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Sample records for deposited thin films

  1. Biomimetic thin film deposition

    NASA Astrophysics Data System (ADS)

    Rieke, P. C.; Campbell, A. A.; Tarasevich, B. J.; Fryxell, G. E.; Bentjen, S. B.

    1991-04-01

    Surfaces derivatized with organic functional groups were used to promote the deposition of thin films of inorganic minerals. These derivatized surfaces were designed to mimic the nucleation proteins that control mineral deposition during formation of bone, shell, and other hard tissues in living organisms. By the use of derivatized substrates control was obtained over the phase of mineral deposited, the orientation of the crystal lattice and the location of deposition. These features are of considerable importance in many technically important thin films, coatings, and composite materials. Methods of derivatizing surfaces are considered and examples of controlled mineral deposition are presented.

  2. VACUUM DEPOSITION OF THIN FILMS,

    DTIC Science & Technology

    The book deals with methods of obtaining and processing thin films , methods of measuring the deposition rate and thickness of thin-film layers, and...the main fields of application of thin films . Vacuum requirements and the requirements for the composition of the residual medium in thermal...evaporation and cathode sputtering are given, and modern methods of producing and measuring vacuums and the equipment used in obtaining thin films are described. (Author)

  3. Vapor deposition of thin films

    DOEpatents

    Smith, David C.; Pattillo, Stevan G.; Laia, Jr., Joseph R.; Sattelberger, Alfred P.

    1992-01-01

    A highly pure thin metal film having a nanocrystalline structure and a process of preparing such highly pure thin metal films of, e.g., rhodium, iridium, molybdenum, tungsten, rhenium, platinum, or palladium by plasma assisted chemical vapor deposition of, e.g., rhodium(allyl).sub.3, iridium(allyl).sub.3, molybdenum(allyl).sub.4, tungsten(allyl).sub.4, rhenium(allyl).sub.4, platinum(allyl).sub.2, or palladium(allyl).sub.2 are disclosed. Additionally, a general process of reducing the carbon content of a metallic film prepared from one or more organometallic precursor compounds by plasma assisted chemical vapor deposition is disclosed.

  4. Characteristics Of Vacuum Deposited Sucrose Thin Films

    NASA Astrophysics Data System (ADS)

    Ungureanu, F.; Predoi, D.; Ghita, R. V.; Vatasescu-Balcan, R. A.; Costache, M.

    Thin films of sucrose (C12H22O11) were deposited on thin cut glass substrates by thermal evaporation technique (p ~ 10-5 torr). The surface morphology was putted into evidence by FT-IR and SEM analysis. The experimental results confirm a uniform deposition of an adherent sucrose layer. The biological tests (e.g., cell morphology and cell viability evaluated by measuring mitochondrial dehydrogenise activity with MTT assay) confirm the properties of sucrose thin films as bioactive material. The human fetal osteoblast system grown on thin sucrose film was used for the determination of cell proliferation, cell viability and cell morphology studies.

  5. Liquid phase deposition of electrochromic thin films

    SciTech Connect

    Richardson, Thomas J.; Rubin, Michael D.

    2000-08-18

    Thin films of titanium, zirconium and nickel oxides were deposited on conductive SnO2:F glass substrates by immersion in aqueous solutions. The films are transparent, conformal, of uniform thickness and appearance, and adhere strongly to the substrates. On electrochemical cycling, TiO2, mixed TiO2-ZrO2, and NiOx films exhibited stable electrochromism with high coloration efficiencies. These nickel oxide films were particularly stable compared with films prepared by other non-vacuum techniques. The method is simple, inexpensive, energy efficient, and readily scalable to larger substrates.

  6. Thin Film Deposition Using Energetic Ions

    PubMed Central

    Manova, Darina; Gerlach, Jürgen W.; Mändl, Stephan

    2010-01-01

    One important recent trend in deposition technology is the continuous expansion of available processes towards higher ion assistance with the subsequent beneficial effects to film properties. Nowadays, a multitude of processes, including laser ablation and deposition, vacuum arc deposition, ion assisted deposition, high power impulse magnetron sputtering and plasma immersion ion implantation, are available. However, there are obstacles to overcome in all technologies, including line-of-sight processes, particle contaminations and low growth rates, which lead to ongoing process refinements and development of new methods. Concerning the deposited thin films, control of energetic ion bombardment leads to improved adhesion, reduced substrate temperatures, control of intrinsic stress within the films as well as adjustment of surface texture, phase formation and nanotopography. This review illustrates recent trends for both areas; plasma process and solid state surface processes. PMID:28883323

  7. Iridium thin films deposited via pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Chen, Chenglin

    High purity Ir thin films for future applications as transition-edge sensors were deposited on Si (100) via pulsed laser deposition. The iridium deposition rate was investigated and found to have a high value with the pulsed laser power higher than 4.2×10 9 W/cm 2 . At this laser intensity range, the PLD Ir films were deposited at substrate temperature ranging from 100 to 700°C. Ir thin films' characteristics were investigated at both room temperature and low temperature with the emphasis on study of the effect of the substrate temperature during deposition on the structure and morphology of the films. The PLD films exhibited a (110) preferentially oriented polycrystalline structure. Their average grain size increased from about 30 to 110 nm as the deposition temperature was raised from 100 to 600°C. With a 700°C substrate temperature the grain size jumped to 500 nm. Iridium silicide was found in the film deposited at 700°C substrate temperature. This indicated a critical deposition temperature between 600 and 700°C. A 50 mK platform was built for low temperature measurements. At low temperature, the Residual Resistance Ratio (RRR) of the Ir thin films had a typical value of 1.50. A typical transition curve of the film showed a transition temperature higher and wider than expected.

  8. Pulsed laser deposition of ferroelectric thin films

    NASA Astrophysics Data System (ADS)

    Sengupta, Somnath; McKnight, Steven H.; Sengupta, Louise C.

    1997-05-01

    It has been shown that in bulk ceramic form, the barium to strontium ratio in barium strontium titanium oxide (Ba1- xSrxTiO3, BSTO) affects the voltage tunability and electronic dissipation factor in an inverse fashion; increasing the strontium content reduces the dissipation factor at the expense of lower voltage tunability. However, the oxide composites of BSTO developed at the Army Research Laboratory still maintain low electronic loss factors for all compositions examined. The intent of this study is to determine whether such effects can be observed in the thin film form of the oxide composites. The pulsed laser deposition (PLD) method has been used to deposit the thin films. The different compositions of the compound (with 1 wt% of the oxide additive) chosen were: Ba0.3Sr0.7TiO3, Ba0.4Sr0.6TiO3, Ba0.5Sr0.5TiO3, Ba0.6Sr0.4TiO3, and Ba0.7Sr0.3TiO3. The electronic properties investigated in this study were the dielectric constant and the voltage tunability. The morphology of the thin films were examined using the atomic force microscopy. Fourier transform Raman spectroscopy was also utilized for optical characterization of the thin films. The electronic and optical properties of the thin films and the bulk ceramics were compared. The results of these investigations are discussed.

  9. Physical Vapor Deposition of Thin Films

    NASA Astrophysics Data System (ADS)

    Mahan, John E.

    2000-01-01

    A unified treatment of the theories, data, and technologies underlying physical vapor deposition methods With electronic, optical, and magnetic coating technologies increasingly dominating manufacturing in the high-tech industries, there is a growing need for expertise in physical vapor deposition of thin films. This important new work provides researchers and engineers in this field with the information they need to tackle thin film processes in the real world. Presenting a cohesive, thoroughly developed treatment of both fundamental and applied topics, Physical Vapor Deposition of Thin Films incorporates many critical results from across the literature as it imparts a working knowledge of a variety of present-day techniques. Numerous worked examples, extensive references, and more than 100 illustrations and photographs accompany coverage of: * Thermal evaporation, sputtering, and pulsed laser deposition techniques * Key theories and phenomena, including the kinetic theory of gases, adsorption and condensation, high-vacuum pumping dynamics, and sputtering discharges * Trends in sputter yield data and a new simplified collisional model of sputter yield for pure element targets * Quantitative models for film deposition rate, thickness profiles, and thermalization of the sputtered beam

  10. Pulsed laser deposition of pepsin thin films

    NASA Astrophysics Data System (ADS)

    Kecskeméti, G.; Kresz, N.; Smausz, T.; Hopp, B.; Nógrádi, A.

    2005-07-01

    Pulsed laser deposition (PLD) of organic and biological thin films has been extensively studied due to its importance in medical applications among others. Our investigations and results on PLD of a digestion catalyzing enzyme, pepsin, are presented. Targets pressed from pepsin powder were ablated with pulses of an ArF excimer laser ( λ = 193 nm, FWHM = 30 ns), the applied fluence was varied between 0.24 and 5.1 J/cm 2. The pressure in the PLD chamber was 2.7 × 10 -3 Pa. The thin layers were deposited onto glass and KBr substrates. Our IR spectroscopic measurements proved that the chemical composition of deposited thin films is similar to that of the target material deposited at 0.5 and 1.3 J/cm 2. The protein digesting capacity of the transferred pepsin was tested by adapting a modified "protein cube" method. Dissolution of the ovalbumin sections proved that the deposited layers consisted of catalytically active pepsin.

  11. Substrate heater for thin film deposition

    DOEpatents

    Foltyn, Steve R.

    1996-01-01

    A substrate heater for thin film deposition of metallic oxides upon a target substrate configured as a disk including means for supporting in a predetermined location a target substrate configured as a disk, means for rotating the target substrate within the support means, means for heating the target substrate within the support means, the heating means about the support means and including a pair of heating elements with one heater element situated on each side of the predetermined location for the target substrate, with one heater element defining an opening through which desired coating material can enter for thin film deposition and with the heating means including an opening slot through which the target substrate can be entered into the support means, and, optionally a means for thermal shielding of the heating means from surrounding environment is disclosed.

  12. Deposition and characterization of CuInS2 thin films deposited over copper thin films

    NASA Astrophysics Data System (ADS)

    Thomas, Titu; Kumar, K. Rajeev; Kartha, C. Sudha; Vijayakumar, K. P.

    2015-06-01

    Simple, cost effective and versatile spray pyrolysis method is effectively combined with vacuum evaporation for the deposition of CuIns2 thin films for photovoltaic applications. In the present study In2s3 was spray deposited over vacuum evaporated Cu thin films and Cu was allowed to diffuse in to the In2S3 layer to form CuInS2. To analyse the dependence of precursor volume on the formation of CuInS2 films structural, electrical and morphological analzes are carried out. Successful deposition of CuInS2thin films with good crystallinity and morphology with considerably low resistivity is reported in this paper.

  13. Vapor deposition routes to conformal polymer thin films

    PubMed Central

    Moni, Priya; Al-Obeidi, Ahmed

    2017-01-01

    Vapor phase syntheses, including parylene chemical vapor deposition (CVD) and initiated CVD, enable the deposition of conformal polymer thin films to benefit a diverse array of applications. This short review for nanotechnologists, including those new to vapor deposition methods, covers the basic theory in designing a conformal polymer film vapor deposition, sample preparation and imaging techniques to assess film conformality, and several applications that have benefited from vapor deposited, conformal polymer thin films. PMID:28487816

  14. Apparatus for laser assisted thin film deposition

    DOEpatents

    Warner, Bruce E.; McLean, II, William

    1996-01-01

    A pulsed laser deposition apparatus uses fiber optics to deliver visible output beams. One or more optical fibers are coupled to one or more laser sources, and delivers visible output beams to a single chamber, to multiple targets in the chamber or to multiple chambers. The laser can run uninterrupted if one of the deposition chambers ceases to operate because other chambers can continue their laser deposition processes. The laser source can be positioned at a remote location relative to the deposition chamber. The use of fiber optics permits multi-plexing. A pulsed visible laser beam is directed at a generally non-perpendicular angle upon the target in the chamber, generating a plume of ions and energetic neutral species. A portion of the plume is deposited on a substrate as a thin film. A pulsed visible output beam with a high pulse repetition frequency is used. The high pulse repetition frequency is greater than 500 Hz, and more preferably, greater than about 1000 Hz. Diamond-like-carbon (DLC) is one of the thin films produced using the apparatus.

  15. Apparatus for laser assisted thin film deposition

    DOEpatents

    Warner, B.E.; McLean, W. II

    1996-02-13

    A pulsed laser deposition apparatus uses fiber optics to deliver visible output beams. One or more optical fibers are coupled to one or more laser sources, and delivers visible output beams to a single chamber, to multiple targets in the chamber or to multiple chambers. The laser can run uninterrupted if one of the deposition chambers ceases to operate because other chambers can continue their laser deposition processes. The laser source can be positioned at a remote location relative to the deposition chamber. The use of fiber optics permits multi-plexing. A pulsed visible laser beam is directed at a generally non-perpendicular angle upon the target in the chamber, generating a plume of ions and energetic neutral species. A portion of the plume is deposited on a substrate as a thin film. A pulsed visible output beam with a high pulse repetition frequency is used. The high pulse repetition frequency is greater than 500 Hz, and more preferably, greater than about 1000 Hz. Diamond-like-carbon (DLC) is one of the thin films produced using the apparatus. 9 figs.

  16. A study of reactive plasma deposited thin films

    NASA Technical Reports Server (NTRS)

    Gilchrist, J.; Williams, E.

    1986-01-01

    A state-of-the-art research laboratory was established to grow and characterize amorphous thin films that are useful in semi-conductor devices. Two film systems, nitride films and silicon dioxide films were studied. Over seventy deposition runs for nitride films were made. The films were deposited on silicon substrate using plasma enhanced chemical vapor deposition. It was found that the uniformity of the films were affected by the location of the film on the platen.

  17. Studies of Niobium Thin Film Produced by Energetic Vacuum Deposition

    SciTech Connect

    Genfa Wu; Anne-Marie Valente; H. Phillips; Haipeng Wang; Andy Wu; T. J. Renk; P Provencio

    2004-05-01

    An energetic vacuum deposition system has been used to study deposition energy effects on the properties of niobium thin films on copper and sapphire substrates. The absence of working gas avoids the gaseous inclusions commonly seen with sputtering deposition. A biased substrate holder controls the deposition energy. Transition temperature and residual resistivity ratio of the niobium thin films at several deposition energies are obtained together with surface morphology and crystal orientation measurements by AFM inspection, XRD and TEM analysis. The results show that niobium thin films on sapphire substrate exhibit the best cryogenic properties at deposition energy around 123 eV. The TEM analysis revealed that epitaxial growth of film was evident when deposition energy reaches 163 eV for sapphire substrate. Similarly, niobium thin film on copper substrate shows that film grows more oriented with higher deposition energy and grain size reaches the scale of the film thickness at the deposition energy around 153 eV.

  18. Bismuth thin films obtained by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Flores, Teresa; Arronte, Miguel; Rodriguez, Eugenio; Ponce, Luis; Alonso, J. C.; Garcia, C.; Fernandez, M.; Haro, E.

    1999-07-01

    In the present work Bi thin films were obtained by Pulsed Laser Deposition, using Nd:YAG lasers. The films were characterized by optical microscopy. Raman spectroscopy and X-rays diffraction. It was accomplished the real time spectral emission characterization of the plasma generated during the laser evaporation process. Highly oriented thin films were obtained.

  19. Recent progress of obliquely deposited thin films for industrial applications

    NASA Astrophysics Data System (ADS)

    Suzuki, Motofumi; Itoh, Tadayoshi; Taga, Yasunori

    1999-06-01

    More than 10 years ago, birefringent films of metal oxides were formed by oblique vapor deposition and investigated with a view of their application to optical retardation plates. The retardation function of the films was explained in terms of the birefringence caused by the characteristic anisotropic nanostructure inside the films. These films are now classified in the genre of the so-called sculptured thin films. However, the birefringent films thus prepared are not yet industrialized even now due to the crucial lack of the durability and the yield of products. In this review paper, we describe the present status of application process of the retardation films to the information systems such as compact disc and digital versatile disc devices with a special emphasis on the uniformity of retardation properties in a large area and the stability of the optical properties of the obliquely deposited thin films. Finally, further challenges for wide application of the obliquely deposited thin films are also discussed.

  20. Deposition of thin films of multicomponent materials

    NASA Technical Reports Server (NTRS)

    Thakoor, Sarita (Inventor)

    1993-01-01

    Composite films of multicomponent materials, such as oxides and nitrides, e.g., lead zirconate titanate, are deposited by dc magnetron sputtering, employing a rotating substrate holder, which rotates relative to a plurality of targets, one target for each metal element of the multicomponent material. The sputtering is carried out in a reactive atmosphere. The substrates on which the layers are deposited are at ambient temperature. Following deposition of the composite film, the film is heated to a temperature sufficient to initiate a solid state reaction and form the final product, which is substantially single phase and substantially homogeneous.

  1. Thin film deposition using rarefied gas jet

    NASA Astrophysics Data System (ADS)

    Pradhan, Sahadev, , Dr.

    2017-01-01

    The rarefied gas jet of aluminium is studied at Mach number Ma =(U_j /√{ kbTj / m }) in the range .01 deposition mechanisms in a physical vapor deposition (PVD) process for the development of the highly oriented pure metallic aluminum thin film with uniform thickness and strong adhesion on the surface of the substrate in the form of ionic plasma, so that the substrate can be protected from corrosion and oxidation and thereby enhance the lifetime and safety, and to introduce the desired surface properties for a given application. Here, H is the characteristic dimension, U_j and T_j are the jet velocity and temperature, n_d is the number density of the jet, m and d are the molecular mass and diameter, and kb is the Boltzmann constant. An important finding is that the capture width (cross-section of the gas jet deposited on the substrate) is symmetric around the centerline of the substrate, and decreases with increased Mach number due to an increase in the momentum of the gas molecules. DSMC simulation results reveals that at low Knudsen number ((Kn =0.01); shorter mean free paths), the atoms experience more collisions, which direct them toward the substrate. However, the atoms also move with lower momentum at low Mach number ,which allows scattering collisions to rapidly direct the atoms to the substrate.

  2. Thin film deposition using rarefied gas jet

    NASA Astrophysics Data System (ADS)

    Pradhan, Sahadev, , Dr.

    2016-11-01

    The rarefied gas jet of aluminium is studied at Mach number Ma = (Uj /√{ kbTj / m }) in the range .01 deposition mechanisms in a physical vapor deposition (PVD) process for the development of the highly oriented pure metallic aluminum thin film with uniform thickness and strong adhesion on the surface of the substrate in the form of ionic plasma, so that the substrate can be protected from corrosion and oxidation and thereby enhance the lifetime and safety, and to introduce the desired surface properties for a given application. Here, His the characteristic dimension, Uj and Tj are the jet velocity and temperature, nd is the number density of the jet, m and d are the molecular mass and diameter, and kb is the Boltzmann constant. An important finding is that the capture width (cross-section of the gas jet deposited on the substrate) is symmetric around the centerline of the substrate, and decreases with increased Mach number due to an increase in the momentum of the gas molecules. DSMC simulation results reveals that at low Knudsen number ((Kn = 0 . 01) ; shorter mean free paths), the atoms experience more collisions, which direct them toward the substrate. However, the atoms also move with lower momentum at low Mach number, which allows scattering collisions to rapidly direct the atoms to the substrate.

  3. Thin film deposition using rarefied gas jet

    NASA Astrophysics Data System (ADS)

    Pradhan, Sahadev

    2016-10-01

    The rarefied gas jet of aluminium is studied at Mach number Ma =(U_j ∖√{ kbTj / m }) in the range .01 deposition mechanisms in a physical vapor deposition (PVD) process for the development of the highly oriented pure metallic aluminum thin film with uniform thickness and strong adhesion on the surface of the substrate in the form of ionic plasma, so that the substrate can be protected from corrosion and oxidation and thereby enhance the lifetime and safety, and to introduce the desired surface properties for a given application. Here, H is the characteristic dimension, U_j and T_j are the jet velocity and temperature, n_d is the number density of the jet, m and d are the molecular mass and diameter, and kb is the Boltzmann constant. An important finding is that the capture width (cross-section of the gas jet deposited on the substrate) is symmetric around the centerline of the substrate, and decreases with increased Mach number due to an increase in the momentum of the gas molecules. DSMC simulation results reveals that at low Knudsen number ((Kn = 0.01); shorter mean free paths), the atoms experience more collisions, which direct them toward the substrate. However, the atoms also move with lower momentum at low Mach number ,which allows scattering collisions to rapidly direct the atoms to the substrate.

  4. Ion plating technique improves thin film deposition

    NASA Technical Reports Server (NTRS)

    Mattox, D. M.

    1968-01-01

    Ion plating technique keeps the substrate surface clean until the film is deposited, allows extensive diffusion and chemical reaction, and joins insoluble or incompatible materials. The technique involves the deposition of ions on the substrate surface while it is being bombarded with inert gas ions.

  5. Pulsed Laser Deposition of Nanoporous Cobalt Thin Films

    PubMed Central

    Jin, Chunming; Nori, Sudhakar; Wei, Wei; Aggarwal, Ravi; Kumar, Dhananjay; Narayan, Roger J.

    2013-01-01

    Nanoporous cobalt thin films were deposited on anodized aluminum oxide (AAO) membranes at room temperature using pulsed laser deposition. Scanning electron microscopy demonstrated that the nanoporous cobalt thin films retained the monodisperse pore size and high porosity of the anodized aluminum oxide substrates. Temperature- and field-dependent magnetic data obtained between 10 K and 350 K showed large hysteresis behavior in these materials. The increase of coercivity values was larger for nanoporous cobalt thin films than for multilayered cobalt/alumina thin films. The average diameter of the cobalt nanograins in the nanoporous cobalt thin films was estimated to be ~5 nm for blocking temperatures near room temperature. These results suggest that pulsed laser deposition may be used to fabricate nanoporous magnetic materials with unusual properties for biosensing, drug delivery, data storage, and other technological applications. PMID:19198344

  6. Pulsed laser deposition of nanoporous cobalt thin films.

    PubMed

    Jin, Chunming; Nori, Sudhakar; Wei, Wei; Aggarwal, Ravi; Kumar, Dhananjay; Narayan, Roger J

    2008-11-01

    Nanoporous cobalt thin films were deposited on anodized aluminum oxide (AAO) membranes at room temperature using pulsed laser deposition. Scanning electron microscopy demonstrated that the nanoporous cobalt thin films retained the monodisperse pore size and high porosity of the anodized aluminum oxide substrates. Temperature- and field-dependent magnetic data obtained between 10 K and 350 K showed large hysteresis behavior in these materials. The increase of coercivity values was larger for nanoporous cobalt thin films than for multilayered cobalt/alumina thin films. The average diameter of the cobalt nanograins in the nanoporous cobalt thin films was estimated to be approsimately 5 nm for blocking temperatures near room temperature. These results suggest that pulsed laser deposition may be used to fabricate nanoporous magnetic materials with unusual properties for biosensing, drug delivery, data storage, and other technological applications.

  7. Nitrogen incorporation in sputter deposited molybdenum nitride thin films

    SciTech Connect

    Stöber, Laura Patocka, Florian Schneider, Michael Schmid, Ulrich; Konrath, Jens Peter Haberl, Verena

    2016-03-15

    In this paper, the authors report on the high temperature performance of sputter deposited molybdenum (Mo) and molybdenum nitride (Mo{sub 2}N) thin films. Various argon and nitrogen gas compositions are applied for thin film synthetization, and the amount of nitrogen incorporation is determined by Auger measurements. Furthermore, effusion measurements identifying the binding conditions of the nitrogen in the thin film are performed up to 1000 °C. These results are in excellent agreement with film stress and scanning electron microscope analyses, both indicating stable film properties up to annealing temperatures of 500 °C.

  8. Ultrashort pulse laser deposition of thin films

    DOEpatents

    Perry, Michael D.; Banks, Paul S.; Stuart, Brent C.

    2002-01-01

    Short pulse PLD is a viable technique of producing high quality films with properties very close to that of crystalline diamond. The plasma generated using femtosecond lasers is composed of single atom ions with no clusters producing films with high Sp.sup.3 /Sp.sup.2 ratios. Using a high average power femtosecond laser system, the present invention dramatically increases deposition rates to up to 25 .mu.m/hr (which exceeds many CVD processes) while growing particulate-free films. In the present invention, deposition rates is a function of laser wavelength, laser fluence, laser spot size, and target/substrate separation. The relevant laser parameters are shown to ensure particulate-free growth, and characterizations of the films grown are made using several diagnostic techniques including electron energy loss spectroscopy (EELS) and Raman spectroscopy.

  9. Sputter deposition of metallic thin film and directpatterning

    SciTech Connect

    Ji, L.; Chen, Y.; Jiang, X.; Ji, Q.; Leung, K.-N.

    2005-09-09

    A compact apparatus is developed for deposition of metal thin film. The system employs an RF discharge plasma source with a straight RF antenna, which is made of or covered with deposition material, serving as sputtering target at the same time. The average deposition rate of copper thin film is as high as 450nm/min. By properly allocating the metal materials on the sputtering antenna, mixture deposition of multiple metal species is achieved. Using an ion beam imprinting scheme also taking advantage of ion beam focusing technique, two different schemes of direct patterning deposition process are developed: direct depositing patterned metallic thin film and resistless ion beam sputter patterning. Preliminary experiments have demonstrated direct pattern transfer from a template with feature size of micro scale; patterns with more than 10x reduction are achieved by sputtering patterning method.

  10. Chiral thin solid films - Method of deposition and applications

    NASA Astrophysics Data System (ADS)

    Azzam, R. M. A.

    1992-12-01

    Chiral thin solid films (CTSFs) can be deposited on a solid substrate in vacuum by letting a vapor stream of film material impinge on the substrate at oblique incidence and rotating the substrate during deposition. The direction of substrate rotation determines the handedness of the resulting helical structure which resembles that of a cholesteric or twisted-nematic liquid crystal layer. CTSFs are useful in making new optical rotators and beam splitters that separate the orthogonal circular polarization components of light. A quadrant-detector ellipsometer that uses chiral and achiral obliquely deposited thin films is described for measuring the state of polarization of light.

  11. Depositing highly adhesive optical thin films on acrylic substrates.

    PubMed

    Takahashi, Tomoaki; Harada, Toshinori; Murotani, Hiroshi; Matumoto, Shigeharu

    2014-02-01

    Optical thin films are used to control the reflectance and transmittance of optical components. However, conventional deposition technologies applicable to organic (plastic) substrates typically result in weak adhesion. We overcame this problem by using vacuum deposition in combination with sputtering to directly deposit a SiO2 optical thin film onto an acrylic resin substrate. We observed neither yellowing nor deformation. The hardness of the film is 2H as measured by the pencil hardness test, indicating successful modulation of optical properties without sacrificing substrate hardness.

  12. Crystalline Indium Sulphide thin film by photo accelerated deposition technique

    NASA Astrophysics Data System (ADS)

    Dhanya, A. C.; Preetha, K. C.; Deepa, K.; Remadevi, T. L.

    2015-02-01

    Indium sulfide thin films deserve special attention because of its potential application as buffer layers in CIGS based solar cells. Highly transparent indium sulfide (InS) thin films were prepared using a novel method called photo accelerated chemical deposition (PCD). Ultraviolet source of 150 W was used to irradiate the solution. Compared to all other chemical methods, PCD scores its advantage for its low cost, flexible substrate and capable of large area of deposition. Reports on deposition of high quality InS thin films at room temperature are very rare in literature. The precursor solution was initially heated to 90°C for ten minutes and then deposition was carried out at room temperature for two hours. The appearance of the film changed from lemon yellow to bright yellow as the deposition time increased. The sample was characterized for its structural and optical properties. XRD profile showed the polycrystalline behavior of the film with mixed phases having crystallite size of 17 nm. The surface morphology of the films exhibited uniformly distributed honey comb like structures. The film appeared to be smooth and the value of extinction coefficient was negligible. Optical measurements showed that the film has more than 80% transmission in the visible region. The direct band gap energy was 2.47eV. This method is highly suitable for the synthesis of crystalline and transparent indium sulfide thin films and can be used for various photo voltaic applications.

  13. Deposition of copper selenide thin films and nanoparticles

    NASA Astrophysics Data System (ADS)

    Hu, Yunxiang; Afzaal, Mohammad; Malik, Mohammad A.; O'Brien, Paul

    2006-12-01

    A new method is reported for the growth of copper selenide thin films and nanoparticles using copper acetylacetonate and trioctylphosphine selenide. Aerosol-assisted chemical vapor deposition experiments lead to successful deposition of tetragonal Cu 2Se films. In contrast, hexadecylamine capped nanoparticles are composed of cubic Cu 2-xSe. The deposited materials are optically and structurally characterized. The results of this comprehensive study are described and discussed.

  14. Large Crystal Grain Niobium Thin Films Deposited by Energetic Condensation

    SciTech Connect

    Zhao, X.; Valente-Feliciano, A-M.; Xu, C.; Geng, R.L.; Phillips, H.; Reece, Charles; Wright, J.; Seo, K.; Crooks, R.; Krishnan, Mahadevan; Gerhan, A.; Bures, B.; Wilson, K.

    2008-01-01

    This letter presents evidence for unprecedented Nb thin films that were grown on sapphire and copper (Cu) substrates using a vacuum arc process called coaxial energetic deposition CED^TM. Most other deposition techniques with low adatom energy produce amorphous or small crystal-grain films, and typically high substrate temperatures and anneal steps is required to form the large, highly connected grains. The CED^TM technique deposits from plasma consisting of a non-equilibrium, high energy (50-150eV) ion population produced from the ionized source material. At the substrate these fast ions break up columnar structures, intermix with the first few atomic layers of the substrate to improve adhesion, and form dense films at lower substrate temperatures than are typical for low adatom energy techniques, such as physical vapor deposition (PVD). Nano-scale features of the thin films were examined using electron backscatter diffraction (EBSD). The films cryogenic state electrical properties w

  15. Organic thin film deposition in atmospheric pressure glow discharge

    SciTech Connect

    Okazaki, S.; Kogoma, M.; Yokoyama, T.; Kodama, M.; Nomiyama, H.; Ichinohe, K.

    1996-01-01

    The stabilization of a homogeneous glow discharge at atmospheric pressure has been studied since 1987. On flat surfaces, various plasma surface treatments and film depositions at atmospheric pressure have been examined. A practical application of the atmospheric pressure glow plasma on inner surfaces of flexible polyvinyl chloride tubes was tested for thin film deposition of polytetrafluoroethylene. Deposited film surfaces were characterized by ESCA and FT-IR/ATR measurements. Also SEM observation was done for platelet adhesion on the plasma treated polyvinyl chloride surface. These results showed remarkable enhancement in the inhibition to platelet adhesion on the inner surface of PVC tube, and homogeneous organic film deposition was confirmed. The deposition mechanism of polytetrafluoroethylene film in atmospheric pressure glow plasma is the same as the mechanism of film formation in the low pressure glow plasma, except for radical formation source. {copyright} {ital 1996 American Institute of Physics.}

  16. SnS2 Thin Film Deposition by Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Jaber, Abdallah Yahia; Alamri, Saleh Noaiman; Aida, Mohammed Salah

    2012-06-01

    Tin disulfide (SnS2) thin films have been synthesized using a simplified spray pyrolysis technique using a perfume atomizer. The films were deposited using two different solutions prepared by the dilution of SnCl2 and thiourea in distilled water and in methanol. The obtained films have a microcrystalline structure. The film deposited using methanol as the solvent is nearly stochiometric SnS2 with a spinel phase having a (001) preferential orientation. The film prepared with an aqueous solution is Sn-rich. Scanning electronic microscopy (SEM) images reveal that the film deposited with the aqueous solution is rough and is formed with large wires. However, the film deposited with methanol is dense and smooth. Conductivity measurements indicate that the aqueous solution leads to an n-type semiconductor, while methanol leads to a p-type semiconductor.

  17. Aluminosilicate glass thin films elaborated by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Carlier, Thibault; Saitzek, Sébastien; Méar, François O.; Blach, Jean-François; Ferri, Anthony; Huvé, Marielle; Montagne, Lionel

    2017-03-01

    In the present work, we report the elaboration of aluminosilicate glass thin films by Pulsed Laser Deposition at various temperatures deposition. The amorphous nature of glass thin films was highlighted by Grazing Incidence X-Ray Diffraction and no nanocristallites were observed in the glassy matrix. Chemical analysis, obtained with X-ray Photoelectron Spectroscopy and Time of Flight Secondary Ion Mass Spectroscopy, showed a good transfer and homogeneous elementary distribution with of chemical species from the target to the film a. Structural studies performed by Infrared Spectroscopy showed that the substrate temperature plays an important role on the bonding configuration of the layers. A slight shift of Si-O modes to larger wavenumber was observed with the synthesis temperature, assigned to a more strained sub-oxide network. Finally, optical properties of thins film measured by Spectroscopic Ellipsometry are similar to those of the bulk aluminosilicate glass, which indicate a good deposition of aluminosilicate bulk glass.

  18. Formation of diamond nanoparticle thin films by electrophoretic deposition

    NASA Astrophysics Data System (ADS)

    Goto, Yosuke; Ohishi, Fujio; Tanaka, Kuniaki; Usui, Hiroaki

    2016-03-01

    Thin films of diamond nanoparticles were prepared by electrophoretic deposition (EPD) using 0.5 wt % dispersions in water, ethanol, and 2-propanol. The film growth rate increased with increasing voltage applied to the electrodes. However, an excessive increase in voltage caused the degradation of film morphology. The optimum voltage was 4 V with an electrode separation of 5 mm. The film growth rate was higher in organic solvents than in water. The deposited film had a smooth surface with an average surface roughness comparable to the size of primary particles of the source material. It is notable that the EPD films had a considerably higher physical stability than spin-coated and cast films. The stability was further improved by thermally annealing the films. IR analysis revealed that the diamond nanoparticles have carboxy and amino groups on their surfaces. It is considered that the stability of the EPD films originate from a chemical reaction between these functional groups.

  19. Process Tuning of Silica Thin-Film Deposition

    SciTech Connect

    Keck,J.; Oliver,J.B.; Gruschow,V.; Spaulding,J.; Howe,J.

    2004-12-17

    Use of high-resolution deposition-rate monitoring and programmatic control of electron-beam position results in improvements in rate consistency and uniformity of source depletion during SiO2 thin-film deposition by electron-beam evaporation.

  20. Optimization of chemical bath deposited cadmium sulfide thin films

    SciTech Connect

    Oladeji, I.O.; Chow, L.

    1997-07-01

    Cadmium sulfide (CdS) is known to be an excellent heterojunction partner of p-type cadmium telluride (CdTe) or p-type copper indium diselenide (CuInSe{sub 2}) due essentially to its high electron affinity. It is widely used as a window material in high efficiency thin-film solar cells based on CdTe or CuInSe{sub 2} owing to its transparency and photoconductivity among other properties. The authors report the optimization of CdS thin film grown by chemical bath deposition where homogeneous reactions are minimized. The optimum parameters have enabled them to maximize the thickness of the deposited film in a single dip and to grow thicker films by periodically replenishing the concentration of reactants while the substrate remains continuously dipped in the reaction bath. Characterization results reveal the deposited CdS films exhibit improved optical and electrical properties.

  1. Polyelectrolyte Coacervates Deposited as High Gas Barrier Thin Films.

    PubMed

    Haile, Merid; Sarwar, Owais; Henderson, Robert; Smith, Ryan; Grunlan, Jaime C

    2017-01-01

    Multilayer coatings consisting of oppositely charged polyelectrolytes have proven to be extraordinarily effective oxygen barriers but require many processing steps to fabricate. In an effort to prepare high oxygen barrier thin films more quickly, a polyelectrolyte complex coacervate composed of polyethylenimine and polyacrylic acid is prepared. The coacervate fluid is applied as a thin film using a rod coating process. With humidity and thermal post-treatment, a 2 µm thin film reduces the oxygen transmission rate of 0.127 mm poly(ethylene terephthalate) by two orders of magnitude, rivalling conventional oxygen barrier technologies. These films are fabricated in ambient conditions using low-cost, water-based solutions, providing a tremendous opportunity for single-step deposition of polymeric high barrier thin films. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. SnS thin films deposited by chemical bath deposition, dip coating and SILAR techniques

    NASA Astrophysics Data System (ADS)

    Chaki, Sunil H.; Chaudhary, Mahesh D.; Deshpande, M. P.

    2016-05-01

    The SnS thin films were synthesized by chemical bath deposition (CBD), dip coating and successive ionic layer adsorption and reaction (SILAR) techniques. In them, the CBD thin films were deposited at two temperatures: ambient and 70 °C. The energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and optical spectroscopy techniques were used to characterize the thin films. The electrical transport properties studies on the as-deposited thin films were done by measuring the I-V characteristics, DC electrical resistivity variation with temperature and the room temperature Hall effect. The obtained results are deliberated in this paper.

  3. Thin film zinc oxide deposited by CVD and PVD

    NASA Astrophysics Data System (ADS)

    Hamelmann, Frank U.

    2016-10-01

    Zinc oxide is known as a mineral since 1810, but it came to scientific interest after its optoelectronic properties found to be tuneable by p-type doping. Since the late 1980’s the number of publications increased exponentially. All thin film deposition technologies, including sol-gel and spray pyrolysis, are able to produce ZnO films. However, for outstanding properties and specific doping, only chemical vapor deposition and physical vapor deposition have shown so far satisfying results in terms of high conductivity and high transparency. In this paper the different possibilities for doping will be discussed, some important applications of doped ZnO thin films will be presented. The deposition technologies used for industrial applications are shown in this paper. Especially sputtering of aluminium doped Zinc Oxide (ZnO:Al or AZO) and LPCVD of boron doped Zinc Oxide (ZnO:B or BZO) are used for the commercial production of transparent conductive oxide films on glass used for thin film photovoltaic cells. For this special application the typical process development for large area deposition is presented, with the important trade-off between optical properties (transparency and ability for light scattering) and electrical properties (conductivity). Also, the long term stability of doped ZnO films is important for applications, humidity in the ambient is often the reason for degradation of the films. The differences between the mentioned materials are presented.

  4. Characterization of copper selenide thin films deposited by chemical bath deposition technique

    NASA Astrophysics Data System (ADS)

    Al-Mamun; Islam, A. B. M. O.

    2004-11-01

    A low-cost chemical bath deposition (CBD) technique has been used for the preparation of Cu2-xSe thin films onto glass substrates and deposited films were characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and UV-vis spectrophotometry. Good quality thin films of smooth surface of copper selenide thin films were deposited using sodium selenosulfate as a source of selenide ions. The structural and optical behaviour of the films are discussed in the light of the observed data.

  5. Reactive ion beam deposition of aluminum nitride thin films

    NASA Astrophysics Data System (ADS)

    Bhat, S.; Ashok, S.; Fonash, S. J.; Tongson}, L.

    1985-07-01

    Aluminum nitride thin films have been prepared at room temperature by reactive ion beam sputtering for potential use as a passivant and diffusion/anneal cap in compound semiconductor technology. The electrical and optical pro-perties of these films have been studied along with the in-fluence of thermal annealing on the material characteristics. The quality of the films has also been found to improve in the presence of atomic hydrogen during the deposition.

  6. Cubic Structure and Cation Disordering in Ybco Thin Film Deposited by High Speed Pulsed Laser Deposition

    NASA Astrophysics Data System (ADS)

    Suh, Jeong-Dae; Sung, Gun Yong; Kang, Kwang Yong

    We have investigated the crystalline structure of high rate deposited YBa2Cu3Ox thin films prepared by high speed pulsed laser deposition. A cation disordered cubic structure with lattice parameter of 0.39 nm was found in YBCO thin film deposited at 12.2 nm/s deposition rate and 650°C substrate temperature conditions. The short range ordered cubic YBa2Cu3Ox thin film growth at high deposition rate was explained by the short migration length of Y and Ba cation atoms owing to the high incident flux rate.

  7. Investigation of new stilbazolium dye thin films deposited by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Sotirov, S.; Todorova, M.; Draganov, M.; Penchev, P.; Bakalska, R.; Serbezov, V.

    2013-03-01

    In present work we report the analysis of thin films and targets from new stilbazolium dye E-4-(2-(4- hydroxynaphthalen-1-yl)vinyl)-1-octylquinolinium iodide (D1) deposited by Pulsed Laser Deposition (PLD) technique using high power UV TEA N2 laser. The thin films are deposited onto substrates - KBr, 316L SS alloy, optical glass and aluminum foil. The films were characterized by FTIR spectroscopy, bright field microscopy, fluorescence microscopy and atomic force microscopy (AFM) analysis. FTIR spectroscopic analysis of thin films and target material shows small differences between deposited films and native substance. The films are found to be homogeneous by AFM results and without any cracks and droplets on the surfaces. The present study demonstrates the ability of PLD technique to provide thin films from new stilbazolium dyes with good quality when they are applied as non-linear optical (NLO) organic materials on different type of substrates.

  8. Deposition of magnetoelectric hexaferrite thin films on substrates of silicon

    NASA Astrophysics Data System (ADS)

    Zare, Saba; Izadkhah, Hessam; Vittoria, Carmine

    2016-12-01

    Magnetoelectric M-type hexaferrite thin films (SrCo2Ti2Fe8O19) were deposited using Pulsed Laser Deposition (PLD) technique on Silicon substrate. A conductive oxide layer of Indium-Tin Oxide (ITO) was deposited as a buffer layer with the dual purposes of 1) to reduce lattice mismatch between the film and silicon and 2) to lower applied voltages to observe magnetoelectric effects at room temperature on Silicon based devices. The film exhibited magnetoelectric effects as confirmed by vibrating sample magnetometer (VSM) techniques in voltages as low as 0.5 V. Without the oxide conductive layer the required voltages to observe magnetoelectric effects was typically about 1000 times larger. The magnetoelectric thin films were characterized by X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy, vibrating sample magnetometer, and ferromagnetic resonance techniques. We measured saturation magnetization of 650 G, and coercive field of about 150 Oe for these thin films. The change in remanence magnetization was measured in the presence of DC voltages and the changes in remanence were in the order of 15% with the application of only 0.5 V (DC voltage). We deduced a magnetoelectric coupling, α, of 1.36×10-9 s m-1 in SrCo2Ti2Fe8O19 thin films.

  9. Anodization of Ti thin film deposited on ITO.

    PubMed

    Sadek, Abu Z; Zheng, Haidong; Latham, Kay; Wlodarski, Wojtek; Kalantar-Zadeh, Kourosh

    2009-01-06

    We have investigated several key aspects for the self-organization of nanotubes in RF sputtered titanium (Ti) thin films formed by the anodization process in fluoride-ion-containing neutral electrolytes. Ti films were deposited on indium tin oxide (ITO) glass substrates at room temperature and 300 degrees C, and then anodized. The films were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis spectrometry before and after anodization. It was observed that anodization of high temperature deposited films resulted in nanotube type structures with diameters in the range of 10-45 nm for an applied voltage of 5-20 V. In addition, the anatase form of TiO(2) is formed during the anodization process which is also confirmed using photocurrent measurements. However, the anodization of room temperature deposited Ti films resulted in irregular pores or holes.

  10. Sputter deposition for multi-component thin films

    DOEpatents

    Krauss, Alan R.; Auciello, Orlando

    1990-01-01

    Ion beam sputter-induced deposition using a single ion beam and a multicomponent target is capable of reproducibly producing thin films of arbitrary composition, including those which are close to stoichiometry. Using a quartz crystal deposition monitor and a computer controlled, well-focused ion beam, this sputter-deposition approach is capable of producing metal oxide superconductors and semiconductors of the superlattice type such as GaAs-AlGaAs as well as layered metal/oxide/semiconductor/superconductor structures. By programming the dwell time for each target according to the known sputtering yield and desired layer thickness for each material, it is possible to deposit composite films from a well-controlled sub-monolayer up to thicknesses determined only by the available deposition time. In one embodiment, an ion beam is sequentially directed via a set of X-Y electrostatic deflection plates onto three or more different element or compound targets which are constituents of the desired film. In another embodiment, the ion beam is directed through an aperture in the deposition plate and is displaced under computer control to provide a high degree of control over the deposited layer. In yet another embodiment, a single fixed ion beam is directed onto a plurality of sputter targets in a sequential manner where the targets are each moved in alignment with the beam under computer control in forming a multilayer thin film. This controlled sputter-deposition approach may also be used with laser and electron beams.

  11. Sputter deposition for multi-component thin films

    DOEpatents

    Krauss, A.R.; Auciello, O.

    1990-05-08

    Ion beam sputter-induced deposition using a single ion beam and a multicomponent target is capable of reproducibly producing thin films of arbitrary composition, including those which are close to stoichiometry. Using a quartz crystal deposition monitor and a computer controlled, well-focused ion beam, this sputter-deposition approach is capable of producing metal oxide superconductors and semiconductors of the superlattice type such as GaAs-AlGaAs as well as layered metal/oxide/semiconductor/superconductor structures. By programming the dwell time for each target according to the known sputtering yield and desired layer thickness for each material, it is possible to deposit composite films from a well-controlled sub-monolayer up to thicknesses determined only by the available deposition time. In one embodiment, an ion beam is sequentially directed via a set of X-Y electrostatic deflection plates onto three or more different element or compound targets which are constituents of the desired film. In another embodiment, the ion beam is directed through an aperture in the deposition plate and is displaced under computer control to provide a high degree of control over the deposited layer. In yet another embodiment, a single fixed ion beam is directed onto a plurality of sputter targets in a sequential manner where the targets are each moved in alignment with the beam under computer control in forming a multilayer thin film. This controlled sputter-deposition approach may also be used with laser and electron beams. 10 figs.

  12. Smoothing of mirror substrates by thin-film deposition

    SciTech Connect

    Baker, S; Parra, E; Spiller, E; Tarrio, C

    1999-08-03

    Superpolished optical flats with high spatial frequency roughness below 0.1 nm have been commercially available for years. However, it is much more difficult to obtain figured optics of similar quality. We have obtained and tested the finish of figured optics from different vendors by atomic force microscopy and optical profilometry and have investigated how the substrate quality can be improved by the deposition of thin films. We have determined the growth parameters of several thin-film structures. From these parameters we can determine how the surface topography of a coated mirror differs from that of the substrate, select the best thin-film structure, and predict the possible improvement. Keywords: Smoothing films, multilayer coatings, finish of mirror substrates

  13. Chemical Vapor Deposition of Aluminum Oxide Thin Films

    ERIC Educational Resources Information Center

    Vohs, Jason K.; Bentz, Amy; Eleamos, Krystal; Poole, John; Fahlman, Bradley D.

    2010-01-01

    Chemical vapor deposition (CVD) is a process routinely used to produce thin films of materials via decomposition of volatile precursor molecules. Unfortunately, the equipment required for a conventional CVD experiment is not practical or affordable for many undergraduate chemistry laboratories, especially at smaller institutions. In an effort to…

  14. Chemical Vapor Deposition of Aluminum Oxide Thin Films

    ERIC Educational Resources Information Center

    Vohs, Jason K.; Bentz, Amy; Eleamos, Krystal; Poole, John; Fahlman, Bradley D.

    2010-01-01

    Chemical vapor deposition (CVD) is a process routinely used to produce thin films of materials via decomposition of volatile precursor molecules. Unfortunately, the equipment required for a conventional CVD experiment is not practical or affordable for many undergraduate chemistry laboratories, especially at smaller institutions. In an effort to…

  15. Substrates suitable for deposition of superconducting thin films

    DOEpatents

    Feenstra, Roeland; Boatner, Lynn A.

    1993-01-01

    A superconducting system for the lossless transmission of electrical current comprising a thin film of superconducting material Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-x epitaxially deposited upon a KTaO.sub.3 substrate. The KTaO.sub.3 is an improved substrate over those of the prior art since the it exhibits small lattice constant mismatch and does not chemically react with the superconducting film.

  16. Sputter deposited Terfenol-D thin films for multiferroic applications

    NASA Astrophysics Data System (ADS)

    Mohanchandra, K. P.; Prikhodko, S. V.; Wetzlar, K. P.; Sun, W. Y.; Nordeen, P.; Carman, G. P.

    2015-09-01

    In this paper, we study the sputter deposition and crystallization process to produce high quality Terfenol-D thin film (100 nm) with surface roughness below 1.5 nm. The Terfenol-D thin film was produced using DC magnetron sputtering technique with various sputtering parameters and two different crystallization methods, i.e. substrate heating and post-annealing. Several characterization techniques including WDS, XRD, TEM, AFM, SQUID and MOKE were used to determine the physical and magnetic properties of the Terfenol-D films. TEM studies reveal that the film deposited on the heated substrate has large grains grown along the film thickness producing undesirable surface roughness while the film crystallized by post-annealing method shows uniformly distributed small grains producing a smooth surface. The Terfenol-D film was also deposited onto (011) cut PMN-PT single crystal substrate. With the application of an electric field the film exhibited a 1553 Oe change in coercivity with an estimated saturation magnetostriction of λs = 910 x 10-6.

  17. Pulsed laser deposition of anatase thin films on textile substrates

    NASA Astrophysics Data System (ADS)

    Krämer, André; Kunz, Clemens; Gräf, Stephan; Müller, Frank A.

    2015-10-01

    Pulsed laser deposition (PLD) is a highly versatile tool to prepare functional thin film coatings. In our study we utilised a Q-switched CO2 laser with a pulse duration τ ≈ 300 ns, a laser wavelength λ = 10.59 μm, a repetition frequency frep = 800 Hz and a peak power Ppeak = 15 kW to deposit crystalline anatase thin films on carbon fibre fabrics. For this purpose, preparatory experiments were performed on silicon substrates to optimise the anatase deposition conditions including the influence of different substrate temperatures and oxygen partial pressures. Processing parameters were then transferred to deposit anatase on carbon fibres. Scanning electron microscopy, X-ray diffraction analyses, Raman spectroscopy and tactile profilometry were used to characterise the samples and to reveal the formation of phase pure anatase without the occurrence of a secondary rutile phase. Methanol conversion test were used to prove the photocatalytic activity of the coated carbon fibres.

  18. Modified chemical route for deposition of molybdenum disulphide thin films

    SciTech Connect

    Vyas, Akshay N. Sartale, S. D.

    2014-04-24

    Molybdenum disulphide (MoS{sub 2}) thin films were deposited on quartz substrates using a modified chemical route. Sodium molybdate and sodium sulphide were used as precursors for molybdenum and sulphur respectively. The route involves formation of tetrathiomolybdate ions (MoS{sub 4}{sup 2−}) and further reduction by sodium borohydride to form MoS{sub 2}. The deposition was performed at room temperature. The deposited films were annealed in argon atmosphere at 1073 K for 1 hour to improve its crystallinity. The deposited films were characterized using scanning electron microscopy (SEM) for morphology, UV-Vis absorption spectroscopy for optical studies and X-ray diffraction (XRD) for structure determination.

  19. Stress development during deposition of CNx thin films

    NASA Astrophysics Data System (ADS)

    Broitman, E.; Zheng, W. T.; Sjöström, H.; Ivanov, I.; Greene, J. E.; Sundgren, J.-E.

    1998-05-01

    We have investigated the influence of deposition parameters on stress generation in CNx (0.3thin films deposited onto Si(001) substrates by reactive magnetron sputtering of C in pure N2 discharges. Film stress, σ, which in all cases is compressive, decreases with an increase in the N2 pressure, PN2, due to structural changes induced by the pressure-dependent variation in the average energy of particles bombarding the film during deposition. The film stress σ is also a function of the film growth temperature, Ts, and exhibits a maximum value of ˜5 GPa at 350 °C. Under these conditions, the films have a distorted microstructure consisting of a three-dimensional, primarily sp2 bonded, network. In contrast, films deposited at Ts<200 °C with a low stress are amorphous. At 350 °Cfilms grown at 350 °C exhibit the highest hardness and elasticity.

  20. Fundamental Mechanisms of Roughening and Smoothing During Thin Film Deposition

    SciTech Connect

    Headrick, Randall

    2016-03-18

    In this research program, we have explored the fundamental limits for thin film deposition in both crystalline and amorphous (i.e. non-crystalline) materials systems. For vacuum-based physical deposition processes such as sputter deposition, the background gas pressure of the inert gas (usually argon) used as the process gas has been found to be a key variable. Both a roughness transition and stress transition as a function of pressure have been linked to a common mechanism involving collisions of energetic particles from the deposition source with the process inert gas. As energetic particles collide with gas molecules in the deposition process they lose their energy rapidly if the pressure (and background gas density) is above a critical value. Both roughness and stress limit important properties of thin films for applications. In the area of epitaxial growth we have also discovered a related effect; there is a critical pressure below which highly crystalline layers grow in a layer-by-layer mode. This effect is also though to be due to energetic particle thermalization and scattering. Several other important effects such as the observation of coalescence dominated growth has been observed. This mode can be likened to the behavior of two-dimensional water droplets on the hood of a car during a rain storm; as the droplets grow and touch each other they tend to coalesce rapidly into new larger circular puddles, and this process proceeds exponentially as larger puddles overtake smaller ones and also merge with other large puddles. This discovery will enable more accurate simulations and modeling of epitaxial growth processes. We have also observed that epitaxial films undergo a roughening transition as a function of thickness, which is attributed to strain induced by the crystalline lattice mismatch with the substrate crystal. In addition, we have studied another physical deposition process called pulsed laser deposition. It differs from sputter deposition due to the

  1. Chemical vapor deposition and characterization of titanium dioxide thin films

    NASA Astrophysics Data System (ADS)

    Gilmer, David Christopher

    1998-12-01

    The continued drive to decrease the size and increase the speed of micro-electronic Metal-Oxide-Semiconductor (MOS) devices is hampered by some of the properties of the SiOsb2 gate dielectric. This research has focused on the CVD of TiOsb2 thin films to replace SiOsb2 as the gate dielectric in MOS capacitors and transistors. The relationship of CVD parameters and post-deposition anneal treatments to the physical and electrical properties of thin films of TiOsb2 has been studied. Structural and electrical characterization of TiOsb2 films grown from the CVD precursors tetraisopropoxotitanium (IV) (TTIP) and TTIP plus Hsb2O is described in Chapter 3. Both types of deposition produced stoichiometric TiOsb2 films comprised of polycrystalline anatase, but the interface properties were dramatically degraded when water vapor was added. Films grown with TTIP in the presence of Hsb2O contained greater than 50% more hydrogen than films grown using only TTIP and the hydrogen content of films deposited in both wet and dry TTIP environments decreased sharply with a post deposition Osb2 anneal. A significant thickness variation of the dielectric constant was observed which could be explained by an interfacial oxide and the finite accumulation thickness. Fabricated TiOsb2 capacitors exhibited electrically equivalent SiOsb2 gate dielectric thicknesses and leakage current densities as low as 38, and 1×10sp{-8} Amp/cmsp2 respectively. Chapter 4 discusses the low temperature CVD of crystalline TiOsb2 thin films deposited using the precursor tetranitratotitanium (IV), TNT, which produces crystalline TiOsb2 films of the anatase phase in UHV-CVD at temperatures as low as 184sp°C. Fabricated TiOsb2 capacitors exhibited electrically equivalent SiOsb2 gate dielectric thicknesses and leakage current densities as low as 17, and 1×10sp{-8} Amp/cmsp2 respectively. Chapter 5 describes the results of a comparison of physical and electrical properties between TiOsb2 films grown via LPCVD using

  2. X-ray reflectivity measurements of vacuum deposited thin films

    SciTech Connect

    Chason, M. ); Chason, E. )

    1992-01-01

    X-ray reflectivity using energy dispersive X-ray detection, a nondestructive probe of surface roughness over the region of [approximately] 1--50 [Angstrom], has been used to investigate the characteristicsof vacuum deposited thin films. With a surface roughness sensitivity better than 1 [Angstrom] X-ray reflectivity is sensitive to interfaces between different materials for sample thicknesses up to approximately2000 [Angstrom] (depending on material density). We have investigated discrete Cr/Al deposits on quartz substrates and determined the surface roughness at the interfaces. We have also monitored the evolution ofthe Cr/Al interface following annealing. The experimental data is presented and discussed. The use of the technique for studying thin film deposits is addressed.

  3. X-ray reflectivity measurements of vacuum deposited thin films

    SciTech Connect

    Chason, M.; Chason, E.

    1992-12-31

    X-ray reflectivity using energy dispersive X-ray detection, a nondestructive probe of surface roughness over the region of {approximately} 1--50 {Angstrom}, has been used to investigate the characteristicsof vacuum deposited thin films. With a surface roughness sensitivity better than 1 {Angstrom} X-ray reflectivity is sensitive to interfaces between different materials for sample thicknesses up to approximately2000 {Angstrom} (depending on material density). We have investigated discrete Cr/Al deposits on quartz substrates and determined the surface roughness at the interfaces. We have also monitored the evolution ofthe Cr/Al interface following annealing. The experimental data is presented and discussed. The use of the technique for studying thin film deposits is addressed.

  4. Thin Film Nanomorphology Tailored by Physical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Suzuki, Motofumi

    Shadowing growth by glancing angle deposition (GLAD) has been providing self-assembled nanostructures over much larger area for much lower costs since much earlier than the recent advanced top down processes do. In these two decades, significant progress has been made in the development of the well-controlled 3D nanomorphologies such as zigzag and helix. Much effort for theoretical and numerical understanding of the growth mechanism has been also paid in order to improve the morphology. Many researches in academia have been investigating useful properties of nanocolumnar thin films in their laboratory. On the other hand, most companies seem hesitate to introduce GLAD technique into the factory due to the prejudice that the obliquely deposited thin films are not durable and reproducible. In this article, we discuss the progress in glancing angle deposition technology for the practical applications.

  5. Low Temperature Chemical Vapor Deposition Of Thin Film Magnets

    DOEpatents

    Miller, Joel S.; Pokhodnya, Kostyantyn I.

    2003-12-09

    A thin-film magnet formed from a gas-phase reaction of tetracyanoetheylene (TCNE) OR (TCNQ), 7,7,8,8-tetracyano-P-quinodimethane, and a vanadium-containing compound such as vanadium hexcarbonyl (V(CO).sub.6) and bis(benzene)vanalium (V(C.sub.6 H.sub.6).sub.2) and a process of forming a magnetic thin film upon at least one substrate by chemical vapor deposition (CVD) at a process temperature not exceeding approximately 90.degree. C. and in the absence of a solvent. The magnetic thin film is particularly suitable for being disposed upon rigid or flexible substrates at temperatures in the range of 40.degree. C. and 70.degree. C. The present invention exhibits air-stable characteristics and qualities and is particularly suitable for providing being disposed upon a wide variety of substrates.

  6. Magnetic Phases of Sputter Deposited Thin-Film Erbium

    PubMed Central

    Witt, J. D. S.; Cooper, J. F. K.; Satchell, N.; Kinane, C. J.; Curran, P. J.; Bending, S. J.; Langridge, S.; Heyderman, L. J.; Burnell, G.

    2016-01-01

    We present a detailed structural and magnetic characterization of sputter deposited thin film erbium, determined by x-ray diffraction, transport measurements, magnetometry and neutron diffraction. This provides information on the onset and change of the magnetic state as a function of temperature and applied magnetic field. Many of the features of bulk material are reproduced. Also of interest is the identification of a conical magnetic state which repeats with a wavevector parallel to the c axis τc = 4/17 in units of the reciprocal lattice parameter c*, which is a state not observed in any other thin film or bulk measurements. The data from the various techniques are combined to construct magnetic field, temperature (H, T)–phase diagrams for the 200 nm-thick Er sample that serves as a foundation for future exploitation of this complex magnetic thin film system. PMID:27966662

  7. Magnetic Phases of Sputter Deposited Thin-Film Erbium

    NASA Astrophysics Data System (ADS)

    Witt, J. D. S.; Cooper, J. F. K.; Satchell, N.; Kinane, C. J.; Curran, P. J.; Bending, S. J.; Langridge, S.; Heyderman, L. J.; Burnell, G.

    2016-12-01

    We present a detailed structural and magnetic characterization of sputter deposited thin film erbium, determined by x-ray diffraction, transport measurements, magnetometry and neutron diffraction. This provides information on the onset and change of the magnetic state as a function of temperature and applied magnetic field. Many of the features of bulk material are reproduced. Also of interest is the identification of a conical magnetic state which repeats with a wavevector parallel to the c axis τc = 4/17 in units of the reciprocal lattice parameter c*, which is a state not observed in any other thin film or bulk measurements. The data from the various techniques are combined to construct magnetic field, temperature (H, T)-phase diagrams for the 200 nm-thick Er sample that serves as a foundation for future exploitation of this complex magnetic thin film system.

  8. Properties of zirconia thin films deposited by laser ablation

    SciTech Connect

    Cancea, V. N.; Filipescu, M.; Colceag, D.; Dinescu, M.; Mustaciosu, C.

    2013-11-13

    Zirconia thin films have been deposited by laser ablation of a ceramic ZrO{sub 2} target in vacuum or in oxygen background at 0.01 mbar. The laser beam generated by an ArF laser (λ=193 nm, ν=40 Hz) has been focalized on the target through a spherical lens at an incident angle of 45°. The laser fluence has been established to a value from 2.0 to 3.4 Jcm{sup −2}. A silicon (100) substrate has been placed parallel to the target, at a distance of 4 cm, and subsequently has been heated to temperatures ranging between 300 °C and 600 °C. Thin films morphology has been characterized by atomic force microscopy and secondary ion mass spectrometry. Biocompatibility of these thin films has been assessed by studying the cell attachment of L929 mouse fibroblasts.

  9. Microwave plasma assisted supersonic gas jet deposition of thin film materials

    DOEpatents

    Schmitt, III, Jerome J.; Halpern, Bret L.

    1993-01-01

    An apparatus for fabricating thin film materials utilizing high speed gas dynamics relies on supersonic free jets of carrier gas to transport depositing vapor species generated in a microwave discharge to the surface of a prepared substrate where the vapor deposits to form a thin film. The present invention generates high rates of deposition and thin films of unforeseen high quality at low temperatures.

  10. Luminescent sulfides and solution-deposited oxide thin films

    NASA Astrophysics Data System (ADS)

    Anderson, Jeremy T.

    Solid state luminescent sulfides are prepared as powders in order to elucidate the relationship between structure and light emission. While the sulfides studied in this dissertation are known phosphors, materials are investigated in a variety of new ways. Elementary properties and structures of MgS are reviewed, and preparation of MgS is described with sufficient detail that it may be reproduced in laboratories worldwide. Luminescence of MgS:Eu is evaluated, primarily by interpretation of published work. Solid pellets of MgS:Eu are created for the purpose of depositing thin-film layers by physical vapor deposition, and incorporating the phosphor layer within ACTFEL structures. Fabricated devices are found to exhibit bright ACTFEL luminescence--the brightest known for MgS. Similarly, MgS films are doped with a variety of lanthanide atoms to investigate the hot-electron distribution in MgS layers during device operation. The system BaGa2S4--SrGa 2S4 is evaluated for mutual solid phase solubility. Addition of Eu2+ causes each of these phases to photoluminescence. The emission energies (and therefore colors) are adjusted according to composition. Thin-film oxides are deposited from solution sources. Solution-deposited ZnO serves as the semiconductor layer in transparent thin-film transistor devices. A new class of dielectric material is also developed by solution methods. HafSOx and ZircSOx films, and derivative compositions, are evaluated in simple capacitor structures and demonstrated in functioning transistor devices. High-resolution nanolaminate structures are also constructed from this class of materials. From the knowledge and experience of developing oxide thin-films, more general chemical strategies are expressed.

  11. Thin NiTi Films Deposited on Graphene Substrates

    NASA Astrophysics Data System (ADS)

    Hahn, S.; Schulze, A.; Böhme, M.; Hahn, T.; Wagner, M. F.-X.

    2017-03-01

    We present experimental results on the deposition of Nickel Titanium (NiTi) films on graphene substrates using a PVD magnetron sputter process. Characterization of the 2-4 micron thick NiTi films by electron microscopy, electron backscatter diffraction, and transmission electron microscopy shows that grain size and orientation of the thin NiTi films strongly depend on the type of combination of graphene and copper layers below. Our experimental findings are supported by density functional theory calculations: a theoretical estimation of the binding energies of different NiTi-graphene interfaces is in line with the experimentally determined microstructural features of the functional NiTi top layer.

  12. Thin NiTi Films Deposited on Graphene Substrates

    NASA Astrophysics Data System (ADS)

    Hahn, S.; Schulze, A.; Böhme, M.; Hahn, T.; Wagner, M. F.-X.

    2016-12-01

    We present experimental results on the deposition of Nickel Titanium (NiTi) films on graphene substrates using a PVD magnetron sputter process. Characterization of the 2-4 micron thick NiTi films by electron microscopy, electron backscatter diffraction, and transmission electron microscopy shows that grain size and orientation of the thin NiTi films strongly depend on the type of combination of graphene and copper layers below. Our experimental findings are supported by density functional theory calculations: a theoretical estimation of the binding energies of different NiTi-graphene interfaces is in line with the experimentally determined microstructural features of the functional NiTi top layer.

  13. Liquid phase deposition synthesis of hexagonal molybdenum trioxide thin films

    SciTech Connect

    Deki, Shigehito; Beleke, Alexis Bienvenu; Kotani, Yuki; Mizuhata, Minoru

    2009-09-15

    Hexagonal molybdenum trioxide thin films with good crystallinity and high purity have been fabricated by the liquid phase deposition (LPD) technique using molybdic acid (H{sub 2}MoO{sub 4}) dissolved in 2.82% hydrofluoric acid (HF) and H{sub 3}BO{sub 3} as precursors. The crystal was found to belong to a hexagonal hydrate system MoO{sub 3}.nH{sub 2}O (napprox0.56). The unit cell lattice parameters are a=10.651 A, c=3.725 A and V=365.997 A{sup 3}. Scanning electron microscope (SEM) images of the as-deposited samples showed well-shaped hexagonal rods nuclei that grew and where the amount increased with increase in reaction time. X-ray photon electron spectroscopy (XPS) spectra showed a Gaussian shape of the doublet of Mo 3d core level, indicating the presence of Mo{sup 6+} oxidation state in the deposited films. The deposited films exhibited an electrochromic behavior by lithium intercalation and deintercalation, which resulted in coloration and bleaching of the film. Upon dehydration at about 450 deg. C, the hexagonal MoO{sub 3}.nH{sub 2}O was transformed into the thermodynamically stable orthorhombic phase. - Abstract: SEM photograph of typical h-MoO{sub 3}.nH{sub 2}O thin film nuclei obtained after 36 h at 40 deg. C by the LPD method. Display Omitted

  14. Characterization of electrophoretic suspension for thin polymer film deposition

    NASA Astrophysics Data System (ADS)

    Mladenova, D.; Weiter, M.; Stepanek, P.; Ouzzane, I.; Vala, M.; Sinigersky, V.; Zhivkov, I.

    2012-03-01

    The optical absorption and fluorescence spectra of poly [2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] toluene solutions and 50:50% toluene/acetonitrile suspensions show clearly distinguishable differences (e.g., peak broadening and shifting), which could be used for characterization of suspensions with different acetonitrile content. The dynamic light scattering (DLS) measurement of the suspensions prepared showed a particle size of 90 nm. Thin films with thicknesses of about 400 nm were prepared by electrophoretic deposition (EPD) and spin coating. As the films are very soft, a contactless optical profilometry techique based on chromatic aberration was used to measure their thickness. AFM imaging of spin coated and EPD films revealed film roughness of 20÷40 nm and 40÷80 nm, respectively. The EPD film roughness seems to be less than the suspension particle size obtained by DLS, probably due to the partial film dissolving by the toluene present in the suspension.

  15. Process and film characterization of chemical-bath-deposited ZnS thin films

    SciTech Connect

    Dona, J.M.; Herrero, J.

    1994-01-01

    Chemical-bath deposition of ZnS thin films from NH{sub 3}/NH{sub 2}-NH{sub 2}/SC(NH{sub 2}){sub 2}/ZnSO{sub 4} solutions has been studied. The effect of various process parameters on the growth and the film quality is presented. A first approach to a mechanistic interpretation of the chemical process is reported. The structural, optical, chemical, and electrical properties of the ZNS thin films deposited by this method have been studied. The electron diffraction (EDS) analysis shows that the films are microcrystalline with a cubic structure. EDS analysis has demonstrated that the films are highly stoichiometric. Scanning electron microscopy studies of the ZnS thin films deposited by this method show that the films are continuous and homogeneous. Electrical conductivity measurements have shown the highly resistivity nature of these films ({sigma} = 10{sup {minus}9} S/cm).

  16. Stress creation and relaxation during thin film deposition

    NASA Astrophysics Data System (ADS)

    Hearne, Sean Joseph

    This dissertation examines stress creation and relaxation processes associated with microstructural evolution during thin film deposition. Three materials systems were examined in this study; GaN on sapphire, AlGaN/GaN heterostructures, and Volmer-Weber films on amorphous substrates. In all three systems the stress during deposition was measured in situ in real-time, and the data was correlated with multiple ex situ analysis techniques. In the system GaN on sapphire, this work provided the first direct measure of the stress during metal organic chemical vapor deposition of GaN. It was determined that GaN films grew in tension during deposition, despite the compressive lattice mismatch with the sapphire substrate. A model based on the reduction of free volume associated with dislocation annihilation is presented that best accounts for the observed tensile stress. These studies of lattice-mismatched AlGaN/GaN epitaxial heterostructures focused on the energetics and kinetics of stress relaxation processes. It was determined that AlGaN on GaN relaxed via a combined brittle-ductile mode. The energetics of the stress relaxation was dictated by brittle failure since slip in AlGaN is very difficult. Evidence is presented that suggests that the localized shear stress concentrations around the crack tips promoted introduction of misfit dislocations within the AlGaN/GaN interface. The stress evolution in Volmer-Weber thin films deposited on amorphous substrates was also studied. This work focuses on Ag, Al, Ti, amorphous Si, and amorphous Ge thin films deposited on the native oxide of Si, which all displayed qualitatively similar stress evolution. The dynamic competition between stress generation due to island coalescence and capillarity, and stress relaxation due to Coble creep, interfacial sheer, and dewetting, was examined in detail. It was determined that interfacial shear dominates relaxation of weakly adherent Ag films, while relaxation in strongly adherent Al films

  17. Atomic layer deposition of superparamagnetic and ferrimagnetic magnetite thin films

    SciTech Connect

    Zhang, Yijun; Liu, Ming E-mail: wren@mail.xjtu.edu.cn Ren, Wei E-mail: wren@mail.xjtu.edu.cn; Zhang, Yuepeng; Chen, Xing; Ye, Zuo-Guang E-mail: wren@mail.xjtu.edu.cn

    2015-05-07

    One of the key challenges in realizing superparamagnetism in magnetic thin films lies in finding a low-energy growth way to create sufficiently small grains and magnetic domains which allow the magnetization to randomly and rapidly reverse. In this work, well-defined superparamagnetic and ferrimagnetic Fe{sub 3}O{sub 4} thin films are successfully prepared using atomic layer deposition technique by finely controlling the growth condition and post-annealing process. As-grown Fe{sub 3}O{sub 4} thin films exhibit a conformal surface and poly-crystalline nature with an average grain size of 7 nm, resulting in a superparamagnetic behavior with a blocking temperature of 210 K. After post-annealing in H{sub 2}/Ar at 400 °C, the as-grown α−Fe{sub 2}O{sub 3} sample is reduced to Fe{sub 3}O{sub 4} phase, exhibiting a ferrimagnetic ordering and distinct magnetic shape anisotropy. Atomic layer deposition of magnetite thin films with well-controlled morphology and magnetic properties provides great opportunities for integrating with other order parameters to realize magnetic nano-devices with potential applications in spintronics, electronics, and bio-applications.

  18. Pulsed laser deposition and characterizations of pyrochlore iridate thin films

    NASA Astrophysics Data System (ADS)

    Starr, Matthew; Aviles-Acosta, Jaime; Xie, Yuantao; Zhu, Wenka; Li, Zhen; Chen, Aiping; Li, Nan; Tao, Chenggang; Jia, Quanxi; Heremans, J. J.; Zhang, S. X.

    Pyrochlore iridates have attracted growing interest in recent years because of their potential to realize novel topological phases. While most of the previous studies have focused on polycrystalline and single crystalline bulk samples, epitaxial thin films offer a unique platform for controllable tuning of material parameters such as oxygen stoichiometry and elastic strain to achieve new electronic states. In this talk, we will present the growth and characterizations of epitaxial thin films of pyrochlore Y2Ir2O7 and Bi2Ir2O7 that are predicted to host topologically non-trivial states. The iridate thin films were grown by pulsed laser deposition at different conditions, and a narrow window for epitaxial growth was determined. Characterizations of crystalline structures were performed using X-ray diffraction and transmission electron microscopy to establish a growth parameter-structure phase diagram. The compositions of thin films were determined by energy dispersive X-ray spectroscopy, and the surface morphologies were characterized using atomic force microscopy and scanning tunneling microscopy. Magneto-transport studies indicate a strong dependence of transport properties on the oxygen stoichiometry and the film thickness.

  19. Formation of ultrasmooth thin silver films by pulsed laser deposition

    SciTech Connect

    Kuznetsov, I. A.; Garaeva, M. Ya.; Mamichev, D. A. Grishchenko, Yu. V.; Zanaveskin, M. L.

    2013-09-15

    Ultrasmooth thin silver films have been formed on a quartz substrate with a buffer yttrium oxide layer by pulsed laser deposition. The dependence of the surface morphology of the film on the gas (N{sub 2}) pressure in the working chamber and laser pulse energy is investigated. It is found that the conditions of film growth are optimal at a gas pressure of 10{sup -2} Torr and lowest pulse energy. The silver films formed under these conditions on a quartz substrate with an initial surface roughness of 0.3 nm had a surface roughness of 0.36 nm. These films can be used as a basis for various optoelectronics and nanoplasmonics elements.

  20. Chemically Deposited Thin-Film Solar Cell Materials

    NASA Technical Reports Server (NTRS)

    Raffaelle, R.; Junek, W.; Gorse, J.; Thompson, T.; Harris, J.; Hehemann, D.; Hepp, A.; Rybicki, G.

    2005-01-01

    We have been working on the development of thin film photovoltaic solar cell materials that can be produced entirely by wet chemical methods on low-cost flexible substrates. P-type copper indium diselenide (CIS) absorber layers have been deposited via electrochemical deposition. Similar techniques have also allowed us to incorporate both Ga and S into the CIS structure, in order to increase its optical bandgap. The ability to deposit similar absorber layers with a variety of bandgaps is essential to our efforts to develop a multi-junction thin-film solar cell. Chemical bath deposition methods were used to deposit a cadmium sulfide (CdS) buffer layers on our CIS-based absorber layers. Window contacts were made to these CdS/CIS junctions by the electrodeposition of zinc oxide (ZnO). Structural and elemental determinations of the individual ZnO, CdS and CIS-based films via transmission spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy and energy dispersive spectroscopy will be presented. The electrical characterization of the resulting devices will be discussed.

  1. Development of a Co-deposition method for Deposition of Low-Contamination Pyrite Thin Films

    NASA Astrophysics Data System (ADS)

    Walimbe, Aditya

    Pyrite is a 0.95 eV bandgap semiconductor which is purported to have great potential in widespread, low--cost photovoltaic cells. A thorough material selection process was used in the design of a pyrite sequential vapor deposition chamber aimed at reducing and possibly eliminating contamination during thin film growth. The design process focused on identifying materials that do not produce volatile components when exposed to high temperatures and high sulfur pressures. Once the materials were identified and design was completed, the ultra--high vacuum growth system was constructed and tested. Pyrite thin films were deposited using the upgraded sequential vapor deposition chamber by varying the substrate temperature from 250°C to 420°C during deposition, keeping sulfur pressure constant at 1 Torr. Secondary Ion Mass Spectrometry (SIMS) results showed that all contaminants in the films were reduced in concentration by orders of magnitude from those grown with the previous system. Characterization techniques of Rutherford Back--scattering Spectrometry (RBS), X--Ray Diffraction (XRD), Raman Spectroscopy, Optical Profilometry and UV/Vis/Near--IR Spectroscopy were performed on the deposited thin films. The results indicate that stoichiometric ratio of S:Fe, structural--quality (epitaxy), optical roughness and percentage of pyrite in the deposited thin films improve with increase in deposition temperature. A Tauc plot of the optical measurements indicates that the pyrite thin films have a bandgap of 0.94 eV.

  2. Nanoparticle formation and thin film deposition in aniline containing plasmas

    NASA Astrophysics Data System (ADS)

    Pattyn, Cedric; Dias, Ana; Hussain, Shahzad; Strunskus, Thomas; Stefanovic, Ilija; Boulmer-Leborgne, Chantal; Lecas, Thomas; Kovacevic, Eva; Berndt, Johannes

    2016-09-01

    This contribution deals with plasma based polymerization processes in mixtures of argon and aniline. The investigations are performed in a capacitively coupled RF discharge (in pulsed and continuous mode) and concern both the observed formation of nanoparticles in the plasma volume and the deposition of films. The latter process was used for the deposition of ultra-thin layers on different kind of nanocarbon materials (nanotubes and free standing graphene). The analysis of the plasma and the plasma chemistry (by means of mass spectroscopy and in-situ FTIR spectroscopy) is accompanied by several ex-situ diagnostics of the obtained materials which include NEXAFS and XPS measurements as well as Raman spectroscopy and electron microscopy. The decisive point of the investigations concern the preservation of the original monomer structure during the plasma polymerization processes and the stability of the thin films on the different substrates.

  3. Pulsed laser deposition and characterization of cellulase thin films

    NASA Astrophysics Data System (ADS)

    Cicco, N.; Morone, A.; Verrastro, M.; Viggiano, V.

    2013-08-01

    Thin films of cellulase were obtained by pulsed laser deposition (PLD) on an appropriate substrate. Glycoside hydrolase cellulase has received our attention because it emerges among the antifouling enzymes (enzymes being able to remove and prevent the formation of micro-organism biofilms) used in industry and medicine field. Pressed cellulase pellets, used as target material, were ablated with pulses of a Nd-YAG laser working at wavelength of 532 nm. In this work, we evaluated the impact of PLD technique both on molecular structure and hydrolytic activity of cellulase. Characteristic chemical bonds and morphology of deposited layers were investigated by FTIR spectroscopy and SEM respectively. The hydrolytic activity of cellulase thin films was detected by a colorimetric assay.

  4. Composition and structure of sputter deposited erbium hydride thin films

    SciTech Connect

    ADAMS,DAVID P.; ROMERO,JUAN A.; RODRIGUEZ,MARK A.; FLORO,JERROLD A.; BANKS,JAMES C.

    2000-05-10

    Erbium hydride thin films are grown onto polished, a-axis {alpha} Al{sub 2}O{sub 3} (sapphire) substrates by reactive ion beam sputtering and analyzed to determine composition, phase and microstructure. Erbium is sputtered while maintaining a H{sub 2} partial pressure of 1.4 x 10{sup {minus}4} Torr. Growth is conducted at several substrate temperatures between 30 and 500 C. Rutherford backscattering spectrometry (RBS) and elastic recoil detection analyses after deposition show that the H/Er areal density ratio is approximately 3:1 for growth temperatures of 30, 150 and 275 C, while for growth above {approximately}430 C, the ratio of hydrogen to metal is closer to 2:1. However, x-ray diffraction shows that all films have a cubic metal sublattice structure corresponding to that of ErH{sub 2}. RBS and Auger electron that sputtered erbium hydride thin films are relatively free of impurities.

  5. Deposition and characterization of aluminum magnesium boride thin film coatings

    NASA Astrophysics Data System (ADS)

    Tian, Yun

    Boron-rich borides are a special group of materials possessing complex structures typically comprised of B12 icosahedra. All of the boron-rich borides sharing this common structural unit exhibit a variety of exceptional physical and electrical properties. In this work, a new ternary boride compound AlMgB14, which has been extensively studied in bulk form due to its novel mechanical properties, was fabricated into thin film coatings by pulsed laser deposition (PLD) technology. The effect of processing conditions (laser operating modes, vacuum level, substrate temperature, and postannealing, etc.) on the composition, microstructure evolution, chemical bonding, and surface morphology of AlMgB14 thin film coatings has been investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectrometry; the mechanical, electrical, and optical properties of AlMgB14 thin films have been characterized by nanoindentation, four-point probe, van der Pauw Hall measurement, activation energy measurement, and UV-VIS-NIR spectrophotometer. Experimental results show that AlMgB14 films deposited in the temperature range of 300 K - 873 K are amorphous. Depositions under a low vacuum level (5 x 10-5 Torr) can introduce a significant amount of C and O impurities into AlMgB14 films and lead to a complex oxide glass structure. Orthorhombic AlMgB14 phase cannot be obtained by subsequent high temperature annealing. By contrast, the orthorhombic AlMgB 14 crystal structure can be attained via high temperature-annealing of AlMgB14 films deposited under a high vacuum level (< 3 x 10-6 Torr), accompanied by strong texture formation. Low vacuum level-as deposited AlMgB14 films have low hardness (10 GPa), but high vacuum level-as deposited AlMgB14 films exhibit an extremely high hardness (45 GPa - 51 GPa), and the higher deposition temperature results in still higher hardness

  6. Studies on atomic layer deposition of IRMOF-8 thin films

    SciTech Connect

    Salmi, Leo D. Heikkilä, Mikko J.; Vehkamäki, Marko; Puukilainen, Esa; Ritala, Mikko; Sajavaara, Timo

    2015-01-15

    Deposition of IRMOF-8 thin films by atomic layer deposition was studied at 260–320 °C. Zinc acetate and 2,6-naphthalenedicarboxylic acid were used as the precursors. The as-deposited amorphous films were crystallized in 70% relative humidity at room temperature resulting in an unknown phase with a large unit cell. An autoclave with dimethylformamide as the solvent was used to recrystallize the films into IRMOF-8 as confirmed by grazing incidence x-ray diffraction. The films were further characterized by high temperature x-ray diffraction (HTXRD), field emission scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), time-of-flight elastic recoil detection analysis (TOF-ERDA), nanoindentation, and energy-dispersive x-ray spectroscopy. HTXRD measurements revealed similar behavior to bulk IRMOF-8. According to TOF-ERDA and FTIR, composition of the films was similar to IRMOF-8. Through-porosity was confirmed by loading the films with palladium using Pd(thd){sub 2} (thd = 2,2,6,6-tetramethyl-3,5-heptanedionato) as the precursor.

  7. Electron Bombardment of Certain Thin Films during Deposition

    NASA Astrophysics Data System (ADS)

    Browning, Stephen Douglas

    The performance of multilayer thin film optical filters depends largely on the microstructure of the component layers. This microstructure varies with the deposition parameters inside the coating chamber. By controlling these parameters, optical filters can be produced to exacting specifications. In 1947, R. M. Rice established the technique of bombarding the substrate with electrons of several kilovolts as the fils were being deposited. This process improved the durability of zinc sulfide films dramatically. This study was performed to quantitatively analyze the effects of bombardment on film microstructure and subsequent effects on optical and mechanical properties. I installed an electron source filament inside the coating chamber and electrically isolated the substrate holder, which was connected to a positive high voltage supply. An accelerating loop placed just above the filament enhanced its efficiency. The source was calibrated by measuring the current through the substrate holder. Single layer films of five different materials were deposited, each at its own set of electron bombardment parameters. The microstructure was analyzed with an X -ray diffractometer and a transmission electron microscope. Optical properties were measured with guided waves, induced absorption, and spectrophotometric analysis. Film durability was analyzed with scotch tape, eraser, and controlled humidity tests. Antimony trioxide films showed a shift in lattice orientation, but this did not affect columnar structure or macroscopic quantities. Potassium hexafluorozirconate films showed elimination of both crystal structure and columnar growth, resulting in slightly reduced durability and some absorption. Silicon monoxide films suffered no change in structure or properties. Zinc sulfide films demonstrated the change in crystal structure, which was quantified and shown to improve moisture resistance. Optical properties were unaffected. Magnesium fluoride films showed a slight increase

  8. Titanium dioxide thin films by atomic layer deposition: a review

    NASA Astrophysics Data System (ADS)

    Niemelä, Janne-Petteri; Marin, Giovanni; Karppinen, Maarit

    2017-09-01

    Within its rich phase diagram titanium dioxide is a truly multifunctional material with a property palette that has been shown to span from dielectric to transparent-conducting characteristics, in addition to the well-known catalytic properties. At the same time down-scaling of microelectronic devices has led to an explosive growth in research on atomic layer deposition (ALD) of a wide variety of frontier thin-film materials, among which TiO2 is one of the most popular ones. In this topical review we summarize the advances in research of ALD of titanium dioxide starting from the chemistries of the over 50 different deposition routes developed for TiO2 and the resultant structural characteristics of the films. We then continue with the doped ALD-TiO2 thin films from the perspective of dielectric, transparent-conductor and photocatalytic applications. Moreover, in order to cover the latest trends in the research field, both the variously constructed TiO2 nanostructures enabled by ALD and the Ti-based hybrid inorganic-organic films grown by the emerging ALD/MLD (combined atomic/molecular layer deposition) technique are discussed.

  9. RESISTIVITY OF A THIN FILM DEPOSITED ON A CONDUCTIVE SUBSTRATE

    NASA Technical Reports Server (NTRS)

    Oberle, L. G.

    1994-01-01

    Resistivity of a Thin Film Deposited on a Conductive Substrate is a computer program developed to aid in the solution of the class of problems where resistivity measurements are needed for a substance deposited on a substrate of higher resistivity than the deposited layer. One of the ways in which a semiconductor material is characterized is by measurement of its resistivity. In the development of silicon carbide (SiC) for use as a semiconductor material for high temperature applications, it became necessary to measure the resistivity of the thin SiC film while it was still attached to the silicon upon which it had been grown epitaxially. The problem is that the presence of the silicon substrate will introduce error in the measured resistivity of the SiC. This program assumes that the resistivity of a thin film of conducting material deposited on another layer of conducting material is measured using the four-point probe. Using the four-point probe measurements, this program calculates the "true" resistivity of the deposited layer on a substrate of finite and different resistivity. Starting from basic principles, an expression for the ratio of measured voltage difference to injected current is developed. This expression involves the probe spacing, relative thicknesses of the layers, and the substrate resistivity as parameters, as well as the unknown resistivity of the deposited layer. The unknown resistivity can be found by iteratively evaluating the theoretical expression. This must be done numerically. The program is written in FORTRAN 77 and targeted for use on an IBM PC or compatible. It can be modified for use on any machine with a FORTRAN 77 compiler. It requires 46K of memory and has been implemented under MS-DOS 3.2.1. The program was developed in 1986.

  10. thin films prepared by pulsed laser deposition on different substrates

    NASA Astrophysics Data System (ADS)

    Navasery, M.; Halim, S. A.; Dehzangi, A.; Soltani, N.; Bahmanrokh, G.; Erfani H, M.; Kamalianfar, A.; Pan, K. Y.; Chang, S. C.; Chen, S. K.; Lim, K. P.; Awang Kechik, M. M.

    2014-09-01

    Perovskite manganite La2/3Ca1/3MnO3 thin films were directly grown on MgO(100), Si(100) and glass substrates by pulsed laser deposition. From the XRD patterns, the films are found to be polycrystalline, single-phase orthorhombic. The metal-insulator transition temperature is 209 K for LCMO/MgO, 266 K for LCMO/Si and 231 K for film deposited on the glass substrate. The conduction mechanism in these films is investigated in different temperature regimes. Low-temperature resistivity data below the phase transition temperature ( T P) have been fitted with the relation , indicating that the electron-electron scattering affects the conduction of these materials. The high-temperature resistivity data ( T > T P) were explained using variable-range hopping (VRH) and small-polaron hopping (SPH) models. Debye temperature values are 548 K for LCMO/Cg, 568 K for LCMO/Si and 508 K for LCMO/MgO thin films. In all thin films, the best fitting in the range of VRH is found for 3D dimension. The density of states near the Fermi level N ( E F) for LCMO/MgO is lower due to the prominent role of the grain boundary in LCMO/MgO and increase in bending of Mn-O-Mn bond angle, which decreases the double exchange coupling of Mn3+-O2-Mn4+ and in turn makes the LCMO/MgO sample less conducting as compared to the other films.

  11. Reactive sputter deposition of tungsten nitride thin films

    NASA Astrophysics Data System (ADS)

    Baker, Colin C.; Shah, S. Ismat

    2002-09-01

    Tungsten nitride (WNx) thin films were deposited by reactively sputtering a pure W target in an argon/nitrogen atmosphere. The nitrogen concentration in the growth chamber was varied from 2% to 60%. Film growth and properties were studied as a function of nitrogen concentration in the films. The cathode current and voltage variations during the film growth indicated cathode poisoning when the nitrogen concentration in the chamber was in the range of 2%-5%. This poisoning was accompanied by a reduced film growth rate. However, both the cathode current and deposition rate decrease were small due to the low resistivity and similar sputter yield of the WNx phase formed at the surface of the target and pure W. X-ray photoelectron spectroscopy analyses showed that the films were composed of approx33 at. % nitrogen when the nitrogen concentration in the chamber was greater than 10%. X-ray diffraction (XRD) analysis confirmed that the films were predominantly W2N with the characteristic (111) peak at 2theta]=37.7[deg. Slight shifts in the (111) peak position were due to excess nitrogen incorporation in interstitial positions, which caused lattice distortions. Postdeposition annealing removed the excess interstitial nitrogen and the XRD peaks shifted closer to the characteristic value. copyright 2002 American Vacuum Society.

  12. Pulsed laser deposition of compact high adhesion polytetrafluoroethylene thin films

    NASA Astrophysics Data System (ADS)

    Smausz, Tomi; Hopp, Béla; Kresz, Norbert

    2002-08-01

    Polytetrafluoroethylene (PTFE) thin films were prepared from pressed powder pellets via pulsed laser deposition by using ArF (193 nm) excimer laser. The applied laser fluences were in the 1.6-10 J cm-2 range, the substrate temperature was varied between 27°C and 250°C and post-annealing of the films was carried out in air at temperatures between 320°C and 500°C. Films deposited at 250°C substrate temperature were found to be stoichiometric while those prepared at lower temperatures were fluorine deficient. Morphological analyses proved that the film thickness did not significantly depend on the substrate temperature and the post annealing at 500°C resulted in a thickness reduction of approximately 50%. It was demonstrated that the films prepared at 8.2 J cm-2 fluence and annealed at 500°C followed by cooling at 1°C min-1 rate were compact, pinhole-free layers. The adherence of films to the substrates was determined by tensile strength measurements. Tensile strength values up to 2.4 MPa were obtained. These properties are of great significance when PTFE films are fabricated for the purpose of protecting coatings.

  13. Nanostructuring and texturing of pulsed laser deposited hydroxyapatite thin films

    NASA Astrophysics Data System (ADS)

    Kim, Hyunbin; Catledge, Shane; Vohra, Yogesh; Camata, Renato; Lacefield, William

    2003-03-01

    Hydroxyapatite (HA) [Ca_10(PO_4)_6(OH)_2] is commonly deposited onto orthopedic and dental metallic implants to speed up bone formation around devices, allowing earlier stabilization in a patient. Pulsed laser deposition (PLD) is a suitable means of placing thin HA films on these implants because of its control over stoichiometry, crystallinity, and nanostructure. These characteristics determine the mechanical properties of the films that must be optimized to improve the performance of load-bearing implants and other devices that undergo bone insertion. We have used PLD to produce nanostructured and preferentially oriented HA films and evaluated their mechanical properties. Pure, highly crystalline HA films on Ti-6Al-4V substrates were obtained using a KrF excimer laser (248nm) with energy density of 4-8 J/cm^2 and deposition temperature of 500-700^rcC. Scanning electron and atomic force microscopies reveal that our careful manipulation of energy density and substrate temperature has led to films made up of HA grains in the nanometer scale. Broadening of x-ray diffraction peaks as a function of deposition temperature suggests it may be possible to control the film nanostructure to a great extent. X-ray diffraction also shows that as the laser energy density is increased in the 4-8 J/cm^2 range, the hexagonal HA films become preferentially oriented along the c-axis perpendicular to the substrate. Texture, nanostructure, and phase make-up all significantly influence the mechanical properties. We will discuss how each of these factors affects hardness and Young's modulus of the HA films as measured by nanoindentation.

  14. Atomic layer deposition of thin superconducting films and multilayers

    NASA Astrophysics Data System (ADS)

    Proslier, Thomas; Klug, Jeffrey; Groll, Nikolas; Altin, Serdar; Becker, Nicholas

    2012-02-01

    We report the use of atomic layer deposition (ALD) to synthesize thin superconducting films and multilayer superconductor-insulator (S-I) heterostructures including: nitrides, carbides, and silicides, nitrides of molybdenum and titanium, and Nb1-xTixN/AlN-based S-I heterostructures. The atomic-scale thickness control afforded by ALD enables the study of superconductivity and associated phenomena in homogeneous layers in the ultra-thin film limit. Two-dimensional superconductivity in such films is of interest from a fundamental point of view, as a new effect has recently been discovered at ultra-low temperature in thin superconducting films made by ALD: the super-insulating transition. Furthermore, the ALD technique applied to superconducting films opens the way for a variety of applications, including improving the performance and decreasing the cost of high energy particle accelerators, superconducting wires for energy storage, and bolometers for radiation detection. In this respect, we will present results on the ALD growth processes, the metallurgy and superconducting properties of these coatings.

  15. Structural and optical properties of CZTS thin films deposited by ultrasonically assisted chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Zubair Ansari, Mohd; Khare, Neeraj

    2014-05-01

    Ultrasonically assisted chemical vapour deposition has been used for the deposition of thin films of Cu2ZnSnS4 (CZTS) on glass substrates. The effect of substrate temperature on the structural and optical properties of thin films has been investigated. The CZTS films show a tetragonal structure with preferential orientation along the (1 1 2) plane. X-ray diffraction and Raman studies confirm the formation of a single-phase CZTS film at a deposition temperature of 325 °C. These films show p-type semiconducting behaviour with a carrier concentration ˜1017 cm-3, optical absorption coefficient ˜104 cm-1 and direct optical band gap ˜1.4 eV. At higher substrate temperatures (⩾350 °C), secondary phases of Cu2-xS and SnS2 also start growing along with the CZTS phase. The band gap of CZTS films increases from 1.40 to 1.50 eV as the deposition temperature increases from 325 to 400 °C. The observed higher band gap for CZTS films deposited at 400 °C has been attributed to the growth of the Cu2-xS and SnS2 secondary phase and a sulfur-poor CZTS phase. The activation energy of the CZTS thin film deposited at 325 °C is 15 meV.

  16. YBCO thin film evaporation on as-deposited silver film on MgO

    NASA Astrophysics Data System (ADS)

    Azoulay, J.

    1999-11-01

    YBa 2Cu 3O 7- δ (YBCO) thin film was evaporated on as-deposited Ag buffer layer on MgO substrate. A simple, inexpensive vacuum system equipped with one resistively heated source was used. The subsequent heat treatment was carried out under low oxygen partial pressure at a relatively low temperature and short dwelling time. The films thus obtained were characterized for electrical properties using DC four-probe electrical measurements and inspected for structural properties and chemical composition by scanning electron microscopy (SEM). It is shown that YBCO thin film can grow on as-deposited thin silver layer on MgO substrate.

  17. Silicon nanomembranes as a means to evaluate stress evolution in deposited thin films

    Treesearch

    Anna M. Clausen; Deborah M. Paskiewicz; Alireza Sadeghirad; Joseph Jakes; Donald E. Savage; Donald S. Stone; Feng Liu; Max G. Lagally

    2014-01-01

    Thin-film deposition on ultra-thin substrates poses unique challenges because of the potential for a dynamic response to the film stress during deposition. While theoretical studies have investigated film stress related changes in bulk substrates, little has been done to learn how stress might evolve in a film growing on a compliant substrate. We use silicon...

  18. Biomimetic lithography and deposition kinetics of iron oxyhydroxide thin films

    SciTech Connect

    Rieke, P.C.; Wood, L.L.; Marsh, B.M.; Fryxell, G.E.; Engelhard, M.H.; Baer, D.R.; Tarasevich, B.J. |; John, C.M.

    1993-12-01

    Heterogeneous nucleation and crystal growth on functionalized organic substrates is a critical step in biological hard tissue formation. Self assembled monolayers can be derivatized with various organic functional groups to mimic the ``nucleation proteins`` for induction of mineral growth. Studies of nucleation and growth on SAMs can provide a better understanding of biomineralization and can also form the basis of a superior thin film deposition process. We demonstrate that micron-scale, electron and ion beam, lithographic techniques can be used to pattern SAMs with functional organic groups that either inhibit or promote mineral deposition. Patterned films of iron oxyhydroxide were deposited on the areas patterned with nucleation sites. Studies of the deposition kinetic of these films show that indeed the surface induces heterogeneous nucleation and that film formation does not occur via absorption of polymers or colloidal material formed homogeneously in solution. The nucleus interfacial free energy was calculated to be 24 mJ/m2 on a SAM surface composed entirely of sulfonate groups.

  19. Photochemical deposition of thin films from the metal hexacarbonyls

    SciTech Connect

    Singmaster K.A.; Houle, F.A.; Wilson, R.J. )

    1990-08-23

    Metal films grown by photolysis of Cr, Mo, and W hexacarbonyls are known to contain large amounts of carbon and oxygen, suggesting incomplete removal of CO from the precursor as well as possible reactions with other sources of carbon and oxygen. In order to identify microscopic processes responsible for film composition, a systematic study of thin films photochemically deposited by continuous, low-power 257-nm light from Cr, Mo, and W hexacarbonyls has been carried out. Since photodissociation of the precursor can occur on the surface as well as in the gas phase, experimental conditions have been chosen such that surface reaction kinetics are rate limiting. The experiments show that background gases during deposition and exposure of newly deposited films to air both result in significant oxidation of the films through their entire thickness, as determined by scanning Auger microscopy and sputter depth profiling. The results are discussed in terms of studies of photolysis of the metal hexacarbonyls and dissociative chemisorption of CO on clean crystalline metal surfaces.

  20. Microplasma deposition of challenging thin films at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Hopwood, Jeffrey; Thejaswini, H. C.; Plasma Engineering Laboratory Team

    2015-09-01

    Non-equilibrium microplasmas produce fluxes of ions and excited species to a surface while maintaining the surface near room temperature. At atmospheric pressure, however, it is very difficult to accelerate the highly collisional ions. While many applications do not benefit from energetic interactions between plasma and surface, conventional plasma deposition of thin films often requires either ion bombardment or substrate heating. For example, diamondlike carbon (DLC) is known to require ~ 100 eV ion bombardment and transparent conducting oxides (TCO) typically require substrate temperatures on the order of 400-500 K. A microwave-induced microplasma is used to dissociate dilute precursor molecules within flowing helium. The precursor and plasma species result in rapid deposition of thin films (>1 μm/min). This plasma produces a steady-state ion flux of 6×1017 cm-2s-1, which is more than two orders of magnitude greater than a low pressure capacitively coupled plasma. Likewise, the metastable density is roughly two orders greater. These and other microplasma diagnostics are correlated with the measured film properties of microplasma-deposited DLC and TCO. This study shows that high ion flux, even at low energy (~ 1 eV), can provide the needed surface interactions to produce these materials at room temperature.

  1. Ferrimagnetic thin films prepared by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Guyot, M.; Lisfi, A.; Krishnan, R.; Porte, M.; Rougier, P.; Cagan, V.

    1996-04-01

    Thin films, with thickness ranging from 25 nm up to 1.5 μm, of well-known ferrimagnetic materials such as NiFe 2O 4, CoFe 2O 4, Ni 0.5Zn 0.5Fe 2O 4, and BaFe 12O 19 have been prepared by PLD. Films made at low substrate temperature ( T < 500° C) are amorphous, but can crystallize by post-annealing in air in the temperature range 500-800°C. Films deposited at temperature between 500 and 800°C are polycrystalline, the grain size (from 50 nm to 1 μm) and surface roughness (1-100 nm) depending upon deposition parameters. The polycrystalline films are ferrimagnetic with a saturation magnetization close to the bulk value ( Js = 0.3 T for Ni-ferrites). Spinel films are isotropic as deduced from torque balance measurements. Coercivities are rather high for the spinel films (up to 500 Oe for Ni-ferrite) and even higher for the hexaferrites (3 kOe).

  2. Sub-picosecond laser deposition of thin films

    SciTech Connect

    Genin, F; Stuart, B; McLean, W; Chase, L

    2000-11-03

    The 1999 Nobel Prize in Chemistry recognized the importance and growing maturity of the femtosecond time-scale in science and engineering. Understanding the interaction between materials and high energy density light to manufacture and process materials has become a key issue in both programmatic and fundamental research at Lawrence Livermore National Laboratory. We have emphasized in this research the aspects related to producing thin films by ablation of material with intense ultra-short laser pulses. Our effort during FY2000 has been focused on building the foundation of this research using high purity graphite as the initial ablation material. We have deposited diamond-like carbon (DLC) in vacuum, measured ablation rates, and characterized the physical and chemical properties of the films. We successfully completed our first objective to compare the microstructure and materials properties of the films deposited using lasers operated in the femtosecond and nanosecond pulse length regime. The mechanical characterization of the deposits showed improved film-substrate adhesion properties that allowed us to build 200-{micro}m thick layers using 150 fs pulses. Films produced with ns-pulses delaminated as soon as the thickness reached only a couple of microns. The stresses in the films were greatly influenced by the fluence and the duration of the laser pulses. The microstructure and surface morphology of the films did not vary significantly with the processing parameters studied (pulse length and fluence). Finally, we demonstrated that it is possible to significantly increase the deposition rate with shorter pulses at a given fluence. In particular, carbon could be deposited at a rate of 25 {micro}m/hour with this technology. Our goal in FY2001 is to study and model the relationship between the ablation plume characteristics (energy, charge, mass, and momentum) and the film growth behavior in order to influence and optimize the deposition process. We also want to

  3. Zinc Oxide Thin Films Fabricated with Direct Current Magnetron Sputtering Deposition Technique

    SciTech Connect

    Hoon, Jian-Wei; Chan, Kah-Yoong; Krishnasamy, Jegenathan; Tou, Teck-Yong

    2011-03-30

    Zinc oxide (ZnO) is a very promising material for emerging large area electronic applications including thin-film sensors, transistors and solar cells. We fabricated ZnO thin films by employing direct current (DC) magnetron sputtering deposition technique. ZnO films with different thicknesses ranging from 100 nm to 1020 nm were deposited on silicon (Si) substrate. The deposition pressure was varied from 12 mTorr to 25 mTorr. The influences of the film thickness and the deposition pressure on structural properties of the ZnO films were investigated using Mahr surface profilometer and atomic force microscopy (AFM). The experimental results reveal that the film thickness and the deposition pressure play significant role in the structural formation of the deposited ZnO thin films. ZnO films deposited on Si substrates are promising for variety of thin-film sensor applications.

  4. Pulsed Nd:YAG laser deposition of ruthenium thin films

    NASA Astrophysics Data System (ADS)

    Wai Keat, Lee

    the Ru films were examined. Decreasing trend of resistivity was observed on the deposited Ru film with film thickness below 100 nm, while the increasing trend was observed above 100 nm Ru film. The lowest resistivity of the Ru thin film was found to be around 33 muO-cm. Droplets formation was detected on the surface of the Ru film through scanning electron microscopy (SEM) images. It was attributed to the effect of laser fluence modification on the Ru target surface during the deposition. The amount of droplets increased significantly above 4 J/cm 2. In this research work, the experimental threshold laser fluence is found to be around 4 J/cm2 where prominent observations such as increasing Ru I species and increasing droplets were obtained above this threshold. It is correlated well to the calculated theoretical threshold laser fluence which states that significant material removal and luminous plasma plume are expected.

  5. Optical thin films deposition by MDECR-PECVD

    NASA Astrophysics Data System (ADS)

    Haj Ibrahim, Bicher; Bulkin, Pavel; Daineka, Dmitri; Drévillon, Bernard

    2005-09-01

    We designed and built Matrix Distributed ECR (MDECR) PECVD reactor dedicated for dielectric filters deposition and equipped it with multiple sensors for process control. Planar matrix geometry of plasma source is based on electron cyclotron resonance effect at 2.45 GHz microwave frequency and provides scalability of the deposition on large area substrates. High (up to 5 nm/sec) deposition rate obtained due to high dissociation efficiency and careful design of the gas injection system. Optical emission spectroscopy, quadrupole mass-spectrometry and spectroscopic and multi-channel kinetic ellipsometry are installed for in-situ studies and control of the film deposition. We performed studies of the nature of high-density plasma discharge in silane, oxygen and nitrogen mixture and correlated its properties with optical and physical properties of deposited materials. To demonstrate the capabilities, a wide band gradient index antireflection coating on glass was realized by deposition of SiOxNy alloy thin films. The predefined variation of an index in a profile is obtained by changing the flows of precursors. Real-time control is performed with multi-channel kinetic ellipsometry.

  6. thin films by an hybrid deposition configuration: pulsed laser deposition and thermal evaporation

    NASA Astrophysics Data System (ADS)

    Escobar-Alarcón, L.; Solís-Casados, D. A.; Perez-Alvarez, J.; Romero, S.; Morales-Mendez, J. G.; Haro-Poniatowski, E.

    2014-10-01

    The aim of this work was to report the application of an hybrid deposition configuration to deposit Titanium dioxide (TiO2) thin films modified with different amounts of bismuth (Bi:TiO2). The samples were synthesized combining a TiO2 laser ablation plasma with a flux of vapor of bismuth produced by thermal evaporation. By varying the deposition rate of Bi it was possible to control the amount of Bi incorporated in the film and consequently the film properties. A detailed compositional, structural, and optical characterization by XPS, RBS, Raman spectroscopy, and UV-Vis spectrometry techniques is discussed. Photocatalytic response of the deposited thin films was studied through the degradation of a malachite green solution.

  7. Novel doped hydroxyapatite thin films obtained by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Duta, L.; Oktar, F. N.; Stan, G. E.; Popescu-Pelin, G.; Serban, N.; Luculescu, C.; Mihailescu, I. N.

    2013-01-01

    We report on the synthesis of novel ovine and bovine derived hydroxyapatite thin films on titanium substrates by pulsed laser deposition for a new generation of implants. The calcination treatment applied to produce the hydroxyapatite powders from ovine/bovine bones was intended to induce crystallization and to prohibit the transmission of diseases. The deposited films were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and energy dispersive X-ray spectroscopy. Pull-off adherence and profilometry measurements were also carried out. X-ray diffraction ascertained the polycrystalline hydroxyapatite nature of the powders and films. Fourier transform infrared spectroscopy evidenced the vibrational bands characteristic to a hydroxyapatite material slightly carbonated. The micrographs of the films showed a uniform distribution of spheroidal particulates with a mean diameter of ∼2 μm. Pull-off measurements demonstrated excellent bonding strength values between the hydroxyapatite films and the titanium substrates. Because of their physical-chemical properties and low cost fabrication from renewable resources, we think that these new coating materials could be considered as a prospective competitor to synthetic hydroxyapatite used for implantology applications.

  8. Reactive pulsed laser deposition of gold nitride thin films

    NASA Astrophysics Data System (ADS)

    Caricato, A. P.; Fernàndez, M.; Leggieri, G.; Luches, A.; Martino, M.; Romano, F.; Tunno, T.; Valerini, D.; Verdyan, A.; Soifer, Y. M.; Azoulay, J.; Meda, L.

    2007-07-01

    We report on the growth and characterization of gold nitride thin films on Si <1 0 0> substrates at room temperature by reactive pulsed laser ablation. A pure (99.95%) Au target was ablated with KrF excimer laser pulses in nitrogen containing atmosphere (N 2 or NH 3). The gas ambient pressure was varied in the range 0.1-100 Pa. The morphology of the films was studied by using optical, scanning electron and atomic force microscopy, evidencing compact films with RMS roughness in the range 3.6-35.1 nm, depending on the deposition pressure. Rutherford backscattering spectrometry and energy dispersion spectroscopy (EDS) were used to detect the nitrogen concentration into the films. The EDS nitrogen peak does not decrease in intensity after 2 h annealing at 250 °C. Film resistivity was measured using a four-point probe and resulted in the (4-20) × 10 -8 Ω m range, depending on the ambient pressure, to be compared with the value 2.6 × 10 -8 Ω m of a pure gold film. Indentation and scratch measurements gave microhardness values of 2-3 GPa and the Young's modulus close to 100 GPa. X-ray photoemission spectra clearly showed the N 1s peak around 400 eV and displaced with respect to N 2 phase. All these measurements point to the formation of the gold nitride phase.

  9. Optimization and testing of solid thin film lubrication deposition processes

    NASA Astrophysics Data System (ADS)

    Danyluk, Michael J.

    A novel method for testing solid thin films in rolling contact fatigue (RCF) under ultra-high vacuum (UHV) and high rotational speeds (130 Hz) is presented in this thesis. The UHV-RCF platform is used to quantify the adhesion and lubrication aspects of two thin film coatings deposited on ball-bearings using a physical vapor deposition ion plating process. Plasma properties during ion plating were measured using a Langmuir probe and there is a connection between ion flux, film stress, film adhesion, process voltage, pressure, and RCF life. The UHV-RCF platform and vacuum chamber were constructed using off-the-shelf components and 88 RCF tests in high vacuum have been completed. Maximum RCF life was achieved by maintaining an ion flux between 10 13 to 1015 (cm-2 s-1) with a process voltage and pressure near 1.5 kV and 15 mTorr. Two controller schemes were investigated to maintain optimal plasma conditions for maximum RCF life: PID and LQR. Pressure disturbances to the plasma have a detrimental effect on RCF life. Control algorithms that mitigate pressure and voltage disturbances already exist. However, feedback from the plasma to detect disturbances has not been explored related to deposition processes in the thin-film science literature. Manometer based pressure monitoring systems have a 1 to 2 second delay time and are too slow to detect common pressure bursts during the deposition process. Plasma diagnostic feedback is much faster, of the order of 0.1 second. Plasma total-current feedback was used successfully to detect a typical pressure disturbance associated with the ion plating process. Plasma current is related to ion density and process pressure. A real-time control application was used to detect the pressure disturbance by monitoring plasma-total current and converting it to feedback-input to a pressure control system. Pressure overshoot was eliminated using a nominal PID controller with feedback from a plasma-current diagnostic measurement tool.

  10. Microwave plasma assisted supersonic gas jet deposition of thin film materials

    DOEpatents

    Schmitt, J.J. III; Halpern, B.L.

    1993-10-26

    An apparatus for fabricating thin film materials utilizing high speed gas dynamics relies on supersonic free jets of carrier gas to transport depositing vapor species generated in a microwave discharge to the surface of a prepared substrate where the vapor deposits to form a thin film. The present invention generates high rates of deposition and thin films of unforeseen high quality at low temperatures. 5 figures.

  11. Multicomponent Nanostructured Thin Films. Deposition, Characterization, Testing and Application

    NASA Astrophysics Data System (ADS)

    Shtansky, D. V.

    The current topics related to the deposition, characterization, testing and application of tribological coatings are reviewed and refer to our recent results on nanostructured (Ti,Cr)-(Al,Si,Zr,Ca)-(C,B,N,O) thin films. The PVD targets based on the systems TiN+TiB2, TiB2+TiC, Ti5Si3+Ti, Ti5Si3+TiN, TiB2+Ti5Si3+Si, TiB2+Si, Ti5Si3+TiC, TiAl+TiC, TiB+Ti9Cr4B+Cr2Ti, CrB2, TiB2+TiAl+Ti2AlN, TiC+Ti3SiC2+TiSi2, TiC0.5+ZrO2, TiC0.5+CaO, Ti5Si3+ZrO2 were manufactured by means of self-propagating high-temperature synthesis (SHS). The BN and WSex films were deposited using a sintered hexagonal BN and a cold pressed WSe2 target, respectively. Multicomponent films were deposited by DC magnetron sputtering of composite targets either in an atmosphere of argon or reactively in a gaseous mixture of argon and nitrogen. The WSe2 films were deposited by PLD and ion-assisted PLD techniques. The microstructure and chemical composition of the films were studied by means of Auger electron spectroscopy (AES), energy-dispersive X-ray spectroscopy (EDXS), X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), high-resolution (HR) TEM, X-ray photoelectron spectroscopy (XPS), and electron energy-loss spectroscopy (EELS). The films were also characterized in terms of their hardness, elastic modulus, elastic recovery, adhesion, surface topography, friction and wear. Particular attention was paid to the analysis of the structure of the films in the nanometric scale and the evaluation of the properties of the individual nanostructures. Three groups of films are considered: 1) nanostructured hard, tribological coatings for civilian engineering Ti-B-N, Ti-Cr-B-N, Ti-Si-N, Ti-Al-B-N, Ti-Si-C-N, Ti-Si-B-N, BN and Cr-B-N; 2) double-layer self-lubricating coatings for civilian air force and space industry WSex/TiC, WSex/TiCN, WSex/TiSiN and 3) biocompatible coatings for medicine Ti-Ca-C-N-O, Ti-Zr-C-N-O, and Ti-Zr-Si-O-N.

  12. Jet vapor deposition of transparent conductive ZnO:Al thin films for photovoltaic applications

    SciTech Connect

    Han, H.; Zhang, J.Z.; Halpern, B.L.; Schmitt, J.J.; Cueto, J. del

    1996-12-31

    A novel, proprietary, and general approach to depositing thin films and coatings, The novel Jet Vapor Deposition{trademark} (JVD{trademark}) process is described, in which single or multiple jets in low vacuum are coupled with mobile substrates to generate a wide range of multicomponent, multilayer and host-guest thin films and coatings. Highly transparent and conducting aluminum-doped ZnO (ZnO:Al) thin films have been deposited at room temperature on glass slide, flexible polymer and thin film PV coated substrates by the JVD{sup TM} process. The thin films obtained from the optimized operating conditions have an average transmittance of about 85% in the visible range and electrical resistivities of 7 to 10 {times} 10{sup {minus}4} {Omega}-cm. Proper control of substrate bias, dopant content, deposition rate, and oxygen to metal ratio are the keys to depositing low resistivity and high transparency thin films.

  13. Short review on chemical bath deposition of thin film and characterization

    NASA Astrophysics Data System (ADS)

    Mugle, Dhananjay; Jadhav, Ghanshyam

    2016-05-01

    This reviews the theory of early growth of the thin film using chemical deposition methods. In particular, it critically reviews the chemical bath deposition (CBD) method for preparation of thin films. The different techniques used for characterizations of the chemically films such as X-ray diffractometer (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Electrical conductivity and Energy Dispersive Spectroscopy (EDS) are discussed. Survey shows the physical and chemical properties solely depend upon the time of deposition, temperature of deposition.

  14. Short review on chemical bath deposition of thin film and characterization

    SciTech Connect

    Mugle, Dhananjay Jadhav, Ghanshyam

    2016-05-06

    This reviews the theory of early growth of the thin film using chemical deposition methods. In particular, it critically reviews the chemical bath deposition (CBD) method for preparation of thin films. The different techniques used for characterizations of the chemically films such as X-ray diffractometer (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Electrical conductivity and Energy Dispersive Spectroscopy (EDS) are discussed. Survey shows the physical and chemical properties solely depend upon the time of deposition, temperature of deposition.

  15. Textured (100) yttria-stabilized zirconia thin films deposited by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Holzschuh, H.; Suhr, H.

    1991-07-01

    Thin films of yttria-stabilized zirconia were deposited by plasma-enhanced chemical vapor deposition on quartz Si(100), Si(111), Ni, and the steels V2A and Hastelloy at substrate temperatures (Ts): 673-873 K. The metal beta-diketonates Y (thd)3 and Zr(thd)4 were used as precursors. The fully stabilized fluorite-type cubic structure was obtained over a wide range of yttria contents from 3.5 to 80 mol pct (Ts = 773 K). The quality of the films depended on the match of the thermal expansion coefficients of substrate and deposit.

  16. Deposition of CdS thin films by chemical bath and photochemical deposition methods and its characterization

    NASA Astrophysics Data System (ADS)

    Kumar, V. Nirmal; Suriakarthick, R.; Shyju, T. S.; Gopalakrishnan, R.

    2013-06-01

    Cadmium sulfide nanocrystalline thin films were deposited by chemical bath and photochemical methods and their properties were studied. Cadmium sulfide thin films were deposited from aqueous solution, which contains cadmium sulfate pentahydrade and thiourea for chemical bath deposition and ammonia was used as a complexing agent, whereas in the photochemical deposition, the solution contains cadmium sulfate and sodium thiosulfate in appropriate concentration and CdS was deposited. The properties of the deposited Cadmium sulfide thin films were analyzed by XRD, SEM with EDX and Photoluminescence.

  17. Sputter-Deposited AlTiO Thin Films for Semi-Transparent Silicon Thin Film Solar Cells

    NASA Astrophysics Data System (ADS)

    Lee, Seung-Yun; Bang, Ki Su; Lim, Jung Wook

    2014-09-01

    This paper reports on sputter-deposited AlTiO (ATO) thin films and their effects on the performance of semi-transparent silicon thin film solar cells. The electrical resistivity and the transparency of the ATO films depend significantly on the flow ratio of oxygen to argon during the reactive sputtering process. With highly transparent ATO films, transmittances of over 80% were obtained by increasing this flow ratio. When the ATO films were used on silicon substrates, they exhibited an anti-reflection property, where the minimum reflectance at visible light wavelength was decreased to 1.2%. The introduction of ATO thin film layers into solar cells resulted in a 24% increase in transmittance at wavelengths of around 700 nm, due to the film's anti-reflection characteristic. In addition, the color of the cells changed from green to bright red as the ATO layers were adopted. These beneficial effects of the sputter-deposited ATO films suggest an effective pathway towards the semi-transparent silicon thin film solar cells for building-integrated photovoltaic system applications.

  18. Titanium dioxide thin films deposited by plasma enhanced atomic layer deposition for OLED passivation.

    PubMed

    Kim, Woong-Sun; Ko, Myoung-Gyun; Kim, Tae-Sub; Park, Sang-Kyun; Moon, Yeon-Keon; Lee, Su-Hwan; Park, Jae-Gun; Park, Jong-Wan

    2008-09-01

    Plasma enhanced atomic layer deposition (PEALD) of titanium dioxide thin films was conducted using Tetrakis dimethylamino titanium (TDMATi) and an oxygen plasma on a polyethersulfon (PES) substrate at a deposition temperature of 90 degrees C. The effects of the induced plasma power on passivation properties were investigated according to film thickness. The growth rate of the titanium dioxide film was 0.8 A/cycle, and the water vapor transmission rate (WTVR) for a 80 nm titanium dioxide film was 0.023 g/m2 day. The passivation performance of the titanium dioxide film was investigated using an organic light-emitting diode (OLED). The coated OLED lifetime was 90 h, 15 times longer than that of an uncoated sample.

  19. Deposition of Nanostructured Thin Film from Size-Classified Nanoparticles

    NASA Technical Reports Server (NTRS)

    Camata, Renato P.; Cunningham, Nicholas C.; Seol, Kwang Soo; Okada, Yoshiki; Takeuchi, Kazuo

    2003-01-01

    Materials comprising nanometer-sized grains (approximately 1_50 nm) exhibit properties dramatically different from those of their homogeneous and uniform counterparts. These properties vary with size, shape, and composition of nanoscale grains. Thus, nanoparticles may be used as building blocks to engineer tailor-made artificial materials with desired properties, such as non-linear optical absorption, tunable light emission, charge-storage behavior, selective catalytic activity, and countless other characteristics. This bottom-up engineering approach requires exquisite control over nanoparticle size, shape, and composition. We describe the design and characterization of an aerosol system conceived for the deposition of size classified nanoparticles whose performance is consistent with these strict demands. A nanoparticle aerosol is generated by laser ablation and sorted according to size using a differential mobility analyzer. Nanoparticles within a chosen window of sizes (e.g., (8.0 plus or minus 0.6) nm) are deposited electrostatically on a surface forming a film of the desired material. The system allows the assembly and engineering of thin films using size-classified nanoparticles as building blocks.

  20. Atomic layer deposition of nickel-cobalt spinel thin films.

    PubMed

    Hagen, D J; Tripathi, T S; Karppinen, M

    2017-04-05

    We report the atomic layer deposition (ALD) of high-quality crystalline thin films of the spinel-oxide system (Co1-xNix)3O4. These spinel oxides are ferrimagnetic p-type semiconductors, and promising material candidates for several applications ranging from photovoltaics and spintronics to thermoelectrics. The spinel phase is obtained for Ni contents exceeding the x = 0.33 limit for bulk samples. It is observed that the electrical resistivity decreases continuously with x while the magnetic moment increases up to x = 0.5. This is in contrast to bulk samples where a decrease of resistivity is not observed for x > 0.33 due to the formation of a rock-salt phase. From UV-VIS-NIR absorption measurements, a change from distinct absorption edges for the parent oxide Co3O4 to a continuous absorption band ranging deep into the near infrared for 0 < x ≤ 0.5 was observed. The conformal deposition of dense films on high-aspect-ratio patterns is demonstrated.

  1. Reaction network analysis for thin film deposition processes

    NASA Astrophysics Data System (ADS)

    Ramakrishnasubramanian, Krishnaprasath

    Understanding the growth of thin films produced by Atomic Layer Deposition (ALD) and Chemical Vapor Deposition (CVD) has been one of the most important challenge for surface chemists over the last two to three decades. There has been a lack of complete understanding of the surface chemistry behind these systems due to the dearth of experimental reaction kinetics data available. The data that do exist are generally derived through quantum computations. Thus, it becomes ever so important to develop a deposition model which not only predicts the bulk film chemistry but also explains its self-limiting nature and growth surface stability without the use of reaction rate data. The reaction network analysis tools developed in this thesis are based on a reaction factorization approach that aims to decouple the reaction rates by accounting for the chemical species surface balance dynamic equations. This process eliminates the redundant dynamic modes and identifies conserved modes as reaction invariants. The analysis of these invariants is carried out using a Species-Reaction (S-R) graph approach which also serves to simplify the representation of the complex reaction network. The S-R graph is self explanatory and consistent for all systems. The invariants can be easily extracted from the S-R graph by following a set of straightforward rules and this is demonstrated for the CVD of gallium nitride and the ALD of gallium arsenide. We propose that understanding invariants through these S-R graphs not only provides us with the physical significance of conserved modes but also give us a better insight into the deposition mechanism.

  2. Thin-film deposition and characterization for neutron detection applications

    NASA Astrophysics Data System (ADS)

    Misiano, C.; Trucchi, D. M.; Renzelli, M.; Bemporad, E.; Santoni, A.; Pietropaolo, A.; Vannozzi, A.; Celentano, G.

    2015-10-01

    Solid state physics experimental techniques and characterization tools can provide a valuable contribution to the research and development activity on He-free neutron detection systems, for both detector assessment and performance improvement. Presently, a He replacement strategy relies on the use of 6Li - and/or 10B -based neutron-to-charged particle converters coupled to radiation detectors (solid state, gaseous and scintillators). These topics have been discussed during a devoted session within the HeRe (He- Replacement) in Italy Workshop held in Frascati at the ENEA Research Centre, and this paper aims at presenting a brief overview on possible deposition and characterization techniques of thin films that have been subject of discussion.

  3. (abstract) Optical Scattering and Surface Microroughness of Ion Beam Deposited Au and Pt Thin Films

    NASA Technical Reports Server (NTRS)

    Al-Jumaily, Ghanim A.; Raouf, Nasrat A.; Edlou, Samad M.; Simons, John C.

    1994-01-01

    Thin films of gold and platinum have been deposited onto superpolished fused silica substrates using thermal evaporation, ion assisted deposition (IAD), and ion assisted sputtering. The influence of ion beam flux, thin film material, and deposition rate on the films microroughness have been investigated. Short range surface microroughness of the films has been examined using scanning tunneling microscopy (STM) and atomic force microscopy (AFM). Long range surface microroughness has been characterized using an angle resolved optical scatterometer. Results indicate that ion beam deposited coatings have improved microstructure over thermally evaporated films.

  4. Liquid phase deposition of silica: Thin films, colloids and fullerenes

    NASA Astrophysics Data System (ADS)

    Whitsitt, Elizabeth A.

    Little research has been done to explore liquid phase deposition (LPD) of silica on non-planar substrates. This thesis proves that the seeded growth of silica colloids from fullerene and surfactant micelles is possible via LPD, as is the coating of individual single walled carbon nanotubes (SWNTs) and carbon fibers. Working on the premise that a molecular growth mechanism (versus colloidal/gel deposition) is valid for LPD, nanostructured substrates and specific chemical functional groups should act as "seeds," or templates, for silica growth. Seeded growth is confirmed by reactions of the growth solution with a range of surfactants and with materials with distinctive surface moieties. LPD promises lower production costs and environmental impact as compared to present methods of coating technology, because it is an inherently simple process, using low temperatures and inexpensive air-stable reactants. Silica is ubiquitous in materials science. Its applications range from thixotropic additives for paint to gate dielectrics in the semiconductor industry. Nano-structured coatings and thin films are integral in today's electronics industry and will become more vital as the size of electronics shrinks. With the incorporation of nanoparticles in future devices, the ability to deposit quality coatings with finely tuned properties becomes paramount. The methods developed herein have applications in fabricating insulators for use in the future molecular scale electronics industry. Additionally, these silica nanoparticles have applications as templates for use in photonics and fuel cell membrane production and lend strength and durability to composites.

  5. Thin-film ferrites vapor deposited by one-step process in vacuum

    NASA Technical Reports Server (NTRS)

    Hacskaylo, M.

    1966-01-01

    Thin-film ferrites are formed by vapor deposition of a mixture of powdered ferrites and powdered boron oxide at controlled temperatures in a vacuum chamber. These films are used in memory devices for computers and as thin-film inductors in communications and telemetry systems.

  6. Aspects of thin film deposition on granulates by physical vapor deposition

    NASA Astrophysics Data System (ADS)

    Eder, Andreas; Schmid, Gerwin H. S.; Mahr, Harald; Eisenmenger-Sittner, Christoph

    2016-11-01

    Thin film and coating technology has entered fields which may show significant deviations from classical coating applications where films are deposited on plane, sometimes large substrates. Often surfaces of small and irregularly shaped bodies have to be improved in respect to electrical, thermal or mechanical properties. Film deposition and characterization on such small substrates is not a trivial task. This specially holds for methods based on Physical Vapor Deposition (PVD) processes such as sputter deposition and its ion- and plasma assisted varieties. Due to their line of sight nature a key issue for homogenous films is efficient intermixing. If this problem is mastered, another task is the prediction and determination of the film thickness on single particles as well as on large scale ensembles thereof. In this work a mechanism capable of uniformly coating up to 1000 cm3 of granulate with particle sizes ranging from approx. 10 μm to 150 μm by magnetron sputtering is thoroughly described. A method for predicting the average film thickness on the particles is presented and tested for several differently shaped objects like microspheres, irregular grains of sinter powder or micro diamonds. For assessing the film thickness on single particles as well as on particle ensembles several complementary methods based on optics, X-ray analysis and gravimetry are employed. Their respective merits and limitations are discussed. Finally an outlook on adapting the described technology for surface modification by plasma based reactive and non-reactive processes is given.

  7. Influence of Deposition Time on ZnS Thin Films Performance with Chemical Bath Deposition

    NASA Astrophysics Data System (ADS)

    Zhou, Limei; Tang, Nan; Wu, Sumei; Hu, Xiaofei; Xue, Yuzhi

    ZnS thin films had been deposited by chemical bath deposition method onto glass substrates in alkaline liquor. The reaction solution is made of ZnSO4, NH4OH and SC(NH2)2. Different deposition times (1 h, 1.5 h, 2 h, 2.5 h and 3 h) were selected to study the performance of ZnS thin films. As the results, the ZnS films' thickness were about 50-207 nm. XRD results showed an amorphous structure. Through comparing the surface morphology before and after annealing, it could be seen that annealing made some particles grow up and the surface smooth and even. The transmittance decreased with the increase of deposition time in the range of 300-800 nm. The transmittance of annealed ZnS film was lower than that of deposited one in the range of 300-800 nm. The ZnS band gap values were calculated in the range of 3.72-3.9 eV.

  8. Deposition of thermal and hot-wire chemical vapor deposition copper thin films on patterned substrates.

    PubMed

    Papadimitropoulos, G; Davazoglou, D

    2011-09-01

    In this work we study the hot-wire chemical vapor deposition (HWCVD) of copper films on blanket and patterned substrates at high filament temperatures. A vertical chemical vapor deposition reactor was used in which the chemical reactions were assisted by a tungsten filament heated at 650 degrees C. Hexafluoroacetylacetonate Cu(I) trimethylvinylsilane (CupraSelect) vapors were used, directly injected into the reactor with the aid of a liquid injection system using N2 as carrier gas. Copper thin films grown also by thermal and hot-wire CVD. The substrates used were oxidized silicon wafers on which trenches with dimensions of the order of 500 nm were formed and subsequently covered with LPCVD W. HWCVD copper thin films grown at filament temperature of 650 degrees C showed higher growth rates compared to the thermally ones. They also exhibited higher resistivities than thermal and HWCVD films grown at lower filament temperatures. Thermally grown Cu films have very uniform deposition leading to full coverage of the patterned substrates while the HWCVD films exhibited a tendency to vertical growth, thereby creating gaps and incomplete step coverage.

  9. Nanomechanical testing of thin composite layers - Application to Pd-In electrochemically deposited thin films

    NASA Astrophysics Data System (ADS)

    Chalakova, G.; Datcheva, M.; Zaharieva, R.; Georgiev, M.; Dobrovolska, Ts.; Stoychev, D.

    2015-10-01

    Pd-In thin films of various compositions were electrochemically deposited on brass substrates. Their mechanical properties (hardness and indentation modulus) were then determined using Nanoindenter G200 (Keysight Technologies) equipped with a sharp Berkovich tip. The main goal was to assess the effect of chemical and phase composition, as well as structure of the films, on the mechanical properties (indentation hardness and modulus) of the investigated Pd-In thin films regardless of the difference in the thickness and the significance of the surface roughness. It has been demonstrated that the mechanical properties of these films are highly compositionally sensitive, and the surface roughness yields scatter in the results and introduces uncertainty in the obtained mechanical characteristics.

  10. Nano-oxide thin films deposited via atomic layer deposition on microchannel plates.

    PubMed

    Yan, Baojun; Liu, Shulin; Heng, Yuekun

    2015-01-01

    Microchannel plate (MCP) as a key part is a kind of electron multiplied device applied in many scientific fields. Oxide thin films such as zinc oxide doped with aluminum oxide (ZnO:Al2O3) as conductive layer and pure aluminum oxide (Al2O3) as secondary electron emission (SEE) layer were prepared in the pores of MCP via atomic layer deposition (ALD) which is a method that can precisely control thin film thickness on a substrate with a high aspect ratio structure. In this paper, nano-oxide thin films ZnO:Al2O3 and Al2O3 were prepared onto varied kinds of substrates by ALD technique, and the morphology, element distribution, structure, and surface chemical states of samples were systematically investigated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoemission spectroscopy (XPS), respectively. Finally, electrical properties of an MCP device as a function of nano-oxide thin film thickness were firstly studied, and the electrical measurement results showed that the average gain of MCP was greater than 2,000 at DC 800 V with nano-oxide thin film thickness approximately 122 nm. During electrical measurement, current jitter was observed, and possible reasons were preliminarily proposed to explain the observed experimental phenomenon.

  11. Thin Film?

    NASA Astrophysics Data System (ADS)

    Kariper, İ. Afşin

    2014-09-01

    This study focuses on the critical surface tension of lead sulfite (PbSO3) crystalline thin film produced with chemical bath deposition on substrates (commercial glass).The PbSO3 thin films were deposited at room temperature at different deposition times. The structural properties of the films were defined and examined according to X-ray diffraction (XRD) and the XRD results such as dislocation density, average grain size, and no. of crystallites per unit area. Atomic force microscopy was used to measure the film thickness and the surface properties. The critical surface tension of the PbSO3 thin films was measured with an optical tensiometer instrument and calculated using the Zisman method. The results indicated that the critical surface tension of films changed in accordance with the average grain size and film thickness. The film thickness increased with deposition time and was inversely correlated with surface tension. The average grain size increased according to deposition time and was inversely correlated with surface tension.

  12. Annealing effect on Cu{sub 2}S thin films prepared by chemical bath deposition

    SciTech Connect

    More, Pawan; Dhanayat, Swapnali; Gattu, Ketan; Mahajan, Sandeep; Upadhye, Deepak; Sharma, Ramphal

    2016-05-06

    In present work Cu{sub 2}S thin film fabricated on glass substrate by simple, cost effective chemical bath deposition method subsequently it annealed at 150°C. These films were studied for their structural, optical and electrical properties using X-ray diffraction, UV-vis spectrophotometer and I-V system. The results show successful synthesis of Cu{sub 2}S thin films and improvement in crystalline nature of the thin film which resulted in reduced bad gap and resistance of the film. Thus these thin films prove to be a promising candidate for solar cell application.

  13. Development of vapor deposited thin films for bio-microsystems

    NASA Astrophysics Data System (ADS)

    Popat, Ketul Chandrakant

    Increasing demands for more biocompatible and sophisticated bio-microsystems in recent years has led to the development of a new technology called BioMEMS (biological micro-electro-mechanical systems). The foundation of this technology is the same as that of the traditional field of IC (integrated circuits), but an emphasis on developing new diagnostic and therapeutic modalities. Micro- and nano-fabrication techniques are currently being used to develop implants that can record, sense, stimulate and deliver to biological systems. Micromachined substrates can provide unique advantages over traditional implantable devices in terms of their ability to control surface micro-architecture, topography and feature size in micron and nano sizes. However, as BioMEMS technology is rapidly being developed, the practical use of these bio-microsystems is limited due to the inability to effectively interface with the biological system in non-immunogenic and stable manner. This is one of the most important considerations, and hence it is useful to focus on the fundamental scientific issues relating to material science, surface chemistry and immunology of silicon based bio-microsystems. This results in development of biomolecular interfaces that are compatible with both microfabrication processing and biological systems. The overall thrust of this research is to develop, characterize and integrate vapor deposited thin films with bio-microsystems in a manner that it is both reproducible and fully integrated with existing technologies. The main strategy is to use silane coatings precursor coatings on which poly (ethylene glycol) (PEG) will be coated in vapor phase. Silane has been coated user vapor phase, but its chemical and biological characterization and stability of the films under physiological conditions has not been investigated for biological applications. PEG has been coated in solution phase on silicon surface. However, it has not been coated under vapor phase. Here we are

  14. Highly Textured FeCo Thin Films Deposited by Low Temperature Pulsed Laser Deposition.

    PubMed

    Varvaro, Gaspare; Peddis, Davide; Barucca, Gianni; Mengucci, Paolo; Rodionova, Valeria; Chichay, Ksenia; Testa, Alberto Maria; Agostinelli, Elisabetta; Laureti, Sara

    2015-10-14

    The effect of the deposition temperature (Tdep) on the crystallographic orientation of pulsed laser-deposited FeCo/MgO(100) thin film was determined by means of X-ray reflectivity and high resolution trasmission electron microscopy analysis and was correlated with the magnetic anisotropy properties measured by angle dependent hysteresis loops. Highly textured films with a bcc structure and very smooth surface were obtained even at room temperature, the film being [100] and [110] oriented, at Tdep=25 °C and 150 °C, respectively. The cubic symmetry is reflected in the angular dependence of remanent magnetization, showing a 4-fold character, whose in-plane distribution is consistent with the different crystallographic orientations of the films. The high structural quality, even at room temperature, is reflected in a high value of the saturation magnetization and low coercivity, matching the requirements for technological applications.

  15. Macroparticles Reduction Using Filter Free Cathodic Vacuum Arc Deposition Method in ZnO Thin Films.

    PubMed

    Yuvakkumar, R; Peranantham, P; Nathanael, A Joseph; Nataraj, D; Mangalaraj, D; Hong, Sun Ig

    2015-03-01

    We report a new method to reduce macroparticles in ZnO thin films using filter free cathodic vacuum arc deposition without using any cooling arrangements operated at low arc current. The detailed mechanism has been proposed to reduce macroparticles during thin film deposition. The successful reduction of macroparticles was confirmed employing FESEM-EDX studies. FESEM images of ZnO thin films deposited with cathode spot to substrate distance from 10 to 20 cm revealed that the population of the macroparticles were reduced with the increase of cathode spot to substrate distances at low arc current. The prepared ZnO films were characterised and showed good structural and optical properties.

  16. The thin-film deposition of conjugated molecules for organic electronics

    NASA Astrophysics Data System (ADS)

    Jin, Michael H.-C.

    2008-06-01

    Device-quality conjugated organic thin films are now routinely prepared in many different ways to fabricate light-emitting diodes, thin-film transistors, and photovoltaic devices. Understanding how to design molecules through versatile synthetic chemistry and the mechanisms of phase transformation and chemical reaction that occur during the thin-film deposition process becomes especially vital for the performance of the applications. This article reviews the current understanding of various thin-film deposition technologies for the conjugated organic molecules primarily used in optoelectronics, particularly in photovoltaic applications.

  17. Enhanced Optical Absorption of Ti Thin Film: Coupled Effect of Deposition and Post-deposition Temperatures

    NASA Astrophysics Data System (ADS)

    Jaiswal, Jyoti; Mourya, Satyendra; Malik, Gaurav; Chauhan, Samta; Daipuriya, Ritu; Singh, Manpreet; Chandra, Ramesh

    2017-08-01

    In the present work, structural, morphological and optical properties of nanostructured titanium (Ti) thin films have been studied. The Ti thin films were fabricated on glass substrate by direct current (DC) magnetron sputtering at varying deposition and post-deposition temperatures (T DA) ranging from 373 K to 773 K. The microstructure and morphology of the Ti thin films were found to be highly dependent on T DA. The root mean square surface roughness (δ rms) was found to increase with T DA up to 673 K and then decreased at 773 K. The absorption (A) of Ti films has shown a similar trend as roughness with T DA; however, the reflection (R) has shown an opposite trend. Maximum A 99-86% and minimum R 1-14% were observed in the spectral range of 300-1100 nm for the sample fabricated at T DA = 673 K, which exhibited the highest δ rms 193 nm. Due to its excellent absorption, this film may be a potential candidate for photonic applications such as a super-absorber.

  18. Chemical vapor deposition and atomic layer deposition of metal oxide and nitride thin films

    NASA Astrophysics Data System (ADS)

    Barton, Jeffrey Thomas

    Processes for depositing thin films with various electronic, optical, mechanical, and chemical properties are indispensable in many industries today. Of the many deposition methods available, chemical vapor deposition (CVD) has proved over time to be one of the most flexible, efficient, and cost-effective. Atomic layer deposition (ALD) is a newer process that is gaining favor as a method for depositing films with excellent properties and unparalleled precision. This work describes the development of novel CVD and ALD processes to deposit a variety of materials. Hafnium oxide and zirconium oxide show promise as replacements for SiO 2 as gate dielectrics in future-generation transistors. These high-k materials would provide sufficient capacitance with layers thick enough to avoid leakage from tunneling. An ALD method is presented here for depositing conformal hafnium oxide from tetrakis-(diethylamido)hafnium and oxygen gas. A CVD method for depositing zirconium oxide from tetrakis-(dialkylamido)zirconium and either oxygen gas or water vapor is also described. The use of copper for interconnects in integrated circuits requires improved diffusion barrier materials, given its high diffusivity compared to the previously-used aluminum and tungsten. Tungsten nitride has a low resistivity among barrier materials, and can be deposited in amorphous films that are effective diffusion barriers in layers as thin as a few nanometers. Here we demonstrate CVD and plasma-enhanced CVD methods to deposit tungsten nitride films from bis-(dialkylamido)bis-( tert-butylimido)tungsten precursors and ammonia gas. Recent findings had shown uniform copper growth on tantalum silicate films, without the dewetting that usually occurs on oxide surfaces. Tantalum and tungsten silicates were deposited by a CVD reaction from the reaction of either tris-(diethylamido)ethylimido tantalum or bis-(ethylmethylamido)-bis-( tert-butylimido)tungsten with tris-(tert-butoxy)silanol. The ability of evaporated

  19. Effect of Deposition Temperature on the Properties of TIO2 Thin Films Deposited by Mocvd

    NASA Astrophysics Data System (ADS)

    Khalifa, Zaki S.

    2016-02-01

    Crystal structure, microstructure, and optical properties of TiO2 thin films deposited on quartz substrates by metal-organic chemical vapor deposition (MOCVD) in the temperature range from 250∘C to 450∘C have been studied. The crystal structure, thickness, microstructure, and optical properties have been carried out using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), atomic force microscope (AFM), and UV-visible transmittance spectroscopy, respectively. XRD patterns show that the obtained films are pure anatase. Simultaneously, the crystal size calculated using XRD peaks, and the grain size measured by AFM decrease with the increase in deposition temperature. Moreover, the texture of the films change and roughness decrease with the increase in deposition temperature. The spectrophotometric transmittance spectra have been used to calculate the refractive index, extinction coefficient, dielectric constant, optical energy gap, and porosity of the deposited films. While the refractive index and dielectric constant decrease with the increase of deposition temperature, the porosity shows the opposite.

  20. Thermochromic properties of Sn, W co-doped VO2 nanostructured thin film deposited by pulsed laser deposition.

    PubMed

    Hur, M G; Masaki, T; Yoon, D H

    2014-12-01

    Tin (Sn) and tungsten (W) co-doped vanadium dioxide (VO2) nanostructured thin films with 50-nm thickness were deposited by pulsed laser deposition (PLD) to reduce the transition temperature and improve the IR transmittance. The crystal structure of the nanostructured thin films and the presence of elements were evaluated by XRD and XPS analysis. The transition temperature (T(c)) of 1 at% Sn-1 at% W co-doped VO2 nanostructured thin film was decreased to about 22 degrees C (from 70.3 to 48.5 degrees C) compared with the undoped VO2 nanostructured thin film. The transmittance width in the IR range of the co-doped nanostructured thin film decreased from 37.5% to 27% compared with the undoped VO2 nanostructured thin film. Also, the width of hysteresis was narrowed by Sn doping.

  1. rf plasma oxidation of Ni thin films sputter deposited to generate thin nickel oxide layers

    SciTech Connect

    Hoey, Megan L.; Carlson, J. B.; Osgood, R. M. III; Kimball, B.; Buchwald, W.

    2010-10-11

    Nickel oxide (NiO) layers were formed on silicon (Si) substrates by plasma oxidation of nickel (Ni) film lines. This ultrathin NiO layer acted as a barrier layer to conduction, and was an integral part of a metal-insulator-metal (MIM) diode, completed by depositing gold (Au) on top of the oxide. The electrical and structural properties of the NiO thin film were examined using resistivity calculations, current-voltage (I-V) measurements and cross-sectional transmission electron microscopy (XTEM) imaging. The flow rate of the oxygen gas, chamber pressure, power, and exposure time and their influence on the characteristics of the NiO thin film were studied.

  2. Templated electrochemical deposition of zirconia thin films on "recordable CDs.".

    PubMed

    Yu, Hua-Zhong; Rowe, Aaron W; Waugh, Damien M

    2002-11-15

    In this paper, we describe a practical method of using gold films constructed from recordable compact disks (CD-Rs) as simple, inexpensive, and micropatterned conductive substrates for the fabrication of inorganic material microstructures. Extending from their application for the fabrication of self-assembled monolayers (SAMs) reported recently, bare and SAM-modified CD-R gold substrates have been used for template-directed electrodeposition of zirconia (ZrO2) thin films (i.e., the controlled formation of zirconia thin films on the different areas of the prefabricated, micrometer mountain-valley CD-R gold substrate surfaces). The present results demonstrate that the variation of the functional groups of the selected SAMs combined with electrodynamic control can be very successful to "customize" the formation and microstructure of functional inorganic thin films, which hold promise for modern technological applications.

  3. Thin-film preparation by back-surface irradiation pulsed laser deposition using metal powder targets

    NASA Astrophysics Data System (ADS)

    Kawasaki, Hiroharu; Ohshima, Tamiko; Yagyu, Yoshihito; Ihara, Takeshi; Yamauchi, Makiko; Suda, Yoshiaki

    2017-01-01

    Several kinds of functional thin films were deposited using a new thin-film preparation method named the back-surface irradiation pulsed laser deposition (BIPLD) method. In this BIPLD method, powder targets were used as the film source placed on a transparent target holder, and then a visible-wavelength pulsed laser was irradiated from the holder side to the substrate. Using this new method, titanium oxide and boron nitride thin films were deposited on the silicon substrate. Surface scanning electron microscopy (SEM) images suggest that all of the thin films were deposited on the substrate with some large droplets irrespective of the kind of target used. The deposition rate of the films prepared by using this method was calculated from film thickness and deposition time to be much lower than that of the films prepared by conventional PLD. X-ray diffraction (XRD) measurement results suggest that rutile and anatase TiO2 crystal peaks were formed for the films prepared using the TiO2 rutile powder target. Crystal peaks of hexagonal boron nitride were observed for the films prepared using the boron nitride powder target. The crystallinity of the prepared films was changed by annealing after deposition.

  4. Poly-para-xylylene thin films: A study of the deposition chemistry, kinetics, film properties, and film stability

    NASA Astrophysics Data System (ADS)

    Fortin, Jeffrey Bernard

    Poly-para-xylylene, or parylene, thin films are chemically vapor deposited (CVD), conformal, pin-hole free polymeric thin films. They have found many industrial uses since there invention in 1947 and continue to find new applications in micro-electronics, biotechnology, and micro-electro-mechanical systems. In this study the deposition chemistry, deposition kinetics, film properties, and film stability were investigated. A differentially pumped quadrupole mass spectrometer was used to analyze the vapor species present during the CVD process. The identity of dimer contamination and its impact on the CVD process and film properties was studied. The quantitative conversion of dimer to monomer was investigated and it was found that conversion begins at around 385°C and by 565°C 100% conversion is obtained. The kinetics of the CVD process was analyzed for a range of substrate temperatures and chamber pressures. A new kinetic model based on a two-step adsorption was developed and fit the kinetic data well. This model should be appropriate for use with all parylene family polymers. Many of the properties of the films deposited in this study were analyzed. This includes a detailed study of surface morphology using atomic force microscopy which shows the interface width increases as a power law of film thickness. Other properties analyzed were the thermal stability, electrical properties, index of refraction, birefringence, hardness, and elastic modulus. The effect of ultraviolet (UV) radiation of lambda ≥ 250 nm on the thermal stability, electrical, and optical properties of thin parylene films was studied. The thermal stability and electrical properties of UV treated films were seen to deteriorate as the radiation dose increased. The stability of parylene thin films receiving plasma etching was analyzed. The dielectric constant, dissipation factor, and leakage current of plasma etched thin parylene films were investigated and found to be stable for the range of

  5. Ln polyoxocations: yttrium oxide solution speciation & solution deposited thin films.

    PubMed

    Marsh, David A; Goberna-Ferrón, Sara; Baumeister, Mary K; Zakharov, Lev N; Nyman, May; Johnson, Darren W

    2017-01-17

    Rare earth oxide materials, including thin film coatings, are critically important in magnetic, luminescent and microelectric devices, and few substitutes have been discovered with comparable performance. Thin film coatings from solution are almost unknown for rare earth oxides, likely due to their high activity towards hydrolysis which yields poor quality thin films. The hexamer [Ln6(O)(OH)8(H2O)12(NO3)6](2+) is a rare example of a metal-oxo cluster isolated and stabilized without additional supporting organic ligands. Herein we report a new method for both the preparation and stabilization in non-aqueous media, which makes these clusters valuable precursors for solution-processed thin films. Solution characterization (NMR, small-angle X-ray scattering and Raman spectroscopy) in wet organic solvents indicated that the clusters evolve via a fragmentation and reaggregation process. This is especially true for hexamers of the smaller Ln(3+)-ions: the higher charge density yields higher hydration rates. This process produced an entirely new hexadecameric cluster formulated Y16O3(OH)24(NO3)18(OSMe2)16(OCMe2)2(H2O)4. The new structure represents an intermediate hydrolysis product on the pathway from hexanuclear clusters to metal oxyhydroxide bulk solid. DMSO solvent ligands displace aqua ligands on the cluster and likely explain the additional stability observed for these clusters in organic solvents. The enhanced cluster stability in DMF and DMSO also enables solution-processing methods to create high quality thin films.

  6. Carbon Nitride Thin Films Deposited by Cathodic Electrodeposition

    NASA Astrophysics Data System (ADS)

    Cao, Chuanbao; Fu, Jiyu; Zhu, Hesun

    Carbon nitride thin films were prepared by cathodic electrodeposition. The dicyandiamide compound dissovled in acetone was selected as the organic precursor. Single crystal silicon wafers and conductive glass (ITO) wafers were used as substrates. XPS measurements indicated that the films composed of carbon and nitrogen elements. The nitrogen content reached 41%. The polycrystalline β-C3N4 should exit in the prepared film from TED measurements. The nano hardness of the films on ITO substrates were as high as 13 GPa. The structure and properties were studies.

  7. Fabrication of Ultra-thin Color Films with Highly Absorbing Media Using Oblique Angle Deposition.

    PubMed

    Yoo, Young Jin; Lee, Gil Ju; Jang, Kyung-In; Song, Young Min

    2017-08-29

    Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.  We present an advanced method for fabricating ultra-thin color films with improved characteristics. The proposed process addresses several fabrication issues, including large area processing. Specifically, the protocol describes a process for fabricating ultra-thin color films using an electron beam evaporator for oblique angle deposition of germanium (Ge) and gold (Au) on silicon (Si) substrates.  Film porosity produced by the oblique angle deposition induces color changes in the ultra-thin film. The degree of color change depends on factors such as deposition angle and film thickness. Fabricated samples of the ultra-thin color films showed improved color tunability and color purity. In addition, the measured reflectance of the fabricated samples was converted into chromatic values and analyzed in terms of color. Our ultra-thin film fabricating method is expected to be used for various ultra-thin film applications such as flexible color electrodes, thin film solar cells, and optical filters. Also, the process developed here for analyzing the color of the fabricated samples is broadly useful for studying various color structures.

  8. HRTEM Microstructural Characterization of β-WO3 Thin Films Deposited by Reactive RF Magnetron Sputtering

    PubMed Central

    Faudoa-Arzate, A.; Arteaga-Durán, A.; Saenz-Hernández, R.J.; Botello-Zubiate, M.E.; Realyvazquez-Guevara, P.R.; Matutes-Aquino, J.A.

    2017-01-01

    Though tungsten trioxide (WO3) in bulk, nanosphere, and thin film samples has been extensively studied, few studies have been dedicated to the crystallographic structure of WO3 thin films. In this work, the evolution from amorphous WO3 thin films to crystalline WO3 thin films is discussed. WO3 thin films were fabricated on silicon substrates (Si/SiO2) by RF reactive magnetron sputtering. Once a thin film was deposited, two successive annealing treatments were made: an initial annealing at 400 °C for 6 h was followed by a second annealing at 350 °C for 1 h. Film characterization was carried out by X-ray diffraction (XRD), high-resolution electron transmission microscopy (HRTEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques. The β-WO3 final phase grew in form of columnar crystals and its growth plane was determined by HRTEM. PMID:28772559

  9. HRTEM Microstructural Characterization of β-WO3 Thin Films Deposited by Reactive RF Magnetron Sputtering.

    PubMed

    Faudoa-Arzate, A; Arteaga-Durán, A; Saenz-Hernández, R J; Botello-Zubiate, M E; Realyvazquez-Guevara, P R; Matutes-Aquino, J A

    2017-02-17

    Though tungsten trioxide (WO3) in bulk, nanosphere, and thin film samples has been extensively studied, few studies have been dedicated to the crystallographic structure of WO3 thin films. In this work, the evolution from amorphous WO3 thin films to crystalline WO3 thin films is discussed. WO3 thin films were fabricated on silicon substrates (Si/SiO2) by RF reactive magnetron sputtering. Once a thin film was deposited, two successive annealing treatments were made: an initial annealing at 400 °C for 6 h was followed by a second annealing at 350 °C for 1 h. Film characterization was carried out by X-ray diffraction (XRD), high-resolution electron transmission microscopy (HRTEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques. The β-WO3 final phase grew in form of columnar crystals and its growth plane was determined by HRTEM.

  10. Dependence of electro-optical properties on the deposition conditions of chemical bath deposited CdS thin films

    SciTech Connect

    Dona, J.M.; Herrero, J.

    1997-11-01

    Lately, there has been a sharp increase in the publication of papers on chemical bath deposition of CdS thin films and related materials due to successful results obtained using this method to fabricate CdS thin-film buffer layers for CuInSe{sub 2}- and CdTe-based polycrystalline thin-film solar cells. Generally, these papers focus on previously proposed methods of studying film characteristics without a systematic study of the influence of deposition conditions on film characteristics. In this paper the authors present an exhaustive study of the chemical bath-deposited CdS thin films electro-optical properties dependence on deposition variables. The authors propose not only a set of conditions for obtaining CdS thin films by this method but additionally, suitable deposition process conditions for certain application requirements, such as buffer layers for thin-film solar cells. The observed electro-optical characteristics dependence on the deposition variables corroborates the chemical mechanism that they proposed previously for this process.

  11. Ion Beam Deposition of Thin Films: Growth Processes and Nanostructure Formation

    SciTech Connect

    Hofsaess, Hans C.

    2004-12-01

    Ion beam deposition is a process far from thermodynamic equilibrium and is in particular suited to grow metastable thin films with diamond-like properties, such as tetrahedral amorphous carbon (ta-C) and cubic boron nitride (c-BN). In this contribution the atomistic description of the deposition and growth processes are reviewed and compared to experimental results, obtained from mass selected ion beam deposition. The focus will be set to the nucleation and growth processes of boron nitride as a model system for ion based thin film formation. Furthermore, recent examples for nanostructure formation in ion deposited compound thin films will be presented. Ion beam deposited metal-carbon nano-composite thin films exhibit a variety of different morphologies such as rather homogeneous nanocluster distributions embedded in an a-C matrix, but also the self-organized formation of nanoscale multilayer structures.

  12. PbTe thin films grown by femtosecond pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Rodriguez, E.; Silva, D.; Moya, L.; Cesar, C. L.; Barbosa, L. C.; Schrank, A.; Souza Filho, C. R.; de Oliveira, E. P.

    2007-09-01

    PbTe thin films were grown on BK7 glass and Si(100) substrates using femtosecond pulsed laser deposition at room temperature. The influence of the background pressure and the laser fluence on the structural and optical characteristics of the PbTe films was studied. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the surface and structural properties of the deposited PbTe thin films, respectively. Transmission spectroscopy measurements in the visible and infrared region (VIS-IR) were used to investigate the optical properties of the PbTe thin films.

  13. High-resolution photometric optical monitoring for thin-film deposition.

    PubMed

    Rabady, Rabi; Zinoviev, Kirill; Avrutsky, Ivan

    2004-01-01

    Real-time monitoring of thin-film deposition with high resolution is important for precise fabrication of thin-film devices in a technological environment with ever-increasing demands for smaller size and better performance. Using photometry, we were able to achieve a real-time optical monitoring resolution of film thickness that is comparable with a single atomic layer scale (i.e., subnanometer). Filtering noise efficiently and compensating for sources of error by use of an appropriate model produced this high resolution. The procedure proved reliable and can be useful in the thin-film-deposition industry.

  14. Induced Recrystallization of CdTe Thin Films Deposited by Close-Spaced Sublimation

    SciTech Connect

    Moutinho, H. R.; Dhere, R. G.; Al-Jassim, M. M.; Levi, D. H.; Kazmerski, L. L.; Mayo, B.

    1998-10-26

    We have deposited CdTe thin films by close-spaced sublimation at two different temperature ranges. The films deposited at the lower temperature partially recrystallized after CdCl2 treatment at 350 C and completely recrystallized after the same treatment at 400 C. The films deposited at higher temperature did not recrystallize at these two temperatures. These results confirmed that the mechanisms responsible for changes in physical properties of CdTe films treated with CdCl2 are recrystallization and grain growth, and provided an alternative method to deposit CSS films using lower temperatures.

  15. Pulse laser deposited nanostructured ZnO thin films: a review.

    PubMed

    Kumar, Rajesh; Kumar, Girish; Umar, Ahmad

    2014-02-01

    This review summarizes the work principles of pulse laser deposition (PLD) apparatus, physical processes like ablation, and plasma plume formation accompanying the deposition of un-doped ZnO from target to substrate material. Various modes of deposition and factors influencing the properties of thin films such as substrate temperature, background gas pressure, laser energy density (laser fluence), target to substrate distance, repetition rate, oxygen partial pressure in deposition chamber, deposition time and post growth annealing which control deposition parameters such as adsorption, desorption, surface diffusion, nucleation, and crystallization/re-crystallization are also discussed in this review. Moreover, various film properties such as morphology, roughness of the film surface, film thickness, grain size, optical transmittance, sensitivity, electrical conductivity, uniformity and electrical resistivity of the deposited ZnO thin films have also been enumerated in the present review.

  16. Biocompatibility of atomic layer-deposited alumina thin films.

    PubMed

    Finch, Dudley S; Oreskovic, Tammy; Ramadurai, Krishna; Herrmann, Cari F; George, Steven M; Mahajan, Roop L

    2008-10-01

    Presented in this paper is a study of the biocompatibility of an atomic layer-deposited (ALD) alumina (Al2O3) thin film and an ALD hydrophobic coating on standard glass cover slips. The pure ALD alumina coating exhibited a water contact angle of 55 degrees +/- 5 degrees attributed, in part, to a high concentration of -OH groups on the surface. In contrast, the hydrophobic coating (tridecafluoro-1,1,2,2-tetrahydro-octyl-methyl-bis(dimethylamino)silane) had a water contact angle of 108 degrees +/- 2 degrees. Observations using differential interference contrast microscopy on human coronary artery smooth muscle cells showed normal cell proliferation on both the ALD alumina and hydrophobic coatings when compared to cells grown on control substrates. These observations suggested good biocompatibility over a period of 7 days in vitro. Using a colorimetric assay technique to assess cell viability, the cellular response between the three substrates can be differentiated to show that the ALD alumina coating is more biocompatible and that the hydrophobic coating is less biocompatible when compared to the control. These results suggest that patterning a substrate with hydrophilic and hydrophobic groups can control cell growth. This patterning can further enhance the known advantages of ALD alumina, such as conformality and excellent dielectric properties for bio-micro electro mechanical systems (Bio-MEMS) in sensors, actuators, and microfluidics devices.

  17. A direct solution deposition approach to CdTe thin films

    SciTech Connect

    Miskin, Caleb K.; Dubois-Camacho, Angela; Reese, Matthew O.; Agrawal, Rakesh

    2016-01-01

    A direct solution deposition approach to CdTe thin films is presented. The difficulty of co-dissolving Te and desirable Cd salts is overcome through a diamine-thiol solvent mixture. Thin films of densely-packed, micron-sized grains are achieved after annealing without the need for chalcogen or CdCl2 vapor treatments.

  18. RESEARCH ON THE DEPOSITION OF MAGNETIC INTERMETALLIC COMPOUNDS IN THIN FILMS.

    DTIC Science & Technology

    A process for the vacuum deposition of thin films of intermetallic compounds of cobalt and yttrium, samarium, or neodymium, was developed. The...of the evaporation rates. Thin films of the desired stoichiometric compositions, Co5R, were produced in an extensive series of sequential experiments

  19. Microstructural and Electrical Characterization of Barium Strontium Titanate-Based Solid Solution Thin Films Deposited on Ceramic Substrates by Pulsed Laser Deposition

    DTIC Science & Technology

    2003-04-03

    Strontium Titanate-Based Solid Solution Thin Films Deposited on Ceramic Substrates by Pulsed Laser Deposition DISTRIBUTION: Approved for public...Society H2.4 Microstructural and Electrical Characterization of Barium Strontium Titanate- based Solid Solution Thin Films Deposited on Ceramic...investigated and report the microstructural and electrical characterization of selected barium strontium titanate-based solid solution thin films

  20. Deposition of thermoelectric strontium hexaboride thin films by a low pressure CVD method

    NASA Astrophysics Data System (ADS)

    Tynell, Tommi; Aizawa, Takashi; Ohkubo, Isao; Nakamura, Katsumitsu; Mori, Takao

    2016-09-01

    Thin films of SrB6 were deposited on sapphire substrates using a chemical vapor deposition method, with elemental strontium and decaborane, B10H14, used as the strontium and boron sources, respectively. The formation of highly crystalline, phase-pure SrB6 films was confirmed with X-ray diffraction and reflection high energy diffraction (RHEED) analysis, and the films' thermoelectric transport properties were measured. A relatively high deposition temperature of 850-950 °C was found to be optimal for obtaining well-crystallized films at an extremely high deposition rate. The thermoelectric transport properties of the SrB6 thin films were observed to be comparable to those reported for bulk materials, but an unexpectedly high electrical resistivity led to a reduced power factor value for the thin films.

  1. Properties of ITO thin films deposited on amorphous and crystalline substrates with e-beam evaporation

    NASA Astrophysics Data System (ADS)

    Wang, R. X.; Beling, C. D.; Djurisic, A. B.; Li, S.; Fung, S.

    2004-06-01

    Indium tin oxide (ITO) thin films were deposited using the e-beam evaporation method on amorphous and crystalline substrates under identical conditions. The properties of the films were investigated using optical transmittance, XRD and XPS techniques. It was found that the properties of the films depend strongly on the nature of the substrate surface. Analysis suggests that changes in chemical composition and microstructure of the ITO films deposited on crystalline and amorphous substrates are responsible for the differences in optical properties.

  2. Spectroscopic ellipsometry investigations of optical anisotropy in obliquely deposited hafnia thin films

    SciTech Connect

    Tokas, R. B. Jena, Shuvendu; Thakur, S.; Sahoo, N. K.; Haque, S. Maidul; Rao, K. Divakar

    2016-05-23

    In present work, HfO{sub 2} thin films have been deposited at various oblique incidences on Si substrates by electron beam evaporation. These refractory oxide films exhibited anisotropy in refractive index predictably due to special columnar microstructure. Spectroscopic ellipsometry being a powerful tool for optical characterization has been employed to investigate optical anisotropy. It was observed that the film deposited at glancing angle (80°) exhibits the highest optical anisotropy. Further, anisotropy was noticed to decrease with lower values of deposition angles while effective refractive index depicts opposite trend. Variation in refractive index and anisotropy has been explained in light of atomic shadowing during growth of thin films at oblique angles.

  3. Ultraviolet optical properties of aluminum fluoride thin films deposited by atomic layer deposition

    SciTech Connect

    Hennessy, John Jewell, April D.; Balasubramanian, Kunjithapatham; Nikzad, Shouleh

    2016-01-15

    Aluminum fluoride (AlF{sub 3}) is a low refractive index material with promising optical applications for ultraviolet (UV) wavelengths. An atomic layer deposition process using trimethylaluminum and anhydrous hydrogen fluoride has been developed for the deposition of AlF{sub 3} at substrate temperatures between 100 and 200 °C. This low temperature process has resulted in thin films with UV-optical properties that have been characterized by ellipsometric and reflection/transmission measurements at wavelengths down to 200 nm. The optical loss for 93 nm thick films deposited at 100 °C was measured to be less than 0.2% from visible wavelengths down to 200 nm, and additional microstructural characterization demonstrates that the films are amorphous with moderate tensile stress of 42–105 MPa as deposited on silicon substrates. X-ray photoelectron spectroscopy analysis shows no signature of residual aluminum oxide components making these films good candidates for a variety of applications at even shorter UV wavelengths.

  4. XPS analysis and luminescence properties of thin films deposited by the pulsed laser deposition technique

    NASA Astrophysics Data System (ADS)

    Dolo, J. J.; Swart, H. C.; Coetsee, E.; Terblans, J. J.; Ntwaeaborwa, O. M.; Dejene, B. F.

    2010-04-01

    This paper presents the effect of substrate temperature and oxygen partial pressure on the photoluminescence (PL) intensity of the Gd2O2S:Tb3 + thin films that were grown by using pulsed laser deposition (PLD). The PL intensity increased with an increase in the oxygen partial pressure and substrate temperature. The thin film deposited at an oxygen pressure of 900 mTorr and substrate temperature of 900°C was found to be the best in terms of the PL intensity of the Gd2O2S:Tb3 + emission. The main emission peak due to the 5D4-7F5 transition of Tb was measured at a wavelength of 545 nm. The stability of these thin films under prolonged electron bombardment was tested with a combination of techniques such as X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and Cathodoluminescence (CL) spectroscopy. It was shown that the main reason for the degradation in luminescence intensity under electron bombardment is the formation of a non-luminescent Gd2O3 layer, with small amounts of Gd2S3, on the surface.

  5. Deposition and characterization of molybdenum thin films using dc-plasma magnetron sputtering

    SciTech Connect

    Khan, Majid; Islam, Mohammad

    2013-12-15

    Molebdenum (Mo) thin films were deposited on well-cleaned soda-lime glass substrates using DC-plasma magnetron sputtering. In the design of experiment deposition was optimized for maximum beneficial characteristics by monitoring effect of process variables such as deposition power (100–200 W). Their electrical, structural and morphological properties were analyzed to study the effect of these variables. The electrical resistivity of Mo thin films could be reduced by increasing deposition power. Within the range of analyzed deposition power, Mo thin films showed a mono crystalline nature and the crystallites were found to have an orientation along [110] direction. The surface morphology of thin films showed that a highly dense micro structure has been obtained. The surface roughness of films increased with deposition power. The adhesion of Mo thin films could be improved by increasing the deposition power. Atomic force microscopy was used for the topographical study of the films and to determine the roughness of the films. X-ray diffractrometer and scanning electron microscopy analysis were used to investigate the crystallinity and surface morphology of the films. Hall effect measurement system was used to find resistivity, carrier mobility and carrier density of deposited films. The adhesion test was performed using scotch hatch tape adhesion test. Mo thin films prepared at deposition power of 200 W, substrate temperature of 23°C and Ar pressure of 0.0123 mbar exhibited a mono crystalline structure with an orientation along (110) direction, thickness of ∼550 nm and electrical resistivity value of 0.57 × 10{sup −4} Ω cm.

  6. Pulsed laser deposition of niobium nitride thin films

    NASA Astrophysics Data System (ADS)

    Farha, Ashraf Hassan; Ufuktepe, Yüksel; Myneni, Ganapati; Elsayed-Ali, Hani E.

    2015-12-01

    Niobium nitride (NbNx) films were grown on Nb and Si(100) substrates using pulsed laser deposition. NbNx films were deposited on Nb substrates using PLD with a Q-switched Nd:YAG laser (λ = 1064 nm, ˜40 ns pulse width, and 10 Hz repetition rate) at different laser fluences, nitrogen background pressures and deposition substrate temperatures. When all the fabrication parameters are fixed, except for the laser fluence, the surface roughness, nitrogen content, and grain size increase with increasing laser fluence. Increasing nitrogen background pressure leads to a change in the phase structure of the NbNx films from mixed β-Nb2N and cubic δ-NbN phases to single hexagonal β-Nb2N. The substrate temperature affects the preferred orientation of the crystal structure. The structural and electronic, properties of NbNx deposited on Si(100) were also investigated. The NbNx films exhibited a cubic δ-NbN with a strong (111) orientation. A correlation between surface morphology, electronic, and superconducting properties was found. The observations establish guidelines for adjusting the deposition parameters to achieve the desired NbNx film morphology and phase.

  7. Pulsed laser deposition of niobium nitride thin films

    SciTech Connect

    Farha, Ashraf Hassan Elsayed-Ali, Hani E.; Ufuktepe, Yüksel; Myneni, Ganapati

    2015-12-04

    Niobium nitride (NbN{sub x}) films were grown on Nb and Si(100) substrates using pulsed laser deposition. NbN{sub x} films were deposited on Nb substrates using PLD with a Q-switched Nd:YAG laser (λ = 1064 nm, ∼40 ns pulse width, and 10 Hz repetition rate) at different laser fluences, nitrogen background pressures and deposition substrate temperatures. When all the fabrication parameters are fixed, except for the laser fluence, the surface roughness, nitrogen content, and grain size increase with increasing laser fluence. Increasing nitrogen background pressure leads to a change in the phase structure of the NbN{sub x} films from mixed β-Nb{sub 2}N and cubic δ-NbN phases to single hexagonal β-Nb{sub 2}N. The substrate temperature affects the preferred orientation of the crystal structure. The structural and electronic, properties of NbN{sub x} deposited on Si(100) were also investigated. The NbN{sub x} films exhibited a cubic δ-NbN with a strong (111) orientation. A correlation between surface morphology, electronic, and superconducting properties was found. The observations establish guidelines for adjusting the deposition parameters to achieve the desired NbN{sub x} film morphology and phase.

  8. Ion beam analysis of copper selenide thin films prepared by chemical bath deposition

    NASA Astrophysics Data System (ADS)

    Andrade, E.; García, V. M.; Nair, P. K.; Nair, M. T. S.; Zavala, E. P.; Huerta, L.; Rocha, M. F.

    2000-03-01

    Analyses of Rutherford back scattered (RBS) 4He+-particle spectra of copper selenide thin films deposited on glass slides by chemical bath were carried out to determine the changes brought about in the thin film by annealing processes. The atomic density per unit area and composition of the films were obtained from these measurements. This analysis shows that annealing in a nitrogen atmosphere at 400°C leads to the conversion of Cu xSe thin film to Cu 2Se. Results of X-ray diffraction, optical, and electrical characteristics on the films are presented to supplement the RBS results.

  9. Third order nonlinearity in pulsed laser deposited LiNbO{sub 3} thin films

    SciTech Connect

    Tumuluri, Anil; Rapolu, Mounika; Rao, S. Venugopal E-mail: svrsp@uohyd.ernet.in; Raju, K. C. James E-mail: svrsp@uohyd.ernet.in

    2016-05-06

    Lithium niobate (LiNbO{sub 3}) thin films were prepared using pulsed laser deposition technique. Structural properties of the same were examined from XRD and optical band gap of the thin films were measured from transmittance spectra recorded using UV-Visible spectrophotometer. Nonlinear optical properties of the thin films were recorded using Z-Scan technique. The films were exhibiting third order nonlinearity and their corresponding two photon absorption, nonlinear refractive index, real and imaginary part of nonlinear susceptibility were calculated from open aperture and closed aperture transmission curves. From these studies, it suggests that these films have potential applications in nonlinear optical devices.

  10. Annealing effect on Cu2S thin films prepared by chemical bath deposition

    NASA Astrophysics Data System (ADS)

    More, Pawan; Dhanayat, Swapnali; Gattu, Ketan; Mahajan, Sandeep; Upadhye, Deepak; Sharma, Ramphal

    2016-05-01

    In present work Cu2S thin film fabricated on glass substrate by simple, cost effective chemical bath deposition method subsequently it annealed at 150°c.These films were studied for their structural, optical and electrical properties using X-ray diffraction, UV-vis spectrophotometer and I-V system. The results show successful synthesis of Cu2S thin films and improvement in crystalline nature of the thin film which resulted in reduced bad gap and resistance of the film. Thus these thinfilms prove to be a promising candidate for solar cell application.

  11. Titanium dioxide thin film deposited on flexible substrate by multi-jet electrospraying

    NASA Astrophysics Data System (ADS)

    Ni, Daihong; Yi, Wuming; Cao, Zhoubin; Gu, Wenhua

    2015-10-01

    Titanium dioxide thin film plays an important role in thin film solar cells, and has promising future in everyday applications including air cleaning and self-cleaning glass. With the concepts of flexible solar cells and wearable devices being more and more popular, there is increasing interest to coat titanium dioxide thin films on flexible substrates, such as aluminum foils. Many methods have been used to fabricate titanium dioxide thin films, such as dip-coating, spin coating, aerosol spray, plasma-assisted coating, electrospraying, and so on. Among them, electrospraying is especially suitable for thin film deposition on flexible substrates. This work reports fabrication of dense and uniform titanium dioxide thin films on glass as well as flexible aluminum foil using multi-jet electrospraying technique.

  12. AFM investigation and optical band gap study of chemically deposited PbS thin films

    NASA Astrophysics Data System (ADS)

    Zaman, S.; Mansoor, M.; Abubakar; Asim, M. M.

    2016-08-01

    The interest into deposition of nanocrystalline PbS thin films, the potential of designing and tailoring both the topographical features and the band gap energy (Eg) by controlling growth parameters, has significant technological importance. Nanocrystalline thin films of lead sulfide were grown onto glass substrates by chemical bath deposition (CBD) method. The experiments were carried out by varying deposition temperature. We report on the modification of structural and optical properties as a function of deposition temperature. The morphological changes of the films were analyzed by using SEM and AFM. AFM was also used to calculate average roughness of the films. XRD spectra indicated preferred growth of cubic phase of PbS films in (200) direction with increasing deposition time. Optical properties have been studied by UV-Spectrophotometer. From the diffused reflectance spectra we have calculated the optical Eg shift from 0.649-0.636 eV with increasing deposition time.

  13. Phase change properties of Ti-Sb-Te thin films deposited by thermal atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Song, Sannian; Shen, Lanlan; Song, Zhitang; Yao, Dongning; Guo, Tianqi; Li, Le; Liu, Bo; Wu, Liangcai; Cheng, Yan; Ding, Yuqiang; Feng, Songlin

    2016-10-01

    Phase change random access memory (PCM) appears to be the strongest candidate for next-generation high density nonvolatile memory. The fabrication of ultrahigh density PCM depends heavily on the thin film growth technique for the phase changing chalcogenide material. In this study, TiSb2Te4 (TST) thin films were deposited by thermal atomic layer deposition (ALD) method using TiCl4, SbCl3, (Et3Si)2Te as precursors. The threshold voltage for the cell based on thermal ALD-deposited TST is about 2.0 V, which is much lower than that (3.5 V) of the device based on PVD-deposited Ge2Sb2Te5 (GST) with the identical cell architecture. Tests of TST-based PCM cells have demonstrated a fast switching rate of 100 ns. Furthermore, because of the lower melting point and thermal conductivities of TST materials, TST-based PCM cells exhibit 19% reduction of pulse voltages for Reset operation compared with GST-based PCM cells. These results show that thermal ALD is an attractive method for the preparation of phase change materials.

  14. Matrix assisted pulsed laser deposition of melanin thin films

    NASA Astrophysics Data System (ADS)

    Bloisi, F.; Pezzella, A.; Barra, M.; Chiarella, F.; Cassinese, A.; Vicari, L.

    2011-07-01

    Melanins constitute a very important class of organic pigments, recently emerging as a potential material for a new generation of bioinspired biocompatible electrically active devices. In this paper, we report about the deposition of synthetic melanin films starting from aqueous suspensions by matrix assisted pulsed laser evaporation (MAPLE). In particular, we demonstrate that it is possible to deposit melanin films by MAPLE even if melanin (a) is not soluble in water and (b) absorbs light from UV to IR. AFM images reveal that the film surface features are highly depending on the deposition parameters. UV-VIS and FTIR spectra show both the optical properties and the molecular structure typical of melanins are preserved.

  15. Ultraviolet laser deposition of graphene thin films without catalytic layers

    NASA Astrophysics Data System (ADS)

    Sarath Kumar, S. R.; Alshareef, H. N.

    2013-01-01

    In this letter, the formation of nanostructured graphene by ultraviolet laser ablation of a highly ordered pyrolytic graphite target under optimized conditions is demonstrated, without a catalytic layer, and a model for the growth process is proposed. Previously, graphene film deposition by low-energy laser (2.3 eV) was explained by photo-thermal models, which implied that graphene films cannot be deposited by laser energies higher than the C-C bond energy in highly ordered pyrolytic graphite (3.7 eV). Here, we show that nanostructured graphene films can in fact be deposited using ultraviolet laser (5 eV) directly over different substrates, without a catalytic layer. The formation of graphene is explained by bond-breaking assisted by photoelectronic excitation leading to formation of carbon clusters at the target and annealing out of defects at the substrate.

  16. Pulsed Laser Deposition of Thin Film Material for Nonlinear Waveguides.

    DTIC Science & Technology

    1994-10-09

    addition, a method was devised to enhance the thickness uniformity or PLU-fabricated thin films, which is notoriously poor. This method uses a comic ...optic or novel design in order to produce concentric annular sources at the target being ablated. In principle, uniform coverage within rew percent is achievable for substrate sizes or a few inches, using current technology. (MM)

  17. ZnO Thin Films Deposited on Textile Material Substrates for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Duta, L.; Popescu, A. C.; Dorcioman, G.; Mihailescu, I. N.; Stan, G. E.; Zgura, I.; Enculescu, I.; Dumitrescu, I.

    We report on the coating with ZnO adherent thin films of cotton woven fabrics by Pulsed laser deposition technique in order to obtain innovative textile materials, presenting protective effects against UV radiations and antifungal action.

  18. Deposition of vanadium carbide thin films using compound target sputtering and their field emission

    SciTech Connect

    Liao, M.Y.; Gotoh, Y.; Tsuji, H.; Ishikawa, J.

    2005-09-15

    Vanadium carbide (VC) thin films were deposited on silicon substrates by direct sputtering of a VC target in an argon atmosphere. The structure, composition, and electrical properties of the films were investigated as functions of deposition conditions. The crystallographic structure of the film was strongly related to the argon pressure. VC films with (111) preferred orientation were formed at 2.0 Pa regardless of the substrate temperature examined, while amorphous films were obtained at the lowest pressure of 0.5 Pa. It was shown that carbon segregation within the film was difficult to avoid, but could be suppressed to some degree. To make a full understanding of the compositional variation in compound target sputtering process, deposition of chromium carbide thin films was also performed. Some common mechanisms involved in compound target sputtering process were discussed. Field emission measurements revealed that the VC film is a good electron emitter.

  19. Deposition of vanadium carbide thin films using compound target sputtering and their field emission

    NASA Astrophysics Data System (ADS)

    Liao, M. Y.; Gotoh, Y.; Tsuji, H.; Ishikawa, J.

    2005-09-01

    Vanadium carbide (VC) thin films were deposited on silicon substrates by direct sputtering of a VC target in an argon atmosphere. The structure, composition, and electrical properties of the films were investigated as functions of deposition conditions. The crystallographic structure of the film was strongly related to the argon pressure. VC films with (111) preferred orientation were formed at 2.0 Pa regardless of the substrate temperature examined, while amorphous films were obtained at the lowest pressure of 0.5 Pa. It was shown that carbon segregation within the film was difficult to avoid, but could be suppressed to some degree. To make a full understanding of the compositional variation in compound target sputtering process, deposition of chromium carbide thin films was also performed. Some common mechanisms involved in compound target sputtering process were discussed. Field emission measurements revealed that the VC film is a good electron emitter.

  20. Structural and Optical Study of Chemical Bath Deposited Nano-Structured CdS Thin Films

    NASA Astrophysics Data System (ADS)

    Kumar, Suresh; Sharma, Dheeraj; Sharma, Pankaj; Sharma, Vineet; Barman, P. B.; Katyal, S. C.

    2011-12-01

    CdS is commonly used as window layer in polycrystalline solar cells. The paper presents a structural and optical study of CdS nano-structured thin films. High quality CdS thin films are grown on commercial glass by means of chemical bath deposition. It involves an alkaline solution of cadmium salt, a complexant, a chalcogen source and a non-ionic surfactant. The films have been prepared under various process parameters. The chemically deposited films are annealed to estimate its effect on the structural and optical properties of films. These films (as -deposited and annealed) have been characterized by means of XRD, SEM and UV-Visible spectrophotometer. XRD of films show the nano-crystalline nature. The energy gap of films is found to be of direct in nature.

  1. Structural, morphological, optical and electrical properties of spray deposited lithium doped CdO thin films

    NASA Astrophysics Data System (ADS)

    Velusamy, P.; Babu, R. Ramesh; Ramamurthi, K.

    2016-05-01

    In the present work, CdO and Li doped CdO thin films were deposited on microscopic glass substrates at 300˚C by a spray pyrolysis experimental setup. The deposited CdO and Li doped CdO thin films were subjected to XRD, SEM, UV-VIS spectroscopy and Hall measurement analyses. XRD studies revealed the polycrystalline nature of the deposited films and confirmed that the deposited CdO and Li doped CdO thin films belong to cubic crystal system. The Scanning electron microscopy analysis revealed the information on shape of CdO and Li doped CdO films. Electrical study reveals the n-type semiconducting nature of CdO and the optical band gap is varied between 2.38 and 2.44 eV, depending on the Li doping concentrations.

  2. Structural, morphological, optical and electrical properties of spray deposited lithium doped CdO thin films

    SciTech Connect

    Velusamy, P.; Babu, R. Ramesh; Ramamurthi, K.

    2016-05-23

    In the present work, CdO and Li doped CdO thin films were deposited on microscopic glass substrates at 300°C by a spray pyrolysis experimental setup. The deposited CdO and Li doped CdO thin films were subjected to XRD, SEM, UV-VIS spectroscopy and Hall measurement analyses. XRD studies revealed the polycrystalline nature of the deposited films and confirmed that the deposited CdO and Li doped CdO thin films belong to cubic crystal system. The Scanning electron microscopy analysis revealed the information on shape of CdO and Li doped CdO films. Electrical study reveals the n-type semiconducting nature of CdO and the optical band gap is varied between 2.38 and 2.44 eV, depending on the Li doping concentrations.

  3. Epitaxial growth of magnetic ZnCuO thin films by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Kim, Dong Hun; Kim, Tae Cheol; Lee, Seung Han; Jung, Hyun Kyu; Jeong, Jaeeun; Han, Seung Ho

    2017-02-01

    The crystal structure and magnetic properties of epitaxial ZnO thin films doped with 5 at% Cu on SrTiO3 (001) and (111) substrates were investigated. In the case of films deposited in oxygen, unique crystallographic growth directions on different substrates were observed, while a metallic phase was detected in films grown under vacuum. The Cu-doped ZnO thin films deposited on the SrTiO3 (111) substrates, with hexagonal structures, showed a single epitaxial relationship with the substrates, whereas those deposited on the SrTiO3 (001) substrates showed a double epitaxial growth mode. The epitaxial ZnCuO thin films deposited on the SrTiO3 (111) substrates under high vacuum exhibited a ferromagnetic signal at room temperature.

  4. Process for thin film deposition of cadmium sulfide

    DOEpatents

    Muruska, H. Paul; Sansregret, Joseph L.; Young, Archie R.

    1982-01-01

    The present invention teaches a process for depositing layers of cadmium sulfide. The process includes depositing a layer of cadmium oxide by spray pyrolysis of a cadmium salt in an aqueous or organic solvent. The oxide film is then converted into cadmium sulfide by thermal ion exchange of the O.sup.-2 for S.sup.-2 by annealing the oxide layer in gaseous sulfur at elevated temperatures.

  5. Deposition And Characterization Of Ultra Thin Diamond Like Carbon Films

    NASA Astrophysics Data System (ADS)

    Tomcik, B.

    2010-07-01

    Amorphous hydrogenated and/or nitrogenated carbon films, a-C:H/a-C:N, in overall thickness up to 2 nm are materials of choice as a mechanical and corrosion protection layer of the magnetic media in modern hard disk drive disks. In order to obtain high density and void-free films the sputtering technology has been replaced by different plasma and ion beam deposition techniques. Hydrocarbon gas precursors, like C2H2 or CH4 with H2 and N2 as reactive gases are commonly used in Kaufman DC ion and RF plasma beam sources. Optimum incident energy of carbon ions, C+, is up to 100 eV while the typical ion current densities during the film formation are in the mA/cm2 range. Other carbon deposition techniques, like filtered cathodic arc, still suffer from co-deposition of fine nanosized carbon clusters (nano dust) and their improvements are moving toward arc excitation in the kHz and MHz frequency range. Non-destructive film analysis like μ-Raman optical spectroscopy, spectroscopic ellipsometry, FTIR and optical surface analysis are mainly used in the carbon film characterization. Due to extreme low film thicknesses the surface enhanced Raman spectroscopy (SERS) with pre-deposited layer of Au can reduce the signal collection time and minimize photon-induced damage during the spectra acquisition. Standard approach in the μ-Raman film evaluation is the measurement of the position (shift) and area of D and G-peaks under the deconvoluted overall carbon spectrum. Also, a slope of the carbon spectrum in the 1000-2000 cm-1 wavenumber range is used as a measure of the hydrogen intake within a film. Diamond like carbon (DLC) film should possess elasticity and self-healing properties during the occasional crash of the read-write head flying only couple of nanometers above the spinning film. Film corrosion protection capabilities are mostly evaluated by electrochemical tests, potentio-dynamic and linear polarization method and by business environmental method. Corrosion mechanism

  6. Laser deposition of SmCo thin film and coating on different substrates

    NASA Astrophysics Data System (ADS)

    Allocca, L.; Bonavolontà, C.; Giardini, A.; Lopizzo, T.; Morone, A.; Valentino, M.; Verrastro, M. F.; Viggiano, V.

    2008-10-01

    Thin films and coatings of permanent magnetic materials are very important for different electronic and micromechanical applications. This paper deals with the fabrication, using pulsed laser deposition (PLD) technique, of good quality magnetic SmCo thin films on polycarbonate, steel, silicon and amorphous quartz substrates, for low cost electronic applications like radio frequency identification (RFID) antennas and electromechanical devices for fuel feeding control in the automotive. X-ray fluorescence and magnetic scanning measurements using giant magneto-resistive (GMR) sensors have been performed to study the functional magnetic properties of the deposited thin films.

  7. Comparison of DC and RF magnetron sputtering systems for Electrochromic W/Ti Thin Film Deposition

    NASA Astrophysics Data System (ADS)

    Teke, Erdogan; Kiristi, Melek; Uygun Oksuz, Aysegul; Bozduman, Ferhat; Gulec, Ali; Oksuz, Lutfi; Hala, Ahmed M.

    2013-10-01

    In this study electrochromic tungsten-titanium thin films were deposited on ITO (indium thin oxide) glasses by using both DC and RF magnetron sputtering techniques. The discharges have been operated in same discharge power, geometry and argon/oxygen mixture pressure for comparison. The voltage and current characteristics and optical emission spectrums of both plasma systems will be given. The plasma parameters are determined by a double probe. ITO thin films coating electrical, optical and morphological characteristics will be compared.

  8. Formation of Tio2 Thin Film for Dye-Sensitized Solar Cell Application Using Electrophoresis Deposition

    NASA Astrophysics Data System (ADS)

    Nuryadi, Ratno; Akbar, Zico Alaia; Wargadipura, Agus Hadi S.; Gunlazuardi, Jarnuzi

    2010-10-01

    One of important processes on the fabrication of dye-sensitized solar cell (DSSC) is formation of TiO2 thin film. Thickness of TiO2 thin film is needed to be controlled in order to obtain optimum TiO2 thickness. Electrophoresis deposition is simple method for thin film deposition which enable us to control the thickness of thin film. In this work, the formation of TiO2 thin film on indium-doped tin oxide (ITO) glass using electrophoresis deposition is numerically and experimentally studied. We have succeeded to control the thickness of TiO2 thin film by changing of electrophoresis applied voltage and deposition time. In the experiment, TiO2 particles were suspended into isopropyl alcohol solution. Mg(NO3)2 was added to the solution in order to obtain the stable solution for electrophoresis. We found numerically that the Mg(NO3)2 in the range from 10-6 M to 10-4 M, is appropriate condition for the electrophoresis deposition. Using this method, we have fabricated DSSC device and study the effect of TiO2 thickness on DSSCs characteristic. Our results shows that the electrophoresis is not only essential for DSSC application but also for the other devices with a given thickness of TiO2 film.

  9. Electrochromic properties of molybdenum trioxide thin films prepared by chemical vapor deposition

    SciTech Connect

    Maruyama, Toshiro; Kanagawa, Tetsuya

    1995-05-01

    Electrochromic molybdenum trioxide thin films were prepared by chemical vapor deposition. The source material was molybdenum carbonyl. Amorphous molybdenum trioxide thin films were produced at a substrate temperature 300 C. Reduction and oxidation of the films in a 0.3M LiClO{sub 4} propylene carbonate solution caused desirable changes in optical absorption. Coulometry indicated that the coloration efficiency was 25.8 cm{sup 2}/C.

  10. Annealing dependence of residual stress and optical properties of TiO2 thin film deposited by different deposition methods.

    PubMed

    Chen, Hsi-Chao; Lee, Kuan-Shiang; Lee, Cheng-Chung

    2008-05-01

    Titanium oxide (TiO(2)) thin films were prepared by different deposition methods. The methods were E-gun evaporation with ion-assisted deposition (IAD), radio-frequency (RF) ion-beam sputtering, and direct current (DC) magnetron sputtering. Residual stress was released after annealing the films deposited by RF ion-beam or DC magnetron sputtering but not evaporation, and the extinction coefficient varied significantly. The surface roughness of the evaporated films exceeded that of both sputtered films. At the annealing temperature of 300 degrees C, anatase crystallization occurred in evaporated film but not in the RF ion-beam or DC magnetron-sputtered films. TiO(2) films deposited by sputtering were generally more stable during annealing than those deposited by evaporation.

  11. Thin films of SiO2 and hydroxyapatite on titanium deposited by spray pyrolysis.

    PubMed

    Jokanovic, V; Jokanovic, B; Izvonar, D; Dacic, B

    2008-05-01

    Wet spray pyrolysis of fine, well-dispersed a SiO2 sol was used for the deposition of thin films of silicon dioxide. The sol was obtained by hydrothermal precipitation of silicon acid from a solution at pH = 10. The morphology, roughness, phase composition, chemical homogeneity and the mechanism of the films were investigated by SEM, EDS and IR spectroscopy. The obtained results show a complete covering of the titanium substrate with SiO2 after 3 h of deposition. It was observed that the film thickness increased from 3 to 19 microm, the roughness of the film decreased from 12 to 3 microm, while the morphology of the deposit changed considerably. A hydroxyapatite film was prepared on the so-obtained SiO2 thin film by spray pyrolysis deposition and its morphology and phase composition were investigated.

  12. Effect of incident deposition angle on optical properties and surface roughness of TiO2 thin films

    NASA Astrophysics Data System (ADS)

    Pan, Yongqiang; Yang, Chen

    2016-10-01

    Optical properties, surface roughness and packing density of TiO2 thin films are studied by obliquely deposited on K9 glass by electron beam evaporation. The surface roughness of TiO2 thin films with different incident deposition angle is compared. The experimental results show that the transmittance increases and transmittance peak shifts to short wavelength with increasing incident deposition angle, the packing density of TiO2 thin films decrease from 0.80 to 0.34 with incident deposition angle increasing from 0° to 75°. The surface roughness of TiO2 thin films increase with increasing incident deposition angle. The surface roughness of TiO2 thin films is slightly bigger than the surface roughness of K9 substrate when the incident deposition angle is 75°. When the incident deposition angle is constant, TiO2 thin films surface roughness decrease with increase of film thickness.

  13. Plume behavior and thin film deposition by laser ablation using a hellicoidal shadow mask

    NASA Astrophysics Data System (ADS)

    Marcu, Aurelian; Grigoriu, Constantin; Jang, W.; Yatsui, Kiyoshi

    2000-02-01

    The laser ablation is one of the best ways to obtain smooth thin film deposited on various substrates. However, to obtain a 'droplets-free' surface some special experimental setups are necessary.ONe of them is the 'eclipse' method, using a plane shadow mask. Based on studies on the plume behavior in a 'standard' deposition and in a plane shadow mask eclipse deposition, we prose a new shadow mask having a an helicoidal shape, which permit to obtain a abetter film quality - maximum droplets size about 10 times smaller than for the plane shadow mask. The plume behavior and thin film quality are presented and discussed.

  14. Surface Acoustic Wave Monitor for Deposition and Analysis of Ultra-Thin Films

    NASA Technical Reports Server (NTRS)

    Hines, Jacqueline H. (Inventor)

    2015-01-01

    A surface acoustic wave (SAW) based thin film deposition monitor device and system for monitoring the deposition of ultra-thin films and nanomaterials and the analysis thereof is characterized by acoustic wave device embodiments that include differential delay line device designs, and which can optionally have integral reference devices fabricated on the same substrate as the sensing device, or on a separate device in thermal contact with the film monitoring/analysis device, in order to provide inherently temperature compensated measurements. These deposition monitor and analysis devices can include inherent temperature compensation, higher sensitivity to surface interactions than quartz crystal microbalance (QCM) devices, and the ability to operate at extreme temperatures.

  15. Electrophoretic deposition onto an insulator for thin film preparation toward electronic device fabrication

    NASA Astrophysics Data System (ADS)

    Miyajima, Shougo; Nagamatsu, Shuichi; Pandey, Shyam S.; Hayase, Shuzi; Kaneto, Keiichi; Takashima, Wataru

    2012-11-01

    An electrostatic film fabrication method utilizing the dielectric layer, entitled dielectric barrier electrophoretic deposition (DBEPD) has been proposed. We demonstrated the fabrication of uniform organic semiconductor thin film onto any kind of substrate by DBEPD. Optical absorption spectra of colloidal poly(3-hexylthiophene) (P3HT) film prepared by DBEPD exhibited the clear vibrational structure attributed to highly ordered domains. It was in contrast to the relatively disordered structure as shown in the case of P3HT film prepared by conventional electrophoretic deposition (EPD). Organic field effect transistors fabricated by each method showed similar organic field effect transistor characteristics, however, the uniformity of DBEPD film was superior to EPD film.

  16. Effect of deposition pressure on the structural and magnetic properties of cobalt ferrite thin films

    SciTech Connect

    Nongjai, R.; Khan, S.; Ahmad, H.; Khan, I.; Asokan, K.

    2013-06-03

    We present the influence of deposition pressure on the structural and magnetic properties of cobalt ferrite thin films. Thin films of Co ferrite were deposited by rf sputtering on Si (100) substrate and characterized by X - Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and Vibrating Sample Magnetometer (VSM). The XRD patterns showed the formation of crystalline single phase of the films. The particle size and surface roughness of the films were strongly influence by gas pressure. Hysteresis loops measured at room temperature showed the enhancement of magnetic properties with the increase of gas pressure which is attributed to the decrease of particle size.

  17. Study on mixed vanadium oxide thin film deposited by RF magnetron sputtering and its application

    NASA Astrophysics Data System (ADS)

    Ling, Zhang; Jianhui, Tu; Hao, Feng; Jingzhong, Cui

    Vanadium oxide (VOx) thin films were deposited on fused quartz using a pure metal vanadium target by RF reactive magnetron sputtering technique. Film microstructure, valence state, optical transmittance properties were studied. The mixed valence VOx thin films deposited with different thickness were found to be amorphous. And the optical transmittance curves are flatness in certain wavelength region. These films can be used to control the relative light intensity of the rubidium light beam between the rubidium lamp and the vapor cell, in order to optimize the working parameters of the rubidium frequency standard (RAFS).

  18. Pulsed laser deposition of semiconducting crystalline double-doped barium titanate thin films on nickel substrates

    NASA Astrophysics Data System (ADS)

    Apostol, I.; Stefan, N.; Luculescu, C. R.; Birjega, R.; Socol, M.; Miroiu, M.; Mihailescu, I. N.

    2011-02-01

    We synthesized by pulsed laser deposition (Ba,Sr,Y)TiO3 and (Ba,Pb,Y)TiO3 thin films on mechanically polished nickel substrates. The synthesized thin films were analyzed for: crystalline structure by X-ray diffractometry, morphology and surface topography by atomic force microscopy, optical and scanning electron microscopy, and elemental composition by energy dispersive X-ray spectroscopy and electrical properties by electrical measurements. We have shown that film properties were determined by the dopants, target composition, and deposition parameters (oxygen pressure, substrate temperature and incident laser fluence). All films exhibited a semiconducting behavior, as proved by the decrease of electrical resistance with heating temperature.

  19. Measurements of stress evolution during thin film deposition

    SciTech Connect

    Chason, E.; Floro, J.A.

    1996-05-01

    We have developed a technique for measuring thin film stress during growth by monitoring the wafer curvature. By measuring the deflection of multiple parallel laser beams with a CCD detector, the sensivity to vibration is reduced and a radius of curvature limit of 4 km has been obtained in situ. This technique also enables us to obtain a 2-dimensional profile of the surface curvature from the simultaneous reflection of a rectangular array of beams. Results from the growth of SiG alloy films are presented to demonstrate the unique information that can be obtained during growth.

  20. Chemical solution deposition of the highly c-axis oriented apatite type lanthanum silicate thin films.

    PubMed

    Hori, Shigeo; Takatani, Yasuhiro; Kadoura, Hiroaki; Uyama, Takeshi; Fujita, Satoru; Tani, Toshihiko

    2015-10-28

    Highly c-axis oriented apatite-type lanthanum silicate (LSO) thin films were fabricated by a simple solution coating method. In the solution coating method, LSO thin films are obtained by crystallization of initially deposited amorphous LSO precursor thin films. The degree of orientation was influenced by the precursor morphologies and a dense LSO precursor led to a high c-axis orientation perpendicular to the substrate. The oriented LSO thin films were composed of columnar grains with a single crystal orientation over the entire film thickness. In-plane orientation was not detected, which indicates that the c-axis orientation of the LSO thin films can be attributed to self-orientation.

  1. Morphological and crystalline characterization of pulsed laser deposited pentacene thin films for organic transistor applications

    NASA Astrophysics Data System (ADS)

    Pereira, Antonio; Bonhommeau, Sébastien; Sirotkin, Sergey; Desplanche, Sarah; Kaba, Mamadouba; Constantinescu, Catalin; Diallo, Abdou Karim; Talaga, David; Penuelas, Jose; Videlot-Ackermann, Christine; Alloncle, Anne-Patricia; Delaporte, Philippe; Rodriguez, Vincent

    2017-10-01

    We show that high-quality pentacene (P5) thin films of high crystallinity and low surface roughness can be produced by pulsed laser deposition (PLD) without inducing chemical degradation of the molecules. By using Raman spectroscopy and X-ray diffraction measurements, we also demonstrate that the deposition of P5 on Au layers result in highly disordered P5 thin films. While the P5 molecules arrange within the well-documented 1.54-nm thin-film phase on high-purity fused silica substrates, this ordering is indeed destroyed upon introducing an Au interlayer. This observation may be one explanation for the low electrical performances measured in P5-based organic thin film transistors (OTFTs) deposited by laser-induced forward transfer (LIFT).

  2. Antimony sulfide thin films prepared by laser assisted chemical bath deposition

    NASA Astrophysics Data System (ADS)

    Shaji, S.; Garcia, L. V.; Loredo, S. L.; Krishnan, B.; Aguilar Martinez, J. A.; Das Roy, T. K.; Avellaneda, D. A.

    2017-01-01

    Antimony sulfide (Sb2S3) thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in-situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb2S3 thin films produced by normal CBD and LACBD were analyzed by X-Ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb2S3 thin films for optoelectronic applications.

  3. Using fence post designs to speed the atomic layer deposition of optical thin films.

    PubMed

    Willey, Ronald R

    2008-05-01

    Atomic layer deposition (ALD) at this time is much slower than conventional optical thin-film deposition techniques. A more rapid ALD process for SiO(2) has been developed than for other ALD materials. A fence post design for optical thin films has thin layers of high-index posts standing above a broad low-index ground. If a design for ALD can be predominantly composed of SiO(2) layers with thin high-index layers, the deposition times can be correspondingly shortened, and it is shown that the required performance can still be nearly that of more conventional designs with high- and low-index layers of equal thickness. This combination makes the ALD benefits of conformal coating and precise thickness control more practical for optical thin-film applications.

  4. Plasma-enhanced chemical vapor deposition of low-resistive tungsten thin films

    SciTech Connect

    Kim, Y.T.; Min, S.; Hong, J.S. ); Kim, C.K. )

    1991-02-25

    Controlling the wafer temperatures from 200 to 500 {degree}C at H{sub 2}/WF{sub 6} flow ratio equal to 24, low-resistive (about 11 {mu}{Omega} cm) tungsten thin films are deposited by plasma-enhanced chemical vapor deposition. The as-deposited tungsten films have (110), (200), and (211) oriented bcc structures and Auger depth profile shows that fluorine and oxygen impurities are below the detection limit of Auger electron spectroscopy.

  5. Enhanced Bactericidal Activity of Silver Thin Films Deposited via Aerosol-Assisted Chemical Vapor Deposition.

    PubMed

    Ponja, Sapna D; Sehmi, Sandeep K; Allan, Elaine; MacRobert, Alexander J; Parkin, Ivan P; Carmalt, Claire J

    2015-12-30

    Silver thin films were deposited on SiO2-barrier-coated float glass, fluorine-doped tin oxide (FTO) glass, Activ glass, and TiO2-coated float glass via AACVD using silver nitrate at 350 °C. The films were annealed at 600 °C and analyzed by X-ray powder diffraction, X-ray photoelectron spectroscopy, UV/vis/near-IR spectroscopy, and scanning electron microscopy. All the films were crystalline, and the silver was present in its elemental form and of nanometer dimension. The antibacterial activity of these samples was tested against Escherichia coli and Staphylococcus aureus in the dark and under UV light (365 nm). All Ag-deposited films reduced the numbers of E. coli by 99.9% within 6 h and the numbers of S. aureus by 99.9% within only 2 h. FTO/Ag reduced bacterial numbers of E. coli to below the detection limit after 60 min and caused a 99.9% reduction of S. aureus within only 15 min of UV irradiation. Activ/Ag reduced the numbers of S. aureus by 66.6% after 60 min and TiO2/Ag killed 99.9% of S. aureus within 60 min of UV exposure. More remarkably, we observed a 99.9% reduction in the numbers of E. coli within 6 h and the numbers of S. aureus within 4 h in the dark using our novel TiO2/Ag system.

  6. Photoluminescence studies of chemically bath deposited nanocrystalline lead sulphide (PbS) thin films

    NASA Astrophysics Data System (ADS)

    Singh, L. Rajen; Singh, S. Bobby; London, R. K.; Sharma, H. B.; Rahman, A.

    2012-07-01

    Nanocrystalline lead sulphide (PbS) films have been deposited on glass substrates by chemical bath deposition (CBD) method. Lead acetate [Pb(CH3COOH)2] and thiourea [(NH2)2CS] were used as starting materials for deposition of PbS thin films. The as-deposited thin films were found to be crystalline having cubic phase structure with the strongest diffraction intensity along (200) plane. The grain sizes calculated from XRD spectra were found to decrease from 17 to 15 nm with the decrease in molar concentration of the precursor solutions. The structural, optical and photoluminescence properties of the PbS nanocrystalline thin film with different molar concentration were studied.

  7. Evaporation system and method for gas jet deposition of thin film materials

    DOEpatents

    Schmitt, Jerome J.; Halpern, Bret L.

    1994-01-01

    A method and apparatus for depositing thin films of materials such as metals, oxides and nitrides at low temperature relies on a supersonic free jet of inert carrier gas to transport vapor species generated from an evaporation source to the surface of a substrate. Film deposition vapors are generated from solid film precursor materials, including those in the form of wires or powders. The vapor from these sources is carried downstream in a low pressure supersonic jet of inert gas to the surface of a substrate where the vapors deposit to form a thin film. A reactant gas can be introduced into the gas jet to form a reaction product with the evaporated material. The substrate can be moved from the gas jet past a gas jet containing a reactant gas in which a discharge has been generated, the speed of movement being sufficient to form a thin film which is chemically composed of the evaporated material and reactant gases.

  8. Oxidative chemical vapor deposition of polyaniline thin films.

    PubMed

    Smolin, Yuriy Y; Soroush, Masoud; Lau, Kenneth K S

    2017-01-01

    Polyaniline (PANI) is synthesized via oxidative chemical vapor deposition (oCVD) using aniline as monomer and antimony pentachloride as oxidant. Microscopy and spectroscopy indicate that oCVD processing conditions influence the PANI film chemistry, oxidation, and doping level. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) indicate that a substrate temperature of 90 °C is needed to minimize the formation of oligomers during polymerization. Lower substrate temperatures, such as 25 °C, lead to a film that mostly includes oligomers. Increasing the oxidant flowrate to nearly match the monomer flowrate favors the deposition of PANI in the emeraldine state, and varying the oxidant flowrate can directly influence the oxidation state of PANI. Changing the reactor pressure from 700 to 35 mTorr does not have a significant effect on the deposited film chemistry, indicating that the oCVD PANI process is not concentration dependent. This work shows that oCVD can be used for depositing PANI and for effectively controlling the chemical state of PANI.

  9. Detection of copper ions from aqueous solutions using layered double hydroxides thin films deposited by PLD

    NASA Astrophysics Data System (ADS)

    Vlad, A.; Birjega, R.; Matei, A.; Luculescu, C.; Nedelcea, A.; Dinescu, M.; Zavoianu, R.; Pavel, O. D.

    2015-10-01

    Layered double hydroxides (LDHs) thin films with Mg-Al were deposited using pulsed laser deposition (PLD) technique. We studied the ability of our films to detect copper ions in aqueous solutions. Copper is known to be a common pollutant in water, originating from urban and industrial waste. Clay minerals, including layered double hydroxides (LDHs), can reduce the toxicity of such wastes by adsorbing copper. We report on the uptake of copper ions from aqueous solution on LDH thin films obtained via PLD. The obtained thin films were characterized using X-ray Diffraction, Atomic Force Microscopy, and Scanning Electron Microscopy with Energy Dispersive X-ray analysis. The results in this study indicate that LDHs thin films obtained by PLD have potential as an efficient adsorbent for removing copper from aqueous solution.

  10. Physical properties of chemically deposited Bi2S3 thin films using two post-deposition treatments

    NASA Astrophysics Data System (ADS)

    Moreno-García, H.; Messina, S.; Calixto-Rodriguez, M.; Martínez, H.

    2014-08-01

    As-deposited bismuth sulfide (Bi2S3) thin films prepared by chemical bath deposition technique were treated with thermal annealed in air atmosphere and argon AC plasma. The as-deposited, thermally annealing and plasma treatment Bi2S3 thin films have been characterized by X-ray diffraction (XRD) analysis, atomic force microscopy analysis (AFM), transmission, specular reflectance and electrical measurements. The structural, morphological, optical and electrical properties of the films are compared. The XRD analysis showed that both post-deposition treatments, transform the thin films from amorphous to a crystalline phase. The atomic force microscopy (AFM) measurement showed a reduction of roughness for the films treated in plasma. The energy band gap value of the as-prepared film was Eg = 1.61 eV, while for the film thermally annealed was Eg = 1.60 eV and Eg = 1.56 eV for film treated with Plasma. The electrical conductivity under illumination of the as-prepared films was 3.6 × 10-5 (Ω cm)-1, whereas the conductivity value for the thermally annealed films was 2.0 × 10-3 (Ω cm)-1 and for the plasma treated films the electrical conductivity increases up to 7.7 × 10-2 (Ω cm)-1.

  11. Influence of solvent on humidity sensing of sol-gel deposited ZnO thin films

    NASA Astrophysics Data System (ADS)

    Boukaous, Chahra; Telia, Azzedine; Horwat, David; Salah Aida, Mohammed; Boudine, Boubaker; Ghanem, Salah

    2014-02-01

    Undoped zinc oxide (ZnO) thin films have been grown on glass substrates by sol-gel process associated with dip coating. Two different solvents are used such as: 2-methoxyethanol and ethanol. The influence of these solvents on structural and optical properties of ZnO thin films has been investigated. Crystallinity and surface morphology of ZnO films are analyzed using X-ray diffractometry (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The optical properties are characterized by ultraviolet-visible (UV-vis) and photoluminescence spectroscopy (PL). Humidity sensors have been prepared with deposited ZnO films. Results reveal that ZnO thin film synthesized with 2-methoxyethanol showed a better crystalline quality and ultraviolet emission performance. In addition, a smaller transmittance in visible range and a higher surface roughness are observed. Sensing humidity test exhibits better sensitivity for sensor prepared with film deposited using 2-methoxyethanol as solvent.

  12. Copper selenide thin films by chemical bath deposition

    NASA Astrophysics Data System (ADS)

    García, V. M.; Nair, P. K.; Nair, M. T. S.

    1999-05-01

    We report the structural, optical, and electrical properties of thin films (0.05 to 0.25 μm) of copper selenide obtained from chemical baths using sodium selenosulfate or N,N-dimethylselenourea as a source of selenide ions. X-ray diffraction (XRD) studies on the films obtained from baths using sodium selenosulfate suggest a cubic structure as in berzelianite, Cu 2- xSe with x=0.15. Annealing the films at 400°C in nitrogen leads to a partial conversion of the film to Cu 2Se. In the case of films obtained from the baths containing dimethylselenourea, the XRD patterns match that of klockmannite, CuSe. Annealing these films in nitrogen at 400°C results in loss of selenium, and consequently a composition rich in copper, similar to Cu 2- xSe, is reached. Optical absorption in the films result from free carrier absorption in the near infrared region with absorption coefficient of ˜10 5 cm -1. Band-to-band transitions which gives rise to the optical absorption in the visible-ultraviolet region may be interpreted in terms of direct allowed transitions with band gap in the 2.1-2.3 eV range and indirect allowed transitions with band gap 1.2-1.4 eV. All the films, as prepared and annealed, show p-type conductivity, in the range of (1-5)×10 3 Ω -1 cm -1. This results in high near infrared reflectance, of 30-80%.

  13. Chemical vapor deposition of silicon, silicon dioxide, titanium and ferroelectric thin films

    NASA Astrophysics Data System (ADS)

    Chen, Feng

    Various silicon-based thin films (such as epitaxial, polycrystalline and amorphous silicon thin films, silicon dioxide thin films and silicon nitride thin films), titanium thin film and various ferroelectric thin films (such as BaTiO3 and PbTiO3 thin films) play critical roles in the manufacture of microelectronics circuits. For the past few years, there have been tremendous interests to search for cheap, safe and easy-to-use methods to develop those thin films with high quality and good step coverage. Silane is a critical chemical reagent widely used to deposit silicon-based thin films. Despite its wide use, silane is a dangerous material. It is pyrophoric, extremely flammable and may explode from heat, shock and/or friction. Because of the nature of silane, serious safety issues have been raised concerning the use, transportation, and storage of compressed gas cylinders of silane. Therefore it is desired to develop safer ways to deposit silicon-based films. In chapter III, I present the results of our research in the following fields: (1) Silane generator, (2) Substitutes of silane for deposition of silicon and silicon dioxide thin films, (3) Substitutes of silane for silicon dioxide thin film deposition. In chapter IV, hydropyridine is introduced as a new ligand for use in constructing precursors for chemical vapor deposition. Detachement of hydropyridine occurs by a low-temperature reaction leaving hydrogen in place of the hydropyridine ligands. Hydropyridine ligands can be attached to a variety of elements, including main group metals, such as aluminum and antimony, transition metals, such as titanium and tantalum, semiconductors such as silicon, and non-metals such as phosphorus and arsenic. In this study, hydropyridine-containing titanium compounds were synthesized and used as chemical vapor deposition precursors for deposition of titanium containing thin films. Some other titanium compounds were also studied for comparison. In chapter V, Chemical Vapor

  14. Deposition of hydroxyapatite thin films by Nd:YAG laser ablation: a microstructural study

    SciTech Connect

    Nistor, L.C.; Ghica, C.; Teodorescu, V.S.; Nistor, S.V. . E-mail: snistor@alpha1.infim.ro; Dinescu, M.; Matei, D.; Frangis, N.; Vouroutzis, N.; Liutas, C.

    2004-11-02

    Hydroxyapatite (HA) thin films has been successfully deposited by Nd:YAG laser ablation at {lambda} = 532 nm. The morphology and microstructure of the deposited layers was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution electron microscopy (HREM). Polycrystalline HA films were directly obtained with the substrate at 300 deg. C and without introducing water vapors in the deposition chamber. Electron paramagnetic resonance (EPR) measurements show that the oxygen stoichiometry in the HA films is also maintained. Depositions performed at {lambda} = 335 nm laser wavelength and 300 deg. C substrate temperature resulted in polycrystalline layers of mixed composition of HA and tricalciumphosphate (TCP)

  15. Annealing effect on structural and optical properties of chemical bath deposited MnS thin film

    NASA Astrophysics Data System (ADS)

    Ulutas, Cemal; Gumus, Cebrail

    2016-03-01

    MnS thin film was prepared by the chemical bath deposition (CBD) method on commercial microscope glass substrate deposited at 30 °C. The as-deposited film was given thermal annealing treatment in air atmosphere at various temperatures (150, 300 and 450 °C) for 1 h. The MnS thin film was characterized by using X-ray diffraction (XRD), UV-vis spectrophotometer and Hall effect measurement system. The effect of annealing temperature on the structural, electrical and optical properties such as optical constants of refractive index (n) and energy band gap (Eg) of the film was determined. XRD measurements reveal that the film is crystallized in the wurtzite phase and changed to tetragonal Mn3O4 phase after being annealed at 300 °C. The energy band gap of film decreased from 3.69 eV to 3.21 eV based on the annealing temperature.

  16. Bioinspired deposition of TiO2 thin films induced by hydrophobins.

    PubMed

    Santhiya, D; Burghard, Z; Greiner, C; Jeurgens, Lars P H; Subkowski, T; Bill, J

    2010-05-04

    The deposition of ceramic thin films from aqueous solutions at low temperature using biopolymers as templates has attracted much attention due to economic and environmental benefits. Titanium dioxide is one of the most attractive functional materials and shows a wide range of applications across vastly different areas because of its unique chemical, optical, and electrical properties. In the present work, we deposited smooth, nanocrystalline titania thin films by an aqueous deposition method on surface active and amphipathic proteins of fungal origin called hydrophobins. Initially, the hydrophobin molecules were self-assembled on a silicon substrate and characterized by angle-resolved X-ray photoelectron spectroscopy (AR-XPS), atomic force microscopy (AFM) and surface potential measurements. Thin films of titanium dioxide were deposited on the surface of hydrophobin self-assembled monolayers from aqueous titanium(IV) bis(ammonium lactate) dihydroxide solution at near-ambient conditions. The microstructure of the as-deposited films was analyzed by AFM, scanning and transmission electron microscopy, which revealed the presence of nanocrystals. The titania films were also characterized using AR-XPS and Fourier transform infrared spectroscopic (FTIR) techniques. Appropriate mechanisms involved in film deposition are suggested. Additionally, nanoindentation tests on as deposited titania films showed their high resistance against mechanical stress.

  17. Perpendicularly oriented barium ferrite thin films with low microwave loss, prepared by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Da-Ming, Chen; Yuan-Xun, Li; Li-Kun, Han; Chao, Long; Huai-Wu, Zhang

    2016-06-01

    Barium ferrite (BaM) thin films are deposited on platinum coated silicon wafers by pulsed laser deposition (PLD). The effects of deposition substrate temperature on the microstructure, magnetic and microwave properties of BaM thin films are investigated in detail. It is found that microstructure, magnetic and microwave properties of BaM thin film are very sensitive to deposition substrate temperature, and excellent BaM thin film is obtained when deposition temperature is 910 °C and oxygen pressure is 300 mTorr (1 Torr = 1.3332 × 102 Pa). X-ray diffraction patterns and atomic force microscopy images show that the best thin film has perpendicular orientation and hexagonal morphology, and the crystallographic alignment degree can be calculated to be 0.94. Hysteresis loops reveal that the squareness ratio (M r/M s) is as high as 0.93, the saturated magnetization is 4004 Gs (1 Gs = 104 T), and the anisotropy field is 16.5 kOe (1 Oe = 79.5775 A·m-1). Ferromagnetic resonance measurements reveal that the gyromagnetic ratio is 2.8 GHz/kOe, and the ferromagnetic resonance linewith is 108 Oe at 50 GHz, which means that this thin film has low microwave loss. These properties make the BaM thin films have potential applications in microwave devices. Project supported by the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices (Grant No. KFJJ201506), the Scientific Research Starting Foundation of Hainan University (Grant No. kyqd1539), and the Natural Science Foundation of Hainan Province (Grant No. 20165187).

  18. A simple chemical method for deposition of electrochromic Prussian blue thin films

    SciTech Connect

    Demiri, Sani; Najdoski, Metodija; Velevska, Julijana

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Prussian blue thin films were prepared by a simple chemical deposition method. Black-Right-Pointing-Pointer The films can be easily prepared from aqueous solution of Fe{sub 2}(SO{sub 4}){sub 3} and K{sub 4}[Fe(CN){sub 6}]. Black-Right-Pointing-Pointer The films show good electrochromic properties. Black-Right-Pointing-Pointer They change from deep blue color into green, and then back to blue and colorless. Black-Right-Pointing-Pointer The PB thin films exhibit stability and excellent reversibility. -- Abstract: This paper is about a recently developed new chemical method for deposition of Prussian blue thin films. The films are easily prepared by successive immersion of the substrates into an acidic aqueous solution of Fe{sub 2}(SO{sub 4}){sub 3} and K{sub 4}[Fe(CN){sub 6}]. It is calculated of the results from AFM analysis that the growth in the film thickness by one immersion cycle corresponds to an average increase of 6 nm. The characterization of the films with X-ray diffraction, SEM-EDS analysis and FTIR spectroscopy shows that the deposited material is amorphous hydrated Fe{sub 4}[Fe(CN){sub 6}]{sub 3}. The electrochromic properties are characterized by cyclic voltammetry and VIS spectrophotometry. The PB thin films exhibit stability and excellent reversibility, which make these films favorable for electrochromic devices.

  19. Laser deposition and direct-writing of thermoelectric misfit cobaltite thin films

    NASA Astrophysics Data System (ADS)

    Chen, Jikun; Palla-Papavlu, Alexandra; Li, Yulong; Chen, Lidong; Shi, Xun; Döbeli, Max; Stender, Dieter; Populoh, Sascha; Xie, Wenjie; Weidenkaff, Anke; Schneider, Christof W.; Wokaun, Alexander; Lippert, Thomas

    2014-06-01

    A two-step process combining pulsed laser deposition of calcium cobaltite thin films and a subsequent laser induced forward transfer as micro-pixel is demonstrated as a direct writing approach of micro-scale thin film structures for potential applications in thermoelectric micro-devices. To achieve the desired thermo-electric properties of the cobaltite thin film, the laser induced plasma properties have been characterized utilizing plasma mass spectrometry establishing a direct correlation to the corresponding film composition and structure. The introduction of a platinum sacrificial layer when growing the oxide thin film enables a damage-free laser transfer of calcium cobaltite thereby preserving the film composition and crystallinity as well as the shape integrity of the as-transferred pixels. The demonstrated direct writing approach simplifies the fabrication of micro-devices and provides a large degree of flexibility in designing and fabricating fully functional thermoelectric micro-devices.

  20. Ag Nanodots Emitters Embedded in a Nanocrystalline Thin Film Deposited on Crystalline Si Solar Cells.

    PubMed

    Park, Seungil; Ryu, Sel Gi; Ji, HyungYong; Kim, Myeong Jun; Peck, Jong Hyeon; Kim, Keunjoo

    2016-06-01

    We fabricated crystalline Si solar cells with the inclusion of various Ag nanodots into the additional emitters of nanocrystallite Si thin films. The fabricated process was carried out on the emitter surface of p-n junction for the textured p-type wafer. The Ag thin films were deposited on emitter surfaces and annealed at various temperatures. The amorphous Si layers were also deposited on the Ag annealed surfaces by hot-wire chemical vapor deposition and then the deposited layers were doped by the second n-type doping process to form an additional emitter. From the characterization, both the Ag nanodots and the deposited amorphous Si thin films strongly reduce photo-reflectances in a spectral region between 200-400 nm. After embedding Ag nanodots in nanocrystallite Si thin films, a conversion efficiency of the sample with added emitter was achieved to 15.1%, which is higher than the 14.1% of the reference sample and the 14.7% of the de-posited sample with a-Si:H thin film after the Ag annealing process. The additional nanocrystallite emitter on crystalline Si with Ag nanodots enhances cell properties.

  1. Deposition of ScAIN thin film using RF-sputtering method

    NASA Astrophysics Data System (ADS)

    Fujii, Satoshi; Kadena, Hayate; Hashimoto, Ken-ya

    2017-07-01

    High-Sc-content ScAlN thin films have attracted significant attention because of their strong piezoelectric properties. Akiyama et al. found that the piezoelectricity of ScAlN thin films increased monotonically with increasing Sc concentration, r. The piezoelectricity reached a maximum at r = 43 at%, at which the piezoelectric coefficient, d33, was five times that of pure AlN. The Akiyama group showed that the d33 of a ScAlN thin film with a high Sc content and wurtzite structure would be much larger than that of the 43 at% Sc film, as calculated by first-principles methods. However, ScAlN thin films typically exhibit a rock-salt rather than a wurtzite structure with increasing Sc content, because ScN has a rock-salt structure at thermal equilibrium. In this report, we studied the deposition of ScAlN thin films using a RF-sputtering method, and it's characterization to clarify the deposition conditions needed for films with high piezoelectricity. The result of micro-Raman spectroscopy measurement shows that, as the Sc content of the ScAlN thin film increases, the peak at ˜800 nm-1 of the A1 mode, due to Sc atoms in the Al sites of the wurtzite structure, shifts to lower frequency for these sputtering conditions. This means that Sc atoms occupy Al sites in the wurtzite structure in the thin film until the Sc content reaches 33%. This phenomenon was also observed for AlGaN thin films. The peak near 700 cm-1 for the ScN thin film, ascribed to a cubic structure, is deformed with increasing Al content.

  2. Gas sensing studies of pulsed laser deposition deposited WO3 nanorod based thin films.

    PubMed

    Ahmad, Muhammad Z; Kang, Joonhee; Zoolfakar, Ahmad S; Sadek, Abu Z; Wlodarski, Wojtek

    2013-12-01

    WO3 nanorod based thin films were deposited via pulsed laser deposition onto quartz conductometric transducers with pre-patterned gold interdigitated transducers (IDT) employing the shortest wavelength (193 nm) ArF excimer laser. Micro-characterization techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to study surface morphology and crystal structure. It was observed that the fabricated films showed nanocolumnar features perpendicular to the surface. The measured sizes of the nanorods were found to be approximately -50 nm in diameter. The high resolution TEM (HRTEM) image of the nanorods based WO3 showed the WO3 lattice spacing of 3.79 angstroms corresponding to the (020) plane of monoclinic WO3. Gas sensing characterizations of the developed sensors were tested towards hydrogen and ethanol at temperatures between room and 400 degrees C. The sensor exhibited high response towards H2 and ethanol at operating temperatures of 170 and 400 degrees C, respectively. The excellent sensing characteristics of WO3 films towards ethanol and H2 at low concentrations offer great potential for low cost and stable gas sensing.

  3. Structural and optical properties of manganese oxide thin films deposited by pulsed laser deposition at different substrate temperatures

    NASA Astrophysics Data System (ADS)

    Jamil, H.; Khaleeq-ur-Rahman, M.; Dildar, I. M.; Shaukat, Saima

    2017-09-01

    We report the use of pulsed laser deposition (PLD) to grow manganese oxide thin films at a fixed low oxygen pressure at different temperatures on silicon (1 0 0) substrates. Structural properties of the thin films were examined using x-ray diffraction and Fourier transform infrared spectroscopy. Surface morphology and topography of the films was determined using atomic force microscopy and optical microscopy, while optical properties of the thin films were studied using spectroscopic ellipsometry. It was found that PLD is a convenient technique to deposit different phases of manganese oxide by tuning the deposition temperature. All measured physical properties such as morphology, topography, crystallite size, and optical band gap were clearly dependent on the substrate temperature chosen.

  4. Using different chemical methods for deposition of copper selenide thin films and comparison of their characterization.

    PubMed

    Güzeldir, Betül; Sağlam, Mustafa

    2015-11-05

    Different chemical methods such as Successive Ionic Layer Adsorption and Reaction (SILAR), spin coating and spray pyrolysis methods were used to deposite of copper selenide thin films on the glass substrates. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray analysis (EDX) spectroscopy and UV-vis spectrophotometry. The XRD and SEM studies showed that all the films exhibit polycrystalline nature and crystallinity of copper selenide thin films prepared with spray pyrolysis greater than spin coating and SILAR methods. From SEM and AFM images, it was observed copper selenide films were uniform on the glass substrates without any visible cracks or pores. The EDX spectra showed that the expected elements exist in the thin films. Optical absorption studies showed that the band gaps of copper selenide thin films were in the range 2.84-2.93 eV depending on different chemical methods. The refractive index (n), optical static and high frequency dielectric constants (ε0, ε∞) values were calculated by using the energy bandgap values for each deposition method. The obtained results from different chemical methods revealed that the spray pyrolysis technique is the best chemical deposition method to fabricate copper selenide thin films. This absolute advantage was lead to play key roles on performance and efficiency electrochromic and photovoltaic devices. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. As2Se3 thin films deposited by frequency assisted thermal evaporation – morphology and structure

    NASA Astrophysics Data System (ADS)

    Hristova-Vasileva, T.; Bineva, I.; Dinescu, A.; Danila, M.; Arsova, D.

    2017-01-01

    Thin As2Se3 films with thicknesses of 60 and 250 nm were deposited from the initial compound by frequency assisted thermal evaporation in vacuum – a new approach for shaping thin films surface. Frequencies of 0, 50 and 4000 Hz were applied on the substrates during the deposition process. The morphology was evaluated using AFM and SEM techniques. Some main optical properties and specifics of the films were determined by the means of spectroscopic ellipsometry analysis. The structure of the samples was investigated by XRD. A possible mechanism for explanation of the observed peculiarities is proposed on the basis of the classical materials science and molecular thermodynamics.

  6. Characterization of lead zirconate titanate--lanthanum ruthenate thin film structures prepared by chemical solution deposition.

    PubMed

    Bencan, Andreja; Malic, Barbara; Drazic, Goran; Vukadinović, Miso; Kosec, Marija

    2007-01-01

    In this work, the results of compositional and microstructural analysis of lead zirconate titanate--lanthanum ruthenate thin film structures prepared by chemical solution deposition are discussed. The cross-section transmission electron microscope (TEM) micrographs of the La-Ru-O film deposited on a SiO2/Si substrate and annealed at 700 degrees C revealed RuO2 crystals embedded in a glassy silicate matrix. When the La-Ru-O film was deposited on a Pt/TiO2/SiO2/Si substrate, RuO2 and La4Ru6O19 crystallized after annealing at 700 degrees C. After firing at 550 degrees C randomly oriented lead zirconate titanate (PZT) thin films crystallized on the La-Ru-O/SiO2/Si substrate, while on La-Ru-O/Pt/TiO2/SiO2/Si substrates PZT thin films with (111) preferred orientation were obtained. No diffusion of the Ru atoms in the PZT film was found. Ferroelectric response of PZT thin films on these substrates is shown in comparison with the PZT film deposited directly on the Pt/TiO2/SiO2/Si substrate without a La-Ru-O layer.

  7. Development of plasma assisted thermal vapor deposition technique for high-quality thin film

    NASA Astrophysics Data System (ADS)

    Lee, Kang-Il; Choi, Yong Sup; Park, Hyun Jae

    2016-12-01

    The novel technique of Plasma-Assisted Vapor Deposition (PAVD) is developed as a new deposition method for thin metal films. The PAVD technique yields a high-quality thin film without any heating of the substrate because evaporated particles acquire energy from plasma that is confined to the inside of the evaporation source. Experiments of silver thin film deposition have been carried out in conditions of pressure lower than 10-3 Pa. Pure silver plasma generation is verified by the measurement of the Ag-I peak using optical emission spectroscopy. A four point probe and a UV-VIS spectrophotometer are used to measure the electrical and optical properties of the silver film that is deposited by PAVD. For an ultra-thin silver film with a thickness of 6.5 nm, we obtain the result of high-performance silver film properties, including a sheet resistance <20 Ω sq-1 and a visible-range transmittance >75%. The PAVD-film properties show a low sheet resistance of 30% and the same transmittance with conventional thermal evaporation film. In the PAVD source, highly energetic particles and UV from plasma do not reach the substrate because the plasma is completely shielded by the optimized nozzle of the crucible. This new PAVD technique could be a realistic solution to improve the qualities of transparent electrodes for organic light emission device fabrication without causing damage to the organic layers.

  8. Development of plasma assisted thermal vapor deposition technique for high-quality thin film.

    PubMed

    Lee, Kang-Il; Choi, Yong Sup; Park, Hyun Jae

    2016-12-01

    The novel technique of Plasma-Assisted Vapor Deposition (PAVD) is developed as a new deposition method for thin metal films. The PAVD technique yields a high-quality thin film without any heating of the substrate because evaporated particles acquire energy from plasma that is confined to the inside of the evaporation source. Experiments of silver thin film deposition have been carried out in conditions of pressure lower than 10(-3) Pa. Pure silver plasma generation is verified by the measurement of the Ag-I peak using optical emission spectroscopy. A four point probe and a UV-VIS spectrophotometer are used to measure the electrical and optical properties of the silver film that is deposited by PAVD. For an ultra-thin silver film with a thickness of 6.5 nm, we obtain the result of high-performance silver film properties, including a sheet resistance <20 Ω sq(-1) and a visible-range transmittance >75%. The PAVD-film properties show a low sheet resistance of 30% and the same transmittance with conventional thermal evaporation film. In the PAVD source, highly energetic particles and UV from plasma do not reach the substrate because the plasma is completely shielded by the optimized nozzle of the crucible. This new PAVD technique could be a realistic solution to improve the qualities of transparent electrodes for organic light emission device fabrication without causing damage to the organic layers.

  9. Deposition of thin mesoporous silica films on glass substrates from basic solution.

    PubMed

    Shimura, Naoki; Ogawa, Makoto

    2006-11-01

    Transparent thin (ca. 100 nm) films of silica-surfactant mesostructured materials were deposited on borosilicate glass plates and soda-lime glass tubes from aqueous solutions containing tetraethoxysilane, alkyltrimethylammonium chloride, ammonia, and methanol. By calcination in air, the films became mesoporous (BET surface area of 700-900 m2 g-1) with pore diameter 2.0-2.8 nm.

  10. Properties of RF sputtered cadmium telluride (CdTe) thin films: Influence of deposition pressure

    SciTech Connect

    Kulkarni, R. R.; Pawbake, A. S.; Waykar, R. G.; Rondiya, S. R.; Jadhavar, A. A.; Pandharkar, S. M.; Karpe, S. D.; Diwate, K. D.; Jadkar, S. R.

    2016-04-13

    Influence of deposition pressure on structural, morphology, electrical and optical properties of CdTe thin films deposited at low substrate temperature (100°C) by RF magnetron sputtering was investigated. The formation of CdTe was confirmed by low angle XRD and Raman spectroscopy. The low angle XRD analysis revealed that the CdTe films have zinc blende (cubic) structure with crystallites having preferred orientation in (111) direction. Raman spectra show the longitudinal optical (LO) phonon mode peak ∼ 165.4 cm{sup -1} suggesting high quality CdTe film were obtained over the entire range of deposition pressure studied. Scanning electron microscopy analysis showed that films are smooth, homogenous, and crack-free with no evidence of voids. The EDAX data revealed that CdTe films deposited at low deposition pressure are high-quality stoichiometric. However, for all deposition pressures, films are rich in Cd relative to Te. The UV-Visible spectroscopy analysis show the blue shift in absorption edge with increasing the deposition pressure while the band gap show decreasing trend. The highest electrical conductivity was obtained for the film deposited at deposition pressure 1 Pa which indicates that the optimized deposition pressure for our sputtering unit is 1 Pa. Based on the experimental results, these CdTe films can be useful for the application in the flexible solar cells and other opto-electronic devices.

  11. Properties of RF sputtered cadmium telluride (CdTe) thin films: Influence of deposition pressure

    NASA Astrophysics Data System (ADS)

    Kulkarni, R. R.; Pawbake, A. S.; Waykar, R. G.; Rondiya, S. R.; Jadhavar, A. A.; Pandharkar, S. M.; Karpe, S. D.; Diwate, K. D.; Jadkar, S. R.

    2016-04-01

    Influence of deposition pressure on structural, morphology, electrical and optical properties of CdTe thin films deposited at low substrate temperature (100°C) by RF magnetron sputtering was investigated. The formation of CdTe was confirmed by low angle XRD and Raman spectroscopy. The low angle XRD analysis revealed that the CdTe films have zinc blende (cubic) structure with crystallites having preferred orientation in (111) direction. Raman spectra show the longitudinal optical (LO) phonon mode peak ˜ 165.4 cm-1 suggesting high quality CdTe film were obtained over the entire range of deposition pressure studied. Scanning electron microscopy analysis showed that films are smooth, homogenous, and crack-free with no evidence of voids. The EDAX data revealed that CdTe films deposited at low deposition pressure are high-quality stoichiometric. However, for all deposition pressures, films are rich in Cd relative to Te. The UV-Visible spectroscopy analysis show the blue shift in absorption edge with increasing the deposition pressure while the band gap show decreasing trend. The highest electrical conductivity was obtained for the film deposited at deposition pressure 1 Pa which indicates that the optimized deposition pressure for our sputtering unit is 1 Pa. Based on the experimental results, these CdTe films can be useful for the application in the flexible solar cells and other opto-electronic devices.

  12. Pulsed laser deposition of AlMgB14 thin films

    SciTech Connect

    Britson, Jason Curtis

    2008-11-18

    Hard, wear-resistant coatings of thin film borides based on AlMgB14 have the potential to be applied industrially to improve the tool life of cutting tools and pump vanes and may account for several million dollars in savings as a result of reduced wear on these parts. Past work with this material has shown that it can have a hardness of up to 45GPa and be fabricated into thin films with a similar hardness using pulsed laser deposition. These films have already been shown to be promising for industrial applications. Cutting tools coated with AlMgB14 used to mill titanium alloys have been shown to substantially reduce the wear on the cutting tool and extend its cutting life. However, little research into the thin film fabrication process using pulsed laser deposition to make AlMgB14 has been conducted. In this work, research was conducted into methods to optimize the deposition parameters for the AlMgB14 films. Processing methods to eliminate large particles on the surface of the AlMgB14 films, produce films that were at least 1m thick, reduce the surface roughness of the films, and improve the adhesion of the thin films were investigated. Use of a femtosecond laser source rather than a nanosecond laser source was found to be effective in eliminating large particles considered detrimental to wear reduction properties from the films. Films produced with the femtosecond laser were also found to be deposited at a rate 100 times faster than those produced with the nanosecond laser. However, films produced with the femtosecond laser developed a relatively high RMS surface roughness around 55nm. Attempts to decrease the surface roughness were largely unsuccessful. Neither increasing the surface temperature of the substrate during deposition nor using a double pulse to ablate the material was found to be extremely successful to reduce the surface roughness. Finally, the adhesion of the thin films to M2 tool steel

  13. Chemical Vapor Deposition for Ultra-lightweight Thin-film Solar Arrays for Space

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Raffaelle, Ryne P.; Banger, Kulbinder K.; Jin, Michael H.; Lau, Janice E.; Harris, Jerry D.; Cowen, Jonathan E.; Duraj, Stan A.

    2002-01-01

    The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power, (W/kg). The use of a polycrystalline chalcopyrite absorber layer for thin film solar cells is considered as the next generation photovoltaic devices. A key technical issues outlined in the 2001 U.S. Photovoltaic Roadmap, is the need to develop low cost, high throughput manufacturing for high-efficiency thin film solar cells. At NASA GRC we have focused on the development of new single-source-precursors (SSPs) and their utility to deposit the chalcopyrite semi-conducting layer (CIS) onto flexible substrates for solar cell fabrication. The syntheses and thermal modulation of SSPs via molecular engineering is described. Thin-film fabrication studies demonstrate the SSPs can be used in a spray CVD process, for depositing CIS at reduced temperatures, which display good electrical properties, suitable for PV devices.

  14. Pyrolyzed thin film carbon

    NASA Technical Reports Server (NTRS)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  15. Impact of deposition-rate fluctuations on thin-film thickness and uniformity

    DOE PAGES

    Oliver, Joli B.

    2016-11-04

    Variations in deposition rate are superimposed on a thin-film–deposition model with planetary rotation to determine the impact on film thickness. Variations in magnitude and frequency of the fluctuations relative to the speed of planetary revolution lead to thickness errors and uniformity variations up to 3%. Sufficiently rapid oscillations in the deposition rate have a negligible impact, while slow oscillations are found to be problematic, leading to changes in the nominal film thickness. Finally, superimposing noise as random fluctuations in the deposition rate has a negligible impact, confirming the importance of any underlying harmonic oscillations in deposition rate or source operation.

  16. Impact of deposition-rate fluctuations on thin-film thickness and uniformity

    SciTech Connect

    Oliver, Joli B.

    2016-11-04

    Variations in deposition rate are superimposed on a thin-film–deposition model with planetary rotation to determine the impact on film thickness. Variations in magnitude and frequency of the fluctuations relative to the speed of planetary revolution lead to thickness errors and uniformity variations up to 3%. Sufficiently rapid oscillations in the deposition rate have a negligible impact, while slow oscillations are found to be problematic, leading to changes in the nominal film thickness. Finally, superimposing noise as random fluctuations in the deposition rate has a negligible impact, confirming the importance of any underlying harmonic oscillations in deposition rate or source operation.

  17. Deposition of ZnTe thin films by close spaced sublimation: Structural and electrical studies

    SciTech Connect

    Goyal, D.J.; Bilurkar, P.G.; Thorat, S.K.; Mate, N.V.

    1998-12-31

    Zinc telluride has the potential of being a low-cost, environmentally stable, low-resistance and easily manufacturable back contact for CdS/CdTe solar cells. Close Spaced Sublimation (CSS) technique is used to deposit thin films of ZnTe. The results are reported in this study. The effects of substrate temperature and film thickness on the structural properties of the deposited thin films are studied. X-ray diffractograms show that all the films prominently exhibit presence of (111) and (200) orientations. However, the degree of the preferred orientation changes as a function of the film thickness. Increase in film thickness reduces the preferential orientation. The as deposited ZnTe thin films, being that of p-type semiconductor, are highly resistive. In order to effectively use these as contact to CdS/CdTe solar cells, they are made more conductive by doping copper. The doping is effected by dipping the films in alcoholic solution of copper chloride, followed by air annealing at 200 C. The resistivity of all the doped films drops drastically in the initial 10 minutes of annealing. The extent of doping is controlled by varying the dipping time. The effects of substrate temperature, film thickness and doping, on the stoichiometry of the films, are studied using Atomic Absorption Spectroscopy (AAS).

  18. Laser-induced chemical vapour deposition of conductive and insulating thin films

    NASA Astrophysics Data System (ADS)

    Reisse, G.; Gaensicke, F.; Ebert, R.; Illmann, U.; Johansen, H.

    1992-01-01

    Investigations concerning the laser-induced chemical vapour deposition of Mo, W, Co and TiSi 2 conductive thin film structures from Mo(CO) 6, W(CO) 6, Co 2(CO) 8, TiCl 4 and SiH 4 using a direct writing method are presented. SiO 2 thin films were deposited from SiH 4 and N 2O in a large area deposition process stimulated by an excimer laser by using a parallel beam configuration.

  19. Stabilizing laser energy density on a target during pulsed laser deposition of thin films

    DOEpatents

    Dowden, Paul C.; Jia, Quanxi

    2016-05-31

    A process for stabilizing laser energy density on a target surface during pulsed laser deposition of thin films controls the focused laser spot on the target. The process involves imaging an image-aperture positioned in the beamline. This eliminates changes in the beam dimensions of the laser. A continuously variable attenuator located in between the output of the laser and the imaged image-aperture adjusts the energy to a desired level by running the laser in a "constant voltage" mode. The process provides reproducibility and controllability for deposition of electronic thin films by pulsed laser deposition.

  20. Nanomechanical properties of platinum thin films synthesized by atomic layer deposition

    SciTech Connect

    Mamun, M.A.; Gu, D.; Baumgart, H.; Elmustafa, A.A.

    2015-03-01

    The nanomechanical properties of Pt thin films grown on Si (100) using atomic layer deposition (ALD) were investigated using nanoindentation. Recently, atomic layer deposition (ALD) has successfully demonstrated the capability to deposit ultra-thin films of platinum (Pt). Using (methylcyclopentadienyl) trimethylplatinum (MeCpPtMe3) as chemical platinum precursor and oxygen (O2) as the oxidizing agent, the ALD synthesis of Pt can be achieved with high conformity and excellent film uniformity. The ALD process window for Pt films was experimentally established in the temperature range between 270 °C and 320 °C, where the sheet conductance was constant over that temperature range, indicating stable ALD Pt film growth rate. ALD growth of Pt films exhibits very poor nucleation and adhesion characteristics on bare Si surfaces when the native oxide was removed by 2% HF etch. Pt adhesion improves for thermally oxidized Si wafers and for Si wafers covered with native oxide. Three ALD Pt films deposited at 800, 900, and 1000 ALD deposition cycles were tested for the structural and mechanical properties. Additionally, the sample with 900 ALD deposition cycles was further annealed in forming gas (95% N2 and 5% H2) at 450 °C for 30 min in order to passivate dangling bonds in the grain boundaries of the polycrystalline Pt film. Cross-sectional transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic force microscopy (AFM), and scanning electron microscope (SEM) were employed to characterize the films' surface structure and morphology. Nanoindentation technique was used to evaluate the hardness and modulus of the ALD Pt films of various film thicknesses. The results indicate that the films depict comparable hardness and modulus results; however, the 800 and 1000 ALD deposition cycles films without forming gas annealing experienced significant amount of pileup, whereas the 900 ALD deposition cycles sample annealed in forming gas resulted in a smaller pileup.

  1. Electrochromic Property of MoO3 Thin Films Deposited by Chemical Vapor Transport Synthesis

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Gun; Kim, Se Hoon; Do Kim, Young

    2011-10-01

    The transmittance of electrochromic MoO3 thin films by chemical vapor transport (CVT) deposition and post-annealing on indium tin oxide (ITO) glass reached 80% with low reflectivity. Optical analysis demonstrated a 3.60 eV band gap energy in MoO3 thin film. Transmittance changes of 50% between coloration and decoloration (˜30 and ˜80%) at 533 nm under the bias change frequency revealed reversible electrochromic properties and stability. A coloration efficiency of the annealed MoO3 thin film was 23.7 cm2/C. Coloration responsibility was predominant with reliable performances by bias change.

  2. InGaZnO semiconductor thin film fabricated using pulsed laser deposition.

    PubMed

    Chen, Jiangbo; Wang, Li; Su, Xueqiong; Kong, Le; Liu, Guoqing; Zhang, Xinping

    2010-01-18

    The InGaZnO thin films are fabricated on the quartz glass using pulsed laser deposition (PLD), where the target is prepared by mixing the Ga(2)O(3), In(2)O(3), and ZnO powders at a mol ratio of 1:1:8 before the solid-state reactions in a tube furnace at the atmospheric pressure. The product thin films were characterized comprehensively by X-ray diffraction, atomic force microscopy, Hall-effect investigation, and X-ray photoelectron spectroscopy. Thus, we demonstrate semiconductor thin-film materials with high smoothness, high transmittance in visible region, and excellent electrical properties.

  3. Ion beam assisted deposition of a thin film coating on a gradient-index lens array.

    PubMed

    Kyogoku, T; Suzuki, T; Mino, M

    1990-10-01

    A new coating method which employs ion bombardment has been developed for a gradient-index (GRIN) rod lens array using silicone rubber and fiber reinforced plastic plates in its construction. The thin film coatings deposited using this method passed the durability tests on the basis of MIL-M-13508C. The adhesion of the thin film coating was strong and durable enough to allow for use on GRIN rod lens arrays in photocopiers. The effect of ion bombardment has been investigated with thin film analysis data by Fourier transform infrared microspectroscopy and secondary ion mass spectrometry.

  4. Biocompatibility and Surface Properties of TiO2 Thin Films Deposited by DC Magnetron Sputtering

    PubMed Central

    López-Huerta, Francisco; Cervantes, Blanca; González, Octavio; Hernández-Torres, Julián; García-González, Leandro; Vega, Rosario; Herrera-May, Agustín L.; Soto, Enrique

    2014-01-01

    We present the study of the biocompatibility and surface properties of titanium dioxide (TiO2) thin films deposited by direct current magnetron sputtering. These films are deposited on a quartz substrate at room temperature and annealed with different temperatures (100, 300, 500, 800 and 1100 °C). The biocompatibility of the TiO2 thin films is analyzed using primary cultures of dorsal root ganglion (DRG) of Wistar rats, whose neurons are incubated on the TiO2 thin films and on a control substrate during 18 to 24 h. These neurons are activated by electrical stimuli and its ionic currents and action potential activity recorded. Through X-ray diffraction (XRD), the surface of TiO2 thin films showed a good quality, homogeneity and roughness. The XRD results showed the anatase to rutile phase transition in TiO2 thin films at temperatures between 500 and 1100 °C. This phase had a grain size from 15 to 38 nm, which allowed a suitable structural and crystal phase stability of the TiO2 thin films for low and high temperature. The biocompatibility experiments of these films indicated that they were appropriated for culture of living neurons which displayed normal electrical behavior. PMID:28788667

  5. Engineering the Crystalline Morphology of Polymer Thin Films via Physical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Jeong, Hyuncheol; Arnold, Craig; Priestley, Rodney

    Thin-film growth via physical vapor deposition (PVD) has been successfully exploited for the delicate control of film structure for molecular and atomic systems. The application of such a high-energetic process to polymeric film growth has been challenged by chemical degradation. However, recent development of Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique opened up a way to deposit a variety of macromolecules in a PVD manner. Here, employing MAPLE technique to the growth of semicrystalline polymer thin films, we show the engineering of crystalline film morphology can be achieved via manipulation of substrate temperature. This is accomplished by exploiting temperature effect on crystallization kinetics of polymers. During the slow film growth crystallization can either be permitted or suppressed, and crystal thickness can be tuned via temperature modulation. In addition, we report that the crystallinity of polymer thin films may be significantly altered with deposition temperature in MAPLE processing. We expect that this ability to manipulate crystallization kinetics during polymeric film growth will open the possibility to engineer structure in thin film polymeric-based devices in ways that are difficult by other means.

  6. Structural and morphological properties of metallic thin films grown by pulsed laser deposition for photocathode application

    NASA Astrophysics Data System (ADS)

    Lorusso, A.; Gontad, F.; Caricato, A. P.; Chiadroni, E.; Broitman, E.; Perrone, A.

    2016-03-01

    In this work yttrium and lead thin films have been deposited by pulsed laser deposition technique and characterized by ex situ different diagnostic methods. All the films were adherent to the substrates and revealed a polycrystalline structure. Y films were uniform with a very low roughness and droplet density, while Pb thin films were characterized by a grain morphology with a relatively high roughness and droplet density. Such metallic materials are studied because they are proposed as a good alternative to copper and niobium photocathodes which are generally used in radiofrequency and superconducting radiofrequency guns, respectively. The photoemission performances of the photocathodes based on Y and Pb thin films have been also studied and discussed.

  7. Characterization of nanostructured ZnO thin films deposited through vacuum evaporation.

    PubMed

    Alvarado, Jose Alberto; Maldonado, Arturo; Juarez, Héctor; Pacio, Mauricio; Perez, Rene

    2015-01-01

    This work presents a novel technique to deposit ZnO thin films through a metal vacuum evaporation technique using colloidal nanoparticles (average size of 30 nm), which were synthesized by our research group, as source. These thin films had a thickness between 45 and 123 nm as measured by profilometry. XRD patterns of the deposited thin films were obtained. According to the HRSEM micrographs worm-shaped nanostructures are observed in samples annealed at 600 °C and this characteristic disappears as the annealing temperature increases. The films obtained were annealed from 25 to 1000 °C, showing a gradual increase in transmittance spectra up to 85%. The optical band gaps obtained for these films are about 3.22 eV. The PL measurement shows an emission in the red and in the violet region and there is a correlation with the annealing process.

  8. Characterization of nanostructured ZnO thin films deposited through vacuum evaporation

    PubMed Central

    Maldonado, Arturo; Juarez, Héctor; Pacio, Mauricio; Perez, Rene

    2015-01-01

    Summary This work presents a novel technique to deposit ZnO thin films through a metal vacuum evaporation technique using colloidal nanoparticles (average size of 30 nm), which were synthesized by our research group, as source. These thin films had a thickness between 45 and 123 nm as measured by profilometry. XRD patterns of the deposited thin films were obtained. According to the HRSEM micrographs worm-shaped nanostructures are observed in samples annealed at 600 °C and this characteristic disappears as the annealing temperature increases. The films obtained were annealed from 25 to 1000 °C, showing a gradual increase in transmittance spectra up to 85%. The optical band gaps obtained for these films are about 3.22 eV. The PL measurement shows an emission in the red and in the violet region and there is a correlation with the annealing process. PMID:25977868

  9. Optical and electrical properties of thin NiO films deposited by reactive magnetron sputtering and spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Parkhomenko, H. P.; Solovan, M. N.; Mostovoi, A. I.; Orletskii, I. G.; Parfenyuk, O. A.; Maryanchuk, P. D.

    2017-06-01

    Thin NiO films are deposited by reactive magnetron sputtering and spray pyrolysis. The main optical constants, i.e., refractive index n(λ), absorption coefficient α(λ), extinction coefficient k(λ), and thickness d, are determined. The temperature dependence of the resistance of thin films is found, and the activation energy of films deposited by different methods is determined.

  10. Atomic Layer-Deposited Titanium-Doped Vanadium Oxide Thin Films and Their Thermistor Applications

    NASA Astrophysics Data System (ADS)

    Wang, Shuyu; Yu, Shifeng; Lu, Ming; Liu, Mingzhao; Zuo, Lei

    2017-04-01

    Here we report the enhancement in the temperature coefficient of resistance (TCR) of atomic layer-deposited vanadium oxide thin films through the doping of titanium oxide. The Hall effect measurement provides a potential explanation for the phenomenon. The composition and morphology of the thin films are investigated by x-ray diffraction and scanning electron microscopy techniques. The high TCR, good uniformity, and low processing temperature of the material make it a good candidate for thermistor application.

  11. Development of a fluorescence based flux sensor for thin film growth and nanoparticle deposition

    SciTech Connect

    De Roo, Bert; Vervaele, Mattias; Locquet, Jean-Pierre; Rajala, Markku; Miller, Toni; Guillon, Herve; Seo, Jin Won

    2016-07-15

    An optical flux sensor, based on the fluorescence properties of materials and nanoparticles, has been developed to control the deposition rate in thin film deposition systems. Using a simple diode laser and a photomultiplier tube with a light filter, we report the detection of gallium atoms and CdSe-ZnS quantum dots. This setup has a high sensitivity and reproducibility.

  12. Photochemical Deposition of ZnS Thin Films by Intermittent Illumination

    NASA Astrophysics Data System (ADS)

    Ichimura, Masaya; Kobayashi, Ryohei; Miyawaki, Tetsuya

    2004-09-01

    We prepared ZnS thin films by photochemical deposition (PCD) using continuous and intermittent illumination. The aqueous solution used for the deposition contains ZnSO4 and Na2S2O3, and H2SO4 for pH adjustment. The solution is illuminated with light from an ultrahigh-pressure mercury arc lamp. When the illumination is continuous, the deposited film is black and not transparent because of excess zinc in the film. When the illumination is turned on and off periodically by a mechanical shutter, the deposited film becomes gradually transparent with increasing “off” time. The film deposited by the intermittent illumination has an optical absorption edge near 350 nm and shows photoconductivity.

  13. Structural and mechanical properties of CVD deposited titanium aluminium nitride (TiAlN) thin films

    NASA Astrophysics Data System (ADS)

    Das, Soham; Guha, Spandan; Ghadai, Ranjan; Kumar, Dhruva; Swain, Bibhu P.

    2017-06-01

    Titanium aluminium nitride (TiAlN) thin films were deposited by chemical vapour deposition using TiO2 powder, Al powder and N2 gas. The morphology and mechanical properties of the films were characterized by scanning electron microscopy and nanoindentation technique, respectively. The structural properties were characterized by Raman spectroscopy and X-ray diffraction. The XRD result shows TiAlN films are of NaCl-type metal nitride structure. Micro-Raman peaks of the TiAlN thin film were observed within 450 and 642 cm-1 for acoustic and optic range, respectively. A maximum hardness and Young modulus up to 22 and 272.15 GPa, respectively, were observed in the TiAlN film deposited at 1200 °C.

  14. Study of SnS2 thin film deposited by spin coating technique

    NASA Astrophysics Data System (ADS)

    Chaki, Sunil H.; Joshi, Hardikkumar J.; Tailor, Jiten P.; Deshpande, M. P.

    2017-07-01

    Thin film deposition of SnS2 was done by spin coating technique at ambient temperature. Deposition was done for different spin speed and spin time. The film thickness dependence on spin speed and spin time was studied. The spin speed was varied from 1000 rpm to 2000 rpm and spin time from 2 s to 6 s for constant speed of 1000 rpm. The elemental composition and crystal structure along with the phase of the as-deposited thin film was determined by the energy dispersive analysis of x-ray (EDAX) and x-ray diffraction (XRD) techniques respectively. The as-deposited thin film was found to be near stoichiometric and possess hexagonal crystal structure with determined lattice parameters in good agreement with the reported values. The crystallite size calculated from the XRD data using Scherrer’s formula and Hall-Williamson relation came out to be 9.77 nm and 6.49 nm, respectively. The transmission electron microscopy (TEM) study of spin deposited thin films showed the film to be continuous. Surface study of the as-deposited thin film was done by simple optical microscope and scanning electron microscope (SEM). The study showed that the deposited thin film to be flat and uniform without visible cracks and pores. The optical spectroscopy study of the as-deposited thin film showed that the optical bandgap value decreases with increase in film thickness. The d.c. electrical resistivity variation with temperature for spin coating as-deposited SnS2 film showed that the resistivity decreases with increase in temperature corroborating the semiconducting nature. The resistivity variation plot possesses two slopes. The temperature ranges showing two slopes lay between 300 to 383 K and 384 to 423 K having activation energy values for the two temperature ranges as 0.072 eV and 0.633 eV, respectively. The achieved results are deliberated in details.

  15. Optical and electrochemical properties of optically transparent, boron-doped diamond thin films deposited on quartz.

    PubMed

    Stotter, Jason; Zak, Jerzy; Behler, Zack; Show, Yoshiuki; Swain, Greg M

    2002-12-01

    The optical and electrochemical properties of transparent, boron-doped diamond thin film, deposited on quartz, are discussed. The films were deposited by microwave-assisted chemical vapor deposition, for 1-2 h, using a 0.5% CH4/H2 source gas mixture at 45 Torr and 600 W of power. A high rate of diamond nucleation was achieved by mechanically scratching the quartz. This pretreatment leads to the formation of a continuous film, in a short period of time, which consists of nanometer-sized grains of diamond. The thin-film electrode was characterized by cyclic voltammetry, atomic force microscopy, and UV-visible absorption spectrophotometry. The film's electrochemical response was evaluated using Ru(NH3)6(3+/2+) in 1 M KCl, Fe(CN)6(3-/4-) in 1 M KCl, and chlorpromazine (CPZ) in 10 mM HClO4. The film exhibited a low voltammetric background current and a stable and active voltammetric response for all three redox systems. The optical transparency of the polycrystalline film in the visible region was near 50% and fairly constant between 300 and 800 nm. The optical and electrical properties were extremely stable during 48-h exposure tests in various aqueous (HNO3, NaOH) solutions and nonaqueous (e.g., chlorinated) solvents. The properties were also extremely stable during anodic and cathodic potential cycling in harsh aqueous environments. This stability is in stark contrast to what was observed for an indium-doped tin oxide thin film coated on quartz. The spectroelectrochemical response (transmission mode) for CPZ was studied in detail, using a thin-layer spectroelectrochemical cell. Thin-layer voltammetry, potential step/ absorption measurements, and detection analytical figures of merit are presented. The results demonstrate that durable, stable, and optically transparent diamond thin films, with low electrical resistivity (approximately 0.026 omega x cm) laterally through the film, can be deposited on quartz.

  16. Deposition of electrochromic tungsten oxide thin films by plasma-enhanced chemical vapor deposition

    SciTech Connect

    Henley, W.B.; Sacks, G.J.

    1997-03-01

    Use of plasma-enhanced chemical vapor deposition (PECVD) for electrochromic WO{sub 3} film deposition is investigated. Oxygen, hydrogen, and tungsten hexafluoride were used as source gases. Reactant gas flow was investigated to determine the effect on film characteristics. High quality optical films were obtained at deposition rates on the order of 100 {angstrom}/s. Higher deposition rates were attainable but film quality and optical coherence degraded. Atomic emission spectroscopy (AES), was used to provide an in situ assessment of the plasma deposition chemistry. Through AES, it is shown that the hydrogen gas flow is essential to the deposition of the WO{sub 3} film. Oxygen gas flow and tungsten hexafluoride gas flow must be approximately equal for high quality films.

  17. Optical and mechanical properties of nanocrystalline ZrC thin films grown by pulsed laser deposition.

    DOE PAGES

    Craciun, D.; Socol, G.; Lambers, E.; ...

    2015-01-17

    Thin ZrC films (<500 nm) were grown on (100) Si substrates at a substrate temperature of 500 °C by the pulsed laser deposition (PLD) technique using a KrF excimer laser under different CH4 pressures. Glancing incidence X-ray diffraction showed that films were nanocrystalline, while X-ray reflectivity studies found out films were very dense and exhibited a smooth surface morphology. Optical spectroscopy data shows that the films have high reflectivity (>90%) in the infrared region, characteristic of metallic behavior. Nanoindentation results indicated that films deposited under lower CH4 pressures exhibited slightly higher nanohardness and Young modulus values than films deposited undermore » higher pressures. As a result, tribological characterization revealed that these films exhibited relatively high wear resistance and steady-state friction coefficients on the order of μ = 0.4.« less

  18. Optical and mechanical properties of nanocrystalline ZrC thin films grown by pulsed laser deposition.

    SciTech Connect

    Craciun, D.; Socol, G.; Lambers, E.; McCumiskey, E. J.; Taylor, C. R.; Martin, C.; Argibay, Nicolas; Craciun, V.; Tanner, D. B.

    2015-01-17

    Thin ZrC films (<500 nm) were grown on (100) Si substrates at a substrate temperature of 500 °C by the pulsed laser deposition (PLD) technique using a KrF excimer laser under different CH4 pressures. Glancing incidence X-ray diffraction showed that films were nanocrystalline, while X-ray reflectivity studies found out films were very dense and exhibited a smooth surface morphology. Optical spectroscopy data shows that the films have high reflectivity (>90%) in the infrared region, characteristic of metallic behavior. Nanoindentation results indicated that films deposited under lower CH4 pressures exhibited slightly higher nanohardness and Young modulus values than films deposited under higher pressures. As a result, tribological characterization revealed that these films exhibited relatively high wear resistance and steady-state friction coefficients on the order of μ = 0.4.

  19. Material and sensing properties of Pd-deposited WO3 thin films.

    PubMed

    Choi, Gwangpyo; Jin, Guanghu; Park, Si-Hyun; Lee, Woonyoung; Park, Jinseong

    2007-11-01

    The physicochemical and electrical properties of Pd-deposited WO3 thin films were investigated as a function of Pd thickness, annealing temperature, and operating temperature for application as a hydrogen gas sensor. WO3 thin films were deposited on an insulating material using a thermal evaporator. X-ray diffractometry (XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) were used to evaluate the crystal structure, microstructure, surface roughness, and chemical property of the films, respectively. The deposited films grew into polycrystalline WO3 with a rhombohedral structure after annealing at 500 degrees C. Adding Pd had no effect on the crystallinity, but suppressed the growth of WO3 grains. The Pd was scattered as isolated small spherical particles of PdO2 on the WO3 thin film after annealing at 500 degrees C, while it agglomerated as irregular large particles or diffused into the WO3 after annealing at 600 degrees C. PdO2 reduction under H2 and reoxidation under air were dependent on both the Pd deposition thickness and annealing conditions. The WO3 thin film with a 2-nm-thick Pd deposit showed a good response and recovery to H2 gas at a 250 degrees C operating temperature.

  20. Pulsed laser deposition of Bi2Te3-based thermoelectric thin films

    NASA Astrophysics Data System (ADS)

    Makala, Raghuveer S.; Jagannadham, K.; Sales, B. C.

    2003-09-01

    Thin films of p-type Bi0.5Sb1.5Te3, n-type Bi2Te2.7Se0.3, and n-type (Bi2Te3)90(Sb2Te3)5(Sb2Se3)5 (with 0.13 wt % SbI3) were deposited on substrates of mica and aluminum nitride (on silicon) using pulsed laser ablation at substrate temperatures between 300 °C to 500 °C. The films were characterized using x-ray diffraction and transmission electron microscopy for crystalline quality and epitaxial growth on the substrates. The surface morphology and microstructure were examined using scanning electron microscopy. X-ray mapping and energy-dispersive spectroscopy were performed to determine nonstoichiometry in the composition and homogeneity. The quality of the films, in terms of stoichiometric composition and crystal perfection, was studied as a function of growth temperature and laser fluence. The values of the Seebeck coefficient, electrical resistivity, and Hall mobility in the thin films were measured and compared with those in the bulk. Thermoelectric figure of merit of the films was evaluated from the measured parameters. Correlation of the thermoelectric properties, with the crystalline quality and stoichiometric composition of the films, showed the advantages of pulsed laser deposition of the multicomponent thermoelectric thin films. The results illustrate that laser physical vapor deposition is a suitable choice for deposition of multicomponent thermoelectric films. However, optimization of target composition, substrate temperature, and annealing of the films after deposition were found necessary to maintain the desired stoichiometry and low defect density. AlN/Si substrates provided better quality films compared to substrates of mica. Poor adhesion and cracking of the films on mica were found to be detrimental factors. Films deposited on AlN/Si substrates were found to show higher carrier mobility and higher values of Seebeck coefficient.

  1. Properties of NiO thin films deposited by intermittent spray pyrolysis process

    NASA Astrophysics Data System (ADS)

    Reguig, B. A.; Khelil, A.; Cattin, L.; Morsli, M.; Bernède, J. C.

    2007-02-01

    NiO thin films have been grown on glass substrates by intermittent spray pyrolysis deposition of NiCl 2·6H 2O diluted in distilled water, using a simple "perfume atomizer". The effect of the solution molarity on their properties was studied and compared to those of NiO thin films deposited with a classical spray system. It is shown that NiO thin films crystallized in the NiO structure are achieved after deposition. Whatever the precursor molarity, the grain size is around 25-30 nm. The crystallites are preferentially oriented along the (1 1 1) direction. All the films are p-type. However, the thickness and the conductivity of the NiO films depend on the precursor contraction. By comparison with the properties of films deposited by classical spray technique, it is shown that the critical precursor concentration, which induces strong thin films properties perturbations, is higher when a perfume atomizer is used. This broader stability domain can be attributed to better chlorides decomposition during the rest time used in the perfume atomizer technique.

  2. IN-SITU Diagnostics For Deposition And Processing Of High Tc Superconducting Thin Films

    NASA Astrophysics Data System (ADS)

    Venkatesan, T.

    1990-02-01

    The deposition of high quality superconducting thin films based on the metal oxides has given rise to a variety of needs for diagnostic techniques. These needs are primarily for monitoring, 1. the material ejection process from the target, 2. the ejected vapor interaction with the background oxygen, 3. the crystallization dynamics at the substrate and 4. post deposition analysis and processing of the film. This paper summarizes some of the recent work in this direction

  3. Optimization of the Automated Spray Layer-by-Layer Technique for Thin Film Deposition

    DTIC Science & Technology

    2010-06-01

    SUPPLEMENTARY NOTES 14. ABSTRACT The operational parameters of the automated Spray- LbL technique for thin film deposition have been investigated in...order to-identify their effects on film thickness and roughness. We use the automated Spray- LbL system developed at MIT by the Hammond lab to build...This interdiffusion is investigated using both the conventional dipped LbL and Spray- LbL deposition techniques. Interdiffusion is shown to be dependent

  4. Characteristics of CoxTi1-xO2 thin films deposited by MOCVD

    SciTech Connect

    McClure, A.; Kayani, A.; Idzerda, Y.U.; Arenholz, E.; Cruz, E.

    2008-05-09

    This paper deals with the growth and characterization of ferromagnetic cobalt doped TiO{sub 2} thin films deposited by liquid precursor metal organic chemical vapor deposition (MOCVD) using a new combination of the source materials Co(TMHD){sub 3}, tetrahydrofuran (THF), and titanium isopropoxide (TIP). An array of experiments reveals the intrinsic ferromagnetic nature of the grown films, and suggests that the magnetism is not generated by oxygen vacancies.

  5. Substrate dependent structural and magnetic properties of pulsed laser deposited Fe3O4 thin films.

    PubMed

    Goyal, Rajendra N; Kaur, Davinder; Pandey, Ashish K

    2010-12-01

    Nanocrystalline iron oxide thin films have been deposited on various substrates such as quartz, MgO(100), and Si(100) by pulsed laser deposition technique using excimer KrF laser (248 nm). The orientations, crystallite size and lattice parameters were studied using X-ray diffraction. The XRD results show that the films deposited on MgO and Si substrates are highly oriented and show only (400) and (311) reflections respectively. On the other hand, the orientation of the films deposited on quarts substrate changed from (311) to (400) with an increase in the substrate temperature from 400 degrees C to 600 degrees C, indicating thereby that the film growth direction is highly affected with nature of substrate and substrate temperature. The surface morphology of the deposited films was studied using Atomic Force Microscopy (AFM) and spherical ball like regular features of nanometer size grains were obtained. The magnetic properties were studied by Superconducting Quantum Interference Device (SQUID) magnetometer in the magnetic field +/- 6 Tesla. The magnetic field dependent magnetization (M-H) curves of all the Fe3O4 thin films measured at 5 K and 300 K show the ferrimagnetic nature. The electrochemical sensing of dopamine studied for these films shows that the film deposited on MgO substrate can be used as a sensing electrode.

  6. In situ monitoring of atomic layer deposition in nanoporous thin films using ellipsometric porosimetry.

    PubMed

    Dendooven, Jolien; Devloo-Casier, Kilian; Levrau, Elisabeth; Van Hove, Robbert; Sree, Sreeprasanth Pulinthanathu; Baklanov, Mikhail R; Martens, Johan A; Detavernier, Christophe

    2012-02-28

    Ellipsometric porosimetry (EP) is a handy technique to characterize the porosity and pore size distribution of porous thin films with pore diameters in the range from below 1 nm up to 50 nm and for the characterization of porous low-k films especially. Atomic layer deposition (ALD) can be used to functionalize porous films and membranes, e.g., for the development of filtration and sensor devices and catalytic surfaces. In this work we report on the implementation of the EP technique onto an ALD reactor. This combination allowed us to employ EP for monitoring the modification of a porous thin film through ALD without removing the sample from the deposition setup. The potential of in situ EP for providing information about the effect of ALD coating on the accessible porosity, the pore radius distribution, the thickness, and mechanical properties of a porous film is demonstrated in the ALD of TiO(2) in a mesoporous silica film.

  7. Investigations of LBMO thin films deposited on different substrates by electron beam evaporation

    NASA Astrophysics Data System (ADS)

    Seshendra Reddy, Ch.; Ashoka Reddy, Ch.; Sivasankar Reddy, A.; Sreedhara Reddy, P.

    2016-04-01

    La0.7Ba0.3MnO3 (LBMO) thin films were prepared on different substrates such as Si, MgO, and c-ZrO2 substrates at substrate temperature 1023 K using electron beam evaporation technique for first time. Through optimizing the preparation condition, the better film uniformity of thickness, composition, and temperature was achieved. To find the influence of substrates, we studied the structural, compositional, morphological, and electrical properties of LBMO thin films. All the LBMO films exhibited a single phase and good crystallinity with no impurity phases. Films deposited on MgO have high temperature coefficient of resistance (TCR) value with low transition temperature (245 K). Better TCR (4.09 %/K) value at room temperature is observed in LBMO films deposited on Si substrate.

  8. Direct current magnetron sputtering deposition of InN thin films

    NASA Astrophysics Data System (ADS)

    Cai, Xing-Min; Hao, Yan-Qing; Zhang, Dong-Ping; Fan, Ping

    2009-10-01

    In this paper, InN thin films were deposited on Si (1 0 0) and K9 glass by reactive direct current magnetron sputtering. The target was In metal with the purity of 99.999% and the gases were Ar (99.999%) and N 2 (99.999%). The properties of InN thin films were studied. Scanning electron microscopy (SEM) shows that the film surface is very rough and energy dispersive X-ray spectroscopy (EDX) shows that the film contains In, N and very little O. X-ray diffraction (XRD) and Raman scattering reveal that the film mainly contains hexagonal InN. The four-probe measurement shows that InN film is conductive. The transmission measurement demonstrates that the transmission of InN deposited on K9 glass is as low as 0.5% from 400 nm to 800 nm.

  9. Study of structural property of Co ferrite thin film grown by pulsed laser deposition technique

    NASA Astrophysics Data System (ADS)

    Nongjai, Razia; Khan, Shakeel; Ahmad, Hilal; Khan, Imran; Asokan, K.

    2012-06-01

    Thin film of Cobalt Ferrite was deposited on Si (1 0 0) substrate using Pulsed Laser Deposition (PLD) technique. The deposited film was characterized by X-ray Diffraction (XRD), X-ray reflectivity (XRR), Rutherford Backscattering Spectroscopy (RBS) and Raman Spectroscopy and was found to be single phase, textured along (1 1 1) directions and approximately matching the stoichoimetry of the target with negligible strain. The film had a very uniform and flat surface. Raman spectroscopy measurement further confirmed the formation of single phase cubic spinel structure. T2g Raman mode was missing from the spectra which may be due to cation redistribution and crystallite size effect.

  10. Thin films deposited by femtosecond pulsed laser ablation of tungsten carbide

    NASA Astrophysics Data System (ADS)

    De Bonis, A.; Teghil, R.; Santagata, A.; Galasso, A.; Rau, J. V.

    2012-09-01

    Ultra-short Pulsed Laser Deposition has been applied to the production of thin films from a tungsten carbide target. The gaseous phase obtained by the laser ablation shows a very weak primary plume, in contrast with a very strong secondary one. The deposited films, investigated by Scanning Electron Microscopy, Atomic Force Microscopy, X-Ray Photoelectron Spectroscopy and X-Ray Diffraction, present a mixture of WC and other phases with lower carbon content. All films are amorphous, independently from the substrate temperature. The characteristics of the deposits have been explained in terms of thermal evaporation and cooling rate of molten particles ejected from the target.

  11. Nanomechanical and microstructural characterization of sputter deposited ZnO thin films

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Vipul; Chowdhury, Rajib; Jayaganthan, R.

    2016-12-01

    The nano-mechanical properties of ZnO thin films deposited at different substrate temperature such as (RT) 25 °C, 100 °C, 200 °C, and 300 °C using DC-sputtering on Corning glass substrate were investigated. The ZnO thin films are found to be predominately c-axis (002) oriented. The crystal structure is sensitive to increasing substrate temperature and new set of crystal planes become visible at 300 °C as thin films become highly polycrystalline. The presence of (103) crystal plane is more pronounced with the increasing substrate temperature. However, high crystallinity and peak intensity ratio I(002)/I(103) (counts) is highest for thin films deposited at 100 °C, which is attributed for high hardness and better adhesive properties observed for ZnO thin films. Concomitantly, no major sudden burst of displacement 'pop-in' event in load-displacement curve of thin films observed during indentation, indicating the films are dense with low defects and adhered strongly to the substrate.

  12. Structure evolution of zinc oxide thin films deposited by unbalance DC magnetron sputtering

    SciTech Connect

    Aryanto, Didik; Marwoto, Putut; Sugianto; Sudiro, Toto; Birowosuto, Muhammad D.

    2016-04-19

    Zinc oxide (ZnO) thin films are deposited on corning glass substrates using unbalanced DC magnetron sputtering. The effect of growth temperature on surface morphology and crystallographic orientation of ZnO thin film is studied using atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The surface morphology and crystallographic orientation of ZnO thin film are transformed against the increasing of growth temperature. The mean grain size of film and the surface roughness are inversely and directly proportional towards the growth temperature from room temperature to 300 °C, respectively. The smaller grain size and finer roughness of ZnO thin film are obtained at growth temperature of 400 °C. The result of AFM analysis is in good agreement with the result of XRD analysis. ZnO thin films deposited in a series of growth temperatures have hexagonal wurtzite polycrystalline structures and they exhibit transformations in the crystallographic orientation. The results in this study reveal that the growth temperature strongly influences the surface morphology and crystallographic orientation of ZnO thin film.

  13. Monte Carlo Modeling of Thin Film Deposition: Factors that Influence 3D Islands

    SciTech Connect

    Gilmer, G H; Dalla Torre, J; Baumann, F H; Diaz de la Rubia, T

    2002-01-04

    In this paper we discuss the use of atomistic Monte Carlo simulations to predict film microstructure evolution. We discuss physical vapor deposition, and are primarily concerned with films that are formed by the nucleation and coalescence of 3D islands. Multi-scale modeling is used in the sense that information obtained from molecular dynamics and first principles calculations provide atomic interaction energies, surface and grain boundary properties and diffusion rates for use in the Monte Carlo model. In this paper, we discuss some fundamental issues associated with thin film formation, together with an assessment of the sensitivity of the film morphology to the deposition conditions and materials properties.

  14. On the microstructure of thin films grown by an isotropically directed deposition flux

    SciTech Connect

    Alvarez, R.; Romero-Gomez, P.; Gil-Rostra, J.; Yubero, F.; Palmero, A.; Gonzalez-Elipe, A. R.; Cotrino, J.

    2010-09-15

    The influence of isotropically directed deposition flux on the formation of the thin film microstructure at low temperatures is studied. For this purpose we have deposited TiO{sub 2} thin films by two different deposition techniques: reactive magnetron sputtering, in two different experimental configurations, and plasma enhanced chemical vapor deposition. The obtained results indicate that films grown under conditions where deposition particles do not possess a clear directionality, and in the absence of a relevant plasma/film interaction, present similar refractive indices no matter the deposition technique employed. The film morphology is also similar and consists of a granular surface topography and a columnarlike structure in the bulk whose diameter increases almost linearly with the film thickness. The deposition has been simulated by means of a Monte Carlo model, taking into account the main processes during growth. The agreement between simulations and experimental results indicates that the obtained microstructures are a consequence of the incorporation of low-energy, isotropically directed, deposition particles.

  15. Photocatalytic and optical properties of titanium dioxide thin films prepared by metalorganic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Khalifa, Z. S.; Mahmoud, S. A.

    2017-07-01

    Titanium dioxide thin films have been deposited by metalorganic chemical vapor deposition (MOCVD) over sodalime glass substrates at substrate temperatures ranging from 250 °C to 450 °C. The effect of deposition temperature on the structure and microstructure of the obtained films has been studied by x-rays diffraction (XRD) and scanning electron microscopy (SEM), respectively. Diffraction patterns show the existence of a pure anatase phase beside a texture change with the increase of deposition temperature. Micrographs show grain fragmentation with the increase in deposition temperature. UV-Vis. spectra have been recorded by spectrophotometery. The optical energy gap has been calculated for the deposited films from the spectrophotometrical data. Photocatalytic experiments have been carried out. The photocatalytic activity has been found to decrease with the increase in deposition temperature.

  16. Underpotential deposition-mediated layer-by-layer growth of thin films

    DOEpatents

    Wang, Jia Xu; Adzic, Radoslav R.

    2015-05-19

    A method of depositing contiguous, conformal submonolayer-to-multilayer thin films with atomic-level control is described. The process involves the use of underpotential deposition of a first element to mediate the growth of a second material by overpotential deposition. Deposition occurs between a potential positive to the bulk deposition potential for the mediating element where a full monolayer of mediating element forms, and a potential which is less than, or only slightly greater than, the bulk deposition potential of the material to be deposited. By cycling the applied voltage between the bulk deposition potential for the mediating element and the material to be deposited, repeated desorption/adsorption of the mediating element during each potential cycle can be used to precisely control film growth on a layer-by-layer basis. This process is especially suitable for the formation of a catalytically active layer on core-shell particles for use in energy conversion devices such as fuel cells.

  17. Effect of Post Deposition Annealing Treatments on Properties of AZO Thin Films for Schottky Diode Applications.

    PubMed

    Singh, Shaivalini; Park, Si-Hyun

    2016-01-01

    High-quality aluminum (Al) doped ZnO (AZO) thin films were deposited on silicon substrates by RF sputtering at room temperature. The deposited films were annealed from the temperatures 350 °C to 650 °C in pure nitrogen (N₂) ambient. The effects of annealing on the microstructural, optical and electrical properties of the AZO films were investigated. A detailed analysis by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Four Probe and Hall measurements was performed to study the properties of these AZO thin films. It was observed that all of the as-deposited and annealed AZO films have homogenous surfaces and hexagonal wurtzite structures with good crystalline quality. The study also suggested that there was an intermediate post annealing temperature (450 °C) at which the deposited ZnO film exhibit best surface characteristics. Pd/AZO Schottky devices were fabricated with 450 °C annealed AZO thin films and the parameters of Schottky devices were extracted from I-V characteristics. These results indicated that the Pd/AZO films were very much suitable for various optoelectronics applications particularly for metal semiconductor metal based UV detector application.

  18. Sputter deposition and characterization of lithium cobalt oxide thin films and their applications in thin-film rechargeable lithium batteries

    SciTech Connect

    Wang, B.; Bates, J.B.; Luck, C.F.; Sales, B.C.; Zuhr, R.A.; Robertson, J.D.

    1996-01-01

    Li Co oxide thin films were deposited by rf magnetron sputtering of a LiCoO{sub 2} target in a 3:1 Ar/O{sub 2} mixture gas. From proton-induced gamma-ray emission analysis and Rutherford backscattering spectrometry, the average composition of these films was determined to be Li{sub 1.15}CoO{sub 2.16}. X-ray powder diffraction patterns of films annealed in air at 500-700 C were consistent with regular rhombohedral structure of crystalline LiCoO{sub 2}. Discharge curves of thin film lithium cells with amoprohous LiCoO{sub 2} showed no obvious structural transition between 4.2 and 1.5 V. Shape of discharge curves of cells with polycrystalline cathodes were consistent with a two-phase voltage plateau at {similar_to}3.9 V with a relatively large capacity and two additional smaller plateaus at higher voltages. Cells with the 700 C annealed cathodes showed a capacity loss of {similar_to} after 1000 cycles between 4.2 and 3.0 V.

  19. In situ X-ray diffraction based investigation of crystallization in solution deposited PZT thin films

    NASA Astrophysics Data System (ADS)

    Nittala, Krishna

    Solution deposited PZT based thin films have potential applications in embedded decoupling capacitors and pulse discharge capacitors. During solution deposition, precursor solution is deposited onto a substrate to obtain an amorphous film. The film is then crystallized by heating it at a high temperature (˜600 - 700°C). Conditions during the crystallization anneal such as precursor stoichiometry in solution, heating rate and adhesion layer in the substrate are known to influence phase and texture evolution in these films. However, a mechanistic understanding of the changes taking place in these thin films during crystallization is lacking. A better understanding of the crystallization processes in these thin films could enable tailoring the properties of thin films to suit specific applications. To explore the crystallization process in solution deposited PZT thin films, high temperature in situ laboratory and synchrotron X-ray diffraction based techniques were developed. Taking advantage of the high X-ray flux available at synchrotron facilities such as beamline 6-ID-B, Advanced Photon Source, Argonne National Laboratory, crystalline phases formed in the thin films during crystallization at the high heating rates (0.5 -- 60°C/s) typically used during film processing could be measured. Using a 2-D detector for these measurements allowed the simultaneous measurement of both phase and texture information during crystallization. Analytical treatment of the unconventional diffraction geometry used during the synchrotron based measurements was performed to develop methodologies for quantitative estimation of texture components. The nominal lead content in the starting solutions and the heating rate used during crystallization was observed to influence the sequence of phases formed during crystallization of the films. In films crystallized at fast heating rates, titanium segregation, probably due to diffusion of titanium from the adhesion layer, was observed. To

  20. Pulsed laser deposition of tin oxide thin films for field emission studies

    NASA Astrophysics Data System (ADS)

    Jadhav, H.; Suryawanshi, S.; More, M. A.; Sinha, S.

    2017-10-01

    A comparative study of Pulsed Laser Deposition (PLD) based Tin Oxide (SnO2) thin films deposited at various substrate deposition temperature (Ts) has been performed. Surface morphology of the films was studied by Field Emission Scanning Electron Microscopy (FESEM) and surface composition of the films by X-ray PhotoelectronSpectroscopy (XPS) technique. X-ray diffraction (XRD) technique has been used to investigate crystalline nature of the deposited films. Field Emission (FE) properties of the SnO2 films were measured and a significantly low turn on field (2.1 V/μm) (field necessary to draw an emission current density of 10 μA/cm2) for films deposited at high substrate temperature (700 °C) was observed. Field enhancement factor estimated from FE studies was found to strongly depend on the surface morphology of the films. Overall good field emission current stability was observed for all SnO2 films. Dependence of FE properties on surface morphology, surface composition and deposition environment has been observed and analyzed systematically. Significantly low turn on field with high emission current density and field enhancement factor exhibited by films deposited when substrate was maintained at 700 °C has been mainly correlated to surface morphology and surface composition.

  1. Pulsed laser deposition of europium-doped multilayer thin films for spectral storage applications

    NASA Astrophysics Data System (ADS)

    Bezares, Francisco J.

    This thesis studies different Eu optical centers in MgS:Eu and CaS:Eu thin films produced by Chemically Controlled Pulse Laser Deposition (CCPLD) and evaluates their suitability for the development of spectral storage devices of the future. The produced thin films consist of one or more optically active layer(s), MgS:Eu, CaS:Eu or a similar material, and a corresponding ZnS capping layer that functions as a protecting barrier for the other layers and preserves their composition and integrity. Given that the synthesis of the materials used to produce the multilayer structures in this work proved a great challenge, careful attention was given to the optimization of all fabrication parameters. Mass Spectrometry was used during the deposition of the thin films and the data obtained resulted on improvements and optimization of the deposition process. Scanning electron microscopy studies of these thin films were conducted to study degradation upon long-term storage. Microscopy results show that the morphology of the produced thin films is correlated to the growth environment during deposition and deterioration of the deposited materials could be initiated by nano-gaps and cracks in the capping layer of the thin films. In addition to optical centers in MgS:Eu and CaS:Eu, new centers were created by changing the thin film growth environment inside a hi-vacuum chamber, modifying the composition of the ablation target material, or both. For example, introducing O2--, or alternatively HCl, inside the CCPLD chamber while producing MgS:Eu thin films results in the formation of impurity associated centers across lattice sites throughout the deposited structures. In another method of impurity doping studied, Cl-- and Na+ were introduced into the MgS:Eu and CaS:Eu lattices by mixing trace amounts of the impurity ions into these materials in polycrystalline form and making this mixture a deposition target by hi-pressure cold compression technique. The introduction of these impurity

  2. Structural and optical properties of PbS thin films grown by chemical bath deposition

    SciTech Connect

    Seghaier, S.; Kamoun, N.; Guasch, C.; Zellama, K.

    2007-09-19

    Lead sulphide thin films are grown on glass substrates at various deposition times tD, in the range of 40-60 min per step of 2 min, using the chemical bath deposition technique. X-ray diffraction and atomic force microscopy are used to characterize the film structure. The surface composition is analysed by Auger electron spectroscopy. It appears that the as-prepared thin films are polycrystalline with cubic structure. Nanometric scale crystallites are uniformly distributed on the surface. They exhibit almost a stoechiometric composition with a [Pb]/[S] ratio equal to 1.10. Optical properties are studied in the range of 300-3300 nm by spectrophotometric measurements. Analysis of the optical absorption data of lead sulphide thin layers reveals a narrow optical direct band gap equal to 0.46 eV for the layer corresponding to a deposition time equal to 60 min.

  3. Ultrathin Passivation of P-type silicon Surface by Atomic Layer Deposited Gallium Oxide Thin Films

    NASA Astrophysics Data System (ADS)

    Wen, J.; Guo, L. Q.; Tao, J.

    2017-02-01

    Surface passivation performances of Ga2O3 thin films deposited on p-type Czochralski Si wafers by atomic layer deposition (ALD) were investigated as a function of post-deposition annealing conditions. Minority carrier lifetimes were characterized by Semilab WT-2000PVN lifetime tester. The average effective minority carrier lifetime can reduce to 218.09 μs after annealed treatment at the temperatures of 650 °C for 3 min. It found that the surface recombination velocities of Ga2O3 thin film (3.4 nm and 7.6 nm) decrease to ∼30 cm/s and are saturated with the annealing temperature of 600 °C ∼700 °C. Such results indicate that Ga2O3 thin film show the functions of surface passivation for photovoltaic applications.

  4. Effect of angle of deposition on the Fractal properties of ZnO thin film surface

    NASA Astrophysics Data System (ADS)

    Yadav, R. P.; Agarwal, D. C.; Kumar, Manvendra; Rajput, Parasmani; Tomar, D. S.; Pandey, S. N.; Priya, P. K.; Mittal, A. K.

    2017-09-01

    Zinc oxide (ZnO) thin films were prepared by atom beam sputtering at various deposition angles in the range of 20-75°. The deposited thin films were examined by glancing angle X-ray diffraction and atomic force microscopy (AFM). Scaling law analysis was performed on AFM images to show that the thin film surfaces are self-affine. Fractal dimension of each of the 256 vertical sections along the fast scan direction of a discretized surface, obtained from the AFM height data, was estimated using the Higuchi's algorithm. Hurst exponent was computed from the fractal dimension. The grain sizes, as determined by applying self-correlation function on AFM micrographs, varied with the deposition angle in the same manner as the Hurst exponent.

  5. Chemical-bath deposition of ZnSe thin films: Process and material characterization

    SciTech Connect

    Dona, J.M.; Herrero, J.

    1995-03-01

    Chemical-bath deposition of ZnSe thin films from NH{sub 3}/NH{sub 2}-NH{sub 2}/SeC(NH{sub 2}){sub 2}/Na{sub 2}SO{sub 3}/ZnSO{sub 4} solutions has been studied. The effect of various process parameters on the growth and the film quality is presented. A first approach to a mechanistic interpretation of the chemical process, based on the influence of the process parameters on the film growth rate, is reported. The structural, optical, chemical, and electrical properties of the ZnSe thin-films deposited by this method have been studied. The electron diffraction (EDS) analysis shows that the films are microcrystalline with mixed cubic and hexagonal structure. EDS analysis has demonstrated that the films are highly stoichiometric. Scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy studies of the ZnSe thin films deposited by this method show that the films are continuous and homogeneous. Optical measurements have allowed the authors to detect the presence of the spin-orbit splitting effect in this material. Electrical conductivity measurements have shown the highly resistive nature of these films ({rho} {approximately} 10{sup 9} {Omega} cm).

  6. Chemical bath deposition of Cu{sub 3}BiS{sub 3} thin films

    SciTech Connect

    Deshmukh, S.G. Vipul, Kheraj; Panchal, A.K.

    2016-05-06

    First time, copper bismuth sulfide (Cu{sub 3}BiS{sub 3}) thin films were synthesized on the glass substrate using simple, low-cost chemical bath deposition (CBD) technique. The synthesized parameters such as temperature of bath, pH and concentration of precursors were optimized for the deposition of uniform, well adherent Cu{sub 3}BiS{sub 3} thin films. The optical, surface morphology and structural properties of the Cu{sub 3}BiS{sub 3} thin films were studied using UV-VIS-NIR spectra, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The as- synthesized Cu{sub 3}BiS{sub 3} film exhibits a direct band gap 1.56 to 1.58 eV having absorption coefficient of the order of 10{sup 5} cm{sup −1}. The XRD declares the amorphous nature of the films. SEM images shows films were composed of close-packed fine spherical nanoparticles of 70-80 nm in diameter. The chemical composition of the film was almost stoichiometric. The optical study indicates that the Cu{sub 3}BiS{sub 3} films can be applied as an absorber layer for thin film solar cells.

  7. Chemical bath deposition of Cu3BiS3 thin films

    NASA Astrophysics Data System (ADS)

    Deshmukh S., G.; Panchal A., K.; Vipul, Kheraj

    2016-05-01

    First time, copper bismuth sulfide (Cu3BiS3) thin films were synthesized on the glass substrate using simple, low-cost chemical bath deposition (CBD) technique. The synthesized parameters such as temperature of bath, pH and concentration of precursors were optimized for the deposition of uniform, well adherent Cu3BiS3 thin films. The optical, surface morphology and structural properties of the Cu3BiS3 thin films were studied using UV-VIS-NIR spectra, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The as- synthesized Cu3BiS3 film exhibits a direct band gap 1.56 to 1.58 eV having absorption coefficient of the order of 105 cm-1. The XRD declares the amorphous nature of the films. SEM images shows films were composed of close-packed fine spherical nanoparticles of 70-80 nm in diameter. The chemical composition of the film was almost stoichiometric. The optical study indicates that the Cu3BiS3 films can be applied as an absorber layer for thin film solar cells.

  8. Characterization of MAPLE deposited WO3 thin films for electrochromic applications

    NASA Astrophysics Data System (ADS)

    Boyadjiev, S. I.; Stefan, N.; Szilágyi, I. M.; Mihailescu, N.; Visan, A.; Mihailescu, I. N.; Stan, G. E.; Besleaga, C.; Iliev, M. T.; Gesheva, K. A.

    2017-01-01

    Tungsten trioxide (WO3) is a widely studied material for electrochromic applications. The structure, morphology and optical properties of WO3 thin films, grown by matrix assisted pulsed laser evaporation (MAPLE) from monoclinic WO3 nano-sized particles, were investigated for their possible application as electrochromic layers. A KrF* excimer (λ=248 nm, ζFWHM=25 ns) laser source was used in all experiments. The MAPLE deposited WO3 thin films were studied by atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXRD) and Fourier transform infrared spectroscopy (FTIR). Cyclic voltammetry measurements were also performed, and the coloring and bleaching were observed. The morpho-structural investigations disclosed the synthesis of single-phase monoclinic WO3 films consisting of crystalline nano-grains embedded in an amorphous matrix. All thin films showed good electrochromic properties, thus validating application of the MAPLE deposition technique for the further development of electrochromic devices.

  9. Effects of atomic collisions on the stoichiometry of thin films prepared by pulsed laser deposition.

    PubMed

    Packwood, Daniel M; Shiraki, Susumu; Hitosugi, Taro

    2013-07-19

    We present an analytical model to quantitatively study the effect of collisions between the atoms of a plume and the molecules of a surrounding gas on the nonstoichiometry of lithium-containing oxide thin films deposited using pulsed laser deposition. A comparison of the experimental data and the model ascertain the inevitable loss of the lighter cation, leading to a nonstoichiometric reduction in the content of lighter cations in the films. Our model is the first analytic model of collision-induced plume expansion that can explain the partial oxygen pressure dependence of the Li content of a thin film. These studies have important implications for collision effects that affect the growth of thin films containing both light and heavy elements.

  10. Growth and characteristics of tantalum oxide thin films deposited using thermionic vacuum arc technology

    NASA Astrophysics Data System (ADS)

    Vladoiu, Rodica; Ciupina, Victor; Mandes, Aurelia; Dinca, Virginia; Prodan, Madalina; Musa, Geavit

    2010-11-01

    Tantalum pentoxide (Ta2O5) thin films were synthesized using thermionic vacuum arc (TVA) technology. TVA is an original deposition method using a combination of anodic arc and electron gun system for the growth of thin films from solid precursors under vacuum of 10-6 Torr. The properties of the deposited Ta2O5 thin films were investigated in terms of wettability, refractive index, morphology, and structure. The surface free energy was determined by means of surface energy evaluation system indicating a hydrophilic character and the refractive index was measured by Filmetrics F20 device. The morphology was determined from bright field transmission electron microscopy (TEM) image performed by Philips CM 120 ST TEM system. It exhibits nanoparticles of 3-6 nm diameter smoothly distributed. Selected area electron diffraction pattern revealed the contrast fringes given by complex polycrystalline particles included in the amorphous film. The measured fringes could be indexed using monoclinic structure of Ta2O5.

  11. Thin films of energetic materials by physical vapor deposition: TATB and LLM-105

    NASA Astrophysics Data System (ADS)

    Williamson, David; Gymer, Sue; O'Conner, Colum; Hazelwood, Adam; Jardine, Andrew

    2015-06-01

    Thin films of energetic materials enable a diverse range of characterization measurements: structure, surface energy and adhesion, and even reactivity. Here we present a method to grow thin films by a physical vapor deposition method (sublimation) using a dedicated instrument which can operate at ultra-high vacuum. The approach enables fabrication of thin films of energetic materials that are otherwise difficult to process by traditional methods, for example because of their low solubility. The intention is to use this instrument as a platform for studying pure materials and co-deposited materials grown either as multi-layers or as co-crystals. Examples of TATB and LLM-105 film morphologies grown using this technique are presented.

  12. Thin films of energetic materials by physical vapor deposition: TATB and LLM-105

    NASA Astrophysics Data System (ADS)

    Williamson, D. M.; Gymer, S.; O'Connor, C.; Hazelwood, A.; Jardine, A. P.

    2017-01-01

    Thin films of energetic materials enable a diverse range of characterization measurements: structure, surface energy and adhesion, and even reactivity. Here we describe growth of thin films by a physical vapor deposition method (sublimation) using a dedicated instrument which can operate at ultra-high vacuum. The approach enables fabrication of thin films of energetic materials that are otherwise difficult to process by traditional methods, for example because of their low solubility. The intention is to use this instrument as a platform for studying pure materials and co-deposited materials grown either as multi-layers or as co-crystals. Examples of TATB and LLM-105 film morphologies grown using this technique are presented.

  13. Studies on VOx thin films deposited over Si3N4 coated Si substrates

    NASA Astrophysics Data System (ADS)

    Raj, P. Deepak; Gupta, Sudha; Sridharan, M.

    2015-06-01

    Vanadium oxide (VOx) thin films were deposited on to the silicon nitride (Si3N4) coated silicon (Si) substrate using reactive direct current magnetron sputtering at different substrate temperatures (Ts). The deposited films were characterized for their structural, morphological, optical and electrical properties. The average grain size of the deposited films was in the range of 95 to 178 nm and the strain varied from 0.071 to 0.054 %. The optical bandgap values of the films were evaluated using UV-Vis spectroscopy and lies in the range of 2.46 to 3.88 eV. The temperature coefficient of resistance (TCR) for the film deposited at 125 °C was -1.23%/°C with the sheet resistivity of 2.7 Ω.cm.

  14. Phenomenological Model of the Growth of Ultrasmooth Silver Thin Films Deposited with a Germanium Nucleation Layer.

    PubMed

    Zhang, Junce; Fryauf, David M; Garrett, Matthew; Logeeswaran, V J; Sawabe, Atsuhito; Islam, M Saif; Kobayashi, Nobuhiko P

    2015-07-21

    The structural properties of optically thin (15 nm) silver (Ag) films deposited on SiO2/Si(100) substrates with a germanium (Ge) nucleation layer were studied. The morphological and crystallographical characteristics of Ag thin films with different Ge nucleation layer thicknesses were assessed by cross-sectional transmission electron microscopy (XTEM), reflection high-energy electron diffraction (RHEED), X-ray diffractometry (XRD), grazing incidence X-ray diffractometry (GIXRD), X-ray reflection (XRR), and Fourier transform infrared spectroscopy (FTIR). The surface roughness of Ag thin films was found to decrease significantly by inserting a Ge nucleation layer with a thickness in the range of 1 to 2 nm (i.e., smoothing mode). However, as the Ge nucleation layer thickness increased beyond 2 nm, the surface roughness increased concomitantly (i.e., roughing mode). For the smoothing mode, the role of the Ge nucleation layer in the Ag film deposition is discussed by invoking the surface energy of Ge, the bond dissociation energy of Ag-Ge, and the deposition mechanisms of Ag thin films on a given characteristic Ge nucleation layer. Additionally, Ge island formation, the precipitation of Ge from Ag-Ge alloys, and the penetration of Ge into SiO2 are suggested for the roughing mode. This demonstration of ultrasmooth Ag thin films would offer an advantageous material platform with scalability for applications such as optics, plasmonics, and photonics.

  15. Antimony sulphide thin film as an absorber in chemically deposited solar cells

    NASA Astrophysics Data System (ADS)

    Messina, Sarah; Nair, M. T. S.; Nair, P. K.

    2008-05-01

    Antimony sulfide thin films (thickness, 500 nm) were deposited on chemically deposited CdS thin films (100 nm) obtained on 3 mm glass substrates coated with a transparent conductive coating of SnO2:F (TEC-15 with 15 Ω sheet resistance). Two different chemical formulations were used for depositing antimony sulfide films. These contained (i) antimony trichloride dissolved in acetone and sodium thiosulfate, and (ii) potassium antimony tartrate, triethanolamine, ammonia, thioacetamide and small concentrations of silicotungstic acid. The films were heated at 250 °C in nitrogen. The cell structure was completed by depositing a 200 nm p-type PbS thin film. Graphite paint applied on the PbS thin film and a subsequent layer of silver paint served as the p-side contact. The cell structure: SnO2:F/CdS/Sb2S3 (i or ii)/PbS showed open circuit voltage (Voc) of 640 mV and short circuit current density (Jsc) above 1 mA cm-2 under 1 kW m-2 tungsten-halogen radiation. Four cells, each of 1.7 cm2 area, were series-connected to give Voc of 1.6 V and a short circuit current of 4.1 mA under sunlight (1060 W m-2).

  16. RF magnetron sputter deposition and analysis of strontium-doped lead zirconate titanate thin films

    NASA Astrophysics Data System (ADS)

    Sriram, Sharath; Bhaskaran, Madhu; Holland, Anthony S.; Fardin, Ernest; Kandasamy, Sasikaran

    2006-01-01

    The paper investigates conditions for depositing perovskite-oriented strontium-doped lead zirconate titanate (PSZT) thin films using RF magnetron sputtering. PSZT is a material that can exhibit high piezoelectric and ferroelectric properties. The deposition was conducted using an 8/65/35 PSZT sputtering target. The effects of sputtering conditions and the deposition rates for films sputtered onto several surfaces (including gold and platinum coated substrates) were studied. Combinations of in-situ heating during sputtering and post-deposition Rapid Thermal Annealing (RTA) were performed and resulting phases determined. RTA was carried out in argon to observe their effects. The sputtered films were analyzed by Scanning Electron Microscopy (SEM), X-ray Diffractometry (XRD), and X-Ray Photoelectron Spectroscopy (XPS). Results show dramatic differences in the grain structure of the deposited films on the different surfaces. The stoichiometry of the sputtered films is demonstrated using XPS. In the case of gold and platinum coated substrates, sputtering was also carried out for different durations, to establish the growth rate of the film, and to observe the variation in grain size with sputtering duration. The deposited thin films were resistant to most chemical wet etchants and were Ion Beam Etched (IBE) at 19 nm/min.

  17. Continuous equilibrated growth of ordered block copolymer thin films by electrospray deposition.

    PubMed

    Hu, Hanqiong; Rangou, Sofia; Kim, Myungwoong; Gopalan, Padma; Filiz, Volkan; Avgeropoulos, Apostolos; Osuji, Chinedum O

    2013-04-23

    Deposition of block copolymer thin films is most often accomplished in a serial process where material is spin coated onto a substrate and subsequently annealed, either thermally or by solvent vapor, to produce a well-ordered morphology. Here we show that under appropriate conditions, well-ordered block copolymer films may be continuously grown under substrate equilibrated conditions by slow deposition of discrete subattoliter quantities of material using electrospray. We conduct time-resolved observations and investigate the effects of process parameters that underpin film morphology including solvent selectivity, substrate temperature, block-substrate selectivity, and flow rate of the feed solution. For a PEO cylinder-forming poly(styrene-b-ethylene oxide) block copolymer, we uncover a wide temperature window from 90 to 150 °C and an ideal flow rate of 2 μL/min for ordered film deposition from dilute acetone solutions. PEO cylinders aligned with their long axes perpendicular to the film-air interface at optimal spray conditions. Using poly(styrene-b-methyl methacrylate) deposited onto neutrally selective surfaces, we show that the substrate-equilibrated process results in vertically oriented microdomains throughout the film, indicating a preservation of the initial substrate-dictated morphology during the film deposition. Electrospray offers a new and potentially exciting route for controlled, continuous growth of block copolymer thin films and manipulation of their microstructure.

  18. Mössbauer study of electrochemically deposited amorphous iron-sulfide-oxide thin films

    NASA Astrophysics Data System (ADS)

    Ichimura, Masaya; Kajima, Takahiro; Kawai, Shoichi; Mibu, Ko

    2016-03-01

    Iron-sulfide-oxide thin films, which are promising candidates for solar cell materials, were deposited by electrochemical deposition. As-deposited and annealed films were characterized by Mössbauer spectroscopy, X-ray diffraction (XRD), and Raman scattering at room temperature. The as-deposited film is amorphous, and the oxygen content is about 1/4 of the sulfur content (S/Fe ≈ 1.5, O/Fe ≈ 0.4). The Mössbauer spectrum for the as-deposited film is a doublet with a broad line profile having hyperfine parameters similar to those of FeS2 pyrite or marcasite. This indicates that Fe atoms are in the Fe2+ low-spin state, as in FeS2.

  19. Effects of deposition temperature on the mechanical and physical properties of silicon nitride thin films

    NASA Astrophysics Data System (ADS)

    Walmsley, B. A.; Liu, Y.; Hu, X. Z.; Bush, M. B.; Winchester, K. J.; Martyniuk, M.; Dell, J. M.; Faraone, L.

    2005-08-01

    This study investigates the mechanical and physical properties of low-temperature plasma-enhanced chemical-vapor-deposited silicon nitride thin films, with particular respect to the effect of deposition temperature. The mechanical properties of the films were evaluated by both nanoindentation and microcantilever beam-bending techniques. The cantilever beam specimens were fabricated from silicon nitride thin films deposited on (100) silicon wafer by bulk micromachining. The density of the films was determined from quartz crystal microbalance measurements, as well as from the resonant modes of the cantilever beams, which were mechanically excited using an atomic force microscope. It was found that both the Young's modulus and density of the films were significantly reduced with decreasing deposition temperature. The decrease in Young's modulus is attributed to the decreasing material density. The decrease in density with decreasing deposition temperature is believed to be due to the slower diffusion rates of the deposited species, which retarded the densification of the film during the deposition process.

  20. Structural and optical characterizations of chemically deposited cadmium selenide thin films

    SciTech Connect

    Khomane, A.S.

    2011-10-15

    Highlights: {yields} CdSe thin films deposited first time using formic acid as a complexing agent. {yields} The deposited thin films were characterized by XRD, SEM, UV-vis-NIR and electrical techniques. {yields} X-ray diffraction analysis shows presence of zinc blende crystal structure. -- Abstract: Synthesis of cadmium selenide thin films by CBD method has been presented. The deposited film samples were subjected to XRD, SEM, UV-vis-NIR and TEP characterization. X-ray diffraction analysis showed that CdSe film sample crystallized in zinc blende or cubic phase structure. SEM studies reveal that the grains are spherical in shape and uniformly distributed all over the surface of the substrates. The optical band gap energy of as deposited film sample was found to be in the order of 1.8 eV. The electrical conductivity of the film sample was found to be 10{sup -6} ({Omega} cm){sup -1} with n-type of conduction mechanism.

  1. Sequential pulsed laser deposition of homoepitaxial SrTiO3 thin films

    NASA Astrophysics Data System (ADS)

    Groenendijk, D. J.; Gariglio, S.

    2016-12-01

    The control of thin film stoichiometry is of primary relevance to achieve desired functionality. Pulsed laser deposition ablating from binary-oxide targets (sequential deposition) can be applied to precisely control the film composition, offsetting the importance of growth conditions on the film stoichiometry. In this work, we demonstrate that the cation stoichiometry of SrTiO3 thin films can be finely tuned by sequential deposition from SrO and TiO2 targets. Homoepitaxial SrTiO3 films were deposited at different substrate temperatures and Ti/Sr pulse ratios, allowing the establishment of a growth window for stoichiometric SrTiO3. The growth kinetics and nucleation processes were studied by reflection high-energy electron diffraction and atomic force microscopy, providing information about the growth mode and the degree of off-stoichiometry. At the optimal (stoichiometric) growth conditions, films exhibit atomically flat surfaces, whereas off-stoichiometry is accommodated by crystal defects, 3D islands, and/or surface precipitates depending on the substrate temperature and the excess cation. This technique opens the way to precisely control stoichiometry and doping of oxide thin films.

  2. Anomalous scaling behavior and surface roughening in molecular thin-film deposition

    SciTech Connect

    Yim, S.; Jones, T. S.

    2006-04-15

    The thin film growth dynamics of a molecular semiconductor, free-base phthalocyanine (H{sub 2}Pc), deposited by organic molecular beam deposition, has been studied by atomic force microscopy (AFM) and height difference correlation function (HDCF) analysis. The measured dynamic scaling components ({alpha}{sub loc}=0.61{+-}0.12, {beta}=1.02{+-}0.08, and 1/z=0.72{+-}0.13) are consistent with rapid surface roughening and anomalous scaling behavior. A detailed analysis of AFM images and simple growth models suggest that this behavior arises from the pronounced upward growth of crystalline H{sub 2}Pc mounds during the initial stages of thin film growth.

  3. DCEMS Study of Thin Stainless Steel Films Deposited by RF Sputtering of AISI316L

    SciTech Connect

    Nomura, K.; Iio, S.; Ujihira, Y.; Terai, T.

    2005-04-26

    Thin stainless steel films were prepared on SiO2/Si plate heated at 100 deg. C and 400 deg. C using AISI316L as target, by a RF magnetron Ar sputtering method. RF sputtered-deposited films and the oxidized surface layers by post heating were characterized by depth selective conversion electron Moessbauer spectroscopy (DCEMS) using a He+5%CH4 gas proportional counter. The as-deposited films consisted of magnetic phases, the magnetic orientation of which had a tendency to be perpendicular to the surface of the film. In the case of the deposited films at substrate temperature of 100 deg. C, a small amount of Fe2O3 and ferritic stainless steel formed by post-heating in air. A magnetic subcomponent and a austenite phase were formed in the films deposited at substrate temperature of 400 deg. C. {alpha}-Fe2O3 and magnetite formed easily on the top and middle layers of the films by post-heating in air. The oxide states of the films deposited at different temperatures of substrate were clearly distinguished by post-heating. Thus it was found by DCEMS that the structures of the deposited films were strongly affected by the preparation method and the temperature of the substrate.

  4. Preparation of vanadium oxide thin films modified with Ag using a hybrid deposition configuration

    NASA Astrophysics Data System (ADS)

    Gonzalez-Zavala, F.; Escobar-Alarcón, L.; Solís-Casados, D. A.; Rivera-Rodríguez, C.; Basurto, R.; Haro-Poniatowski, E.

    2016-04-01

    The application of a hybrid deposition configuration, formed by the interaction of a laser ablation plasma with a flux of atomic vapor, to deposit vanadium oxide thin films modified with different amounts of silver, is reported. The effect of the amount of Ag incorporated in the films on their structural, morphological, compositional and optical properties was studied. The obtained results reveal that films with variable Ag content from 11.7 to 24.6 at.% were obtained. Depending on the silver content, the samples show very different surface morphologies. Optical characterization indicates the presence of nanostructures of Ag. Thin films containing silver exhibit better photocatalytic performances than unmodified V2O5 films. Raman spectra reveal that as the silver content is increased, the signals associated with V2O5 disappear and new modes attributed mainly to silver vanadates appear suggesting the formation of ternary compounds.

  5. Photovoltaic properties of ferroelectric BaTiO3 thin films RF sputter deposited on silicon

    NASA Technical Reports Server (NTRS)

    Dharmadhikari, V. S.; Grannemann, W. W.

    1982-01-01

    Ferroelectric thin films of BaTiO3 have been successfully deposited on n-type silicon substrates at temperatures above 500 C by RF sputtering in an O2/Ar atmosphere. Analysis by X-ray diffraction patterns show that films deposited at room temperature are amorphous. At temperatures above 500 C, crystalline BaTiO3 films with a tetragonal structure are obtained. The polarization-electric field (P-E) hysteresis loops and a broad peak in the dielectric constant versus temperature curve at Curie point indicate that the RF sputtered BaTiO3 films are ferroelectric. An anomalous photovoltaic effect is observed in these thin films which is related to the remanent polarization of the material. The results on open-circuit and short-circuit measurements provide an important basis for a better understanding of the role of photovoltaic field, photovoltaic current, and the pyroelectric properties in photoferroelectric domain switching.

  6. Uses of ion bombardment in thin-film deposition

    SciTech Connect

    Erck, R.A.; Fenske, G.R.; Erdemir, A.

    1990-10-01

    Use of plasma- and ion-beam-modified surfaces and surface coatings in continually expanding in engineering disciplines. The purpose of these modifications and treatments is to impart favorable properties, such as wear resistance and lubricity, to the surfaces, while at the same time retaining the strength or toughness of the bulk materials. Energetic-ion bombardment can be used to modify the structural and chemical properties of surfaces or applied coatings. Ion-implantation has been used for many years, and recently, other surface-modification techniques, among them ion-beam mixing and ion-beam-assisted deposition, have attracted attention because they permit application of highly adherent lubricious and wear-resistant films. In this paper, ion-beam techniques are described from the viewpoint of ion-surface interactions, and some avenues for the engineering of tribological surfaces are presented. 100 refs., 4 figs.

  7. ZnS thin films deposition by thermal evaporation for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Benyahia, K.; Benhaya, A.; Aida, M. S.

    2015-10-01

    ZnS thin films were deposited on glass substrates by thermal evaporation from millimetric crystals of ZnS. The structural, compositional and optical properties of the films are studied by X-ray diffraction, SEM microscopy, and UV-VIS spectroscopy. The obtained results show that the films are pin hole free and have a cubic zinc blend structure with (111) preferential orientation. The estimated optical band gap is 3.5 eV and the refractive index in the visible wavelength ranges from 2.5 to 1.8. The good cubic structure obtained for thin layers enabled us to conclude that the prepared ZnS films may have application as buffer layer in replacement of the harmful CdS in CIGS thin film solar cells or as an antireflection coating in silicon-based solar cells.

  8. Amorphous indium gallium zinc oxide thin film grown by pulse laser deposition technique

    SciTech Connect

    Mistry, Bhaumik V. Joshi, U. S.

    2016-05-23

    Highly electrically conducting and transparent in visible light IGZO thin film were grown on glass substrate at substrate temperature of 400 C by a pulse laser deposition techniques. Structural, surface, electrical, and optical properties of IGZO thin films were investigated at room temperature. Smooth surface morphology and amorphous nature of the film has been confirmed from the AFM and GIXRD analysis. A resistivity down to 7.7×10{sup −3} V cm was reproducibly obtained while maintaining optical transmission exceeding 70% at wavelengths from 340 to 780 nm. The carrier densities of the film was obtain to the value 1.9×10{sup 18} cm{sup 3}, while the Hall mobility of the IGZO thin film was 16 cm{sup 2} V{sup −1}S{sup −1}.

  9. Properties of antimony doped ZnO thin films deposited by spray pyrolysis technique

    SciTech Connect

    Sadananda Kumar, N. Bangera, Kasturi V.; Shivakumar, G. K.

    2015-07-15

    Antimony (Sb) doped zinc oxide (ZnO) thin films were deposited on the glass substrate at 450°C using spray pyrolysis technique. Effect of Sb doping on surface morphology structural, optical and electrical properties were studied. X-ray diffraction (XRD) analysis showed that both the undoped and doped ZnO thin films are polycrystalline in nature with (101) preferred orientation. SEM analysis showed a change in surface morphology of Sb doped ZnO thin films. Doping results in a marked increase in conductivity without affecting the transmittance of the films. ZnO films prepared with 3 at % Sb shows the lowest resistivity of 0.185 Ohm cm with a Hall mobility of 54.05 cm{sup 2} V{sup –1} s{sup –1}, and a hole concentration of 6.25 × 10{sup 17} cm{sup –3}.

  10. Epitaxial niobium dioxide thin films by reactive-biased target ion beam deposition

    SciTech Connect

    Wang, Yuhan; Comes, Ryan B.; Kittiwatanakul, Salinporn; Wolf, Stuart A.; Lu, Jiwei

    2015-03-01

    Epitaxial NbO2 thin films were synthesized on Al2O3 (0001) substrates via reactive bias target ion beam deposition. X-ray diffraction and Raman spectra were used to confirm the tetragonal phase of pure NbO2. Through XPS, it was found that there was a ~ 1.3 nm thick Nb2O5 layer on the surface and the bulk of the thin film was NbO2. The epitaxial relationship between NbO2 film and substrate was determined. Electrical transport measurement as a function of temperature showed that the conduction mechanism could be described by variable range hopping mechanism.

  11. Determination of dispersion parameters of thermally deposited CdTe thin film

    SciTech Connect

    Dhimmar, J. M. Desai, H. N.; Modi, B. P.

    2016-05-23

    Cadmium Telluride (CdTe) thin film was deposited onto glass substrates under a vacuum of 5 × 10{sup −6} torr by using thermal evaporation technique. The prepared film was characterized for dispersion analysis from reflectance spectra within the wavelength range of 300 nm – 1100 nm which was recorded by using UV-Visible spectrophotometer. The dispersion parameters (oscillator strength, oscillator wavelength, high frequency dielectric constant, long wavelength refractive index, lattice dielectric constant and plasma resonance frequency) of CdTe thin film were investigated using single sellimeir oscillator model.

  12. Development of aerosol assisted chemical vapor deposition for thin film fabrication

    NASA Astrophysics Data System (ADS)

    Maulana, Dwindra Wilham; Marthatika, Dian; Panatarani, Camellia; Mindara, Jajat Yuda; Joni, I. Made

    2016-02-01

    Chemical vapor deposition (CVD) is widely used to grow a thin film applied in many industrial applications. This paper report the development of an aerosol assisted chemical vapor deposition (AACVD) which is one of the CVD methods. Newly developed AACVD system consists of a chamber of pyrex glass, two wire-heating elements placed to cover pyrex glass, a substrate holder, and an aerosol generator using an air brush sprayer. The temperature control system was developed to prevent condensation on the chamber walls. The control performances such as the overshoot and settling time were obtained from of the developed temperature controller. Wire-heating elements were controlled at certain setting value to heat the injected aerosol to form a thin film in the substrate. The performance of as-developed AACVD system tested to form a thin film where aerosol was sprayed into the chamber with a flow rate of 7 liters/minutes, and vary in temperatures and concentrations of precursor. The temperature control system have an overshoot around 25 °C from the desired set point temperature, very small temperature ripple 2 °C and a settling time of 20 minutes. As-developed AACVD successfully fabricated a ZnO thin film with thickness of below 1 µm. The performances of system on formation of thin films influenced by the generally controlled process such as values of setting temperature and concentration where the aerosol flow rate was fixed. Higher temperature was applied, the more uniform ZnO thin films were produced. In addition, temperature of the substrate also affected on surface roughness of the obtained films, while concentration of ZnO precursor determined the thickness of produce films. It is concluded that newly simple AACVD can be applied to produce a thin film.

  13. Raman study of oriented ZnO thin films deposited by sol-gel method

    NASA Astrophysics Data System (ADS)

    Yahia, S. Ben; Znaidi, L.; Kanaev, A.; Petitet, J. P.

    2008-12-01

    ZnO films with preferred orientation along the (0 0 2) plane were successfully deposited by the sol-gel method using Zn(CH 3COO) 2·2H 2O as starting material and inorganic precursor. A homogeneous and stable solution was prepared by dissolving the zinc acetate in a solution of ethanol and monoethanolamine. Thin films are obtained by spin-coating on glass substrates. ZnO films were obtained by preheating the spin-coated films at 300 °C for 10 min after each coating and postheating upto 550 °C for 2 h. The as-deposited films are transformed into mono-oriented ZnO upon thermal treatment. The films consist of spongy particles aggregates with an uniform size and homogenous surface. The films aim to be used in optoelectronic devices. Raman spectroscopy from ZnO films and deposit solutions has been investigated. New Raman results of the deposit solution suggest that Zn-O bond forms first in solution and that these entities play the role of germs initiating the crystallization mechanisms during films annealing. Raman spectra of the annealed films show the presence of a compressive stress within the film structure.

  14. Deposition and Characterization of Thin Films on Metallic Substrates

    NASA Technical Reports Server (NTRS)

    Gatica, Jorge E.

    2005-01-01

    A CVD method was successfully developed to produce conversion coatings on aluminum alloys surfaces with reproducible results with a variety of precursors. A well defined protocol to prepare the precursor solutions formulated in a previous research was extended to other additives. It was demonstrated that solutions prepared following such a protocol could be used to systematically generate protective coatings onto aluminum surfaces. Experiments with a variety of formulations revealed that a refined deposition protocol yields reproducible conversion coatings of controlled composition. A preliminary correlation between solution formulations and successful precursors was derived. Coatings were tested for adhesion properties enhancement for commercial paints. A standard testing method was followed and clear trends were identified. Only one precursors was tested systematically. Anticipated work on other precursors should allow a better characterization of the effect of intermetallics on the production of conversion/protective coatings on metals and ceramics. The significance of this work was the practical demonstration that chemical vapor deposition (CVD) techniques can be used to systematically generate protective/conversion coating on non-ferrous surfaces. In order to become an effective approach to replace chromate-based pre- treatment processes, namely in the aerospace or automobile industry, the process parameters must be defined more precisely. Moreover, the feasibility of scale-up designs necessitates a more comprehensive characterization of the fluid flow, transport phenomena, and chemical kinetics interacting in the process. Kinetic characterization showed a significantly different effect of magnesium-based precursors when compared to iron-based precursors. Future work will concentrate on refining the process through computer simulations and further experimental studies on the effect of other transition metals to induce deposition of conversion/protective films

  15. Growth, structure and stability of sputter-deposited MoS2 thin films.

    PubMed

    Kaindl, Reinhard; Bayer, Bernhard C; Resel, Roland; Müller, Thomas; Skakalova, Viera; Habler, Gerlinde; Abart, Rainer; Cherevan, Alexey S; Eder, Dominik; Blatter, Maxime; Fischer, Fabian; Meyer, Jannik C; Polyushkin, Dmitry K; Waldhauser, Wolfgang

    2017-01-01

    Molybdenum disulphide (MoS2) thin films have received increasing interest as device-active layers in low-dimensional electronics and also as novel catalysts in electrochemical processes such as the hydrogen evolution reaction (HER) in electrochemical water splitting. For both types of applications, industrially scalable fabrication methods with good control over the MoS2 film properties are crucial. Here, we investigate scalable physical vapour deposition (PVD) of MoS2 films by magnetron sputtering. MoS2 films with thicknesses from ≈10 to ≈1000 nm were deposited on SiO2/Si and reticulated vitreous carbon (RVC) substrates. Samples deposited at room temperature (RT) and at 400 °C were compared. The deposited MoS2 was characterized by macro- and microscopic X-ray, electron beam and light scattering, scanning and spectroscopic methods as well as electrical device characterization. We find that room-temperature-deposited MoS2 films are amorphous, of smooth surface morphology and easily degraded upon moderate laser-induced annealing in ambient conditions. In contrast, films deposited at 400 °C are nano-crystalline, show a nano-grained surface morphology and are comparatively stable against laser-induced degradation. Interestingly, results from electrical transport measurements indicate an unexpected metallic-like conduction character of the studied PVD MoS2 films, independent of deposition temperature. Possible reasons for these unusual electrical properties of our PVD MoS2 thin films are discussed. A potential application for such conductive nanostructured MoS2 films could be as catalytically active electrodes in (photo-)electrocatalysis and initial electrochemical measurements suggest directions for future work on our PVD MoS2 films.

  16. Uniform GaN thin films grown on (100) silicon by remote plasma atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Shih, Huan-Yu; Lin, Ming-Chih; Chen, Liang-Yih; Chen, Miin-Jang

    2015-01-01

    The growth of uniform gallium nitride (GaN) thin films was reported on (100) Si substrate by remote plasma atomic layer deposition (RP-ALD) using triethylgallium (TEG) and NH3 as the precursors. The self-limiting growth of GaN was manifested by the saturation of the deposition rate with the doses of TEG and NH3. The increase in the growth temperature leads to the rise of nitrogen content and improved crystallinity of GaN thin films, from amorphous at a low deposition temperature of 200 °C to polycrystalline hexagonal structures at a high growth temperature of 500 °C. No melting-back etching was observed at the GaN/Si interface. The excellent uniformity and almost atomic flat surface of the GaN thin films also infer the surface control mode of the GaN thin films grown by the RP-ALD technique. The GaN thin films grown by RP-ALD will be further applied in the light-emitting diodes and high electron mobility transistors on (100) Si substrate.

  17. Nanocrystalline CuInSSe thin films by chemical bath deposition technique

    SciTech Connect

    Shrotriya, Vipin Rajaram, P.

    2016-05-06

    Crystalline CuInSSe thin films have been deposited on glass substrate by chemical bath deposition technique. The CuCl{sub 2}, InCl{sub 3}, thiourea and SeO{sub 2} were used as source materials for the Cu{sup 2+}, In{sup 3+}, S{sup 2−} and Se{sup 2−} ions and the Cu/In ratio was kept at 1.0. EDC was used as a complexing agent. The XRD, Scanning Electron Microscope (SEM), Energy Dispersive Analysis of X-Ray (EDAX) and Optical transmission studies were used for structural analysis, surface morphology, elemental analysis and optical band gap, of the grown thin films respectively. The deposition parameters such as pH, deposition temperature and deposition time were optimized.

  18. Nanocrystalline CuInSSe thin films by chemical bath deposition technique

    NASA Astrophysics Data System (ADS)

    Shrotriya, Vipin; Rajaram, P.

    2016-05-01

    Crystalline CuInSSe thin films have been deposited on glass substrate by chemical bath deposition technique. The CuCl2, InCl3, thiourea and SeO2 were used as source materials for the Cu2+, In3+, S2- and Se2- ions and the Cu/In ratio was kept at 1.0. EDC was used as a complexing agent. The XRD, Scanning Electron Microscope (SEM), Energy Dispersive Analysis of X-Ray (EDAX) and Optical transmission studies were used for structural analysis, surface morphology, elemental analysis and optical band gap, of the grown thin films respectively. The deposition parameters such as pH, deposition temperature and deposition time were optimized.

  19. Chemical vapor deposition of diamond thin films on titanium silicon carbide

    NASA Astrophysics Data System (ADS)

    Yang, Songlan

    2008-10-01

    Chemical vapor deposition (CVD) has been the main method for synthesizing diamond thin films on hetero substrate materials since 1980s. It has been well acknowledged that both nucleation and growth of diamond on non-diamond surfaces without pre-treatment are very difficult and slow. Furthermore, the weak adhesion between the diamond thin films and substrates has been a major problem for widespread application of diamond thin films. Up to now, Si has been the most frequently used substrate for the study of diamond thin films and various methods, including bias and diamond powder scratching, have been applied to enhance diamond nucleation density. In the present study, nucleation and growth of diamond thin films on Ti3SiC2, a newly developed ceramic-metallic material, using Microwave Plasma Enhanced (MPE) and Hot- Filament (HF) CVD reactors were carried out. In addition, synchrotron-based Near Edge Extended X-Ray Absorption Fine Structure Spectroscopy (NEXAFS) was used to identify the electronic and chemical structures of various NCD films. The results from MPECVD showed that a much higher diamond nucleation density and a much higher film growth rate can be obtained on Ti3SiC2 compared with on Si. Consequently, nanocrystalline diamond (NCD) thin films were feasibly synthesized on Ti3SiC2 under the typical conditions for microcrystalline diamond film synthesis. Furthermore, the diamond films on Ti3SiC 2 exhibited better adhesion than on Si. The early stage growth of diamond thin films on Ti3SiC2 by HFCVD indicated that a nanowhisker-like diamond-graphite composite layer, different from diamond nucleation on Si, initially formed on the surface of Ti3SiC2, which resulted in high diamond nucleation density. These results indicate that Ti3SiC 2 has great potentials to be used both as substrates and interlayers on metals for diamond thin film deposition and application. This research may greatly expand the tribological application of both Ti3SiC 2 and diamond thin films

  20. Influence of the Ultrasonic Vibration on Chemical Bath Deposition of ZnS Thin Films

    NASA Astrophysics Data System (ADS)

    Liu, Qi; Mao, Guobing

    Chemical bath deposition (CBD) and ultrasonic chemical bath deposition (US-CBD) of ZnS thin films from NH4OH/SC(NH2)2/ZnSO4 solutions have been studied. The influence of the ultrasonic vibration on properties of ZnS thin films has been investigated. The growth rate, structure, and properties of ZnS thin film deposited by different CBD techniques were studied using X-ray diffractometer (XRD), scanning electron microscopy (SEM), and atomic force microscope (AFM). The results show that the growth rate of US-CBD is slower than that of CBD. The XRD analysis of as-deposited ZnS films shows that the films are both cubic ZnS structure and the crystallinity of US-CBD ZnS film is higher than that of CBD ZnS film. SEM studies indicate that adhesion particles on the US-CBD ZnS surface are fewer than that on the CBD ZnS surface. Moreover, the film prepared by US-CBD is homogeneous and with high compactness. The rms roughness (Rrms) value of CBD ZnS film is higher than that of US-CBD. Transmission measurement shows that the optical transmittance of US-CBD ZnS is higher than that of CBD ZnS, and the optical transmittance is above 90% when the wavelength is over 470 nm. The band gap (Eg) values of the films deposited by CBD and US-CBD are 3.50 and 3.67 eV, respectively.

  1. Effects of Buffer Salt Concentration on the Dominated Deposition Mechanism and Optical Characteristics of Chemically Deposited Cadmium Sulfide Thin Films

    NASA Astrophysics Data System (ADS)

    Kakhaki, Z. Makhdoumi; Youzbashi, A.; Sangpour, P.; Kazemzadeh, A.; Naderi, N.; Bazargan, A. M.

    2016-02-01

    Effects of buffer salt concentration on the rate of deposition, dominated deposition mechanism and subsequently the structural, morphological, and optical properties of cadmium sulfide (CdS) thin films deposited by chemical bath deposition (CBD) on glass substrate were investigated. The precursors were chosen to be cadmium chloride (CdCl2) as the cadmium source, thiourea (CS(NH2)2) as the sulfur source, ammonium nitrate (NH4NO3) as the buffer salt and ammonia as the complexing agent and the pH controller. The influence of the NH4NO3 concentration on the structure, morphology, film uniformity, stoichiometry and optical properties of CdS thin films was also studied by X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM), energy dispersive X-ray (EDX) spectroscope, uv-visible and photoluminescence (PL) spectroscopes. The XRD studies revealed that all the deposited films exhibited a (002)h/(111)c preferred orientation. The crystallite size was increased from 20nm to 30nm by the increase of concentration of NH4NO3 from 0.5M to 2.5M. The morphology of CdS thin films were agglomerated spherical particles consisted of smaller particles. The surface of thin films deposited at the NH4NO3 concentration of 0.5M was compact and smooth. The increase of the concentration of NH4NO3 decreased the packing density of the films. The optical band gap was in the range of 2.25-2.4eV, which was decreased by the decrement of packing density. The PL spectra showed two peaks centered at 400nm and 500nm which are attributed to violet and band-to-band emissions, respectively.

  2. Magnetism of Amorphous and Nano-Crystallized Dc-Sputter-Deposited MgO Thin Films

    PubMed Central

    Mahadeva, Sreekanth K.; Fan, Jincheng; Biswas, Anis; Sreelatha, K.S.; Belova, Lyubov; Rao, K.V.

    2013-01-01

    We report a systematic study of room-temperature ferromagnetism (RTFM) in pristine MgO thin films in their amorphous and nano-crystalline states. The as deposited dc-sputtered films of pristine MgO on Si substrates using a metallic Mg target in an O2 containing working gas atmosphere of (N2 + O2) are found to be X-ray amorphous. All these films obtained with oxygen partial pressure (PO2) ~10% to 80% while maintaining the same total pressure of the working gas are found to be ferromagnetic at room temperature. The room temperature saturation magnetization (MS) value of 2.68 emu/cm3 obtained for the MgO film deposited in PO2 of 10% increases to 9.62 emu/cm3 for film deposited at PO2 of 40%. However, the MS values decrease steadily for further increase of oxygen partial pressure during deposition. On thermal annealing at temperatures in the range 600 to 800 °C, the films become nanocrystalline and as the crystallite size grows with longer annealing times and higher temperature, MS decreases. Our study clearly points out that it is possible to tailor the magnetic properties of thin films of MgO. The room temperature ferromagnetism in MgO films is attributed to the presence of Mg cation vacancies.

  3. The impact of thickness and thermal annealing on refractive index for aluminum oxide thin films deposited by atomic layer deposition.

    PubMed

    Wang, Zi-Yi; Zhang, Rong-Jun; Lu, Hong-Liang; Chen, Xin; Sun, Yan; Zhang, Yun; Wei, Yan-Feng; Xu, Ji-Ping; Wang, Song-You; Zheng, Yu-Xiang; Chen, Liang-Yao

    2015-01-01

    The aluminum oxide (Al2O3) thin films with various thicknesses under 50 nm were deposited by atomic layer deposition (ALD) on silicon substrate. The surface topography investigated by atomic force microscopy (AFM) revealed that the samples were smooth and crack-free. The ellipsometric spectra of Al2O3 thin films were measured and analyzed before and after annealing in nitrogen condition in the wavelength range from 250 to 1,000 nm, respectively. The refractive index of Al2O3 thin films was described by Cauchy model and the ellipsometric spectra data were fitted to a five-medium model consisting of Si substrate/SiO2 layer/Al2O3 layer/surface roughness/air ambient structure. It is found that the refractive index of Al2O3 thin films decrease with increasing film thickness and the changing trend revised after annealing. The phenomenon is believed to arise from the mechanical stress in ALD-Al2O3 thin films. A thickness transition is also found by transmission electron microscopy (TEM) and SE after 900°C annealing.

  4. Adhesion analysis for chromium nitride thin films deposited by reactive magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Rusu, F. M.; Merie, V. V.; Pintea, I. M.; Molea, A.

    2016-08-01

    The thin film industry is continuously growing due to the wide range of applications that require the fabrication of advanced components such as sensors, biological implants, micro-electromechanical devices, optical coatings and so on. The selection regarding the deposition materials, as well as the deposition technology influences the properties of the material and determines the suitability of devices for certain real-world applications. This paper is focused on the adhesion force for several chromium nitride thin films obtained by reactive magnetron sputtering. All chromium nitride thin films were deposited on a silicon substrate, the discharge current and the argon flow being kept constant. The main purpose of the paper is to determine the influence of deposition parameters on the adhesion force. Therefore some of the deposition parameters were varied in order to study their effect on the adhesion force. Experimentally, the values of the adhesion force were determined in multiple points for each sample using the spectroscopy in point mode of the atomic force microscope. The obtained values were used to estimate the surface energy of the CrN thin films based on two existing mathematical models for the adhesion force when considering the contact between two bodies.

  5. Effects of Post-Deposition Annealing on the Properties of Calcium Manganese Oxide Thin Films

    NASA Astrophysics Data System (ADS)

    Ferrone, Natalie; Chaudhry, Adeel; Hart, Cacie; Lawson, Bridget; Houston, David; Neubauer, Samuel; Johnson, Anthony; Schaefer, David; Kolagani, Rajeswari

    We will present our results on the effects of post-deposition annealing on the structural and electrical properties of CaMnO3-d thin films grown by Pulsed Laser deposition. The thin films are epitaxially grown on (100) LaAlO3 which has larger in-plane lattice parameters than that of bulk CaMnO3, which leads to bi-axial tensile strain in the thin films. Results from our laboratory show that bi-axial tensile strain leads to low resistivity in thinner films, the resistivity increasing with increasing thickness. These results are suggestive of a coupling between strain and oxygen stoichiometry in the thin films. We have investigated the effects of post-deposition annealing in various gas ambients towards the goal of understanding the effects of relaxation and oxygen stoichiometric changes. We will present a comparison of the structural and electrical properties of as-grown and post-annealed films over a range of thicknesses. Support from Towson University Office of Undergraduate Research, Fisher Endowment Grant & Undergraduate Research Grant from the Fisher College of Science & Mathematics, Seed Funding Grant from the School of Emerging technologies, & NSF Grant ECCS 112856.

  6. Thin film growth rate effects for primary ion beam deposited diamondlike carbon films

    NASA Technical Reports Server (NTRS)

    Nir, D.; Mirtich, M.

    1986-01-01

    Diamondlike carbon (DLC) films were grown by primary ion beam deposition and the growth rates were measured for various beam energies, types of hydrocarbon gases and their ratio to Ar, and substrate materials. The growth rate had a linear dependence upon hydrocarbon content in the discharge chamber, and only small dependence on other parameters. For given deposition conditions a threshold in the atomic ratio of carbon to argon gas was identified below which films did not grow on fused silica substrate, but grew on Si substrate and on existing DLC films. Ion source deposition parameters and substrate material were found to affect the deposition threshold and film growth rates.

  7. Comparison of the properties of Pb thin films deposited on Nb substrate using thermal evaporation and pulsed laser deposition techniques

    NASA Astrophysics Data System (ADS)

    Perrone, A.; Gontad, F.; Lorusso, A.; Di Giulio, M.; Broitman, E.; Ferrario, M.

    2013-11-01

    Pb thin films were prepared at room temperature and in high vacuum by thermal evaporation and pulsed laser deposition techniques. Films deposited by both the techniques were investigated by scanning electron microscopy to determine their surface topology. The structure of the films was studied by X-ray diffraction in θ-2θ geometry. The photoelectron performances in terms of quantum efficiency were deduced by a high vacuum photodiode cell before and after laser cleaning procedures. Relatively high quantum efficiency (>10-5) was obtained for all the deposited films, comparable to that of corresponding bulk. Finally, film to substrate adhesion was also evaluated using the Daimler-Benz Rockwell-C adhesion test method. Weak and strong points of these two competitive techniques are illustrated and discussed.

  8. High-quality in situ manganite thin films by pulsed laser deposition at low background pressures

    NASA Astrophysics Data System (ADS)

    Tebano, A.; Balestrino, G.; Boggio, N. G.; Aruta, C.; Davidson, B.; Medaglia, P. G.

    2006-06-01

    We show that by decreasing the laser fluence it is possible to improve the oxidation process in manganite thin films under low background oxygen pressure, allowing the in situ use of conventional Reflection High Energy Electron Diffraction diagnostic. Films deposited at low fluence (corresponding to a deposition rate per pulse lower than 10-2 unit cells per laser shot) show a two-dimensional growth mode and possess very good transport properties without the necessity of any further post-growth annealing treatment. A physical model, based on the plume-background interaction as a primary mechanism of film oxidation during growth, is proposed to explain the experimental findings.

  9. Vacuum arc deposition of carbon thin films in a low pressure of hydrogen

    SciTech Connect

    de Azevedo, M.D.; Meunier, J.L. )

    1991-10-01

    In this paper results on the vacuum arch deposition (VAD) of thin carbon films on silicon, tungsten, and nickel are presented for different hydrogen pressures in the arc chamber. Raman and Auger electron spectroscopy and SEM analysis show that a large variety of film structures can be obtained. Highly oriented pyrolytic graphite is formed at high hydrogen pressure and low substrate temperature. Vacuum deposition resulted in diamond like structure. Evidence of the presence of multicrystalline spheres of diamond in some films is also presented.

  10. Metal-organic chemical vapour deposition of polycrystalline tetragonal indium sulphide (InS) thin films

    NASA Technical Reports Server (NTRS)

    Macinnes, Andrew N.; Cleaver, William M.; Barron, Andrew R.; Power, Michael B.; Hepp, Aloysius F.

    1992-01-01

    The dimeric indium thiolate /(t Bu)2In(mu-S sup t Bu)/2 has been used as a single-source precursor for the MOCVD of InS thin films. The dimeric In2S2 core is proposed to account for the formation of the nonequilibrium high-pressure tetragonal phase in the deposited films. Analysis of the deposited films has been obtained by TEM, with associated energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy.

  11. Metal-organic chemical vapour deposition of polycrystalline tetragonal indium sulphide (InS) thin films

    NASA Technical Reports Server (NTRS)

    Macinnes, Andrew N.; Cleaver, William M.; Barron, Andrew R.; Power, Michael B.; Hepp, Aloysius F.

    1992-01-01

    The dimeric indium thiolate /(t Bu)2In(mu-S sup t Bu)/2 has been used as a single-source precursor for the MOCVD of InS thin films. The dimeric In2S2 core is proposed to account for the formation of the nonequilibrium high-pressure tetragonal phase in the deposited films. Analysis of the deposited films has been obtained by TEM, with associated energy-dispersive X-ray analysis and X-ray photoelectron spectroscopy.

  12. A novel electron beam evaporation technique for the deposition of superconducting thin films

    NASA Astrophysics Data System (ADS)

    Krishna, M. G.; Muralidhar, G. K.; Rao, K. N.; Rao, G. M.; Mohan, S.

    1991-05-01

    Superconducting thin films of BiSrCaCuO have been deposited using a novel electron beam evaporation technique. In this technique the crucible has a groove around its circumference and rotates continuously during deposition. The source material is loaded in the form of pellets of the composite. Both oxides as well as flourides have been used in the starting material and a comparison of the film properties has been made. The best film was obtained on a MgO(100) substrate with a Tc onset at 85 K and Tc zero at 77 K using calcium flouride in the source material.

  13. Aligned carbon nanotube, graphene and graphite oxide thin films via substrate-directed rapid interfacial deposition.

    PubMed

    D'Arcy, Julio M; Tran, Henry D; Stieg, Adam Z; Gimzewski, James K; Kaner, Richard B

    2012-05-21

    A procedure for depositing thin films of carbon nanostructures is described that overcomes the limitations typically associated with solution based methods. Transparent and conductively continuous carbon coatings can be grown on virtually any type of substrate within seconds. Interfacial surface tension gradients result in directional fluid flow and film spreading at the water/oil interface. Transparent films of carbon nanostructures are produced including aligned ropes of single-walled carbon nanotubes and assemblies of single sheets of chemically converted graphene and graphite oxide. Process scale-up, layer-by-layer deposition, and a simple method for coating non-activated hydrophobic surfaces are demonstrated.

  14. Multi-beam pulsed laser deposition for advanced thin-film optical waveguides

    NASA Astrophysics Data System (ADS)

    Eason, R. W.; May-Smith, T. C.; Sloyan, K. A.; Gazia, R.; Darby, M. S. B.; Sposito, A.; Parsonage, T. L.

    2014-01-01

    We discuss our progress in the use of multiple laser beams and multiple targets for the pulsed laser deposition of thin films for waveguide laser and magneto-optic applications. In contrast to the more widely used single-beam/single-target geometries, having more than one laser-produced plume can allow tuning of the material properties and complex engineering of the deposited thin films. For optical applications—the majority of the work reported here—dopants can be selectively introduced, lattice mismatch and residual strain can be compensated, which is an important factor for successful growth of thin films of ∼ tens of microns thickness, and refractive index values can be adjusted for fabrication of sophisticated waveguiding structures. We discuss mixed, layered, superlattice and Bragg reflector growth, which involve out-of-plane engineering of the film structure, and in-plane engineered geometries for designs relevant to thin-film disc lasing devices. Finally we briefly discuss our most recent use of multi-plume growth for magneto-optic thin films, which involves compositional tuning of final magnetic properties.

  15. Structural and chemical composition studies of pulsed laser deposited beta-Al-Mg thin films.

    PubMed

    Radziszewska, A

    2010-03-01

    In this work, scanning electron microscopy and transmission electron microscopy and also an energy-dispersive X-ray spectroscopy were used to examine the morphology, structure and chemical composition of the beta-Al(3)Mg(2) thin films. The beta-Al-Mg thin films were produced by pulsed laser deposition. For the laser fluence (q) of 1.6 J/cm(2) the amorphous structure was observed while for the higher fluence (13.8 J/cm(2)) nanocrystalline grains were visible. The micrometer-sized droplets were also observed in the films deposited at higher laser fluence. It was found that the thickness of beta-Al-Mg films was equal to 95 nm and 260 nm for laser fluence of 1.6 J/cm(2) and 13.8 J/cm(2), respectively. Energy-dispersive X-ray spectroscopy of thin films revealed that those that were deposited at 1.6 J/cm(2) were characterized by the congruent transfer of the composition of the target to the substrate (Si). However, the contents of aluminium and magnesium varied on the cross-section of films deposited at fluence of 13.8 J/cm(2).

  16. Impact of sputter deposition parameters on molybdenum nitride thin film properties

    NASA Astrophysics Data System (ADS)

    Stöber, L.; Konrath, J. P.; Krivec, S.; Patocka, F.; Schwarz, S.; Bittner, A.; Schneider, M.; Schmid, U.

    2015-07-01

    Molybdenum and molybdenum nitride thin films are presented, which are deposited by reactive dc magnetron sputtering. The influence of deposition parameters, especially the amount of nitrogen during film synthesization, to mechanical and electrical properties is investigated. The crystallographic phase and lattice constants are determined by x-ray diffraction analyses. Further information on the microstructure as well as on the biaxial film stress are gained from techniques such as transmission electron microscopy, scanning electron microscopy and the wafer bow. Furthermore, the film resistivity and the temperature coefficient of resistance are measured by the van der Pauw technique starting from room temperature up to 300 °C. Independent of the investigated physical quantity, a dominant dependence on the sputtering gas nitrogen content is observed compared to other deposition parameters such as the plasma power or the sputtering gas pressure in the deposition chamber.

  17. Transparent ferrimagnetic semiconducting CuCr2O4 thin films by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Tripathi, T. S.; Yadav, C. S.; Karppinen, M.

    2016-04-01

    We report the magnetic and optical properties of CuCr2O4 thin films fabricated by atomic layer deposition (ALD) from Cu(thd)2, Cr(acac)3, and ozone; we deposit 200 nm thick films and anneal them at 700 °C in oxygen atmosphere to crystallize the spinel phase. A ferrimagnetic transition at 140 K and a direct bandgap of 1.36 eV are determined for the films from magnetic and UV-vis spectrophotometric measurements. Electrical transport measurements confirm the p-type semiconducting behavior of the films. As the ALD technique allows the deposition of conformal pin-hole-free coatings on complex 3D surfaces, our CuCr2O4 films are interesting material candidates for various frontier applications.

  18. Sensor activity in pulsed laser deposited and ion implanted tin oxide thin films

    NASA Astrophysics Data System (ADS)

    Lal, Ram; Grover, Rajni; Vispute, R. D.; Viswanathan, R.; Godbole, V. P.; Ogale, S. B.

    In this report we report the effect of microstructural variations on sensing activity of SnO2 thin films. The tin oxide thin films are deposited by using the technique of pulsed laser ablation. The process parameters, i.e. oxygen partial pressure, are varied to obtain films with different stoichiometries and microstructures. Some of these films are bombarded with medium energy (140 keV) argon ions at various dose levels. Structural and compositional variations in the films have been studied by using low angle X-ray diffraction, Moessbauer spectroscopy and in-situ resistivity measurements while optical response has been monitored by using UV-visible spectroscopy. The films synthesized and processed under different conditions have been subjected to examination of gas and humidity sensing behavior.

  19. Nanocluster deposition for oxide thin film growth at near room temperature

    NASA Astrophysics Data System (ADS)

    Jeon, Sang-Yong; Seong, Nak-Jin; Ahn, Jun-Ku; Lee, Hyun-Woo; Yoon, Soon-Gil

    2008-10-01

    Metal-organic chemical vapor deposition (MOCVD) at near room temperature would not only enable integration of oxide films on polymers but would provide the capability of conformal coating of high-aspect ratio features required for fabrication of many micro-and nanoelectronic devices. The concept of near room temperature MOCVD (nanocluster deposition: NCD) consists of the production of a single phase with nanosized crystalline nuclei by a chemical vapor reaction at the showerhead maintained above the decomposition temperature of the precursors and consequently deposition of the nanosized crystalline films on unheated substrates. Deposition of the nanosized crystalline nuclei on unheated substrates was performed by controlling both the showerhead temperature and the working pressure. The Bi3NbO7 (BNO) films deposited without substrate heating (real temperature of substrate surface: 50 °C) exhibit a crystalline single phase with smooth and dense morphologies, a dielectric constant of 30, a leakage current density of ~10-6 A cm-2 at 0.3 MV cm-1 and a step coverage of approximately 93% for films deposited at 100 °C on high-aspect ratio features. An NCD provides a new platform for near room temperature deposition of oxide thin films, opening the way for film deposition on polymer substrates to enable a flexible electronic device technology.

  20. Structural and optical properties of tin selenide thin films prepared by chemical bath deposition method

    NASA Astrophysics Data System (ADS)

    Solanki, V. R.; Parmar, R. J.; Pathak, R. J.; Parmar, M. D.

    2017-05-01

    Tin selenide (SnSe) is an important IV-VI semiconductor used for various devices like memory switching, photoelectrical cells, holographic recording systems. Chemical bath deposition technique has been used to synthesize tin selenide (SnSe) thin films. The SnSe thin films are deposited on glass substrates in an aqueous alkaline medium using sodium selenosulphate as Se-2 ion source and Tin Chloride as Sn+2 ion source. The SnSe Thin films were characterized to study the structural properties. XRD study confirms the formation of orthorhombic structural. The Prepared samples were investigated for optical characterization by UV-VIS Spectroscopy. The optical band gap was found to be direct, that is equal to 1.73eV.

  1. Epitaxial thin film deposition of magnetostrictive materials and its effect on magnetic anisotropy

    NASA Astrophysics Data System (ADS)

    McClure, Adam Marc

    Magnetostriction means that the dimensions of a material depend on its magnetization. The primary goal of this dissertation was to understand the effect of magnetostriction on the magnetic anisotropy of single crystal magnetostrictive thin films, where the epitaxial pinning of the material to a substrate could inhibit its conversion to new dimensions. In order to address this goal, several Fe-based binary alloys were deposited onto various substrates by molecular beam epitaxy. The samples were characterized by an array of techniques including electron diffraction, Rutherford backscattering, vibrating sample magnetometry, ferromagnetic resonance, and x-ray absorption spectroscopies. The attempted growths of crystalline magnetostrictive thin films resulted in successful depositions of Fe1-xGax and Fe1-x Znx. Depositions onto MgO(001) substrates result in an in-plane cubic magnetic anisotropy, as expected from the cubic symmetry of the Fe-based thin films, and a strong out-of-plane uniaxial anisotropy that forces the magnetization to lie in the plane of the films. Depositions onto ZnSe/GaAs(001) substrates feature an additional in-plane uniaxial anisotropy. The magnitudes and signs of the in-plane anisotropies depend on the Ga content. Furthermore, the cubic anisotropy constant of Fe1-xGax samples deposited onto MgO substrates switches sign at a lower Ga concentration than is seen in bulk Fe1-xGax. The effect on the magnetic anisotropy of depositing a magnetostrictive material as an epitaxial thin film is influenced by the material's magnetostrictive properties and the substrate upon which it is deposited. In particular, pinning a magnetoelastic material to a substrate will modify its cubic anisotropy, and depositions on substrates compliant to an anisotropic strain relaxation may result in a strong in-plane uniaxial anisotropy.

  2. Chemical bath deposition of thin film cadmium selenide for photoelectrochemical cells

    SciTech Connect

    Boudreau, R.A.; Raugh, R.D.

    1983-02-01

    Chemical bath deposition provides an attractive, low cost method of producing cadmium chalcogenide thin films. Intimate contact between the bath solution and the substrate material permits uniform deposition on substrates of complex geometry, presently difficult with spray pyrolysis, vacuum evaporation, or electrodeposition techniques. For CdSe, rigorous control of deposition conditions promotes the formation of a hexagonal, specularly reflecting deposit rather than a less desirable sphalerite (cubic) powdery deposit. Scanning electron microscopy reveals a small grained layered plate morphology similar to that produced by the evaporation method. Specularly reflecting CdSe films can be formed over large area substrates at a thickness optimal for their use as photoelectrochemical cells (PEC). Employing polysulfide as the redox couple, conversion efficiencies as high as 6.8% have been achieved in the authors' laboratory for these films using a tungstenhalogen white light source.

  3. Drop-photochemical deposition of aluminum oxide thin films from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Sato, Shunta; Ichimura, Masaya

    2017-04-01

    Aluminum oxide thin films were deposited onto fluorine-doped tin oxide-coated glass by drop photochemical deposition for the first time. The deposition solution was deionized water containing aluminum sulfate and sodium thiosulfate. Small amount of the solution was dropped on the substrate and irradiated with UV light. The solution was replaced with new one after 5 min irradiation, and the process was repeated 10 times. A film was not deposited without thiosulfate ions in the solution. The deposited films were transparent, and their band gap was larger than 4 eV. The O/Al composition ratio was about 1.2, smaller than the stoichiometric ratio 1.5.

  4. Plasma and Laser-Enhanced Deposition of Powders and Thin Films.

    NASA Astrophysics Data System (ADS)

    David, Moses

    The objective of this thesis has been the development of novel plasma and laser based techniques for the deposition and characterization of thin films and nano-scale powders. The different energy sources utilized for excitation and break -down of reactive species prior to deposition include an RF plasma discharge, an excimer laser and a CO _2 laser. Nanometer-scale (10-20 nm) powders and thin films of aluminum nitride (AlN) have been successfully deposited in a glow discharge by reacting trimethylaluminum and ammonia. Macroquantities (~800 mg/hr) of powder have been collected at the centers of two vortices around which the reactant gases swirl. Powders of AlN have large surface areas (85 m^2/g) and are free from oxygen contamination. Diamond-like-carbon (DLC) films have been deposited from ternary mixtures of butadiene, argon and hydrogen. DLC films have been etched in O _2 and CF_4/O _2 plasmas. The etching behavior was correlated with the deposition feed gas composition by combining the etch rate, bias voltage during deposition and the deposition rate into a new non-dimensional number. Two new processes for depositing copper films have been developed. The first technique involves the hydrogen plasma reduction of copper formate films and the second technique involves the reactive excimer laser ablation of copper formate. Particle forming plasmas have been characterized by measuring the light scattering intensity during the deposition of silicon nitride from silane/ammonia plasmas. Both spatial variations and transients during the plasma start -up and shut-off steps have been measured. The ultraviolet (vacuum ultraviolet and extreme ultraviolet) reflectance characteristics of AlN, DLC and SiC thin films has been measured. AlN and SiC films exhibit a relatively high (~20-40%) reflectance in the different regions of the ultraviolet spectrum. An improved algorithm has been developed for estimating thin film parameters such as thickness, refractive index, band-gap, and

  5. Chemical vapour deposition of thermochromic vanadium dioxide thin films for energy efficient glazing

    SciTech Connect

    Warwick, Michael E.A.; Binions, Russell

    2014-06-01

    Vanadium dioxide is a thermochromic material that undergoes a semiconductor to metal transitions at a critical temperature of 68 °C. This phase change from a low temperature monoclinic structure to a higher temperature rutile structure is accompanied by a marked change in infrared reflectivity and change in resistivity. This ability to have a temperature-modulated film that can limit solar heat gain makes vanadium dioxide an ideal candidate for thermochromic energy efficient glazing. In this review we detail the current challenges to such glazing becoming a commercial reality and describe the key chemical vapour deposition technologies being employed in the latest research. - Graphical abstract: Schematic demonstration of the effect of thermochromic glazing on solar radiation (red arrow represents IR radiation, black arrow represents all other solar radiation). - Highlights: • Vanadium dioxide thin films for energy efficient glazing. • Reviews chemical vapour deposition techniques. • Latest results for thin film deposition for vanadium dioxide.

  6. Characterization of ethylcellulose and hydroxypropyl methylcellulose thin films deposited by matrix-assisted pulsed laser evaporation

    NASA Astrophysics Data System (ADS)

    Palla-Papavlu, A.; Rusen, L.; Dinca, V.; Filipescu, M.; Lippert, T.; Dinescu, M.

    2014-05-01

    In this study is reported the deposition of hydroxypropyl methylcellulose (HPMC) and ethylcellulose (EC) by matrix-assisted pulsed laser evaporation (MAPLE). Both HPMC and EC were deposited on silicon substrates using a Nd:YAG laser (266 nm, 5 ns laser pulse and 10 Hz repetition rate) and then characterized by atomic force microscopy and Fourier transform infrared spectroscopy. It was found that for laser fluences up to 450 mJ/cm2 the structure of the deposited HPMC and EC polymer in the thin film resembles to the bulk. Morphological investigations reveal island features on the surface of the EC thin films, and pores onto the HPMC polymer films. The obtained results indicate that MAPLE may be an alternative technique for the fabrication of new systems with desired drug release profile.

  7. Pulsed laser deposition of tungsten carbide thin films on silicon (100) substrate

    NASA Astrophysics Data System (ADS)

    Suda, Y.; Nakazono, T.; Ebihara, K.; Baba, K.

    1997-01-01

    A method of synthesizing tungsten carbide (WC) thin films by a pulsed YAG laser deposition is investigated. WC thin films are deposited on silicon (100) substrates by using WC5%Co alloy targets. Glancing angle X-ray diffraction shows that the strong peaks of W 2C appear at the substrate temperature of 500°C. Beside the strong peaks of W 2C, weak peaks of WC and W 3Co 3C appear at the substrate temperature of 650°C. Auger electron spectroscopy shows that the almost stoichiometric WC films are deposited at the methane gas pressure of 1.0 Pa. Morphological features of the samples have been obtained by employing the technique of scanning electron microscopy. X-ray photoelectron spectroscopy has been used to obtain structural and compositional information about the samples.

  8. Investigation on single walled carbon nanotube thin films deposited by Langmuir Blodgett method

    SciTech Connect

    Vishalli, Dharamvir, Keya; Kaur, Ramneek; Raina, K. K.

    2015-05-15

    Langmuir Blodgett is a technique to deposit a homogeneous film with a fine control over thickness and molecular organization. Thin films of functionalized SWCNTs have been prepared by Langmuir Blodgett method. The good surface spreading properties of SWCNTs at air/water interface are indicated by surface pressure-area isotherm and the monolayer formed on water surface is transferred onto the quartz substrate by vertical dipping. A multilayer film is thus obtained in a layer by layer manner. The film is characterized by Atomic Force Microscope (AFM), UV-Vis-NIR spectroscopy and FTIR.AFM shows the surface morphology of the deposited film. UV-Vis-NIR spectroscopy shows the characteristic peaks of semiconducting SWCNTs. The uniformity of LB film can be used further in understanding the optical and electrical behavior of these materials.

  9. Vacancies ordered in screw form (VOSF) and layered indium selenide thin film deposition by laser back ablation

    NASA Astrophysics Data System (ADS)

    Beck, Kenneth M.; Wiley, William R.; Venkatasubramanian, Eswaranand; Ohuchi, Fumio

    2009-09-01

    Indium selenide thin films are important due to their applications in non-volatile memory and solar cells. In this work, we present an initial study of a new application of deposition-site selective laser back ablation (LBA) for making thin films of In 2Se 3. Invacuo annealing and subsequent characterization of the films by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) indicate that control of substrate temperature during deposition and post-deposition annealing temperature is critical in determining the phase and composition of the films. The initial laser fluence and target film thickness determine the amount of material deposited onto the substrate.

  10. Vacancies Ordered in Screw Form (VOSF) and Layered Indium Selenide Thin Film Deposition by Laser Back Ablation

    SciTech Connect

    Beck, Kenneth M.; Wiley, William R.; Venkatasubramanian, Eswaranand; Ohuchi, Fumio S.

    2009-09-30

    Indium selenide thin films are important due to their applications in non-volatile memory and solar cells. In this work, we present an initial study of a new application of deposition-site selective laser back ablation (LBA) for making thin films of In2Se3. In-vacuo annealing and subsequent characterization of the films by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) indicate that control of substrate temperature during deposition and post-deposition annealing temperature is critical in determining the phase and composition of the films. The initial laser fluence and target film thickness determine the amount of material deposited onto the substrate.

  11. Embedded argon as a tool for sampling local structure in thin plasma deposited aluminum oxide films

    SciTech Connect

    Prenzel, Marina; Kortmann, Annika; Keudell, Achim von; Arcos, Teresa de los; Winter, Joerg

    2012-11-15

    Al{sub 2}O{sub 3} thin films, either amorphous or of varying degrees of crystallinity, were deposited by two-frequency radio-frequency magnetron sputtering. Film crystallinity was investigated by Fourier transform infrared spectroscopy and X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) was employed to determine the amount of Ar naturally trapped within the films during the deposition process. A clear correlation was found between the existence of crystalline phases, as determined by XRD, and a shift towards lower binding energy positions of the Ar2p core levels of embedded gas. The shift is due to differences in the local Al{sub 2}O{sub 3} matrix (amorphous or crystalline) of the embedded gas, thus, providing an XPS fingerprint that can be used to qualitatively determine the presence or absence of crystalline phases in very thin films.

  12. Bath Parameter Dependence of Chemically-Deposited Copper Selenide Thin Film

    NASA Astrophysics Data System (ADS)

    Al-Mamun; Islam, A. B. M. O.

    In this article, a low cost chemical bath deposition (CBD) technique has been used for the preparation of Cu2-xSe thin films on to glass substrate. Different thin films (0.2-0.6 μm) were prepared by adjusting the bath parameter like concentration of ammonia, deposition time, temperature of the solution, and the ratios of the mixing composition between copper and selenium in the reaction bath. From these studies, it reveals that at low concentration of ammonia or TEA, the terminal thicknesses of the films are less, which gradually increases with the increase of concentrations and then drop down at still higher concentrations. It has been found that complexing the Cu2+ ions with TEA first, and then addition of ammonia yields better results than the reverse process. The film thickness increases with the decrease of value x of Cu2-xSe.

  13. Evaluation of the smallest protein units in a thin film deposited by IR laser

    NASA Astrophysics Data System (ADS)

    Nakayama, S.; Senna, M.

    2007-04-01

    Silk fibroin (SF) thin films were prepared by pulsed IR laser deposition. Size variation of the smallest protein units (SPU) in the films were evaluated by atomic force microscopy. Average SPU size doubled with increasing the background gas pressure by an order of magnitude. The size of SPU was significantly larger when the film was deposited in Ar atmosphere than in He while the pressure was kept constant at 100Pa. We discussed about the growth of SPU in terms of ionization as a consequence of hydrogen bond rupture by laser irradiation, with the aid of infrared spectra. Effects of the background gas were suspected primarily to be the difference in the states of collision with the fragmented protein units immediately after the laser bombardment of the target, within or near the plume zone. The results suggest the possibility of controlling the nano-structures of the protein thin film by optimizing the background gas condition.

  14. Synthesis and Characterization of Molybdenum Doped ZnO Thin Films by SILAR Deposition Method

    NASA Astrophysics Data System (ADS)

    Radha, R.; Sakthivelu, A.; Pradhabhan, D.

    2016-08-01

    Molybdenum (Mo) doped zinc oxide (ZnO) thin films were deposited on the glass substrate by Successive Ionic Layer Adsorption and Reaction (SILAR) deposition method. The effect of Mo dopant concentration of 5, 6.6 and 10 mol% on the structural, morphological, optical and electrical properties of n-type Mo doped ZnO films was studied. The X-ray diffraction (XRD) results confirmed that the Mo doped ZnO thin films were polycrystalline with wurtzite structure. The field emission scanning electron microscopy (FESEM) studies shows that the surface morphology of the films changes with Mo doping. A blue shift of the optical band gap was observed in the optical studies. Effect of Mo dopant concentration on electrical conductivity was studied and it shows comparatively high electrical conductivity at 10 mol% of Mo doping concentration.

  15. Pulsed laser deposition and characterization of conductive RuO{sub 2} thin films

    SciTech Connect

    Iembo, A.; Fuso, F.; Arimondo, E.; Ciofi, C.; Pennelli, G.; Curro, G.M.; Neri, F.; Allegrini, M. |

    1997-06-01

    RuO{sub 2} thin films have been produced on silicon-based substrates by {ital in situ} pulsed laser deposition for the first time. The electrical properties, the surface characteristics, the crystalline structure, and the film-substrate interface of deposited samples have been investigated by 4-probe resistance versus temperature technique, scanning electron microscopy, x-ray photoelectron spectroscopy, x-ray diffraction, and transmission electron microscopy, respectively. The films show good electrical properties. The RuO{sub 2}-substrate interface is very thin ({approx}3 nm), since not degraded by any annealing process. These two characteristics render our films suitable to be used as electrodes in PZT-based capacitors.{copyright} {ital 1997 Materials Research Society.}

  16. Chalcogenide-based thin film sensors prepared by pulsed laser deposition technique

    NASA Astrophysics Data System (ADS)

    Schubert, J.; Schöning, M. J.; Schmidt, C.; Siegert, M.; Mesters, St.; Zander, W.; Kordos, P.; Lüth, H.; Legin, A.; Mourzina, Yu. G.; Seleznev, B.; Vlasov, Yu. G.

    One advantage of the pulsed laser deposition (PLD) method is the stoichiometric transfer of multi-component target material to a given substrate. This advantage of the PLD determined the choice to prepare chalco-genide-based thin films with an off-axis geometry PLD. Ag-As-S and Cu-Ag-As-Se-Tetargets were used to deposit thin films on Si substrates for an application as a heavy metal sensing device. The films were characterized by means of Rutherford backscattering spectrometry (RBS), transmission electron microscopy (TEM), and electrochemical measurements. The same stoichiometry of the films and the targets was confirmed by RBS measurements. We observed a good long-term stability of more than 60 days and a nearly Nernstian sensitivity towards Pb and Cu, which is comparable to bulk sensors.

  17. Critical issues in plasma deposition of microcrystalline silicon for thin film transistors

    NASA Astrophysics Data System (ADS)

    Roca i Cabarrocas, Pere; Djeridane, Yassine; Bui, V. D.; Bonnassieux, Yvan; Abramov, Alexey

    2008-03-01

    After more than 20 years of research and despite improved transport properties with respect to amorphous silicon, microcrystalline silicon thin film transistors (TFTs) are not yet ready for industrial production. We review here the progress made in the understanding of the growth of this material with particular emphasis on industry relevant aspects such as deposition rate and uniformity. We show that the synthesis of silicon nanocrystals in the plasma offers unique advantages with respect to deposition rate and film properties. In particular, this allows the production of films which are similar to polycrystalline thin films produced by furnace and laser crystallization. The growth process is also discussed with respect to TFT design: top gate or bottom gate. Results on bottom gate TFTs meeting all the necessary requirements in terms of mobility, ON/OFF ratio and stability required for AMOLED applications are also reported.

  18. Low temperature deposition of polycrystalline silicon thin films on a flexible polymer substrate by hot wire chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Lee, Sang-hoon; Jung, Jae-soo; Lee, Sung-soo; Lee, Sung-bo; Hwang, Nong-moon

    2016-11-01

    For the applications such as flexible displays and solar cells, the direct deposition of crystalline silicon films on a flexible polymer substrate has been a great issue. Here, we investigated the direct deposition of polycrystalline silicon films on a polyimide film at the substrate temperature of 200 °C. The low temperature deposition of crystalline silicon on a flexible substrate has been successfully made based on two ideas. One is that the Si-Cl-H system has a retrograde solubility of silicon in the gas phase near the substrate temperature. The other is the new concept of non-classical crystallization, where films grow by the building block of nanoparticles formed in the gas phase during hot-wire chemical vapor deposition (HWCVD). The total amount of precipitation of silicon nanoparticles decreased with increasing HCl concentration. By adding HCl, the amount and the size of silicon nanoparticles were reduced remarkably, which is related with the low temperature deposition of silicon films of highly crystalline fraction with a very thin amorphous incubation layer. The dark conductivity of the intrinsic film prepared at the flow rate ratio of RHCl=[HCl]/[SiH4]=3.61 was 1.84×10-6 Scm-1 at room temperature. The Hall mobility of the n-type silicon film prepared at RHCl=3.61 was 5.72 cm2 V-1s-1. These electrical properties of silicon films are high enough and could be used in flexible electric devices.

  19. Effect of thickness on electrical properties of SILAR deposited SnS thin films

    NASA Astrophysics Data System (ADS)

    Akaltun, Yunus; Astam, Aykut; Cerhan, Asena; ćayir, Tuba

    2016-03-01

    Tin sulfide (SnS) thin films of different thickness were prepared on glass substrates by successive ionic layer adsorption and reaction (SILAR) method at room temperature using tin (II) chloride and sodium sulfide aqueous solutions. The thicknesses of the films were determined using spectroscopic ellipsometry measurements and found to be 47.2, 65.8, 111.0, and 128.7nm for 20, 25, 30 and 35 deposition cycles respectively. The electrical properties of the films were investigated using d.c. two-point probe method at room temperature and the results showed that the resistivity was found to decrease with increasing film thickness.

  20. Composition control of PZT thin films by varying technological parameters of RF magnetron sputter deposition

    NASA Astrophysics Data System (ADS)

    Pronin, V. P.; Dolgintsev, D. M.; Pronin, I. P.; Senkevich, S. V.; Kaptelov, E. Yu; Sergienko, A. Yu

    2017-07-01

    The article presents the effect of technological parameters of RF magnetron sputtering on the concentration of components of thin-film ferroelectric structures based on lead zirconate titanate PZT in the region of the morphotropic phase boundary. It is shown that by changing the distance from the target to the substrate and the pressure of the working gas mixture Ar + O2, it is possible to vary the composition of the deposited thin layers.

  1. Fabrication of organic-inorganic perovskite thin films for planar solar cells via pulsed laser deposition

    SciTech Connect

    Liang, Yangang; Zhang, Xiaohang; Gong, Yunhui; Shin, Jongmoon; Wachsman, Eric D.; Takeuchi, Ichiro; Yao, Yangyi; Hsu, Wei-Lun; Dagenais, Mario

    2016-01-15

    We report on fabrication of organic-inorganic perovskite thin films using a hybrid method consisting of pulsed laser deposition (PLD) of lead iodide and spin-coating of methylammonium iodide. Smooth and highly crystalline CH{sub 3}NH{sub 3}PbI{sub 3} thin films have been fabricated on silicon and glass coated substrates with fluorine doped tin oxide using this PLD-based hybrid method. Planar perovskite solar cells with an inverted structure have been successfully fabricated using the perovskite films. Because of its versatility, the PLD-based hybrid fabrication method not only provides an easy and precise control of the thickness of the perovskite thin films, but also offers a straightforward platform for studying the potential feasibility in using other metal halides and organic salts for formation of the organic-inorganic perovskite structure.

  2. Splitting methanol on ultra-thin MgO(100) films deposited on a Mo substrate.

    PubMed

    Song, Zhenjun; Xu, Hu

    2017-03-08

    The dissociation reaction of methanol on metal-supported MgO(100) films has been studied by employing density functional theory calculations. As far as we know, the dissociation of a single methanol molecule over inert oxide insulators such as MgO has not yet been successfully realized without the introduction of defects or low coordinated atoms. By depositing ultra-thin oxide films on a Mo substrate, we have successfully proposed the dissociative state of methanol. The dissociation reaction is energetically exothermic and nearly barrierless. The lattice mismatch between ultra-thin MgO(100) films and metal substrates plays a crucial role in the heterolytic dissociation of adsorbates, while the electronic effect of the Mo(100) substrate plays a non-ignorable role in the homolytic dissociation of methanol. The metal-supported ultra-thin oxide films studied herein provide a versatile approach to enhance the surface reaction activity and properties of oxides.

  3. Fabrication of organic-inorganic perovskite thin films for planar solar cells via pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Liang, Yangang; Yao, Yangyi; Zhang, Xiaohang; Hsu, Wei-Lun; Gong, Yunhui; Shin, Jongmoon; Wachsman, Eric D.; Dagenais, Mario; Takeuchi, Ichiro

    2016-01-01

    We report on fabrication of organic-inorganic perovskite thin films using a hybrid method consisting of pulsed laser deposition (PLD) of lead iodide and spin-coating of methylammonium iodide. Smooth and highly crystalline CH3NH3PbI3 thin films have been fabricated on silicon and glass coated substrates with fluorine doped tin oxide using this PLD-based hybrid method. Planar perovskite solar cells with an inverted structure have been successfully fabricated using the perovskite films. Because of its versatility, the PLD-based hybrid fabrication method not only provides an easy and precise control of the thickness of the perovskite thin films, but also offers a straightforward platform for studying the potential feasibility in using other metal halides and organic salts for formation of the organic-inorganic perovskite structure.

  4. Homogeneous, dual layer, solid state, thin film deposition for structural and/or electrochemical characteristics

    DOEpatents

    Pitts, J. Roland; Lee, Se-Hee; Tracy, C. Edwin; Li, Wenming

    2014-04-08

    Solid state, thin film, electrochemical devices (10) and methods of making the same are disclosed. An exemplary device 10 includes at least one electrode (14) and an electrolyte (16) deposited on the electrode (14). The electrolyte (16) includes at least two homogenous layers of discrete physical properties. The two homogenous layers comprise a first dense layer (15) and a second porous layer (16).

  5. Some Questions of Vacuum Technology during the Deposition of Thin Films,

    DTIC Science & Technology

    The structure and properties of thin films obtained by thermal vaporization in a vacuum are determined to a considerable degree by the conditions of condensation and depend on temperature of vaporization, rate of condensation, and angle of incidence of deposited substance on the base layer; nature of the base layer, its degree of purity, and microrelief of the

  6. Electrical conductivity and crystallization of amorphous bismuth ruthenate thin films deposited by spray pyrolysis.

    PubMed

    Ryll, Thomas; Brunner, Andreas; Ellenbroek, Stefan; Bieberle-Hutter, Anja; Rupp, Jennifer L M; Gauckler, Ludwig J

    2010-11-14

    Amorphous oxide thin films with tailored functionality will be crucial for the next generation of micro-electro-mechanical-systems (MEMS). Due to potentially favorable electronic and catalytic properties, amorphous bismuth ruthenate thin films might be applied in this regard. We report on the deposition of amorphous bismuth ruthenate thin films by spray pyrolysis, their crystallization behavior and electrical conductivity. At room temperature the 200 nm thin amorphous films exhibit a high electrical conductivity of 7.7 × 10(4) S m(-1), which was found to be slightly thermally activated (E(a) = 4.1 × 10(-3) eV). It follows that a long-range order of the RuO(6) octahedra is no precondition for the electrical conductivity of Bi(3)Ru(3)O(11). Upon heating to the temperature range between 490 °C and 580 °C the initially amorphous films crystallize rapidly. Simultaneously, a transition from a dense and continuous film to isolated Bi(3)Ru(3)O(11) particles on the substrate takes place. Solid-state agglomeration is proposed as the mechanism responsible for disintegration. The area specific resistance of Bi(3)Ru(3)O(11) particles contacted by Pt paste on gadolinia doped ceria electrolyte pellets was found to be 7 Ω cm(2) at 607 °C in air. Amorphous bismuth ruthenate thin films are proposed for application in electrochemical devices operating at low temperatures, where a high electrical conductivity is required.

  7. Pulsed laser deposition of polyhydroxybutyrate biodegradable polymer thin films using ArF excimer laser

    NASA Astrophysics Data System (ADS)

    Kecskemeti, G.; Smausz, T.; Kresz, N.; Tóth, Zs.; Hopp, B.; Chrisey, D.; Berkesi, O.

    2006-11-01

    We demonstrated the pulsed laser deposition (PLD) of high quality films of a biodegradable polymer, the polyhydroxybutyrate (PHB). Thin films of PHB were deposited on KBr substrates and fused silica plates using an ArF ( λ = 193 nm, FWHM = 30 ns) excimer laser with fluences between 0.05 and 1.5 J cm -2. FTIR spectroscopic measurements proved that at the appropriate fluence (0.05, 0.09 and 0.12 J cm -2), the films exhibited similar functional groups with no significant laser-produced modifications present. Optical microscopic images showed that the layers were contiguous with embedded micrometer-sized grains. Ellipsometric results determined the wavelength dependence ( λ ˜ 245-1000 nm) of the refractive index and absorption coefficient which were new information about the material and were not published in the scientific literature. We believe that our deposited PHB thin films would have more possible applications. For example to our supposal the thin layers would be applicable in laser induced forward transfer (LIFT) of biological materials using them as absorbing thin films.

  8. Enhanced electrical and optical properties of CdS:Na thin films by photochemical deposition

    NASA Astrophysics Data System (ADS)

    Kumar, V. Nirmal; Suriakarthick, R.; Gopalakrishnan, R.; Hayakawa, Y.

    2017-06-01

    CdS:Na thin film was deposited on a glass substrate by photochemical deposition from aqueous solution contained CdSO4.5H2O and Na2S2O3 as cation and anion sources, respectively. The anion source Na2S2O3 served as Na dopant source. The deposited film exhibited cubic phase of CdS and incorporation of Na was revealed from X-ray diffraction study. The incorporation of Na in CdS changed the surface morphology from spherical to nano rods. CdS:Na thin film showed blue shift in its absorption spectrum which was more desirable for transmitting higher energy photons (visible region) in thin film solar cells. The Raman analysis confirmed 1 LO and 2 LO process at 297 and 593 cm-1, respectively. The carrier concentration of CdS increased with the inclusion of Na and its resistivity value decreased. Both the electrical and optical properties of CdS were enhanced in CdS:Na thin films which was desirable as a window layer material for photovoltaic application.

  9. Nonlinear polarization responses of ZrO2-based thin films fabricated by chemical solution deposition

    NASA Astrophysics Data System (ADS)

    Yoneda, Shingo; Hosokura, Tadasu; Kimura, Masahiko; Ando, Akira; Shiratsuyu, Kosuke

    2017-10-01

    The nonlinear polarization responses of ZrO2-based thin films were investigated. Y, Ce, Ti, and Sn were used as substitutes in ZrO2 thin films by chemical solution deposition. A pure ZrO2 film and the ZrO2 film with 1% Y substitution showed constricted polarization–electric field (P–E) curves. In contrast, the ZrO2 film with 5% Y substitution showed a linear P–E curve. The dielectric constants of the pure ZrO2 film and the ZrO2 film with 1% Y substitution increased by 7 and 11%, respectively, under an applied electric field of 2.5 MV/cm. The nonlinearity of the polarization responses was decreased by Ce substitution and Ti substitution. The ZrO2 films with Sn substitution showed narrow P–E curves. The dielectric constant of the ZrO2 film with 10% Sn substitution increased by 13% under an applied electric field of 3 MV/cm. These dielectric constant increases originate from electric-field-induced phase transitions of ZrO2-based thin films.

  10. Impurity-doped ZnO Thin Films Prepared by Physical Deposition Methods Appropriate for Transparent Electrode Applications in Thin-film Solar Cells

    NASA Astrophysics Data System (ADS)

    Minami, Tadatsugu; Miyata, Toshihiro; Nomoto, Jun-ichi

    2012-04-01

    This paper describes the development of transparent conducting impurity-doped ZnO thin films that would be appropriate for applications as transparent electrodes in thin-film solar cells. Transparent conducting Al-, B- and Ga-doped ZnO (AZO, BZO and GZO) thin films were prepared in a thickness range from 500 to 2000 nm on glass substrates at 200°C using various physical deposition methods: BZO films with vacuum arc plasma evaporation, AZO and GZO films with different types of magnetron sputtering depositions (MSDs) and all films with pulsed laser deposition (PLD). The suitability and stability of the electrical properties and, in addition, the suitability of the light scattering characteristics and surface texture formation were investigated in the prepared thin films. In particular, the suitability and stability evaluation was focused on the use of AZO, BZO and GZO thin films prepared by doping each impurity at an appropriate content to attain the lowest resistivity. The higher Hall mobility obtained in impurity-doped ZnO thin films with a resistivity on the order of 10-4 Ωcm was related more to the content, i.e., the obtained carrier concentration, rather than the kind of impurity doped into the films. The stability of resistivity of the BZO thin films in long-term moisture-resistance tests (in air at 85% relative humidity and 85°C) was found to be lower than that of the AZO and GZO thin films. The surface texture formation was carried out by wet-chemical etching (in a 0.1% HCl solution at 25°C) conducted either before or after being heat-treated either with rapid thermal annealing (RTA) or without RTA. The suitability of the light scattering characteristics and the surface texture formation obtainable by wet-chemical etching (for use in transparent electrode applications) was considerably dependent on the deposition method used as well as whether the wet-chemical etching was conducted with or without RTA. A significant improvement of both transmittance and

  11. Electron beam physical vapor deposition of thin ruby films for remote temperature sensing

    SciTech Connect

    Li Wei; Coppens, Zachary J.; Greg Walker, D.; Valentine, Jason G.

    2013-04-28

    Thermographic phosphors (TGPs) possessing temperature-dependent photoluminescence properties have a wide range of uses in thermometry due to their remote access and large temperature sensitivity range. However, in most cases, phosphors are synthesized in powder form, which prevents their use in high resolution micro and nanoscale thermal microscopy. In the present study, we investigate the use of electron beam physical vapor deposition to fabricate thin films of chromium-doped aluminum oxide (Cr-Al{sub 2}O{sub 3}, ruby) thermographic phosphors. Although as-deposited films were amorphous and exhibited weak photoluminescence, the films regained the stoichiometry and {alpha}-Al{sub 2}O{sub 3} crystal structure of the combustion synthesized source powder after thermal annealing. As a consequence, the annealed films exhibit both strong photoluminescence and a temperature-dependent lifetime that decreases from 2.9 ms at 298 K to 2.1 ms at 370 K. Ruby films were also deposited on multiple substrates. To ensure a continuous film with smooth surface morphology and strong photoluminescence, we use a sapphire substrate, which is thermal expansion coefficient and lattice matched to the film. These thin ruby films can potentially be used as remote temperature sensors for probing the local temperatures of micro and nanoscale structures.

  12. Palladium thin film deposition from liquid precursors on polymers by projected excimer beams

    NASA Astrophysics Data System (ADS)

    Kordás, K.; Nánai, L.; Bali, K.; Stépán, K.; Vajtai, R.; George, T. F.; Leppävuori, S.

    2000-12-01

    Palladium thin films are deposited on polyimide (PI) and mylar (PET) surfaces from a solution by employing XeCl and KrF excimer lasers. The substrates are plunged in a [Pd(NH3)4]2+/HCOH system, and an illuminated diaphragm is projected onto the polymers through the precursor layer. Due to the incident laser beam, chemical reactions take place at the solution/polymer interface, yielding thin Pd films on the surface. The formation and thickness of the Pd layer depend on the numbers of pulses, laser fluence and wavelength of the laser. The formed metallic, adhesive, and homogeneous Pd deposits are found to be suitable for further electroless copper deposition. Techniques such as DEKTAK profilometry, optical microscopy, FESEM (equipped with EDX) and XRD are involved in the determination of morphological, structural and compositional characteristics of the deposited layers.

  13. Pulsed laser deposition of silk protein: Effect of photosensitized-ablation on the secondary structure in thin deposited films

    NASA Astrophysics Data System (ADS)

    Tsuboi, Yasuyuki; Goto, Masaharu; Itaya, Akira

    2001-06-01

    Silk fibroin is a simple protein expected to have functional applications in medicine and bioelectronics. The primary structure of this protein is quite simple, and the main secondary structures are β-sheet crystals and amorphous random coils. In the present study, we investigated pulsed laser deposition (PLD) of fibroin with the β-sheet structures as targets. The primary and secondary structures in films deposited were analyzed using infrared spectroscopy. Normal laser deposition at 351 nm using neat fibroin targets produced thin films of fibroin with a random coiled structure. Ablation was triggered by two-photonic excitation of the peptide chains, which resulted in the destruction of β-sheet structure in PLD. In order to avoid the two-photonic excitation, we adopted a PLD method utilizing anthracene (5-0.1 wt %) in a photosensitized reaction involving doped fibroin targets. Laser light (351 or 355 nm) was absorbed only by anthracene, which plays an important role converting photon energy to thermal energy with great ablation efficiency. Thin fibroin films deposited by this method had both random coil and β-sheet structures. As the dopant concentration and laser fluence decreased, the ratio of β-sheet domain to random coil increased in thin deposited films.

  14. Chemical bath deposition and characterization of electrochromic thin films of sodium vanadium bronzes

    SciTech Connect

    Najdoski, Metodija; Koleva, Violeta; Demiri, Sani

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer We report a new chemical bath method for the deposition of vanadium bronze thin films. Black-Right-Pointing-Pointer The films are phase mixture of NaV{sub 6}O{sub 15} and Na{sub 1.1}V{sub 3}O{sub 7.9} with 10.58% lattice water. Black-Right-Pointing-Pointer The as-deposited vanadium bronze films exhibit two-step electrochromism. Black-Right-Pointing-Pointer They change their yellow-orange color to green and then from green to blue color. Black-Right-Pointing-Pointer The method allows the preparation of films on substrates with low melting point. -- Abstract: Thin yellow-orange films of sodium vanadium oxide bronzes have been prepared from a sodium-vanadium solution (1:1) at 75 Degree-Sign C and pH = 3. The composition, structure and morphology of the films have been studied by XRD, IR spectroscopy, TG and SEM-EDX analyses. It has been established that the prepared films are a phase mixture of hydrated NaV{sub 6}O{sub 15} (predominant component) and Na{sub 1.1}V{sub 3}O{sub 7.9} with total water content of 10.58%. The sodium vanadium bronze thin films exhibit two-step electrochromism followed by color change from yellow-orange to green, and then from green to blue. The cyclic voltammetry measurements on the as-deposited and annealed vanadium bronze films reveal the existence of different oxidation/reduction vanadium sites which make these films suitable for electrochromic devices. The annealing of the films at 400 Degree-Sign C changes the composition, optical and electrochemical properties.

  15. Silicon solar cell performance deposited by diamond like carbon thin film ;Atomic oxygen effects;

    NASA Astrophysics Data System (ADS)

    Aghaei, Abbas Ail; Eshaghi, Akbar; Karami, Esmaeil

    2017-09-01

    In this research, a diamond-like carbon thin film was deposited on p-type polycrystalline silicon solar cell via plasma-enhanced chemical vapor deposition method by using methane and hydrogen gases. The effect of atomic oxygen on the functioning of silicon coated DLC thin film and silicon was investigated. Raman spectroscopy, field emission scanning electron microscopy, atomic force microscopy and attenuated total reflection-Fourier transform infrared spectroscopy were used to characterize the structure and morphology of the DLC thin film. Photocurrent-voltage characteristics of the silicon solar cell were carried out using a solar simulator. The results showed that atomic oxygen exposure induced the including oxidation, structural changes, cross-linking reactions and bond breaking of the DLC film; thus reducing the optical properties. The photocurrent-voltage characteristics showed that although the properties of the fabricated thin film were decreased after being exposed to destructive rays, when compared with solar cell without any coating, it could protect it in atomic oxygen condition enhancing solar cell efficiency up to 12%. Thus, it can be said that diamond-like carbon thin layer protect the solar cell against atomic oxygen exposure.

  16. Physical investigation of electrophoretically deposited graphene oxide and reduced graphene oxide thin films

    NASA Astrophysics Data System (ADS)

    Politano, Grazia Giuseppina; Versace, Carlo; Vena, Carlo; Castriota, Marco; Ciuchi, Federica; Fasanella, Angela; Desiderio, Giovanni; Cazzanelli, Enzo

    2016-11-01

    Graphene oxide and reduced graphene oxide thin films are very promising materials because they can be used in optoelectronic devices and in a growing range of applications such as touch screens and flexible displays. In this work, graphene oxide (GO) and thermally reduced graphene oxide (rGO) thin films, deposited on Ti/glass substrates, have been obtained by electrophoretic deposition. The morphological and the structural properties of the samples have been investigated by micro-Raman technique, X-ray reflectometry, and SEM analysis. In order to study the optical and electrical properties, variable angle spectroscopic ellipsometry and impedance analysis have been performed. The thermal annealing changes strongly the structural, electrical, and optical properties, because during the thermal processes some amount of sp3 bonds originally present in GO were removed. In particular, the annealing enhances the Ohmic behavior of the rGO film increasing its conductivity and the estimated optical density. Moreover, using electrophoretic deposition, we have found a higher value of optical density for GO thin films, not observed in GO films obtained with other deposition methods.

  17. TOPICAL REVIEW Charged nanoparticles in thin film and nanostructure growth by chemical vapour deposition

    NASA Astrophysics Data System (ADS)

    Hwang, Nong-Moon; Lee, Dong-Kwon

    2010-12-01

    The critical role of charged nanoclusters and nanoparticles in the growth of thin films and nanostructures by chemical vapour deposition (CVD) is reviewed. Advanced nanoparticle detection techniques have shown that charged gas-phase nuclei tend to be formed under conventional processing conditions of thin films and nanostructures by thermal, hot-wire and plasma CVD. The relation between gas-phase nuclei and thin film and nanostructure growth has not been clearly understood. In this review it will be shown that many films and nanostructures, which have been believed to grow by individual atoms or molecules, actually grow by the building blocks of such charged nuclei. This new growth mechanism was revealed in an attempt to explain many puzzling phenomena involved in the gas-activated diamond CVD process. Therefore, detailed thermodynamic and kinetic analyses will be made to draw the conclusion that the well-known phenomenon of deposition of less stable diamond with simultaneous etching of stable graphite should be an indication of diamond growth exclusively by charged nuclei formed in the gas phase. A similar logic was applied to the phenomenon of simultaneous deposition and etching of silicon, which also leads to the conclusion that silicon films by CVD should grow mainly by the building blocks of charged nuclei. This new mechanism of crystal growth appears to be general in many CVD and some physical vapour deposition (PVD) processes. In plasma CVD, this new mechanism has already been utilized to open a new field of plasma-aided nanofabrication.

  18. Fluorocarbon thin-film deposition on polymer surfaces from low-energy polyatomic ion beams

    NASA Astrophysics Data System (ADS)

    Wijesundara, Muthu Bandage Jayathilaka

    Low energy polyatomic ion deposition is attractive for selective surface modification of advanced materials. Surface modification by fluorocarbon (FC) thin film deposition is widely used for many technological applications. Thus, polymer surface modification by FC thin film deposition was carried out using mass-separated low energy FC ion beams. X-ray photoelectron spectroscopy, atomic force microscopy and air/water contact angles were employed to examine how the FC film chemistry, morphology, and long term stability depend on incident ion structure, kinetic energy, and fluence. Molecular dynamics simulations were performed to support experimental data. 25--100 eV CF3+ and C3F 5+ ion deposition on polystyrene (PS) surface was examined. CF3+ and C3F5+ each formed a distribution of different FC functional groups on PS in amounts dependent upon the incident ion energy, structure, and fluence. Both ions deposited mostly intact upon the surface at 25 eV. The total fluorine and fluorinated carbon content were increased with ion energy. The fluorination efficiency was higher for the larger ion. The simulations revealed that the fragmentation behavior depends on the incident ion structure and its energy. The simulations also confirmed that FC ions only penetrated a few angstroms into the surface. The compositional changes of 25--100 eV CF3+ and C3F5+ ion-modified PS surfaces were examined after being exposed to atmosphere for four and eight weeks. The FC films oxidized in atmospheric conditions. Oxygen incorporation into the ion-modified surfaces increased with ion energy due to higher surface bond breakage and active site formation at high collision energy. Overall, the aging process of these ion-deposited films appeared similar to that of plasma-deposited films. Mass-selected 50 eV C3F5+ ion deposition was employed to create chemical gradient thin films on polymethylmethacrylate (PMMA) by variation of the ion fluence across the substrate surface. The surface chemistry

  19. Fabrication of Co thin films using pulsed laser deposition method with or without employing external magnetic field

    NASA Astrophysics Data System (ADS)

    Ehsani, M. H.; Mehrabad, M. Jalali; Kameli, P.

    2016-11-01

    In this work, the external magnetic field effects on growth condition during deposition processes of the Co thin films were studied. Two specimens of Co films with different condition (with and without external magnetic field) were synthesized by pulsed laser deposition method. Structural and magnetic properties of the Co thin films were systematically studied, using atomic force microscope analysis and magnetization measurement, respectively. During the deposition processes, the external applied magnetic field had been provided by a permanent magnet. The experimental results show that the external magnetic field enables one to tune the magnetic properties of the deposited thin films. To clarify this effect, using Multi-Physics COMSOL simulation environment, a study of vapor flux by applied magnetic field during deposition were performed. Comparison between experimental data and output data of the simulation show promising accommodation and approve the existence of a strong correlation between the structural and magnetic properties of the specimens, and deposition rate of Co thin films.

  20. Physical Vapor Deposition of Hexagonal and Tetragonal CuIn5Se8 Thin Films

    NASA Astrophysics Data System (ADS)

    Kohara, Naoki; Nishiawaki, Shiro; Negami, Takayuki; Wada, Takahiro

    2000-11-01

    Hexagonal and tetragonal CuIn5Se8 thin films have been successfully prepared by physical vapor deposition. A hexagonal CuIn5Se8 thin film was obtained via the reaction of (Cu+Se) and (In+Se) layers. This hexagonal film had a layered structure with a lattice spacing of approximately 16 Å, corresponding to fivefold close-packed stacking of Se. With an alternative deposition process using (CuInSe2) and (In2Se3) layers, a tetragonal CuIn5Se8 thin film was obtained. The tetragonal film had a columnar structure with a lattice spacing of 3.3 Å, corresponding to the cubic close-packed stacking of Se. As evident from examination of the Cu2Se-In2Se3 pseudo-binary system phase diagram, hexagonal CuIn5Se8 is a stable phase and tetragonal CuIn5Se8 is metastable. The growth mechanism of the hexagonal and tetragonal phase CuIn5Se8 thin films is discussed from a crystallographic point of view.

  1. Studies on Nanostructure Aluminium Thin Film Coatings Deposited using DC magnetron Sputtering Process

    NASA Astrophysics Data System (ADS)

    Singh M, Muralidhar; G, Vijaya; MS, Krupashankara; Sridhara, B. K.; Shridhar, T. N.

    2016-09-01

    Nanostructured thin film metallic coatings has become an area of intense research particularly in applications related solar, sensor technologies and many other optical applications such as laser windows, mirrors and reflectors. Thin film metallic coatings were deposited using DC magnetron sputtering process. The deposition rate was varied to study its influence on optical behavior of Aluminum thin films at a different argon flow rate. Studies on the optical response of these nanostructure thin film coatings were characterized using UV-VIS-NIR spectrophotometer with integrating sphere in the wavelength range of (250-2500nm) and Surface morphology were carried out using atomic force microscope with roughness ranging from 2 to 20nm and thickness was measured using Dektak measuring instrument. The reflection behavior of aluminium coatings on polycarbonate substrates has been evaluated. UV-VIS-NIR Spectrophotometer analysis indicates higher reflectance of 96% for all the films in the wavelength range of 250 nm to 2500 nm. Nano indentation study revealed that there was a considerable change in hardness values of the films prepared at different conditions.

  2. Metalcone Chemistry: In pursuit of improved mechanical properties in thin film deposition

    NASA Astrophysics Data System (ADS)

    Hall, Robert A.

    Atomic Layer Deposition (ALD) and its subset, Molecular layer deposition (MLD), is a thin film deposition technique using alternating self-limiting precursors to grow thin films on a substrates. Recent research has expanded MLD to use reactive metal alkyls/halides and organic fragments containing alcohol groups such as ethylene glycol for use in protective barriers. Unfortunately using ethylene glycol as a precursor causes film stability issues and does not provide adequate mechanical properties for projected uses. The current research looks into the investigation of using different metal alkyls and metal halides with the trifunctional precursor glycerol. The three main films investigated were the AlGL using trimethylaluminum and glycerol, ZnGL using diethyl zinc and glycerol and TIGL using titanium (IV) chloride and glycerol. The films were investigated using quartz crystal microbalance, X-ray reflectivity, and spectroscopic ellipsometry for characterization of their film growth. All films exhibited linear growth at a range of temperatures above 130°C with AlGL, ZnGL and TiGL displaying a growth rate at 150°C of ˜2.34A/cycle, ˜1.29A/cycle, and ˜2.2A/cycle respectfully. Initially film growth was investigated in situ using quartz crystal microbalance and then the growth rates confirmed ex situ using X-ray reflectivity. Once the film growth and mechanism were investigated, the mechanical properties were investigated to determine if there was an improvement in cross-linking in the films. The mechanical properties of these MLD films were also investigated using a mechanical testing system and nanoindenter. The mechanical properties for AlGL and ZnGL showed a large improvement from 0.69% to 1.2% for their critical tensile strain compared to previous MLD films. The films also showed an increase in mechanical properties from their nanoindentation results consistent with an increase in cross-linking.

  3. Study on the effect of film formation process and deposition rate on the orientation of the CsI:Tl thin film

    NASA Astrophysics Data System (ADS)

    Tan, Xiaochuan; Liu, Shuang; Xie, Yijun; Guo, Lina; Ma, Shijun; Wang, Tianyu; Liu, Yong; Zhong, Zhiyong

    2017-10-01

    Although many new scintillation materials are developed, CsI:Tl is still prevailing because of its high scintillation efficiency. In this work, CsI:Tl thin films were fabricated by vacuum thermal evaporative deposition method and their morphology properties and growth orientation were observed by SEM and XRD. Photoluminescent spectra were used to measure the luminescent properties of the CsI:Tl thin film. The results show us the film formation process of CsI:Tl thin film and analyze the effect of film formation process and the deposition rate on the orientation of the CsI:Tl thin film.

  4. Properties of NiO thin films deposited by chemical spray pyrolysis using different precursor solutions

    NASA Astrophysics Data System (ADS)

    Cattin, L.; Reguig, B. A.; Khelil, A.; Morsli, M.; Benchouk, K.; Bernède, J. C.

    2008-07-01

    NiO thin films have been deposited by chemical spray pyrolysis using a perfume atomizer to grow the aerosol. The influence of the precursor, nickel chloride hexahydrate (NiCl 2·6H 2O), nickel nitrate hexahydrate (Ni(NO 3) 2·6H 2O), nickel hydroxide hexahydrate (Ni(OH) 2·6H 2O), nickel sulfate tetrahydrate (NiSO 4·4H 2O), on the thin films properties has been studied. In the experimental conditions used (substrate temperature 350 °C, precursor concentration 0.2-0.3 M, etc.), pure NiO thin films crystallized in the cubic phase can be achieved only with NiCl 2 and Ni(NO 3) 2 precursors. These films have been post-annealed at 425 °C for 3 h either in room atmosphere or under vacuum. If all the films are p-type, it is shown that the NiO films conductivity and optical transmittance depend on annealing process. The properties of the NiO thin films annealed under room atmosphere are not significantly modified, which is attributed to the fact that the temperature and the environment of this annealing is not very different from the experimental conditions during spray deposition. The annealing under vacuum is more efficient. This annealing being proceeded in a vacuum no better than 10 -2 Pa, it is supposed that the modifications of the NiO thin film properties, mainly the conductivity and optical transmission, are related to some interaction between residual oxygen and the films.

  5. Electrochemical impedance analysis of spray deposited CZTS thin film: Effect of Se introduction

    NASA Astrophysics Data System (ADS)

    Patil, Swati J.; Lokhande, Vaibhav C.; Lee, Dong-Weon; Lokhande, Chandrakant D.

    2016-08-01

    The present work deals with electrochemical impedance analysis of spray deposited Cu2ZnSnS4 (CZTS) thin films grown on fluorine doped tin oxide (FTO) substrates and effect of post Se introduction. The CZTS thin films are characterized using X-ray diffraction (XRD), X-Ray photo spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and UV-Vis spectroscopy techniques. The electrochemical measurements are carried out using impedance analysis spectroscopy. The strong peak in XRD pattern along (112) plane confirms the Kestrite crystal structure of CZTS film. The FE-SEM analysis reveals that nanoflakes contain crack-free surface microstructure changes with post Se introucation. The optical study reveals that absorption increases with Se dipping time and observed lower band gap of 1.31 eV. Introduction of Se in CZTS film results an improvement in the grain size and surface morphology which leads to increased electrical conductivity of CZTS film.

  6. Hall mobility of cuprous oxide thin films deposited by reactive direct-current magnetron sputtering

    SciTech Connect

    Lee, Yun Seog; Winkler, Mark T.; Siah, Sin Cheng; Brandt, Riley; Buonassisi, Tonio

    2011-05-09

    Cuprous oxide (Cu{sub 2}O) is a promising earth-abundant semiconductor for photovoltaic applications. We report Hall mobilities of polycrystalline Cu{sub 2}O thin films deposited by reactive dc magnetron sputtering. High substrate growth temperature enhances film grain structure and Hall mobility. Temperature-dependent Hall mobilities measured on these films are comparable to monocrystalline Cu{sub 2}O at temperatures above 250 K, reaching 62 cm{sup 2}/V s at room temperature. At lower temperatures, the Hall mobility appears limited by carrier scattering from ionized centers. These observations indicate that sputtered Cu{sub 2}O films at high substrate growth temperature may be suitable for thin-film photovoltaic applications.

  7. Pulsed laser deposition of air-sensitive hydride epitaxial thin films: LiH

    SciTech Connect

    Oguchi, Hiroyuki; Isobe, Shigehito; Kuwano, Hiroki; Shiraki, Susumu; Hitosugi, Taro; Orimo, Shin-ichi

    2015-09-01

    We report on the epitaxial thin film growth of an air-sensitive hydride, lithium hydride (LiH), using pulsed laser deposition (PLD). We first synthesized a dense LiH target, which is key for PLD growth of high-quality hydride films. Then, we obtained epitaxial thin films of [100]-oriented LiH on a MgO(100) substrate at 250 °C under a hydrogen pressure of 1.3 × 10{sup −2} Pa. Atomic force microscopy revealed that the film demonstrates a Stranski-Krastanov growth mode and that the film with a thickness of ∼10 nm has a good surface flatness, with root-mean-square roughness R{sub RMS} of ∼0.4 nm.

  8. Investigation on vanadium oxide thin films deposited by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Margoni, Mudaliar Mahesh; Mathuri, S.; Ramamurthi, K.; Babu, R. Ramesh; Sethuraman, K.

    2016-05-01

    Vanadium oxide thin films were deposited at 400 °C by spray pyrolysis technique using 0.1 M aqueous precursor solution of ammonium meta vanadate (AMV) with two different pH values. X-ray diffraction results showed that the film prepared using aqueous precursor AMV solution (solution A; pH 7) is amorphous in nature and the film prepared by adding HNO3 in the AMV aqua solution A (solution B; pH 3) is polycrystalline in nature. Vanadium oxide film prepared from the precursor solution B is in the mixed phases of V2O5 and V4O7. Crystallinity is improved for the film prepared using solution B when compared to film prepared from solution A. Crystallite size, strain and dislocation density calculated for the film prepared from solution B is respectively 72.1 nm, 0.4554 × 10-3 lin.-2m-4 and 1.7263 × 1014 lin.m-2. Morphology study revealed that the size of the flakes formed on the surface of the films is influenced by the pH of the precursor solution. Average Visible Transmittance and maximum transmittance of the deposited films exceed 70% and the direct optical band gap value calculated for the films deposited from A and B solution is 1.91 eV and 2.08 eV respectively.

  9. Alternate deposition and hydrogen doping technique for ZnO thin films

    NASA Astrophysics Data System (ADS)

    Myong, Seung Yeop; Lim, Koeng Su

    2006-08-01

    We propose an alternate deposition and hydrogen doping (ADHD) technique for polycrystalline hydrogen-doped ZnO thin films, which is a sublayer-by-sublayer deposition based on metalorganic chemical vapor deposition and mercury-sensitized photodecomposition of hydrogen doping gas. Compared to conventional post-deposition hydrogen doping, the ADHD process provides superior electrical conductivity, stability, and surface roughness. Photoluminescence spectra measured at 10 K reveal that the ADHD technique improves ultraviolet and violet emissions by suppressing the green and yellow emissions. Therefore, the ADHD technique is shown to be very promising aid to the manufacture of improved transparent conducting electrodes and light emitting materials.

  10. Non-vacuum deposition methods for thin film solar cell: Review

    NASA Astrophysics Data System (ADS)

    Yang, Ruisheng; Mazalan, Elham; Chaudhary, Kashif Tufail; Haider, Zuhaib; Ali, Jalil

    2017-03-01

    Solar power is a promising abundant, pollution free, inexhaustible and clean source of energy. Development of cost-effective solar system with high conversion efficiency is the key challenge in field of solar panel manufacturing industry. Different non-vacuum deposition methods have been developed to reduce the cost of solar panel system along with high conversion efficiency. In this paper, a review is presented with major focus on three non-vacuum deposition methods, as spin coating, dip coating and spray coating. Each mentioned deposition technique is discussed in details along with role of different deposition parameters on the characteristics of grown solar thin films.

  11. Nucleation and strain-stabilization during organic semiconductor thin film deposition

    PubMed Central

    Li, Yang; Wan, Jing; Smilgies, Detlef-M.; Bouffard, Nicole; Sun, Richard; Headrick, Randall L.

    2016-01-01

    The nucleation mechanisms during solution deposition of organic semiconductor thin films determine the grain morphology and may influence the crystalline packing in some cases. Here, in-situ optical spectromicroscopy in reflection mode is used to study the growth mechanisms and thermal stability of 6,13-bis(trisopropylsilylethynyl)-pentacene thin films. The results show that the films form in a supersaturated state before transforming to a solid film. Molecular aggregates corresponding to subcritical nuclei in the crystallization process are inferred from optical spectroscopy measurements of the supersaturated region. Strain-free solid films exhibit a temperature-dependent blue shift of optical absorption peaks due to a continuous thermally driven change of the crystalline packing. As crystalline films are cooled to ambient temperature they become strained although cracking of thicker films is observed, which allows the strain to partially relax. Below a critical thickness, cracking is not observed and grazing incidence X-ray diffraction measurements confirm that the thinnest films are constrained to the lattice constants corresponding to the temperature at which they were deposited. Optical spectroscopy results show that the transition temperature between Form I (room temperature phase) and Form II (high temperature phase) depends on the film thickness, and that Form I can also be strain-stabilized up to 135 °C. PMID:27600905

  12. Nucleation and strain-stabilization during organic semiconductor thin film deposition

    NASA Astrophysics Data System (ADS)

    Li, Yang; Wan, Jing; Smilgies, Detlef-M.; Bouffard, Nicole; Sun, Richard; Headrick, Randall L.

    2016-09-01

    The nucleation mechanisms during solution deposition of organic semiconductor thin films determine the grain morphology and may influence the crystalline packing in some cases. Here, in-situ optical spectromicroscopy in reflection mode is used to study the growth mechanisms and thermal stability of 6,13-bis(trisopropylsilylethynyl)-pentacene thin films. The results show that the films form in a supersaturated state before transforming to a solid film. Molecular aggregates corresponding to subcritical nuclei in the crystallization process are inferred from optical spectroscopy measurements of the supersaturated region. Strain-free solid films exhibit a temperature-dependent blue shift of optical absorption peaks due to a continuous thermally driven change of the crystalline packing. As crystalline films are cooled to ambient temperature they become strained although cracking of thicker films is observed, which allows the strain to partially relax. Below a critical thickness, cracking is not observed and grazing incidence X-ray diffraction measurements confirm that the thinnest films are constrained to the lattice constants corresponding to the temperature at which they were deposited. Optical spectroscopy results show that the transition temperature between Form I (room temperature phase) and Form II (high temperature phase) depends on the film thickness, and that Form I can also be strain-stabilized up to 135 °C.

  13. Thermoelectric properties of V2O5 thin films deposited by thermal evaporation

    NASA Astrophysics Data System (ADS)

    Santos, R.; Loureiro, J.; Nogueira, A.; Elangovan, E.; Pinto, J. V.; Veiga, J. P.; Busani, T.; Fortunato, E.; Martins, R.; Ferreira, I.

    2013-10-01

    This work reports the structural, optical, electrical and thermoelectric properties of vanadium pentoxide (V2O5) thin films deposited at room temperature by thermal evaporation on Corning glass substrates. A post-deposition thermal treatment up to 973 K under atmospheric conditions induces the crystallization of the as-deposited amorphous films with an orthorhombic V2O5 phase with grain sizes around 26 nm. As the annealing temperature rises up to 773 K the electrical conductivity increases. The films exhibit thermoelectric properties with a maximum Seebeck coefficient of -218 μV/K and electrical conductivity of 5.5 (Ω m)-1. All the films show NIR-Vis optical transmittance above 60% and optical band gap of 2.8 eV.

  14. Bismuth Oxide Thin Films Deposited on Silicon Through Pulsed Laser Ablation, for Infrared Detectors

    NASA Astrophysics Data System (ADS)

    Condurache-Bota, Simona; Constantinescu, Catalin; Tigau, Nicolae; Praisler, Mirela

    2016-12-01

    Infrared detectors are used in many human activities, from industry to military, telecommunications, environmental studies and even medicine. Bismuth oxide thin films have proved their potential for optoelectronic applications, but their uses as infrared sensors have not been thoroughly studied so far. In this paper, pulsed laser ablation of pure bismuth targets within a controlled oxygen atmosphere is proposed for the deposition of bismuth oxide films on Si (100) substrates. Crystalline films were obtained, whose uniformity depends on the deposition conditions (number of laser pulses and the use of a radio-frequency (RF) discharge of the oxygen inside the deposition chamber). The optical analysis proved that the refractive index of the films is higher than 3 and that their optical bandgap is around 1eV, recommending them for infrared applications.

  15. Influence of precursor concentration on the properties of spray deposited CdO thin films

    SciTech Connect

    Helen, S. J.; Devadason, Suganthi Mahalingam, T.

    2015-06-24

    Cadmium oxide (CdO) thin films of thickness 50 to 200 nm were deposited on glass substrates maintained at 400°C using spray pyrolysis technique. CdO thin films were deposited by varying the molar concentrations of cadmium acetate solution such as 0.01, 0.05, 0.1, 0.15 and 0.2 M. X-ray diffraction studies reveal that the films are polycrystalline in nature with cubic structure. SEM images show that the films have well defined spherical grains and grain boundaries are seen. Optical studies reveal that the films prepared from solution of 0.01 and 0.1M concentration have high transparency than films prepared at other solution concentration. The optical energy band gap value decreases from 2.50 to 2.37eV with the increase in molar concentration. Electrical studies revealed that the CdO thin film prepared using 0.1M solution possesses lowest resistivity.

  16. Physical properties of vacuum evaporated CdTe thin films with post-deposition thermal annealing

    NASA Astrophysics Data System (ADS)

    Chander, Subhash; Dhaka, M. S.

    2015-09-01

    This paper presents the physical properties of vacuum evaporated CdTe thin films with post-deposition thermal annealing. The thin films of thickness 500 nm were grown on glass and indium tin oxide (ITO) coated glass substrates employing thermal vacuum evaporation technique followed by post-deposition thermal annealing at temperature 450 °C. These films were subjected to the X-ray diffraction (XRD),UV-Vis spectrophotometer, source meter and atomic force microscopy (AFM) for structural, optical, electrical and surface morphological analysis respectively. The X-ray diffraction patterns reveal that the films have zinc-blende structure of single cubic phase with preferred orientation (111) and polycrystalline in nature. The crystallographic and optical parameters are calculated and discussed in brief. The optical band gap is found to be 1.62 eV and 1.52 eV for as-grown and annealed films respectively. The I-V characteristics show that the conductivity is decreased for annealed thin films. The AFM studies reveal that the surface roughness is observed to be increased for thermally annealed films.

  17. Synthesis of CuInS2 thin films by spray pyrolysis deposition system

    NASA Astrophysics Data System (ADS)

    Hussain, K. M. A.; Podder, J.; Saha, D. K.

    2013-02-01

    Copper indium disulfide (CuInS2) thin films were deposited on the glass substrate by the locally made spray pyrolysis deposition system. The films were characterized by using energy dispersive analytical X-ray (EDAX) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-VIS-NIR spectrophotometry. The XRD pattern indicated that the prepared CuInS2 thin films are chalcopyrite structure. Lattice parameters and FWHM values were verified by the standard values of JCPDS 270159 file. The EDAX analysis indicated the stoichiometric ratio of 1.14:1:1.88 (CIS-2) thin films. The SEM analysis showed that the average grain size of the film was 100-800 nm and that of XRD data indicate the values of 30-50 nm. The high absorption co-efficient and 1.48 eV band gap of the films indicate that the films are useful as an absorber for photovoltaic application in the solar cell.

  18. Photoelectrochemical properties of spray deposited n-CdSe thin films

    SciTech Connect

    Yadav, A.A.; Barote, M.A.; Masumdar, E.U.

    2010-05-15

    Polycrystalline cadmium selenide (CdSe) thin films have been prepared by spraying a mixture of an equimolar aqueous solutions of cadmium chloride and selenourea on preheated fluorine doped tin oxide (FTO) coated glass substrates at different substrate temperatures. The cell configuration n-CdSe/1 M (NaOH + Na{sub 2}S + S)/C is used for studying the capacitance-voltage (C-V) characteristics in dark, current-voltage (I-V) characteristics in dark and under illumination, photovoltaic power output and spectral response characteristics of the as deposited films. Photoelectrochemical study shows that as deposited CdSe thin films exhibits n-type of conductivity. The spectral response characteristics of the films at room temperature show a prominent sharp peak at 725 nm. The measured values of efficiency ({eta}) and fill factor (FF) are found to be 0.50% and 0.44 respectively for film deposited at 300 C. Electrochemical impedance spectroscopy studies show that the CdSe film deposited at 300 C shows better performance in PEC cell. (author)

  19. Post-deposition annealing study of tantalum nitride thin-film resistors

    SciTech Connect

    Au, Chi Lok.

    1989-01-01

    With the present integrated circuit design, the use of hybrid metallic thin film resistor networks leads to more design flexibility, economical chip area consumption, reduced processing steps, higher precision and stability for the integrated circuits. To meet the hybrid circuit requirements, the thin film resistors must have high sheet resistivity for compact design, chemical and mechanical stability, and precise resistance which is temperature independent. The nickel-chrome (NiCr) alloy, with its very low temperature coefficient of resistance (TCR), is currently used in the industry. The non-linear TCR behavior and the ease of hydrolytic dissociation of NiCr give place to a more stable material, such as tantalum nitride. Due to technical difficulties in heating the substrate to a high temperature during deposition, which is the controlling parameter for achieving the stable Ta{sub 2}N structure, post deposition annealing becomes the central theme for this project. Preliminary TCR studies of the reactive sputtered tantalum nitride thin films shows that films with sheet resistivity less than 60 ohm/sq. can be air annealed to improve the TCR to less than 30 ppm/{degree}C in magnitude. The deposition parameters may influence the annealing conditions. For films with higher sheet resistivity, high vacuum annealing must be used for the TCR improvement. The TCR can be adjusted to an almost zero value by the combination of annealing temperature and time. With the electrical stability and chemically inertness in water and acids, tantalum nitride is likely to become a major thin-film resistor material in the industry. A systematic study of this thin film material is conducted, covering both electrical and structural properties.

  20. Polymer-assisted deposition of co-doped zinc oxide thin films for the detection of aromatic organic compounds.

    PubMed

    Li, Wei; Kim, Dojin

    2011-12-01

    Co-doped Zinc oxide thin films are deposited onto SiO2/Si substrate by polymer-assisted deposition method. The surface morphology, structures and chemical states of the thin films are examined by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The gas-sensing properties of the thin films upon exposure to aromatic organic compound vapors are also investigated. Co-doping is shown to be very effective in enhancing the response of ZnO thin film to aromatic organic compound.

  1. Pulsed laser deposited cobalt-doped ZnO thin film

    NASA Astrophysics Data System (ADS)

    Wang, Li; Su, Xue-qiong; Lu, Yi; Chen, Jiang-bo

    2013-09-01

    To realize the room-temperature ferromagnetism (RTFM) in diluted magnetic semiconductors (DMS), we prepared a series of Cobalt-doped ZnO thin films using pulsed laser deposition (PLD) at deposition temperatures 500°C under oxygen pressure from 2.5×10-4 Pa to 15 Pa. To elucidate the physical origin of RTFM, Co 2p spectra of cobalt-doped ZnO thin films was measured by X-ray photoelectron spectroscopy (XPS). The magnetic properties of films were measured by an alternating gradient magnetometer (AGM), and the electrical properties were detected by a Hall Effect instrument using the Van der Pauw method. XPS analysis shows that the Co2+ exists and Co clusters and elemental content change greatly in samples under various deposition oxygen pressures. Not only the valence state and elemental content but also the electrical and magnetic properties were changed. In the case of oxygen pressure 10 Pa, an improvement of saturation magnetic moment about one order of magnitude over other oxygen pressure experiments, and the film exhibits ferromagnetism with a curie temperature above room temperature. It was found that the value of carrier concentration in the Co-doped ZnO film under oxygen pressure 10Pa increases about one order of magnitude than the values of other samples under different oxygen pressure. Combining XPS with AGM measurements, we found that the ferromagnetic signals in cobalt-doped ZnO thin film deposited at 500 °C under oxygen pressure 10 Pa only appear with the detectable Co2+ spectra from incompletely oxidized Co metal or Co cluster. So oxygen pressure 10 Pa can be thought the best condition to obtain room-temperature dilute magnetic semiconductor about cobalt-doped ZnO thin films.

  2. Cell proliferation on modified DLC thin films prepared by plasma enhanced chemical vapor deposition.

    PubMed

    Stoica, Adrian; Manakhov, Anton; Polčák, Josef; Ondračka, Pavel; Buršíková, Vilma; Zajíčková, Renata; Medalová, Jiřina; Zajíčková, Lenka

    2015-06-12

    Recently, diamondlike carbon (DLC) thin films have gained interest for biological applications, such as hip and dental prostheses or heart valves and coronary stents, thanks to their high strength and stability. However, the biocompatibility of the DLC is still questionable due to its low wettability and possible mechanical failure (delamination). In this work, DLC:N:O and DLC: SiOx thin films were comparatively investigated with respect to cell proliferation. Thin DLC films with an addition of N, O, and Si were prepared by plasma enhanced CVD from mixtures of methane, hydrogen, and hexamethyldisiloxane. The films were optically characterized by infrared spectroscopy and ellipsometry in UV-visible spectrum. The thickness and the optical properties were obtained from the ellipsometric measurements. Atomic composition of the films was determined by Rutherford backscattering spectroscopy combined with elastic recoil detection analysis and by x-ray photoelectron spectroscopy. The mechanical properties of the films were studied by depth sensing indentation technique. The number of cells that proliferate on the surface of the prepared DLC films and on control culture dishes were compared and correlated with the properties of as-deposited and aged films. The authors found that the level of cell proliferation on the coated dishes was high, comparable to the untreated (control) samples. The prepared DLC films were stable and no decrease of the biocompatibility was observed for the samples aged at ambient conditions.

  3. Synthesis and Characterization of SnO2 Thin Films by Chemical Bath Deposition

    NASA Astrophysics Data System (ADS)

    Rifai, Aditia; Iqbal, Muhammad; Nugraha; Nuruddin, Ahmad; Suyatman; Yuliarto, Brian

    2011-12-01

    SnO2 thin films were deposited on glass substrate by chemical bath deposition (CBD) with stannous chloride (SnCl2..2H2O) as a precursor and urea (CO(NH2)2) as a buffer. X-Ray Diffraction (XRD) are used to characterize the structure of the films; the surface morphology of the films were observed by Scanning Electron Microscope (SEM). Using this techniques, we specify the effect of stannous chloride concentration and weight ratio of urea/H2O on the crystallinity and morphology of these films. The rutile structure corresponding (110), (101) and (211) planes of SnO2 is obtained. The increasing of stannous chloride concentration and the decreasing weight ratio of urea/H2O is found to improve the crystallinity of the film. The average diameter of grain size is about 96 nm.

  4. Studies of aluminum oxide thin films deposited by laser ablation technique

    NASA Astrophysics Data System (ADS)

    Płóciennik, P.; Guichaoua, D.; Korcala, A.; Zawadzka, A.

    2016-06-01

    This paper presents the structural and optical investigations of the aluminum oxide nanocrystalline thin films. Investigated films were fabricated by laser ablation technique in high vacuum onto quartz substrates. The films were deposited at two different temperatures of the substrates equal to room temperature and 900 K. X-ray Diffraction spectra proved nanocrystalline character and the corundum phase of the film regardless on the substrate temperature during the deposition process. Values of the refractive indices, extinction and absorption coefficients were calculated by using Transmission and Reflection Spectroscopy in the UV-VIS-NIR range of the wavelength. Coupling Prism Method was used for films thickness estimations. Experimental measurements and theoretical calculations of the Third Harmonic Generation were also reported. Obtained results show that the lattice strain may affect obtained values of the third order nonlinear optical susceptibility.

  5. Nitrogen oxides and ammonia sensing characteristics of SILAR deposited ZnO thin film

    NASA Astrophysics Data System (ADS)

    Lupan, O. I.; Shishiyanu, S. T.; Shishiyanu, T. S.

    2007-07-01

    Pure and Sn, Ni doped ZnO thin films were deposited on glass substrates using a novel successive ionic layer adsorption and reaction (SILAR) method at room temperature. Microstructures of the deposited films were optimized by adjusting growth parameters. The variation in resistivity of the ZnO film sensors was performed with rapid photothermal processing (RPP). The effect of rapid photothermal processing was found to have an important role in ZnO based sensor sensitivity to NO 2, NH 3. While the undoped ZnO film surface exhibited higher NH 3 sensitivity than that of NO 2, an enhanced NO 2 sensitivity was noticed for the ZnO films doped with Sn and higher NH 3 sensitivity was obtained by Ni doping.

  6. Chemically deposited cubic structured CdO thin films: Room temperature

    NASA Astrophysics Data System (ADS)

    Bulakhe, R. N.; Lokhande, C. D.

    2013-06-01

    Cadmium oxide (CdO) thin films have been synthesized using a chemical bath deposition (CBD) method at room temperature. The prepared CdO thin film were annealed and further used for the structural, morphological, UVVIS characterization. The thermo emf study was made with the TEP setup. The structural study showed polycrystalline CdO material. Morphological study reveals the prism like morphology. Optical and thermo emf study showed n-type nature with optical band gap of 2.13 eV.

  7. Method and apparatus for fabricating a thin-film solar cell utilizing a hot wire chemical vapor deposition technique

    DOEpatents

    Wang, Qi; Iwaniczko, Eugene

    2006-10-17

    A thin-film solar cell is provided. The thin-film solar cell comprises an a-SiGe:H (1.6 eV) n-i-p solar cell having a deposition rate of at least ten (10) .ANG./second for the a-SiGe:H intrinsic layer by hot wire chemical vapor deposition. A method for fabricating a thin film solar cell is also provided. The method comprises depositing a n-i-p layer at a deposition rate of at least ten (10) .ANG./second for the a-SiGe:H intrinsic layer.

  8. Deposition and characterization of amorphous electroless Ni-Co-P alloy thin film for ULSI application

    NASA Astrophysics Data System (ADS)

    Kumar, Anuj; Suhag, Ashok Kumar; Singh, Amanpal; Sharma, Satinder K.; Kumar, Mukesh; Kumar, Dinesh

    2014-09-01

    Electroless based Ni-Co-P alloy thin films were deposited using sodium hypophosphite as a reducing agent and sodium citrate as a complexing agent in an alkaline plating bath. The effect of solution pH and temperature on the plating rate was examined. The decrease in activation energy (81.35 - 73.54 kJ mole-1) for the Ni-Co-P thin films deposited on corning glass was observed with the increase in pH (8.5-9.38) of the plating bath. There is a significant decrease in sheet resistance of alloy thin films as the post deposition annealing temperature approaches 400 °C. The presence of nickel as well as nickel phosphide peaks and transition from metastable Ni12P5, Ni8P5 and Ni5P2 phases into thermodynamically stable NiP, NiP2, Ni3P phases after annealing at 600 °C was observed in XRD spectra, indicating the crystallization of the thin films. Surface topography analysis shows the variation of grain size in the range 20-40 nm.

  9. A stochastic model of solid state thin film deposition: Application to chalcopyrite growth

    DOE PAGES

    Lovelett, Robert J.; Pang, Xueqi; Roberts, Tyler M.; ...

    2016-04-01

    Developing high fidelity quantitative models of solid state reaction systems can be challenging, especially in deposition systems where, in addition to the multiple competing processes occurring simultaneously, the solid interacts with its atmosphere. Here, we develop a model for the growth of a thin solid film where species from the atmosphere adsorb, diffuse, and react with the film. The model is mesoscale and describes an entire film with thickness on the order of microns. Because it is stochastic, the model allows us to examine inhomogeneities and agglomerations that would be impossible to characterize with deterministic methods. We also demonstrate themore » modeling approach with the example of chalcopyrite Cu(InGa)(SeS)2 thin film growth via precursor reaction, which is a common industrial method for fabricating thin film photovoltaic modules. The model is used to understand how and why through-film variation in the composition of Cu(InGa)(SeS)2 thin films arises and persists. Finally, we believe that the model will be valuable as an effective quantitative description of many other materials systems used in semiconductors, energy storage, and other fast-growing industries.« less

  10. A stochastic model of solid state thin film deposition: Application to chalcopyrite growth

    SciTech Connect

    Lovelett, Robert J.; Pang, Xueqi; Roberts, Tyler M.; Shafarman, William N.; Birkmire, Robert W.; Ogunnaike, Babatunde A.

    2016-04-15

    Developing high fidelity quantitative models of solid state reaction systems can be challenging, especially in deposition systems where, in addition to the multiple competing processes occurring simultaneously, the solid interacts with its atmosphere. In this work, we develop a model for the growth of a thin solid film where species from the atmosphere adsorb, diffuse, and react with the film. The model is mesoscale and describes an entire film with thickness on the order of microns. Because it is stochastic, the model allows us to examine inhomogeneities and agglomerations that would be impossible to characterize with deterministic methods. We demonstrate the modeling approach with the example of chalcopyrite Cu(InGa)(SeS){sub 2} thin film growth via precursor reaction, which is a common industrial method for fabricating thin film photovoltaic modules. The model is used to understand how and why through-film variation in the composition of Cu(InGa)(SeS){sub 2} thin films arises and persists. We believe that the model will be valuable as an effective quantitative description of many other materials systems used in semiconductors, energy storage, and other fast-growing industries.

  11. A stochastic model of solid state thin film deposition: Application to chalcopyrite growth

    NASA Astrophysics Data System (ADS)

    Lovelett, Robert J.; Pang, Xueqi; Roberts, Tyler M.; Shafarman, William N.; Birkmire, Robert W.; Ogunnaike, Babatunde A.

    2016-04-01

    Developing high fidelity quantitative models of solid state reaction systems can be challenging, especially in deposition systems where, in addition to the multiple competing processes occurring simultaneously, the solid interacts with its atmosphere. In this work, we develop a model for the growth of a thin solid film where species from the atmosphere adsorb, diffuse, and react with the film. The model is mesoscale and describes an entire film with thickness on the order of microns. Because it is stochastic, the model allows us to examine inhomogeneities and agglomerations that would be impossible to characterize with deterministic methods. We demonstrate the modeling approach with the example of chalcopyrite Cu(InGa)(SeS)2 thin film growth via precursor reaction, which is a common industrial method for fabricating thin film photovoltaic modules. The model is used to understand how and why through-film variation in the composition of Cu(InGa)(SeS)2 thin films arises and persists. We believe that the model will be valuable as an effective quantitative description of many other materials systems used in semiconductors, energy storage, and other fast-growing industries.

  12. Method of forming ultra thin film devices by vacuum arc vapor deposition

    NASA Technical Reports Server (NTRS)

    Schramm, Harry F. (Inventor)

    2005-01-01

    A method for providing an ultra thin electrical circuit integral with a portion of a surface of an object, including using a focal Vacuum Arc Vapor Deposition device having a chamber, a nozzle and a nozzle seal, depressing the nozzle seal against the portion of the object surface to create an airtight compartment in the chamber and depositing one or more ultra thin film layer(s) only on the portion of the surface of the object, the layers being of distinct patterns such that they form the circuit.

  13. Effect of substrate temperature on deposition rate of rf plasma-deposited hydrogenated amorphous silicon thin films

    NASA Astrophysics Data System (ADS)

    Andújar, J. L.; Bertran, E.; Canillas, A.; Campmany, J.; Morenza, J. L.

    1991-03-01

    We present a study about the influence of substrate temperature on deposition rate of hydrogenated amorphous silicon thin films prepared by rf glow discharge decomposition of pure silane gas in a capacitively coupled plasma reactor. Two different behaviors are observed depending on deposition pressure conditions. At high pressure (30 Pa) the influence of substrate temperature on deposition rate is mainly through a modification of gas density, in such a way that the substrate temperature of deposition rate is similar to pressure dependence at constant temperature. On the contrary, at low pressure (3 Pa), a gas density effect cannot account for the observed increase of deposition rate as substrate temperature rises above 450 K with an activation energy of 1.1 kcal/mole. In accordance with laser-induced fluorescence measurements reported in the literature, this rise has been ascribed to an increase of secondary electron emission from the growing film surface as a result of molecular hydrogen desorption.

  14. Effect of sputter deposited YSZ thin films on the fracture behavior of dental bioceramics

    NASA Astrophysics Data System (ADS)

    Teixeira, Erica Cappelletto Nogueira

    The fracture behavior of dental bioceramic materials was evaluated under physiologic conditions when modified by yttria stabilized zirconia (YSZ) thin film deposition. It was hypothesized that changing the YSZ thin film properties will produce a significant enhancement in the strength of bioceramic materials, ultimately promoting a more fatigue resistant construct. Porcelain, alumina, and zirconia were evaluated in terms of dynamic fatigue for an initial characterization of their fracture behavior. Data showed that strength degradation occurred in all three materials, most drastically in porcelain. Initial strength measurements, focused on depositing YSZ thin films on three unique substrates; porcelain, alumina, and zirconia, were carried out. A significant increase in strength was observed for alumina and porcelain. Since strength alone is not enough to characterize the fracture behavior of brittle materials, coated specimens of porcelain and zirconia were subjected to dynamic fatigue and Weibull analysis. Coated YSZ porcelain specimens showed a significant increase in strength at all tested stressing rates. YSZ coated zirconia specimens showed similar strength values at all stressing rates. The effect of film thickness on porcelain was also evaluated. Data demonstrated that film thickness alone does not appear to control increases in the flexural strength of a modified substrate. It is expected that deposition induced stress in YSZ sputtered films does not change with film thickness. However, a thicker film will generate a larger force at the film/substrate interface, contributing to delamination of the film. It was clear that in order to have a significant improvement in the fracture behavior of porcelain, changing the thickness of the film is not enough. The columnar structure of the YSZ films developed seems to favor an easy path for crack propagation limiting the benefits expected by the coating. The effect of a multilayered film, composed by brittle

  15. Thermal Vapor Deposition and Characterization of Polymer-Ceramic Nanoparticle Thin Films and Capacitors

    NASA Astrophysics Data System (ADS)

    Iwagoshi, Joel A.

    Research on alternative energies has become an area of increased interest due to economic and environmental concerns. Green energy sources, such as ocean, wind, and solar power, are subject to predictable and unpredictable generation intermittencies which cause instability in the electrical grid. This problem could be solved through the use of short term energy storage devices. Capacitors made from composite polymer:nanoparticle thin films have been shown to be an economically viable option. Through thermal vapor deposition, we fabricated dielectric thin films composed of the polymer polyvinylidine fluoride (PVDF) and the ceramic nanoparticle titanium dioxide (TiO2). Fully understanding the deposition process required an investigation of electrode and dielectric film deposition. Film composition can be controlled by the mass ratio of PVDF:TiO2 prior to deposition. An analysis of the relationship between the ratio of PVDF:TiO2 before and after deposition will improve our understanding of this novel deposition method. X-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy were used to analyze film atomic concentrations. The results indicate a broad distribution of deposited TiO2 concentrations with the highest deposited amount at an initial mass concentration of 17% TiO2. The nanoparticle dispersion throughout the film is analyzed through atomic force microscopy and energy dispersive x-ray spectroscopy. Images from these two techniques confirm uniform TiO2 dispersion with cluster size less than 300 nm. These results, combined with spectroscopic analysis, verify control over the deposition process. Capacitors were fabricated using gold parallel plates with PVDF:TiO 2 dielectrics. These capacitors were analyzed using the atomic force microscope and a capacohmeter. Atomic force microscope images confirm that our gold films are acceptably smooth. Preliminary capacohmeter measurements indicate capacitance values of 6 nF and break down voltages of 2.4 V

  16. Evaporation system and method for gas jet deposition of thin film materials

    DOEpatents

    Schmitt, J.J.; Halpern, B.L.

    1994-10-18

    A method and apparatus are disclosed for depositing thin films of materials such as metals, oxides and nitrides at low temperature relies on a supersonic free jet of inert carrier gas to transport vapor species generated from an evaporation source to the surface of a substrate. Film deposition vapors are generated from solid film precursor materials, including those in the form of wires or powders. The vapor from these sources is carried downstream in a low pressure supersonic jet of inert gas to the surface of a substrate where the vapors deposit to form a thin film. A reactant gas can be introduced into the gas jet to form a reaction product with the evaporated material. The substrate can be moved from the gas jet past a gas jet containing a reactant gas in which a discharge has been generated, the speed of movement being sufficient to form a thin film which is chemically composed of the evaporated material and reactant gases. 8 figs.

  17. RF-sputter deposited flexible copper oxide thin films for electrochemical energy storage

    NASA Astrophysics Data System (ADS)

    Purusottam Reddy, B.; Sivajee Ganesh, K.; Park, Si-Hyun; Hussain, O. M.

    2017-07-01

    Flexible Cu-O thin films were grown on different metal coated non rigid polyimide substrates by the RF-magnetron sputtering and their microstructure and supercapacitive properties were studied. The Raman and XRD studies confirms the formation of a single Cu2O phase with predominant (111) orientation. Surface topography observations revealed that as the percentage of lattice mismatch of Cu2O lattice and substrate lattice is greater the average grain size tends to decrease. The Cu2O films deposited on Ti-Kapton, Ni-Kapton and Pt-Kapton substrates exhibited maximum specific capacitances of 255, 273 and 350 F g-1 correspondingly at a constant current density of 1 A g-1. The observed maximum specific capacitance for CuxO thin films deposited on Pt-Kapton substrates is due to the lower lattice mismatch, high work function of the metal, availability of (111) planes and highly available active area.

  18. On the wetting behavior of ceria thin films grown by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Fu, Sin-Pui; Rossero, Jorge; Chen, Chen; Li, Daniel; Takoudis, Christos G.; Abiade, Jeremiah T.

    2017-02-01

    Polymers are most widely used in the production of water-repellant coatings. However, their use in applications requiring wear resistance or high-temperature stability is extremely limited. A recent report suggests that wear resistant, thermally stable rare earth oxide materials like cerium dioxide (ceria) are intrinsically water repellant. We have studied this intriguing finding for ceria thin films fabricated by pulsed laser deposition (PLD) at different oxygen pressures and different substrate temperatures. We used a custom apparatus for measuring water contact angles on ceria films deposited by PLD. X-ray photoelectron spectroscopy was used to determine the relationship between the ceria wetting behavior and ceria surface chemistry. Our results show that ceria thin films are intrinsically hydrophilic and that hydrophobicity arises due to adsorption of hydrocarbon species after ˜24 h.

  19. Glancing angle deposition of sculptured thin metal films at room temperature.

    PubMed

    Liedtke, S; Grüner, Ch; Lotnyk, A; Rauschenbach, B

    2017-09-20

    Metallic thin films consisting of separated nanostructures are fabricated by evaporative glancing angle deposition at room temperature. The columnar microstructure of the Ti and Cr columns is investigated by high resolution transmission electron microscopy and selective area electron diffraction. The morphology of the sculptured metallic films is studied by scanning electron microscopy. It is found that tilted Ti and Cr columns grow with a single crystalline morphology, while upright Cr columns are polycrystalline. Further, the influence of continuous substrate rotation on the shaping of Al, Ti, Cr and Mo nanostructures is studied with view to surface diffusion and the shadowing effect. It is observed that sculptured metallic thin films deposited without substrate rotation grow faster compared to those grown with continuous substrate rotation. A theoretical model is provided to describe this effect.

  20. Negative ions: The overlooked species in thin film growth by pulsed laser deposition

    SciTech Connect

    Esposito, M.; Bator, M.; Lippert, T.; Schneider, C. W.; Wokaun, A.; Doebeli, M.

    2011-11-07

    Plasma plume species from a ceramic La{sub 0.4}Ca{sub 0.6}MnO{sub 3} target were studied by plasma mass spectrometry as a function of laser fluence, background gas, and deposition pressure to understand the interplay between plasma composition and oxide thin film growth by pulsed laser deposition. The plume composition reveals a significant contribution of up to 24% of negative ions, most notably using a N{sub 2}O background. The significance of negative ions for thin film growth is shown for La{sub 0.4}Ca{sub 0.6}MnO{sub 3} films grown in different background conditions where the best structural properties coincide with the largest amount of negative plasma species.

  1. Crystalline growth of AlN thin films by atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Sadeghpour, S.; Ceyssens, F.; Puers, R.

    2016-10-01

    Aluminum nitride (AlN) thin film was grown by plasma enhanced atomic layer deposition using trimethylaluminum and ammonia precursors. A method was found to have crystalline thin film AlN with almost zero thickness variation and a truly one layer deposition of atoms per each cycle of the process. The growth rate saturated at ∼ 1 Å/cycle, and the thickness was proportional to the number of reaction cycles. The preferred crystal orientation, uniformity of the nucleation and the surface roughness of the grown AlN were investigated. X-ray diffraction (XRD), atomic focused microscopy (AFM) and scanning electron microscopy (SEM) were carried out to analyze the crystallinity and properties of the films.

  2. Test-photostability of pulsed laser deposited amorphous thin films from Ge-As-Te system.

    PubMed

    Hawlová, P; Verger, F; Nazabal, V; Boidin, R; Němec, P

    2015-03-23

    Amorphous thin films from Ge-As-Te system were prepared by pulsed laser deposition to study their intrinsic photostability, morphology, chemical composition, structure and optical properties. Photostability of fabricated layers was studied by spectroscopic ellipsometry within as-deposited as well as relaxed (annealed) layers. For irradiation, laser sources operating at three wavelengths in band gap region of the studied materials were employed. The results show that lowest values of photorefraction accompanied with lowest changes of band gap values were exhibited by Ge20As20Te60 thin films, which are therefore considered as the layers with highest photostability in relaxed state. The structure of the films is discussed based on Raman scattering spectroscopy data.

  3. Formation and stability of lanthanum oxide thin films deposited from β-diketonate precursor

    NASA Astrophysics Data System (ADS)

    Nieminen, Minna; Putkonen, Matti; Niinistö, Lauri

    2001-04-01

    Lanthanum oxide thin film deposition by atomic layer epitaxy (ALE) was studied at 180-425°C on soda-lime glass and Si(1 0 0) substrates using a β-diketonate type precursor La(thd) 3 and ozone. The chemical constituents of the films were analyzed by TOF-ERDA, RBS and FTIR while XRD and AFM were used to determine the crystallinity and surface morphology. Films grown below 275°C were amorphous La 2O 2CO 3, while at deposition temperatures above 300°C XRD patterns indicated that cubic La 2O 3 phase was formed. All the films were transparent and uniform with only small thickness variations. Carbonate type impurity was found in all films, but the carbon content of the films decreased with growth temperature being 3 at.% in films grown above 400°C. Hexagonal La 2O 3 was obtained when the films grown on silicon substrates were annealed at 800°C or above in a nitrogen flow. The as-deposited cubic and annealed hexagonal La 2O 3 films were found to be chemically unstable in ambient air since a transformation to monoclinic LaO(OH) and hexagonal La(OH) 3 was detected, respectively.

  4. CuInS 2 thin films obtained through the annealing of chemically deposited In 2S 3-CuS thin films

    NASA Astrophysics Data System (ADS)

    Peña, Y.; Lugo, S.; Calixto-Rodriguez, M.; Vázquez, A.; Gómez, I.; Elizondo, P.

    2011-01-01

    In this work, we report the formation of CuInS 2 thin films on glass substrates by heating chemically deposited multilayers of copper sulfide (CuS) and indium sulfide (In 2S 3) at 300 and 350 °C in nitrogen atmosphere at 10 Torr. CIS thin films were prepared by varying the CuS layer thickness in the multilayers with indium sulfide. The XRD analysis showed that the crystallographic structure of the CuInS 2 (JCPDS 27-0159) is present on the deposited films. From the optical analysis it was estimated the band gap value for the CIS film (1.49 eV). The electrical conductivity varies from 3 × 10 -8 to 3 Ω -1 cm -1 depending on the thickness of the CuS film. CIS films showed p-type conductivity.

  5. Tailoring the LCST of thermosensitive hydrogel thin films deposited by iCVD.

    PubMed

    Pena-Francesch, Abdon; Montero, Laura; Borrós, Salvador

    2014-06-24

    Using the iCVD (initiated chemical vapor deposition) polymerization technique, we generated a library of thermosensitive thin film hydrogels in the physiological temperature range. The library shows how a specific hydrogel with a desired temperature response can be synthesized via the copolymerization of three main components: (a) the main thermosensitive monomer, which determines the temperature range of the LCST; (b) the comonomer, which modulates the temperature according to its hydrophilic/hydrophobic behavior; and (c) the cross-linker, which determines the swelling degree and the polymer chain mobility of the resulting hydrogel. The thermosensitive thin films included in the library have been characterized by the water contact angle (WCA), revealing a switchable hydrophobic/hydrophilic behavior depending on the temperature and a decrease in the WCA with the incorporation of hydrophilic moieties. Moreover, a more accurate characterization by quartz crystal microbalance (QCM) is performed. With temperature and flow control, the switchable swelling properties of the thermosensitive thin films (due to the polymer mixture transition) can be recorded and analyzed in order to study the effects of the comonomer moieties on the lower critical solution temperature (LCST). Thus, the LCST tailoring method has been successfully used in this paper, and thermoresponsive thin films (50 nm in thickness) have been deposited by iCVD, exhibiting LCSTs in the 32-49 °C range. Due to the presented method's ability to tailor the LCST in the physiological temperature range, the developed thermoresponsive films present potential biosensing and drug delivery applications in the biomedical field.

  6. Synthesis and Characterization of In2S3 Thin Films Deposited by Chemical Bath Deposition on Polyethylene Naphthalate Substrates

    NASA Astrophysics Data System (ADS)

    Castelo-González, O. A.; Santacruz-Ortega, H. C.; Quevedo-López, M. A.; Sotelo-Lerma, M.

    2012-04-01

    Indium sulfide (In2S3) thin films were deposited on polyethylene naphthalate (PEN) by chemical bath deposition (CBD). The materials were characterized by ultraviolet (UV)-visible spectroscopy, x-ray photoelectron spectroscopy (XPS), energy-dispersive x-ray spectroscopy (EDX), scanning electron microscopy (SEM), and x-ray diffraction (XRD) to investigate the influence of the polymeric substrate on the resulting thin In2S3. The films showed polycrystalline (cubic and tetragonal) structure. A reduction of the ordering of the polymeric chains at the surface of the PEN was also observed, demonstrated by the appearance of two infrared bands at 1094 cm-1 and 1266 cm-1. Presence of oxygen during the early stages of In2S3 growth was also identified. We propose a reaction mechanism for both the equilibrium and nucleation stages. These results demonstrate that In2S3 can be deposited at room temperature on a flexible substrate.

  7. Nano-indentation of single-layer optical oxide thin films grown by electron-beam deposition

    SciTech Connect

    Mehrotra, K.; Oliver, J. B.; Lambropoulos, J. C.

    2015-01-01

    Mechanical characterization of optical oxide thin films is performed using nano-indentation, and the results are explained based on the deposition conditions used. These oxide films are generally deposited to have a porous microstructure that optimizes laser induced damage thresholds, but changes in deposition conditions lead to varying degrees of porosity, density, and possibly the microstructure of the thin film. This can directly explain the differences in the mechanical properties of the film studied here and those reported in literature. Of the four single-layer thin films tested, alumina was observed to demonstrate the highest values of nano-indentation hardness and elastic modulus. This is likely a result of the dense microstructure of the thin film arising from the particular deposition conditions used.

  8. Hydrogen gas sensors based on electrostatically spray deposited nickel oxide thin film structures

    NASA Astrophysics Data System (ADS)

    Jamal, Raied K.; Aadim, Kadhim A.; Al-Zaidi, Qahtan G.; Taaban, Iman N.

    2015-09-01

    A simple, low-cost, and home-built electrostatic spray deposition (ESD) system with the stable cone-jet mode was used to deposit nickel oxide (NiO) thin films on glass substrates kept at temperature of 400 °C as the primary precursor solution of 0.1 M concentration hydrated nickel chloride was dissolved in isopropyl alcohol. Electrical measurements showed that these films were of n-type conductivity while their resistance response to hydrogen flow in air ambient was varied by 2.81% with the rise and recovery time of 48 s and 40 s, respectively.

  9. Morphological and structural studies of WO x thin films deposited by laser ablation

    NASA Astrophysics Data System (ADS)

    Filipescu, M.; Orlando, S.; Russo, V.; Lamperti, A.; Purice, A.; Moldovan, A.; Dinescu, M.

    2007-07-01

    Tungsten oxide is an interesting compound with many applications in gas sensors, electrochromic and photochromic devices. Thin films of tungsten oxide were obtained by pulsed laser deposition (PLD) and radio frequency assisted PLD (RF-PLD). A tungsten target was ablated in reactive oxygen atmosphere (0.01-0.05 mbar). The deposition parameters such as laser fluence, substrate temperature, radiofrequency power were varied, while different materials (Corning glass and silicon) have been used as substrates. The obtained films showed good adhesion to the substrate and uniform surface aspect, which are important properties for applications. X-ray diffraction, Auger electron, Raman spectroscopies and atomic force microscopy were used for characterization.

  10. Control of crystalline volume and nano crystal grain size in nanocrystalline silicon thin film deposited by PECVD

    NASA Astrophysics Data System (ADS)

    Bui, Thanh Tung; Chien Dang, Mau

    2014-11-01

    Application of the radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) technique was studied to fabricate amorphous and nanocrystalline silicon (a-Si and nc-Si) thin films for photovoltaic devices at substrate temperature of 200 °C. Amorphous-crystalline transition of silicon thin films in working conditions of PECVD system was shown as a function of deposition parameters, i.e., dilution ratio of silane (SiH4) in hydrogen, total gas pressure during deposition and RF excitation power density. The crystalline volume as well as grain size of nanocrystalline silicon films could be successfully controlled by tuning those deposition parameters. Micro Raman scattering spectroscopy and spectroscopic ellipsometry (SE) methods were used to characterize the structure and crystallization of the deposited silicon thin films. We could make nc-Si thin films with various crystalline volumes. Nc-Si grain size was also controlled and was in the range of 3-5 nm.

  11. Study of the morphology of ZnS thin films deposited on different substrates via chemical bath deposition.

    PubMed

    Gómez-Gutiérrez, Claudia M; Luque, P A; Castro-Beltran, A; Vilchis-Nestor, A R; Lugo-Medina, Eder; Carrillo-Castillo, A; Quevedo-Lopez, M A; Olivas, A

    2015-01-01

    In this work, the influence of substrate on the morphology of ZnS thin films by chemical bath deposition is studied. The materials used were zinc acetate, tri-sodium citrate, thiourea, and ammonium hydroxide/ammonium chloride solution. The growth of ZnS thin films on different substrates showed a large variation on the surface, presenting a poor growth on SiO2 and HfO2 substrates. The thin films on ITO substrate presented a uniform and compact growth without pinholes. The optical properties showed a transmittance of about 85% in the visible range of 300-800 nm with band gap of 3.7 eV. © Wiley Periodicals, Inc.

  12. Atomic layer deposition of (K,Na)(Nb,Ta)O{sub 3} thin films

    SciTech Connect

    Sønsteby, Henrik Hovde Nilsen, Ola; Fjellvåg, Helmer

    2016-07-15

    Thin films of complex alkali oxides are frequently investigated due to the large range of electric effects that are found in this class of materials. Their piezo- and ferroelectric properties also place them as sustainable lead free alternatives in optoelectronic devices. Fully gas-based routes for deposition of such compounds are required for integration into microelectronic devices that need conformal thin films with high control of thickness- and composition. The authors here present a route for deposition of materials in the (K,Na)(Nb,Ta)O{sub 3}-system, including the four end members NaNbO{sub 3}, KNbO{sub 3}, NaTaO{sub 3}, and KTaO{sub 3}, using atomic layer deposition with emphasis on control of stoichiometry in such mixed quaternary and quinary compunds.

  13. Fabrication of InGaN thin-film transistors using pulsed sputtering deposition

    PubMed Central

    Itoh, Takeki; Kobayashi, Atsushi; Ueno, Kohei; Ohta, Jitsuo; Fujioka, Hiroshi

    2016-01-01

    We report the first demonstration of operational InGaN-based thin-film transistors (TFTs) on glass substrates. The key to our success was coating the glass substrate with a thin amorphous layer of HfO2, which enabled a highly c-axis-oriented growth of InGaN films using pulsed sputtering deposition. The electrical characteristics of the thin films were controlled easily by varying their In content. The optimized InGaN-TFTs exhibited a high on/off ratio of ~108, a field-effect mobility of ~22 cm2 V−1 s−1, and a maximum current density of ~30 mA/mm. These results lay the foundation for developing high-performance electronic devices on glass substrates using group III nitride semiconductors. PMID:27383148

  14. Excitation-dependent fluorescence from atomic/molecular layer deposited sodium-uracil thin films.

    PubMed

    Pale, Ville; Giedraityte, Zivile; Chen, Xi; Lopez-Acevedo, Olga; Tittonen, Ilkka; Karppinen, Maarit

    2017-08-01

    Atomic/molecular layer deposition (ALD/MLD) offers unique possibilities in the fabrication of inorganic-organic thin films with novel functionalities. Especially, incorporating nucleobases in the thin-film structures could open new avenues in the development of bio-electronic and photonic devices. Here we report an intense blue and widely excitation-dependent fluorescence in the visible region for ALD/MLD fabricated sodium-uracil thin films, where the crystalline network is formed from hydrogen-bonded uracil molecules linked via Na atoms. The excitation-dependent fluorescence is caused by the red-edge excitation shift (REES) effect taking place in the red-edge of the absorption spectrum, where the spectral relaxation occurs in continuous manner as demonstrated by the time-resolved measurements.

  15. Faraday effect of polycrystalline bismuth iron garnet thin film prepared by mist chemical vapor deposition method

    NASA Astrophysics Data System (ADS)

    Yao, Situ; Kamakura, Ryosuke; Murai, Shunsuke; Fujita, Koji; Tanaka, Katsuhisa

    2017-01-01

    We have synthesized polycrystalline thin film composed of a single phase of metastable bismuth iron garnet, Bi3Fe5O12, on a fused silica substrate, one of the most widely utilized substrates in the solid-state electronics, by using mist chemical vapor deposition (mist CVD) method. The phase purity and stoichiometry are confirmed by X-ray diffraction and Rutherford backscattering spectrometry. The resultant thin film shows a small surface roughness of 3.251 nm. The saturation magnetization at room temperature is 1200 G, and the Faraday rotation angle at 633 nm reaches -5.2 deg/μm. Both the magnetization and the Faraday rotation angles are somewhat higher than those of polycrystalline BIG thin films prepared by other methods.

  16. Fabrication of InGaN thin-film transistors using pulsed sputtering deposition

    NASA Astrophysics Data System (ADS)

    Itoh, Takeki; Kobayashi, Atsushi; Ueno, Kohei; Ohta, Jitsuo; Fujioka, Hiroshi

    2016-07-01

    We report the first demonstration of operational InGaN-based thin-film transistors (TFTs) on glass substrates. The key to our success was coating the glass substrate with a thin amorphous layer of HfO2, which enabled a highly c-axis-oriented growth of InGaN films using pulsed sputtering deposition. The electrical characteristics of the thin films were controlled easily by varying their In content. The optimized InGaN-TFTs exhibited a high on/off ratio of ~108, a field-effect mobility of ~22 cm2 V‑1 s‑1, and a maximum current density of ~30 mA/mm. These results lay the foundation for developing high-performance electronic devices on glass substrates using group III nitride semiconductors.

  17. Ti-Nb thin films deposited by magnetron sputtering on stainless steel

    SciTech Connect

    Gonzalez, E. David; Niemeyer, Terlize C.; Afonso, Conrado R. M.; Nascente, Pedro A. P.

    2016-03-15

    Thin films of Ti-Nb alloys were deposited on AISI 316L stainless steel substrate by magnetron sputtering, and the structure, composition, morphology, and microstructure of the films were analyzed by means of x-ray diffraction (XRD), (scanning) transmission electron microscopy (TEM) coupled with energy-dispersive x-ray spectroscopy, atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS). Thin films of four compositions were produced: Ti{sub 85}Nb{sub 15} (Ti-26 wt. % Nb), Ti{sub 80}Nb{sub 20} (Ti-33 wt. % Nb), Ti{sub 70}Nb{sub 30} (Ti-45 wt. % Nb), and Ti{sub 60}Nb{sub 40} (Ti-56 wt. % Nb). Structural characterization by XRD indicated that only the β phase was present in the thin films and that the increase in the Nb content modified the alloy film texture. These changes in the film texture, also detected by TEM analysis, were attributed to different growth modes related to the Nb content in the alloy films. The mean grain sizes measured by AFM increased with the Nb amount (from 197 to 222 nm). XPS analysis showed a predominance of oxidized Ti and Nb on the film surfaces and an enrichment of Ti.

  18. Synthesis and characterization of CrSe thin film produced via chemical bath deposition

    NASA Astrophysics Data System (ADS)

    kariper, Ishak afsin

    2017-02-01

    Chromium selenide (CrSe) crystalline thin film has been produced via chemical bath deposition on substrates (commercial glass). Transmittance, absorption, optical band gap and refractive index of the films have been examined by UV/VIS. Spectrum. Structural properties have been examined and XRD hexagonal form has been observed. The structural and optical properties of CrSe thin films, produced at different pH levels were analyzed; SEM and EDX analysis have been performed for surface analysis and elemental ratio of the films. It has been found that some properties of the films have been changed with pH and the changes of these properties with respect to pH have been investigated. Tested pH values were between 8 and 11. The optical band gap has been varied between 3.80 and 3.92 eV and film thickness has been changed from 76 nm to 126 nm for tested pH levels. Absorbance values were found to be 0.053, 0.018, 0.012 and 0.069 for pH values of 11, 10, 9 and 8, respectively (550 nm wavelength). The refractive index of CrSe thin films have been changed with film thickness, found as 2.27, 2.24, 2.25 and 2.26.

  19. Titanium oxide thin films obtained with physical and chemical vapour deposition methods for optical biosensing purposes.

    PubMed

    Dominik, M; Leśniewski, A; Janczuk, M; Niedziółka-Jönsson, J; Hołdyński, M; Wachnicki, Ł; Godlewski, M; Bock, W J; Śmietana, M

    2017-07-15

    This work discusses an application of titanium oxide (TiOx) thin films deposited using physical (reactive magnetron sputtering, RMS) and chemical (atomic layer deposition, ALD) vapour deposition methods as a functional coating for label-free optical biosensors. The films were applied as a coating for two types of sensors based on the localised surface plasmon resonance (LSPR) of gold nanoparticles deposited on a glass plate and on a long-period grating (LPG) induced in an optical fibre. Optical and structural properties of the TiOx thin films were investigated and discussed. It has been found that deposition method has a significant influence on optical properties and composition of the films, but negligible impact on TiOx surface silanization effectiveness. A higher content of oxygen with lower Ti content in the ALD films leads to the formation of layers with higher refractive index and slightly higher extinction coefficient than for the RMS TiOx. Moreover, application of the TiOx film independently on deposition method enables not only for tuning of the spectral response of the investigated biosensors, but also in case of LSPR for enhancing the ability for biofunctionalization, i.e., TiOx film mechanically protects the nanoparticles and induces change in the biofunctionalization procedure to the one typical for oxides. TiOx coated LSPR and LPG sensors with refractive index sensitivity of close to 30 and 3400nm/RIU, respectively, were investigated. The ability for molecular recognition was evaluated with the well-known complex formation between avidin and biotin as a model system. The shift in resonance wavelength reached 3 and 13.2nm in case of LSPR and LPG sensors, respectively. Any modification in TiOx properties resulting from the biofunctionalization process can be also clearly detected.

  20. Buffer layers for deposition of superconducting YBaCuO thin film on polycrystalline diamond

    NASA Astrophysics Data System (ADS)

    Beetz, Charles P.; Cui, G. J.; Lincoln, B. A.; Kirlin, Peter S.

    1992-09-01

    In an attempt to combine the properties of high temperature superconductors with the high thermal conductivity and low specific heat of diamond, we have explored the deposition of in- situ YBa(subscript 2)Cu(subscript 3)O(subscript 7-(delta) ) (YBCO) superconducting films on polycrystalline diamond thin films. We demonstrate for the first time superconducting YBCO films on diamond employing multiple layer buffer layer systems. Three different composite buffer layer systems were explored for this purpose: (1) Diamond/Zr/YSZ/YBCO, (2) Diamond/Si(subscript 3)N(subscript 4)/YSZ/YBCO, and (3) Diamond/SiO(subscript 2)/YSZ/YBCO. Adherent thin Zr films were deposited by dc sputtering on the diamond films at 450 to 820 degree(s)C. The yttria stabilized zirconia (YSZ) was deposited by reactive RF sputtering at 680 to 750 degree(s)C. The Si(subscript 3)N(subscript 4) and SiO(subscript 2) were also deposited by on-axis RF sputtering at 400 to 700 degree(s)C. YBCO films were grown on the buffer layers by off-axis RF sputtering at substrate temperatures between 690 degree(s)C and 750 degree(s)C. In all cases, the as-deposited YBCO films were superconducting above 77 K. This demonstration enables the fabrication of low heat capacity, fast response time bolometric far IR detectors and paves the way for the use of HTSC as a high frequency interconnect metallization on thick diamond film based multichip modules.

  1. Novel photoresist thin films with in-situ photoacid generator by molecular layer deposition

    NASA Astrophysics Data System (ADS)

    Zhou, Han; Bent, Stacey F.

    2013-03-01

    Current photoresist materials are facing many challenges introduced by advanced lithographies, particularly the need for excellent compositional homogeneity and ultrathin film thickness. Traditional spin-on polymeric resists have inherent limitations in achieving a high level of control over the chemical composition, leading to interest in development of alternative methods for making photoresists. In this work, we demonstrate that molecular layer deposition (MLD) is a potential method for synthesizing photoresists because it allows for precise control over organic film thickness and composition. MLD utilizes sequential, self-limiting reactions of organic precursors to build a thin film directly on a substrate surface and grows organic films by depositing only one molecular layer at each precursor dose, which in turn allows for fine-tuning of the position and concentration of various functionalities in the deposited film. In this study, we use bifunctional precursors, diamine and diisocyanate, to build polyurea resist films via urea coupling reaction between the amine and isocyanate groups. Acid-labile groups and photoacid generators (PAGs) are embedded in the backbone of the resist films with a highly uniform distribution. The resist films were successfully deposited and characterized for both materials properties and resist response. E-beam patterning was achieved with the resist films. Cross-linking behavior of the resist films was observed, likely due to the aromatic rings in the films, which is undesirable for application as a positive-tone photoresist. Moreover, the in-situ polymer-bound PAGs had low sensitivity. It is suggested that this effect may arise because the PAG is cation-bound, leading to lower efficiency of sulfur-carbon bond cleavage in the sulfonium cation, which is needed to produce the photoacid, and consequently a lower photoacid yield. Further work is needed to improve the performance of the MLD resist films.

  2. Optical properties of electrochemically deposited ZnO thin films on colloidal crystal film of SiO2 microspheres.

    PubMed

    Oh, Yong Taeg; Choi, Bum Ho; Shin, Dong Chan

    2012-02-01

    The optical properties of electrochemically deposited ZnO thin films on colloidal crystal film of SiO2 microspheres structures were studied. Colloidal crystal film of SiO2 microspheres were self-assembled by evaporation using SiO2 in solution at a constant 0.1 wt%. ZnO in thin films was then electrochemically deposited on to colloidal crystal film of SiO2 microspheres. During electrochemical deposition, the content of Zn(NO3)2 x 6H2O in solution was 5 wt%, and the process's conditions were varied between of 2-4 V and 30-120 s at room temperature, with subsequent heat-treatment between 200 and 400 degrees C. A smooth surface and uniform thickness of 1.8 microm were obtained at 3 V for 90 s. The highest PL peak intensity was obtained in the ZnO thin film heat-treated at 400 degrees C. The double layered ZnO/SiO2 colloidal crystals showed clearly better emission properties than the SiO2/ZnO and ZnO structures.

  3. Deposition of ceramic thin films from aqueous solutions at low temperatures

    NASA Astrophysics Data System (ADS)

    Zhang, Guangneng

    Ceramic thin films have received substantial interest and found numerous applications. A novel ceramic thin films deposition technique has been developed and studied systematically. This technique employs controlled hydrolysis of inorganic salt as precursor from aqueous solutions at low temperature. It starts with the nucleation followed by growth of the particles. The nucleation can take place through homogeneous or heterogeneous nucleation. One of the determining parameters seems to the degree of supersaturation, which is the thermodynamic driving force for nucleation. In light of this, our work first focused on the definition and calculation of degree of supersaturation, and our experiments then indicated the role of degree of supersaturation in nucleation and growth and further deposition processes. We found that homogeneous nucleation is prevalence when degree of supersaturation is high enough, while heterogeneous nucleation can play a more important role when degree of supersaturation is low enough. The growing film can avoid lattice strain between different microstructures. It seems that the preference toward either of the two mechanisms results in distinct film microstructures and morphologies. This diversity introduced two more research areas, one in modeling of intermolecular forces, and the other in film properties. Specifically, we have studied the deposition of ZrO2, TiO 2, and SnO2 thin films on various substrates including bare Si and self-assembled monolayer (SAM)-coated Si substrates. We found that all the films can be deposited on both substrates. In addition, we found the TiO2 films display a large variety of morphologies, from very dense particulate structure to dendritic structure, due to different degrees of supersaturation. From classic nucleation theory and experiments, we determined the interfacial energy and critical nuclei diameter for nucleation of TiO 2 to be 0.072 J·m-2 and typically 0.5 nm, respectively. We developed a quantitative

  4. Electrochromism in sputter deposited W1-y MoyO3 thin films

    NASA Astrophysics Data System (ADS)

    Arvizu, M. A.; Granqvist, C. G.; Niklasson, G. A.

    2016-02-01

    Electrochromic (EC) properties of tungsten-molybdenum oxide (W1-y MoyO3) thin films were investigated. The films were deposited on indium tin oxide covered glass by reactive DC sputtering from tungsten and molybdenum targets. Elemental compositions of the W1-y MoyO3 films were determined by Rutherford back scattering. Voltammetric cycling was performed in an electrolyte of 1 M LiClO4 in propylene carbonate. An increase in molybdenum content in the EC films caused both a shift towards higher energies and a lowering of the maximum of the optical absorption band, as compared with WO3 EC films. Durability under electrochemical cycling was diminished for W1-y MoyO3 EC films.

  5. Dielectric dilatometry on thin Teflon-PTFE films prepared by pulsed-laser deposition

    NASA Astrophysics Data System (ADS)

    Schwoediauer, Reinhard; Bauer-Gogonea, Simona; Bauer, Stefan; Heitz, J.; Arenholz, Enno; Baeuerle, Dieter

    1999-12-01

    Polytetrafluoroethylene (Teflon PTFE) films were grown by pulsed-laser deposition (PLD). Films prepared by ablation from press-sintered targets are found to be highly crystalline, with spherulite sizes adjustable over more than one order in magnitude by suitable thermal annealing. As revealed by dielectric dilatometry, PLD-PTFE films show characteristics remarkably similar to those of conventional PTFE, i.e. the same structural first-order phase transitions. Dielectric losses are low and indicate no tendency to film oxidation. PLD-PTFE films additionally show an excellent charge-stability, comparable and even superior to commercially available Teflon-PTFE foils. PLD-PTFE enlarges the family of Teflon materials and may thus become interesting for potential miniaturized electret devices. Furthermore, dielectric dilatometry provides an elegant means for the determination of the coefficient of thermal expansion in thin nonpolar films.

  6. Aerosol-Assisted Chemical Vapor Deposited Thin Films for Space Photovoltaics

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; McNatt, Jeremiah; Dickman, John E.; Jin, Michael H.-C.; Banger, Kulbinder K.; Kelly, Christopher V.; AquinoGonzalez, Angel R.; Rockett, Angus A.

    2006-01-01

    Copper indium disulfide thin films were deposited via aerosol-assisted chemical vapor deposition using single source precursors. Processing and post-processing parameters were varied in order to modify morphology, stoichiometry, crystallography, electrical properties, and optical properties in order to optimize device-quality material. Growth at atmospheric pressure in a horizontal hot-wall reactor at 395 C yielded best device films. Placing the susceptor closer to the evaporation zone and flowing a more precursor-rich carrier gas through the reactor yielded shinier, smoother, denser-looking films. Growth of (112)-oriented films yielded more Cu-rich films with fewer secondary phases than growth of (204)/(220)-oriented films. Post-deposition sulfur-vapor annealing enhanced stoichiometry and crystallinity of the films. Photoluminescence studies revealed four major emission bands (1.45, 1.43, 1.37, and 1.32 eV) and a broad band associated with deep defects. The highest device efficiency for an aerosol-assisted chemical vapor deposited cell was 1.03 percent.

  7. Dysprosium oxide and dysprosium-oxide-doped titanium oxide thin films grown by atomic layer deposition

    SciTech Connect

    Tamm, Aile Kozlova, Jekaterina; Aarik, Lauri; Aarik, Jaan; Kukli, Kaupo; Link, Joosep; Stern, Raivo

    2015-01-15

    Dysprosium oxide and dysprosium-oxide-doped titanium oxide thin films were grown by atomic layer deposition on silicon substrates. For depositing dysprosium and titanium oxides Dy(thd){sub 3}-O{sub 3} and TiCl{sub 4}-O{sub 3} were used as precursors combinations. Appropriate parameters for Dy(thd){sub 3}-O{sub 3} growth process were obtained by using a quartz crystal microbalance system. The Dy{sub 2}O{sub 3} films were deposited on planar substrates and on three-dimensional substrates with aspect ratio 1:20. The Dy/Ti ratio of Dy{sub 2}O{sub 3}-doped TiO{sub 2} films deposited on a planar silicon substrate ranged from 0.04 to 0.06. Magnetometry studies revealed that saturation of magnetization could not be observed in planar Dy{sub 2}O{sub 3} films, but it was observable in Dy{sub 2}O{sub 3} films on 3D substrates and in doped TiO{sub 2} films with a Dy/Ti atomic ratio of 0.06. The latter films exhibited saturation magnetization 10{sup −6} A cm{sup 2} and coercivity 11 kA/m at room temperature.

  8. Annealing effect on structural and optical properties of chemical bath deposited MnS thin film

    SciTech Connect

    Ulutas, Cemal; Gumus, Cebrail

    2016-03-25

    MnS thin film was prepared by the chemical bath deposition (CBD) method on commercial microscope glass substrate deposited at 30 °C. The as-deposited film was given thermal annealing treatment in air atmosphere at various temperatures (150, 300 and 450 °C) for 1 h. The MnS thin film was characterized by using X-ray diffraction (XRD), UV-vis spectrophotometer and Hall effect measurement system. The effect of annealing temperature on the structural, electrical and optical properties such as optical constants of refractive index (n) and energy band gap (E{sub g}) of the film was determined. XRD measurements reveal that the film is crystallized in the wurtzite phase and changed to tetragonal Mn{sub 3}O{sub 4} phase after being annealed at 300 °C. The energy band gap of film decreased from 3.69 eV to 3.21 eV based on the annealing temperature.

  9. High-temperature conductivity in chemical bath deposited copper selenide thin films

    NASA Astrophysics Data System (ADS)

    Dhanam, M.; Manoj, P. K.; Prabhu, Rajeev. R.

    2005-07-01

    This paper reports high-temperature (305-523 K) electrical studies of chemical bath deposited copper (I) selenide (Cu 2-xSe) and copper (II) selenide (Cu 3Se 2) thin films. Cu 2-xSe and Cu 3Se 2 have been prepared on glass substrates from the same chemical bath at room temperature by controlling the pH. From X-ray diffraction (XRD) profiles, it has been found that Cu 2-xSe and Cu 3Se 2 have cubic and tetragonal structures, respectively. The composition of the chemical constituent in the films has been confirmed from XRD data and energy-dispersive X-ray analysis (EDAX). It has been found that both phases of copper selenide thin films have thermally activated conduction in the high-temperature range. In this paper we also report the variation of electrical parameters with film thickness and the applied voltage.

  10. Highly crystalline MoS{sub 2} thin films grown by pulsed laser deposition

    SciTech Connect

    Serrao, Claudy R.; You, Long; Gadgil, Sushant; Hu, Chenming; Salahuddin, Sayeef; Diamond, Anthony M.; Hsu, Shang-Lin; Clarkson, James; Carraro, Carlo; Maboudian, Roya

    2015-02-02

    Highly crystalline thin films of MoS{sub 2} were prepared over large area by pulsed laser deposition down to a single monolayer on Al{sub 2}O{sub 3} (0001), GaN (0001), and SiC-6H (0001) substrates. X-ray diffraction and selected area electron diffraction studies show that the films are quasi-epitaxial with good out-of-plane texture. In addition, the thin films were observed to be highly crystalline with rocking curve full width half maxima of 0.01°, smooth with a RMS roughness of 0.27 nm, and uniform in thickness based on Raman spectroscopy. From transport measurements, the as-grown films were found to be p-type.

  11. Growth of γ-alumina thin films by pulsed laser deposition and plasma diagnostic

    NASA Astrophysics Data System (ADS)

    Yahiaoui, K.; Abdelli-Messaci, S.; Messaoud Aberkane, S.; Siad, M.; Kellou, A.

    2017-07-01

    The present work discusses about the synthesis of alumina thin films, which have applications in current and next-generation solid-state electronic devices due to their attractive properties. Alumina thin films were synthesized by pulsed laser deposition at different oxygen pressures and substrate temperatures. The dependence of substrate temperature, oxygen pressure, and the deposition time on the properties of the films has been observed by growing three series of alumina thin films on Si (100). The first films are synthesized using substrate temperatures ranging from room temperature to 780 °C at 0.01 mbar of O2. The second series was realized at a fixed substrate temperature of 760 °C and varied oxygen pressure (from 0.005 to 0.05 mbar). The third set of series was elaborated at different deposition times (from 15 to 60 min) while the oxygen pressure and the substrate temperature were fixed at 0.01 mbar and 760 °C, respectively. The films were characterized using X-ray diffractometer (XRD) for structural analysis, a scanning electron microscope for morphological analysis, a nano-indenter for mechanical analysis (hardness and Young's modulus), and Rutherford backscattering spectroscopy for thickness and stoichiometry measurements. Using optical emission spectroscopy, plasma diagnostic was carried out both in the vacuum and in the presence of oxygen with a pressure ranging from 0.01 to 0.05 mbar. Several neutral, ionic, and molecular species were identified such as Al, Al+, and Al++ in vacuum and in oxygen ambiance, O and AlO molecular bands in oxygen-ambient atmosphere. The spatiotemporal evolution of the most relevant species was achieved and their velocities were estimated. The highest amount of crystallized alumina in γ-phase was found in the films elaborated under 0.01 mbar of O2, at a substrate temperature of 780 °C, and a deposition time of 60 min.

  12. Deposition and characterization of silicon thin-films by aluminum-induced crystallization

    NASA Astrophysics Data System (ADS)

    Ebil, Ozgenc

    Polycrystalline silicon (poly-Si) as a thin-film solar cell material could have major advantages compared to non-silicon thin-film technologies. In theory, thin-film poly-Si may retain the performance and stability of c-Si while taking advantage of established manufacturing techniques. However, poly-Si films deposited onto foreign substrates at low temperatures typically have an average grain size of 10--50 nm. Such a grain structure presents a potential problem for device performance since it introduces an excessive number of grain boundaries which, if left unpassivated, lead to poor solar cell properties. Therefore, for optimum device performance, the grain size of the poly-Si film should be at least comparable to the thickness of the films. For this project, the objectives were the deposition of poly-Si thin-films with 2--5 mum grain size on glass substrates using in-situ and conventional aluminum-induced crystallization (AIC) and the development of a model for AIC process. In-situ AIC experiments were performed using Hot-Wire Chemical Vapor Deposition (HWCVD) both above and below the eutectic temperature (577°C) of Si-Al binary system. Conventional AIC experiments were performed using a-Si layers deposited on aluminum coated glass substrates by Electron-beam deposition, Plasma Enhanced Chemical Vapor Deposition (PECVD) and HWCVD. Continuous poly-Si films with an average grain size of 10 mum on glass substrates were achieved by both in-situ and conventional aluminum-induced crystallization of Si below eutectic temperature. The grain size was determined by three factors; the grain structure of Al layer, the nature of the interfacial oxide, and crystallization temperature. The interface oxide was found to be crucial for AIC process but not necessary for crystallization itself. The characterization of interfacial oxide layer formed on Al films revealed a bilayer structure containing Al2O3 and Al(OH)3 . The effective activation energy for AIC process was determined

  13. Some aspects over the quality of thin films deposited on special steels used in hydraulic blades

    NASA Astrophysics Data System (ADS)

    Tugui, C. A.; Vizureanu, P.; Iftimie, N.; Steigmann, R.

    2016-08-01

    The experimental research involved in this paper consists in the obtaining of superior physical, chemical and mechanical properties of stainless steels used in the construction of hydraulic turbine blades. These properties are obtained by deposition of hard thin films in order to improve the wear resistance, increasing the hardness but maintaining the tenacious core of the material. The chosen methods for deposition are electrospark deposition because it has relatively low costs, are easy to obtain, the layers have a good adherence to support and the thickness can be variable in function of the established conditions and the pulsed laser deposition because high quality films can be obtained at nanometric precision. The samples will be prepared for the analysis of the structure using optical method as well as for the obtaining of the optimal roughness for the deposition. The physical, chemical and mechanical properties will be determined after deposition using SEM and EDX, in order to emphasize the structure film-substrate and repartition of the deposition elements on the surface and in transversal section. The non-destructive testing has emphasized the good adherence between deposited layer and the metallic support, due to double deposition, spallation regions doesn't appear.

  14. V2O5 thin film deposition for application in organic solar cells

    NASA Astrophysics Data System (ADS)

    Arbab, Elhadi A. A.; Mola, Genene Tessema

    2016-04-01

    Vanadium pentoxide V2O5 films were fabricated by way of electrochemical deposition technique for application as hole transport buffer layer in organic solar cell. A thin and uniform V2O5 films were successfully deposited on indium tin oxide-coated glass substrate. The characterization of surface morphology and optical properties of the deposition suggest that the films are suitable for photovoltaic application. Organic solar cell fabricated using V2O5 as hole transport buffer layer showed better devices performance and environmental stability than those devices fabricated with PEDOT:PSS. In an ambient device preparation condition, the power conversion efficiency increases by nearly 80 % compared with PEDOT:PSS-based devices. The devices lifetime using V2O5 buffer layer has improved by a factor of 10 over those devices with PEDOT:PSS.

  15. Characterization of CuInTe2 thin films deposited by electrochemical technique

    NASA Astrophysics Data System (ADS)

    Patil, Neelima A.; Lakhe, Manorama; Chaure, N. B.

    2012-06-01

    Copper Indium ditelluride (CuInTe2) thin films were deposited onto fluorine doped tin oxide (FTO) coated glass substrates by electrodeposition technique. Cyclic voltammetry analysis was used to optimize suitable deposition parameters. Micro structural properties were examined by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDAX) for as-deposited and annealed films at 400 °C. After annealing the prominent (112), (220/204), (312/116) peaks of CuInTe2 (CIT) were observed indicate tetragonal structure which is most common structure of I-III-VI2 semiconductors, suitable for high efficiency photovoltaic devices. The band gap of the CIT film was determined around 1.01 eV. Elemental composition analysis was performed using energy dispersive X-ray analysis (EDAX).

  16. Effect of deposition times on structure of Ga-doped ZnO thin films as humidity sensor

    SciTech Connect

    Khalid, Faridzatul Shahira; Awang, Rozidawati

    2014-09-03

    Gallium doped zinc oxide (GZO) has good electrical property. It is widely used as transparent electrode in photovoltaic devices, and sensing element in gas and pressure sensors. GZO thin film was prepared using magnetron sputtering. Film deposition times were set at 10, 15, 20, 25 and 30 minutes to get samples of different thickness. X-ray diffraction (XRD) was used to determine the structure of GZO thin films. Structure for GZO thin film is hexagonal wurtzite structure. Morphology and thickness of GZO thin films was observed from FESEM micrographs. Grain size and thickness of thin films improved with increasing deposition times. However, increasing the thickness of thin films occur below 25 minutes only. Electrical properties of GZO thin films were studied using a four-point probe technique. The changes in the structure of the thin films lead to the changed of their electrical properties resulting in the reduction of the film resistance. These thin films properties significantly implying the potential application of the sample as a humidity sensor.

  17. Characterization of physically vapor deposited AF2400 thin films

    SciTech Connect

    Chow, R.; Spragge, M.K.; Loomis, G.E.; Rainer, F.; Ward, R.; Thomas, I.M.; Kozlowski, M.R.

    1993-11-01

    Anti-reflective coatings made with Teflon AF2400 had the highest damage thresholds recorded for physical vapor deposited coatings at the Lawrence Livermore National Laboratory damage facility. Physical vapor deposited layers of Teflon AF2400, a perfluorinated amorphous polymer, maintained the bulk optical properties of a high transmittance from 200 nm to 1600 nm, and a low refractive index. In addition, the refractive index can be intentionally reduced by control of two common deposition parameters, deposition rate and 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. The coatings adhered to fused silica and silicon wafers under normal laboratory handling conditions.

  18. Properties of nanostructured undoped ZrO{sub 2} thin film electrolytes by plasma enhanced atomic layer deposition for thin film solid oxide fuel cells

    SciTech Connect

    Cho, Gu Young; Noh, Seungtak; Lee, Yoon Ho; Cha, Suk Won E-mail: swcha@snu.ac.kr; Ji, Sanghoon; Hong, Soon Wook; Koo, Bongjun; Kim, Young-Beom E-mail: swcha@snu.ac.kr; An, Jihwan

    2016-01-15

    Nanostructured ZrO{sub 2} thin films were prepared by thermal atomic layer deposition (ALD) and by plasma-enhanced atomic layer deposition (PEALD). The effects of the deposition conditions of temperature, reactant, plasma power, and duration upon the physical and chemical properties of ZrO{sub 2} films were investigated. The ZrO{sub 2} films by PEALD were polycrystalline and had low contamination, rough surfaces, and relatively large grains. Increasing the plasma power and duration led to a clear polycrystalline structure with relatively large grains due to the additional energy imparted by the plasma. After characterization, the films were incorporated as electrolytes in thin film solid oxide fuel cells, and the performance was measured at 500 °C. Despite similar structure and cathode morphology of the cells studied, the thin film solid oxide fuel cell with the ZrO{sub 2} thin film electrolyte by the thermal ALD at 250 °C exhibited the highest power density (38 mW/cm{sup 2}) because of the lowest average grain size at cathode/electrolyte interface.

  19. Effect of target density on the growth and properties of YGBCO thin films deposited by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Liu, Linfei; Li, Yiejie; Wu, Xiang; Yao, Yanjie; Wang, Menglin; Wang, Binbin

    2016-12-01

    Some works found that target density had not a large effects on the superconducting or structural properties of YBa2Cu3O7-δ (YBCO) films prepared by pulsed laser deposition. However, the possible effect of target density on the Y0.5Gd0.5Ba2Cu3O7-δ (YGBCO) is not clear. In this paper, YGBCO thin films were deposited on flexible metal substrates by pulsed laser deposition using target with different densities. The density of each YGBCO target was varied from to 4.0 g/cm3 to 5.5 g/cm3. The aim of this study was to determine the relationship between the microstructure and superconducting properties of YGBCO films as a function of the target density. The film structures were examined by X-ray diffraction and field emission scanning electron microscopy. The superconducting properties of the YGBCO films were evaluated using the conventional four-probe method and PPMS. It was found that all the YGBCO films had pure c-axis orientation. The target density had effect on the surface morphology and superconducting properties of the YGBCO thin films. With increasing target density, the pore became larger and the distribution density and size of the particles became higher and larger, and the critical current Ic decreased. The YGBCO film deposited at a target density of 4.0 g/cm3 exhibited the highest critical current density Jc of 5.4 MA/cm2 at 77 K and self-field, 47.2 MA/cm2 at 0 T and 8.8 MA/cm2 at 9 T at 4.2 K and B//c.

  20. Design of Faraday cup ion detectors built by thin film deposition

    NASA Astrophysics Data System (ADS)

    Szalkowski, G. A.; Darrow, D. S.; Cecil, F. E.

    2017-03-01

    Thin film Faraday cup detectors can provide measurements of fast ion loss from magnetically confined fusion plasmas. These multilayer detectors can resolve the energy distribution of the lost ions in addition to giving the total loss rate. Prior detectors were assembled from discrete foils and insulating sheets. Outlined here is a design methodology for creating detectors using thin film deposition that are suited to particular scientific goals. The intention is to use detectors created by this method on the Joint European Torus (JET) and the National Spherical Torus Experiment-Upgrade (NSTX-U). The detectors will consist of alternating layers of aluminum and silicon dioxide, with layer thicknesses chosen to isolate energies of interest. Thin film deposition offers the advantage of relatively simple and more mechanically robust construction compared to other methods, as well as allowing precise control of film thickness. Furthermore, this depositional fabrication technique places the layers in intimate thermal contact, providing for three-dimensional conduction and dissipation of the ion-produced heating in the layers, rather than the essentially two-dimensional heat conduction in the discrete foil stack implementation.

  1. Structures and Properties of C-Doped NiCr Thin Film Deposited by Closed-Field Unbalanced Magnetron Sputtering

    NASA Astrophysics Data System (ADS)

    Lai, Lifei; Wang, Jinxia; Wang, Hongtao; Bao, Mingdong

    2017-01-01

    The structures and properties of C-doped NiCr thin film as embedded thin film resistor (ETFR) materials were studied by closed-field, unbalanced magnetron sputtering method. The C-doped NiCr (NiCrC1) thin film had more stable electrical performance, better corrosion resistance, and higher hardness than NiCr thin film. The temperature coefficient of resistance (TCR) of NiCrC1 thin film deposited at room temperature (from 19.73 ppm/K to 173.7 ppm/K) was lower than that of NiCr thin film (from 157.8 ppm/K to 378.9 ppm/K), and the sheet resistor (154.25 Ω/Sq) was higher than that of NiCr thin film (62.84 Ω/Sq). The preferred orientations of C-doped NiCr thin film was Ni (111), while that of NiCr thin film was Ni (011). The carbon-doped NiCr thin film can reduce the defects and stress and change the preferred orientations. The dominant carbon in C-doped NiCr thin film had a graphite-like structure.

  2. Study of deposition parameters for the fabrication of ZnO thin films using femtosecond laser

    NASA Astrophysics Data System (ADS)

    Hashmi, Jaweria Zartaj; Siraj, Khurram; Latif, Anwar; Murray, Mathew; Jose, Gin

    2016-08-01

    Femtosecond (fs) pulsed laser deposition (fs-PLD) of ZnO thin film on borosilicate glass substrates is reported in this work. The effect of important fs-PLD parameters such as target-substrate distance, laser pulse energy and substrate temperature on structure, morphology, optical transparency and luminescence of as-deposited films is discussed. XRD analysis reveals that all the films grown using the laser energy range 120-230 μJ are polycrystalline when they are deposited at room temperature in a ~10-5 Torr vacuum. Introducing 0.7 mTorr oxygen pressure, the films show preferred c-axis growth and transform into a single-crystal-like film when the substrate temperature is increased to 100 °C. The scanning electron micrographs show the presence of small nano-size grains at 25 °C, which grow in size to the regular hexagonal shape particles at 100 °C. Optical transmission of the ZnO film is found to increase with an increase in crystal quality. Maximum transmittance of 95 % in the wavelength range 400-1400 nm is achieved for films deposited at 100 °C employing a laser pulse energy of 180 μJ. The luminescence spectra show a strong UV emission band peaked at 377 nm close to the ZnO band gap. The shallow donor defects increase at higher pulse energies and higher substrate temperatures, which give rise to violet-blue luminescence. The results indicate that nano-crystalline ZnO thin films with high crystalline quality and optical transparency can be fabricated by using pulses from fs lasers.

  3. [Spectrum diagnostics for optimization of experimental parameters in thin films deposited by magnetron sputtering].

    PubMed

    Guo, Qing-Lin; Cui, Yong-Liang; Chen, Jian-Hui; Zhang, Jin-Ping; Huai, Su-Fang; Liu, Bao-Ting; Chen, Jin-Zhong

    2010-12-01

    The plasma emission spectra generated during the deposition process of Si-based thin films by radio frequency (RF) magnetron sputtering using Cu and Al targets in an argon atmosphere were acquired by the plasma analysis system, which consists of a magnetron sputtering apparatus, an Omni-lambda300 series grating spectrometer, a CCD data acquisition system and an optical fiber transmission system. The variation in Cu and Al plasma emission spectra intensity depending on sputtering conditions, such as sputtering time, sputtering power, the target-to-substrate distance and deposition pressure, was studied by using the analysis lines Cu I 324. 754 nm, Cu I 327. 396 nm, Cu I 333. 784 nm, Cu I 353. 039 nm, Al I 394. 403 nm and Al I 396. 153 nm. Compared with the option of experimental parameters of thin films deposited by RF magnetron sputtering, it was shown that emission spectra analysis methods play a guiding role in optimizing the deposition conditions of thin films in RF magnetron sputtering.

  4. Ultrasonic Spray-Assisted Solution-Based Vapor-Deposition of Aluminum Tris(8-hydroxyquinoline) Thin Films

    NASA Astrophysics Data System (ADS)

    Piao, Jinchun; Katori, Shigetaka; Ikenoue, Takumi; Fujita, Shizuo

    2011-02-01

    Aluminum tris(8-hydroxyquinoline) (Alq3) thin films were fabricated by a vapor-deposition technique from its methanol solution, that is, by the ultrasonic-assisted mist deposition technique. The application of high ultrasonic power to the Alq3-methanol mixture resulted in a stable and transparent solution. Mist particles formed by ultrasonic atomization of the solution were used as the source for vapor-deposition at the substrate temperature of 100-200 °C. Optical absorption and photoluminescence characteristics indicated the formation of Alq3 thin films. The results promise the formation of thin films of a variety of organic materials by the solution-based technique.

  5. Preparation and characterization of ALD deposited ZnO thin films studied for gas sensors

    NASA Astrophysics Data System (ADS)

    Boyadjiev, S. I.; Georgieva, V.; Yordanov, R.; Raicheva, Z.; Szilágyi, I. M.

    2016-11-01

    Applying atomic layer deposition (ALD), very thin zinc oxide (ZnO) films were deposited on quartz resonators, and their gas sensing properties were studied using the quartz crystal microbalance (QCM) method. The gas sensing of the ZnO films to NO2 was tested in the concentration interval between 10 and 5000 ppm. On the basis of registered frequency change of the QCM, for each concentration the sorbed mass was calculated. Further characterization of the films was carried out by various techniques, i.e. by SEM-EDS, XRD, ellipsometry, and FTIR spectroscopy. Although being very thin, the films were gas sensitive to NO2 already at room temperature and could register very well as low concentrations as 100 ppm, while the sorption was fully reversible. Our results for very thin ALD ZnO films show that the described fast, simple and cost-effective technology could be implemented for producing gas sensors working at room temperature and being capable to detect in real time low concentrations of NO2.

  6. Plasma enhanced chemical vapor deposition of ZrO2 thin films

    SciTech Connect

    Saravanan, Kolandaivelu

    1993-12-09

    Amorphous ZrO2 thin films were deposited in an inductively coupled PECVD system using a Zr β-diketonate, Zr(C11H19O2)4, as the precursor. The deposits were air annealed at 900C for 5 min to get pure, single phase, oriented, polycrystalline α-ZrO2. Feasibility of using 2 different types of reactors was investigated. The inductively heated horizontal reactor depositions at 600C had a lower deposition rate and the films were non-uniform in thickness with a columnar structure. The resistively heated vertical reactor depositions at 350C had a higher deposition rate and the films were more uniform in thickness with a fine grained microstructure. The statistical design was demonstrated as an effective technique to analyze the effect of process conditions on the rate of deposition and relative (h00) orientation. The factorial design was used to quantify the two responses in terms of the process variables and their mutual interactions. The statistical design for rate of deposition was found to correlate with the trends observed in classical design.

  7. Chemically deposited thin films of sulfides and selenides of antimony and bismuth as solar energy materials

    NASA Astrophysics Data System (ADS)

    Nair, M. T.; Nair, Padmanabhan K.; Garcia, V. M.; Pena, Y.; Arenas, O. L.; Garcia, J. C.; Gomez-Daza, O.

    1997-10-01

    Chemical bath deposition techniques for bismuth sulfide, bismuth selenide, antimony sulfide, and antimony selenide thin films of about 0.20 - 0.25 micrometer thickness are reported. All these materials may be considered as solar absorber films: strong optical absorption edges, with absorption coefficient, (alpha) , greater than 104 cm-1, are located at 1.31 eV for Bi2Se3, 1.33 eV for Bi2S3, 1.8 eV for Sb2S3, and 1.35 eV for Sb2Se3. As deposited, all the films are nearly amorphous. However, well defined crystalline peaks matching bismuthinite (JCPDS 17- 0320), paraguanajuatite (JCPDS 33-0214), and stibnite (JCPDS 6-0474) and antimony selenide (JCPDS 15-0861) for Bi2S3, Bi2Se3, Sb2S3 and Sb2Se3 respectively, are observed when the films are annealed in nitrogen at 300 degrees Celsius. This is accompanied by a substantial modification of the electrical conductivity in the films: from 10-7 (Omega) -1 cm-1 (in as prepared films) to 10 (Omega) -1 cm-1 in the case of bismuth sulfide and selenide films, and enhancement of photosensitivity in the case of antimony sulfide films. The chemical deposition of a CuS/CuxSe film on these Vx- VIy films and subsequent annealing at 300 degrees Celsius for 1 h at 1 torr of nitrogen leads to the formation of p-type films (conductivity of 1 - 100 (Omega) -1 cm-1) of multinary composition. Among these, the formation of Cu3BiS3 (JCPDS 9-0488) and Cu3SbS4 (JCPDS 35- 0581), CuSbS2 (JCPDS 35-0413) have been clearly detected. Solar energy applications of these films are suggested.

  8. Chemical vapor deposition of metal diboride and metal oxide thin films from borohydride-bonded precursors

    NASA Astrophysics Data System (ADS)

    Yang, Yu

    Metal borohydrides denotes the type of metal complex in which the metals are connected to the surrounding ligands through boron-hydrogen bridge bonds. They are excellent CVD precursors owning to their outstanding volatility and high reactivity. Transition metal diboride and metal oxide thin films suitable for various technological applications are deposited from these novel precursors. In this dissertation, comprehensive investigations of thin film growth rate, composition, and properties as a function of precursor pressure and substrate temperature were carried out for the CVD of HfB2 and MgO. It is determined that their CVD growth kinetics can be well explained with a Langmuir surface reaction mechanism. A structure zone model is proposed to explain the microstructure-process relationship of the CVD thin films in general. In future generations of microelectronics fabrication, materials need to be deposited into recess features with smaller dimensions and higher aspect ratios. A new approach is developed to obtain super-conformal coating (bottom-up filling) of such high aspect ratio features. The super-conformal growth is demonstrated in the CVD of CrB2 and HfB2 films from the corresponding borohydride precursors with atomic and molecular growth suppressors. Computer simulation is employed to understand the mechanism of the super-conformal deposition. The high Tc superconductor MgB2 were deposited at low temperatures (T = 300°C--400°C) from a recently developed highly volatile borohydride-bonded Mg precursor, by means of catalyst-enhanced chemical vapor deposition. The films are stoichiometric and highly crystallized, however, the lattice constants shift away from the MgB2 structure to the diboride structure of the catalyst metal, suggesting that Mg is partially substituted by the corresponding metals.

  9. Control of Thin Liquid Film Morphology During Solvent-Assisted Film Deposition

    SciTech Connect

    Evmenenko, G.; Stripe, B; Dutta, P

    2010-01-01

    Liquid films of different silicate esters were deposited from volatile solvents on hydroxylated and hydrogen-passivated silicon surfaces. We show that adsorption of silicate ester molecules and the resulting structural morphology of the liquid films not only are determined by attractive van der Waals forces with contributions from electrostatic interactions between the silicone ester moieties and oxide surface sites but also can be tuned by modifying the substrate surface or by changing the liquid-solvent interactions. Our results also show the importance of the conformational properties of liquid molecules and their rearrangements at the liquid/solid interface for controlled solvent-assisted film deposition.

  10. Room temperature deposition of ZnSe thin films by successive ionic layer adsorption and reaction (SILAR) method

    SciTech Connect

    Kale, R.B.; Lokhande, C.D. . E-mail: rb_kale@yahoo.co.in

    2004-10-04

    The zinc selenide (ZnSe) thin films are deposited onto glass substrate using relatively simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method. The films are deposited using zinc acetate sodium selenosulphate precursors. The concentration, pH, immersion and rinsing times and number of immersion cycles have been optimized to obtain good quality ZnSe thin films. The X-ray diffraction (XRD) study and scanning electron microscopy (SEM) studies reveals nanocrystalline nature alongwith some amorphous phase present in ZnSe thin films. Energy dispersive X-ray (EDAX) analysis shows that the films are Se deficient. From optical absorption data, the optical band gap 'E{sub g}' for as-deposited thin film was found to be 2.8 eV and electrical resistivity in the order of 10{sup 7} {omega} cm.

  11. Phase-Field Models for Simulating Physical Vapor Deposition and Microstructure Evolution of Thin Films

    NASA Astrophysics Data System (ADS)

    Stewart, James A., Jr.

    The focus of this research is to develop, implement, and utilize phase-field models to study microstructure evolution in thin films during physical vapor deposition (PVD). There are four main goals to this dissertation. First, a phase-field model is developed to simulate PVD of a single-phase polycrystalline material by coupling previous modeling efforts on deposition of single-phase materials and grain evolution in polycrystalline materials. Second, a phase-field model is developed to simulate PVD of a polymorphic material by coupling previous modeling efforts on PVD of a single-phase material, evolution in multiphase materials, and phase nucleation. Third, a novel free energy functional is proposed that incorporates appropriate energetics and dynamics for simultaneous modeling of PVD and grain evolution in single-phase polycrystalline materials. Finally, these phase-field models are implemented into custom simulation codes and utilized to illustrate these models' capabilities in capturing PVD thin film growth, grain and grain boundary (GB) evolution, phase evolution and nucleation, and temperature evolution. In general, these simulations show: grain coarsening through grain rotation and GB migration such that grains tend to align with the thin film surface features and GBs migrate to locations between these features so that each surface feature has a distinct grain and orientation; the incident vapor flux rate controls the density of the thin film and the formation of surface and subsurface features; the substrate phase distribution initially acts as a template for the growing microstructure until the thin film becomes sufficiently thick; latent heat released during PVD increases the surface temperature of the thin film creating a temperature gradient within the thin film influencing phase evolution and nucleation; and temperature distributions lead to regions within the thin film that allow for multiple phases to be stable and coexist. Further, this work shows

  12. In situ stress evolution during and after sputter deposition of Al thin films.

    PubMed

    Pletea, M; Koch, R; Wendrock, H; Kaltofen, R; Schmidt, O G

    2009-06-03

    The stress, growth, and morphology evolution of Al thin films up to 300 nm thick, sputter deposited at a constant rate of 0.04 nm s(-1) onto thermally oxidized Si(100) substrates have been investigated for various sputter pressures in the range from 0.05 to 6 Pa. The stress evolution has been studied during and after the film deposition by means of in situ substrate curvature measurements using an optical two-beam deflection method. In order to obtain insight into the mechanisms of stress generation and relaxation, the microstructure of the films was investigated by scanning electron microscopy, focused-ion-beam microscopy, and atomic force microscopy. The stress evolution during the early stage of deposition of films is consistent with the Volmer-Weber growth mode known for metals with high adatom mobility. For thicker films, the compressive stress increases in the sputter pressure range of 0.05-0.5 Pa, whereas at even higher sputter pressures a transition from compressive to tensile stress takes place. This transition is correlated with a change from a relatively dense to a more porous microstructure characterized by decreasing mass density and increasing electrical resistivity with increasing sputter pressure. The dependence of the stress and microstructure on the sputter pressure can be consistently understood through a combination of the stress mechanisms for vapor and sputter deposited films proposed in the literature.

  13. Non-conventional photocathodes based on Cu thin films deposited on Y substrate by sputtering

    NASA Astrophysics Data System (ADS)

    Perrone, A.; D'Elia, M.; Gontad, F.; Di Giulio, M.; Maruccio, G.; Cola, A.; Stankova, N. E.; Kovacheva, D. G.; Broitman, E.

    2014-07-01

    Copper (Cu) thin films were deposited on yttrium (Y) substrate by sputtering. During the deposition, a small central area of the Y substrate was shielded to avoid the film deposition and was successively used to study its photoemissive properties. This configuration has two advantages: the cathode presents (i) the quantum efficiency and the work function of Y and (ii) high electrical compatibility when inserted into the conventional radio-frequency gun built with Cu bulk. The photocathode was investigated by scanning electron microscopy to determine surface morphology. X-ray diffraction and atomic force microscopy studies were performed to compare the structure and surface properties of the deposited film. The measured electrical resistivity value of the Cu film was similar to that of high purity Cu bulk. Film to substrate adhesion was also evaluated using the Daimler-Benz Rockwell-C adhesion test method. Finally, the photoelectron performance in terms of quantum efficiency was obtained in a high vacuum photodiode cell before and after laser cleaning procedures. A comparison with the results obtained with a twin sample prepared by pulsed laser deposition is presented and discussed.

  14. Influence of solution deposition rate on properties of V2O5 thin films deposited by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Abd-Alghafour, N. M.; Ahmed, Naser M.; Hassan, Zai; Mohammad, Sabah M.

    2016-07-01

    Vanadium oxide (V2O5) thin films were deposited on glass substrates by using a cost-efficient spray pyrolysis technique. The films were grown at 350° through thermal decomposition of VCl3 in deionized water with different solution spray rates. The high resolution X-ray diffraction results revealed the formation of nanocrystalline films having orthorhombic structures with preferential orientation along (101) direction. The spray rate influenced the surface morphology and crystallite size of the films. The crystallite size was found to increase whereas the micro-strain was decreased by increasing the spray deposition rates. The increase in crystallite size and decrease in the macrostrain resulted in an improvement in the films' crystallinity. The UV-Visible spectroscopy analysis indicated that the average transmittance of all films lies in the range 75-80 %. The band gap of V2O5 film was decreased from 2.65 to 2.46 eV with increase of the spray deposition rate from 5 ml/min to 10 ml/min. first, second, and third level headings (first level heading).

  15. Mechanical properties of thin silicon films deposited at low temperatures by PECVD

    NASA Astrophysics Data System (ADS)

    Gaspar, J.; Paul, O.; Chu, V.; Conde, J. P.

    2010-03-01

    This paper presents elastic and fracture properties of hydrogenated amorphous and nanocrystalline silicon thin films and correlates them with optoelectronic and structural properties of the films. Properties are extracted from the load-deflection response of membranes and include the plane-strain modulus, residual stress and failure stress. Bilayer diaphragms made of hydrogenated amorphous and nanocrystalline silicon films obtained by plasma-enhanced chemical vapor deposition onto a reference silicon nitride layer are fabricated and characterized. A comprehensive study of the mechanical properties of these silicon thin films is presented as a function of the substrate temperature and hydrogen dilution used during deposition. The extracted plane-strain modulus, 118.5 ± 3.0 GPa, is insensitive to deposition conditions, in strong contrast to the residual stress, with values between -738 and 188 MPa. The tensile and compressive stress components in the silicon films, evaluated at membrane failure, increase from 0.11 to 0.96 GPa and from -3.40 to -2.25 GPa, respectively, with increasing residual stress.

  16. Incorporation of Linear Spacer Molecules in Vapor Deposited Silicone Polymer Thin Films

    PubMed Central

    Achyuta, Anil Kumar H.; White, Aleksandr J.; Pryce Lewis, Hilton G.; Murthy, Shashi K.

    2009-01-01

    Poly (trivinyl-trimethyl-cyclotrisiloxane) or polyV3D3 is a promising insulating thin film known for its potential application in neural probe fabrication. However, its time-consuming synthesis rate renders it impractical for manufacturing standards. Previously, the growth mechanism of polyV3D3 was shown to be affected by significant steric barriers. This article describes the synthesis of a copolymer of polyV3D3 via initiated chemical vapor deposition (iCVD) using V3D3 as the monomer, hexavinyl disiloxane (HVDS) as a spacer, and tert-butyl peroxide (TBP) as the initiator to obtain nearly a 4-fold increase in deposition rate. The film formation kinetics is limited by the adsorption of the reactive species on the surface of the substrate with an activation energy of −41.5 kJ/mol with respect to substrate temperature. The films deposited are insoluble in polar and non polar solvents due to their extremely crosslinked structure. They have excellent adhesion to silicon substrates and their adhesion properties are retained after soaking in a variety of solvents. Spectroscopic evidence shows that the films do not vary in structure after boiling in DI water for 1 hour, illustrating hydrolytic stability. PolyV3D3-HVDS has a bulk resistivity of 5.6 (±1) × 1014 Ω-cm, which is comparable to that of parylene-C; the insulating thin film currently used in neuroprosthetic devices. PMID:21359171

  17. Adherent and Conformal Zn(S,O,OH) Thin Films by Rapid Chemical Bath Deposition with Hexamethylenetetramine Additive.

    PubMed

    Opasanont, Borirak; Van, Khoa T; Kuba, Austin G; Choudhury, Kaushik Roy; Baxter, Jason B

    2015-06-03

    ZnS is a wide band gap semiconductor whose many applications, such as photovoltaic buffer layers, require uniform and continuous films down to several nanometers thick. Chemical bath deposition (CBD) is a simple, low-cost, and scalable technique to deposit such inorganic films. However, previous attempts at CBD of ZnS have often resulted in nodular noncontinuous films, slow growth rates at low pH, and high ratio of oxygen impurities at high pH. In this work, ZnS thin films were grown by adding hexamethylenetetramine (HMTA) to a conventional recipe that uses zinc sulfate, nitrilotriacetic acid trisodium salt, and thioacetamide. Dynamic bath characterization showed that HMTA helps the bath to maintain near-neutral pH and also acts as a catalyst, which leads to fast nucleation and deposition rates, continuous films, and less oxygen impurities in the films. Films deposited on glass from HMTA-containing bath were uniform, continuous, and 90 nm thick after 1 h, as opposed to films grown without HMTA that were ∼3 times thinner and more nodular. On Cu2(Zn,Sn)Se4, films grown with HMTA were continuous within 10 min. The films have comparatively few oxygen impurities, with S/(S+O) atomic ratio of 88%, and high optical transmission of 98% at 360 nm. The Zn(S,O,OH) films exhibit excellent adhesion to glass and high resistivity, which make them ideal nucleation layers for other metal sulfides. Their promise as a nucleation layer was demonstrated with the deposition of thin, continuous Sb2S3 overlayers. This novel HMTA chemistry enables rapid deposition of Zn(S,O,OH) thin films to serve as a nucleation layer, a photovoltaic buffer layer, or an extremely thin continuous coating for thin film applications. HMTA may also be applied in a similar manner for solution deposition of other metal chalcogenide and oxide thin films with superior properties.

  18. Texture and Magnetocrystalline Anisotropy in NiFe2O 4 Thin films Deposited via Chemical Solution Deposition

    NASA Astrophysics Data System (ADS)

    Seifikar, Safoura

    Spinel nickel ferrite with the chemical formula Fe3+[Ni 2+Fe3+]O4 (NFO) has attracted highly attentions for many applications due to its room temperature magnetic behavior, moderate electrical resistivity and, high Curie temperature. Along with other magnetic spinel cubic ferrites including CoFe2O4 and MnFe 2O4, NFO has long been considered as the magnetostrictive phase to fabricate magnetoelectric (ME) composites. One of the approaches to improve the ME response of the composites is to enhance the magnetostriction of the magnetic phase by texturing along its magnetic easy axis direction. In this work, spinel cubic NiFe2O4 (NFO) thin films are derived via chemical solution deposition (CSD) technique. The films grown on Si substrates show a granular microstructure and surface roughness of 3 nm. The effects of varying the processing condition including pyrolysis and annealing temperature have been studied on the microstructure and the resulting magnetic properties. Microstructural studies confirm the formation of randomly oriented, phase-pure spinel nickel ferrite on Si substrates. It is shown that the pyrolysis temperature does not affect the microstructure and resulting magnetic properties, while increased the grain size as a results of increased annealing temperature influences the magnetic properties. Magnetoelectric thin film multilayers are prepared also using NFO as the magnetostrictive phase and PbZr0.52Ti0.48O 3 (PZT) as the piezoelectric phase via CSD. The PZT/NFO composite microstructures are investigated through TEM and SEM studies and the interface is engineered to minimize the elemental interdiffusion between phases and the substrate. The dielectric property of the piezoelectric phase and the magnetic response of the magnetic phase are investigated. The addition of a Pt intermediate layer resulted in an improved dielectric properties obtained in Si/NFO/Pt/PZT composite configuration. To improve the magnetostriction response of the NFO layer, same CSD

  19. Periodic oxidation for fabricating titanium oxynitride thin films via atomic layer deposition

    SciTech Connect

    Iwashita, Shinya Aoyama, Shintaro; Nasu, Masayuki; Shimomura, Kouji; Noro, Naotaka; Hasegawa, Toshio; Akasaka, Yasushi; Miyashita, Kohei

    2016-01-15

    This paper demonstrates thermal atomic layer deposition (ALD) combined with periodic oxidation for synthesizing titanium oxynitride (TiON) thin films. The process used a typical ALD reactor for the synthesis of titanium nitride (TiN) films wherein oxygen was supplied periodically between the ALD-TiN cycles. The great advantage of the process proposed here was that it allowed the TiN films to be oxidized efficiently. Also, a uniform depth profile of the oxygen concentration in the films could be obtained by tuning the oxidation conditions, allowing the process to produce a wide variety of TiON films. The resistivity measurement is a convenient method to confirm the reproducibility of metal film fabrication but may not be applicable for TiON films depending upon the oxidation condition because the films can easily turn into insulators when subjected to periodic oxidation. Therefore, an alternative reproducibility confirmation method was required. In this study, spectroscopic ellipsometry was applied to monitor the variation of TiON films and was able to detect changes in film structures such as conductor–insulator transitions in the TiON films.

  20. Zirconium doped TiO2 thin films deposited by chemical spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Juma, A.; Oja Acik, I.; Oluwabi, A. T.; Mere, A.; Mikli, V.; Danilson, M.; Krunks, M.

    2016-11-01

    Chemical spray pyrolysis (CSP) is a flexible deposition technique that allows for mixing of the precursor solutions in different proportions suitable for doping thin films. The CSP method was used to dope TiO2 thin films with Zr by adding zirconium(IV) acetylacetonate into a solution of titanium(IV) isopropoxide in ethanol stabilized by acetylacetone at [Zr]/[Ti] of 0, 5, 10 and 20 at%. The Zr-doped TiO2 thin films were uniform and homogeneous showing much smaller grains than the undoped TiO2 films. Zr stabilized the anatase phase to temperatures above 800 °C depending on Zr concentration in the spray solution. The concentration of Zr determined by XPS was 6.4 at% for the thin film deposited from the 20 at% solution. According to AFM studies, Zr doping decreased the root mean square roughness of TiO2 film from 5.9 to 1.1 nm. An XRD study of samples with the highest Zr amount showed the ZrTiO4 phase started forming after annealing at 800 °C. The optical band gap for TiO2 decreased from 3.3 eV to 3.0 eV after annealing at 800 °C but for the TiO2:Zr(20) film it remained at 3.4 eV. The dielectric constant increased by more than four times with Zr-doping and this was associated with the change in the bond formations caused by substitution of Ti by Zr in the lattice.

  1. Deposition of oxide thin films on silicon using organic self-assembled monolayers

    NASA Astrophysics Data System (ADS)

    DeGuire, Mark R.; Shin, Hyunjung; Collins, R. J.; Agarwal, Monika; Sukenik, Chaim N.; Heuer, Arthur H.

    1996-03-01

    Crystalline oxide thin films have been synthesized at low temperatures from aqueous liquid solutions. A key element of the approach is the use of organic self-assembled monolayers (SAMs) on the substrate to promote the growth of adherent inorganic films. A SAM is a close- packed, highly ordered array of long-chain hydrocarbon molecules, anchored to the substrate by covalent bonds. The terminating functional group on the SAM surface is chosen so as to initiate and help sustain the formation of the oxide film when the substrate is immersed in the oxide precursor solution. Synthesis, microstructural characterization, and properties of TiO2, ZrO2, SiO2, and Y2O3 films are surveyed. Crystalline films were formed either directly from solution, or through subsequent heat treatments at temperatures that in most cases were lower than typical sol-gel or vapor phase deposition processes. All depositions were from aqueous solutions onto single-crystal (100) silicon. The ability to produce patterned films on a micron scale has been demonstrated, taking advantage of the selective deposition characteristics towards different surface functional groups of the SAM. The role of the SAM in oxide film formation is discussed.

  2. Phase control of iridium and iridium oxide thin films in atomic layer deposition

    SciTech Connect

    Kim, Sung-Wook; Kwon, Se-Hun; Kwak, Dong-Kee; Kang, Sang-Won

    2008-01-15

    The atomic layer deposition of iridium (Ir) and iridium oxide (IrO{sub 2}) films was investigated using an alternating supply of (ethylcyclopentadienyl)(1,5-cyclooctadiene) iridium and oxygen gas at temperatures between 230 and 290 deg. C. The phase transition between Ir and IrO{sub 2} occurred at the critical oxygen partial pressure during the oxygen injection pulse. The oxygen partial pressure was controlled by the O{sub 2}/(Ar+O{sub 2}) ratio or deposition pressures. The resistivity of the deposited Ir and IrO{sub 2} films was about 9 and 120 {mu}{omega} cm, respectively. In addition, the critical oxygen partial pressure for the phase transition between Ir and IrO{sub 2} was increased with increasing the deposition temperature. Thus, the phase of the deposited film, either Ir or IrO{sub 2}, was controlled by the oxygen partial pressure and the deposition temperature. However, the formation of a thin Ir layer was detected between the IrO{sub 2} and SiO{sub 2} substrate. To remove this interfacial layer, the oxygen partial pressure is increased to a severe condition. And the impurity contents were below the detection limit of Auger electron spectroscopy in both Ir and IrO{sub 2} films.

  3. Microstructural and conductivity changes induced by annealing of ZnO:B thin films deposited by chemical vapour deposition.

    PubMed

    David, C; Girardeau, T; Paumier, F; Eyidi, D; Lacroix, B; Papathanasiou, N; Tinkham, B P; Guérin, P; Marteau, M

    2011-08-24

    Zinc oxide (ZnO) thin films have attracted much attention in recent years due to progress in crystal growth for a large variety of technological applications including optoelectronics and transparent electrodes in solar cells. Boron (B)-doped ZnO thin films are deposited by low pressure chemical vapour deposition (LPCVD) on Si(100). These films exhibit a strong (002) texture with a pyramidal grain structure. The ZnO films were annealed after growth; the annealing temperature and the atmosphere appear to strongly impact the layer conductivity. This work will first present the modification of the physical properties (carrier concentration, mobility) extracted from the simulation of layer reflection in the infrared range. At low annealing temperatures the mobility increases slightly before decreasing drastically above a temperature close to 250 °C. The chemical and structural evolution (XPS, x-ray diffraction) of the films was also studied to identify the relationship between microstructural modifications and the variations observed in the film conductivity. An in situ XRD study during annealing has been performed under air and low pressure conditions. As observed for electrical properties, the microstructural modifications shift to higher temperatures for vacuum annealing.

  4. Pulsed Laser Deposition of High Tc Superconducting Thin Films

    DTIC Science & Technology

    1992-04-15

    de- temperature thermal detectors such as the pyroelectric ec sign of imaging arrays of high-T, bolometers for wave- tector, the thermopile , or the... concepts to discuss materials and fabrication considerations. The thermal con- the sensitivity of imaging arrays of high-T, bolometers as a ductance G to...any conceived IR detector . In addition, flux motion studies have been made by this group using our films of YBCO grown on 0.003" thick silicon wafers

  5. Superconducting niobium titanium nitride thin films deposited by plasma-enhanced atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Yemane, Y. T.; Sowa, M. J.; Zhang, J.; Ju, L.; Deguns, E. W.; Strandwitz, N. C.; Prinz, F. B.; Provine, J.

    2017-09-01

    NbTiN has a variety of superconducting applications, ranging from RF cavities to single-photon detectors. Here, we systematically investigated the plasma-enhanced atomic layer deposition (PEALD) of Nb x Ti{}1-x{{N}} with the organometallic precursors (t-butylimido) tris(diethyamido) niobium(V) and tetrakis (dimethylamido) titanium in conjunction with a remote H2/N2 plasma. Deposited film properties have been studied as a function of the ratio of Nb to Ti precursor pulses within each ALD supercycle. PEALD NbTiN films were characterized with spectroscopic ellipsometry (thickness, optical properties), four point probe (resistivity), x-ray photoelectron spectroscopy (composition), x-ray reflectivity (density and thickness), x-ray diffraction (crystallinity), and superconductivity measurements. The PEALD process has shown distinct advantages over deposition of superconducting films via thermal ALD or sputtering, for example a lower processing temperature and more efficient control of film composition. This control of film composition enabled the tuning of electrical and superconducting properties, such as varying the superconducting critical temperature T C between 6.9 and 13.2 K.

  6. Chemical spray pyrolysis of β-In2S3 thin films deposited at different temperatures

    NASA Astrophysics Data System (ADS)

    Sall, Thierno; Marí Soucase, Bernabé; Mollar, Miguel; Hartitti, Bouchaib; Fahoume, Mounir

    2015-01-01

    In2S3 thin films were deposited onto indium tin oxide-coated glass substrates by chemical spray pyrolysis while keeping the substrates at different temperatures. The structures of the sprayed In2S3 thin films were characterized by X-ray diffraction (XFD). The quality of the thin films was determined by Raman spectroscopy. Scanning electron microscopy (SEM) and atomic force microscopy were used to explore the surface morphology and topography of the thin films, respectively. The optical band gap was determined based on optical transmission measurements. The indium sulfide phase exhibited a preferential orientation in the (0, 0, 12) crystallographic direction according to the XRD analysis. The phonon vibration modes determined by Raman spectroscopy also confirmed the presence of the In2S3 phase in our samples. According to SEM, the surface morphologies of the films were free of defects. The optical band gap energy varied from 2.82 eV to 2.95 eV.

  7. Effect of polyvinyl alcohol on electrochemically deposited ZnO thin films for DSSC applications

    NASA Astrophysics Data System (ADS)

    Marimuthu, T.; Anandhan, N.

    2017-05-01

    Nanostructures of zinc oxide (ZnO) thin film are electrochemically deposited in the absence and presence of polyvinyl alcohol (PVA) on fluorine doped tin oxide (FTO) substrate. X-ray diffraction (XRD) patterns and Raman spectroscopy confirmed the formation of hexagonal structure of ZnO. The film prepared in the presence of PVA showed a better crystallinity and its crystalline growth along the (002) plane orientation. Field emission scanning electron microscope (FE-SEM) images display nanowire arrays (NWAs) and sponge like morphology for films prepared in the absence and presence of PVA, respectively. Photoluminescence (PL) spectra depict the film prepared in the presence PVA having less atomic defects with good crystal quality compared with other film. Dye sensitized solar cell (DSSC) is constructed using low cost eosin yellow dye and current-voltage (J-V) curve is recorded for optimized sponge like morphology based solar cell.

  8. Improved efficiency of the chemical bath deposition method during growth of ZnO thin films

    SciTech Connect

    Ortega-Lopez, Mauricio; Avila-Garcia, Alejandro; Albor-Aguilera, M.L.; Resendiz, V.M. Sanchez

    2003-06-19

    Chemical bath deposition (CBD) is an inexpensive and low temperature method (25-90 deg. C) that allows to deposit large area semiconductor thin films. However, the extent of the desired heterogeneous reaction upon the substrate surface is limited first by the competing homogeneous reaction, which is responsible for colloidal particles formation in the bulk solution, and second, by the material deposition on the CBD reactor walls. Therefore, the CBD method exhibits low efficiency in terms of profiting the whole amount of starting materials. The present work describes a procedure to deposit ZnO thin films by CBD in an efficient way, since it offers the possibility to minimize both the undesirable homogeneous reaction in the bulk solution and the material deposition on the CBD reactor walls. In a first stage, zinc peroxide (ZnO{sub 2}) crystallizing with cubic structure is obtained. This compound shows a good average transparency (90%) and an optical bandgap of 4.2 eV. After an annealing process, the ZnO{sub 2} suffers a transformation toward polycrystalline ZnO with hexagonal structure and 3.25 eV of optical bandgap. The surface morphology of the films, analyzed by atomic force microscope (AFM), reveals three-dimensional growth features as well as no colloidal particles upon the surface, therefore indicating the predominance of the heterogeneous reaction during the growth.

  9. Photocatalytic property of titanium dioxide thin films deposited by radio frequency magnetron sputtering in argon and water vapour plasma

    NASA Astrophysics Data System (ADS)

    Sirghi, L.; Hatanaka, Y.; Sakaguchi, K.

    2015-10-01

    The present work is investigating the photocatalytic activity of TiO2 thin films deposited by radiofrequency magnetron sputtering of a pure TiO2 target in Ar and Ar/H2O (pressure ratio 40/3) plasmas. Optical absorption, structure, surface morphology and chemical structure of the deposited films were comparatively studied. The films were amorphous and included a large amount of hydroxyl groups (about 5% of oxygen atoms were bounded to hydrogen) irrespective of the intentional content of water in the deposition chamber. Incorporation of hydroxyl groups in the film deposited in pure Ar plasma is explained as contamination of the working gas with water molecules desorbed by plasma from the deposition chamber walls. However, intentional input of water vapour into the discharge chamber decreased the deposition speed and roughness of the deposited films. The good photocatalytic activity of the deposited films could be attributed hydroxyl groups in their structures.

  10. Cell adhesion to cathodic arc plasma deposited CrAlSiN thin films

    NASA Astrophysics Data System (ADS)

    Kim, Sun Kyu; Pham, Vuong-Hung; Kim, Chong-Hyun

    2012-07-01

    Osteoblast cell response (cell adhesion, actin cytoskeleton and focal contact adhesion as well as cell proliferation) to CrN, CrAlSiN and Ti thin films was evaluated in vitro. Cell adhesion and actin stress fibers organization depended on the film composition significantly. Immunofluorescent staining of vinculin in osteoblast cells showed good focal contact adhesion on the CrAlSiN and Ti thin films but not on the CrN thin films. Cell proliferation was significantly greater on the CrAlSiN thin films as well as on Ti thin films than on the CrN thin films.

  11. Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared photosensing

    NASA Astrophysics Data System (ADS)

    Xu, Jixian; Sutherland, Brandon R.; Hoogland, Sjoerd; Fan, Fengjia; Kinge, Sachin; Sargent, Edward H.

    2015-10-01

    Atomic layer deposition (ALD), prized for its high-quality thin-film formation in the absence of high temperature or high vacuum, has become an industry standard for the large-area deposition of a wide array of oxide materials. Recently, it has shown promise in the formation of nanocrystalline sulfide films. Here, we demonstrate the viability of ALD lead sulfide for photodetection. Leveraging the conformal capabilities of ALD, we enhance the absorption without compromising the extraction efficiency in the absorbing layer by utilizing a ZnO nanowire electrode. The nanowires are first coated with a thin shunt-preventing TiO2 layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10-2 A W-1 and a shot-derived specific detectivity of 3 × 109 Jones at 1530 nm wavelength.

  12. MAPLE deposition of Mn(III) metalloporphyrin thin films: Structural, topographical and electrochemical investigations

    NASA Astrophysics Data System (ADS)

    Cristescu, R.; Popescu, C.; Popescu, A. C.; Grigorescu, S.; Mihailescu, I. N.; Ciucu, A. A.; Iordache, S.; Andronie, A.; Stamatin, I.; Fagadar-Cosma, E.; Chrisey, D. B.

    2011-04-01

    We report the deposition by MAPLE of metallized nanostructured (5,10,15,20-tetraphenyl)porphinato manganese(III) chloride thin films onto gold screen-printed electrodes, or <1 1 1> Si substrates. The deposited nanostructures were characterized by atomic force microscopy and exhibited globular structures with average diameters decreasing with laser fluence. Raman spectroscopy showed that no major decomposition appeared. We have investigated the Mn(III)-metalloporphyrin thin films by cyclic voltammetry in order to evaluate the potential bio/chemosensing activity on dopamine neurotransmitter analyte. We have found that the manganese(III)-porphyrin is appropriate as a single mediator for dopamine sensing in the specific case of gold screen-printed electrodes.

  13. Industrial Application of Thin Films (TiAl)N Deposited on Thermo-Wells

    SciTech Connect

    Velez, G.; Jaramillo, S.; Arango, Y. C.; Devia, D.; Quintero, J.; Devia, A.

    2006-12-04

    The thermo-well is formed by two layers, one layer is a ceramic and the other layer is anviloy (comprised tungsten). They are used to coat the thermocouple in the control temperature system during the Aluminum-Silicon alloy melting process. After two weeks of continuous work at 750 deg. C of temperature (the alloy temperature), a high wear in this material is observed, affecting the ceramic. (TiAl)N thin films are deposited directly on the anviloy substrates by the PAPVD (Plasma Assisted Physics Vapor Deposition) in arc pulsed technique, using a TiAl target in a mono-vaporizer system, composed by a reactor and a power controlled system. Two opposite electrodes are placed into the reactor and discharge is produced by a controlled power system. The XRD (X-ray diffraction) patterns show the presence of the (TiAl)N thin film peaks. The morphological characteristics are studied by the scanning probe microscopy (SPM)

  14. Method for controlling energy density for reliable pulsed laser deposition of thin films

    SciTech Connect

    Dowden, P. C. E-mail: qxjia@lanl.gov; Bi, Z.; Jia, Q. X. E-mail: qxjia@lanl.gov

    2014-02-15

    We have established a methodology to stabilize the laser energy density on a target surface in pulsed laser deposition of thin films. To control the focused laser spot on a target, we have imaged a defined aperture in the beamline (so called image-focus) instead of focusing the beam on a target based on a simple “lens-focus.” To control the laser energy density on a target, we have introduced a continuously variable attenuator between the output of the laser and the imaged aperture to manipulate the energy to a desired level by running the laser in a “constant voltage” mode to eliminate changes in the lasers’ beam dimensions. This methodology leads to much better controllability/reproducibility for reliable pulsed laser deposition of high performance electronic thin films.

  15. Magnetic domain observation of FeCo thin films fabricated by alternate monoatomic layer deposition

    SciTech Connect

    Ohtsuki, T. Kotsugi, M.; Ohkochi, T.; Kojima, T.; Mizuguchi, M.; Takanashi, K.

    2014-01-28

    FeCo thin films are fabricated by alternate monoatomic layer deposition method on a Cu{sub 3}Au buffer layer, which in-plane lattice constant is very close to the predicted value to obtain a large magnetic anisotropy constant. The variation of the in-plane lattice constant during the deposition process is investigated by reflection high-energy electron diffraction. The magnetic domain images are also observed by a photoelectron emission microscope in order to microscopically understand the magnetic structure. As a result, element-specific magnetic domain images show that Fe and Co magnetic moments align parallel. A series of images obtained with various azimuth reveal that the FeCo thin films show fourfold in-plane magnetic anisotropy along 〈110〉 direction, and that the magnetic domain structure is composed only of 90∘ wall.

  16. Enhanced Photocatalytic Performance Depending on Morphology of Bismuth Vanadate Thin Film Synthesized by Pulsed Laser Deposition.

    PubMed

    Jeong, Sang Yun; Choi, Kyoung Soon; Shin, Hye-Min; Kim, Taemin Ludvic; Song, Jaesun; Yoon, Sejun; Jang, Ho Won; Yoon, Myung-Han; Jeon, Cheolho; Lee, Jouhahn; Lee, Sanghan

    2017-01-11

    We have fabricated high quality bismuth vanadate (BiVO4) polycrystalline thin films as photoanodes by pulsed laser deposition (PLD) without a postannealing process. The structure of the grown films is the photocatalytically active phase of scheelite-monoclinic BiVO4 which was obtained by X-ray diffraction (XRD) analysis. The change of surface morphology for the BIVO4 thin films depending on growth temperature during synthesis has been observed by scanning electron microscopy (SEM), and its influence on water splitting performance was investigated. The current density of the BiVO4 film grown on a glass substrate covered with fluorine-doped tin oxide (FTO) at 230 °C was as high as 3.0 mA/cm(2) at 1.23 V versus the potential of the reversible hydrogen electrode (VRHE) under AM 1.5G illumination, which is the highest value so far in previously reported BiVO4 films grown by physical vapor deposition (PVD) methods. We expect that doping of transition metal or decoration of oxygen evolution catalyst (OEC) in our BiVO4 film might further enhance the performance.

  17. Preparation and characterization of LiCoO2 thin films by laser ablation deposition

    NASA Astrophysics Data System (ADS)

    Antaya, M.; Dahn, J. R.; Preston, J. S.; Rossen, E.; Reimers, J. N.

    1993-03-01

    Thin films of LiCoO2 are obtained by laser ablation from sintered LiCoO2 targets. The films were deposited on stainless steel or tantalum foil substrates so they could be used as cathodes in rechargeable thin-film lithium batteries. The films are amorphous when deposited on unheated substrates but crystallize readily when heated in air above 500 C. Using X-ray diffraction, we show that the films are basically stoichiometric and have no impurity phases present. They consist partly of the normal bulk LiCoO2 phase which can be prepared by reacting Li2CO3 and CoCO3 at 850 C. However, the films also contain some of the new, low temperature LiCoO2 phase. We have synthesized bulk low temperature LiCoO2 from LiNO3 and CO(NO3)2 at 400 C to measure its structure and electrochemical properties. Electrochemical measurements can distinguish between the high and low temperature phases.

  18. Random lasing of ZnO thin films grown by pulsed-laser deposition

    NASA Astrophysics Data System (ADS)

    Cachoncinlle, C.; Hebert, C.; Perrière, J.; Nistor, M.; Petit, A.; Millon, E.

    2015-05-01

    Low-dimensional semiconductor structures on nanometer scale are of great interest because of their strong potential applications in nanotechnologies. We report here optical and structural properties on UV lasing in ZnO thin films. The ZnO films, 110 nm thick, were prepared using pulsed-laser deposition on c-cut sapphire substrates at 500 °C under 10-2 oxygen pressure. The ZnO films are nearly stoichiometric, dense and display the wurtzite phase. The films are highly textured along the ZnO c-axis and are constituted of nanocrystallites. According to Hall measurements these films are conductive (0.11 Ω cm). Photoluminescence measurements reveals a so-called random lasing in the range 390 to 410 nm, when illuminating at 355 nm with a tripled frequency pulsed Nd-YAG laser. Such random lasing is obtained at rather low optical pumping, 45 kW cm-2, a value lower than those classically reported for pulsed-laser deposition thin films.

  19. Biocompatible Mn2+-doped carbonated hydroxyapatite thin films grown by pulsed laser deposition.

    PubMed

    György, E; Toricelli, P; Socol, G; Iliescu, M; Mayer, I; Mihailescu, I N; Bigi, A; Werckman, J

    2004-11-01

    Mn(2+)-doped carbonated hydroxyapatite (Mn-CHA) thin films were obtained by pulsed laser deposition on Ti substrates. The results of the performed complementary diagnostic techniques, X-ray diffraction, infrared spectroscopy, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy investigations indicate that the films are crystalline with a Ca/P ratio of about 1.64-1.66. The optimum conditions, when nearly stoichiometric crystalline thin films were deposited, were found to be 10 Pa oxygen pressure, 400 degrees C substrate temperature, and postdeposition heat treatment in water vapors at the same substrate temperature. The films were seeded with L929 fibroblast and hFOB1.19 osteoblast cells and subjected to in vitro tests. Both fibroblast and osteoblast cells have a good adherence on the Mn-CHA film and on the Ti or polystyrene references. Proliferation and viability tests showed that osteoblast cells growth on Mn-CHA-coated Ti was enhanced as compared to uncoated pure Ti surfaces. Caspase-1 activity was not affected significantly by the material, showing that Mn-CHA does not induce apoptosis of cultured cells. These results demonstrate that Mn-CHA films on Ti should provoke a faster osteointegration of the coated implants as compared to pure Ti. (c) 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 353-358, 2004.

  20. Superconducting Properties of Htsc Thin Films Prepared in Situ by Single Target Deposition

    NASA Astrophysics Data System (ADS)

    Geerk, J.; Xi, X. X.; Li, H. C.; Guan, W. Y.; Kus, P.; Höbel, M.; Linker, G.; Meyer, O.; Ratzel, F.; Schultheiss, C.; Smithey, R.; Strehlau, B.; Weschenfelder, F.

    Thin films of ReBaCuO (Re=Y, Gd) and of BiCaSrCuO have been deposited onto A12O3, MgO, SrTiO3, Si and ZrO2 substrates by planar and inverted cylindrical magnetron sputtering. The main advantage of this preparation technique is the high reproducibility allowing detailed and systematic studies of the film properties as a function of deposition parameters. Optimum deposition parameters were a high oxygen partial pressure of 2×10-1 Torr in an oxygen-argon mixture and substrate temperatures near 800°C. Except for the substrate Si the films grow highly textured on all substrates. For the 1-2-3 material zero resistance is obtained near 90 K for the case of textured growth. For Si the best film showed zero resistance near 84 K. High critical currents between 4×105 and 5.5×106 A/cm2 were determined for films of the 1-2-3 material on the substrates MgO, ZrO2 and SrTiO3. On films SrTio3 tunnel junctions with Pb and In counterelectrodes could be prepared which showed a gap-like feature in their current-voltage characteristic. These junctions could be prepared with great reproducibility and experimental arguments could be provided which show that this gap-like feature is due to a superconducting density of states effect. Finally, first results are presented on YBaCuO thin films which were deposited by a novel ablation device which uses a pulsed electron beam instead of the laser beam.