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Sample records for antireflection coated s-fap

  1. Laser damage initiation and growth of antireflection coated S-FAP crystal surfaces prepared by pitch lap and magnetorheological finishing

    SciTech Connect

    Stolz, C J; Menapace, J A; Schaffers, K I; Bibeau, C; Thomas, M D; Griffin, A J

    2005-10-31

    Antireflection (AR) coatings typically damage at the interface between the substrate and coating. Therefore the substrate finishing technology can have an impact on the laser resistance of the coating. For this study, AR coatings were deposited on Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F] crystals that received a final polish by both conventional pitch lap finishing as well as magnetorheological finishing (MRF). SEM images of the damage morphology reveals laser damage originates at scratches and at substrate coating interfacial absorbing defects. Previous damage stability tests on multilayer mirror coatings and bare surfaces revealed damage growth can occur at fluences below the initiation fluence. The results from this study suggest the opposite trend for AR coatings. Investigation of unstable HR and uncoated surface damage morphologies reveals significant radial cracking that is not apparent with AR damage due to AR delamination from the coated surface with few apparent cracks at the damage boundary. Damage stability tests show that coated Yb:S-FAP crystals can operate at 1057 nm at fluences around 20 J/cm{sup 2} at 10 ns; almost twice the initiation damage threshold.

  2. Metasurface optical antireflection coating

    SciTech Connect

    Zhang, Boyang; Hendrickson, Joshua; Nader, Nima; Chen, Hou -Tong; Guo, Junpeng

    2014-12-15

    Light reflection at the boundary of two different media is one of the fundamental phenomena in optics, and reduction of reflection is highly desirable in many optical systems. Traditionally, optical antireflection has been accomplished using single- or multiple-layer dielectric films and graded index surface structures in various wavelength ranges. However, these approaches either impose strict requirements on the refractive index matching and film thickness, or involve complicated fabrication processes and non-planar surfaces that are challenging for device integration. Here, we demonstrate an antireflection coating strategy, both experimentally and numerically, by using metasurfaces with designer optical properties in the mid-wave infrared. Our results show that the metasurface antireflection is capable of eliminating reflection and enhancing transmission over a broad spectral band and a wide incidence angle range. The demonstrated antireflection technique has no requirement on the choice of materials and is scalable to other wavelengths.

  3. Metasurface optical antireflection coating

    DOE PAGES

    Zhang, Boyang; Hendrickson, Joshua; Nader, Nima; ...

    2014-12-15

    Light reflection at the boundary of two different media is one of the fundamental phenomena in optics, and reduction of reflection is highly desirable in many optical systems. Traditionally, optical antireflection has been accomplished using single- or multiple-layer dielectric films and graded index surface structures in various wavelength ranges. However, these approaches either impose strict requirements on the refractive index matching and film thickness, or involve complicated fabrication processes and non-planar surfaces that are challenging for device integration. Here, we demonstrate an antireflection coating strategy, both experimentally and numerically, by using metasurfaces with designer optical properties in the mid-wave infrared.more » Our results show that the metasurface antireflection is capable of eliminating reflection and enhancing transmission over a broad spectral band and a wide incidence angle range. The demonstrated antireflection technique has no requirement on the choice of materials and is scalable to other wavelengths.« less

  4. Terahertz antireflection coatings using metamaterials

    SciTech Connect

    Chen, Hou-tong; Zhou, Jiangfeng; O' Hara, John F; Azad, Abul K; Chen, Frank; Taylor, Antoinette J

    2010-01-01

    We demonstrate terahertz metamaterial antireflection coatings (ARCs) that significantly reduce the reflection and enhance the transmission at an interface of dielectric media. They are able to operate over a wide range of incidence angles for both TM and TE polarizations. Experiments and finite-element simulations will be presented and discussed.

  5. Loss/gain-induced ultrathin antireflection coatings.

    PubMed

    Luo, Jie; Li, Sucheng; Hou, Bo; Lai, Yun

    2016-06-28

    Tradional antireflection coatings composed of dielectric layers usually require the thickness to be larger than quarter wavelength. Here, we demonstrate that materials with permittivity or permeability dominated by imaginary parts, i.e. lossy or gain media, can realize non-resonant antireflection coatings in deep sub-wavelength scale. Interestingly, while the reflected waves are eliminated as in traditional dielectric antireflection coatings, the transmitted waves can be enhanced or reduced, depending on whether gain or lossy media are applied, respectively. We provide a unified theory for the design of such ultrathin antireflection coatings, showing that under different polarizations and incident angles, different types of ultrathin coatings should be applied. Especially, under transverse magnetic polarization, the requirement shows a switch between gain and lossy media at Brewster angle. As a proof of principle, by using conductive films as a special type of lossy antireflection coatings, we experimentally demonstrate the suppression of Fabry-Pérot resonances in a broad frequency range for microwaves. This valuable functionality can be applied to remove undesired resonant effects, such as the frequency-dependent side lobes induced by resonances in dielectric coverings of antennas. Our work provides a guide for the design of ultrathin antireflection coatings as well as their applications in broadband reflectionless devices.

  6. Loss/gain-induced ultrathin antireflection coatings

    PubMed Central

    Luo, Jie; Li, Sucheng; Hou, Bo; Lai, Yun

    2016-01-01

    Tradional antireflection coatings composed of dielectric layers usually require the thickness to be larger than quarter wavelength. Here, we demonstrate that materials with permittivity or permeability dominated by imaginary parts, i.e. lossy or gain media, can realize non-resonant antireflection coatings in deep sub-wavelength scale. Interestingly, while the reflected waves are eliminated as in traditional dielectric antireflection coatings, the transmitted waves can be enhanced or reduced, depending on whether gain or lossy media are applied, respectively. We provide a unified theory for the design of such ultrathin antireflection coatings, showing that under different polarizations and incident angles, different types of ultrathin coatings should be applied. Especially, under transverse magnetic polarization, the requirement shows a switch between gain and lossy media at Brewster angle. As a proof of principle, by using conductive films as a special type of lossy antireflection coatings, we experimentally demonstrate the suppression of Fabry-Pérot resonances in a broad frequency range for microwaves. This valuable functionality can be applied to remove undesired resonant effects, such as the frequency-dependent side lobes induced by resonances in dielectric coverings of antennas. Our work provides a guide for the design of ultrathin antireflection coatings as well as their applications in broadband reflectionless devices. PMID:27349750

  7. Sol-gel antireflective coating on plastics

    DOEpatents

    Ashley, Carol S.; Reed, Scott T.

    1990-01-01

    An antireflection film made from a reliquified sol-gel hydrolyzation, condensation polymeric reaction product of a silicon, alkoxides and/or metal alkoxides, or mixtures thereof. The film is particularly useful for coating plastics.

  8. Sol-gel antireflective coating on plastics

    DOEpatents

    Ashley, C.S.; Reed, S.T.

    1988-01-26

    An antireflection film made from reliquified sol-gel hydrolyzation, condensation polymeric reaction product of a silicon, alkoxides and/or metal alkoxides, or mixtures thereof. The film is particularly useful for coating plastics.

  9. Broadband antireflective coating for NEOSTED

    NASA Astrophysics Data System (ADS)

    Budasz, Jiří; Junek, Jiří; Václavík, Jan

    2016-11-01

    This paper deals with the development of a broadband antireflective coating for a special optical components for the NEOSTED project by European Space Agency (ESA). The aim of this work was to find a suitable design of the optical coating and to develop its production process so it meets the main requirement in which the average reflectance of the coating must be under 0.5 % for wavelengths in the range of 470 - 770 nm. The combination of titanium dioxide (TiO2) and silicon dioxide (SiO2) prepared by the ion beam assisted deposition (IBAD) was chosen for practical experiments and finally for the production as well. The final decision among the proposed designs and materials involved especially the number of layers used in the design in combination with the thickness control technology. From preproduction tests it turned out that the quartz monitor with the thickness set point correction based on a post process measurement is suitable for controlling deposited thickness in the application. This paper presents data from the preproduction tests and data from the first part of the production. A homogeneity of the deposited layer thickness was evaluated based on the measurement of the thickness across the sample.

  10. Yb:S-FAP Lasers

    SciTech Connect

    Schaffers, K I

    2004-01-20

    It has recently been reported that several high power, diode-pumped laser systems have been developed based on crystals of Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F]. The Mercury Laser, at Lawrence Livermore National Laboratory, is the most prominent system using Yb:S-FAP and is currently producing 23J at 5 Hz in a 15 nsec pulse, based on partial activation of the system. In addition, a regenerative amplifier is being developed at Waseda University in Japan and has produced greater than 12 mJ with high beam quality at 50Hz repetition rate. Q-peak has demonstrated 16 mJ of maximum energy/output pulse in a multi-pass, diode side-pumped amplifier and ELSA in France is implementing Yb:S-FAP in a 985 nm pump for an EDFA, producing 250 mW. Growth of high optical quality crystals of Yb:S-FAP is a challenge due to multiple crystalline defects. However, at this time, a growth process has been developed to produce high quality 3.5 cm diameter Yb:S-FAP crystals and a process is under development for producing 6.5 cm diameter crystals.

  11. Inexpensive Antireflection Coating for Solar Cells

    NASA Technical Reports Server (NTRS)

    Tracy, C. E.; Kern, W.; Vibronek, R. D.

    1982-01-01

    Continuous method for applying antireflection coating to solar cells increases efficiency of devices by preventing energy from being reflected away, but adds little to manufacturing cost. Method consists of spraying solution on cells or glass collector plates, drying sprayed layer, and curing it. Solution is formulated to spread evenly over surfaces.

  12. Ammonia hardening of porous silica antireflective coatings

    NASA Astrophysics Data System (ADS)

    Belleville, Philippe F.; Floch, Herve G.

    1994-10-01

    The adhesion of sol-gel antireflective porous silica coatings on vitreous optical substrates has been dramatically improved by exposure to ammonia vapors or a dip in basic solutions. The approximately 70 to 270-nm thick coatings consisted of monolayers of spherical, 20-nm diameter amorphous silica particles deposited from ethanolic colloidal suspensions by conventional liquid coating techniques. Although, the as-deposited coatings had only low adhesion and were easily damaged when cleaned by standard drag-wiping procedures, coatings exposed over 5 hours to ammonia vapors passed both adhesive-tape and moderate abrasive- resistance tests. The increase in strength was accompanied by a roughly 20% shrinkage of the original coating thickness but the antireflective properties were retained. Our explanation of this chemical effect is a base-catalyzed phenomenon leading to surface silanol condensation and hydrogen-bonding of neighbor silica particles. In addition, since this basic treatment enhanced the laser damage resistance, such strengthened antireflective coatings have been successfully evaluated on flashlamps used on Phebus, Europe's most powerful laser. This allows an increase of the laser-disk pumping efficiency.

  13. Plasmonic and silicon spherical nanoparticle antireflective coatings

    PubMed Central

    Baryshnikova, K. V.; Petrov, M. I.; Babicheva, V. E.; Belov, P. A.

    2016-01-01

    Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflective properties of plasmonic and all-dielectric nanoparticle coatings based on silver and crystalline silicon respectively. Our simulation results for spherical nanoparticles array on top of amorphous silicon show that both silicon and silver coatings demonstrate strong antireflective properties in the visible spectral range. For the first time, we show that zero reflectance from the structure with silicon coatings originates from the destructive interference of electric- and magnetic-dipole responses of nanoparticle array with the wave reflected from the substrate, and we refer to this reflection suppression as substrate-mediated Kerker effect. We theoretically compare the silicon and silver coating effectiveness for the thin-film photovoltaic applications. Silver nanoparticles can be more efficient, enabling up to 30% increase of the overall absorbance in semiconductor layer. Nevertheless, silicon coatings allow up to 64% absorbance increase in the narrow band spectral range because of the substrate-mediated Kerker effect, and band position can be effectively tuned by varying the nanoparticles sizes. PMID:26926602

  14. Plasmonic and silicon spherical nanoparticle antireflective coatings

    NASA Astrophysics Data System (ADS)

    Baryshnikova, K. V.; Petrov, M. I.; Babicheva, V. E.; Belov, P. A.

    2016-03-01

    Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflective properties of plasmonic and all-dielectric nanoparticle coatings based on silver and crystalline silicon respectively. Our simulation results for spherical nanoparticles array on top of amorphous silicon show that both silicon and silver coatings demonstrate strong antireflective properties in the visible spectral range. For the first time, we show that zero reflectance from the structure with silicon coatings originates from the destructive interference of electric- and magnetic-dipole responses of nanoparticle array with the wave reflected from the substrate, and we refer to this reflection suppression as substrate-mediated Kerker effect. We theoretically compare the silicon and silver coating effectiveness for the thin-film photovoltaic applications. Silver nanoparticles can be more efficient, enabling up to 30% increase of the overall absorbance in semiconductor layer. Nevertheless, silicon coatings allow up to 64% absorbance increase in the narrow band spectral range because of the substrate-mediated Kerker effect, and band position can be effectively tuned by varying the nanoparticles sizes.

  15. Plasmonic and silicon spherical nanoparticle antireflective coatings.

    PubMed

    Baryshnikova, K V; Petrov, M I; Babicheva, V E; Belov, P A

    2016-03-01

    Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflective properties of plasmonic and all-dielectric nanoparticle coatings based on silver and crystalline silicon respectively. Our simulation results for spherical nanoparticles array on top of amorphous silicon show that both silicon and silver coatings demonstrate strong antireflective properties in the visible spectral range. For the first time, we show that zero reflectance from the structure with silicon coatings originates from the destructive interference of electric- and magnetic-dipole responses of nanoparticle array with the wave reflected from the substrate, and we refer to this reflection suppression as substrate-mediated Kerker effect. We theoretically compare the silicon and silver coating effectiveness for the thin-film photovoltaic applications. Silver nanoparticles can be more efficient, enabling up to 30% increase of the overall absorbance in semiconductor layer. Nevertheless, silicon coatings allow up to 64% absorbance increase in the narrow band spectral range because of the substrate-mediated Kerker effect, and band position can be effectively tuned by varying the nanoparticles sizes.

  16. Antireflective Coatings for Glass and Transparent Polymers.

    PubMed

    Buskens, Pascal; Burghoorn, Marieke; Mourad, Maurice Christian Danho; Vroon, Zeger

    2016-07-12

    Antireflective coatings (ARCs) are applied to reduce surface reflections. We review coatings that reduce the reflection of the surface of the transparent substrates float glass, polyethylene terephthalate, poly(methyl methacrylate), and polycarbonate. Three main coating concepts exist to lower the reflection at the interface of a transparent substrate and air: multilayer interference coatings, graded index coatings, and quarter-wave coatings. We introduce and discuss these three concepts, and zoom in on porous quarter-wave coatings comprising colloidal particles. We extensively discuss the four routes for introducing porosity in quarter-wave coatings through the use of colloidal particles, which have the highest potential for application: (1) packing of dense nanospheres, (2) integration of voids through hollow nanospheres, (3) integration of voids through sacrificial particle templates, and (4) packing of nonspherical nanoparticles. Finally, we address the remaining challenges in the field of ARCs, and elaborate on potential strategies for future research in this area.

  17. Optical enhancing durable anti-reflective coating

    DOEpatents

    Maghsoodi, Sina; Varadarajan, Aravamuthan; Movassat, Meisam

    2016-07-05

    Disclosed herein are polysilsesquioxane based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In embodiments, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in the polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, Si--OH condensation catalyst and/or nanofillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes including flow coating and roll coating, and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

  18. Anti-reflective coating for multipatterning lithography

    NASA Astrophysics Data System (ADS)

    Guerrero, Douglas J.; Gibbons, Steve; Lowes, Joyce; Mercado, Ramil

    2008-03-01

    New bottom anti-reflective coatings (BARCs) have been developed that can be incorporated into multiple patterning schemes utilizing scanner-track-only processes. The BARCs have modifiable optical properties and can be removed during the resist development step. Several dual patterning schemes were investigated for trench printing. The most promising process produced 110 nm trenches with approximately 1:1 space ratios. The etch characteristics of these BARCs under fluorinated and oxygenated gases were determined.

  19. High gain durable anti-reflective coating

    DOEpatents

    Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze'ev R.

    2016-07-26

    Disclosed herein are polysilsesquioxane-based anti-reflective coating (ARC) compositions, methods of preparation, and methods of deposition on a substrate. In one embodiment, the polysilsesquioxane of this disclosure is prepared in a two-step process of acid catalyzed hydrolysis of organoalkoxysilane followed by addition of tetralkoxysilane that generates silicone polymers with >40 mol % silanol based on Si-NMR. These high silanol siloxane polymers are stable and have a long shelf-life in polar organic solvents at room temperature. Also disclosed are low refractive index ARC made from these compositions with and without additives such as porogens, templates, thermal radical initiator, photo radical initiators, crosslinkers, Si--OH condensation catalyst and nano-fillers. Also disclosed are methods and apparatus for applying coatings to flat substrates including substrate pre-treatment processes, coating processes and coating curing processes including skin-curing using hot-air knives. Also disclosed are coating compositions and formulations for highly tunable, durable, highly abrasion-resistant functionalized anti-reflective coatings.

  20. Scandium oxide antireflection coatings for superluminescent LEDs

    NASA Technical Reports Server (NTRS)

    Ladany, I.; Zanzucchi, P. J.; Andrews, J. T.; Kane, J.; Depiano, E.

    1986-01-01

    For an employment of laser diodes as superluminescent LEDs (SLDs) or amplifiers, the facets of the diodes must be coated with antireflection films. In the work reported, scandium oxide was evaporated from an e-beam source onto Supersil II fused silica substrates. The obtained samples were used for measurements of absorption and reflectivity. Results of index measurements on e-beam evaporated films are presented. It is shown that excellent coatings with reflectivities of 0.00025 can be obtained using these films. Attention is given to the refractive indices for scandium oxide films as a function of wavelength, the power output vs current for laser before coating and after coating with Sc2O3.

  1. Buried nanoantenna arrays: versatile antireflection coating.

    PubMed

    Kabiri, Ali; Girgis, Emad; Capasso, Federico

    2013-01-01

    Reflection is usually a detrimental phenomenon in many applications such as flat-panel-displays, solar cells, photodetectors, infrared sensors, and lenses. Thus far, to control and suppress the reflection from a substrate, numerous techniques including dielectric interference coatings, surface texturing, adiabatic index matching, and scattering from plasmonic nanoparticles have been investigated. A new technique is demonstrated to manage and suppress reflection from lossless and lossy substrates. It provides a wider flexibility in design versus previous methods. Reflection from a surface can be suppressed over a narrowband, wideband, or multiband frequency range. The antireflection can be dependent or independent of the incident wave polarization. Moreover, antireflection at a very wide incidence angle can be attained. The reflection from a substrate is controlled by a buried nanoantenna array, a structure composed of (1) a subwavelength metallic array and (2) a dielectric cover layer referred to as a superstrate. The material properties and thickness of the superstrate and nanoantennas' geometry and periodicity control the phase and intensity of the wave circulating inside the superstrate cavity. A minimum reflectance of 0.02% is achieved in various experiments in the mid-infrared from a silicon substrate. The design can be integrated in straightforward way in optical devices. The proposed structure is a versatile AR coating to optically impedance matches any substrate to free space in selected any narrow and broadband spectral response across the entire visible and infrared spectrum.

  2. New antireflective coatings for 193-nm lithography

    NASA Astrophysics Data System (ADS)

    Xu, Gu; Guerrero, Douglas J.; Dobson, Norman

    1998-06-01

    New bottom antireflective coatings (BARCs) for 193 nm lithography have been recently developed by Brewer Science Inc. Copolymers of benzyl methacrylate (or benzyl acrylate) and hydroxypropyl methacrylate have been synthesized and used as a main component in 193 nm BARCs. The acrylic copolymers have strong absorbance at 193 nm UV light wavelength. The 193 nm BARCs were formulated in safe solvents such as ethyl lactate and formed by spin-on coating process. Thermosetting of the 193 nm BARCs limited their intermixing with photoresists. These 193 nm BARCs had optical density of about 10 micrometers -1, k equals 0.35, and n equals 1.81. Preliminary oxygen plasma etch rates were > 1.5 times DUV resists. Good profiles at small feature sizes (< 0.20 micrometers ) were achieved with tested photoresists.

  3. Self-cleaning antireflective optical coatings.

    PubMed

    Guldin, Stefan; Kohn, Peter; Stefik, Morgan; Song, Juho; Divitini, Giorgio; Ecarla, Fanny; Ducati, Caterina; Wiesner, Ulrich; Steiner, Ullrich

    2013-01-01

    Low-cost antireflection coatings (ARCs) on large optical surfaces are an ingredient-technology for high-performance solar cells. While nanoporous thin films that meet the zero-reflectance conditions on transparent substrates can be cheaply manufactured, their suitability for outdoor applications is limited by the lack of robustness and cleanability. Here, we present a simple method for the manufacture of robust self-cleaning ARCs. Our strategy relies on the self-assembly of a block-copolymer in combination with silica-based sol-gel chemistry and preformed TiO2 nanocrystals. The spontaneous dense packing of copolymer micelles followed by a condensation reaction results in an inverse opal-type silica morphology that is loaded with TiO2 photocatalytic hot-spots. The very low volume fraction of the inorganic network allows the optimization of the antireflecting properties of the porous ARC despite the high refractive index of the embedded photocatalytic TiO2 nanocrystals. The resulting ARCs combine high optical and self-cleaning performance and can be deposited onto flexible plastic substrates.

  4. Recent progress in 193-nm antireflective coatings

    NASA Astrophysics Data System (ADS)

    Meador, James D.; Guerrero, Douglas J.; Xu, Gu; Shao, Xie; Dobson, Norman; Claypool, James B.; Nowak, Kelly A.

    1999-06-01

    This paper presents the chemistries and properties of organic, spin-on, bottom antireflective coatings (BARCs) that are designed for 193 nm lithography. All of the BARCs are thermosetting and use dye-attached/incorporated polymers. A first generation product, NEXT, will soon be commercialized. NEXT is built form i-line and deep-UV chemistries with the polymeric constituent being a substitute novolac. This product provide outstanding resolution of 0.16 micrometers L/S with several 193 nm photoresists. Second generation chemical platforms under study include acrylics, polyesters, and polyethers with the 193 nm absorbing chromophore being an aromatic function. The performance of selected BARCs from the four platforms is described, including: optical properties, 193 nm litho, plasma etch rates, Prolith modeling data, spin-bowl and waste line compatibility, and ambient stability.

  5. Adhesion of Antireflective Coatings in Multijunction Photovoltaics

    SciTech Connect

    Brock, Ryan; Miller, David C.; Dauskardt, Reinhold H.

    2016-11-21

    The development of a new composite dual cantilever beam (cDCB) thin-film adhesion testing method is reported, which allows the measurement of adhesion on the fragile thin substrates used in multijunction photovoltaics. We address the adhesion of several antireflective coating systems on multijunction cells. By varying interface chemistry and morphology, we demonstrate the ensuing effects on adhesion and help to develop an understanding of how high adhesion can be achieved, as adhesion values ranging from 0.5 J/m2 to 10 J/m2 were measured. Damp Heat (85 degrees C/85% RH) was used to invoke degradation of interfacial adhesion. We show that even with germanium substrates that fracture easily, quantitative measurements of adhesion can still be made at high test yield. The cDCB test is discussed as an important new methodology, which can be broadly applied to any system that makes use of thin, brittle, or otherwise fragile substrates.

  6. Subwavelength single layer absorption resonance antireflection coatings.

    PubMed

    Huber, S P; van de Kruijs, R W E; Yakshin, A E; Zoethout, E; Boller, K-J; Bijkerk, F

    2014-01-13

    We present theoretically derived design rules for an absorbing resonance antireflection coating for the spectral range of 100 - 400 nm, applied here on top of a molybdenum-silicon multilayer mirror (Mo/Si MLM) as commonly used in extreme ultraviolet lithography. The design rules for optimal suppression are found to be strongly dependent on the thickness and optical constants of the coating. For wavelengths below λ ∼ 230 nm, absorbing thin films can be used to generate an additional phase shift and complement the propagational phase shift, enabling full suppression already with film thicknesses far below the quarter-wave limit. Above λ ∼ 230 nm, minimal absorption (k < 0.2) is necessary for low reflectance and the minimum required layer thickness increases with increasing wavelength slowly converging towards the quarter-wave limit.As a proof of principle, SixCyNz thin films were deposited that exhibit optical constants close to the design rules for suppression around 285 nm. The thin films were deposited by electron beam co-deposition of silicon and carbon, with N+ ion implantation during growth and analyzed with variable angle spectroscopic ellipsometry to characterize the optical constants. We report a reduction of reflectance at λ = 285 nm, from 58% to 0.3% for a Mo/Si MLM coated with a 20 nm thin film of Si0.52C0.16N0.29.

  7. Advanced Antireflection Coatings for High-Performance Solar Energy Applications

    NASA Technical Reports Server (NTRS)

    Pan, Noren

    2015-01-01

    Phase II objectives: Develop and refine antireflection coatings incorporating lanthanum titanate as an intermediate refractive index material; Investigate wet/dry thermal oxidation of aluminum containing semiconductor compounds as a means of forming a more transparent window layer with equal or better optical properties than its unoxidized form; Develop a fabrication process that allows integration of the oxidized window layer and maintains the necessary electrical properties for contacting the solar cell; Conduct an experimental demonstration of the best candidates for improved antireflection coatings.

  8. High gain durable anti-reflective coating with oblate voids

    DOEpatents

    Maghsoodi, Sina; Brophy, Brenor L.; Colson, Thomas E.; Gonsalves, Peter R.; Abrams, Ze'ev

    2016-06-28

    Disclosed herein are single layer transparent coatings with an anti-reflective property, a hydrophobic property, and that are highly abrasion resistant. The single layer transparent coatings contain a plurality of oblate voids. At least 1% of the oblate voids are open to a surface of the single layer transparent coatings.

  9. Multilayer Anti-Reflective Coating Development for PMMA Fresnel Lenses

    DTIC Science & Technology

    2010-06-07

    been sputter deposited on UV transparent polymethylmethacrylate (UVT-PMMA) windows. The amorphous coatings are deposited using reactive sputtering in a...SUBJECT TERMS Anti-reflective coatings, Fresnel lens, polymethylmethacrylate , PMMA 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18...high quality dielectric materials deposited on a variety of substrates including polymethylmethacrylate (PMMA)  Highly amorphous films achieved

  10. Silicon solar cells with Al2O3 antireflection coating

    NASA Astrophysics Data System (ADS)

    Dobrzański, Leszek; Szindler, Marek; Drygała, Aleksandra; Szindler, Magdalena

    2014-09-01

    The paper presents the possibility of using Al2O3 antireflection coatings deposited by atomic layer deposition ALD. The ALD method is based on alternate pulsing of the precursor gases and vapors onto the substrate surface and then chemisorption or surface reaction of the precursors. The reactor is purged with an inert gas between the precursor pulses. The Al2O3 thin film in structure of the finished solar cells can play the role of both antireflection and passivation layer which will simplify the process. For this research 50×50 mm monocrystalline silicon solar cells with one bus bar have been used. The metallic contacts were prepared by screen printing method and Al2O3 antireflection coating by ALD method. Results and their analysis allow to conclude that the Al2O3 antireflection coating deposited by ALD has a significant impact on the optoelectronic properties of the silicon solar cell. For about 80 nm of Al2O3 the best results were obtained in the wavelength range of 400 to 800 nm reducing the reflection to less than 1%. The difference in the solar cells efficiency between with and without antireflection coating was 5.28%. The LBIC scan measurements may indicate a positive influence of the thin film Al2O3 on the bulk passivation of the silicon.

  11. Temperature dependence of porous silica antireflective (AR) coating

    NASA Astrophysics Data System (ADS)

    Tang, Yongxing; Le, Yueqin; Zhang, Weiqing; Jiang, Minhua; Sun, Jinren; Liu, Xiaolin

    1998-02-01

    In this paper, the antireflective coatings consisting of porous silica particles from a silica sol are applied by dip method. The relationships among composition, viscosity and temperature have been studied. The coating homogeneity is opium for the laser wavelengths of 1064 nm, 532 nm and 355 nm. The peak transmission of coated BK-7 glass substrate is higher than 99.5%. The laser induced damage thresholds of the antireflective coatings were range of 7 - 10 J/cm2, for 1 ns pulse width and 1064 nm wavelength. These damage thresholds were suitable for our national ICF program. It is noted that the optical homogeneity of coating and the viscosity of coating sol were strongly influenced by the temperatures in the duration of sol ripening.

  12. Stability of antireflection coatings for large area glazing

    SciTech Connect

    Chinyama, G.K. ); Roos, A. ); Karlsson, B. )

    1993-02-01

    The authors draw attention to the excellent stability of the antireflection (AR) coatings on glass prepared by liquid-phase etching in a silica supersaturated flousilicic acid in comparison to dipping in a teflon sol. Both methods resulted in both sides of the glass being coated with antireflection films. For the best samples the transmission of the original glass was increased by as much as 5.5%. The samples have then been exposed to weathering for about seven years to test their durability, after which their optical properties were measured again. Even after this long period of outdoor exposure, the acid-etched samples show remarkable stability in their antireflection properties. After cleaning, their transmittance is restored to almost pre-exposure levels. 23 refs., 7 figs., 3 tabs.

  13. Anti-reflection coatings applied by acid leaching process

    NASA Technical Reports Server (NTRS)

    Pastirik, E.

    1980-01-01

    The Magicote C process developed by S.M. Thompsen was evaluated for use in applying an antireflective coating to the cover plates of solar panels. The process uses a fluosilicic acid solution supersaturated with silica at elevated temperature to selectively attack the surface of soda-lime glass cover plates and alter the physical and chemical composition of a thin layer of glass. The altered glass layer constitutes an antireflective coating. The process produces coatings of excellent optical quality which possess outstanding resistance to soiling and staining. The coatings produced are not resistant to mechanical abrasion and are attacked to some extent by glass cleansers. Control of the filming process was found to be difficult.

  14. Sol-gel derived contamination resistant antireflective coatings

    NASA Astrophysics Data System (ADS)

    Shen, Jun; Liu, Yuan; Wu, Guangming; Zhou, Bin; Zhang, Zhihua; Zhu, Yumei

    2011-02-01

    Silica-based sol-gel antireflective (AR) optical coatings are critical components for high peak power laser systems. It is well known that water vapor and volatile organic compounds in both the laser bay and target bay environments will reduce the antireflective efficiency and laser-damage resistance of the sol-gel AR coating. In this study, alkylation with organosilanes in the vapor state was investigated. Sol-gel AR coatings were vapor-phase treated with hexamethyldisilazane (HMDS) and trimethylchlorosilane (TMCS) at room temperature, and the resulting post-treated sol-gel AR coatings were tested for their resistance to contamination by a series of volatile organic compounds. Contact angle measurements were taken to discern the degree of silanization. After the vapor treatment of sol-gel AR coatings with organosilanes, the spectral performance of the coatings were analyzed by spectrophotometer, both before and after the exposure to volatile organic compounds. It is found that the coatings treated with ammonia and HMDS show a better contamination resistant capability. After being contaminated 70 hours with hexane, the transmittance of the coatings presents no obvious decrease. And the vapor treatment produces an increase in their damage threshold at 1064 nm (10ns pulse width) as compared to untreated control samples.

  15. Sol-gel derived contamination resistant antireflective coatings

    NASA Astrophysics Data System (ADS)

    Shen, Jun; Liu, Yuan; Wu, Guangming; Zhou, Bin; Zhang, Zhihua; Zhu, Yumei

    2010-10-01

    Silica-based sol-gel antireflective (AR) optical coatings are critical components for high peak power laser systems. It is well known that water vapor and volatile organic compounds in both the laser bay and target bay environments will reduce the antireflective efficiency and laser-damage resistance of the sol-gel AR coating. In this study, alkylation with organosilanes in the vapor state was investigated. Sol-gel AR coatings were vapor-phase treated with hexamethyldisilazane (HMDS) and trimethylchlorosilane (TMCS) at room temperature, and the resulting post-treated sol-gel AR coatings were tested for their resistance to contamination by a series of volatile organic compounds. Contact angle measurements were taken to discern the degree of silanization. After the vapor treatment of sol-gel AR coatings with organosilanes, the spectral performance of the coatings were analyzed by spectrophotometer, both before and after the exposure to volatile organic compounds. It is found that the coatings treated with ammonia and HMDS show a better contamination resistant capability. After being contaminated 70 hours with hexane, the transmittance of the coatings presents no obvious decrease. And the vapor treatment produces an increase in their damage threshold at 1064 nm (10ns pulse width) as compared to untreated control samples.

  16. Wide spectrum antireflective coating for laser fusion systems. Final report

    SciTech Connect

    Yoldas, B.E; Partlow, D.P.; Smith, H.D.; Mattox, D.M.

    1984-01-13

    A method of depositing a laser damage resistant, wide-spectrum antireflective coating on fused silica has been developed. This work was sponsored under a subcontract with the University of California, with technical direction from the Lawrence Livermore National Laboratory. The coating is applied from a specific silanol polymer solution and converted to a porous SiO/sub 2/ film. The pore size of the film is first reduced by a heat treatment to prevent uv scattering. Then gradation of the pore volume is achieved by a mild etching to a sufficient depth to prevent a smoother index transition from air to the substrate glass. The resulting antireflectivity covers the entire transmission range of silica and may be extended to a wavelength as short as 250 nm. Laser damage thresholds as high as 9 j/cm/sup 2/ have been demonstrated on processed samples.

  17. NIF Anti-Reflective Coating Solutions: Preparation, Procedures and Specifications

    SciTech Connect

    Suratwala, T; Carman, L; Thomas, I

    2003-07-01

    The following document contains a detailed description of the preparation procedures for the antireflective coating solutions used for NIF optics. This memo includes preparation procedures for the coating solutions (sections 2.0-4.0), specifications and vendor information of the raw materials used and on all equipment used (section 5.0), and QA specifications (section 6.0) and procedures (section 7.0) to determine quality and repeatability of all the coating solutions. There are different five coating solutions that will be used to coat NIF optics. These solutions are listed below: (1) Colloidal silica (3%) in ethanol (2) Colloidal silica (2%) in sec-butanol (3) Colloidal silica (9%) in sec-butanol (deammoniated) (4) HMDS treated silica (10%) in decane (5) GR650 (3.3%) in ethanol/sec-butanol The names listed above are to be considered the official name for the solution. They will be referred to by these names in the remainder of this document. Table 1 gives a summary of all the optics to be coated including: (1) the surface to be coated; (2) the type of solution to be used; (3) the coating method (meniscus, dip, or spin coating) to be used; (4) the type of coating (broadband, 1?, 2?, 3?) to be made; (5) number of optics to be coated; and (6) the type of post processing required (if any). Table 2 gives a summary of the batch compositions and measured properties of all five of these solutions.

  18. Silicon Nitride Antireflection Coatings for Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Johnson, C.; Wydeven, T.; Donohoe, K.

    1984-01-01

    Chemical-vapor deposition adapted to yield graded index of refraction. Silicon nitride deposited in layers, refractive index of which decreases with distance away from cell/coating interface. Changing index of refraction allows adjustment of spectral transmittance for wavelengths which cell is most effective at converting light to electric current. Average conversion efficiency of solar cells increased from 8.84 percent to 12.63 percent.

  19. Novel Passivating/Antireflective Coatings for Space Solar Cells

    NASA Technical Reports Server (NTRS)

    Faur, Mircea; Faur, Maria; Bailey, S. G.; Flood, D. J.; Faur, H. M.; Mateescu, C. G.; Alterovitz, S. A.; Scheiman, D.; Jenkins, P. P.; Brinker, D. J.

    2005-01-01

    We are developing a novel process to grow passivating/antireflective (AR) coatings for terrestrial and space solar cells. Our approach involves a Room Temperature Wet Chemical Growth (RTWCG) process, which was pioneered, and is under development at SPECMAT, Inc., under a Reimbursable Space Act Agreement with NASA Glenn Research Center. The RTWCG passivating/AR coatings with graded index of refraction are applied in one easy step on finished (bare) cells. The RTWCG coatings grown on planar, textured and porous Si, as well as on poly-Si, CuInSe2, and III-V substrates, show excellent uniformity irrespective of surface topography, crystal orientation, size and shape. In this paper we present some preliminary results of the RTWCG coatings on Si and III-V substrates that show very good potential for use as a passivation/AR coating for space solar cell applications. Compared to coatings grown using conventional techniques, the RTWCG coatings have the potential to reduce reflection losses and improve current collection near the illuminated surface of space solar cells, while reducing the fabrication costs.

  20. Ultraviolet antireflection coatings for use in silicon detector design

    NASA Astrophysics Data System (ADS)

    Hamden, Erika T.; Greer, Frank; Hoenk, Michael E.; Blacksberg, Jordana; Dickie, Matthew R.; Nikzad, Shouleh; Martin, D. Christopher; Schiminovich, David

    2011-07-01

    We report on the development of coatings for a charged-coupled device (CCD) detector optimized for use in a fixed dispersion UV spectrograph. Because of the rapidly changing index of refraction of Si, single layer broadband antireflection (AR) coatings are not suitable to increase quantum efficiency at all wavelengths of interest. Instead, we describe a creative solution that provides excellent performance over UV wavelengths. We describe progress in the development of a coated CCD detector with theoretical quantum efficiencies (QEs) of greater than 60% at wavelengths from 120 to 300nm. This high efficiency may be reached by coating a backside-illuminated, thinned, delta-doped CCD with a series of thin film AR coatings. The materials tested include MgF2 (optimized for highest performance from 120--150nm), SiO2 (150--180nm), Al2O3 (180--240nm), MgO (200--250nm), and HfO2 (240--300nm). A variety of deposition techniques were tested and a selection of coatings that minimized reflectance on a Si test wafer were applied to functional devices. We also discuss future uses and improvements, including graded and multilayer coatings.

  1. Ultraviolet antireflection coatings for use in silicon detector design.

    PubMed

    Hamden, Erika T; Greer, Frank; Hoenk, Michael E; Blacksberg, Jordana; Dickie, Matthew R; Nikzad, Shouleh; Martin, D Christopher; Schiminovich, David

    2011-07-20

    We report on the development of coatings for a charged-coupled device (CCD) detector optimized for use in a fixed dispersion UV spectrograph. Because of the rapidly changing index of refraction of Si, single layer broadband antireflection (AR) coatings are not suitable to increase quantum efficiency at all wavelengths of interest. Instead, we describe a creative solution that provides excellent performance over UV wavelengths. We describe progress in the development of a coated CCD detector with theoretical quantum efficiencies (QEs) of greater than 60% at wavelengths from 120 to 300 nm. This high efficiency may be reached by coating a backside-illuminated, thinned, delta-doped CCD with a series of thin film AR coatings. The materials tested include MgF(2) (optimized for highest performance from 120-150 nm), SiO(2) (150-180 nm), Al(2)O(3) (180-240 nm), MgO (200-250 nm), and HfO(2) (240-300 nm). A variety of deposition techniques were tested and a selection of coatings that minimized reflectance on a Si test wafer were applied to functional devices. We also discuss future uses and improvements, including graded and multilayer coatings.

  2. Wide spectral range characterization of antireflective coatings and their optimization

    NASA Astrophysics Data System (ADS)

    Franta, Daniel; Nečas, David; Ohlídal, Ivan; Jankuj, Jiří

    2015-09-01

    Development of antireflective coatings realized by thin film systems requires their characterization and optimization of their properties. Functional properties of such interference devices are determined by optical constants and thicknesses of the individual films and various defects taking place in these systems. In optics industry the characterization of the films is mostly performed in a relatively narrow spectral range using simple dispersion models and, moreover, the defects are not taken into account at all. This manner of characterization fails if applied to real-world non-ideal thin film systems because the measured data do not contain sufficient information about all the parameters describing the system including imperfections. Reliable characterization requires the following changes: extension of spectral range of measurements, combination of spectrophotometry and ellipsometry, utilization of physically correct dispersion models (Kramers-Kronig consistency, sum rules), inclusion of structural defects instrument imperfection into the models and simultaneous processing of all experimental data. This enables us to remove or reduce a correlation among the parameters searched so that correct and sufficiently precise determination of parameter values is achieved. Since the presence and properties of the defects are difficult to control independently by tuning of the deposition conditions, the optimization does not in general involve the elimination of defects. Instead they are taken into account in the design of the film systems. The outlined approach is demonstrated on the characterization and optimization of ultraviolet antireflective coating formed by double layer of Al2O3 and MgF2 deposited on fused silica.

  3. Terahertz filter integrated with a subwavelength structured antireflection coating

    NASA Astrophysics Data System (ADS)

    Woo, Jeong Min; Kim, Dae-Seon; Kim, Dong-Ju; Jang, Jae-Hyung

    2015-12-01

    Micro-pyramid shaped subwavelength structures (SWSs) were integrated on both sides of a terahertz (THz) filter by means of stamping methods. Two silicon-based stamping molds fabricated via crystallographic wet etching were utilized to replicate SWSs onto cyclo-olefin copolymer (COC) films coated onto both sides of a THz filter at the same time. The SWSs act as an broadband antireflection coating to reduce the surface reflection loss in a frequency range of 0.2 THz to 1.4 THz. Compared to a THz filter without SWSs, the filter integrated with double-sided SWSs exhibits a low standing wave ratio inside the substrate and THz signal transmission enhancement of up to 10.8%.

  4. Contamination-resistant silica antireflective coating with closed ordered mesopores.

    PubMed

    Sun, Jinghua; Zhang, Qinghua; Ding, Ruimin; Lv, Haibing; Yan, Hongwei; Yuan, Xiaodong; Xu, Yao

    2014-08-21

    Porous silica optical antireflective (AR) coatings prepared by traditional sol-gel method have been extensively used for high power laser systems, but a serious drawback is that contamination existing in the high vacuum is easily absorbed by the disordered open pore structure, resulting in a fast decrease in transmittance. To improve the stability of transmittance in vacuum, a contamination-resistant silica AR coating with ordered mesopores completely closed by hydrophobic-oleophobic groups was successfully developed on a fused quartz substrate. The ordered mesopores in the coating were controlled under the direction of surfactant F127 via an evaporation-induced-self-assembling process and then were closed by post-grafting long chain fluoroalkylsilane. The grazing incidence small angle X-ray scattering (GISAXS) and the X-ray reflectivity (XRR) results indicated that the mesopores in the coating constructed a Fmmm orthorhombic symmetry structure with a (010) plane parallel to the substrate. Cage-like mesopores were confirmed by nitrogen adsorption-desorption analysis. The obtained coatings showed low surface roughness, excellent abrase-resistance and high transmittance of 100% on quartz substrate. Especially, the decrease of transmittance tested with polydimethylsiloxane pollution in vacuum within one-month was as small as 0.02%. The laser induced damage threshold was up to 59.8 J cm(-2) at a 12 ns laser pulse of 1053 nm wavelength. This work provides an alternative way to fabricate AR coatings with high stability.

  5. Improvement of OLED properties with anti-reflection coatings

    NASA Astrophysics Data System (ADS)

    Liu, Chunling; Wang, Dongmei; Zhao, Lei; Jiang, Wenlong; Qin, Zhengkun; Wang, Chunwu

    2010-11-01

    An anti-reflection (AR) coating system was inserted between the anode (ITO) and the glass substrate in the red light organic electroluminescent devices (OLED) for the structure being K9/ITO/NPB (60nm)/DCJTB (0.3nm)/Alq3 (60nm)/ LiF(0.3nm)/Al. The AR film system structure was K9/TiO2/Al2O3/2-ITO, and the optical thicknesses of TiO2 and Al2O3 coatings were also quarter wave length. The results indicated that the maximum transmissivity of AR coating was by 95 %( 610nm); it increased by 8% compared with only using ITO as AR coating. The average luminance increased by about 30%, the average energy efficiency increased by about 60%, while reducing the threshold voltage of the devices. The processing is simple and high efficient, and can change AR coating structure according to the OLED device different emission wavelength, therefore, can be widely applied to the OLED devices.

  6. Antireflective graded index silica coating, method for making

    DOEpatents

    Yoldas, Bulent E.; Partlow, Deborah P.

    1985-01-01

    Antireflective silica coating for vitreous material is substantially non-reflecting over a wide band of radiations. This is achieved by providing the coating with a graded degree of porosity which grades the index of refraction between that of air and the vitreous material of the substrate. To prepare the coating, there is first prepared a silicon-alkoxide-based coating solution of particular polymer structure produced by a controlled proportion of water to alkoxide and a controlled concentration of alkoxide to solution, along with a small amount of catalyst. The primary solvent is alcohol and the solution is polymerized and hydrolized under controlled conditions prior to use. The prepared solution is applied as a film to the vitreous substrate and rapidly dried. It is thereafter heated under controlled conditions to volatilize the hydroxyl radicals and organics therefrom and then to produce a suitable pore morphology in the residual porous silica layer. The silica layer is then etched in order to enlarge the pores in a graded fashion, with the largest of the pores remaining being sufficiently small that radiations to be passed through the substrate are not significantly scattered. For use with quartz substrates, extremely durable coatings which display only 0.1% reflectivity have been prepared.

  7. Improved antireflection coated microspheres for biological applications of optical tweezers

    NASA Astrophysics Data System (ADS)

    Ferro, Valentina; Sonnberger, Aaron; Abdosamadi, Mohammad K.; McDonald, Craig; Schäffer, Erik; McGloin, David

    2016-09-01

    The success of optical tweezers in cellular biology1 is in part due to the wide range of forces that can be applied, from femto- to hundreds of pico-Newtons; nevertheless extending the range of applicable forces to the nanoNewton regime opens access to a new set of phenomena that currently lie beyond optical manipulation. A successful approach to overcome the conventional limits on trapping forces involves the optimization of the trapped probes. Jannasch et al.2 demonstrated that an anti-reflective shell of nanoporous titanium dioxide (aTiO2, nshell = 1.75) on a core particle made out of titanium dioxide in the anatase phase (cTiO2, ncore = 2.3) results in trappable microspheres capable to reach forces above 1 nN. Here we present how the technique can be further improved by coating the high refractive index microspheres with an additional anti-reflective shell made out of silica (SiO2). This external shell not only improves the trap stability for microspheres of different sizes, but also enables the use of functionalization techniques already established for commercial silica beads in biological experiments. We are also investigating the use of these new microspheres as probes to measure adhesion forces between intercellular adhesion molecule 1 (ICAM-1) and lymphocyte function-associated antigen 1 (LFA-1) in effector T-Cells and will present preliminary results comparing standard and high-index beads.

  8. Design of antireflective nanostructures and optical coatings for next-generation multijunction photovoltaic devices.

    PubMed

    Perl, Emmett E; McMahon, William E; Bowers, John E; Friedman, Daniel J

    2014-08-25

    The successful development of multijunction photovoltaic devices with four or more subcells has placed additional importance on the design of high-quality broadband antireflection coatings. Antireflective nanostructures have shown promise for reducing reflection loss compared to the best thin-film interference coatings. However, material constraints make nanostructures difficult to integrate without introducing additional absorption or electrical losses. In this work, we compare the performance of various nanostructure configurations with that of an optimized multilayer antireflection coating. Transmission into a four-junction solar cell is computed for each antireflective design, and the corresponding cell efficiency is calculated. We find that the best performance is achieved with a hybrid configuration that combines nanostructures with a multilayer thin-film optical coating. This approach increases transmitted power into the top subcell by 1.3% over an optimal thin-film coating, corresponding to an increase of approximately 0.8% in the modeled cell efficiency.

  9. Nanowire-based multifunctional antireflection coatings for solar cells.

    PubMed

    Hiralal, Pritesh; Chien, Chihtao; Lal, Niraj N; Abeygunasekara, Waranatha; Kumar, Abhishek; Butt, Haider; Zhou, Hang; Unalan, Husnu Emrah; Baumberg, Jeremy J; Amaratunga, Gehan A J

    2014-11-06

    Organic (P3HT/PCBM) solar cells are coated with ZnO nanowires as antireflection coatings and show up to 36% enhancement in efficiency. The improvement is ascribed to an effective refractive index which results in Fabry-Perot absorption bands which match the polymer band-gap. The effect is particularly pronounced at high light incidence angles. Simultaneously, the coating is used as a UV-barrier, demonstrating a 50% reduction in the rate of degradation of the polymers under accelerated lifetime testing. The coating also allows the surface of the solar cell to self-clean via two distinct routes. On one hand, photocatalytic degradation of organic material on ZnO is enhanced by the high surface area of the nanowires and quantified by dye degradation measurements. On the other, the surface of the nanowires can be functionalized to tune the water contact angle from superhydrophilic (16°) to superhydrophobic (152°), resulting in self-cleaning via the Lotus effect. The multifunctional ZnO nanowires are grown by a low cost, low temperature hydrothermal method, compatible with process limitations of organic solar cells.

  10. Adhesion of Antireflective Coatings in Multijunction Photovoltaics: Preprint

    SciTech Connect

    Brock, Ryan; Dauskardt, Reinhold H.; Miller, David C.

    2016-06-16

    The development of a new composite dual cantilever beam (cDCB) thin-film adhesion testing method is reported, which allows the measurement of adhesion on the fragile thin substrates used in multijunction photovoltaics. We address the adhesion of several antireflective coating systems on multijunction cells. By varying interface chemistry and morphology, we demonstrate the ensuing effects on adhesion and help to develop an understanding of how high adhesion can be achieved, as adhesion values ranging from 0.5 J/m2 to 10 J/m2 were measured. Damp Heat (85 degrees C/85% RH) was used to invoke degradation of interfacial adhesion. We show that even with germanium substrates that fracture easily, quantitative measurements of adhesion can still be made at high test yield. The cDCB test is discussed as an important new methodology, which can be broadly applied to any system that makes use of thin, brittle, or otherwise fragile substrates.

  11. Optimization of multilayer antireflection coating for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Sikder, Urmita; Zaman, Mohammad Asif

    2016-05-01

    Multilayer antireflection coating (ARC) for photovoltaics is optimized using Differential Evolution (DE) algorithm. A general transfer-matrix based mathematical formulation is used for evaluating reflection spectra of the system. Exact and complete values of refractive indices are used in the analysis to provide higher accuracy of the results. The proposed optimization method takes into account the solar irradiance spectra, absorption characteristics of semiconductors and angle of incidence to maximize efficiency. This method is found to reduce the average reflectance for a wide range of angles of incidence. The proposed method is used to design ARC for silicon solar cell and a multi-junction AlGaAs/GaAs/Ge solar cell. Finally, comparative analysis of different ARC designs is provided in terms of corresponding solar cell characteristics.

  12. Durability testing of antireflection coatings for solar applications

    NASA Astrophysics Data System (ADS)

    Jorgensen, Gary J.; Brunold, Stefan; Koehl, Michael; Nostell, Per; Oversloot, Henk; Roos, Arne

    1999-10-01

    Antireflection (AR) coatings can be incorporated into highly transmitting glazings that, depending upon their cost, performance, and durability of optical properties, can be economically viable in solar collectors, agricultural greenhouses, and PV systems. A number of AR-coated glazings have been prepared under the auspices of the International Energy Agency Working Group on Durability of Materials for Solar Thermal Collectors. The AR coatings are of two types, including (1) various sol-gels applied to glass and (2) an embossed treatment of sheet acrylic. Typically, for unweathered glazings, a 4 - 5% increase in solar-weighted transmittance has been achieved. For AR-coated glass, reflectance values as low as 0.5% - 0.7% at selected wavelengths (680 - 720 nm) were obtained. To determine the durability of the hemispherical transmittance, several collaborating countries are testing these materials both outdoors and in accelerated weathering chambers. All materials exposed outdoors are affixed to mini-collector boxes to simulate flat-plate collector conditions. Results for candidate AR coatings weathered at geographically disperse outdoor test sites exhibit changes in spectral transmittance primarily in the high visible range (600 - 700 nm). Accelerated testing at measured levels of simulated solar irradiance, and at different constant levels of temperature and relative humidity have been performed in different countries. Parallel testing with different levels of laboratory-controlled relevant stress factors permits the time-dependent performance of these materials to be compared with measured results from in-service outdoor exposure conditions. Coating adhesion and performance loss resulting from dirt and dust retention are also discussed.

  13. Antireflection coating standards of ophthalmic resin lens materials

    NASA Astrophysics Data System (ADS)

    Porden, Mark

    1991-12-01

    Current estimates of the percentage of anti-reflection coated lenses verses uncoated in the market today range from 3% in the United States (US.), to 60% in Europe, to 80% in Japan. Currently upwards of 80% of all prescription eyewear lenses dispensed are resin. Glass lenses lose market share yearly, as scratch resistant coatings on resin lenses are improved. Photochromic resin materials are also improving and will shortly equal the performance of glass photockromics. Until recently, the performance characteristics of ophthalmic lenses were divided into two schools. In Europe, the emphasis was on keeping the reflections to an absolute minimum, while in the Asian market the emphasis was on producing a lens, which had exceptional scratch resistance. A typical European lens may average .4% reflection across the visible spectrum (400 to 700 urn.), while the Asian lenses averaged in the 1.5% range. The growth ofAR coating in the U.S. 80 million pair a year total ophthalmic market has been lagging foreign markets for several reasons.

  14. Application of amorphous carbon based materials as antireflective coatings on crystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    da Silva, D. S.; Côrtes, A. D. S.; Oliveira, M. H.; Motta, E. F.; Viana, G. A.; Mei, P. R.; Marques, F. C.

    2011-08-01

    We report on the investigation of the potential application of different forms of amorphous carbon (a-C and a-C:H) as an antireflective coating for crystalline silicon solar cells. Polymeric-like carbon (PLC) and hydrogenated diamond-like carbon films were deposited by plasma enhanced chemical vapor deposition. Tetrahedral amorphous carbon (ta-C) was deposited by the filtered cathodic vacuum arc technique. Those three different amorphous carbon structures were individually applied as single antireflective coatings on conventional (polished and texturized) p-n junction crystalline silicon solar cells. Due to their optical properties, good results were also obtained for double-layer antireflective coatings based on PLC or ta-C films combined with different materials. The results are compared with a conventional tin dioxide (SnO2) single-layer antireflective coating and zinc sulfide/magnesium fluoride (ZnS/MgF2) double-layer antireflective coatings. An increase of 23.7% in the short-circuit current density, Jsc, was obtained using PLC as an antireflective coating and 31.7% was achieved using a double-layer of PLC with a layer of magnesium fluoride (MgF2). An additional increase of 10.8% was obtained in texturized silicon, representing a total increase (texturization + double-layer) of about 40% in the short-circuit current density. The potential use of these materials are critically addressed considering their refractive index, optical bandgap, absorption coefficient, hardness, chemical inertness, and mechanical stability.

  15. Graded index antireflective coatings for glass. Second annual report

    SciTech Connect

    Haggerty, J.S.

    1980-05-01

    M.I.T. is conducting research which will lead to a process for forming broad band antireflective (AR) coatings on glass. Use of these coatings increases the extractable heat from flat-plate solar collectors by 30 to 50% compared with their performance under equivalent solar flux, surface temperature and ambient conditions without broad band AR coatings. Graded index surface films can virtually eliminate reflection losses if controlled properly. Graded index films on a borosilicate glass (Corning Glass Works No. 7740, Pyrex) has been demonstrated. While glass treated this way exhibited adequate optical properties, the glass itself, cannot be fabricated by the float glass process because of excessive working temperatures, and consequently is too expensive for solar applications. The objective of this work is to define glass compositions and processing steps which will result in graded index surface films (which exhibit broad band AR characteristics) on glasses which can be fabricated by the float glass process. The mechanism by which these graded index surface films are produced on glass surfaces consists of preferentially etching one phase from a phase separated glass. The film which remains consists of a porous structure in which the fraction of solid phase increases continuously from the free surface toward the bulk glass. Scattering effects are eliminated by limiting the size of the pore structure to dimensions which are substantially less than the wavelength of light. With this structure, the local index of refraction is proportional to the fraction of solid phase which is present. Characterizations are intended to define the microstructural and chemical nature of the surface film throughout its thickness. Progress is reported. (WHK)

  16. Quantitative adhesion characterization of antireflective coatings in multijunction photovoltaics

    SciTech Connect

    Brock, Ryan; Rewari, Raunaq; Novoa, Fernando D.; Hebert, Peter; Ermer, James; Miller, David C.; Dauskardt, Reinhold H.

    2016-08-01

    We discuss the development of a new composite dual cantilever beam (cDCB) thin-film adhesion testing method, which enables the quantitative measurement of adhesion on the thin and fragile substrates used in multijunction photovoltaics. In particular, we address the adhesion of several 2- and 3-layer antireflective coating systems on multijunction cells. By varying interface chemistry and morphology through processing, we demonstrate the marked effects on adhesion and help to develop an understanding of how high adhesion can be achieved, as adhesion values ranging from 0.5 J/m2 to 10 J/m2 were measured. Damp heat (85 degrees C/85% RH) was used to invoke degradation of interfacial adhesion. We demonstrate that even with germanium substrates that fracture relatively easily, quantitative measurements of adhesion can be made at high test yield. The cDCB test is discussed as an important new methodology, which can be broadly applied to any system that makes use of thin, brittle, or otherwise fragile substrates.

  17. Nanostructured Anti-Reflecting and Water-Repellent Surface Coatings

    ScienceCinema

    None

    2016-11-23

    A nanotechnology-based surface-texturing method developed at Brookhaven Lab’s Center for Functional Nanomaterials imparts perfect anti-reflection and robust water-repellency to silicon, glass, and some plastics.

  18. Nanostructured Anti-Reflecting and Water-Repellent Surface Coatings

    SciTech Connect

    2016-11-08

    A nanotechnology-based surface-texturing method developed at Brookhaven Lab’s Center for Functional Nanomaterials imparts perfect anti-reflection and robust water-repellency to silicon, glass, and some plastics.

  19. Anti-reflective and anti-soiling coatings with self-cleaning properties

    SciTech Connect

    Nair, Vinod; Brophy, Brenor L.

    2016-10-04

    Disclosed herein is a coated glass element including a glass component and a coating adhered to the glass component through siloxane linkages, the coating having at least one of an anti-reflective property, a high abrasion resistance property and a hydrophobic property, wherein the coating comprises a dried gel formed from at least one hydrolyzed alkoxysilane-based sol and at least one hydrolyzed organosilane-based sol.

  20. Design of multilayer antireflection coatings made from co-sputtered and low-refractive-index materials by genetic algorithm.

    PubMed

    Schubert, Martin F; Mont, Frank W; Chhajed, Sameer; Poxson, David J; Kim, Jong Kyu; Schubert, E Fred

    2008-04-14

    Designs of multilayer antireflection coatings made from co-sputtered and low-refractive-index materials are optimized using a genetic algorithm. Co-sputtered and low-refractive-index materials allow the fine-tuning of refractive index, which is required to achieve optimum anti-reflection characteristics. The algorithm minimizes reflection over a wide range of wavelengths and incident angles, and includes material dispersion. Designs of antireflection coatings for silicon-based image sensors and solar cells, as well as triple-junction GaInP/GaAs/Ge solar cells are presented, and are shown to have significant performance advantages over conventional coatings. Nano-porous low-refractive-index layers are found to comprise generally half of the layers in an optimized antireflection coating, which underscores the importance of nano-porous layers for high-performance broadband and omnidirectional antireflection coatings.

  1. Effects of positive ion implantation into antireflection coating of silicon solar cells

    NASA Technical Reports Server (NTRS)

    Middleton, A. E.; Harpster, J. W.; Collis, W. J.; Kim, C. K.

    1971-01-01

    The state of technological development of Si solar cells for highest obtained efficiency and radiation resistance is summarized. The various theoretical analyses of Si solar cells are reviewed. It is shown that factors controlling blue response are carrier diffusion length, surface recombination, impurity concentration profile in surface region, high level of surface impurity concentration (degeneracy), reflection coefficient of oxide, and absorption coefficient of Si. The theory of ion implantation of charge into the oxide antireflection coating is developed and side effects are discussed. The experimental investigations were directed at determining whether the blue response of Si solar cells could be improved by phosphorus ion charges introduced into the oxide antireflection coating.

  2. Enhanced photocurrent in crystalline silicon solar cells by hybrid plasmonic antireflection coatings

    NASA Astrophysics Data System (ADS)

    Fahim, Narges F.; Ouyang, Zi; Jia, Baohua; Zhang, Yinan; Shi, Zhengrong; Gu, Min

    2012-12-01

    Photocurrent enhancement induced by plasmonic light trapping is of great interest for photovoltaics. We design and demonstrate hybrid plasmonic antireflection coatings as an efficient light trapping strategy for broadband absorption and photocurrent enhancement in crystalline silicon solar cells. Gold nanoparticles of size ranging from 15 to 150 nm are embedded in standard SiNx antireflection coatings with a thickness of 90 nm. Through optimizing the location of tailored nanoparticles within the SiNx layer, both light scattering enhancement and near-field light concentration can be harnessed. A maximum increase of 6.3% in photocurrent is achieved for textured multi-crystalline Si solar cells with the optimum configuration.

  3. Anti-reflection coating of Cerium oxide on a plastic substrate

    NASA Astrophysics Data System (ADS)

    Kang, Hyunil; Choi, Wonseok; Kim, Doyoung

    2015-01-01

    Cerium oxide (CeO2) films are suitable for use as anti-reflective coatings for display panels, touch screens, and silicon solar cells. The CeO2 films grown by using a reactive radio frequency sputtering method under various deposition conditions was investigated. The CeO2 films were deposited at room temperature because the plastic substrate was too weak for use at higher temperatures. The films exhibited a strong (111) preferred orientation with properties varying as a function of the process conditions. We present the properties of CeO2 anti-reflective coatings on plastic substrates.

  4. Anti-reflective and anti-soiling coatings for self-cleaning properties

    DOEpatents

    Brophy, Brenor L.; Nair, Vinod; Dave, Bakul Champaklal

    2016-05-31

    The disclosure discloses abrasion resistant, persistently hydrophobic and oleophobic, anti-reflective and anti-soiling coatings for glass. The coatings described herein have wide application, including for example the front cover glass of solar modules. Methods of applying the coatings using various apparatus are disclosed. Methods for using the coatings in solar energy generation plants to achieve greater energy yield and reduced operations costs are disclosed. Coating materials are formed by combinations of hydrolyzed silane-base precursors through sol-gel processes. Several methods of synthesis and formulation of coating materials are disclosed.

  5. Tuning the peak position of subwavelength silica nanosphere broadband antireflection coatings.

    PubMed

    Tao, Fei; Hiralal, Pritesh; Ren, Lianbing; Wang, Yong; Dai, Qing; Amaratunga, Gehan Aj; Zhou, Hang

    2014-01-01

    Subwavelength nanostructures are considered as promising building blocks for antireflection and light trapping applications. In this study, we demonstrate excellent broadband antireflection effect from thin films of monolayer silica nanospheres with a diameter of 100 nm prepared by Langmuir-Blodgett method on glass substrates. With a single layer of compact silica nanosphere thin film coated on both sides of a glass, we achieved maximum transmittance of 99% at 560 nm. Furthermore, the optical transmission peak of the nanosphere thin films can be tuned over the UV-visible range by changing processing parameters during Langmuir-Blodgett deposition. The tunable optical transmission peaks of the Langmuir-Blodgett films were correlated with deposition parameters such as surface pressure, surfactant concentration, ageing of suspensions and annealing effect. Such peak-tunable broadband antireflection coating has wide applications in diversified industries such as solar cells, windows, displays and lenses.

  6. Antireflective coatings on Fresnel lenses by spin-coating of solid silica nanoparticles.

    PubMed

    Zhou, Gang; He, Junhui

    2013-08-01

    Antireflective (AR) coatings were fabricated from solid silica nanoparticles (SNPs) of ca. 16 nm in size on Fresnel lenses via one-step spin coating without any high temperature treatment. Transmission electron microscopy was used to observe the morphology and structure of the SNPs. Transmission spectra were recorded on a UV-vis-NIR spectrophotometer. The results indicated that Fresnel lenses covered with the SNPs coatings were much more transparent than the uncoated Fresnel lens. The maximum transmittance of the coated Fresnel lenses reached as high as 99.8%, whereas that of the uncoated Fresnel lens is only 94.3%. Surface wettability was studied by a contact angle/interface system, and the results indicated that the coatings on Fresnel lenses were more hydrophilic than the uncoated Fresnel lens. The surface morphologies and structures of the coatings were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The mechanical robustness of the coatings was examined by pencil scratch tests and attenuated total reflection infrared spectroscopy (ATR-IR).

  7. Sol-gel broadband antireflective coatings for advanced laser-glass amplifiers

    NASA Astrophysics Data System (ADS)

    Floch, Herve G.; Belleville, Philippe F.; Pegon, Philippe M.

    1994-10-01

    The cost of a large laser system is a strong function of the overall electrical to final photon efficiency. To improve the stored energy and therefore the pumping efficiency of sophisticated and costly laser-glass amplifiers, we have developed a novel two-layer broadband antireflective coating for the blast-shield component. The blast-shield is an optic placed between the flashlamps and the laser disk amplifiers to prevent damage of laser disks by possible explosion of a flashlamp. The sol-gel antireflective coating was dip-coated at room temperature onto 8-cm diameter glass samples. The coating basically consisted of a halfwave- thick high-index material such as ZrO2-PVP (PolyVinyl Pyrrolidone) and a quarterwave- thick low-index material such as SiO2-siloxane. To improve the abrasion resistance of the coated part, a lubricating and water-repellent material was applied as a very thin overcoat. In addition to a 6.5 to 7.2% transmission gain over the spectrum of interest, the coating was moderately abrasion resistant and chemically durable. Flashlamp-induced damage to the antireflective coating for 1000 glow discharges at 10 to 12 J/cm2 were minimal and similar to uncoated parts.

  8. Anti-reflection coatings applied by acid-leaching process. Final report

    SciTech Connect

    Pastirik, E.

    1980-09-01

    The Magicote C process developed by S.M. Thompsen was evaluated for use in applying an antireflective coating to the cover plates of solar cell panels. The process uses a fluosilicic acid solution supersaturated with silica at elevated temperature to selectively attack the surface of soda-lime glass cover plates and alter the physical and chemical composition of a thin layer of glass. The altered glass layer constitutes an antireflective coating. The process produces coatings of excellent optical quality which possess outstanding resistance to soiling and staining. The coatings produced are not resistant to mechanical abrasion and are attacked to some extent by glass cleansers. Control of the filming process was found to be difficult.

  9. Moth eye antireflection coated GaInP/GaAs/GaInNAs solar cell

    NASA Astrophysics Data System (ADS)

    Aho, Arto; Tommila, Juha; Tukiainen, Antti; Polojärvi, Ville; Niemi, Tapio; Guina, Mircea

    2014-09-01

    The performance of a GaInP/GaAs/GaInNAs solar cell incorporating AlInP moth eye antireflection coating is reported and compared with the performance of a similar cell comprising TiO2/SiO2 antireflection coating. The moth eye coating exhibits an average reflectance of only 2% within the spectral range from 400 nm to 1600 nm. EQE measurements revealed absorption-related losses in the AlInP moth eye coating at wavelengths below 510 nm. Short wavelength absorption decreases the current generation in the top GaInP junction by 10%. Despite the absorption losses, the moth eye patterned GaInP/GaAs/GaInNAs solar cell exhibited higher current generation under AM1.5G real sun illumination.

  10. Robust antifogging antireflective coatings on polymer substrates by hydrochloric acid vapor treatment.

    PubMed

    Li, Tong; He, Junhui; Yao, Lin; Geng, Zhi

    2015-04-15

    Antireflective coatings on polymer substrates have received significant attention for their potential applications. In this paper, robust microporous antifogging antireflective coatings on polymer substrates were prepared from acid-catalyzed silica sol followed by hydrochloric acid vapor solidification at mild temperature below glass transition temperatures of common polymers. The coatings passed 3H pencil hardness test, sand flow test and water-drop test. They had excellent antireflective and antifogging properties. The maximum transmittance of coatings on PMMA substrates reached 100.0% (the maximum transmittance wavelength could be regulated) and average transmittance reached 99.0% in 400-800 nm. The advantage and mechanism of hydrochloric acid vapor solidification and mechanical strength enhancement of coatings are discussed in contrast to ammonia vapor treatment and air vapor treatment. The hydrochloric acid vapor treatment results in a dense integrated microporous film structure. Optical properties were characterized by a UV-Vis spectrophotometer. Surface wettability was studied by a contact angle/interface system. Surface morphologies and structures of coatings were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atom force microscopy (AFM).

  11. Deep-ultraviolet antireflective coating with improved conformality, optical density, and etch rate

    NASA Astrophysics Data System (ADS)

    Guerrero, Douglas J.; Meador, James D.; Xu, Gu; Suzuki, Hitoshi; Sone, Yasuhisa; Krishnamurthy, Vandana N.; Claypool, James B.; Lamb, James E., III

    1998-06-01

    A new bottom antireflective coating (BARC) for 248 nm lithography is described. The new coating has an optical density of approximately 10/micrometers (k equals 0.41 and n equals 1.482) and plasma etches at rates higher than that of DUV resists depending on the etch conditions. Coating conformality is superior to older generation BARCs, also contributing to improved etch dynamics. Excellent 0.25 micrometers features have been obtained with ESCAP, Acetal and t-BOC type photoresists. The new BARC is spin coated from safe solvents and is spin bowl compatible with EBR and photoresist solvents.

  12. Technological peculiarities of deposition anti-reflective layers in low-e coatings

    NASA Astrophysics Data System (ADS)

    Yurjev, Y.; Sidelev, D.

    2013-12-01

    This article reports on the investigation of technological features magnetron sputtering for deposition anti-reflection layers in low-emission (low-e) coatings. The three-layer TiO2-Cu-TiO2 films were deposited by dual and planar magnetron sputtering systems (MS) on glass substrate. Studies of the current-voltage characteristics (CVC) and the hysteresis effect show that deposition of anti-reflection layers is possible in the transition mode with higher rates. For planar magnetron, the stability of electrical discharge parameters is achieved at 60 % O2 content in mixture. The calculations optical band gap Eg show that anti-reflective films have a rutile or anatase phases that depending on the content O2 in gas mixture. The optimum deposition conditions of TiO2 films were determined for all modifications of magnetrons. Anti-reflective layers, which are deposited by balanced dual MS, improve the transparency of low-e coatings (integral TVIS increase in 15%).

  13. 1059 and 1328nm LD pumped Nd:S-FAP solid state laser

    SciTech Connect

    Sun Lianke; Zhang Shaojun; Zhao Shengzhi; Wang Qingpu

    1996-12-31

    In this paper the authors introduce a new laser crystal--Nd{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F, Nd:S-FAP, and present its optical and physical characteristics. Based on the experiment lasing performance of CW LD pumped Nd:S-FAP crystal is reported here: the threshold and slope efficiency of 1059 nm Nd:S-FAP laser pumped by CW LD at 805nm are 7mW and 41%, and that of 1328nm Nd:S-FAP laser are 19mW and 35%. The comparison between experimental result and theoretical calculation is also discussed in this paper.

  14. Enhanced light extraction of Bi3Ge4O12 scintillator by graded-refractive-index antireflection coatings

    NASA Astrophysics Data System (ADS)

    Tong, Fei; Liu, Bo; Chen, Hong; Zhu, Zhichao; Gu, Mu

    2013-08-01

    A three-layer graded-refractive-index antireflection coating is designed and prepared on the one surface of the Bi3Ge4O12 scintillator by sol-gel technology. The emission intensity of the Bi3Ge4O12 with a graded-refractive-index antireflection coating exhibits a broadband and omnidirectional enhancement of 15.9% compared with the reference sample without coating. This significant enhancement is attributed to the decrease of Fresnel reflection, which is consistent with the measurement of transmission spectra. Additionally, it is evident that the graded-refractive-index coating is superior to the conventional quarter-wave coating due to the omnidirectionality advantage.

  15. Global sensitivity analysis of bandpass and antireflection coating manufacturing by numerical space filling designs.

    PubMed

    Vasseur, Olivier; Cathelinaud, Michel; Claeys-Bruno, Magalie; Sergent, Michelle

    2011-03-20

    We present the effectiveness of global sensitivity analyses of optical coatings manufacturing to assess the robustness of filters by computer experiments. The most critical interactions of layers are determined for a 29 quarter-wave layer bandpass filter and for an antireflection coating with eight non-quarter-wave layers. Two monitoring techniques with the associated production performances are considered, and their influence on the interactions classification is discussed. Global sensitivity analyses by numerical space filling designs give clues to improve filter manufacturing against error effects and to assess the potential robustness of the coatings.

  16. Fabrication of superhydrophilic and antireflective silica coatings on poly(methyl methacrylate) substrates

    SciTech Connect

    Geng, Zhi; He, Junhui; Xu, Ligang

    2012-06-15

    Graphical abstract: Self-cleaning and antireflection properties were successfully achieved by assembling (PDDA/S-20){sub n} coatings on PMMA substrates followed by oxygen plasma treatment. Highlights: ► Porous silica coatings were created by layer-by-layer assembly on PMMA substrates. ► Silica coatings were treated by oxygen plasma. ► Porous silica coatings were highly antireflective and superhydrophilic on PMMA substrates. -- Abstract: Silica nanoparticles of ca. 20 nm in size were synthesized, from which hierarchically porous silica coatings were fabricated on poly(methyl methacrylate) (PMMA) substrates via layer-by-layer (LbL) assembly followed by oxygen plasma treatment. These porous silica coatings were highly transparent and superhydrophilic. The maximum transmittance reached as high as 99%, whereas that of the PMMA substrate is only 92%. After oxygen plasma treatment, the time for a water droplet to spread to a contact angle of lower than 5° decreased to as short as 0.5 s. Scanning and transmission electron microscopy were used to observe the morphology and structure of nanoparticles and coating surfaces. Transmission and reflection spectra were recorded on UV–vis spectrophotometer. Surface wettability was studied by a contact angle/interface system. The influence of mesopores on the transmittance and wetting properties of coatings was discussed on the basis of experimental observations.

  17. Cicada-Wing-Inspired Self-Cleaning Antireflection Coatings on Polymer Substrates.

    PubMed

    Chen, Ying-Chu; Huang, Zhe-Sheng; Yang, Hongta

    2015-11-18

    The cicada has transparent wings with remarkable self-cleaning properties and high transmittance over the whole visible spectral range, which is derived from periodic conical structures covering the wing surface. Here we report a scalable self-assembly technique for fabricating multifunctional optical coatings that mimic cicada-wing structures. Spin-coated two-dimensional non-close-packed colloidal crystals are utilized as etching masks to pattern subwavelength-structured cone arrays directly on polymer substrates. The resulting gratings exhibit broadband antireflection performance and superhydrophobic properties after surface modification. The dependence of the cone shape and size on the antireflective and self-cleaning properties has also been investigated in this study.

  18. Broadband antireflection and field emission properties of TiN-coated Si-nanopillars

    NASA Astrophysics Data System (ADS)

    Chang, Yuan-Ming; Ravipati, Srikanth; Kao, Pin-Hsu; Shieh, Jiann; Ko, Fu-Hsiang; Juang, Jenh-Yih

    2014-07-01

    Broadband antireflection and field emission characteristics of silicon nanopillars (Si-NPs) fabricated by self-masking dry etching in hydrogen-containing plasma were systematically investigated. In particular, the effects of ultrathin (5-20 nm) titanium nitride (TiN) films deposited on Si-NPs by atomic layer deposition (ALD) on the optoelectronic properties were explored. The results showed that by coating the Si-NPs with a thin layer of TiN the antireflection capability of pristine Si-NPs can be significantly improved, especially in the wavelength range of 1000-1500 nm. The enhanced field emission characteristics of these TiN/Si-NP heterostructures suggest that, in addition to the reflectance suppression in the long wavelength range arising from the strong wavelength-dependent refractive index of TiN, the TiN-coating may have also significantly modified the effective work function at the TiN/Si interface as well.

  19. UV testing of solar cells: Effects of antireflective coating, prior irradiation, and UV source

    NASA Technical Reports Server (NTRS)

    Meulenberg, A.

    1993-01-01

    Short-circuit current degradation of electron irradiated double-layer antireflective-coated cells after 3000 hours ultraviolet (UV) exposure exceeds 3 percent; extrapolation of the data to 10(exp 5) hours (11.4 yrs.) gives a degradation that exceeds 10 percent. Significant qualitative and quantitative differences in degradation were observed in cells with double- and single-layer antireflective coatings. The effects of UV-source age were observed and corrections were made to the data. An additional degradation mechanism was identified that occurs only in previously electron-irradiated solar cells since identical unirradiated cells degrade to only 6 +/- 3 percent when extrapolated 10(exp 5) hours of UV illumination.

  20. Combined Effects of Pyramid-Like Structures and Antireflection Coating on Si Solar Cell Efficiency.

    PubMed

    Cho, Chanseob; Oh, Junghwa; Lee, Byeungleul; Kim, Bonghwan

    2015-10-01

    We developed a novel process for synthesizing Si solar cells with improved efficiencies. The process involved the formation of pyramid-like structures on the Si substrate and the deposition and subsequent thermal annealing of an antireflection coating. The process consisted of three main stages. First, pyramid-like structures were textured on the Si substrate by reactive ion etching and subsequently etched using a mixture of HF, HNO3, and deionized water for 300 s. Next, an antireflection coating was deposited on the substrate and was subsequently thermally annealed in a furnace in a N2 atmosphere. After the annealing process, the minority carrier lifetime increased by approximately 40 μs. Further, because of the increase in the minority carrier lifetime and the uniform doping of the substrate, the leakage current decreased. As a result, the efficiency of resulting solar cell increased to 17.24%, in contrast to that of the reference cell, which was only 15.89%. Thus, uniform doping and the thermal annealing of the antireflective coating improved solar cell efficiency.

  1. Moisture resistant and anti-reflection optical coatings produced by plasma polymerization of organic compounds

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.

    1975-01-01

    The need for protective coatings on critical optical surfaces, such as halide crystal windows or lenses used in spectroscopy, has long been recognized. It has been demonstrated that thin, one micron, organic coatings produced by polymerization of flourinated monomers in low temperature gas discharge (plasma) exhibit very high degrees of moisture resistence, e.g., hundreds of hours protection for cesium iodide vs. minutes before degradation sets in for untreated surfaces. The index of refraction of these coatings is intermediate between that of the halide substrate and air, a condition for anti-reflection, another desirable property of optical coatings. Thus, the organic coatings not only offer protection, but improved transmittance as well. The polymer coating is non-absorbing over the range 0.4 to 40 microns with an exception at 8.0 microns, the expected absorption for C-F bonds.

  2. Single-Step Soft-Imprinted Large-Area Nanopatterned Antireflection Coating.

    PubMed

    van de Groep, Jorik; Spinelli, Pierpaolo; Polman, Albert

    2015-06-10

    We demonstrate an effective nanopatterned antireflection coating on glass that is based on sol-gel chemistry and large-area substrate-conformal soft-imprint technology. The printed 120 nm tall silica nanocylinders with a diameter of 245 nm in a square array with 325 nm pitch form an effective-index (n = 1.20) antireflection coating that reduces the double-sided reflection from a borosilicate glass slide from 7.35% to 0.57% (averaged over the visible spectral range) with a minimum reflectance <0.05% at 590 nm. The nanoglass coating is made using a simple process involving only spin-coating and an imprint step, without vacuum technology or annealing required. The refractive index of the nanoglass layers can be tailored over a broad range by controlling the geometry (1.002 < n < 1.44 in theory), covering a wide range that is not achievable with natural materials. We demonstrate that the nanoglass coating effectively eliminates glare from smart-phone display windows and significantly improves the efficiency of glass-encapsulated solar cells. These features, that are achieved over an angular range as wide as ±50°, together with strong hydrophobicity and mechanical durability, make nanoglass coatings a promising technology to improve the functionality of optoelectronic devices based on glass encapsulation.

  3. Ultraviolet degradation to double anti-reflective coated solar cells

    NASA Technical Reports Server (NTRS)

    Meulenberg, Andrew

    1992-01-01

    Six experiments at COMSAT Labs (since the early '80's) have consistently shown higher UV degradation rates for DAR coated cells when the tests are extended beyond 1000 hours. Results for degradation at 10 years, extrapolated from data at 3000 hours, exceeds 10%. Lesser degradation rates are observed for DAR coated textured cells. Data and models will be presented.

  4. Broad-bandwidth Metamaterial Antireflection Coatings for Sub-Millimeter Astronomy and CMB Foreground Removal

    NASA Astrophysics Data System (ADS)

    McMahon, Jeff

    Sub-millimeter observations are crucial for answering questions about star and galaxy formation; understanding galactic dust foregrounds; and for removing these foregrounds to detect the faint signature of inflationary gravitational waves in the polarization of the Cosmic Microwave Background (CMB). Achieving these goals requires improved, broad-band antireflection coated lenses and half-wave plates (HWPs). These optical elements will significantly boost the sensitivity and capability of future sub-millimeter and CMB missions. We propose to develop wide-bandwidth metamaterial antireflection coatings for silicon lenses and sapphire HWPs with 3:1 ratio bandwidth that are scalable across the sub-millimeter band from 300 GHz to 3 THz. This is an extension of our successful work on saw cut metamaterial AR coatings for silicon optics at millimeter wave lengths. These, and the proposed coatings consist of arrays of sub-wavelength scale features cut into optical surfaces that behave like simple dielectrics. We have demonstrated saw cut 3:1 bandwidth coatings on silicon lenses, but these coatings are limited to the millimeter wave band by the limitations of dicing saw machining. The crucial advance needed to extend these broad band coatings throughout the sub-millimeter band is the development of laser cut graded index metamaterial coatings. The proposed work includes developing the capability to fabricate these coatings, optimizing the design of these metamaterials, fabricating and testing prototype lenses and HWPs, and working with the PIPER collaboration to achieve a sub-orbital demonstration of this technology. The proposed work will develop potentially revolutionary new high performance coatings for the sub-millimeter bands, and cary this technology to TRL 7 paving the way for its use in space. We anticipate that there will be a wide range of applications for these coatings on future NASA balloons and satellites.

  5. Development of Anti-Reflection Coating Layer for Efficiency Enhancement of ZnO Dye-Sensitized Solar Cells.

    PubMed

    Chanta, E; Bhoomanee, C; Gardchareon, A; Wongratanaphisan, D; Phadungdhitidhada, S; Choopun, S

    2015-09-01

    In this research, we investigated the effects of ZnO anti-reflection coating layers on power conversion efficiency enhancement of ZnO dye-sensitized solar cells. ZnO thin films were prepared by rf-magnetron sputtering by varying sputtering time of 10, 30, 60, 80, 100 min. Surface morphology, thickness and optical reflective index were investigated by field emission scanning electron microscopy and ellipsometry. Then, transmittance and reflectance were investigated by UV-vis spectroscopy. Furthermore, we found that ZnO anti-reflection coating layers with sputtering time of 30 and 60 min showed lower reflection and higher transmission than that of reference film. In addition, ZnO anti-reflection coating layers have rough surface with sputtering rate has 2.14 nm/min. Thus, the ZnO anti-reflection coating layers with sputtering time in the range of 10-60 min have a potential as anti-reflection coating applications. The ZnO anti-reflection coating layers were used in ZnO dye-sensitized solar cells and exhibited a short circuit current density of 5.16 mA/cm2 and the maximum power conversion efficiency of 1.54% from a sample with sputtering time at 60 min while the reference cell exhibited 3.88 mA/cm2 and 1.19%, respectively. Thus, we suggested an alternative improvement of ZnO DSSCs by adding the ZnO anti-reflection coating layers.

  6. Characterization of 1064nm laser-induced damage on antireflection coatings grown by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Liu, Zhichao; Wei, Yaowei; Chen, Songlin; Luo, Jin; Ma, Ping

    2011-12-01

    Damage tests were carried out to measure the laser resistance of Al2O3/TiO2 and Al2O3/HfO2 antireflection coatings at 1064nm grown by atomic layer deposition (ALD). The S-on-1 and R-on-1 damage results are given. It's interesting to find that ALD coatings damage performance seems closed to those grown by conventional e-beam evaporation process. For Al2O3/TiO2 coatings, the grown temperature will impact the damage resistance of thin films. Crystallization of TiO2 layer at higher temperature could play an importance role as absorption defects that reduced the LIDT of coatings. In addition, it is found that using inorganic compound instead of organic compound as precursors for ALD process can effective prevent residual carbon in films and will increase the LIDT of coatings.

  7. Fabrication of broadband antireflection coating at terahertz frequency using a hot emboss method

    NASA Astrophysics Data System (ADS)

    Li, YunZhou; Cai, Bin; Zhu, YiMing

    2014-11-01

    We fabricated a terahertz anti-reflective structure on a polystylene by using a hot-embossing method. Polystylene was spin-coated onto a silicon substrate and then transformed by using a metallic mould comprising a bunch of Chinese acupuncture needles. The transformation layer yielded gradient refractive index profiles on the substrate which can reduce the surface reflection effectively. The samples were evaluated by a terahertz time-domain spectroscope. Compared with a bare silicon substrate, we observed an increase of ~30% in the transmittance. We also observed broader bandwidth properties compared with a single-layer antireflective structure. The process imposes no substrate limiting; i.e., it has great potential to be applied onto various THz devices.

  8. Fabrication of biomimetic high performance antireflective and antifogging film by spin-coating.

    PubMed

    Zhang, Liang; Lü, Changli; Li, Yunfeng; Lin, Zhe; Wang, Zhanhua; Dong, Heping; Wang, Tieqiang; Zhang, Xuemin; Li, Xiao; Zhang, Junhu; Yang, Bai

    2012-05-15

    In this paper, we report a facile way to fabricate biomimetic high performance optical hybrid films with excellent antireflective and antifogging properties by one-step spin-coating the mixture of mesoporous SiO(2) particles and SiO(2) sol. The production process of the films is easy, low-cost, and time-efficient. Mesoporous SiO(2) particles containing surfactants disperse in SiO(2) sol stably without any chemical modification, which decrease the effective refractive index and increase the transmittance of the films. In addition, such films possess superhydrophilic properties and exhibit high performance antifogging properties. Due to the good film forming performance of SiO(2) sol, mesoporous SiO(2) particles are embedded in the films and impart the films high mechanical stability and durability. The surface morphology of the films can maintain well after repeated friction, and the performances of antireflective and antifogging also do not change as well.

  9. Performance of antireflecting coating-AlGaAs window layer coupling for terrestrial concentrator GaAs solar cells

    SciTech Connect

    Valle, C.A. del; Alcaraz, M.F.

    1997-09-01

    In this paper, the authors present the performance of optical coating systems coupled with AlGaAs window layers over GaAs solar cells. Single, double, and triple antireflecting coatings and window layers with constant and graded aluminum content are considered. Comparison between constant and graded window layers is established. To better represent reality, practical factors such as absorption of materials even for antireflecting coatings and the oxidation at window layer surface due to its high aluminum content are also included in the calculations. The design criteria to determine the optimum thickness of each layer is the achievement of maximum photogenerated current density. For this purpose and to account for terrestrial concentrators GaAs solar cells, the inclusion of direct terrestrial solar spectrum together with the internal spectral response of the device are taken into account. Finally, the best antireflecting coating/AlGaAs window layer couplings for different cases are presented.

  10. Improving the laser-induced damage threshold of 532-nm antireflection coating using plasma ion cleaning

    NASA Astrophysics Data System (ADS)

    Zhu, Meiping; Xing, Huanbin; Chai, Yingjie; Yi, Kui; Sun, Jian; Wang, Jianguo; Shao, Jianda

    2017-01-01

    BK7 glass substrates were precleaned by different cleaning procedures before being loaded into a vacuum chamber, and then a series of plasma ion cleaning procedures were conducted at different bias voltages in the vacuum chamber, prior to the deposition of 532-nm antireflection (AR) coatings. The plasma ion cleaning process was implemented by the plasma ion bombardment from an advanced plasma source. The surface morphology of the plasma ion-cleaned substrate, as well as the laser-induced damage threshold (LIDT) of the 532-nm AR coating was investigated. The results indicated that the LIDT of 532-nm AR coating can be greatly influenced by the plasma ion cleaning energy. The plasma ion cleaning with lower energy is an attractive method to improve the LIDT of the 532-nm AR coating, due to the removal of the adsorbed contaminations on the substrate surface, as well as the removal of part of the chemical impurities hidden in the surface layer.

  11. High durability antireflection coatings for silicon and multispectral ZnS

    NASA Astrophysics Data System (ADS)

    Joseph, Shay; Marcovitch, Orna; Yadin, Ygal; Klaiman, Dror; Koren, Nitzan; Zipin, Hedva

    2007-04-01

    In the current complex battle field, military platforms are required to operate on land, at sea and in the air in all weather conditions both day and night. In order to achieve such capabilities, advanced electro-optical systems are being constantly developed and improved. These systems such as missile seeker heads, reconnaissance and target acquisition pods and tracking, monitoring and alert systems have external optical components (window or dome) which must remain operational even at extreme environmental conditions. Depending on the intended use of the system, there are a few choices of window and dome materials. Amongst the more common materials one can point out sapphire, ZnS, germanium and silicon. Other materials such as spinel, ALON and yittria may also be considered. Most infrared materials have high indices of refraction and therefore they reflect a large part of radiation. To minimize the reflection and increase the transmission, antireflection (AR) coatings are the most common choice. Since these systems operate at different environments and weather conditions, the coatings must be made durable to withstand these extreme conditions. In cases where the window or dome is made of relatively soft materials such as multispectral ZnS, the coating may also serve as protection for the window or dome. In this work, several antireflection coatings have been designed and manufactured for silicon and multispectral ZnS. The coating materials were chosen to be either oxides or fluorides which are known to have high durability. Ellipsometry measurements were used to characterize the optical constants of the thin films. The effects of the deposition conditions on the optical constants of the deposited thin films and durability of the coatings will be discussed. The coatings were tested according to MIL-STD-810E and were also subjected to rain erosion tests at the University of Dayton Research Institute (UDRI) whirling arm apparatus in which one of the coatings showed

  12. Performance of "Moth Eye" Anti-Reflective Coatings for Solar Cell Applications

    SciTech Connect

    Clark, E.; Kane, M.; Jiang, P.

    2011-03-14

    An inexpensive, effective anti-reflective coating (ARC) has been developed at the University of Florida to significantly enhance the absorption of light by silicon in solar cells. This coating has nano-scale features, and its microstructure mimics that of various night active insects (e.g. a moth's eye). It is a square array of pillars, each about 700 nm high and having a diameter of about 300 nm. Samples of silicon having this coating were exposed either to various combinations of either elevated temperature and humidity or to gamma irradiation ({sup 60}Co) at the Savannah River National Laboratory, or to a broad spectrum ultraviolet light and to a 532 nm laser light at the University of Florida. The anti-reflective properties of the coatings were unaffected by any of these environmental stresses, and the microstructure of the coating was also unaffected. In fact, the reflectivity of the gamma irradiated ARC became lower (advantageous for solar cell applications) at wavelengths between 400 and 1000 nm. These results show that this coating is robust and should be tested in actual systems exposed to either weather or a space environment. Structural details of the ARCs were studied to optimize their performance. Square arrays performed better than hexagonal arrays - the natural moth-eye coating is indeed a square array. The optimal depth of the templated nanopillars in the ARC was investigated. A wet etching technology for ARC formation was developed that would be less expensive and much faster than dry etching. Theoretical modeling revealed that dimple arrays should perform better than nipple arrays. A method of fabricating both dimple and nipple arrays having the same length was developed, and the dimple arrays performed better than the nipple arrays, in agreement with the modeling. The commercial viability of the technology is quite feasible, since the technology is scalable and inexpensive. This technology is also compatible with current industrial fabrication of

  13. Atomic Layer Deposition of Chemical Passivation Layers and High Performance Anti-Reflection Coatings on Back-Illuminated Detectors

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael E. (Inventor); Greer, Frank (Inventor); Nikzad, Shouleh (Inventor)

    2014-01-01

    A back-illuminated silicon photodetector has a layer of Al2O3 deposited on a silicon oxide surface that receives electromagnetic radiation to be detected. The Al2O3 layer has an antireflection coating deposited thereon. The Al2O3 layer provides a chemically resistant separation layer between the silicon oxide surface and the antireflection coating. The Al2O3 layer is thin enough that it is optically innocuous. Under deep ultraviolet radiation, the silicon oxide layer and the antireflection coating do not interact chemically. In one embodiment, the silicon photodetector has a delta-doped layer near (within a few nanometers of) the silicon oxide surface. The Al2O3 layer is expected to provide similar protection for doped layers fabricated using other methods, such as MBE, ion implantation and CVD deposition.

  14. Antireflective coatings for multijunction solar cells under wide-angle ray bundles.

    PubMed

    Victoria, Marta; Domínguez, César; Antón, Ignacio; Sala, Gabriel

    2012-03-26

    Two important aspects must be considered when optimizing antireflection coatings (ARCs) for multijunction solar cells to be used in concentrators: the angular light distribution over the cell created by the particular concentration system and the wide spectral bandwidth the solar cell is sensitive to. In this article, a numerical optimization procedure and its results are presented. The potential efficiency enhancement by means of ARC optimization is calculated for several concentrating PV systems. In addition, two methods for ARCs direct characterization are presented. The results of these show that real ARCs slightly underperform theoretical predictions.

  15. Optimized 2D array of thin silicon pillars for efficient antireflective coatings in the visible spectrum

    PubMed Central

    Proust, Julien; Fehrembach, Anne-Laure; Bedu, Frédéric; Ozerov, Igor; Bonod, Nicolas

    2016-01-01

    Light reflection occuring at the surface of silicon wafers is drastically diminished by etching square pillars of height 110 nm and width 140 nm separated by a 100 nm gap distance in a square lattice. The design of the nanostructure is optimized to widen the spectral tolerance of the antireflective coatings over the visible spectrum for both fundamental polarizations. Angle and polarized resolved optical measurements report a light reflection remaining under 5% when averaged in the visible spectrum for both polarizations in a wide angular range. Light reflection remains almost insensitive to the light polarization even in oblique incidence. PMID:27109643

  16. A novel approach to developer-soluble anti-reflective coatings for 248-nm lithography

    NASA Astrophysics Data System (ADS)

    Mercado, Ramil-Marcelo L.; Lowes, Joyce A.; Washburn, Carlton A.; Guerrero, Douglas J.

    2007-03-01

    A novel approach to developer-soluble bottom anti-reflective coatings (BARCs) for 248-nm lithography was demonstrated. The BARC formulations are photosensitive, dye-filled systems incorporated with a polymer binder. The films are generated by thermally crosslinking the polymer matrix, and are then photochemically decrosslinked in order to render them soluble in developer solutions. The BARCs are compatible with solvents commonly used in the industry. Easy modification of the films with regard to optical properties for potential use with various substrates was also demonstrated. The BARCs exhibit anisotropic development in aqueous tetramethylammonium hydroxide (TMAH) solutions subsequent to simulated photoresist application, exposure, and post-exposure bake.

  17. Development of processing procedures for advanced silicon solar cells. [antireflection coatings and short circuit currents

    NASA Technical Reports Server (NTRS)

    Scott-Monck, J. A.; Stella, P. M.; Avery, J. E.

    1975-01-01

    Ten ohm-cm silicon solar cells, 0.2 mm thick, were produced with short circuit current efficiencies up to thirteen percent and using a combination of recent technical advances. The cells were fabricated in conventional and wraparound contact configurations. Improvement in cell collection efficiency from both the short and long wavelengths region of the solar spectrum was obtained by coupling a shallow junction and an optically transparent antireflection coating with back surface field technology. Both boron diffusion and aluminum alloying techniques were evaluated for forming back surface field cells. The latter method is less complicated and is compatible with wraparound cell processing.

  18. Large integrated absorption enhancement in plasmonic solar cells by combining metallic gratings and antireflection coatings.

    PubMed

    Munday, Jeremy N; Atwater, Harry A

    2011-06-08

    We describe an ultrathin solar cell architecture that combines the benefits of both plasmonic photovoltaics and traditional antireflection coatings. Spatially resolved electron generation rates are used to determine the total integrated current improvement under AM1.5G solar illumination, which can reach a factor of 1.8. The frequency-dependent absorption is found to strongly correlate with the occupation of optical modes within the structure, and the improved absorption is mainly attributed to improved coupling to guided modes rather than localized resonant modes.

  19. Optimization of hybrid antireflection structure integrating surface texturing and multi-layer interference coating

    NASA Astrophysics Data System (ADS)

    Kubota, Shigeru; Kanomata, Kensaku; Suzuki, Takahiko; Hirose, Fumihiko

    2014-10-01

    The antireflection structure (ARS) for solar cells is categorized to mainly two different techniques, i.e., the surface texturing and the single or multi-layer antireflection interference coating. In this study, we propose a novel hybrid ARS, which integrates moth eye texturing and multi-layer coat, for application to organic photovoltaics (OPVs). Using optical simulations based on the finite-difference time-domain (FDTD) method, we conduct nearly global optimization of the geometric parameters characterizing the hybrid ARS. The proposed optimization algorithm consists of two steps: in the first step, we optimize the period and height of moth eye array, in the absence of multi-layer coating. In the second step, we optimize the whole structure of hybrid ARS by using the solution obtained by the first step as the starting search point. The methods of the simple grid search and the Hooke and Jeeves pattern search are used for global and local searches, respectively. In addition, we study the effects of deviations in the geometric parameters of hybrid ARS from their optimized values. The design concept of hybrid ARS is highly beneficial for broadband light trapping in OPVs.

  20. Anti-Reflective Coatings R&D for Next Generation Neutrinoless Double Beta Experiments

    NASA Astrophysics Data System (ADS)

    Leder, Alexander; Cuore Collaboration

    2016-03-01

    The Cyogenic Underground Observatory for Rare Events (CUORE) is a ton-scale cryogenic source=detector experiment designed to search for the Neutrinoless Double Beta Decay (0 νββ) of 130Te. CUORE currently utilizes a single phonon readout channel per crystal; adding a second channel for scintillation or Cherenkov light would improve particle identification for actively rejecting background events. This light would be collected via semiconductor wafers covered with anti-reflective coatings. These coatings maximize light absorption. In this talk, I will discuss the coating optimization regarding material and structure, and its implications for designing the next generation CUORE-style experiment. In addition, I will discuss projections for possible sensitivities of next generation 0 νββ searches that use dual channel light-phonon readouts.

  1. Deposition and spectral performance of an inhomogeneous broadband wide-angular antireflective coating

    NASA Astrophysics Data System (ADS)

    Janicki, V.; Gäbler, D.; Wilbrandt, S.; Leitel, R.; Stenzel, O.; Kaiser, N.; Lappschies, M.; Görtz, B.; Ristau, D.; Rickers, C.; Vergöhl, M.

    2006-10-01

    Gradient index coatings and optical filters are a challenge for fabrication. In a round-robin experiment, basically the same hybrid antireflection coating for the visible spectral region, combining homogeneous refractive index layers of pure materials and linear gradient refractive index layers of material mixtures, has been deposited. The experiment involved three different deposition techniques: electron-beam evaporation, ion-beam sputtering, and radio frequency magnetron sputtering. The material combinations used by these techniques were Nb2O5/SiO2, TiO2/SiO2, and Ta2O5/SiO2, respectively. The spectral performances of samples coated on one side and on both sides have been compared to the corresponding theoretical spectra of the designed profile. Also, the reproducibility of results for each process is verified. Finally, it is shown that ion-beam sputtering gave the best results in terms of deviation from the theoretical performance and reproducibility.

  2. Fluoride antireflection coatings for deep ultraviolet optics deposited by ion-beam sputtering.

    PubMed

    Yoshida, Toshiya; Nishimoto, Keiji; Sekine, Keiichi; Etoh, Kazuyuki

    2006-03-01

    Optically high quality coatings of fluoride materials are required in deep ultraviolet (DUV) lithography. We have applied ion-beam sputtering (IBS) to obtain fluoride films with smooth surfaces. The extinction coefficients were of the order of 10(-4) at the wavelength of 193 nm due to the reduction of their absorption loss. The transmittance of the MgF2/GdF3 antireflection coating was as high as 99.7% at the wavelength of 193 nm. The surfaces of the IBS deposited films were so smooth that the surface roughness of the A1F3/GdF3 film was comparable with that of the CaF2 substrate. The MgF2/GdF3 coating fulfilled the temperature and humidity requirements of military specification. Thus, the IBS deposited fluoride films are promising candidate for use in the DUV lithography optics.

  3. Deposition and spectral performance of an inhomogeneous broadband wide-angular antireflective coating.

    PubMed

    Janicki, V; Gäbler, D; Wilbrandt, S; Leitel, R; Stenzel, O; Kaiser, N; Lappschies, M; Görtz, B; Ristau, D; Rickers, C; Vergöhl, M

    2006-10-20

    Gradient index coatings and optical filters are a challenge for fabrication. In a round-robin experiment, basically the same hybrid antireflection coating for the visible spectral region, combining homogeneous refractive index layers of pure materials and linear gradient refractive index layers of material mixtures, has been deposited. The experiment involved three different deposition techniques: electron-beam evaporation, ion-beam sputtering, and radio frequency magnetron sputtering. The material combinations used by these techniques were Nb(2)O(5)/SiO(2), TiO(2)/SiO(2), and Ta(2)O(5)/SiO(2), respectively. The spectral performances of samples coated on one side and on both sides have been compared to the corresponding theoretical spectra of the designed profile. Also, the reproducibility of results for each process is verified. Finally, it is shown that ion-beam sputtering gave the best results in terms of deviation from the theoretical performance and reproducibility.

  4. Broadband Plasma-Sprayed Anti-reflection Coating for Millimeter-Wave Astrophysics Experiments

    NASA Astrophysics Data System (ADS)

    Jeong, O.; Lee, A.; Raum, C.; Suzuki, A.

    2016-08-01

    We have developed a plasma-sprayed anti-reflection (AR) coating technology for millimeter-wave astrophysics experiments with cryogenic optics which achieves minimal dissipative loss and broad bandwidth and is easily and accurately applied. Plasma spraying is a coating process through which melted or heated materials are sprayed onto a substrate. The dielectric constants of the plasma-sprayed coatings were tuned between 2.7 and 7.9 by mixing hollow ceramic microspheres with alumina powder as the base material and varying the plasma energy of the spray. By spraying low loss ceramic materials with a tunable dielectric constant, we can apply multiple layers of AR coating for broadband millimeter-wave detection. At 300 K, we achieved a fractional bandwidth of 106 over 90% transmission using a three-layer AR coating. Applying ceramic coatings on ceramic lenses offers an additional benefit of preventing cryogenic delamination of the coatings. We report on methodology of coating application and measurement of uniformity, repeatability, transmission property, and cryogenic adhesion performance.

  5. Characterization of Silicon Moth-Eye Antireflection Coatings for Astronomical Applications in the Infrared

    NASA Astrophysics Data System (ADS)

    Jeram, Sarik; Ge, Jian; Jiang, Peng; Phillips, Blayne

    2016-01-01

    Silicon moth-eye antireflective structures have emerged to be an excellent approachfor reducing the amount of light that is lost upon incidence on a given surface of optics made of silicon. This property has been exploited for a wide variety of products ranging from eyeglasses and flat-panel displays to solar panels. These materials typically come in the form of coatings that are applied to an optical substrate such as glass. Moth-eye coatings, made of a periodic array of subwavelength pillars on silicon substrates or other substrates, can produce the desired antireflection (AR) performance for a broad wavelength range and over a wide range of incident angles. In the field of astronomy, every photon striking a detector is significant - and thus, losses from reflectivity at the various optical interfaces before a detector can have significant implications to the science at hand. Moth-eye AR coatings on these optical interfaces may minimize their reflection losses while maximizing light throughput for a multitude of different astronomical instruments. In addition, moth-eye AR coatings, which are patterned directly on silicon surfaces, can significantly enhance the coating durability. At the University of Florida, we tested two moth-eye filters designed for use in the near-infrared regime at 1-8 microns by examining their optical properties, such as transmission, the scattered light, and wavefront quality, and testing the coatings at cryogenic temperatures to characterize their viability for use in both ground- and space-based infrared instruments. This presentation will report our lab evaluation results.

  6. Improved power conversion efficiency for dye-sensitized solar cells using a subwavelength-structured antireflective coating

    NASA Astrophysics Data System (ADS)

    Chou, Chun-Chi; Tsao, Kuan-Yi; Wu, Chih-Chung; Yang, Hongta; Chen, Chih-Ming

    2015-02-01

    Large-scale, subwavelength-structured nanodome arrays were successfully fabricated using simple, scalable bottom-up colloidal (nanosphere) lithography on a glass substrate as an efficient antireflective photoanode for dye-sensitized solar cells (DSSCs). A self-assembled monolayer of close-packed colloidal crystals (silica) was used as a structural template to pattern the two-dimensional subwavelength-structured nanodome arrays, which function as an efficient antireflective coating due to the graded refractive index across the interface between the air and specific nanodome array structure. The light harvesting for a DSSC with a subwavelength-structured antireflective coating was enhanced due to the improved broadband antireflectivity. Adjusting the nanodome size yielded a short-circuit current density (JSC) of 15.88 mA/cm2 with a power conversion efficiency (PCE) of 8.82%, which were both better than the reference cell without a subwavelength-structured antireflective coating (JSC = 15.26 mA/cm2 and PCE = 8.45%).

  7. Anti-Reflective Coating On Borosilicate Long Tubes Industrial Process And Quality Control

    NASA Astrophysics Data System (ADS)

    Eisenberg, N.; Ben-Dor, Y.; Warschawski, J. P.

    1989-07-01

    It has been shown that in order to improve the optical efficiency of a solar trough evacuated pipe used for Luz solar electricity generating systems, an appropriate low cost anti-reflective coating process should be implemented in the solar collector production line, and that a dip process is the optimal choice for this application. It is shown in this paper that pumping the coating solution out of the coating container rather than withdrawing the tubes is the most appropriate coating process for Luz's needs. The same method was employed for the second coating solution which was used both for mechanical abrasion resistance improvement and for increasing optical transmissivity. The measuring procedure for quality insurance of the coated tube was investigated thoroughly and an "in-house" technique, including solar simulation and spiral movement of the tested tube, was chosen in preference to the other standard procedures (spectrophotometry, reflectometry). The complete AR coating facility and production procedure is described and the results of the industrial process are analyzed.

  8. Low-cost and broadband terahertz antireflection coatings based on DMSO-doped PEDOT/PSS.

    PubMed

    Yan, Fei; Parrott, Edward P J; Liu, Xu Dong; Pickwell-MacPherson, Emma

    2015-06-15

    We report the potential application of 6% dimethylsulfoxide (DMSO)-doped poly (3, 4-ethylenedioxythiophene)/poly (4-styrenesulfonate) (PEDOT/PSS) as a low cost and broadband terahertz (THz) antireflection coating based on the impedance matching effect. The reflected pulses from the quartz and silicon substrates are observed to change with the thickness of the PEDOT/PSS layer. Theoretical analysis based on an equivalent transmission line circuit model and FDTD computational simulations have been used to understand the experimental results. Excellent impedance matching is achieved by a ∼39-nm-thick 6% DMSO-doped PEDOT/PSS layer on quartz, and a ∼101-nm-thick 6% DMSO-doped PEDOT/PSS layer on silicon due to the almost-frequency-independent conductivity of the thin film between 0.3 and 2.5 THz. In the critical conditions, the normalized main pulse transmission remains as high as 74% and 64%, for the quartz and silicon substrates, respectively, significantly higher than the existing state of the art THz antireflection coatings.

  9. Layer-by-layer-assembled high-performance broadband antireflection coatings.

    PubMed

    Shimomura, Hiroomi; Gemici, Zekeriyya; Cohen, Robert E; Rubner, Michael F

    2010-03-01

    Nanoparticles are indispensable ingredients of solution-processed optical, dielectric, and catalytic thin films. Although solution-based methods are promising low-cost alternatives to vacuum methods, they can have significant limitations. Coating uniformity, thickness control, roughness control, mechanical durability, and incorporation of a diverse set of functional organic molecules into nanoparticle thin films are major challenges. We have used the electrostatic layer-by-layer assembly technique to make uniform, conformal multistack nanoparticle thin films for optical applications with precise thickness control over each stack. Two particularly sought-after optical applications are broadband antireflection and structural color. The effects of interstack and surface roughness on optical properties of these constructs (e.g., haze and spectral response) have been studied quantitatively using a combination of Fourier-transform methods and atomic force microscopy measurements. Deconvoluting root-mean-square roughness into its large-, intermediate-, and small-scale components enables enhanced optical simulations. A 4-stack broadband antireflection coating (<0.5% average reflectance in the visible range, and 0.2% haze) composed of alternating high-index (n approximately 1.96) and low-index (n approximately 1.28) stacks has been made on glass substrate. Films calcinated at 550 degrees C endure a one-hour-long cloth cleaning test under 100 kPa normal stress.

  10. Recovery Act: A Low Cost Spray Deposited Solar PV Anti-Reflection Coating Final Technical Report

    SciTech Connect

    Harvey, Michael D.

    2010-08-30

    PV module glass is typically low iron glass which exhibits extremely low absorption of light at solar wavelengths. However, reflection losses from typical high quality solar glass are about 4.5% of the input solar energy. By applying an antireflection coating to the cover glass of their modules, a PV module maker will gain at least a 3% increase in the light passing through the glass and being converted to electricity. Thus achieving an increase of >3% in electricity output from the modules. This Project focussed on developing a process that deposits a layer of porous silica (SiO2) on glass or plastic components, and testing the necessary subcomponents and subsystems required to demonstrate the commercial technology. This porous layer acts as a broadband single layer AR coating for glass and plastics, with the added benefit of being a hydrophilic surface for low surface soiling.

  11. Self-assembled dual-sided hemispherical nano-dimple-structured broadband antireflection coatings

    NASA Astrophysics Data System (ADS)

    Lin, Cheng-Yen; Lin, Kun-Yi; Tsai, Hui-Ping; He, Yi-Xuan; Yang, Hongta

    2016-11-01

    A non-lithography-based approach is developed in this study for assembling monolayer close-packed hemispherical nano-dimple arrays on both sides of a PET film by a scalable Langmuir-Blodgett technology. The resulting gratings greatly suppress specular reflection and therefore enhance specular transmission for a broad range of visible wavelengths, resulting from a gradual change in the effective refractive index at air/PET interface. The experimental results reveal that the antireflection properties of the as-fabricated coatings are affected by the size of the nano-dimples. Moreover, both optical performances of single-sided and dual-sided nano-dimple-structured coatings have been investigated in this study.

  12. An anti-reflection coating for use with PMMA at 193 nm

    NASA Technical Reports Server (NTRS)

    Yen, Anthony; Smith, Henry I.; Schattenburg, M. L.; Taylor, Gary N.

    1992-01-01

    An antireflection coating (ARC) for use with poly(methyl methacrylate) (PMMA) resist for ArF excimer laser lithography (193 nm) was formulated. It consists of PMMA and a bis-azide, 4.4-prime-diazidodiphenyl sulfone (DDS) which crosslinks the film after deep UV (260 nm) irradiation and subsequent annealing. The reacted DDS then serves as the absorber for the 193 nm radiation and also prevents mixing of the ARC and PMMA during PMMA spin-coating and development. The effectiveness of the ARC was demonstrated by exposing, in PMMA, using achromatic holographic lithography, gratings of 100 nm period (about 50 nm linewidth) that are almost entirely free of an orthogonal standing wave.

  13. Antireflection Coating of TiO2 Study and Deposition by the Screen Printing Method

    NASA Astrophysics Data System (ADS)

    Boukennous, Y.; Benyahia, B.; Charif, M. R.; Chikouche, A.

    1995-08-01

    We are developing the Screen Printing technique for depositing a single layer quarter wavelength thick antireflection coating of titanium dioxide on silicon substrate. The ink is composed by the titanium ethoxide as the organometallic compound, terpineol as the solvent and the octyphenoxy polyethoxy as the vehicle. It has been applied to 4 inch polished silicon wafers, dried then fired and characterized. The objective of our work was to control the deposition parameters and the ink viscosity to determine their effects on the layer properties. The thicknesses of the TiO2 films were measured by the stylus technique using a Profilometer. AES, RBS and X-Ray diffraction are used to analyse the layer and to determine its structure and composition according to firing temperatures. The reflection coefficient is measured as a function of the wavelength. As a result, we obtain TiO2 coating thicknesses between 600 and 800 Å and a minimum reflection near 600nm.

  14. Effect of sol aging time on the anti-reflective properties of silica coatings templated with phosphoric acid

    NASA Astrophysics Data System (ADS)

    Wen, Wen; Li, Haibin; Chen, Xiaojing; Chang, Chengkang

    Silica anti-reflective coatings have been prepared by a sol-gel dip-coating process using the sol containing phosphoric acid as a pore-forming template. The effect of the aging time of the sol on the anti-reflective properties has been investigated. The surface topography of the silica AR coatings has been characterized. With increasing sol aging time, more over-sized pores larger than 100 nm are formed in the silica coatings. These could act as scattering centers, scattering visible light and thereby lowering transmittance. The optimal aging time was identified as 1 day, and the corresponding silica coatings showed a maximum transmittance of 99.2%, representing an 8% increase compared to the bare glass substrate.

  15. Anti-Reflective and Waterproof Hard Coating for High Power Laser Optical Elements

    NASA Astrophysics Data System (ADS)

    Murahara, Masataka; Yabe, Takashi; Uchida, Shigeaki; Yoshida, Kunio; Okamoto, Yoshiaki

    2006-05-01

    A hard coating method of single crystalline porous silica film is widely used for high power laser optical elements in the air. However, there is no protective hard coating method for the elements to survive high power laser irradiance while in the water. We, thus, developed a new method for a waterproof coating with photo-oxidation of silicone oil. The silicone oil was spin-coated onto the surface of optical elements, and then irradiated with a xenon excimer lamp in the air. In this treatment, a protective coating for plastic lenses, mirrors, and nonlinear optical crystals, which are highly deliquescent, was developed by taking advantage of the phenomenon in which organic silicone oil is transformed to inorganic amorphous glass by a process of photo-oxidation. This technique has enabled an optical thin coating film to transmit ultraviolet rays of wavelengths under 200 nm and possess the characteristics of homogeneity, high density, resistance to environment, anti-reflectiveness, resistance to water, and Mohs' scale of 5, which is comparable to apatite. This allows us to cool a slab laser head and use as a mirror for underwater laser welding.

  16. Large-aperture Wide-bandwidth Antireflection-coated Silicon Lenses for Millimeter Wavelengths

    NASA Technical Reports Server (NTRS)

    Datta, R.; Munson, C. D.; Niemack, M. D.; McMahon, J. J.; Britton, J.; Wollack, Edward J.; Beall, J.; Devlin, M. J.; Fowler, J.; Gallardo, P.; Hubmayr, J.; Irwin, K.; Newburgh, L.; Nibarger, J. P.; Page, L.; Quijada, Manuel A.; Schmitt, B. L.; Staggs, S. T.; Thornton, R.; Zhang, L.

    2013-01-01

    The increasing scale of cryogenic detector arrays for submillimeter and millimeter wavelength astrophysics has led to the need for large aperture, high index of refraction, low loss, cryogenic refracting optics. Silicon with n 3.4, low loss, and high thermal conductivity is a nearly optimal material for these purposes but requires an antireflection (AR) coating with broad bandwidth, low loss, low reflectance, and a matched coefficient of thermal expansion. We present an AR coating for curved silicon optics comprised of subwavelength features cut into the lens surface with a custom three-axis silicon dicing saw. These features constitute a metamaterial that behaves as a simple dielectric coating.We have fabricated silicon lenses as large as 33.4 cm in diameter with micromachined layers optimized for use between 125 and 165 GHz. Our design reduces average reflections to a few tenths of a percent for angles of incidence up to 30deg with low cross polarization.We describe the design, tolerance, manufacture, and measurements of these coatings and present measurements of the optical properties of silicon at millimeter wavelengths at cryogenic and room temperatures. This coating and lens fabrication approach is applicable from centimeter to submillimeter wavelengths and can be used to fabricate coatings with greater than octave bandwidth.

  17. Monolithic graded-refractive-index glass-based antireflective coatings. Broadband/omnidirectional light harvesting and self-cleaning characteristics

    DOE PAGES

    Aytug, Tolga; Lupini, Andrew R.; Jellison, Gerald E.; ...

    2015-04-23

    The design of multifunctional coatings impact impact the performance of many optical systems and components. Such coatings should be mechanically robust, and combine user-defined optical and wetting functions with scalable fabrication formulations. By taking cues from the properties of some natural biological structures, we report here the formation of low-refractive index antireflective glass films that embody omni-directional optical properties over a wide range of wavelengths, while also possessing specific wetting capabilities. The coatings comprise an interconnected network of nanoscale pores surrounded by a nanostructured silica framework. These structures result from a novel fabrication method that utilizes metastable spinodal phase separationmore » in glass-based materials. The approach not only enables design of surface microstructures with graded-index antireflection characteristics, where the surface reflection is suppressed through optical impedance matching between interfaces, but also facilitates self-cleaning ability through modification of the surface chemistry. Based on near complete elimination of Fresnel reflections (yielding >95% transmission through a single-side coated glass) and corresponding increase in broadband transmission, the fabricated nanostructured surfaces are found to promote a general and an invaluable ~3–7% relative increase in current output of multiple direct/indirect bandgap photovoltaic cells. Moreover, these antireflective surfaces also demonstrate superior resistance against mechanical wear and abrasion. Unlike conventional counterparts, the present antireflective coatings are essentially monolithic, enabling simultaneous realization of graded index anti-reflectivity, self-cleaning capability, and mechanical stability within the same surface. Moreover, the concept represents a fundamental basis for development of advanced coated optical quality products, especially where environmental exposure is required.« less

  18. Monolithic graded-refractive-index glass-based antireflective coatings. Broadband/omnidirectional light harvesting and self-cleaning characteristics

    SciTech Connect

    Aytug, Tolga; Lupini, Andrew R.; Jellison, Gerald E.; Joshi, Pooran C.; Ivanov, Ilia H.; Liu, Tao; Wang, Peng; Menon, Rajesh; Trejo, Rosa M.; Lara-Curzio, Edgar; Hunter, Scott R.; Simpson, John T.; Paranthaman, M. Parans; Christen, David K.

    2015-04-23

    The design of multifunctional coatings impact impact the performance of many optical systems and components. Such coatings should be mechanically robust, and combine user-defined optical and wetting functions with scalable fabrication formulations. By taking cues from the properties of some natural biological structures, we report here the formation of low-refractive index antireflective glass films that embody omni-directional optical properties over a wide range of wavelengths, while also possessing specific wetting capabilities. The coatings comprise an interconnected network of nanoscale pores surrounded by a nanostructured silica framework. These structures result from a novel fabrication method that utilizes metastable spinodal phase separation in glass-based materials. The approach not only enables design of surface microstructures with graded-index antireflection characteristics, where the surface reflection is suppressed through optical impedance matching between interfaces, but also facilitates self-cleaning ability through modification of the surface chemistry. Based on near complete elimination of Fresnel reflections (yielding >95% transmission through a single-side coated glass) and corresponding increase in broadband transmission, the fabricated nanostructured surfaces are found to promote a general and an invaluable ~3–7% relative increase in current output of multiple direct/indirect bandgap photovoltaic cells. Moreover, these antireflective surfaces also demonstrate superior resistance against mechanical wear and abrasion. Unlike conventional counterparts, the present antireflective coatings are essentially monolithic, enabling simultaneous realization of graded index anti-reflectivity, self-cleaning capability, and mechanical stability within the same surface. Moreover, the concept represents a fundamental basis for development of advanced coated optical quality products, especially where environmental exposure is required.

  19. The Broadband Anti-reflection Coated Extended Hemispherical Silicon Lenses for Polarbear-2 Experiment

    NASA Astrophysics Data System (ADS)

    Siritanasak, P.; Aleman, C.; Arnold, K.; Cukierman, A.; Hazumi, M.; Kazemzadeh, K.; Keating, B.; Matsumura, T.; Lee, A. T.; Lee, C.; Quealy, E.; Rosen, D.; Stebor, N.; Suzuki, A.

    2016-08-01

    Polarbear-2 (PB-2) is a next-generation receiver that is part of the Simons Array cosmic microwave background (CMB) polarization experiment which is located in the Atacama desert in Northern Chile. The primary scientific goals of the Simons Array are a deep search for the CMB B-mode signature of gravitational waves from inflation and the characterization of large-scale structure using its effect on CMB polarization. The PB-2 receiver will deploy with 1897 dual-polarization sinuous antenna-coupled pixels, each with a directly contacting extended hemispherical silicon lens. Every pixel has dual polarization sensitivity in two spectral bands centered at 95 and 150 GHz, for a total of 7588 transition edge sensor bolometers operating at 270 mK. To achieve the PB-2 detector requirements, we developed a broadband anti-reflection (AR) coating for the extended hemispherical lenses that uses two molds to apply two layers of epoxy, Stycast 1090 and Stycast 2850FT. Our measurements of the absorption loss from the AR coating on a flat surface at cryogenic temperatures show less than 1 % absorption, and the coating has survived multiple thermal cycles. We can control the diameter of the coating within 25 {\\upmu }m and translation errors are within 25 {\\upmu }m in all directions, which results in less than 1 % decrease in transmittance. We also find the performance of the AR-coated lens matches very well with simulations.

  20. Comparisons between laser damage and optical electric field behaviors for hafnia/silica antireflection coatings

    SciTech Connect

    Bellum, John; Kletecka, Damon; Rambo, Patrick; Smith, Ian; Schwarz, Jens; Atherton, Briggs

    2011-03-20

    We compare designs and laser-induced damage thresholds (LIDTs) of hafnia/silica antireflection (AR) coatings for 1054 nm or dual 527 nm/1054 nm wavelengths and 0 deg. to 45 deg. angles of incidence (AOIs). For a 527 nm/1054 nm, 0 deg. AOI AR coating, LIDTs from three runs arbitrarily selected over three years are {approx}20 J/cm{sup 2} or higher at 1054 nm and <10 J/cm{sup 2} at 527 nm. Calculated optical electric field intensities within the coating show two intensity peaks for 527 nm but not for 1054 nm, correlating with the lower (higher) LIDTs at 527 nm (1054 nm). For 1054 nm AR coatings at 45 deg. and 32 deg. AOIs and S and P polarizations (Spol and Ppol), LIDTs are high for Spol (>35 J/cm{sup 2}) but not as high for Ppol (>30 J/cm{sup 2} at 32 deg. AOI; {approx}15 J/cm{sup 2} at 45 deg. AOI). Field intensities show that Ppol discontinuities at media interfaces correlate with the lower Ppol LIDTs at these AOIs. For Side 1 and Side 2 dual 527 nm/1054 nm AR coatings of a diagnostic beam splitter at 22.5 deg. AOI, Spol and Ppol LIDTs (>10 J/cm{sup 2} at 527 nm; >35 J/cm{sup 2} at 1054 nm) are consistent with Spol and Ppol intensity behaviors.

  1. Antireflective disordered subwavelength structure on GaAs using spin-coated Ag ink mask.

    PubMed

    Yeo, Chan Il; Kwon, Ji Hye; Jang, Sung Jun; Lee, Yong Tak

    2012-08-13

    We present a simple, cost-effective, large scale fabrication technique for antireflective disordered subwavelength structures (d-SWSs) on GaAs substrate by Ag etch masks formed using spin-coated Ag ink and subsequent inductively coupled plasma (ICP) etching process. The antireflection characteristics of GaAs d-SWSs rely on their geometric profiles, which were controlled by adjusting the distribution of Ag etch masks via changing the concentration of Ag atoms and the sintering temperature of Ag ink as well as the ICP etching conditions. The fabricated GaAs d-SWSs drastically reduced the reflection loss compared to that of bulk GaAs (>30%) in the wavelength range of 300-870 nm. The most desirable GaAs d-SWSs for practical solar cell applications exhibited a solar-weighted reflectance (SWR) of 2.12%, which is much lower than that of bulk GaAs (38.6%), and its incident angle-dependent SWR was also investigated.

  2. 17.1%-Efficient Multi-Scale-Textured Black Silicon Solar Cells without Dielectric Antireflection Coating

    SciTech Connect

    Toor, F.; Page, M. R.; Branz, H. M.; Yuan, H. C.

    2011-01-01

    In this work we present 17.1%-efficient p-type single crystal Si solar cells with a multi-scale-textured surface and no dielectric antireflection coating. Multi-scale texturing is achieved by a gold-nanoparticle-assisted nanoporous etch after conventional micron scale KOH-based pyramid texturing (pyramid black etching). By incorporating geometric enhancement of antireflection, this multi-scale texturing reduces the nanoporosity depth required to make silicon `black' compared to nanoporous planar surfaces. As a result, it improves short-wavelength spectral response (blue response), previously one of the major limiting factors in `black-Si' solar cells. With multi-scale texturing, the spectrum-weighted average reflectance from 350- to 1000-nm wavelength is below 2% with a 100-nm deep nanoporous layer. In comparison, roughly 250-nm deep nanopores are needed to achieve similar reflectance on planar surface. Here, we characterize surface morphology, reflectivity and solar cell performance of the multi-scale textured solar cells.

  3. Titanium dioxide antireflection coating for silicon solar cells by spray deposition

    NASA Technical Reports Server (NTRS)

    Kern, W.; Tracy, E.

    1980-01-01

    A high-speed production process is described for depositing a single-layer, quarter-wavelength thick antireflection coating of titanium dioxide on metal-patterned single-crystal silicon solar cells for terrestrial applications. Controlled atomization spraying of an organotitanium solution was selected as the most cost-effective method of film deposition using commercial automated equipment. The optimal composition consists of titanium isopropoxide as the titanium source, n-butyl acetate as the diluent solvent, sec-butanol as the leveling agent, and 2-ethyl-1-hexanol to render the material uniformly depositable. Application of the process to the coating of circular, large-diameter solar cells with either screen-printed silver metallization or with vacuum-evaporated Ti/Pd/Ag metallization showed increases of over 40% in the electrical conversion efficiency. Optical characteristics, corrosion resistance, and several other important properties of the spray-deposited film are reported. Experimental evidence indicates a wide tolerance in the coating thickness upon the overall efficiency of the cell. Considerations pertaining to the optimization of AR coatings in general are discussed, and a comprehensive critical survey of the literature is presented.

  4. Acid-degradable hyperbranched polymer and its application in bottom anti-reflective coatings

    NASA Astrophysics Data System (ADS)

    Mercado, Ramil-Marcelo L.; Xu, Hao; Lowes, Joyce A.; Meador, Jim D.; Guerrero, Douglas J.

    2008-11-01

    A photosensitive developer-soluble bottom anti-reflective coating (DBARC) system is described for KrF and ArF lithographic applications. The system contains an acid-degradable branched polymer that is self-crosslinked into a polymeric film after spin coating and baking at high temperature, rendering a solvent-insoluble coating. The DBARC coating is tunable in terms having the appropriate light absorption (k value) and thickness for desirable reflection control. After the exposure of the resist, the DBARC layer decrosslinks into developer-soluble small molecules in the presence of photoacid generator (PAG). Thus the DBARC layer is removed simultaneously with the photoresist in the development process, instead of being etched away in a plasma-etching chamber in the case of traditional BARC layers. The etch budget is significantly improved so that a thin resist can be used for better resolution. Alternatively, the etch step can be omitted in the case of the formation of layers that may be damaged by exposure to plasma.

  5. Broadband and wide-angle hybrid antireflection coatings prepared by combining interference multilayers with subwavelength structures

    NASA Astrophysics Data System (ADS)

    Bruynooghe, Stéphane; Schulze, Marcel; Helgert, Michael; Challier, Michel; Tonova, Diana; Sundermann, Michael; Koch, Thomas; Gatto, Alexandre; Kley, Ernst-Bernhard

    2016-07-01

    To reduce the intensity of the Fresnel reflections of optical components, subwavelength structures prepared by reactive ion etching of SiO2 thin films were combined as the outermost layer with a multilayer system made of conventional thin-film materials. A hybrid coating was thus realized, with the nanoscaled structured outermost layer expected to further improve the antireflection properties of common interference stacks. The microscopic and optical spectroscopic analysis of the subwavelength structures revealed that pillar-shaped nanostructures formed during etching exhibit low-refractive-index properties and have a depth-dependent refractive index. To take into account the refractive-index gradient in the coating design, the optical properties of the nanostructures were modeled using the effective-medium approximation. The calculated average effective refractive index turned out to be 1.11 at 500-nm wavelength. A hybrid coating was designed to minimize the residual reflectance in the 400-nm to 900-nm spectral range for BK7 glass substrate. Experimental results demonstrated that the hybrid-coating approach yields a low residual reflectance with very good omnidirectional properties, owing to the properties of the nanostructured surface.

  6. Highly transparent triboelectric nanogenerator for harvesting water-related energy reinforced by antireflection coating.

    PubMed

    Liang, Qijie; Yan, Xiaoqin; Gu, Yousong; Zhang, Kui; Liang, Mengyuan; Lu, Shengnan; Zheng, Xin; Zhang, Yue

    2015-03-13

    Water-related energy is an inexhaustible and renewable energy resource in our environment, which has huge amount of energy and is not largely dictated by daytime and sunlight. The transparent characteristic plays a key role in practical applications for some devices designed for harvesting water-related energy. In this paper, a highly transparent triboelectric nanogenerator (T-TENG) was designed to harvest the electrostatic energy from flowing water. The instantaneous output power density of the T-TENG is 11.56 mW/m(2). Moreover, with the PTFE film acting as an antireflection coating, the maximum transmittance of the fabricated T-TENG is 87.4%, which is larger than that of individual glass substrate. The T-TENG can be integrated with silicon-based solar cell, building glass and car glass, which demonstrates its potential applications for harvesting waste water energy in our living environment and on smart home system and smart car system.

  7. Characterization and simulation on antireflective coating of amorphous silicon oxide thin films with gradient refractive index

    NASA Astrophysics Data System (ADS)

    Huang, Lu; Jin, Qi; Qu, Xingling; Jin, Jing; Jiang, Chaochao; Yang, Weiguang; Wang, Linjun; Shi, Weimin

    2016-08-01

    The optical reflective properties of silicon oxide (SixOy) thin films with gradient refractive index are studied both theoretically and experimentally. The thin films are widely used in photovoltaic as antireflective coatings (ARCs). An effective finite difference time domain (FDTD) model is built to find the optimized reflection spectra corresponding to structure of SixOy ARCs with gradient refractive index. Based on the simulation analysis, it shows the variation of reflection spectra with gradient refractive index distribution. The gradient refractive index of SixOy ARCs can be obtained in adjustment of SiH4 to N2O ratio by plasma-enhanced chemical vapor deposition (PECVD) system. The optimized reflection spectra measured by UV-visible spectroscopy confirms to agree well with that simulated by FDTD method.

  8. Preparation of a Functionally Graded Fluoropolymer Thin Film and Its Application to Antireflective Coating

    NASA Astrophysics Data System (ADS)

    Senda, Kazuo; Matsuda, Tsuyoshi; Kawanishi, Takumi; Tanaka, Kuniaki; Usui, Hiroaki

    2013-05-01

    Fluoropolymer thin films were prepared by the ion-assisted vapor deposition polymerization (IAD) of 2-(perfluorohexyl) ethylacrylate (Rf-6) under Ar ion irradiation. The ion acceleration voltage Va largely affected the film characteristics. With increasing Va, the adhesion strength between the film and the substrate improved, while the surface energy and the refractive index increased. To attain a high adhesion strength, a low surface energy, and a low optical reflectivity simultaneously, a functionally graded film was prepared by varying Va from 300 to 0 V continually in the course of film growth. As a consequence, an antireflective coating with good adhesion and low surface energy was obtained. The optical reflectivity of a glass substrate was reduced from 4.9 to 0.55% at a wavelength of 400 nm by depositing a 100-nm-thick single-layer functionally graded fluoropolymer film. The surface energy of this film was 8.5 mJ/m2.

  9. New generation of bottom anti-reflective coatings (BARCs): photodefinable BARCs

    NASA Astrophysics Data System (ADS)

    Guerrero, Douglas J.; Trudgeon, Tonya

    2003-06-01

    Three polymer systems, polycarbonates, polysulfonyl esters, and hybrid carbonate-sulfones, were evaluated as materials for a new generation of bottom anti-reflective coatings (BARCs). The polymers were tested for their solubility in accepted industry solvents, resistance to photoresist solvents after casting, thermal stability, and photosensitivity. From these, polysulfonyl esters show more promising properties as photodefinable BARCs than the other systems because of their good solvent solubility and resistance to photoresist solvents after casting. These polymers can be formulated in ethyl lactate (EL) or 1-methoxy-2-acetoxypropane (PGMEA) but are insoluble in the same solvents after curing above 170°C. The polysulfonyl esters were thermally stable up to ~300°C in air. The cured films were exposed with DUV light at 200 to 600 mJ/cm2. After exposure, the films can be easily removed in alkaline developer.

  10. Single-material multilayer ZnS as anti-reflective coating for solar cell applications

    NASA Astrophysics Data System (ADS)

    Salih, Ammar T.; Najim, Aus A.; Muhi, Malek A. H.; Gbashi, Kadhim R.

    2017-04-01

    Multilayer Zinc Sulfide (ZnS) is a promising low cost antireflective coating for solar cell applications, in this work; thin films with novel structure containing cubic and hexagonal phases were successfully deposited by thermal evaporation technique with three different layers. XRD analysis confirms the existence of both phases and high specific surface area. AFM analysis reveals that films with three layers have lower roughness and average grain size than other films. The optical measurements obtained by UV-vis, the calculated values of refractive index and reflectivity using some well known refractive index-band gap relations indicate that thin films with triple layer TL-ZnS have lower refractive index and reflectivity than other films, empirical equations were suggested and show the quantum confinement effects on band gap and reflectivity.

  11. Highly transparent triboelectric nanogenerator for harvesting water-related energy reinforced by antireflection coating

    NASA Astrophysics Data System (ADS)

    Liang, Qijie; Yan, Xiaoqin; Gu, Yousong; Zhang, Kui; Liang, Mengyuan; Lu, Shengnan; Zheng, Xin; Zhang, Yue

    2015-03-01

    Water-related energy is an inexhaustible and renewable energy resource in our environment, which has huge amount of energy and is not largely dictated by daytime and sunlight. The transparent characteristic plays a key role in practical applications for some devices designed for harvesting water-related energy. In this paper, a highly transparent triboelectric nanogenerator (T-TENG) was designed to harvest the electrostatic energy from flowing water. The instantaneous output power density of the T-TENG is 11.56 mW/m2. Moreover, with the PTFE film acting as an antireflection coating, the maximum transmittance of the fabricated T-TENG is 87.4%, which is larger than that of individual glass substrate. The T-TENG can be integrated with silicon-based solar cell, building glass and car glass, which demonstrates its potential applications for harvesting waste water energy in our living environment and on smart home system and smart car system.

  12. A Low-loss Metasurface Antireflection Coating on Dispersive Surface Plasmon Structure

    NASA Astrophysics Data System (ADS)

    Jeon, Jiyeon; Bhattarai, Khagendra; Kim, Deok-Kee; Kim, Jun Oh; Urbas, Augustine; Lee, Sang Jun; Ku, Zahyun; Zhou, Jiangfeng

    2016-11-01

    Over the years, there has been increasing interest in the integration of metal hole array (MHA) with optoelectronic devices, as a result of enhanced coupling of incident light into the active layer of devices via surface plasmon polariton (SPP) resonances. However, not all incident light contributes to the SPP resonances due to significant reflection loss at the interface between incident medium and MHA. Conventional thin-film antireflection (AR) coating typically does not work well due to non-existing material satisfying the AR condition with strong dispersion of MHA’s effective impedances. We demonstrate a single-layer metasurface AR coating that completely eliminates the refection and significantly increases the transmission at the SPP resonances. Operating at off-resonance wavelengths, the metasurface exhibits extremely low loss and does not show resonant coupling with the MHA layer. The SPP resonance wavelengths of MHA layer are unaffected whereas the surface wave is significantly increased, thereby paving the way for improved performance of optoelectronic devices. With an improved retrieval method, the metasurface is proved to exhibit a high effective permittivity () and extremely low loss (tan δ ~ 0.005). A classical thin-film AR coating mechanism is identified through analytical derivations and numerical simulations.

  13. Optical breathing of nano-porous antireflective coatings through adsorption and desorption of water

    NASA Astrophysics Data System (ADS)

    Nielsen, Karsten H.; Kittel, Thomas; Wondraczek, Katrin; Wondraczek, Lothar

    2014-10-01

    We report on the direct consequences of reversible water adsorption on the optical performance of silica-based nanoporous antireflective (AR) coatings as they are applied on glass in photovoltaic and solar thermal energy conversion systems. In situ UV-VIS transmission spectroscopy and path length measurements through high-resolution interferometric microscopy were conducted on model films during exposure to different levels of humidity and temperature. We show that water adsorption in the pores of the film results in a notable increase of the effective refractive index of the coating. As a consequence, the AR effect is strongly reduced. The temperature regime in which the major part of the water can be driven-out rapidly lies in the range of 55°C and 135°C. Such thermal desorption was found to increase the overall transmission of a coated glass by ~ 1%-point. As the activation energy of isothermal desorption, we find a value of about 18 kJ/mol. Within the experimental range of our data, the sorption and desorption process is fully reversible, resulting in optical breathing of the film. Nanoporous AR films with closed pore structure or high hydrophobicity may be of advantage for maintaining AR performance under air exposure.

  14. A Low-loss Metasurface Antireflection Coating on Dispersive Surface Plasmon Structure

    PubMed Central

    Jeon, Jiyeon; Bhattarai, Khagendra; Kim, Deok-Kee; Kim, Jun Oh; Urbas, Augustine; Lee, Sang Jun; Ku, Zahyun; Zhou, Jiangfeng

    2016-01-01

    Over the years, there has been increasing interest in the integration of metal hole array (MHA) with optoelectronic devices, as a result of enhanced coupling of incident light into the active layer of devices via surface plasmon polariton (SPP) resonances. However, not all incident light contributes to the SPP resonances due to significant reflection loss at the interface between incident medium and MHA. Conventional thin-film antireflection (AR) coating typically does not work well due to non-existing material satisfying the AR condition with strong dispersion of MHA’s effective impedances. We demonstrate a single-layer metasurface AR coating that completely eliminates the refection and significantly increases the transmission at the SPP resonances. Operating at off-resonance wavelengths, the metasurface exhibits extremely low loss and does not show resonant coupling with the MHA layer. The SPP resonance wavelengths of MHA layer are unaffected whereas the surface wave is significantly increased, thereby paving the way for improved performance of optoelectronic devices. With an improved retrieval method, the metasurface is proved to exhibit a high effective permittivity () and extremely low loss (tan δ ~ 0.005). A classical thin-film AR coating mechanism is identified through analytical derivations and numerical simulations. PMID:27805052

  15. Comparisons between laser damage and optical electric field behaviors for hafnia/silica antireflection coatings.

    PubMed

    Bellum, John; Kletecka, Damon; Rambo, Patrick; Smith, Ian; Schwarz, Jens; Atherton, Briggs

    2011-03-20

    We compare designs and laser-induced damage thresholds (LIDTs) of hafnia/silica antireflection (AR) coatings for 1054 nm or dual 527 nm/1054 nm wavelengths and 0° to 45° angles of incidence (AOIs). For a 527 nm/1054 nm, 0° AOI AR coating, LIDTs from three runs arbitrarily selected over three years are ∼20 J/cm2 or higher at 1054 nm and <10 J/cm2 at 527 nm. Calculated optical electric field intensities within the coating show two intensity peaks for 527 nm but not for 1054 nm, correlating with the lower (higher) LIDTs at 527 nm (1054 nm). For 1054 nm AR coatings at 45° and 32° AOIs and S and P polarizations (Spol and Ppol), LIDTs are high for Spol (>35 J/cm2) but not as high for Ppol (>30 J/cm2 at 32° AOI; ∼15 J/cm2 at 45° AOI). Field intensities show that Ppol discontinuities at media interfaces correlate with the lower Ppol LIDTs at these AOIs. For Side 1 and Side 2 dual 527 nm/1054 nm AR coatings of a diagnostic beam splitter at 22.5° AOI, Spol and Ppol LIDTs (>10 J/cm2 at 527 nm; >35 J/cm2 at 1054 nm) are consistent with Spol and Ppol intensity behaviors.

  16. Responsivity enhancement of mid-infrared PbSe detectors using CaF2 nano-structured antireflective coatings

    NASA Astrophysics Data System (ADS)

    Weng, Binbin; Qiu, Jijun; Yuan, Zijian; Larson, Preston R.; Strout, Gregory W.; Shi, Zhisheng

    2014-01-01

    The CaF2 nano-structures grown by thermal vapor deposition are presented. Significant responsivity improvement (>200%) of mid-infrared PbSe detectors incorporating a 200 nm nano-structured CaF2 coating was observed. The detector provides a detectivity of 4.2 × 1010 cm . Hz1/2/W at 3.8 μm, which outperforms all the reported un-cooled PbSe detectors. Structural investigations show that the coating is constructed by tapered-shape nanostructures, which creates a gradient refractive-index profile. Analogy to moth-eye antireflective mechanism, the gradient refractive-index nanostructures play the major roles for this antireflection effect. Some other possible mechanisms that help enhance the device performance are also discussed in the work.

  17. Antireflection coating on metallic substrates for solar energy and display applications

    NASA Astrophysics Data System (ADS)

    Hsiao, Wei-Yuan; Tang, Chien-Jen; Lee, Kun-Hsien; Jaing, Cheng-Chung; Kuo, Chien-Cheng; Chen, Hsi-Chao; Chang, Hsing-Hua; Lee, Cheng-Chung

    2010-08-01

    Normally metallic films are required for solar energy and display related coatings. To increase the absorbing efficiency or contrast, it is necessary to apply an antireflection coating (ARC) on the metal substrate. However, the design of a metal substrate is very different from the design of a dielectric substrate, since the optical constant of metallic thin film is very dependent on its thickness and microstructure. In this study, we design and fabricate ARCs on Al substrates using SiO2 and Nb2O5 as the dielectric materials and Nb for the metal films. The ARC successfully deposited on the Al substrate had the following structure: air/SiO2/Nb2O5/Metal/Nb2O5/Al. The measured average reflectance of the ARC is less than 1% in the visible region. We found that it is better to use a highly refractive material than a low refractive material. The thickness of the metallic film can be thicker with the result that it is easier to control and has a lesser total thickness. The total thickness of the ARC is less than 200 nm. We successfully fabricated a solar absorber and OLED device with the ARC structure were successfully fabricated.

  18. Process development and impurities analysis for the bottom antireflective coating material

    NASA Astrophysics Data System (ADS)

    Ko, Fu-Hsiang; Chen, Hsuen-Li; Huang, Tiao-Yuan; Cheng, Hsu-Chun; Ko, Chu-Jung; Chu, Tieh-Chi

    2001-08-01

    The optical behavior of semiconductor bottom antireflective coating (BARC) material was investigated by both the measurement and simulation methods. The effects of spin- coating rate, interface reflection, BARC layer thickness and photoresist layer thickness were studied. Our results indicated that the 62.5 nm of BARC layer had strong effect on suppressing the light reflection of wavelength of 248 nm form the wafer surface, irrespective of the photoresist layer thickness. Based on the gravimetric method, a high throughput and one-step microwave digestion procedure was developed for the BARC materials. The digestion efficiency increased with the digestion duration and the temperature. By following the established one-step microwave digestion method and inductively coupled plasma mass spectrometry determination, the detection limits obtained for Cr, Ni, Cu, An and Pb were in 0.1 to 1.11 ppb levels. The spike recoveries of the metallic impurities were in the range 86- 102% for the BARC materials. The analytical results of the BARC samples were found to be in reasonably good agreement with our previous method, and the analytical throughput can achieve up to 20 samples per hour for the analysis of 5 elements.

  19. Investigation on the Ability of Antireflection Coating to Withstand the Destructive Effects of Laser Radiation in IR Range (10.6 Micrometers),

    DTIC Science & Technology

    2014-09-26

    at the mid-IR, KCl and NaCl are commonly selected as substrates. But for the CO2 laser , a Ge substrate coated with a *i ZnS AR coating, is still widely...FOREIGN TECHNOLOGY DIVISION INVESTIGATION ON THE ABILITY OF ANTIREFLECTION COATING TO WITHSTAND THE DESTRUCTIVE EFFECTS OF LASER RADIATION IN IR RANGE...INVESTIGATION ON THE ABILITY OF ANTIREFLECTION COATING TO WITHSTAND THE DESTRUCTIVE EFFECTS OF LASER RADIATION IN IR RANGE (10.6 pm) By: Wang Jingrui, Liu Jien

  20. The POLARBEAR Cosmic Microwave Background Polarization Experiment and Anti-Reflection Coatings for Millimeter Wave Observations

    NASA Astrophysics Data System (ADS)

    Quealy, Erin Elizabeth

    polarized reflections off of the refractive optics inside the receiver. Specifically, the antenna-coupled detector scheme relies on a high dielectric lenslet for each pixel on the focal plane. A large portion of this thesis discusses development of anti-reflection (AR) coatings for the high curvature lenslet surface. The AR coating technologies discussed are also applicable to other optical elements, such as reimaging lenses and half-wave plates. A single layer coating is used on the pbone lenslet array, and a two layer coating is presented for use in pbtwo. The two layer coating method can be extended to wider bandwidth AR coatings.

  1. Impact of different cleaning processes on the laser damage threshold of antireflection coatings for Z-Backlighter optics at Sandia National Laboratories

    DOE PAGES

    Field, Ella; Bellum, John; Kletecka, Damon

    2014-11-06

    We have examined how different cleaning processes affect the laser-induced damage threshold of antireflection coatings for large dimension, Z-Backlighter laser optics at Sandia National Laboratories. Laser damage thresholds were measured after the coatings were created, and again 4 months later to determine which cleaning processes were most effective. There is a nearly twofold increase in laser-induced damage threshold between the antireflection coatings that were cleaned and those that were not cleaned. Aging of the coatings after 4 months resulted in even higher laser-induced damage thresholds. Also, the laser-induced damage threshold results revealed that every antireflection coating had a high defectmore » density, despite the cleaning process used, which indicates that improvements to either the cleaning or deposition processes should provide even higher laser-induced damage thresholds.« less

  2. Impact of different cleaning processes on the laser damage threshold of antireflection coatings for Z-Backlighter optics at Sandia National Laboratories

    SciTech Connect

    Field, Ella; Bellum, John; Kletecka, Damon

    2014-11-06

    We have examined how different cleaning processes affect the laser-induced damage threshold of antireflection coatings for large dimension, Z-Backlighter laser optics at Sandia National Laboratories. Laser damage thresholds were measured after the coatings were created, and again 4 months later to determine which cleaning processes were most effective. There is a nearly twofold increase in laser-induced damage threshold between the antireflection coatings that were cleaned and those that were not cleaned. Aging of the coatings after 4 months resulted in even higher laser-induced damage thresholds. Also, the laser-induced damage threshold results revealed that every antireflection coating had a high defect density, despite the cleaning process used, which indicates that improvements to either the cleaning or deposition processes should provide even higher laser-induced damage thresholds.

  3. Reactive gas pulsing sputtering process, a promising technique to elaborate silicon oxynitride multilayer nanometric antireflective coatings

    NASA Astrophysics Data System (ADS)

    Farhaoui, A.; Bousquet, A.; Smaali, R.; Moreau, A.; Centeno, E.; Cellier, J.; Bernard, C.; Rapegno, R.; Réveret, F.; Tomasella, E.

    2017-01-01

    The oxynitride materials present a high versatility, which enables their properties to be controlled by tuning their elemental composition. This is the case for silicon oxynitrides used for multilayer antireflective coatings (ARCs), where several thin films with various refractive indexes are needed. Different techniques allow for the modification of the thin film composition. In this paper, we investigate the reactive gas pulsing sputtering process to easily tune the thin film composition, from an oxide to a nitride, by controlling the averaged oxygen flow rate, without reducing the deposition rate, compared to a conventional reactive process (CP). We then demonstrated that the refractive indexes of films deposited by this pulsing process (PP) can be varied in the same range compared to films obtained by CP (from 1.83 to 1.45 at 1.95 eV), whereas their extinction coefficients remain low. Finally, the multilayer ARC has been simulated and optimized by a genetic algorithm for wavelength at 600 nm and for the silicon substrate. Various optimized multilayer (mono-, bi- and tri-layers) structures have been deposited by the PP technique and characterized. They are presented in good agreement with the simulated reflectivity. Hence, the PP allows for an easy depositing tri-layer system with a reasonable deposition rate and low reflectivity (8.1% averaged on 400-750 nm visible light range).

  4. Highly transparent triboelectric nanogenerator for harvesting water-related energy reinforced by antireflection coating

    PubMed Central

    Liang, Qijie; Yan, Xiaoqin; Gu, Yousong; Zhang, Kui; Liang, Mengyuan; Lu, Shengnan; Zheng, Xin; Zhang, Yue

    2015-01-01

    Water-related energy is an inexhaustible and renewable energy resource in our environment, which has huge amount of energy and is not largely dictated by daytime and sunlight. The transparent characteristic plays a key role in practical applications for some devices designed for harvesting water-related energy. In this paper, a highly transparent triboelectric nanogenerator (T-TENG) was designed to harvest the electrostatic energy from flowing water. The instantaneous output power density of the T-TENG is 11.56 mW/m2. Moreover, with the PTFE film acting as an antireflection coating, the maximum transmittance of the fabricated T-TENG is 87.4%, which is larger than that of individual glass substrate. The T-TENG can be integrated with silicon-based solar cell, building glass and car glass, which demonstrates its potential applications for harvesting waste water energy in our living environment and on smart home system and smart car system. PMID:25765205

  5. Optimization of the antireflection coating of thin epitaxial crystalline silicon solar cells

    DOE PAGES

    Selj, Josefine K.; Young, David; Grover, Sachit

    2015-08-28

    In this study we use an effective weighting function to include the internal quantum efficiency (IQE) and the effective thickness, Te, of the active cell layer in the optical modeling of the antireflection coating (ARC) of very thin crystalline silicon solar cells. The spectrum transmitted through the ARC is hence optimized for efficient use in the given cell structure and the solar cell performance can be improved. For a 2-μm thick crystalline silicon heterojunction solar cell the optimal thickness of the Indium Tin Oxide (ITO) ARC is reduced by ~8 nm when IQE data and effective thickness are taken intomore » account compared to the standard ARC optimization, using the AM1.5 spectrum only. The reduced ARC thickness will shift the reflectance minima towards shorter wavelengths and hence better match the absorption of very thin cells, where the short wavelength range of the spectrum is relatively more important than the long, weakly absorbed wavelengths. For this cell, we find that the optimal thickness of the ITO starts at 63 nm for very thin (1 μm) active Si layer and then increase with increasing Te until it saturates at 71 nm for Te > 30 μm.« less

  6. Efficient Colorful Perovskite Solar Cells Using a Top Polymer Electrode Simultaneously as Spectrally Selective Antireflection Coating.

    PubMed

    Jiang, Youyu; Luo, Bangwu; Jiang, Fangyuan; Jiang, Fuben; Fuentes-Hernandez, Canek; Liu, Tiefeng; Mao, Lin; Xiong, Sixing; Li, Zaifang; Wang, Tao; Kippelen, Bernard; Zhou, Yinhua

    2016-12-14

    Organometal halide perovskites have shown excellent optoelectronic properties and have been used to demonstrate a variety of semiconductor devices. Colorful solar cells are desirable for photovoltaic integration in buildings and other aesthetically appealing applications. However, the realization of colorful perovskite solar cells is challenging because of their broad and large absorption coefficient that commonly leads to cells with dark-brown colors. Herein, for the first time, we report a simple and efficient strategy to achieve colorful perovskite solar cells by using the transparent conducting polymer (poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS) as a top electrode and simultaneously as an spectrally selective antireflection coating. Vivid colors across the visible spectrum are attained by engineering optical interference effects among the transparent PEDOT:PSS polymer electrode, the hole-transporting layer and the perovskite layer. The colored perovskite solar cells display power conversion efficiency values from 12.8 to 15.1% (from red to blue) when illuminated from the FTO glass side and from 11.6 to 13.8% (from red to blue) when illuminated from the PEDOT:PSS side. The new approach provides an advanced solution for fabricating colorful perovskite solar cells with easy processing and high efficiency.

  7. Optimization of the antireflection coating of thin epitaxial crystalline silicon solar cells

    SciTech Connect

    Selj, Josefine K.; Young, David; Grover, Sachit

    2015-08-28

    In this study we use an effective weighting function to include the internal quantum efficiency (IQE) and the effective thickness, Te, of the active cell layer in the optical modeling of the antireflection coating (ARC) of very thin crystalline silicon solar cells. The spectrum transmitted through the ARC is hence optimized for efficient use in the given cell structure and the solar cell performance can be improved. For a 2-μm thick crystalline silicon heterojunction solar cell the optimal thickness of the Indium Tin Oxide (ITO) ARC is reduced by ~8 nm when IQE data and effective thickness are taken into account compared to the standard ARC optimization, using the AM1.5 spectrum only. The reduced ARC thickness will shift the reflectance minima towards shorter wavelengths and hence better match the absorption of very thin cells, where the short wavelength range of the spectrum is relatively more important than the long, weakly absorbed wavelengths. For this cell, we find that the optimal thickness of the ITO starts at 63 nm for very thin (1 μm) active Si layer and then increase with increasing Te until it saturates at 71 nm for Te > 30 μm.

  8. Antireflection TiO x Coating with Plasmonic Metal Nanoparticles for Silicon Solar Cells.

    PubMed

    Starowicz, Z; Lipiński, M; Berent, K; Socha, R; Szczepanowicz, K; Kruk, T

    2013-03-01

    It is known that the light scattering from the metal particles deposited on the surfaces of cells can be used for increasing light trapping in the solar cells. In this work, plasmonic structures are composite materials that consisted of silver nanoparticles embedded in dielectric films of TiO x -used as cell antireflection coating. The films are deposited by sol-gel method using spin-on technique. Microstructure of prepared samples is analyzed by SEM observation. Good homogenity and particles density was obtained by this simple, cheap, and short time-demanding method. We demonstrate that due to light scattering by metal particles, the plasmonic-ARC layer is more effective than TiO x layer without Ag nanoparticles. Implementation of nanoparticles on bare cell surface was carried out too. The influence of the plasmonic structures on the silicon solar cells parameters is presented as well. We announce about 5 % additional growth in short circuit current for cells with nanoparticles.

  9. Localized dielectric breakdown and antireflection coating in metal-oxide-semiconductor photoelectrodes

    NASA Astrophysics Data System (ADS)

    Ji, Li; Hsu, Hsien-Yi; Li, Xiaohan; Huang, Kai; Zhang, Ye; Lee, Jack C.; Bard, Allen J.; Yu, Edward T.

    2017-01-01

    Silicon-based photoelectrodes for solar fuel production have attracted great interest over the past decade, with the major challenge being silicon's vulnerability to corrosion. A metal-insulator-semiconductor architecture, in which an insulator film serves as a protection layer, can prevent corrosion but must also allow low-resistance carrier transport, generally leading to a trade-off between stability and efficiency. In this work, we propose and demonstrate a general method to decouple the two roles of the insulator by employing localized dielectric breakdown. This approach allows the insulator to be thick, which enhances stability, while enabling low-resistance carrier transport as required for efficiency. This method can be applied to various oxides, such as SiO2 and Al2O3. In addition, it is suitable for silicon, III-V compounds, and other optical absorbers for both photocathodes and photoanodes. Finally, the thick metal-oxide layer can serve as a thin-film antireflection coating, which increases light absorption efficiency.

  10. Anthracene-organosiloxane spin-on antireflective coating for KrF lithography

    NASA Astrophysics Data System (ADS)

    Kennedy, Joseph T.; Baldwin-Hendricks, Teri; Hebert, Mello; Suedmeyer, Arlene

    2003-06-01

    A sacrificial, spin-on 248nm UV absorbing organosiloxane film has been developed to enable via first trench last (VFTL) dual-damascene patterning. Amongst other design objectives one key material requirement was that the film be SiO based to facilitate trench etch. Because our starting organosiloxane polymer is transparent a chromophores that absorbs at 248 nm had to be included. Anthracene was selected as it offered the largest amount of absorption per mole. Unfortunately, commercially available anthracene moieties with different functional groups when added directly to the organosiloxane polymer solution resulted in films of very marginal quality. The primary issue was the poor solubility and thermal stability of the anthracene compound within the organosiloxane matrix. To address this fundamental problem the chromophore was stabilized by chemically attaching it to ethyl-orthosilicate. The resulting molecule, 9-anthracene carboxy-methyl triethoxysilane (TESAC) was developed. By combining the appropriate amounts of TESAC, TEOS and other organo-TEOS monomers with the appropriate solvents and a catalyst a stable, 248nm light absorbing anthracene-organosiloxane polymer was developed. This work has led to the development of Duo248 organosiloxane based bottom antireflective coatings. Topics such as the development of TESAC, lithography, plasma etch and selective removal will be discussed.

  11. Wafer-scale broadband antireflective silicon fabricated by metal-assisted chemical etching using spin-coating Ag ink.

    PubMed

    Yeo, Chan Il; Song, Young Min; Jang, Sung Jun; Lee, Yong Tak

    2011-09-12

    We report broadband antireflective disordered subwavelength structures (d-SWSs), which were fabricated on 4-inch silicon wafers by spin-coating Ag ink and metal-assisted chemical etching. The antireflection properties of the d-SWSs depend on its dimensions and heights, which were changed by the sintering temperature of the spin-coated Ag ink and etching time. The fabricated d-SWSs drastically reduced surface reflection over a wide range of wavelengths and incident angles, providing good surface uniformity. The d-SWSs with the most appropriate geometry for practical solar cell applications exhibit only 1.23% solar-weighted reflectance in the wavelength range of 300-1100 nm and average reflectance <5% up to an incident angle of 55° in the wavelength range of 300-2500 nm. This simple and low-cost nanofabrication method for antireflection could be of great importance in optical device applications because it allows mass production without any lithography processes or sophisticated equipment.

  12. Zinc-embedded silica nanoparticle layer in a multilayer coating on a glass substrate achieves broadband antireflection and high transparency

    NASA Astrophysics Data System (ADS)

    Kim, Sang Woo; Bae, Dong-Sik; Shin, Hyunho

    2004-12-01

    A zinc-embedded silica (Zn-SiO2) nanoparticle layer has been applied as the outermost layer over the three-layer coating system, Zn-SiO2/SiO2/ITO (indium tin oxide), coated on a soda-lime glass substrate. The additional coating of the zinc-embedded nanoparticle layer over the 2-layer/glass, i.e., SiO2/ITO /glass system, yielded a significant diminution in reflectance, as well as an improved transmittance as compared to the 2-layer/glass system. Plausible mechanisms responsible for such phenomena are discussed. The application of the zinc-embedded silica nanoparticle layer to the multilayer coating system is shown to provide a flexible way to achieve a broadband antireflection and a high transmission.

  13. Studies and testing of antireflective (AR) coatings for soda-lime glass

    NASA Technical Reports Server (NTRS)

    Pastirik, E. M.; Sparks, T. G.; Coleman, M. G.

    1978-01-01

    Processes for producing antireflection films on glass are concentrated in three areas: acid etching of glass, plasma etching of glass, and acid development of sodium silicate films on glass. The best transmission was achieved through the acid etching technique, while the most durable films were produced from development of sodium silicate films. Control of the acid etching technique is presently inadequate for production implementation. While films having excellent antireflective properties were fabricated by plasma etching techniques, all were water soluble.

  14. Reflective and antireflective coatings for the optical chain of the ASTRI SST-2M prototype

    NASA Astrophysics Data System (ADS)

    Bonnoli, Giacomo; Canestrari, Rodolfo; Catalano, Osvaldo; Pareschi, Giovanni; Perri, Luca; Stringhetti, Luca

    2013-09-01

    ASTRI is a Flagship Project of the Italian Ministry of Education, University and Research, led by the Italian National Institute of Astrophysics, INAF. One of the main aims of the ASTRI Project is the design, construction and on-field verification of a dual mirror (2M) end-to-end prototype for the Small Size Telescope (SST) envisaged to become part of the Cherenkov Telescope Array. The ASTRI SST-2M prototype is designed according to the Schwarzschild-Couder optical scheme, and adopts a camera based on Silicon Photo Multipliers (SiPM); it will be assembled at the INAF astronomical site of Serra La Nave on mount Etna (Catania, Italy) in the second half of 2014, and will start scientific validation phase soon after. With its 4m wide primary dish, the telescope will be sensitive to multi-TeV Very High Energy (VHE) gamma rays up to 100 TeV and above, with a point spread function of ~2 arcminutes and a wide (semiaperture 4.8°) corrected field of view. The peculiarities of the optical design and of the SiPM bandpass pushed towards specifically optimized choices in terms of reflective coatings for both the primary and the secondary mirror. Fully dielectric multi-layer coatings have been developed and tested as an option for the primary mirror, aiming to filter out the large Night Sky Background contamination at wavelengths λ>~700 nm. On the other hand, for the large monolithic secondary mirror a simpler design with quartz-overcoated aluminium has been optimized for incidences far from normality. The conformation of the ASTRI camera in turn pushed towards the design of a reimaging system based on thin pyramidal light guides, that could be optionally integrated in the focal surface, aiming to increase the fill factor. An anti-reflective coating optimized for a wide range of incident angles faraway from normality was specifically developed to enhance the UV-optical transparency of these elements. The issues, strategy, simulations and experimental results are thoroughly

  15. Single-material zinc sulfide bi-layer antireflection coatings for GaAs solar cells.

    PubMed

    Leem, Jung Woo; Jun, Dong-Hwan; Heo, Jonggon; Park, Won-Kyu; Park, Jin-Hong; Cho, Woo Jin; Kim, Do Eok; Yu, Jae Su

    2013-09-09

    We demonstrated the efficiency improvement of GaAs single-junction (SJ) solar cells with the single-material zinc sulfide (ZnS) bi-layer based on the porous/dense film structure, which was fabricated by the glancing angle deposition (GLAD) method, as an antireflection (AR) coating layer. The porous ZnS film with a low refractive index was formed at a high incident vapor flux angle of 80° in the GLAD. Each optimum thickness of ZnS bi-layer was determined by achieving the lowest solar weighted reflectance (SWR) using a rigorous coupled-wave analysis method in the wavelength region of 350-900 nm, extracting the thicknesses of 20 and 50 nm for dense and porous films, respectively. The ZnS bi-layer with a low SWR of ~5.8% considerably increased the short circuit current density (J(sc)) of the GaAs SJ solar cell to 25.57 mA/cm(2), which leads to a larger conversion efficiency (η) of 20.61% compared to the conventional one without AR layer (i.e., SWR~31%, J(sc) = 18.81 mA/cm(2), and η = 14.82%). Furthermore, after the encapsulation, its J(sc) and η values were slightly increased to 25.67 mA/cm(2) and 20.71%, respectively. For the fabricated solar cells, angle-dependent reflectance properties and external quantum efficiency were also studied.

  16. The design of broad band anti-reflection coatings for solar cell applications

    NASA Astrophysics Data System (ADS)

    Siva Rama Krishna, Angirekula; Sabat, Samrat Lagnajeet; Ghanashyam Krishna, Mamidipudi

    2017-01-01

    The design of broadband anti-reflection coatings (ARCs) for solar cell applications using multiobjective differential evolutionary (MODE) algorithms is reported. The effect of thickness and refractive index contrast within the layers of the ARC on the bandwidth of reflectance is investigated in detail. In the case of the hybrid plasmonic ARC structures the effect of size, shape and filling fraction of silver (Ag) nanoparticles on the reflectance is studied. Bandwidth is defined as the spectral region of wavelengths over which the reflectance is below 2%. Single, two and three layers ARCs (consisting of MgF2, Al2O3, Si3N4, TiO2 and ZnS or combinations of these materials) were simulated for performance evaluation on an a-Si photovoltaic cell. It is observed that the three layer ARC consisting of MgF2/Si3N4/TiO2(ZnTe) of 81/42/36 nm thicknesses, respectively, exhibited a weighted reflectance of 1.9% with a bandwidth of 450 nm over the wavelength range of 300-900 nm. The ARC bandwidth could be further improved by embedding randomly distributed Ag nanoparticles of size between 100 and 120 nm on a two layer ARC consisting of Al2O3/TiO2 with thickness of 42 nm and 56 nm respectively. This plasmon-dielectric hybrid ARC design exhibited a weighted reflectance of 0.6% with a bandwidth of 560 nm over the wavelength range of 300-900 nm.

  17. The effects of the bottom anti-reflective coating with different baked temperatures and thicknesses on nanoscale patterns

    NASA Astrophysics Data System (ADS)

    Zheng, Jie; Li, Ling; Chen, Weidong

    2015-12-01

    The bottom anti-reflective coating (BARC) material can enhance the resolution of the nanopatterns structures in laser interference lithography process. In this study, WIDE-B ARC material was investigated to confirm the reduction of the vertical standing wave which leads to defect of nanopatterns. And the critical dimension (CD) of 100 nm L/S patterns with and without the application of BARC material was fabricated by laser interference lithography technology. The compared results showed that BARC can effectively reduce CD swing and obtain more uniform nanopatterns. Meanwhile, we also verified the influence of cured temperature and film thickness of BARC on the uniformity of nanopatterns.

  18. Antireflection-coated blue GaN laser diodes in an external cavity and Doppler-free indium absorption spectroscopy.

    PubMed

    Hildebrandt, Lars; Knispel, Richard; Stry, Sandra; Sacher, Joachim R; Schael, Frank

    2003-04-20

    Commercially available GaN-based laser diodes were antireflection coated in our laboratory and operated in an external cavity in a Littrow configuration. A total tuning range of typically 4 nm and an optical output power of up to 30 mW were observed after optimization of the external cavity. The linewidth was measured with a beterodyne technique, and 0.8 MHz at a sweep time of 50 ms was obtained. The mode-hop-free tuning range was more than 50 GHz. We demonstrated the performance of the laser by detecting the saturated absorption spectrum of atomic indium at 410 nm, allowing observation of well-resolved Lamb dips.

  19. Single mode operation and extended scanning of anti-reflection coated visible laser diodes in a Littrow cavity

    NASA Astrophysics Data System (ADS)

    Lonsdale, D. J.; Andrews, D. A.; King, T. A.

    2004-05-01

    A method to increase the mode-hop-free tuning range is presented that is suitable for application with visible and short wavelength laser diodes, and relaxes the requirement on high tolerance mechanical components. Depending on the diode and cavity, the theory predicts an improvement of up to eight times the FSR of the extended cavity. In our system, an anti-reflection coated AlGaInP laser diode showed a mode-hop-free scan of 8 GHz, which is characteristic for the wavelength used in the device. Greater scanning ranges are predicted for shorter wavelength sources.

  20. All-oxide broadband antireflection coatings by plasma ion assisted deposition: design, simulation, manufacturing and re-optimization.

    PubMed

    Wilbrandt, Steffen; Stenzel, Olaf; Kaiser, Norbert

    2010-09-13

    A new all-oxide design for broadband antireflection coatings with significantly reduced impact of deposition errors to the final reflectance is presented. Computational manufacturing including re-optimization during deposition has been used in the design work to account for maximum insensibility of the design with respect to deposition errors typical for plasma ion assisted deposition PIAD. Repeated deposition runs with the deducted monitoring and re-optimization strategy verify the validity of the simulations and the stability of the derived design solution.

  1. Wide band antireflective coatings Al2O3 / HfO2 / MgF2 for UV region

    NASA Astrophysics Data System (ADS)

    Winkowski, P.; Marszałek, Konstanty W.

    2013-07-01

    Deposition technology of the three layers antireflective coatings consists of hafnium compound are presented in this paper. Oxide films were deposited by means of e-gun evaporation in vacuum of 5x10-5 mbar in presence of oxygen and fluoride films by thermal evaporation. Substrate temperature was 250°C. Coatings were deposited onto optical lenses made from quartz glass (Corning HPFS). Thickness and deposition rate were controlled by thickness measuring system Inficon XTC/2. Simulations leading to optimization of thickness and experimental results of optical measurements carried during and after deposition process were presented. Physical thickness measurements were made during deposition process and were equal to 43 nm/74 nm/51 nm for Al2O3 / HfO2 / MgF2 respectively. Optimization was carried out for ultraviolet region from 230nm to the beginning of visible region 400 nm. In this region the average reflectance of the antireflective coating was less than 0.5% in the whole range of application.

  2. A simplified method for generating periodic nanostructures by interference lithography without the use of an anti-reflection coating

    SciTech Connect

    Kapon, Omree; Muallem, Merav; Palatnik, Alex; Aviv, Hagit; Tischler, Yaakov R.

    2015-11-16

    Interference lithography has proven to be a useful technique for generating periodic sub-diffraction limited nanostructures. Interference lithography can be implemented by exposing a photoresist polymer to laser light using a two-beam arrangement or more simply a one beam configuration based on a Lloyd's Mirror Interferometer. For typical photoresist layers, an anti-reflection coating must be deposited on the substrate to prevent adverse reflections from cancelling the holographic pattern of the interfering beams. For silicon substrates, such coatings are typically multilayered and complex in composition. By thinning the photoresist layer to a thickness well below the quarter wavelength of the exposing beam, we demonstrate that interference gratings can be generated without an anti-reflection coating on the substrate. We used ammonium dichromate doped polyvinyl alcohol as the positive photoresist because it provides excellent pinhole free layers down to thicknesses of 40 nm, and can be cross-linked by a low-cost single mode 457 nm laser, and can be etched in water. Gratings with a period of 320 nm and depth of 4 nm were realized, as well as a variety of morphologies depending on the photoresist thickness. This simplified interference lithography technique promises to be useful for generating periodic nanostructures with high fidelity and minimal substrate treatments.

  3. A simplified method for generating periodic nanostructures by interference lithography without the use of an anti-reflection coating

    NASA Astrophysics Data System (ADS)

    Kapon, Omree; Muallem, Merav; Palatnik, Alex; Aviv, Hagit; Tischler, Yaakov. R.

    2015-11-01

    Interference lithography has proven to be a useful technique for generating periodic sub-diffraction limited nanostructures. Interference lithography can be implemented by exposing a photoresist polymer to laser light using a two-beam arrangement or more simply a one beam configuration based on a Lloyd's Mirror Interferometer. For typical photoresist layers, an anti-reflection coating must be deposited on the substrate to prevent adverse reflections from cancelling the holographic pattern of the interfering beams. For silicon substrates, such coatings are typically multilayered and complex in composition. By thinning the photoresist layer to a thickness well below the quarter wavelength of the exposing beam, we demonstrate that interference gratings can be generated without an anti-reflection coating on the substrate. We used ammonium dichromate doped polyvinyl alcohol as the positive photoresist because it provides excellent pinhole free layers down to thicknesses of 40 nm, and can be cross-linked by a low-cost single mode 457 nm laser, and can be etched in water. Gratings with a period of 320 nm and depth of 4 nm were realized, as well as a variety of morphologies depending on the photoresist thickness. This simplified interference lithography technique promises to be useful for generating periodic nanostructures with high fidelity and minimal substrate treatments.

  4. Enhanced broadband and omni-directional performance of polycrystalline Si solar cells by using discrete multilayer antireflection coatings.

    PubMed

    Oh, Seung Jae; Chhajed, Sameer; Poxson, David J; Cho, Jaehee; Schubert, E Fred; Tark, Sung Ju; Kim, Donghwan; Kim, Jong Kyu

    2013-01-14

    The performance enhancement of polycrystalline Si solar cells by using an optimized discrete multilayer anti-reflection (AR) coating with broadband and omni-directional characteristics is presented. Discrete multilayer AR coatings are optimized by a genetic algorithm, and experimentally demonstrated by refractive-index tunable SiO₂ nano-helix arrays and co-sputtered (SiO₂)x(TiO₂)₁₋x thin film layers. The optimized multilayer AR coating shows a reduced total reflection, leading to the high incident-photon-to-electron conversion efficiency over a correspondingly wide range of wavelengths and incident angles, offering a very promising way to harvest more solar energy by virtually any type of solar cells for a longer time of a day.

  5. Effect of antireflection coating on the crystallization of amorphous silicon films by flash lamp annealing

    NASA Astrophysics Data System (ADS)

    Sonoda, Yuki; Ohdaira, Keisuke

    2017-04-01

    We succeed in decreasing the fluence of a flash-lamp pulse required for the crystallization of electron-beam (EB)-evaporated amorphous silicon (a-Si) films using silicon nitride (SiN x ) antireflection films. The antireflection effect of SiN x is confirmed not only when SiN x is placed on the surface of a-Si or flash lamp annealing (FLA) is performed from the film side, but also when SiN x is inserted between glass and a-Si and a flash pulse is supplied from the glass side. We also quantitatively confirm, by calculating flash-lamp pulse energies actually reaching a-Si films using reflectance spectra, that the reduction in the fluence of a flash-lamp pulse for the crystallization of a-Si films is due to the antireflection effect of SiN x .

  6. Broadband moth-eye antireflection coatings fabricated by low-cost nanoimprinting

    NASA Astrophysics Data System (ADS)

    Chen, Q.; Hubbard, G.; Shields, P. A.; Liu, C.; Allsopp, D. W. E.; Wang, W. N.; Abbott, S.

    2009-06-01

    Subwavelength scale antireflection moth-eye structures in silicon were fabricated by a wafer-scale nanoimprint technique and demonstrated an average reflection of 1% in the spectral range from 400 to 1000 nm at normal incidence. An excellent antireflection property out to large incident angles is shown with the average reflection below 8% at 60°. Pyramid array gave an almost constant average reflection of about 10% for an incident angle up to 45° and concave-wall column array produced an approximately linear relation between the average reflection and the incident angles. The technique is promising for improving conversion efficiencies of silicon solar cells.

  7. Layer-by-layer fabrication of broad-band superhydrophobic antireflection coatings in near-infrared region.

    PubMed

    Zhang, Lianbin; Li, Yang; Sun, Junqi; Shen, Jiacong

    2008-03-01

    Broad-band superhydrophobic antireflective (AR) coatings in near infrared (NIR) region were readily fabricated on silicon or quartz substrates by a layer-by-layer (LbL) assembly technique. First, a porous poly(diallyldimethylammonium chloride) (PDDA)/SiO2 nanoparticle multilayer coating with AR property was prepared by LbL deposition of PDDA and 200 nm SiO2 nanoparticles. PDDA was then alternately assembled with sodium silicate on the PDDA/SiO2 nanoparticle coating to prepare a two-level hierarchical surface. Superhydrophobic AR coating with a water contact angle of 154 degrees was finally obtained after chemical vapor deposition of a layer of fluoroalkylsilane on the hierarchical surface. Quartz substrate with the as-fabricated superhydrophobic AR coating has a maximal transmittance above 98% of incidence light in the NIR region, which is increased by five percent compared with bare quartz substrate. Simultaneously, the superhydrophobic property endows the AR coating with water-repellent ability. Such superhydrophobic AR coatings can effectively avoid the disturbance of water vapor on their AR property and are expected to be applicable under humid environments.

  8. Synthesis of antireflective silica coatings through the synergy of polypeptide layer-by-layer assemblies and biomineralization

    NASA Astrophysics Data System (ADS)

    Lee, Yung-Lun; Lin, Ting-Xuan; Hsu, Feng-Ming; Jan, Jeng-Shiung

    2016-01-01

    We report a versatile approach to synthesize silica coatings with antireflective (AR) characteristics through the combination of a layer-by-layer (LbL) assembly technique and biomineralization. LbL assembled decanoyl-modified poly(l-lysine)/poly(l-glutamic acid) (PLL-g-Dec/PLGA) multilayer films were used as templates for silica mineralization, followed by calcination. The specific deposition of silica onto the LbL polypeptide assemblies through amine-catalyzed polycondensation resulted in silica coatings that exhibited the transcription of the nano-/microstructured polypeptide films and their film thickness and porosity can be tuned by varying the number of bilayers, degree of substitution, and PLL molecular weight. AR silica coatings exhibiting more than 6% increase in transmittance in the near UV/visible spectral range can be obtained at an optimized refractive index, thickness, and surface roughness. The abrasion test showed that the silica coatings exhibited sufficient structural durability due to continuous silica nanostructures and low surface roughness. This study demonstrated that nanostructured thin films can be synthesized for AR coatings using the synergy between the LbL assembly technique and biomineralization.We report a versatile approach to synthesize silica coatings with antireflective (AR) characteristics through the combination of a layer-by-layer (LbL) assembly technique and biomineralization. LbL assembled decanoyl-modified poly(l-lysine)/poly(l-glutamic acid) (PLL-g-Dec/PLGA) multilayer films were used as templates for silica mineralization, followed by calcination. The specific deposition of silica onto the LbL polypeptide assemblies through amine-catalyzed polycondensation resulted in silica coatings that exhibited the transcription of the nano-/microstructured polypeptide films and their film thickness and porosity can be tuned by varying the number of bilayers, degree of substitution, and PLL molecular weight. AR silica coatings exhibiting

  9. Two-layer anti-reflection coating with mullite and polyimide foam for large-diameter cryogenic infrared filters.

    PubMed

    Inoue, Yuki; Hamada, Takaho; Hasegawa, Masaya; Hazumi, Masashi; Hori, Yasuto; Suzuki, Aritoki; Tomaru, Takayuki; Matsumura, Tomotake; Sakata, Toshifumi; Minamoto, Tomoyuki; Hirai, Tohru

    2016-12-01

    We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for use at cryogenic temperatures in millimeter wave measurements. Thermally sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background polarization measurements, such as POLARBEAR-2 (PB-2).

  10. Functional photocatalytically active and scratch resistant antireflective coating based on TiO2 and SiO2

    NASA Astrophysics Data System (ADS)

    Mazur, M.; Wojcieszak, D.; Kaczmarek, D.; Domaradzki, J.; Song, S.; Gibson, D.; Placido, F.; Mazur, P.; Kalisz, M.; Poniedzialek, A.

    2016-09-01

    Antireflection (AR) multilayer coating, based on combination of five TiO2 and SiO2 thin films, was deposited by microwave assisted reactive magnetron sputtering process on microscope glass substrates. In this work X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy and wettability measurements were used to characterize the structural and surface properties of the deposited coating. These studies revealed that prepared coating was amorphous with low surface roughness. Photocatalytic properties were determined based on phenol decomposition reaction. Measurements of optical properties showed that transmittance in the visible wavelength range was increased after the deposition of AR coating as-compared to bare glass substrate. The mechanical properties were determined on the basis of nano-indentation and scratch resistance tests. Performed research has shown that deposition of an additional thin 10 nm thick TiO2 thin film top layer, the prepared AR coating was photocatalytically active, hydrophobic, scratch resistant and had increased hardness as-compared to bare glass substrate. These results indicate that prepared AR multilayer could be used also as a self-cleaning and protective coating.

  11. How reduced vacuum pumping capability in a coating chamber affects the laser damage resistance of HfO2/SiO2 antireflection and high reflection coatings.

    DOE PAGES

    Field, Ella Suzanne; Bellum, John Curtis; Kletecka, Damon E.

    2016-06-01

    Optical coatings with the highest laser damage thresholds rely on clean conditions in the vacuum chamber during the coating deposition process. A low base pressure in the coating chamber, as well as the ability of the vacuum system to maintain the required pressure during deposition, are important aspects of limiting the amount of defects in an optical coating that could induce laser damage. Our large optics coating chamber at Sandia National Laboratories normally relies on three cryo pumps to maintain low pressures for e-beam coating processes. However, on occasion, one or more of the cryo pumps have been out ofmore » commission. In light of this circumstance, we explored how deposition under compromised vacuum conditions resulting from the use of only one or two cryo pumps affects the laser-induced damage thresholds of optical coatings. Finally, the coatings of this study consist of HfO2 and SiO2 layer materials and include antireflection coatings for 527 nm at normal incidence, and high reflection coatings for 527 nm, 45⁰ angle of incidence (AOI), in P-polarization (P-pol).« less

  12. Effect of Different TiO2-SiO2 Multilayer Coatings Applied by Sol-Gel Method on Antireflective Property

    NASA Astrophysics Data System (ADS)

    lari, Najme; Ahangarani, Shahrokh; Shanaghi, Ali

    2015-07-01

    Multilayer thin films prepared using the sol-gel process have been used in many antireflection applications. In this paper, antireflective nanoscale multilayer TiO2-SiO2 coatings were formed on both sides of the glass substrates by combining sol-gel method and dip coating techniques. The coatings were carried out using tetraethyl orthosilicate as precursor for SiO2 and tetrabutyl orthotitanate as precursor for TiO2. The coatings prepared in this work were characterized using scanning electron microscope, Fourier-transformed infrared spectrophotometer and UV-Visible spectrophotometer. The SiO2 top layer coatings showed excellent antireflection in the wavelength range of 400-800 nm where the transmittance of glass substrate is significantly lower. By increasing the number of double TiO2-SiO2 layers, the transmission of the coated glasses increased due to applied multilayer coating properties. Six-layer sol-gel TiO2-SiO2 coatings showed the highest visible transmittance about 99.25% at the band of 550-650 nm.

  13. Influence of coating thickness on laser-induced damage characteristics of anti-reflection coatings irradiated by 1064  nm nanosecond laser pulses.

    PubMed

    Song, Zhi; Cheng, Xinbin; Ma, Hongping; Zhang, Jinlong; Ma, Bin; Jiao, Hongfei; Wang, Zhanshan

    2017-02-01

    The influence of coating thickness on laser-induced damage (LID) characteristics of anti-reflection (AR) coatings irradiated by 1064 nm nanosecond laser pulses was investigated. Two HfO2/SiO2 AR coatings with different physical thicknesses, 0.7 and 2.7 μm, were prepared and tested. To study the effect of coating thickness on a laser-induced damage threshold (LIDT) in isolation, electric field intensities (EFIs) at the substrate-coating interface were kept the same by using proper AR designs. Moreover, 2 nm artificial gold particles with a density of 10  mm-2 were implanted into the substrate-coating interface to achieve reliable experimental results. An optical microscope (OM) and a scanning electron microscope (SEM) were used for an online LIDT test and offline LID morphology observation, respectively. The typical LID morphology of thicker AR coatings was flat bottom craters with diameters of 20-50 μm, which can be easily observed by an online OM. For thinner AR coatings, hemispherical craters with diameters down to 1 μm were found as typical LID morphology by a SEM. However, these tiny craters could not be observed by an online OM. Moreover, such tiny craters did not grow with subsequent pulses, so they did not degrade the functional laser damage resistance of the thin AR coatings. When identified with an online OM, the LIDT of thinner AR coatings is found to be about two times higher than the thicker ones, and large delamination was mainly found as the LID morphology of AR coatings with high fluence. When observed with a SEM, the LIDT of thin AR coatings with tiny craters was over 60% lower than the LIDT of thick AR coatings, which agrees with the model that less energy is required to form smaller LID craters of thinner coatings.

  14. ZnSe hollow nanospheres in mechanically stable near-IR antireflection coatings for ZnSe substrates

    NASA Astrophysics Data System (ADS)

    Li, Chao; Luo, Rui-Chun; Mao, Yong-Qiang; Du, Xi-Wen; Yang, Jing

    2016-09-01

    Though possessing low absorption throughout a wide infrared (IR) spectral regime, owing to a high refractive index, zinc selenide substrates are generally covered by antireflection coatings (ARCs) for practical optical uses. However, achieving a high transmission of ZnSe substrates in the near-IR (NIR) region is still challenging. Herein, for the first time, colloidal ZnSe hollow nanospheres (HNSs) smaller than 100 nm were prepared and adopted to assemble ARCs for ZnSe substrates. The voiding kinetics of the HNSs was found to agree well with the nanoscale Kirkendall effect, and the self-diffusion of the Zn ion in the core was faster than its diffusion through the ZnSe shell. With single-index ARCs, the transmission of ZnSe substrates was remarkably enhanced in the NIR region, with up to an 18% increase at 840 nm. Besides, the ZnSe HNS-based ARCs showed superior mechanical stability even under violent ultrasonication in organic solutions. We expect that ZnSe HNSs will make it possible to construct graded-index ARCs to realize omnidirectional and broadband antireflection in IR, through further tuning of HNSs’ void fraction.

  15. 17.1%-Efficient Multi-Scale-Textured Black Silicon Solar Cells without Dielectric Antireflection Coating: Preprint

    SciTech Connect

    Toor, F.; Page, M. R.; Branz, H. M.; Yuan, H. C.

    2011-07-01

    In this work we present 17.1%-efficient p-type single crystal Si solar cells with a multi-scale-textured surface and no dielectric antireflection coating. Multi-scale texturing is achieved by a gold-nanoparticle-assisted nanoporous etch after conventional micron scale KOH-based pyramid texturing (pyramid black etching). By incorporating geometric enhancement of antireflection, this multi-scale texturing reduces the nanoporosity depth required to make silicon 'black' compared to nanoporous planar surfaces. As a result, it improves short-wavelength spectral response (blue response), previously one of the major limiting factors in 'black-Si' solar cells. With multi-scale texturing, the spectrum-weighted average reflectance from 350- to 1000-nm wavelength is below 2% with a 100-nm deep nanoporous layer. In comparison, roughly 250-nm deep nanopores are needed to achieve similar reflectance on planar surface. Here, we characterize surface morphology, reflectivity and solar cell performance of the multi-scale textured solar cells.

  16. Double-layer anti-reflection coating containing a nanoporous anodic aluminum oxide layer for GaAs solar cells.

    PubMed

    Yang, Tianshu; Wang, Xiaodong; Liu, Wen; Shi, Yanpeng; Yang, Fuhua

    2013-07-29

    Multilayer anti-reflection (AR) coatings can be used to improve the efficiency of Gallium Arsenide (GaAs) solar cells. We propose an alternate method to obtain optical thin films with specified refractive indices, which is using a self-assembled nanoporous anodic aluminum oxide (AAO) template as an optical thin film whose effective refractive index can be tuned by pore-widening. Different kinds of double-layer AR coatings each containing an AAO layer were designed and investigated by finite difference time domain (FDTD) method. We demonstrate that a λ /4n - λ /4n AR coating consisting of a TiO(2) layer and an AAO layer whose effective refractive index is 1.32 realizes a 96.8% light absorption efficiency of the GaAs solar cell under AM1.5 solar spectrum (400 nm-860 nm). We also have concluded some design principles of the double-layer AR coating containing an AAO layer for GaAs solar cells.

  17. Optical properties of nanostructured TiO2 thin films and their application as antireflection coatings on infrared detectors.

    PubMed

    Jayasinghe, R C; Perera, A G U; Zhu, H; Zhao, Y

    2012-10-15

    Oblique-angle deposited titanium dioxide (TiO(2)) nanorods have attracted much attention as good antireflection (AR) coating material due to their low n profile. Therefore, it is necessary to better understand the optical properties of these nanorods. TiO(2) nanorods grown on glass and Si substrates were characterized in the visible (0.4-0.8 μm) and infrared (2-12 μm) regions to extract their complex n profiles empirically. Application of these nanorods in multilayer AR coatings on infrared detectors is also discussed. Optimization of graded index profile of these AR coatings in the broad infrared region (2-12 μm) even at oblique angles of incidence is discussed. The effective coupling between the incoming light and multiple nanorod layers for reducing the reflection is obtained by optimizing the effect from Fabry-Perot oscillations. An optimized five-layer AR coating on GaN shows the reflectance less than 3.3% for normal incidence and 10.5% at 60° across the whole 2-8 μm spectral range.

  18. Understanding deviations in lithographic patterns near interfaces: Characterization of bottom anti-reflective coatings (BARC) and the BARC resist interface

    NASA Astrophysics Data System (ADS)

    Lenhart, Joseph L.; Fischer, Daniel; Sambasivan, Sharadha; Lin, Eric K.; Wu, Wen-Li; Guerrero, Douglas J.; Wang, Yubao; Puligadda, Rama

    2007-02-01

    Interactions between a bottom anti-reflective coating (BARC) and a photoresist can critically impact lithographic patterns. For example, a lithographic pattern can shrink or spread near a BARC interface, a process called undercutting or footing respectively, due to incompatibility between the two materials. Experiments were conducted on two industrial BARC coatings in an effort to determine the impact of BARC surface chemistry on the footing and undercutting phenomena. The BARC coatings were characterized by near edge X-ray absorption fine structure (NEXAFS), contact angle measurements, and neutron and X-ray reflectivity. Contact angle measurement using a variety of fluids showed that the fluid contact angles were independent of the type of BARC coating or the BARC processing temperature. NEXAFS measurements showed that the surface chemistry of each BARC was also independent of the processing temperature. These results suggest that acid-base interactions at the BARC-resist interface are not the cause of the footing-undercutting phenomena encountered in lithographic patterns.

  19. Self-organized TiO2 nanorod arrays on glass substrate for self-cleaning antireflection coatings.

    PubMed

    Mu, Qinghui; Li, Yaogang; Wang, Hongzhi; Zhang, Qinghong

    2012-01-01

    Herein we report the direct fabrication of TiO(2) subwavelength structures with 1-dimensional TiO(2) nanorods on glass substrate through solvothermal process to form self-cleaning antireflection coatings. TiO(2) precursor solutions with different solvent constituents create TiO(2) nanorods with much different morphologies grown on glass substrates. Apiculate TiO(2) nanorods with vertical orientation are grown on the glass substrate which is solvothermally treated in the precursor solution containing ethylene glycol. This glass substrate exhibit the highest transmittance of 70-85% in the range of 520-800 nm and negligible absorption in visible light region (400-800 nm). Furthermore, the TiO(2) nanorod arrays show high hydrophobicity and photocatalytic degradation ability which offer the glass substrate self-cleaning properties for both hydrophilic and oily contaminants.

  20. Nearly zero reflectance of nano-pyramids and dual-antireflection coating structure for monocrystalline silicon solar cells.

    PubMed

    Chang, Hyo Sik; Jung, Hyun-Chul

    2011-04-01

    The effect of two-step surface treatment on monocrystalline silicon solar cells was investigated. We changed the nanostructure on pyramidal surfaces by wet nano-texturing so that less light is reflected. The two-step nano-texturing process reduces the average reflectance to about 4% in the 300-1100 nm wavelength region. The use of an antireflection coating resulted in an effective reflectance of 1%. We found that the reflectance obtained by wet nano-texturing was lower than that obtained by conventional alkaline texturing. Thus, we can expect a further increase in the efficiency of silicon solar cells with two-step nano-texturing by a wet chemical process.

  1. Progress in the Growth of Yb:S-FAP Laser Crystals

    SciTech Connect

    Schaffers, K I; Tassano, J B; Waide, P A; Payne, S A; Morris, R C

    2000-07-01

    The crystal growth of Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F] is being studied for 1.047-{micro}m laser operation. These crystals are not yet routinely available and the growth of high optical quality, low loss crystals poses a challenge due to a number of crystal growth issues, including, cloudiness, bubble core defects, anomalous absorption, low-angle grain boundaries, and cracking. At this time, a growth process has been formulated to simultaneously eliminate or greatly diminish each of the defects yielding high quality material. Laser slabs of dimension 4.0 x 6.0 x 0.75 cm are being fabricated from sub-scale pieces using the diffusion bonding technique.

  2. Anti-reflection coatings on large area glass sheets. Final report, Motorola report No. 2366/4, DRD No. SE-5

    SciTech Connect

    Pastirik, E.

    1980-09-01

    Antireflective coatings which may be suitable for use on the covers of photovoltaic solar modules can be easily produced by a dipping process. The coatings are applied to glass by drawing sheets of glass vertically out of dilute aqueous sodium silicate solutions at a constant speed, allowing the adherent liquid film to dry, then exposing the dried film to concentrated sulfuric acid, followed by a water rinse and dry. The process produces coatings of good optical performance (96.7% peak transmission at 0.540 ..mu..M wavelength) combined with excellent stain and soil resistance, and good resistance to abrasion. The process is reproduceable and easily controlled.

  3. TiO2/Ni composite as antireflection coating for solar cell application

    NASA Astrophysics Data System (ADS)

    Haider, Adawiya J.; Najim, Aus A.; Muhi, Malik A. H.

    2016-07-01

    Titanium dioxide (TiO2) considered as one of the best material already used as a window in solar cells due to its antireflection capability. In this work, pure and Ni-doped (1, 3 and 5 wt%) TiO2 thin films were deposited using pulsed laser deposition (PLD) method. The optical measurements obtained by UV-vis indicate that the highest optical band gap was found with (5%) doping level (Eg=3.82 eV), corresponding to a lower reflectance and higher transmittance. Empirical equations between energy band gap and concentration level, reflectance with energy band gap, refractive index and concentration have been determined; a perfect fit with the experimental data was obtained.

  4. Enhancement of the Performance of GaAs based Solar Cells by using Plasmonic, Anti-Reflection Coating and Hydrophobic Effects

    NASA Astrophysics Data System (ADS)

    Makableh, Yahia F.

    Investigation of renewable energy resources is gaining huge momentum in recent years due to the limited fossil fuels, and their detriment impact on the environment. Solar energy is promising to meet the increased energy demand. In order to achieve this goal, solar energy has to be harvested efficiently at low cost. Therefore, higher efficiency solar cells are the primary focus of research worldwide. Photovoltaics based on InAs/GaAs intermediate band solar cells and their device performance enhancements are investigated in this dissertation. The device enhancement is carried out by surface modification methods. The dissertation work is inspired by the need of improved efficiency solar cells to meet the new energy demands. In this project, InAs/GaAs intermediate band solar cell and their device performance enhancement are investigated. The device enhancement is carried out though implementing surface modification by using plasmonic effect, anti-reflection coatings and self-cleaning surfaces. Single junction and quantum dots solar cells performance has been unsatisfying due to several optical losses especially high surface reflection. Hence, in this project, potential application of plasmonic effect and significant device performance enhancement implementing anti-reflection coating are studied experimentally. Significantly, GaAs based photovoltaics solar cells efficiencies were improved by 40 - 50 %. In addition, self-cleaning surfaces with contact angle above 156° has been achieved. This self-cleaning surface can ensure proper functionality of the anti-reflection coatings.

  5. Broadband and crack-free antireflection coatings by self-assembled moth eye patterns.

    PubMed

    Galeotti, Francesco; Trespidi, Franco; Timò, Gianluca; Pasini, Mariacecilia

    2014-04-23

    We report broadband and quasi-omnidirectional antireflective (AR) structures inspired to the nipple arrays of moth eyes. These nanocoatings, based on thin elastomeric films, are prepared by simple self-assembly processing of a co-polymer specifically designed to this purpose, and PDMS replica molding. Typically, their surface is covered by a compact distribution of hemispherical nanodomes of about 250 nm in diameter and about 100 nm in height. When these novel nanostructures are applied on a single glass surface, a maximum of 2% transmission enhancement (equivalent to a 50% reduction of the reflected component) towards wavelengths ranging from visible to near IR region is obtained. A considerable AR power is observed also at a wide range of incident angles ranging from normal to 50°. These properties could be attributed to an optimized graded refractive index profile resulting from the randomly distributed and close-packed nanodomes. Moreover, thanks to their elastomeric nature, these crack-free films can be easily applied on glass, as stickers, and periodically replaced, thus offering the possibility of easy dirt removal from an optical device.

  6. Optimal structure of light trapping in thin-film solar cells: dielectric nanoparticles or multilayer antireflection coatings?

    PubMed

    Zhao, Yongxiang; Chen, Fei; Shen, Qiang; Zhang, Lianmeng

    2014-08-10

    Recent research has found an alternative way to enhance light trapping of thin-film solar cells by using dielectric nanoparticles deposited on the cell surface. To improve the performance of light trapping, a systematic study on the influence of dielectric nanoparticles on enhancement efficiency is performed in this paper. We prove that the optimal dielectric nanoparticles are substantially equivalent to the multilayer antireflection coatings (ARCs) with a "low-high-low" dielectric constant profile. Moreover, it is demonstrated that the use of a simple two-layer SiO2/SiC ARC can reach 34.15% enhancement, which has exceeded the ideal limit of 32% of nanoparticles structure including plasmonic Ag nanoparticles, dielectric SiC, and TiO2 nanoparticles. That means the optimal multilayer ARCs structure is obviously superior to the optimal dielectric nanoparticles structure, and the deposition of a simple two-layer SiO2/SiC structure on top of a thin-film silicon solar cell can significantly enhance photoelectron generation and hence, result in superior performance of thin-film solar cells.

  7. High-Quality Hollow Closed-Pore Silica Antireflection Coatings Based on Styrene-Acrylate Emulsion @ Organic-Inorganic Silica Precursor.

    PubMed

    Guo, Zhaolong; Zhao, Haixin; Zhao, Wei; Wang, Tao; Kong, Depeng; Chen, Taojing; Zhang, Xiaoyan

    2016-05-11

    Making use of a facile and low-cost way for the preparation of a hierarchically organized novel hollow closed-pore silica antireflective coating (CHAR) with tailored optical properties and a mechanical reliability is of great interest in the field of solar photovoltaic technology. The process mainly contains two aspects: (1) a styrene-acrylate emulsion @ organic-inorganic silica precursor (SA@OISP) core/shell hierarchical nanostructure, consisting of a sacrificial styrene-acrylate (SA) primary template, was fabricated using a sol-gel method; (2) the self-assembly of the nanostructures leads to SA@OISP nanospheres forming the high-quality hollow closed-pore silica antireflection coating (CHAR) by a dip-coating process and a subsequent calcination treatment. The resulting SA@OISP nanospheres have a mean diameter of 65.2 nm and contained a SA soft core with a mean diameter of approximately 54.8 nm and an organic-inorganic silica precursor (OISP) shell with a thickness of approximately 6-10 nm. Furthermore, the prepared CHAR film exhibited a high transmittance and good ruggedness. An average transmittance (TAV) of 97.64% was obtained, and the value is close to the ideal single-layered antireflection coating (98.09%) over a broad range of wavelengths (from 380 to 1100 nm). The CHAR film showed a stable TAV, with attenuation values of less than 0.8% and 0.43% after the abrasion test and the damp heat test, respectively. The conversion efficiency of the CHAR coating cover solar modules tends to be increased by 3.75%. The promising results obtained in this study suggest that the CHAR film was considered as an essential component of the solar module and were expected to provide additional solar energy harvest under extreme outdoor climates.

  8. Broad Band Antireflection Coating on Zinc Sulphide Window for Shortwave infrared cum Night Vision System

    NASA Astrophysics Data System (ADS)

    Upadhyaya, A. S.; Bandyopadhyay, P. K.

    2012-11-01

    In state of art technology, integrated devices are widely used or their potential advantages. Common system reduces weight as well as total space covered by its various parts. In the state of art surveillance system integrated SWIR and night vision system used for more accurate identification of object. In this system a common optical window is used, which passes the radiation of both the regions, further both the spectral regions are separated in two channels. ZnS is a good choice for a common window, as it transmit both the region of interest, night vision (650 - 850 nm) as well as SWIR (0.9 - 1.7 μm). In this work a broad band anti reflection coating is developed on ZnS window to enhance the transmission. This seven layer coating is designed using flip flop design method. After getting the final design, some minor refinement is done, using simplex method. SiO2 and TiO2 coating material combination is used for this work. The coating is fabricated by physical vapour deposition process and the materials were evaporated by electron beam gun. Average transmission of both side coated substrate from 660 to 1700 nm is 95%. This coating also acts as contrast enhancement filter for night vision devices, as it reflect the region of 590 - 660 nm. Several trials have been conducted to check the coating repeatability, and it is observed that transmission variation in different trials is not very much and it is under the tolerance limit. The coating also passes environmental test for stability.

  9. Thermography and k-means clustering methods for anti-reflective coating film inspection: scratch and bubble defects

    NASA Astrophysics Data System (ADS)

    Zhou, Xunfei; Wang, Hongjin; Hsieh, Sheng-Jen (Tony)

    2016-05-01

    Anti-reflective coating is widely used on telescopes, eyeglasses and screens to effectively enhance the transmission of light. However, the presence of defects such as bubbles or scratches lowers the usability and functionality of optical film. Optical cameras are often used for coating inspection, but their accuracy relies heavily on the illumination source, camera viewing angles and defect location. This paper describes an active thermography approach that can potentially overcome this issue. Eighteen scratch and bubble defects were located on AR film with dimensions ranging from 0.03mm to 4.4 mm. An infrared camera was used to capture thermal images of those defects over 65 seconds of heating. After the thermal images were acquired, time-domain analysis and space-domain analysis were conducted and k-means clustering methodology was used to highlight the defective area. Results suggest active thermography can be used to detect scratch defects with widths of 0.03mm to 4.40 mm and bubble defects with diameters ranging from 0.08 to 4 mm. For defects with dimensions larger than 0.4 mm, our algorithm can estimate the dimension with less than 15% bias. However, for defects with dimensions less than 0.4mm, the algorithm estimation error ranged from 68% to 900% due to camera resolution limitations. It should be noted that our algorithm can still distinguish a scratch defect with a width of less than one pixel. This study also suggests active thermography can detect scratch and bubble defects regardless of the location of the illumination source.

  10. Perfect anti-reflection from first principles.

    PubMed

    Kim, Kyoung-Ho; Park, Q-Han

    2013-01-01

    Reducing unwanted reflections through impedance matching, called anti-reflection, has long been an important challenge in optics and electrical engineering. Beyond trial and error optimization, however, a systematic way to realize anti-reflection is still absent. Here, we report the discovery of an analytic solution to this long standing problem. For electromagnetic waves, we find the graded permittivity and permeability that completely remove any given impedance mismatch. We demonstrate that perfect broadband anti-reflection is possible when a dispersive, graded refractive index medium is used for the impedance-matching layer. We also present a design rule for the ultra-thin anti-reflection coating which we confirm experimentally by showing the anti-reflection behavior of an exemplary λ/25-thick coating made of metamaterials. This work opens a new path to anti-reflection applications in optoelectronic device, transmission line and stealth technologies.

  11. Perfect anti-reflection from first principles

    PubMed Central

    Kim, Kyoung-Ho; Q-Han Park

    2013-01-01

    Reducing unwanted reflections through impedance matching, called anti-reflection, has long been an important challenge in optics and electrical engineering. Beyond trial and error optimization, however, a systematic way to realize anti-reflection is still absent. Here, we report the discovery of an analytic solution to this long standing problem. For electromagnetic waves, we find the graded permittivity and permeability that completely remove any given impedance mismatch. We demonstrate that perfect broadband anti-reflection is possible when a dispersive, graded refractive index medium is used for the impedance-matching layer. We also present a design rule for the ultra-thin anti-reflection coating which we confirm experimentally by showing the anti-reflection behavior of an exemplary λ/25-thick coating made of metamaterials. This work opens a new path to anti-reflection applications in optoelectronic device, transmission line and stealth technologies. PMID:23320143

  12. Self-cleaning antireflective coatings assembled from peculiar mesoporous silica nanoparticles.

    PubMed

    Li, Xiaoyu; Du, Xin; He, Junhui

    2010-08-17

    Novel mesoporous silica nanoparticles of peculiar shapes were synthesized, from which hierarchically porous silica coatings were fabricated on glass substrates via layer-by-layer (LbL) assembly, followed by calcination. These porous silica coatings were highly transparent and superhydrophilic. The maximum transmittance reached as high as 94%, whereas that of the glass substrate is 91%. The time for a droplet to spread lower than 5 degrees decreased to as short as 0.25 s. After the coating surface was treated with a low surface energy material, the surface became superhydrophobic (water contract angle >150 degrees) with a very low sliding angle of <1 degree. Compared with MCM-41-type mesoporous silica nanoparticles, the coatings fabricated using the novel mesoporous silica nanoparticles possess much better self-cleaning property. We used scanning (SEM) and transmission (TEM) electron microscopy to observe the morphology and structure of nanoparticles and surfaces. Transmission spectra and their change with time were characterized by UV-vis spectrophotometer. We studied the surface wettability by a contact angle/interface system. The influence of mesopores on the transmittance and wetting properties of coatings was discussed on the basis of experimental observations.

  13. Grass-like alumina with low refractive index for scalable, broadband, omnidirectional antireflection coatings on glass using atomic-layer deposition.

    PubMed

    Kauppinen, Christoffer; Isakov, Kirill; Sopanen, Markku

    2017-04-11

    We present a new type of nanoporous antireflection (AR) coating based on grass-like alumina with a graded refractive index profile. The grass-like alumina AR coating is fabricated using atomic layer deposition (ALD) of alumina and immersion in heated de-ionized water. Optical transmittance of 99.5% at 500 nm was achieved with average transmittance of 99.0% in the range of 350-800 nm, at normal incidence for double-side coated glass. Angular spectral transmittance (0°- 80°) of the double-side AR coated glass was also measured in the range of 350-800 nm, and found to have mean spectral transmittance of 94.0% at 60°, 85.0% at 70° and 53.1% at 80° angle of incidence, respectively. The grass-like alumina AR coating is suitable for mass production as with the presented technique even hundreds of optical components can be coated in parallel. Furthermore, as an ALD based technique the coating can be deposited conformally on surfaces with extreme topography, unlike many spin-coating, physical vapour deposition or glancing angle deposition based coatings used today.

  14. Composite films prepared by plasma ion-assisted deposition (IAD) for design and fabrication of antireflection coatings in visible and near-infrared spectral regions

    NASA Astrophysics Data System (ADS)

    Tsai, Rung-Ywan; Ho, Fang C.

    1994-11-01

    Ion-assisted deposition (IAD) processes configured with a well-controlled plasma source at the center base of a vacuum chamber, which accommodates two independent e-gun sources, is used to deposition TiO2MgF2 and TiO2-SiO2 composite films of selected component ratios. Films prepared by this technology are found durable, uniform, and nonabsorbing in visible and near-IR regions. Single- and multilayer antireflection coatings with refractive index from 1.38 to 2.36 at (lambda) equals 550 nm are presented. Methods of enhancement in optical performance of these coatings are studied. The advantages of AR coatings formed by TiO2-MgF2 composite films over those similar systems consisting of TiO2-SiO2 composite films in both visible and near-IR regions are also presented.

  15. Impact of different cleaning processes on the laser damage threshold of antireflection coatings for Z-Backlighter optics at Sandia National Laboratories

    NASA Astrophysics Data System (ADS)

    Field, Ella; Bellum, John; Kletecka, Damon

    2014-12-01

    We have examined how three different cleaning processes affect the laser-induced damage threshold (LIDT) of antireflection coatings for large dimension, Z-Backlighter laser optics at Sandia National Laboratories. Laser damage thresholds were measured after the coatings were created, and again 4 months later to determine which cleaning processes were most effective. Coatings that received cleaning exhibited the highest LIDTs compared to coatings that were not cleaned. In some cases, there is nearly a twofold increase in the LIDT between the cleaned and uncleaned coatings (19.4 J/cm2 compared to 39.1 J/cm2). Higher LIDTs were realized after 4 months of aging. The most effective cleaning process involved washing the coated surface with mild detergent, and then soaking the optic in a mixture of ethyl alcohol and deionized water. Also, the laser damage results indicate that the presence of nonpropagating (NP) damage sites dominates the LIDTs of almost every optic, despite the cleaning process used. NP damage sites can be attributed to defects such as nodules in the coating or surface contamination, which suggests that pursuing further improvements to the deposition or cleaning processes are worthwhile to achieve even higher LIDTs.

  16. Performance enhancement of plasmonics silicon solar cells using Al2O3/In NPs/TiO2 antireflective surface coating

    NASA Astrophysics Data System (ADS)

    Ho, Wen-Jeng; Lee, Yi-Yu; Lin, Chi-He; Yeh, Chien-Wu

    2015-11-01

    In this study, the enhancement of silicon solar cell photovoltaic performance by means of indium nanoparticles (In NPs) deposited on the TiO2 space layer and capped with an Al2O3 antireflective layer is demonstrated. The impressive performance enhancement is attributed to the plasmonic scattering of broadband light which occurs as a result of the Al2O3/In NPs/TiO2 antireflective coating (PARC) surface structure. The optical reflectance, photovoltaic current-voltage (I-V), external quantum efficiency (EQE), and photovoltaic performance as a function of the incident angles are measured and compared. The experimental results show that the reflectance decreases with increasing TiO2 thickness and that the lowest reflection point of the spectrum was red-shifted by the use of a PARC surface structure. EQE was significantly enhanced between 400 and 1050 nm wavelengths and much high EQE of 85% were observed for the cell with In NPs embedded in the 65-nm Al2O3/20 nm TiO2 layer structure. In comparison to a bare reference solar cell, an efficiency enhancement of 54.47% (from 10.96% to 16.93%) and a short-circuit current density enhancement of 52.83% (from 26.10 to 39.89 mA/cm2) were obtained for the cell with a 65-nm Al2O3/In NPs/20-nm TiO2 antireflection structure under normal incident illumination. In addition, for incident angles from 0° to 15°, the 0.78% decrease in conversion efficiency (from 16.71% to 16.58%) of the cell with the PARC surface structure was less than the 3.28% (from 13.86% to 13.49%) decrease of the cell with 65-nm Al2O3/20-nm TiO2 double layer antireflective coating (DL-ARC) due to the plasmonic scattering of broadband light.

  17. Efficiency enhancement of non-selenized Cu(In,Ga)Se2 solar cells employing scalable low-cost antireflective coating

    PubMed Central

    2014-01-01

    In this study, a non-selenized CuInGaSe2 (CIGS) solar device with textured zinc oxide (ZnO) antireflection coatings was studied. The ZnO nanostructure was fabricated by a low-temperature aqueous solution deposition method. With controlling the morphology of the solution-grown tapered ZnO nanorod coatings, the average reflectance of the CIGS solar device decreased from 8.6% to 2.1%, and the energy conversion efficiency increased from 9.1% to 11.1%. The performance improvement in the CuInGaSe2 thin-film solar cell was well explained due to the gradual increase of the refractive index between air and the top electrode of solar cell device by the insertion of the ZnO nanostructure. The results demonstrate a potential application of the ZnO nanostructure array for efficient solar device technology. PMID:25114632

  18. Efficiency enhancement of non-selenized Cu(In,Ga)Se2 solar cells employing scalable low-cost antireflective coating.

    PubMed

    Jheng, Bao-Tang; Liu, Po-Tsun; Wu, Meng-Chyi

    2014-01-01

    In this study, a non-selenized CuInGaSe2 (CIGS) solar device with textured zinc oxide (ZnO) antireflection coatings was studied. The ZnO nanostructure was fabricated by a low-temperature aqueous solution deposition method. With controlling the morphology of the solution-grown tapered ZnO nanorod coatings, the average reflectance of the CIGS solar device decreased from 8.6% to 2.1%, and the energy conversion efficiency increased from 9.1% to 11.1%. The performance improvement in the CuInGaSe2 thin-film solar cell was well explained due to the gradual increase of the refractive index between air and the top electrode of solar cell device by the insertion of the ZnO nanostructure. The results demonstrate a potential application of the ZnO nanostructure array for efficient solar device technology.

  19. The impact of different cleaning processes on the laser damage threshold of antireflection coatings for Z-Backlighter optics at Sandia National Laboratories

    NASA Astrophysics Data System (ADS)

    Field, Ella; Bellum, John; Kletecka, Damon

    2014-09-01

    The Z-Backlighter lasers at Sandia National Laboratories are kilojoule class, pulsed systems operating with ns pulse lengths at 527 nm and ns and sub-ps pulse lengths at 1054 nm (www.z-beamlet.sandia.gov), and are linked to the most powerful and energetic x-ray source in the world, the Z-Accelerator (http://www.sandia.gov/z-machine/). An important Z-Backlighter optic is a flat, fused silica optic measuring 32.5 cm × 32.5 cm × 1 cm with an antireflection (AR) coating on both sides. It is used as a debris shield to protect other Z-Backlighter laser optics from high-velocity particles released by the experiments conducted in the Z-Accelerator. Each experiment conducted in the Z-Accelerator releases enough debris to cloud the surface of a debris shield, which means that a debris shield cannot be used for more than one experiment. Every year, the large optics coating facility [1] at Sandia provides AR coatings for approximately 50 debris shields, in addition to AR coatings for numerous other meter-class Z-Backlighter lenses and windows. As with all Z-Backlighter optical coatings, these AR coatings must have a high laser-induced damage threshold (LIDT) in order to withstand the powerful Z-Backlighter laser fluences. Achieving a good LIDT depends not only on the coating deposition processes but also on the polishing and cleaning processes used to prepare the coated and uncoated surfaces [2]. We spend a lot of time, both before and after the coatings have been deposited, manually cleaning the optics, including the debris shields, even though they are an expendable type of optic. Therefore, in this study we have tested new cleaning methods in addition to our current method to determine their impact on the LIDT of AR coatings, and conclude whether a shorter-duration or less labor-intensive cleaning process would suffice.

  20. Antireflective polyimide based films

    NASA Astrophysics Data System (ADS)

    Cao, Yuanmei

    The goal of this work was to prepare antireflective and anti-abrasion films using polyimide and organically modified silica nanoparticle thin films. A series of thin film were prepared from colorless and soluble polyimide with organically modified silica colloids via a solution casting method. The polyimide was selected for its optical properties. Three type of organically modified silica nanoparticles were prepared by grafting polysiloxane, polyfluoroester and fluoroalkyl groups onto silica nanoparticles. The molecular weight of the polysiloxane, polyfluoroester and the amount of fluorinated alkyl groups were varied. The organically modified silica colloids were characterized by TEM, DLS, FTIR, 1H NMR, solid state 13C NMR and solid state 29Si NMR. The coatings were characterized by UV-Vis transmittance spectra and SEM. The effect of modified silica loading, the molecular weight of polymer and type of solvent on AR properties were studied. An enhancement in antireflective activity was observed for 1 wt% LPDMS modified (low molecular weight) silica coatings, 3 wt% fluorosilica-10 and 3% L-MPS-PF-SILICA nanoparticles (low molecular weight polyfluoroester modified silica) in dimethylacetamide (DMAc). In comparison with cyclopentanone (CPT), DMAc favors migration of silica particles towards coating-air interface giving higher transmittance. The migration of particles to the surface and consequent increased surface roughness were observed by SEM. The present study suggested a roll to roll solution casting method to create antireflective coatings. This approach had potential to be used for a one-step large-scale manufacturing of antireflective coating. Four acrylated bismaleimide were made via two-step process. The first step involved the solution imidization to form hydroxylated bismaleimide. In the second step, hydroxylated bismaleimide was reacted with acryloyl chloride to form acrylated bismaleimide. The acrylated bismaleimide were characterized by FTIR, 1H NMR, 13C

  1. Porous SiO₂/MgF₂ broadband antireflection coatings for superstrate-type silicon-based tandem cells.

    PubMed

    Wang, Na-Fu; Kuo, Ting-Wei; Tsai, Yu-Zen; Lin, Shi-Xiong; Hung, Pin-Kun; Lin, Chiung-Lin; Houng, Mau-Phon

    2012-03-26

    The purpose of this study is to reduce the glass substrate reflectivity over a wide spectral range (400-1200 nm) without having high reflectivity in the near-infrared region. After making porous SiO₂/MgF₂ double-layer antireflection (DLAR) thin film structure, the superstrate-type silicon-based tandem cells are added. In comparison to having only silicon-based tandem solar cells, the short-circuit current density has improved by 6.82% when porous SiO₂/MgF₂ DLAR thin film is applied to silicon-based tandem solar cells. This study has demonstrated that porous SiO₂/MgF₂ DLAR thin film structure provides antireflection properties over a broad spectral range (400-1200 nm) without having high reflectivity at near-infrared wavelengths.

  2. Antireflection Coatings 1: BASICS

    SciTech Connect

    Martin, Peter M.

    2005-11-15

    Reflections off windows, eyeglass lenses, computer and television screens, and optical components can be very annoying and sometimes dangerous. Reflection of light incident on an optical window or optical component can degrade the performance of the window and the optical system associated with the window over its operating spectral range, whether it is the human eye or an optical device. Thin films can help us with this problem.

  3. How reduced vacuum pumping capability in a coating chamber affects the laser damage resistance of HfO2/SiO2 antireflection and high-reflection coatings

    NASA Astrophysics Data System (ADS)

    Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

    2017-01-01

    Optical coatings with the highest laser damage thresholds rely on clean conditions in the vacuum chamber during the coating deposition process. A low-base pressure in the coating chamber, as well as the ability of the vacuum system to maintain the required pressure during deposition, are important aspects of limiting the amount of defects in an optical coating that could induce laser damage. Our large optics coating chamber at Sandia National Laboratories normally relies on three cryo pumps to maintain low pressures for e-beam coating processes. However, on occasion, one or more of the cryo pumps have been out of commission. In light of this circumstance, we explored how deposition under compromised vacuum conditions resulting from the use of only one or two cryo pumps affects the laser-induced damage thresholds of optical coatings. The coatings of this study consist of HfO2 and SiO2 layer materials and include antireflection coatings for 527 nm at normal incidence and high-reflection coatings for 527 nm at 45-deg angle of incidence in P-polarization.

  4. How reduced vacuum pumping capability in a coating chamber affects the laser damage resistance of HfO2/SiO2 antireflection and high reflection coatings.

    SciTech Connect

    Field, Ella Suzanne; Bellum, John Curtis; Kletecka, Damon E.

    2016-06-01

    Optical coatings with the highest laser damage thresholds rely on clean conditions in the vacuum chamber during the coating deposition process. A low base pressure in the coating chamber, as well as the ability of the vacuum system to maintain the required pressure during deposition, are important aspects of limiting the amount of defects in an optical coating that could induce laser damage. Our large optics coating chamber at Sandia National Laboratories normally relies on three cryo pumps to maintain low pressures for e-beam coating processes. However, on occasion, one or more of the cryo pumps have been out of commission. In light of this circumstance, we explored how deposition under compromised vacuum conditions resulting from the use of only one or two cryo pumps affects the laser-induced damage thresholds of optical coatings. Finally, the coatings of this study consist of HfO2 and SiO2 layer materials and include antireflection coatings for 527 nm at normal incidence, and high reflection coatings for 527 nm, 45⁰ angle of incidence (AOI), in P-polarization (P-pol).

  5. Formation of a macro-porous SiO2 layer as an anti-reflective coating on glass substrates.

    PubMed

    Park, No-Kuk; Kim, Yong Sul; Kim, Min Jung; Lee, Tae Jin; Lee, Seung Hyun; Lee, Seung Hun

    2013-11-01

    A macro-porous silica layer, consisting of a silica layer with macro-sized pores, was formed as an antireflective material on glass substrates. The silica layer and macro-pores were formed by the oxidative thermal decomposition of tetra-ethylorthorsilicate (TEOS) used as the precursor and polystyrene (PS) spherical beads used as the polymer template for the macro-pores at high temperatures. The size of pores was determined by the size of PS beads in the antireflective agent solution. The size of the PS spherical beads can be controlled by changing the concentration of styrene monomer, and the porosity of the macro pore in the silica layer could be controlled by the TEOS/PS ratio. The optimal thermal treating temperature for the formation of a macro-porous silica layer was found to be 650 degrees C. The size of the spherical type macro pores formed in the silica layer on the glass substrate was 100-150 nm. UV-Vis spectrophotometry confirmed the improved antireflective properties of the glass substrate with the macro-porous silica layer.

  6. Plasmonic effect of Ag nanoparticles in a SiON antireflective coating: engineering rules and physical barrier

    NASA Astrophysics Data System (ADS)

    Lecler, S.; Bastide, S.; Tan, J.; Qu, M.; Slaoui, A.; Fix, T.

    2016-10-01

    Surface plasmon polaritons have been proposed in the architectures of several solar cells as a way to enhance light collection and thus to increase their efficiency. Here, Ag nanoparticles (NPs) are embedded in a SiON antireflective layer using an electroless technique. The plasmonic effects are modeled and observed experimentally for NPs 5 to 200 nm in size. The systematic comparison of scattering and extinction efficiencies computed as a function of the NPs and surrounding medium properties allows establishing engineering rules, validated by the experimental measurements. The fact that Ag NPs larger than 30 nm mainly contribute to light scattering and therefore to optical path enlargement (green-red light), whereas those smaller than 15 nm absorb light by light trapping (blue-green), is demonstrated and physically explained. A physical barrier making it impossible to shift the dominant resonance beyond 650 nm is pointed out.

  7. Design of a three-layer antireflection coating for high efficiency indium phosphide solar cells using a chemical oxide as first layer

    NASA Technical Reports Server (NTRS)

    Moulot, Jacques; Faur, M.; Faur, M.; Goradia, C.; Goradia, M.; Bailey, S.

    1995-01-01

    It is well known that the behavior of III-V compound based solar cells is largely controlled by their surface, since the majority of light generated carriers (63% for GaAs and 79% for InP) are created within 0.2 mu m of the surface of the illuminated cell. Consequently, the always observed high surface recombination velocity (SRV) on these cells is a serious limiting factor for their high efficiency performance, especially for those with p-n junction made by either thermal diffusion or ion implantation. A good surface passivation layer, ideally a grown oxide as opposed to a deposited one, will cause a significant reduction in the SRV without adding interface problems, thus improving the performance of III-V compound based solar cells. Another significant benefit to the overall performance of the solar cells can be achieved by a substantial reduction of their large surface optical reflection by the use of a well designed antireflection (AR) coating. In this paper, we demonstrate the effectiveness of using a chemically grown thermally and chemically stable oxide, not only for surface passivation but also as an integral part of a 3-layer AR coating for thermally diffused p+n InP solar cells. A phosphorus-rich interfacial oxide, In(PO3)3, is grown at the surface of the p+ emitter using an etchant based on HNO3, o-H3PO4 and H2O2. This oxide has the unique properties of passivating the surface as well as serving as an efficient antireflective layer yielding a measured record high AMO open-circuit voltage of 890.3 mV on a thermally diffused InP(Cd,S) solar cell. Unlike conventional single layer AR coatings such as ZnS, Sb2O3, SiO or double layer AR coatings such as ZnS/MgF2 deposited by e-beam or resistive evaporation, this oxide preserves the stoichiometry of the InP surface. We show that it is possible to design a three-layer AR coating for a thermally diffused InP solar cell using the In(PO3)3 grown oxide as the first layer and Al2O3 and MgF2 as the second and third

  8. Design of a Three-Layer Antireflection Coating for High Efficiency Indium Phosphide Solar Cells Using a Chemical Oxide as First Layer

    NASA Technical Reports Server (NTRS)

    Moulot, Jacques; Faur, Mircea; Faur, Maria; Goradia, Chandra; Goradia, Manju; Bailey, Sheila

    1995-01-01

    It is well known that the behavior of III-V compound based solar cells is largely controlled by their surface, since the majority of light generated carriers (63% for GaAs and 79% for InP) are created within 0.2 microns of the illuminated surface of the cell. Consequently, the always observed high surface recombination velocity (SRV) on these cells is a serious limiting factor for their high efficiency performance, especially for those with the p-n junction made by either thermal diffusion or ion implantation. A good surface passivation layer, ideally, a grown oxide as opposed to a deposited one, will cause a significant reduction in the SRV without adding interface problems, thus improving the performance of III-V compound based solar cells. Another significant benefit to the overall performance of the solar cells can be achieved by a substantial reduction of their large surface optical reflection by the use of a well designed antireflection (AR) coating. In this paper, we demonstrate the effectiveness of using a chemically grown, thermally and chemically stable oxide, not only for surface passivation but also as an integral part of a 3- layer AR coating for thermally diffused p(+)n InP solar cells. A phosphorus-rich interfacial oxide, In(PO3)3, is grown at the surface of the p(+) emitter using an etchant based on HNO3, o-H3PO4 and H2O2. This oxide has the unique properties of passivating the surface as well as serving as a fairly efficient antireflective layer yielding a measured record high AM0, 25 C, open-circuit voltage of 890.3 mV on a thermally diffused InP(Cd,S) solar cell. Unlike conventional single layer AR coatings such as ZnS, Sb2O3, SiO or double layer AR coatings such as ZnS/MgF2 deposited by e-beam or resistive evaporation, this oxide preserves the stoichiometry of the InP surface. We show that it is possible to design a three-layer AR coating for a thermally diffused InP solar cell using the In(PO3)3 grown oxide as the first layer and Al2O3, MgF2 or

  9. The Mercury Laser System: An Average power, gas-cooled, Yb:S-FAP based system with frequency conversion and wavefront correction

    SciTech Connect

    Bibeau, C; Bayramian, A; Armstrong, P; Ault, E; Beach, R; Benapfl, M; Campbell, R; Dawson, J; Ebbers, C; Freitas, B; Kent, R; Liao, Z; Ladran, T; Menapace, J; Molander, B; Moses, E; Oberhelman, S; Payne, S; Peterson, N; Schaffers, K; Stolz, C; Sutton, S; Tassano, J; Telford, S; Utterback, E; Randles, M

    2005-08-31

    We report on the operation of the Mercury laser with fourteen 4 x 6 cm{sup 2} Yb:S-FAP amplifier slabs pumped by eight 100 kW peak power diode arrays. The system was continuously run at 55 J and 10 Hz for several hours, (2 x 10{sup 5} cumulative shots) with over 80% of the energy in a 6 times diffraction limited spot at 1.047 um. Improved optical quality was achieved in Yb:S-FAP amplifiers with magneto-rheological finishing, a deterministic polishing method. In addition, average power frequency conversion employing YCOB was demonstrated at 50% conversion efficiency or 22.6 J at 10 Hz.

  10. Fabrication and characterization of silicon wire solar cells having ZnO nanorod antireflection coating on Al-doped ZnO seed layer

    PubMed Central

    2012-01-01

    In this study, we have fabricated and characterized the silicon [Si] wire solar cells with conformal ZnO nanorod antireflection coating [ARC] grown on a Al-doped ZnO [AZO] seed layer. Vertically aligned Si wire arrays were fabricated by electrochemical etching and, the p-n junction was prepared by spin-on dopant diffusion method. Hydrothermal growth of the ZnO nanorods was followed by AZO film deposition on high aspect ratio Si microwire arrays by atomic layer deposition [ALD]. The introduction of an ALD-deposited AZO film on Si wire arrays not only helps to create the ZnO nanorod arrays, but also has a strong impact on the reduction of surface recombination. The reflectance spectra show that ZnO nanorods were used as an efficient ARC to enhance light absorption by multiple scattering. Also, from the current-voltage results, we found that the combination of the AZO film and ZnO nanorods on Si wire solar cells leads to an increased power conversion efficiency by more than 27% compared to the cells without it. PMID:22222067

  11. Measurements and simulations of the optical gain and anti-reflection coating modal reflectivity in quantum cascade lasers with multiple active region stacks

    SciTech Connect

    Bidaux, Y.; Terazzi, R.; Bismuto, A.; Gresch, T.; Blaser, S.; Muller, A.; Faist, J.

    2015-09-07

    We report spectrally resolved gain measurements and simulations for quantum cascade lasers (QCLs) composed of multiple heterogeneous stacks designed for broadband emission in the mid-infrared. The measurement method is first demonstrated on a reference single active region QCL based on a double-phonon resonance design emitting at 7.8 μm. It is then extended to a three-stack active region based on bound-to-continuum designs with a broadband emission range from 7.5 to 10.5 μm. A tight agreement is found with simulations based on a density matrix model. The latter implements exhaustive microscopic scattering and dephasing sources with virtually no fitting parameters. The quantitative agreement is furthermore assessed by measuring gain coefficients obtained by studying the threshold current dependence with the cavity length. These results are particularly relevant to understand fundamental gain mechanisms in complex semiconductor heterostructure QCLs and to move towards efficient gain engineering. Finally, the method is extended to the measurement of the modal reflectivity of an anti-reflection coating deposited on the front facet of the broadband QCL.

  12. Defect Band Luminescence Intensity Reversal as Related to Application of Anti-Reflection Coating on mc-Si PV Cells: Preprint

    SciTech Connect

    Guthrey, H.; Johnston, S.; Yan, F.; Gorman, B.; Al-Jassim, M.

    2012-06-01

    Photoluminescence (PL) imaging is widely used to identify defective regions within mc-Si PV cells. Recent PL imaging investigations of defect band luminescence (DBL) in mc-Si have revealed a perplexing phenomenon. Namely, the reversal of the DBL intensity in various regions of mc-Si PV material upon the application of a SiNx:H anti-reflective coating (ARC). Regions with low DBL intensity before ARC application often exhibit high DBL intensity afterwards, and the converse is also true. PL imaging alone cannot explain this effect. We have used high resolution cathodoluminescence (CL) spectroscopy and electron beam induced current (EBIC) techniques to elucidate the origin of the DBL intensity reversal. Multiple sub-bandgap energy levels were identified that change in peak position and intensity upon the application of the ARC. Using this data, in addition to EBIC contrast information, we provide an explanation for the DBL intensity reversal based on the interaction of the detected energy levels with the SiNx:H ARC application. Multiple investigations have suggested that this is a global problem for mc-Si PV cells. Our results have the potential to provide mc-Si PV producers a pathway to increased efficiencies through defect mitigation strategies.

  13. Silicon nitride anti-reflection coating on the glass and transparent conductive oxide interface for thin film solar cells and modules

    NASA Astrophysics Data System (ADS)

    Iwahashi, T.; Morishima, M.; Fujibayashi, T.; Yang, R.; Lin, J.; Matsunaga, D.

    2015-10-01

    Anti-reflection coating (ARC) is well known as an important technique to enhance solar cell performance. Typical ARC has been applied on the glass surface to reduce light reflection loss at the air/glass interface. However, reflection loss occurs not only at glass surface but also at other interfaces such as glass/transparent conductive oxide (TCO) interface. The refractive index of SiNx is tunable from 1.6 to 2.7, and the range from 1.7 to 2.0 is suitable for ARC at glass/TCO interface. In this study, we examined the AR effect of silicon nitride (SiNx) deposited by plasma enhanced chemical vapor deposition at the glass/TCO interface with thin film silicon solar cell and module. Reflectivity reduction of 1.6% for glass/ZnO substrate has been obtained with optimal SiNx layer, which contribute 2.0% gain in cell efficiency. Besides, we also confirmed the relative efficiency gain of around 2% for large-sized solar module, leading to a world-record large area stabilized module conversion efficiency of 12.34%.

  14. Improvement in light harvesting of dye-sensitized solar cells with antireflective and hydrophobic textile PDMS coating by facile soft imprint lithography.

    PubMed

    Lim, Joo Ho; Ko, Yeong Hwan; Leem, Jung Woo; Yu, Jae Su

    2015-02-09

    We demonstrated the improved conversion efficiency (η) of dye-sensitized solar cells (DSSCs) using the textile-patterned polydimethylsiloxane (PDMS) antireflection layers prepared by metal-coated textile master molds by a simple soft imprint lithography. When light propagates through the textile-patterned surface of PDMS (i.e., textile PDMS) laminated on the outer glass surface deposited with fluorine-doped tin oxide (i.e., FTO/glass), both the transmitted and diffused lights into the photo-anode of DSSCs were simultaneously enhanced. Compared to the bare FTO/glass, the textile PDMS increased the total transmittance from 82.3 to 85.1% and its diffuse transmittance was significantly increased from 5.9 to 78.1% at 550 nm of wavelength. The optical property of textile PDMS was also theoretically analyzed by the finite-difference time-domain simulation. By laminating the textile PDMS onto the outer glass surface of DSSCs, the η was enhanced from 6.04 to 6.51%. Additionally, the fabricated textile PDMS exhibited a hydrophobic surface with water contact angle of ~123.15°.

  15. Fabrication and characterization of silicon wire solar cells having ZnO nanorod antireflection coating on Al-doped ZnO seed layer.

    PubMed

    Baek, Seong-Ho; Noh, Bum-Young; Park, Il-Kyu; Kim, Jae Hyun

    2012-01-05

    In this study, we have fabricated and characterized the silicon [Si] wire solar cells with conformal ZnO nanorod antireflection coating [ARC] grown on a Al-doped ZnO [AZO] seed layer. Vertically aligned Si wire arrays were fabricated by electrochemical etching and, the p-n junction was prepared by spin-on dopant diffusion method. Hydrothermal growth of the ZnO nanorods was followed by AZO film deposition on high aspect ratio Si microwire arrays by atomic layer deposition [ALD]. The introduction of an ALD-deposited AZO film on Si wire arrays not only helps to create the ZnO nanorod arrays, but also has a strong impact on the reduction of surface recombination. The reflectance spectra show that ZnO nanorods were used as an efficient ARC to enhance light absorption by multiple scattering. Also, from the current-voltage results, we found that the combination of the AZO film and ZnO nanorods on Si wire solar cells leads to an increased power conversion efficiency by more than 27% compared to the cells without it.

  16. Optical properties of the Al2O3/SiO2 and Al2O3/HfO2/SiO2 antireflective coatings

    NASA Astrophysics Data System (ADS)

    Marszałek, Konstanty; Winkowski, Paweł; Jaglarz, Janusz

    2014-01-01

    Investigations of bilayer and trilayer Al2O3/SiO2 and Al2O3/HfO2/SiO2 antireflective coatings are presented in this paper. The oxide films were deposited on a heated quartz glass by e-gun evaporation in a vacuum of 5 × 10-3 [Pa] in the presence of oxygen. Depositions were performed at three different temperatures of the substrates: 100 °C, 200 °C and 300 °C. The coatings were deposited onto optical quartz glass (Corning HPFS). The thickness and deposition rate were controlled with Inficon XTC/2 thickness measuring system. Deposition rate was equal to 0.6 nm/s for Al2O3, 0.6 nm - 0.8 nm/s for HfO2 and 0.6 nm/s for SiO2. Simulations leading to optimization of the thin film thickness and the experimental results of optical measurements, which were carried out during and after the deposition process, have been presented. The optical thickness values, obtained from the measurements performed during the deposition process were as follows: 78 nm/78 nm for Al2O3/SiO2 and 78 nm/156 nm/78 nm for Al2O3/HfO2/SiO2. The results were then checked by ellipsometric technique. Reflectance of the films depended on the substrate temperature during the deposition process. Starting from 240 nm to the beginning of visible region, the average reflectance of the trilayer system was below 1 % and for the bilayer, minima of the reflectance were equal to 1.6 %, 1.15 % and 0.8 % for deposition temperatures of 100 °C, 200 °C and 300 °C, respectively.

  17. Antifogging and antireflection coatings fabricated by integrating solid and mesoporous silica nanoparticles without any post-treatments.

    PubMed

    Xu, Ligang; He, Junhui

    2012-06-27

    Antifogging and -reflection coatings were fabricated on glass and poly(methyl methacrylate) (PMMA) substrates by integrating solid silica nanoparticles of 25 nm (S-25) and mesoporous silica nanoparticles (MSNs) of 45 nm via layer-by-layer assembly without any post-treatments. Superhydrophilicity and a maximum transmittance of 98.5% in the visible spectral range was achieved for the (PDDA/S-25)4/(PDDA/MSNs) coating deposited on slide glass. The maximum transmittance even reached as high as 99.3% in the visible spectral range by applying a coating of (PDDA/S-25)8/(PDDA/MSNs) on PMMA substrate. Scanning and transmission electron microscopy were used to observe the morphology and structure of nanoparticles and coating surfaces. Optical properties were characterized by UV-visible spectrophotometer. Surface wettability was studied by a contact angle/interface system. The influence of mesopores was also discussed on the transmission and wetting properties of coatings. The high porosity of mesoporous nanoparticles and loose stacking of solid and mesoporous nanoparticles are considered to significantly contribute to the enhancements of both light transmission and hydrophilicity.

  18. A low cost, durable anti-reflective film for solar collectors

    NASA Technical Reports Server (NTRS)

    Pastirik, E. M.; Keeling, M. C.

    1978-01-01

    The physics of reflection reduction by thin films is briefly reviewed. Current techniques for the production of anti-reflective coatings are surveyed with respect to their applicabilities to solar panel covers. Techniques for the production of suitable anti-reflection coatings based on acid-hardened sodium silicate solutions are presented along with optical data for both acid-leached and silicate coatings

  19. Ultra-thin atomic-layer deposited alumina incorporating silica sol makes ultra-durable antireflection coatings

    NASA Astrophysics Data System (ADS)

    Li, Jia; Lan, Pinjun; Xu, Hua; Zhang, Xianpeng; Yang, Ye; Tan, Ruiqin; Jylhä, Olli; Lu, Yuehui

    2012-11-01

    We propose a strategy to make soda-lime glass maintain both high transparency and long-term durability in stringent high temperature and humid environments. Experiments reveal that the double-layered coatings with 110-nm-thick SiO2 and ultra-thin 25-nm- or 50-nm-thick Al2O3 layers, prepared by sol-gel dip coating and atomic layer deposition (ALD), respectively, exhibit the improvement of 5.88-6.32% in Tave (the average transmittance from the wavelength of 400-700 nm), as compared with that of the bare glass. On the other hand, the highly accelerated temperature and humidity stress test (HAST) confirms that both samples can sustain the 180 h test without any proven transmittance degradation, while the normalized Tave of the bare glass drastically drops to 43.1% of the initial value after the 108 h HAST. It implies that the ultra-thin Al2O3 films prepared by ALD, followed by dip-coated low-index layers such as SiO2 or nanostructured layer, can achieve both higher average transmittance and better durability, which would be of significance for the applications of ALD and dip coating techniques in the fields of consumer electronics, architecture with glass facades, and photovoltaics.

  20. Multi-layer coatings

    DOEpatents

    Maghsoodi, Sina; Brophy, Brenor L.; Abrams, Ze'ev R.; Gonsalves, Peter R.

    2016-06-28

    Disclosed herein are coating materials and methods for applying a top-layer coating that is durable, abrasion resistant, highly transparent, hydrophobic, low-friction, moisture-sealing, anti-soiling, and self-cleaning to an existing conventional high temperature anti-reflective coating. The top coat imparts superior durability performance and new properties to the under-laying conventional high temperature anti-reflective coating without reducing the anti-reflectiveness of the coating. Methods and data for optimizing the relative thickness of the under-layer high temperature anti-reflective coating and the top-layer thickness for optimizing optical performance are also disclosed.

  1. Biomimetic subwavelength antireflective gratings on GaAs.

    PubMed

    Sun, Chih-Hung; Ho, Brian J; Jiang, Bin; Jiang, Peng

    2008-10-01

    We have developed a simple and scalable bottom-up approach for fabricating moth-eye antireflective coatings on GaAs substrates. Monolayer, non-close-packed silica colloidal crystals are created on crystalline GaAs wafers by a spin-coating-based single-layer reduction technique. These colloidal monolayers can be used as etching masks during a BCl(3) dry-etch process to generate subwavelength-structured antireflective gratings directly on GaAs substrates. The gratings exhibit excellent broadband antireflective properties, and the specular reflection matches with the theoretical prediction using a rigorous coupled-wave analysis model. These bioinspired antireflection coatings have important technological applications ranging from efficient solar cells to IR detectors.

  2. a-SiCxNy:H thin films for applications in solar cells as passivation and antireflective coatings

    NASA Astrophysics Data System (ADS)

    Swatowska, Barbara; Kluska, Stanisława; Lewińska, Gabriela; Golańska, Julia; Stapiński, Tomasz

    2016-12-01

    Amorphous a-SiCxNy:H thin films may be an alternative to a-Si:N:H coatings which are commonly used in silicon solar cells. This material was obtained by PECVD (13.56 MHz) method. The reaction gases used: silane, methane, nitrogen and ammonia. The structure of the layers were investigated by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). IR absorption spectra of a-SiCxNy:H layers confirmed the presence of various hydrogen bonds - it is important for passivation of Si structural defects. The ellipsometric measurements were implemented to determine the thickness of layers d, refractive index n, extinction coefficient k and energy gap Eg. The values of the energy gap of a-SiCxNy:H layers are in the range from 1.89 to 4.34 eV. The correlation between energy gap of materials and refractive index was found. Generally the introduction of N and/or C into the amorphous silicon network rapidly increases the Eg values.

  3. Comparison of Anti-Reflective Coated and Uncoated Surfaces Figured by Pitch-Polishing and Magneto-Rheological Processes

    SciTech Connect

    Chow, R; Thomas, M D; Bickel, R; Taylor, J R

    2002-11-08

    When completed, the National Ignition Facility (NIF) will provide laser energies in the Mega-joule range. Successful pulse amplification to these extremely high levels requires that all small optics, found earlier in the beamline, have stringent surface and laser fluence requirements. In addition, they must operate reliably for 30 years constituting hundreds of thousands of shots. As part of the first four beamlines, spherical and aspherical lenses were required for the beam relaying telescopes. The magneto-rheological technique allows for faster and more accurate finishing of aspheres. The spherical and aspherical lenses were final figured using both conventional-pitch polishing processes for high quality laser optics and the magneto-rheological finishing process. The purpose of this paper is to compare the surface properties between these two finishing processes. Some lenses were set aside from production for evaluation. The surface roughness in the mid-frequency range was measured and the scatter was studied. Laser damage testing at 1064 nm (3-ns pulse width) was performed on surfaces in both the uncoated and coated condition.

  4. Optimized biomimetic antireflection nanostructure for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Tao, Fei; Chen, Jiacheng; Zhou, Hang

    2012-11-01

    Minimizing surface reflection loss is critical when designing high efficiency solar cells. In recent years, biomimetic antireflection nanostructures (such as moth-eye structures), with their extraordinary broadband and omnidirectional antireflection properties, have caught much attention. Single side biomimetic antireflection (AR) coatings show good performance in suppressing broadband reflection between air and glass interface. However, reflection from the interface between absorption layer and transparent window layer still remains. In this study, we proposed a double-side gradient-index nanostructure, and examined its reflection spectrum in comparison with different biomimetic nanostructures using a finite-difference time-domain (FDTD) simulation and effective medium theory (EMT). In order to minimize surface reflection, all abrupt interfaces were replaced by gradientindex biomimetic nanostructures, including air/glass interface and absorber/glass interface. Monolayer of silica spheres serve as double-side gradient-index nanostructures, partially immersed into photoabsorbing material. Spheres with diameter smaller than incoming light wavelength show excellent antireflection properties. From simulation results, in normal incidence, average reflection rate of optimized AR coating structure was lower to around 5% compared to originally above 25% within visible spectrum region (350nm - 850nm). Details of how to apply such biomimetic nanostructures in thin film solar cells were also discussed.

  5. Nanotip Carpets as Antireflection Surfaces

    NASA Technical Reports Server (NTRS)

    Bae, Youngsam; Mobasser, Sohrab; Manohara, Harish; Lee, Choonsup

    2008-01-01

    Carpet-like random arrays of metal-coated silicon nanotips have been shown to be effective as antireflection surfaces. Now undergoing development for incorporation into Sun sensors that would provide guidance for robotic exploratory vehicles on Mars, nanotip carpets of this type could also have many uses on Earth as antireflection surfaces in instruments that handle or detect ultraviolet, visible, or infrared light. In the original Sun-sensor application, what is required is an array of 50-micron-diameter apertures on what is otherwise an opaque, minimally reflective surface, as needed to implement a miniature multiple-pinhole camera. The process for fabrication of an antireflection nanotip carpet for this application (see Figure 1) includes, and goes somewhat beyond, the process described in A New Process for Fabricating Random Silicon Nanotips (NPO-40123), NASA Tech Briefs, Vol. 28, No. 1 (November 2004), page 62. In the first step, which is not part of the previously reported process, photolithography is performed to deposit etch masks to define the 50-micron apertures on a silicon substrate. In the second step, which is part of the previously reported process, the non-masked silicon area between the apertures is subjected to reactive ion etching (RIE) under a special combination of conditions that results in the growth of fluorine-based compounds in randomly distributed formations, known in the art as "polymer RIE grass," that have dimensions of the order of microns. The polymer RIE grass formations serve as microscopic etch masks during the next step, in which deep reactive ion etching (DRIE) is performed. What remains after DRIE is the carpet of nano - tips, which are high-aspect-ratio peaks, the tips of which have radii of the order of nanometers. Next, the nanotip array is evaporatively coated with Cr/Au to enhance the absorption of light (more specifically, infrared light in the Sun-sensor application). The photoresist etch masks protecting the apertures

  6. Effectiveness of ion cleaning to improve the laser damage threshold of HfO2/SiO2 optical coatings for high reflection and antireflection at 527 nm and 1054 nm

    NASA Astrophysics Data System (ADS)

    Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

    2016-07-01

    Preventing contamination is vital to achieving high laser-induced damage thresholds in optical coatings. The importance of removing contamination from optical substrates has led to the development of many specialized cleaning processes, including the application of solvents, acids, mild detergents, and abrasives. To further enhance contamination removal, the substrate may be treated with ion cleaning just prior to depositing the optical coating. Ion cleaning is attractive thanks to the convenience of providing in-situ treatment to optical substrates, and also avoiding the hassle of managing hazardous chemicals or applying mechanical force to scrub off detergents and other cleaning agents. In this study, we compare the effectiveness of ion cleaning for increasing the laser-induced damage thresholds of high reflection (527 nm and 1054 nm) and antireflection (527 nm) coatings. Ion cleaning was performed using a radio frequency ion source with argon and oxygen. The coatings investigated were deposited with layers of HfO2 and SiO2 in an e-beam evaporation system, and are designed to withstand nanosecond pulses from a kJ-class laser.

  7. Antireflection design concepts with equivalent layers.

    PubMed

    Schallenberg, Uwe B

    2006-03-01

    Some novel concepts of designing antireflection (AR) coatings with equivalent layers are presented. As an introduction, essential papers concerning thin-film optics and AR designs are cited, and the AR problem and a previously introduced AR-hard design type are discussed. Based on the known matrix formalism, a potential AR region, an equivalent stack index, and an equivalent substrate index are defined to use the theory of stop-band suppression as a starting point for the design of broadband AR coatings. The known multicycle AR design type is identified as a typical solution to the AR problem if the presented approach is used.

  8. Antireflective nanostructured zinc oxide arrays produced by pulsed electrodeposition

    SciTech Connect

    Klochko, N. P. Klepikova, K. S.; Khrypunov, G. S.; Volkova, N. D.; Kopach, V. R.; Lyubov, V. M.; Kirichenko, M. V.; Kopach, A. V.

    2015-02-15

    Conditions for the pulsed electrochemical deposition of nanostructured zinc oxide arrays with a certain morphology, crystal structure, and optical properties from aqueous electrolytes onto substrates of transparent electrically conducting tin dioxide and on single-crystal silicon wafers with built-in homojunctions are studied in order to develop antireflection coatings for solar cells. It is shown that it is possible to obtain single-layer planar antireflection coatings or arrays of nanorods of this material, both having the form of hexagonal prisms and exhibiting the moth-eye effect.

  9. Grazing-incidence antireflection films. I. Basic theory

    NASA Astrophysics Data System (ADS)

    Hannon, J. P.; Hung, N. V.; Trammell, G. T.; Gerdau, E.; Mueller, M.; Rüffer, R.; Winkler, H.

    1985-10-01

    We discuss the possibility of a new interference technique for x-ray and γ-ray optics-the simple idea of grazing-incidence antireflection films (GIAR films)-for creating high-efficiency antireflection coatings for near-grazing-incidence reflection of hard x rays and γ rays. The motivation is the possible application to producing ``ultranarrow'' bandpass filters for synchrotron radiation with frequency widths ~=10-8-10-6 eV, giving a unique high-resolution, long-coherence-length, x-ray source for probing soft inelastic excitations and opening up new possibilities in x-ray interferometry. In this first of two papers on nonresonant GIAR films, we develop the basic theory and discuss in detail the simplest ideas for achieving antireflection films-impedance-matched quarter-wave films and damping stabilized solutions-which can both be obtained by coating a high-density mirror with a single lower-density film.

  10. BDS Thin Film UV Antireflection Laser Damage Competition

    SciTech Connect

    Stolz, C J

    2010-10-26

    UV antireflection coatings are a challenging coating for high power laser applications as exemplified by the use of uncoated Brewster's windows in laser cavities. In order to understand the current laser resistance of UV AR coatings in the industrial and university sectors, a double blind laser damage competition was performed. The coatings have a maximum reflectance of 0.5% at 355 nm at normal incidence. Damage testing will be performed using the raster scan method with a 7.5 ns pulse length on a single testing facility to facilitate direct comparisons. In addition to the laser resistance results, details of deposition processes and coating materials will also be shared.

  11. Templated biomimetic multifunctional coatings

    NASA Astrophysics Data System (ADS)

    Sun, Chih-Hung; Gonzalez, Adriel; Linn, Nicholas C.; Jiang, Peng; Jiang, Bin

    2008-02-01

    We report a bioinspired templating technique for fabricating multifunctional optical coatings that mimic both unique functionalities of antireflective moth eyes and superhydrophobic cicada wings. Subwavelength-structured fluoropolymer nipple arrays are created by a soft-lithography-like process. The utilization of fluoropolymers simultaneously enhances the antireflective performance and the hydrophobicity of the replicated films. The specular reflectivity matches the optical simulation using a thin-film multilayer model. The dependence of the size and the crystalline ordering of the replicated nipples on the resulting antireflective properties have also been investigated by experiment and modeling. These biomimetic materials may find important technological application in self-cleaning antireflection coatings.

  12. Optimization of the genetic operators and algorithm parameters for the design of a multilayer anti-reflection coating using the genetic algorithm

    NASA Astrophysics Data System (ADS)

    Patel, Sanjaykumar J.; Kheraj, Vipul

    2015-07-01

    This paper describes a systematic investigation on the use of the genetic algorithm (GA) to accomplish ultra-low reflective multilayer coating designs for optoelectronic device applications. The algorithm is implemented using LabVIEW as a programming tool. The effects of the genetic operators, such as the type of crossover and mutation, as well as algorithm parameters, such as population size and range of search space, on the convergence of design-solution were studied. Finally, the optimal design is obtained in terms of the thickness of each layer for the multilayer AR coating using optimized genetic operators and algorithm parameters. The program is successfully tested to design AR coating in NIR wavelength range to achieve average reflectivity (R) below 10-3 over the spectral bandwidth of 200 nm with different combinations of coating materials in the stack. The random-point crossover operator is found to exhibit a better convergence rate of the solution than single-point and double-point crossover. Periodically re-initializing the thickness value of a randomly selected layer from the stack effectively prevents the solution from becoming trapped in local minima and improves the convergence probability.

  13. Irradiance enhancement and increased laser damage threshold in As₂S₃ moth-eye antireflective structures.

    PubMed

    Weiblen, R Joseph; Florea, Catalin M; Busse, Lynda E; Shaw, L Brandon; Menyuk, Curtis R; Aggarwal, Ishwar D; Sanghera, Jasbinder S

    2015-10-15

    It has been experimentally observed that moth-eye antireflective microstructures at the end of As2S3 fibers have an increased laser damage threshold relative to thin-film antireflective coatings. In this work, we computationally study the irradiance enhancement in As2S3 moth-eye antireflective microstructures in order to explain the increased damage threshold. We show that the irradiance enhancement occurs mostly on the air side of the interfaces and is minimal in the As2S3 material. We give a physical explanation for this behavior.

  14. Laser Window Surface Finishing and Coating Science

    DTIC Science & Technology

    1975-07-01

    IKlf il fie. r . *ttt\\ mil nlrol’ly h\\ lllm k Itumhvr ■ LasLr windows. Surface finishing, Thin films , Antireflection coatings , 10.6...Zuccaro) During the course of our program it is our objective to prepare antireflection (AR) film coatings for candidate infrared laser window...antireflection coatings under UHV conditions and to compare; these films with (.host- prepared under ordinary vacuum conditions. a. Experimental Results

  15. Antireflective surface patterned by rolling mask lithography

    NASA Astrophysics Data System (ADS)

    Seitz, Oliver; Geddes, Joseph B.; Aryal, Mukti; Perez, Joseph; Wassei, Jonathan; McMackin, Ian; Kobrin, Boris

    2014-03-01

    A growing number of commercial products such as displays, solar panels, light emitting diodes (LEDs and OLEDs), automotive and architectural glass are driving demand for glass with high performance surfaces that offer anti-reflective, self-cleaning, and other advanced functions. State-of-the-art coatings do not meet the desired performance characteristics or cannot be applied over large areas in a cost-effective manner. "Rolling Mask Lithography" (RML™) enables highresolution lithographic nano-patterning over large-areas at low-cost and high-throughput. RML is a photolithographic process performed using ultraviolet (UV) illumination transmitted through a soft cylindrical mask as it rolls across a substrate. Subsequent transfer of photoresist patterns into the substrate is achieved using an etching process, which creates a nanostructured surface. The current generation exposure tool is capable of patterning one-meter long substrates with a width of 300 mm. High-throughput and low-cost are achieved using continuous exposure of the resist by the cylindrical photomask. Here, we report on significant improvements in the application of RML™ to fabricate anti-reflective surfaces. Briefly, an optical surface can be made antireflective by "texturing" it with a nano-scale pattern to reduce the discontinuity in the index of refraction between the air and the bulk optical material. An array of cones, similar to the structure of a moth's eye, performs this way. Substrates are patterned using RML™ and etched to produce an array of cones with an aspect ratio of 3:1, which decreases the reflectivity below 0.1%.

  16. Fluorine-containing composition for forming anti-reflection film on resist surface and pattern formation method

    DOEpatents

    Nishi, Mineo; Makishima, Hideo

    1996-01-01

    A composition for forming anti-reflection film on resist surface which comprises an aqueous solution of a water soluble fluorine compound, and a pattern formation method which comprises the steps of coating a photoresist composition on a substrate; coating the above-mentioned composition for forming anti-reflection film; exposing the coated film to form a specific pattern; and developing the photoresist, are provided. Since the composition for forming anti-reflection film can be coated on the photoresist in the form of an aqueous solution, not only the anti-reflection film can be formed easily, but also, the film can be removed easily by rinsing with water or alkali development. Therefore, by the pattern formation method according to the present invention, it is possible to form a pattern easily with a high dimensional accuracy.

  17. Antireflective submicrometer gratings on thin-film silicon solar cells for light-absorption enhancement.

    PubMed

    Song, Young Min; Yu, Jae Su; Lee, Yong Tak

    2010-02-01

    This study reports highly efficient light-absorbing structures based on submicrometer gratings (SMGs) for thin-film crystalline silicon solar cells. The integration of SMGs into the cell structure leads to superior broadband antireflection properties compared to conventional antireflection coatings. With careful design optimization, an improvement of the cell efficiency of nearly 25.1% was obtained compared to double-layer coated solar cells. Optimized SMG structures were fabricated on a silicon substrate using interference lithography and a lenslike shape transfer process. The fabricated SMG structures exhibited low reflectivity in the wavelength range of 300-1200 nm, indicating good agreement with the simulated results.

  18. Tunable Antireflection Layers for Planar Bolometer Arrays

    NASA Technical Reports Server (NTRS)

    Brown, Ari-David; Chuss, David; Woolack, Edward; Chervenak, James; Henry, Ross; Wray, James

    2007-01-01

    It remains a challenge to obtain high-efficiency coupling of far-infrared through millimeter radiation to large-format detector arrays. The conventional approach of increasing detector coupling is to use reflective backshorts. However, this approach often results in excessive systematic errors resulting from reflections off the backshort edge. An alternate approach to both increasing quantum efficiency and reducing systematics associated with stray light is to place an antireflective coating near the front surface of the array. When incorporated with a resistive layer and placed behind the detector focal plane, the AR coating can serve to prevent optical ghosting by capturing radiation transmitted through the detector. By etching a hexagonal pattern in silicon, in which the sizes of the hexes are smaller than the wavelength of incident radiation, it is possible to fabricate a material that has a controllable dielectric constant, thereby allowing for simple tunable optical device fabrication. To this end, we have fabricated and tested tunable silicon "honeycomb" AR layers and AR/resistive layer devices. These devices were fabricated entirely out of silicon in order to eliminate problems associated with differential contraction upon detector cooling.

  19. The role of random nanostructures for the omnidirectional anti-reflection properties of the glasswing butterfly

    NASA Astrophysics Data System (ADS)

    Siddique, Radwanul Hasan; Gomard, Guillaume; Hölscher, Hendrik

    2015-04-01

    The glasswing butterfly (Greta oto) has, as its name suggests, transparent wings with remarkable low haze and reflectance over the whole visible spectral range even for large view angles of 80°. This omnidirectional anti-reflection behaviour is caused by small nanopillars covering the transparent regions of its wings. In difference to other anti-reflection coatings found in nature, these pillars are irregularly arranged and feature a random height and width distribution. Here we simulate the optical properties with the effective medium theory and transfer matrix method and show that the random height distribution of pillars significantly reduces the reflection not only for normal incidence but also for high view angles.

  20. Two-layer anti-reflection strategies for implant applications

    NASA Astrophysics Data System (ADS)

    Guerrero, Douglas J.; Smith, Tamara; Kato, Masakazu; Kimura, Shigeo; Enomoto, Tomoyuki

    2006-03-01

    A two-layer bottom anti-reflective coating (BARC) concept in which a layer that develops slowly is coated on top of a bottom layer that develops more rapidly was demonstrated. Development rate control was achieved by selection of crosslinker amount and BARC curing conditions. A single-layer BARC was compared with the two-layer BARC concept. The single-layer BARC does not clear out of 200-nm deep vias. When the slower developing single-layer BARC was coated on top of the faster developing layer, the vias were cleared. Lithographic evaluation of the two-layer BARC concept shows the same resolution advantages as the single-layer system. Planarization properties of a two-layer BARC system are better than for a single-layer system, when comparing the same total nominal thicknesses.

  1. Development of new maskless manufacturing method for anti-reflection structure and application to large-area lens with curved surface

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kazuya; Takaoka, Toshimitsu; Fukui, Hidetoshi; Haruta, Yasuyuki; Yamashita, Tomoya; Kitagawa, Seiichiro

    2016-03-01

    In general, thin-film coating process is widely applied on optical lens surface as anti-reflection function. In normal production process, at first lens is manufactured by molding, then anti-reflection is added by thin-film coating. In recent years, instead of thin-film coating, sub-wavelength structures adding on surface of molding die are widely studied and development to keep anti-reflection performance. As merits, applying sub-wavelength structure, coating process becomes unnecessary and it is possible to reduce man-hour costs. In addition to cost merit, these are some technical advantages on this study. Adhesion of coating depends on material of plastic, and it is impossible to apply anti-reflection function on arbitrary surface. Sub-wavelength structure can solve both problems. Manufacturing method of anti-reflection structure can be divided into two types mainly. One method is with the resist patterning, and the other is mask-less method that does not require patterning. What we have developed is new mask-less method which is no need for resist patterning and possible to impart an anti-reflection structure to large area and curved lens surface, and can be expected to apply to various market segments. We report developed technique and characteristics of production lens.

  2. Optimal moth eye nanostructure array on transparent glass towards broadband antireflection.

    PubMed

    Ji, Seungmuk; Song, Kyungjun; Nguyen, Thanh Binh; Kim, Namsoo; Lim, Hyuneui

    2013-11-13

    Broadband antireflection (AR) is essential for improving the photocurrent generation of photovoltaic modules or the enhancement of visibility in optical devices. Beyond conventional AR coating methods, moth eye mimicking nanostructures give new directions to enhance broadband antireflection through the selection of geometrical parameters, such as height, periodic distance, shape, and arrangement. This study numerically and experimentally investigates the behavior of light on complex nanostructures designed to mimic the surface of the moth eye with mixed shapes and various arrangements. To obtain broadband AR, we rigorously study the design parameters, such as height, periodic distance, shape, and arrangement, on a transparent quartz substrate. Several kinds of nanopillar arrays are elaborately fabricated including mixed nanostructures comprising pointy and round shapes in ordered and random arrangements via colloidal lithography. The optimal morphology of moth eye nanostructure arrays for broadband antireflection is suggested in view of reflectance and average weight transmittance.

  3. Thermal radiative properties: Coatings.

    NASA Technical Reports Server (NTRS)

    Touloukian, Y. S.; Dewitt, D. P.; Hernicz, R. S.

    1972-01-01

    This volume consists, for the most part, of a presentation of numerical data compiled over the years in a most comprehensive manner on coatings for all applications, in particular, thermal control. After a moderately detailed discussion of the theoretical nature of the thermal radiative properties of coatings, together with an overview of predictive procedures and recognized experimental techniques, extensive numerical data on the thermal radiative properties of pigmented, contact, and conversion coatings are presented. These data cover metallic and nonmetallic pigmented coatings, enamels, metallic and nonmetallic contact coatings, antireflection coatings, resin coatings, metallic black coatings, and anodized and oxidized conversion coatings.

  4. Development of broadband antireflection of high-index substrate using SiNx/SiO2

    NASA Astrophysics Data System (ADS)

    Lim, Kim Peng; Ng, Doris K. T.; Wang, Qian

    2016-03-01

    Broadband antireflection coatings are commonly required in many silicon or III-V compound semiconductor based optoelectronic devices such as solar cells, photodetectors, and image sensors so as to enhance light conversion efficiency. Conventional approach using a single-layer antireflection coating is simple and commonly used in industry but it has a limited working bandwidth. To achieve broadband or even omni-directional characteristics, structures using thick graded refractive index (GRIN) multilayers or nanostructured surfaces which have equivalent graded refractive index profile have been proposed and demonstrated. In this paper, we will show our development of broadband antireflection for high index substrate using SiNx/SiO2 via inductively coupled plasma chemical vapour deposition (ICPCVD). Global optimization of thin-film broadband antireflection coating using adaptive simulated annealing is presented. Unlike the conventional optical coating design which uses the refractive index of available materials, the optimization approach used here decides the optimal values of the refractive index as well as the thickness of each layer. The first thin-film material optimization is carried out on the ICP-CVD machine operating at low temperature of 250°C by tuning the SiH4/N2 gas ratio. The demonstrated double layer antireflection thin film reduces the average reflectance of Si surface from ~32% to ~3.17% at normal incidence for wavelength range from 400 to 1100 nm. This optical thin-film design and material development can be extended to optical wavelength filters and integrated micro-GRIN devices.

  5. One-step Maskless Fabrication and Optical Characterization of Silicon Surfaces with Antireflective Properties and a White Color Appearance

    PubMed Central

    Schneider, Ling; Feidenhans’l, Nikolaj A.; Telecka, Agnieszka; Taboryski, Rafael J.

    2016-01-01

    We report a simple one-step maskless fabrication of inverted pyramids on silicon wafers by reactive ion etching. The fabricated surface structures exhibit excellent anti-reflective properties: The total reflectance of the nano inverted pyramids fabricated by our method can be as low as 12% without any anti-reflective layers, and down to only 0.33% with a silicon nitride coating. The results from angle resolved scattering measurements indicate that the existence of triple reflections is responsible for the reduced reflectance. The surfaces with the nano inverted pyramids also exhibit a distinct milky white color. PMID:27725703

  6. One-step Maskless Fabrication and Optical Characterization of Silicon Surfaces with Antireflective Properties and a White Color Appearance

    NASA Astrophysics Data System (ADS)

    Schneider, Ling; Feidenhans'L, Nikolaj A.; Telecka, Agnieszka; Taboryski, Rafael J.

    2016-10-01

    We report a simple one-step maskless fabrication of inverted pyramids on silicon wafers by reactive ion etching. The fabricated surface structures exhibit excellent anti-reflective properties: The total reflectance of the nano inverted pyramids fabricated by our method can be as low as 12% without any anti-reflective layers, and down to only 0.33% with a silicon nitride coating. The results from angle resolved scattering measurements indicate that the existence of triple reflections is responsible for the reduced reflectance. The surfaces with the nano inverted pyramids also exhibit a distinct milky white color.

  7. Optimization of hardmask for dual anti-reflection layers

    NASA Astrophysics Data System (ADS)

    Kim, Ju-Hyun; Kim, Jeahee; Kim, Keeho

    2007-03-01

    The continuous shrinkage of critical dimensions has driven ArF lithography to resolve very small features and ever thinner resist films to prevent pattern collapse. Also importance of hardmask technology is becoming increasingly evident as the demand for both the critical dimension control and sufficient thickness of etch mask. We have developed a silicon based hardmask prepared by plasma-enhanced chemical vapor deposition (PECVD) to match organic anti-reflective coating (ARC). The ordinary single dielectric ARC or organic ARC is very sensitivity to the substrate topology. Dual ARC (dielectric ARC + organic ARC) perform a less CD variation than single ARC. In addition, this material can serve as an effective hardmask etch barrier during the plasma etch. The most advantage of Dual ARC is that we have good critical dimension uniformity (CDU) regardless of substrate thickness variation.

  8. Experimental and simulation studies of anti-reflection sub-micron conical structures on a GaAs substrate.

    PubMed

    Lee, Yeeu-Chang; Chang, Che-Chun; Chou, Yen-Yu

    2013-01-14

    In order to reduce surface reflection, anti-reflective (AR) coatings are widely used on the surfaces of solar cells to improve the efficiency of photoelectric conversion. This study employed colloidal lithography with a dry etching process to fabricate sub-micron anti-reflection structures on a GaAs substrate. Etching parameters, such as RF power and etching gas were investigated to determine their influence on surface morphology. We fabricated an array of conical structures 550 nm in diameter and 450 nm in height. The average reflectance of a bare GaAs wafer was reduced from 35.0% to 2.3% across a spectral range of 300 nm - 1200 nm. The anti-reflective performance of SWSs was also calculated using Rigorous Coupled Wave Analysis (RCWA) method. Both simulation and experiment results demonstrate a high degree of similarity.

  9. Improved antireflection properties of moth eye mimicking nanopillars on transparent glass: flat antireflection and color tuning.

    PubMed

    Ji, Seungmuk; Park, Joonsik; Lim, Hyuneui

    2012-08-07

    The sub-wavelength structures in moth eyes exhibit fascinating antireflective properties over the broadband wavelength region and at large incident angle by generating an air-mixed heterogeneous optical interface. In this work, antireflective behavior of transparent glass is observed with the elaborate controls of the nanopillar morphology. The reflectance spectrum shows a red shift and a notable light scattering with increase of the height of the nanopillars. The nanopillar arrays with a pointed cone shape have better optical performance in visible range than the rounded cone shape which is typical antireflective nanostructures in nature. Based on the observed antireflective behaviors, the flat and low value reflectance spectrum in the visible wavelength range is demonstrated by moth eye mimicking nanostructures on both sides of a glass surface. It is a unique strategy to realize a flat and broadband spectrum in the visible range showing 99% transparency via the appropriate matching of nanopillar height on the front and back sides of glass. The controlled reflection based color tuning on the antireflective and transparent glass is also obtained by adjusting the height of the nanopillar arrays on both sides. The visibility and self-cleaning ability of moth eye mimicking glass are examined for practical applications such as antireflection and self-cleaning.

  10. Efficiency enhancement of silicon solar cells with vertically aligned ZnO nanorod arrays as an antireflective layer

    NASA Astrophysics Data System (ADS)

    Sardana, Sanjay K.; Chandrasekhar, P. S.; Kumar, Rupesh; Komarala, Vamsi K.

    2017-04-01

    Vertically aligned ZnO nanorods grown by the hydrothermal method have been explored as an antireflection layer on polished, textured, and antireflection coating (ARC) coated textured silicon (Si) wafers. Average reflectance (from 380 to 1100 nm) of polished and textured Si wafers reduced from 32 to 9% and 14 to 2%, respectively. With nanorods, multiple light interactions and good optical impedance matching with graded refractive index (effective medium) from air to Si favored for light confinement in Si. Optimized nanorods on ARC coated textured Si cell led to an enhancement of photocurrent from 34.30 to 36.38 mA/cm2 and efficiency from 15.11 to 16.43%.

  11. Bio-inspired fabrication of antireflection nanostructures by replicating fly eyes

    NASA Astrophysics Data System (ADS)

    Huang, Jingyun; Wang, Xudong; Wang, Zhong Lin

    2008-01-01

    In this study, we examined the fine structure of the compound eyes of a household fly and precisely replicated its entire structure using a low-temperature atomic layer deposition technique. The surface of the fly eye is found to be covered by highly packed protuberances, which potentially increases visual efficiency through increased photon capture for a given stimulus. The alumina replica was achieved by removing the fly compound eye template at high temperature, and the alumina coating was crystallized simultaneously. Besides the morphology, the unique antireflection property was also inherited by the alumina replica. By measuring the reflective spectra of the replica, we demonstrated that the alumina replica of a fly eye was an efficient antireflection structure of visible light at an incident angle up to 80°. Such a grating would be particularly useful on a cured corneal surface since it could increase the transmission of incident light through the cornea compared with a smooth surface.

  12. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  13. Optical design of ZnO-based antireflective layers for enhanced GaAs solar cell performance.

    PubMed

    Lee, Hye Jin; Lee, Jae Won; Kim, Hee Jun; Jung, Dae-Han; Lee, Ki-Suk; Kim, Sang Hyeon; Geum, Dae-myeong; Kim, Chang Zoo; Choi, Won Jun; Baik, Jeong Min

    2016-01-28

    A series of hierarchical ZnO-based antireflection coatings with different nanostructures (nanowires and nanosheets) is prepared hydrothermally, followed by means of RF sputtering of MgF2 layers for coaxial nanostructures. Structural analysis showed that both ZnO had a highly preferred orientation along the 〈0001〉 direction with a highly crystalline MgF2 shell coated uniformly. However, a small amount of Al was present in nanosheets, originating from Al diffusion from the Al seed layer, resulting in an increase of the optical bandgap. Compared with the nanosheet-based antireflection coatings, the nanowire-based ones exhibited a significantly lower reflectance (∼2%) in ultraviolet and visible light wavelength regions. In particular, they showed perfect light absorption at wavelength less than approximately 400 nm. However, a GaAs single junction solar cell with nanosheet-based antireflection coatings showed the largest enhancement (43.9%) in power conversion efficiency. These results show that the increase of the optical bandgap of the nanosheets by the incorporation of Al atoms allows more photons enter the active region of the solar cell, improving the performance.

  14. Analysis of an anti-reflecting nanowire transparent electrode for solar cells

    NASA Astrophysics Data System (ADS)

    Zhao, Zhexin; Wang, Ken Xingze; Fan, Shanhui

    2017-03-01

    Transparent electrodes are an important component in many optoelectronic devices, especially solar cells. In this paper, we investigate a nanowire transparent electrode that also functions as an anti-reflection coating for silicon solar cells, taking into account the practical constraints that the electrode is typically encapsulated and needs to be in electric contact with the semiconductor. Numerical simulations show that the electrode can provide near-perfect broadband anti-reflection over much of the frequency range above the silicon band gap for both polarizations while keeping the sheet resistance sufficiently low. To provide insights into the physics mechanism of this broadband anti-reflection, we introduce a generalized Fabry-Perot model, which captures the effects of the higher order diffraction channels as well as the modification of the reflection coefficient of the interface introduced by the nanowires. This model is validated using frequency-domain electromagnetic simulations. Our work here provides design guidelines for nanowire transparent electrode in a device configuration that is relevant for solar cell applications.

  15. MgF2 monolayer as an anti-reflecting material

    NASA Astrophysics Data System (ADS)

    Mahida, H. R.; Singh, Deobrat; Sonvane, Yogesh; Gupta, Sanjeev K.; Thakor, P. B.

    2017-02-01

    The single-layer atomic sheet of magnesium fluoride (MgF2) having 1H and 1T phase structure (hexagonal and tetragonal phase) has been calculated by density functional theory (DFT). Further, we have investigated the structural, electronic and optical properties such as frequency dependent dielectric function, absorption spectra, energy loss spectra, reflectivity, refractive index and optical conductivity of monolayer MgF2 for the direction of parallel and perpendicular electric field polarizations. Our results suggest that monolayer MgF2 provides promising applications in anti-reflection coatings, high-reflective systems and in opto-electronic materials.

  16. Design of two dimensional silicon nanowire arrays for antireflection and light trapping in silicon solar cells

    NASA Astrophysics Data System (ADS)

    Ding, Wuchang; Jia, Rui; Li, Haofeng; Chen, Chen; Sun, Yun; Jin, Zhi; Liu, Xinyu

    2014-01-01

    Silicon nitride coated nanowire arrays have been investigated as an efficient antireflection structure for silicon solar cells. The minimum average reflectance could reach 1.62% under AM1.5 spectrum. Scattering effects of silicon nanowire arrays also result in enhanced absorption in the substrate, and analytical results show that the scattered light can be well trapped in silicon substrate when the back surface is passivated by silicon dioxide. This ultra-low surface reflection property combined with light trapping effect may have potential applications in silicon solar cells with thin substrate.

  17. Durable superhydrophobic and antireflective surfaces by trimethylsilanized silica nanoparticles-based sol-gel processing.

    PubMed

    Manca, Michele; Cannavale, Alessandro; De Marco, Luisa; Aricò, Antonino S; Cingolani, Roberto; Gigli, Giuseppe

    2009-06-02

    We present a robust and cost-effective coating method to fabricate long-term durable superhydrophobic andsimultaneouslyantireflective surfaces by a double-layer coating comprising trimethylsiloxane (TMS) surface-functionalized silica nanoparticles partially embedded into an organosilica binder matrix produced through a sol-gel process. A dense and homogeneous organosilica gel layer was first coated onto a glass substrate, and then, a trimethylsilanized nanospheres-based superhydrophobic layer was deposited onto it. After thermal curing, the two layers turned into a monolithic film, and the hydrophobic nanoparticles were permanently fixed to the glass substrate. Such treated surfaces showed a tremendous water repellency (contact angle = 168 degrees ) and stable self-cleaning effect during 2000 h of outdoor exposure. Besides this, nanotextured topology generated by the self-assembled nanoparticles-based top layer produced a fair antireflection effect consisting of more than a 3% increase in optical transmittance.

  18. Antireflective silica nanoparticle array directly deposited on flexible polymer substrates by chemical vapor deposition.

    PubMed

    Yun, Jungheum; Bae, Tae-Sung; Kwon, Jung-Dae; Lee, Sunghun; Lee, Gun-Hwan

    2012-11-21

    We report the direct coating of a novel antireflective (AR) nanoarray structure of silica nanoparticles on highly flexible polymer substrates by a conventional vacuum coating method using plasma-enhanced chemical vapor deposition. Globular-shaped silica nanoparticles are found to be self-arranged in a periodic pattern on subwavelength scales without the use of artificial assemblies that typically require complicated nanolithography or solution-based nanoparticle fabrication approaches. Highly efficient AR characteristics in the visible spectral range are obtained at optimized refractive indices by controlling the dimensions and average distances of the silica nanoparticle arrays in a level accuracy of tens of nanometers. The AR nanoarrays exhibit sufficient structural durability against the very high strain levels that arise from the flexibility of polymer substrates. This simple coating process provides a cost-effective, high-throughput, room-temperature fabrication solution for producing large-area polymer substrates with AR characteristics.

  19. 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.

  20. Laser processing of solar cells with anti-reflective coating

    DOEpatents

    Harley, Gabriel; Smith, David D.; Dennis, Tim; Waldhauer, Ann; Kim, Taeseok; Cousins, Peter John

    2016-02-16

    Contact holes of solar cells are formed by laser ablation to accommodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thicknesses.

  1. Antireflective properties of pyramidally textured surfaces.

    PubMed

    Deinega, Alexei; Valuev, Ilya; Potapkin, Boris; Lozovik, Yurii

    2010-01-15

    Antireflective properties of pyramidally textured surfaces at normal light incidence are studied by the finite-difference time-domain (FDTD) method. Optimal parameters for the period of the texture and the pyramid height are found. The asymptotic behavior of the reflection coefficient with an increasing height-to-base size ratio for the pyramids is also estimated for two limiting approximations: the effective medium theory (EMT) and geometric optics. For calculations in the geometric optics limit the ray tracing method was applied. The FDTD results for these limits are in agreement with the EMT and with the ray tracing calculations. It was found that the key factor influencing the optimal scatterer size is the character of the substrate tiling by the pyramid bases.

  2. Anti-reflective nanoporous silicon for efficient hydrogen production

    DOEpatents

    Oh, Jihun; Branz, Howard M

    2014-05-20

    Exemplary embodiments are disclosed of anti-reflective nanoporous silicon for efficient hydrogen production by photoelectrolysis of water. A nanoporous black Si is disclosed as an efficient photocathode for H.sub.2 production from water splitting half-reaction.

  3. Sol-gel derived antireflective structures for applications in silicon solar cells

    NASA Astrophysics Data System (ADS)

    Karasiński, Paweł; Skolik, Marcin

    2016-12-01

    This work presents theoretical and experimental results of antireflective coatings (ARCs) obtained for applications in silicon solar cells. ARCs were derived from sol-gel process and dip-coated using silica (SiO2) and titania (TiO2). Theoretical results were obtained using 2×2 transfer matrix calculation method. Technological process of SiO2 and TiO2 thin film fabrication as well as measurement techniques are described in this paper. Strong correlation between theoretical and experimental data is demonstrated. It is shown, that weighted average reflection from a substrate can be reduced ten times with the use of SiO2/TiO2/Si double layer ARCs, when compared to a bare silica substrate.

  4. Review of antireflective surface structures on laser optics and windows.

    PubMed

    Busse, Lynda E; Frantz, Jesse A; Shaw, L Brandon; Aggarwal, Ishwar D; Sanghera, Jasbinder S

    2015-11-01

    We present recent advancements in structured, antireflective surfaces on optics, including crystals for high-energy lasers as well as windows for the infrared wavelength region. These structured surfaces have been characterized and show high transmission and laser damage thresholds, making them attractive for these applications. We also present successful tests of windows with antireflective surfaces that were exposed to simulated harsh environments for the application of these laser systems.

  5. Optimization of optical properties of silicon-based anti-reflective spin-on hardmask materials

    NASA Astrophysics Data System (ADS)

    Kim, Sang Kyun; Cho, Hyeon Mo; Woo, Changsoo; Koh, Sang Ran; Kim, Mi-Young; Yoon, Hui Chan; Lee, Woojin; Shin, Seung-Wook; Kim, Jong-Seob; Chang, Tuwon

    2008-11-01

    In the current semiconductor industry, hardmasks have become essential for successful patterning in many applications. Silicon-based anti-reflective spin-on hardmask (Si-SOH), which can be built by spin-on coating, is desirable in terms of mass production throughput and cost of ownership. As the design rule shrinks, the thickness of photoresist also becomes thinner, which forces the thickness of Si-SOH to be thinner resulting in a tighter thickness margin. In this case, controlling of optical properties of Si-SOH is important in order to obtain low reflectivity in the exposure process. Previously, we reported papers on silicon-based anti-reflective spin-on hardmask materials for 193 nm lithography and immersion ArF lithography. In this paper, the technique for optimization of optical properties, especially n and k values, of Si-SOH is described. To control n and k values, several chromophores were screened and the ratio among them was optimized. Although the amount of chromophores increased and the silicon contents decreased, our etch resistance enhancement technique allowed Si-SOH to have sufficient etch resistance. Characterization of this Si-SOH and lithographic performance using these materials are described in detail.

  6. Controlling etch properties of silicon-based antireflective spin-on hardmask materials

    NASA Astrophysics Data System (ADS)

    Kim, Sang Kyun; Cho, Hyeon Mo; Woo, Changsoo; Koh, Sang Ran; Kim, Mi-Young; Yoon, Hui Chan; Lee, Woojin; Shin, Seung-Wook; Kim, Jong Seob; Chang, Tuwon

    2009-03-01

    In the recent semiconductor mass production, the tri-layer hardmask system has become crucial for successful patterning in many applications. Silicon-based anti-reflective spin-on hardmask (Si-SOH), which can be built by spin-on coating, is desirable in terms of mass production throughput and the overall cost of ownership. As the pattern size shrinks, the thickness of photoresist also becomes thinner, which forces the thickness of Si-SOH to be thinner resulting in a tighter thickness margin. In this case, controlling optical properties of Si-SOH becomes important in order to achieve low reflectivity in the exposure process. In addition, the tri-layer system can be set up more easily when the etch properties of Si-SOH can be controlled. Previously, we reported papers on silicon-based anti-reflective spin-on hardmask materials for 193 nm lithography, immersion ArF lithography, and optimization of optical properties of Si-SOH. In this paper, the technique for controlling etch properties of Si-SOH by a different type of monomer is described. To control etch properties in the same resin platform, the synthesis method was modified. Characterization of the Si-SOH synthesized by the new technique and the lithographic performance using this material are described in detail.

  7. Si/PEDOT:PSS Hybrid Solar Cells with Advanced Antireflection and Back Surface Field Designs

    NASA Astrophysics Data System (ADS)

    Sun, Yiling; Yang, Zhenhai; Gao, Pingqi; He, Jian; Yang, Xi; Sheng, Jiang; Wu, Sudong; Xiang, Yong; Ye, Jichun

    2016-08-01

    Molybdenum oxide (MoO3) is one of most suitable antireflection (AR) layers for silicon/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (Si/PEDOT:PSS) hybrid solar cells due to its well-matched refractive index (2.1). A simulation model was employed to predict the optical characteristics of Si/PEDOT:PSS hybrid solar cells with the MoO3 layers as antireflection coatings (ARCs), as well as to analyze the loss in current density. By adding an optimum thickness of a 34-nm-thick ARC of MoO3 on the front side and an effective rear back surface field (BSF) of phosphorus-diffused N + layer at the rear side, the hybrid cells displayed higher light response in the visible and near infrared regions, boosting a short-circuit current density ( J sc) up to 28.7 mA/cm2. The average power conversion efficiency (PCE) of the Si/PEDOT:PSS hybrid solar cells was thus increased up to 11.90 %, greater than the value of 9.23 % for the reference devices.

  8. Optical properties of chitin: surface-enhanced Raman scattering substrates based on antireflection structures on cicada wings

    NASA Astrophysics Data System (ADS)

    Stoddart, P. R.; Cadusch, P. J.; Boyce, T. M.; Erasmus, R. M.; Comins, J. D.

    2006-02-01

    The transparent wings of some cicada species present ordered arrays of papillary structures with a spacing of approximately 200 nm. These structures serve an antireflection function, with optical transmission peaking at a value of approximately 98% and rising above 90% over a broad band from 450 to 2500 nm. The dimensions of the papillae are comparable to the roughness scale of surface-enhanced Raman scattering (SERS) substrates. SERS measurements performed on silver- and gold-coated wings display enhancement factors of approximately 106 with no apparent background contribution from the wing.

  9. Performance enhancement of pc-Si solar cells through combination of anti-reflection and light-trapping: Functions of AAO nano-grating

    NASA Astrophysics Data System (ADS)

    Wu, Lei; Zhang, Haiming; Qin, Feifei; Bai, Xiaogang; Ji, Ziye; Huang, Dan

    2017-02-01

    Anodic aluminium oxide (AAO) nanogratings are experimentally applied to polycrystalline silicon (pc-Si) solar cells at front surface to improve the light coupling. On the basis of the Fresnel Reflection Principle, the primary reflection loss can be reduced by multi-layer dielectric film with varing refactive index. And this multi-layer film is regarded as anti-reflection coating. An efficient light-trapping structure is significant in absorption enhancement of long wavelength band (around 900-1100 nm) for silicon solar cells. In this paper, we put AAO nanogratings on the front side of pc-Si solar cells to serve as anti-reflecting coating and light-trapping structure. The operation leads to light absorption enhancement eventually. Thanks to AAO nano-grating's structure parameters, the anti-reflecting and light-trapping effects are changeable. This is discussed in three aspects: AAO lattice period, AAO thickness and its pore diameter. Optical interaction between AAO nanograting and Ag electrodes is also discussed. We find an increase of short-circuit current density (1.32 mA/cm2) with SiNx:H/AAO complex coating. The relative power conversion efficiency obtains a growth about 2.2% points. Additionally, AAO nanogratings may facilitate carrier separation. This improves the performance of pc-Si solar cells in electrical aspect.

  10. Broadband-antireflective hybrid nanopillar array for photovoltaic application

    SciTech Connect

    Watanabe, Keiji Yamamoto, Jiro; Tsuchiya, Ryuta

    2015-08-28

    Subwavelength structures such as nanopillars, nanoholes, and nanodomes have recently attracted considerable attention as antireflective structures for solar cells. Recent studies on the optical property of nanopillar array revealed that the reflection minimum is related to the diameter, the pitch, and the height of nanopillars. Here, we investigate the “hybrid” nanopillar array, which is composed of different diameters of nanopillars. Finite differential time domain simulations revealed that the photogeneration in a hybrid nanopillar array is spatially heterogeneous: carriers are generated mainly in the narrower pillars for short-wavelength incident light and in the thicker pillars for long-wavelength light, respectively. Hybrid silicon nanopillar arrays fabricated by using electron beam lithography and dry etching show excellent broadband antireflection property. Hybrid nanopillar array is thus highly promising for next-generation antireflection for photovoltaic applications.

  11. A versatile route to polymer-reinforced, broadband antireflective and superhydrophobic thin films without high-temperature treatment.

    PubMed

    Ren, Tingting; Geng, Zhi; He, Junhui; Zhang, Xiaojie; He, Jin

    2017-01-15

    Broadband high transmittance, good mechanical robustness as well as simple and low temperature fabrication are three important aspects that dictate the practical applications of superhydrophobic thin films, especially on organic substrates. However, it has proved difficult to meet these challenges. In the present work, superhydrophobic thin films were prepared by first dip-coating solid silica nanoparticles, then spray-coating hollow silica nanoparticles, followed by spray-coating mesoporous silica nanosheets & poly(vinyl alcohol) (PVA), and eventually chemical vapor deposition of 1H,1H,2H,2H-perflurooctyltriethoxysilane (POTS) at 90°C. The optimized thin film has a maximum transmittance of 96.0% in the wavelength range of 300-2500nm and a WCA of 164° and a RA of 1°. The thin film also shows good mechanical robustness toward water droplet impact test, sand impact abrasion test and tape adhesion tests, which results from PVA as a binder, the formation of covalent bond between the hydroxyl group of PVA and the ethoxy group of POTS and the chemical inertness of CC, CF bonds of POTS molecules. To our best knowledge, it is the first example where antireflective and superhydrophobic thin films of excellent mechanical robustness were realized at low temperature on organic substrates (PMMA, PC). The current work would provide a promising route to meet the challenges in practical applications simultaneously posed by the requirements of broadband antireflection, good mechanical robustness as well as simple and low temperature fabrication of superhydrophobic thin films.

  12. Fabrication and performance of polymer-nanocomposite anti-reflective thin films deposited by RIR-MAPLE

    SciTech Connect

    Singaravelu, S.; Mayo, D. C.; Park, H-. K.; Schriver, K. E.; Klopf, John M.; Kelley, Michael J.; Haglund, R. F.

    2014-07-01

    Design of polymer anti-reflective (AR) optical coatings for plastic substrates is challenging because polymers exhibit a relatively narrow range of refractive indices. Here, we report synthesis of a four-layer AR stack using hybrid polymer: nanoparticle materials deposited by resonant infrared matrix-assisted pulsed laser evaporation. An Er: YAG laser ablated frozen solutions of a high-index composite containing TiO2 nanoparticles and poly(methylmethacrylate) (PMMA), alternating with a layer of PMMA. The optimized AR coatings, with thicknesses calculated using commercial software, yielded a coating for polycarbonate with transmission over 97 %, scattering <3 %, and a reflection coefficient below 0.5 % across the visible range, with a much smaller number of layers than would be predicted by a standard thin film calculation. The TiO2 nanoparticles contribute more to the enhanced refractive index of the high-index layers than can be accounted for by an effective medium model of the nanocomposite.

  13. Self-organized, effective medium Black Silicon for infrared antireflection

    NASA Astrophysics Data System (ADS)

    Steglich, Martin; Käsebier, Thomas; Schrempel, Frank; Kley, Ernst-Bernhard; Tünnermann, Andreas

    2015-03-01

    Statistical Black Silicon antireflection structures for the mid-infrared spectral region, fabricated by Inductively Coupled Plasma Reactive Ion Etching, are investigated. Upon variation of etch duration scaling of the structure morphologies is observed and related to the optical losses in specular transmittance. By means of statistical morphology analysis, an effective medium criterion for the examined structures is derived that can be used as a design rule for maximizing sample transmittance at a given wavelength. To obtain Black Silicon antireflection structures with elevated bandwidth, an additional deep-etch step is proposed and demonstrated.

  14. [Research on the photoelectric conversion efficiency of grating antireflective layer solar cells].

    PubMed

    Zhong, Hui; Gao, Yong-Yi; Zhou, Ren-Long; Zhou, Bing-ju; Tang, Li-qiang; Wu, Ling-xi; Li, Hong-jian

    2011-07-01

    A numerical investigation of the effect of grating antireflective layer structure on the photoelectric conversion efficiency of solar cells was carried out by the finite-difference time-domain method. The influence of grating shape, height and the metal film thickness coated on grating surface on energy storage was analyzed in detail. It was found that the comparison between unoptimized and optimized surface grating structure on solar cells shows that the optimization of surface by grating significantly increases the energy storage capability and greatly improves the efficiency, especially of the photoelectric conversion efficiency and energy storage of the triangle grating. As the film thickness increases, energy storage effect increases, while as the film thickness is too thick, energy storage effect becomes lower and lower.

  15. Mechanically robust, thermally stable, broadband antireflective, and superhydrophobic thin films on glass substrates.

    PubMed

    Xu, Ligang; Geng, Zhi; He, Junhui; Zhou, Gang

    2014-06-25

    In this study, we developed a simple and versatile strategy to fabricate hierarchically structured lotus-leaf-like superhydrophobic thin films. The thin films are broadband antireflective, and the average transmittance of coated glass substrates reached greater than 95% in the wavelength range of 530-1340 nm, in contrast to 92.0% for bare glass substrate. The thin film surface shows a static water contact angle of 162° and a sliding angle less than 4°. Moreover, the thin film is thermally stable up to 300 °C, and shows remarkable stability against strong acid, strong alkali, water drop impact, and sand impact abrasion, while retaining its superhydrophobicity. Further, the thin film can pass the 3H pencil hardness test. The current approach may open a new avenue to a variety of practical applications, including windshields, eyeglasses, windows of high rise buildings and solar cells, etc.

  16. Hexagonal arrays of round-head silicon nanopillars for surface anti-reflection applications

    NASA Astrophysics Data System (ADS)

    Yan, Wensheng; Dottermusch, Stephan; Reitz, Christian; Richards, Bryce S.

    2016-10-01

    We designed and fabricated an anti-reflection surface of hexagonal arrays of round-head silicon nanopillars. The measurements show a significant reduction in reflectivity across a broad spectral range. However, we then grew a conformal titanium dioxide coating via atomic layer deposition to achieve an extremely low weighted average reflection of 2.1% over the 460-1040 nm wavelength range. To understand the underlying reasons for the reduced reflectance, the simulations were conducted and showed that it is due to strong forward scattering of incident light into the silicon substrate. The calculated normalized scattering cross section demonstrates a broadband distribution feature, and the peak has a red-shift to longer wavelengths. Finally, we report two-dimensional weighted average reflectance as a function of both wavelength and angle of incidence and present the resulting analysis contour map.

  17. Antireflection and SiO2 Surface Passivation by Liquid-Phase Chemistry for Efficient Black Silicon Solar Cells: Preprint

    SciTech Connect

    Yuan, H. C.; Oh, J.; Zhang, Y.; Kuznetsov, O. A.; Flood, D. J.; Branz, H. M.

    2012-06-01

    We report solar cells with both black Si antireflection and SiO2 surface passivation provided by inexpensive liquid-phase chemistry, rather than by conventional vacuum-based techniques. Preliminary cell efficiency has reached 16.4%. Nanoporous black Si antireflection on crystalline Si by aqueous etching promises low surface reflection for high photon utilization, together with lower manufacturing cost compared to vacuum-based antireflection coating. Ag-nanoparticle-assisted black Si etching and post-etching chemical treatment recently developed at NREL enables excellent control over the pore diameter and pore separation. Performance of black Si solar cells, including open-circuit voltage, short-circuit current density, and blue response, has benefited from these improvements. Prior to this study, our black Si solar cells were all passivated by thermal SiO2 produced in tube furnaces. Although this passivation is effective, it is not yet ideal for ultra-low-cost manufacturing. In this study, we report, for the first time, the integration of black Si with a proprietary liquid-phase deposition (LPD) passivation from Natcore Technology. The Natcore LPD forms a layer of <10-nm SiO2 on top of the black Si surface in a relatively mild chemical bath at room temperature. We demonstrate black Si solar cells with LPD SiO2 with a spectrum-weighted average reflection lower than 5%, similar to the more costly thermally grown SiO2 approach. However, LPD SiO2 provides somewhat better surface-passivation quality according to the lifetime analysis by the photo-conductivity decay measurement. Moreover, black Si solar cells with LPD SiO2 passivation exhibit higher spectral response at short wavelength compared to those passivated by thermally grown SiO2. With further optimization, the combination of aqueous black Si etching and LPD could provide a pathway for low-cost, high-efficiency crystalline Si solar cells.

  18. Properties of conductive coatings for thermal control mirrors and solar cell covers

    NASA Technical Reports Server (NTRS)

    Joslin, D. E.; Kan, H. K. A.

    1975-01-01

    Conductive transparent coatings applied to the dielectric surfaces of a spacecraft offer the possibility of distributing charge uniformly over the entire spacecraft surface. Optical and electrical measurements of such a coating as a function of temperature are described. These results are used in considering the impact of a conductive coating on the absorptance of thermal control mirrors and on the transmittance of solar cell cover glass, which can be improved by the application of an antireflection coating.

  19. Anti-reflective device having an anti-reflective surface formed of silicon spikes with nano-tips

    NASA Technical Reports Server (NTRS)

    Bae, Youngsam (Inventor); Manohara, Harish (Inventor); Mobasser, Sohrab (Inventor); Lee, Choonsup (Inventor)

    2011-01-01

    Described is a device having an anti-reflection surface. The device comprises a silicon substrate with a plurality of silicon spikes formed on the substrate. A first metallic layer is formed on the silicon spikes to form the anti-reflection surface. The device further includes an aperture that extends through the substrate. A second metallic layer is formed on the substrate. The second metallic layer includes a hole that is aligned with the aperture. A spacer is attached with the silicon substrate to provide a gap between an attached sensor apparatus. Therefore, operating as a Micro-sun sensor, light entering the hole passes through the aperture to be sensed by the sensor apparatus. Additionally, light reflected by the sensor apparatus toward the first side of the silicon substrate is absorbed by the first metallic layer and silicon spikes and is thereby prevented from being reflected back toward the sensor apparatus.

  20. Self-organized, effective medium black silicon antireflection structures for silicon optics in the mid-infrared

    NASA Astrophysics Data System (ADS)

    Steglich, Martin; Käsebier, Thomas; Kley, Ernst-Bernhard; Tünnermann, Andreas

    2016-09-01

    Thanks to its high quality and low cost, silicon is the material of choice for optical devices operating in the mid-infrared (MIR; 2 μm to 6 μm wavelength). Unfortunately in this spectral region, the refractive index is comparably high (about 3.5) and leads to severe reflection losses of about 30% per interface. In this work, we demonstrate that self-organized, statistical Black Silicon structures, fabricated by Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE), can be used to effectively suppress interface reflection. More importantly, it is shown that antireflection can be achieved in an image-preserving, non-scattering way. This enables Black Silicon antireflection structures (ARS) for imaging applications in the MIR. It is demonstrated that specular transmittances of 97% can be easily achieved on both flat and curved substrates, e.g. lenses. Moreover, by a combined optical and morphological analysis of a multitude of different Black Silicon ARS, an effective medium criterion for the examined structures is derived that can also be used as a design rule for maximizing sample transmittance in a desired wavelength range. In addition, we show that the mechanical durability of the structures can be greatly enhanced by coating with hard dielectric materials like diamond-like carbon (DLC), hence enabling practical applications. Finally, the distinct advantages of statistical Black Silicon ARS over conventional AR layer stacks are discussed: simple applicability to topological substrates, absence of thermal stress and cost-effectiveness.

  1. Entry and exit facet laser damage of optical windows with random antireflective surface structures

    NASA Astrophysics Data System (ADS)

    Sapkota, Gopal; Case, Jason R.; Potter, Matthew G.; Busse, Lynda E.; Shaw, L. Brandon; Sanghera, Jasbinder S.; Aggarwal, Ishwar D.; Poutous, Menelaos K.

    2016-12-01

    Nanosecond duration, high intensity and high average power laser pulses induce damage on uncoated optics, due to localized field enhancement at the exit surface of the components. Anti-reflection (AR) coated optics, due to their (multiple) thin film boundaries, have similar field enhancement regions, which lead to laser damage on both entry and exit sides. Nano-scale structured optical interfaces with AR performance (ARSS) have been widely demonstrated, and found to have higher laser damage resistance than conventional AR coatings. Comprehensive tests of optical entry and exit structured-surface laser damage using nanosecond pulses for ARSS are not widely available. We measured the laser damage of random anti-reflective surface structures (rARSS), on planar, optical quality, fused silica substrates, using single 6-8ns duration pulses at 1064 nm wavelength. The single-sided rARSS substrates were optimized for Fresnel reflectance suppression at 1064 nm, and the measured transmittance at normal incidence was increased by 3.2%, with a possible theoretical maximum of 3.5%. The high energy laser beam was focused to increase the incident intensity, in order to probe values above and below the damage thresholds reported in the literature. The source laser Q-switch durations were used to directly control incident fluence. Multiple locations were tested for each Q-switch setting, to build a statistical relationship between the fluence and damaging events. Single-sided, AR random surface structured substrates were tested, using entry and exit side orientations, to determine any effects the random structures may have in the damage induced by the field enhancement on the exit side. We found that the AR randomly structured surfaces have a higher resistance, to the onset of laser damage, when they are located at the entry (structured) side of the substrates. In comparison, when the same AR random structures are in the beam exit side of the substrates, the onset of laser damage

  2. A wide-angle antireflection surface for the visible spectrum.

    PubMed

    Päivänranta, B; Saastamoinen, T; Kuittinen, M

    2009-09-16

    A surface consisting of periodically arranged nanopyramids producing wide-angle broad-band antireflection properties is presented. The reflectance of silicon dioxide is reduced below 0.45% over the visible spectral range (380-760 nm) for viewing angles from 0 degrees to 40 degrees . The surface is designed by using rigorous diffraction theory and fabricated first in silicon by exploiting its strong crystalline orientation and by using the wet etching process. The structure is transferred from silicon to transparent silicon dioxide by using nano-imprint lithography and proportional reactive ion etching.

  3. Method and tool to reverse the charges in anti-reflection films used for solar cell applications

    DOEpatents

    Sharma, Vivek; Tracy, Clarence

    2017-01-31

    A method is provided for making a solar cell. The method includes providing a stack including a substrate, a barrier layer disposed on the substrate, and an anti-reflective layer disposed on the barrier layer, where the anti-reflective layer has charge centers. The method also includes generating a corona with a charging tool and contacting the anti-reflective layer with the corona thereby injecting charge into at least some of the charge centers in the anti-reflective layer. Ultra-violet illumination and temperature-based annealing may be used to modify the charge of the anti-reflective layer.

  4. Optical coatings for metamaterials (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Jen, Yi-Jun

    2016-09-01

    Optical coatings have been referred as thin films that create interference effect to change optical properties of substrates. The most common applications of optical thin films are anti-reflection coatings, high reflective coatings, beamsplitter coatings, and bandpass filter coatings. In the recent development of metamaterials, the optical coatings also play a critical role in design, fabrication and measurement. In fabrication, glancing angle deposition has been applied to grow slanted metal nanorod arrays. The associated longitudinal plasmon and transverse plasmon modes under linear polarized illuminations are induced and generate anisotropic refractive index and extinction coefficient. Strong birefringence of a silver nanorod array reveals positive and negative real refractive indices exist for two orthogonal linear polarization states. Recently, negative index materials and hyperbolic metamaterials are realized as multilayers comprising subwavelength-scale metal and dielectric films alternatively. From the view of optical coatings, the design of optical edge filters can be applied to arrange the metal-dielectric multilayer as a symmetrical film sack to perform equivalent complex admittance and refractive index. On the other hand, the traditional admittance diagram used in design of antireflection and bandpass filters can be applied to induce the transmission of a negative index multilayer. The admittance loci of metal films are designed to be huge contours in the admittance diagram to reduce the energy loss in metal films. Five-layered symmetrical film stack and seven-layered symmetrical film stack are shown here to present as new bandpass filters with negative real refractive indices.

  5. Disordered antireflective subwavelength structures using Ag nanoparticles on fused silica windows.

    PubMed

    Shang, Peng; Xiong, Sheng Ming; Deng, Qi Ling; Shi, Li Fang; Zhang, Mian

    2014-10-10

    In this paper, we have demonstrated an effective method for fabricating disordered subwavelength structures (d-SWSs) on fused silica using thermal dewetted Ag nanoparticles at lower temperatures (<300°C) with a vacuum. Theoretically and experimentally, we investigate the effects of the film thickness, annealing temperature, and etching time on the antireflective properties of the d-SWS arrays. The measured data and calculated results obtained by rigorous coupled-wave analysis exhibit reasonably similar tendencies. For the sample with a 10-nm-thick Ag film, good optical transmission characteristics (on one side, T(ave)∼95.6%) over a wide wavelength region of 500-1300 nm were obtained, and a maximum value of ∼96% at a wavelength of 850 nm was also obtained. Furthermore, the d-SWSs exhibit excellent optical and thermal stability at high temperatures of 800°C and 1000°C compared to a conventional Ta2O5/SiO2 multilayer coating.

  6. Contamination resistant antireflection nano-textures in fused silica for laser optics

    NASA Astrophysics Data System (ADS)

    Hobbs, Douglas S.; MacLeod, Bruce D.; Sabatino, Ernest; Britten, Jerald A.; Stolz, Christopher J.

    2013-11-01

    Anti-reflecting (AR) surface relief nano-textures have been integrated with fused silica diffraction gratings to demonstrate the potential of stable diffractive 3ω beam samplers with increased energy to target at the National Ignition Facility (NIF). TelAztec's AR texturing process was used to etch Random-type AR (RAR) microstructures in sub-scale NIF Grating Debris Shields consisting of large pitch, shallow line gratings. This superposition yielded the desired ~3.5% increase in zero-order transmission uniformly over the full aperture without compromising the grating function. Another fused silica window fabricated with RAR nano-textures in both faces for a 3ω (351nm) transmission of 99.5%, was subjected to capillary condensation tests to evaluate the resistance of the RAR texture to the adsorption of organic compounds. It was found that for a one day exposure time to a surrogate suite of organic contaminants, the RAR textured fused silica surfaces adsorbed less than one fourth the amount of organic contaminants found on a NIF baseline hardened sol-gel AR coated optic. In two additional exposure cycles, further RAR process refinement reduced the amount of adsorbed organics to a level nearly 200 times below the current NIF baseline. Significantly, the 3ω transmission of the RAR textured window remained unchanged after all three exposure cycles, whereas the sol-gel coated windows showed losses up to 4.9% for the highest contaminant concentration. Large beam pulsed laser damage testing of RAR textured fused silica windows was conducted with the Optical Sciences Laser (OSL) at NIF. The RAR sample damage resistance was found to be equivalent to the current NIF baseline - even after multiple aggressive chemical cleaning cycles. Lastly, a series of RAR textured and sol-gel AR coated windows were subjected to commercial 3ω pulsed laser damage testing at Quantel. The results indicate an average RAR damage threshold of 26 J/cm2, a level about 80% of the two NIF fused

  7. Laser damage resistant anti-reflection microstructures in Raytheon ceramic YAG, sapphire, ALON, and quartz

    NASA Astrophysics Data System (ADS)

    Hobbs, Douglas S.; MacLeod, Bruce D.; Sabatino, Ernest, III; Hartnett, Thomas M.; Gentilman, Richard L.

    2011-06-01

    A study of the laser induced damage threshold (LiDT) of anti-reflection (AR) microstructures (ARMs) built in the end facets of metal ion doped yttrium aluminum garnet (YAG) laser gain material, has been conducted. Test samples of undoped and ytterbium-doped polycrystalline YAG produced by Raytheon Company were processed with ARMs in one surface and subjected to standardized pulsed LiDT testing at the near-infrared (NIR) wavelength of 1064nm. As received YAG samples with a simple commercial polish were also submitted to the damage tests for comparison, along with YAG samples that were treated with a single layer thin-film AR coating designed for maximum transmission at 1064nm. Additional samples of single crystal sapphire and quartz, and polycrystalline ALONTM windows were prepared with thin-film AR coatings and ARMs textures to expand the 1064nm laser damage testing to other important NIR transmitting materials. It was found that the pulsed laser damage resistance of ARMs textured ceramic YAG windows is 11 J/cm2, a value that is 43% higher than untreated ceramic YAG windows, suggesting that ARMs fabrication removed residual sub-surface damage, a factor that has been shown to be important for increasing the damage resistance of an optic. This conclusion is also supported by the high damage threshold values found with the single layer AR coatings on ceramic YAG where the coatings may have shielded the sub-surface polishing damage. Testing results for the highly polished sapphire windows also support the notion that better surface preparation produces higher damage resistance. The damage threshold for untreated sapphire windows exceeded 32 J/cm2 for one sample with an average of 27.5 J/cm2 for the two samples tested. The ARMs-treated sapphire windows had similar damage thresholds as the untreated material, averaging 24.9 J/cm2, a value 1.5 to 2 times higher than the damage threshold of the thin film AR coated sapphire windows.

  8. Novel anti-reflection technology for GaAs single-junction solar cells using surface patterning and Au nanoparticles.

    PubMed

    Kim, Youngjo; Lam, Nguyen Dinh; Kim, Kangho; Kim, Sangin; Rotermund, Fabian; Lim, Hanjo; Lee, Jaejin

    2012-07-01

    Single-junction GaAs solar cell structures were grown by low-pressure MOCVD on GaAs (100) substrates. Micro-rod arrays with diameters of 2 microm, 5 microm, and 10 microm were fabricated on the surfaces of the GaAs solar cells via photolithography and wet chemical etching. The patterned surfaces were coated with Au nanoparticles using an Au colloidal solution. Characteristics of the GaAs solar cells with and without the micro-rod arrays and Au nanoparticles were investigated. The short-circuit current density of the GaAs solar cell with 2 microm rod arrays and Au nanoparticles increased up to 34.9% compared to that of the reference cell without micro-rod arrays and Au nanoparticles. The conversion efficiency of the GaAs solar cell that was coated with Au nanoparticles on the patterned surface with micro-rod arrays can be improved from 14.1% to 19.9% under 1 sun AM 1.5G illumination. These results show that micro-rod arrays and Au nanoparticle coating can be applied together in surface patterning to achieve a novel cost-effective anti-reflection technology.

  9. Application of physical gradient index (Moth-Eye) structures to ALON windows as a durable anti-reflection treatment

    NASA Astrophysics Data System (ADS)

    Agarwal, Neeta; Goldman, Lee M.; Sastri, Suri A.; Ondercin, Robert J.; Kobrin, Paul

    2009-05-01

    The optical performance of windows and domes are subject to degradation from rain and sand erosion damage in harsh flight environments. While durable window and dome materials, such as ALON®, spinel and sapphire are more or less impervious to rain and sand erosion damage in the captive carry environments, the coatings use to provide antireflection (AR) function are not. Rain and/or sand erosion damage of the outer AR coating leads to degradation of the windows optical performance, even when the underlying window itself is not damaged. Surmet has been working on design and development of physical gradient index (Moth- Eye) structures based AR surfaces etched directly into the surface of the ALON substrate. By eliminating the need for less durable coating materials, these structures offer high optical performance without compromising durability. The difficulty of this approach is that the same durability that makes ALON impervious to erosion damage makes it very difficult to etch. Processes have been developed at Surmet which facilitate the etching of fine deep features into ALON surfaces required for broadband AR function. Recent results will be presented.

  10. Use of ZnO as antireflective, protective, antibacterial, and biocompatible multifunction nanolayer of thermochromic VO2 nanofilm for intelligent windows

    NASA Astrophysics Data System (ADS)

    Zhou, Huaijuan; Li, Jinhua; Bao, Shanhu; Li, Jian; Liu, Xuanyong; Jin, Ping

    2016-02-01

    A multifunctional VO2/ZnO bilayer film is designed and deposited by magnetron sputtering apparatus. The integration of the antireflective, antioxidative and anti-corrosion functions, and antibacterial performance makes the heterostructure film a promising candidate in the energy-saving smart window. The ZnO thin film as the antireflection layer can markedly boost the solar regulation efficiency (ΔTsol) from 7.7% to 12.2% and possesses excellent luminous transmittance (Tlum-L = 50.3%) in the low-temperature semiconductor phase. The ZnO layer as the protection barrier can not only protect VO2 thin film from oxidation to much toxic V2O5, but also decrease the release of V ions. Besides, the synergistic effect of releasing killing by Zn2+ ions and contact killing by ZnO NPs makes ZnO thin film an outstanding antibacterial coating. In terms of the biological safety, ZnO coating with appropriate film thickness can effectively attenuate the cytotoxicity of VO2 on human HIBEpiC cells. We hope this work can provide new insights for better designing of novel multifunctional VO2-based intelligent energy-saving windows.

  11. Coated fiber tips for optical instrumentation

    NASA Astrophysics Data System (ADS)

    Barton, John B.; Chanda, Sheetal; Locknar, Sarah A.; Carver, Gary E.

    2016-03-01

    Compact optical systems can be fabricated by integrating coatings on fiber tips. Examples include fiber lasers, fiber interferometers, fiber Raman probes, fiber based spectrometers, and anti-reflected endoscopes. These interference filters are applied to exposed tips - either connectorized or cleaved. Coatings can also be immersed within glass by depositing on one tip and connecting to another uncoated tip. This paper addresses a fiber spectrometer for multispectral imaging - useful in several fields including biomedical scanning, flow cytometry, and remote sensing. Our spectrometer integrates serial arrays of reflecting fiber tips, delay lines between these elements, and a single element detector.

  12. Optimization of contaminated oxide inversion layer solar cell. [considering silicon oxide coating

    NASA Technical Reports Server (NTRS)

    Call, R. L.

    1976-01-01

    Contaminated oxide cells have been fabricated with efficiencies of 8.6% with values of I sub sc = 120 ma, V sub oc = .54 volts, and curve factor of .73. Attempts to optimize the fabrication step to yield a higher output have not been successful. The fundamental limitation is the inadequate antireflection coating afforded by the silicon dioxide coating used to hold the contaminating ions. Coatings of SiO, therefore, were used to obtain a good antireflection coating, but the thinness of the coatings prevented a large concentration of the contaminating ions, and the cells was weak. Data of the best cell were .52 volts V sub oc, 110 ma I sub sc, .66 CFF and 6.7% efficiency.

  13. Direct laser diode welding system with anti-reflection unit

    NASA Astrophysics Data System (ADS)

    Nagayasu, Doukei; Wang, Jing-bo

    2003-11-01

    A high power laser diode system for welding is widely known. However, the reliability and the reasonability are required by an industrial market. Reliability, especially lifetime, mainly depends on the temperature of laser diode (LD) and it might be rise if LD would receive reflection from welding point. This paper conducted the measurement of the reflection during welding by applying 1/4 wavelength plate and PBS. Results indicated the reflection during welding was inevitable. We developed a prototype high power laser diode system, which equipped an anti-reflection unit, to improve the reliability. The system traveled 3m/min and its bead width was 1.2 mm for 1.5 mm Al (A5052) under the spot size 2.7 x 0.6 mm FWHM. Additionally, we started to develop fast and slow collimation lenses for LD to realize a reasonale price for system The brief evaluation of fast collimation lenses was also reported.

  14. Tailoring room temperature photoluminescence of antireflective silicon nanofacets

    SciTech Connect

    Basu, Tanmoy; Kumar, M.; Ghatak, J.; Som, T.; Kanjilal, A.; Sahoo, P. K.

    2014-09-21

    In this paper, a fluence-dependent antireflection performance is presented from ion-beam fabricated nanofaceted-Si surfaces. It is also demonstrated that these nanofacets are capable of producing room temperature ultra-violet and blue photoluminescence which can be attributed to inter-band transitions of the localized excitonic states of different Si-O bonds at the Si/SiO{sub x} interface. Time-resolved photoluminescence measurements further confirm defect-induced radiative emission from the surface of silicon nanofacets. It is observed that the spectral characteristics remain unchanged, except an enhancement in the photoluminescence intensity with increasing ion-fluence. The increase in photoluminescence intensity by orders of magnitude stronger than that of a planar Si substrate is due to higher absorption of incident photons by nanofaceted structures.

  15. Silicon Nanotips Antireflection Surface for Micro Sun Sensor

    NASA Technical Reports Server (NTRS)

    Bae, Sam Y.; Lee, Choonsup; Mobasser, Sohrab; Manohara, Harish

    2006-01-01

    We have developed a new technique to fabricate antireflection surface using silicon nano-tips for use on a micro sun sensor for Mars rovers. We have achieved randomly distributed nano-tips of radius spanning from 20 nm to 100 nm and aspect ratio of 200 using a two-step dry etching process. The 30(deg) specular reflectance at the target wavelength of 1 (mu)m is only about 0.09 %, nearly three orders of magnitude lower than that of bare silicon, and the hemispherical reflectance is 8%. By changing the density and aspect ratio of these nanotips, the change in reflectance is demonstrated. Using surfaces covered with these nano-tips, the critical problem of ghost images that are caused by multiple internal reflections in a micro sun sensor was solved.

  16. Moth's eye anti-reflection gratings on germanium freeform surfaces

    NASA Astrophysics Data System (ADS)

    Liu, Meng; Shultz, Jason A.; Owen, Joseph D.; Davies, Matthew A.; Suleski, Thomas J.

    2014-09-01

    Germanium is commonly used for optical components in the infrared, but the high refractive index of germanium causes significant losses due to Fresnel reflections. Anti-reflection (AR) surfaces based on subwavelength "moth's eye" gratings provide one means to significantly increase optical transmission. As found in nature, these gratings are conformal to the curved surfaces of lenslets in the eye of the moth. Engineered optical systems inspired by biological examples offer possibilities for increased performance and system miniaturization, but also introduce significant challenges to both design and fabrication. In this paper, we consider the design and fabrication of conformal moth's eye AR structures on germanium freeform optical surfaces, including lens arrays and Alvarez lenses. Fabrication approaches and limitations based on both lithography and multi-axis diamond machining are considered. Rigorous simulations of grating performance and approaches for simulation of conformal, multi-scale optical systems are discussed.

  17. Exploring anti-reflection modes in disordered media.

    PubMed

    Kim, Moonseok; Choi, Wonjun; Yoon, Changhyeong; Kim, Guang Hoon; Kim, Seung-hyun; Yi, Gi-Ra; Park, Q-Han; Choi, Wonshik

    2015-05-18

    Sensing and manipulating targets hidden under scattering media are universal problems that take place in applications ranging from deep-tissue optical imaging to laser surgery. A major issue in these applications is the shallow light penetration caused by multiple scattering that reflects most of incident light. Although advances have been made to eliminate image distortion by a scattering medium, dealing with the light reflection has remained unchallenged. Here we present a method to minimize reflected intensity by finding and coupling light into the anti-reflection modes of a scattering medium. In doing so, we achieved more than a factor of 3 increase in light penetration. Our method of controlling reflected waves makes it readily applicable to in vivo applications in which detector sensors can only be positioned at the same side of illumination and will therefore lay the foundation of advancing the working depth of many existing optical imaging and treatment technologies.

  18. Biomimetic ‘moth-eye’ anti-reflection boundary for graphene plasmons circuits

    NASA Astrophysics Data System (ADS)

    Zhu, B.; Ren, G.; Cryan, M. J.; Gao, Y.; Li, H.; Wang, Q.; Wan, C.; Jian, S.

    2015-12-01

    In this paper we propose the anti-reflection boundary design for planar graphene plasmons (GPs) circuits based on biomimetic moth-eye structures. The anti-reflection functionalities are investigated by analytical effective medium theory combined with transfer matrix method and numerical finite element method. Both analytical and numerical methods have shown that average reflection losses of 1% can be achieved within the mid-infrared region. Moreover, for plasmons with a very wide incident angle, the performance of such anti-reflection boundary could still be maintained, achieving less than 1% reflection up to 60° incident angle. The proposed moth-eye anti-reflection boundary would be helpful for the future development of high integration GPs circuits.

  19. The HMDS Coating Flaw Removal Tool

    SciTech Connect

    Monticelli, M V; Nostrand, M C; Mehta, N; Kegelmeyer, L; Johnson, M A; Fair, J; Widmayer, C

    2008-10-24

    In many high energy laser systems, optics with HMDS sol gel antireflective coatings are placed in close proximity to each other making them particularly susceptible to certain types of strong optical interactions. During the coating process, halo shaped coating flaws develop around surface digs and particles. Depending on the shape and size of the flaw, the extent of laser light intensity modulation and consequent probability of damaging downstream optics may increase significantly. To prevent these defects from causing damage, a coating flaw removal tool was developed that deploys a spot of decane with a syringe and dissolves away the coating flaw. The residual liquid is evacuated leaving an uncoated circular spot approximately 1mm in diameter. The resulting uncoated region causes little light intensity modulation and thus has a low probability of causing damage in optics downstream from the mitigated flaw site.

  20. Nature Inspired Surface Coatings

    NASA Astrophysics Data System (ADS)

    Rubner, Michael

    2011-04-01

    Materials Scientists more and more are looking to nature for clues on how to create highly functional surface coatings with exceptional properties. The fog harvesting capabilities of the Namib Desert beetle, the beautiful iridescent colors of the hummingbird, and the super water repellant abilities of the Lotus leaf are but a few examples of the amazing properties developed over many years in the natural world. Nature also makes extensive use of the pH-dependent behavior of weak functional groups such as carboxylic acid and amine functional groups. This presentation will explore synthetic mimics to the nano- and microstructures responsible for these fascinating properties. For example, we have demonstrated a pH-induced porosity transition that can be used to create porous films with pore sizes that are tunable from the nanometer scale to the multiple micron scale. The pores of these films, either nano- or micropores, can be reversibly opened and closed by changes in solution pH. The ability to engineer pH-gated porosity transitions in heterostructured thin films has led to the demonstration of broadband anti-reflection coatings that mimic the anti-reflection properties of the moth eye and pH-tunable Bragg reflectors with a structure and function similar to that found in hummingbird wings and the Longhorn beetle. In addition, the highly textured honeycomb-like surfaces created by the formation of micron-scale pores are ideally suited for the creation of superhydrophobic surfaces that mimic the behavior of the self-cleaning lotus leaf. The development of synthetic "backbacks" on immune system cells that may one day ferry drugs to disease sites will also be discussed.

  1. Development of high-throughput silicon lens and grism with moth-eye anti-reflection structure

    NASA Astrophysics Data System (ADS)

    Kamizuka, Takafumi; Miyata, Takashi; Sako, Shigeyuki; Imada, Hiroaki; Ohsawa, Ryou; Asano, Kentaro; Uchiyama, Mizuho; Okada, Kazushi; Uchiyama, Masahito; Wada, Takehiko; Nakagawa, Takao; Nakamura, Tomohiko; Sakon, Itsuki; Onaka, Takashi

    2014-07-01

    Anti-reflection (AR) is very important for high-throughput optical elements. The durability against cooling is required for the AR structure in the cryogenic optics used for mid-infrared astronomical instruments. Moth-eye structure is a promising AR technique strong against cooling. The silicon lens and grism with the moth-eye structure are being developed to make high-throughput elements for long-wavelength mid-infrared instruments. A double-sided moth-eye plano-convex lens (Effective diameter: 33 mm, Focal length: 188 mm) was fabricated. By the transmittance measurement, it was confirmed that its total throughput is 1.7+/- 0.1 times higher than bare silicon lenses in a wide wavelength range of 20{45 μm. It suggests that the lens can achieve 83+/-5% throughput in the cryogenic temperature. It was also confirmed that the moth-eye processing on the lens does not modify the focal length. As for the grism, the homogeneous moth-eye processing on blaze pattern was realized by employing spray coating for the resist coating in EB lithography. The silicon grism with good surface roughness was also developed. The required techniques for completing moth-eye grisms have been established.

  2. Sol-gel-derived AR coatings for solar receivers

    NASA Astrophysics Data System (ADS)

    Ashley, C. S.; Reed, S. T.

    1984-09-01

    A process for applying sol-gel antireflection (AR) coatings to solar receiver envelopes is investigated. The process consists of applying a porous film which is subsequently etched to achieve the optimum AR effect. The result is a single-layer interference film with a reflectance minimum at 550 nm. The solar transmittance of coated tubes is typically increased to 0.05 to 0.97, as compared with 0.91 for uncoated tubes. Coated tubes showed no significant decrease in solar transmittance after 16 weeks of operation in a parabolic trough collector system. Recommendations are included for process improvement before industrial scale-up.

  3. Design and testing of AR coatings for MEGARA optics

    NASA Astrophysics Data System (ADS)

    Ortiz, R.; Carrasco, E.; Páez, G.; Pompa, O.; Sanchez-Blanco, E.; Gil de Paz, A.; Gallego, J.; Iglesias-Páramo, J.

    2016-08-01

    We present the antireflection coatings of the optical elements of MEGARA, the new integral field and multi-object spectrograph for the Gran Telescopio Canarias. We describe the methodology for optimizing the solutions. We also present the results of the final deposited coatings. The main optics require broadband coatings in the range from 370 nm to 980 nm for different materials with a mean R<1.3% at specific angles of incidence in each surface. For each material a specific arrangement of thicknesses of the same eight layers were produced and tested. For the spectrograph pupil elements four layer coatings were designed and produced R<0.3%. The design of main optics and pupil elements coatings have been shared between INAOE and CIO. The coating depositions have been performed at CIO in the Integrity 39 Denton Vacuum Deposition System. The main optics final coatings fulfill MEGARA requirements.

  4. Simple method for measuring reflectance of optical coatings

    SciTech Connect

    Wen Gui Wang; Yi Sheng Chen

    1995-12-31

    The quality of optical coatings has an important effect on the performance of optical instrument. The last few years, the requirements for super low loss dielectric mirror coatings used in low gain laser systems such as free electron laser and the ring laser etc., have given an impetus to the development of the technology of precise reflectance measurement of optical coatings. A reliable and workable technique is to measure the light intensity decay time of optical resonant cavity. This paper describes a measuring method which is dependent on direct measurement of the light intensity decay time of a resonant cavity comprised of low loss optical components. According to the evolution of a luminous flux stored inside the cavity, this method guarantees not only a quick and precise reflectance measurements of low loss highly reflecting mirror coatings but also transmittance measurements of low loss antireflection coatings and is especially effective with super los loss highly reflecting mirror. From the round-trip path length of the cavity and the speed of light, the light intensity exponential decay time of an optical cavity is easy to obtain and the cavity losses can be deduced. An optical reflectance of low loss highly mirror coatings and antireflection coatings is precisely measured as well. This is highly significant for the discrimination of the coating surface characteristics, the improvement of the performance of optical instrument and the development of high technology.

  5. Photochromic lens mirror-coated with Cr

    NASA Astrophysics Data System (ADS)

    Shin, Sungho; Lee, Myeongkyu

    2007-11-01

    We have designed and fabricated mirror-coated photochromic lenses for use in sunglasses. These lenses consisted of a Cr thin film sandwiched between two SiO2 layers on the front surface and an anti-reflection (AR) coating on the backside. The SiO2 films above and below the Cr layer were introduced as the protection and buffer layers, respectively. The AR coating was to suppress back-reflection from the lens surface. Deposition of all coating layers were carried out by an e-beam evaporator under Ar atmosphere at P = 10-5 Torr and T = 70 °C. As expected, the overall transmittance decreased with increasing Cr thickness. For a Cr layer of 5 nm thickness, it changed from about 45% in the bleached state down to 25% after exposure to sunlight. This is consistent with the transmission range typically required for sunglasses.

  6. Electrochemically synthesized broadband antireflective and hydrophobic GaOOH nanopillars for III-V InGaP/GaAs/Ge triple-junction solar cell applications.

    PubMed

    Leem, Jung Woo; Lee, Hee Kwan; Jun, Dong-Hwan; Heo, Jonggon; Park, Won-Kyu; Park, Jin-Hong; Yu, Jae Su

    2014-03-10

    We report the efficiency enhancement of III-V InGaP/GaAs/ Ge triple-junction (TJ) solar cells using a novel structure, i.e., vertically-oriented gallium oxide hydroxide (GaOOH) nanopillars (NPs), as an antireflection coating. The optical reflectance properties of rhombus-shaped GaOOH NPs, which were synthesized by a simple, low-cost, and large-scalable electrochemical deposition method, were investigated, together with a theoretical analysis using the rigorous coupled-wave analysis method. For the GaOOH NPs, the solar weighted reflectance of ~8.5% was obtained over a wide wavelength range of 300-1800 nm and their surfaces exhibited a high water contact angle of ~130° (i.e., hydrophobicity). To simply demonstrate the feasibility of device applications, the GaOOH NPs were incorporated into a test-grown InGaP/GaAs/Ge TJ solar cell structure. For the InGaP/GaAs/Ge TJ solar cell with broadband antireflective GaOOH NPs, the conversion efficiency (η) of ~16.47% was obtained, indicating an increased efficiency by 3.47% compared to the bare solar cell (i.e., η~13%).

  7. Rapid Mapping of AR Coating Thickness on Si Solar Cells Using GT-FabScan 6000

    SciTech Connect

    Sopori, B.; Amieva, J.; Butterfield, B.; Li, C.

    2005-02-01

    A new technique for rapid mapping of the thickness of an antireflection (AR) coating on a solar cell is described. A filtered, reflectance (intensity) image of the AR-coated wafer is generated by a CCD camera mounted on a GTFabScan. This image is converted into a thickness image using a transformation relating local AR thickness to the local intensity in the image plane. The thickness map is generated in <100 ms.

  8. Apparatus and method of manufacture for depositing a composite anti-reflection layer on a silicon surface

    NASA Technical Reports Server (NTRS)

    Pain, Bedabrata (Inventor)

    2012-01-01

    An apparatus and associated method are provided. A first silicon layer having at least one of an associated passivation layer and barrier is included. Also included is a composite anti-reflection layer including a stack of layers each with a different thickness and refractive index. Such composite anti-reflection layer is disposed adjacent to the first silicon layer.

  9. Angle dependent antireflection property of TiO2 inspired by cicada wings

    NASA Astrophysics Data System (ADS)

    Zada, Imran; Zhang, Wang; Li, Yao; Sun, Peng; Cai, Nianjin; Gu, Jiajun; Liu, Qinglei; Su, Huilan; Zhang, Di

    2016-10-01

    Inspired by cicada wings, biomorphic TiO2 with antireflective structures (ARSs) was precisely fabricated using a simple, inexpensive, and highly effective sol-gel process combined with subsequent calcination. It was confirmed that the fabricated biomorphic TiO2 not only effectively inherited the ARS but also exhibited high-performance angle dependent antireflective properties ranging from normal to 45°. Reflectance spectra demonstrated that the reflectivity of the biomorphic TiO2 with ARSs gradually changed from 1.4% to 7.8% with the increasing incidence angle over a large visible wavelength range. This angle dependent antireflective property is attributed to an optimized gradient refractive index between air and TiO2 via ARSs on the surface. Such surfaces with ARSs may have potential application in solar cells.

  10. Wideband antireflective circular polarizer exhibiting a perfect dark state in organic light-emitting-diode display.

    PubMed

    Kim, Bong Choon; Lim, Young Jin; Song, Je Hoon; Lee, Jun Hee; Jeong, Kwang-Un; Lee, Joong Hee; Lee, Gi-Dong; Lee, Seung Hee

    2014-12-15

    We proposed wideband antireflective circular polarizer for realizing a true black state in all viewing directions in organic light-emitting-diode displays (OLEDs). Present commercialized wideband circular polarizer consisted of a half wave and a quarter wave plates having the refractive index parameter (Nz) of 1.5 in both films exhibits light leakage in the oblique viewing directions, deteriorating image quality of a black state. We evaluated Nzs of both films and proposed a new wideband antireflective circular polarizer with a perfect dark state in all viewing directions with Nz = 0.5 in both plates, which will greatly improve image quality of OLEDs.

  11. Advanced antireflective nanostructures etched down from nanosilver colloid-transformed island mask

    NASA Astrophysics Data System (ADS)

    Park, Seong-Je; Kim, Chul-Hyun; Lee, Ji-Hye; Jeong, Jun-Ho; Lee, Eung-Sug; Choi, Jun-Hyuk

    2012-11-01

    Advanced fabrication methods for antireflective nanostructures are presented via the formation of thermally grown nanosilver islands from continuously deposited colloidal multilayers, followed by a multi-step reactive ion etch (RIE) with optimized gas mixture rate. This process allows the formation of a random array of nanostructures of diameter 150 nm or less and height greater than 200 nm. The reflectance falls to around 0.7% in the visible region, with reasonably enhanced broadband stability and reduced incidence angle dependence. The tunability of antireflection was investigated with respect to several parameters associated with the nanosilver etch mask fabrication and RIE conditions.

  12. A comparison of scattering and non-scattering anti-reflection designs for back contacted polycrystalline thin film silicon solar cells in superstrate configuration

    NASA Astrophysics Data System (ADS)

    Lockau, Daniel; Hammerschmidt, M.; Haschke, Jan; Blome, Mark; Ruske, F.; Schmidt, F.; Rech, B.

    2014-05-01

    A new generation of polycrystalline silicon thin film solar cells is currently being developed in laboratories, employing a combination of novel laser or electron beam based liquid phase crystallization (LPC) techniques and single side contacting systems. The lateral grain size of these polycrystalline cells is in the millimeter range at an absorber thickness of up to 10 μm. In this contribution we present a comparative simulation study of several 1D, 2D and 3D nano-optical designs for the substrate / illumination side interface to the several micrometer thick back contacted LPC silicon absorber material. The compared geometries comprise multilayer coatings, gratings with step and continuous profiles as well as combinations thereof. Using the transfer matrix method and a finite element method implementation to rigorously solve Maxwell's equations, we discuss anti-reflection and scattering properties of the different front interface designs in view of the angular distribution of incident light.

  13. Manufacturing and coating of optical components for the EnMAP hyperspectral imager

    NASA Astrophysics Data System (ADS)

    Schürmann, M.; Gäbler, D.; Schlegel, R.; Schwinde, S.; Peschel, T.; Damm, C.; Jende, R.; Kinast, J.; Müller, S.; Beier, M.; Risse, S.; Sang, B.; Glier, M.; Bittner, H.; Erhard, M.

    2016-07-01

    The optical system of the hyperspectral imager of the Environmental Mapping and Analysis Program (EnMAP) consists of a three-mirror anastigmat (TMA) and two independent spectrometers working in the VNIR and SWIR spectral range, respectively. The VNIR spectrometer includes a spherical NiP coated Al6061 mirror that has been ultra-precisely diamond turned and finally coated with protected silver as well as four curved fused silica (FS) and flint glass (SF6) prisms, respectively, each with broadband antireflection (AR) coating, while the backs of the two outer prisms are coated with a high-reflective coating. For AR coating, plasma ion assisted deposition (PIAD) has been used; the high-reflective enhanced Ag-coating on the backside has been deposited by magnetron sputtering. The SWIR spectrometer contains four plane and spherical gold-coated mirrors, respectively, and two curved FS prisms with a broadband antireflection coating. Details about the ultra-precise manufacturing of metal mirrors and prisms as well as their coating are presented in this work.

  14. Protective antireflection coatings for optical IR fibers based on silver halogenides

    NASA Astrophysics Data System (ADS)

    Glebov, V. N.; Leonov, Pavel G.; Malyutin, A. M.; Yakunin, Vladimir P.

    2002-04-01

    The polycrystalline optical IR fibers based on silver halogenides AgCl-AgBr exhibiting low losses (0.5 dB/m and less) in the wavelength range from 4.0 to 16.0 micrometers are of interest in technical and medico-biological applications as fiber optic sensing devices and flexible systems for delivery of low-power CO2 and CO lasers radiation.

  15. Hollow carbon spheres in microwaves: Bio inspired absorbing coating

    NASA Astrophysics Data System (ADS)

    Bychanok, D.; Li, S.; Sanchez-Sanchez, A.; Gorokhov, G.; Kuzhir, P.; Ogrin, F. Y.; Pasc, A.; Ballweg, T.; Mandel, K.; Szczurek, A.; Fierro, V.; Celzard, A.

    2016-01-01

    The electromagnetic response of a heterostructure based on a monolayer of hollow glassy carbon spheres packed in 2D was experimentally surveyed with respect to its response to microwaves, namely, the Ka-band (26-37 GHz) frequency range. Such an ordered monolayer of spheres mimics the well-known "moth-eye"-like coating structures, which are widely used for designing anti-reflective surfaces, and was modelled with the long-wave approximation. Based on the experimental and modelling results, we demonstrate that carbon hollow spheres may be used for building an extremely lightweight, almost perfectly absorbing, coating for Ka-band applications.

  16. Silicon Nanostructures Produced by Modified MacEtch Method for Antireflective Si Surface.

    PubMed

    Nichkalo, Stepan; Druzhinin, Anatoly; Evtukh, Anatoliy; Bratus', Oleg; Steblova, Olga

    2017-12-01

    This work pertains to the method for modification of silicon (Si) wafer morphology by metal-assisted chemical etching (MacEtch) technique suitable for fabrication of antireflective Si surfaces. For this purpose, we made different Au catalyst patterns on the surface of Si substrate. This modification allowed to obtain the close-packed Au nanodrop (ND) pattern that generates the nanowires (NWs) and the well-separated Au NDs, which induce the nanopore (NP) formation. The antireflective properties of these structures in comparison with NWs produced by the conventional Ag-MacEtch method were analysed. The total surface reflectance of 1~7% for SiNWs and ~17% for SiNPs was observed over the entire Si-absorbing region. Moreover, SiNWs prepared by Au-MacEtch demonstrate better antireflective properties in contrast to those formed by conventional Ag-assisted chemical etching. So, the use of SiNWs produced by the modified Au-MacEtch method as the antireflective material is favored over those prepared by Ag-MacEtch due to their higher light absorption and lower reflectance. The possible reason of these findings is discussed.

  17. Silicon Nanostructures Produced by Modified MacEtch Method for Antireflective Si Surface

    NASA Astrophysics Data System (ADS)

    Nichkalo, Stepan; Druzhinin, Anatoly; Evtukh, Anatoliy; Bratus', Oleg; Steblova, Olga

    2017-02-01

    This work pertains to the method for modification of silicon (Si) wafer morphology by metal-assisted chemical etching (MacEtch) technique suitable for fabrication of antireflective Si surfaces. For this purpose, we made different Au catalyst patterns on the surface of Si substrate. This modification allowed to obtain the close-packed Au nanodrop (ND) pattern that generates the nanowires (NWs) and the well-separated Au NDs, which induce the nanopore (NP) formation. The antireflective properties of these structures in comparison with NWs produced by the conventional Ag-MacEtch method were analysed. The total surface reflectance of 1 7% for SiNWs and 17% for SiNPs was observed over the entire Si-absorbing region. Moreover, SiNWs prepared by Au-MacEtch demonstrate better antireflective properties in contrast to those formed by conventional Ag-assisted chemical etching. So, the use of SiNWs produced by the modified Au-MacEtch method as the antireflective material is favored over those prepared by Ag-MacEtch due to their higher light absorption and lower reflectance. The possible reason of these findings is discussed.

  18. Use of antireflection layers to avoid ghost plating on Ni/Cu plated crystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    Jeong, Myeong Sang; Choi, Sung Jin; Chang, Hyo Sik; In Lee, Jeong; Kang, Min Gu; Kim, Donghwan; Song, Hee-eun

    2016-03-01

    Screen printing is a method commonly used for making electrodes for crystalline silicon solar cells. Although the screen-printing method is fast and easy, screen-printed electrodes have a porous structure, high contact resistance, and low aspect ratio. On the other hand, plated electrodes have low contact resistance and narrow electrode width. Therefore, the plating method could be substituted for the screen-printing method in crystalline silicon solar cells. During the plating process, ghost plating can appear at the surface when the quality of the passivation layer is poor, causing an increase in the recombination rate. In this paper, light-induced plating was applied to the fabrication of electrodes, and various passivation layers were investigated to remove ghost plating in crystalline silicon solar cells. These included, (1) SiNx deposited by plasma-enhanced chemical vapor deposition (PECVD), (2) a double SiNx layer formed by PECVD, (3) a double layer with thermal silicon oxide and SiNx deposited by PECVD, and (4) a double layer comprising SiNx and SiOx formed by PECVD. For the plated solar cells, a laser was used to remove various antireflection coating (ARC) layers and phosphoric acid was spin-coated onto the doped silicon wafer prior to laser ablation. Also, a screen-printed solar cell was fabricated to compare plated solar cells with screen-printed solar cells. As a result, we found that a thermal SiO2/PECVD SiNx layer showed the lowest pinhole density and its wet vapor transmission rate was characterized. The solar cell with the thermal SiO2/PECVD SiNx layer showed the lowest J02 value, as well as improved Voc and Jsc.

  19. Evaluation of glass resin coatings for solar cell applications

    NASA Technical Reports Server (NTRS)

    Field, M. B.

    1978-01-01

    Using a variety of non-vacuum deposition techniques coatings were implemented on silicon solar cells and arrays of cells interconnected on Kapton substrates. The coatings provide both antireflection optical matching and environmental protection. Reflectance minima near 2% was achieved at a single wavelength in the visible. Reflectance averaging below 5% across the useful collection range was demonstrated. The coatings and methods of deposition were: (1) Ta2O5 spun, dipped or sprayed; (2) Ta2O5.SiO2 spun, dipped or sprayed; (3) GR908 (SiO2) spun, dipped, or sprayed. Total coating thickness were in the range of 18 microns to 25 microns. The coatings and processes are compatible with single cells or cells mounted on Kapton substrates.

  20. Self-assembled nanolaminate coatings (SV)

    SciTech Connect

    Fan, H.

    2012-03-01

    Sandia National Laboratories (Sandia) and Lockheed Martin Aeronautics (LM Aero) are collaborating to develop affordable, self-assembled, nanocomposite coatings and associated fabrication processes that will be tailored to Lockheed Martin product requirements. The purpose of this project is to develop a family of self-assembled coatings with properties tailored to specific performance requirements, such as antireflective (AR) optics, using Sandia-developed self-assembled techniques. The project met its objectives by development of a simple and economic self-assembly processes to fabricate multifunctional coatings. Specifically, materials, functionalization methods, and associated coating processes for single layer and multiple layers coatings have been developed to accomplish high reflective coatings, hydrophobic coatings, and anti-reflective coatings. Associated modeling and simulations have been developed to guide the coating designs for optimum optical performance. The accomplishments result in significant advantages of reduced costs, increased manufacturing freedom/producibility, improved logistics, and the incorporation of new technology solutions not possible with conventional technologies. These self-assembled coatings with tailored properties will significantly address LMC's needs and give LMC a significant competitive lead in new engineered materials. This work complements SNL's LDRD and BES programs aimed at developing multifunctional nanomaterials for microelectronics and optics as well as structure/property investigations of self-assembled nanomaterials. In addition, this project will provide SNL with new opportunities to develop and apply self-assembled nanocomposite optical coatings for use in the wavelength ranges of 3-5 and 8-12 micrometers, ranges of vital importance to military-based sensors and weapons. The SANC technologies will be applied to multiple programs within the LM Company including the F-35, F-22, ADP (Future Strike Bomber, UAV, UCAV

  1. Improvement and characterization of high-reflective and anti-reflective nanostructured mirrors by ion beam assisted deposition for 944 nm high power diode laser

    NASA Astrophysics Data System (ADS)

    Ghadimi-Mahani, A.; Farsad, E.; Goodarzi, A.; Tahamtan, S.; Abbasi, S. P.; Zabihi, M. S.

    2015-11-01

    Single-layer and multi-layer coatings were applied on the surface of diode laser facets as mirrors. This thin film mirrors were designed, deposited, optimized and characterized. The effects of mirrors on facet passivation and optical properties of InGaAs/AlGaAs/GaAs diode lasers were investigated. High-Reflective (HR) and Anti-Reflective (AR) mirrors comprising of four double-layers of Al2O3/Si and a single layer of Al2O3, respectively, were designed and optimized by Macleod software for 944 nm diode lasers. Optimization of Argon flow rate was studied through Alumina thin film deposition by Ion Beam Assisted Deposition (IBAD) for mirror improvement. The nanostructured HR and AR mirrors were deposited on the front and back facet of the laser respectively, by IBAD system under optimum condition. Atomic Force Microscope (AFM), Vis-IR Spectrophotometer, Field Emission Scanning Electron Microscopy (FESEM) and laser characterization Test (P-I) were used to characterize various properties of mirrors and lasers. AFM images show mirror's root mean square roughness is nearly 1 nm. The Spectrophotometer results of the front facet transmission and the back facet reflection are in good agreement with the simulation results. Optical output power (P) versus driving current (I) characteristics, measured before and after coating the facet, revealed a significant output power enhancement due to optimized AR and HR optical coatings on facets.

  2. Sol-gel optical coatings for lasers, 2

    SciTech Connect

    Floch, H.G.; Belleville, P.F.; Priotton, J.J.; Pegon, P.M.; Dijonneau, C.S.; Guerain, J.

    1995-11-01

    There are three basic types of antireflective (AR) coatings. The first is a single-layer coating in which the coating index is equal to the square root of the index of the substrate, assuming air is the external medium. The second type is a system of two or more layers of different indexes. The third type is a graded-index system, where the index is uniformly and continuously graded from the substrate to the external medium. Low reflection ranges from narrow for the single-layer to broad for the graded-layer and multilayered with a large number of layers. Four types of sol-gel AR coatings have been developed at CEL-V. They are based on single-layer or multilayer designs. They consist mainly of amorphous silica in the polymeric and/or colloidal state, combined in certain cases with other metallic oxides, binders, fillers, hydrophobic and lubricating agents, and adhesion promoters. These antireflective sol-gel-derived optical coatings have been prepared and tested for the proposed French megajoule neodymium-glass laser.

  3. Custom beamsplitter and AR coatings for interferometry

    NASA Astrophysics Data System (ADS)

    Nyland, K.; Jurgenson, C. A.; Buscher, D. F.; Haniff, C. A.; Young, J. S.; Lewis, J.; Schnell, R.

    2010-07-01

    We report on final fabrication tests for the dielectric coatings for the Magdalena Ridge Observatory Interferometer (MROI) fringe tracking beam combiner. The broadband anti-reflection (1.1 μm to 2.4 μm) and beamsplitter (1.49 μm to 2.31 μm) coatings required have been designed with both optical and mechanical constraints in mind. Not only do these coatings have very low optical losses, but they induce minimal bending of their substrates, thereby giving very low fringe contrast reductions. Performance tests on the deposited coatings at our manufacturers (Optical Surface Technologies, Albuquerque, NM) demonstrate reflection losses of less than 0.5% over the full bandpass of the AR coating, and deviations from the desired 50:50 intensity ratio of the beamsplitter coating of no more than 2%. When combined with the measured wavefront perturbations these results imply that the total fringe visibility losses induced by imperfect coating quality will be no more than 2% for all outputs of the MROI fringe tracking beam combiner.

  4. Fabrication of broadband antireflective black metal surfaces with ultra-light-trapping structures by picosecond laser texturing and chemical fluorination

    NASA Astrophysics Data System (ADS)

    Zheng, Buxiang; Wang, Wenjun; Jiang, Gedong; Mei, Xuesong

    2016-06-01

    A hybrid method consisting of ultrafast laser-assisted texturing and chemical fluorination treatment was applied for efficiently enhancing the surface broadband antireflection to fabricate black titanium alloy surface with ultra-light-trapping micro-nanostructure. Based on the theoretical analysis of surface antireflective principle of micro-nanostructures and fluoride film, the ultra-light-trapping micro-nanostructures have been processed using a picosecond pulsed ultrafast laser on titanium alloy surfaces. Then fluorination treatment has been performed by using fluoroalkyl silane solution. According to X-ray diffraction phase analysis of the surface compositions and measurement of the surface reflectance using spectrophotometer, the broadband antireflective properties of titanium alloy surface with micro-nano structural characteristics were investigated before and after fluorination treatment. The results show that the surface morphology of micro-nanostructures processed by picosecond laser has significant effects on the antireflection of light waves to reduce the surface reflectance, which can be further reduced using chemical fluorination treatment. The high antireflection of over 98 % in a broad spectral range from ultraviolet to infrared on the surface of metal material has been achieved for the surface structures, and the broadband antireflective black metal surfaces with an extremely low reflectance of ultra-light-trapping structures have been obtained in the wavelength range from ultraviolet-visible to near-infrared, middle-wave infrared. The average reflectance of microgroove groups structured surface reaches as low as 2.43 % over a broad wavelength range from 200 to 2600 nm. It indicates that the hybrid method comprising of picosecond laser texturing and chemical fluorination can effectively induce the broadband antireflective black metal surface. This method has a potential application for fabricating antireflective surface used to improve the

  5. Study on structural and optical properties of TiO2 ALD coated silicon nanostructures

    NASA Astrophysics Data System (ADS)

    Pavlenko, Mykola; Myndrul, Valerii; Iatsunskyi, Igor; Jurga, Stefan; Smyntyna, Valentyn

    2016-04-01

    Structural and optical properties of TiO2 ALD coated silicon nanostructures were investigated. The morphology and chemical composition of TiO2 coated silicon nanopillars and porous silicon were studied by using methods of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Optical characteristics were studied using measurements of reflectance and luminescence spectra. Detailed analysis of morphological features and photoluminescence mechanisms were provided. Peculiarities of reflectance spectra were discussed. It was shown the possible application of these structures as antireflectance coatings.

  6. Investigation of the ageing effects exhibited by AR coatings exposed to ultraviolet laser irradiation

    NASA Astrophysics Data System (ADS)

    Botha, Roelene; Bischof, David; Vetsch, Bernhard; Scherrer, Ueli; Michler, Markus; Rinner, Stefan J.; Ettemeyer, Andreas; Ziolek, Carsten

    2016-12-01

    Optical coatings used in ultraviolet applications are often exposed to harsh environments operating at elevated temperatures. In order to study the impact of the ageing effects optical coatings experience at various operating temperatures, an ultraviolet laser-induced degradation test system has been developed. It allows for flexible use in both a long-term stability test bench as well as in an LIDT measurement system. This work contains the preliminary results of optical degradation tests at 355 nm performed on anti-reflective coatings. As a subsequent step, the LIDT of the samples were measured using a Q-Switched Nd:YAG laser operating at 1064nm.

  7. Solution-phase synthesis of single-crystal Cu3Si nanowire arrays on diverse substrates with dual functions as high-performance field emitters and efficient anti-reflective layers

    NASA Astrophysics Data System (ADS)

    Yuan, Fang-Wei; Wang, Chiu-Yen; Li, Guo-An; Chang, Shu-Hao; Chu, Li-Wei; Chen, Lih-Juann; Tuan, Hsing-Yu

    2013-09-01

    There is strong and growing interest in applying metal silicide nanowires as building blocks for a new class of silicide-based applications, including spintronics, nano-scale interconnects, thermoelectronics, and anti-reflective coating materials. Solution-phase environments provide versatile materials chemistry as well as significantly lower production costs compared to gas-phase synthesis. However, solution-phase synthesis of silicide nanowires remains challenging due to the lack of fundamental understanding of silicidation reactions. In this study, single-crystalline Cu3Si nanowire arrays were synthesized in an organic solvent. Self-catalyzed, dense single-crystalline Cu3Si nanowire arrays were synthesized by thermal decomposition of monophenylsilane in the presence of copper films or copper substrates at 420 to 475 °C and 10.3 MPa in supercritical benzene. The solution-grown Cu3Si nanowire arrays serve dual functions as field emitters and anti-reflective layers, which are reported on copper silicide materials for the first time. Cu3Si nanowires exhibit superior field-emission properties, with a turn-on-voltage as low as 1.16 V μm-1, an emission current density of 8 mA cm-2 at 4.9 V μm-1, and a field enhancement factor (β) of 1500. Cu3Si nanowire arrays appear black with optical absorption less than 5% between 400 and 800 nm with minimal reflectance, serving as highly efficient anti-reflective layers. Moreover, the Cu3Si nanowires could be grown on either rigid or flexible substrates (PI). This study shows that solution-phase silicide reactions are adaptable for high-quality silicide nanowire growth and demonstrates their promise towards fabrication of metal silicide-based devices.There is strong and growing interest in applying metal silicide nanowires as building blocks for a new class of silicide-based applications, including spintronics, nano-scale interconnects, thermoelectronics, and anti-reflective coating materials. Solution-phase environments

  8. 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.

  9. Antireflective surface with a step in the taper: Numerical optimization and large-area fabrication

    NASA Astrophysics Data System (ADS)

    Shinotsuka, Kei; Hongo, Koki; Dai, Kotaro; Hirama, Satoru; Hatta, Yoshihisa

    2017-02-01

    In this study, we developed a practical method to improve the optical performance of subwavelength antireflective two-dimensional (2D) gratings. A numerical simulation of both convex and concave paraboloids suggested that surface reflectivity drastically decreases when a step is introduced in the taper. The optimum height and depth of a step provided average reflectances of 0.098% for convex protrusions and 0.040% for concave protrusions in the visible range. Furthermore, a stepped paraboloid was experimentally fabricated by dry etching of a Si substrate with SiO2 particle monolayer mask. A cyclo-olefin polymer (COP) reverse replica (concave) imprinted by the Si mold exhibited a measured reflectance of 0.077% on average in the visible range. It was also demonstrated that the antireflective structure was fabricated on the whole surface of a 6 in. Si wafer, which is a sufficient size for industrial utilization.

  10. Fabrication of nano-structure anti-reflective lens using platinum nanoparticles in injection moulding

    NASA Astrophysics Data System (ADS)

    Kurihara, K.; Saitou, Y.; Souma, N.; Makihara, S.; Kato, H.; Nakano, T.

    2015-01-01

    We provide a lens mould to attain an anti-reflection sub-wavelength structure (SWS) for plastic replica in the injection moulding process. To obtain the SWS on the lens mould, platinum nanoparticles formed by decomposition of a platinum oxide were employed. The fabricated platinum nanoparticles were estimated to be 90 nm in diameter, on average, and the dispersion of the particle diameter was evaluated to be ±20 nm. Through nanostructure replication by injection moulding, antireflection of less than 0.5% was achieved, and transmittance increased over 98%. In addition, a high-replication durability of over 10 000 times was attained. The variation of the minimum reflection ratio was evaluated to be 0.38% ± 0.04%. The usefulness of the proposed SWS mould for mass-production was confirmed, as it allows for high durability and SWS formation on the lens surface.

  11. Enhanced antireflecting properties of micro-structured top-flat pyramids.

    PubMed

    Bouffaron, R; Escoubas, L; Simon, J J; Torchio, Ph; Flory, F; Berginc, G; Masclet, Ph

    2008-11-10

    This paper aims at modeling bi-periodic micro-structured silicon surfaces exhibiting broadband antireflection properties in the infrared range using Rigorous Coupled-Wave Analysis (RCWA). These structures of pyramidal shape, which typical dimensions are smaller than the wavelength, are not in the Effective Medium Theory (EMT) validity domain. The influence of various opto-geometrical parameters such as period, depth, shape of the pattern is examined. The antireflective properties of such bi-periodic patterned surfaces are then discussed using the photonic crystal theory and photonic band diagrams description. Correlations between the density of Bloch modes, their localizations with respect to the incident medium light line and the surface reflectance are presented.

  12. Solution-phase synthesis of single-crystal Cu3Si nanowire arrays on diverse substrates with dual functions as high-performance field emitters and efficient anti-reflective layers.

    PubMed

    Yuan, Fang-Wei; Wang, Chiu-Yen; Li, Guo-An; Chang, Shu-Hao; Chu, Li-Wei; Chen, Lih-Juann; Tuan, Hsing-Yu

    2013-10-21

    There is strong and growing interest in applying metal silicide nanowires as building blocks for a new class of silicide-based applications, including spintronics, nano-scale interconnects, thermoelectronics, and anti-reflective coating materials. Solution-phase environments provide versatile materials chemistry as well as significantly lower production costs compared to gas-phase synthesis. However, solution-phase synthesis of silicide nanowires remains challenging due to the lack of fundamental understanding of silicidation reactions. In this study, single-crystalline Cu3Si nanowire arrays were synthesized in an organic solvent. Self-catalyzed, dense single-crystalline Cu3Si nanowire arrays were synthesized by thermal decomposition of monophenylsilane in the presence of copper films or copper substrates at 420 to 475 °C and 10.3 MPa in supercritical benzene. The solution-grown Cu3Si nanowire arrays serve dual functions as field emitters and anti-reflective layers, which are reported on copper silicide materials for the first time. Cu3Si nanowires exhibit superior field-emission properties, with a turn-on-voltage as low as 1.16 V μm(-1), an emission current density of 8 mA cm(-2) at 4.9 V μm(-1), and a field enhancement factor (β) of 1500. Cu3Si nanowire arrays appear black with optical absorption less than 5% between 400 and 800 nm with minimal reflectance, serving as highly efficient anti-reflective layers. Moreover, the Cu3Si nanowires could be grown on either rigid or flexible substrates (PI). This study shows that solution-phase silicide reactions are adaptable for high-quality silicide nanowire growth and demonstrates their promise towards fabrication of metal silicide-based devices.

  13. Transparent conductive coatings

    NASA Technical Reports Server (NTRS)

    Ashok, S.

    1983-01-01

    Thin film transparent conductors are discussed. Materials with electrical conductivity and optical transparency are highly desirable in many optoelectronic applications including photovoltaics. Certain binary oxide semiconductors such as tin oxide (SnO2) and indium oxide (In2O3) offer much better performance tradeoff in optoelectronics as well as better mechanical and chemical stability than thin semitransparent films. These thin-film transparent conductors (TC) are essentially wide-bandgap degenerate semiconductors - invariably n-type - and hence are transparent to sub-bandgap (visible) radiation while affording high electrical conductivity due to the large free electron concentration. The principal performance characteristics of TC's are, of course, electrical conductivity and optical transmission. The TC's have a refractive index of around 2.0 and hence act as very efficient antireflection coatings. For using TC's in surface barrier solar cells, the photovoltaic barrier is of utmost importance and so the work function or electron affinity of the TC is also a very important material parameter. Fabrication processes are discussed.

  14. Improved broadband and quasi-omnidirectional anti-reflection properties with biomimetic silicon nanostructures

    NASA Astrophysics Data System (ADS)

    Huang, Yi-Fan; Chattopadhyay, Surojit; Jen, Yi-Jun; Peng, Cheng-Yu; Liu, Tze-An; Hsu, Yu-Kuei; Pan, Ci-Ling; Lo, Hung-Chun; Hsu, Chih-Hsun; Chang, Yuan-Huei; Lee, Chih-Shan; Chen, Kuei-Hsien; Chen, Li-Chyong

    2007-12-01

    Nature routinely produces nanostructured surfaces with useful properties, such as the self-cleaning lotus leaf, the colour of the butterfly wing, the photoreceptor in brittlestar and the anti-reflection observed in the moth eye. Scientists and engineers have been able to mimic some of these natural structures in the laboratory and in real-world applications. Here, we report a simple aperiodic array of silicon nanotips on a 6-inch wafer with a sub-wavelength structure that can suppress the reflection of light at a range of wavelengths from the ultraviolet, through the visible part of the spectrum, to the terahertz region. Reflection is suppressed for a wide range of angles of incidence and for both s- and p-polarized light. The antireflection properties of the silicon result from changes in the refractive index caused by variations in the height of the silicon nanotips, and can be simulated with models that have been used to explain the low reflection from moth eyes. The improved anti-reflection properties of the surfaces could have applications in renewable energy and electro-optical devices for the military.

  15. Broadband High-Performance Infrared Antireflection Nanowires Facilely Grown on Ultrafast Laser Structured Cu Surface.

    PubMed

    Fan, Peixun; Bai, Benfeng; Long, Jiangyou; Jiang, Dafa; Jin, Guofan; Zhang, Hongjun; Zhong, Minlin

    2015-09-09

    Infrared antireflection is an essential issue in many fields such as thermal imaging, sensors, thermoelectrics, and stealth. However, a limited antireflection capability, narrow effective band, and complexity as well as high cost in implementation represent the main unconquered problems, especially on metal surfaces. By introducing precursor micro/nano structures via ultrafast laser beforehand, we present a novel approach for facile and uniform growth of high-quality oxide semiconductor nanowires on a Cu surface via thermal oxidation. Through the enhanced optical phonon dissipation of the nanowires, assisted by light trapping in the micro structures, ultralow total reflectance of 0.6% is achieved at the infrared wavelength around 17 μm and keeps steadily below 3% over a broad band of 14-18 μm. The precursor structures and the nanowires can be flexibly tuned by controlling the laser processing procedure to achieve desired antireflection performance. The presented approach possesses the advantages of material simplicity, structure reconfigurability, and cost-effectiveness for mass production. It opens a new path to realize unique functions by integrating semiconductor nanowires onto metal surface structures.

  16. Nanoporosity-induced superhydrophobicity and large antireflection in InSb

    NASA Astrophysics Data System (ADS)

    Datta, Debi Prasad; Som, Tapobrata

    2016-05-01

    A porous nanostructure evolves in InSb due to keV ion implantation which leads to superhydrophobic and large antireflective property, indicating a single-step facile fabrication to introduce both functionalities. In particular, it is observed that the contact angle of a water droplet on the nanoporous InSb surface exceeds 150°, revealing the transition to a superhydrophobic surface. Correlation between the contact angle and the porous nanostructures is qualitatively understood in light of the Cassie-Baxter model. It is found that a decrease in the fraction of solid surface wetted by the water droplet and a corresponding increase in the air-water interface fraction lead to the enhancement in the hydrophobicity. We further observe that the large broadband antireflection (in the range of 200-800 nm) is also correlated to the nanoporous structure, arising out of a large reduction in the refractive index due to its increasing porosity. Such a surface with the combination of superhydrophobicity and large antireflection can be very useful for applications of InSb nanostructures in electronic, photonic devices, or infrared detectors.

  17. UV-black rutile TiO{sub 2}: An antireflective photocatalytic nanostructure

    SciTech Connect

    Sanz, Ruy Zimbone, Massimo; Buccheri, Maria Antonietta; Scuderi, Viviana; Impellizzeri, Giuliana; Privitera, Vittorio; Romano, Lucia; Scuderi, Mario; Nicotra, Giuseppe; Jensen, Jens

    2015-02-21

    This work presents an experimental study on the specific quantitative contributions of antireflective and effective surface areas on the photocatalytic and antibacterial properties of rutile TiO{sub 2} nanospikes. They are studied when continuously distributed over the whole surface and when integrated into well-defined microstructures. The nanospikes were produced following MeV ion beam irradiation of bulk rutile TiO{sub 2} single crystals and subsequent chemical etching. The ion beam irradiation generated embedded isolated crystalline nanoparticles inside an etchable amorphous TiO{sub 2} layer, and nanospikes fixed to the not etchable TiO{sub 2} bulk substrate. The produced nanospikes are shown to resist towards aggressive chemical environments and act as an efficient UV antireflective surface. The photocatalytic activity experiments were performed under the ISO 10678:2010 protocol. The photonic and quantum efficiency are reported for the studied samples. The combined micro- and nanostructured surface triples the photonic efficiency compared to the initial flat surface. Results also revealed that the antireflective effect, due to the nanostructuring, is the dominating factor compared to the increase of surface area, for the observed photocatalytic response. The obtained results may be taken as a general strategy to design and precisely evaluate photoactive nanostructures.

  18. Both antireflection and superhydrophobicity structures achieved by direct laser interference nanomanufacturing

    NASA Astrophysics Data System (ADS)

    Wang, Dapeng; Wang, Zuobin; Zhang, Ziang; Yue, Yong; Li, Dayou; Qiu, Renxi; Maple, Carsten

    2014-06-01

    Inspired by nature, a number of techniques have been developed to fabricate the bionic structures of lotus leaves and moth eyes in order to realize the extraordinary functions of self-cleaning and antireflection. Compared with the existing technologies, we present a straightforward method to fabricate well-defined micro and nano artificial bio-structures in this work. The proposed method of direct laser interference nanomanufacturing (DLIN) takes a significant advantage of high efficiency as only a single technological procedure is needed without pretreatment, mask, and pattern transfer processes. Meanwhile, the corresponding structures show both antireflection and superhydrophobicity properties simultaneously. The developed four-beam nanosecond laser interference system configuring the TE-TE-TE-TE and TE-TE-TE-TM polarization modes was set up to generate periodic micro cone and hole structures with a huge number of nano features on the surface. The theoretical and experimental results have shown that the periodic microcone structure exhibits excellent properties with both a high contact angle (CA = 156.3°) and low omnidirectional reflectance (5.9-15.4%). Thus, DLIN is a novel and promising method suitable for mass production of self-cleaning and antireflection surface structures.

  19. Both antireflection and superhydrophobicity structures achieved by direct laser interference nanomanufacturing

    SciTech Connect

    Wang, Dapeng; Wang, Zuobin Maple, Carsten; Zhang, Ziang; Yue, Yong; Li, Dayou; Qiu, Renxi

    2014-06-21

    Inspired by nature, a number of techniques have been developed to fabricate the bionic structures of lotus leaves and moth eyes in order to realize the extraordinary functions of self-cleaning and antireflection. Compared with the existing technologies, we present a straightforward method to fabricate well-defined micro and nano artificial bio-structures in this work. The proposed method of direct laser interference nanomanufacturing (DLIN) takes a significant advantage of high efficiency as only a single technological procedure is needed without pretreatment, mask, and pattern transfer processes. Meanwhile, the corresponding structures show both antireflection and superhydrophobicity properties simultaneously. The developed four-beam nanosecond laser interference system configuring the TE-TE-TE-TE and TE-TE-TE-TM polarization modes was set up to generate periodic micro cone and hole structures with a huge number of nano features on the surface. The theoretical and experimental results have shown that the periodic microcone structure exhibits excellent properties with both a high contact angle (CA = 156.3°) and low omnidirectional reflectance (5.9–15.4%). Thus, DLIN is a novel and promising method suitable for mass production of self-cleaning and antireflection surface structures.

  20. Design principles for morphologies of antireflection patterns for solar absorbing applications.

    PubMed

    Moon, Yoon-Jong; Na, Jin-Young; Kim, Sun-Kyung

    2015-07-01

    Two-dimensional surface texturing is a widespread technology for imparting broadband antireflection, yet its design rules are not completely understood. The dependence of the reflectance spectrum of a periodically patterned glass film on various structural parameters (e.g., pitch, height, shape, and fill factor) has been investigated by means of full-vectorial numerical simulations. An average weighted reflectivity accounting for the AM1.5G solar spectrum (λ=300-1000  nm) was sinusoidally modulated by a rod pattern's height, and was minimized for pitches of 400-600 nm. When a rationally optimized cone pattern was used, the average weighted reflectivity was less than 0.5%, for incident angles of up to 40° off normal. The broadband antireflection of a cone pattern was reproduced well by a graded refractive index film model corresponding to its geometry, with the addition of a diffraction effect resulting from its periodicity. The broadband antireflection ability of optimized cone patterns is not limited to the glass material, but rather is generically applicable to other semiconductor materials, including Si and GaAs. The design rules developed herein represent a key step in the development of light-absorbing devices, such as solar cells.

  1. Demonstration of Resonance Coupling in Scalable Dielectric Microresonator Coatings for Photovoltaics.

    PubMed

    Ha, Dongheon; Gong, Chen; Leite, Marina S; Munday, Jeremy N

    2016-09-21

    To increase the power conversion efficiency of solar cells, improved antireflection coatings are needed to couple light into the cell with minimal parasitic loss. Here, we present measurements and simulations of an antireflection coating based on silicon dioxide (SiO2) nanospheres that improve solar cell absorption by coupling light from free space into the absorbing layer through excitation of modes within the nanospheres. The deposited monolayer of nanospheres leads to a significant increase in light absorption within an underlying semiconductor on the order of 15-20%. When the periodicity and spacing between the nanospheres are varied, whispering gallery-like modes can be excited and tuned throughout the visible spectrum. The coating was applied to a Si solar cell containing a Si3N4 antireflection layer, and an additional increase in the spectral current density of ∼5% was found. The fabrication process, involving Meyer rod rolling, is scalable and inexpensive and could enable large-scale manufacturability of microresonator-based photovoltaics.

  2. Imprinted moth-eye antireflection patterns on glass substrate

    NASA Astrophysics Data System (ADS)

    Hong, Sung-Hoon; Bae, Byeong-Ju; Han, Kang-Soo; Hong, Eun-Ju; Lee, Heon; Choi, Kyung-Woo

    2009-03-01

    Sub-micron sized, conical shaped moth-eye structure was transferred to thermoplastic polymer film, such as polyvinyl chloride (PVC) using hot embossing process. Since master template was made of polycarbonate, embossing temperature and pressure were carefully maintained to 100°C and 10 atm. Conical shaped moth-eye pattern was reversed to tapered hole pattern on PVC film. Hot embossed PVC film was then used as transparent template for subsequent UV nanoimprint process, in order to form the conical shaped sub-micron moth-eye structure on glass substrate. After thin layer of Si oxide and monolayer of self-assembled, silane based molecules was coated on hot embossed PVC film. UV nanoimprint process was done on the glass substrate using hot embossed PVC film. As a result, the transmittance of glass substrate was increased from 91 to 94% for single side patterned and 96% for both side patterned glass substrate for the spectral range of 350 to 800 nm.

  3. High temperature solar selective coatings

    DOEpatents

    Kennedy, Cheryl E

    2014-11-25

    Improved solar collectors (40) comprising glass tubing (42) attached to bellows (44) by airtight seals (56) enclose solar absorber tubes (50) inside an annular evacuated space (54. The exterior surfaces of the solar absorber tubes (50) are coated with improved solar selective coatings {48} which provide higher absorbance, lower emittance and resistance to atmospheric oxidation at elevated temperatures. The coatings are multilayered structures comprising solar absorbent layers (26) applied to the meta surface of the absorber tubes (50), typically stainless steel, topped with antireflective Savers (28) comprising at least two layers 30, 32) of refractory metal or metalloid oxides (such as titania and silica) with substantially differing indices of refraction in adjacent layers. Optionally, at least one layer of a noble metal such as platinum can be included between some of the layers. The absorbent layers cars include cermet materials comprising particles of metal compounds is a matrix, which can contain oxides of refractory metals or metalloids such as silicon. Reflective layers within the coating layers can comprise refractory metal silicides and related compounds characterized by the formulas TiSi. Ti.sub.3SiC.sub.2, TiAlSi, TiAN and similar compounds for Zr and Hf. The titania can be characterized by the formulas TiO.sub.2, Ti.sub.3O.sub.5. TiOx or TiO.sub.xN.sub.1-x with x 0 to 1. The silica can be at least one of SiO.sub.2, SiO.sub.2x or SiO.sub.2xN.sub.1-x with x=0 to 1.

  4. Antireflection treatment of thickness sensitive spectrally selective (TSSS) paints for thermal solar absorbers

    SciTech Connect

    Lundh, M.; Waeckelgaard, E.; Blom, T.

    2010-01-15

    There are several methods to produce solar absorbers, and one cheap alternative is painted absorbers, preferably painted with a spectrally selective paint. The optical properties of Thickness Sensitive Spectrally Selective (TSSS) paints are, however, limited by the thickness of the paint layer. In this study it is shown that the solar absorptance of two commercial TSSS paints can be increased between 0.01 and 0.02 units with an antireflection treatment using a silicon dioxide layer deposited from silica-gel. It was found that the thermal emittance (100 C) did not change significantly after the treatment. (author)

  5. Synthesis of Si/SiO2 core-shell nanowire arrays and broadband anti-reflection effects in diluted Si nanowire arrays by adjusting dielectric shell thickness.

    PubMed

    Li, Xinhua; Chen, Tao; Zhou, BuKang; Liu, Guangqiang; Shi, Tongfei; Wen, Long; Cao, Huaxiang; Wang, Yuqi

    2017-05-05

    A low filling ratio and enhanced absorption is needed to enable the full potential of Si nanowire (NW) arrays for optoelectronic applications. In this paper, we report a versatile, scalable fabrication technique that uses nanosphere lithography (NSL) patterning for the synthesis of vertically aligned Si and Si/SiO2 NW arrays. The optical reflection of the NW arrays can be substantially suppressed by the addition of the transparent shell. Meanwhile, by the finite-difference time-domain (FDTD) simulation, we find that the absorption enhancement in the core Si NW can be obtained by adding the transparent shell. The special absorption enhancement of the Si NW arrays with a core-shell structure can be theoretically understood by modal analysis. The absorption in such Si NW array structures is very sensitive to the thickness of transparent coating. By the addition of a SiO2 shell layer, the absorption in the inner Si NW array can be substantially enhanced. Furthermore, significant absorption enhancement and broadband anti-reflection effects can be achieved by the diluted Si NWs combined with the single dielectric shell.

  6. Aluminide coatings

    SciTech Connect

    Henager, Jr; Charles, H; Shin, Yongsoon; Samuels, William D

    2009-08-18

    Disclosed herein are aluminide coatings. In one embodiment coatings are used as a barrier coating to protect a metal substrate, such as a steel or a superalloy, from various chemical environments, including oxidizing, reducing and/or sulfidizing conditions. In addition, the disclosed coatings can be used, for example, to prevent the substantial diffusion of various elements, such as chromium, at elevated service temperatures. Related methods for preparing protective coatings on metal substrates are also described.

  7. COATED ALLOYS

    DOEpatents

    Harman, C.G.; O'Bannon, L.S.

    1958-07-15

    A coating is described for iron group metals and alloys, that is particularly suitable for use with nickel containing alloys. The coating is glassy in nature and consists of a mixture containing an alkali metal oxide, strontium oxide, and silicon oxide. When the glass coated nickel base metal is"fired'' at less than the melting point of the coating, it appears the nlckel diffuses into the vitreous coating, thus providing a closely adherent and protective cladding.

  8. A novel method to fabricate silicon tubular gratings with broadband antireflection and super-hydrophobicity.

    PubMed

    Gao, Yang; Shi, Tielin; Tan, Xianhua; Liao, Guanglan

    2014-06-01

    We have developed a novel method to fabricate micro/nano structure based on the coherent diffraction lithography, and acquired periodic silicon tubular gratings with deep nano-scale tapered profiles at the top part. The optical properties of these tubular gratings were similar to an effective gradient-index antireflective surface, resulting in a broadband antireflective combining super-hydrophobic behavior. The mechanism of the method was simulated by rigorous coupled wave analysis algorithms. Then coherent diffraction lithography by use of suitable mask, in which periodic micro-scale circular opaque patters were distributed, was realized on the traditional aligner. Due to coherent diffraction, we obtained enough light intensity for photoresist exposure under the center of the opaque area in the mask together with transparent areas. The tapered line profiles and hollow photoresist gratings over large areas could be fabricated on the silicon wafer after development. The dry etching process was carried out, and high aspect ratio silicon tubular gratings with deep tapered profiles at the top were fabricated. The optical property and wettability of the structure were verified, proving that the proposed method and obtained micro/nano structure provide application potential in the future.

  9. Numerical Modeling of Sub-Wavelength Anti-Reflective Structures for Solar Module Applications.

    PubMed

    Han, Katherine; Chang, Chih-Hung

    2014-01-29

    This paper reviews the current progress in mathematical modeling of anti-reflective subwavelength structures. Methods covered include effective medium theory (EMT), finite-difference time-domain (FDTD), transfer matrix method (TMM), the Fourier modal method (FMM)/rigorous coupled-wave analysis (RCWA) and the finite element method (FEM). Time-based solutions to Maxwell's equations, such as FDTD, have the benefits of calculating reflectance for multiple wavelengths of light per simulation, but are computationally intensive. Space-discretized methods such as FDTD and FEM output field strength results over the whole geometry and are capable of modeling arbitrary shapes. Frequency-based solutions such as RCWA/FMM and FEM model one wavelength per simulation and are thus able to handle dispersion for regular geometries. Analytical approaches such as TMM are appropriate for very simple thin films. Initial disadvantages such as neglect of dispersion (FDTD), inaccuracy in TM polarization (RCWA), inability to model aperiodic gratings (RCWA), and inaccuracy with metallic materials (FDTD) have been overcome by most modern software. All rigorous numerical methods have accurately predicted the broadband reflection of ideal, graded-index anti-reflective subwavelength structures; ideal structures are tapered nanostructures with periods smaller than the wavelengths of light of interest and lengths that are at least a large portion of the wavelengths considered.

  10. 3D-Printed Broadband Dielectric Tube Terahertz Waveguide with Anti-Reflection Structure

    NASA Astrophysics Data System (ADS)

    Vogt, Dominik Walter; Leonhardt, Rainer

    2016-11-01

    We demonstrate broadband, low loss, and close-to-zero dispersion guidance of terahertz (THz) radiation in a dielectric tube with an anti-reflection structure (AR-tube waveguide) in the frequency range from 0.2 to 1.0 THz. The anti-reflection structure (ARS) consists of close-packed cones in a hexagonal lattice arranged on the outer surface of the tube cladding. The feature size of the ARS is in the order of the wavelength between 0.2 and 1.0 THz. The waveguides are fabricated with the versatile and cost efficient 3D-printing method. Terahertz time-domain spectroscopy (THz-TDS) measurements as well as 3D finite-difference time-domain simulations (FDTD) are performed to extensively characterize the AR-tube waveguides. Spectrograms, attenuation spectra, effective phase refractive indices, and the group-velocity dispersion parameters β 2 of the AR-tube waveguides are presented. Both the experimental and numerical results confirm the extended bandwidth and smaller group-velocity dispersion of the AR-tube waveguide compared to a low loss plain dielectric tube THz waveguide. The AR-tube waveguide prototypes show an attenuation spectrum close to the theoretical limit given by the infinite cladding tube waveguide.

  11. Numerical Modeling of Sub-Wavelength Anti-Reflective Structures for Solar Module Applications

    PubMed Central

    Han, Katherine; Chang, Chih-Hung

    2014-01-01

    This paper reviews the current progress in mathematical modeling of anti-reflective subwavelength structures. Methods covered include effective medium theory (EMT), finite-difference time-domain (FDTD), transfer matrix method (TMM), the Fourier modal method (FMM)/rigorous coupled-wave analysis (RCWA) and the finite element method (FEM). Time-based solutions to Maxwell’s equations, such as FDTD, have the benefits of calculating reflectance for multiple wavelengths of light per simulation, but are computationally intensive. Space-discretized methods such as FDTD and FEM output field strength results over the whole geometry and are capable of modeling arbitrary shapes. Frequency-based solutions such as RCWA/FMM and FEM model one wavelength per simulation and are thus able to handle dispersion for regular geometries. Analytical approaches such as TMM are appropriate for very simple thin films. Initial disadvantages such as neglect of dispersion (FDTD), inaccuracy in TM polarization (RCWA), inability to model aperiodic gratings (RCWA), and inaccuracy with metallic materials (FDTD) have been overcome by most modern software. All rigorous numerical methods have accurately predicted the broadband reflection of ideal, graded-index anti-reflective subwavelength structures; ideal structures are tapered nanostructures with periods smaller than the wavelengths of light of interest and lengths that are at least a large portion of the wavelengths considered.

  12. Highly Efficient Flexible Perovskite Solar Cells with Antireflection and Self-Cleaning Nanostructures.

    PubMed

    Tavakoli, Mohammad Mahdi; Tsui, Kwong-Hoi; Zhang, Qianpeng; He, Jin; Yao, Yan; Li, Dongdong; Fan, Zhiyong

    2015-10-27

    Flexible thin film solar cells have attracted a great deal of attention as mobile power sources and key components for building-integrated photovoltaics, due to their light weight and flexible features in addition to compatibility with low-cost roll-to-roll fabrication processes. Among many thin film materials, organometallic perovskite materials are emerging as highly promising candidates for high efficiency thin film photovoltaics; however, the performance, scalability, and reliability of the flexible perovskite solar cells still have large room to improve. Herein, we report highly efficient, flexible perovskite solar cells fabricated on ultrathin flexible glasses. In such a device structure, the flexible glass substrate is highly transparent and robust, with low thermal expansion coefficient, and perovskite thin film was deposited with a thermal evaporation method that showed large-scale uniformity. In addition, a nanocone array antireflection film was attached to the front side of the glass substrate in order to improve the optical transmittance and to achieve a water-repelling effect at the same time. It was found that the fabricated solar cells have reasonable bendability, with 96% of the initial value remaining after 200 bending cycles, and the power conversion efficiency was improved from 12.06 to 13.14% by using the antireflection film, which also demonstrated excellent superhydrophobicity.

  13. Organic small molecule-based optical coatings

    NASA Astrophysics Data System (ADS)

    Schulz, U.; Präfke, C.; Munzert, P.; Kaiser, N.

    2011-09-01

    A small molecule is a low molecular weight organic compound which is by definition not a polymer. Therefore, physical vapor deposition by evaporation as common for inorganic oxides is often possible. Organic layers can be useful as components of interference stacks for different functions. A number of organic compounds have interesting UV absorption characteristics and can be used to protect UV-sensitive polymers such as polycarbonate. In addition, organic layers can be applied to generate nanostructured thin films with a very low effective refractive index, as shown recently for polymers. A structured organic single layer can be applied as an antireflective (AR) coating for a glass lens. The applicability of several small molecule compounds will be discussed in this paper.

  14. Influence of polishing and coating techniques on laser induced damage on AR-coated ceramic Yb:YAG

    NASA Astrophysics Data System (ADS)

    De Vido, Mariastefania; Phillips, P. J.; Hein, Joachim; Körner, Jörg; Smith, Jodie M.; Ertel, Klaus; Mason, Paul D.; Banerjee, Saumyabrata; Cheklov, Oleg; Butcher, Thomas J.; Tomlinson, Stephanie; Lintern, Andrew; Greenhalgh, Justin; Shaikh, Waseem; Hawkes, Steve J.; Hernandez-Gomez, Cristina; Kaluza, Malte C.; Collier, John L.

    2014-10-01

    Yb3+ doped YAG is one of the most promising materials for high energy, high repetition rate laser systems producing nanosecond pulses. YAG as the host medium offers good thermo-mechanical and thermo-optical properties and, if it is used in ceramic form, it can be produced in large sizes with laser-grade optical properties. Large sized, laser-grade gain media are pivotal for the development of high energy kJ-class laser systems. Much effort has been devoted to the development of advanced polishing and coating techniques in order to produce optical materials able to withstand high fluence levels at different environmental conditions. In this paper, we present experimental results for 1 on 1 laser induced damage threshold (LIDT) tests in the nanosecond regime following ISO standards on anti-reflective coated ceramic Yb:YAG samples. Experimental results show that, generally, Ion Beam Sputtering (IBS) coatings perform better than Ion Assisted Deposition (IAD) coatings on low roughness substrates, while IAD and IBS coatings deposited on substrates characterised by higher surface roughness values offer a comparable performance. Performance of IBS coatings improves as substrate roughness decreases, whereas performance of IAD coatings improves as substrate roughness increases. No clear correlation has been observed between LIDT values and temperature or pressure. However, an inspection of damage sites allowed to conclude that both temperature and pressure have an impact on damage morphology.

  15. Excellent Passivation and Low Reflectivity Al2O3/TiO2 Bilayer Coatings for n-Wafer Silicon Solar Cells: Preprint

    SciTech Connect

    Lee, B. G.; Skarp, J.; Malinen, V.; Li, S.; Choi, S.; Branz, H. M.

    2012-06-01

    A bilayer coating of Al2O3 and TiO2 is used to simultaneously achieve excellent passivation and low reflectivity on p-type silicon. This coating is targeted for achieving high efficiency n-wafer Si solar cells, where both passivation and anti-reflection (AR) are needed at the front-side p-type emitter. It could also be valuable for front-side passivation and AR of rear-emitter and interdigitated back contact p-wafer cells. We achieve high minority carrier lifetimes {approx}1 ms, as well as a nearly 2% decrease in absolute reflectivity, as compared to a standard silicon nitride AR coating.

  16. Investigation of durability of optical coatings in highly purified tritium gas

    SciTech Connect

    Fischer, S.; Schoenung, K.; Bornschein, B.; Rolli, R.; Schaefer, V.; Sturm, M.

    2015-03-15

    Anti-reflection coated windows are part of Raman spectroscopy systems for tritium analytics in the KATRIN experiment and fusion-related applications. Damages of such windows were observed after three months of expo-sure to highly purified tritium gas in the LOOPINO facility. In this work, the origin of the damages was investigated, identified and eliminated. Coating samples manufactured by various physical vapor deposition methods have been tested for durability by exposure to pure tritium gas and subsequent visual inspection. Electron beam deposited coatings showed indications for damage after 17 days of tritium exposure in contrast to samples manufactured by ion assisted deposition or sputtering. An improved coating layout of the sample cell is presented for reliable long-term monitoring of tritium gas using Raman spectroscopy. (authors)

  17. An amorphous fluoropolymer: Next generation optical coating candidate

    SciTech Connect

    Chow, R.; Loomis, G.E.; Spragge, M.K.; Lindsey, E.L.; Rainer, F.; Ward, R.L.; Kozlowski, M.R.

    1994-05-01

    Anti-reflective (AR) and high reflector (HR) optical coatings were made by physical vapor deposition (PVD) of Teflon AF2400, a perfluorinated amorphous polymer. The AR had the highest laser damage thresholds recorded for PVD coatings at the Lawrence Livermore National Laboratory damage facility. The HR was a multilayer of ZnS and AF2400. The bandwidth was 550 mn, centered at 1064 mn. Single layers of Teflon AF2400 deposited by PVD were characterized optically. The refractive index could be intentionally reduced below the bulk value by varying either deposition rate or substrate temperature. Scanning electron microscopy and nuclear magnetic resonance observations indicated that morphological changes caused the variations in the refractive index rather than compositional changes.

  18. Zero infrared reflectance anomaly in doped silicon lamellar gratings. I. From antireflection to total absorption

    NASA Astrophysics Data System (ADS)

    Auslender, M.; Hava, S.

    1995-12-01

    Zero-reflectance phenomenon for a binary lamellar grating on n-Si substrate irradiated by normally incident TE polarized plane electromagnetic wave of wavelength 10.6 μm is studied. The treatment is performed in the strong diffraction regime, where the structural dimensions and the wavelength are of the same order of magnitude, using data on the IR dielectric function of bulk doped silicon and a version of rigorous coupled-wave analysis. The evolution of normal reflectance zeros with increasing electron concentration from dielecric to metallic-like n-Si is traced. It is shown that the groove height undergoes sharp increase and the period shrinks when plasma wavelength becomes equal to the radiation wavelength. This marks the transition from the antireflection to the total absorption regime where most of incident power is absorbed in the grating region. The cavity-resonance origin of total absorption and satellite peaks in the spectral response are discussed.

  19. Investigation of the neutral-solution etch process for refractive SOE antireflective surfaces

    SciTech Connect

    Maish, A.B.

    1991-01-01

    Antireflection of optically clear glass used in photovoltaic concentrator refractive secondary optical elements (SOE's) was investigated using the neutral-solution etch process developed by Schott Glass. Test coupons and SOE's made from barium zinc glass, which does not solarize under ultraviolet exposure, were successfully etched at the center point process variable conditions of 87{degrees}C and 24 hours. Reflectance of the plano-plano dropped from 7.7% to 0.8%, with a corresponding increase in transmission from 91.7% to 98.5%. The etching process uses non-hydrofluoric, relatively non-toxic chemicals in a low-cost process well suited for use by photovoltaic system manufacturers during production. 10 refs., 4 figs., 1 tab.

  20. An antireflection transparent conductor with ultralow optical loss (<2 %) and electrical resistance (<6 Ω sq-1)

    NASA Astrophysics Data System (ADS)

    Maniyara, Rinu Abraham; Mkhitaryan, Vahagn K.; Chen, Tong Lai; Ghosh, Dhriti Sundar; Pruneri, Valerio

    2016-12-01

    Transparent conductors are essential in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and solar cells. Here we demonstrate a transparent conductor with optical loss of ~1.6%, that is, even lower than that of single-layer graphene (2.3%), and transmission higher than 98% over the visible wavelength range. This was possible by an optimized antireflection design consisting in applying Al-doped ZnO and TiO2 layers with precise thicknesses to a highly conductive Ag ultrathin film. The proposed multilayer structure also possesses a low electrical resistance (5.75 Ω sq-1), a figure of merit four times larger than that of indium tin oxide, the most widely used transparent conductor today, and, contrary to it, is mechanically flexible and room temperature deposited. To assess the application potentials, transparent shielding of radiofrequency and microwave interference signals with ~30 dB attenuation up to 18 GHz was achieved.

  1. Infrared Wire-Grid Polarizer with Antireflection Structure by Imprinting on Both Sides

    NASA Astrophysics Data System (ADS)

    Yamada, Itsunari; Yamashita, Naoto; Tani, Kunihiko; Einishi, Toshihiko; Saito, Mitsunori; Fukumi, Kouhei; Nishii, Junji

    2012-08-01

    We fabricated infrared wire-grid polarizers with an antireflection (AR) grating structure by the simultaneous imprinting on both sides of a low-toxicity chalcogenide glass (Sb-Ge-Sn-S system). Silicon carbide and glassy carbon plates were used as molds for the direct glass imprinting. A wire-grid polarizer of 100-nm-thick was produced by depositing Al obliquely on the grating. Although the transmittance of the chalcogenide glass substrate was 62-66% in the 8.5-10.5 µm wavelength range, the transverse magnetic (TM) transmittance of the fabricated element became higher than 70% owing to the AR structure. The extinction ratio was larger than 20 dB at 11 µm wavelength.

  2. Fabrication of an anti-reflective microstructure on sapphire by femtosecond laser direct writing.

    PubMed

    Li, Qian-Kun; Cao, Jia-Ji; Yu, Yan-Hao; Wang, Lei; Sun, Yun-Lu; Chen, Qi-Dai; Sun, Hong-Bo

    2017-02-01

    Herein, we report a facile approach for the maskless production of subwavelength-structured antireflective surfaces on sapphire with high and broadband transmittance in the mid-IR: femtosecond laser direct writing assist with wet etching. With this method, inverted pyramid and cone arrays with a pitch of about 2 μm and a total height of near 900 nm on the sapphire were produced. The resulting subwavelength structures greatly suppress specular reflection at normal incidence. The transmission measurements between 3 and 5 μm are in agreement with the simulations performed using VirtualLab, and the transmittance reached a maximum value of 92.5% at 4 μm. The sapphire with subwavelength structures also exhibits angle-independent transmittance characteristics up to a high θ=60°. Therefore, these subwavelength structures on sapphire are of great technological importance in mid-IR optics, especially for the harsh-condition-applicable windows of military mid-IR devices.

  3. Maskless laser tailoring of conical pillar arrays for antireflective biomimetic surfaces.

    PubMed

    Wang, Lei; Xu, Bin-Bin; Chen, Qi-Dai; Ma, Zhuo-Chen; Zhang, Ran; Liu, Qing-Xue; Sun, Hong-Bo

    2011-09-01

    Herein, we report a facile approach for rapid and maskless production of subwavelength structured antireflective surfaces with high and broadband transmittance-direct laser interference ablation. The interfered laser beams were introduced into the surface of a bare optical substrate, where structured surfaces consisting of a micropillar array were produced by two-step laser irradiation in the time frame of seconds. A multiple exposure of the two-beam interference approach was proposed instead of multiple-beam interference to simply realize planar patterns of a high aspect ratio. Tall sinusoidal pillars were created and shaped by pulse shot number control. As an example of the application, zinc sulfide substrates were processed with the technology, from which high transmission at an infrared wavelength, over 92%, at normal incidence was experimentally achieved.

  4. Antireflective downconversion ZnO:Er3+,Yb3+ thin film for Si solar cell applications

    NASA Astrophysics Data System (ADS)

    Elleuch, R.; Salhi, R.; Deschanvres, J.-L.; Maalej, R.

    2015-02-01

    Hexagonal wurtzite phased ZnO:Er3+/Yb3+ thin films with various Yb concentrations were deposited on Si(111) substrate by Aerosol Assisted Chemical Vapor Deposition process. Post-annealed films at 1000 °C in air atmosphere showed a crystallinity enhancement. Yb3+ (4F7/2 → 4F5/2) 1000 nm emission increased with the increase of Yb3+ concentration emanating from an Er-Yb energy transfer. The reflectance percentage of 12% was achieved in the [250-1000 nm] range, and the refractive index of 1.97 was obtained for 632 nm wavelength. These results suggest that the (3 mol. % Er, 9 mol. % Yb) codoped film is a highly efficient antireflective downconversion layer for enhancing Si solar cell efficiency.

  5. Forming high-efficiency silicon solar cells using density-graded anti-reflection surfaces

    DOEpatents

    Yuan, Hao-Chih; Branz, Howard M.; Page, Matthew R.

    2015-07-07

    A method (50) is provided for processing a graded-density AR silicon surface (14) to provide effective surface passivation. The method (50) includes positioning a substrate or wafer (12) with a silicon surface (14) in a reaction or processing chamber (42). The silicon surface (14) has been processed (52) to be an AR surface with a density gradient or region of black silicon. The method (50) continues with heating (54) the chamber (42) to a high temperature for both doping and surface passivation. The method (50) includes forming (58), with a dopant-containing precursor in contact with the silicon surface (14) of the substrate (12), an emitter junction (16) proximate to the silicon surface (14) by doping the substrate (12). The method (50) further includes, while the chamber is maintained at the high or raised temperature, forming (62) a passivation layer (19) on the graded-density silicon anti-reflection surface (14).

  6. Nano-structured silicon surfaces with broadband and wide-angle antireflective properties for solar cells

    NASA Astrophysics Data System (ADS)

    Li, Zi-zheng; Gao, Jin-song; Yang, Hai-gui

    2015-10-01

    Silicon with various structural morphologies is widely used for solar cells and other optoelectronic devices. We present a new chemical etching process for nanoscale texturing of Si surfaces, which results in an almost complete suppression of the reflectivity in a broad spectral range, leading to black Si surfaces. The chemical etching process affects only the topmost 200-300 nm of the Si material. And it isn't dependent on the Si surface orientation and doping. Besides, the antireflective performance of reacted Si surface will highly improve with silver catalyst effect. Hence, it can be applied to various structural forms of bulk silicon as well as to thin Si films. The optical properties of various black Si samples are presented and discussed in correlation with the surface morphology, which are measured by atomic force microscope.

  7. 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.

  8. Superhydrophobic, antiadhesive, and antireflective surfaces mediated by hybrid biomimetic salvinia leaf with moth-eye structures

    NASA Astrophysics Data System (ADS)

    Yang, Cho-Yun; Tsai, Yu-Lin; Yang, Cho-Yu; Sung, Cheng-Kuo; Yu, Peichen; Kuo, Hao-Chung

    2014-08-01

    In this paper, we successfully demonstrate multifunctional surfaces based on scaffolding biomimetic structures, namely, hybrid salvinia leaves with moth-eye structures (HSMSs). The novel fabrication process employs scalable polystyrene nanosphere lithography and a lift-off process. Systematic characterizations show the biomimetic HSMS exhibiting superhydrophobic, self-cleaning, antiadhesive, and antireflective properties. Furthermore, the resulting surface tension gradient (known as the Marangoni effect) leads to a superior air retention characteristic in the HSMS under water droplet impact, compared with the traditional hybrid lotus leaf with a moth-eye structure (HLMS). Such results and learnings pave the way towards the attainment and mass deployment of dielectric surfaces with multiple functionalities for versatile biological and optoelectronic applications.

  9. Modification of nanostructured fused silica for use as superhydrophobic, IR-transmissive, anti-reflective surfaces

    NASA Astrophysics Data System (ADS)

    Boyd, Darryl A.; Frantz, Jesse A.; Bayya, Shyam S.; Busse, Lynda E.; Kim, Woohong; Aggarwal, Ishwar; Poutous, Menelaos; Sanghera, Jasbinder S.

    2016-04-01

    In order to mimic and enhance the properties of moth eye-like materials, nanopatterned fused silica was chemically modified to produce self-cleaning substrates that have anti-reflective and infrared transmissive properties. The characteristics of these substrates were evaluated before and after chemical modification. Furthermore, their properties were compared to fused silica that was devoid of surface features. The chemical modification imparted superhydrophobic character to the substrates, as demonstrated by the average water contact angles which exceeded 170°. Finally, optical analysis of the substrates revealed that the infrared transmission capabilities of the fused silica substrates (nanopatterned to have moth eye on one side) were superior to those of the regular fused silica substrates within the visible and near-infrared region of the light spectrum, with transmission values of 95% versus 92%, respectively. The superior transmission properties of the fused silica moth eye were virtually unchanged following chemical modification.

  10. Forming high efficiency silicon solar cells using density-graded anti-reflection surfaces

    DOEpatents

    Yuan, Hao-Chih; Branz, Howard M.; Page, Matthew R.

    2014-09-09

    A method (50) is provided for processing a graded-density AR silicon surface (14) to provide effective surface passivation. The method (50) includes positioning a substrate or wafer (12) with a silicon surface (14) in a reaction or processing chamber (42). The silicon surface (14) has been processed (52) to be an AR surface with a density gradient or region of black silicon. The method (50) continues with heating (54) the chamber (42) to a high temperature for both doping and surface passivation. The method (50) includes forming (58), with a dopant-containing precursor in contact with the silicon surface (14) of the substrate (12), an emitter junction (16) proximate to the silicon surface (14) by doping the substrate (12). The method (50) further includes, while the chamber is maintained at the high or raised temperature, forming (62) a passivation layer (19) on the graded-density silicon anti-reflection surface (14).

  11. Development of a Multi-layer Anti-reflective Coating for Gallium Arsenide/Aluminum Gallium Arsenide Solar Cells

    DTIC Science & Technology

    2015-07-01

    of the solar cell actually end up in the active region able to convert photon energy into electrical energy . Several mechanisms contribute to energy ...and therefore, generate more photocurrent in the solar cell. As the photon having energy equal to or greater than the bandgap travels into the...Reflectance: 3 to light. QE is the ratio of the number of carriers collected by the solar cell to the number of photons of a given energy incident on

  12. Fabrication of highly transparent diamond-like carbon anti-reflecting coating for Si solar cell application

    SciTech Connect

    Banerjee, Amit Das, Debajyoti

    2014-04-24

    ARC grade highly transparent unhydrogenated diamond-like carbon (DLC) films were produced, directly from a-C target, using RF magnetron sputtering deposition technique, for optoelectronic applications. Optical band gap, transmittance, reflectance, sp{sup 3} fraction, I{sub D}/I{sub G}, density, and refractive index of the films have been estimated with the help of optical tools like Uv-vis spectrophotometer, ellipsometer and micro-Raman. Optimum ARC-qualities have been identified in low-temperature grown DLC films at an Ar pressure of 4 mTorr in the reactor, accomplishing its key requirements for use in silicon solar cells.

  13. High Si content anti-reflective coatings and their extension to a UV freeze dual patterning process

    NASA Astrophysics Data System (ADS)

    Kennedy, Joseph; Wu, ZeYu; Flanigan, Kyle; Dai, Junyan; Wallow, Thomas

    2009-12-01

    As IC manufactures explore different paths to meet the resolution requirements for next generation technology, patterning schemes which utilize a double photoresist patterning process are under extensive evaluation. One dual patterning process under consideration uses a 172nm UV cure to render the first photoresist pattern insoluble to the casting solvents and developer chemistries used to define the second photoresist pattern. Line-space resist patterning is used to understand the effect of the 172nm UV light on the SiBARC, under-layer film stack and how it influences the patterned CD. This is followed by cross-grid and pitch-split double patterning using 172 nm UV light of varying dose to freeze the first photoresist layer patterned using a tri-layer film configuration. In the final section we discuss the effects of the 172nm UV cure on the SiBARC film thickness and optical properties. Simulations are run to understand the change in the focus-exposure process window due to changes in the SiBARC film due to the 172nm UV cure.

  14. Efficiency enhancement InGaP/GaAs dual-junction solar cell with subwavelength antireflection nanorod arrays.

    PubMed

    Tsai, Min-An; Chen, Hsin Chu; Tseng, Ping Chen; Yu, Peichen; Chiu, Chin Hua; Kuo, Hao Chung; Lin, Shiuan Huei

    2011-12-01

    The enhanced conversion efficiency of the InGaP/GaAs dual-junction solar cell was demonstrated utilizing broad-band and omnidirectional antireflection nanorod arrays. The nanorod arrays were fabricated by self-assembled Ni clusters, followed by inductively-coupled-plasma reactive ion etching. The conversion efficiency measured under one-sun air mass 1.5 global illuminations at room temperature was improved by 10.8%. The light absorption efficiencies of the top InGaP and bottom GaAs cells were also studied under the influence of nanorod arrays. The enhanced absorption efficiency was mostly contributed from the short wavelength absorption by top cell. Surface nanorod arrays served not only as broad-band omnidirectional antireflection layers but also scattering sources. The structure can be further optimized to obtain the maximum conversion efficiency.

  15. Anti- reflective device having an anti-reflection surface formed of silicon spikes with nano-tips

    NASA Technical Reports Server (NTRS)

    Bae, Youngsman (Inventor); Mooasser, Sohrab (Inventor); Manohara, Harish (Inventor); Lee, Choonsup (Inventor); Bae, Kungsam (Inventor)

    2009-01-01

    Described is a device having an anti-reflection surface. The device comprises a silicon substrate with a plurality of silicon spikes formed on the substrate. A first metallic layer is formed on the silicon spikes to form the anti-reflection surface. The device further includes an aperture that extends through the substrate. A second metallic layer is formed on the substrate. The second metallic layer includes a hole that is aligned with the aperture. A spacer is attached with the silicon substrate to provide a gap between an attached sensor apparatus. Therefore, operating as a Micro-sun sensor, light entering the hole passes through the aperture to be sensed by the sensor apparatus. Additionally, light reflected by the sensor apparatus toward the first side of the silicon substrate is absorbed by the first metallic layer and silicon spikes and is thereby prevented from being reflected back toward the sensor apparatus.

  16. Low-cost, flexible, and self-cleaning 3D nanocone anti-reflection films for high-efficiency photovoltaics.

    PubMed

    Tsui, Kwong-Hoi; Lin, Qingfeng; Chou, Hungtao; Zhang, Qianpeng; Fu, Huiying; Qi, Pengfei; Fan, Zhiyong

    2014-05-01

    Low-cost engineered nanotemplates are used to mold flexible nanocone anti-reflection (AR) films. Both optical reflectance measurements and photovoltaics characterizations demonstrate that the flexible nanocone AR films can considerably suppress device front-side reflectance and thus improve the power conversion efficiency of high-efficiency thin-film CdTe solar cells. Additionally, these nanocone AR films are found to be superhydrophobic and thus possess self-cleaning capability.

  17. Flat-top and patterned-topped cone gratings for visible and mid-infrared antireflective properties.

    PubMed

    Brückner, Jean-Baptiste; Le Rouzo, Judikaël; Escoubas, Ludovic; Berginc, Gérard; Gourgon, Cécile; Desplats, Olivier; Simon, Jean-Jacques

    2013-07-01

    Achieving a broadband antireflection property from material surfaces is one of the highest priorities for those who want to improve the efficiency of solar cells or the sensitivity of photo-detectors. To lower the reflectance of a surface, we are concerned with the study of the optical response of flat-top and patterned-topped cone shaped silicon gratings, based on previous work exploring pyramid gratings. Through rigorous numerical methods such as Finite Different Time Domain, we first designed several flat-top structures that theoretically demonstrate an antireflective character within the middle infrared region. From the opto-geometrical parameters such as period, depth and shape of the pattern determined by numerical analysis, these structures have been fabricated using controlled slope plasma etching processes. In order to extend the antireflective properties up to the visible wavelengths, patterned-topped cones have been fabricated as well. Afterwards, optical characterizations of several samples were carried out. Thus, the performances of the flat-top and patterned-topped cones have been compared in the visible and mid infrared range.

  18. Structure and antireflection properties of SiNWs arrays form mc-Si wafer through Ag-catalyzed chemical etching

    NASA Astrophysics Data System (ADS)

    Li, Shaoyuan; Ma, Wenhui; Chen, Xiuhua; Xie, Keqiang; Li, Yuping; He, Xiao; Yang, Xi; Lei, Yun

    2016-04-01

    A simple and low cost MACE method was demonstrated for efficiently texturing commercial mc-Si wafer at room temperature. The effects of fabrication parameters (deposition time, HF concentration, H2O2 concentration, and etching time) on the morphology structure, antireflection property of textured mc-Si were carefully studied. The large scale SiNWs arrays with different structure can be obtained under various fabrication conditions. Meanwhile, the results indicate that the fabricate parameters have important effect on the reflectance of textured mc-Si sample in the order of etching time > deposition time > H2O2 concentration > HF concentration. The comprehensive research results indicate that it is more beneficial for the nanowire arrays with tapering structure and the length of 13 μm to obtain excellent antireflection property. Under these optimization conditions, the textured mc-Si shows an outstanding anti-reflectance ability of ∼5.6%, which indicates that the Ag-catalysis etched mc-Si shows a huge potential application in high-efficiency polysilicon solar cells.

  19. Hydroxyapatite coatings.

    PubMed

    Lacefield, W R

    1988-01-01

    Four coating techniques were evaluated to determine which is most suitable for producing a dense, highly adherent coating onto metallic and ceramic implant materials. Two of the selected coating methods have serious limitations for use in this particular application, and did not meet the specified criteria for satisfactory coating as defined in the initial stages of the study. For example, the dip coating-sintering technique was judged to be unsatisfactory because of the adverse effect of the high-temperature sintering cycle on the mechanical properties of the metallic substrate materials. These materials could not be used in load-bearing applications because of the excessive grain growth and loss of the wrought structure of both the commercially pure Ti and Ti-6Al-4V substrates, and the loss of ductility in the cast Co-Cr-Mo alloy. Another area of concern was that bond strength between the HA coating and the substrate was not high enough to insure that interfacial failure would not occur during the lifetime of the implant. The immersion-coating technique, in which the metal substrate is immersed into the molten ceramic, was shown in a previous study to be the best method of coating a bioreactive glass onto a Co-Cr-Mo implant. Heating HA above its melting temperature, however, caused undesired compositional and structural changes, and upon solidification very limited adherence between the modified ceramic and substrate material occurred under the conditions of this study. The HIP technique, in which the Ti powder substrate and the HA powder coating are sintered together in a high-pressure autoclave, shows great promise for the fabrication of high-quality composite implants. Initial studies have indicated that high-density Ti substrates with a small grain size that are well bonded to a dense HA coating can be produced under optimum conditions. Sintering and densification additives, such as SiO2 powder, do not appear to be necessary. The main drawback to this

  20. Towards perfect light coupling and absorption in nanomembranes with omni-directional anti-reflection and photonic crystal structures

    NASA Astrophysics Data System (ADS)

    Chadha, Arvinder Singh

    investigated in detail. The front-surface Fresnel reflection is reduced with the incorporation of an omni-directional anti-reflection coating (Omni-ARC) based on nanostructures or by deposition of graded refractive index (GRIN) films. A design methodology based on the comparison of the rate of change of the refractive index profile of nanostructures of different shapes and thickness as an equivalent GRIN film suggests the minimum feature size needed to give near perfect ARC. Numerical models were built to account for the non - uniform GRIN film deposition on both rigid and flexible, flat and curved surfaces resulting from the variation in the resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) process technology. With the miniaturization of the devices, the effect of finite beam size and finite active area of the photonic components on the optical properties like transmission, reflection and scattering loss was studied as well. All the numerical studies presented in the thesis are validated by experimental results.

  1. Sol-gel preparation and characterization of SiO2 coated VO2 films with enhanced transmittance and high thermochromic performance

    NASA Astrophysics Data System (ADS)

    Li, Dezeng; Shan, Yongkui; Huang, Fuqiang; Ding, Shangjun

    2014-10-01

    Vanadium dioxide (VO2) films prepared at low-temperature with a low cost are considerable for energy-saving applications. Here, SiO2 coated VO2 films with clearly enhanced visible transmittance by introducing antireflection coatings (ARCs) and excellent thermochromic performance were present. The VO2 films have been prepared via a stable and low-cost sol-gel synthesis route using vanadium pentaoxide powder as precursor, and their structural, morphological, optical and electrical properties and thermochromic performance were systemically characterized. The resistance of VO2 films varies by 4 orders of magnitude and the transmittance changes from 11.8% to 69.3% at 2500 nm while no significant deviation appears in the visible region during metal-insulator transition (MIT). Nanoporous SiO2 coating with good optical transparency was coated on the surface of VO2 film via sol-gel dip-coating technique to enhance its optical transmittance, and the visible transmittance is increased by 14.6% due to the significantly decreased reflectance. The critical transition temperature (63 °C) and infrared switching properties of VO2 films are not much deteriorated by applying SiO2 layer. The synergistic effect of antireflection and thermochromism on SiO2 coated VO2 films was investigated.

  2. Optical coatings of variable refractive index and high laser-resistance from physical-vapor-deposited perfluorinated amorphous polymer

    DOEpatents

    Chow, Robert; Loomis, Gary E.; Thomas, Ian M.

    1999-01-01

    Variable index optical single-layers, optical multilayer, and laser-resistant coatings were made from a perfluorinated amorphous polymer material by physical vapor deposition. This was accomplished by physically vapor depositing a polymer material, such as bulk Teflon AF2400, for example, to form thin layers that have a very low refractive index (.about.1.10-1.31) and are highly transparent from the ultra-violet through the near infrared regime, and maintain the low refractive index of the bulk material. The refractive index can be varied by simply varying one process parameter, either the deposition rate or the substrate temperature. The thus forming coatings may be utilized in anti-reflectors and graded anti-reflection coatings, as well as in optical layers for laser-resistant coatings at optical wavelengths of less than about 2000 nm.

  3. Optical coatings of variable refractive index and high laser-resistance from physical-vapor-deposited perfluorinated amorphous polymer

    DOEpatents

    Chow, R.; Loomis, G.E.; Thomas, I.M.

    1999-03-16

    Variable index optical single-layers, optical multilayer, and laser-resistant coatings were made from a perfluorinated amorphous polymer material by physical vapor deposition. This was accomplished by physically vapor depositing a polymer material, such as bulk Teflon AF2400, for example, to form thin layers that have a very low refractive index (ca. 1.10--1.31) and are highly transparent from the ultra-violet through the near infrared regime, and maintain the low refractive index of the bulk material. The refractive index can be varied by simply varying one process parameter, either the deposition rate or the substrate temperature. The thus forming coatings may be utilized in anti-reflectors and graded anti-reflection coatings, as well as in optical layers for laser-resistant coatings at optical wavelengths of less than about 2000 nm. 2 figs.

  4. Regulatory Aspects of Coatings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter gives a history of the development and uses of edible coating regulations, detailed chapters on coating caracteristics, determination of coating properties, methods for making coatings, and discription of coating film formers (polysaccharieds, lipids, resins, proteins). The chapter also...

  5. Enhanced power generation in concentrated photovoltaics using broadband antireflective coverglasses with moth eye structures.

    PubMed

    Song, Young Min; Jeong, Yonkil; Yeo, Chan Il; Lee, Yong Tak

    2012-11-05

    We present the effect of broadband antireflective coverglasses (BARCs) with moth eye structures on the power generation capability of a sub-receiver module for concentrated photovoltaics. The period and height of the moth eye structures were designed by a rigorous coupled-wave analysis method in order to cover the full solar spectral ranges without transmission band shrinkage. The BARCs with moth eye structures were prepared by the dry etching of silver (Ag) nanomasks, and the fabricated moth eye structures on coverglass showed strongly enhanced transmittance compared to the bare glass with a flat surface, at wavelengths of 300 - 1800 nm. The BARCs were mounted on InGaP/GaAs/Ge triple-junction solar cells and the power conversion efficiency of this sub-receiver module reached 42.16% for 196 suns, which is a 7.41% boosted value compared to that of a module with bare coverglass, without any detrimental changes of the open circuit voltages (V(oc)) and fill factor (FF).

  6. Broadband terahertz anti-reflective structure fabricated by femtosecond laser drilling technique

    NASA Astrophysics Data System (ADS)

    Zhang, Yibin; Yuan, Minghui; Chen, Lin; Cai, Bin; Yang, Rui; Zhu, Yiming

    2016-02-01

    We fabricated several reverse conical holes on high-resistivity silicon substrate with different power and pulse number of femtosecond laser, and investigated their patterns and features by using scanning electron microscope (SEM). Then, we chose one of the experimental parameters prepared a reverse conical anti-reflection structure sample with period of 90 μm. Terahertz Time-domain Spectroscopy (THz-TDS) was used to test its properties. Compared with the nonstructural high-resistivity silicon, the transmission of structural high-resistivity silicon increases by the maximum of 14% in the range 0.32-1.30 THz. Furthermore, we simulated the sample by finite integral method (FIM). The simulated results show good consistency with experimental results. The transmission effect of the reverse conical holes were optimized via simulation. Results show that the related transmission effect can be improved by increasing the pulse numbers and decreasing the spot size of the femtosecond laser. The different transmission window can also be tuned by changing the reverse conical structure of different periods.

  7. Multifunctional porous silicon nanopillar arrays: antireflection, superhydrophobicity, photoluminescence, and surface-enhanced Raman scattering (SERS)

    PubMed Central

    Kiraly, Brian; Yang, Shikuan

    2014-01-01

    We have fabricated porous silicon nanopillar arrays over large areas with a rapid, simple, and low-cost technique. The porous silicon nanopillars show unique longitudinal features along their entire length and have porosity with dimensions on the single-nanometer scale. Both Raman spectroscopy and photoluminescence data were used to determine the nanocrystallite size to be < 3 nm. The porous silicon nanopillar arrays also maintained excellent ensemble properties, reducing reflection nearly fivefold from planar silicon in the visible range without any optimization and approaching superhydrophobic behavior with increasing aspect ratio, demonstrating contact angles up to 138°. Finally, the porous silicon nanopillar arrays were made into sensitive surface enhanced Raman scattering (SERS) substrates by depositing metal onto the pillars. The SERS performance of the substrates was demonstrated using a chemical dye Rhodamine 6G. With their multitude of properties (i.e., antireflection, superhydrophobicity, photoluminescence, and sensitive SERS), the porous silicon nanopillar arrays described here can be valuable in applications such as solar harvesting, electrochemical cells, self-cleaning devices, and dynamic biological monitoring. PMID:23703091

  8. Large-Aperture Wide-Bandwidth Anti-Reflection-Coated Silicon Lenses for Millimeter Wavelengths

    NASA Technical Reports Server (NTRS)

    Datta, R.; Munson, C. D.; Niemack, M. D.; McMahon, J. J.; Britton, J.; Wollack, E. J.; Beall, J.; Devlin, M. J.; Fowler, J.; Gallardo, P.; Hubmayr, J.; Irwin, K.; Newburgh, L.; Nibarger, J. P.; Page, L.; Quijada, M. A.; Schmitt, B. L.; Staggs, S. T.; Thornton, R.; Zhang, L.

    2013-01-01

    The increasing scale of cryogenic detector arrays for sub-millimeter and millimeter wavelength astrophysics has led to the need for large aperture, high index of refraction, low loss, cryogenic refracting optics. Silicon with n = 3.4, low loss, and relatively high thermal conductivity is a nearly optimal material for these purposes, but requires an antireflection (AR) coating with broad bandwidth, low loss, low reflectance, and a matched coffecient of thermal expansion. We present an AR coating for curved silicon optics comprised of subwavelength features cut into the lens surface with a custom three axis silicon dicing saw. These features constitute a metamaterial that behaves as a simple dielectric coating. We have fabricated and coated silicon lenses as large as 33.4 cm in diameter with coatings optimized for use between 125-165 GHz. Our design reduces average reflections to a few tenths of a percent for angles of incidence up to 30 deg. with low cross-polarization. We describe the design, tolerance, manufacture, and measurements of these coatings and present measurements of the optical properties of silicon at millimeter wavelengths at cryogenic and room temperatures. This coating and lens fabrication approach is applicable from centimeter to sub-millimeter wavelengths and can be used to fabricate coatings with greater than octave bandwidth.

  9. Spectral Control of Transmission of Diffuse Irradiation using Piled AR Coated Quartz Glass Filters

    NASA Astrophysics Data System (ADS)

    Kumano, Tomoyuki; Hanamura, Katsunori

    2004-11-01

    Spectral transmission characteristics of piled quartz glass filters with anti-reflection (AR) coating and without coating were investigated for diffuse irradiation through ray tracing numerical simulation. The spectral transmittance for diffuse irradiation is lower than that for normal irradiation because surface reflection becomes large with increasing incident zenith angle. By using the AR coating, the transmittance for diffuse irradiation becomes much higher than that without coating around a wavelength of 1.1 μm that is specified for the coating thickness design. On the other hand, for the long wavelength region, the transmittance reduced largely due to multiple-surface and absorption. The most striking feature is that difference between transmittances for the specified and the long wavelength region is enhanced using the piled AR coated quartz glass filters. If the refractive index of the coating material were 1.19, which was an ideal value for the design of the coating, the effect is the most remarkable. As a result, it is revealed that this spectral control method is useful for the energy recirculation TPV system using super-adiabatic combustion in porous media.

  10. High Performance Laser Amplifiers at 1.5 μm using E-Gum Evaporated Hafnium Di-Oxide Coatings

    NASA Astrophysics Data System (ADS)

    Tiemeijer, L. F.; Kuindersma, P. I.; Krekels, H. C. J.; Es-Spiekman, W. v.; Hendrix, L. J. M.; Ludwig, R.; Küller, L.

    1990-02-01

    E-gun evaporated Hafnium di-Oxide anti-reflective coatings are shown to be an attractive alternative for sputtered Silicon Oxide AR coatings. Laser amplifiers were fabricated using this material and a modal reflectivity as low as 1.7× 10-4 was obtained. A single pass gain of 26 dB together with a ripple as low as 2 dB for the TE mode were measured. Furthermore a 3 dB output saturation power of {+}8 dBm and a fiber coupling loss of 3.5 dB/facet were measured.

  11. Versatile Coating

    NASA Technical Reports Server (NTRS)

    1990-01-01

    A radome at Logan Airport and a large parabolic antenna at the Wang Building in Massachusetts are protected from weather, corrosion and ultraviolet radiation by a coating, specially designed for antennas and radomes, known as CRC Weathertite 6000. The CRC 6000 line that emerged from Boyd Coatings Research Co., Inc. is a solid dispersion of fluorocarbon polymer and polyurethane that yields a tough, durable film with superior ultraviolet resistance and the ability to repel water and ice over a long term. Additionally, it provides resistance to corrosion, abrasion, chemical attacks and impacts. Material can be used on a variety of substrates, such as fiberglass, wood, plastic and concrete in addition to steel and aluminum. In addition Boyd Coatings sees CRC 6000 applicability as an anti-icing system coated on the leading edge of aircraft wings.

  12. Protective Coating

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Inorganic Coatings, Inc.'s K-Zinc 531 protective coating is water-based non-toxic, non-flammable and has no organic emissions. High ratio silicate formula bonds to steel, and in 30 minutes, creates a very hard ceramic finish with superior adhesion and abrasion resistance. Improved technology allows application over a minimal commercial sandblast, fast drying in high humidity conditions and compatibility with both solvent and water-based topcoats. Coating is easy to apply and provides long term protection with a single application. Zinc rich coating with water-based potassium silicate binder offers cost advantages in materials, labor hours per application, and fewer applications over a given time span.

  13. Vacuum deposited optical coatings experiment (AO 138-4)

    NASA Technical Reports Server (NTRS)

    Charlier, Jean

    1991-01-01

    The aim of this experiment was to test the optical behavior of 20 components and coatings subjected to space exposure. Most of them are commonly used for their reflective or transmittive properties in spaceborne optics. They consist in several kind of metallic and dielectric mirrors designed for the 0.12 to 10 microns spectrum, UV, and NIR bandpass filters, visible, and IR antireflecting coatings, visible/IR dichroic beam splitters, and visible beam splitter. The coatings were deposited on various substrates such as glasses, germanium, magnesium fluoride, quartz, zinc selenide, and kanigened aluminum. Several coating materials were used such as Al, Ag, Au, MgF2, LaF3, ThF3, ThF4, SiO2, TiO2, ZrO2, Al2O3, MgO, Ge, and ZnSe. Five samples of each component were manufactured. Two flight samples were mounted in such a way that one was directly exposed to space and the other looking backwards. The same arrangement was used for the spare samples stored on ground in a box identical to the flight one and they were kept under vacuum during the LDEF mission. Finally, one set of reference components was stocked in a sealed box under a dry nitrogen atmosphere. By comparing the preflight and postflight optical performances of the five samples of each component, it is possible to detect the degradations due to the space exposure.

  14. Coatings for high energy applications. The Nova laser

    SciTech Connect

    Wirtenson, G.R.

    1986-01-01

    The combined requirements of energy density, multiple wavelength, and aperture make the coatings for the Nova Inertial Confinement Fusion (ICF) laser unique. This ten beam neodymium glass laser system, built at the Lawrence Livermore National Laboratory (LLNL), has over a thousand major optical components; some larger than one meter in diameter and weighing 380 Kg. The laser operates at 1054 nm and can be frequency doubled to 527 nm or tripled to 351 nm by means of full aperture potassium dihydrogen phosphate (KDP) crystal arrays. The 1.0 nsec fluence varies along the laser chain, sometimes reaching values as high as 16 J/cm/sup 2/ at the input lens to one of the spatial filters. The design specifications of this massive optical system were changed several times as the state-of-the-art advanced. Each change required redesign of the optical coatings even as vendors were preparing for production runs. Frequency conversion to include shorter wavelengths mandated the first major coating redesign and was followed almost immediately by a second redesign to reduce solarization effects in borosilicate crown glass. The conventional thermal evaporation process although successful for the deposition of mirror coatings, was not able to produce antireflection coatings able to survive the locally high chain fluences. As a consequence it became necessary to develop another technique. Solution produced coatings were developed having transmissions exceeding 99% per part and damage threshold values equal to the bare substrate. The unique requirement of the Nova laser necessitated special deposition and metrology equipment. These programmatic developments will be reviewed in the context of the cooperative working relationship developed between LLNL and its vendors. It was this excellent relationship which has enabled LLNL to obtain these highly specialized coatings for the Nova laser.

  15. Coatings for high energy applications. The Nova laser

    NASA Astrophysics Data System (ADS)

    Wirtenson, G. R.

    The combined requirements of energy density, multiple wavelength, and aperture make the coatings for the Nova Inertial Confinement Fusion (ICF) laser unique. This ten beam neodymium glass laser system, built at the Lawrence Livermore National Laboratory (LLNL), has over a thousand major optical components; some larger than one meter in diameter and weighing 380 Kg. The laser operates at 1054 nm and can be frequency doubled to 527 nm or tripled to 351 nm by means of full aperture potassium dihydrogen phosphate (KDP) crystal arrays. The 1.0 nsec fluence varies along the laser chain, sometimes reaching values as high as 16 J/cm(2) at the input lens to one of the spatial filters. The design specifications of this massive optical system were changed several times as the state-of-the-art advanced. Each change required redesign of the optical coatings even as vendors were preparing for production runs. Frequency conversion to include shorter wavelengths mandated the first major coating redesign and was followed almost immediately by a second redesign to reduce solarization effects in borosilicate crown glass. The conventional thermal evaporation process although successful for the deposition of mirror coatings, was not able to produce antireflection coatings able to survive the locally high chain fluences. As a consequence it became necessary to develop another technique. Solution produced coatings were developed having transmissions exceeding 99% per part and damage threshold values equal to the bare substrate. The unique requirement of the Nova laser necessitated special deposition and metrology equipment. These programmatic developments will be reviewed in the context of the cooperative working relationship developed between LLNL and its vendors. It was this excellent relationship which has enabled LLNL to obtain these highly specialized coatings for the Nova laser.

  16. A two-in-one superhydrophobic and anti-reflective nanodevice in the grey cicada Cicada orni (Hemiptera)

    SciTech Connect

    Dellieu, Louis Sarrazin, Michaël Simonis, Priscilla; Deparis, Olivier; Vigneron, Jean Pol

    2014-07-14

    Two separated levels of functionality are identified in the nanostructure which covers the wings of the grey cicada Cicada orni (Hemiptera). The upper level is responsible for superhydrophobic character of the wing, while the lower level enhances its anti-reflective behavior. Extensive wetting experiments with various chemical species and optical measurements were performed in order to assess the bi-functionality. Scanning electron microscopy imaging was used to identify the nanostructure morphology. Numerical optical simulations and analytical wetting models were used to prove the roles of both levels of the nanostructure. In addition, the complex refractive index of the chitinous material of the wing was determined from measurements.

  17. A two-in-one superhydrophobic and anti-reflective nanodevice in the grey cicada Cicada orni (Hemiptera)

    NASA Astrophysics Data System (ADS)

    Dellieu, Louis; Sarrazin, Michaël; Simonis, Priscilla; Deparis, Olivier; Vigneron, Jean Pol

    2014-07-01

    Two separated levels of functionality are identified in the nanostructure which covers the wings of the grey cicada Cicada orni (Hemiptera). The upper level is responsible for superhydrophobic character of the wing, while the lower level enhances its anti-reflective behavior. Extensive wetting experiments with various chemical species and optical measurements were performed in order to assess the bi-functionality. Scanning electron microscopy imaging was used to identify the nanostructure morphology. Numerical optical simulations and analytical wetting models were used to prove the roles of both levels of the nanostructure. In addition, the complex refractive index of the chitinous material of the wing was determined from measurements.

  18. Fabrication of hierarchical anti-reflective structures using polystyrene sphere lithography on an as-cut p-Si substrate

    NASA Astrophysics Data System (ADS)

    Chou, Yen-Yu; Lee, Kuan-Tao; Lee, Yeeu-Chang

    2016-07-01

    The broadband anti-reflective (AR) properties of hierarchical structures (HSs) have attracted considerable attention in recent years as a means to reduce Fresnel reflection in photovoltaic solar cell materials. This study employed polystyrene sphere lithography in conjunction with high density plasma dry etching in the fabrication of pure sub-wavelength structures and HSs on an as-cut p-Si substrate. Etching parameters, such as RF power, O2, and etching time, were adjusted to alter the surface morphology. Experiment results demonstrate that the resulting hierarchical paraboloidal structures suppress average reflectance to below 0.5% across a spectral range of 500-1000 nm.

  19. Efficiency enhancement of silicon solar cells using a nano-scale honeycomb broadband anti-reflection structure.

    PubMed

    Huang, C K; Sun, K W; Chang, W-L

    2012-01-02

    This experiment demonstrates the process for manufacturing a ZnO honeycomb sub-wavelength structure using nanosphere lithography technology exhibiting excellent anti-reflection properties from the UV to NIR wavelength regions. This honeycomb nanostructure, combined with commercially available crystalline Si solar cells, show substantially improved conversion efficiency from 15.6% to 16.6% using optimized honeycomb sizes and precursor concentrations of ZnO. The present work develops an unsophisticated and economical technique suitable for industrial applications in producing a uniform and low-reflective texture.

  20. Characterization of the optical properties of hydrophobic coatings and realization of high performance AR coatings with dust- and water-repellent properties

    NASA Astrophysics Data System (ADS)

    Bruynooghe, S.; Spinzig, S.; Fliedner, M.; Hsu, G. J.

    2008-09-01

    Hydrophobic coatings enable the manufacture of easy-to-clean surfaces having dust- and water-repellent properties. In this work, a hydrophobic coating is deposited as a top layer on an antireflective (AR) multilayer system comprising a MgF2 upper layer to produce low reflectance optical surfaces at a normal incident angle in the visible spectrum with dust- and water-repellent properties for applications in precision optics. We report on the preparation and characterization of the optical properties of hydrophobic coatings deposited using a vacuum evaporation process and a commercially available water repellent substance. By means of a grazing incidence X-ray reflectometer it is shown that the hydrophobic coating can be considered, from an optical point of view, as two adjacent thin layers having specific thicknesses and densities. In fact, the hydrophobic layer is one monolayer comprising molecular chains with anchoring groups responsible for the chemical bond with the substrate material and functional groups responsible for the water- and oil-repellent properties. Optical constants are determined using a spectroscopic ellipsometer and are taken into account in the final multilayer system design. High performance AR coatings having an average reflectance of 0.14% at 7° incident angle in the 400-680nm spectral range together with a pleasing purple-red reflex color are produced. Coated lenses exhibit an excellent abrasion resistance, environmental stability, resistance to cleaning agents, homogeneity and water repellence with contact angles against water higher than 110°.

  1. Diamond Coatings

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Advances in materials technology have demonstrated that it is possible to get the advantages of diamond in a number of applications without the cost penalty, by coating and chemically bonding an inexpensive substrate with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous technical and economic potential in such advances as chemically inert protective coatings; machine tools and parts capable of resisting wear 10 times longer; ball bearings and metal cutting tools; a broad variety of optical instruments and systems; and consumer products. Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate. Diamonex is developing, and offering commercially, under the trade name Diamond Aegis, a line of polycrystalline diamond-coated products that can be custom tailored for optical, electronic and engineering applications. Diamonex's initial focus is on optical products and the first commercial product is expected in late 1990. Other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools and bearings.

  2. Nanostructured Coatings

    NASA Astrophysics Data System (ADS)

    Rivière, J.-P.

    In many branches of technology where surfaces are playing a growing role, the use of coatings is often the only way to provide surfaces with specific functional properties. For example, the austenitic stainless steels or titanium alloys exhibit poor resistance to wear and low hardness values, which limits the field of applications. The idea then is to develop new solutions which would improve the mechanical performance and durability of objects used in contact and subjected to mechanical forces in hostile gaseous or liquid environments. Hard coatings are generally much sought after to enhance the resistance to wear and corrosion. They are of particular importance because they constitute a class of protective coatings which is already widely used on an industrial scale to improve the hardness and lifetime of cutting tools.

  3. Protective Coatings

    NASA Technical Reports Server (NTRS)

    1980-01-01

    General Magnaplate Corporation's pharmaceutical machine is used in the industry for high speed pressing of pills and capsules. Machine is automatic system for molding glycerine suppositories. These machines are typical of many types of drug production and packaging equipment whose metal parts are treated with space spinoff coatings that promote general machine efficiency and contribute to compliance with stringent federal sanitation codes for pharmaceutical manufacture. Collectively known as "synergistic" coatings, these dry lubricants are bonded to a variety of metals to form an extremely hard slippery surface with long lasting self lubrication. The coatings offer multiple advantages; they cannot chip, peel or be rubbed off. They protect machine parts from corrosion and wear longer, lowering maintenance cost and reduce undesired heat caused by power-robbing friction.

  4. Gold Coating

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Epner Technology Inc. responded to a need from Goddard Space Flight Center for the ultimate in electroplated reflectivity needed for the Mars Global Surveyor Mars Orbiter Laser Altimeter (MOLA). Made of beryllium, the MOLA mirror was coated by Epner Technology Laser Gold process, specially improved for the project. Improved Laser Gold- coated reflectors have found use in an epitaxial reactor built for a large semiconductor manufacturer as well as the waveguide in Braun-Thermoscan tympanic thermometer and lasing cavities in various surgical instruments.

  5. Fabrication of micro hole array on the surface of CVD ZnS by scanning ultrafast pulse laser for antireflection

    NASA Astrophysics Data System (ADS)

    Li, Yangping; Zhang, Tianhui; Fan, Siling; Cheng, Guanghua

    2017-04-01

    Chemical vapor deposited (CVD) ZnS is a promising long-wave infrared (8-12 μm) window material. Yet antireflection is necessary since Fresnel reflection from its surface is high due to the high refractive index of ZnS. Sub-wavelength structured surface of micro hole array was fabricated on CVD ZnS by scanning ultrafast pulse laser ablation. The effects of beam profile, pulse width and beam power on the radius and morphology of the holes were studied. Gaussian beam can cause severe melted-resolidified layers around the hole, yet Bessel beam only resulted in thin ribbon around the hole. The picosecond Bessel laser is more suitable than femtosecond laser for ablating holes on ZnS. The radius of the holes increases with increasing the Bessel beam pulse width and the beam power. But larger power may cause circle grooves around the central holes. Ordered hole array was fabricated on single side of CVD ZnS and antireflection was realized.

  6. Modeling the absorption behavior of solar thermal collector coatings utilizing graded alpha-C:H/TiC layers.

    PubMed

    Gruber, D P; Engel, G; Sormann, H; Schüler, A; Papousek, W

    2009-03-10

    Wavelength selective coatings are of common use in order to enhance the efficiency of devices heated by radiation such as solar thermal collectors. The use of suitable materials and the optimization of coating layer thicknesses are advisable ways to maximize the absorption. Further improvement is achievable by embedding particles in certain layers in order to modify material properties. We focus on optimizing the absorption behavior of a solar collector setup using copper as substrate, a layer of amorphous hydrogenated carbon with embedded titanium carbide particles (a-C:H/TiC), and an antireflection coating of amorphous silicon dioxide (aSiO(2)). For the setup utilizing homogeneous particle distribution, a relative absorption of 90.98% was found, while inhomogeneous particle embedding yielded 98.29%. These results are particularly interesting since until now, absorption of more than 95% was found only by using embedded Cr but not by using the more biocompatible Ti.

  7. .beta.-silicon carbide protective coating and method for fabricating same

    DOEpatents

    Carey, Paul G.; Thompson, Jesse B.

    1994-01-01

    A polycrystalline beta-silicon carbide film or coating and method for forming same on components, such as the top of solar cells, to act as an extremely hard protective surface, and as an anti-reflective coating. This is achieved by DC magnetron co-sputtering of amorphous silicon and carbon to form a SiC thin film onto a surface, such as a solar cell. The thin film is then irradiated by a pulsed energy source, such as an excimer laser, to synthesize the poly- or .mu.c-SiC film on the surface and produce .beta.--SiC. While the method of this invention has primary application in solar cell manufacturing, it has application wherever there is a requirement for an extremely hard surface.

  8. [beta]-silicon carbide protective coating and method for fabricating same

    DOEpatents

    Carey, P.G.; Thompson, J.B.

    1994-11-01

    A polycrystalline beta-silicon carbide film or coating and method for forming same on components, such as the top of solar cells, to act as an extremely hard protective surface, and as an anti-reflective coating are disclosed. This is achieved by DC magnetron co-sputtering of amorphous silicon and carbon to form a SiC thin film onto a surface, such as a solar cell. The thin film is then irradiated by a pulsed energy source, such as an excimer laser, to synthesize the poly- or [mu]c-SiC film on the surface and produce [beta]-SiC. While the method of this invention has primary application in solar cell manufacturing, it has application wherever there is a requirement for an extremely hard surface. 3 figs.

  9. Low-cost fabrication of large area sub-wavelength anti-reflective structures on polymer film using a soft PUA mold.

    PubMed

    Zhang, Jie; Shen, Su; Dong, Xiao X; Chen, Lin S

    2014-01-27

    A soft lithographic approach using a modified polyurethane acrylate (PUA) mold for the fabrication of sub-wavelength antireflective structure on polymer film is reported. By introducing an intermediate transferring PUA mold generated by an anodized aluminum oxide membrane, there is no need either to heat nor to deposit metal as a seed layer. Therefore, the most costly and time-consuming master preparation step in the conventional process chain is not a necessity. The soft PUA mold provides a high resolution of 100 nm with an aspect ratio of 1.7 and a conformal contact with the substrate and reduces the pressure needed during the imprinting steps. It is numerically verified that the antireflective film with nanopores has a similar fascinating broadband antireflective effect compared with that of its complementary nanonipple one. In our experiment, the average transmission efficiency of the PET film with dual-side nanopores can be enhanced to 98.7% at normal incidence and 92.5% at an incident angle of 60° over a range of 400~800 nm of the spectrum. The proposed method is simple and cost-effective and the fabricated antireflective polymer film can be mounted on the surfaces of various optical devices for the reduction of Fresnel reflections.

  10. Nickel-oxide film as an AR coating of Si window for IR sensor packaging

    NASA Astrophysics Data System (ADS)

    Shim, Hyunbin; Kim, Dongsoo; Kang, Ingu; Kim, Jinkwan; Lee, Hee Chul

    2013-06-01

    An infrared (IR) transparent window is necessary for the IR sensor package. The most commonly used materials for IR transparent window are germanium (Ge) and silicon (Si). Ge has excellent optical properties but also the disadvantage of expensive price. Si has merits such as inexpensive cost and CMOS process compatibility but it has lower transmittance in the range of LWIR region than Ge. Therefore, an alternative anti-reflection (AR) coating is necessary to increase the transmittance of Si as an IR transparent window in the LWIR region. A simple single layer antireflection coating was newly designed on the silicon window for the infrared sensor package. Among the various materials, nickel oxide (NiO) was selected as an AR coating material due to its suitable optical properties and simple process. NiO film was deposited onto the double sided polished Si wafer by reactive rf sputtering with Ni target in an environment of Ar and O2 mixed gas. The thickness of the NiO film was determined by Essential Macleod simulation. FT-IR was used to measure the transmittance of the samples in the LWIR region. After the nickel oxide film was sputtered onto the double sides of the silicon wafer, the measured transmittance of the Si wafer was increased over 20% in the LWIR region compared with that of uncoated Si wafer. Additionally, annealing effect on the transmittance of NiO coated Si wafer was studied. By increasing the annealing temperature from 300° to 700°, an additional increase of transmittance was achieved.

  11. COATING METHOD

    DOEpatents

    Townsend, R.G.

    1959-08-25

    A method is described for protectively coating beryllium metal by etching the metal in an acid bath, immersing the etched beryllium in a solution of sodium zincate for a brief period of time, immersing the beryllium in concentrated nitric acid, immersing the beryhlium in a second solution of sodium zincate, electroplating a thin layer of copper over the beryllium, and finally electroplating a layer of chromium over the copper layer.

  12. Thermochromism of sputter-deposited vanadium oxyfluoride coatings

    SciTech Connect

    Khan, K.A.; Granqvist, C.G.

    1990-12-31

    Thermochromism offers interesting possibilities for controlling the radiative throughput through windows, as well as for numerous other applications. The purpose of this brief paper is to point at the potential and prospects of using sputter-deposited vanadium oxyfluoride coatings. A thermochromic coating, suitable for energy-efficient windows, is characterized by a transmittance which drops as the temperature goes above a certain comfort temperature.Thermochromism in VO{sub 2}-based materials is well known; it is connected with a reversible structural transition from a low-temperature monoclinic phase to a high-temperature phase with metallic-like properties. The metallic phase is characterized by a plasma wavelength at {approximately} 1 {mu}m. Hence it is possible to accomplish a temperature-dependent modulation of the near-infrared transmittance. In order to produce a practically useful window coating, the VO{sub 2}-based material must be processed suitably. The authors discuss how magnetron sputtering can be used for (potential) large-area deposition. Among the many alternative approaches for depressing the phase change temperature they note the replacement of oxygen by fluorine and the introduction of stress either from the substrate or from a suitable overlayer. The work reported here deals with fluorination through reactive sputter deposition. A key result, reported below, is that the fluorination leads to a significant decrease of the luminous absorptance. Finally, it may be that a practical window coating must invoke a three-layer design with a VO{sub 2}-based coating embedded between antireflecting dielectric layers; this latter point will not be pursued further here.

  13. Transparent and Dense Ladder-Like Alkylene-Bridged Polymethylsiloxane Coating with Enhanced Water Vapor Barrier Property.

    PubMed

    Zhang, Ce; Zhang, Cong; Cui, Xinmin; Sun, Jinghua; Ding, Ruimin; Zhang, Qinghua; Xu, Yao

    2015-10-14

    Organic-inorganic hybrid composites have been well-studied as water vapor barrier materials for their long diffusion length of water vapor in coatings which can be realized by improving the aspect ratio of inorganic components and regularity of nanostructure in coatings. In this paper, dense organic-inorganic hybrid coating based on ladder-like alkylene-bridged polymethylsiloxane (ABPMS) was successfully fabricated through the hydrosilylation reaction between polymethylhydrosiloxane and diene (1,5-hexadiene or 1,7-octadiene) in toluene under Pt/C catalysis. Its ladder-like structure was verified by 29Si magic angle spinning (MAS) NMR, 13C MAS NMR, and in-plane and out-of-plane glance-incident X-ray diffraction (GIXRD) techniques. Its corresponding coating showed excellent water vapor barrier ability for a typical water-soluble crystal, potassium dihydrogen phosphate (KDP). When treated in 50% relative humidity (RH) condition at 25 °C for 8 months, the ABPMS coating with 100 nm thickness displayed a very low transmittance loss of 1.6% compared with the high transmittance loss of 10% for uncoated KDP. Moreover, the ABPMS coating showed good ultraviolet radiation resistance, thermal stability, low mechanical property, and excellent compatibility with hydrophobic antireflective (AR) coatings.

  14. Large-area sol-gel optical coatings for the Megajoule Laser prototype

    NASA Astrophysics Data System (ADS)

    Pegon, Philippe M.; Germain, Chantal V.; Rorato, Yannick R.; Belleville, Philippe F.; Lavastre, Eric

    2004-02-01

    In the field of thin film coatings, sol-gel (SG) process is an alternative to the conventional Physical Vapor Deposition (PVD) techniques. Sol-gel process is particularly competitive on large-area or fragile substates by taking advantage of various liquid phase deposition techniques performed at room temperature and atmospheric pressure, coupled with the versatility of organo-metallic chemistry. Developed by the French Commission for Atomic Energy (CEA) since 1985 for its former high-power lasers generation, optimized sol-gel coatings proved also very resistant to laser energy. In 1998, THALES Angenieux (TAGX) was selected by CEA to provide all the sol-gel coatings dedicated to the French Laser MegaJoule (LMJ) prototype, named Ligne d'Integration Laser (LIL). In cooperation with Saint-Etienne Pole Optique et Vision (POV), TAGX initiated the building of a sol-gel technological platform (SGPF) aimed at demonstrating the feasibility of production of optical and functional coatings on large area substrates. A technology transfer was performed by CEA (Le Ripault) to TAGX focusing on the manufacture mainly of single-layer antireflective coatings (SLAR), but also of multi-layer AR-coatings and of multi-layered highly reflective (HR)-coatings. Since beginning of 2001 and using SGPF equipments, TAGX successfully coated within specificaitons and schedule most of the 300 optics required for LIL activation. After this 2 years 1/2 production campaign in pre-industrial conditions, we can now analyse the advantages of each deposition technique used, the repeatability of the several processes, and the performance of the various coatings.

  15. NICKEL COATED URANIUM ARTICLE

    DOEpatents

    Gray, A.G.

    1958-10-01

    Nickel coatings on uranium and various methods of obtaining such coatings are described. Specifically disclosed are such nickel or nickel alloy layers as barriers between uranium and aluminum- silicon, chromium, or copper coatings.

  16. Spectral reflectance data of a high temperature stable solar selective coating based on MoSi2–Si3N4

    PubMed Central

    Hernández-Pinilla, D.; Rodríguez-Palomo, A.; Álvarez-Fraga, L.; Céspedes, E.; Prieto, J.E.; Muñoz-Martín, A.; Prieto, C.

    2016-01-01

    Data of optical performance, thermal stability and ageing are given for solar selective coatings (SSC) based on a novel MoSi2–Si3N4 absorbing composite. SSC have been prepared as multilayer stacks formed by silver as metallic infrared reflector, a double layer composite and an antireflective layer (doi: 10.1016/j.solmat.2016.04.001 [1]). Spectroscopic reflectance data corresponding to the optical performance of samples after moderate vacuum annealing at temperatures up to 600 °C and after ageing test of more than 200 h with several heating–cooling cycles are shown here. PMID:27182544

  17. Corrosion resistant coating

    DOEpatents

    Wrobleski, Debra A.; Benicewicz, Brian C.; Thompson, Karen G.; Bryan, Coleman J.

    1997-01-01

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  18. Corrosion resistant coating

    DOEpatents

    Wrobleski, D.A.; Benicewicz, B.C.; Thompson, K.G.; Bryan, C.J.

    1997-08-19

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  19. The Chemistry of Coatings.

    ERIC Educational Resources Information Center

    Griffith, James R.

    1981-01-01

    The properties of natural and synthetic polymeric "coatings" are reviewed, including examples and uses of such coatings as cellulose nitrate lacquers (for automobile paints), polyethylene, and others. (JN)

  20. Growth of TiO2 anti-reflection layer on textured Si (100) wafer substrate by metal-organic chemical vapor deposition method.

    PubMed

    Nam, Sang-Hun; Choi, Jin-Woo; Cho, Sang-Jin; Kimt, Keun Soo; Boo, Jin-Hyo

    2011-08-01

    Recently anti-reflective films (AR) have been intensely studied. Particularly for textured silicon solar cells, the AR films can further reduce the reflection of the incident light through trapping the incident light into the cells. In this work, TiO2 anti-reflection films have been grown on the textured Si (100) substrate which is processed in two steps, and the films are deposited using metal-organic chemical vapor deposition (MOCVD) with a precursor of titanium tetra-isopropoxide (TTIP). The effect of the substrate texture and the growth conditions of TiO2 films on the reflectance has been investigated. Pyramid size of textured silicon had approximately 2-9 microm. A well-textured silicon surface can lower the reflectance to 10%. For more reduced reflection, TiO2 anti-reflection films on the textured silicon were deposited at 600 degrees C using titanium tetra-isopropoxide (TTIP) as a precursor by metal-organic chemical vapor deposition (MOCVD), and the deposited TiO2 layers were then treated by annealing for 2 h in air at 600 and 1000 degrees C, respectively. In this process, the treated samples by annealing showed anatase and rutile phases, respectively. The thickness of TiO2 films was about 75 +/- 5 nm. The reflectance at specific wavelength can be reduced to 3% in optimum layer.

  1. Research on the shape error from the Gaussian moth-eye antireflection microstructure elements made by the laser interference lithography technology

    NASA Astrophysics Data System (ADS)

    Dong, Tingting; Fu, Yuegang; Zhang, Lei; Chen, Chi

    2015-11-01

    The contour shape of the Gaussian moth-eye antireflection microstructure elements is relied on the manufacturing method, the laser interference lithography technology, also effecting its' reflectivity. This paper gives out the reflectance characteristics of the Gaussian moth-eye antireflection microstructure elements made on the monocrystalline silicon substrate at the mid-infrared with the method of RCWA. We analyzes the different influences on the reflectivity from the cycle, trench depth, wavelength and refractive index by the way of univariate. At last getting the result by MATLAB simulation: the reflectivity become least at the 1.7μm when the cycle between 1~3μm, about 0.05%; the largest reflectivity is about 14%, when the cycle is 1μm. Similarly, the trench depth has great influence on the reflectivity, the reflectance decreased and stabilized with growing of the trench depth. At the same time, the wavelength has influence on the reflectivity. These conclusions is beneficial to designing Gaussian moth-eye antireflection microstructure elements. The conclusion is got that when the angle of incidence different, the azimuth influences the reflectivity.

  2. Electrocurtain coating process for coating solar mirrors

    DOEpatents

    Kabagambe, Benjamin; Boyd, Donald W.; Buchanan, Michael J.; Kelly, Patrick; Kutilek, Luke A.; McCamy, James W.; McPheron, Douglas A.; Orosz, Gary R.; Limbacher, Raymond D.

    2013-10-15

    An electrically conductive protective coating or film is provided over the surface of a reflective coating of a solar mirror by flowing or directing a cation containing liquid and an anion containing liquid onto the conductive surface. The cation and the anion containing liquids are spaced from, and preferably out of contact with one another on the surface of the reflective coating as an electric current is moved through the anion containing liquid, the conductive surface between the liquids and the cation containing liquid to coat the conductive surface with the electrically conductive coating.

  3. A luminescent down-shifting and moth-eyed anti-reflective film for highly efficient photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Ghymn, Yong H.; Jung, Kinam; Shin, Myunghun; Ko, Hyungduk

    2015-11-01

    Adhesive polydimethylsiloxane (PDMS) films were developed to increase the performance of photovoltaic devices. The films combined two separate features of moth-eye patterns to reduce the reflection of incident light at the film surface and luminescent down-shifting (LDS) CdZnS/ZnS-core/shell quantum dots (QDs) to convert ultraviolet (UV) radiation into visible light at 445 nm. The films were both flexible and self-adhesive, easily attachable to any surface of a solar cell module. By simply attaching the developed films on high-efficiency GaAs solar cells, the short circuit current density and power conversion efficiency of the solar cells increased to 33.8 mA cm-2 and 28.7%, by 1.1 mA cm-2 and 0.9 percentage points in absolute values, respectively. We showed that the enhancement of the GaAs solar cells was attributed to both the anti-reflection (AR) properties of the moth-eye patterns and the LDS of QDs using a scattering matrix method and external quantum efficiency measurements. The developed films are versatile in application for solar cells, and expected to aid in overcoming limits of material absorption and device structures.Adhesive polydimethylsiloxane (PDMS) films were developed to increase the performance of photovoltaic devices. The films combined two separate features of moth-eye patterns to reduce the reflection of incident light at the film surface and luminescent down-shifting (LDS) CdZnS/ZnS-core/shell quantum dots (QDs) to convert ultraviolet (UV) radiation into visible light at 445 nm. The films were both flexible and self-adhesive, easily attachable to any surface of a solar cell module. By simply attaching the developed films on high-efficiency GaAs solar cells, the short circuit current density and power conversion efficiency of the solar cells increased to 33.8 mA cm-2 and 28.7%, by 1.1 mA cm-2 and 0.9 percentage points in absolute values, respectively. We showed that the enhancement of the GaAs solar cells was attributed to both the anti-reflection

  4. Losses in TiO2/SiO2 multilayer coatings

    NASA Astrophysics Data System (ADS)

    Budasz, Jiří; Hutka, Jan; Václavík, Jan

    2016-11-01

    This paper deals with optical losses in the coatings consisting of a combination of titanium dioxide (TiO2) and silicon dioxide (SiO2) layers evaporated by the ion beam assisted deposition (IBAD). This combination is commonly used for optical coatings as a standard choice for antireflective or any other optical filter in the visible and near IR range. Although the technology has been known for decades, we point out that some undescribed parasite losses can still appear and we show how to deal with them. In fact, in some cases, the losses made the target coating even inapplicable. In this paper we try to investigate the origin of the losses and we describe the deposition parameters which allow us to reduce or completely remove them. We determined whether the losses are proportional to the total thickness of the coating or to the number of layers. The influence of scattering was measured as well. Deposition parameters which were studied are the substrate temperature, discharge voltage of the assisting ion gun, oxygen flow of the assisting ion gun and the deposition rate, especially its starting curve. Influence of the post process annealing was studied as well. Starting curve of the deposition rate of SiO2 layer and the amount of oxygen flowing through the assisting ion gun were found as a crucial parameters.

  5. Nanometre optical coatings based on strong interference effects in highly absorbing media.

    PubMed

    Kats, Mikhail A; Blanchard, Romain; Genevet, Patrice; Capasso, Federico

    2013-01-01

    Optical coatings, which consist of one or more films of dielectric or metallic materials, are widely used in applications ranging from mirrors to eyeglasses and photography lenses. Many conventional dielectric coatings rely on Fabry-Perot-type interference, involving multiple optical passes through transparent layers with thicknesses of the order of the wavelength to achieve functionalities such as anti-reflection, high-reflection and dichroism. Highly absorbing dielectrics are typically not used because it is generally accepted that light propagation through such media destroys interference effects. We show that under appropriate conditions interference can instead persist in ultrathin, highly absorbing films of a few to tens of nanometres in thickness, and demonstrate a new type of optical coating comprising such a film on a metallic substrate, which selectively absorbs various frequency ranges of the incident light. These coatings have a low sensitivity to the angle of incidence and require minimal amounts of absorbing material that can be as thin as 5-20 nm for visible light. This technology has the potential for a variety of applications from ultrathin photodetectors and solar cells to optical filters, to labelling, and even the visual arts and jewellery.

  6. Laser damage of HR, AR-coatings, monolayers and bare surfaces at 1064 nm

    NASA Technical Reports Server (NTRS)

    Garnov, S. V.; Klimentov, S. M.; Said, A. A.; Soileau, M. J.

    1993-01-01

    Laser induced damage thresholds and morphologies were investigated in a variety of uncoated and coated surfaces, including monolayers and multi-layers of different chemical compositions. Both antireflective (AR) and highly reflective (HR) were tested. Testing was done at 1064 nm with 25 picosecond and 8 nanosecond YAG/Nd laser single pulses. Spot diameter in the experiments varied from 0.09 to 0.22 mm. The laser damage measurement procedure consisted of 1-on-1 (single laser pulse in the selected site) and N-on-1 experiments including repeated irradiation by pulses of the same fluence and subsequently raised from pulse to pulse fluence until damage occurred. The highest picosecond damage thresholds of commercially available coatings averaged 12 - 14 J/sq cm, 50 percent less than thresholds obtained in bare fused silica. Some coatings and bare surfaces revealed a palpable preconditioning effect (an increase in threshold of 1.2 to 1.8 times). Picosecond and nanosecond data were compared to draw conclusions about pulse width dependence. An attempt was made to classify damage morphologies according to the type of coating, class of irradiating, and damage level.

  7. Development of low-absorption AR coatings for CO2 laser by ion assisted deposition

    NASA Astrophysics Data System (ADS)

    Iwamoto, Hiromi; Ebata, Keiji; Nanba, Hirokuni

    2003-02-01

    We have developed an anti-reflection (AR) coating technique designed for high power carbon dioxide (CO2) lasers that has low absorption and high resistance to humidity. This was achieved by performing ion-assisted deposition (IAD) using a Xe ion beam to apply BaF2 and ZnSe used as coating materials with extremely low bulk absorption coefficients. It was found that to achieve highly compact BaF2 thin films with low absorption on polycrystalline ZnSe substrates, both a surface flatness treatment using Xe ion bombardment and an optimized IAD condition of relatively low ion energy up to 200 eV are required. The absorption of the new (BaF2/ZnSe) AR coated ZnSe lens is 0.10 to 0.12%, approximately half that of conventional (ThF4/ZnSe) AR coated lenses. The new lens has both excellent anti-aging performance and a high resistance to humidity.

  8. Nanometre optical coatings based on strong interference effects in highly absorbing media

    NASA Astrophysics Data System (ADS)

    Kats, Mikhail A.; Blanchard, Romain; Genevet, Patrice; Capasso, Federico

    2013-01-01

    Optical coatings, which consist of one or more films of dielectric or metallic materials, are widely used in applications ranging from mirrors to eyeglasses and photography lenses. Many conventional dielectric coatings rely on Fabry-Perot-type interference, involving multiple optical passes through transparent layers with thicknesses of the order of the wavelength to achieve functionalities such as anti-reflection, high-reflection and dichroism. Highly absorbing dielectrics are typically not used because it is generally accepted that light propagation through such media destroys interference effects. We show that under appropriate conditions interference can instead persist in ultrathin, highly absorbing films of a few to tens of nanometres in thickness, and demonstrate a new type of optical coating comprising such a film on a metallic substrate, which selectively absorbs various frequency ranges of the incident light. These coatings have a low sensitivity to the angle of incidence and require minimal amounts of absorbing material that can be as thin as 5-20 nm for visible light. This technology has the potential for a variety of applications from ultrathin photodetectors and solar cells to optical filters, to labelling, and even the visual arts and jewellery.

  9. TiO2-Coated Carbon Nanotube-Silicon Solar Cells with Efficiency of 15%

    PubMed Central

    Shi, Enzheng; Zhang, Luhui; Li, Zhen; Li, Peixu; Shang, Yuanyuan; Jia, Yi; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Wu, Dehai; Zhang, Sen; Cao, Anyuan

    2012-01-01

    Combining carbon nanotubes (CNTs), graphene or conducting polymers with conventional silicon wafers leads to promising solar cell architectures with rapidly improved power conversion efficiency until recently. Here, we report CNT-Si junction solar cells with efficiencies reaching 15% by coating a TiO2 antireflection layer and doping CNTs with oxidative chemicals, under air mass (AM 1.5) illumination at a calibrated intensity of 100 mW/cm2 and an active device area of 15 mm2. The TiO2 layer significantly inhibits light reflectance from the Si surface, resulting in much enhanced short-circuit current (by 30%) and external quantum efficiency. Our method is simple, well-controlled, and very effective in boosting the performance of CNT-Si solar cells. PMID:23181192

  10. Non-antireflective scheme for efficiency enhancement of Cu(In,Ga)Se2 nanotip array solar cells.

    PubMed

    Liao, Yu-Kuang; Wang, Yi-Chung; Yen, Yu-Ting; Chen, Chia-Hsiang; Hsieh, Dan-Hua; Chen, Shih-Chen; Lee, Chia-Yu; Lai, Chih-Chung; Kuo, Wei-Chen; Juang, Jenh-Yi; Wu, Kaung-Hsiung; Cheng, Shun-Jen; Lai, Chih-Huang; Lai, Fang-I; Kuo, Shou-Yi; Kuo, Hao-Chung; Chueh, Yu-Lun

    2013-08-27

    We present systematic works in characterization of CIGS nanotip arrays (CIGS NTRs). CIGS NTRs are obtained by a one-step ion-milling process by a direct-sputtering process of CIGS thin films (CIGS TF) without a postselenization process. At the surface of CIGS NTRs, a region extending to 100 nm in depth with a lower copper concentration compared to that of CIGS TF has been discovered. After KCN washing, removal of secondary phases can be achieved and a layer with abundant copper vacancy (V(Cu)) was left. Such compositional changes can be a benefit for a CIGS solar cell by promoting formation of Cd-occupied Cu sites (Cd(Cu)) at the CdS/CIGS interface and creates a type-inversion layer to enhance interface passivation and carrier extraction. The raised V(Cu) concentration and enhanced Cd diffusion in CIGS NTRs have been verified by energy dispersive spectrometry. Strengthened adhesion of Al:ZnO (AZO) thin film on CIGS NTRs capped with CdS has also been observed in SEM images and can explain the suppressed series resistance of the device with CIGS NTRs. Those improvements in electrical characteristics are the main factors for efficiency enhancement rather than antireflection.

  11. Large Area Fabrication of Moth-Eye Antireflection Structures Using Self-Assembled Nanoparticles in Combination with Nanoimprinting

    NASA Astrophysics Data System (ADS)

    Tsutomu Nakanishi,; Toshiro Hiraoka,; Akira Fujimoto,; Takeshi Okino,; Shinobu Sugimura,; Takuya Shimada,; Koji Asakawa,

    2010-07-01

    A moth-eye structure, which suppresses the reflection on a surface, was fabricated on the entire surface of a large silicon wafer by the formation of a self-assembled particle monolayer as a dry-etch mask formed by our embedded particle monolayer (EPM) method. We optimized the shape of moth-eye structures by optical calculation and improved the fabrication procedure to allow formation over a large area. As a result, we succeeded in fabricating a moth-eye structure on the entire surface of a 12-in. silicon wafer and the surface reflectance was reduced to less than 0.8% in the visible light range. A large nickel mold, which is able to transfer the pattern to an 8-in. display, could be formed using the 12-in. silicon substrate as a master. A moth-eye film was fabricated by UV nanoimprinting using the nickel mold and the high antireflection performance was confirmed. The fabrication cost of the moth-eye structure over a large area would be markedly reduced by the use of the self-assembly technique in combination with nanoimprinting.

  12. Optimization and continuous fabrication of moth-eye nanostructure array on flexible polyethylene terephthalate substrate towards broadband antireflection.

    PubMed

    Zhang, Chengpeng; Yi, Peiyun; Peng, Linfa; Ni, Jun

    2017-04-01

    Reflection loss can cause harmful effects on the performance of optoelectronic devices, such as cell phones, notebooks, displays, solar cells, and light-emitting diode (LED) devices. In order to obtain broadband antireflection (AR) properties, many researchers have utilized surface texture techniques to produce AR subwavelength structures on the interfaces. Among the AR subwavelength structures, the moth-eye nanostructure is one of the most promising structures, with the potential for commercialization in the near future. In this research, to obtain broadband AR performance, the optimization of moth-eye nanostructures was first carried out using the finite difference time domain method within the spectral ranges of 400-800 nm, including the optimization of shape, height, pitch, and residual layer thickness. In addition, the continuous production of moth-eye nanostructure array upon a flexible polyethylene terephthalate substrate was demonstrated by using the roll-to-roll ultraviolet nanoimprint lithography (R2R UV-NIL) process and anodic aluminum oxide mold, which provided a solution for the cost-effective fabrication of moth-eye nanostructure array. The AR performance of moth-eye nanostructure array obtained by the R2R UV-NIL process was also investigated experimentally, and good consistence was shown with the simulated results. This research can provide a beneficial direction for the optimization and cost-effective production of the moth-eye nanostructure array.

  13. An antireflection transparent conductor with ultralow optical loss (<2 %) and electrical resistance (<6 Ω sq−1)

    PubMed Central

    Maniyara, Rinu Abraham; Mkhitaryan, Vahagn K.; Chen, Tong Lai; Ghosh, Dhriti Sundar; Pruneri, Valerio

    2016-01-01

    Transparent conductors are essential in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and solar cells. Here we demonstrate a transparent conductor with optical loss of ∼1.6%, that is, even lower than that of single-layer graphene (2.3%), and transmission higher than 98% over the visible wavelength range. This was possible by an optimized antireflection design consisting in applying Al-doped ZnO and TiO2 layers with precise thicknesses to a highly conductive Ag ultrathin film. The proposed multilayer structure also possesses a low electrical resistance (5.75 Ω sq−1), a figure of merit four times larger than that of indium tin oxide, the most widely used transparent conductor today, and, contrary to it, is mechanically flexible and room temperature deposited. To assess the application potentials, transparent shielding of radiofrequency and microwave interference signals with ∼30 dB attenuation up to 18 GHz was achieved. PMID:27991517

  14. An antireflection transparent conductor with ultralow optical loss (<2 %) and electrical resistance (<6 Ω sq(-1)).

    PubMed

    Maniyara, Rinu Abraham; Mkhitaryan, Vahagn K; Chen, Tong Lai; Ghosh, Dhriti Sundar; Pruneri, Valerio

    2016-12-19

    Transparent conductors are essential in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and solar cells. Here we demonstrate a transparent conductor with optical loss of ∼1.6%, that is, even lower than that of single-layer graphene (2.3%), and transmission higher than 98% over the visible wavelength range. This was possible by an optimized antireflection design consisting in applying Al-doped ZnO and TiO2 layers with precise thicknesses to a highly conductive Ag ultrathin film. The proposed multilayer structure also possesses a low electrical resistance (5.75 Ω sq(-1)), a figure of merit four times larger than that of indium tin oxide, the most widely used transparent conductor today, and, contrary to it, is mechanically flexible and room temperature deposited. To assess the application potentials, transparent shielding of radiofrequency and microwave interference signals with ∼30 dB attenuation up to 18 GHz was achieved.

  15. A luminescent down-shifting and moth-eyed anti-reflective film for highly efficient photovoltaic devices.

    PubMed

    Ghymn, Yong H; Jung, Kinam; Shin, Myunghun; Ko, Hyungduk

    2015-11-28

    Adhesive polydimethylsiloxane (PDMS) films were developed to increase the performance of photovoltaic devices. The films combined two separate features of moth-eye patterns to reduce the reflection of incident light at the film surface and luminescent down-shifting (LDS) CdZnS/ZnS-core/shell quantum dots (QDs) to convert ultraviolet (UV) radiation into visible light at 445 nm. The films were both flexible and self-adhesive, easily attachable to any surface of a solar cell module. By simply attaching the developed films on high-efficiency GaAs solar cells, the short circuit current density and power conversion efficiency of the solar cells increased to 33.8 mA cm(-2) and 28.7%, by 1.1 mA cm(-2) and 0.9 percentage points in absolute values, respectively. We showed that the enhancement of the GaAs solar cells was attributed to both the anti-reflection (AR) properties of the moth-eye patterns and the LDS of QDs using a scattering matrix method and external quantum efficiency measurements. The developed films are versatile in application for solar cells, and expected to aid in overcoming limits of material absorption and device structures.

  16. Flow coating apparatus and method of coating

    SciTech Connect

    Hanumanthu, Ramasubrahmaniam; Neyman, Patrick; MacDonald, Niles; Brophy, Brenor; Kopczynski, Kevin; Nair, Wood

    2014-03-11

    Disclosed is a flow coating apparatus, comprising a slot that can dispense a coating material in an approximately uniform manner along a distribution blade that increases uniformity by means of surface tension and transfers the uniform flow of coating material onto an inclined substrate such as for example glass, solar panels, windows or part of an electronic display. Also disclosed is a method of flow coating a substrate using the apparatus such that the substrate is positioned correctly relative to the distribution blade, a pre-wetting step is completed where both the blade and substrate are completed wetted with a pre-wet solution prior to dispensing of the coating material onto the distribution blade from the slot and hence onto the substrate. Thereafter the substrate is removed from the distribution blade and allowed to dry, thereby forming a coating.

  17. Apparatus for coating powders

    DOEpatents

    Makowiecki, Daniel M.; Kerns, John A.; Alford, Craig S.; McKernan, Mark A.

    2000-01-01

    A process and apparatus for coating small particles and fibers. The process involves agitation by vibrating or tumbling the particles or fibers to promote coating uniformly, removing adsorbed gases and static charges from the particles or fibers by an initial plasma cleaning, and coating the particles or fibers with one or more coatings, a first coating being an adhesion coating, and with subsequent coatings being deposited in-situ to prevent contamination at layer interfaces. The first coating is of an adhesion forming element (i.e. W, Zr, Re, Cr, Ti) of a 100-10,000 .ANG. thickness and the second coating or final coating of a multiple (0.1-10 microns) being Cu or Ag, for example for brazing processes, or other desired materials that defines the new surface related properties of the particles. An essential feature of the coating process is the capability to deposit in-situ without interruption to prevent the formation of a contaminated interface that could adversely affect the coating adhesion. The process may include screening of the material to be coated and either continuous or intermittent vibration to prevent agglomeration of the material to be coated.

  18. Hydro-oleophobic silica antireflective films with high laser-damage threshold

    NASA Astrophysics Data System (ADS)

    Yan, Lianghong; Lv, Haibing; Wang, Chengcheng; Yuan, Xiaodong

    2011-02-01

    A simple method of preparing hydro-oleophobic anitreflective films with high laser-damage threshold is reported in this article. By adding fluoroalkylsilanes (FAS) into reactant mixture as a co-precursor, FAS modified SiO 2 was obtained under base catalyzed hydrolysis and condensation of tetraethoxysilane. The dip-coating films were deposited on two sides of fused silica substrates. The experimental results on the effect of adding fluoroalkylsilanes (FAS) as a co-precursor on the hydro-oleophobicity and optical properties of tetraethoxysilane (TEOS) based silica AR films, are reported. The hydro-oleophobicity of the films was tested by the contact angle measurements and the highest water contact angle of 136° and oil (peanut) contact angle of 93° were obtained. The surface chemical modification of the hydro-oleophobic films was confirmed using Fourier transform infrared spectroscopy (FTIR). For the films based on FAS and TEOS, additional absorption bands at 1100 cm -1 corresponding to C-F bond presented, clearly indicating the organic modification of the films. The highest optical transmittance of the hydro-oleophobic films was found to be 99.5%. By a Nd:YAG lasers the laser-damage threshold of as-deposited films was measured at 351 nm wavelength (1 ns). The laser-damage threshold was as high as 22.6 J/cm 2.

  19. SiC protective coating for photovoltaic retinal prosthesis

    NASA Astrophysics Data System (ADS)

    Lei, Xin; Kane, Sheryl; Cogan, Stuart; Lorach, Henri; Galambos, Ludwig; Huie, Philip; Mathieson, Keith; Kamins, Theodore; Harris, James; Palanker, Daniel

    2016-08-01

    Objective. To evaluate plasma-enhanced, chemically vapor deposited (PECVD) amorphous silicon carbide (α-SiC:H) as a protective coating for retinal prostheses and other implantable devices, and to study their failure mechanisms in vivo. Approach. Retinal prostheses were implanted in rats sub-retinally for up to 1 year. Degradation of implants was characterized by optical and scanning electron microscopy. Dissolution rates of SiC, SiN x and thermal SiO2 were measured in accelerated soaking tests in saline at 87 °C. Defects in SiC films were revealed and analyzed by selectively removing the materials underneath those defects. Main results. At 87 °C SiN x dissolved at 18.3 ± 0.3 nm d-1, while SiO2 grown at high temperature (1000 °C) dissolved at 0.104 ± 0.008 nm d-1. SiC films demonstrated the best stability, with no quantifiable change after 112 d. Defects in thin SiC films appeared primarily over complicated topography and rough surfaces. Significance. SiC coatings demonstrating no erosion in accelerated aging test for 112 d at 87 °C, equivalent to about 10 years in vivo, can offer effective protection of the implants. Photovoltaic retinal prostheses with PECVD SiC coatings exhibited effective protection from erosion during the 4 month follow-up in vivo. The optimal thickness of SiC layers is about 560 nm, as defined by anti-reflective properties and by sufficient coverage to eliminate defects.

  20. How smooth chemistry allows high-power laser optical coating preparation

    NASA Astrophysics Data System (ADS)

    Belleville, Philippe F.; Prene, Philippe; Bonnin, Claude; Beaurain, Laurence; Montouillout, Yves; Lavastre, Eric

    2004-02-01

    For fifty years, a considerable effort has been and is still being directed to the production of optical coatings using liquid deposition route. Sol-Gel is a chemical process widely used for oxide material preparation. Based on smooth chemistry (low temperature conditions), sol-gel allows nanoparticle and polymeric material synthesis dispersed in appropriate liquid medium. The process investigated at CEA (French Commission for Atomic Energy) is strongly developed to afford coatings onto mineral or metallic substrates using colloidal oxide-based and/or inorganic-organic hybrid materials. Such a chemical process is sufficiently adjustable to develop purpose-built materials and coatings for high power laser optical components, taking into account the high laser damage threshold requirement. Because the CEA megajoule-class pulsed laser is needing 7,000-m2 of coated area onto 10,000 large-sized optical components, we have developed to date, several optical coating procedures, each optical thin film being prepared from a specific material and deposition process. First need to fulfil was the antireflective (AR) coating required for transparent optics and used to increase laser light transmission and to suppress damaging residual reflection. The as-developed AR-coatings were made of nanosized particle-containing fragile single layer or abrasion-resistant polymeric-based broadband layer stack. For used on highly-reflective (HR) component, a specific unstressed multilayer coating has been developed and deposited onto deformable adaptative end-cavity mirror substrate. This HR-coating is made of quaterwave stack of colloidal-based low index and hybrid high index thin films. Using such materials, first high ratio polarizing sol-gel coatings have been also produced. Apart optical coating preparation, sol-gel chemistry has been used to develop an hybrid dense protective thin film to enhance durability of oxidation-sensitive silver cavity reflectors. Each coating material

  1. Improved Polyimide Intumescent Coating

    NASA Technical Reports Server (NTRS)

    Salyer, I. O.; Fox, L. B.

    1984-01-01

    New polyimide intumescent coating uses titanium dioxide and glass microballons as nucleating agents to improve foaming characteristics of commercially-available polyimide precursor resin. Used for coating interior surfaces in commercial aircraft.

  2. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S. (Inventor)

    1984-01-01

    A high temperature oxidation resistant, thermal barrier coating system is disclosed for a nickel cobalt, or iron base alloy substrate. An inner metal bond coating contacts the substrate, and a thermal barrier coating covers the bond coating. NiCrAlR, FeCrAlR, and CoCrAlR alloys are satisfactory as bond coating compositions where R=Y or Yb. These alloys contain, by weight, 24.9-36.7% chromium, 5.4-18.5% aluminum, and 0.05 to 1.55% yttrium or 0.05 to 0.53% ytterbium. The coatings containing ytterbium are preferred over those containing yttrium. An outer thermal barrier coating of partial stabilized zirconium oxide (zirconia) which is between 6% and 8%, by weight, of yttrium oxide (yttria) covers the bond coating. Partial stabilization provides a material with superior durability. Partially stabilized zirconia consists of mixtures of cubic, tetragonal, and monoclinic phases.

  3. Coating Galvanized Steel

    DTIC Science & Technology

    1989-06-01

    phenolic drying oil products with a zinc dust-zinc oxide pigmentation. Roebuck et al. (Ref 3), state "For instance, coatings subject to saponification ...coating. All three types of TT-P-641 are subject to saponification , since they con- tain drying oils. The General Services Administration (GSA) sells con...penetration " Chemical degradation of coatings, particularly saponification of alkyd coatings in an alkaline environment " Differences in expansion and

  4. METHOD FOR TESTING COATINGS

    DOEpatents

    Johns, I.B.; Newton, A.S.

    1958-09-01

    A method is described for detecting pin hole imperfections in coatings on uranium-metal objects. Such coated objects are contacted with a heated atmosphere of gaseous hydrogen and imperfections present in the coatings will allow the uranlum to react with the hydrogen to form uranium hydride. Since uranium hydride is less dense than uranium metal it will swell, causing enlargement of the coating defeot and rendering it visible.

  5. Characterization of RSI coating

    NASA Technical Reports Server (NTRS)

    Miller, A. D.; Garofalini, S. H.; Smiser, L. W.; Mueller, J. I.

    1973-01-01

    X-ray diffraction analyses on mullite, silica, and ceramic mullite fiber coating materials to investigate the effects of thermal cycling, show that ceramic mullite fiber coating porosity is little affected by cycling to 1250 C and that material pores are mostly smaller than 15 nm. Some mullite coatings experience a slight increase in crystobalite with somewhat increased porosity. Silica coatings show a marked tendency to precipitate cristobalite with increased porosity and dimensional instability.

  6. Peculiarities of the capacitance-voltage characteristic of a photoelectric solar energy convertor based on a silicon p- n junction with a porous silicon antireflection coating

    NASA Astrophysics Data System (ADS)

    Tregulov, V. V.

    2014-09-01

    Experimental results on the high-frequency capacitance-voltage characteristic of a photoelectric solar energy converter based on the n +- p junction with a thin porous silicon film on the frontal surface are considered. It is shown that the capacitance-voltage characteristic is determined by the surface metal-insulator-semiconductor (MIS) structure formed as a result of growing of a porous silicon layer by electrochemical anode etching. The effective thickness of the insulator layer of the MIS structure, the impurity concentration in its semiconductor region, and the density of surface states are determined.

  7. Antireflective coating for AgBr-TlI and AgBr-TlBr0.46I0.54 solid solution crystals

    NASA Astrophysics Data System (ADS)

    Korsakov, Alexandr; Salimgareev, Dmitrii; Lvov, Alexandr; Zhukova, Liya

    2016-12-01

    We researched the process of ultraviolet (UV) irradiation for the crystals of AgBr-TlI and AgBr-TlBr0.46I0.54 systems. It was found that on the surface of irradiated crystals, the film is formed and film grain size depends on exposure time and crystal composition. This film proved to gain the transmission by reducing the reflection from its surface within the 8.0-27.0 μm range.

  8. PIT Coating Requirements Analysis

    SciTech Connect

    MINTEER, D.J.

    2000-10-20

    This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products.

  9. Nanostructured Protective Coatings

    DTIC Science & Technology

    2006-01-01

    potential superior wear resistance properties. The Nanostructured Protective Coatings (NPC) program was designed to establish a collaborative team of...understanding of PVD parameters, depositing coatings on practical substrates such as the Ti6Al4V used for turbine blades , and developing a versatile...Nanostructured Protective Coatings (NPC) program was designed to establish a collaborative team of three entities (Pennsylvania State University

  10. Spin coating of electrolytes

    DOEpatents

    Stetter, Joseph R.; Maclay, G. Jordan

    1989-01-01

    Methods for spin coating electrolytic materials onto substrates are disclosed. More particularly, methods for depositing solid coatings of ion-conducting material onto planar substrates and onto electrodes are disclosed. These spin coating methods are employed to fabricate electrochemical sensors for use in measuring, detecting and quantifying gases and liquids.

  11. Ceramic with zircon coating

    NASA Technical Reports Server (NTRS)

    Wang, Hongyu (Inventor)

    2003-01-01

    An article comprises a silicon-containing substrate and a zircon coating. The article can comprise a silicon carbide/silicon (SiC/Si) substrate, a zircon (ZrSiO.sub.4) intermediate coating and an external environmental/thermal barrier coating.

  12. Commercial Fastener Coatings Doerken

    DTIC Science & Technology

    2010-06-01

    Phosphating* *partly recommended Dip Spinning Dipping Spraying Spin coating Conveyor oven box oven Inductive drying Pretreatment Coating Preheating...Curing Cooling Application Techniques - Dip Spin Coating Gurtbnd Cross BarTranspo" Band beiCifteiE Vo12one Vent llated Pre .Zone Cros~ Bar T ransrt

  13. Preparation and characterization of SiO₂:Sm³⁺ nanotube arrays with 1.06 μm laser antireflective property

    SciTech Connect

    Tan, Wei-min; Huang, Ning; Wang, Li-jun; Song, Tian-shun; Lu, Chun-hua; Wang, Liu-fang; Zhang, Jun-zhi

    2013-05-01

    SiO₂: Sm³⁺ nanotube arrays with excellent antireflective property at 1.06 μm were synthesized by a template-assisted sol–gel process. The molecular structure, morphology and optical properties of the fabricated SiO₂:Sm³⁺ nanotube arrays were investigated by a Fourier transform infrared spectroscope (FTIR), a Scanning electron microscope (SEM), and a spectro-fluorometer, respectively. The experimental results demonstrate that the SiO₂:Sm³⁺ nanotube arrays were formed via the AAO membrane during the sol–gel process. The remarkable antireflective characteristic of about 0.166% at 1.06 μm was attributed to the drastic decrease of effective refraction index which enhances the matching effect between air and substrate. As well as the absorption performance of Sm³⁺ at 1.06 μm which consumes the energies of incident light. - Graphical abstract: Directional aligned SiO₂:Sm³⁺ nanotube arrays were synthesized in AAO template by sol–gel process, and the antiflective performance of arrays is prominent comparing to the blank AAO template. Highlights: • SiO₂:Sm³⁺ nanotube arrays are synthesized by a template-assisted sol–gel process. • SiO₂:Sm³⁺ nanotube arrays have remarkable antireflective properties at 1.06 μm. • The subwavelength structure results in a decrease of effective refraction index. • The absorption performance of Sm³⁺ at 1.06 μm consume the energies of incident light.

  14. Biomimetic artificial Si compound eye surface structures with broadband and wide-angle antireflection properties for Si-based optoelectronic applications

    NASA Astrophysics Data System (ADS)

    Leem, Jung Woo; Song, Young Min; Yu, Jae Su

    2013-10-01

    We report the biomimetic artificial silicon (Si) compound eye structures for broadband and wide-angle antireflection by integrating nanostructures (NSs) into periodically patterned microstructures (p-MSs) via thermal dewetting of gold and subsequent dry etching. The truncated cone microstructures with a two-dimensional hexagonal symmetry pattern were fabricated by photolithography and dry etching processes. The desirable shape and density of the nanostructures were obtained by controlled dewetting. The incorporation of p-MSs into the NS/Si surface further reduced the surface total reflectance over a wide wavelength range of 300-1030 nm at near normal incidence, indicating the average reflectance (Ravg) and solar weighted reflectance (RSWR) values of ~2.5% and 2%, respectively, compared to the only NSs on the flat Si surface (i.e., Ravg ~ 4.9% and RSWR ~ 4.5%). Additionally, the resulting structure improved the angle-dependent antireflection property due to its relatively omnidirectional shape, which exhibited the Ravg < 4.3% and RSWR < 3.7% in the wavelength region of 300-1100 nm even at a high incident light angle of 70° in the specular reflectance.We report the biomimetic artificial silicon (Si) compound eye structures for broadband and wide-angle antireflection by integrating nanostructures (NSs) into periodically patterned microstructures (p-MSs) via thermal dewetting of gold and subsequent dry etching. The truncated cone microstructures with a two-dimensional hexagonal symmetry pattern were fabricated by photolithography and dry etching processes. The desirable shape and density of the nanostructures were obtained by controlled dewetting. The incorporation of p-MSs into the NS/Si surface further reduced the surface total reflectance over a wide wavelength range of 300-1030 nm at near normal incidence, indicating the average reflectance (Ravg) and solar weighted reflectance (RSWR) values of ~2.5% and 2%, respectively, compared to the only NSs on the flat Si

  15. Specific features of current flow mechanisms in the semiconductor structure of a photoelectric converter with an n +- p-junction and an antireflective porous silicon film

    NASA Astrophysics Data System (ADS)

    Tregulov, V. V.; Stepanov, V. A.; Litvinov, V. G.; Ermachikhin, A. V.

    2016-11-01

    The temperature dependence of forward and reverse branches of the current-voltage characteristic of the semiconductor structure of a photoelectric converter with an n +- p-junction based on single-crystal silicon and an antireflective porous silicon film on the front surface has been studied. The presence of several current flow mechanisms has been revealed. It has been demonstrated that traps that emerge in the process of the formation of the porous silicon film have a considerable effect on the current flow processes in the semiconductor structure under consideration.

  16. pH-Switchable Stratification of Colloidal Coatings: Surfaces "On Demand".

    PubMed

    Martín-Fabiani, Ignacio; Fortini, Andrea; Lesage de la Haye, Jennifer; Koh, Ming Liang; Taylor, Spencer E; Bourgeat-Lami, Elodie; Lansalot, Muriel; D'Agosto, Franck; Sear, Richard P; Keddie, Joseph L

    2016-12-21

    Stratified coatings are used to provide properties at a surface, such as hardness or refractive index, which are different from underlying layers. Although time-savings are offered by self-assembly approaches, there have been no methods yet reported to offer stratification on demand. Here, we demonstrate a strategy to create self-assembled stratified coatings, which can be switched to homogeneous structures when required. We use blends of large and small colloidal polymer particle dispersions in water that self-assemble during drying because of an osmotic pressure gradient that leads to a downward velocity of larger particles. Our confocal fluorescent microscopy images reveal a distinct surface layer created by the small particles. When the pH of the initial dispersion is raised, the hydrophilic shells of the small particles swell substantially, and the stratification is switched off. Brownian dynamics simulations explain the suppression of stratification when the small particles are swollen as a result of reduced particle mobility, a drop in the pressure gradient, and less time available before particle jamming. Our strategy paves the way for applications in antireflection films and protective coatings in which the required surface composition can be achieved on demand, simply by adjusting the pH prior to deposition.

  17. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Liquid, spray on elastomeric polyurethanes are selected and investigated as best candidates for aircraft external protective coatings. Flight tests are conducted to measure drag effects of these coatings compared to paints and a bare metal surface. The durability of two elastometric polyurethanes are assessed in airline flight service evaluations. Laboratory tests are performed to determine corrosion protection properties, compatibility with aircraft thermal anti-icing systems, the effect of coating thickness on erosion durability, and the erosion characteristics of composite leading edges-bare and coated. A cost and benefits assessment is made to determine the economic value of various coating configurations to the airlines.

  18. Antibacterial polymer coatings.

    SciTech Connect

    Wilson, Mollye C.; Allen, Ashley N.; Barnhart, Meghan; Tucker, Mark David; Hibbs, Michael R.

    2009-09-01

    A series of poly(sulfone)s with quaternary ammonium groups and another series with aldehyde groups are synthesized and tested for biocidal activity against vegetative bacteria and spores, respectively. The polymers are sprayed onto substrates as coatings which are then exposed to aqueous suspensions of organisms. The coatings are inherently biocidal and do not release any agents into the environment. The coatings adhere well to both glass and CARC-coated coupons and they exhibit significant biotoxicity. The most effective quaternary ammonium polymers kills 99.9% of both gram negative and gram positive bacteria and the best aldehyde coating kills 81% of the spores on its surface.

  19. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S.; Leibert, C. H. (Inventor)

    1977-01-01

    A coating system which contains a bond coating and a thermal barrier coating is applied to metal surfaces such as turbine blades and provides both low thermal conductivity and improved adherence when exposed to high temperature gases or liquids. The bond coating contains NiCrAlY and the thermal barrier coating contains a reflective oxide. The reflective oxides ZrO2-Y2O3 and ZrO2-MgO have demonstrated significant utility in high temperature turbine applications.

  20. Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    1993-01-01

    In order to reduce heat transfer between a hot gas heat source and a metallic engine component, a thermal insulating layer of material is placed between them. This thermal barrier coating is applied by plasma spray processing the thin films. The coating has been successfully employed in aerospace applications for many years. Lewis Research Center, a leader in the development engine components coating technology, has assisted Caterpillar, Inc. in applying ceramic thermal barrier coatings on engines. Because these large engines use heavy fuels containing vanadium, engine valve life is sharply decreased. The barrier coating controls temperatures, extends valve life and reduces operating cost. Additional applications are currently under development.

  1. Bacillus subtilis Spore Coat

    PubMed Central

    Driks, Adam

    1999-01-01

    In response to starvation, bacilli and clostridia undergo a specialized program of development that results in the production of a highly resistant dormant cell type known as the spore. A proteinacious shell, called the coat, encases the spore and plays a major role in spore survival. The coat is composed of over 25 polypeptide species, organized into several morphologically distinct layers. The mechanisms that guide coat assembly have been largely unknown until recently. We now know that proper formation of the coat relies on the genetic program that guides the synthesis of spore components during development as well as on morphogenetic proteins dedicated to coat assembly. Over 20 structural and morphogenetic genes have been cloned. In this review, we consider the contributions of the known coat and morphogenetic proteins to coat function and assembly. We present a model that describes how morphogenetic proteins direct coat assembly to the specific subcellular site of the nascent spore surface and how they establish the coat layers. We also discuss the importance of posttranslational processing of coat proteins in coat morphogenesis. Finally, we review some of the major outstanding questions in the field. PMID:10066829

  2. Coatings for directional eutectics

    NASA Technical Reports Server (NTRS)

    Rairden, J. R.; Jackson, M. R.

    1976-01-01

    Significant advances have been made in the development of an environmentally stable coating for a very high strength, directionally solidified eutectic alloy designated NiTaC-13. Three duplex (two-layer) coatings survived 3,000 hours on a cyclic oxidation test (1,100 C to 90 C). These coatings were fabricated by first depositing a layer of NiCrAl(Y) by vacuum evaporation from an electron beam heated source, followed by depositing an aluminizing overlayer. The alloy after exposure with these coatings was denuded of carbide fibers at the substrate/coating interface. It was demonstrated that TaC fiber denudation can be greatly retarded by applying a carbon-bearing coating. The coating was applied by thermal spraying followed by aluminization. Specimens coated with NiCrAlCY+Al survived over 2,000 hours in the cyclic oxidation test with essentially no TaC denudation. Coating ductility was studied for coated and heat-treated bars, and stress rupture life at 871 C and 1,100 C was determined for coated and cycled bars.

  3. Strain isolated ceramic coatings

    NASA Technical Reports Server (NTRS)

    Tolokan, R. P.; Brady, J. B.; Jarrabet, G. P.

    1985-01-01

    Plasma sprayed ceramic coatings are used in gas turbine engines to improve component temperature capability and cooling air efficiency. A compliant metal fiber strain isolator between a plasma sprayed ceramic coating and a metal substrate improves ceramic durability while allowing thicker coatings for better insulation. Development of strain isolated coatings has concentrated on design and fabrication of coatings and coating evaluation via thermal shock testing. In thermal shock testing, five types of failure are possible: buckling failure im compression on heat up, bimetal type failure, isothermal expansion mismatch failure, mudflat cracking during cool down, and long term fatigue. A primary failure mode for thermally cycled coatings is designated bimetal type failure. Bimetal failure is tensile failure in the ceramic near the ceramic-metal interface. One of the significant benefits of the strain isolator is an insulating layer protecting the metal substrate from heat deformation and thereby preventing bimetal type failure.

  4. Coated Aerogel Beads

    NASA Technical Reports Server (NTRS)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2014-01-01

    Methods and apparatus for coating particulate material are provided. The apparatus includes a vessel having a top and a bottom, a vertically extending conduit having an inlet in the vessel and an outlet outside of the vessel, a first fluid inlet in the bottom of the vessel for introducing a transfer fluid, a second fluid inlet in the bottom of the vessel for introducing a coating fluid, and a fluid outlet from the vessel. The method includes steps of agitating a material, contacting the material with a coating material, and drying the coating material to produce a coated material. The invention may be adapted to coat aerogel beads, among other materials. A coated aerogel bead and an aerogel-based insulation material are also disclosed.

  5. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    SciTech Connect

    Hampikian, J.M.; Carter, W.B.

    1995-10-01

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  6. 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.

  7. Broadband wide-angle antireflection enhancement in AZO/Si shell/core subwavelength grating structures with hydrophobic surface for Si-based solar cells.

    PubMed

    Leem, Jung Woo; Song, Young Min; Yu, Jae Su

    2011-09-12

    Broadband wide-angle antireflection characteristics of aluminum-doped zinc oxide (AZO)/silicon (Si) shell/core subwavelength grating (SWG) structures with a hydrophobic surface, together with theoretical prediction using a rigorous coupled-wave analysis simulation, were investigated for Si-based solar cells. The AZO films with different thicknesses were deposited on Si SWGs by rf magnetron sputtering method, which forms a shell/core structure. The AZO/Si shell/core SWGs reduced significantly the surface reflection compared to the AZO films/Si substrate. The coverage of AZO films on Si SWGs improved the antireflective property over a wider incident angle. The AZO/Si shell/core SWG structure with a 200 nm-thick AZO layer deposited at an rf power of 200 W exhibited a water contact angle of 123°. This structure also exhibited a low average reflectance of ~2% over a wide wavelength range of 300-2100 nm with a solar weighted reflectance of 2.8%, maintaining a reflectance of < 9.2% at wavelengths of 300-2100 nm up to the incident angle of θ(i) = 70°. The effective electrical properties of AZO films in AZO/Si shell/core SWGs were also analyzed.

  8. Tailored coatings for hardfacing

    SciTech Connect

    Dustoor, M.R.; Moskowitz, L.N.

    1984-01-01

    An update on Conforma Clad coatings, first presented at the 1982 National Powder Metallurgy Conference in Montreal, Canada, is presented. The major advantage is the ability to offer selective-area coatings in a wide range of thicknesses and material choices while retaining dimensional and edge control of the coating. Complex geometries can be coated with a high materials utilization and with coating properties tailored to the end application. Porosity and bond strength values can match or exceed those seen with the best commercially available thermal sprayed coatings. The ability of the process to balance abrasion resistance and toughness requirements for a specific wear mode, is illustrated by microstructural control of the size, shape and density of carbide particles contained in the coatings. Dry sand abrasive test data are provided on Conforma Clad coatings and competitive processes. Ongoing developments of non-furnace fusion techniques, such as laser cladding, are presented and the microstructures compared with those obtained with conventional coating processes. Commercial applications for these coatings are highlighted with some typical examples.

  9. Development of technique for AR coating and nickel and copper metallization of solar cells. FPS Project: Product development

    NASA Technical Reports Server (NTRS)

    Taylor, W.

    1982-01-01

    Printed nickel overplated with copper and applied on top of a predeposited silicon nitride antireflective coating system for metallizing solar cells was analyzed. The ESL D and E paste formulations, and the new formulations F, G, H, and D-1 were evaluated. The nickel thick films were tested after firing for stability in the cleaning and plating solutions used in the Vanguard-Pacific brush plating process. It was found that the films are very sensitive to the leaning and alkaline copper solutions. Less sensitivity was displayed to the neutral copper solution. Microscopic and SEM observations show segregation of frit at the silicon nitride thick film interface with loose frit residues after lifting off plated grid lines.

  10. Coatings for graphite fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Graphite fibers released from composites during burning or an explosion caused shorting of electrical and electronic equipment. Silicon carbide, silica, silicon nitride and boron nitride were coated on graphite fibers to increase their electrical resistances. Resistances as high as three orders of magnitude higher than uncoated fiber were attained without any significant degradation of the substrate fiber. An organo-silicone approach to produce coated fibers with high electrical resistance was also used. Celion 6000 graphite fibers were coated with an organo-silicone compound, followed by hydrolysis and pyrolysis of the coating to a silica-like material. The shear and flexural strengths of composites made from high electrically resistant fibers were considerably lower than the shear and flexural strengths of composites made from the lower electrically resistant fibers. The lower shear strengths of the composites indicated that the coatings on these fibers were weaker than the coating on the fibers which were pyrolyzed at higher temperature.

  11. Electrospark deposition coatings

    NASA Astrophysics Data System (ADS)

    Sheely, W. F.

    1986-11-01

    Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or cermet can be deposited on conductive materials. Thickness is usually two mils or less, but can be as high as 10 mils. ESD coatings can quadrupole cutting tool life.

  12. Optical coating in space

    NASA Technical Reports Server (NTRS)

    Bunner, A. N.

    1983-01-01

    A technological appraisal of the steps required to approach the goal of in-situ optical coating, cleaning and re-coating the optical elements of a remote telescope in space is reported. Emphasis is placed on the high ultraviolet throughput that a telescope using bare aluminum mirrors would offer. A preliminary design is suggested for an Orbital Coating Laboratory to answer basic technical questions.

  13. Electrospark deposition coatings

    SciTech Connect

    Sheely, W.F.

    1986-11-19

    Hard surfacing for wear resistant and low-friction coatings has been improved by means of advances in the computer controls in electronic circuitry of the electrospark deposition (ESD) process. coatings of nearly any electrically conductive metal alloy or cermet can be deposited on conductive materials. Thickness is usually two mils or less, but can be as high as 10 mils. ESD coatings can quadrupole cutting tool life. (DLC)

  14. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  15. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  16. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, T.

    1997-02-18

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate {alpha}-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal. 33 figs.

  17. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, Toshifumi

    1997-01-01

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

  18. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A series of studies in which films and liquid spray-on materials were evaluated in the laboratory for transport aircraft external surface coatings are summarized. Elastomeric polyurethanes were found to best meet requirements. Two commercially available products, CAAPCO B-274 and Chemglaze M313, were subjected to further laboratory testing, airline service evaluations, and drag-measurement flight tests. It was found that these coatings were compatible with the severe operating environment of airlines and that coatings reduced airplane drag. An economic analysis indicated significant dollar benefits to airlines from application of the coatings.

  19. Coatings for Graphite Fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Several approaches for applying high resistance coatings continuously to graphite yarn were investigated. Two of the most promising approaches involved (1) chemically vapor depositing (CVD) SiC coatings on the surface of the fiber followed by oxidation, and (2) drawing the graphite yarn through an organo-silicone solution followed by heat treatments. In both methods, coated fibers were obtained which exhibited increased electrical resistances over untreated fibers and which were not degraded. This work was conducted in a previous program. In this program, the continuous CVD SiC coating process used on HTS fiber was extended to the coating of HMS, Celion 6000, Celion 12000 and T-300 graphite fiber. Electrical resistances three order of magnitude greater than the uncoated fiber were measured with no significant degradation of the fiber strength. Graphite fibers coated with CVD Si3N4 and BN had resistances greater than 10(exp 6) ohm/cm. Lower pyrolysis temperatures were used in preparing the silica-like coatings also resulting in resistances as high as three orders of magnitude higher than the uncoated fiber. The epoxy matrix composites prepared using these coated fibers had low shear strengths indicating that the coatings were weak.

  20. Oxide coating development

    SciTech Connect

    Stinton, D.P.

    1995-06-01

    Monolithic SiC heat exchangers and fiber-reinforced SiC-matrix composite heat exchangers and filters are susceptible to corrosion by alkali metals at elevated temperatures. Protective coatings are currently being developed to isolate the SiC materials from the corrodants. Unfortunately, these coatings typically crack and spall when applied to SiC substrates. The purpose of this task is to determine the feasibility of using a compliant material between the protective coating and the substrate. The low-modulus compliant layer could absorb stresses and eliminate cracking and spalling of the protective coatings.

  1. Combustion chemical vapor deposited coatings for thermal barrier coating systems

    SciTech Connect

    Hampikian, J.M.; Carter, W.B.

    1995-12-31

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings. In this report, the evaluation of alumina and ceria coatings on a nickel-chromium alloy is described.

  2. Al2O3/SiON stack layers for effective surface passivation and anti-reflection of high efficiency n-type c-Si solar cells

    NASA Astrophysics Data System (ADS)

    Thi Thanh Nguyen, Huong; Balaji, Nagarajan; Park, Cheolmin; Triet, Nguyen Minh; Le, Anh Huy Tuan; Lee, Seunghwan; Jeon, Minhan; Oh, Donhyun; Dao, Vinh Ai; Yi, Junsin

    2017-02-01

    Excellent surface passivation and anti-reflection properties of double-stack layers is a prerequisite for high efficiency of n-type c-Si solar cells. The high positive fixed charge (Q f) density of N-rich hydrogenated amorphous silicon nitride (a-SiNx:H) films plays a poor role in boron emitter passivation. The more the refractive index ( n ) of a-SiNx:H is decreased, the more the positive Q f of a-SiNx:H is increased. Hydrogenated amorphous silicon oxynitride (SiON) films possess the properties of amorphous silicon oxide (a-SiOx) and a-SiNx:H with variable n and less positive Q f compared with a-SiNx:H. In this study, we investigated the passivation and anti-reflection properties of Al2O3/SiON stacks. Initially, a SiON layer was deposited by plasma enhanced chemical vapor deposition with variable n and its chemical composition was analyzed by Fourier transform infrared spectroscopy. Then, the SiON layer was deposited as a capping layer on a 10 nm thick Al2O3 layer, and the electrical and optical properties were analyzed. The SiON capping layer with n = 1.47 and a thickness of 70 nm resulted in an interface trap density of 4.74 = 1010 cm-2 eV-1 and Q f of -2.59 = 1012 cm-2 with a substantial improvement in lifetime of 1.52 ms after industrial firing. The incorporation of an Al2O3/SiON stack on the front side of the n-type solar cells results in an energy conversion efficiency of 18.34% compared to the one with Al2O3/a-SiNx:H showing 17.55% efficiency. The short circuit current density and open circuit voltage increase by up to 0.83 mA cm-2 and 12 mV, respectively, compared to the Al2O3/a-SiNx:H stack on the front side of the n-type solar cells due to the good anti-reflection and front side surface passivation.

  3. Duplex aluminized coatings

    NASA Technical Reports Server (NTRS)

    Gedwill, M. A.; Grisaffe, S. J. (Inventor)

    1975-01-01

    The surface of a metallic base system is initially coated with a metallic alloy layer that is ductile and oxidation resistant. An aluminide coating is then applied to the metallic alloy layer. The chemistry of the metallic alloy layer is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded.

  4. Coated ceramic breeder materials

    DOEpatents

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-04-07

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  5. Thermal barrier coating

    DOEpatents

    Bowker, Jeffrey Charles; Sabol, Stephen M.; Goedjen, John G.

    2001-01-01

    A thermal barrier coating for hot gas path components of a combustion turbine based on a zirconia-scandia system. A layer of zirconium scandate having the hexagonal Zr.sub.3 Sc.sub.4 O.sub.12 structure is formed directly on a superalloy substrate or on a bond coat formed on the substrate.

  6. Molecular Adsorber Coating

    NASA Technical Reports Server (NTRS)

    Straka, Sharon; Peters, Wanda; Hasegawa, Mark; Hedgeland, Randy; Petro, John; Novo-Gradac, Kevin; Wong, Alfred; Triolo, Jack; Miller, Cory

    2011-01-01

    A document discusses a zeolite-based sprayable molecular adsorber coating that has been developed to alleviate the size and weight issues of current ceramic puck-based technology, while providing a configuration that more projects can use to protect against degradation from outgassed materials within a spacecraft, particularly contamination-sensitive instruments. This coating system demonstrates five times the adsorption capacity of previously developed adsorber coating slurries. The molecular adsorber formulation was developed and refined, and a procedure for spray application was developed. Samples were spray-coated and tested for capacity, thermal optical/radiative properties, coating adhesion, and thermal cycling. Work performed during this study indicates that the molecular adsorber formulation can be applied to aluminum, stainless steel, or other metal substrates that can accept silicate-based coatings. The coating can also function as a thermal- control coating. This adsorber will dramatically reduce the mass and volume restrictions, and is less expensive than the currently used molecular adsorber puck design.

  7. Coated electroactive materials

    DOEpatents

    Amine, Khalil; Abouimrane, Ali

    2016-08-30

    A process includes suspending an electroactive material in a solvent, suspending or dissolving a carbon precursor in the solvent; and depositing the carbon precursor on the electroactive material to form a carbon-coated electroactive material. Compositions include a graphene-coated electroactive material prepared from a solution phase mixture or suspension of an electroactive material and graphene, graphene oxide, or a mixture thereof.

  8. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S. (Inventor)

    1985-01-01

    An oxide thermal barrier coating comprises ZrO3-Yb2O3 that is plasma sprayed onto a previously applied bond coating. The zirconia is partially stabilized with about 124 w/o ytterbia to insure cubic, monoclinic, and terragonal phases.

  9. Anti-Corrosion Coating

    NASA Technical Reports Server (NTRS)

    1977-01-01

    NASA-Goddard developed a zinc-rich coating with a special binder that exhibits longer life and booths with the air purifiers. superior adhesion characteristics-so that only a single coat is required. Unlike conventional coatings, . the NASA compound is easy to mix and it requires no straining before application; its materials also cost less. Thus the new coating offers cost advantages in materials, labor hours per application, and fewer applications over a given time span. The NASA coating is now undergoing test on a number of coastal area structures. In a cooperative effort with the Philadelphia Mayor's Science and Technology Council, the coating has been applied to sample sections of the Frankford Elevated System's steel support structure. On the West Coast, it is being tested on facilities of the Pillar Point Satellite Tracking Station, Pillar Point, Cat. and on segments of the Golden Gate Bridge. It is also undergoing evaluation as an undercoating to protect road equipment against de-icing salts; the coating was applied to the underside of a truck and its performance is being recorded periodically by the Vermont Department of Highways. NASA has issued patent licenses to two paint companies and the coating is expected to be commercially available this year.

  10. Coated ceramic breeder materials

    DOEpatents

    Tam, Shiu-Wing; Johnson, Carl E.

    1987-01-01

    A breeder material for use in a breeder blanket of a nuclear reactor is disclosed. The breeder material comprises a core material of lithium containing ceramic particles which has been coated with a neutron multiplier such as Be or BeO, which coating has a higher thermal conductivity than the core material.

  11. Thermal barrier coatings

    SciTech Connect

    Alvin, Mary Anne

    2010-06-22

    This disclosure addresses the issue of providing a metallic-ceramic overlay coating that potentially serves as an interface or bond coat layer to provide enhanced oxidation resistance to the underlying superalloy substrate via the formation of a diffusion barrier regime within the supporting base material. Furthermore, the metallic-ceramic coating is expected to limit the growth of a continuous thermally grown oxide (TGO) layer that has been primarily considered to be the principal cause for failure of existing TBC systems. Compositional compatibility of the metallic-ceramic with traditional yttria-stabilized zirconia (YSZ) top coats is provided to further limit debond or spallation of the coating during operational use. A metallic-ceramic architecture is disclosed wherein enhanced oxidation resistance is imparted to the surface of nickel-based superalloy or single crystal metal substrate, with simultaneous integration of the yttria stabilized zirconia (YSZ) within the metallic-ceramic overlayer.

  12. LEVELING METAL COATINGS

    DOEpatents

    Gage, H.A.

    1959-02-10

    A method is described for applying metallic coatings to a cylinder of uranium. An aluminum-silicon coat is applied by a process consisting of first cleaning the article by immersion for 5 minutes in 50% nitric acid at 65 C. The article then is dipped through a flux, prepared by adding 10% sodium fluoride to 90% of a flux comprising 53% potassium chloride, 42% lithium chloride, and 5% sodium chloride at 560 for 2 minutes and then directly into a molten metal bath comprising 99% aluminun and 12% silicon at 620 C for 3 minutes. While the coating is yet molten the article is transferred to a pair of steel rollers and rolled until the coating solidifies. By varying the composition of the flux other metals such as zinc, lead or the like may be coated on uranium in a similar manner.

  13. Catalytic thermal barrier coatings

    DOEpatents

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  14. Coating Reduces Ice Adhesion

    NASA Technical Reports Server (NTRS)

    Smith, Trent; Prince, Michael; DwWeese, Charles; Curtis, Leslie

    2008-01-01

    The Shuttle Ice Liberation Coating (SILC) has been developed to reduce the adhesion of ice to surfaces on the space shuttle. SILC, when coated on a surface (foam, metal, epoxy primer, polymer surfaces), will reduce the adhesion of ice by as much as 90 percent as compared to the corresponding uncoated surface. This innovation is a durable coating that can withstand several cycles of ice growth and removal without loss of anti-adhesion properties. SILC is made of a binder composed of varying weight percents of siloxane(s), ethyl alcohol, ethyl sulfate, isopropyl alcohol, and of fine-particle polytetrafluoroethylene (PTFE). The combination of these components produces a coating with significantly improved weathering characteristics over the siloxane system alone. In some cases, the coating will delay ice formation and can reduce the amount of ice formed. SILC is not an ice prevention coating, but the very high water contact angle (greater than 140 ) causes water to readily run off the surface. This coating was designed for use at temperatures near -170 F (-112 C). Ice adhesion tests performed at temperatures from -170 to 20 F (-112 to -7 C) show that SILC is a very effective ice release coating. SILC can be left as applied (opaque) or buffed off until the surface appears clear. Energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) data show that the coating is still present after buffing to transparency. This means SILC can be used to prevent ice adhesion even when coating windows or other objects, or items that require transmission of optical light. Car windshields are kept cleaner and SILC effectively mitigates rain and snow under driving conditions.

  15. Cubic zirconia as a high-quality facet coating for semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Chin, A. K.; Satyanarayan, A.; Zarrabi, J. H.; Vetterling, W.

    1988-08-01

    In this paper we describe the properties of high-quality, semiconductor laser facet coatings based on yttria-stabilizied cubic zirconia (90-m% ZrO2/10-m% Y2O3). We have found that cubic zirconia films can be reproducibly deposited by electron-beam evaporation with an index of refraction of 1.98 at 6328 Å, almost ideal for use as a single-layer antireflection coating for GaAs/GaAlAs-based lasers. ZrO2 has a monoclinic crystal structure at room temperature, but changes to tetragonal, hexagonal, and cubic phases upon heating to higher temperatures. However, the addition of the Y2O3 stabilizes ZrO2 in the cubic form, thus allowing electron-beam deposition of thin films of this material to be more controllable and reproducible without the usual addition of oxygen into the vacuum chamber during deposition. Preliminary aging tests of high-power GaAs/GaAlAs lasers show that cubic zirconia films suppress the photo-enhanced oxidation of laser facets that degrades device performance.

  16. Effect of a Silicone Contaminant Film on the Transmittance Properties of AR-coated Fused Silica

    NASA Technical Reports Server (NTRS)

    Boeder, Paul A.; Visentine, James T.; Shaw, Christopher G.; Carniglia, Charles K.; Ledbury, Eugene A.; Alred, John W.; Soares, Carlos E.

    2004-01-01

    We present the results of a laboratory test to determine the effects of bulk deposited, DC-704 silicone contaminant film on the transmittance properties of an anti-reflective (AR) coated fused silica optical substrate. Testing and optical measurements were performed in vacuum in the Boeing Combined Effects Test Facility (CETF). The test and measurement procedures are described herein. Measurement results are presented showing the change in transmittance characteristics as a function of contaminant deposit thickness and vacuum ultra-violet (vuv) exposure levels. Measurement results show an initial degradation in the transmittance of the contaminated sample. This is followed by a partial recovery in sample transmittance as the sample is exposed to additional VUV radiation. Transmittance results also show a loss of transmission in the ultraviolet portion of the spectrum and an increase in transmission in the infrared portion of the spectrum. These transmittance results are characteristic of thin-film interference effects. Thin-film analyses indicate that some of the observed transmittance results can be successfully modeled, but only if the contaminant film is assumed to be SiO2 rather than DC-704 silicone. Post-test Scanning Electron Microscope (SEM) scans of the test sample indicate the formation of contaminant islands and the presence of a thin uniform coating of contaminant deposit on the sample

  17. POSS(Registered TradeMark) Coatings for Solar Cells: An Update

    NASA Technical Reports Server (NTRS)

    Brandhorst, Henry; Isaacs-Smith, Tamara; Wells, Brian; Lichtenhan, Joseph D.; Fu, Bruce X.

    2007-01-01

    Presently, solar cells are covered with Ce-doped microsheet cover glasses that are attached with Dow Corning DC 93-500 silicone adhesive. Various antireflection coatings are often applied to the cover glass to increase cell performance. This general approach has been used from the beginning of space exploration. However, it is expensive and time consuming. Furthermore, as the voltage of solar arrays increases, significant arcing has occurred in solar arrays, leading to loss of satellite power. The cause has been traced to differential voltages between strings and the close spacing between them with no insulation covering the edges of the solar cells. In addition, this problem could be ameliorated if the cover glass extended over the edges of the cell, but this would impact packing density. An alternative idea that might solve all these issues and be less expensive and more protective is to develop a coating that could be applied over the entire array. Such a coating must be resistant to atomic oxygen for low earth orbits below about 700 km, it must be resistant to ultraviolet radiation for all earth and near-sun orbits and, of course, it must withstand the damaging effects of space radiation. Coating flexibility would be an additional advantage. Based on past experience, one material that has many of the desired attributes of a universal protective coating is the Dow Corning DC 93-500. Of all the potential optical plastics, it appears to be the most suitable for use in space. As noted above, DC 93-500 has been extensively used to attach cover glasses to crystalline solar cells and has worked exceptionally well over the years. It is flexible and generally resistant to electrons, protons and ultraviolet (UV and VUV) radiation; although a VUV-rejection coating or VUV-absorbing ceria-doped cover glass may be required for long mission durations. It can also be applied in a thin coating (< 25 m) by conventional liquid coating processes. Unfortunately, when exposed to

  18. Study by simulation of the SnO2 and ZnO anti-reflection layers in n-SiC/p-SiC solar cells

    NASA Astrophysics Data System (ADS)

    Zerfaoui, Hana; Dib, Djalel; Rahmani, Mohamed; Benyelloul, Kamel; Mebarkia, Chafia

    2016-07-01

    Recently, Two technologies of the photovoltaic cells are present today namely the cells crystalline (polycrystalline and monocrystalline) and the cell thin layers. The development of the solar cells requires a technological change of materials used in their manufacturing. The thin layers are parts of these materials and which announced their effectiveness and growth of output of the solar cell. The aim of this paper article is to the study and simulation of photovoltaic cells containing SiC materials. This material is have important having a part in the development of renewable energies. Based on the SCAPS (a Solar Cell Capacitance Simulator) simulation, the obtained results are Vco, Jsc, FF and the output energy of conversion of a solar cell n-SiC/p-SiC with different materials for the anti-reflecting layer ZnO and SnO2.with the SCAPS (a Solar Cell Capacitance Simulator) computer code in one dimension, the results obtained after optimization.

  19. Silicon-based anti-reflective spin-on hardmask materials for 45 nm pattern of immersion ArF lithography

    NASA Astrophysics Data System (ADS)

    Kim, Sang Kyun; Cho, Hyeon Mo; Koh, Sang Ran; Kim, Mi-young; Yoon, Hui Chan; Chung, Yong-jin; Kim, Jong Seob; Chang, Tuwon

    2008-03-01

    In current semiconductor manufacturing processes, hardmasks have become more prevalent in patterning of small features. A silicon-containing hardmask, which can be spun onto wafers, is desirable in terms of mass production throughput and cost of ownership. Previously, we reported a paper on silicon-based anti-reflective spin-on hardmask materials for 193 nm lithography. In this paper, hardmask materials for 45 nm pattern of immersion ArF lithography are described. To achieve 45 nm patterning, a different base resin platform from the previous paper has been used. Furthermore, we have improved the etch resistance by changing our synthesis method without modifying the resin platform and silicon contents. Despite these changes, an excellent storage stability, which is one of the essential requirements for the materials, is still maintained. Characterization and lithographic performance of 45 nm immersion ArF lithography using our new materials are described in detail.

  20. Optimized broad band and quasi-omnidirectional anti-reflection properties with moth-eye structures by low cost replica molding

    NASA Astrophysics Data System (ADS)

    Shen, Ling; Du, Huiwei; Yang, Jie; Ma, Zhongquan

    2015-01-01

    Averaged over wavelength range from 500 to 1600 nm at normal incidence, the reflection losses of silicon wafer as master mold are reduced from original 35% to only 0.2% after integrating surface moth-eye structures, and glass slide suppresses the reflection from 7.5% to near 0.4% after incorporating polymer-based moth eyes on double side by replica molding that enables transferring moth eyes from master mold of silicon onto any substrate. An outstanding anti-reflective property out to large incident angles is realized with the average reflection below 0.5% until 50°, below 2.5% at 60° and below 7.5% at 70°, which holds promise for solar cell application.