fray, Miroslawa; Czugala, Monika

    2012-01-01

    Despite significant advances in the development of artificial heart substitutes, anthrombogenic materials and surfaces remain to be the main challenge for implants, which can prevent thrombosis that leads to rejection. The goal of material engineering is essentially to design polymeric materials of high durability and optimal thrombogenicity in mechanical heart prosthesis, being developed recently in a frame of the polish artificial heart program. For these reasons, various surface modifications are being continuously developed for a 'gold standard' material, which is a polyurethane (PU) thermoplastic elastomer and they will be shortly reviewed. However, new polymeric materials can meet medical word's attention if they are able to provide similar or better characteristics in term of bulk and surface properties. Specifically, if they will show appropriate surface topography, which is the most influential in determining the response of live tissues toward biomaterials. Nanostructured polyester thermoplastic elastomers of high biodurability as an alternative to PU materials for artificial heart are challenging new materials, and they will be discussed briefly. PMID:22110047

  20. Artificial Intelligence.

    ERIC Educational Resources Information Center

    Thornburg, David D.

    1986-01-01

    Overview of the artificial intelligence (AI) field provides a definition; discusses past research and areas of future research; describes the design, functions, and capabilities of expert systems and the "Turing Test" for machine intelligence; and lists additional sources for information on artificial intelligence. Languages of AI are also briefly…

  1. Artificial Intelligence.

    ERIC Educational Resources Information Center

    Smith, Linda C.; And Others

    1988-01-01

    A series of articles focuses on artificial intelligence research and development to enhance information systems and services. Topics discussed include knowledge base designs, expert system development tools, natural language processing, expert systems for reference services, and the role that artificial intelligence concepts should have in…

  2. Artificial intelligence

    SciTech Connect

    Firschein, O.

    1984-01-01

    This book presents papers on artificial intelligence. Topics considered include knowledge engineering, expert systems, applications of artificial intelligence to scientific reasoning, planning and problem solving, error recovery in robots through failure reason analysis, programming languages, natural language, speech recognition, map-guided interpretation of remotely-sensed imagery, and image understanding architectures.

  3. Nanostructured photovoltaics

    NASA Astrophysics Data System (ADS)

    Fu, Lan; Tan, H. Hoe; Jagadish, Chennupati

    2013-01-01

    Energy and the environment are two of the most important global issues that we currently face. The development of clean and sustainable energy resources is essential to reduce greenhouse gas emission and meet our ever-increasing demand for energy. Over the last decade photovoltaics, as one of the leading technologies to meet these challenges, has seen a continuous increase in research, development and investment. Meanwhile, nanotechnology, which is considered to be the technology of the future, is gradually revolutionizing our everyday life through adaptation and incorporation into many traditional technologies, particularly energy-related technologies, such as photovoltaics. While the record for the highest efficiency is firmly held by multijunction III-V solar cells, there has never been a shortage of new research effort put into improving the efficiencies of all types of solar cells and making them more cost effective. In particular, there have been extensive and exciting developments in employing nanostructures; features with different low dimensionalities, such as quantum wells, nanowires, nanotubes, nanoparticles and quantum dots, have been incorporated into existing photovoltaic technologies to enhance their performance and/or reduce their cost. Investigations into light trapping using plasmonic nanostructures to effectively increase light absorption in various solar cells are also being rigorously pursued. In addition, nanotechnology provides researchers with great opportunities to explore the new ideas and physics offered by nanostructures to implement advanced solar cell concepts such as hot carrier, multi-exciton and intermediate band solar cells. This special issue of Journal of Physics D: Applied Physics contains selected papers on nanostructured photovoltaics written by researchers in their respective fields of expertise. These papers capture the current excitement, as well as addressing some open questions in the field, covering topics including the

  4. Biofluid lubrication for artificial joints

    NASA Astrophysics Data System (ADS)

    Pendleton, Alice Mae

    This research investigated biofluid lubrication related to artificial joints using tribological and rheological approaches. Biofluids studied here represent two categories of fluids, base fluids and nanostructured biofluids. Base fluids were studied through comparison of synthetic fluids (simulated body fluid and hyaluronic acid) as well as natural biofluids (from dogs, horses, and humans) in terms of viscosity and fluid shear stress. The nano-structured biofluids were formed using molecules having well-defined shapes. Understanding nano-structured biofluids leads to new ways of design and synthesis of biofluids that are beneficial for artificial joint performance. Experimental approaches were utilized in the present research. This includes basic analysis of biofluids' property, such as viscosity, fluid shear stress, and shear rate using rheological experiments. Tribological investigation and surface characterization were conducted in order to understand effects of molecular and nanostructures on fluid lubrication. Workpiece surface structure and wear mechanisms were investigated using a scanning electron microscope and a transmission electron microscope. The surface topography was examined using a profilometer. The results demonstrated that with the adding of solid additives, such as crown ether or fullerene acted as rough as the other solids in the 3-body wear systems. In addition, the fullerene supplied low friction and low wear, which designates the lubrication purpose of this particular particle system. This dissertation is constructed of six chapters. The first chapter is an introduction to body fluids, as mentioned earlier. After Chapter II, it examines the motivation and approach of the present research, Chapter III discusses the experimental approaches, including materials, experimental setup, and conditions. In Chapter IV, lubrication properties of various fluids are discussed. The tribological properties and performance nanostructured biofluids are

  5. Plasmonic Nanostructures for Biosensor Applications

    NASA Astrophysics Data System (ADS)

    Gadde, Akshitha

    Improving the sensitivity of existing biosensors is an active research topic that cuts across several disciplines, including engineering and biology. Optical biosensors are the one of the most diverse class of biosensors which can be broadly categorized into two types based on the detection scheme: label-based and label-free detection. In label-based detection, the target bio-molecules are labeled with dyes or tags that fluoresce upon excitation, indicating the presence of target molecules. Label-based detection is highly-sensitive, capable of single molecule detection depending on the detector type used. One method of improving the sensitivity of label-based fluorescence detection is by enhancement of the emission of the labels by coupling them with metal nanostructures. This approach is referred as plasmon-enhanced fluorescence (PEF). PEF is achieved by increasing the electric field around the nano metal structures through plasmonics. This increased electric field improves the enhancement from the fluorophores which in turn improves the photon emission from the fluorophores which, in turn, improves the limit of detection. Biosensors taking advantage of the plasmonic properties of metal films and nanostructures have emerged an alternative, low-cost, high sensitivity method for detecting labeled DNA. Localized surface plasmon resonance (LSPR) sensors employing noble metal nanostructures have recently attracted considerable attention as a new class of plasmonic nanosensors. In this work, the design, fabrication and characterization of plasmonic nanostructures is carried out. Finite difference time domain (FDTD) simulations were performed using software from Lumerical Inc. to design a novel LSPR structure that exhibit resonance overlapping with the absorption and emission wavelengths of quantum dots (QD). Simulations of a composite Au/SiO2 nanopillars on silicon substrate were performed using FDTD software to show peak plasmonic enhancement at QD emission wavelength

  6. Zinc oxide nanostructures and nanoengineering

    NASA Astrophysics Data System (ADS)

    Banerjee, Debasish

    ZnO is a large band-gap (3.37 eV) semiconductor, a potentially important material for numerous optoelectronic applications. Nanostructures, by definition are the structures having at least one dimension between 1--100 nm. In this thesis we will investigate a brief account of the strategies to grow ZnO nanostructures. Since invariably nanomaterial properties tend to change significantly during scale-up from development on limited volume equipment. Goal of this study is to demonstrate a practical technique which is able to synthesize large quantities of nanowires while keeping the unique properties of nano-sized materials. Using ZnO as an example, we discussed a strategy to produce nanowires in gram quantity. Ability to define position, size, and density of nanostructures on surfaces enable detailed studies of the properties of individual sites as well as collective properties of the assembly. These periodic structures are usually manufactured using electron beam lithography, photolithography, or x-ray lithography techniques. These methods allow fabrication of nanostructures and provide highly reproducible results. However, they are mostly not scalable to large areas, and are limited by a multistage, time-consuming, and expensive preparation procedure. We described an unique technique combining nanosphere self-assembly lithography and vapor-liquid-solid (VLS) approach of fabricating periodic array of catalyst dots in various geometry and subsequently grow vertically aligned ZnO nanowires in a large area hoping to achieve enhanced ultraviolet lasing and many other photonic devices. ZnO being a transparent conducting oxide, the fabrication of ZnO field emitters can be easily integrated with ITO and ZnO thin film fabrication process. Thus a low cost solution for fabrication of field emission display can be realized using ZnO nanowires as field emitters. There have been several demonstrations of using ZnO nanowires as field emitters. However no significant improvement in

  7. Artificial urushi.

    PubMed

    Kobayashi, S; Uyama, H; Ikeda, R

    2001-11-19

    A new concept for the design and laccase-catalyzed preparation of "artificial urushi" from new urushiol analogues is described. The curing proceeded under mild reaction conditions to produce the very hard cross-linked film (artificial urushi) with a high gloss surface. A new cross-linkable polyphenol was synthesized by oxidative polymerization of cardanol, a phenol derivative from cashew-nut-shell liquid, by enzyme-related catalysts. The polyphenol was readily cured to produce the film (also artificial urushi) showing excellent dynamic viscoelasticity. PMID:11763444

  8. Fabricating superhydrophilic wool fabrics.

    PubMed

    Chen, Dong; Tan, Longfei; Liu, Huiyu; Hu, Junyan; Li, Yi; Tang, Fangqiong

    2010-04-01

    A simple method for fabricating environmentally stable superhydrophilic wool fabrics is reported here. An ultrathin silica layer coated on the wool altered both the surface roughness and the surface energy of the fiber and endowed the wool fabrics with excellent water absorption. The process of coating silica sols was dependent on an acid solution of low pH, which influenced the electrostatic interactions between nanoparticles and wool fibers. The morphology and composition of silica-sol-coated wool fabrics were characterized by a combination of SEM, TEM, EDX, FTIR, and XPS measurements. The possible mechanism and size effect of silica nanoparticles on the hydrophilic property of wool fabric were discussed. The washing fastness of the superhydrophilic wool fabrics in perchlorethylene and water was also evaluated. This study shows that wool fabrics modified by optical transparence, chemical stability, and nontoxic silica sols are promising in constructing smart textiles. PMID:19908843

  9. One-Dimensional Oxide Nanostructures as Gas-Sensing Materials: Review and Issues

    PubMed Central

    Choi, Kyoung Jin; Jang, Ho Won

    2010-01-01

    In this article, we review gas sensor application of one-dimensional (1D) metal-oxide nanostructures with major emphases on the types of device structure and issues for realizing practical sensors. One of the most important steps in fabricating 1D-nanostructure devices is manipulation and making electrical contacts of the nanostructures. Gas sensors based on individual 1D nanostructure, which were usually fabricated using electron-beam lithography, have been a platform technology for fundamental research. Recently, gas sensors with practical applicability were proposed, which were fabricated with an array of 1D nanostructures using scalable micro-fabrication tools. In the second part of the paper, some critical issues are pointed out including long-term stability, gas selectivity, and room-temperature operation of 1D-nanostructure-based metal-oxide gas sensors. PMID:22319343

  10. Plasmonic nanostructures for bioanalytical applications of SERS

    NASA Astrophysics Data System (ADS)

    Kahraman, Mehmet; Wachsmann-Hogiu, Sebastian

    2016-03-01

    Surface-enhanced Raman scattering (SERS) is a potential analytical technique for the detection and identification of chemicals and biological molecules and structures in the close vicinity of metallic nanostructures. We present a novel method to fabricate tunable plasmonic nanostructures and perform a comprehensive structural and optical characterization of the structures. Spherical latex particles are uniformly deposited on glass slides and used as templates to obtain nanovoid structures on polydimethylsiloxane surfaces. The diameter and depth of the nanovoids are controlled by the size of the latex particles. The nanovoids are coated with a thin Ag layer for fabrication of uniform plasmonic nanostructures. Structural characterization of the surfaces is performed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Optical properties of these plasmonic nanostructures are evaluated via UV/Vis spectroscopy, and SERS. The sample preparation step is the key point to obtain strong and reproducible SERS spectra from the biological structures. When the colloidal suspension is used as a SERS substrate for the protein detection, the electrostatic interaction of the proteins with the nanoparticles is described by the nature of their charge status, which influences the aggregation properties such as the size and shape of the aggregates, which is critical for the SERS experiment. However, when the solid SERS substrates are fabricated, SERS signal of the proteins that are background free and independent of the protein charge. Pros and cons of using plasmonic nano colloids and nanostructures as SERS substrate will be discussed for label-free detection of proteins using SERS.

  11. Artificial frustrated spin systems

    NASA Astrophysics Data System (ADS)

    Perrin, Y.; Chioar, I. A.; Nguyen, V. D.; Lacour, D.; Hehn, M.; Montaigne, F.; Canals, B.; Rougemaille, N.

    2015-09-01

    Complex architectures of nanostructures are routinely elaborated using bottom-up or nanofabrication processes. This technological capability allows scientists to engineer materials with properties that do not exist in nature, but also to manufacture model systems to explore fundamental issues in condensed matter physics. Two-dimensional frustrated arrays of magnetic nanostructures are one class of systems for which theoretical predictions can be tested experimentally. These systems have been the subject of intense research in the last few years and allowed the investigation of a rich physics and fascinating phenomena, such as the exploration of the extensively degenerate ground-state manifolds of spin ice systems, the evidence of new magnetic phases in purely two-dimensional lattices, and the observation of pseudoexcitations involving classical analogues of magnetic monopoles. We show here, experimentally and theoretically, that simple magnetic geometries can lead to unconventional, non-collinear spin textures. For example, kagome arrays of inplane magnetized nano-islands do not show magnetic order. Instead, these systems are characterized by spin textures with intriguing properties, such as chirality, coexistence of magnetic order and disorder, and charge crystallization. Magnetic frustration effects in lithographically patterned kagome arrays of nanomagnets with out-of-plane magnetization also lead to an unusal, and still unknown, magnetic ground state manifold. Besides the influence of the lattice geometry, the micromagnetic nature of the elements constituting the arrays introduce the concept of chiral magnetic monopoles, bringing additional complexity into the physics of artificial frustrated spin systems.

  12. Inorganic nanostructures grown on graphene layers

    NASA Astrophysics Data System (ADS)

    Park, Won Il; Lee, Chul-Ho; Lee, Jung Min; Kim, Nam-Jung; Yi, Gyu-Chul

    2011-09-01

    This article presents a review of current research activities on the hybrid heterostructures of inorganic nanostructures grown directly on graphene layers, which can be categorized primarily as zero-dimensional nanoparticles; one-dimensional nanorods, nanowires, and nanotubes; and two-dimensional nanowalls. For the hybrid structures, the nanostructures exhibit excellent material characteristics including high carrier mobility and radiative recombination rate as well as long-term stability while graphene films show good optical transparency, mechanical flexibility, and electrical conductivity. Accordingly, the versatile and fascinating properties of the nanostructures grown on graphene layers make it possible to fabricate high-performance optoelectronic and electronic devices even in transferable, flexible, or stretchable forms. Here, we review preparation methods and possible device applications of the hybrid structures consisting of various types of inorganic nanostructures grown on graphene layers.

  13. Comparative Incorporation of PNA into DNA Nanostructures.

    PubMed

    Pedersen, Ronnie O; Kong, Jing; Achim, Catalina; LaBean, Thomas H

    2015-01-01

    DNA has shown great promise as a building material for self-assembling nanoscale structures. To further develop the potential of this technology, more methods are needed for functionalizing DNA-based nanostructures to increase their chemical diversity. Peptide nucleic acid (PNA) holds great promise for realizing this goal, as it conveniently allows for inclusion of both amino acids and peptides in nucleic acid-based structures. In this work, we explored incorporation of a positively charged PNA within DNA nanostructures. We investigated the efficiency of annealing a lysine-containing PNA probe with complementary, single-stranded DNA sequences within nanostructures, as well as the efficiency of duplex invasion and its dependence on salt concentration. Our results show that PNA allows for toehold-free strand displacement and that incorporation yield depends critically on binding site geometry. These results provide guidance for the design of PNA binding sites on nucleic acid nanostructures with an eye towards optimizing fabrication yield. PMID:26404232

  14. Terahertz Artificial Dielectric Lens

    NASA Astrophysics Data System (ADS)

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-03-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices.

  15. Terahertz Artificial Dielectric Lens

    PubMed Central

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M.

    2016-01-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices. PMID:26973294

  16. Terahertz Artificial Dielectric Lens.

    PubMed

    Mendis, Rajind; Nagai, Masaya; Wang, Yiqiu; Karl, Nicholas; Mittleman, Daniel M

    2016-01-01

    We have designed, fabricated, and experimentally characterized a lens for the THz regime based on artificial dielectrics. These are man-made media that mimic properties of naturally occurring dielectric media, or even manifest properties that cannot generally occur in nature. For example, the well-known dielectric property, the refractive index, which usually has a value greater than unity, can have a value less than unity in an artificial dielectric. For our lens, the artificial-dielectric medium is made up of a parallel stack of 100 μm thick metal plates that form an array of parallel-plate waveguides. The convergent lens has a plano-concave geometry, in contrast to conventional dielectric lenses. Our results demonstrate that this lens is capable of focusing a 2 cm diameter beam to a spot size of 4 mm, at the design frequency of 0.17 THz. The results further demonstrate that the overall power transmission of the lens can be better than certain conventional dielectric lenses commonly used in the THz regime. Intriguingly, we also observe that under certain conditions, the lens boundary demarcated by the discontinuous plate edges actually resembles a smooth continuous surface. These results highlight the importance of this artificial-dielectric technology for the development of future THz-wave devices. PMID:26973294

  17. Artificial noses.

    PubMed

    Stitzel, Shannon E; Aernecke, Matthew J; Walt, David R

    2011-08-15

    The mammalian olfactory system is able to detect many more odorants than the number of receptors it has by utilizing cross-reactive odorant receptors that generate unique response patterns for each odorant. Mimicking the mammalian system, artificial noses combine cross-reactive sensor arrays with pattern recognition algorithms to create robust odor-discrimination systems. The first artificial nose reported in 1982 utilized a tin-oxide sensor array. Since then, however, a wide range of sensor technologies have been developed and commercialized. This review highlights the most commonly employed sensor types in artificial noses: electrical, gravimetric, and optical sensors. The applications of nose systems are also reviewed, covering areas such as food and beverage quality control, chemical warfare agent detection, and medical diagnostics. A brief discussion of future trends for the technology is also provided. PMID:21417721

  18. Photoinduced magnetic force between nanostructures

    NASA Astrophysics Data System (ADS)

    Guclu, Caner; Tamma, Venkata Ananth; Wickramasinghe, Hemantha Kumar; Capolino, Filippo

    2015-12-01

    Photoinduced magnetic force between nanostructures, at optical frequencies, is investigated theoretically. Till now optical magnetic effects were not used in scanning probe microscopy because of the vanishing natural magnetism with increasing frequency. On the other hand, artificial magnetism in engineered nanostructures led to the development of measurable optical magnetism. Here two examples of nanoprobes that are able to generate strong magnetic dipolar fields at optical frequency are investigated: first, an ideal magnetically polarizable nanosphere and then a circular cluster of silver nanospheres that has a looplike collective plasmonic resonance equivalent to a magnetic dipole. Magnetic forces are evaluated based on nanostructure polarizabilities, i.e., induced magnetic dipoles, and magnetic-near field evaluations. As an initial assessment on the possibility of a magnetic nanoprobe to detect magnetic forces, we consider two identical magnetically polarizable nanoprobes and observe magnetic forces on the order of piconewtons, thereby bringing it within detection limits of conventional atomic force microscopes at ambient pressure and temperature. The detection of magnetic force is a promising method in studying optical magnetic transitions that can be the basis of innovative spectroscopy applications.

  19. Magnetron sputtering in the creation of photonic nanostructures derived from Sasakia Charonda Formosana-butterfly wings for applied in dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Niu, Haihong; Zhou, Ru; Cheng, Cong; Zhang, Gonghai; Hu, Yu; Huang, Bin; Zhang, Shouwei; Shang, Xin; Xia, Mei; Xu, Jinzhang

    2016-09-01

    Creating new functional materials derived from the structures seen on butterfly wings has achieved interest in a variety of research topics. However, there need a concision approach could result in a high-quality, precise, and convenient process for the fabrication of complex nanostructures replication with unique functionalities based on the butterfly wings. Here we developed a pithy approach based on a magnetron sputtering metal Ti process for biotemplating used to refine hierarchically porous titanium dioxide photonic crystal nanostructures (TiO2sbnd PCN), themselves derived from nanostructures present on the wings of Sasakia Charonda Formosana (S. Charonda) butterflies. For the first time, the TiO2sbnd PCN were deposited on the top of the P25 active layer and were used to fabricate DSSCs as the light-scattering layers of photoanodes with power conversion efficiencies of up to 8.7%. Remarkably, a much enhanced photocurrent density and a prominent photoelectrochemical conversion capability have been achieved, which are exceeding most of the previously reported photoanodes as well as a similar butterflies replication-based device structure. Our study suggests many exciting opportunities of developing artificially engineered butterfly wing-based solar-to-fuel conversion.

  20. Geometrically induced surface polaritons in planar nanostructured metallic cavities

    SciTech Connect

    Davids, P. S.; Intravia, F; Dalvit, Diego A.

    2014-01-14

    We examine the modal structure and dispersion of periodically nanostructured planar metallic cavities within the scattering matrix formulation. By nanostructuring a metallic grating in a planar cavity, artificial surface excitations or spoof plasmon modes are induced with dispersion determined by the periodicity and geometric characteristics of the grating. These spoof surface plasmon modes are shown to give rise to new cavity polaritonic modes at short mirror separations that modify the density of modes in nanostructured cavities. The increased modal density of states form cavity polarirons have a large impact on the fluctuation induced electromagnetic forces and enhanced hear transfer at short separations.

  1. Artificial Intelligence.

    ERIC Educational Resources Information Center

    Wash, Darrel Patrick

    1989-01-01

    Making a machine seem intelligent is not easy. As a consequence, demand has been rising for computer professionals skilled in artificial intelligence and is likely to continue to go up. These workers develop expert systems and solve the mysteries of machine vision, natural language processing, and neural networks. (Editor)

  2. Facile Synthesis of Three-Dimensional ZnO Nanostructure: Realization of a Multifunctional Stable Superhydrophobic Surface

    PubMed Central

    Wu, Jun; Xia, Jun; Lei, Wei; Wang, Baoping

    2011-01-01

    Background After comprehensive study of various superhydrophobic phenomena in nature, it is no longer a puzzle for researchers to realize such fetching surfaces. However, the different types of artificial surfaces may get wetted and lose its water repellence if there exist defects or the liquid is under pressure. With respect to the industry applications, in which the resistance of wetting transition is critical important, new nanostructure satisfied a certain geometric criterion should be designed to hold a stable gas film at the base area to avoid the wet transition. Methodology A thermal deposition method was utilized to produce a thin ZnO seeds membrane on the aluminum foil. And then a chemical self-assemble technology was developed in present work to fabricate three-dimensional (3D) hierarchical dune-like ZnO architecture based on the prepared seeds membrane. Results Hierarchical ZnO with micro scale dune-like structure and core-sharing nanosheets was generated. The characterization results showed that there exist plenty of gaps and interfaces among the micro-dune and nanosheets, and thus the surface area was enlarged by such a unique morphology. Benefited from this unique 3D ZnO hierarchical nanostructure, the obtained surface exhibited stable water repellency after modification with Teflon, and furthermore, based on solid theory analysis, such 3D ZnO nanostructure would exhibit excellent sensing performance. PMID:22194987

  3. Nanostructured Inverted Organic Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Thomas, Michael

    Organic photovoltaic cells (OPVs)are promising devices for inexpensive power generation from sunlight. Organic semiconductors, the basic materials for OPVs, can be fabricated using a broad range of fabrication technologies from vapor deposition to solution processing. Upon light absorption, a strongly bound exciton is generated which can diffuse to a donor-acceptor heterojunction. At this interface it can be dissociated into free charge carriers which can be collected by the device electrodes. A major challenge for OPVs are short exciton diffusion lengths of up to 20 nm. Morphology engineering is required in order to harvest the exciton before it recombines and improve OPV performance. This work focuses on the study of nanostructured morphologies for use in inverted architecture OPVs. Glancing angle deposition (GLAD)is employed to fabricate nanocolumnar acceptor films. Through combining these nanostructured C60 films with a conjugated polymer donor P3CBT and a small molecule 3-Q, inverted OPVs are fabricated with the goal to analyze effect of morphology engineering on device performance. A major challenge was that C60 were found to be soluble in most commonly used organic solvents such as dichlorobenzene or chloroform. Although this challenge has limited the donor choice and therefore has limited device performance, a significant effect of morphology engineering could be observed. All GLAD structured C60 OPVs outperformed state of the art architectures such as planar films and bulk heterojunctions fabricated with the same materials. For P3CBT in particular the GLAD structured devices exhibited a twofold increase in power conversion efficiency compared with bulk heterojunctions and a fourfold increase compared with planar devices. In a further study, the acceptor materials PTCDA and C60 were co-evaporated into a single film. PTCDA is stable against non-polar organic solvents while C60 provides a high electron mobility. Nanocolumnar acceptor blended PTCDA:C60 films

  4. Introduction of Artificial Pinning Center into PLD-YBCO Coated Conductor on IBAD and Self-Epitaxial CeO2 Buffered Metal Substrate

    SciTech Connect

    Kobayashi, H.; Yamada, Y.; Ishida, S.; Takahashi, K.; Konishi, M.; Ibi, A.; Miyata, S.; Kato, T.; Hirayama, T.; Shiohara, Y.

    2006-03-31

    In order to fabricate YBa2Cu3O7-x (YBCO) coated conductors with high critical current density Jc in magnetic fields, we fabricated YBCO coated conductors with artificial pinning centers by the pulsed laser deposition (PLD) method on a self epitaxial PLD-CeO2 layer and ion-beam assisted deposition (IBAD)-Gd2Zr2O7 (GZO) buffered Hastelloy tape. Artificial pinning centers were introduced by the PLD deposition using the yttria-stabilized zirconia (YSZ) oxide target (nano-dot method) and YBCO target including YSZ particles (mixed target method). In the experiments using YSZ oxide target, YSZ nano-dots were observed. They were approximately 15 nm in height and 10 nm to 70 nm in diameter. We found that the density of nano-dots was controlled by the number of laser pulses. These samples exhibited higher Jc than YBCO films in magnetic fields. Furthermore, a similar improvement of Jc was observed in the experiments using YBCO target including YSZ particles. TEM observation revealed that columnar nano-structure made of BaZrO3 was formed during YBCO deposition and it was effective for pinning. We call this new epitaxial nano-structure 'bamboo structure' from its anisotropic growth and morphology.

  5. Fabrication and characterization of ZnO@CdS core-shell nanostructure using acetate precursors: XRD, FESEM, DRS, FTIR studies and effects of cadmium ion concentration on band gap

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad Hossein; Rahmati, Mohammad Hossein

    2014-12-01

    ZnO@CdS core-shell nano-structure has been synthesized using zinc acetate dihydrate, and cadmium acetate dihydrate as simple precursors in a water-ethanol matrix without using any surfactant, ligand or chelating agents. The effect of different concentrations of cadmium acetate and sodium sulfide on optical and electronic properties of ZnO@CdS core-shell was investigated. The morphology and structure of the ZnO@CdS core-shell nano-structures have been confirmed by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) measurements. The results showed that the ZnO@CdS core-shell nano-structure is mixed cubic and hexagonal structures. FESEM results showed the mono-dispersed and uniform size of 39 nm. Optical properties were studied by UV-visible diffuse reflectance spectroscopy (DRS) technique and the results showed that band gaps of ZnO@CdS core-shell nanocomposites were red shifted by increasing the cadmium concentration. FTIR spectrum of ZnO@CdS core-shell nano-structure showed a band at 482 cm-1 correlated to Znsbnd O bond and a band at 630 cm-1 due to the stretching frequency of Cdsbnd S bond.

  6. Plasmonic spectroscopy of metallic nanostructures

    NASA Astrophysics Data System (ADS)

    Ni, Weihai

    gap distance between assembled nanorods. Moreover, dye--Au nanorod hybrid nanostructures have also been successfully fabricated for the study of the coupling between the transition dipole resonance and the plasmonic resonance. The coupling-induced plasmon shift is found to be strongly dependent on molecular properties, the dye concentration in solutions, and the spacer thickness between dye molecules and the surface of Au nanorods. The coupling can be switched off by means of laser-induced photodecomposition of dye molecules. Next, I will present my studies on the applications of metallic nanostructures. A SERS substrate has been constructed by assembling silver nanoparticles along silica nanofibers. The enhancement factors are found to be 2 x 10 5 for 4-mercaptobenzoic acid and 4-mercaptophenol, and 7 x 10 7 for rhodamine B isothiocyanate. A novel plasmonic optical fiber device has further been fabricated to detect small changes in the local dielectric environment. For individual Au nanorods, the index sensitivity and figure of merit (FOM) are found to be linearly dependent on the longitudinal plasmon resonance wavelength and reach 200 nm/RIU and 3.8, respectively. For nanorod ensembles, the index sensitivity and FOM of the longitudinal plasmon resonance are found to be 138 nm/RIU and 1.2, respectively. I believe that my research work on the plasmonic spectroscopy of metallic nanostructures has provided an in-depth fundamental understanding of the localized surface plasmon resonance and will have a number of implications for the applications of metallic nanostructures in optics, optoelectronics, and biotechnology.

  7. Engineering Hybrid Metallic Nanostructures Using a Single Domain of Block Copolymer Templates.

    PubMed

    Liu, Zhicheng; Chang, Tongxin; Huang, Haiying; He, Tianbai

    2015-11-25

    Building complex nanostructures using a simple patterned template is challenging in material science and nanotechnology. In the present work, three different strategies have been exploited for the successful fabrication of hybrid dots-on-wire metallic nanostructures through combining an in-situ method with an ex-situ method. Basically, plasma etching was applied to generate a metallic wire-like nanostructure, and preformed nanoparticles could be placed through multiple means before or after the formation of the wire-like nanostructure. Various monometallic and bimetallic nanostructures have been obtained by utilizing only one functional domain of block copolymer templates. In these cases, full utilization of the functional domain or introduction of the molecular linker is critical to engineering hybrid metallic nanostructures. Other complex and multifunctional hybrid nanostructures can be developed via these strategies similarly, and these nanostructures are promising for useful applications such as optics and surface-enhanced Raman spectroscopy (SERS). PMID:26517409

  8. Artificial Intelligence.

    PubMed

    Lawrence, David R; Palacios-González, César; Harris, John

    2016-04-01

    It seems natural to think that the same prudential and ethical reasons for mutual respect and tolerance that one has vis-à-vis other human persons would hold toward newly encountered paradigmatic but nonhuman biological persons. One also tends to think that they would have similar reasons for treating we humans as creatures that count morally in our own right. This line of thought transcends biological boundaries-namely, with regard to artificially (super)intelligent persons-but is this a safe assumption? The issue concerns ultimate moral significance: the significance possessed by human persons, persons from other planets, and hypothetical nonorganic persons in the form of artificial intelligence (AI). This article investigates why our possible relations to AI persons could be more complicated than they first might appear, given that they might possess a radically different nature to us, to the point that civilized or peaceful coexistence in a determinate geographical space could be impossible to achieve. PMID:26957450

  9. Electron-electron interactions in artificial graphene.

    PubMed

    Räsänen, E; Rozzi, C A; Pittalis, S; Vignale, G

    2012-06-15

    Recent advances in the creation and modulation of graphenelike systems are introducing a science of "designer Dirac materials". In its original definition, artificial graphene is a man-made nanostructure that consists of identical potential wells (quantum dots) arranged in an adjustable honeycomb lattice in the two-dimensional electron gas. As our ability to control the quality of artificial graphene samples improves, so grows the need for an accurate theory of its electronic properties, including the effects of electron-electron interactions. Here we determine those effects on the band structure and on the emergence of Dirac points. PMID:23004308

  10. Electron-electron interactions in artificial graphene

    NASA Astrophysics Data System (ADS)

    Rasanen, Esa

    2013-03-01

    Recent advances in the creation and modulation of graphenelike systems are introducing a science of ``designer Dirac materials.'' In its original definition, artificial graphene is a man-made nanostructure that consists of identical potential wells (quantum dots) arranged in an adjustable honeycomb lattice in the two-dimensional electron gas. As our ability to control the quality of artificial graphene samples improves, so grows the need for an accurate theory of its electronic properties, including the effects of electron-electron interactions. Here we determine those effects on the band structure and on the emergence of Dirac points, and discuss future investigations and challenges in this field.

  11. Electron-Electron Interactions in Artificial Graphene

    NASA Astrophysics Data System (ADS)

    Räsänen, E.; Rozzi, C. A.; Pittalis, S.; Vignale, G.

    2012-06-01

    Recent advances in the creation and modulation of graphenelike systems are introducing a science of “designer Dirac materials”. In its original definition, artificial graphene is a man-made nanostructure that consists of identical potential wells (quantum dots) arranged in an adjustable honeycomb lattice in the two-dimensional electron gas. As our ability to control the quality of artificial graphene samples improves, so grows the need for an accurate theory of its electronic properties, including the effects of electron-electron interactions. Here we determine those effects on the band structure and on the emergence of Dirac points.

  12. Biomimicry of multifunctional nanostructures in the neck feathers of mallard (Anas platyrhynchos L.) drakes.

    PubMed

    Khudiyev, Tural; Dogan, Tamer; Bayindir, Mehmet

    2014-01-01

    Biological systems serve as fundamental sources of inspiration for the development of artificially colored devices, and their investigation provides a great number of photonic design opportunities. While several successful biomimetic designs have been detailed in the literature, conventional fabrication techniques nonetheless remain inferior to their natural counterparts in complexity, ease of production and material economy. Here, we investigate the iridescent neck feathers of Anas platyrhynchos drakes, show that they feature an unusual arrangement of two-dimensional (2D) photonic crystals and further exhibit a superhydrophobic surface, and mimic this multifunctional structure using a nanostructure composite fabricated by a recently developed top-down iterative size reduction method, which avoids the above-mentioned fabrication challenges, provides macroscale control and enhances hydrophobicity through the surface structure. Our 2D solid core photonic crystal fibres strongly resemble drake neck plumage in structure and fully polymeric material composition, and can be produced in wide array of colors by minor alterations during the size reduction process. PMID:24751587

  13. Biomimicry of multifunctional nanostructures in the neck feathers of mallard (Anas platyrhynchos L.) drakes

    PubMed Central

    Khudiyev, Tural; Dogan, Tamer; Bayindir, Mehmet

    2014-01-01

    Biological systems serve as fundamental sources of inspiration for the development of artificially colored devices, and their investigation provides a great number of photonic design opportunities. While several successful biomimetic designs have been detailed in the literature, conventional fabrication techniques nonetheless remain inferior to their natural counterparts in complexity, ease of production and material economy. Here, we investigate the iridescent neck feathers of Anas platyrhynchos drakes, show that they feature an unusual arrangement of two-dimensional (2D) photonic crystals and further exhibit a superhydrophobic surface, and mimic this multifunctional structure using a nanostructure composite fabricated by a recently developed top-down iterative size reduction method, which avoids the above-mentioned fabrication challenges, provides macroscale control and enhances hydrophobicity through the surface structure. Our 2D solid core photonic crystal fibres strongly resemble drake neck plumage in structure and fully polymeric material composition, and can be produced in wide array of colors by minor alterations during the size reduction process. PMID:24751587

  14. Process Development for Nanostructured Photovoltaics

    SciTech Connect

    Elam, Jeffrey W.

    2015-01-01

    Photovoltaic manufacturing is an emerging industry that promises a carbon-free, nearly limitless source of energy for our nation. However, the high-temperature manufacturing processes used for conventional silicon-based photovoltaics are extremely energy-intensive and expensive. This high cost imposes a critical barrier to the widespread implementation of photovoltaic technology. Argonne National Laboratory and its partners recently invented new methods for manufacturing nanostructured photovoltaic devices that allow dramatic savings in materials, process energy, and cost. These methods are based on atomic layer deposition, a thin film synthesis technique that has been commercialized for the mass production of semiconductor microelectronics. The goal of this project was to develop these low-cost fabrication methods for the high efficiency production of nanostructured photovoltaics, and to demonstrate these methods in solar cell manufacturing. We achieved this goal in two ways: 1) we demonstrated the benefits of these coatings in the laboratory by scaling-up the fabrication of low-cost dye sensitized solar cells; 2) we used our coating technology to reduce the manufacturing cost of solar cells under development by our industrial partners.

  15. Enhanced structural stability of DNA origami nanostructures by graphene encapsulation

    NASA Astrophysics Data System (ADS)

    Matković, Aleksandar; Vasić, Borislav; Pešić, Jelena; Prinz, Julia; Bald, Ilko; Milosavljević, Aleksandar R.; Gajić, Radoš

    2016-02-01

    We demonstrate that a single-layer graphene replicates the shape of DNA origami nanostructures very well. It can be employed as a protective layer for the enhancement of structural stability of DNA origami nanostructures. Using the AFM based manipulation, we show that the normal force required to damage graphene encapsulated DNA origami nanostructures is over an order of magnitude greater than for the unprotected ones. In addition, we show that graphene encapsulation offers protection to the DNA origami nanostructures against prolonged exposure to deionized water, and multiple immersions. Through these results we demonstrate that graphene encapsulated DNA origami nanostructures are strong enough to sustain various solution phase processing, lithography and transfer steps, thus extending the limits of DNA-mediated bottom-up fabrication.

  16. Artificial halos

    NASA Astrophysics Data System (ADS)

    Selmke, Markus

    2015-09-01

    Judged by their frequency and beauty, ice halos easily rival rainbows as a prominent atmospheric optics phenomenon. This article presents experimental halo demonstrations of varying complexity. Using a single commercially available hexagonal glass prism, a variety of artificial halos can be simulated. The experiments include laser beam path analysis, a modified classic spinning prism experiment, and a novel Monte-Carlo machine for three-dimensional rotations. Each of these experiments emulates different conditions of certain halo displays, and in combination, they allow a thorough understanding of these striking phenomena.

  17. Tuning and synthesis of metallic nanostructures by mechanical compression

    DOEpatents

    Fan, Hongyou; Li, Binsong

    2015-11-17

    The present invention provides a pressure-induced phase transformation process to engineer metal nanoparticle architectures and to fabricate new nanostructured materials. The reversible changes of the nanoparticle unit cell dimension under pressure allow precise control over interparticle separation in 2D or 3D nanoparticle assemblies, offering unique robustness for interrogation of both quantum and classic coupling interactions. Irreversible changes above a threshold pressure of about 8 GPa enables new nanostructures, such as nanorods, nanowires, or nanosheets.

  18. Highly integrated synthesis of heterogeneous nanostructures on nanowire heater array

    NASA Astrophysics Data System (ADS)

    Jin, Chun Yan; Yun, Jeonghoon; Kim, Jung; Yang, Daejong; Kim, Dong Hwan; Ahn, Jae Hyuk; Lee, Kwang-Cheol; Park, Inkyu

    2014-11-01

    We have proposed a new method for the multiplexed synthesis of heterogeneous nanostructures using a top-down fabricated nanowire heater array. Hydrothermally synthesized nanostructures can be grown only on the heated nanowire through nanoscale temperature control using a Joule heated nanowire. We have demonstrated the selective synthesis of zinc oxide (ZnO) nanowires and copper oxide (CuO) nanostructures, as well as their surface modification with noble metal nanoparticles, using a nanowire heater array. Furthermore, we could fabricate an array of heterogeneous nanostructures via Joule heating of individual nanowire heaters and changing of the precursor solutions in a sequential manner. We have formed a parallel array of palladium (Pd) coated ZnO nanowires and gold (Au) coated ZnO nanowires, as well as a parallel array of ZnO nanowires and CuO nanospikes, in the microscale region by using the developed method.We have proposed a new method for the multiplexed synthesis of heterogeneous nanostructures using a top-down fabricated nanowire heater array. Hydrothermally synthesized nanostructures can be grown only on the heated nanowire through nanoscale temperature control using a Joule heated nanowire. We have demonstrated the selective synthesis of zinc oxide (ZnO) nanowires and copper oxide (CuO) nanostructures, as well as their surface modification with noble metal nanoparticles, using a nanowire heater array. Furthermore, we could fabricate an array of heterogeneous nanostructures via Joule heating of individual nanowire heaters and changing of the precursor solutions in a sequential manner. We have formed a parallel array of palladium (Pd) coated ZnO nanowires and gold (Au) coated ZnO nanowires, as well as a parallel array of ZnO nanowires and CuO nanospikes, in the microscale region by using the developed method. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04216f

  19. A nanostructured electrochromic supercapacitor.

    PubMed

    Wei, Di; Scherer, Maik R J; Bower, Chris; Andrew, Piers; Ryhänen, Tapani; Steiner, Ullrich

    2012-04-11

    We report the first successful application of an ordered bicontinuous double-gyroid vanadium pentoxide network in an electrochromic supercapacitor. The freestanding vanadia network was fabricated by electrodeposition into a voided block copolymer template that had self-assembled into the double-gyroid morphology. The highly ordered structure with 11.0 nm wide struts and a high specific surface to bulk volume ratio of 161.4 μm(-1) is ideal for fast and efficient lithium ion intercalation/extraction and faradaic surface reactions, which are essential for high energy and high power density electrochemical energy storage devices. Supercapacitors made from such gyroid-structured vanadia electrodes exhibit a high specific capacitance of 155 F g(-1) and show a strong electrochromic color change from green/gray to yellow, indicating the capacitor's charge condition. The nanostructuring approach and utilizing an electrode material that has intrinsic electrochemical color-change properties are concepts that can be readily extended to other electrochromic intercalation compounds. PMID:22390702

  20. Probing electronic transport of individual nanostructures with atomic precision

    SciTech Connect

    Qin, Shengyong; Li, An-Ping

    2012-01-01

    Accessing individual nanostructures with atomic precision is an important process in the bottom-up fabrication and characterization of electronic nanodevices. Local electrical contacts, namely nanoelectrodes, are often fabricated by using top-down lithography and chemical etching techniques. These processes however lack atomic precision and introduce the possibility of contamination. Here, we review recent reports on the application of a field-induced emission process in the fabrication of local contacts onto individual nanowires and nanotubes with atomic spatial precision. In this method, gold nanoislands are deposited onto nanostructures precisely by using a scanning tunneling microscope tip, which provides a clean and controllable process to ensure both electrically conductive and mechanically reliable contacts. The applicability of the technique has been demonstrated in a wide variety of nanostructures, including silicide atomic wires, carbon nanotubes, and copper nanowires. These local contacts bridge the nanostructures and the transport probes, allowing for the measurements of both electrical transport and scanning tunneling microscopy on the same nanostructures in situ. The direct correlation between electronic and transport properties and atomic structures can be explored on individual nanostructures at the unprecedented atomic level.

  1. Enhancement of antireflection property of silicon using nanostructured surface combined with a polymer deposition.

    PubMed

    Ha, Jun Mok; Yoo, Sung Ho; Cho, Jong Hoi; Cho, Yong Hoon; Cho, Sung Oh

    2014-01-01

    Silicon (Si) nanostructures that exhibit a significantly low reflectance in ultraviolet (UV) and visible light wavelength regions are fabricated using a hydrogen etching process. The fabricated Si nanostructures have aperiodic subwavelength structures with pyramid-like morphologies. The detailed morphologies of the nanostructures can be controlled by changing the etching condition. The nanostructured Si exhibited much more reduced reflectance than a flat Si surface: an average reflectance of the nanostructured Si was approximately 6.8% in visible light region and a slight high reflectance of approximately 17% in UV region. The reflectance was further reduced in both UV and visible light region through the deposition of a poly(dimethylsiloxane) layer with a rough surface on the Si nanostructure: the reflectance can be decreased down to 2.5%. The enhancement of the antireflection properties was analyzed with a finite difference time domain simulation method. PMID:24397945

  2. Periodic nanostructures for tunable thin optics

    NASA Astrophysics Data System (ADS)

    Criante, L.; Di Fonzo, F.; Fumagalli, F.; Lanzani, G.; Passoni, L.; Scotognella, F.; Simoni, F.

    2015-08-01

    We report the realization and characterization of porous nanostructures where a periodic refractive index modulation is achieved by stacking layers with different nano-architectures. One multilayer photonic crystal has been fabricated starting from colloidal dispersion of silicon dioxide and zirconium dioxide using spin coating technique. Improved efficiency of Bragg reflectivity (up to 85%) has been obtained by a new bottom-up fabrication technique of photonic hierarchical nanostructures based on self-assembly from the gas-phase at low temperature whit a very thin (≍ 1 μm) photonic crystal devices. Due to the high porosity, these systems can be infiltrated with nematic liquid crystals leading to tuning of the Bragg reflection band by applying low voltages to the structure.

  3. Magnetically Responsive Nanostructures with Tunable Optical Properties.

    PubMed

    Wang, Mingsheng; Yin, Yadong

    2016-05-25

    Stimuli-responsive materials can sense specific environmental changes and adjust their physical properties in a predictable manner, making them highly desired components for designing novel sensors, intelligent systems, and adaptive structures. Magnetically responsive structures have unique advantages in applications, as external magnetic stimuli can be applied in a contactless manner and cause rapid and reversible responses. In this Perspective, we discuss our recent progress in the design and fabrication of nanostructured materials with various optical responses to externally applied magnetic fields. We demonstrate tuning of the optical properties by taking advantage of the magnetic fields' abilities to induce magnetic dipole-dipole interactions or control the orientation of the colloidal magnetic nanostructures. The design strategies are expected to be extendable to the fabrication of novel responsive materials with new optical effects and many other physical properties. PMID:27115174

  4. Towards in vitro molecular diagnostics using nanostructures.

    PubMed

    Kurkina, Tetiana; Balasubramanian, Kannan

    2012-02-01

    Nanostructures appear to be promising for a number of applications in molecular diagnostics, mainly due to the increased surface-to-volume ratio they can offer, the very low limit of detection achievable, and the possibility to fabricate point-of-care diagnostic devices. In this paper, we review examples of the use of nanostructures as diagnostic tools that bring in marked improvements over prevalent classical assays. The focus is laid on the various sensing paradigms that possess the potential or have demonstrated the capability to replace or augment current analytical strategies. We start with a brief introduction of the various types of nanostructures and their physical properties that determine the transduction principle. This is followed by a concise collection of various functionalization protocols used to immobilize biomolecules on the nanostructure surface. The sensing paradigms are discussed in two contexts: the nanostructure acting as a label for detection, or the nanostructure acting as a support upon which the molecular recognition events take place. In order to be successful in the field of molecular diagnostics, it is important that the nanoanalytical tools be evaluated in the appropriate biological environment. The final section of the review compiles such examples, where the nanostructure-based diagnostic tools have been tested on realistic samples such as serum, demonstrating their analytical power even in the presence of complex matrix effects. The ability of nanodiagnostic tools to detect ultralow concentrations of one or more analytes coupled with portability and the use of low sample volumes is expected to have a broad impact in the field of molecular diagnostics. PMID:22009454

  5. Facile fabrication of silver nanofin array via electroless plating.

    PubMed

    Miyoshi, Kentaro; Aoki, Yoshitaka; Kunitake, Toyoki; Fujikawa, Shigenori

    2008-04-15

    The fabrication of metallic nanostructures is one of the main issues in nanotechnology. This article describes the fabrication of a silver nanofin array by combining microlithography, electroless plating, and an etching technique. Fabricated Ag nanofins have a high aspect ratio (height/width = 10, width = 60 nm, height = 600 nm), and their widths and heights can be controlled by the period of electroless plating and the height of the original line pattern. An isolated Ag nanofin was proven to show metallic electrical conductivity. The current process provides a rapid and shape-designable fabrication method of metallic nanostructures. PMID:18312009

  6. INTERSTELLAR ANALOGS FROM DEFECTIVE CARBON NANOSTRUCTURES ACCOUNT FOR INTERSTELLAR EXTINCTION

    SciTech Connect

    Tan, Zhenquan; Abe, Hiroya; Sato, Kazuyoshi; Ohara, Satoshi; Chihara, Hiroki; Koike, Chiyoe; Kaneko, Kenji

    2010-11-15

    Because interstellar dust is closely related to the evolution of matter in the galactic environment and many other astrophysical phenomena, the laboratory synthesis of interstellar dust analogs has received significant attention over the past decade. To simulate the ultraviolet (UV) interstellar extinction feature at 217.5 nm originating from carbonaceous interstellar dust, many reports focused on the UV absorption properties of laboratory-synthesized interstellar dust analogs. However, no general relation has been established between UV interstellar extinction and artificial interstellar dust analogs. Here, we show that defective carbon nanostructures prepared by high-energy collisions exhibit a UV absorption feature at 220 nm which we suggest accounts for the UV interstellar extinction at 217.5 nm. The morphology of some carbon nanostructures is similar to that of nanocarbons discovered in the Allende meteorite. The similarity between the absorption feature of the defective carbon nanostructures and UV interstellar extinction indicates a strong correlation between the defective carbon nanostructures and interstellar dust.

  7. Synthesis of different copper nanostructures by the use of polyol technique

    NASA Astrophysics Data System (ADS)

    Hosseini, Maryamsadat; Fatmehsari, Davoud Haghshenas; Marashi, Seyed Pirooz Hoveida

    2015-09-01

    Self-seeding polyol synthesis method, without additives, was employed for the fabrication of different copper nanostructures. The pertinent parameters including temperature, copper concentration and molar ratio of poly(vinylpyrrolidone) (PVP) to copper were assessed for achieving different size and morphology of copper nanostructures, i.e., nanowire, nanosphere and nanocube. It was found that PVP-to-copper molar ratio has the most significant effect on the geometry of the copper nanostructures.

  8. Nanostructured ion beam-modified Ge films for high capacity Li ion battery anodes

    SciTech Connect

    Rudawski, N. G.; Darby, B. L.; Yates, B. R.; Jones, K. S.; Elliman, R. G.; Volinsky, A. A.

    2012-02-20

    Nanostructured ion beam-modified Ge electrodes fabricated directly on Ni current collector substrates were found to exhibit excellent specific capacities during electrochemical cycling in half-cell configuration with Li metal for a wide range of cycling rates. Structural characterization revealed that the nanostructured electrodes lose porosity during cycling but maintain excellent electrical contact with the metallic current collector substrate. These results suggest that nanostructured Ge electrodes have great promise for use as high performance Li ion battery anodes.

  9. Artificial multilayers and nanomagnetic materials

    PubMed Central

    SHINJO, Teruya

    2013-01-01

    The author has been actively engaged in research on nanomagnetic materials for about 50 years. Nanomagnetic materials are comprised of ferromagnetic systems for which the size and shape are controlled on a nanometer scale. Typical examples are ultrafine particles, ultrathin films, multilayered films and nano-patterned films. In this article, the following four areas of the author’s studies are described. (1) Mössbauer spectroscopic studies of nanomagnetic materials and interface magnetism. (2) Preparation and characterization of metallic multilayers with artificial superstructures. (3) Giant magnetoresistance (GMR) effect in magnetic multilayers. (4) Novel properties of nanostructured ferromagnetic thin films (dots and wires). A subject of particular interest in the author’s research was the artificially prepared multilayers consisting of metallic elements. The motivation to initiate the multilayer investigation is described and the physical properties observed in the artificial multilayers are introduced. The author’s research was initially in the field of pure physical science and gradually extended into applied science. His achievements are highly regarded not only from the fundamental point of view but also from the technological viewpoint. PMID:23391605

  10. Artificial Hydrogenases

    PubMed Central

    Barton, Bryan E.; Olsen, Matthew T.; Rauchfuss, Thomas B.

    2010-01-01

    Decades of biophysical study on the hydrogenase (H2ase) enzymes have yielded sufficient information to guide the synthesis of analogues of their active sites. Three families of enzymes serve as inspiration for this work: the [FeFe]-, [NiFe]-, and [Fe]-H2ases, all of which feature iron centers bound to both CO and thiolate. Artificial H2ases effect the oxidation of H2 of H2 and the reverse reaction, the reduction of protons. These reactions occur via the intermediacy of metal hydrides. The inclusion of amine bases within the catalysts is an important design feature that is emulated in related bioinspired catalysts. Continuing challenges are the low reactivity of H2 towards biomimetic H2ases. PMID:20356731

  11. Artificial rheotaxis

    PubMed Central

    Palacci, Jérémie; Sacanna, Stefano; Abramian, Anaïs; Barral, Jérémie; Hanson, Kasey; Grosberg, Alexander Y.; Pine, David J.; Chaikin, Paul M.

    2015-01-01

    Motility is a basic feature of living microorganisms, and how it works is often determined by environmental cues. Recent efforts have focused on developing artificial systems that can mimic microorganisms, in particular their self-propulsion. We report on the design and characterization of synthetic self-propelled particles that migrate upstream, known as positive rheotaxis. This phenomenon results from a purely physical mechanism involving the interplay between the polarity of the particles and their alignment by a viscous torque. We show quantitative agreement between experimental data and a simple model of an overdamped Brownian pendulum. The model notably predicts the existence of a stagnation point in a diverging flow. We take advantage of this property to demonstrate that our active particles can sense and predictably organize in an imposed flow. Our colloidal system represents an important step toward the realization of biomimetic microsystems with the ability to sense and respond to environmental changes. PMID:26601175

  12. Artificial rheotaxis.

    PubMed

    Palacci, Jérémie; Sacanna, Stefano; Abramian, Anaïs; Barral, Jérémie; Hanson, Kasey; Grosberg, Alexander Y; Pine, David J; Chaikin, Paul M

    2015-05-01

    Motility is a basic feature of living microorganisms, and how it works is often determined by environmental cues. Recent efforts have focused on developing artificial systems that can mimic microorganisms, in particular their self-propulsion. We report on the design and characterization of synthetic self-propelled particles that migrate upstream, known as positive rheotaxis. This phenomenon results from a purely physical mechanism involving the interplay between the polarity of the particles and their alignment by a viscous torque. We show quantitative agreement between experimental data and a simple model of an overdamped Brownian pendulum. The model notably predicts the existence of a stagnation point in a diverging flow. We take advantage of this property to demonstrate that our active particles can sense and predictably organize in an imposed flow. Our colloidal system represents an important step toward the realization of biomimetic microsystems with the ability to sense and respond to environmental changes. PMID:26601175

  13. Artificial atoms based on correlated materials

    NASA Astrophysics Data System (ADS)

    Mannhart, J.; Boschker, H.; Kopp, T.; Valentí, R.

    2016-08-01

    Low-dimensional electron systems fabricated from quantum matter have in recent years become available and are being explored with great intensity. This article gives an overview of the fundamental properties of such systems and summarizes the state of the field. We furthermore present and consider the concept of artificial atoms fabricated from quantum materials, anticipating remarkable scientific advances and possibly important applications of this new field of research. The surprising properties of these artificial atoms and of molecules or even of solids assembled from them are presented and discussed.

  14. Nanostructured composite reinforced material

    DOEpatents

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2012-07-31

    A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

  15. Transparent electrode with a nanostructured coating.

    PubMed

    Huang, Yan Y; Terentjev, Eugene M

    2011-03-22

    Using single-walled nanotubes as an example, we fabricated transparent conductive coatings and demonstrated a new technique of centrifuge coating as a potential low-waste, solution-based batch process for the fabrication of nanostructured coatings. A theoretical model is developed to account for the sheet resistance exhibited by layered random-network coatings such as nanofilaments and graphene. The model equation is analytical and compact, and allows the correlation of very different scaling regimes reported in the literature to the underlying coating microstructure. Finally, we also show a refined experimental setup to systematically measure the curvature-dependent sheet resistance. PMID:21370898

  16. Progress and Design Concerns of Nanostructured Solar Energy Harvesting Devices.

    PubMed

    Leung, Siu-Fung; Zhang, Qianpeng; Tavakoli, Mohammad Mahdi; He, Jin; Mo, Xiaoliang; Fan, Zhiyong

    2016-05-01

    Integrating devices with nanostructures is considered a promising strategy to improve the performance of solar energy harvesting devices such as photovoltaic (PV) devices and photo-electrochemical (PEC) solar water splitting devices. Extensive efforts have been exerted to improve the power conversion efficiencies (PCE) of such devices by utilizing novel nanostructures to revolutionize device structural designs. The thicknesses of light absorber and material consumption can be substantially reduced because of light trapping with nanostructures. Meanwhile, the utilization of nanostructures can also result in more effective carrier collection by shortening the photogenerated carrier collection path length. Nevertheless, performance optimization of nanostructured solar energy harvesting devices requires a rational design of various aspects of the nanostructures, such as their shape, aspect ratio, periodicity, etc. Without this, the utilization of nanostructures can lead to compromised device performance as the incorporation of these structures can result in defects and additional carrier recombination. The design guidelines of solar energy harvesting devices are summarized, including thin film non-uniformity on nanostructures, surface recombination, parasitic absorption, and the importance of uniform distribution of photo-generated carriers. A systematic view of the design concerns will assist better understanding of device physics and benefit the fabrication of high performance devices in the future. PMID:26918386

  17. What can chemists do for nanostructured materials?

    SciTech Connect

    Siegel, R.W. |

    1995-04-01

    Nanostructured materials have now been investigated for more than a decade using a rather wide range of experimental methods. The structures and properties of these new materials, which are artificially synthesized from nanometer-sized ``building blocks``, such as clusters, grains or layers, have been elucidated in a number of important areas and the relationships among these areas are beginning to be understood. Various investigations of their mechanical, chemical, electrical, magnetic, and optical behavior have demonstrated the possibilities to engineer the properties of nanostructured materials through control of the sizes of their constituent clusters, grains or layers and the manner in which these constituents are assembled. There are, however, tremendous opportunities remaining for creative new tailored chemical synthesis and processing methods and for developing an understanding of the important role of surface and interface chemistry in the assembly and resulting properties of these materials. Some aspects of the present understanding of nanostructured materials and their properties are briefly presented here, along with some thoughts regarding a few critical future research needs in various areas of chemistry that would add greatly to the field of nanostructured materials.

  18. Nanostructured biosensing platform-shadow edge lithography for high-throughput nanofabrication.

    PubMed

    Bai, John G; Yeo, Woon-Hong; Chung, Jae-Hyun

    2009-02-01

    One of the critical challenges in nanostructured biosensors is to manufacture an addressable array of nanopatterns at low cost. The addressable array (1) provides multiplexing for biomolecule detection and (2) enables direct detection of biomolecules without labeling and amplification. To fabricate such an array of nanostructures, current nanolithography methods are limited by the lack of either high throughput or high resolution. This paper presents a high-resolution and high-throughput nanolithography method using the compensated shadow effect in high-vacuum evaporation. The approach enables the fabrication of uniform nanogaps down to 20 nm in width across a 100 mm silicon wafer. The nanogap pattern is used as a template for the routine fabrication of zero-, one-, and two-dimensional nanostructures with a high yield. The method can facilitate the fabrication of nanostructured biosensors on a wafer scale at a low manufacturing cost. PMID:19156295

  19. Artificial Respiration and Artificial Circulation

    PubMed Central

    Brook, Joseph; Brook, Morris H.; Lopez, Jose F.

    1965-01-01

    A training program in the newer methods of treatment of acute cardiopulmonary emergencies which was developed at the University Hospital, University of Saskatchewan, is reported. Artificial respiration by the chance rescuer, primary and secondary resuscitation, and post-resuscitation measures involving the use of special drugs and equipment by trained personnel are described. Figures and tables designed for wall-mounting and ready reference in an emergency situation are presented. Firstaid ventilatory adjuncts for use by trained personnel are classified and critically appraised, and the propriety of their use is emphasized. A plea is made to the medical profession and allied agencies to assume the responsibility of spreading knowledge of the new techniques more widely. Unless effective treatment is instituted early enough to prevent death or permanent anoxic damage to heart and brain, follow-through therapy will often be fruitless. PMID:14339303

  20. Scalable nanostructuring on polymer by a SiC stamp: optical and wetting effects

    NASA Astrophysics Data System (ADS)

    Argyraki, Aikaterini; Lu, Weifang; Petersen, Paul M.; Ou, Haiyan

    2015-08-01

    A method for fabricating scalable antireflective nanostructures on polymer surfaces (polycarbonate) is demonstrated. The transition from small scale fabrication of nanostructures to a scalable replication technique can be quite challenging. In this work, an area per print corresponding to a 2-inch-wafer, is presented. The initial nanopatterning is performed on SiC in a 2-step process. Depending on the nanostructures the transmission of the SiC surface can be increased or suppressed (average height of nanostructures ~300nm and ~600nm, respectively) while the reflectance is decreased, when compared to a bare surface. The reflectance of SiC can be reduced down to 0.5% when the ~600nm nanostructures are applied on the surface (bare surface reflectance 25%). The texture of the green SiC color is changed when the different nanostructures are apparent. The ~600nm SiC nanostructures are replicated on polymer through a process flow that involved hot embossing and galvanization. The resulted polymer structures have similar average height and exhibit more rounded edges than the initial SiC nanostructures. The polymer surface becomes antireflective and hydrophobic after nanostructuring. The contact angle changes from 68 (bare) to 123 (nanostructured) degrees. The optical effect on the polymer surface can be maximized by applying a thin aluminum (Al) layer coating on the nanostructures (bare polymer reflectance 11%, nanostructured polymer reflectance 5%, Al coated nanostructured polymer reflectance 3%). The optical measurements were performed with an integrating sphere and a spectrometer. The contact angles were measured with a drop shape analyzer. The nanostructures were characterized with scanning electron microscopy.

  1. Preparation and characterization of photocatalytic carbon dots-sensitized electrospun titania nanostructured fibers

    SciTech Connect

    Li, Haopeng; Zhu, Yihua; Cao, Huimin; Yang, Xiaoling; Li, Chunzhong

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► The TiO{sub 2}-CDs nanostructured fibers are fabricated by using APS combining the electrospinning TiO{sub 2} nanostructured fibers and CDs. ► The CD can work as a photosensitizer in the degradation of rhodamine B under visible light irradiation. ► The TiO{sub 2}-CDs nanostructured fibers exhibit enhanced photocatalytic efficiency and can be easily handled and recycled. -- Abstract: The carbon dots (CDs) are new functional carbon-aceous materials. Compared to conventional dye molecules and semiconductor quantum dots, CDs are superior in chemical inertness and low toxicity. The TiO{sub 2}-CDs nanostructured fibers were fabricated by combining the electrospinning technique and reflux method. Compared with the pure TiO{sub 2} nanostructured fibers and P25, the TiO{sub 2}-CDs nanostructured fibers exhibited enhanced photocatalytic efficiency of photodegradation of rhodamine B (RhB) under visible light irradiation. The enhanced photocatalytic activity of TiO{sub 2}-CDs nanostructured fibers could be attributed to the presence of CDs embedded in TiO{sub 2} nanostructured fibers. The CD can work as a photosensitizer in the degradation. Furthermore, the TiO{sub 2}-CDs nanostructured fibers could be easily handled and recycled due to their one-dimensional nanostructural property.

  2. EDITORIAL: Nanostructures + Light = 'New Optics'

    NASA Astrophysics Data System (ADS)

    Zheludev, Nikolay; Shalaev, Vladimir

    2005-02-01

    Suddenly, at the end of the last century, classical optics and classical electrodynamics became fashionable again. Fields that several generations of researchers thought were comprehensively covered by the famous Born and Wolf textbook and were essentially dead as research subjects were generating new excitement. In accordance with Richard Feynman’s famous quotation on nano-science, the optical community suddenly discovered that 'there is plenty of room at the bottom'—mixing light with small, meso- and nano-structures could generate new physics and new mind-blowing applications. This renaissance began when the concept of band structure was imported from electronics into the domain of optics and led to the development of what is now a massive research field dedicated to two- and three-dimensional photonic bandgap structures. The field was soon awash with bright new ideas and discoveries that consolidated the birth of the 'new optics'. A revision of some of the basic equations of electrodynamics led to the suspicion that we had overlooked the possibility that the triad of wave vector, electric field and magnetic field, characterizing propagating waves, do not necessarily form a right-handed set. This brought up the astonishing possibilities of sub-wavelength microscopy and telescopy where resolution is not limited by diffraction. The notion of meta-materials, i.e. artificial materials with properties not available in nature, originated in the microwave community but has been widely adopted in the domain of optical research, thanks to rapidly improving nanofabrication capabilities and the development of sub-wavelength scanning imaging techniques. Photonic meta-materials are expected to open a gateway to unprecedented electromagnetic properties and functionality unattainable from naturally occurring materials. The structural units of meta-materials can be tailored in shape and size; their composition and morphology can be artificially tuned, and inclusions can be

  3. Elongated nanostructures for radial junction solar cells.

    PubMed

    Kuang, Yinghuan; Vece, Marcel Di; Rath, Jatindra K; Dijk, Lourens van; Schropp, Ruud E I

    2013-10-01

    In solar cell technology, the current trend is to thin down the active absorber layer. The main advantage of a thinner absorber is primarily the reduced consumption of material and energy during production. For thin film silicon (Si) technology, thinning down the absorber layer is of particular interest since both the device throughput of vacuum deposition systems and the stability of the devices are significantly enhanced. These features lead to lower cost per installed watt peak for solar cells, provided that the (stabilized) efficiency is the same as for thicker devices. However, merely thinning down inevitably leads to a reduced light absorption. Therefore, advanced light trapping schemes are crucial to increase the light path length. The use of elongated nanostructures is a promising method for advanced light trapping. The enhanced optical performance originates from orthogonalization of the light's travel path with respect to the direction of carrier collection due to the radial junction, an improved anti-reflection effect thanks to the three-dimensional geometric configuration and the multiple scattering between individual nanostructures. These advantages potentially allow for high efficiency at a significantly reduced quantity and even at a reduced material quality, of the semiconductor material. In this article, several types of elongated nanostructures with the high potential to improve the device performance are reviewed. First, we briefly introduce the conventional solar cells with emphasis on thin film technology, following the most commonly used fabrication techniques for creating nanostructures with a high aspect ratio. Subsequently, several representative applications of elongated nanostructures, such as Si nanowires in realistic photovoltaic (PV) devices, are reviewed. Finally, the scientific challenges and an outlook for nanostructured PV devices are presented. PMID:24088584

  4. Electron-beam induced synthesis of nanostructures: a review

    NASA Astrophysics Data System (ADS)

    Gonzalez-Martinez, I. G.; Bachmatiuk, A.; Bezugly, V.; Kunstmann, J.; Gemming, T.; Liu, Z.; Cuniberti, G.; Rümmeli, M. H.

    2016-06-01

    As the success of nanostructures grows in modern society so does the importance of our ability to control their synthesis in precise manners, often with atomic precision as this can directly affect the final properties of the nanostructures. Hence it is crucial to have both deep insight, ideally with real-time temporal resolution, and precise control during the fabrication of nanomaterials. Transmission electron microscopy offers these attributes potentially providing atomic resolution with near real time temporal resolution. In addition, one can fabricate nanostructures in situ in a TEM. This can be achieved with the use of environmental electron microscopes and/or specialized specimen holders. A rather simpler and rapidly growing approach is to take advantage of the imaging electron beam as a tool for in situ reactions. This is possible because there is a wealth of electron specimen interactions, which, when implemented under controlled conditions, enable different approaches to fabricate nanostructures. Moreover, when using the electron beam to drive reactions no specialized specimen holders or peripheral equipment is required. This review is dedicated to explore the body of work available on electron-beam induced synthesis techniques with in situ capabilities. Particular emphasis is placed on the electron beam-induced synthesis of nanostructures conducted inside a TEM, viz. the e-beam is the sole (or primary) agent triggering and driving the synthesis process.

  5. Electron-beam induced synthesis of nanostructures: a review.

    PubMed

    Gonzalez-Martinez, I G; Bachmatiuk, A; Bezugly, V; Kunstmann, J; Gemming, T; Liu, Z; Cuniberti, G; Rümmeli, M H

    2016-06-01

    As the success of nanostructures grows in modern society so does the importance of our ability to control their synthesis in precise manners, often with atomic precision as this can directly affect the final properties of the nanostructures. Hence it is crucial to have both deep insight, ideally with real-time temporal resolution, and precise control during the fabrication of nanomaterials. Transmission electron microscopy offers these attributes potentially providing atomic resolution with near real time temporal resolution. In addition, one can fabricate nanostructures in situ in a TEM. This can be achieved with the use of environmental electron microscopes and/or specialized specimen holders. A rather simpler and rapidly growing approach is to take advantage of the imaging electron beam as a tool for in situ reactions. This is possible because there is a wealth of electron specimen interactions, which, when implemented under controlled conditions, enable different approaches to fabricate nanostructures. Moreover, when using the electron beam to drive reactions no specialized specimen holders or peripheral equipment is required. This review is dedicated to explore the body of work available on electron-beam induced synthesis techniques with in situ capabilities. Particular emphasis is placed on the electron beam-induced synthesis of nanostructures conducted inside a TEM, viz. the e-beam is the sole (or primary) agent triggering and driving the synthesis process. PMID:27211080

  6. Ferroelectric memory based on nanostructures

    NASA Astrophysics Data System (ADS)

    Liu, Xingqiang; Liu, Yueli; Chen, Wen; Li, Jinchai; Liao, Lei

    2012-06-01

    In the past decades, ferroelectric materials have attracted wide attention due to their applications in nonvolatile memory devices (NVMDs) rendered by the electrically switchable spontaneous polarizations. Furthermore, the combination of ferroelectric and nanomaterials opens a new route to fabricating a nanoscale memory device with ultrahigh memory integration, which greatly eases the ever increasing scaling and economic challenges encountered in the traditional semiconductor industry. In this review, we summarize the recent development of the nonvolatile ferroelectric field effect transistor (FeFET) memory devices based on nanostructures. The operating principles of FeFET are introduced first, followed by the discussion of the real FeFET memory nanodevices based on oxide nanowires, nanoparticles, semiconductor nanotetrapods, carbon nanotubes, and graphene. Finally, we present the opportunities and challenges in nanomemory devices and our views on the future prospects of NVMDs.

  7. Ferroelectric memory based on nanostructures

    PubMed Central

    2012-01-01

    In the past decades, ferroelectric materials have attracted wide attention due to their applications in nonvolatile memory devices (NVMDs) rendered by the electrically switchable spontaneous polarizations. Furthermore, the combination of ferroelectric and nanomaterials opens a new route to fabricating a nanoscale memory device with ultrahigh memory integration, which greatly eases the ever increasing scaling and economic challenges encountered in the traditional semiconductor industry. In this review, we summarize the recent development of the nonvolatile ferroelectric field effect transistor (FeFET) memory devices based on nanostructures. The operating principles of FeFET are introduced first, followed by the discussion of the real FeFET memory nanodevices based on oxide nanowires, nanoparticles, semiconductor nanotetrapods, carbon nanotubes, and graphene. Finally, we present the opportunities and challenges in nanomemory devices and our views on the future prospects of NVMDs. PMID:22655750

  8. Magnetic domain wall manipulation in (Ga,Mn)As nanostructures for spintronic applications

    SciTech Connect

    Wosinski, Tadeusz; Andrearczyk, Tomasz; Figielski, Tadeusz; Olender, Karolina; Wrobel, Jerzy

    2014-02-21

    Ring-shaped nanostructures have been designed and fabricated by electron-beam lithography patterning and chemical etching from thin epitaxial layers of the ferromagnetic semiconductor (Ga,Mn)As. The nanostructures, in a form of planar rings with a slit, were supplied with four electrical terminals and subjected to magneto-transport studies under planar weak magnetic field. Magnetoresistive effects caused by manipulation of magnetic domain walls and magnetization reversal in the nanostructures have been investigated and possible applications of the nanostructures as four-terminal spintronic devices are discussed.

  9. Nanostructured conducting polymers for energy applications: towards a sustainable platform

    NASA Astrophysics Data System (ADS)

    Ghosh, Srabanti; Maiyalagan, Thandavarayan; Basu, Rajendra N.

    2016-03-01

    Recently, there has been tremendous progress in the field of nanodimensional conducting polymers with the objective of tuning the intrinsic properties of the polymer and the potential to be efficient, biocompatible, inexpensive, and solution processable. Compared with bulk conducting polymers, conducting polymer nanostructures possess a high electrical conductivity, large surface area, short path length for ion transport and superior electrochemical activity which make them suitable for energy storage and conversion applications. The current status of polymer nanostructure fabrication and characterization is reviewed in detail. The present review includes syntheses, a deeper understanding of the principles underlying the electronic behavior of size and shape tunable polymer nanostructures, characterization tools and analysis of composites. Finally, a detailed discussion of their effectiveness and perspectives in energy storage and solar light harvesting is presented. In brief, a broad overview on the synthesis and possible applications of conducting polymer nanostructures in energy domains such as fuel cells, photocatalysis, supercapacitors and rechargeable batteries is described.

  10. Sliding wear behavior of nanostructured WC-Co-Cr coatings

    NASA Astrophysics Data System (ADS)

    Wang, Haibin; Wang, Xuezheng; Song, Xiaoyan; Liu, Xuemei; Liu, Xingwei

    2015-11-01

    The nanostructured WC-10Co-4Cr coatings were fabricated by high velocity oxy-fuel spraying using the in situ synthesized WC-Co nanocomposite powder with size of 70-200 nm and Cr addition. Through optimization of the processing conditions, the nanostructured WC-Co-Cr coating has only a small amount of decarburized phase, a dense microstructure and an excellent combination of hardness, fracture toughness and wear resistance. A series of sliding wear tests were performed to investigate the wear behavior of the nanostructured cermet coating. The evolution of the friction coefficient, wear characteristics and their mechanisms were studied for the nanostructured WC-Co-Cr coating with the change of the load. The present study proposes a new understanding of the occurrence and the related mechanisms of the wear of the cermet coatings.

  11. Nanostructured conducting polymers for energy applications: towards a sustainable platform.

    PubMed

    Ghosh, Srabanti; Maiyalagan, Thandavarayan; Basu, Rajendra N

    2016-04-01

    Recently, there has been tremendous progress in the field of nanodimensional conducting polymers with the objective of tuning the intrinsic properties of the polymer and the potential to be efficient, biocompatible, inexpensive, and solution processable. Compared with bulk conducting polymers, conducting polymer nanostructures possess a high electrical conductivity, large surface area, short path length for ion transport and superior electrochemical activity which make them suitable for energy storage and conversion applications. The current status of polymer nanostructure fabrication and characterization is reviewed in detail. The present review includes syntheses, a deeper understanding of the principles underlying the electronic behavior of size and shape tunable polymer nanostructures, characterization tools and analysis of composites. Finally, a detailed discussion of their effectiveness and perspectives in energy storage and solar light harvesting is presented. In brief, a broad overview on the synthesis and possible applications of conducting polymer nanostructures in energy domains such as fuel cells, photocatalysis, supercapacitors and rechargeable batteries is described. PMID:26980404

  12. ZnS:Cr Nanostructures Building Fractals and Their Properties

    SciTech Connect

    Gogoi, D. P.; Das, U.; Mohanta, D.; Ahmed, G. A.; Choudhury, A.

    2010-10-04

    Cr doped ZnS nanostructures have been fabricated through colloidal solution route by using Polyvinyl alcohol (-C{sub 2}H{sub 4}O){sub n} and Polyvinyl pyrrolidone k30 (C{sub 6}H{sub 9}NO){sub x} as dielectric hosts. Growth of fractal structures have been observed through Transmission Electron Microscopy. Higher magnification TEM study reveals that these fractals actually a organize structure of ZnS:Cr nanostructures. The structural study of these nanostructures in the fractals is done by X-Ray Diffraction, UV-Visible spectroscopy, Photoluminescence spectroscopy AFM and MFM. These investigations allow us to form a comprehensive explanation of fractal as well as nanostructure growth. We have done dimensional study of these fractals and the reason behind the formation of these fractals.

  13. Highly Sensitive Plasmonic Optical Sensors Based on Gold Core-Satellite Nanostructures Immobilized on Glass Substrates.

    PubMed

    Ode, Kentaro; Honjo, Mai; Takashima, Yohei; Tsuruoka, Takaaki; Akamatsu, Kensuke

    2016-08-17

    Fabrication of discrete nanostructures consisting of noble metal nanoparticles immobilized on substrates is challenging because of structural complexity but important for chip-based plasmonic sensor technology. Here we report optical sensing capabilities of core-satellite nanostructures made of gold nanoparticles immobilized on glass substrate, which were fabricated by combining stepwise interconnection of gold nanoparticles through dithiol linkers and surface treatment using vacuum ultraviolet light. The nanostructures exhibit large changes in coupled plasmon resonance peak upon surrounding refractive index, with sensitibity of ca. 350 nm RIU(-1), thus providing highly sensitive optical sensors for determining the surrounding refractive index and detecting organic vapors. PMID:27482968

  14. Control of wettability of molecularly thin liquid films by nanostructures.

    PubMed

    Fukuzawa, Kenji; Deguchi, Takanori; Yamawaki, Yasuhiro; Itoh, Shintaro; Muramatsu, Takuro; Zhang, Hedong

    2008-03-18

    The patterning of liquid thin films on solid surfaces is very important in various fields of science and engineering related to surfaces and interfaces. A method of nanometer-scale patterning of a molecularly thin liquid film on a silicon substrate using the lyophobicity of the oxide nanostructures has recently been reported (Fukuzawa, K.; Deguchi, T.; Kawamura, J.; Mitsuya, Y.; Muramatsu, T.; Zhang, H. Appl. Phys. Lett. 2005, 87, 203108). However, the origin of the lyophobicity of the nanostructure with a height of around 1 nm, which was fabricated by probe oxidation, has not yet been clarified. In the present study, the change in thickness of the liquid film on mesa-shaped nanostructures and the wettability for the various combinations of the thickness of the liquid films and the height of ridge-shaped nanostructures were investigated. These revealed that lyophobicity is caused by a lowering of the intermolecular interaction between the liquid and silicon surfaces by the nanostructure and enables the patterning of a liquid film along it. The tendency of the wettability for a given liquid film and nanostructure size can be predicted by estimating the contributions of the intermolecular interaction and capillary pressure. In this method, the height of the nanostructure can control the wettability. These results can provide a novel method of nanoscale patterning of liquid thin films, which will be very useful in creating new functional surfaces. PMID:18237215

  15. Nanostructures of Boron, Carbon and Magnesium Diboride for High Temperature Superconductivity

    SciTech Connect

    Pfefferle, Lisa; Fang, Fang; Iyyamperumal, Eswarmoorthi; Keskar, Gayatri

    2013-12-23

    Direct fabrication of MgxBy nanostructures is achieved by employing metal (Ni,Mg) incorporated MCM-41 in the Hybrid Physical-Chemical Vapor Deposition (HPCVD) reaction. Different reaction conditions are tested to optimize the fabrication process. TEM analysis shows the fabrication of MgxBy nanostructures starting at the reaction temperature of 600oC, with the yield of the nanostructures increasing with increasing reaction temperature. The as-synthesized MgxBy nanostructures have the diameters in the range of 3-5nm, which do not increase with the reaction temperature consistent with templated synthesis. EELS analysis of the template removed nanostructures confirms the existence of B and Mg with possible contamination of Si and O. NEXAFS and Raman spectroscopy analysis suggested a concentric layer-by-layer MgxBy nanowire/nanotube growth model for our as-synthesized nanostructures. Ni k-edge XAS indicates that the formation of MgNi alloy particles is important for the Vapor-Liquid-Solid (VLS) growth of MgxBy nanostructures with fine diameters, and the presence of Mg vapor not just Mg in the catalyst is crucial for the formation of Ni-Mg clusters. Physical templating by the MCM-41 pores was shown to confine the diameter of the nanostructures. DC magnetization measurements indicate possible superconductive behaviors in the as-synthesized samples.

  16. Nanostructuring of metals by severe plastic deformation for advanced properties

    NASA Astrophysics Data System (ADS)

    Valiev, Ruslan

    2004-08-01

    Despite rosy prospects, the use of nanostructured metals and alloys as advanced structural and functional materials has remained controversial until recently. Only in recent years has a breakthrough been outlined in this area, associated both with development of new routes for the fabrication of bulk nanostructured materials and with investigation of the fundamental mechanisms that lead to the new properties of these materials. Although a deep understanding of these mechanisms is still a topic of basic research, pilot commercial products for medicine and microdevices are coming within reach of the market. This progress article discusses new concepts and principles of using severe plastic deformation (SPD) to fabricate bulk nanostructured metals with advanced properties. Special emphasis is laid on the relationship between microstructural features and properties, as well as the first applications of SPD-produced nanomaterials.

  17. Self-assembly and application of diphenylalanine-based nanostructures.

    PubMed

    Yan, Xuehai; Zhu, Pengli; Li, Junbai

    2010-06-01

    Micro- and nanostructures fabricated from biological building blocks have attracted tremendous attention owing to their potential for application in biology and in nanotechnology. Many biomolecules, including peptides and proteins, can interact and self-assemble into highly ordered supramolecular architectures with functionality. By imitating the processes where biological peptides or proteins are assembled in nature, one can delicately design and synthesize various peptide building blocks composed of several to dozens of amino acids for the creation of biomimetic or bioinspired nanostructured materials. This tutorial review aims to introduce a new kind of peptide building block, the diphenylalanine motif, extracted with inspiration of a pathogenic process towards molecular self-assembly. We highlight recent and current advances in fabrication and application of diphenylalanine-based peptide nanomaterials. We also highlight the preparation of such peptide-based nanostructures as nanotubes, spherical vesicles, nanofibrils, nanowires and hybrids through self-assembly, the improvement of their properties and the extension of their applications. PMID:20502791

  18. Plasmonic properties of metal-vanadium dioxide nanostructures

    NASA Astrophysics Data System (ADS)

    Suh, Jae Yong

    This research is concerned with the fabrication of vanadium dioxide in the form of thin films and nanoparticles, and its effect on optical functionality when joined with two kinds of metallic nanostructures. As for the underlying physical phenomena, the metal-insulator phase transition in VO2 and the optical properties are studied. For the modulation of extraordinary transmission, metal-VO2 double-layer subwavelength aperture arrays were fabricated. For the modulation of the localized surface plasmon resonance of noble metal nanoparticles, gold nanoparticle arrays enveloped in a VO 2 thin film were created. These two-dimensional metal nanostructures incorporating a VO2 thin film exhibit a reverse hysteretic behavior and a plasmon resonance shift, respectively. Experimental measurements and simulations confirm that the complex dielectric functions of VO2 play an essential role in controlling the plasmonic properties of metal nanostructures.

  19. Conductance fluctuations in nanostructures

    NASA Astrophysics Data System (ADS)

    Zhu, Ningjia

    1997-12-01

    In this Ph.D thesis the conductance fluctuations of different physical origins in semi-conductor nanostructures were studied using both diagrammatic analytical methods and large scale numerical techniques. In the "mixed" transport regime where both mesoscopic and ballistic features play a role, for the first time I have analytically calculated the non-universal conductance fluctuations. This mixed regime is reached when impurities are distributed near the walls of a quantum wire, leaving the center region ballistic. I have discovered that the existence of a ballistic region destroys the universal conductance fluctuations. The crossover behavior of the fluctuation amplitude from the usual quasi-1D situation to that of the mixed regime is clearly revealed, and the role of various length scales are identified. My analytical predictions were confirmed by a direct numerical simulation by evaluating the Landauer formula. In another direction, I have made several studies of conductance or resistance oscillations and fluctuations in systems with artificial impurities in the ballistic regime. My calculation gave explanations of all the experimental results concerning the classical focusing peaks of the resistance versus magnetic field, the weak localization peak in a Sinai billiard system, the formation of a chaotic billiard, and predicted certain transport features which were indeed found experimentally. I have further extended the calculation to study the Hall resistance in a four-terminal quantum dot in which there is an antidot array. From my numerical data I analyzed the classical paths of electron motion and its quantum oscillations. The results compare well with recent experimental studies on similar systems. Since these billiard systems could provide quantum chaotic dynamics, I have made a detailed study of the consequence of such dynamics. In particular I have investigated the resonant transmission of electrons in these chaotic systems, and found that the level

  20. Biomimetic compound eye with a high numerical aperture and anti-reflective nanostructures on curved surfaces.

    PubMed

    Wang, T; Yu, W; Li, C; Zhang, H; Xu, Z; Lu, Z; Sun, Q

    2012-06-15

    Biomimetic compound eyes with a high numerical aperture on a curved surface were successfully fabricated by intelligent integration of traditional top-down and bottom-up micro- and nanofabrication methods together. In addition, the new hybrid micro- and nanofabrication method allows us to fabricate the antireflective nanostructures on each ommatidium to increase its vision sensitivity by improving the light transmission. The fabricated compound eye was optically characterized and was shown to have a numerical aperture of 0.77 for each ommatidium. Furthermore, it is shown that the transmission of the compound eye can be improved by 2.3% for the wavelength of 632.8 nm and a clearer image can be formed by the fabricated compound eye with antireflective nanostructures compared with that without antireflective nanostructures. In addition, the developed hybrid manufacturing method can be adapted to the fabrication of other complex micro- and nanodevices for photonics or other research areas. PMID:22739920