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Sample records for ceo2 thin films

  1. Optical properties of CeO2 thin films

    Indian Academy of Sciences (India)

    S Debnath; M R Islam; M S R Khan

    2007-08-01

    Cerium oxide (CeO2) thin films have been prepared by electron beam evaporation technique onto glass substrate at a pressure of about 6 × 10-6 Torr. The thickness of CeO2 films ranges from 140–180 nm. The optical properties of cerium oxide films are studied in the wavelength range of 200–850 nm. The film is highly transparent in the visible region. It is also observed that the film has low reflectance in the ultra-violet region. The optical band gap of the film is determined and is found to decrease with the increase of film thickness. The values of absorption coefficient, extinction coefficient, refractive index, dielectric constant, phase angle and loss angle have been calculated from the optical measurements. The X-ray diffraction of the film showed that the film is crystalline in nature. The crystallite size of CeO2 films have been evaluated and found to be small. The experimental -values of the film agreed closely with the standard values.

  2. Violet/blue photoluminescence from CeO2 thin film

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    CeO2 thin film was fabricated by dual ion beam epitaxial technique. The violet/blue PL at room temperature and lower temperature was observed from the CeO2 thin film. After the analysis of crystal structure and valence in the compound was carried out by the XRD and XPS technique, it was inferred that the origin of CeO2 PL was due to the electrons transition from Ce4f band to O2p band and the defect level to O2p band. And these defects levels were located in the range of 1 eV around Ce4f band.

  3. Room-temperature synthesis and characterization of porous CeO2 thin films

    International Nuclear Information System (INIS)

    CeO2 thin films with hexagonal-shaped pores were successfully prepared by a facile electrodeposition at room temperature combined with an etching process. By using electrodeposited ZnO nanorods as a soft template, the morphology, and microstructure of the CeO2 could be controlled. TEM observation indicated that as-prepared CeO2 film is composed of nanocrystals with average size of several nanometers, while XPS analysis showed the coexistence of Ce3+ and Ce4+ in the film. The photoluminescence properties of CeO2 films were measured, which showed much higher sensitivity compared to bare substrate. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Characterization of thin CeO2 films electrochemically deposited on HOPG

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Preparation of proton exchange membrane fuel cells catalyst using electrochemical thin film deposition. • Electrodeposition thin films of CeO2 on HOPG substrates. • The samples were characterized by in-situ AFM and ex-situ XPS. • XPS results reveal that the electrochemically deposited cerium oxide films are stoichiometric. • Exposing the films to ambient air, cracking structures are formed. - Abstract: Electrodeposition is widely used for industrial applications to deposit thin films, coatings, and adhesion layers. Herein, CeO2 thin films were deposited on a highly oriented pyrolytic graphite (HOPG) substrate by cathodic electrodeposition. The influence of the deposition parameters on the yield and on the film morphology is studied and discussed. Morphology and composition of the electrodeposited films were characterized by in-situ atomic force microscopy (AFM), scanning electron microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). By AFM we show that the thickness of CeO2 films can be controlled via the Ce3+ concentration in solution and the deposition time. After exposing the films to ambient air, cracking structures are formed, which were analyzed by AFM in detail. The chemical composition of the deposits was analyzed by XPS indicating the formation of nearly stoichiometric CeO2

  5. Effect of samarium doping on electrodeposited CeO2 thin film

    International Nuclear Information System (INIS)

    Samarium-doped cerium oxide (CeO2:Sm) and undoped cerium oxide (CeO2) thin films were fabricated by electrodeposition on biaxially textured Ni-3% W substrates. The electrodeposited layers were annealed for several hours at temperatures ranging from 910 to 980 C. The resulting crystalline films were investigated by XRD and SEM. The CeO2 crystallite size was correlated to the formation of microcrack in CeO2 and CeO2:Sm using the Scherrer equation of XRD analysis. Crack-free films with an average grain size of about 28 nm were obtained for both Ce0.92Sm0.08O2-δ and Ce0.8Sm0.2O2-δ films. Sm doping strongly affects the crystallite size, crystal structure, texture, and crack formation in ceria films. The lattice parameter a increases and crystallite size is reduced with increased Sm doping. All electrodeposited films are highly biaxially textured. When compared to Ni-based substrates, improvements in the out-of-plane and in-plane texture in ceria- and Sm-doped ceria films were achieved. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Texture development of CeO2 thin films deposited by ion beam assisted deposition

    International Nuclear Information System (INIS)

    CeO2 thin films were prepared on amorphous quartz glass substrates by the ion beam assisted deposition (IBAD) technique at room temperature. In order to control both the in-plane and out-of-plane texture of the films, a special geometrical arrangement of the ion sources, the target, and the substrate was used. A new concept, considering the role of reflected particles from the target, which we call self-IBAD, was introduced. The structural properties of the CeO2 films were investigated by x-ray diffraction. Good biaxially textured films were obtained with out-of-plane mosaic spreads of 3.0 deg. and in-plane alignment of 10.8 deg. C

  7. Resistive switching behaviour of highly epitaxial CeO2 thin film for memory application

    International Nuclear Information System (INIS)

    We report on the remarkable potential of highly epitaxial and pure (001)-oriented CeO2 thin films grown on conducting Nb-doped SrTiO3 (NSTO) substrates by laser molecular beam epitaxy for nonvolatile memory application. Resistive switching (RS) devices with the structure of Au/epi-CeO2/NSTO exhibit reversible and steady bipolar RS behaviour with large high/low resistance ratio and a narrow dispersion of the resistance values. Detailed analysis of the conduction mechanisms reveals that the trapping/detrapping processes and oxygen vacancies migration play important roles in the switching behaviour. In the light of XPS measurement results, the CeO2/NSTO interface with oxygen vacancies or defects is responsible for the RS effect. Furthermore, a model is proposed to explain this resistance switching behaviour. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Surface potentials of (111), (110) and (100) oriented CeO2-x thin films

    Science.gov (United States)

    Wardenga, Hans F.; Klein, Andreas

    2016-07-01

    Differently oriented CeO2 thin films were prepared by radio frequency magnetron sputter deposition from a nominally undoped CeO2 target. (111), (110) and (100) oriented films were achieved by deposition onto Al2O3(0001)/Pt(111), MgO(110)/Pt(110) and SrTiO3:Nb(100) substrates, respectively. Epitaxial growth is verified using X-ray diffraction analysis. The films were analyzed by in situ photoelectron spectroscopy to determine the ionization potential, work function, Fermi level position and Ce3+ concentration at the surface in dependence of crystal orientation, deposition conditions and post-deposition treatment in reducing and oxidizing atmosphere. We observed a very high variation of the work function and ionization potential of more than 2 eV for all surface orientations, while the Fermi level varies by only 0.3 eV within the energy gap. The work function generally decreases with increasing Ce3+ surface concentration but comparatively high Ce3+ concentrations remain even after strongly oxidizing treatments. This is related to the presence of subsurface oxygen vacancies.

  9. Integration of atomic layer deposition CeO2 thin films with functional complex oxides and 3D patterns

    International Nuclear Information System (INIS)

    We present a low-temperature, < 300 °C, ex-situ integration of atomic layer deposition (ALD) ultrathin CeO2 layers (3 to 5 unit cells) with chemical solution deposited La0.7Sr0.3MnO3 (LSMO) functional complex oxides for multilayer growth without jeopardizing the morphology, microstructure and physical properties of the functional oxide layer. We have also extended this procedure to pulsed laser deposited YBa2Cu3O7 (YBCO) thin films. Scanning force microscopy, X-ray diffraction, aberration corrected scanning transmission electron microscopy and macroscopic magnetic measurements were used to evaluate the quality of the perovskite films before and after the ALD process. By means of microcontact printing and ALD we have prepared CeO2 patterns using an ozone-robust photoresist that will avoid the use of hazardous lithography processes directly on the device components. These bilayers, CeO2/LSMO and CeO2/YBCO, are foreseen to have special interest for resistive switching phenomena in resistive random-access memory. - Highlights: • Integration of atomic layer deposition (ALD) CeO2 layers on functional complex oxides • Resistive switching is identified in CeO2/La0.7Sr0.3MnO3 and CeO2/YBa2Cu3O7 bilayers. • Study of the robustness of organic polymers for area-selective ALD • Combination of ALD and micro-contact printing to obtain 3D patterns of CeO2

  10. Structural, morphological and electrical properties of spray deposited nano-crystalline CeO2 thin films

    International Nuclear Information System (INIS)

    Research highlights: → Nanocrystalline, uniform, dense, and adherent cerium oxide (CeO2) thin films have been successfully deposited by a simple and cost effective spray pyrolysis technique. CeO2 films were deposited at low substrate and annealing temperatures of 350 deg. C and 500 deg. C, respectively. The deposited film showed high oxygen ion conductivity of 5.94 x 10-3 S cm-1 at 350 deg. C. This is due to the fact that in nano-crystalline materials grain boundaries have high defect densities and the atoms there have high mobility. Due to its nano-crystalline nature, the deposited ceria material will have high sinterability, high surface area and hence can have various applications such as in intermediate temperature solid oxide fuel cell, gas sensors, electrochromic smart window devices, in corrosion protection and catalysis. - Abstract: Nanocrystalline, uniform, dense, and adherent cerium oxide (CeO2) thin films have been successfully deposited by a simple and cost effective spray pyrolysis technique. CeO2 films were deposited at low substrate and annealing temperatures of 350 deg. C and 500 deg. C, respectively. Films were characterized by differential thermal analysis, X-ray diffraction, scanning electron microscopy, atomic force microscopy; two probe resistivity method and impedance spectroscopy. X-ray diffraction analysis revealed the formation of single phase, well crystalline thin films with cubic fluorite structure. Crystallite size was found to be in the range of 10-15 nm. AFM showed formation of smooth films with morphological grain size 27 nm. Films were found to be highly resistive with room temperature resistivity of the order of 107 Ω cm. Activation energy was calculated and found to be 0.78 eV. The deposited film showed high oxygen ion conductivity of 5.94 x 10-3 S cm-1 at 350 deg. C. Thus, the deposited material shows a potential application in intermediate temperature solid oxide fuel cells (IT-SOFC) and might be useful for μ-SOFC and

  11. The influence of Er3+ doping on the structural and optical properties of CeO2 thin films grown by PED

    International Nuclear Information System (INIS)

    Erbium doped CeO2 thin films were deposited on both Corning glass substrates and indium doped tin oxide (ITO) coated glass substrates by pulsed e-beam deposition (PED) method at room temperature. Structural features of Er doped CeO2 thin films were studied with X-ray diffraction (XRD) and micro-Raman spectra. The XRD patterns of all films showed polycrystalline nature and cubic crystalline structure. Raman active peaks for both undoped CeO2 and Er doped CeO2 films were determined at ∼465 cm−1. The Raman shift observed in this study can also be assigned to Raman active modes of CeO2 that are shifted from the original position due to different doping concentration. The optical properties of CeO2 films and Er doped CeO2 films, which were determined from transmittance and reflectance measurements at room temperature, were very similar in character. The refractive indices and extinction coefficients, which were calculated from 3.5 to 1.25 eV (300–1000 nm), were between 1.5–3 and 0.05–0.2, respectively. The optical band gaps were deduced from the absorption coefficient according to solid band theory. The electrochromic measurements revealed that 2% Er doped CeO2 films grown on ITO + WO3 substrates had highest charge density compared to the other samples. Long-time cyclic voltammetry (CV) and chronoamperometry (CA) measurements were carried out to investigate the stability of this film.

  12. Etch characteristics of CeO2 thin film in Ar/CF4/Cl2 plasma

    International Nuclear Information System (INIS)

    The effect of Cl2 addition into CF4/Ar plasma on etching of CeO2 thin film was studied in terms of etch rate and selectivity. We obtained the maximum etch rate of 250 Aa/min at 10% Cl2 addition into CF4/Ar gas mixing ratio of 20%. The maximum etch rate may be explained by the variation of volume density for Cl atoms and by the concurrence of two etching mechanisms such as physical sputtering and chemical reaction with formation of low-volatile products, which can be desorbed only by ion bombardment. In addition, the roles of ion bombardment include destruction of Ce-O bonds to facilitate the chemical interaction of Ce with chlorine and fluorine atoms. The variation of volume density for Cl, F, and Ar atoms are measured by optical emission spectroscopy. The chemical states of CeO2 thin films before and after etching are investigated with x-ray photoelectron spectroscopy

  13. Epitaxial growth of CeO2 thin film on cube textured NiW substrate using a propionate-based metalorganic deposition (MOD) method

    International Nuclear Information System (INIS)

    Highlights: ► Accurate study of decomposition of cerium propionate based precursors. ► Epitaxial CeO2 thin film on Ni–W substrate in a reducing atmosphere. ► The films exhibit a high degree of epitaxy within the Dimos criteria. ► The obtained CeO2 films are appropriate for YBCO based coated conductor application. - Abstract: The CeO2 films were epitaxially grown on (0 0 1)[1 0 0]Ni–W biaxially textured substrate using a propionate-based metalorganic deposition (MOD) method. The as deposited CeO2 films exhibit a sharp biaxial texture, with a full width at half maximum (FWHM) of φ and ω-scans of about 7.15° and 7.8°, respectively. The in-plane and out-of plane epitaxial relationship are [0 0 1]CeO2//[0 0 1]Ni–W and [1 0 0]CeO2//[1 1 0]Ni–W, respectively. The morphology of the films is strongly correlated with the film thickness and crystallization temperature. Thus, the 0.3 μm thick film crystallized at 1100 °C has a smooth surface free of cracks or voids with a root mean square roughness (RMS) of about 2.5 nm, whilst the 1.1 μm thick film presents many cracks and a low density of voids. The cracks along the substrate grain boundaries observed in the thicker films take place in the already crystallized film during the rapid cooling process due to difference between the thermal expansion coefficients of the film and metallic Ni–W substrate.

  14. Growth mode, morphology, and reducibility of CeO2(111) thin films on Cu(111)

    International Nuclear Information System (INIS)

    We investigate morphology and degree of reduction in model oxide system CeO2 (ceria) on Cu(111) using scanning tunneling microscopy and photoelectron spectroscopy. We identify growth mechanisms of ceria on Cu(111) - formation of incomplete oxide interfacial layer and formation of three-dimensional ceria pyramids by stacking of monolayer-high islands. Using these mechanisms we control the coverage, the number of open monolayers, and the step density of ceria thin films on Cu(111). Annealing in vacuum allows us to control besides the morphology also the degree of ceria surface reduction. We find a correlation between surface reduction and morphological stability in annealed ceria layers. Oriented and stoichiometric thin films of ceria on Cu(111) can be prepared at temperatures as low as 150 C and 250 C. Both the morphology and the degree of reduction of these films readily change with increasing temperature, which must be accounted for in evaluating temperature-programmed experiments with ceria on Cu(111).

  15. A photoemission study of the interaction of Ga with CeO2(1 1 1) thin films

    International Nuclear Information System (INIS)

    The interaction of gallium with CeO2(1 1 1) layers was studied using standard and resonant photoelectron spectroscopy, by means of both a laboratory X-ray source and tunable synchrotron light. Firstly a 1.5-nm thick CeO2 film was grown on a Cu(1 1 1) substrate. Secondly Ga was deposited in six steps up to a thickness of 0.35 nm, at room temperature. The interaction of gallium with the oxide layer induced partial CeO2 reduction, and gallium oxidation. The photoemission data suggest that a mixed Ga-Ce-O oxide was established similarly to the Sn-Ce-O case for Sn deposited on cerium oxide layers. As a consequence, gallium-induced weakening of Ce-O bonds provides a higher number of active sites on the surface that play a major role in its catalytic behaviour

  16. Fabrication of catalytically active nanocrystalline samarium (Sm)-doped cerium oxide (CeO2) thin films using electron beam evaporation

    International Nuclear Information System (INIS)

    Samarium (Sm)-doped cerium oxide (CeO2) thin films were fabricated using electron beam evaporation technique. The synthesized films were deposited either on glass or ITO substrates and studied their nature by annealing at different temperatures. The optical properties and other morphological studies were done by UV–Vis, XRD, XPS, SEM, EDS, and FT-IR analysis. XRD and XPS analysis clearly confirm the presence of Sm in the ceria site. From the SEM study, it was found that after annealing at high temperature (∼300 or 500 °C), the particles size was reduced due to breakdown of large aggregates of particles which is also confirmed from UV–Vis, XPS, and XRD analyses. The FT-IR study proves the presence of –COO–, –OH, or ammonium group on the particles surface. The deposition of Sm-doped CeO2 nanomaterials was found more feasible on ITO substrate compared to that of glass substrate in terms of stability and depth of film thickness. The Sm-doped CeO2 nanomaterial acts as a re-usable catalyst for the reduction of organic dye molecules in the presence of NaBH4. The catalysis rate was compared by considering the electron transfer process during the reduction. The synthesized Sm-doped CeO2 thin films might find wide variety of applications in various emerging fields like solid oxide fuel cells (SOFCs), oxygen sensor or as catalyst in different types of organic and inorganic catalytic reactions. The fabrication process is very simple, straightforward, less time consuming, and cost effective.Graphical Abstract

  17. Surface morphology, optical and electrochemical properties of undoped and Ni-doped CeO2 thin films prepared by polymeric precursor method

    Science.gov (United States)

    Khosousi Sani, Zara; Esmaeli Ghodsi, Farhad; Mazloom, Jamal

    2016-04-01

    In this study, undoped and Ni-doped CeO2 thin films were deposited onto glass and ITO substrates by polymeric precursor (Pechini) method. Grazing incidence X-ray diffraction analysis revealed that the ceria thin film has a cerianite structure with the average crystallite size of 14 nm while the doped samples are amorphous. X-ray photoelectron spectroscopy (XPS) confirmed the presence of predominant Ce4+ oxidation state of ceria and Ni2+ in the films. Scanning electron microscopy (SEM) micrographs showed that the surface texture is crack free and the CeO2 grains regularly distributed on the surface. Optical constant (refractive index and extinction coefficient) and thickness of films were calculated using pointwise unconstraint minimization approach. The optical transmittance increases and the absorption edge has a blue shift by Ni incorporation. The highest band gap value (i.e., 3.43 eV) was obtained for 2.5 mol.% Ni doping sample. The refractive index and extinction coefficient of ceria films were decreased by Ni doping. The evaluated thicknesses are in the range of 150-170 nm. The strength of interband transition was appraised as a function of nickel content by using dielectric function. Luminescent emission intensity of the ceria film was enhanced by Ni doping. Cyclic voltammetry (CV) measurement revealed that the total charge density and ion storage capacitance of ceria thin film were increased by Ni doping.

  18. Ultrafast pump-probe spectroscopy studies of CeO2 thin film deposited on Ni-W substrate by RF magnetron sputtering

    Science.gov (United States)

    Singh, Preetam; Srivatsa, K. M. K.; Jewariya, Mukesh

    2016-08-01

    This study presents the first investigation of rapid dynamical processes that occur in pure CeO2 thin film, using ultra fast pump-probe spectroscopy at room temperature. For this purpose we have used a single (200) oriented CeO2 film deposited on biaxially textured Ni-W substrate by RF magnetron sputtering technique. The ultrafast transient spectra show initial sharp rise transition followed by an exponential photon decay. This rise time is about 10 ps irrespective of the probe wavelengths range 500-800 nm. The initial decay constant (τ) at 500 nm probe wavelength is found to be 171 ps, while at 800 nm probe wavelength it is 107.5 ps. The ultrafast absorption spectra show two absorption peaks at 745 and 800 nm, and are attributed to the electronic transitions from 2F7/2-2F5/2 and 1S0-1F3 respectively. The relatively high intensity absorption peak at 745 nm indicates dominant f-f electronic transition. Further, the absorption peak at 745 nm splits into two distinct peaks with respect to delay time, and is attributed to the charge transfer in between Ce4+ and Ce3+ ions. These results indicate that CeO2 itself is a potential candidate and can be used for optical applications.

  19. CeO2 thin film as a low-temperature formaldehyde sensor in mixed vapour environment

    Indian Academy of Sciences (India)

    R Pandeeswari; B G Jeyaprakash

    2014-10-01

    Nanostructured cerium oxide thin film was deposited onto the glass substrate under optimized condition using spray-pyrolysis technique. X-ray diffraction result indicates polycrystalline nature of the film with fluorite-type face-centered-cubic structure. The atomic force micrograph indicates the presence of nanocrystallites over the film surface. The vapour sensing characteristics of the annealed film were studied by chemiresistive method for various concentrations of formaldehyde vapour at room temperature (∼ 30 °C). For 0.5 ppm of formaldehyde vapour, the film shows a response and recovery time of 36 and 1 s, respectively. The vapour sensing properties of the cerium oxide film in mixed environment were studied and reported.

  20. Room-Temperature Ferromagnetism of Co-Doped CeO2 Thin Films on Si(111) substrates

    Institute of Scientific and Technical Information of China (English)

    SONG Yuan-Qiang; ZHANG Huai-Wu; WEN Qi-Ye; LI Yuan-Xun; John Q. Xiao

    2007-01-01

    @@ Using Co2O3 as the Co source, doped cerium oxide thin films with the composition of Ce0.97Co0.03O2-δ (CCO)are deposited on Si(111) and glass substrates by pulse laser deposition technique. X-ray diffraction reveals that CCO films with (111) preferential orientation are grown on Si, while the film on glass is polycrystalline with nanocrystal. X-ray photoelectron spectroscopy shows that the Co displaces the Ce atom and exists in high spin state rather than low spin state, which contributes to the room-temperature ferromagnetism confirmed by vibration sample magnetometer.

  1. Influence of ethanol content in the precursor solution on anodic electrodeposited CeO2 thin films

    International Nuclear Information System (INIS)

    Ceria thin films have been anodically deposited onto 316L stainless steel in bath solutions containing different volume ratios of ethanol (0, 10, 40, 70 and 100% v/v). The influence of ethanol content on the electroplating behavior, and the structural and corrosion properties of the cerium oxide films were studied with electrochemical impedance spectroscopy, scanning electron microscopy, ellipsometry, X-ray diffraction, and Raman and X-ray photoelectron spectroscopy. Results show that ethanol content plays a significant role on the properties of the deposited ceria films but negligible effect on their electroplating behavior. The as-deposited films are mostly in the Ce(IV) oxidation state and the stoichiometry is around CeO1.90 for all samples. With the increase of ethanol content from 0 to 100% v/v, the average grain diameter and film thickness of the obtained ceria film decrease from 16.8 nm to 11.1 nm and from 32.9 nm to 15.8 nm, respectively. Using a deposition bath solution containing 10% v/v ethanol, a layer of compacted yellowish gold ceria film with the minimum porosity of 19.9%, mean crystalline diameter of 15.4 nm, and maximum corrosion resistance of 3.31 × 10−5 Ω has been obtained. - Highlights: • Ethanol plays a negligible effect on ceria film anodic electroplating behavior. • Average grain diameter and thickness of the film decrease with the ethanol addition. • Appropriate amount of ethanol can markedly improve the film quality. • Film color changes gradually with increasing ethanol addition into deposition bath. • Nanocrystalline CeO1.90 films of golden yellowish have been obtained

  2. Angular properties of pure and Ca-substituted YBa2Cu3O7-δ superconducting thin films grown on SrTiO3 and CeO2 buffered Al2O3 substrates

    International Nuclear Information System (INIS)

    In this work transport properties of superconducting 10 at.% Ca-substituted YBCO thin films grown on (1 0 0)-SrTiO3 single crystal substrate (STO) and superconducting pure and 10 at.% Ca-substituted YBCO thin films grown on CeO2 buffered Al2O3 substrates (CAO) have been analyzed as a function of the temperature, applied magnetic field and angle between magnetic field direction and the direction normal to the film surfaces. Particularly, the angular analysis provides an easy way to discriminate between isotropic point defects and correlated pinning sites. Despite the intragrain pinning mechanisms remained unaffected by Ca substitution, a detrimental effect on grain boundary properties clearly emerged for 10 at.% Ca concentration. This effect is enhanced in sample grown on CeO2 buffered sapphire where a more disturbed grain boundary is expected resulting in an enhancement of the correlated pinning, already observed in pure YBCO films grown on CAO, and in a reduction of the intrinsic pinning efficiency

  3. Electrochemical and optical properties of CeO2-SnO2 and CeO2-SnO2:X (X = Li, C, Si films

    Directory of Open Access Journals (Sweden)

    Berton Marcos A.C.

    2001-01-01

    Full Text Available Thin solid films of CeO2-SnO2 (17 mol% Sn and CeO2-SnO2:X (X = Li, C and Si were prepared by the sol-gel route, using an aqueous-based process. The addition of Li, C and Si to the precursor solution leads to films with different electrochemical performances. The films were deposited by the dip-coating technique on ITO coated glass (Donnelly Glass at a speed of 10 cm/min and submitted to a final thermal treatment at 450 °C during 10 min in air. The electrochemical and optical properties of the films were determined from the cyclic voltammetry and chronoamperometry measurements using 0.1 M LiOH as supporting electrolyte. The ion storage capacity of the films was investigated using in situ spectroelectrochemical method and during the insertion/extraction process the films remained transparent. The powders were characterized by thermal analysis (DSC/TGA and X-ray diffraction.

  4. Growth and Photoluminescence of Epitaxial CeO2 Film on Si (111) Substrate

    Institute of Scientific and Technical Information of China (English)

    GAO Fei; ZHANG Jian-Hui; QIN Fu-Guang; YAO Zhen-Yu; LIU Zhi-Kai; WANG Zhan-Guo; LIN Lan-Ying

    2001-01-01

    A CeO2 film with a thickness of about 80nm was deposited by a mass-analysed low-energy dual ion beam deposition technique on an Si(111) substrate. Reflection high-energy electron diffraction and x-ray diffraction measurements showed that the film is a single crystal. The tetravalent state of Ce in the film was confirmed by xray photoelectron spectroscopy measurements, indicating that stoichiometric CeO2 was formed. Violet/blue light emission (379.5 nm) was observed at room temperature, which may be tentatively explained by charge transitions from the 4f band to the valence band of CeO2.

  5. Tunable flux pinning landscapes achieved by functional ferromagnetic Fe2O3:CeO2 vertically aligned nanocomposites in YBa2Cu3O7−δ thin films

    International Nuclear Information System (INIS)

    Highlights: • Functional ferromagnetic (Fe2O3)x:(CeO2)1−x vertically aligned nanocomposites (VAN). • An ordered arrangement of ferromagnetic Fe2O3 nanoinclusions. • Significant in-field improvement of Jc (H//c) in both VAN nanolayer capped and buffered samples. • Tc above 90 K and the Jcsf maximized at 3.07 MA/cm2 (75 K) and 9.2 MA/cm2 (65 K) for 30% Fe2O3 sample. - Abstract: Functional ferromagnetic (Fe2O3)x:(CeO2)1−x vertically aligned nanocomposite (VAN) layers were deposited as either buffer or cap layers for YBa2Cu3O7−δ (YBCO) thin films. The composition of Fe2O3 dopants in the VAN nanolayers is controlled at 10%, 30% and 50% in order to create different arrangements of Fe2O3 and CeO2 nanopillars and therefore to tune the flux pining landscapes. The composition variation provides tunable and ordered arrangements of magnetic nanodopants and interfacial defects as pinning centers in the YBCO thin films. The superconducting property measurements show that most doped samples obtain a Tc above 90 K and the Jcsf measured at 75 K and 65 K maximized at 3.07 MA/cm2 and 9.2 MA/cm2 for 30% Fe2O3 VAN doped sample. As the temperature decreased to 5 K, the sample with 50% Fe2O3 VAN doped sample show the best pinning effect due to pronounced magnetic pinning effects. This work demonstrates the tunable density of magnetic pinning centers can be achieved by VAN to meet the specific pinning requirement

  6. Effect of annealing temperature on oxygen vacancy concentrations of nanocrystalline CeO2 film

    International Nuclear Information System (INIS)

    Highlights: • Nanocrystalline CeO2 films were prepared by a facile sol–gel spin coating method. • Oxygen vacancy concentrations can be controlled by annealing temperatures. • The films show perfect thermal stability at various annealing temperatures. • PL, XPS and Raman spectra are obviously affected by oxygen vacancy concentrations. - Abstract: Nanocrystalline CeO2 films with around 250 nm thickness were deposited on Si (0 0 1) substrates by a facile sol–gel process with spin coating method. The films are of cubic fluorite structure, and some lattice distortions exist in the film. The phase stability and small change in lattice parameter at different annealing temperatures indicate the good thermal stability of the nanocrystalline CeO2 films. The average grain-size and surface roughness of the films increase with the increase of annealing temperature. The content of Ce3+ and oxygen vacancy is very high in the nanocrystalline CeO2 films, while, the films still remain cubic phase regardless of its high level non-stoichiometric composition. All the annealed samples show two emission bands, and the defect peak centered at ∼500 nm shows a red-shift. The intensity of the green-emission band increases with the increasing annealing temperature, which might result from the increasing concentration of oxygen vacancies caused by the valence transition from Ce4+ to Ce3+, and it has also been confirmed by the X-ray photoelectron spectroscopy results. This work demonstrates that oxygen vacancy plays an important role on the properties of the nanocrystalline CeO2 film, and it also provides a possible way to control the concentration of oxygen vacancies

  7. Microstructure, magnetic, and low-field magnetotransport properties of self-assembled (La0.7Sr0.3MnO3)0.5:(CeO2)0.5 vertically aligned nanocomposite thin films

    International Nuclear Information System (INIS)

    Two-phase (La0.7Sr0.3MnO3)0.5:(CeO2)0.5 (LSMO:CeO2) heteroepitaxial nanocomposite films were grown on SrTiO3 (STO) (001) by pulsed laser deposition (PLD). X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that LSMO:CeO2 films epitaxially grow on STO as self-assembled vertically aligned nanocomposite (VAN). Magnetic and magnetotransport measurements demonstrate that the LSMO phase in the VAN structure behaves differently from its epitaxial single-phase counterpart, e.g. greatly enhanced coercivity (HC) and low-field magnetoresistance (LFMR). The enhanced properties in the VAN system are attributed to the interaction between the perovskite and the secondary phase or phase boundary. The results suggest that the growth of functional oxide in another oxide matrix with vertical heteroepitaxial form is a promising approach to achieve new functionality that may not be easily realized in the single epitaxial phase.

  8. Photon management properties of rare-earth (Nd,Yb,Sm)-doped CeO2 films prepared by pulsed laser deposition.

    Science.gov (United States)

    Balestrieri, Matteo; Colis, Silviu; Gallart, Mathieu; Schmerber, Guy; Bazylewski, Paul; Chang, Gap Soo; Ziegler, Marc; Gilliot, Pierre; Slaoui, Abdelilah; Dinia, Aziz

    2016-01-28

    CeO2 is a promising material for applications in optoelectronics and photovoltaics due to its large band gap and values of the refractive index and lattice parameters, which are suitable for silicon-based devices. In this study, we show that trivalent Sm, Nd and Yb ions can be successfully inserted and optically activated in CeO2 films grown at a relatively low deposition temperature (400 °C), which is compatible with inorganic photovoltaics. CeO2 thin films can therefore be efficiently functionalized with photon-management properties by doping with trivalent rare earth (RE) ions. Structural and optical analyses provide details of the electronic level structure of the films and of their energy transfer mechanisms. In particular, we give evidence of the existence of an absorption band centered at 350 nm from which energy transfer to rare earth ions occurs. The transfer mechanisms can be completely explained only by considering the spontaneous migration of Ce(3+) ions in CeO2 at a short distance from the RE(3+) ions. The strong absorption cross section of the f-d transitions in Ce(3+) ions efficiently intercepts the UV photons of the solar spectrum and therefore strongly increases the potential of these layers as downshifters and downconverters. PMID:26699802

  9. Structural and electrical properties of SrTiO3 films grown on CeO2 buffered sapphire

    International Nuclear Information System (INIS)

    The physical properties of complex oxides like ferroelectric Perovskite are strongly connected with their composition, structure and structural imperfections. Lattice constants and thermal properties of substrate materials and deposited films are usually different. In the case of thin epitaxial films this difference can be used for engineering of properties of ferroelectric materials via mechanical strain due to changing of film thickness and preparation conditions. In the present work we report on results of measuring the strain of both in buffer CeO2 and STO films on r-cut sapphire. Ferroelectric films were deposited by PLD. Different types of strain lead to various structural modifications in films. The resulting type of distortion and defects are investigated by high-resolution X-ray analysis. Electrical properties of STO films of various thicknesses are measured using planar capacitors in a wide frequencies range. It is shown that in the thinner films the stress is compensated by misfit dislocations generated during growth and a deformation of the STO lattice. With increasing film thickness cracks develop in two crystalline directions, i.e. along the [1210] and, additionally, the [1010] directions of r-cut sapphire. The strained films show a strong modification of temperature dependence of the dielectric permittivity.

  10. Near-infrared luminescence of Tm3+-doped CeO2 films based on silicon substrates

    International Nuclear Information System (INIS)

    CeO2/Tm2O3 multilayer films were deposited on silicon substrates by electron-beam evaporation. Tm3+ ions were doped in CeO2 after the films were annealed in oxygen atmosphere at 1000 C. The doping concentration of Tm3+ varies in the range of 0.1-3 mol%. A series of near-infrared emission peaks were observed under the excitation of 330 nm, which correspond to 1G4-3H5, 3H4-3H6, 1G4-3H4, 3H5-3H6, 3F2-3H5, 3H4-3F4, 1G4-3F3,2 and 3F4-3H6 transitions of Tm3+, respectively. The dominant transition of 3H4-3H6 near 805 nm was within optical transmission window. The luminescence properties and the crystal structure of CeO2:Tm3+ films were investigated by excitation and emission spectroscopy and X-ray diffraction. Meanwhile, the substitution process of Ce4+ by Tm3+ was illustrated, and lattice expansion of the matrix CeO2 gave rise to the increase in FWHM of CeO2 diffraction peaks. In addition, the effect of Tm3+ concentration on photoluminescence was also studied, and the optimal concentration of Tm3+ was 0.5 mol%. (orig.)

  11. Unexpected Li2O2 Film Growth on Carbon Nanotube Electrodes with CeO2 Nanoparticles in Li-O2 Batteries.

    Science.gov (United States)

    Yang, Chunzhen; Wong, Raymond A; Hong, Misun; Yamanaka, Keisuke; Ohta, Toshiaki; Byon, Hye Ryung

    2016-05-11

    In lithium-oxygen (Li-O2) batteries, it is believed that lithium peroxide (Li2O2) electrochemically forms thin films with thicknesses less than 10 nm resulting in capacity restrictions due to limitations in charge transport. Here we show unexpected Li2O2 film growth with thicknesses of ∼60 nm on a three-dimensional carbon nanotube (CNT) electrode incorporated with cerium dioxide (ceria) nanoparticles (CeO2 NPs). The CeO2 NPs favor Li2O2 surface nucleation owing to their strong binding toward reactive oxygen species (e.g., O2 and LiO2). The subsequent film growth results in thicknesses of ∼40 nm (at cutoff potential of 2.2 V vs Li/Li(+)), which further increases up to ∼60 nm with the addition of trace amounts of H2O that enhances the solution free energy. This suggests the involvement of solvated superoxide species (LiO2(sol)) that precipitates on the existing Li2O2 films to form thicker films via disproportionation. By comparing toroidal Li2O2 formed solely from LiO2(sol), the thick Li2O2 films formed from surface-mediated nucleation/thin-film growth following by LiO2(sol) deposition provides the benefits of higher reversibility and rapid surface decomposition during recharge. PMID:27105122

  12. Dip-coated TiO2CeO2 films as transparent counter-electrode for transmissive electrochromic devices

    OpenAIRE

    Baudry, Paul; Rodrigues, A. C. M.; Michel A. Aegerter; Bulhoes, Luis O. S.

    1990-01-01

    The dip-coating process is an attractive way for the preparation of thin films used in the field of electrochromism. The scope of the present paper is focused on the TiO2CeO2 compounds since they exhibit a reversible electrochemical insertion of lithium ions maintaining a high optical transmissivity. These films can be used as transparent counter-electrode in an all solid state electrochromic transmissive device with, for example, WO3 as electrochromic material and a lithium conductive po...

  13. Study of the growth of biaxially textured CeO2 films during ion-beam-assisted deposition

    International Nuclear Information System (INIS)

    Biaxially textured CeO2 films were deposited on Hastelloy C276 substrates at room temperature using ion-beam-assisted e-beam evaporation with the ion beam directed at 55 deg. to the normal of the film plane. The crystalline structure and in-plane orientation of films were investigated by x-ray diffraction 2θ-scan and φ-scan. The orientation of the films was studied as a function of ion-to-atom ratio and film thickness. The ion-to-atom ratio was varied by independently adjusting the deposition rate and the ion current density. Under optimum condition, (200) textured CeO2 films have been successfully grown on Hastelloy C276

  14. Study of the growth of biaxially textured CeO2 films during ion-beam-assisted deposition

    Science.gov (United States)

    Kim, Chang Su; Jo, Sung Jin; Jeong, Soon Moon; Kim, Woo Jin; Baik, Hong Koo; Lee, Se Jong; Song, Kie Moon

    2005-03-01

    Biaxially textured CeO2 films were deposited on Hastelloy C276 substrates at room temperature using ion-beam-assisted e-beam evaporation with the ion beam directed at 55° to the normal of the film plane. The crystalline structure and in-plane orientation of films were investigated by x-ray diffraction 2θ-scan and phgr-scan. The orientation of the films was studied as a function of ion-to-atom ratio and film thickness. The ion-to-atom ratio was varied by independently adjusting the deposition rate and the ion current density. Under optimum condition, (200) textured CeO2 films have been successfully grown on Hastelloy C276.

  15. Memory resistive switching in CeO2-based film microstructures patterned by a focused ion beam

    DEFF Research Database (Denmark)

    Velichko, A.; Boriskov, P.; Grishin, A.;

    2014-01-01

    Heteroepitaxial CeO2 (80 nm)/La0.5Sr0.5CoO3 (500 nm) film structure has been pulsed laser deposited on a sapphire substrate. The Ag/CeO2 microjunctions patterned by a focused ion beam on a La0.5Sr0.5CoO3 film exhibit reproducible reversible switching between a high resistance state (OFF...

  16. Chemical composition and corrosion protection of silane films modified with CeO2 nanoparticles

    International Nuclear Information System (INIS)

    The present work aims at understanding the role of CeO2 nanoparticles (with and without activation in cerium(III) solutions) used as fillers for hybrid silane coatings applied on galvanized steel substrates. The work reports the improved corrosion protection performance of the modified silane films and discusses the chemistry of the cerium-activated nanoparticles, the mechanisms involved in the formation of the surface coatings and its corrosion inhibition ability. The anti-corrosion performance was investigated using electrochemical impedance spectroscopy (EIS), the scanning vibrating electrode technique (SVET) and d.c. potentiodynamic polarization. The chemical composition of silanised nanoparticles and the chemical changes of the silane solutions due to the presence of additives were studied using X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance spectroscopy (NMR), respectively. The NMR and XPS data revealed that the modified silane solutions and respective coatings have enhanced cross-linking and that silane-cerium bonds are likely to occur. Electrochemical impedance spectroscopy showed that the modified coatings have improved barrier properties and the SVET measurements highlight the corrosion inhibition effect of ceria nanoparticles activated with Ce(III) ions. Potentiodynamic polarization curves demonstrate an enhanced passive domain for zinc, in the presence of nanoparticles, in solutions simulating the cathodic environment.

  17. Electrical and structural characterization of PLD grown CeO2–HfO2 laminated high-k gate dielectrics

    NARCIS (Netherlands)

    Karakaya, K.; Barcones, B.; Rittersma, Z.M.; Berkum, van J.G.M.; Verheijen, M.A.; Rijnders, G.; Blank, D.H.A.

    2006-01-01

    The electrical and physical properties of CeO2–HfO2 nanolaminates deposited by pulsed laser deposition (PLD) are investigated. The properties of the nanolaminates are compared with binary CeO2 and HfO2 thin films. Layers were deposited using CeO2 and HfO2 targets at substrate temperatures between 22

  18. Faceting of (001) CeO2 Films: The Road to High Quality TFA-YBa2Cu3O7 Multilayers

    International Nuclear Information System (INIS)

    CeO2 films are technologically important as a buffer layer for the integration of superconducting YBa2Cu3O7 films on biaxially textured Ni substrates. The growth of YBa2Cu3O7 layers on the CeO2 cap layers by the trifluoroacetate (TFA) route remains a critical issue. To improve the accommodation of YBa2Cu3O7 on CeO2, surface conditioning or CeO2 is required. In this work we have applied ex-situ post-processes at different atmospheres to the CeO2 layers deposited on YSZ single crystals using rf sputtering. XPS analysis showed that post-annealing CeO2 layer in Ar/H2/H2O catalyses in an unexpected way the growth of (001)- terraces. We also report on the growth conditions of YBa2Cu3O7-TFA on CeO2 buffered YSZ single crystal grown by chemical solution deposition and we compare them with those leading to optimized YBa2Cu3O7-TFA films on LaAlO3 single crystals. Critical currents up to 1.6 MA/cm2 at 77 K have been demonstrated in 300 nm thick YBa2Cu3O7 layers on CeO2/YSZ system. The optimized processing conditions have then been applied to grow YBa2Cu3O7-TFA films on Ni substrates having vacuum deposited cap layers of CeO2

  19. Influence of laser power on the orientation and microstructure of CeO 2 films deposited on Hastelloy C276 tapes by laser chemical vapor deposition

    Science.gov (United States)

    Zhao, Pei; Ito, Akihiko; Tu, Rong; Goto, Takashi

    2010-08-01

    CeO 2 films were prepared on LaMnO 3/MgO/Gd 2Zr 2O 7 multi-coated Hastelloy C276 tapes by laser chemical vapor deposition at different laser power ( PL) from 46 to 101 W. Epitaxial (1 0 0) CeO 2 films were prepared at PL = 46-93 W (deposition temperature, Tdep = 705-792 K). Epitaxial CeO 2 films had rectangular-shaped grains at PL = 46-77 W ( Tdep = 705-754 K), while square-shaped grains were obtained at PL = 85-93 W ( Tdep = 769-792 K). CeO 2 films showed a columnar microstructure. Epitaxial (1 0 0) CeO 2 films with rectangular grains exhibited full width at half maximum of ω-scan on (2 0 0) reflection and ϕ-scan on (2 2 0) reflection of 3.4-3.2° and 6.0-7.2°, respectively. The deposition rate of the epitaxial (1 0 0) CeO 2 films had a maximum of 4.6 μm h -1 at PL = 77 W ( Tdep = 754 K).

  20. The Effect of CeO2 Antireflection Layer on the Optical Properties of Thermochromic VO2 Film for Smart Window System

    Science.gov (United States)

    Koo, Hyun; Shin, Dongmin; Bae, Sung-Hwan; Ko, Kyeong-Eun; Chang, Se-Hong; Park, Chan

    2013-11-01

    CeO2-VO2 bilayer structure was fabricated to investigate the effect of depositing CeO2 film on the optical properties of VO2 film for smart window application. CeO2 was employed as an antireflection (AR) layer material of VO2 film because of its advantages which include high transparency in the visible-near infrared range and high refractive index. All the films were deposited on soda-lime glass substrate by pulsed laser deposition method. Optical calculations were carried out using transfer-matrix method for the purpose of designing CeO2-VO2 bilayer structure with enhanced integrated luminous transmittance (T lum) and switching efficiency (ΔT sol). The optical constants of VO2 and CeO2 films needed for the optical calculation were measured by spectroscopic ellipsometer. The curve of T lum the shape of which depends on the thickness of CeO2 layer, was calculated in each VO2 sample, which showed two maxima. The samples were divided into two groups; one for the highest enhancement of T lum and the other for balanced enhancement between T lum and ΔT sol. The sample with the structure of ~60 nm CeO2 AR layer on 39-nm thick VO2 film showed large increase of T lum (~27%) with ΔT sol of ~5%, which is the largest increase in T lum reported so far. Two samples in the other group showed the balanced enhancement in T lum (~57, ~50%) and ΔT sol (~9, ~10.5%). The effect of CeO2 AR layer on the optical properties of VO2 film was confirmed with the optical calculation and the experimental results. CeO2-VO2 bilayer structure showed notable improvement of optical properties compared to the single VO2 film, indicating that CeO2 layer can be effectively used as the antireflection layer while working as a protective layer that can prevent the oxidation of VO2 layer as well.

  1. Effect of AC and DC voltage on dielectric properties of CeO2 films

    International Nuclear Information System (INIS)

    The capacitance-voltage characteristics have been studied for both AC and DC fields of Al/cerium oxide/Al thin film capacitor structures. Compared to DC fields, these structures can withstand higher AC fields. Capacitance increases with increase in AC and DC fields. The former behaviour is explained on the basis of presence of oxygen vacancies and the latter one is attributed for the Joule heating phenomena. The presence of oxygen vacancies was confirmed from the thermoluminescence studies on these films. (author)

  2. Preparation and Characterization of CeO2-TiO2/SnO2:Sb Films Deposited on Glass Substrates by R.F.Sputtering

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qingnan; DONG Yuhong; NI Jiamiao; WANG Peng; ZHAO Xiujian

    2008-01-01

    CeO2-TiO2 films and CeO2-TiO2/SnO2:Sb(6 mol%)double films were deposited on glass substrates by radio-frequency magnetron sputtering(R.F.Sputtering),using SnO2:Sb(6 mol%)target,and CeO2-TiO2 targets with different molar ratio of CeO2 to TiO2 (CeO2:TiO2=0:1.0;0.1:0.9;0.2:0.8;0.3:0.7;0.4:0.6;0.5:0.5;0.6:0.4; 0.7:0.3; 0.8:0.2;0.9:0.1;1.0:0).The films are characterized by UV-visible transmission and infrared reflection spectra,scanning electron microscopy(SEM),Raman spectroscopy,X-ray photoelectron spectroscopy(XPS)and X-ray diffraction(XRD),respectively.The obtained results show that the amorphous phases composed of CeO2-TiO2 play an important role in absorbing UV, there are Ce3+,Ce4+ and Ti4+ on the surface of the films;the glass substrates coated with CeO2-TiO2(Ce/Ti=0.5:0.5;0.6:0.4)/SnO2:Sb(6 mol%) double films show high absorbing UV(>99),high visible light transmission(75%)and good infrared reflection films can be used as window glass of buildings,automobile and so on.

  3. Development of La3+ Doped CeO2 Thick Film Humidity Sensors

    OpenAIRE

    Chunjie Wang; Aihua Zhang; Hamid Reza Karimi

    2014-01-01

    The humidity sensitive characteristics of the sensor fabricated from 10 mol% La2O3 doped CeO2 nanopowders with particle size 17.26 nm synthesized via hydrothermal method were investigated at different frequencies. It was found that the sensor shows high humidity sensitivity, rapid response-recovery characteristics, and narrow hysteresis loop at 100 Hz in the relative humidity range from 11% to 95%. The impedance of the sensor decreases by about five orders of magnitude as relative humidity in...

  4. Morphology, structural properties and reducibility of size-selected CeO2- x nanoparticle films.

    Science.gov (United States)

    Spadaro, Maria Chiara; D'Addato, Sergio; Gasperi, Gabriele; Benedetti, Francesco; Luches, Paola; Grillo, Vincenzo; Bertoni, Giovanni; Valeri, Sergio

    2015-01-01

    Non-stoichiometric ceria nanoparticles (NPs) were obtained by a gas aggregation source with a magnetron and were mass-selected with a quadrupole mass filter. By varying magnetron power, Ar gas flow, and the length of the aggregation tube, NPs with an average diameter of 6, 9, and 14 nm were synthesized and deposited onto a substrate, thus obtaining NP films. The morphology of the films was studied with scanning electron microscopy, while high resolution transmission electron microscopy was used to gain a deeper insight into the atomic structure of individual NPs. By using X-ray photoelectron spectroscopy we analyzed the degree of reduction of the NPs of different diameters, before and after thermal treatments in vacuum (reduction cycle) and in O2 atmosphere (oxidation cycle) at different temperatures. From this analysis we inferred that the size is an important parameter only at intermediate temperatures. As a comparison, we evaluated the reducibility of an ultra-thin ceria film with the same surface to volume ratio as the 9 nm diameter NPs film, observing that NPs are more reducible than the ceria film. PMID:25671152

  5. Growth and structure of epitaxial CeO2 films on yttria-stabilized ZrO2

    International Nuclear Information System (INIS)

    Thirty to a hundred-nm thick epitaxial CeO2 layers are grown on YSZ (100), (110) and (111) surfaces of yttria-stabilized ZrO2 (YSZ) by electron beam evaporation of Ce in oxygen at reduced pressure. Their growth, structure and thermal stability are studied with several bulk and surface sensitive techniques including Rutherford backscattering spectrometry, cross-sectional high resolution electron microscopy, low energy electron diffraction and low energy reflection electron microscopy. Excellent epitaxy is obtained on all YSZ surfaces at a growth temperature of 750 K. The surfaces of films grown on (111)-oriented substrates are flat, whereas those on the other substrates are faceted into small (111) planes. The grain sizes in the films are in the 10 nm range and smaller

  6. The CeO2-TiO2-ZrO2 sol-gel film: a counter-electrode for electrochromic devices

    International Nuclear Information System (INIS)

    Thin films of CeO2-TiO2-ZrO2 with 23 mol% of Ce, 45 mol% of Ti and 32 mol% of Zr were obtained by the sol-gel method. The precursor sol was prepared from a mixture of Ce(NH4)2 (NO3)6, Ti(OPri)4 and Zr(OPri)4 solubilized in isopropanol and then sonicated. Xerogels were characterized by Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) and X-ray diffraction. The films were deposited by dip-coating technique on a glass plate coated with an indium tin oxide film (ITO) and thermally treated at 80 deg. C for 15 min. and heated at 450 deg. C for 15 min in an oxygen atmosphere. By means of the addition of a lithium salt (LiCF3SO3) to the precursor solution, films with different electrochemical performances were obtained. Their possible use as ion storage (counter-electrode) in electrochromic devices (ECD) was analyzed by spectroelectrochemical measurements using cyclic voltammetry and chronoamperometry coupled to spectrometric measurements

  7. Near-infrared emissions from Yb3+-doped CeO2 and Ce2Si2O7 films based on silicon substrates subjected to thermal treatment

    Science.gov (United States)

    Mu, Guangyao; Wang, Shenwei; Li, Ling; Yin, Xue; Huang, Miaoling; Yi, Lixin

    2016-05-01

    Photoluminescence properties of Yb3+-doped CeO2 films annealed in different atmospheres were investigated. CeO2:Yb3+ films were deposited by electron-beam evaporation technique. Near-infrared emission around 970 nm was observed after annealing the films both in air and in Ar-H2 atmosphere, which is attributed to the Yb3+:2F5/2 → 2F7/2 transition. Optimization of the Yb3+ concentration for the 970 nm luminescence yield was also investigated. Characterized by different methods, Ce2Si2O7 was formed in the films annealed in reducing atmosphere, which was expected to be more applicable for the silicon-based optoelectronic applications.

  8. Biaxially aligned YSZ and CeO2 buffer layers on hastelloy prepared by magnetron IBAD

    International Nuclear Information System (INIS)

    Full text: The development of high-current, flexible superconducting YBCO tapes is based on a metal substrates overcoated with a biaxially aligned oxide buffer layer to serve as a template for the epitaxial growth of c-axis oriented Yba2Cu3O7 thin films. A secondary function of the buffer is to act as a diffusion barrier to metal species to prevent them from poisoning the superconducting film. Widely studied oxide buffer layers include yttria-stabilised zirconia (YSZ) and cerium oxide (CeO2) produced by ion-beam-assisted deposition (IBAD). We have combined IBAD with magnetron sputtering to deposit biaxially aligned YSZ and CeO2 on Hastelloy C276 substrates held at room temperature. The ion beam is directed at 55deg to the normal of the film plane. In addition, we achieved room temperature epitaxial growth of CeO2 films on IBAD YSZ films by bias sputtering to form biaxially aligned CeO2/YSZ bilayers. The crystalline quality and inplane orientation of the films (200 nm thick) were investigated by x-ray diffraction techniques including ω and φ scans and pole figures. The IBAD YSZ and CeO2 films have a (111) pole in the ion beam direction with a full width at half maximum, FWHM = 24 - 30 deg; the CeO2/YSZ bilayer is similarly aligned with FWHM = 32 deg

  9. Memory resistive switching in CeO2-based film microstructures patterned by a focused ion beam

    International Nuclear Information System (INIS)

    Heteroepitaxial CeO2 (80 nm)/La0.5Sr0.5CoO3 (500 nm) film structure has been pulsed laser deposited on a sapphire substrate. The Ag/CeO2 microjunctions patterned by a focused ion beam on a La0.5Sr0.5CoO3 film exhibit reproducible reversible switching between a high resistance state (OFF) with insulating properties and a semiconducting or metallic low resistance state (ON) with resistance ratios up to 104. The influence of micro-scaling and defects formed at the cell boundaries during etching on its electrical characteristics has been analyzed. The appearance of a switching channel at the moment of the electrical forming, responsible for the memory effect, has been proved, along with a mechanism of a self-healing electrical breakdown. - Highlights: • Ag/CeO2/La0.5Sr0.5CoO3 microstructures were patterned by a focused ion beam. • Reproducible memory resistive switching was discovered in Ag/CeO2 microjunctions. • Micro-scaling affects electrical characteristics of Ag/CeO2 microjunctions. • A mechanism of a self-healing breakdown was discovered

  10. Effects of Substrate Temperatures on the Structure and UV-shielding Properties of TiO2-CeO2 Films Deposited on Glass by Radio-frequency Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qingnan; NI Jiamiao; ZHANG Naizhi; ZHAO Xiujian; JIANG Hong; WANG Guirong

    2005-01-01

    TiO2-CeO2 films were deposited on soda-lime glass substrates at varied substrate temperatures by rf magnetron sputtering using 40% molar TiO2- 60% molar CeO2 ceramic target in Ar: O2 = 95: 5 atmosphere. The structure, surface composition, UV-visible spectra of the films were measured by scanning electron microscopy and X- ray diffraction, and X- ray photoelectron spectroscopy, respectively. The experimental results show that the films are amorphous, there are only Ti4+ and Ce4+ on the surface of the films, the obtained TiO2-CeO2 films show a good uniformity and high densification, and the films deposited on the glass can shield ultraviolet light without significant absorption of visible light, the films deposited on substrates at room temperature and 220 ℃ absorb UV effectively.

  11. Thin films

    International Nuclear Information System (INIS)

    This volume is a compilation of papers presented at the 1990 Spring Meeting of the Materials Research Society in a symposium entitled Thin Films: Stresses and Mechanical Properties II. As indicated by the title, the symposium was the second in a series, the first of which was held at the Fall Meeting in 1988. The importance of thin film mechanical properties is now recognized to the extent that basic characterization techniques such as microindentation and thin film stress measurement are performed routinely, and new characterization techniques are being developed on a daily basis. Many of the papers in the symposium dealt with the developments in these characterization methods and their application to a broad spectrum of materials such as compositionally modulated structures, ion implanted materials, optical coatings, and the numerous metals, ceramics and organics used in semiconductor device manufacture

  12. Influence of the Incorporation of CeO2 Nanoparticles on the Ion Exchange Behavior of Dodecylsulfate Doped Polypyrrole Films: Ac-Electrogravimetry Investigations

    OpenAIRE

    Benmouhoub, Chabba; Agrisuelas, Jeronimo; Benbrahim, N.; Pillier, Francoise; Gabrielli, Claude; Kadri, A.; Pailleret, Alain; Perrot, Hubert; Sel, Ozlëm

    2014-01-01

    Cerium oxide (CeO2) nanoparticles (NPs) possessing defined size and crystallinity have been synthe-sised by a co-precipitation method. The effect of several parameters, such as the nature of the solventand the calcination process, on the crystallite size was studied by XRD, TEM and BET methods. TheseCeO2nanoparticles were then incorporated in dodecylsulfate (DS) doped PPy films during their elec-trodeposition in potentiodynamic conditions in order to produce PPy-DS/CeO2NPs nanocomposite thinf...

  13. Thin Films

    Czech Academy of Sciences Publication Activity Database

    Šolcová, Olga

    Maribor: Univerza v Mariboru, 2013. [Nanofuture. Maribor (SI), 03.02.2013-07.02.2013] R&D Projects: GA TA ČR TA01020804 Institutional support: RVO:67985858 Keywords : sol-gel methods * thin films * nannomaterials Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  14. Preparation and Characterization of Graphite Powder Covered with CeO2

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In order to improve the wetting properties of graphite with Al melt and reduce the oxidation of the graphite, by which the segregation of components during the liquid-stir-casting process could be prevented. In this paper, a uniform thin nano-film of CeO2, about 20 nm thick, was successfully prepared onto graphite powder surface by heterogeneous nucleation process. The results show that an obvious chemical reaction did exit between CeO2 film and graphite with the formation of Ce-O-C bond, leading to a shift of the binding energy of C and Ce. The cover with CeO2 film illustrates a distinct change of surface state of graphite with a decrease of angle of contact.

  15. Morphology, structural properties and reducibility of size-selected CeO2−x nanoparticle films

    Directory of Open Access Journals (Sweden)

    Maria Chiara Spadaro

    2015-01-01

    Full Text Available Non-stoichiometric ceria nanoparticles (NPs were obtained by a gas aggregation source with a magnetron and were mass-selected with a quadrupole mass filter. By varying magnetron power, Ar gas flow, and the length of the aggregation tube, NPs with an average diameter of 6, 9, and 14 nm were synthesized and deposited onto a substrate, thus obtaining NP films. The morphology of the films was studied with scanning electron microscopy, while high resolution transmission electron microscopy was used to gain a deeper insight into the atomic structure of individual NPs. By using X-ray photoelectron spectroscopy we analyzed the degree of reduction of the NPs of different diameters, before and after thermal treatments in vacuum (reduction cycle and in O2 atmosphere (oxidation cycle at different temperatures. From this analysis we inferred that the size is an important parameter only at intermediate temperatures. As a comparison, we evaluated the reducibility of an ultra-thin ceria film with the same surface to volume ratio as the 9 nm diameter NPs film, observing that NPs are more reducible than the ceria film.

  16. Laser assisted modification and chemical metallization of electron-beam deposited ceria thin films

    International Nuclear Information System (INIS)

    Excimer laser processing is applied for tailoring the surface morphology and phase composition of CeO2 ceramic thin films. E-beam evaporation technique is used to deposit samples on stainless steel and silicate glass substrates. The films are then irradiated with ArF* excimer laser pulses under different exposure conditions. Scanning electron microscopy, optical spectrophotometry, X-ray diffractometry and EDS microanalysis are used to characterize the non-irradiated and laser-processed films. Upon UV laser exposure there is large increase of the surface roughness that is accompanied by photo-darkening and ceria reduction. It is shown that the laser induced changes in the CeO2 films facilitate the deposition of metal nano-aggregates in a commercial copper electroless plating bath. The significance of laser modification as a novel approach for the production of CeO2 based thin film catalysts is discussed.

  17. Variations in the structural, optical and electrochemical properties of CeO2-TiO2 films as a function of TiO2 content

    International Nuclear Information System (INIS)

    Alcohol based sols of cerium chloride (CeCl3.7H2O) and titanium propoxide (Ti(OPr)4) in ethanol mixed in different mole ratios have yielded mixed oxide films on densification at 500 deg. C. The reversibility of the intercalation/deintercalation reactions has shown electrochemical stability of the films. Addition of TiO2 in an equivalent mole ratio manifests in producing highly transparent films with appreciable ion storage capacity. The electrochemical studies have revealed the significant role of TiO2 in controlling the ion storage capacity of the films, as it tends to induce the disorder. In addition, the films prepared from an aged sol are observed to exhibit a much higher ion storage capacity than the films deposited using the as-prepared sol. The X-ray photoelectron spectroscopic studies have provided information on the variation of Ce4+/Ce3+ ratio as a function of increased TiO2 content in the films. This study has led to a better understanding of the increased ion storage capacity with the increased TiO2 proportion. The transmission electron microscopic study has demonstrated the presence of CeO2 nanograins even in films, which are amorphous to X-rays. Elucidation of the structural, optical and electrochemical features of the films has yielded information on aspects relevant to their usage in transmissive electrochromic devices. The films have been found to exhibit properties that can find application as counter electrode in electrochromic smart windows in which they are able to retain their transparency under charge insertion, high enough for practical uses. Also, the fastest coloration-bleaching kinetics for the primary electrochromic electrode (WO3) working in combination with Ce/Ti (1:1) electrode stimulates the use of latter in electrochromic windows (ECWs)

  18. Variations in the structural, optical and electrochemical properties of CeO 2-TiO 2 films as a function of TiO 2 content

    Science.gov (United States)

    Verma, Amita; Joshi, Amish G.; Bakhshi, A. K.; Shivaprasad, S. M.; Agnihotry, S. A.

    2006-05-01

    Alcohol based sols of cerium chloride (CeCl 3·7H 2O) and titanium propoxide (Ti(OPr) 4) in ethanol mixed in different mole ratios have yielded mixed oxide films on densification at 500 °C. The reversibility of the intercalation/deintercalation reactions has shown electrochemical stability of the films. Addition of TiO 2 in an equivalent mole ratio manifests in producing highly transparent films with appreciable ion storage capacity. The electrochemical studies have revealed the significant role of TiO 2 in controlling the ion storage capacity of the films, as it tends to induce the disorder. In addition, the films prepared from an aged sol are observed to exhibit a much higher ion storage capacity than the films deposited using the as-prepared sol. The X-ray photoelectron spectroscopic studies have provided information on the variation of Ce 4+/Ce 3+ ratio as a function of increased TiO 2 content in the films. This study has led to a better understanding of the increased ion storage capacity with the increased TiO 2 proportion. The transmission electron microscopic study has demonstrated the presence of CeO 2 nanograins even in films, which are amorphous to X-rays. Elucidation of the structural, optical and electrochemical features of the films has yielded information on aspects relevant to their usage in transmissive electrochromic devices. The films have been found to exhibit properties that can find application as counter electrode in electrochromic smart windows in which they are able to retain their transparency under charge insertion, high enough for practical uses. Also, the fastest coloration-bleaching kinetics for the primary electrochromic electrode (WO 3) working in combination with Ce/Ti (1:1) electrode stimulates the use of latter in electrochromic windows (ECWs).

  19. Spray deposited CeO2–TiO2 counter electrode for electrochromic devices

    Indian Academy of Sciences (India)

    A K Bhosale; S R Kulal; V M Gurame; P S Patil

    2015-04-01

    Optically passive thin films of CeO2–TiO2 mixed oxides with molar ratio of Ce/Ti of 0.05 were deposited by the spray pyrolysis technique (SPT) on a glass and fluorine-doped tin oxide (FTO)-coated glass substrates. Precursor solution containing cerium nitrate hexahydrate (Ce(NO3)2·6H2O) and titanium tetraiso-propoxide (Ti(OiPr)4) having different volumetric proportions (0–5 vol% of Ti) in methanol were used. These films were characterized for structural, morphological, molecular, optical, electrochromic and colourimetric analysis. CeO2–TiO2 films deposited at 400° C were found to be polycrystalline with cubic fluorite crystal structure. Transformation from polycrystalline to amorphous phase was observed with increasing TiO2 content. The band centred at 539 cm−1 is assigned to Ce–O stretching vibration and the two medium intensity bands assigned to (Ti–O) and (Ti–O–Ti) stretching modes at 798 and 451 cm−1, which confirms the mixed CeO2 and TiO2 phases. The band gap energy decreases (g) from 3.45 eV for pristine CeO2 to 2.98–3.09 eV for CeO2–TiO2 films. The ion storage capacity (ISC) of CeO2–TiO2 thin film with 3 vol% Ti (Ce–Ti3 sample) was found to be 26 mC cm−2 and electrochemical stability up to 30,000 cycles in 0.5 M LiClO4-PC electrolyte. The optically passive behaviour of CeO2–TiO2 thin film is confirmed by its negligible transmission modulation ( ∼ 2.5%) upon Li+ ion insertion/extraction, irrespective of the extent of Li+ ion intercalation. The optical modulation of sputter deposited electrochromic WO3 thin film was found to be enhanced from 56 to 61% with rapid increase in colouration efficiency (CE) from 42 to 231 cm2 C−1 when CeO2–TiO2 is coupled as a counter electrode with WO3 in an electrochromic device (ECD). On reduction of WO3 thin film with CeO2–TiO2 as counter electrode, the CIELAB 1931 2° colour space coordinates show the transition from colourless to the deep blue state (* = 88.07, * = −2.37, * = 24.59 and

  20. Direct electrochemistry of myoglobin in a layer-by-layer film on an ionic liquid modified electrode containing CeO2 nanoparticles and hyaluronic acid

    International Nuclear Information System (INIS)

    We describe an ionic liquid modified electrode (CPE-IL) for sensing hydrogen peroxide (HP) that was modified by the layer-by-layer technique with myoglobin (Mb). In addition, the surface of the electrode was modified with CeO2 nanoparticles (nano-CeO2) and hyaluronic acid. UV-vis and FTIR spectroscopy confirmed that Mb retains its native structure in the composite film. Scanning electron microscopy showed that the nano-CeO2 closely interact with Mb to form an inhomogeneously distributed film. Cyclic voltammetry reveals a pair of quasi-reversible redox peaks of Mb, with the cathodic peak at -0. 357 V and the anodic peak at -0. 269 V. The peak separation (ΔEp) and the formal potential (Eσ) are 88 mV and -0. 313 V (vs. Ag/AgCl), respectively. The Mb immobilized in the modified electrode displays an excellent electrocatalytic activity towards HP in the 0. 6 to 78. 0 μM concentration range. The limit of detection is 50 nM (S/N = 3), and then the Michaelis-Menten constant is 71. 8 μM. We believe that such a composite film has potential to further investigate other redox proteins and in the fabrication of third-generation biosensors. (author)

  1. Thin Films

    Directory of Open Access Journals (Sweden)

    M. Benmouss

    2003-01-01

    the optical absorption are consistent with the film color changes. Finally, the optical and electrochromic properties of the films prepared by this method are compared with those of our sputtered films already studied and with other works.

  2. Surface and Interface Properties of 10–12 Unit Cells Thick Sputter Deposited Epitaxial CeO2 Films

    Directory of Open Access Journals (Sweden)

    L. V. Saraf

    2008-01-01

    Full Text Available Ultrathin and continuous epitaxial films with relaxed lattice strain can potentially maintain more of its bulk physical and chemical properties and are useful as buffer layers. We study surface, interface, and microstructural properties of ultrathin (∼10–12 unit cells thick epitaxial ceria films grown on single crystal YSZ substrates. The out-of -plane and in-plane lattice parameters indicate relaxation in the continuous film due to misfit dislocations seen by high-resolution transmission electron microscopy (HRTEM and substrate roughness of ∼1-2 unit cells, confirmed by atomic force microscopy and HRTEM. A combination of secondary sputtering, lattice mismatch, substrate roughness, and surface reduction creating secondary phase was likely the cause of surface roughness which should be reduced to a minimum level for effective use of it as buffer layers.

  3. Synthesis of Cerium Dioxide High-k Thin Films as a Gate Dielectric in MOS Capacitor

    OpenAIRE

    Anil G. Khairnar; Y.S. Mhaisagar; A.M. Mahajan

    2013-01-01

    In the present study, the Al/CeO2 / p-Si MOS capacitor was fabricated by depositing the Aluminium (Al) metal layer by thermal evaporation technique on sol-gel derived CeO2 high-k thin films on p-Si substrate. The deposited CeO2 films were characterized by Ellipsometer to study the refractive index that is determined to be 3.62. The FTIR analysis was carried out to obtain chemical bonding characteristics. Capacitance-voltage measurements of Al/CeO2 /p-Si MOS capacitor were carried out to deter...

  4. Sn-CeO2 thin films prepared by rf magnetron sputtering: XPS and SIMS study

    International Nuclear Information System (INIS)

    Sn addition in the CeO2 thin film by simultaneous Sn metal and cerium oxide magnetron sputtering causes growth of Ce3+ rich films whilst pure cerium oxide sputtering provides stoichiometric CeO2 layers. Ce4+ → Ce3+ conversion is explained by a charge transfer from Sn atoms to unoccupied orbital Ce 4f0 of cerium oxide by forming Ce 4f1 state. XPS and SIMS revealed a formation of a new chemical Ce(Sn)+ state, which belongs to SnCeO2 species.

  5. Ferromagnetism induced by oxygen and cerium vacancies above the percolation limit in CeO2

    Science.gov (United States)

    Fernandes, V.; Schio, P.; de Oliveira, A. J. A.; Ortiz, W. A.; Fichtner, P.; Amaral, L.; Graff, I. L.; Varalda, J.; Mattoso, N.; Schreiner, W. H.; Mosca, D. H.

    2010-06-01

    We studied the structural, chemical and magnetic properties of non-doped ceria (CeO2) thin films electrodeposited on silicon substrates. Experimental results confirm that the observed room temperature ferromagnetism is driven by both cerium and oxygen vacancies. We investigated ceria films presenting vacancy concentrations well above the percolation limit. Irradiation experiments with neon ions were employed to generate highly oxygen defective CeO2 - δ structures. X-ray photoelectron spectroscopy and x-ray absorption near-edge structure spectroscopy were used to estimate the concentration of Ce3 + sites in the films, which can reach up to 50% of Ce3 + replacing Ce4 + , compared to a stoichiometric CeO2 structure. Despite the increment of structural disorder, we observe that the saturation magnetization continuously increases with Ce3 + concentration. Our experiments demonstrate that the ferromagnetism observed in ceria thin films, highly disordered and oxygen-deficient, preserving the fluorite-type structure only in a nanometer scale, remains intrinsically stable at room temperature.

  6. Ferromagnetism induced by oxygen and cerium vacancies above the percolation limit in CeO2

    International Nuclear Information System (INIS)

    We studied the structural, chemical and magnetic properties of non-doped ceria (CeO2) thin films electrodeposited on silicon substrates. Experimental results confirm that the observed room temperature ferromagnetism is driven by both cerium and oxygen vacancies. We investigated ceria films presenting vacancy concentrations well above the percolation limit. Irradiation experiments with neon ions were employed to generate highly oxygen defective CeO2-δ structures. X-ray photoelectron spectroscopy and x-ray absorption near-edge structure spectroscopy were used to estimate the concentration of Ce3+ sites in the films, which can reach up to 50% of Ce3+ replacing Ce4+, compared to a stoichiometric CeO2 structure. Despite the increment of structural disorder, we observe that the saturation magnetization continuously increases with Ce3+ concentration. Our experiments demonstrate that the ferromagnetism observed in ceria thin films, highly disordered and oxygen-deficient, preserving the fluorite-type structure only in a nanometer scale, remains intrinsically stable at room temperature.

  7. Comparative study of structural, optical and impedance measurements on V2O5 and V-Ce mixed oxide thin films

    International Nuclear Information System (INIS)

    Vanadium pentoxide (V2O5) and Vanadium-Cerium mixed oxide thin films at different molar ratios of V2O5 and CeO2 have been deposited at 200 W rf power by rf planar magnetron sputtering in pure argon atmosphere. The structural and optical properties were studied by taking X-ray diffraction and transmittance and absorption spectra respectively. The amorphous thin films show an increase in transmittance and optical bandgap with increase in CeO2 content in as-prepared thin films. The impedance measurements for as-deposited thin films show an increase in electrical conductivity with increase in CeO2 material

  8. Pyrolyzed thin film carbon

    Science.gov (United States)

    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.

  9. Thin film processes II

    CERN Document Server

    Kern, Werner

    1991-01-01

    This sequel to the 1978 classic, Thin Film Processes, gives a clear, practical exposition of important thin film deposition and etching processes that have not yet been adequately reviewed. It discusses selected processes in tutorial overviews with implementation guide lines and an introduction to the literature. Though edited to stand alone, when taken together, Thin Film Processes II and its predecessor present a thorough grounding in modern thin film techniques.Key Features* Provides an all-new sequel to the 1978 classic, Thin Film Processes* Introduces new topics, and sever

  10. Engineered interfaces and nano-scale thin films for solid oxide fuel cell electrolytes

    Science.gov (United States)

    Nandasiri, Manjula I.

    Solid state electrolytes with high oxygen ionic conductivity at low temperatures are required to develop cost effective and efficient solid oxide fuel cells. This study investigates the influence of engineered interfaces on the oxygen ionic conductivity of nano-scale multilayer thin film electrolytes. The epitaxial Sm2O3 doped CeO2 (SDC) and Sc2O3 stabilized ZrO2 (ScSZ) are selected as the alternative layers for the proposed multilayer thin film electrolyte based on the optimum structural, chemical, and electrical properties reported in the previous studies. The epitaxial SDC(111)/ScSZ(111) multilayer thin films are grown on high purity Al2O3(0001) substrates by oxygen-plasma assisted molecular beam epitaxy. Prior to the deposition of multilayers, the growth parameters are optimized for epitaxial CeO 2, ZrO2, SDC, and ScSZ thin films. The epitaxial orientation and surface morphology of CeO2 thin films shows dependency on the growth rate. Epitaxial CeO2(111) is obtained at relatively high growth rates (>9 A/min) at a substrate temperature of 650°C and an oxygen partial pressure of 2 x 10 -5 Torr. The same growth parameters are used for the deposition of ZrO2 thin films. ZrO2 exhibits both monoclinic and cubic phases, which is stabilized in the cubic structure by doping with Sc 2O3. The Sm and Sc evaporation rates are varied during the growth to obtain thin films of 15 mol % SmO1.5 doped CeO2 and 20 mol % ScO1.5 stabilized ZrO2, respectively. The SDC/ScSZ multilayer thin films are grown using the same growth parameters by varying the number of layers. The SDC/ScSZ multilayer thin films show significant enhancement in the oxygen ionic conductivity in comparison to single layer SDC and ScSZ thin films. The increase in the oxygen ionic conductivity with the increase in number of layers can be attributed to lattice mismatch induced ionic conductivity along the interfaces. The 8-layer film exhibits the maximum oxygen ionic conductivity with one order of magnitude

  11. Deposition of CeO 2/YSZ buffer layer on Hastelloy substrates for MOD process of YBa 2Cu 3O 7- x film

    Science.gov (United States)

    Fuji, Hiroshi; Honjo, Tetsuji; Nakamura, Yuichi; Izumi, Teruo; Takeshi, Araki; Hirabayashi, Izumi; Shiohara, Yuh; Iijima, Yasuhiro; Takeda, Kaoru

    2001-08-01

    Trifluoroacetate metalorganic deposition (TFA-MOD) process is expected as a low cost process for mass production of coated conductors because it is a non-vacuum process. In order to apply the technique to fabrication of coated conductors, suitable buffer layers have to be considered to achieve a high orientation of superconducting layer and prevention of the reaction with metal substrate. The combination of CeO 2 on IBAD-YSZ is considered as an effective buffer for TFA-MOD process expecting to satisfy a high acid resistivity and high crystal grain alignment. The CeO 2 buffer layer was deposited on IBAD-YSZ/Hastelloy substrates by RF magnetron sputtering. From XRD analysis, the CeO 2 buffer layer showed very good in-plane alignment on YSZ-IBAD buffer layer. In a holding time of 1 h, the suitable maximum heat treatment temperature was found to be from 750°C to 775°C for TFA-Y123 on metal substrate. The Jc- B property of Y123 on CeO 2/YSZ/Hastelloy shows the Jc values of 1.4 MA/cm 2 at 77.3 K, 0 T and more than 10 5 A/cm 2 at 77.3 K, 2 T. The high performance under high magnetic field was confirmed.

  12. Collective magnetic response of CeO2 nanoparticles

    Science.gov (United States)

    Coey, Michael; Ackland, Karl; Venkatesan, Munuswamy; Sen, Siddhartha

    2016-07-01

    The magnetism of nanoparticles and thin films of wide-bandgap oxides that include no magnetic cations is an unsolved puzzle. Progress has been hampered by both the irreproducibility of much of the experimental data, and the lack of any generally accepted theoretical explanation. The characteristic signature is a virtually anhysteretic, temperature-independent magnetization curve that saturates in an applied field that is several orders of magnitude greater than the magnetization. It would seem as if a tiny volume fraction, temperature-independent magnetization curve and its doping and dispersion dependence, based on a length scale of 300 nm that corresponds to the wavelength of a maximum in the ultraviolet absorption spectrum of the magnetic CeO2 nanoparticles. The coherent domains occupy roughly 10% of the sample volume.

  13. Ceramic Composite Thin Films

    Science.gov (United States)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  14. Preparation and Characterization of CeO2/YSZ/CeO2 Buffer Layers for YBCO Coated Conductors

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    CeO2 seed layer was deposited on rolling-assisted biaxially textured metal substrates by direct-current (DC) magnetron reactive sputtering. The effect of deposition temperature on epitaxial orientation of CeO2 thin films was examined. High quality CeO2 layers were achieved at deposition temperature from 750℃ to 850℃.Subsequently yttria-stabilized zirconia (YSZ) and CeO2 films were deposited to complete the buffer layer structure via the same process. The best samples exhibited a highly biaxial texture, as indicated by FWHM (full width half maximum) values in the range of 4°-5°, and 2°-4° for in-plane and out-of-plane orientations,respectively. Secondary ion mass spectrometer analysis confirmed the effective prevention of buffer layer against Ni and W metal interdiffusion. Atomic force microscope observations revealed a smooth, dense and crack-free surface morphology, which provided themselves as the good buffer structure to the YBa2Cu3O7-δ(YBCO) coated conductors.

  15. Sol–gel deposited ceria thin films as gate dielectric for CMOS technology

    Indian Academy of Sciences (India)

    Anil G Khairnar; Ashok M Mahajan

    2013-04-01

    In this work, cerium oxide thin films were prepared using cerium chloride heptahydrate, ethanol and citric acid as an additive by sol–gel spin-coating technique and further characterized to study the various properties. Chemical composition of deposited films has been analysed by FTIR which shows existence of CeO2. The samples have been optically characterized using ellipsometry to find refractive index of 2.18 and physical thickness which is measured to be 5.56 nm. MOS capacitors were fabricated by depositing aluminum (Al) metal using the thermal evaporation technique on the top of CeO2 thin films. Capacitance–voltage measurement was carried out to calculate the dielectric constant, flat-band voltage shift of 18.92, 0.3–0.5V, respectively and conductance–voltage study was carried out to determine the Dit of 1.40 × 1013 eV-1 cm-2 at 1MHz.

  16. Carbon thin film thermometry

    Science.gov (United States)

    Collier, R. S.; Sparks, L. L.; Strobridge, T. R.

    1973-01-01

    The work concerning carbon thin film thermometry is reported. Optimum film deposition parameters were sought on an empirical basis for maximum stability of the films. One hundred films were fabricated for use at the Marshall Space Flight Center; 10 of these films were given a precise quasi-continuous calibration of temperature vs. resistance with 22 intervals between 5 and 80 K using primary platinum and germanium thermometers. Sensitivity curves were established and the remaining 90 films were given a three point calibration and fitted to the established sensitivity curves. Hydrogen gas-liquid discrimination set points are given for each film.

  17. Cerium Dioxide Thin Films Using Spin Coating

    Directory of Open Access Journals (Sweden)

    D. Channei

    2013-01-01

    Full Text Available Cerium dioxide (CeO2 thin films with varying Ce concentrations (0.1 to 0.9 M, metal basis were deposited on soda-lime-silica glass substrates using spin coating. It was found that all films exhibited the cubic fluorite structure after annealing at 500°C for 5 h. The laser Raman microspectroscopy and GAXRD analyses revealed that increasing concentrations of Ce resulted in an increase in the degree of crystallinity. FIB and FESEM images confirmed the laser Raman and GAXRD analyses results owing to the predicted increase in film thickness with increasing Ce concentration. However, porosity and shrinkage (drying cracking of the films also increased significantly with increasing Ce concentrations. UV-VIS spectrophotometry data showed that the transmission of the films decreased with increasing Ce concentrations due to the increasing crack formation. Furthermore, a red shift was observed with increasing Ce concentrations, which resulted in a decrease in the optical indirect band gap.

  18. Biomimetic thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graff, G.L.; Campbell, A.A.; Gordon, N.R.

    1995-05-01

    The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

  19. Synthesis of Cerium Dioxide High-k Thin Films as a Gate Dielectric in MOS Capacitor

    Directory of Open Access Journals (Sweden)

    Anil G. Khairnar

    2013-07-01

    Full Text Available In the present study, the Al/CeO2 / p-Si MOS capacitor was fabricated by depositing the Aluminium (Al metal layer by thermal evaporation technique on sol-gel derived CeO2 high-k thin films on p-Si substrate. The deposited CeO2 films were characterized by Ellipsometer to study the refractive index that is determined to be 3.62. The FTIR analysis was carried out to obtain chemical bonding characteristics. Capacitance-voltage measurements of Al/CeO2 /p-Si MOS capacitor were carried out to determine the dielectric constant, equivalent oxide thickness (EOT and flat band shift (VFB for the deposited CeO2 film of 16.22, 1.62 nm and 0.7 V respectively. The conductance voltage curve was used to determine the interface trap density (Dit at the CeO2 / p-Si interface that is calculated to be 1.29 × 1013 cm – 2 eV – 1 for measurement frequency of 500 kHz.

  20. Elaboration and characterization of thin solid films containing cerium

    Science.gov (United States)

    Hamdi, S.; Guerfi, S.; Siab, R.

    2009-11-01

    Cerium oxide films are widely studied as a promising alternative to Cr(VI) based pre-treatments for the corrosion protection of different metals and alloys. Cathodic electrodeposition of Cerium containing thin films was realised on TA6V substrates from a Ce(NO3)3, 6H2O and mixed water-ethyl alcohol solutions at 0.01 M. Experimental conditions to obtain homogeneous and crack free thin films were determined. The deposited cerium quantity appears proportional to the quantity of electricity used, as indicated by the Faraday law. Subsequent thermal treatment lead to a CeO2 coating, expected to provide an increase of TA6V oxidation resistance at high temperatures. The deposits were characterized by differential scanning calorimetry (DSC), optical and scanning electron microscopies.

  1. Thin film device applications

    CERN Document Server

    Kaur, Inderjeet

    1983-01-01

    Two-dimensional materials created ab initio by the process of condensation of atoms, molecules, or ions, called thin films, have unique properties significantly different from the corresponding bulk materials as a result of their physical dimensions, geometry, nonequilibrium microstructure, and metallurgy. Further, these characteristic features of thin films can be drasti­ cally modified and tailored to obtain the desired and required physical characteristics. These features form the basis of development of a host of extraordinary active and passive thin film device applications in the last two decades. On the one extreme, these applications are in the submicron dimensions in such areas as very large scale integration (VLSI), Josephson junction quantum interference devices, magnetic bubbles, and integrated optics. On the other extreme, large-area thin films are being used as selective coatings for solar thermal conversion, solar cells for photovoltaic conver­ sion, and protection and passivating layers. Ind...

  2. Oxygen vacancy-assisted coupling and enolization of acetaldehyde on CeO2(111).

    Science.gov (United States)

    Calaza, Florencia C; Xu, Ye; Mullins, David R; Overbury, Steven H

    2012-10-31

    The temperature-dependent adsorption and reaction of acetaldehyde (CH(3)CHO) on a fully oxidized and a highly reduced thin-film CeO(2)(111) surface have been investigated using a combination of reflection-absorption infrared spectroscopy (RAIRS) and periodic density functional theory (DFT+U) calculations. On the fully oxidized surface, acetaldehyde adsorbs weakly through its carbonyl O interacting with a lattice Ce(4+) cation in the η(1)-O configuration. This state desorbs at 210 K without reaction. On the highly reduced surface, new vibrational signatures appear below 220 K. They are identified by RAIRS and DFT as a dimer state formed from the coupling of the carbonyl O and the acyl C of two acetaldehyde molecules. This dimer state remains up to 400 K before decomposing to produce another distinct set of vibrational signatures, which are identified as the enolate form of acetaldehyde (CH(2)CHO¯). Furthermore, the calculated activation barriers for the coupling of acetaldehyde, the decomposition of the dimer state, and the recombinative desorption of enolate and H as acetaldehyde are in good agreement with previously reported TPD results for acetaldehyde adsorbed on reduced CeO(2)(111) [Chen et al. J. Phys. Chem. C 2011, 115, 3385]. The present findings demonstrate that surface oxygen vacancies alter the reactivity of the CeO(2)(111) surface and play a crucial role in stabilizing and activating acetaldehyde for coupling reactions. PMID:23020248

  3. Ferroelectric thin films

    International Nuclear Information System (INIS)

    The area of ferroelectric thin films has expanded rapidly recently with the advent of high quality multi-oxide deposition technology. Advances in thin film quality has resulted in the realization of new technologies not achievable through classical bulk ceramic processing techniques. An example of this progress is the co-processing of ferroelectric thin films with standard semiconductor silicon and GaAs integrated circuits for radiation hard, non-volatile memory products. While the development of this class of products is still embryonic, the forecasted market potential is rapidly out distancing the combined developmental effort. Historically the greatest use of bulk ferroelectric material has been in sensor technology, utilizing the pyroelectric and piezoelectric properties of the material. By comparison, a relatively small development effort has been reported for ferroelectric thin film senor technology, a field sure to provide exciting advances in the future. The papers in this proceedings volume were presented at the first symposium dedicated to the field of ferroelectric thin films held by the Materials Research Society at the Spring 1990 Meeting in San Francisco, CA, April 16-20, 1990. The symposium was designed to provide a comprehensive tutorial covering the newest advances of ferroelectric thin films, including material systems, new deposition techniques and physical, electrical and electro-optic characterization

  4. Superconducting and normal state transport properties of epitaxial 10 at.% Ca substituted YBCO thin films

    International Nuclear Information System (INIS)

    The improvement of the critical current density in YBCO coated conductor tapes necessarily concerns the study of grain boundary (GB) properties and the study of different pinning mechanisms involving both GB and the interior of the grain (IG). Recently, it has been proposed that the introduction of Ca substituting Y enhances J c in YBCO grain boundaries (GB). On the other hand enhanced correlated pinning, as observed in YBCO thin films grown on CeO2 buffered substrates, has been ascribed to elongated defects along the c-axis of the film. In order to evaluate the role of calcium and CeO2 buffer layer on the superconducting transport properties of YBCO films, critical current density measurements as a function of temperature, magnetic field and angle between magnetic field direction and c-axis of the film have been performed on epitaxial thin films of unsubstituted and 10 at.% Ca substituted YBCO grown on CeO2 buffered Al2O3 single crystal substrates. Results are compared with data obtained on 10 at.% Ca substituted YBCO grown on SrTiO3 single crystal substrate

  5. Evaporated VOx Thin Films

    Science.gov (United States)

    Stapinski, Tomasz; Leja, E.

    1989-03-01

    VOx thin films on glass were obtained by thermal evaporation of V205, powder. The structural investigations were carried out with the use of X-ray diffractometer. The electrical properties of the film were examined by means of temperature measurements of resistivity for the samples heat-treated in various conditions. Optical transmission and reflection spectra of VOX films of various composition showed the influence of the heat treatment.

  6. Heterogeneity in Polymer Thin Films

    OpenAIRE

    Kanaya, Toshiji; Inoue, Rintaro; Nishida, Koji

    2011-01-01

    In the last two decades very extensive studies have been performed on polymer thin films to reveal very interesting but unusual properties. One of the most interesting findings is the decrease in glass transition temperature Tg with film thickness in polystyrene (PS) thin film supported on Si substrate. Another interesting finding is apparent negative thermal expansivity in glassy state for thin films below ∼25 nm. In order to understand the unusual properties of polymer thin films we have st...

  7. Thin films and nanomaterials

    International Nuclear Information System (INIS)

    The objective of this book is to disseminate the most recent research in Thin Films, Nanomaterials, Corrosion and Metallurgy presented at the International Conference on Advanced Materials (ICAM 2011) held in PSG College of Technology, Coimbatore, India during 12-16 December 2011. The book is a compilation of 113 chapters written by active researchers providing information and critical insights into the recent advancements that have taken place. Important new applications are possible today in the fields of microelectronics, opto-electronics, metallurgy and energy by the application of thin films on solid surfaces. Recent progress in high vacuum technology and new materials has a remarkable effect in thin film quality and cost. This has led to the development of new single or multi-layered thin film devices with diverse applications in a multitude of production areas, such as optics, thermal barrier coatings and wear protections, enhancing service life of tools and to protect materials against thermal and atmospheric influence. On the other hand, thin film process techniques and research are strongly related to the basic research activities in nano technology, an increasingly important field with countless opportunities for applications due to the emergence of new properties at the nanoscale level. Materials and structures that are designed and fabricated at the nano scale level, offer the potential to produce new devices and processes that may enhance efficiencies and reduce costs in many areas, as photovoltaic systems, hydrogen storage, fuel cells and solar thermal systems. In the book, the contributed papers are classified under two sections i) thin films and ii) nanomaterials. The thin film section includes single or multi layer conducting, insulating or semiconducting films synthesized by a wide variety of physical or chemical techniques and characterized or analyzed for different applications. The nanomaterials section deals with novel or exciting materials

  8. Thin film photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Zweibel, K; Ullal, H S

    1989-05-01

    Thin films are considered a potentially attractive technological approach to making cost-effective electricity by photovoltaics. Over the last twenty years, many have been investigated and some (cadmium telluride, copper indium diselenide, amorphous silicon) have become leading candidates for future large-scale commercialization. This paper surveys the past development of these key thin films and gives their status and future prospects. In all cases, significant progress toward cost-effective PV electricity has been made. If this progress continues, it appears that thin film PV could provide electricity that is competitive for summer daytime peaking power requirements by the middle of the 1990s; and electricity in a range that is competitive with fossil fuel costs (i.e., 6 cents/kilowatt-hour) should be available from PV around the turn of the century. 22 refs., 9 figs.

  9. Thin film temperature sensor

    Science.gov (United States)

    Grant, H. P.; Przybyszewski, J. S.

    1980-01-01

    Thin film surface temperature sensors were developed. The sensors were made of platinum-platinum/10 percent rhodium thermocouples with associated thin film-to-lead wire connections and sputtered on aluminum oxide coated simulated turbine blades for testing. Tests included exposure to vibration, low velocity hydrocarbon hot gas flow to 1250 K, and furnace calibrations. Thermal electromotive force was typically two percent below standard type S thermocouples. Mean time to failure was 42 hours at a hot gas flow temperature of 1250 K and an average of 15 cycles to room temperature. Failures were mainly due to separation of the platinum thin film from the aluminum oxide surface. Several techniques to improve the adhesion of the platinum are discussed.

  10. Thin Film Microbatteries

    International Nuclear Information System (INIS)

    Thin film batteries are built layer by layer by vapor deposition. The resulting battery is formed of parallel plates, much as an ordinary battery construction, just much thinner. The figure (Fig. 1) shows an example of a thin film battery layout where films are deposited symmetrically onto both sides of a supporting substrate. The full stack of films is only 10 to 15 (micro)m thick, but including the support at least doubles the overall battery thickness. When the support is thin, the entire battery can be flexible. At least six companies have commercialized or are very close to commercializing such all-solid-state thin film batteries and market research predicts a growing market and a variety of applications including sensors, RFID tags, and smarter cards. In principle with a large deposition system, a thin film battery might cover a square meter, but in practice, most development is targeting individual cells with active areas less than 25 cm2. For very small battery areas, 2, microfabrication processes have been developed. Typically the assembled batteries have capacities from 0.1 to 5 mAh. The operation of a thin film battery is depicted in the schematic diagram (Fig. 2). Very simply, when the battery is allowed to discharge, a Li+ ion migrates from the anode to the cathode film by diffusing through the solid electrolyte. When the anode and cathode reactions are reversible, as for an intercalation compound or alloy, the battery can be recharged by reversing the current. The difference in the electrochemical potential of the lithium determines the cell voltage. Most of the thin films used in current commercial variations of this thin film battery are deposited in vacuum chambers by RF and DC magnetron sputtering and by thermal evaporation onto unheated substrates. In addition, many publications report exploring a variety of other physical and chemical vapor deposition processes, such as pulsed laser deposition, electron cyclotron resonance sputtering, and

  11. Thin film ceramic thermocouples

    Science.gov (United States)

    Gregory, Otto (Inventor); Fralick, Gustave (Inventor); Wrbanek, John (Inventor); You, Tao (Inventor)

    2011-01-01

    A thin film ceramic thermocouple (10) having two ceramic thermocouple (12, 14) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple (10) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

  12. Thin film metal-oxides

    CERN Document Server

    Ramanathan, Shriram

    2009-01-01

    Presents an account of the fundamental structure-property relations in oxide thin films. This title discusses the functional properties of thin film oxides in the context of applications in the electronics and renewable energy technologies.

  13. Thin films for material engineering

    Science.gov (United States)

    Wasa, Kiyotaka

    2016-07-01

    Thin films are defined as two-dimensional materials formed by condensing one by one atomic/molecular/ionic species of matter in contrast to bulk three-dimensional sintered ceramics. They are grown through atomic collisional chemical reaction on a substrate surface. Thin film growth processes are fascinating for developing innovative exotic materials. On the basis of my long research on sputtering deposition, this paper firstly describes the kinetic energy effect of sputtered adatoms on thin film growth and discusses on a possibility of room-temperature growth of cubic diamond crystallites and the perovskite thin films of binary compound PbTiO3. Secondly, high-performance sputtered ferroelectric thin films with extraordinary excellent crystallinity compatible with MBE deposited thin films are described in relation to a possible application for thin-film MEMS. Finally, the present thin-film technologies are discussed in terms of a future material science and engineering.

  14. Nanoparticulate cerium dioxide and cerium dioxide-titanium dioxide composite thin films on glass by aerosol assisted chemical vapour deposition

    International Nuclear Information System (INIS)

    Two series of composite thin films were deposited on glass by aerosol assisted chemical vapour deposition (AACVD)-nanoparticulate cerium dioxide and nanoparticulate cerium dioxide embedded in a titanium dioxide matrix. The films were analysed by a range of techniques including UV-visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy and energy dispersive analysis by X-rays. The AACVD prepared films showed the functional properties of photocatalysis and super-hydrophilicity. The CeO2 nanoparticle thin films displaying photocatalysis and photo-induced hydrophilicity almost comparable to that of anatase titania.

  15. Rare Earth Oxide Thin Films

    CERN Document Server

    Fanciulli, Marco

    2007-01-01

    Thin rare earth (RE) oxide films are emerging materials for microelectronic, nanoelectronic, and spintronic applications. The state-of-the-art of thin film deposition techniques as well as the structural, physical, chemical, and electrical properties of thin RE oxide films and of their interface with semiconducting substrates are discussed. The aim is to identify proper methodologies for the development of RE oxides thin films and to evaluate their effectiveness as innovative materials in different applications.

  16. Selective inorganic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, M.L.F.; Weisenbach, L.A.; Anderson, M.T. [Sandia National Laboratories, Albuquerque, NM (United States)] [and others

    1995-05-01

    This project is developing inorganic thin films as membranes for gas separation applications, and as discriminating coatings for liquid-phase chemical sensors. Our goal is to synthesize these coatings with tailored porosity and surface chemistry on porous substrates and on acoustic and optical sensors. Molecular sieve films offer the possibility of performing separations involving hydrogen, air, and natural gas constituents at elevated temperatures with very high separation factors. We are focusing on improving permeability and molecular sieve properties of crystalline zeolitic membranes made by hydrothermally reacting layered multicomponent sol-gel films deposited on mesoporous substrates. We also used acoustic plate mode (APM) oscillator and surface plasmon resonance (SPR) sensor elements as substrates for sol-gel films, and have both used these modified sensors to determine physical properties of the films and have determined the sensitivity and selectivity of these sensors to aqueous chemical species.

  17. Protein Thin Film Machines

    OpenAIRE

    Federici, Stefania; Oliviero, Giulio; Hamad-Schifferli, Kimberly; Bergese, Paolo

    2010-01-01

    We report the first example of microcantilever beams that are reversibly driven by protein thin film machines fuelled by cycling the salt concentration of the surrounding solution. We also show that upon the same salinity stimulus the drive can be completely reversed in its direction by introducing a surface coating ligand. Experimental results are throughout discussed within a general yet simple thermodynamic model.

  18. Thin film scintillators

    Science.gov (United States)

    McDonald, Warren; McKinney, George; Tzolov, Marian

    2015-03-01

    Scintillating materials convert energy flux (particles or electromagnetic waves) into light with spectral characteristic matching a subsequent light detector. Commercial scintillators such as yttrium aluminum garnet (YAG) and yttrium aluminum perovskite (YAP) are commonly used. These are inefficient at lower energies due to the conductive coating present on their top surface, which is needed to avoid charging. We hypothesize that nano-structured thin film scintillators will outperform the commercial scintillators at low electron energies. We have developed alternative thin film scintillators, zinc tungstate and zinc oxide, which show promise for higher sensitivity to lower energy electrons since they are inherently conductive. Zinc tungstate films exhibit photoluminescence quantum efficiency of 74%. Cathodoluminescence spectroscopy was applied in transmission and reflection geometries. The comparison between the thin films and the YAG and YAP commercial scintillators shows much higher light output from the zinc tungstate and zinc oxide at electron energies less than 5 keV. Our films were integrated in a backscattered electron detector. This detector delivers better images than an identical detector with commercial YAG scintillator at low electron energies. Dr. Nicholas Barbi from PulseTor LLC, Dr. Anura Goonewardene, NSF Grants: #0806660, #1058829, #0923047.

  19. Physics of thin films

    Energy Technology Data Exchange (ETDEWEB)

    Francombe, M.H. (Dept. of Physics, Univ. of Pittsburgh, Pittsburgh, PA (US)); Vossen, J.L. (John Vossen Associates, Technical and Scientific Consulting, Bridgewater, NJ (US))

    1992-01-01

    This book of Physics of Thin Films emphasizes two main technical themes. The first is essentially an extension of the topical thrust on Thin Films for Advance Electronic Devices, developed in Volume 15 of this series. The second deals primarily with the physical and mechanical behavior of films and the influence of these in relation to various applications. The first of the four articles in this volume, by Neelkanth G. Dhere, discusses high-transition-temperature (T{sub c}) superconducting films. Since their discovery in 1986, both world-wide research activity and published literature on high-T{sub c} oxide films have exploded at a phenomenal rate. In his treatment, the author presents an effective survey of the already vast literature on this subject, discusses the numerous techniques under development for the growth of these perovskite-related complex oxides, and describes their key properties and applications. In particular, factors affecting the epitaxial structure, critical current capability, and microwave conductivity in Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O based film compositions are evaluated in relation to their use at 77K. An overview of potential applications in a variety of microwave devices, wide-band optical detectors, SQUID-type high-sensitivity magnetometers, etc., is included.

  20. Physics of thin films

    International Nuclear Information System (INIS)

    This book of Physics of Thin Films emphasizes two main technical themes. The first is essentially an extension of the topical thrust on Thin Films for Advance Electronic Devices, developed in Volume 15 of this series. The second deals primarily with the physical and mechanical behavior of films and the influence of these in relation to various applications. The first of the four articles in this volume, by Neelkanth G. Dhere, discusses high-transition-temperature (Tc) superconducting films. Since their discovery in 1986, both world-wide research activity and published literature on high-Tc oxide films have exploded at a phenomenal rate. In his treatment, the author presents an effective survey of the already vast literature on this subject, discusses the numerous techniques under development for the growth of these perovskite-related complex oxides, and describes their key properties and applications. In particular, factors affecting the epitaxial structure, critical current capability, and microwave conductivity in Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O based film compositions are evaluated in relation to their use at 77K. An overview of potential applications in a variety of microwave devices, wide-band optical detectors, SQUID-type high-sensitivity magnetometers, etc., is included

  1. Thin film superconductor magnetic bearings

    Science.gov (United States)

    Weinberger, Bernard R.

    1995-12-26

    A superconductor magnetic bearing includes a shaft (10) that is subject to a load (L) and rotatable around an axis of rotation, a magnet (12) mounted to the shaft, and a stator (14) in proximity to the shaft. The stator (14) has a superconductor thin film assembly (16) positioned to interact with the magnet (12) to produce a levitation force on the shaft (10) that supports the load (L). The thin film assembly (16) includes at least two superconductor thin films (18) and at least one substrate (20). Each thin film (18) is positioned on a substrate (20) and all the thin films are positioned such that an applied magnetic field from the magnet (12) passes through all the thin films. A similar bearing in which the thin film assembly (16) is mounted on the shaft (10) and the magnet (12) is part of the stator (14) also can be constructed.

  2. Biomimetic thin film deposition

    Energy Technology Data Exchange (ETDEWEB)

    Rieke, P.R.; Graff, G.E.; Campbell, A.A.; Bunker, B.C.; Baskaran, S.; Song, L.; Tarasevich, B.J.; Fryxell, G.E.

    1995-09-01

    Biological mineral deposition for the formation of bone, mollusk shell and other hard tissues provides materials scientists with illustrative materials processing strategies. This presentation will review the key features of biomineralization and how these features can be of technical importance. We have adapted existing knowledge of biomineralization to develop a unique method of depositing inorganic thin films and coating. Our approach to thin film deposition is to modify substrate surfaces to imitate the proteins found in nature that are responsible for controlling mineral deposition. These biomimetic surfaces control the nucleation and growth of the mineral from a supersaturated aqueous solution. This has many processing advantages including simple processing equipment, environmentally benign reagents, uniform coating of highly complex shapes, and enhanced adherence of coating. Many different types of metal oxide, hydroxide, sulfide and phosphate materials with useful mechanical, optical, electronic and biomedical properties can be deposited.

  3. Thin film processes

    CERN Document Server

    Vossen, John L

    1978-01-01

    Remarkable advances have been made in recent years in the science and technology of thin film processes for deposition and etching. It is the purpose of this book to bring together tutorial reviews of selected filmdeposition and etching processes from a process viewpoint. Emphasis is placed on the practical use of the processes to provide working guidelines for their implementation, a guide to the literature, and an overview of each process.

  4. Handbook of thin film technology

    CERN Document Server

    Frey, Hartmut

    2015-01-01

    “Handbook of Thin Film Technology” covers all aspects of coatings preparation, characterization and applications. Different deposition techniques based on vacuum and plasma processes are presented. Methods of surface and thin film analysis including coating thickness, structural, optical, electrical, mechanical and magnetic properties of films are detailed described. The several applications of thin coatings and a special chapter focusing on nanoparticle-based films can be found in this handbook. A complete reference for students and professionals interested in the science and technology of thin films.

  5. Thin film mechanics

    Science.gov (United States)

    Cooper, Ryan C.

    This doctoral thesis details the methods of determining mechanical properties of two classes of novel thin films suspended two-dimensional crystals and electron beam irradiated microfilms of polydimethylsiloxane (PDMS). Thin films are used in a variety of surface coatings to alter the opto-electronic properties or increase the wear or corrosion resistance and are ideal for micro- and nanoelectromechanical system fabrication. One of the challenges in fabricating thin films is the introduction of strains which can arise due to application techniques, geometrical conformation, or other spurious conditions. Chapters 2-4 focus on two dimensional materials. This is the intrinsic limit of thin films-being constrained to one atomic or molecular unit of thickness. These materials have mechanical, electrical, and optical properties ideal for micro- and nanoelectromechanical systems with truly novel device functionality. As such, the breadth of applications that can benefit from a treatise on two dimensional film mechanics is reason enough for exploration. This study explores the anomylously high strength of two dimensional materials. Furthermore, this work also aims to bridge four main gaps in the understanding of material science: bridging the gap between ab initio calculations and finite element analysis, bridging the gap between ab initio calculations and experimental results, nanoscale to microscale, and microscale to mesoscale. A nonlinear elasticity model is used to determine the necessary elastic constants to define the strain-energy density function for finite strain. Then, ab initio calculations-density functional theory-is used to calculate the nonlinear elastic response. Chapter 2 focuses on validating this methodology with atomic force microscope nanoindentation on molybdenum disulfide. Chapter 3 explores the convergence criteria of three density functional theory solvers to further verify the numerical calculations. Chapter 4 then uses this model to investigate

  6. Effect of Oxide Buffer Layer on the Thermochromic Properties of VO2 Thin Films

    Science.gov (United States)

    Koo, Hyun; Xu, Lu; Ko, Kyeong-Eun; Ahn, Seunghyun; Chang, Se-Hong; Park, Chan

    2013-12-01

    VO2 thin films were deposited on soda lime glass substrates with ZnO, TiO2, SnO2, and CeO2 thin films applied as buffer layers between the VO2 films and the substrates in order to investigate the effect of buffer layer on the formation and the thermochromic properties of VO2 film. Buffer layers with thicknesses over 50 nm were found to affect the formation of VO2 film, which was confirmed by XRD spectra. By using ZnO, TiO2, and SnO2 buffer layers, monoclinic VO2 (VO2(M)) film was successfully fabricated on soda lime glass at 370 °C. On the contrary, films of VO2(B), which is known to have no phase transition near room temperature, were formed rather than VO2(M) when the film was deposited on CeO2 buffer layer at the same film deposition temperature. The excellent thermochromic properties of the films deposited on ZnO, TiO2, and SnO2 buffer layers were confirmed from the temperature dependence of electrical resistivity from room temperature to 80 °C. Especially, due to the tendency of ZnO thin film to grow with a high degree of preferred orientation on soda lime glass at low temperature, the VO2 film deposited on ZnO buffer layer exhibits the best thermochromic properties compared to those on other buffer layer materials used in this study. These results suggest that deposition of VO2 films on soda lime glass at low temperature with excellent thermochromic properties can be achieved by considering the buffer layer material having structural similarity with VO2. Moreover, the degree of crystallization of buffer layer is also related with that of VO2 film, and thus ZnO can be one of the most effective buffer layer materials.

  7. Polycrystalline thin film photovoltaic technology

    Energy Technology Data Exchange (ETDEWEB)

    Ullal, H.S.; Zweibel, K.; Mitchell, R.L.; Noufi, R.

    1991-03-01

    Low-cost, high-efficiency thin-film modules are an exciting photovoltaic technology option for generating cost-effective electricity in 1995 and beyond. In this paper we review the significant technical progress made in the following thin films: copper indium diselenide, cadmium telluride, and polycrystalline thin silicon films. Also, the recent US DOE/SERI initiative to commercialize these emerging technologies is discussed. 6 refs., 9 figs.

  8. Investigation on Silicon Thin Film Solar Cells

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The preparation, current status and trends are investigated for silicon thin film solar cells. The advantages and disadvantages of amorphous silicon thin film, polycrystalline silicon thin film and mono-crystalline silicon thin film solar cells are compared. The future development trends are pointed out. It is found that polycrystalline silicon thin film solar cells will be more promising for application with great potential.

  9. Pulsed laser deposition of YBCO thin films on IBAD-YSZ substrates

    International Nuclear Information System (INIS)

    High-quality YBa2Cu3O7-x (YBCO) films were fabricated on yttria-stabilized zirconia (YSZ)-buffered Hastelloy C276 substrates by pulsed laser deposition. YSZ was grown by ion-beam-assisted deposition. A thin (∼10 nm) CeO2 layer was deposited before the deposition of YBCO. The crystalline structure and biaxial texture of the YBCO film and the buffer layer were examined by x-ray diffraction 2θ-scan, φ-scan and pole-figure analysis. Epitaxial growth of the YBCO film on the buffer layer was observed. Full width at half maximum (FWHM) value of 7.4 deg. was measured from the φ-scan of YBCO(103). Raman spectroscopy showed compositional uniformity and phase integrity in the YBCO films. Surface morphologies of the YBCO films were examined by scanning electron microscopy. Comparative studies indicated that the CeO2 buffer layer significantly improves the structural alignment and superconducting properties of YBCO films. Tc = 90 K, with sharp transition, and transport Jc = 2.2 x 106 A cm-2 at 77 K in zero-external field were obtained on the 0.5 μm thick YBCO films. The dependence of Jc on the FWHM of the YBCO(103) φ-scan indicated that high Jc is associated with low FWHM

  10. Pulsed laser deposition of YBCO thin films on IBAD-YSZ substrates

    Science.gov (United States)

    Li, M.; Ma, B.; Koritala, R. E.; Fisher, B. L.; Venkataraman, K.; Balachandran, U.

    2003-01-01

    High-quality YBa2Cu3O7-x (YBCO) films were fabricated on yttria-stabilized zirconia (YSZ)-buffered Hastelloy C276 substrates by pulsed laser deposition. YSZ was grown by ion-beam-assisted deposition. A thin (approx10 nm) CeO2 layer was deposited before the deposition of YBCO. The crystalline structure and biaxial texture of the YBCO film and the buffer layer were examined by x-ray diffraction 2theta-scan, phi-scan and pole-figure analysis. Epitaxial growth of the YBCO film on the buffer layer was observed. Full width at half maximum (FWHM) value of 7.4° was measured from the phi-scan of YBCO(103). Raman spectroscopy showed compositional uniformity and phase integrity in the YBCO films. Surface morphologies of the YBCO films were examined by scanning electron microscopy. Comparative studies indicated that the CeO2 buffer layer significantly improves the structural alignment and superconducting properties of YBCO films. Tc = 90 K, with sharp transition, and transport Jc = 2.2 × 106 A cm-2 at 77 K in zero-external field were obtained on the 0.5 mum thick YBCO films. The dependence of Jc on the FWHM of the YBCO(103) phi-scan indicated that high Jc is associated with low FWHM.

  11. Electrodeposition of Ni-La2O3/CeO2 nanocomposite and its catalytic applications

    International Nuclear Information System (INIS)

    Ni-La2O3/CeO2 nanocomposite film was prepared by electrodeposition method. Nanosized La2O3(20-50 nm) and CeO2 (20-50 nm) particles were dispersed into a conventional watt's nickel electrolyte bath. Electrodeposited film was characterized by SEM, EDS, XRD and AFM. The resulting film was used as a cathode for hydrogen evolution reaction and it shows better catalytic activity. Microhardness, corrosion resistance studies, and catalytic activity towards methanol oxidation were also carried out. The synergism of La2O3 and CeO2 in nickel matrix significantly enhances the catalytic activities. (author)

  12. Frictional properties of CeO$_{2}$-Al$_{2}$O$_{3}$-ZrO$_{2}$ plasma-sprayed film under mixed and boundary lubricating conditions

    CERN Document Server

    Kita, H; Osumi, K; 10.2109/jcersj.112.615

    2004-01-01

    In order to find a counterpart for reducing the frictional coefficient of Al/sub 2/O/sub 3/-ZrO/sub 2/-CeO/sub 2/ plasma-sprayed film, the sliding properties in mixed and boundary lubricating conditions was investigated. It was found that combination of a CrN- coated cast iron pin and an Al/sub 2/O/sub 3/-ZrO/sub 2/-CeO/sub 2/ plasma sprayed plate provided the lowest frictional coefficient among several combinations chosen from practical materials. The coefficient of friction was much lower than that of the materials combination widely used for piston ring and cylinder liner. It was inferred that the combination of a pin made of hard materials with high density, a smooth surface such as CrN-coated cast iron and a porous plate can reduce the frictional coefficient because less sliding resistance is implemented and porosity retains oil.

  13. Effective thickness of CeO2 buffer layer for YBCO coated conductor by advanced TFA-MOD process

    International Nuclear Information System (INIS)

    YBCO films were fabricated on PLD-CeO2/IBAD-Gd2Zr2O7/Hastelloy substrates using the advanced TFA-MOD process. The effective thickness of the CeO2 buffer layer for obtaining high Ic was investigated in short samples of YBCO films. The CeO2 buffer layer was epitaxially grown on an IBAD-Gd2Zr2O7 template tape with 18 deg. of Δφ by a reel-to-reel PLD system. The in-plane grain alignment of PLD-CeO2 buffer layers rapidly improved with the thickness and saturated at a critical thickness of 0.8 μm. The size of CeO2 grains was about 1 μm at the saturated thickness of Δφ. YBCO films with the thickness of 1 μm were deposited by the TFA-MOD on the CeO2 buffer layer with different thickness films. Improvement of the CeO2 in-plane grain alignment resulted in increase of Ic. The Ic values of 250-290 A were obtained with the CeO2 layer thicker than 0.8 μm. The CeO2 thickness, at which the intensity ratio of the BaCeO3 was saturated, corresponded to the critical thickness. From the view points of achieving higher production rates and to obtain the CeO2 Δφ value of 5 deg. as well as considering the reaction between YBCO and CeO2, the optimum thickness of the CeO2 buffer layer on the IBAD-Gd2Zr2O7 with 18 deg. of Δφ was found to be at least 0.8 μm

  14. Direct patterning of dense cerium oxide thin film by developed ink-jet deposition method at moderate temperatures

    International Nuclear Information System (INIS)

    Direct fabrication of ceria film and patterns were conducted by an ink-jet deposition method where a precursor solution was jetted towards a heated substrate (≤ 300 oC) according to the required pattern without any post heat treatments. X-ray diffraction and Raman spectroscopic analyses revealed that the formed phases were crystallized CeO2 without any impurity phases and consisted of nanosized crystallites of 90%). Scanning electron microscopic analysis revealed that thin film patterns were free of cracks and all the films showed good adherence to the substrate.

  15. Polyimide Aerogel Thin Films

    Science.gov (United States)

    Meador, Mary Ann; Guo, Haiquan

    2012-01-01

    Polyimide aerogels have been crosslinked through multifunctional amines. This invention builds on "Polyimide Aerogels With Three-Dimensional Cross-Linked Structure," and may be considered as a continuation of that invention, which results in a polyimide aerogel with a flexible, formable form. Gels formed from polyamic acid solutions, end-capped with anhydrides, and cross-linked with the multifunctional amines, are chemically imidized and dried using supercritical CO2 extraction to give aerogels having density around 0.1 to 0.3 g/cubic cm. The aerogels are 80 to 95% porous, and have high surface areas (200 to 600 sq m/g) and low thermal conductivity (as low as 14 mW/m-K at room temperature). Notably, the cross-linked polyimide aerogels have higher modulus than polymer-reinforced silica aerogels of similar density, and can be fabricated as both monoliths and thin films.

  16. Polycrystalline thin films

    Science.gov (United States)

    Zweibel, K.; Mitchell, R.; Ullal, H.

    1987-02-01

    This annual report for fiscal year 1986 summarizes the status, accomplishments, and projected future research directions of the Polycrystalline Thin Film Task in the Photovoltaic Program Branch of the Solar Energy Research Institute's Solar Electric Research Division. Subcontracted work in this area has concentrated on the development of CuInSe2 and CdTe technologies. During FY 1986, major progress was achieved by subcontractors in (1) achieving 10.5% (SERI-verified) efficiency with CdTe, (2) improving the efficiency of selenized CuInSe2 solar cells to nearly 8%, and (3) developing a transparent contact to CdTe cells for potential use in the top cells of tandem structures.

  17. Preparation of ZnO:CeO2-x thin films by AP-MOCVD: Structural and optical properties

    International Nuclear Information System (INIS)

    The growth of columnar CeO2, ZnO and ZnO:CeO2-x films on quartz and AA6066 aluminum alloy substrates by economic atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) is reported. A novel and efficient combination of metal acetylacetonate precursors as well as mild operating conditions were used in the deposition process. The correlation among crystallinity, surface morphology and optical properties of the as-prepared films was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM) and UV-vis spectroscopy. The synthesized films showed different crystallographic orientations depending on the ZnO and CeO2 lattice mismatch, cerium content and growth rate. The CeO2 films synthesized in this work showed plate-like compact structures as a result of the growth process typical of CVD. Both pure and ZnO:CeO2-x films were obtained with a hexagonal structure and highly preferred orientation with the c-axis perpendicular to both substrates under the optimal deposition conditions. The microstructure was modified from dense, short round columns to round structures with cavities ('rose-flower-like' structures) and the typical ZnO morphology by controlling the cerium doping the film and substrate nature. High optical transmittance (>87%) was observed in the pure ZnO films. As for the ZnO:CeO2-x films, the optical transmission was decreased and the UV absorption increased, which subsequently was affected by an increase in cerium content. This paper assesses the feasibility of using ZnO:CeO2-x thin films as UV-absorbers in industrial applications. - Graphical abstract: TEM micrographs and their corresponding SAED pattern obtained for the as-deposited ZnO-CeO2-x thin films for a Zn/Ce metallic ratio 16:9.

  18. Thin-film microextraction.

    Science.gov (United States)

    Bruheim, Inge; Liu, Xiaochuan; Pawliszyn, Janusz

    2003-02-15

    The properties of a thin sheet of poly(dimethylsiloxane) (PDMS) membrane as an extraction phase were examined and compared to solid-phase microextraction (SPME) PDMS-coated fiber for application to semivolatile analytes in direct and headspace modes. This new PDMS extraction approach showed much higher extraction rates because of the larger surface area to extraction-phase volume ratio of the thin film. Unlike the coated rod formats of SPME using thick coatings, the high extraction rate of the membrane SPME technique allows larger amounts of analytes to be extracted within a short period of time. Therefore, higher extraction efficiency and sensitivity can be achieved without sacrificing analysis time. In direct membrane SPME extraction, a linear relationship was found between the initial rate of extraction and the surface area of the extraction phase. However, for headspace extraction, the rates were somewhat lower because of the resistance to analyte transport at the sample matrix/headspace barrier. It was found that the effect of this barrier could be reduced by increasing either agitation, temperature, or surface area of the sample matrix/headspace interface. A method for the determination of PAHs in spiked lake water samples was developed based on the membrane PDMS extraction coupled with GC/MS. A linearity of 0.9960 and detection limits in the low-ppt level were found. The reproducibility was found to vary from 2.8% to 10.7%. PMID:12622398

  19. Studies on thin film materials on acrylics for optical applications

    Indian Academy of Sciences (India)

    K Narasimha Rao

    2003-02-01

    Deposition of durable thin film coatings by vacuum evaporation on acrylic substrates for optical applications is a challenging job. Films crack upon deposition due to internal stresses and leads to performance degradation. In this investigation, we report the preparation and characterization of single and multi-layer films of TiO2, CeO2, Substance2 (E Merck, Germany), Al2O3, SiO2 and MgF2 by electron beam evaporation on both glass and PMMA substrates. Optical micrographs taken on single layer films deposited on PMMA substrates did not reveal any cracks. Cracks in films were observed on PMMA substrates when the substrate temperature exceeded 80°C. Antireflection coatings of 3 and 4 layers have been deposited and characterized. Antireflection coatings made on PMMA substrate using Substance2 (H2) and SiO2 combination showed very fine cracks when observed under microscope. Optical performance of the coatings has been explained with the help of optical micrographs.

  20. X-ray photoelectron spectroscopy study of high-k CeO2/La2O3 stacked dielectrics

    International Nuclear Information System (INIS)

    This work presents a detailed study on the chemical composition and bond structures of CeO2/La2O3 stacked gate dielectrics based on x-ray photoelectron spectroscopy (XPS) measurements at different depths. The chemical bonding structures in the interfacial layers were revealed by Gaussian decompositions of Ce 3d, La 3d, Si 2s, and O 1s photoemission spectra at different depths. We found that La atoms can diffuse into the CeO2 layer and a cerium-lanthanum complex oxide was formed in between the CeO2 and La2O3 films. Ce3+ and Ce4+ states always coexist in the as-deposited CeO2 film. Quantitative analyses were also conducted. The amount of CeO2 phase decreases by about 8% as approaching the CeO2/La2O3 interface. In addition, as compared with the single layer La2O3 sample, the CeO2/La2O3 stack exhibits a larger extent of silicon oxidation at the La2O3/Si interface. For the CeO2/La2O3 gate stack, the out-diffused lanthanum atoms can promote the reduction of CeO2 which produce more atomic oxygen. This result confirms the significant improvement of electrical properties of CeO2/La2O3 gated devices as the excess oxygen would help to reduce the oxygen vacancies in the film and would suppress the formation of interfacial La-silicide also

  1. Effect of the laser sputtering parameters on the orientation of a cerium oxide buffer layer on sapphire and the properties of a YBa2Cu3Ox superconducting film

    DEFF Research Database (Denmark)

    Mozhaev, P. B.; Ovsyannikov, G. A.; Skov, Johannes

    1999-01-01

    The effect of the laser sputtering parameters on the crystal properties of CeO2 buffer layers grown on a (1 (1) under bar 02) sapphire substrate and on the properties of superconducting YBa2Cu3Ox thin films are investigated. It is shown that (100) and (111) CeO2 growth is observed, depending on the...

  2. Fabrication of mesoporous cerium dioxide films by cathodic electrodeposition.

    Science.gov (United States)

    Kim, Young-Soo; Lee, Jin-Kyu; Ahn, Jae-Hoon; Park, Eun-Kyung; Kim, Gil-Pyo; Baeck, Sung-Hyeon

    2007-11-01

    Mesoporous cerium dioxide (Ceria, CeO2) thin films have been successfully electrodeposited onto ITO-coated glass substrates from an aqueous solution of cerium nitrate using CTAB (Cetyltrimethylammonium Bromide) as a templating agent. The synthesized films underwent detailed characterizations. The crystallinity of synthesized CeO2 film was confirmed by XRD analysis and HR-TEM analysis, and surface morphology was investigated by SEM analysis. The presence of mesoporosity in fabricated films was confirmed by TEM and small angle X-ray analysis. As-synthesized film was observed from XRD analysis and HR-TEM image to have well-crystallized structure of cubic phase CeO2. Transmission electron microscopy and small angle X-ray analysis revealed the presence of uniform mesoporosity with a well-ordered lamellar phase in the CeO2 films electrodeposited with CTAB templating. PMID:18047150

  3. Thin functional conducting polymer films

    OpenAIRE

    Tian, S.

    2005-01-01

    In the present study, thin functional conducting polyaniline (PANI) films, either doped or undoped, patterned or unpatterned, were prepared by different approaches. The properties of the obtained PANI films were investigated in detail by a combination of electrochemistry with several other techniques, such as SPR, QCM, SPFS, diffraction, etc. The sensing applications (especially biosensing applications) of the prepared PANI films were explored. Firstly, the pure PANI films were prepar...

  4. Interfaces and thin films physics

    International Nuclear Information System (INIS)

    The 1988 progress report of the Interfaces and Thin Film Physics laboratory (Polytechnic School France) is presented. The research program is focused on the thin films and on the interfaces of the amorphous semiconductor materials: silicon and silicon germanium, silicon-carbon and silicon-nitrogen alloys. In particular, the following topics are discussed: the basic processes and the kinetics of the reactive gas deposition, the amorphous materials manufacturing, the physico-chemical characterization of thin films and interfaces and the electron transport in amorphous semiconductors. The construction and optimization of experimental devices, as well as the activities concerning instrumentation, are also described

  5. Electro-deposition of cerium thin film compound, elaboration and characterisation

    International Nuclear Information System (INIS)

    Cerium oxide films are widely studied as a promising alternative to the toxic hexavalent Chromium Cr(VI) based pre-treatments for the corrosion protection of different metals and alloys. Cathodic electro-deposition of Cerium compound thin films was realised on Ti alloy (TA6V) substrates from a Ce(NO3)3, 6H2O in water-ethyl alcohol solutions at 0.01 M. Experimental conditions to obtain homogeneous and crack free thin films were determined. The deposited cerium quantity, as expected, is proportional to the used electric charge, following the Faraday law. Subsequent thermal treatment led to a CeO2 coating, which is expected to increase the TA6V oxidation resistance at high temperatures. The deposits were characterized by Differential Scanning Calorimetry (DSC), optical and scanning electron microscopies.(author)

  6. Thin-film solar cell

    NARCIS (Netherlands)

    Metselaar, J.W.; Kuznetsov, V.I.

    1998-01-01

    The invention relates to a thin-film solar cell provided with at least one p-i-n junction comprising at least one p-i junction which is at an angle alpha with that surface of the thin-film solar cell which collects light during operation and at least one i-n junction which is at an angle beta with t

  7. Controlled growth of epitaxial CeO2 thin films with self-organized nanostructure by chemical solution method

    DEFF Research Database (Denmark)

    Yue, Zhao; Grivel, Jean-Claude

    2013-01-01

    electron microscope observation also reveals that this phenomenon is mainly attributable to the surface re-organization, which is strongly associated with the critical film thickness, crystallization temperature, reducing ability of the crystallization atmosphere as well as the interface properties.......Chemical solution deposition is a versatile technique to grow oxide thin films with self-organized nanostructures. Morphology and crystallographic orientation control of CeO2 thin films grown on technical NiW substrates by a chemical solution deposition method are achieved in this work. Based on an...

  8. Thin-Film Power Transformers

    Science.gov (United States)

    Katti, Romney R.

    1995-01-01

    Transformer core made of thin layers of insulating material interspersed with thin layers of ferromagnetic material. Flux-linking conductors made of thinner nonferromagnetic-conductor/insulator multilayers wrapped around core. Transformers have geometric features finer than those of transformers made in customary way by machining and mechanical pressing. In addition, some thin-film materials exhibit magnetic-flux-carrying capabilities superior to those of customary bulk transformer materials. Suitable for low-cost, high-yield mass production.

  9. Size effects in thin films

    CERN Document Server

    Tellier, CR; Siddall, G

    1982-01-01

    A complete and comprehensive study of transport phenomena in thin continuous metal films, this book reviews work carried out on external-surface and grain-boundary electron scattering and proposes new theoretical equations for transport properties of these films. It presents a complete theoretical view of the field, and considers imperfection and impurity effects.

  10. Nanotemplated lead telluride thin films

    OpenAIRE

    Li, Xiaohong; Nandhakumar, Iris S.; Attard, George S.; Markham, Matthew L.; Smith, David C.; Baumberg, Jeremy J.

    2009-01-01

    Direct lyotropic liquid crystalline templating has been successfully applied to produce nanostructured IV–VI semiconductor PbTe thin films by electrodeposition both on gold and n-type (100) silicon substrates. The PbTe films were characterized by transmission electron microscopy, X-ray diffraction and polarized optical microscopy and the results show that the films have a regular hexagonal nanoarchitecture with a high crystalline rock salt structure and exhibit strong birefringenc...

  11. Thin films and froth flotation

    International Nuclear Information System (INIS)

    The properties of thin, aqueous films on solid surfaces and their central role in the froth flotation process are discussed. The stability of these films can generally be described in terms of electrostatic and van der Waals forces. Significant experimental and theoretical advances are required in many areas (e.g. short range forces, film drainage) before a clear picture of the collision of, adhesion between and detachment of bubbles and particles will emerge. (orig.)

  12. Thin-film ternary superconductors

    International Nuclear Information System (INIS)

    Physical properties and preparation methods of thin film ternary superconductors, (mainly molybdenum chalcogenides) are reviewed. Properties discussed include the superconducting critical fields and critical currents, resistivity and the Hall effect. Experimental results at low temperatures, together with electron microscopy data are used to determine magnetic flux pinning mechanisms in films. Flux pinning results, together with an empirical model for pinning, are used to get estimates for possible applications of thin film ternary superconductors where high current densities are needed in the presence of high magnetic fields. The normal state experimental data is used to derive several Fermi surface parameters, e.g. the Fermi velocity and the effective Fermi surface area. (orig.)

  13. Synergic effect of the TiO2-CeO2 nanoconjugate system on the band-gap for visible light photocatalysis

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Nanostructured TiO2-CeO2 films are successfully synthesized by combining of sputtering and electrophoresis methods. • Synergic effect of CeO2 on TiO2 band gap was demonstrated, CeO2 diminishes it from 3.125 to 2.74. • Morphologic characterization of the nanoconjugate TiO2-CeO2 films by different microscopy techniques. - Abstract: The TiO2-CeO2 photocatalytic system in films is proposed here, in order to obtain photocatalytic systems that can be excited by solar light. The films were obtained through the electrophoretic deposition (EPD) of TiO2-CeO2 gel on sputtered Ti Corning glass substrates. The synergic effect of CeO2 in TiO2 films was analyzed as a function of the optical band gap reduction at different concentrations (1, 5, 10, and 15 mol%). The effect of two thermal treatments was also evaluated. The lowest band gap value was obtained for the sample with 5 mol% ceria that was thermally treated at 700 °C. The nanostructured films were characterized by Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high angle annular dark field (HAADF), high resolution transmission electron microscopy (HRTEM), and atomic force microscopy (AFM). The nanocomposites were formed by TiO2 and CeO2 nanoparticles in the anatase and fluorite type phases, respectively

  14. Calorimetry of epitaxial thin films.

    Science.gov (United States)

    Cooke, David W; Hellman, F; Groves, J R; Clemens, B M; Moyerman, S; Fullerton, E E

    2011-02-01

    Thin film growth allows for the manipulation of material on the nanoscale, making possible the creation of metastable phases not seen in the bulk. Heat capacity provides a direct way of measuring thermodynamic properties of these new materials, but traditional bulk calorimetric techniques are inappropriate for such a small amount of material. Microcalorimetry and nanocalorimetry techniques exist for the measurements of thin films but rely on an amorphous membrane platform, limiting the types of films which can be measured. In the current work, ion-beam-assisted deposition is used to provide a biaxially oriented MgO template on a suspended membrane microcalorimeter in order to measure the specific heat of epitaxial thin films. Synchrotron x-ray diffraction showed the biaxial order of the MgO template. X-ray diffraction was also used to prove the high quality of epitaxy of a film grown onto this MgO template. The contribution of the MgO layer to the total heat capacity was measured to be just 6.5% of the total addenda contribution. The heat capacity of a Fe(.49)Rh(.51) film grown epitaxially onto the device was measured, comparing favorably to literature data on bulk crystals. This shows the viability of the MgO∕SiN(x)-membrane-based microcalorimeter as a way of measuring the thermodynamic properties of epitaxial thin films. PMID:21361612

  15. Oxygen level: the dominant of resistive switching characteristics in cerium oxide thin films

    International Nuclear Information System (INIS)

    Currently, resistive switching mechanisms in metal oxide thin films are not clearly understood due to lack of solid evidence. In this work, the switching behaviour of the Au/CeO2/conductive glass structure was analysed, where reproducible and pronounced resistive switching characteristics were obtained. The role of oxygen vacancies in switching characteristics was investigated. The concentration of oxygen vacancies in the CeO2 thin films was controlled by post-annealing and monitored by x-ray photon spectroscopy. The reduction in the switching ratio and the intensity of the peak associated with oxygen concentration O 1s level after annealing treatment confirmed the dominating role of oxygen vacancies in switching behaviour.

  16. Synthesis and electrochemical properties of CeO2 nanoparticle modified TiO2 nanotube arrays

    International Nuclear Information System (INIS)

    In this paper, a cerium dioxide (CeO2) modified titanium dioxide (TiO2) nanotube array film was fabricated by electrodeposition of CeO2 nanoparticles onto an anodized TiO2 nanotube array. The structural investigation by X-ray diffraction, scanning electron microscopy and transmission electron microscopy indicated that the CeO2 nanoparticles grew uniformly on the walls of the TiO2 nanotubes. The composite was composed of cubic-phase CeO2 crystallites and anatase-phase TiO2 after annealing at 450 oC. The cyclic voltammetry and chronoamperometric charge/discharge measurement results indicated that the CeO2 modification obviously increased the charge storage capacity of the TiO2 nanotubes. The charge transfer process at the surface, that is, the pseudocapacitance, was the dominate mechanism of the charge storage in CeO2-modified TiO2 nanotubes. The greater number of surface active sites resulting from uniform application of the CeO2 nanoparticles to the well-aligned TiO2 nanotubes contributed to the enhancement of the charge storage density.

  17. Semiconductor-nanocrystal/conjugated polymer thin films

    Science.gov (United States)

    Alivisatos, A. Paul; Dittmer, Janke J.; Huynh, Wendy U.; Milliron, Delia

    2010-08-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  18. Chemical approach to the deposition of textured CeO2 buffer layers based on sol gel dip coating

    International Nuclear Information System (INIS)

    The widespread use of vacuum techniques for the development of coated conductors, in which buffer and superconducting (REBa2Cu3O7-δ) layers are deposited epitaxially on a substrate, is well established in the research environment. However, obtaining uninterrupted deposition at high speed, increasing flexibility in composition and in film thickness and attaining independence of geometric constraints are areas in which many vacuum techniques will need sustained development in order to answer industrial demands. This work describes the deposition of textured CeO2 buffer layers based on sol gel dip coating under atmospheric environment and from aqueous precursor materials. Research has been performed towards the deposition of CeO2-buffer layers using the amorphous citrate method on sapphire substrates and Ni-W foils. Coating is performed using the dip-coating technique, which allows extension to a continuous system. The withdrawal speed and the thermal treatment have been optimised in order to obtain highly oriented (001) layers exhibiting a smooth and crack-free morphology both on ceramic and metallic substrates. From the results it was concluded that sintering atmosphere and sintering temperature play a crucial role in the growth mechanism. This study describes the structural and morphological analysis of the thin layer with special attention to the difference between ceramic and metallic substrates. (orig.)

  19. Preparation of thin vyns films

    International Nuclear Information System (INIS)

    The fabrication of thin films of VYNS resin (copolymer of chloride and vinyl acetate) of superficial density from 3 to 50 μg/cm2 with solutions in cyclohexanone is presented. Study and discussion of some properties compared with formvar film (polyvinyl formals). It appears that both can be used as source supports but formvar films are prepared more easily and more quickly, in addition they withstand higher temperatures. The main quality of VYNS is that they can be easily separated even several days after their preparation

  20. Shielding superconductors with thin films

    CERN Document Server

    Posen, Sam; Catelani, Gianluigi; Liepe, Matthias U; Sethna, James P

    2015-01-01

    Determining the optimal arrangement of superconducting layers to withstand large amplitude AC magnetic fields is important for certain applications such as superconducting radiofrequency cavities. In this paper, we evaluate the shielding potential of the superconducting film/insulating film/superconductor (SIS') structure, a configuration that could provide benefits in screening large AC magnetic fields. After establishing that for high frequency magnetic fields, flux penetration must be avoided, the superheating field of the structure is calculated in the London limit both numerically and, for thin films, analytically. For intermediate film thicknesses and realistic material parameters we also solve numerically the Ginzburg-Landau equations. It is shown that a small enhancement of the superheating field is possible, on the order of a few percent, for the SIS' structure relative to a bulk superconductor of the film material, if the materials and thicknesses are chosen appropriately.

  1. Thin Film Solid Lubricant Development

    Science.gov (United States)

    Benoy, Patricia A.

    1997-01-01

    Tribological coatings for high temperature sliding applications are addressed. A sputter-deposited bilayer coating of gold and chromium is investigated as a potential solid lubricant for protection of alumina substrates during sliding at high temperature. Evaluation of the tribological properties of alumina pins sliding against thin sputtered gold films on alumina substrates is presented.

  2. Thin film polymeric gel electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Derzon, Dora K. (1554 Rosalba St. NE., Albuquerque, Bernalillo County, NM 87112); Arnold, Jr., Charles (3436 Tahoe, NE., Albuquerque, Bernalillo County, NM 87111); Delnick, Frank M. (9700 Fleming Rd., Dexter, MI 48130)

    1996-01-01

    Novel hybrid thin film electrolyte, based on an organonitrile solvent system, which are compositionally stable, environmentally safe, can be produced efficiently in large quantity and which, because of their high conductivities .apprxeq.10.sup.-3 .OMEGA..sup.-1 cm.sup.-1 are useful as electrolytes for rechargeable lithium batteries.

  3. Optical thin films test methodology

    International Nuclear Information System (INIS)

    An over view of different test procedures for thin film optical coatings have been discussed in this paper. These procedures cover optical coatings for high precision and commercial applications. These tests include visual inspection test, self adhesion test, moderate abrasion test, etc. Two groups of testing sequences have been given depending upon the environmental conditions. (author)

  4. Thermal stability of NdBCO/YBCO/MgO thin film seeds

    Science.gov (United States)

    Volochová, D.; Kavečanský, V.; Antal, V.; Diko, P.; Yao, X.

    2016-04-01

    Thermal stability of the Nd1+x Ba2-x Cu3O7-δ (Nd-123 or NdBCO) thin films deposited on MgO substrate, with YBa2Cu3O7-δ (Y-123 or YBCO) buffer layer (NdBCO/YBCO/MgO thin film), has been experimentally studied in order to determine the optimal film thickness acting as seed for bulk YBCO growth. YBCO bulk superconductors with Y2BaCuO5 (Y-211) and CeO2 addition were prepared by the top seeded melt growth process in a chamber furnace using NdBCO/YBCO/MgO thin film seeds of different thicknesses (200-700 nm with 20 nm YBCO buffer layer) and different maximum temperatures, T max. The maximum temperatures varied in the range of 1040 °C-1125 °C. The highest thermal stability 1118 °C was observed in the case of NdBCO/YBCO/MgO thin film of 300 nm thickness. These results are corroborated with differential scanning calorimetry and high temperature x-ray diffraction measurements, as well as microstructure observations.

  5. Facile hydrothermal synthesis of CeO2 nanopebbles

    Indian Academy of Sciences (India)

    N Sabari Arul; D Mangalaraj; Jeong In Han

    2015-09-01

    Cerium oxide (CeO2) nanopebbles have been synthesized using a facile hydrothermal method. X-ray diffraction pattern (XRD) and transmission electron microscopy analyses confirm the presence of CeO2 nanopebbles. XRD shows the formation of cubic fluorite CeO2 and the average particle size estimated from the Scherrer formula was found to be 6.69 nm. X-ray absorption spectrum of CeO2 nanopebbles exhibits two main sharp white lines at 880 and 898 eV due to the spin orbital splitting of 4 and 5. Optical absorption for the synthesized CeO2 nanopebbles exhibited a blue shift (g = 3.35 eV) with respect to the bulk CeO2 (g = 3.19 eV), indicating the existence of quantum confinement effects.

  6. Superfast Thinning of a Nanoscale Thin Liquid Film

    OpenAIRE

    Winkler, Michael; Kofod, Guggi; Krastev, Rumen; Abel, Markus

    2011-01-01

    This fluid dynamics video demonstrates an experiment on superfast thinning of a freestanding thin aqueous film. The production of such films is of fundamental interest for interfacial sciences and the applications in nanoscience. The stable phase of the film is of the order $5-50\\,nm$; nevertheless thermal convection can be established which changes qualitatively the thinning behavior from linear to exponentially fast. The film is thermally driven on one spot by a very cold needle, establishi...

  7. Phase Coarsening in Thin Films

    Science.gov (United States)

    Wang, K. G.; Glicksman, M. E.

    2015-08-01

    Phase coarsening (Ostwald ripening) phenomena are ubiquitous in materials growth processes such as thin film formation. The classical theory explaining late-stage phase coarsening phenomena was developed by Lifshitz and Slyozov, and by Wagner in the 1960s. Their theory is valid only for a vanishing volume fraction of the second phase in three dimensions. However, phase coarsening in two-dimensional systems is qualitatively different from that in three dimensions. In this paper, the many-body concept of screening length is reviewed, from which we derive the growth law for a `screened' phase island, and develop diffusion screening theory for phase coarsening in thin films. The coarsening rate constant, maximum size of phase islands in films, and their size distribution function will be derived from diffusion screening theory. A critical comparison will be provided of prior coarsening concepts and improvements derived from screening approaches.

  8. Probing the bulk ionic conductivity by thin film hetero-epitaxial engineering

    KAUST Repository

    Pergolesi, Daniele

    2015-02-01

    Highly textured thin films with small grain boundary regions can be used as model systems to directly measure the bulk conductivity of oxygen ion conducting oxides. Ionic conducting thin films and epitaxial heterostructures are also widely used to probe the effect of strain on the oxygen ion migration in oxide materials. For the purpose of these investigations a good lattice matching between the film and the substrate is required to promote the ordered film growth. Moreover, the substrate should be a good electrical insulator at high temperature to allow a reliable electrical characterization of the deposited film. Here we report the fabrication of an epitaxial heterostructure made with a double buffer layer of BaZrO3 and SrTiO3 grown on MgO substrates that fulfills both requirements. Based on such template platform, highly ordered (001) epitaxially oriented thin films of 15% Sm-doped CeO2 and 8 mol% Y2O3 stabilized ZrO2 are grown. Bulk conductivities as well as activation energies are measured for both materials, confirming the success of the approach. The reported insulating template platform promises potential application also for the electrical characterization of other novel electrolyte materials that still need a thorough understanding of their ionic conductivity.

  9. Probing the bulk ionic conductivity by thin film hetero-epitaxial engineering

    International Nuclear Information System (INIS)

    Highly textured thin films with small grain boundary regions can be used as model systems to directly measure the bulk conductivity of oxygen ion conducting oxides. Ionic conducting thin films and epitaxial heterostructures are also widely used to probe the effect of strain on the oxygen ion migration in oxide materials. For the purpose of these investigations a good lattice matching between the film and the substrate is required to promote the ordered film growth. Moreover, the substrate should be a good electrical insulator at high temperature to allow a reliable electrical characterization of the deposited film. Here we report the fabrication of an epitaxial heterostructure made with a double buffer layer of BaZrO3 and SrTiO3 grown on MgO substrates that fulfills both requirements. Based on such template platform, highly ordered (001) epitaxially oriented thin films of 15% Sm-doped CeO2 and 8 mol% Y2O3 stabilized ZrO2 are grown. Bulk conductivities as well as activation energies are measured for both materials, confirming the success of the approach. The reported insulating template platform promises potential application also for the electrical characterization of other novel electrolyte materials that still need a thorough understanding of their ionic conductivity. (paper)

  10. Thin films stress modeling : a novel approach

    OpenAIRE

    Bhattacharyya, A. S.; Ramgiri, Praveen Kumar

    2015-01-01

    A novel approach to estimate the thin film stress was discussed based on surface tension. The effect of temperature and film thickness was studies. The effect of stress on the film mechanical properties was observed.

  11. Convenient synthesis of CeO2 nanotubes

    International Nuclear Information System (INIS)

    A simple and facile route was used in the fabrication of CeO2 nanotubes within anodic alumina membrane. A piece of membrane was first immersed into Ce(NO3)3 aqueous solution under ambient conditions. After dried at 50 deg. C and thermally calcined at 150 deg. C and 550 deg. C, CeO2 nanotubes can be easily synthesized. The characterization with electron microscopy and X-ray diffraction indicated that CeO2 nanotubes were composed of tiny well-crystalline CeO2 nanoparticles

  12. Lipase immobilized on nanostructured cerium oxide thin film coated on transparent conducting oxide electrode for butyrin sensing

    International Nuclear Information System (INIS)

    Nanostructured cerium oxide (CeO2) thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique with cerium nitrate salt, Ce(NO3)3·6H2O as precursor. Fluorine doped cadmium oxide (CdO:F) thin film prepared using spray pyrolysis technique acts as the TCO film and hence the bare electrode. The structural, morphological and elemental characterizations of the films were carried out using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray analysis (EDX) respectively. The diffraction peak positions in XRD confirmed the formation of highly crystalline ceria with cubic structure and FE-SEM images showed uniform adherent films with granular morphology. The band gaps of CeO2 and TCO were found to be 3.2 eV and 2.6 eV respectively. Lipase enzyme was physisorbed on the surface of CeO2/TCO film to form the lipase/nano-CeO2/TCO bioelectrode. Sensing studies were carried out using cyclic voltammetry and amperometry, with lipase/nano-CeO2/TCO as working electrode and tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33–1.98 mM) with a lowest detection limit of 2 μM with sharp response time of 5 s and a shelf life of about 6 weeks. -- Graphical abstract: Nanostructured cerium oxide thin films were deposited on transparent conducting oxide (TCO) substrate using spray pyrolysis technique. Fluorine doped cadmium oxide (CdO:F) thin film acts as the TCO film and hence the working electrode. Lipase enzyme was physisorbed on the surface of CeO2/TCO film and hence the lipase/nano-CeO2/TCO bioelectrode has been fabricated. Sensing studies were carried out using cyclic voltammetry and amperometry with tributyrin as substrate. The mediator-free biosensor with nanointerface exhibited excellent linearity (0.33–1.98 mM) with a lowest detection limit of 2 μM with sharp response time of 5 s and a shelf life of about 6 weeks. Highlights:

  13. Selective inorganic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, M.L.F.; Pohl, P.I.; Brinker, C.J. [Sandia National Labs., Albuquerque, NM (United States)

    1997-04-01

    Separating light gases using membranes is a technology area for which there exists opportunities for significant energy savings. Examples of industrial needs for gas separation include hydrogen recovery, natural gas purification, and dehydration. A membrane capable of separating H{sub 2} from other gases at high temperatures could recover hydrogen from refinery waste streams, and facilitate catalytic dehydrogenation and the water gas shift (CO + H{sub 2}O {yields} H{sub 2} + CO{sub 2}) reaction. Natural gas purification requires separating CH{sub 4} from mixtures with CO{sub 2}, H{sub 2}S, H{sub 2}O, and higher alkanes. A dehydrating membrane would remove water vapor from gas streams in which water is a byproduct or a contaminant, such as refrigeration systems. Molecular sieve films offer the possibility of performing separations involving hydrogen, natural gas constituents, and water vapor at elevated temperatures with very high separation factors. It is in applications such as these that the authors expect inorganic molecular sieve membranes to compete most effectively with current gas separation technologies. Cryogenic separations are very energy intensive. Polymer membranes do not have the thermal stability appropriate for high temperature hydrogen recovery, and tend to swell in the presence of hydrocarbon natural gas constituents. The authors goal is to develop a family of microporous oxide films that offer permeability and selectivity exceeding those of polymer membranes, allowing gas membranes to compete with cryogenic and adsorption technologies for large-scale gas separation applications.

  14. Heteroepitaxy of Cerium Oxide Thin Films on Cu(111

    Directory of Open Access Journals (Sweden)

    Josef Mysliveček

    2015-09-01

    Full Text Available An important part of fundamental research in catalysis is based on theoretical and modeling foundations which are closely connected with studies of single-crystalline catalyst surfaces. These so-called model catalysts are often prepared in the form of epitaxial thin films, and characterized using advanced material characterization techniques. This concept provides the fundamental understanding and the knowledge base needed to tailor the design of new heterogeneous catalysts with improved catalytic properties. The present contribution is devoted to development of a model catalyst system of CeO2 (ceria on the Cu(111 substrate. We propose ways to experimentally characterize and control important parameters of the model catalyst—the coverage of the ceria layer, the influence of the Cu substrate, and the density of surface defects on ceria, particularly the density of step edges and the density and the ordering of the oxygen vacancies. The large spectrum of controlled parameters makes ceria on Cu(111 an interesting alternative to a more common model system ceria on Ru(0001 that has served numerous catalysis studies, mainly as a support for metal clusters.

  15. Pulsed laser deposition of thin YBCO films on faceted YSZ single crystal fibers

    International Nuclear Information System (INIS)

    Flexible rods of single crystals of 9% Y2O3-stabilized ZrO2 (YSZ) were used as substrates for deposition of high-critical temperature superconducting (HTS) thin films. YSZ fibers were prepared by mini-pedestal method with laser heating and had average diameter of 300 micrometers and 30 mm length. X-ray diffraction analysis demonstrated high crystalline quality of obtained fibers and also indicated the presence of 15° deviation of the fiber axis from the [001] YSZ direction. Thin YBa2Cu3O7−x films were grown by pulsed laser deposition on YSZ rods using CeO2 buffer layer. Films have shown high critical temperature of 90 K with sharp superconducting transition. Critical current density was estimated to about 3×104 A/cm2 at 80 K. Temperature dependence of critical current density suggests granular structure of films with grain size about several microns. Our results demonstrate feasibility of flexible YSZ fibers coated by HTS thin films for practical use.

  16. Thin films of soft matter

    CERN Document Server

    Kalliadasis, Serafim

    2007-01-01

    A detailed overview and comprehensive analysis of the main theoretical and experimental advances on free surface thin film and jet flows of soft matter is given. At the theoretical front the book outlines the basic equations and boundary conditions and the derivation of low-dimensional models for the evolution of the free surface. Such models include long-wave expansions and equations of the boundary layer type and are analyzed via linear stability analysis, weakly nonlinear theories and strongly nonlinear analysis including construction of stationary periodic and solitary wave and similarity solutions. At the experimental front a variety of very recent experimental developments is outlined and the link between theory and experiments is illustrated. Such experiments include spreading drops and bubbles, imbibitions, singularity formation at interfaces and experimental characterization of thin films using atomic force microscopy, ellipsometry and contact angle measurements and analysis of patterns using Minkows...

  17. Polycrystalline thin films : A review

    Energy Technology Data Exchange (ETDEWEB)

    Valvoda, V. [Charles Univ., Prague (Czech Republic). Faculty of Mathematics and Physics

    1996-09-01

    Polycrystalline thin films can be described in terms of grain morphology and in terms of their packing by the Thornton`s zone model as a function of temperature of deposition and as a function of energy of deposited atoms. Grain size and preferred grain orientation (texture) can be determined by X-ray diffraction (XRD) methods. A review of XRD analytical methods of texture analysis is given with main attention paid to simple empirical functions used for texture description and for structure analysis by joint texture refinement. To illustrate the methods of detailed structure analysis of thin polycrystalline films, examples of multilayers are used with the aim to show experiments and data evaluation to determine layer thickness, periodicity, interface roughness, lattice spacing, strain and the size of diffraction coherent volumes. The methods of low angle and high angle XRD are described and discussed with respect to their complementary information content.

  18. Organic thin-film photovoltaics

    OpenAIRE

    Liu, Miaoyin

    2010-01-01

    Zusammenfassung Zur Verbesserung der Leistungsumwandlung in organischen Solarzellen sind neue Materialien von zentraler Bedeutung, die sämtliche Erfordernisse für organische Photovoltaik-Elemente erfüllen. In der vorliegenden Arbeit „Organic thin-film photovoltaics“ wurden im Hinblick auf ein besseres Verständnis der Zusammenhänge zwischen molekularer Struktur und der Leistungsfähigkeit neue Materialien in „bulk-heterojunction“ Solarzellen und in Festphasen-Farbstoffsensibilisierten ...

  19. Photoconductivity of thin organic films

    International Nuclear Information System (INIS)

    Thin organic films were deposited on silicon oxide surfaces with golden interdigitated electrodes (interelectrode gap was 2 μm), and the film resistivities were measured in dark and under white light illumination. The compounds selected for the measurements include molecules widely used in solar cell applications, such as polythiophene (PHT), fullerene (C60), pyrelene tetracarboxylic diimide (PTCDI) and copper phthalocyanine (CuPc), as well as molecules potentially interesting for photovoltaic applications, e.g. porphyrin-fullerene dyads. The films were deposited using thermal evaporation (e.g. for C60 and CuPc films), spin coating for PHT, and Langmuir-Schaeffer for the layer-by-layer deposition of porphyrin-fullerene dyads. The most conducting materials in the series are films of PHT and CuPc with resistivities 1.2 x 103 Ω m and 3 x 104 Ω m, respectively. Under light illumination resistivity of all films decreases, with the strongest light effect observed for PTCDI, for which resistivity decreases by 100 times, from 3.2 x 108 Ω m in dark to 3.1 x 106 Ω m under the light.

  20. Zinc oxide thin film acoustic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah [Department of Physics , College of Science, Al-Mustansiriyah University, Baghdad (Iraq); Mansour, Hazim Louis [Department of Physics , College of Education, Al-Mustansiriyah University, Baghdad (Iraq)

    2013-12-16

    This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

  1. Flexible Tactile Sensor Using Polyurethane Thin Film

    OpenAIRE

    Seiji Aoyagi; Tomokazu Takahashi; Masato Suzuki

    2012-01-01

    A novel capacitive tactile sensor using a polyurethane thin film is proposed in this paper. In previous studies, capacitive tactile sensors generally had an air gap between two electrodes in order to enhance the sensitivity. In this study, there is only polyurethane thin film and no air gap between the electrodes. The sensitivity of this sensor is higher than the previous capacitive tactile sensors because the polyurethane is a fairly flexible elastomer and the film is very thin (about 1 µm)....

  2. Silicon Thin-Film Solar Cells

    OpenAIRE

    2007-01-01

    We review the field of thin-film silicon solar cells with an active layer thickness of a few micrometers. These technologies can potentially lead to low cost through lower material costs than conventional modules, but do not suffer from some critical drawbacks of other thin-film technologies, such as limited supply of basic materials or toxicity of the components. Amorphous Si technology is the oldest and best established thin-film silicon technology. Amorphous silicon is deposited at low t...

  3. Thin films for emerging applications v.16

    CERN Document Server

    Francombe, Maurice H

    1992-01-01

    Following in the long-standing tradition of excellence established by this serial, this volume provides a focused look at contemporary applications. High Tc superconducting thin films are discussed in terms of ion beam and sputtering deposition, vacuum evaporation, laser ablation, MOCVD, and other deposition processes in addition to their ultimate applications. Detailed treatment is also given to permanent magnet thin films, lateral diffusion and electromigration in metallic thin films, and fracture and cracking phenomena in thin films adhering to high-elongation substrates.

  4. Minerals deposited as thin films

    International Nuclear Information System (INIS)

    Free matrix effects are due to thin film deposits. Thus, it was decided to investigate this technique as a possibility to use pure oxide of the desired element, extrapolating its concentration from analytical curves made with avoiding, at the same time, mathematical corrections. The proposed method was employed to determine iron and titanium concentrations in geological samples. The range studied was 0.1-5%m/m for titanium and 5-20%m/m for iron. For both elements the reproducibility was about 7% and differences between this method and other chemical determinations were 15% for titanium and 7% for iron. (Author)

  5. Interactions in thin aqueous films

    OpenAIRE

    Hänni-Ciunel, Katarzyna

    2006-01-01

    In der Arbeit werden die Wechselwirkungen in dünnen flüssigen Filmen untersucht und modifiziert. Schaum- (gas/flüssig/gas) und Benetzungsfilme (gas/flüssig/fest) werden mittels Thin Film Pressure Balance (TFPB) untersucht. Die Apparatur wurde im Rahmen der Arbeit für die Studien an asymmetrischen Filmen aufgebaut und modifiziert. Die Ladungen an den Filmgrenzflächen werden gezielt modifiziert. Die Adsoprtion von Tensiden bestimmt die Oberflächenladung an der gas/flüssig Grenzfläche. Die Oberf...

  6. The role of thin films in wetting

    OpenAIRE

    Marmur, Abraham

    1988-01-01

    The role of thin films in wetting is reviewed. Three modes of spontaneous spreading are discussed : incomplete spreading, complete spreading and mixed-mode spreading. A thin film can be either molecular or colloidal in thickness. Molecularly adsorbed films are mainly associated with incomplete spreading. Colloidal films usually extend from the bulk of the liquid in dynamic situations of complete spreading. Their existence at equilibriuim with the bulk depends on the orientation in the gravita...

  7. Microstructural evolution of tungsten oxide thin films

    International Nuclear Information System (INIS)

    Tungsten oxide thin films are of great interest due to their promising applications in various optoelectronic thin film devices. We have investigated the microstructural evolution of tungsten oxide thin films grown by DC magnetron sputtering on silicon substrate. The structural characterization and surface morphology were carried out using X-ray diffraction and Scanning Electron Microscopy (SEM). The as deposited films were amorphous, where as, the films annealed above 400 deg. were crystalline. In order to explain the microstructural changes due to annealing, we have proposed a 'instability wheel' model for the evolution of the microstructure. This model explains the transformation of mater into various geometries within them selves, followed by external perturbation.

  8. Template electrosynthesis of CeO2 nanotubes

    International Nuclear Information System (INIS)

    Nanotube arrays of CeO2 were produced in a single step by potentiostatic electrochemical deposition from a non-aqueous electrolyte, using anodic alumina membrane templates. The CeO2 nanotubes showed a polycrystalline structure, and they were assembled in the membrane nanochannels. The nanotubes had somewhat uniform diameters, with an average external value of about 210 nm, and a maximum length of about 60 μm; the latter parameter was controlled by the electrodeposition time. Each single nanotube was found to consist of crystalline grains having a size of about 3 nm. Raman analysis shows that these CeO2 nanotubes are suitable for catalytic applications

  9. Thin liquid films dewetting and polymer flow

    CERN Document Server

    Blossey, Ralf

    2012-01-01

    This book is a treatise on the thermodynamic and dynamic properties of thin liquid films at solid surfaces and, in particular, their rupture instabilities. For the quantitative study of these phenomena, polymer thin films haven proven to be an invaluable experimental model system.   What is it that makes thin film instabilities special and interesting, warranting a whole book? There are several answers to this. Firstly, thin polymeric films have an important range of applications, and with the increase in the number of technologies available to produce and to study them, this range is likely to expand. An understanding of their instabilities is therefore of practical relevance for the design of such films.   Secondly, thin liquid films are an interdisciplinary research topic. Interdisciplinary research is surely not an end to itself, but in this case it leads to a fairly heterogeneous community of theoretical and experimental physicists, engineers, physical chemists, mathematicians and others working on the...

  10. Ellipsometric Studies on Silver Telluride Thin Films

    Directory of Open Access Journals (Sweden)

    M. Pandiaraman

    2011-01-01

    Full Text Available Silver telluride thin films of thickness between 45 nm and 145 nm were thermally evaporated on well cleaned glass substrates at high vacuum better than 10 – 5 mbar. Silver telluride thin films are polycrystalline with monoclinic structure was confirmed by X-ray diffractogram studies. AFM and SEM images of these films are also recorded. The phase ratio and amplitude ratio of these films were recorded in the wavelength range between 300 nm and 700 nm using spectroscopic ellipsometry and analysed to determine its optical band gap, refractive index, extinction coefficient, and dielectric functions. High absorption coefficient determined from the analysis of recorded spectra indicates the presence of direct band transition. The optical band gap of silver telluride thin films is thickness dependent and proportional to square of reciprocal of thickness. The dependence of optical band gap of silver telluride thin films on film thickness has been explained through quantum size effect.

  11. Fabrication and evaluation of green-light emitting Ta2O5:Er, Ce co-sputtered thin films

    OpenAIRE

    Miura, K; Osawa, T; Suzuki, T.; Y. Yokota; O. Hanaizumi

    2015-01-01

    Erbium and cerium co-doped tantalum-oxide (Ta2O5:Er, Ce) thin films were fabricated using radio-frequency co-sputtering of Ta2O5, Er2O3, and CeO2 for the first time. Enhanced green-light emission due to Er3+ that seems to be sensitized by Ce3+ was observed from the film annealed at 900 °C for 20 min. From XRD measurements of the films, the β-Ta2O5 (orthorhombic), δ-Ta2O5 (hexagonal), and (201) Ta2O5 phases seem to be very important for obtaining green PL from them. Such Ta2O5:Er, Ce co-sputte...

  12. Structural and morphological evolution of cerium oxide thin film on silicon prepared by metal-organic decomposition route

    International Nuclear Information System (INIS)

    Thin film of cerium oxide (CeO2) were prepared on silicon (Si) substrate by metal organic decomposition route. 0.25 M of cerium (III) acetylacetonate (acac) was used as starting materials with the addition of methanol and acetic acid as solvents. Oxide conversion of the film by thermal treatment was conducted at temperature ranging from 400 degree Celsius to 1000 degree Celsius for 15 min in argon ambient. X-ray diffraction (XRD) analysis utilizing Cukα radiation (Model Brukker DiffracPlus), Filmetrics system measurement, field emission scanning electron microscope (FESEM) (Model Zeiss Supra 35 VP FESEM) and atomic force microscopy (AFM) (Model SII Nanonavi) were employed to characterize the phase formed and morphologies of the film produced. (author)

  13. Three-Dimensional Structure of CeO2 Nanocrystals

    DEFF Research Database (Denmark)

    Tan, Joyce Pei Ying; Tan, Hui Ru; Boothroyd, Chris;

    2011-01-01

    Visualization of three-dimensional (3D) structures of materials at the nanometer scale can shed important information on the performance of their applications and provide insight into the growth mechanism of shape-controlled nanomaterials. In this paper, the 3D structures and growth pathway of CeO2...... samples synthesized under different conditions. The homogeneous growth environment in solution with polyvinylpyrrolidone (PVP) molecules led to the formation of regular octahedral CeO2 nanocrystals with small {001} facet truncations. When the PVP surfactant was removed, the aggregation of regular...... truncated octahedral CeO2 particles through a lattice matched interface generated irregular compressed truncated octahedral CeO2 nanoparticles. The formation of this irregular shape is attributed to the lower surface diffusion and slow incorporation of atoms on surfaces by step attachment of the fused...

  14. Electrostatic thin film chemical and biological sensor

    Science.gov (United States)

    Prelas, Mark A.; Ghosh, Tushar K.; Tompson, Jr., Robert V.; Viswanath, Dabir; Loyalka, Sudarshan K.

    2010-01-19

    A chemical and biological agent sensor includes an electrostatic thin film supported by a substrate. The film includes an electrostatic charged surface to attract predetermined biological and chemical agents of interest. A charge collector associated with said electrostatic thin film collects charge associated with surface defects in the electrostatic film induced by the predetermined biological and chemical agents of interest. A preferred sensing system includes a charge based deep level transient spectroscopy system to read out charges from the film and match responses to data sets regarding the agents of interest. A method for sensing biological and chemical agents includes providing a thin sensing film having a predetermined electrostatic charge. The film is exposed to an environment suspected of containing the biological and chemical agents. Quantum surface effects on the film are measured. Biological and/or chemical agents can be detected, identified and quantified based on the measured quantum surface effects.

  15. Direct liquid injection chemical vapor deposition of platinum doped cerium oxide thin films

    International Nuclear Information System (INIS)

    Thin films of Pt-doped CeO2 were grown by direct liquid injection chemical vapor deposition on silicon wafer covered by native oxide at 400 °C using Ce(IV) alkoxide and organoplatinum(IV) as precursors. X-ray photoelectron spectra evidenced that the platinum oxidation state is linked to the deposition way. For platinum deposited on top of cerium oxide thin films previously grown, metallic platinum particles were obtained. Cerium and platinum codeposition allowed obtaining a Pt0 and Pt2+ mixture with the Pt2+ to Pt ratio strongly dependent on the platinum flow rate during the deposition. Indeed, the lower the platinum precursor flow rate is, the higher the Pt2+ to Pt ratio is. Moreover, surface and cross-sectional morphologies obtained by scanning electron microscopy evidenced porous layers in any case. - Highlights: • Pt-doped ceria were synthesized. • Films were obtained by direct liquid injection chemical vapor deposition. • Simultaneous deposition of Pt and Ce was used to obtain homogeneous films. • Pt2+ was revealed through X-ray photoelectron spectroscopy. • Different routes were used to exalt Pt2+/Pt ratio

  16. Influence of the Ion-to-Atom Ratio on the Structure of CeO2 Buffer Layer by Ion Beam Assisted E-Beam Evaporation

    Science.gov (United States)

    Kim, Chang Su; Jo, Sung Jin; Kim, Woo Jin; Koo, Won Hoe; Baik, Hong Koo; Lee, Se Jong

    2005-09-01

    Using ion-beam assisted e-beam evaporation with the ion beam directed at 55° to the normal of the film plane, (200) oriented CeO2 films with biaxial texture were deposited on Hastelloy C276 substrates at room temperature. The crystalline quality and in-plane orientation of films was investigated by X-ray diffraction 2θ-scan and Φ-scan, atomic force microscopy (AFM). It was shown that the in-plane and out-of-plane textures of the CeO2 films were controlled by the deposition parameters. The orientation of the films was studied as a function of ion-to-atom ratio and film thickness. The ion-to-atom ratio was varied by independently adjusting the deposition rate and the ion current density. Under optimum condition, (200) textured CeO2 films have been successfully grown on Hastelloy C276.

  17. Nanostructured thin films and coatings functional properties

    CERN Document Server

    Zhang, Sam

    2010-01-01

    The second volume in ""The Handbook of Nanostructured Thin Films and Coatings"" set, this book focuses on functional properties, including optical, electronic, and electrical properties, as well as related devices and applications. It explores the large-scale fabrication of functional thin films with nanoarchitecture via chemical routes, the fabrication and characterization of SiC nanostructured/nanocomposite films, and low-dimensional nanocomposite fabrication and applications. The book also presents the properties of sol-gel-derived nanostructured thin films as well as silicon nanocrystals e

  18. PREPARATION AND CHARACTERIZATION OF POLY-CRYSTALLINE SILICON THIN FILM

    Institute of Scientific and Technical Information of China (English)

    Y.F. Hu; H. Shen; Z.Y. Liu; L.S. Wen

    2003-01-01

    Poly-crystalline silicon thin film has big potential of reducing the cost of solar cells.In this paper the preparation of thin film is introduced, and then the morphology of poly-crystalline thin film is discussed. On the film we developed poly-crystalline silicon thin film solar cells with efficiency up to 6. 05% without anti-reflection coating.

  19. Electrochemical properties of Atomic layer deposition processed CeO2 as a protective layer for the molten carbonate fuel cell cathode

    International Nuclear Information System (INIS)

    Highlights: • Nano-structured CeO2-coated Ni by Atomic Layer Deposition, crystalline as-deposited. • Progressive transformation into a complex surface stable in molten carbonates. • Lower Ni solubility with CeO2 protective coating. • Feasibility of CeO2 coating in Molten Carbonate Fuel Cell cathode conditions. - Abstract: In order to increase the lifetime and performance of the molten carbonate fuel cell, it is compulsory to control the corrosion and dissolution of the state of the art porous nickel oxide cathode. A protective coating constituted by more stable oxides appears to be the best approach. Previous research on CeO2 coatings obtained by DC reactive magnetron sputtering to protect the Molten carbonate fuel cell cathode gave promising results but it was necessary to improve the coating adhesion. In this paper Atomic Layer Deposition, producing high quality, homogeneous and conformal layers, was used to obtain thin layers of CeO2 (20 nm and 120 nm) deposited over porous nickel. CeO2-Ni coated samples were tested as cathodes in Li2CO3-K2CO3 (62-38 mol %) eutectic mixture under standard cathode atmosphere (CO2/air 30:70 vol. %). Structural and morphological characterizations of the nickel coated cathode before and after electrochemical tests in the molten carbonate melt are reported together with the Open Circuit Potential evolution all over 230 h for both the bare porous nickel and the CeO2-coated samples

  20. Thermal Expansion Coefficients of Thin Crystal Films

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The formulas for atomic displacements and Hamiltonian of a thin crystal film in phonon occupation number representation are obtained with the aid of Green's function theory. On the basis of these results, the formulas for thermal expansion coefficients of the thin crystal film are derived with the perturbation theory, and the numerical calculations are carried out. The results show that the thinner films have larger thermal expansion coefficients.

  1. Slip-controlled thin film dynamics

    OpenAIRE

    Fetzer, R.; Rauscher, M; Münch, A.; Wagner, B. A.; Jacobs, K.

    2006-01-01

    In this study, we present a novel method to assess the slip length and the viscosity of thin films of highly viscous Newtonian liquids. We quantitatively analyse dewetting fronts of low molecular weight polystyrene melts on Octadecyl- (OTS) and Dodecyltrichlorosilane (DTS) polymer brushes. Using a thin film (lubrication) model derived in the limit of large slip lengths, we can extract slip length and viscosity. We study polymer films with thicknesses between 50 nm and 230 nm and various tempe...

  2. BDS thin film damage competition

    Energy Technology Data Exchange (ETDEWEB)

    Stolz, C J; Thomas, M D; Griffin, A J

    2008-10-24

    A laser damage competition was held at the 2008 Boulder Damage Symposium in order to determine the current status of thin film laser resistance within the private, academic, and government sectors. This damage competition allows a direct comparison of the current state-of-the-art of high laser resistance coatings since they are all tested using the same damage test setup and the same protocol. A normal incidence high reflector multilayer coating was selected at a wavelength of 1064 nm. The substrates were provided by the submitters. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials, and layer count will also be shared.

  3. Thin-film optical shutter

    Science.gov (United States)

    Matlow, S. L.

    1981-02-01

    The ideal solution to the excessive solar gain problem is an optical shutter, a device which switches from being highly transmissive to solar radiation to being highly reflective to solar radiation when a critical temperature is reached in the enclosure. The switching occurs because one or more materials in the device undergo a phase transition at the critical temperature. A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, was chosen as the one most likely to meet all of the requirements of the thin film optical shutter project (TFOS). The reason for this choice is explored. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a quantum mechanical method, the equilibrium bond length (EBL) theory, was developed. Some results of EBL theory are included.

  4. Magneto-Optical Thin Films for On-Chip Monolithic Integration of Non-Reciprocal Photonic Devices

    Directory of Open Access Journals (Sweden)

    Mehmet Cengiz Onbasli

    2013-11-01

    Full Text Available Achieving monolithic integration of nonreciprocal photonic devices on semiconductor substrates has been long sought by the photonics research society. One way to achieve this goal is to deposit high quality magneto-optical oxide thin films on a semiconductor substrate. In this paper, we review our recent research activity on magneto-optical oxide thin films toward the goal of monolithic integration of nonreciprocal photonic devices on silicon. We demonstrate high Faraday rotation at telecommunication wavelengths in several novel magnetooptical oxide thin films including Co substituted CeO2−δ, Co- or Fe-substituted SrTiO3−δ, as well as polycrystalline garnets on silicon. Figures of merit of 3~4 deg/dB and 21 deg/dB are achieved in epitaxial Sr(Ti0.2Ga0.4Fe0.4O3−δ and polycrystalline (CeY2Fe5O12 films, respectively. We also demonstrate an optical isolator on silicon, based on a racetrack resonator using polycrystalline (CeY2Fe5O12/silicon strip-loaded waveguides. Our work demonstrates that physical vapor deposited magneto-optical oxide thin films on silicon can achieve high Faraday rotation, low optical loss and high magneto-optical figure of merit, therefore enabling novel high-performance non-reciprocal photonic devices monolithically integrated on semiconductor substrates.

  5. Plasmonic modes in thin films: quo vadis?

    Directory of Open Access Journals (Sweden)

    AntonioPolitano

    2014-07-01

    Recent calculations indicate the emergence of acoustic surface plasmons (ASP in Ag thin films exhibiting quantum well states and in graphene films. The slope of the dispersion of ASP decreases with film thickness. We also discuss open issues in research on plasmonic modes in graphene/metal interfaes.

  6. Magnetization in permalloy thin films

    Indian Academy of Sciences (India)

    Rachana Gupta; Mukul Gupta; Thomas Gutberlet

    2008-11-01

    Thin films of permalloy (Ni80Fe20) were prepared using an Ar+N2 mixture with magnetron sputtering technique at ambient temperature. The film prepared with only Ar gas shows reflections corresponding to the permalloy phase in X-ray diffraction (XRD) pattern. The addition of nitrogen during sputtering results in broadening of the peaks in XRD pattern, which finally leads to an amorphous phase. The - loop for the sample prepared with only Ar gas is matching well with the values obtained for the permalloy. For the samples prepared with increased nitrogen partial pressure the magnetic moment decreased rapidly and the values of coercivity increased. The polarized neutron reflectivity measurements (PNR) were performed in the sample prepared with only Ar gas and with nitrogen partial pressure of 5 and 10%. It was found that the spin-up and spin-down reflectivities show exactly similar reflectivity for the sample prepared with Ar gas alone, while PNR measurements on 5 and 10% sample show splitting in the spin-up and spin-down reflectivity.

  7. TiO2 thin film photocatalyst

    Institute of Scientific and Technical Information of China (English)

    YU Jiaguo

    2004-01-01

    It is well known that the photocatalytic activity of TiO2 thin films strongly depends on the preparing methods and post-treatment conditions, since they have a decisive influence on the chemical and physical properties of TiO2 thin films.Therefore, it is necessary to elucidate the influence of the preparation process and post-treatment conditions on the photocatalytic activity and surface microstructures of the films. This review deals with the preparation of TiO2 thin film photocatalysts by wet-chemical methods (such as sol-gel, reverse micellar and liquid phase deposition) and the comparison of various preparation methods as well as their advantage and disadvantage. Furthermore, it is discussed that the advancement of photocatalytic activity, super-hydrophilicity and bactericidal activity of TiO2 thin film photocatalyst in recent years.

  8. Alumina Thin Film Growth: Experiments and Modeling

    OpenAIRE

    Wallin, Erik

    2007-01-01

    The work presented in this thesis deals with experimental and theoretical studies related to the growth of crystalline alumina thin films. Alumina, Al2O3, is a polymorphic material utilized in a variety of applications, e.g., in the form of thin films. Many of the possibilities of alumina, and the problems associated with thin film synthesis of the material, are due to the existence of a range of different crystalline phases. Controlling the formation of the desired phase and the transformati...

  9. Electrochromism of amorphous ruthenium oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Se-Hee; Liu, Ping; Tracy, C. Edwin; Deb, Satyen K. [National Renewable Energy Laboratory, Center for Basic Sciences, 1617 Cole Boulevard, Golden, CO 80401 (United States); Cheong, Hyeonsik M. [Sogang University, Shinsoo-Dong, Seoul 121-742 (Korea, Republic of)

    2003-12-01

    We report on the electrochromic behavior of amorphous ruthenium oxide thin films and their electrochemical characteristics for use as counterelectrodes for electrochromic devices. Hydrous ruthenium oxide thin films were prepared by cyclic voltammetry on ITO coated glass substrates from an aqueous ruthenium chloride solution. The cyclic voltammograms of this material show the capacitive behavior including two redox reaction peaks in each cathodic and anodic scan. The ruthenium oxide thin film electrode exhibits a 50% modulation of optical transmittance at 670 nm wavelength with capacitor charge/discharge.

  10. Technology of Environmental Thin Film

    International Nuclear Information System (INIS)

    This book indicates environment and surface engineering with technical term, the newest and eco-friendly technology, surface engineering and thick film, technology of surface analysis and reality test, present condition of electronic component in business, physical vapor deposition method, chemical vapor deposition method, plasma assisted etching, part materials of every functional film and manufacturing method, film resistance materials, film gene materials, total using of various film, film superconductivity materials, and photo electricity film.

  11. Studies of solution deposited cerium oxide thin films on textured Ni-alloy substrates for YBCO superconductor

    International Nuclear Information System (INIS)

    Cerium oxide (CeO2) buffer layers play an important role for the development of YBa2Cu3O7-x (YBCO) based superconducting tapes using the rolling assisted biaxially textured substrates (RABiTS) approach. The chemical solution deposition (CSD) approach has been used to grow epitaxial CeO2 films on textured Ni-3 at.% W alloy substrates with various starting precursors of ceria. Precursors such as cerium acetate, cerium acetylacetonate, cerium 2-ethylhexanoate, cerium nitrate, and cerium trifluoroacetate were prepared in suitable solvents. The optimum growth conditions for these cerium precursors were Ar-4% H2 gas processing atmosphere, solution concentration levels of 0.2-0.5 M, a dwell time of 15 min, and a process temperature range of 1050-1150 deg. C. X-ray diffraction, AFM, SEM, and optical microscopy were used to characterize the CeO2 films. Highly textured CeO2 layers were obtained on Ni-W substrates with both cerium acetate and cerium acetylacetonate as starting precursors. YBCO films with a J c of 1.5 MA/cm2 were obtained on cerium acetylacetonate-based CeO2 films with sputtered YSZ and CeO2 cap layers

  12. CeO2 nanoparticles for high performance supercapacitor electrode

    International Nuclear Information System (INIS)

    Cerium Oxide plays a vital role in rising technologies for energy-related applications. In this study, CeO2 nanoparticles have been successfully synthesized by microwave irradiation method and its capacitance performance is further investigated. Prepared nanoparticles were analysed by X-Ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). X-ray diffraction analysis confirms that CeO2 Nanoparticles in cubic phase and the grain size was calculated to be 15 nm using Debye-Scherrer formula. The FTIR spectrum of the CeO2 exhibits the stretching vibration of Ce-O at about 601 cm-1. The SEM analysis shows the irregular spherical morphology with some of the particles agglomerated. Electrochemical characterization of the sample was performed using a standard three electrode cell configuration. Cyclic Voltammogram (CV) and galvanostatic (GV) charge-discharge measurements demonstrated that the CeO2 electrode exhibited superior capacitive properties in 1 M Na2SO4 aqueous solution within the potential range -0.2V to 1.5V The discharge curves are linear in the total range of potential with constant slopes at a constant current of 0.9 A/g showing perfect capacitive behavior. These findings can open up new opportunities for CeO2 nanoparticles in constructing the high-performance electrochemical supercapacitors as well as other energy storage devices. (author)

  13. Immobilization of metalloporphyrins on CeO2@SiO2 with a core-shell structure prepared via microemulsion method for catalytic oxidation of ethylbenzene

    Institute of Scientific and Technical Information of China (English)

    沈丹华; 吉琳韬; 付玲玲; 董旭龙; 刘志刚; 刘强; 刘世明

    2015-01-01

    CeO2@SiO2 core−shell nanoparticles were prepared by microemulsion method, and metalloporphyrins were immobilized on the CeO2@SiO2 core−shell nanoparticles surface via amide bond. The supported metalloporphyrin catalysts were characterized by N2 adsorption−desorption isotherm (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), ultraviolet and visible spectroscopy (UV-Vis), and Fourier transform infrared spectroscopy (FT-IR). The results show that the morphology of CeO2@SiO2 nanoparticles is core−shell microspheres with about 30 nm in diameter, and metalloporphyrins are immobilized on the CeO2@SiO2 core−shell nanoparticles via amide bond. Especially, the core−shell structure contains multi CeO2 core and thin SiO2 shell, which may benefit the synergistic effect between the CeO2 core and the porphyrin anchored on the very thin SiO2 shell. As a result, this supported metalloporphyrin catalysts present comparably high catalytic activity and stability for oxidation of ethylbenzene with molecular oxygen, namely, ethylbenzene conversion remains around 12% with identical selectivity of about 80%for acetophenone even after six-times reuse of the catalyst.

  14. Research on Advanced Thin Film Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Goldner, Ronald B. [Tufts Univ., Medford, MA (United States)

    2003-11-24

    During the past 7 years, the Tufts group has been carrying out research on advanced thin film batteries composed of a thin film LiCo02 cathode (positive electrode), a thin film LiPON (lithium phosphorous oxynitride) solid electrolyte, and a thin film graphitic carbon anode (negative electrode), under grant DE FG02-95ER14578. Prior to 1997, the research had been using an rfsputter deposition process for LiCoOi and LiPON and an electron beam evaporation or a controlled anode arc evaporation method for depositing the carbon layer. The pre-1997 work led to the deposition of a single layer cell that was successfully cycled for more than 400 times [1,2] and the research also led to the deposition of a monolithic double-cell 7 volt battery that was cycled for more than 15 times [3]. Since 1997, the research has been concerned primarily with developing a research-worthy and, possibly, a production-worthy, thin film deposition process, termed IBAD (ion beam assisted deposition) for depositing each ofthe electrodes and the electrolyte of a completely inorganic solid thin film battery. The main focus has been on depositing three materials - graphitic carbon as the negative electrode (anode), lithium cobalt oxide (nominally LiCoCb) as the positive electrode (cathode), and lithium phosphorus oxynitride (LiPON) as the electrolyte. Since 1998, carbon, LiCoOa, and LiPON films have been deposited using the IBAD process with the following results.

  15. Analysis of angular dependence of pinning mechanisms on Ca-substituted YBa2Cu3O7-δ epitaxial thin films

    International Nuclear Information System (INIS)

    The critical current density Jc as a function of the temperature T, magnetic field intensity H and angle θ between the direction of applied magnetic field and the c-axis of the samples was measured on epitaxial 10 at.% Ca-substituted YBa2Cu3O7-δ (YCBCO) thin films grown by the pulsed laser deposition technique on (001)-SrTiO3 (STO) and CeO2 buffered r-cut Al2O3 (CAO) substrates. Films exhibited comparable values of critical temperature (Tc∼78 K) while higher self-field Jc values for SrTiO3 were observed. Dissipation regimes related to growth boundary and intra-grain pinning mechanisms showed a qualitatively similar contribution for YCBCO films deposited on both substrates when the applied magnetic field direction is parallel to the c-axis (θ = 00). However, a weaker efficiency of pinning related to growth boundaries as well as a wider field range where this dissipation mechanism is active were observed for films grown on CeO2-buffered sapphire. These films exhibited a broad peak centred at θ = 00 in the Jc versus angle behaviour, not observed using a SrTiO3 substrate. The analysis of the Jc(H) dependences collected at θ = 900 revealed that this feature can be partially ascribed to a dramatic decrease of the intrinsic pinning efficiency

  16. Permanent laser conditioning of thin film optical materials

    Science.gov (United States)

    Wolfe, C. Robert; Kozlowski, Mark R.; Campbell, John H.; Staggs, Michael; Rainer, Frank

    1995-01-01

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold.

  17. Phase transformation kinetics in thin films

    International Nuclear Information System (INIS)

    This book contains papers presented at the materials Research Society Symposium on Phase Transformations Kinetics in Thin Films held in Anaheim, California from April 29 through May 1, 1991. This symposium provided a multidisciplinary forum for explorations, on experimental and theoretical levels, of thin film reactions and stability, phase nucleation and growth, and amorphization. The papers in this volume, refereed by the peer review process, are organized according to materials and techniques and do not reflect the order of presentations at the symposium. Symposium sessions were organized in the areas of thin-film crystallization, solid-state amorphization, interfacial reactions, solid-state transformations, phase-change optical media and ferroelectric thin films. Contributed papers ranged from theoretical determination of the limits to melt nucleation to commercial concerns of processing techniques for specific properties. Despite this breadth, the similarity of experimental techniques and thermodynamic underpinnings for most of the materials provided a common basis for discussions

  18. Highly stretchable wrinkled gold thin film wires

    International Nuclear Information System (INIS)

    With the growing prominence of wearable electronic technology, there is a need to improve the mechanical reliability of electronics for more demanding applications. Conductive wires represent a vital component present in all electronics. Unlike traditional planar and rigid electronics, these new wearable electrical components must conform to curvilinear surfaces, stretch with the body, and remain unobtrusive and low profile. In this paper, the piezoresistive response of shrink induced wrinkled gold thin films under strain demonstrates robust conductive performance in excess of 200% strain. Importantly, the wrinkled metallic thin films displayed negligible change in resistance of up to 100% strain. The wrinkled metallic wires exhibited consistent performance after repetitive strain. Importantly, these wrinkled thin films are inexpensive to fabricate and are compatible with roll to roll manufacturing processes. We propose that these wrinkled metal thin film wires are an attractive alternative to conventional wires for wearable applications

  19. Highly stretchable wrinkled gold thin film wires

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joshua, E-mail: joshuk7@uci.edu; Park, Sun-Jun; Nguyen, Thao [Department of Chemical Engineering and Materials Science, University of California, Irvine, California 92697 (United States); Chu, Michael [Department of Biomedical Engineering, University of California, Irvine, California 92697 (United States); Pegan, Jonathan D. [Department of Materials and Manufacturing Technology, University of California, Irvine, California 92697 (United States); Khine, Michelle, E-mail: mkhine@uci.edu [Department of Chemical Engineering and Materials Science, University of California, Irvine, California 92697 (United States); Department of Biomedical Engineering, University of California, Irvine, California 92697 (United States)

    2016-02-08

    With the growing prominence of wearable electronic technology, there is a need to improve the mechanical reliability of electronics for more demanding applications. Conductive wires represent a vital component present in all electronics. Unlike traditional planar and rigid electronics, these new wearable electrical components must conform to curvilinear surfaces, stretch with the body, and remain unobtrusive and low profile. In this paper, the piezoresistive response of shrink induced wrinkled gold thin films under strain demonstrates robust conductive performance in excess of 200% strain. Importantly, the wrinkled metallic thin films displayed negligible change in resistance of up to 100% strain. The wrinkled metallic wires exhibited consistent performance after repetitive strain. Importantly, these wrinkled thin films are inexpensive to fabricate and are compatible with roll to roll manufacturing processes. We propose that these wrinkled metal thin film wires are an attractive alternative to conventional wires for wearable applications.

  20. Electroless plating of thin gold films directly onto silicon nitride thin films and into micropores.

    Science.gov (United States)

    Whelan, Julie C; Karawdeniya, Buddini Iroshika; Bandara, Y M Nuwan D Y; Velleco, Brian D; Masterson, Caitlin M; Dwyer, Jason R

    2014-07-23

    A method to directly electrolessly plate silicon-rich silicon nitride with thin gold films was developed and characterized. Films with thicknesses coating planar, curved, and line-of-sight-obscured silicon nitride surfaces. PMID:24999923

  1. High temperature superconducting thin film microwave filters

    International Nuclear Information System (INIS)

    Low loss thin films of high temperature superconductors (HTSC) on MgO as well as LaAlO3 substrates has been successfully developed. This effort aims at the development of application oriented innovations, such as HTSC based passive microwave devices. As an initial attempt in developing microwave devices, we have designed, fabricated and tested HTSC microstrip resonators at X-band using YBCO thin films on LaAlO3 substrates

  2. Advances in CZTS thin films and nanostructured

    Science.gov (United States)

    Ali, N.; Ahmed, R.; Bakhtiar-Ul-Haq; Shaari, A.

    2015-06-01

    Already published data for the optical band gap (Eg) of thin films and nanostructured copper zinc tin sulphide (CZTS) have been reviewed and combined. The vacuum (physical) and non-vacuum (chemical) processes are focused in the study for band gap comparison. The results are accumulated for thin films and nanostructured in different tables. It is inferred from the re- view that the nanostructured material has plenty of worth by engineering the band gap for capturing the maximum photons from solar spectrum.

  3. Laser-annealing of thin semiconductor films

    OpenAIRE

    Boneberg, Johannes; Nedelcu, Johann; Bucher, Ernst; Leiderer, Paul

    1994-01-01

    Optical reflectivity and transmissivity measurements have been used to investigate the dynamics of melting and recrystallisation of thin films of Si and Ge after laser-annealing with a ns Nd:YAG-laser pulse. We report on temperature dependent changes of the reflectivity of the liquid phase above and below the melting point and on various nucleation and solidification scenarios in thin film, depending on the energy density of the amding laser.

  4. Characteristics and durability of fluoropolymer thin films

    OpenAIRE

    Cheneler, David; Bowen, James; Evans, Stephen D.; Górzny, Marcin; Adams, Michael J; Ward, Michael C.L.

    2011-01-01

    The use of plasma-polymerised fluoropolymer (CFxOy) thin films in the manufacture of microelectromechanical systems (MEMS) devices is well-established, being employed in the passivation step of the deep reactive ion etching (DRIE) process, for example. This paper presents an investigation of the effect of exposure to organic and aqueous liquid media on plasma polymerised CFxOy thin films. Atomic force microscopy (AFM), scanning electron microscopy (SEM), ellipsometry, X-ray photoelectron spec...

  5. Thin film description by wavelet coefficients statistics

    Czech Academy of Sciences Publication Activity Database

    Boldyš, Jiří; Hrach, R.

    2005-01-01

    Roč. 55, č. 1 (2005), s. 55-64. ISSN 0011-4626 Grant ostatní: GA UK(CZ) 173/2003 Institutional research plan: CEZ:AV0Z10750506 Keywords : thin films * wavelet transform * descriptors * histogram model Subject RIV: BD - Theory of Information Impact factor: 0.360, year: 2005 http://library.utia.cas.cz/separaty/2009/ZOI/boldys-thin film description by wavelet coefficients statistics .pdf

  6. Epitaxy, thin films and superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Jagd Christensen, Morten

    1997-05-01

    This report is the result of structural investigations of 3d transition metal superlattices consisting of Fe/V, Cr/Mn, V/Mn and Fe/Mn, and a structural and magnetic study of a series of Ho/Pr alloys. The work includes preparation and characterization of substrates as well as growth of thin films and Fe/V superlattices by molecular beam epitaxy, including in-situ characterization by reflection high energy electron diffraction and Auger electron spectroscopy. Structural characterization has been done by x-ray diffraction and neutron diffraction. The x-ray diffraction experiments have been performed on the rotating copper anode at Risoe, and at synchrotron facilities in Hamburg and Brookhaven, and the neutron scattering was done at the Danish research reactor DR3 at Risoe. In addition to longitudinal scans, giving information about the structural parameters in the modulation direction, non-specular scans were also performed. This type of scans gives information about in-plane orientation and lattice parameters. From the analysis, structural information is obtained about lattice parameters, epitaxial strain, coherence lengths and crystallographic orientation for the superlattice systems, except Fe/Mn superlattices, which could not be modelled. For the Ho/Pr alloys, x-ray magnetic scattering was performed, and the crystal and magnetic structure was investigated. (au) 14 tabs.; 58 ills., 96 refs.

  7. Studies in thin film flows

    CERN Document Server

    McKinley, I S

    2000-01-01

    the general case of non-zero capillary number numerically. Using the lubrication approximation to the Navier-Stokes equations we investigate the evolution and stability of a thin film of incompressible Newtonian fluid on a planar substrate subjected to a jet of air blowing normally to the substrate. For the simple model of the air jet we adopt, the initially axisymmetric problems we study are identical to those of a drop spreading on a turntable rotating at constant angular velocity (the simplest model for spin coating). We consider both drops without a dry patch (referred to as 'non-annular') and drops with a dry patch at their centre (referred to as 'annular'). First, both symmetric two-dimensional and axisymmetric three-dimensional drops are considered in the quasi-static limit of small capillary number. The evolution of both non-annular and annular drops and the stability of equilibrium solutions to small perturbations with zero wavenumber are determined. Using a specially developed finite-difference code...

  8. Epitaxy, thin films and superlattices

    International Nuclear Information System (INIS)

    This report is the result of structural investigations of 3d transition metal superlattices consisting of Fe/V, Cr/Mn, V/Mn and Fe/Mn, and a structural and magnetic study of a series of Ho/Pr alloys. The work includes preparation and characterization of substrates as well as growth of thin films and Fe/V superlattices by molecular beam epitaxy, including in-situ characterization by reflection high energy electron diffraction and Auger electron spectroscopy. Structural characterization has been done by x-ray diffraction and neutron diffraction. The x-ray diffraction experiments have been performed on the rotating copper anode at Risoe, and at synchrotron facilities in Hamburg and Brookhaven, and the neutron scattering was done at the Danish research reactor DR3 at Risoe. In addition to longitudinal scans, giving information about the structural parameters in the modulation direction, non-specular scans were also performed. This type of scans gives information about in-plane orientation and lattice parameters. From the analysis, structural information is obtained about lattice parameters, epitaxial strain, coherence lengths and crystallographic orientation for the superlattice systems, except Fe/Mn superlattices, which could not be modelled. For the Ho/Pr alloys, x-ray magnetic scattering was performed, and the crystal and magnetic structure was investigated. (au)

  9. Superconducting thin-film gradiometer

    International Nuclear Information System (INIS)

    We describe the design, fabrication, and performance of planar thin-film dc SQUID's and planar gradiometers in which a dc SQUID is incorporated as a null detector. Each gradiometer was fabricated on a planar substrate and measured an off-diagonal component of changes in the magnetic field gradient. The gradiometer with the highest sensitivity had 127 x 33-mm loops that could be connected in parallel or in series: The sensitivities were 2.1 x 10-13 and 3.7 x 10-13 T m-1 Hz/sup -1/2/, respectively. The intrinsic balance of the gradiometers was about 100 ppm for fields parallel to their plane, and a balance of about 1 ppm could be achieved for fields perpendicular to their plane. When the series-loop gradiometer was rotated through 3600 in the earth's field, the output returned to its initial value to within an amount corresponding to a balance of 1 ppm. Possible improvements in sensitivity are discussed

  10. Microstructural evolution of tungsten oxide thin films

    Science.gov (United States)

    Hembram, K. P. S. S.; Thomas, Rajesh; Rao, G. Mohan

    2009-10-01

    Tungsten oxide thin films are of great interest due to their promising applications in various optoelectronic thin film devices. We have investigated the microstructural evolution of tungsten oxide thin films grown by DC magnetron sputtering on silicon substrate. The structural characterization and surface morphology were carried out using X-ray diffraction and Scanning Electron Microscopy (SEM). The as deposited films were amorphous, where as, the films annealed above 400 °C were crystalline. In order to explain the microstructural changes due to annealing, we have proposed a "instability wheel" model for the evolution of the microstructure. This model explains the transformation of mater into various geometries within them selves, followed by external perturbation.

  11. Microstructural evolution of tungsten oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hembram, K.P.S.S., E-mail: hembram@isu.iisc.ernet.in [Department of Instrumentation, Indian Institute of Science, Bangalore - 560 012 (India); Theoretical Science Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore - 560064 (India); Thomas, Rajesh; Rao, G. Mohan [Department of Instrumentation, Indian Institute of Science, Bangalore - 560 012 (India)

    2009-10-30

    Tungsten oxide thin films are of great interest due to their promising applications in various optoelectronic thin film devices. We have investigated the microstructural evolution of tungsten oxide thin films grown by DC magnetron sputtering on silicon substrate. The structural characterization and surface morphology were carried out using X-ray diffraction and Scanning Electron Microscopy (SEM). The as deposited films were amorphous, where as, the films annealed above 400 deg. were crystalline. In order to explain the microstructural changes due to annealing, we have proposed a 'instability wheel' model for the evolution of the microstructure. This model explains the transformation of mater into various geometries within them selves, followed by external perturbation.

  12. First principles study of the magnetism driven by cation defects in CeO2: the important role of O2p states

    Institute of Scientific and Technical Information of China (English)

    Lu Zhan-Sheng; Ma Dong-Wei; Zhang Jing; Xu Guo-Liang; Yang Zong-Xian

    2012-01-01

    The magnetism driven by cation defects in undoped CeO2 bulk and thin films is studied by the density functional theory corrected for on-site Coulomb interactions (DFT+U) with U =5 eV for the Ce4f states and U =7 eV for the O2p states.It is found that the Ce vacancies can induce a magnetic moment of the ~ 4 μB/supercell,which arises mainly from the 2p hole state of the nearest neighbouring O atom (~ 1 μB on per oxygen) to the Ce vacancy.The effect of the methodology is investigated,indicating that U =7 eV for the O2p state is necessary to obtain the localized O2p hole state in defective ceria with cation vacancies.

  13. First principles study of the magnetism driven by cation defects in CeO2: the important role of O2p states

    International Nuclear Information System (INIS)

    The magnetism driven by cation defects in undoped CeO2 bulk and thin films is studied by the density functional theory corrected for on-site Coulomb interactions (DFT+U) with U = 5 eV for the Ce4f states and U = 7 eV for the O2p states. It is found that the Ce vacancies can induce a magnetic moment of the ∼ 4 μB/supercell, which arises mainly from the 2p hole state of the nearest neighbouring O atom (∼ 1 μB on per oxygen) to the Ce vacancy. The effect of the methodology is investigated, indicating that U = 7 eV for the O2p state is necessary to obtain the localized O2p hole state in defective ceria with cation vacancies. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  14. Thin-film crystalline silicon solar cells

    CERN Document Server

    Brendel, Rolf

    2011-01-01

    This introduction to the physics of silicon solar cells focuses on thin cells, while reviewing and discussing the current status of the important technology. An analysis of the spectral quantum efficiency of thin solar cells is given as well as a full set of analytical models. This is the first comprehensive treatment of light trapping techniques for the enhancement of the optical absorption in thin silicon films.

  15. Magnetic behaviors of cerium oxide-based thin films deposited using electrochemical method

    International Nuclear Information System (INIS)

    Zn and Co multi-doped CeO2 thin films have been prepared using an anodic electrochemical method. The structures and magnetic behaviors are characterized by several techniques, in which the oxygen states in the lattice and the absorptive oxygen bonds at the surface are carefully examined. The absorptive oxygen bond is about 50% of the total oxygen bond by using a semi-quantitative method. The value of actual stoichiometry δ' is close to 2. The experimental results indicate that the thin films are of a cerium oxide-based solid solution with few oxygen vacancies in the lattice and many absorptive oxygen bonds at the surface. Week ferromagnetic behaviors were evidenced by observed M—H hysteresis loops at room temperature. Furthermore, an evidence of relative ferromagnetic contributions was revealed by the temperature dependence of magnetization. It is believed that the ferromagnetic contributions exhibited in the M—H loops originate from the absorptive oxygen on the surface rather than the oxygen vacancies in the lattice. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  16. Post deposition purification of PTCDA thin films

    International Nuclear Information System (INIS)

    The decomposition of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) molecules during evaporation of unpurified raw material in ultra high vacuum was studied. The fragments were identified by mass spectrometry and the influence of these fragments and further contaminations of the raw material on the electronic structure of PTCDA thin films was measured by photoemission spectroscopy. Annealing of contaminated PTCDA films was tested as cheap and easy to perform method for (partial) post deposition purification of the contaminated films

  17. Polymer surfaces, interfaces and thin films

    International Nuclear Information System (INIS)

    Neutron reflectometry can be used in various ways to investigate surfaces, interfaces and thin films of polymers. Its potential comes mostly from the possibilities offered by selective deuteration, where a particular component can be made visible with respect to its activity at the interface. In addition the depth resolution is much better than with most other direct techniques, and details of the profiles may be resolved. Several examples will be discussed including the segment diffusion at the interface between two polymer films, the determination of the narrow interfaces between incompatible polymer blends and the development of order in thin diblock copolymer films. (author) 10 figs., 2 tabs., 38 refs

  18. Thin-film Rechargeable Lithium Batteries

    Science.gov (United States)

    Dudney, N. J.; Bates, J. B.; Lubben, D.

    1995-06-01

    Thin film rechargeable lithium batteries using ceramic electrolyte and cathode materials have been fabricated by physical deposition techniques. The lithium phosphorous oxynitride electrolyte has exceptional electrochemical stability and a good lithium conductivity. The lithium insertion reaction of several different intercalation materials, amorphous V{sub 2}O{sub 5}, amorphous LiMn{sub 2}O{sub 4}, and crystalline LiMn{sub 2}O{sub 4} films, have been investigated using the completed cathode/electrolyte/lithium thin film battery.

  19. Polymer surfaces, interfaces and thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stamm, M. [Max-Planck-Institut fuer Polymerforschung, Mainz (Germany)

    1996-11-01

    Neutron reflectometry can be used in various ways to investigate surfaces, interfaces and thin films of polymers. Its potential comes mostly from the possibilities offered by selective deuteration, where a particular component can be made visible with respect to its activity at the interface. In addition the depth resolution is much better than with most other direct techniques, and details of the profiles may be resolved. Several examples will be discussed including the segment diffusion at the interface between two polymer films, the determination of the narrow interfaces between incompatible polymer blends and the development of order in thin diblock copolymer films. (author) 10 figs., 2 tabs., 38 refs.

  20. Thin Ice Films at Mineral Surfaces.

    Science.gov (United States)

    Yeşilbaş, Merve; Boily, Jean-François

    2016-07-21

    Ice films formed at mineral surfaces are of widespread occurrence in nature and are involved in numerous atmospheric and terrestrial processes. In this study, we studied thin ice films at surfaces of 19 synthetic and natural mineral samples of varied structure and composition. These thin films were formed by sublimation of thicker hexagonal ice overlayers mostly produced by freezing wet pastes of mineral particles at -10 and -50 °C. Vibration spectroscopy revealed that thin ice films contained smaller populations of strongly hydrogen-bonded water molecules than in hexagonal ice and liquid water. Thin ice films at the surfaces of the majority of minerals considered in this work [i.e., metal (oxy)(hydr)oxides, phyllosilicates, silicates, volcanic ash, Arizona Test Dust] produced intense O-H stretching bands at ∼3400 cm(-1), attenuated bands at ∼3200 cm(-1), and liquid-water-like bending band at ∼1640 cm(-1) irrespective of structure and composition. Illite, a nonexpandable phyllosilicate, is the only mineral that stabilized a form of ice that was strongly resilient to sublimation in temperatures as low as -50 °C. As mineral-bound thin ice films are the substrates upon which ice grows from water vapor or aqueous solutions, this study provides new constraints from which their natural occurrences can be understood. PMID:27377606

  1. Carrier lifetimes in thin-film photovoltaics

    Science.gov (United States)

    Baek, Dohyun

    2015-09-01

    The carrier lifetimes in thin-film solar cells are reviewed and discussed. Shockley-Read-Hall recombination is dominant at low carrier density, Auger recombination is dominant under a high injection condition and high carrier density, and surface recombination is dominant under any conditions. Because the surface photovoltage technique is insensitive to the surface condition, it is useful for bulk lifetime measurements. The photoconductance decay technique measures the effective recombination lifetime. The time-resolved photoluminescence technique is very useful for measuring thin-film semiconductor or solar-cell materials lifetime, because the sample is thin, other techniques are not suitable for measuring the lifetime. Many papers have provided time-resolved photoluminescence (TRPL) lifetimes for copper-indium-gallium-selenide (CIGS) and CdTe thin-film solar cell. The TRPL lifetime strongly depends on open-circuit voltage and conversion efficiency; however, the TRPL life time is insensitive to the short-circuit current.

  2. Nanostructured thin films as functional coatings

    Energy Technology Data Exchange (ETDEWEB)

    Lazar, Manoj A; Tadvani, Jalil K; Tung, Wing Sze; Lopez, Lorena; Daoud, Walid A, E-mail: Walid.Daoud@sci.monash.edu.au [School of Applied Sciences and Engineering, Monash University, Churchill, VIC 3842 (Australia)

    2010-06-15

    Nanostructured thin films is one of the highly exploiting research areas particularly in applications such as photovoltaics, photocatalysis and sensor technologies. Highly tuned thin films, in terms of thickness, crystallinity, porosity and optical properties, can be fabricated on different substrates using the sol-gel method, chemical solution deposition (CSD), electrochemical etching, along with other conventional methods such as chemical vapour deposition (CVD) and physical vapour deposition (PVD). The above mentioned properties of these films are usually characterised using surface analysis techniques such as XRD, SEM, TEM, AFM, ellipsometry, electrochemistry, SAXS, reflectance spectroscopy, STM, XPS, SIMS, ESCA, X-ray topography and DOSY-NMR. This article presents a short review of the preparation and characterisation of thin films of nanocrystalline titanium dioxide and modified silicon as well as their application in solar cells, water treatment, water splitting, self cleaning fabrics, sensors, optoelectronic devices and lab on chip systems.

  3. Nanostructured thin films as functional coatings

    International Nuclear Information System (INIS)

    Nanostructured thin films is one of the highly exploiting research areas particularly in applications such as photovoltaics, photocatalysis and sensor technologies. Highly tuned thin films, in terms of thickness, crystallinity, porosity and optical properties, can be fabricated on different substrates using the sol-gel method, chemical solution deposition (CSD), electrochemical etching, along with other conventional methods such as chemical vapour deposition (CVD) and physical vapour deposition (PVD). The above mentioned properties of these films are usually characterised using surface analysis techniques such as XRD, SEM, TEM, AFM, ellipsometry, electrochemistry, SAXS, reflectance spectroscopy, STM, XPS, SIMS, ESCA, X-ray topography and DOSY-NMR. This article presents a short review of the preparation and characterisation of thin films of nanocrystalline titanium dioxide and modified silicon as well as their application in solar cells, water treatment, water splitting, self cleaning fabrics, sensors, optoelectronic devices and lab on chip systems.

  4. Interface-engineered resistive switching: CeO(2) nanocubes as high-performance memory cells.

    Science.gov (United States)

    Younis, Adnan; Chu, Dewei; Mihail, Ionsecu; Li, Sean

    2013-10-01

    We reported a novel and facile approach to fabricate self-assembled CeO2 nanocube-based resistive-switching memory device. The device was found to exhibit excellent bipolar resistive-switching characteristics with a high resistance state (HRS/OFF) to low resistance state (LRS/ON) ratio of 10(4), better uniformity, and stability up to 480 K. The presence of oxygen vacancies and their role was discussed to explain the resistive-switching phenomenon in the fabricated devices. Further, the effect of the film thickness on carrier concentrations and estimated electric field strength with the switching (OFF/ON) ratio were also discussed. PMID:24028707

  5. Niobium Thin Film Characterization for Thin Film Technology Used in Superconducting Radiofrequency Cavities

    Science.gov (United States)

    Dai, Yishu; Valente-Feliciano, Anne-Marie

    2015-10-01

    Superconducting RadioFrequency (SRF) penetrates about 40-100 nm of the top surface, making thin film technology possible in producing superconducting cavities. Thin film is based on the deposition of a thin Nb layer on top of a good thermal conducting material such as Al or Cu. Thin film allows for better control of the surface and has negligible response to the Earth's magnetic field, eliminating the need for magnetic shielding of the cavities. Thin film superconductivity depends heavily on coating process conditions, involving controllable parameters such as crystal plane orientation, coating temperature, and ion energy. MgO and Al2O3 substrates are used because they offer very smooth surfaces, ideal for studying film growth. Atomic Force Microscopy is used to characterize surface's morphology. It is evident that a lower nucleation energy and a long coating time increases the film quality in the r-plane sapphire crystal orientation. The quality of the film increases with thickness. Nb films coated on r-plane, grow along the (001) plane and yield a much higher RRR compared to the films grown on a- and c-planes. This information allows for further improvement on the research process for thin film technology used in superconducting cavities for the particle accelerators. National Science Foundation, Department of Energy, Jefferson Lab, Old Dominion University.

  6. Electrochemical Analysis of Conducting Polymer Thin Films

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2010-04-01

    Full Text Available Polyelectrolyte multilayers built via the layer-by-layer (LbL method has been one of the most promising systems in the field of materials science. Layered structures can be constructed by the adsorption of various polyelectrolyte species onto the surface of a solid or liquid material by means of electrostatic interaction. The thickness of the adsorbed layers can be tuned precisely in the nanometer range. Stable, semiconducting thin films are interesting research subjects. We use a conducting polymer, poly(p-phenylene vinylene (PPV, in the preparation of a stable thin film via the LbL method. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to characterize the ionic conductivity of the PPV multilayer films. The ionic conductivity of the films has been found to be dependent on the polymerization temperature. The film conductivity can be fitted to a modified Randle’s circuit. The circuit equivalent calculations are performed to provide the diffusion coefficient values.

  7. Hydrogen behavior in nanocrystalline titanium thin films

    International Nuclear Information System (INIS)

    Nanocrystalline titanium films of different thicknesses, sputtered on sapphire substrates, were charged electrochemically with hydrogen. Hydrogen absorption and the thermodynamics of the nanocrystalline Ti-H thin film system were studied using electromotive force (EMF) measurements. The phase boundaries obtained from the EMF-pressure-concentration curves were confirmed by X-ray diffraction, complemented by in situ stress measurements during hydrogen charging. The change in the stress increase with hydrogen concentration was found to be in good agreement with the obtained phase boundaries. In comparison to bulk Ti-H system, considerable changes, such as shifted phase boundaries, and narrowed and sloped miscibility gaps, were observed in Ti-H thin films. These changes vary among the films of different crystalline orientation and are attributed to both microstructural effects and stress contributions. The influence of the initial crystallographic growth orientation of Ti films on the measured thermodynamic isotherms, phase transitions and stress development is discussed in detail.

  8. Thermal conductivity of nanoscale thin nickel films

    Institute of Scientific and Technical Information of China (English)

    YUAN Shiping; JIANG Peixue

    2005-01-01

    The inhomogeneous non-equilibrium molecular dynamics (NEMD) scheme is applied to model phonon heat conduction in thin nickel films. The electronic contribution to the thermal conductivity of the film is deduced from the electrical conductivity through the use of the Wiedemann-Franz law. At the average temperature of T = 300 K, which is lower than the Debye temperature ()D = 450 K,the results show that in a film thickness range of about 1-11 nm, the calculated cross-plane thermal conductivity decreases almost linearly with the decreasing film thickness, exhibiting a remarkable reduction compared with the bulk value. The electrical and thermal conductivities are anisotropic in thin nickel films for the thickness under about 10 nm. The phonon mean free path is estimated and the size effect on the thermal conductivity is attributed to the reduction of the phonon mean free path according to the kinetic theory.

  9. Critical behavior of ferromagnetic Ising thin films

    International Nuclear Information System (INIS)

    In the present work, we study the magnetic properties and critical behavior of simple cubic ferromagnetic thin films. We simulate LxLxd films with semifree boundary conditions on the basis of the Monte Carlo method and the Ising model with nearest neighbor interactions. A Metropolis dynamics was implemented to carry out the energy minimization process. For different film thickness, in the nanometer range, we compute the temperature dependence of the magnetization, the magnetic susceptibility and the fourth order Binder's cumulant. Bulk and surface contributions of these quantities are computed in a differentiated fashion. Additionally, according to finite size scaling theory, we estimate the critical exponents for the correlation length, magnetic susceptibility, and magnetization. Results reveal a strong dependence of critical temperature and critical exponents on the film thickness. The obtained critical exponents are finally compared to those reported in literature for thin films

  10. Thermal conductivities of thin, sputtered optical films

    International Nuclear Information System (INIS)

    The normal component of thin-film thermal conductivity has been measured for the first time, to the best of our knowledge, for several advanced sputtered optical materials. Included are data for single layers of boron nitride, silicon aluminum nitride, silicon aluminum oxynitride, silicon carbide, and for dielectric-enhanced metal reflectors of the form Al(SiO2/Si3N4)n and Al(Al2O3/AlN)n. Sputtered films of more conventional materials such as SiO2, Al2O3, Ta2O5, Ti, and Si have also been measured. The data show that thin-film thermal conductivities are typically 10 to 100 times lower than conductivities for the same materials in bulk form. Structural disorder in the amorphous or fine-grained films appears to account for most of the conductivity difference. Conclusive evidence for a film--substrate interface contribution is presented

  11. Transport properties of pure and doped CeO2

    International Nuclear Information System (INIS)

    The oxides that crystallize in the fluorite structure are noted for their ability to accommodate a high degree of disorder on the oxygen sublattice. Cerium oxide is a semiconductor and ionically- conductor oxide with important electrical and chemical applications as a solid oxide fuel cell electrolyte, a catalyst for gas phase oxidation and reduction reactions, and as an oxygen buffer in the automotive 3-way catalyst. Polycrystalline samples of different grain size were prepared by uniaxial hot pressing and their sintering behavior was investigated, at various temperatures and pressures. The cerium dioxide has been prepared by this way and characterized by X-ray diffraction and transmission electron microscopy (SEM). Measurements of electronic conductivity have confirmed that electron transport in CeO2-x proceeds via a small polaron process. The electrical properties of CeO2-UO2 solid solutions are examined as a function of temperature (600 deg. C - 1400 deg. C), oxygen partial pressure (10 - 22 - 1 atm), and Ce/U ratio (CeO2- 1.65% UO2, CeO2- 5% UO2). The PO2 values were controlled by mixing Ar-O2 and CO2-H2 or Ar-H2, gases in appropriate proportions. Electrical conductivity data obtained for U-doped CeO2 solid solution were shown to be in good agreement with predictions and thereby enable derivation of a number of key parameters, including those controlling generation of oxygen Frenkel defects, doubly ionized vacancies and electrons by reduction, and electron mobilities. (authors)

  12. Surface morphology of thin films polyoxadiazoles

    Directory of Open Access Journals (Sweden)

    J. Weszka

    2011-12-01

    Full Text Available urpose: The purpose of this paper was to analyse the surface morphology of thin films polyoxadiazoles. Design/methodology/approach: SSix different polymers which belong to the group of polyoxadiazoles were dissolved in the solvent NMP. Each of these polymer was deposited on a glass substrate and a spin coating method was applied with a spin speed of 1000, 2000 and 3000 rev/min. Changes in surface topography and roughness were observed. An atomic force microscope AFM Park System has been used. Photos have been taken in noncontact mode while observing an area of 10 x 10 microns.Findings: The analysis of images has confirmed that the quality of thin films depends upon the used polymers. It was also observed that the parameters of the spin coating method have significant effect on the morphology and the surface roughness. The speed of the spin has got a strong impact on the topography of the thin films obtained.Research limitations/implications: The morphology of polyoxadiazoles thin films has been described. This paper include description how the spin speed influences the morphology of polymer thin films. In order to use a polymer thin film in photovoltaics or optoelectronics it must have a uniform thickness and a low surface roughness. Further research, in which the optical properties of thin films are investigated, is strongly recommended.Practical implications: Conductive polymers may find applications in photovoltaics or optoelectronics. It is important to study this group of material engineering and to find a new use for them. Materials from which thin films are made of will have an impact on the properties and characteristics of electronics devices in which they are be applied.Originality/value: The value of this paper is defining the optimal parameters of spin-coating technology for six polyoxadiazoles. The results allow the choosing optimal parameters of the deposition process. Spin coating is a very good method to obtain thin films which

  13. Thin Films in the Photovoltaic Industry

    International Nuclear Information System (INIS)

    In the past years, the yearly world market growth rate for Photovoltaics was an average of more than 40%, which makes it one of the fastest growing industries at present. Business analysts predict the market volume to increase to 40 billion euros in 2010 and expect rising profit margins and lower prices for consumers at the same time. Today PV is still dominated by wafer based Crystalline Silicon Technology as the 'working horse' in the global market, but thin films are gaining market shares. For 2007 around 12% are expected. The current silicon shortage and high demand has kept prices higher than anticipated from the learning curve experience and has widened the windows of opportunities for thin film solar modules. Current production capacity estimates for thin films vary between 3 and 6 GW in 2010, representing a 20% market share for these technologies. Despite the higher growth rates for thin film technologies compared with the industry average, Thin Film Photovoltaic Technologies are still facing a number of challenges to maintain this growth and increase market shares. The four main topics which were discussed during the workshop were: Potential for cost reduction; Standardization; Recycling; Performance over the lifetime.

  14. Ion beam-based characterization of multicomponent oxide thin films and thin film layered structures

    International Nuclear Information System (INIS)

    Fabrication of thin film layered structures of multi-component materials such as high temperature superconductors, ferroelectric and electro-optic materials, and alloy semiconductors, and the development of hybrid materials requires understanding of film growth and interface properties. For High Temperature Superconductors, the superconducting coherence length is extremely short (5--15 Angstrom), and fabrication of reliable devices will require control of film properties at extremely sharp interfaces; it will be necessary to verify the integrity of thin layers and layered structure devices over thicknesses comparable to the atomic layer spacing. Analytical techniques which probe the first 1--2 atomic layers are therefore necessary for in-situ characterization of relevant thin film growth processes. However, most surface-analytical techniques are sensitive to a region within 10--40 Angstrom of the surface and are physically incompatible with thin film deposition and are typically restricted to ultra high vacuum conditions. A review of ion beam-based analytical methods for the characterization of thin film and multi-layered thin film structures incorporating layers of multicomponent oxides is presented. Particular attention will be paid to the use of time-of-flight techniques based on the use of 1- 15 key ion beams which show potential for use as nondestructive, real-time, in-situ surface diagnostics for the growth of multicomponent metal and metal oxide thin films

  15. Measuring thin films by transmission spectroscopy

    International Nuclear Information System (INIS)

    Full text: The refractive index, extinction coefficient and thickness of thin dielectric films are important parameters for device manufacturers and experimenters. We have developed a method which allows these values to be determined from a single transmission spectrum of the film as deposited on a known substrate. The technique exploits the interference fringes seen in such a transmission spectrum to establish envelope functions of the turning points in the spectrum. From these envelope functions the refractive index and extinction coefficient of the film is determined at each turning point. Consequently we can determine the film's thickness with a single measurement step. Copyright (2005) Australian Institute of Physics

  16. Synthesis of long YBa2CU3O7 thin film strip conductors and investigation of their dissipative properties

    International Nuclear Information System (INIS)

    The technical modifications and the optimization of the magnetron based sputtering procedure for the production of large area YBaCuO layers is described; LaAlO3, SrTiO3 and CeO2 buffered sapphire substrates were tested. First applicability studies using 200 nm thick layers (surface roughness about 5 nm) included flux transformers, Josephson contacts and nanobridges with flux flow behavior. Resistive measurements on thin film strip lines (phase transformation and U-I characteristics) could be explained using the flux line shear model. The observed dissipative behavior is explained by partial flux flow due to inhomogeneities in the strip lines. Simulations confirmed the distribution of superconducting properties due to inhomogeneities

  17. Thermal conductivity of dielectric thin films

    International Nuclear Information System (INIS)

    A direct reading thermal comparator has been used to measure the thermal conductivity of dielectric thin film coatings. In the past, the thermal comparator has been used extensively to measure the thermal conductivity of bulk solids, liquids, and gases. The technique has been extended to thin film materials by making experimental improvements and by the application of an analytical heat flow model. Our technique also allows an estimation of the thermal resistance of the film/substrate interface which is shown to depend on the method of film deposition. The thermal conductivity of most thin films was found to be several orders of magnitude lower than that of the material in bulk form. This difference is attributed to structural disorder of materials deposited in thin film form. The experimentation to date has centered primarily on optical coating materials. These coatings, used to enhance the optical properties of components such as lenses and mirrors, are damaged by thermal loads applied in high-power laser applications. It has been widely postulated that there may be a correlation between the thermal conductivity and the damage threshold of these materials. 31 refs., 11 figs., 8 tabs

  18. Organic thin films and surfaces directions for the nineties

    CERN Document Server

    Ulman, Abraham

    1995-01-01

    Physics of Thin Films has been one of the longest running continuing series in thin film science consisting of 20 volumes since 1963. The series contains some of the highest quality studies of the properties ofvarious thin films materials and systems.In order to be able to reflect the development of todays science and to cover all modern aspects of thin films, the series, beginning with Volume 20, will move beyond the basic physics of thin films. It will address the most important aspects of both inorganic and organic thin films, in both their theoretical as well as technological aspects. Ther

  19. Crystallization of zirconia based thin films.

    Science.gov (United States)

    Stender, D; Frison, R; Conder, K; Rupp, J L M; Scherrer, B; Martynczuk, J M; Gauckler, L J; Schneider, C W; Lippert, T; Wokaun, A

    2015-07-28

    The crystallization kinetics of amorphous 3 and 8 mol% yttria stabilized zirconia (3YSZ and 8YSZ) thin films grown by pulsed laser deposition (PLD), spray pyrolysis and dc-magnetron sputtering are explored. The deposited films were heat treated up to 1000 °C ex situ and in situ in an X-ray diffractometer. A minimum temperature of 275 °C was determined at which as-deposited amorphous PLD grown 3YSZ films fully crystallize within five hours. Above 325 °C these films transform nearly instantaneously with a high degree of micro-strain when crystallized below 500 °C. In these films the t'' phase crystallizes which transforms at T > 600 °C to the t' phase upon relaxation of the micro-strain. Furthermore, the crystallization of 8YSZ thin films grown by PLD, spray pyrolysis and dc-sputtering are characterized by in situ XRD measurements. At a constant heating rate of 2.4 K min(-1) crystallization is accomplished after reaching 800 °C, while PLD grown thin films were completely crystallized already at ca. 300 °C. PMID:26119755

  20. Solid surfaces, interfaces and thin films

    CERN Document Server

    Lüth, Hans

    2015-01-01

    This book emphasises both experimental and theoretical aspects of surface, interface and thin-film physics. As in previous editions the preparation of surfaces and thin films, their atomic and morphological structure, their vibronic and electronic properties as well as fundamentals of adsorption are treated. Because of their importance in modern information technology and nanostructure research, particular emphasis is paid to electronic surface and interface states, semiconductor space charge layers and heterostructures. A special chapter of the book is devoted to collective phenomena at interfaces and in thin films such as superconductivity and magnetism. The latter topic includes the meanwhile important issues giant magnetoresistance and spin-transfer torque mechanism, both effects being of high interest in information technology. In this new edition, for the first time, the effect of spin-orbit coupling on surface states is treated. In this context the class of the recently detected topological insulators,...

  1. Method for synthesizing thin film electrodes

    Science.gov (United States)

    Boyle, Timothy J.

    2007-03-13

    A method for making a thin-film electrode, either an anode or a cathode, by preparing a precursor solution using an alkoxide reactant, depositing multiple thin film layers with each layer approximately 500 1000 .ANG. in thickness, and heating the layers to above 600.degree. C. to achieve a material with electrochemical properties suitable for use in a thin film battery. The preparation of the anode precursor solution uses Sn(OCH.sub.2C(CH.sub.3).sub.3).sub.2 dissolved in a solvent in the presence of HO.sub.2CCH.sub.3 and the cathode precursor solution is formed by dissolving a mixture of (Li(OCH.sub.2C(CH.sub.3).sub.3)).sub.8 and Co(O.sub.2CCH.sub.3).H.sub.2O in at least one polar solvent.

  2. Thin Film Photovoltaic/Thermal Solar Panels

    Institute of Scientific and Technical Information of China (English)

    David JOHNSTON

    2008-01-01

    A solar panel is described.in which thin films of semiconductor are deposited onto a metal substrate.The semiconductor-metal combination forms a thin film photovoltaic cell,and also acts as a reflector,absorber tandem, which acts as a solar selective surface,thus enhancing the solar thermal performance of the collector plate.The use of thin films reduces the distance heat is required to flow from the absorbing surface to the metal plate and heat exchange conduits.Computer modelling demonstrated that,by suitable choice of materials,photovohaic efficiency call be maintained,with thermal performance slishtly reduced,compared to that for thermal-only panels.By grading the absorber layer-to reduce the band gap in the lower region-the thermal performance can be improved,approaching that for a thermal-only solar panel.

  3. Thin-film solar cells. Duennschichtsolarzellen

    Energy Technology Data Exchange (ETDEWEB)

    Bloss, W.H.; Pfisterer, F.; Schock, H.W. (Stuttgart Univ. (Germany, F.R.). Inst. fuer Physikalische Elektronik)

    1990-01-01

    The authors present the state of the art in research and development, technology, production and marketing, and of the prospects of thin-film solar cells. Thin-film solar cells most used at present are based on amorphous silicon and on the compound semiconductors CuInSe{sub 2} and CdTe. Efficiencies in excess 12% have been achieved (14.1% with CuInSe{sub 2}). Stability is the main problem with amorphous silicon. Thin-film solar cells made from compound semiconductors do not have this problem, though their cost-effective series production needs to be shown still. The development potential of the three types mentioned will be ca. 30% in terms of efficiency: in terms of production cost, it is estimated with some certainty to be able to reach the baseline of 1 DM/Watt peak output (W{sub p}). (orig.).

  4. Multifractal characteristics of titanium nitride thin films

    Directory of Open Access Journals (Sweden)

    Ţălu Ştefan

    2015-09-01

    Full Text Available The study presents a multi-scale microstructural characterization of three-dimensional (3-D micro-textured surface of titanium nitride (TiN thin films prepared by reactive DC magnetron sputtering in correlation with substrate temperature variation. Topographical characterization of the surfaces, obtained by atomic force microscopy (AFM analysis, was realized by an innovative multifractal method which may be applied for AFM data. The surface micromorphology demonstrates that the multifractal geometry of TiN thin films can be characterized at nanometer scale by the generalized dimensions Dq and the singularity spectrum f(α. Furthermore, to improve the 3-D surface characterization according with ISO 25178-2:2012, the most relevant 3-D surface roughness parameters were calculated. To quantify the 3-D nanostructure surface of TiN thin films a multifractal approach was developed and validated, which can be used for the characterization of topographical changes due to the substrate temperature variation.

  5. Nanostructured thin films and coatings mechanical properties

    CERN Document Server

    2010-01-01

    The first volume in "The Handbook of Nanostructured Thin Films and Coatings" set, this book concentrates on the mechanical properties, such as hardness, toughness, and adhesion, of thin films and coatings. It discusses processing, properties, and performance and provides a detailed analysis of theories and size effects. The book presents the fundamentals of hard and superhard nanocomposites and heterostructures, assesses fracture toughness and interfacial adhesion strength of thin films and hard nanocomposite coatings, and covers the processing and mechanical properties of hybrid sol-gel-derived nanocomposite coatings. It also uses nanomechanics to optimize coatings for cutting tools and explores various other coatings, such as diamond, metal-containing amorphous carbon nanostructured, and transition metal nitride-based nanolayered multilayer coatings.

  6. Domains in Ferroic Crystals and Thin Films

    CERN Document Server

    Tagantsev, Alexander K; Fousek, Jan

    2010-01-01

    Domains in Ferroic Crystals and Thin Films presents experimental findings and theoretical understanding of ferroic (non-magnetic) domains developed during the past 60 years. It addresses the situation by looking specifically at bulk crystals and thin films, with a particular focus on recently-developed microelectronic applications and methods for observation of domains with techniques such as scanning force microscopy, polarized light microscopy, scanning optical microscopy, electron microscopy, and surface decorating techniques. Domains in Ferroic Crystals and Thin Films covers a large area of material properties and effects connected with static and dynamic properties of domains, which are extremely relevant to materials referred to as ferroics. In most solid state physics books, one large group of ferroics is customarily covered: those in which magnetic properties play a dominant role. Numerous books are specifically devoted to magnetic ferroics and cover a wide spectrum of magnetic domain phenomena. In co...

  7. Vibration welding system with thin film sensor

    Science.gov (United States)

    Cai, Wayne W; Abell, Jeffrey A; Li, Xiaochun; Choi, Hongseok; Zhao, Jingzhou

    2014-03-18

    A vibration welding system includes an anvil, a welding horn, a thin film sensor, and a process controller. The anvil and horn include working surfaces that contact a work piece during the welding process. The sensor measures a control value at the working surface. The measured control value is transmitted to the controller, which controls the system in part using the measured control value. The thin film sensor may include a plurality of thermopiles and thermocouples which collectively measure temperature and heat flux at the working surface. A method includes providing a welder device with a slot adjacent to a working surface of the welder device, inserting the thin film sensor into the slot, and using the sensor to measure a control value at the working surface. A process controller then controls the vibration welding system in part using the measured control value.

  8. Magnetically actuated peel test for thin films

    International Nuclear Information System (INIS)

    Delamination along thin film interfaces is a prevalent failure mechanism in microelectronic, photonic, microelectromechanical systems, and other engineering applications. Current interfacial fracture test techniques specific to thin films are limited by either sophisticated mechanical fixturing, physical contact near the crack tip, or complicated stress fields. Moreover, these techniques are generally not suitable for investigating fatigue crack propagation under cyclical loading. Thus, a fixtureless and noncontact experimental test technique with potential for fatigue loading is proposed and implemented to study interfacial fracture toughness for thin film systems. The proposed test incorporates permanent magnets surface mounted onto micro-fabricated released thin film structures. An applied external magnetic field induces noncontact loading to initiate delamination along the interface between the thin film and underlying substrate. Characterization of the critical peel force and peel angle is accomplished through in situ deflection measurements, from which the fracture toughness can be inferred. The test method was used to obtain interfacial fracture strength of 0.8-1.9 J/m2 for 1.5-1.7 μm electroplated copper on natively oxidized silicon substrates. - Highlights: ► Non-contact magnetic actuation test for interfacial fracture characterization. ► Applied load is determined through voltage applied to the driving electromagnet. ► Displacement and delamination propagation is measured using an optical profiler. ► Critical peel force and peel angle is measured for electroplated Cu thin-film on Si. ► The measured interfacial fracture energy of Cu/Si interface is 0.8-1.9 J/m2.

  9. Reel-to-reel continuous simultaneous double-sided deposition of highly textured CeO2 templates for YBa2Cu3O7-δ coated conductors

    International Nuclear Information System (INIS)

    A reel-to-reel system which allows simultaneous two-sided deposition of epitaxial CeO2 buffer layers on long length biaxially textured Ni-5 at.%W tape with direct current (dc) reactive magnetron sputtering is described. Deposition is accomplished through two opposite symmetrical sputtering guns with a radiation heater. Meter-long double-sided epitaxial CeO2 buffer layers have been produced for the first time on textured metal substrates in a run using a reel-to-reel process with a speed of about 1.2 m h-1. The CeO2 films were characterized by means of x-ray diffraction (XRD) and atomic force microscopy (AFM). The samples exhibited good epitaxial growth with the c-axis perpendicular to the substrate surface for both sides. Full width at half maximum (FWHM) values of the out-of-plane and in-plane orientation for both sides were 3.20 and 3.10, 5.30 and 5.10, respectively. AFM observations revealed a smooth, dense and crack-free surface morphology. In addition, x-ray scans have been performed as a function of length to determine the crystallographic consistency of the epitaxial CeO2 over the length. Subsequently anyttria-stabilized zirconia (YSZ) barrier and CeO2 cap layers were deposited to complete the CeO2/YSZ/CeO2 structure via the same process. Epitaxial YBa2Cu3O7-δ (YBCO) films grown by dc sputtering on the short prototype CeO2/YSZ/CeO2/NiW conductors yielded self-field critical current densities (Jc) as high as 1.3 MA cm-2 at 77 K. An Ic value of 113 A cm-1 was obtained for double-sided YBCO coated conductors

  10. Tailoring electronic structure of polyazomethines thin films

    Directory of Open Access Journals (Sweden)

    J. Weszka

    2010-09-01

    Full Text Available Purpose: The aim of this work is to show how electronic properties of polyazomethine thin films deposited by chemical vapor deposition method (CVD can be tailored by manipulating technological parameters of pristine films preparation as well as modifying them while the as-prepared films put into iodine atmosphere.Design/methodology/approach: The recent achievements in the field of designing and preparation methods to be used while preparing polymer photovoltaic solar cells or optoelectronic devices.Findings: The method used allow for pure pristine polymer thin films to be prtepared without any unintentional doping taking place during prepoaration methods. This is a method based on polycondensation process, where polymer chain developing is running directly due to chemical reaction between molecules of bifunctional monomers. The method applied to prepare thin films of polyazomethines takes advantage of monomer transporting by mreans of neutral transport agent as pure argon is.Research limitations/implications: The main disadvantage of alternately conjugated polymers seems to be quite low mobility of charge carrier that is expected to be a consequence of their backbone being built up of sp2 hybridized carbon and nitrogen atoms. Varying technological conditions towards increasing reagents mass transport to the substrate is expected to give such polyazomethine thin films organization that phenylene rin stacking can result in special π electron systems rather than linear ones as it is the case.Originality/value: Our results supply with original possibilities which can be useful in ooking for good polymer materials for optoelectronic and photovoltaic applications. These results have been gained on polyazomethine thin films but their being isoelectronic counterpart to widely used poly p-phenylene vinylene may be very convenient to develop high efficiency polymer solar cells

  11. Bilaterally Microstructured Thin Polydimethylsiloxane Film Production

    DEFF Research Database (Denmark)

    Vudayagiri, Sindhu; Yu, Liyun; Hassouneh, Suzan Sager;

    2015-01-01

    Thin PDMS films with complex microstructures are used in the manufacturing of dielectric electro active polymer (DEAP) actuators, sensors and generators, to protect the metal electrode from large strains and to assure controlled actuation. The current manufacturing process at Danfoss Polypower A...... with the existing manufacturing process. In employing the new technique, films with microstructures on both surfaces are successfully made with two different liquid silicone rubber (LSR) formulations: 1) pure XLR630 and 2) XLR630 with titanium dioxide (TiO2). The LSR films (∼70 μm) are cast on a....../S produces films with a one-sided microstructured surface only. It would be advantageous to produce a film with both surfaces microstructured, as this increases the film’s performance efficiency. The new technique introduced herein produces bilaterally microstructured film by combining an embossing method...

  12. Thin film oxygen partial pressure sensor

    Science.gov (United States)

    Wortman, J. J.; Harrison, J. W.; Honbarrier, H. L.; Yen, J.

    1972-01-01

    The development is described of a laboratory model oxygen partial pressure sensor using a sputtered zinc oxide thin film. The film is operated at about 400 C through the use of a miniature silicon bar. Because of the unique resistance versus temperature relation of the silicon bar, control of the operational temperature is achieved by controlling the resistance. A circuit for accomplishing this is described. The response of sputtered zinc oxide films of various thicknesses to oxygen, nitrogen, argon, carbon dioxide, and water vapor caused a change in the film resistance. Over a large range, film conductance varied approximately as the square root of the oxygen partial pressure. The presence of water vapor in the gas stream caused a shift in the film conductance at a given oxygen partial pressure. A theoretical model is presented to explain the characteristic features of the zinc oxide response to oxygen.

  13. Solid-state thin-film supercapacitor with ruthenium oxide and solid electrolyte thin films

    Science.gov (United States)

    Yoon, Y. S.; Cho, W. I.; Lim, J. H.; Choi, D. J.

    Direct current reactive sputtering deposition of ruthenium oxide thin films (bottom and top electrodes) at 400°C are performed to produce a solid-state thin-film supercapacitor (TFSC). The supercapacitor has a cell structure of RuO 2/Li 2.94PO 2.37N 0.75 (Lipon)/RuO 2/Pt. Radio frequency, reactive sputtering deposition of an Li 2.94PO 2.37N 0.75 electrolyte film is performed on the bottom RuO 2 film at room temperature to separate the bottom and top RuO 2 electrodes electrically. The stoichiometry of the RuO 2 thin film is investigated by Rutherford back-scattering spectrometry (RBS). X-ray diffraction (XRD) shows that the as-deposited RuO 2 thin film is an amorphous phase. Scanning electron microscopy (SEM) measurements reveal that the RuO 2/Lipon/RuO 2 hetero-interfaces have no inter-diffusion problems. Charge-discharge measurements with constant current at room temperature clearly reveal typical supercapacitor behaviour for a RuO 2/Lipon/RuO 2/Pt cell structure. Since the electrolyte thin film has low ionic mobility, the capacity and cycle performance are inferior to those of a bulk type of supercapacitor. These results indicate that a high performance, TFSC can be fabricated by a solid electrolyte thin film with high ionic conductivity.

  14. Functional planar thin film optical waveguide lasers

    International Nuclear Information System (INIS)

    Fabrication and characterization of planar and channel waveguiding thin films with the goal to develop active and passive elements are intensively studied over the last 20 years. Large scale of materials and properties were tested (morphology, crystallinity, luminescence, waveguiding, etc.). The goal of our contribution is to give an overview of materials and fabrication processes which were used for development and construction of functional planar waveguide lasers (PWL). The compact survey of finalized PWL and their basic parameters is given. A special part is devoted to fabrication of waveguide lasers using laser technology. Applications of thin film waveguide lasers are mentioned

  15. Advances in thin-film solar cells

    CERN Document Server

    Dharmadasa, I M

    2012-01-01

    This book concentrates on the latest developments in our understanding of solid-state device physics. The material presented is mainly experimental and based on CdTe thin-film solar cells. It extends these new findings to CIGS thin-film solar cells and presents a new device design based on graded bandgap multilayer solar cells. This design has been experimentally tested using the well-researched GaAs/AlGaAs system and initial devices have shown impressive device parameters. These devices are capable of absorbing all radiation (UV, visible, and infra-red) within the solar spectrum and combines

  16. Thin Films Made Fast and Modified Fast

    International Nuclear Information System (INIS)

    Thin films are playing a more and more important role for technological applications and there are many aspects of materials surface processing and thin film production, ranging from simple heat treatments to ion implantation or laser surface treatments. These methods are often very complicated, involving many basic processes and they have to be optimized for the desired application. Nuclear methods, especially Moessbauer spectroscopy, can be successfully applied for this task and some examples will be presented for laser-beam and ion-beam based processes.

  17. Intrinsically conductive polymer thin film piezoresistors

    DEFF Research Database (Denmark)

    Lillemose, Michael; Spieser, Martin; Christiansen, N.O.;

    2008-01-01

    We report on the piezoresistive effect in the intrinsically conductive polymer, polyaniline. A process recipe for indirect patterning of thin film polyaniline has been developed. Using a specially designed chip, the polyaniline thin films have been characterised with respect to resistivity and...... strain sensitivity using two- and four-point measurement method. We have found that polyaniline has a negative gauge factor of K = -4.9, which makes it a candidate for piezoresistive read-out in polymer based MEMS-devices. (C) 2007 Elsevier B.V. All rights reserved....

  18. Electrical analysis of niobium oxide thin films

    International Nuclear Information System (INIS)

    In this work, a series of niobium oxide thin films was deposited by reactive magnetron sputtering. The total pressure of Ar/O2 was kept constant at 1 Pa, while the O2 partial pressure was varied up to 0.2 Pa. The depositions were performed in a grounded and non-intentionally heated substrate, resulting in as-deposited amorphous thin films. Raman spectroscopy confirmed the absence of crystallinity. Dielectric measurements as a function of frequency (40 Hz–110 MHz) and temperature (100 K–360 K) were performed. The dielectric constant for the film samples with thickness (d) lower than 650 nm decreases with the decrease of d. The same behaviour was observed for the conductivity. These results show a dependence of the dielectric permittivity with the thin film thickness. The electrical behaviour was also related with the oxygen partial pressure, whose increment promotes an increase of the Nb2O5 stoichiometry units. - Highlights: • Niobium oxide thin films were deposited by reactive magnetron sputtering. • XRD showed a phase change with the increase of the P(O2). • Raman showed that increasing P(O2), Nb2O5 amorphous increases. • Conductivity tends to decrease with the increase of P(O2). • Dielectric analysis indicates the inexistence of preferential grow direction

  19. Perovskite Thin Films via Atomic Layer Deposition

    KAUST Repository

    Sutherland, Brandon R.

    2014-10-30

    © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. (Graph Presented) A new method to deposit perovskite thin films that benefit from the thickness control and conformality of atomic layer deposition (ALD) is detailed. A seed layer of ALD PbS is place-exchanged with PbI2 and subsequently CH3NH3PbI3 perovskite. These films show promising optical properties, with gain coefficients of 3200 ± 830 cm-1.

  20. Dynamics of liquid films and thin jets

    Science.gov (United States)

    Zak, M.

    1979-01-01

    The theory of liquid films and thin jets as one- and two-dimensional continuums is examined. The equations of motion have led to solutions for the characteristic speeds of wave propagation for the parameters characterizing the shape. The formal analogy with a compressible fluid indicates the possibility of shock wave generation in films and jets and the formal analogy to the theory of threads and membranes leads to the discovery of some new dynamic effects. The theory is illustrated by examples.

  1. Viscous fingering in volatile thin films

    OpenAIRE

    Agam, Oded

    2008-01-01

    A thin water film on a cleaved mica substrate undergoes a first order phase transition between two values of film thickness. By inducing a finite evaporation rate of the water, the interface between the two phases develops a fingering instability similar to that observed in the Saffman-Taylor problem. We draw the connection between the two problems, and construct solutions describing the dynamics of evaporation in this system.

  2. Thin film dynamics with surfactant phase transition

    OpenAIRE

    Köpf, M. H.; Gurevich, S. V.; Friedrich, R.

    2009-01-01

    A thin liquid film covered with an insoluble surfactant in the vicinity of a first-order phase transition is discussed. Within the lubrication approximation we derive two coupled equations to describe the height profile of the film and the surfactant density. Thermodynamics of the surfactant is incorporated via a Cahn-Hilliard type free-energy functional which can be chosen to describe a transition between two stable phases of different surfactant density. Within this model, a linear stabilit...

  3. Fabrication and evaluation of green-light emitting Ta2O5:Er, Ce co-sputtered thin films

    Science.gov (United States)

    Miura, K.; Osawa, T.; Suzuki, T.; Yokota, Y.; Hanaizumi, O.

    Erbium and cerium co-doped tantalum-oxide (Ta2O5:Er, Ce) thin films were fabricated using radio-frequency co-sputtering of Ta2O5, Er2O3, and CeO2 for the first time. Enhanced green-light emission due to Er3+ that seems to be sensitized by Ce3+ was observed from the film annealed at 900 °C for 20 min. From XRD measurements of the films, the β-Ta2O5 (orthorhombic), δ-Ta2O5 (hexagonal), and (2 0 1) Ta2O5 phases seem to be very important for obtaining green PL from them. Such Ta2O5:Er, Ce co-sputtered films can be used as high-refractive-index materials of autocloned photonic crystals that can be applied to novel green-light-emitting devices, and they will also be used as multi-functional coating films that can work both as anti-reflection and down-conversion films for realizing high-efficiency silicon solar cells.

  4. Fabrication and evaluation of green-light emitting Ta2O5:Er, Ce co-sputtered thin films

    Directory of Open Access Journals (Sweden)

    K. Miura

    2015-01-01

    Full Text Available Erbium and cerium co-doped tantalum-oxide (Ta2O5:Er, Ce thin films were fabricated using radio-frequency co-sputtering of Ta2O5, Er2O3, and CeO2 for the first time. Enhanced green-light emission due to Er3+ that seems to be sensitized by Ce3+ was observed from the film annealed at 900 °C for 20 min. From XRD measurements of the films, the β-Ta2O5 (orthorhombic, δ-Ta2O5 (hexagonal, and (201 Ta2O5 phases seem to be very important for obtaining green PL from them. Such Ta2O5:Er, Ce co-sputtered films can be used as high-refractive-index materials of autocloned photonic crystals that can be applied to novel green-light-emitting devices, and they will also be used as multi-functional coating films that can work both as anti-reflection and down-conversion films for realizing high-efficiency silicon solar cells.

  5. Mechanical integrity of thin films

    International Nuclear Information System (INIS)

    Mechanical considerations starting with the initial film deposition including questions of adhesion and grading the interface are reviewed. Growth stresses, limiting thickness, stress relief, control aging, and creep are described

  6. YBCO thin films in ac and dc films

    CERN Document Server

    Shahzada, S

    2001-01-01

    We report studies on the dc magnetization of YBCO thin films in simultaneously applied dc and ac fields. The effect of the ac fields is to decrease the irreversible magnetization drastically leading to complete collapse of the hysteresis loops for relatively small ac fields (250e). The magnitude of the decrease depends on the component of the ac field parallel to the c-axis. The decrease is non-linear with ac amplitude and is explained in the framework of the critical state response of ultra thin films in perpendicular geometry. The ac fields increase the relaxation rapidly at short times while the long time response appears unaffected. (author)

  7. Biaxial Fatigue Testing of Thin Films

    International Nuclear Information System (INIS)

    A new experimental setup, which allows for testing in an equi-biaxial loading condition, has been developed and applied to investigate the fatigue behaviour of thin films. A load controlled cycling, performed at room temperature on flat specimens, reproduces the strain amplitude and mean strain in the film corresponding to a thermal cycling in a given temperature range. The setup is based on the ring-on-ring test, which has been successfully used in biaxial fracture testing of glass and ceramics, and includes an optical in-situ failure detection system. The method is validated for specimens consisting in a gold film deposited on a polymer substrate

  8. Study of iron mononitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tayal, Akhil, E-mail: mgupta@csr.res.in; Gupta, Mukul, E-mail: mgupta@csr.res.in; Phase, D. M., E-mail: mgupta@csr.res.in; Reddy, V. R., E-mail: mgupta@csr.res.in; Gupta, Ajay, E-mail: mgupta@csr.res.in [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore,-452001 (India)

    2014-04-24

    In this work we have studied the crystal structural and local ordering of iron and nitrogen in iron mononitride thin films prepared using dc magnetron sputtering at sputtering power of 100W and 500W. The films were sputtered using pure nitrogen to enhance the reactivity of nitrogen with iron. The x-ray diffraction (XRD), conversion electron Mössbauer spectroscopy (CEMS) and soft x-ray absorption spectroscopy (SXAS) studies shows that the film crystallizes in ZnS-type crystal structure.

  9. Energetic Deposition of Niobium Thin Film in Vacuum

    OpenAIRE

    Wu, Genfa

    2002-01-01

    Niobium thin films are expected to be free of solid inclusions commonly seen in solid niobium. For particle accelerators, niobium thin film has the potential to replace the solid niobium in the making of the accelerating structures. In order to understand and improve the superconducting performance of niobium thin films at cryogenic temperature, an energetic vacuum deposition system has been developed to study deposition energy effects on the properties of niobium thin films on various substr...

  10. Correlated dewetting patterns in thin polystyrene films

    International Nuclear Information System (INIS)

    We describe preliminary results of experiments and simulations concerned with the dewetting of thin polystyrene films (thickness < 7 nm) on top of silicon oxide wafers. In the experiments we scratched an initially flat film with an atomic force microscopy (AFM) tip, producing dry channels in the film. Dewetting of the films was imaged in situ using AFM and a correlated pattern of holes ('satellite holes') was observed along the rims bordering the channels. The development of this complex film rupture process was simulated and the results of experiments and simulations are in good agreement. On the basis of these results, we attempt to explain the appearance of satellite holes and their positions relative to pre-existing holes

  11. Humidity sensing characteristics of hydrotungstite thin films

    Indian Academy of Sciences (India)

    G V Kunte; S A Shivashankar; A M Umarji

    2008-11-01

    Thin films of the hydrated phase of tungsten oxide, hydrotungstite (H2WO4.H2O), have been grown on glass substrates using a dip-coating technique. The -axis oriented films have been characterized by X-ray diffraction and scanning electron microscopy. The electrical conductivity of the films is observed to vary with humidity and selectively show high sensitivity to moisture at room temperature. In order to understand the mechanism of sensing, the films were examined by X-ray diffraction at elevated temperatures and in controlled atmospheres. Based on these observations and on conductivity measurements, a novel sensing mechanism based on protonic conduction within the surface layers adsorbed onto the hydrotungstite film is proposed.

  12. Correlated dewetting patterns in thin polystyrene films

    CERN Document Server

    Neto, C; Seemann, R; Blossey, R; Becker, J; Grün, G

    2003-01-01

    We describe preliminary results of experiments and simulations concerned with the dewetting of thin polystyrene films (thickness < 7 nm) on top of silicon oxide wafers. In the experiments we scratched an initially flat film with an atomic force microscopy (AFM) tip, producing dry channels in the film. Dewetting of the films was imaged in situ using AFM and a correlated pattern of holes ('satellite holes') was observed along the rims bordering the channels. The development of this complex film rupture process was simulated and the results of experiments and simulations are in good agreement. On the basis of these results, we attempt to explain the appearance of satellite holes and their positions relative to pre-existing holes.

  13. Resistance contact thin-film resistor

    Directory of Open Access Journals (Sweden)

    Spirin V. G.

    2008-10-01

    Full Text Available The analytical model of the calculation of the contact resistance of the thin-film resistor is Offered. The Explored dependency of the contact resistance from wedge of the pickling. The Considered influence adhesive layer on warm-up stability of the resistor. They Are Received formulas of the calculation systematic and casual inaccuracy contributed by contact resistance.

  14. New techniques for producing thin boron films

    International Nuclear Information System (INIS)

    A review will be presented of methods for producing thin boron films using an electron gun. Previous papers have had the problem of spattering of the boron source during the evaporation. Methods for reducing this problem will also be presented. 12 refs., 4 figs

  15. Electrical characterization of thin film ferroelectric capacitors

    NARCIS (Netherlands)

    Tiggelman, M.P.J.; Reimann, K.; Klee, M.; Beelen, D.; Keur, W.; Schmitz, J.; Hueting, R.J.E.

    2006-01-01

    Tunable capacitors can be used to facilitate the reduction of components in wireless technologies. The tunability of the capacitors is caused by the sensitivity of the relative dielectric constant to a change in polarization with electric field. Thin film ferroelectric MIM capacitors on silicon offe

  16. Ferromagnetic resonance in very thin films

    Czech Academy of Sciences Publication Activity Database

    Cochran, J. F.; Kamberský, Vladimír

    2006-01-01

    Roč. 302, - (2006), s. 348-361. ISSN 0304-8853 Institutional research plan: CEZ:AV0Z10100521 Keywords : ferromagnetic resonance * magnetic thin films Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.212, year: 2006

  17. Flexoelectricity in barium strontium titanate thin film

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Seol Ryung; Huang, Wenbin; Yuan, Fuh-Gwo; Jiang, Xiaoning, E-mail: xjiang5@ncsu.edu [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Shu, Longlong [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Electronic Materials Research Laboratory, International Center for Dielectric Research, Xi' an Jiao Tong University, Xi' an, Shaanxi 710049 (China); Maria, Jon-Paul [Department of Material Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2014-10-06

    Flexoelectricity, the linear coupling between the strain gradient and the induced electric polarization, has been intensively studied as an alternative to piezoelectricity. Especially, it is of interest to develop flexoelectric devices on micro/nano scales due to the inherent scaling effect of flexoelectric effect. Ba{sub 0.7}Sr{sub 0.3}TiO{sub 3} thin film with a thickness of 130 nm was fabricated on a silicon wafer using a RF magnetron sputtering process. The flexoelectric coefficients of the prepared thin films were determined experimentally. It was revealed that the thin films possessed a transverse flexoelectric coefficient of 24.5 μC/m at Curie temperature (∼28 °C) and 17.44 μC/m at 41 °C. The measured flexoelectric coefficients are comparable to that of bulk BST ceramics, which are reported to be 10–100 μC/m. This result suggests that the flexoelectric thin film structures can be effectively used for micro/nano-sensing devices.

  18. US Polycrystalline Thin Film Solar Cells Program

    Science.gov (United States)

    Ullal, Harin S.; Zweibel, Kenneth; Mitchell, Richard L.

    1989-11-01

    The Polycrystalline Thin Film Solar Cells Program, part of the United States National Photovoltaic Program, performs R and D on copper indium diselenide and cadmium telluride thin films. The objective of the program is to support research to develop cells and modules that meet the U.S. Department of Energy's long-term goals by achieving high efficiencies (15 to 20 percent), low-cost ($50/m(sup 2)), and long-time reliability (30 years). The importance of work in this area is due to the fact that the polycrystalline thin-film CuInSe2 and CdTe solar cells and modules have made rapid advances. They have become the leading thin films for PV in terms of efficiency and stability. The U.S. Department of Energy has increased its funding through an initiative through the Solar Energy Research Institute in CuInSe2 and CdTe with subcontracts to start in spring 1990.

  19. US polycrystalline thin film solar cells program

    Energy Technology Data Exchange (ETDEWEB)

    Ullal, H S; Zweibel, K; Mitchell, R L [Solar Energy Research Inst., Golden, CO (USA)

    1989-11-01

    The Polycrystalline Thin Film Solar Cells Program, part of the United States National Photovoltaic Program, performs R D on copper indium diselenide and cadmium telluride thin films. The objective of the Program is to support research to develop cells and modules that meet the US Department of Energy's long-term goals by achieving high efficiencies (15%-20%), low-cost ($50/m{sup 2}), and long-time reliability (30 years). The importance of work in this area is due to the fact that the polycrystalline thin-film CuInSe{sub 2} and CdTe solar cells and modules have made rapid advances. They have become the leading thin films for PV in terms of efficiency and stability. The US Department of Energy has increased its funding through an initiative through the Solar Energy Research Institute in CuInSe{sub 2} and CdTe with subcontracts to start in Spring 1990. 23 refs., 5 figs.

  20. A ferroelectric transparent thin-film transistor

    NARCIS (Netherlands)

    Prins, MWJ; GrosseHolz, KO; Muller, G; Cillessen, JFM; Giesbers, JB; Weening, RP; Wolf, RM

    1996-01-01

    Operation is demonstrated of a field-effect transistor made of transparant oxidic thin films, showing an intrinsic memory function due to the usage of a ferroelectric insulator. The device consists of a high mobility Sb-doped n-type SnO2 semiconductor layer, PbZr0.2Ti0.8Os3 as a ferroelectric insula

  1. Microwave-enhanced thin-film deposition

    Science.gov (United States)

    Chitre, S.

    1984-01-01

    The deposition of semiconducting and insulating thin films at low temperatures using microwave technology was explored. The method of plasma formations, selection of a power source, the design of the microwave plasma cavity, the microwave circuitry, impedance matching, plasma diagnostics, the deposition chamber and the vacuum system were studied.

  2. Rechargeable Thin-film Lithium Batteries

    Science.gov (United States)

    Bates, J. B.; Gruzalski, G. R.; Dudney, N. J.; Luck, C. F.; Yu, Xiaohua

    1993-08-01

    Rechargeable thin film batteries consisting of lithium metal anodes, an amorphous inorganic electrolyte, and cathodes of lithium intercalation compounds have recently been developed. The batteries, which are typically less than 6 {mu}m thick, can be fabricated to any specified size, large or small, onto a variety of substrates including ceramics, semiconductors, and plastics. The cells that have been investigated include Li TiS{sub 2}, Li V{sub 2}O{sub 5}, and Li Li{sub x}Mn{sub 2}O{sub 4}, with open circuit voltages at full charge of about 2.5, 3.6, and 4.2, respectively. The development of these batteries would not have been possible without the discovery of a new thin film lithium electrolyte, lithium phosphorus oxynitride, that is stable in contact with metallic lithium at these potentials. Deposited by rf magnetron sputtering of Li{sub 3}PO{sub 4} in N{sub 2}, this material has a typical composition of Li{sub 2.9}PO{sub 3.3}N{sub 0.46} and a conductivity at 25{degrees}C of 2 {mu}S/cm. The maximum practical current density obtained from the thin film cells is limited to about 100 {mu}A/cm{sup 2} due to a low diffusivity of Li{sup +} ions in the cathodes. In this work, the authors present a short review of their work on rechargeable thin film lithium batteries.

  3. Thermoviscoelastic models for polyethylene thin films

    DEFF Research Database (Denmark)

    Li, Jun; Kwok, Kawai; Pellegrino, Sergio

    2016-01-01

    This paper presents a constitutive thermoviscoelastic model for thin films of linear low-density polyethylene subject to strains up to yielding. The model is based on the free volume theory of nonlinear thermoviscoelasticity, extended to orthotropic membranes. An ingredient of the present approach...

  4. Surface spin slips in thin holmium films

    Directory of Open Access Journals (Sweden)

    F. H. S. Sales

    2012-09-01

    Full Text Available We report a theoretical investigation of new spin slips phases of thin holmium (Ho films. The new phases originate from the loss of coordination of atoms in the near surface region, which affects the balance between exchange and anisotropy energies, favoring the alignment of near surface spins along the basal plane easy axis directions.

  5. Monte Carlo simulation of magnetic nanostructured thin films

    Institute of Scientific and Technical Information of China (English)

    Guan Zhi-Qiang; Yutaka Abe; Jiang Dong-Hua; Lin Hai; Yoshitake Yamazakia; Wu Chen-Xu

    2004-01-01

    @@ Using Monte Carlo simulation, we have compared the magnetic properties between nanostructured thin films and two-dimensional crystalline solids. The dependence of nanostructured properties on the interaction between particles that constitute the nanostructured thin films is also studied. The result shows that the parameters in the interaction potential have an important effect on the properties of nanostructured thin films at the transition temperatures.

  6. Microstructure and superconducting properties of YBa2Cu3O7−δ thin films incorporated with a self-assembled magnetic vertically aligned nanocomposite

    International Nuclear Information System (INIS)

    A thin layer of a vertically aligned nanocomposite (VAN) with separated phases of ferromagnetic Fe2O3 and non-magnetic CeO2, arranged as alternating nanopillars, is introduced in YBa2Cu3O7−δ (YBCO) thin films as either a cap or a buffer layer using a pulsed laser deposition method. Detailed microstructural characterization including XRD, high resolution XTEM and STEM is conducted and correlated with the superconducting properties to investigate the flux pinning properties introduced by the magnetic VAN layers. The Tc values of both doped samples are above 89 K and the Jcsf measured at 65 K increased to 150% of that of the reference YBCO prepared under the same conditions. As the measurement temperature decreases, the magnetic pinning effect increases and the field dependent Jc(H ∥ c) is further improved to more than 200% of the Jc value of the reference YBCO sample. This suggests that the Fe2O3:CeO2 VAN can provide both ordered magnetic pillars and controlled defect density. Furthermore, the magnetic pillars are very effective pinning centers especially in the high field and low temperature regime. (paper)

  7. Thin Films Characterization by Ultra Trace Metrology

    International Nuclear Information System (INIS)

    Sensitive and accurate characterization of thin films used in nanoelectronics, thinner than a few nm, represents a challenge for many conventional methods, especially when considering in-line control. With capabilities in the E10 at/cm2 (2O3 tunnel oxide deposited on a magnetic stack. On the other hand, composition analysis by TXRF, and especially the detection of minor elements into thin films, requires the use of a specific incident angle to optimize sensitivity. Under the best conditions, determination of the composition of Co -based self aligned barriers (CoWP and CoWMoPB films with Co concentration >80%) is done with a precision of 6% on P, 8% on Mo and 13% on W (standard deviation)

  8. Hematite thin films: growth and characterization

    Science.gov (United States)

    Uribe, J. D.; Osorio, J.; Barrero, C. A.; Giratá, D.; Morales, A. L.; Devia, A.; Gómez, M. E.; Ramirez, J. G.; Gancedo, J. R.

    We have grown hematite (α - Fe 2 O 3) thin films on stainless steel and (001)-silicon single-crystal substrates by RF magnetron sputtering process in argon atmosphere at substrate temperatures from 400 to 800°C. Conversion Electron Mössbauer (CEM) spectra of the sample grown on stainless steel at 400°C exhibit values for hyperfine parameter characteristic of bulk hematite phase in the weak ferromagnetic state. Also, the relative line intensity ratio suggests that the magnetization vector of the polycrystalline film is aligned preferentially parallel to the surface. The X-ray diffraction (XRD) pattern of the polycrystalline thin film grown on steel substrates also corresponds to α - Fe 2O3. The samples were also analyzed by Atomic Force Microscopy (AFM), those grown on stainless steel reveal a morphology consisting of columnar grains with random orientation, given the inhomogeneity of the substrate surface.

  9. Thin film bismuth iron oxides useful for piezoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    Zeches, Robert J.; Martin, Lane W.; Ramesh, Ramamoorthy

    2016-05-31

    The present invention provides for a composition comprising a thin film of BiFeO.sub.3 having a thickness ranging from 20 nm to 300 nm, a first electrode in contact with the BiFeO.sub.3 thin film, and a second electrode in contact with the BiFeO.sub.3 thin film; wherein the first and second electrodes are in electrical communication. The composition is free or essentially free of lead (Pb). The BFO thin film is has the piezoelectric property of changing its volume and/or shape when an electric field is applied to the BFO thin film.

  10. Thin-film cadmium telluride solar cells

    Science.gov (United States)

    Chu, T. L.

    1987-10-01

    Cadmium telluride, with a room-temperature band-gap energy of 1.5 eV, is a promising thin-film photovoltaic material. The major objective of this research has been to demonstrate thin-film CdTe heterojunction solar cells with a total area greater than 1 sq cm and photovoltaic efficiencies of 13 percent or more. Thin-film p-CdTe/CdS/SnO2:F/glass solar cells with an AM1.5 efficiency of 10.5 percent have been reported previously. This report contains results of work done on: (1) the deposition, resistivity control, and characterization of p-CdTe films by the close-spaced sublimation process; (2) the deposition of large-band-gap window materials; (3) the electrical properties of CdS/CdTe heterojunctions; (4) the formation of stable, reproducible, ohmic contacts (such as p-HgTe) to p-CdTe; and (5) the preparation and evaluation of heterojunction solar cells.

  11. Energetic deposition of thin metal films

    CERN Document Server

    Al-Busaidy, M S K

    2001-01-01

    deposited films. The primary aim of this thesis was to study the physical effect of energetic deposition metal thin films. The secondary aim is to enhance the quality of the films produced to a desired quality. Grazing incidence X-ray reflectivity (GIXR) measurements from a high-energy synchrotron radiation source were carried out to study and characterise the samples. Optical Profilers Interferometery, Atomic Force Microscope (AFM), Auger electron spectroscopy (AES), Medium energy ion spectroscopy (MEIS), and the Electron microscope studies were the other main structural characterisation tools used. AI/Fe trilayers, as well as multilayers were deposited using a Nordico planar D.C. magnetron deposition system at different voltage biases and pressures. The films were calibrated and investigated. The relation between energetic deposition variation and structural properties was intensely researched. Energetic deposition refers to the method in which the deposited species possess higher kinetic energy and impact ...

  12. Basic thin film processing for high-Tc superconductors

    International Nuclear Information System (INIS)

    Much attention has been paid for the thin films of perovskite-type oxides especially for the thin films of the high-Tc superconducting ceramics. Historically the thin films of the perovskite-type oxides have been studied as a basic research for ferroelectric materials. Thin films of BaTiO3 and PbTiO3 were tried to deposited and there ferroelectricity was evaluated. Recently this kind of perovskite thin films, including PZT (PbTiO3-PbZrO3) and PLZT [(Pb, La) (Zr, T)O3] have been studied in relation to the synthesis of thin film dielectrics, pyroelectrics, piezoelectrics, electro-optic materials, and acousto-optic materials. Thin films of BPB (BaPbO3- BaBiO3) were studied as oxide superconductors. At present the thin films of the rare-earth high-Tc superconductors of LSC (La1-xSrxCuO4) and YBC (YBa2Cu3O7-δ) have been successfully synthesized owing to the previous studies on the ferroelectric thin films of the perovskite- type oxides. Similar to the rare-earth high-Tc superconductors thin films of the rare-earth-free high-Tc superconductors of BSCC (Bi-Sr-Ca-Cu-O)9 and TBCC (Tl- Ba-Ca-Cu-O)10 system have been synthesized. In this section the basic processes for the fabrication of the high- Tc perovskite superconducting thin films are described

  13. Thin Films for Coating Nanomaterials

    Institute of Scientific and Technical Information of China (English)

    S.M.Mukhopadhyay; P.Joshi; R.V.Pulikollu

    2005-01-01

    For nano-structured solids (those with one or more dimensions in the 1-100 nm range), attempts of surface modification can pose significant and new challenges. In traditional materials, the surface coating could be several hundreds nanometers in thickness, or even microns and millimeters. In a nano-structured material, such as particle or nanofibers, the coating thickness has to be substantially smaller than the bulk dimensions (100 nm or less), yet be durable and effective. In this paper, some aspects of effective nanometer scale coatings have been discussed. These films have been deposited by a non-line of sight (plasma)techniques; and therefore, they are capable of modifying nanofibers, near net shape cellular foams, and other high porosity materials. Two types of coatings will be focused upon: (a) those that make the surface inert and (b) those designed to enhance surface reactivity and bonding. The former has been achieved by forming 1-2 nm layer of -CF2- (and/or CF3) groups on the surface, and the latter by creating a nanolayer of SiO2-type compound. Nucleation and growth studies of the plasma-generated film indicate that they start forming as 2-3 nm high islands that grow laterally, and eventually completely cover the surface with 2-3nm film. Contact angle measurements indicate that these nano-coatings are fully functional even before they have achieved complete coverage of 2-3 nm. They should therefore be applicable to nano-structural solids.This is corroborated by application of these films on vapor grown nanofibers of carbon, and on graphitic foams. Coated and uncoated materials are infiltrated with epoxy matrix to form composites and their microstructure, as well as mechanical behaviors are compared. The results show that the nano-oxide coating can significantly enhance bond formation between carbon and organic phases, thereby enhancing wettability,dispersion, and composite behavior. The fluorocarbon coating, as expected, reduces bond formation, and

  14. Optical thin films and coatings from materials to applications

    CERN Document Server

    Flory, Francois

    2013-01-01

    Optical coatings, including mirrors, anti-reflection coatings, beam splitters, and filters, are an integral part of most modern optical systems. This book provides an overview of thin film materials, the properties, design and manufacture of optical coatings and their use across a variety of application areas.$bOptical coatings, including mirrors, anti-reflection coatings, beam splitters, and filters, are an integral part of most modern optical systems. Optical thin films and coatings provides an overview of thin film materials, the properties, design and manufacture of optical coatings and their use across a variety of application areas. Part one explores the design and manufacture of optical coatings. Part two highlights unconventional features of optical thin films including scattering properties of random structures in thin films, optical properties of thin film materials at short wavelengths, thermal properties and colour effects. Part three focusses on novel materials for optical thin films and coatings...

  15. PLD-grown thin film saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Tellkamp, Friedjof

    2012-11-01

    The subject of this thesis is the preparation and characterization of thin films made of oxidic dielectrics which may find their application as saturable absorber in passively Q-switched lasers. The solely process applied for fabrication of the thin films was the pulsed laser deposition (PLD) which stands out against other processes by its flexibility considering the composition of the systems to be investigated. Within the scope of this thesis the applied saturable absorbers can be divided into two fundamentally different kinds of functional principles: On the one hand, saturable absorption can be achieved by ions embedded in a host medium. Most commonly applied bulk crystals are certain garnets like YAG (Y{sub 3}Al{sub 5}O{sub 12}) or the spinel forsterite (Mg{sub 2}SiO{sub 4}), in each case with chromium as dopant. Either of these media was investigated in terms of their behavior as PLD-grown saturable absorber. Moreover, experiments with Mg{sub 2}GeO{sub 4}, Ca{sub 2}GeO{sub 4}, Sc{sub 2}O{sub 3}, and further garnets like YSAG or GSGG took place. The absorption coefficients of the grown films of Cr{sup 4+}:YAG were determined by spectroscopic investigations to be one to two orders of magnitude higher compared to commercially available saturable absorbers. For the first time, passive Q-switching of a Nd:YAG laser at 1064 nm with Cr{sup 4+}:YAG thin films could be realized as well as with Cr:Sc{sub 2}O{sub 3} thin films. On the other hand, the desirable effect of saturable absorption can also be generated by quantum well structures. For this purpose, several layer system like YAG/LuAG, Cu{sub 2}O/MgO, and ZnO/corumdum were investigated. It turned out that layer systems with indium oxide (In{sub 2}O{sub 3}) did not only grew in an excellent way but also showed up a behavior regarding their photo luminescence which cannot be explained by classical considerations. The observed luminescence at roughly 3 eV (410 nm) was assumed to be of excitonic nature and its

  16. Thin film cadmium telluride solar cells

    Science.gov (United States)

    Chu, T. L.; Chu, Shirley S.; Ang, S. T.; Mantravadi, M. K.

    1987-08-01

    Thin-film p-CdTe/CdS/SnO2:F/glass solar cells of the inverted configuration were prepared by the deposition of p-type CdTe films onto CdS/SnO2:F/glass substrates using CVD or close-spaced sublimation (CSS) techniques based on the procedures of Chu et al. (1983) and Nicholl (1963), respectively. The deposition rates of p-CdTe films deposited by CSS were higher than those deposited by the CVD technique (4-5 min were sufficient), and the efficiencies higher than 10 percent were obtained. However, the resistivity of films prepared by CSS was not as readily controlled as that of the CVD films. The simplest technique to reduce the resistivity of the CSS p-CdTe films was to incorporate a dopant, such as As or Sb, into the reaction mixture during the preparation of the source material. The films with resistivities in the range of 500-1000 ohm cm were deposited in this manner.

  17. Non-local thin films in Casimir force calculations

    OpenAIRE

    Esquivel, R.; Svetovoy, V.

    2005-01-01

    he Casimir force is calculated between plates with thin metallic coating. Thin films are described with spatially dispersive (nonlocal) dielectric functions. For thin films the nonlocal effects are more relevant than for half-spaces. However, it is shown that even for film thickness smaller than the mean free path for electrons, the difference between local and nonlocal calculations of the Casimir force is of the order of a few tenths of a percent. Thus the local description of thin metallic ...

  18. Nitrogen doped zinc oxide thin film

    Energy Technology Data Exchange (ETDEWEB)

    Li, Sonny X.

    2003-12-15

    To summarize, polycrystalline ZnO thin films were grown by reactive sputtering. Nitrogen was introduced into the films by reactive sputtering in an NO{sub 2} plasma or by N{sup +} implantation. All ZnO films grown show n-type conductivity. In unintentionally doped ZnO films, the n-type conductivities are attributed to Zn{sub i}, a native shallow donor. In NO{sub 2}-grown ZnO films, the n-type conductivity is attributed to (N{sub 2}){sub O}, a shallow double donor. In NO{sub 2}-grown ZnO films, 0.3 atomic % nitrogen was found to exist in the form of N{sub 2}O and N{sub 2}. Upon annealing, N{sub 2}O decomposes into N{sub 2} and O{sub 2}. In furnace-annealed samples N{sub 2} redistributes diffusively and forms gaseous N{sub 2} bubbles in the films. Unintentionally doped ZnO films were grown at different oxygen partial pressures. Zni was found to form even at oxygen-rich condition and led to n-type conductivity. N{sup +} implantation into unintentionally doped ZnO film deteriorates the crystallinity and optical properties and leads to higher electron concentration. The free electrons in the implanted films are attributed to the defects introduced by implantation and formation of (N{sub 2}){sub O} and Zni. Although today there is still no reliable means to produce good quality, stable p-type ZnO material, ZnO remains an attractive material with potential for high performance short wavelength optoelectronic devices. One may argue that gallium nitride was in a similar situation a decade ago. Although we did not obtain any p-type conductivity, we hope our research will provide a valuable reference to the literature.

  19. PST thin films for electrocaloric coolers

    International Nuclear Information System (INIS)

    Relaxor behaviour in a thin film of partially ordered PbSc0.5Ta0.5O3 (PST) was confirmed via slim P-E loops and the frequency dependence of the temperature at which the dielectric constant is maximum. Indirect measurements of the electrocaloric effect suggest that removing a field of 774 kV cm-1 yields a temperature change of -3.5 deg. C to -6.9 deg. C over a broad range of operating temperatures near room temperature (1-127 deg. C), with a correspondingly large refrigerant capacity of 662 J kg-1. In addition to low electrical hysteresis, there is negligible thermal hysteresis. PST thin films are therefore promising for EC cooling near room temperature.

  20. Generalized Ellipsometry on Ferromagnetic Sculptured Thin Films.

    Science.gov (United States)

    Schmidt, Daniel; Hofmann, Tino; Mok, Kah; Schmidt, Heidemarie; Skomski, Ralf; Schubert, Eva; Schubert, Mathias

    2011-03-01

    We present and discuss generalized ellipsometry and generalized vector-magneto-optic ellipsometry investigations on cobalt nanostructured thin films with slanted, highly-spatially coherent, columnar arrangement. The samples were prepared by glancing angle deposition. The thin films are highly transparent and reveal strong form-induced birefringence. We observe giant Kerr rotation in the visible spectral region, tunable by choice of the nanostructure geometry. Spatial magnetization orientation hysteresis and magnetization magnitude hysteresis properties are studied using a 3-dimensional Helmholtz coil arrangement allowing for arbitrary magnetic field direction at the sample position for field strengths up to 0.4 Tesla. Analysis of data obtained within this novel vector-magneto-optic setup reveals magnetization anisotropy of the Co slanted nanocolumns supported by mean-field theory modeling.

  1. Multiferroic oxide thin films and heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chengliang, E-mail: cllu@mail.hust.edu.cn, E-mail: Tao.Wu@kaust.edu.sa [School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Hu, Weijin; Wu, Tom, E-mail: cllu@mail.hust.edu.cn, E-mail: Tao.Wu@kaust.edu.sa [Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Tian, Yufeng [School of Physics, Shandong University, Jinan 250100 (China)

    2015-06-15

    Multiferroic materials promise a tantalizing perspective of novel applications in next-generation electronic, memory, and energy harvesting technologies, and at the same time they also represent a grand scientific challenge on understanding complex solid state systems with strong correlations between multiple degrees of freedom. In this review, we highlight the opportunities and obstacles in growing multiferroic thin films with chemical and structural integrity and integrating them in functional devices. Besides the magnetoelectric effect, multiferroics exhibit excellent resistant switching and photovoltaic properties, and there are plenty opportunities for them to integrate with other ferromagnetic and superconducting materials. The challenges include, but not limited, defect-related leakage in thin films, weak magnetism, and poor control on interface coupling. Although our focuses are Bi-based perovskites and rare earth manganites, the insights are also applicable to other multiferroic materials. We will also review some examples of multiferroic applications in spintronics, memory, and photovoltaic devices.

  2. Multiferroic oxide thin films and heterostructures

    KAUST Repository

    Lu, Chengliang

    2015-05-26

    Multiferroic materials promise a tantalizing perspective of novel applications in next-generation electronic, memory, and energy harvesting technologies, and at the same time they also represent a grand scientific challenge on understanding complex solid state systems with strong correlations between multiple degrees of freedom. In this review, we highlight the opportunities and obstacles in growing multiferroic thin films with chemical and structural integrity and integrating them in functional devices. Besides the magnetoelectric effect, multiferroics exhibit excellent resistant switching and photovoltaic properties, and there are plenty opportunities for them to integrate with other ferromagnetic and superconducting materials. The challenges include, but not limited, defect-related leakage in thin films, weak magnetism, and poor control on interface coupling. Although our focuses are Bi-based perovskites and rare earth manganites, the insights are also applicable to other multiferroic materials. We will also review some examples of multiferroic applications in spintronics, memory, and photovoltaic devices.

  3. Origin of enhanced photocatalytic activity of F-doped CeO2 nanocubes

    Science.gov (United States)

    Miao, Hui; Huang, Gui-Fang; Liu, Jin-Hua; Zhou, Bing-Xin; Pan, Anlian; Huang, Wei-Qing; Huang, Guo-Fang

    2016-05-01

    CeO2 nanoparticles are synthesized using a low-temperature solution combustion method and subsequent heat treatment in air. It is found that F-doping leads to smaller particle size and the formation of CeO2 nanocubes with higher percentage of reactive facets exposed. The band gap is estimated to be 3.16 eV and 2.88 eV, for pure CeO2 and fluorine doped CeO2 (F-doped CeO2) nanocubes, respectively. The synthesized F-doped CeO2 nanocubes exhibit much higher photocatalytic activities than commercial TiO2 and spherical CeO2 for the degradation of MB dye under UV and visible light irradiation. The apparent reaction rate constant k of MB decomposition over the optimized F-doped CeO2 nanocubes is 9.5 times higher than that of pure CeO2 and 2.2 times higher than that of commercial TiO2. The enhanced photocatalytic activity of F-doped CeO2 nanocubes originates from the fact that F-doping induces the small size, the highly reactive facets exposed, the intense absorption in the UV-vis range and the narrowing of the band gap. This research provides some new insights for the synthesis of the doping of the foreign atoms into photocatalyst with controlled morphology and enhanced photocatalytic activity.

  4. Electrical characterization of thin film ferroelectric capacitors

    OpenAIRE

    Tiggelman, M.P.J.; Reimann, K.; Klee, M.; Beelen, D; Keur, W.; J. Schmitz; Hueting, R.J.E.

    2006-01-01

    Tunable capacitors can be used to facilitate the reduction of components in wireless technologies. The tunability of the capacitors is caused by the sensitivity of the relative dielectric constant to a change in polarization with electric field. Thin film ferroelectric MIM capacitors on silicon offer a re-use of electronic circuitry, low tuning voltages, a high capacitance density, a low cost, a presence of bulk acoustic wave resonance(s) and decoupling functionality. The basic operation and ...

  5. Quantized Nanocrystalline CdTe Thin Films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nanocrystalline CdTe thin films were prepared by asymmetric rectangular pulse electrodeposition in organic solution at 110°C. STM image shows a porous network morphology constructed by interconnected spherical CdTe crystallites with a mean diameter of 4.2 nm. A pronounced size quantization was indicated in the action and absorption spectra. Potentials dependence dual conductive behavior was revealed in the photocurrent-potential (I-V) curves.

  6. Amperometric Noise at Thin Film Band Electrodes

    DEFF Research Database (Denmark)

    Larsen, Simon T.; Heien, Michael L.; Taboryski, Rafael

    2012-01-01

    Background current noise is often a significant limitation when using constant-potential amperometry for biosensor application such as amperometric recordings of transmitter release from single cells through exocytosis. In this paper, we fabricated thin-film electrodes of gold and conductive...... presented here can be used for choosing an electrode material and dimensions and when designing chip-based devices for low-noise current measurements....

  7. Ferromagnetic Liquid Thin Films Under Applied Field

    OpenAIRE

    Banerjee, S.; Widom, M.

    1999-01-01

    Theoretical calculations, computer simulations and experiments indicate the possible existence of a ferromagnetic liquid state, although definitive experimental evidence is lacking. Should such a state exist, demagnetization effects would force a nontrivial magnetization texture. Since liquid droplets are deformable, the droplet shape is coupled with the magnetization texture. In a thin-film geometry in zero applied field, the droplet has a circular shape and a rotating magnetization texture ...

  8. Electrochemical Analysis of Conducting Polymer Thin Films

    OpenAIRE

    Bin Wang; Vyas, Ritesh N.

    2010-01-01

    Polyelectrolyte multilayers built via the layer-by-layer (LbL) method has been one of the most promising systems in the field of materials science. Layered structures can be constructed by the adsorption of various polyelectrolyte species onto the surface of a solid or liquid material by means of electrostatic interaction. The thickness of the adsorbed layers can be tuned precisely in the nanometer range. Stable, semiconducting thin films are interesting research subjects. We use a conducting...

  9. Thin-film silicon solar cell technology

    Energy Technology Data Exchange (ETDEWEB)

    Shah, A.V.; Meier, J.; Kroll, U.; Droz, C.; Bailat, J. [University of Neuchatel (Switzerland). Inst. of Microtechnology; Schade, H. [RWE Schott Solar GmbH, Putzbrunn (Germany); Vanecek, M. [Academy of Sciences, Prague (Czech Republic). Inst. of Physics; Vallat Sauvain, E.; Wyrsch, N. [University of Neuchatel (Switzerland). Inst. of Microtechnology; Unaxis SPTec S A, Neuchatel (Switzerland)

    2004-07-01

    This paper describes the use, within p-i-n- and n-i-p-type solar cells, of hydrogenated amorphous silicon (a-Si:H) and hydrogenated microcrystalline silicon ({mu}c-Si:H) thin films (layers), both deposited at low temperatures (200{sup o}C) by plasma-assisted chemical vapour deposition (PECVD), from a mixture of silane and hydrogen. Optical and electrical properties of the i-layers are described. These properties are linked to the microstructure and hence to the i-layer deposition rate, that in turn, affects throughput in production. The importance of contact and reflection layers in achieving low electrical and optical losses is explained, particularly for the superstrate case. Especially the required properties for the transparent conductive oxide (TCO) need to be well balanced in order to provide, at the same time, for high electrical conductivity (preferably by high electron mobility), low optical absorption and surface texture (for low optical losses and pronounced light trapping). Single-junction amorphous and microcrystalline p-i-n-type solar cells, as fabricated so far, are compared in their key parameters (J{sub sc},FF,V{sub oc}) with the [theoretical] limiting values. Tandem and multijunction cells are introduced; the {mu}c-Si: H/a-Si: H or [micromorph] tandem solar cell concept is explained in detail, and recent results obtained here are listed and commented. Factors governing the mass-production of thin-film silicon modules are determined both by inherent technical reasons, described in detail, and by economic considerations. The cumulative effect of these factors results in distinct efficiency reductions from values of record laboratory cells to statistical averages of production modules. Finally, applications of thin-film silicon PV modules, especially in building-integrated PV (BIPV) are shown. In this context, the energy yields of thin-film silicon modules emerge as a valuable gauge for module performance, and compare very favourably with those of

  10. Thin film sensors for measuring small forces

    OpenAIRE

    F. Schmaljohann; Hagedorn, D.; LÖffler, F.

    2015-01-01

    Especially in the case of measuring small forces, the use of conventional foil strain gauges is limited. The measurement uncertainty rises by force shunts and is due to the polymer foils used, as they are susceptible to moisture. Strain gauges in thin film technology present a potential solution to overcome these effects because of their direct and atomic contact with the measuring body, omitting an adhesive layer and the polymer foil. For force measurements up to 1 N, a...

  11. Structures for dense, crack free thin films

    Science.gov (United States)

    Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2011-03-08

    The process described herein provides a simple and cost effective method for making crack free, high density thin ceramic film. The steps involve depositing a layer of a ceramic material on a porous or dense substrate. The deposited layer is compacted and then the resultant laminate is sintered to achieve a higher density than would have been possible without the pre-firing compaction step.

  12. Recent developments in thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Dhere, N.G. (Inst. Militar de Engenharia, Rio de Janeiro, RJ (Brazil))

    1990-12-15

    In recent years, remarkable progress has been made in improving the photovoltaic (PV) conversion efficiencies of thin film solar cells. The best active-area efficiencies (air mass 1.5) of thin film solar cells reported are as follows: polycrystalline CuInSe{sub 2}, 14.1%; CuIn(Ga)Se{sub 2}, 12.9%; CdTe, 12.3%, total area; single-junction hydrogenated amorphous silicon (a-Si:H), 12.0%; multiple-junction a-Si:H, 13.3%; cleaved epitaxial GaAs-Ga{sub 1-x}Al{sub x}As, 21.5%, total area. Laboratory methods for preparing small thin film solar cells are evaporation, closed-space sublimation, closed-space vapor transport, vapor phase epitaxy and metallo-organic chemical vapor deposition, while economic large-area deposition techniques such as sputtering, glow discharge reduction, electrodeposition, spraying and screen printing are being used for module fabrication. The following aperture-area efficiencies have been measured, at the Solar Energy Research Inst., for thin film modules: a-Si:H, 9.8%, 933 cm{sup 2}; CuIn(Ga)Se{sub 2}, 11.1%, 938 cm{sup 2}; CdTe, 7.3%, 838 cm{sup 2}. The instability issue of a-Si:H continues to be a high priority area. It is necessary to improve the open-circuit voltage of CuIn(Ga)Se{sub 2} cells, which do not seem to exhibit any intrinsic degradation mechanisms. With continued progress and increased production, PV modules are likely to become competitive for medium-scale power requirements in the mid-1990s. (orig.).

  13. Surface morphology of thin films polyoxadiazoles

    OpenAIRE

    J. Weszka; M.M. Szindler; M. Chwastek-Ogierman; M. Bruma; P. Jarka; Tomiczek, B.

    2011-01-01

    urpose: The purpose of this paper was to analyse the surface morphology of thin films polyoxadiazoles. Design/methodology/approach: SSix different polymers which belong to the group of polyoxadiazoles were dissolved in the solvent NMP. Each of these polymer was deposited on a glass substrate and a spin coating method was applied with a spin speed of 1000, 2000 and 3000 rev/min. Changes in surface topography and roughness were observed. An atomic force microscope AFM Park System has been used....

  14. Amorphous silicon for thin-film transistors

    OpenAIRE

    Schropp, Rudolf Emmanuel Isidore

    1987-01-01

    Hydrogenated amorphous silicon (a-Si:H) has considerable potential as a semiconducting material for large-area photoelectric and photovoltaic applications. Moreover, a-Si:H thin-film transistors (TFT’s) are very well suited as switching devices in addressable liquid crystal display panels and addressable image sensor arrays, due to a new technology of low-cost, Iow-temperature processing overlarge areas. ... Zie: Abstract

  15. Fluxoid dynamics in superconducting thin film rings

    OpenAIRE

    Kirtley, J. R.; Tsuei, C. C.; Kogan, V. G.; Clem, J. R.; Raffy, H.; Li, Z. Z.

    2003-01-01

    We have measured the dynamics of individual magnetic fluxoids entering and leaving photolithographically patterned thin film rings of the underdoped high-temperature superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\\delta}$, using a variable sample temperature scanning SQUID microscope. These results can be qualitatively described using a model in which the fluxoid number changes by thermally activated nucleation of a Pearl vortex in, and transport of the Pearl vortex across, the ring wall.

  16. Thin-film silicon solar cell technology

    Czech Academy of Sciences Publication Activity Database

    Shah, A. V.; Schade, H.; Vaněček, Milan; Meier, J.; Vallat-Sauvain, E.; Wyrsch, N.; Kroll, U.; Droz, C.; Bailat, J.

    2004-01-01

    Roč. 12, - (2004), s. 113-142. ISSN 1062-7995 R&D Projects: GA MŽP SN/320/11/03 Institutional research plan: CEZ:AV0Z1010914 Keywords : thin-film silicon modules * hydrogen erated amorphous silicon(a-Si:H) * hydrogen erated microcrystalline (ćc-Si:H) * transparent conductive oxydes(TCOs) * building-integrated photovoltaics(BIPV) Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.196, year: 2004

  17. Casimir force between atomically thin gold films

    OpenAIRE

    Boström, Mathias; Persson, Clas; Sernelius, Bo E.

    2013-01-01

    We have used density functional theory to calculate the anisotropic dielectric functions for ultrathin gold sheets (composed of 1, 3, 6, and 15 atomic layers). Such films are important components in nano-electromechanical systems. When using correct dielectric functions rather than bulk gold dielectric functions we predict an enhanced attractive Casimir-Lifshitz force (at most around 20%) between two atomically thin gold sheets. For thicker sheets the dielectric properties and the correspondi...

  18. The carbonization of thin polyaniline films

    Czech Academy of Sciences Publication Activity Database

    Morávková, Zuzana; Trchová, Miroslava; Exnerová, Milena; Stejskal, Jaroslav

    2012-01-01

    Roč. 520, č. 19 (2012), s. 6088-6094. ISSN 0040-6090 R&D Projects: GA AV ČR IAA400500905; GA AV ČR IAA100500902; GA ČR GAP205/12/0911 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : polyaniline * thin films * infrared spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.604, year: 2012

  19. Factors affecting surface and release properties of thin PDMS films

    DEFF Research Database (Denmark)

    Vudayagiri, Sindhu; Junker, Michael Daniel; Skov, Anne Ladegaard

    2013-01-01

    -strain in the films which affect the overall performance of the films. The current research is directed towards investigating factors affecting the peel force and release of thin, corrugated polydimethylsiloxane films used in DEAP films. It has been shown that doping the PDMS films with small quantities of...

  20. Titanium diffusion in gold thin films

    International Nuclear Information System (INIS)

    In the present study, diffusion phenomena in titanium/gold (Ti/Au) thin films occurring at temperatures ranging between 200 and 400 oC are investigated. The motivation is twofold: the first objective is to characterize Ti diffusion into Au layer as an effect of different heat-treatments. The second goal is to prove that the implementation of a thin titanium nitride (TiN) layer between Ti and Au can remarkably reduce Ti diffusion. It is observed that Ti atoms can fully diffuse through polycrystalline Au thin films (260 nm thick) already at temperatures as a low as 250 oC. Starting from secondary ion mass spectroscopy data, the overall diffusion activation energy ΔE = 0.66 eV and the corresponding pre-exponential factor D0 = 5 x 10-11 cm2/s are determined. As for the grain boundary diffusivity, both the activation energy range 0.54 gb 0Dgb0 = 1.14 x 10-8 cm2/s are obtained. Finally, it is observed that the insertion of a thin TiN layer (40 nm) between gold and titanium acts as an effective diffusion barrier up to 400 oC.

  1. Microstructure of YBCO thin films prepared by TFA-MOD method

    International Nuclear Information System (INIS)

    The microstructure of the recently developed coated conductors was investigated by using electron back scatter diffraction pattern (EBSP). We prepared TFA (trifluoroacetates)-MOD (metal organic deposition) derived YBa2Cu3O7-x (YBCO) films on CeO2/LaMnO3/IBAD-MgO/Gd2Zr2O7/Hastelloy C276 substrates of 1 cm-width. The EBSP observation showed that there was a difference of surface microstructure between the midsection and the end of TFA-MOD YBCO film layer in the direction of width. This is attributed not to the local difference of the biaxial texture of CeO2 top layer but to the local difference of growth condition during TFA-MOD process.

  2. Microstructure of YBCO thin films prepared by TFA-MOD method

    Science.gov (United States)

    Nagino, I.; Matsumoto, K.; Adachi, H.; Miyata, S.; Yoshizumi, M.; Izumi, T.; Shiohara, Y.

    2010-11-01

    The microstructure of the recently developed coated conductors was investigated by using electron back scatter diffraction pattern (EBSP). We prepared TFA (trifluoroacetates)-MOD (metal organic deposition) derived YBa 2Cu 3O 7-x (YBCO) films on CeO 2/LaMnO 3/IBAD-MgO/Gd 2Zr 2O 7/Hastelloy C276 substrates of 1 cm-width. The EBSP observation showed that there was a difference of surface microstructure between the midsection and the end of TFA-MOD YBCO film layer in the direction of width. This is attributed not to the local difference of the biaxial texture of CeO 2 top layer but to the local difference of growth condition during TFA-MOD process.

  3. Surface sensitive analysis of YBCO thin films

    International Nuclear Information System (INIS)

    Successful cleaning and polishing of a set of YBa2Cu3O7-δ(YBCO) thin films prepared by pulsed laser deposition (PLD) and chemical solution deposition (CSD) have been performed. The roughness of the films was reduced to a value of less than 5 nm, which opens a way to apply local surface sensitive techniques even on formerly very rough samples (some hundred nm peak-to-valley) such as CSD YBCO films. As one application flux lines of YBCO films were imaged with the omicron cryogenic SFM in MFM mode. The knowledge about geometry and distribution of artificial nanodefects in the interior of the film is crucial for further improvement of superconducting properties of these materials. The above mentioned polishing procedure has been further developed to prepare smooth low angle wedges of such samples. This offers the possibility to obtain depth dependent information with different surface sensitive scanning techniques. A high resolution electron backscattered diffraction image on the polished wedge of CSD YBCO sample reveals the homogeneous distribution of non superconducting BaHfO3 nanoparticles in the whole volume of the film

  4. Thin Film Deposition Using Energetic Ions

    Directory of Open Access Journals (Sweden)

    Stephan Mändl

    2010-07-01

    Full Text Available 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.

  5. Supramolecular structure of electroactive polymer thin films

    Science.gov (United States)

    Kornilov, V. M.; Lachinov, A. N.; Karamov, D. D.; Nabiullin, I. R.; Kul'velis, Yu. V.

    2016-05-01

    This paper presents the results of an experimental investigation of the supramolecular structure of polydiphenylenephthalide thin films that exhibit effects of resistive switching. The supramolecular structure of the polymer has been investigated using small-angle neutron scattering in conjunction with atomic force microscopy. It has been found that the internal structure of polymer films consists of structural elements in the form of spheroids. The sizes of the structural elements, which were obtained from the neutron scattering data and analysis of the atomic force microscopy images, correlate well with each other. A model of the formation of polymer layers has been proposed. The observed structural elements in polymer films are formed due to the association of macromolecules in the initial polymer solution.

  6. Magnetization relaxation in sputtered thin permalloy films

    Science.gov (United States)

    Oliveira, R. C.; Rodríguez-Suárez, R. L.; Aguiar, F. M. De; Rezende, S. M.; Fermin, J. R.; Azevedo, A.

    2004-05-01

    In order to understand the underlying phenomena of magnetization damping in metallic thin films, samples of permalloy films were grown by magnetron sputtering, and their 8.6-GHz ferromagnetic resonance linewidth ΔH has been measured as a function of the Permalloy (Py) film thickness t, at room temperature. We made samples of Py(t)/Si(001) and X/Py(t)/X/Si(001), with X=Pd (40Å), and Cr (25Å), with 20Å < t < 200Å. While ΔH scales with t-2 in the bare Py/Si series, it is shown that the damping behavior strongly depends on X in the sandwich samples.

  7. Sulfated cellulose thin films with antithrombin affinity

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Full Text Available Cellulose thin films were chemically modified by in situ sulfation to produce surfaces with anticoagulant characteristics. Two celluloses differing in their degree of polymerization (DP: CEL I (DP 215–240 and CEL II (DP 1300–1400 were tethered to maleic anhydride copolymer (MA layers and subsequently exposed to SO3•NMe3 solutions at elevated temperature. The impact of the resulting sulfation on the physicochemical properties of the cellulose films was investigated with respect to film thickness, atomic composition, wettability and roughness. The sulfation was optimized to gain a maximal surface concentration of sulfate groups. The scavenging of antithrombin (AT by the surfaces was determined to conclude on their potential anticoagulant properties.

  8. Irradiation effects in YBCO thin films

    International Nuclear Information System (INIS)

    Oxide superconductors are very sensitive to electron or ion beam irradiation/implantation. In the past 19 years after high-Tc (HTc) superconductivity was discovered in these materials, many aspects of interactions of accelerated particles with HTc thin films were investigated. In this paper short review of most significant phenomena is given, especially of those important for electronic applications (controllable reduction of critical temperature and critical current density) and their applications for HTc film patterning, fabrication of HTc Josephson junctions and SQUIDs. Some new results in creating 3-d inhomogeneous regions in YBCO superconductors by ion irradiation/implantation and investigation of high harmonic generation in YBCO film modified by 100 keV oxygen ions are presented. (author)

  9. Nanocrystalline silicon based thin film solar cells

    Science.gov (United States)

    Ray, Swati

    2012-06-01

    Amorphous silicon solar cells and panels on glass and flexible substrate are commercially available. Since last few years nanocrystalline silicon thin film has attracted remarkable attention due to its stability under light and ability to absorb longer wavelength portion of solar spectrum. For amorphous silicon/ nanocrystalline silicon double junction solar cell 14.7% efficiency has been achieved in small area and 13.5% for large area modules internationally. The device quality nanocrystalline silicon films have been fabricated by RF and VHF PECVD methods at IACS. Detailed characterizations of the materials have been done. Nanocrystalline films with low defect density and high stability have been developed and used as absorber layer of solar cells.

  10. Plasmonic Based Sensing Using an Array of Au-Metal Oxide Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Joy, N.; Rogers, Phillip H.; Nandasiri, Manjula I.; Thevuthasan, Suntharampillai; Carpenter, Michael A.

    2012-12-04

    An optical plasmonic-based sensing array has been developed and tested for the selective and sensitive detection of H2, CO, and NO2 at a temperature of 500°C in an oxygen-containing background. The three element sensing array used Au nanoparticles embedded in separate thin films of yttria stabilized zirconia (YSZ), CeO2, and TiO2. A peak in the absorbance spectrum due to a localized surface plasmon resonance (LSPR) on the Au nanoparticles was monitored for each film during gas exposures and showed a blue shift in the peak positions for the reducing gases, H2 and CO, and a red shift for the oxidizing gas NO2. A more in-depth look at the sensing response was performed using the multivariate methods of principal component analysis (PCA) analysis and linear discriminant analysis (LDA) on data from across the entire absorbance spectrum range. Qualitative results from both methods showed good separation between the three analytes for both the full array and the Au-TiO2 sample. Quantification of LDA cluster separation using the Mahalanobis distance showed better cluster separation for the array, but there were some instances with the lowest concentrations where the single Au-TiO2 film had better separation than the array. A second method to quantify cluster separation in LDA space was developed using multidimensional volume analysis of the individual cluster volume, overlapped cluster volume and empty volume between clusters. Compared to the individual sensing elements, the array showed less cluster overlap, smaller cluster volumes, and more space between clusters, all of which were expected for improved separability between the analytes.

  11. Scanning tunneling spectroscopy of Pb thin films

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Michael

    2010-12-13

    The present thesis deals with the electronic structure, work function and single-atom contact conductance of Pb thin films, investigated with a low-temperature scanning tunneling microscope. The electronic structure of Pb(111) thin films on Ag(111) surfaces is investigated using scanning tunneling spectroscopy (STS). Quantum size effects, in particular, quantum well states (QWSs), play a crucial role in the electronic and physical properties of these films. Quantitative analysis of the spectra yields the QWS energies as a function of film thickness, the Pb bulk-band dispersion in {gamma}-L direction, scattering phase shifts at the Pb/Ag interface and vacuum barrier as well as the lifetime broadening at anti {gamma}. The work function {phi} is an important property of surfaces, which influences catalytic reactivity and charge injection at interfaces. It controls the availability of charge carriers in front of a surface. Modifying {phi} has been achieved by deposition of metals and molecules. For investigating {phi} at the atomic scale, scanning tunneling microscopy (STM) has become a widely used technique. STM measures an apparent barrier height {phi}{sub a}, which is commonly related to the sample work function {phi}{sub s} by: {phi}{sub a}=({phi}{sub s}+{phi}{sub t}- vertical stroke eV vertical stroke)/2, with {phi}{sub t} the work function of the tunneling tip, V the applied tunneling bias voltage, and -e the electron charge. Hence, the effect of the finite voltage in STM on {phi}{sub a} is assumed to be linear and the comparison of {phi}{sub a} measured at different surface sites is assumed to yield quantitative information about work function differences. Here, the dependence of {phi}{sub a} on the Pb film thickness and applied bias voltage V is investigated. {phi}{sub a} is found to vary significantly with V. This bias dependence leads to drastic changes and even inversion of contrast in spatial maps of {phi}{sub a}, which are related to the QWSs in the Pb

  12. Preparation and characterization of vanadium oxide thin films

    International Nuclear Information System (INIS)

    The thermotropic VO2 films have many applications, since they exhibit semiconductor-conductor switching properties at temperature around 70 grad C. Vanadium oxide thin films were prepared via sol-gel method. Spin coater was used to depose these films on Si/SiO2 and lime glass substrates. Thin films of V2O5 can be reduced to metastable VO2 thin films at the temperature of 450 grad C under the pressure of 10-2 Pa. These films are then converted to thermotropic VO2 at 700 grad C in argon under normal pressure. (authors)

  13. Visible light induced degradation of methylene blue using CeO2/V2O5 and CeO2/CuO catalysts

    International Nuclear Information System (INIS)

    In the present study, the nanocatalysts CeO2, V2O5, CuO, CeO2/V2O5 and CeO2/CuO were synthesized by thermal decomposition method. This method is simple, fast and cost effective compared with other preparation methods. The synthesized catalysts were characterized by different techniques. The XRD and XPS results confirmed the structure and the oxidization states of the nanocomposite materials. DRS results suggested that the prepared CeO2/V2O5 and CeO2/CuO nanocomposites can generate more electrons and holes under visible light irradiation. The photocatalytic activities of prepared catalysts were evaluated using the degradation of aqueous methylene blue solution as a model compound under visible light irradiation. In addition, the nanocomposite (CeO2/V2O5 and CeO2/CuO) materials were employed to degrade the textile effluent under visible light condition. - Highlights: • The catalysts were synthesized via a facile thermal decomposition method which was simple, fast and feasible method. • Degradation of methylene blue and real effluent were carried out under visible light. • The photocatalytic activity of nanocomposite materials is higher than that of single phase material

  14. Investigation of irradiated ferroelectric thin films

    International Nuclear Information System (INIS)

    Irradiation effects on highly oriented Pb1Zr0.53Ti0.47O3 (PZT), Pb0.94La0.06Zr0.65Ti0.35O3 (PLZT-6), and Pb1Zr1O3 (PZ) ferroelectric (FE) and antiferroelectric (AF) thin films are investigated with respect to their possible application as a temperature sensitive element in a new bolometer system for ITER. The PZT and PZ films were deposited by a sol-gel technique on a Pt/TiO2/Si substrate, whereas the PLZT-6 film was deposited by pulsed laser deposition (PLD) on a LSCO/MgO (100) substrate. The dielectric properties, i.e. the hysteresis loop and the dielectric constant of the films, were investigated in a frequency range from 20 Hz to 100 kHz and at temperatures up to 300 deg. C, before and after neutron irradiation to a fast neutron fluence of 5x1021m-2 (E>0.1MeV). The dielectric constant was measured during cooling with 2 deg. C.min-1. The dielectric properties of the films were measured before and after annealing to 300 deg. C. (author)

  15. Thin-liquid-film evaporation at contact line

    Institute of Scientific and Technical Information of China (English)

    Hao WANG; Zhenai PAN; Zhao CHEN

    2009-01-01

    When a liquid wets a solid wall, the extended meniscus near the contact line may be divided into three regions: a nonevaporating region, where the liquid is adsorbed on the wall; a transition region or thin-film region, where effects of long-range molecular forces (disjoining pressure) are felt; and an intrinsic meniscus region, where capillary forces dominate. The thin liquid film, with thickness from nanometers up to micrometers, covering the transition region and part of intrinsic meniscus, is gaining interest due to its high heat transfer rates. In this paper, a review was made of the researches on thin-liquid-film evaporation. The major characteristics of thin film, thin-film modeling based on continuum theory, simulations based on molecular dynamics, and thin-film profile and temperature measurements were summarized.

  16. Theoretical investigation of the thermodynamic properties of metallic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Vu Van [Vietnam Education Publishing House, 81 Tran Hung Dao, Hanoi (Viet Nam); Phuong, Duong Dai [Hanoi National University of Education, 136 Xuan Thuy, Hanoi (Viet Nam); Hoa, Nguyen Thi [University of Transport and Communications, Lang Thuong, Dong Da, Hanoi (Viet Nam); Hieu, Ho Khac, E-mail: hieuhk@duytan.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam)

    2015-05-29

    The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks.

  17. Theoretical investigation of the thermodynamic properties of metallic thin films

    International Nuclear Information System (INIS)

    The thermodynamic properties of metallic thin films with face-centered cubic structure at ambient conditions were investigated using the statistical moment method including the anharmonicity effects of thermal lattice vibrations. The analytical expressions of Helmholtz free energy, lattice parameter, linear thermal expansion coefficient, specific heats at the constant volume and constant pressure were derived in terms of the power moments of the atomic displacements. Numerical calculations of thermodynamic properties have been performed for Au and Al thin films and compared with those of bulk metals. This research proposes that thermodynamic quantities of thin films approach the values of bulk when the thickness of thin film is about 70 nm. - Highlights: • Thermodynamic properties of thin films were investigated using the moment method. • Expressions of Helmholtz energy, expansion coefficient, specific heats were derived. • Calculations for Au, Al thin films were performed and compared with those of bulks

  18. Investigating the interfacial dynamics of thin films

    Science.gov (United States)

    Rosenbaum, Aaron W.

    This thesis probes the interfacial dynamics and associated phenomena of thin films. Surface specific tools were used to study the self-assembly of alkanethiols, the mono- and bilayer dynamics of SF6, and the surface motion of poly(methyl methacrylate). Non-pertubative helium atom scattering was the principal technique used to investigate these systems. A variety of other complementary tools, including scanning tunneling microscopy, electron diffraction, Auger spectroscopy, atomic force microscopy, and ellipsometry were used in tandem with the neutral atom scattering studies. Controlling the spontaneous assembly of alkanethiols on Au(111) requires a better fundamental understanding of the adsorbate-adsorbate and substrate-adsorbate interactions. Our characterization focused on two key components, the surface structure and adsorbate vibrations. The study indicates that the Au(111) reconstruction plays a larger role than anticipated in the low-density phase of alkanethiol monolayers. A new structure is proposed for the 1-decanethiol monolayer that impacts the low-energy vibrational mode. Varying the alkane chain lengths imparts insight into the assembly process via characterization of a dispersionless phonon mode. Studies of SF6 physisorbed on Au(111) bridge surface research on rare gas adsorbates with complicated dynamical organic thin films. Mono- and bilayer coverages of SF6/Au(111) were studied at cryogenic temperatures. Our experiments probed the surface properties of SF6 yielding insights into substrate and coverage effects. The study discovered a dispersionless Einstein oscillation with multiple harmonic overtones. A second layer of SF6 softened the mode, but did not show any indications of bulk or cooperative interactions. The vibrational properties of SF 6 showed both striking similarities and differences when compared with physisorbed rare gases. Lastly, this thesis will discuss studies of thin film poly(methyl methacrylate) on Si. The non-pertubative and

  19. Pulsed laser deposition of pepsin thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kecskemeti, G. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary)]. E-mail: kega@physx.u-szeged.hu; Kresz, N. [Department of Optics and Quantum Electronics, University of Szeged, H-6720 Szeged, Dom ter 9 (Hungary); Smausz, T. [Hungarian Academy of Sciences and University of Szeged, Research Group on Laser Physics, H-6720 Szeged, Dom ter 9 (Hungary); Hopp, B. [Hungarian Academy of Sciences and University of Szeged, Research Group on Laser Physics, H-6720 Szeged, Dom ter 9 (Hungary); Nogradi, A. [Department of Ophthalmology, University of Szeged, H-6720, Szeged, Koranyi fasor 10-11 (Hungary)

    2005-07-15

    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 ({lambda} = 193 nm, FWHM = 30 ns), the applied fluence was varied between 0.24 and 5.1 J/cm{sup 2}. The pressure in the PLD chamber was 2.7 x 10{sup -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{sup 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.

  20. Controllable preparation of CeO2 nanostructure materials and their catalytic activity

    Institute of Scientific and Technical Information of China (English)

    Shan Wenjuan; Guo Hongjuan; Liu Chang; Wang Xiaonan

    2012-01-01

    Well-crystalline CeO2 nanostructures with the morphology ofnanorods and nanocubes were synthesized by a template-free hydrothermal method.X-ray diffraction (XRD),transmission electron microscopy (TEM),Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption measurements were employed to characterize the synthesized materials.The reducibility and catalytic activity of nanostructured CeO2 were examined by hydrogen temperature-programmed reduction (H2-TPR) and CO oxidation.The results showed that CeO2 nanorods could be converted into CeO2 nanocubes with the increasing of the reaction time and the hydrothermal temperature,CeO2 nanorods became longer gradually with the increasing of the concentrations of NaOH.H2-TPR characterization demonstrated that the intense low-temperature reduction peak in the CeO2 nanorods indicated the amount of hydrogen consumed is larger than CeO2 nanocubes.Meantime the CeO2 nanorods enhanced catalytic activity for CO oxidation,the total conversion temperature was 340 ℃.The reasons were that CeO2 nanorods have much smaller crystalline sizes and higher surface areas than CeO2 nanocubes.

  1. Memristive switching in vanadium dioxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Buerger, Danilo; John, Varun; Kovacs, Gyoergy; Skorupa, Ilona; Helm, Manfred; Schmidt, Heidemarie [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany)

    2011-07-01

    Memristive devices exhibit an improved performance at ultra-small scales. The microscopic model for memristive behavior in oxide nanostructures often depends on the distribution of oxygen vacancies and is determined by the cation species. In 2008 HP presented the first bipolar TiO2-based memristor for resistive applications, where the drift of oxygen vacancies causes a change in the resistance of ultrathin TiO2 films which can be locally modified by ion implantation. We prepared vanadium dioxide (VO2) thin films with the reversible metal-insulator phase transition at the thermochromic switching temperature of around 340 K by pulsed laser deposition on (0001)-sapphire substrates and analyzed the electric-pulse-induced thermochromic switching in the VO2 gap region at room temperature due to local heating. As a result, we find the typical pinched hysteresis loop of a memristor, a repeatable switching behavior for billions of voltage pulses and switching times shorter than 50 ns in VO2 thin films.

  2. Powdering characteristics of thin film evaporator, 1

    International Nuclear Information System (INIS)

    Vertical thin film evaporators have been used to concentrate and dry solutions because their rotating swing blades prevent scale from being deposited on the heated surfaces. Powdering capacity of the vertical thin film evaporator was examined experimentally for drying applications of radioactive liquid waste generated from nuclear power plants. As a result, it was found that the powdering capacity increased with the blade rotation, changing significantly in the low ratational region and scarcely in the high rotational region. The powdering capacity in the high rotational region was restricted by the lack of heat flux which was theoretically evaluated for the concentrating process. As the critical factor in the low rotational region was not clear, a visual test apparatus was made to observe flow patterns in the evaporator, and a powdering model was obtained. This model showed that powdering process was obstructed when the liquid film lost its fluidity at high concentration. Based on this model, the powdering process was simulated theoretically with good agreement between calculated and experimental results. (author)

  3. Polarized Neutron Reflectivity Simulation of Ferromagnet/ Antiferromagnet Thin Films

    International Nuclear Information System (INIS)

    This report investigates the current simulating and fitting programs capable of calculating the polarized neutron reflectivity of the exchange-biased ferromagnet/antiferromagnet magnetic thin films. The adequate programs are selected depending on whether nonspin flip and spin flip reflectivities of magnetic thin films and good user interface are available or not. The exchange-biased systems such as Fe/Cr, Co/CoO, CoFe/IrMn/Py thin films have been simulated successfully with selected programs

  4. Overview and Challenges of Thin Film Solar Electric Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Ullal, H. S.

    2008-12-01

    In this paper, we report on the significant progress made worldwide by thin-film solar cells, namely, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). Thin-film photovoltaic (PV) technology status is also discussed in detail. In addition, R&D and technology challenges in all three areas are elucidated. The worldwide estimated projection for thin-film PV technology production capacity announcements are estimated at more than 5000 MW by 2010.

  5. Networking Behavior in Thin Film and Nanostructure Growth Dynamics

    OpenAIRE

    Yuksel, Murat; Karabacak, Tansel; Guclu, Hasan

    2007-01-01

    Thin film coatings have been essential in development of several micro and nano-scale devices. To realize thin film coatings various deposition techniques are employed, each yielding surface morphologies with different characteristics of interest. Therefore, understanding and control of the surface growth is of great interest. In this paper, we devise a novel network-based modeling of the growth dynamics of such thin films and nano-structures. We specifically map dynamic steps taking place du...

  6. Characterizations of photoconductivity of graphene oxide thin films

    Directory of Open Access Journals (Sweden)

    Shiang-Kuo Chang-Jian

    2012-06-01

    Full Text Available Characterizations of photoresponse of a graphene oxide (GO thin film to a near infrared laser light were studied. Results showed the photocurrent in the GO thin film was cathodic, always flowing in an opposite direction to the initial current generated by the preset bias voltage that shows a fundamental discrepancy from the photocurrent in the reduced graphene oxide thin film. Light illumination on the GO thin film thus results in more free electrons that offset the initial current. By examining GO thin films reduced at different temperatures, the critical temperature for reversing the photocurrent from cathodic to anodic was found around 187°C. The dynamic photoresponse for the GO thin film was further characterized through the response time constants within the laser on and off durations, denoted as τon and τoff, respectively. τon for the GO thin film was comparable to the other carbon-based thin films such as carbon nanotubes and graphenes. τoff was, however, much larger than that of the other's. This discrepancy was attributable to the retardation of exciton recombination rate thanks to the existing oxygen functional groups and defects in the GO thin films.

  7. Sputtering materials for VLSI and thin film devices

    CERN Document Server

    Sarkar, Jaydeep

    2010-01-01

    An important resource for students, engineers and researchers working in the area of thin film deposition using physical vapor deposition (e.g. sputtering) for semiconductor, liquid crystal displays, high density recording media and photovoltaic device (e.g. thin film solar cell) manufacturing. This book also reviews microelectronics industry topics such as history of inventions and technology trends, recent developments in sputtering technologies, manufacturing steps that require sputtering of thin films, the properties of thin films and the role of sputtering target performance on overall p

  8. Growth and Characterization of Epitaxial Oxide Thin Films

    OpenAIRE

    Garg, Ashish

    2001-01-01

    Epitaxial oxide thin films are used in many technologically important device applications. This work deals with the deposition and characterization of epitaxial WO3 and SrBi2Ta2O9 (SBT) thin films on single crystal oxide substrates. WO3 thin films were chosen as a subject of study because of recent findings of superconductivity at surfaces and twin boundaries in the bulk form of this oxide. Highly epitaxial thin films would be desirable in order to be able to create a device withi...

  9. Applications of thin-film photovoltaics for space

    Science.gov (United States)

    Landis, Geoffrey A.; Hepp, Aloysius F.

    1991-01-01

    The authors discuss the potential applications of thin-film polycrystalline and amorphous cells for space. There have been great advances in thin-film solar cells for terrestrial applications. Transfer of this technology to space applications could result in ultra low-weight solar arrays with potentially large gains in specific power. Recent advances in thin-film solar cells are reviewed, including polycrystalline copper indium selenide and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon arrays. The possibility of using thin-film multi-bandgap cascade solar cells is discussed.

  10. Thin-Film Photovoltaics: Status and Applications to Space Power

    Science.gov (United States)

    Landis, Geoffrey A.; Hepp, Aloysius F.

    1991-01-01

    The potential applications of thin film polycrystalline and amorphous cells for space are discussed. There have been great advances in thin film solar cells for terrestrial applications; transfer of this technology to space applications could result in ultra low weight solar arrays with potentially large gains in specific power. Recent advances in thin film solar cells are reviewed, including polycrystalline copper iridium selenide and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon alloys. The possibility of thin film multi bandgap cascade solar cells is discussed.

  11. Design and Simulation of the Thin Film Pulse Transformer

    Institute of Scientific and Technical Information of China (English)

    LIU Bao-yuan; SHI Yu; WEN Qi-ye

    2005-01-01

    A new thin film pulse transformer for using in ISND and ADSL systems has been designed based on a domain wall pinning model, the parameters of nano-magnetic thin film such as permeability and coercivity can be calculated. The main properties of the thin film transformer including the size,parallel inductance, Q value and turn ratio have been simulated and optimized. Simulation results show that the thin film transformer can be fairly operated in a frequency range of 0. 001~20 MHz.

  12. Physics of thin films advances in research and development

    CERN Document Server

    Hass, Georg; Vossen, John L

    2013-01-01

    Physics of Thin Films: Advances in Research and Development, Volume 12 reviews advances that have been made in research and development concerning the physics of thin films. This volume covers a wide range of preparative approaches, physics phenomena, and applications related to thin films. This book is comprised of four chapters and begins with a discussion on metal coatings and protective layers for front surface mirrors used at various angles of incidence from the ultraviolet to the far infrared. Thin-film materials and deposition conditions suitable for minimizing reflectance changes with

  13. Role of asphaltenes in stabilizing thin liquid emulsion films.

    Science.gov (United States)

    Tchoukov, Plamen; Yang, Fan; Xu, Zhenghe; Dabros, Tadeusz; Czarnecki, Jan; Sjöblom, Johan

    2014-03-25

    Drainage kinetics, thickness, and stability of water-in-oil thin liquid emulsion films obtained from asphaltenes, heavy oil (bitumen), and deasphalted heavy oil (maltenes) diluted in toluene are studied. The results show that asphaltenes stabilize thin organic liquid films at much lower concentrations than maltenes and bitumen. The drainage of thin organic liquid films containing asphaltenes is significantly slower than the drainage of the films containing maltenes and bitumen. The films stabilized by asphaltenes are much thicker (40-90 nm) than those stabilized by maltenes (∼10 nm). Such significant variation in the film properties points to different stabilization mechanisms of thin organic liquid films. Apparent aging effects, including gradual increase of film thickness, rigidity of oil/water interface, and formation of submicrometer size aggregates, were observed for thin organic liquid films containing asphaltenes. No aging effects were observed for films containing maltenes and bitumen in toluene. The increasing stability and lower drainage dynamics of asphaltene-containing thin liquid films are attributed to specific ability of asphaltenes to self-assemble and form 3D network in the film. The characteristic length of stable films is well beyond the size of single asphaltene molecules, nanoaggregates, or even clusters of nanoaggregates reported in the literature. Buildup of such 3D structure modifies the rheological properties of the liquid film to be non-Newtonian with yield stress (gel like). Formation of such network structure appears to be responsible for the slower drainage of thin asphaltenes in toluene liquid films. The yield stress of liquid film as small as ∼10(-2) Pa is sufficient to stop the drainage before the film reaches the critical thickness at which film rupture occurs. PMID:24564447

  14. Atomic Structure Control of Silica Thin Films on Pt(111)

    KAUST Repository

    Crampton, Andrew S

    2015-05-27

    Metal oxide thin films grown on metal single crystals are commonly used to model heterogeneous catalyst supports. The structure and properties of thin silicon dioxide films grown on metal single crystals have only recently been thoroughly characterized and their spectral properties well established. We report the successful growth of a three- dimensional, vitreous silicon dioxide thin film on the Pt(111) surface and reproduce the closed bilayer structure previously reported. The confirmation of the three dimensional nature of the film is unequivocally shown by the infrared absorption band at 1252 cm−1. Temperature programmed desorption was used to show that this three-dimensional thin film covers the Pt(111) surface to such an extent that its application as a catalyst support for clusters/nanoparticles is possible. The growth of a three-dimensional film was seen to be directly correlated with the amount of oxygen present on the surface after the silicon evaporation process. This excess of oxygen is tentatively attributed to atomic oxygen being generated in the evaporator. The identification of atomic oxygen as a necessary building block for the formation of a three-dimensional thin film opens up new possibilities for thin film growth on metal supports, whereby simply changing the type of oxygen enables thin films with different atomic structures to be synthesized. This is a novel approach to tune the synthesis parameters of thin films to grow a specific structure and expands the options for modeling common amorphous silica supports under ultra high vacuum conditions.

  15. Modelling the tribology of thin film interfaces

    CERN Document Server

    Zugic, R

    2000-01-01

    substrate). Within each group of simulations, three lubricant film thicknesses are studied to examine the effect of varying lubricant thickness. Statistical data are collected from each simulation and presented in this work. Via these data, together with the evolution, of atomic and molecular configurations, a very detailed picture of the properties of this thin film interface is presented. In particular, we conclude that perfluoropolyether lubricant forms distinct molecular layers when confined between two substrates, the rate of heat generation under shearing conditions typical of those in a head-disk interface is insufficient for thermal mechanisms to result directly in lubricant degradation, and mechanical stresses attained in the head-disk interface are unlikely to result in any significant degree of lubricant degradation. This thesis examines the tribology of a head-disk interface in an operating hard disk drive via non-equilibrium molecular dynamics computer simulations. The aim of this work is to deri...

  16. Electrical Resistance Tomography of Conductive Thin Films

    CERN Document Server

    Cultrera, Alessandro

    2016-01-01

    The Electrical Resistance Tomography (ERT) technique is applied to the measurement of sheet conductance maps of both uniform and patterned conductive thin films. Images of the sheet conductance spatial distribution, and local conductivity values are obtained. Test samples are tin oxide films on glass substrates, with electrical contacts on the sample boundary, some samples are deliberately patterned in order to induce null conductivity zones of known geometry while others contain higher conductivity inclusions. Four-terminal resistance measurements among the contacts are performed with a scanning setup. The ERT reconstruction is performed by a numerical algorithm based on the total variation regularization and the L-curve method. ERT correctly images the sheet conductance spatial distribution of the samples. The reconstructed conductance values are in good quantitative agreement with independent measurements performed with the van der Pauw and the four-point probe methods.

  17. Levan nanostructured thin films by MAPLE assembling.

    Science.gov (United States)

    Sima, Felix; Mutlu, Esra Cansever; Eroglu, Mehmet S; Sima, Livia E; Serban, Natalia; Ristoscu, Carmen; Petrescu, Stefana M; Oner, Ebru Toksoy; Mihailescu, Ion N

    2011-06-13

    Synthesis of nanostructured thin films of pure and oxidized levan exopolysaccharide by matrix-assisted pulsed laser evaporation is reported. Solutions of pure exopolysaccharides in dimethyl sulfoxide were frozen in liquid nitrogen to obtain solid cryogenic pellets that have been used as targets in pulsed laser evaporation experiments with a KrF* excimer source. The expulsed material was collected and assembled onto glass slides and Si wafers. The contact angle studies evidenced a higher hydrophilic behavior in the case of oxidized levan structures because of the presence of acidic aldehyde-hydrogen bonds of the coating formed after oxidation. The obtained films preserved the base material composition as confirmed by Fourier transform infrared spectroscopy. They were compact with high specific surface areas, as demonstrated by scanning electron and atomic force microscopy investigations. In vitro colorimetric assays revealed a high potential for cell proliferation for all coatings with certain predominance for oxidized levan. PMID:21520921

  18. Analysis on mechanism of thin film lubrication

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chaohui; LUO Jianbin; HUANG Zhiqiang

    2005-01-01

    It is an important concern to explore the properties and principles of lubrication at nano or molecularscale. For a long time, measurement apparatus for filmthickness of thin film lubrication (TFL) at nano scale havebeen devised on the basis of superthin interferometry technique. Many experiments were carried out to study the lubrication principles of TFL by taking advantages of aforementioned techniques, in an attempt to unveil the mechanism of TFL. Comprehensive experiments were conducted to explore the distinctive characteristics of TFL. Results show that TFL is a distinctive lubrication state other than any known lubrication ones, and serves as a bridge between elastohydrodynamic lubrication (EHL) and boundary lubrication (BL). Two main influence factors of TFL are the solid surface effects and the molecular properties of the lubricant, whose combination effects result in alignment of liquid molecules near the solid surfaces and subsequently lubrication with ordered film emerged. Results of theoretical analysis considering microstructure are consistent with experimental outcomes, thus validating the proposed mechanism.

  19. Separation Efficiency of Thin-film Evaporators

    Institute of Scientific and Technical Information of China (English)

    R.Billet

    2004-01-01

    The recovery of contaminants and useful substances from liquid wastes, the purification of production effluents and the separation of thermally instable mixtures are some of the multivarious applications of thin-film distillors in many processes of the chemical and allied industries and of the food industries. In a study carried out in pilot plants with distillation test systems there was found a good agreement between the experimental separation results and those obtained by computing with a theorectical model; the latter is based on the assumption of phase equilibrium between the vapour formed on an infinitely small element of area in a liquid film of any given concentric periphery of the vertically arranged evaporator. These tests were perfomed under various phase loads.

  20. Thermoviscoelastic models for polyethylene thin films

    Science.gov (United States)

    Li, Jun; Kwok, Kawai; Pellegrino, Sergio

    2016-02-01

    This paper presents a constitutive thermoviscoelastic model for thin films of linear low-density polyethylene subject to strains up to yielding. The model is based on the free volume theory of nonlinear thermoviscoelasticity, extended to orthotropic membranes. An ingredient of the present approach is that the experimentally inaccessible out-of-plane material properties are determined by fitting the model predictions to the measured nonlinear behavior of the film. Creep tests, uniaxial tension tests, and biaxial bubble tests are used to determine the material parameters. The model has been validated experimentally, against data obtained from uniaxial tension tests and biaxial cylindrical tests at a wide range of temperatures and strain rates spanning two orders of magnitude.

  1. Thin-film optical shutter. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Matlow, S.L.

    1981-02-01

    A specific embodiment of macroconjugated macromolecules, the poly (p-phenylene)'s, has been chosen as the one most likely to meet all of the requirements of the Thin Film Optical Shutter project (TFOS). The reason for this choice is included. In order to be able to make meaningful calculations of the thermodynamic and optical properties of the poly (p-phenylene)'s a new quantum mechanical method was developed - Equilibrium Bond Length (EBL) Theory. Some results of EBL Theory are included.

  2. Thin Film Photovoltaics: Markets and Industry

    OpenAIRE

    Arnulf Jäger-Waldau

    2012-01-01

    Since 2000, total PV production increased almost by two orders of magnitude, with a compound annual growth rate of over 52%. The most rapid growth in annual cell and module production over the last five years could be observed in Asia, where China and Taiwan together now account for about 60% of worldwide production. Between 2005 and 2009, thin film production capacity and volume increased more than the overall industry but did not keep up in 2010 and 2011 due to the rapid price decline for s...

  3. Fabrication of Optical Tunable Helical Thin Films

    Institute of Scientific and Technical Information of China (English)

    Linxin Hu; Peng Wang; Xingyang Wan; Shaoji Jiang

    2012-01-01

    Circular polarization selection of light is an important property of helical micro-nanostructure. The helical thin films fabricated by glancing angle deposition can provide both circular polarization selection and wavelength tuning in this work. Their selective transmissions were depicted in calculations and experiments. The wave- length tuning mechanism was revealed as the relationship between peak wavelength and deposition parameters. Therefore, tunable circular polarization components can be designed according to the mechanism mentioned above and fabricated by glancing angle deposition techniques. Potential applications include tunable optical filters, optical pulse-shapers, biosensors etc.

  4. Stable localized patterns in thin liquid films

    Science.gov (United States)

    Deissler, Robert J.; Oron, Alexander

    1992-01-01

    A two-dimensional nonlinear evolution equation is studied which describes the three-dimensional spatiotemporal behavior of the air-liquid interface of a thin liquid film lying on the underside of a cooled horizontal plate. It is shown that the equation has a Liapunov functional, and this fact is exploited to demonstrate that the Marangoni effect can stabilize the destabilizing effect of gravity (the Rayleigh-Taylor instability), allowing for the existence of stable localized axisymmetric solutions for a wide range of parameter values. Various properties of these structures are discussed.

  5. Birefringent thin films and polarizing elements

    CERN Document Server

    Hodgkinson, Ian J

    1997-01-01

    This book describes the propagation of light in biaxial media, the properties of biaxial thin films, and applications such as birefringent filters for tuning the wavelength of dye lasers.A novel feature of the first part is the parallel treatment of Stokes, Jones, and Berreman matrix formalisms in a chapter-by-chapter development of wave equations, basis vectors, transfer matrices, reflection and transmission equations, and guided waves. Computational tools for MATLAB are included.The second part focuses on an emerging planar technology in which anisotropic microstructures are formed by obliqu

  6. Mechanical properties of optical thin films

    Czech Academy of Sciences Publication Activity Database

    Tomáštík, J.; Čtvrtlík, R.; Šebestová, Hana; Schovánek, Petr; Jankůj, J.; Hrabovský, Miroslav

    Prague : ČVUT Technical University in Prague, 2012 - (Růžička, M.; Doubrava, K.; Horák, Z.), s. 469-476 ISBN 978-80-01-05060-6. [EAN 2012 - 50th Annual Conference on Experimental Stress Analysis. Tábor (CZ), 04.06.2012-07.06.2012] R&D Projects: GA TA ČR TA01010517 Institutional research plan: CEZ:AV0Z10100522 Keywords : thin films * mechanical properties * nanoindentation * scratch test Subject RIV: BH - Optics, Masers, Lasers

  7. Experiments of MAPLE thin film technology

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Miroslav; Kocourek, Tomáš; Remsa, Jan; Cristescu, R.; Mihailescu, I. N.; Dybal, Jiří; Pleštil, Josef

    Bellingham: SPIE, 2007 - (Atanasov, P.; Dreischuh, T.; Gateva, S.; Kovachev, L.), 6604OU/1-6604OU/7. (Proceedings of SPIE. 6604). ISBN 978-0-8194-6742-3. [International School on Quantum Electronics /14./. Sunny Beach (BG), 18.09.2006-22.09.2006] R&D Projects: GA ČR GA202/06/0216 Institutional research plan: CEZ:AV0Z10100522; CEZ:AV0Z40500505 Keywords : organic molecules * thin film s * PLD * MAPLE Subject RIV: BH - Optics, Masers, Lasers

  8. Optical and Nonlinear Optical Response of Light Sensor Thin Films

    OpenAIRE

    Weisz, S.Z.; O. Resto; Fonseca, F; Fernandez, L. F.E.; Vikhnin, V. S.; O. Vasquez; A. J. Rua; H. Liu

    2005-01-01

    For potential ultrafast optical sensor application, both VO2 thin films and nanocomposite crystal-Si enriched SiO2 thin films grown on fused quartz substrates were successfully prepared using pulsed laser deposition (PLD) and RF co-sputtering techniques. In photoluminescence (PL) measurement c-Si/SiO2 film contains nanoparticles of crystal Si exhibits strong red emission with the band maximum ranging from 580 to 750 nm. With ultrashort pulsed laser excitation all films show extremely intense ...

  9. High power impulse magnetron sputtering of CIGS thin films for high efficiency thin film solar cells

    Czech Academy of Sciences Publication Activity Database

    Olejníček, Jiří; Hubička, Zdeněk; Kohout, Michal; Kšírová, Petra; Kment, Štěpán; Brunclíková, Michaela; Čada, Martin; Darveau, S.A.; Exstrom, C.L.

    2014-01-01

    Roč. 1, č. 3 (2014), s. 135-137. ISSN 2336-2626 R&D Projects: GA MŠk LH12045 Institutional support: RVO:68378271 Keywords : CIGS * HiPIMS * emission spectroscopy * thin films * magnetron sputtering Subject RIV: BL - Plasma and Gas Discharge Physics http://fyzika.feld.cvut.cz/misc/ppt/articles/2014/olejnicek.pdf

  10. Nitrogen incorporation in sputter deposited molybdenum nitride thin films

    International Nuclear Information System (INIS)

    In this paper, the authors report on the high temperature performance of sputter deposited molybdenum (Mo) and molybdenum nitride (Mo2N) 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

  11. Nitrogen incorporation in sputter deposited molybdenum nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stöber, Laura, E-mail: laura.stoeber@tuwien.ac.at; Patocka, Florian, E-mail: florian.patocka@tuwien.ac.at; Schneider, Michael, E-mail: michael.schneider@tuwien.ac.at; Schmid, Ulrich, E-mail: ulrich.e366.schmid@tuwien.ac.at [Institute of Sensor and Actuator Systems, TU Wien, Gußhausstraße 27-29, A-1040 Vienna (Austria); Konrath, Jens Peter, E-mail: jenspeter.konrath@infineon.com; Haberl, Verena, E-mail: verena.haberl@infineon.com [Infineon Technologies Austria AG, Siemensstraße 2, 9500 Villach (Austria)

    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.

  12. High Tc thin film and device development

    Energy Technology Data Exchange (ETDEWEB)

    Betts, K.; Burbank, M.B.; Cragg, A.; Fife, A.A.; Kubik, P.R.; Lee, S.; Chaklader, A.C.D.; Roemer, G.; Heinrich, B.; Chrzanowski, J.

    1989-03-01

    Thin films of the high Tc superconductor YBa/sub 2/Cu/sub 3/O/sub y/ have been deposited on various substrates by diode and magnetron sputtering using bulk sintered targets. These films have been analyzed by a variety of methods - SEM, X-rays, Electron Beam Microprobe, Mass Spectrometry and Raman Spectroscopy. The stoichiometries of the films have been measured as a function of the radial position from the centre of the sputtered beam at a fixed target-substrate distance. Patterning of the films has been carried out to form planar structures such as strip lines, microbridges and RF SQUIDs. DC current-voltage characteristics of the microbridges were measured as a function of temperature. RF SQUID behaviour has been observed for single loop devices and their properties established at 4.2 K and higher temperatures. Flux locked noise spectra with a 1/f noise power response were recorded in the frequency range 0.01 to approx.100 Hz. RF SQUID signals have been observed for temperatures up to 55 K.

  13. Experimental evidence for self-assembly of CeO2 particles in solution: Formation of single-crystalline porous CeO2 nanocrystals

    DEFF Research Database (Denmark)

    Tan, Hui Ru; Tan, Joyce Pei Ying; Boothroyd, Chris;

    2012-01-01

    Single-crystalline porous CeO2 nanocrystals, with sizes of ∼20 nm and pore diameters of 1-2 nm, were synthesized successfully using a hydrothermal method. Using electron tomography, we imaged the three-dimensional structure of the pores in the nanocrystals and found that the oriented aggregation of...... small CeO2 nanoparticles resulted in the growth of CeO2 nanocrystals with an irregular truncated octahedral shape and pores extending along the 〈110〉 directions. Oxygen vacancies were found on the crystal surfaces and internal walls of the pores by scanning transmission electron microscopy and electron...... energy-loss spectroscopy. The oxygen vacancies might play an important role in oxygen diffusion in the crystals and the catalytic activities of single-crystalline porous CeO 2 structures. © 2011 American Chemical Society....

  14. Influence of nanometric CeO2 coating on high temperature oxidation of Cr

    Institute of Scientific and Technical Information of China (English)

    Jin Huiming; Zhang Linnan; Liu Xiaojun

    2007-01-01

    Isothermal and cyclic oxidation behavior of chromium and its superficially applied nanometric CeO2 samples were studied at 900℃ in air. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and high resolution electronic microscopy (HREM) were used to examine the morphology and micro-structure of oxide films. It was found that ceria addition greatly improved the anti-oxidation ability of Cr both in isothermal and cyclic oxidizing experiments. Acoustic emission (AE) technique was used in situ to monitor the cracking and spalling of oxide films, and AE signals were analyzed in time-domain and number-domain according to the related oxide fracture model. Laser Raman spectrometer was also used to study the stress status of oxide films formed on Cr with and without ceria. The main reason for the improvement in anti-oxidation of chromium was that ceria greatly reduced the growing speed and grain size of Cr2O3. This fine-grained Cr2O3 oxide film might have better high temperature plasticity and could relieve parts of compressive stress by means of creeping, and maintained the ridge character and relatively low internal stress level. Meanwhile, ceria application reduced the size and the number of interfacial defects, while remarkably enhanced the adhesive property of Cr2O3 oxide scale formed on Cr substrate.

  15. Novel nanostructured CeO2 as efficient catalyst for energy and environmental applications

    Indian Academy of Sciences (India)

    Sumanta Kumar Meher; G Ranga Rao

    2014-03-01

    We report here versatile methods to engineer the microstructure and understand the fundamental physicochemical properties of CeO2 to improve its catalytic viability for practical applications. In this context, different morphologies of CeO2 are synthesized using tailored homogeneous precipitation methods and characterized by XRD, BET, SEM and TPR methods. The shuttle-shaped CeO2 prepared under hydrothermal condition shows higher surface area and low-temperature reducibility. The 0.5 wt% Pt-impregnated shuttle-shaped CeO2 shows lower-temperature CO oxidation behaviour as compared to its bulk-like CeO2 (with 0.5 wt% Pt) counterpart, synthesized by conventional-reflux method. Further, nanorod morphology of CeO2 prepared with Cl−as counter ion shows lower-temperature oxidation of soot as compared to the mesoflower morphology of CeO2, prepared with NO$^{−}_{3}$ as counter ion in the reaction medium. Further, linear sweep voltammetry, chronopotentiometry and CO-stripping voltammetry studies are performed to evaluate the promoting activity of CeO2 to Pt/C for ethanol electro-oxidation reaction in acidic media. Results show that CeO2 provides active triple-phase-interfacial sites for suitable adsorption of OH species which effectively oxidize the COads on Pt/C. The results presented here are significant in the context of understanding the physicochemical fine prints of CeO2 and CeO2 based hetero-nanocomposites for their suitability to important catalytic and energy-related applications.

  16. Photocatalytic degradation mechanisms of CeO2/Tb2O3 nanotubes

    International Nuclear Information System (INIS)

    Highlights: • CeO2/Tb2O3 nanotubes have been synthesized using the surfactant free co-precipitation method. • HRTEM images, XPS spectra, and EDAX profiles showed that the as-synthesized samples were CeO2/Tb2O3 nanotubes. • Photocatalytic activity of the synthesized catalysts was evaluated by degrading Methylene blue under visible light irradiation. • Estimated rate constants for the CeO2 nanoparticles and the CeO2/Tb2O3 nanotubes were 0.0134 and 0.0317 min−1, respectively. • Photodegradation efficiency of CeO2/Tb2O3 nanotubes was 93% after 75 min. - Abstract: CeO2/Tb2O3 nanotubes (NTs) have been synthesized using the surfactant free co-precipitation method. High resolution transmission electron microscopy (HRTEM) images, X-ray spectroscopy (XPS) spectra, and energy dispersive X-ray (EDAX) profiles showed that the as-synthesized samples were CeO2/Tb2O3 NTs. The photocatalytic activity of the synthesized catalysts was evaluated by degrading Methylene blue (MB) under visible light irradiation. The fitting of the absorbance maximum as a function of time showed that the photodegradation of the MB followed pseudo-first-order reaction kinetics. The estimated rate constants for the CeO2 NPs and the CeO2/Tb2O3 NTs were found to be 0.0134 and 0.0317 min−1, respectively. The photodegradation efficiency of CeO2/Tb2O3 nanotubes was 93% after 75 min, which was found to be higher than those of CeO2 NPs (66%)

  17. CLSM and UV-VIS researches on polyoxadiazoles thin films

    Directory of Open Access Journals (Sweden)

    J. Weszka

    2012-06-01

    Full Text Available Purpose: The purpose of this paper was to analyse the surface morphology and optical properties of polyoxadiazoles thin films.Design/methodology/approach: A few different conducting polymers were dissolved in N-methyl-2-pyrrolid(inone. Then the solutions were deposited on a glass substrate by spin coating method with a different spin rate. Changes in surface topography and optical properties were observed. A confocal laser scanning microscope CLSM Zeiss LSM 5 Exciter has been used. Photos have been taken from area of 120 x 120 microns.Findings: The analysis of images and spectra has confirmed that the quality of thin films depends upon the used polymers. It was also observed that the parameters of the spin coating method have significant effect on the morphology and the optical properties. The spin rate has got a strong impact on them.Research limitations/implications: The morphology and optical properties of polyoxadiazoles thin films has been described. This paper include description how the spin rate influence on the polymer thin films. In order to use a polymer thin film in photovoltaics or optoelectronics it must have a high internal transmission density. Further research of polymer thin films are recommended.Practical implications: The spin coating method allows to deposit a uniform thin films. It is important to know how the spin rate influence on the thin films properties. It is also important to find a new use for this group of material engineering in photovoltaic or optoelectronics devices.Originality/value: The good properties of thin films make them suitable for various applications. The value of this paper is defining the optimal parameters of spin-coating technology for polyoxadiazoles thin films. The results allow the choosing optimal parameters of the deposition process. Spin coating is a very good method to obtain thin films which are obligated to have the same thickness over the whole surface.

  18. Optical characteristics of the thin-film scintillator detector

    International Nuclear Information System (INIS)

    A study of the thin-film detector (TFD) was made in which various light guide and scintillator film support configurations were tested for efficiency of light coupling. Masking of selected portions of the photomultiplier (PM) tube face revealed the extent to which emitted light was received at the exposed PM surfaces. By blocking off selected areas of the scintillator film surface from direct view of the PM tube faces, a measure of the light-guiding efficiency of the film and its support could be estimated. The picture that emerges is that, as the light which is initially trapped in the thin film spreads radially outward from the ion entrance/exit point, it is scattered out of the film by minute imperfections. Optimum signals were obtained by a configuration in which the thin scintillator film was supported on a thin rectangular Celluloid frame inserted within a highly polished metal cylindrical sleeve

  19. Optical thin film metrology for optoelectronics

    International Nuclear Information System (INIS)

    The manufacturing of optoelectronic thin films is of key importance, because it underpins a significant number of industries. The aim of the European joint research project for optoelectronic thin film characterization (IND07) in the European Metrology Research Programme of EURAMET is to develop optical and X-ray metrologies for the assessment of quality as well as key parameters of relevant materials and layer systems. This work is intended to be a step towards the establishment of validated reference metrologies for the reliable characterization, and the development of calibrated reference samples with well-defined and controlled parameters. In a recent comprehensive study (including XPS, AES, GD-OES, GD-MS, SNMS, SIMS, Raman, SE, RBS, ERDA, GIXRD), Abou-Ras et al. (Microscopy and Microanalysis 17 [2011] 728) demonstrated that most characterization techniques have limitations and bottle-necks, and the agreement of the measurement results in terms of accurate, absolute values is not as perfect as one would expect. This paper focuses on optical characterization techniques, laying emphasis on hardware and model development, which determine the kind and number of parameters that can be measured, as well as their accuracy. Some examples will be discussed including optical techniques and materials for photovoltaics, biosensors and waveguides.

  20. Antimony selenide thin-film solar cells

    Science.gov (United States)

    Zeng, Kai; Xue, Ding-Jiang; Tang, Jiang

    2016-06-01

    Due to their promising applications in low-cost, flexible and high-efficiency photovoltaics, there has been a booming exploration of thin-film solar cells using new absorber materials such as Sb2Se3, SnS, FeS2, CuSbS2 and CuSbSe2. Among them, Sb2Se3-based solar cells are a viable prospect because of their suitable band gap, high absorption coefficient, excellent electronic properties, non-toxicity, low cost, earth-abundant constituents, and intrinsically benign grain boundaries, if suitably oriented. This review surveys the recent development of Sb2Se3-based solar cells with special emphasis on the material and optoelectronic properties of Sb2Se3, the solution-based and vacuum-based fabrication process and the recent progress of Sb2Se3-sensitized and Sb2Se3 thin-film solar cells. A brief overview further addresses some of the future challenges to achieve low-cost, environmentally-friendly and high-efficiency Sb2Se3 solar cells.

  1. Optical thin film metrology for optoelectronics

    Science.gov (United States)

    Petrik, Peter

    2012-12-01

    The manufacturing of optoelectronic thin films is of key importance, because it underpins a significant number of industries. The aim of the European joint research project for optoelectronic thin film characterization (IND07) in the European Metrology Research Programme of EURAMET is to develop optical and X-ray metrologies for the assessment of quality as well as key parameters of relevant materials and layer systems. This work is intended to be a step towards the establishment of validated reference metrologies for the reliable characterization, and the development of calibrated reference samples with well-defined and controlled parameters. In a recent comprehensive study (including XPS, AES, GD-OES, GD-MS, SNMS, SIMS, Raman, SE, RBS, ERDA, GIXRD), Abou-Ras et al. (Microscopy and Microanalysis 17 [2011] 728) demonstrated that most characterization techniques have limitations and bottle-necks, and the agreement of the measurement results in terms of accurate, absolute values is not as perfect as one would expect. This paper focuses on optical characterization techniques, laying emphasis on hardware and model development, which determine the kind and number of parameters that can be measured, as well as their accuracy. Some examples will be discussed including optical techniques and materials for photovoltaics, biosensors and waveguides.

  2. Ti-Cr-Al-O Thin Film Resistors

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, A F; Hayes, J P

    2002-03-21

    Thin films of Ti-Cr-Al-O are produced for use as an electrical resistor material. The films are rf sputter deposited from ceramic targets using a reactive working gas mixture of Ar and O{sub 2}. Vertical resistivity values from 10{sup 4} to 10{sup 10} Ohm-cm are measured for Ti-Cr-Al-O films. The film resistivity can be design selected through control of the target composition and the deposition parameters. The Ti-Cr-Al-O thin film resistor is found to be thermally stable unlike other metal-oxide films.

  3. The preparation and refractive index of BST thin films

    International Nuclear Information System (INIS)

    Radio-frequency magnetron sputtering technique is used to deposit Ba0.65Sr0.35TiO3 (BST) thin films on fused quartz substrates. In order to prepare the high-quality BST thin films, the crystallization and microstructure of the films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). More intense characteristic diffraction peaks and better crystallization can be observed in BST thin films deposited at 600 deg. C and subsequently annealed at 700 deg. C. The refractive index of the films is determined from the measured transmission spectra. The dependences of the refractive index on the deposition parameters of BST thin films are different. The refractive index of the films increases with the substrate temperature. At lower sputtering pressure, the refractive index increases from 1.797 to 2.197 with pressure increase. However, when the pressure increases up to 3.9 Pa, the refractive index reduces to 1.86. The oxygen to argon ratio also plays an important effect on the refractive index of the films. It has been found that the refractive index increases with increase in the ratio of oxygen to argon. The refractive index of BST thin films is strongly dependent on the annealing temperature, which also increases as the annealing temperature ascends. In a word, the refractive index of BST thin films is finally affected by the films' microstructure and texture

  4. Polycystalline silicon thin films for electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Christian Claus

    2012-01-15

    For the thin polycrystalline Si films fabricated with the aluminium-induced-layer-exchange (ALILE) process a good structural quality up to a layer-thickness value of 10 nm was determined. For 5 nm thick layers however after the layer exchange no closes poly-silicon film was present. In this case the substrate was covered with spherically arranged semiconductor material. Furthermore amorphous contributions in the layer could be determined. The electrical characterization of the samples at room temperature proved a high hole concentration in the range 10{sup 18} cm{sup -3} up to 9.10{sup 19} cm{sup -3}, which is influenced by the process temperature and the layer thickness. Hereby higher hole concentrations at higher process temperatures and thinner films were observed. Furthermore above 150-200 K a thermically activated behaviour of the electrical conductivity was observed. At lower temperatures a deviation of the measured characteristic from the exponential Arrhenius behaviour was determined. For low temperatures (below 20 K) the conductivity follows the behaviour {sigma}{proportional_to}[-(T{sub 0}/T){sup 1/4}]. The hole mobility in the layers was lowered by a passivation step, which can be explained by defect states at the grain boundaries. The for these very thin layers present situation was simulated in the framework of the model of Seto, whereby both the defect states at the grain boundaries (with an area density Q{sub t}) and the defect states at the interfaces (with an area density Q{sub it}) were regarded. By this the values Q{sub t}{approx}(3-4).10{sup 12} cm{sup -2} and Q{sub it}{approx}(2-5).10{sup 12} cm{sup -2} could be determined for these thin ALILE layers on quartz substrates. Additionally th R-ALILE process was studied, which uses the reverse precursor-layer sequence substrate/amorphous silicon/oxide/aluminium. Hereby two steps in the crystallization process of the R-ALILE process were found. First a substrate/Al-Si mixture/poly-Si layer structure

  5. Anomalous compressive behavior in CeO2 nanocubes under high pressure

    DEFF Research Database (Denmark)

    Ge, M. Y.; Fang, Y. Z.; Wang, H.;

    2008-01-01

    is found to be 10 GPa for 4.7 nm and 16 GPa for 5.6 nm CeO2 nanocubes. The particle size dependence of the threshold pressure for the hardening of CeO2 nanoparticles is quite unusual. First-principles electronic calculations show that the increased bulk modulus of the nanocrystal is due...

  6. The NO2 sensing ITO thin films prepared by ultrasonic spray pyrolysis

    OpenAIRE

    Jianzhong Gu; Minghua Lu; Zheng Qin; Minghong Wu; Zheng Jiao

    2003-01-01

    In this paper ITO thin films were deposited on alumina substrates by ultrasonic spray pyrolysis. The NO2 sensing properties of ITO thin films were investigated. The results show ITO thin films have good sensitivity to nitrogen dioxide.

  7. Use of thin films in high-temperature superconducting bearings.

    Energy Technology Data Exchange (ETDEWEB)

    Hull, J. R.; Cansiz, A.

    1999-09-30

    In a PM/HTS bearing, locating a thin-film HTS above a bulk HTS was expected to maintain the large levitation force provided by the bulk with a lower rotational drag provided by the very high current density of the film. For low drag to be achieved, the thin film must shield the bulk from inhomogeneous magnetic fields. Measurement of rotational drag of a PM/HTS bearing that used a combination of bulk and film HTS showed that the thin film is not effective in reducing the rotational drag. Subsequent experiments, in which an AC coil was placed above the thin-film HTS and the magnetic field on the other side of the film was measured, showed that the thin film provides good shielding when the coil axis is perpendicular to the film surface but poor shielding when the coil axis is parallel to the surface. This is consistent with the lack of reduction in rotational drag being due to a horizontal magnetic moment of the permanent magnet. The poor shielding with the coil axis parallel to the film surface is attributed to the aspect ratio of the film and the three-dimensional nature of the current flow in the film for this coil orientation.

  8. Microstructural and mechanical characteristics of Ni–Cr thin films

    Energy Technology Data Exchange (ETDEWEB)

    Petley, Vijay [Gas Turbine Research Establishment, DRDO, Bangalore 93 (India); Sathishkumar, S.; Thulasi Raman, K.H.; Rao, G.Mohan [Department of Instrumentation and Applied Physics, IISc, Bangalore 12 (India); Chandrasekhar, U. [Gas Turbine Research Establishment, DRDO, Bangalore 93 (India)

    2015-06-15

    Highlights: • Ni–Cr thin films of varied composition deposited by DC magnetron co-sputtering. • Thin film with Ni–Cr: 80–20 at% composition exhibits most distinct behavior. • The films were tensile tested and exhibited no cracking till the substrate yielding. - Abstract: Ni–Cr alloy thin films have been deposited using magnetron co-sputtering technique at room temperature. Crystal structure was evaluated using GIXRD. Ni–Cr solid solution upto 40 at% of Cr exhibited fcc solid solution of Cr in Ni and beyond that it exhibited bcc solid solution of Ni in Cr. X-ray diffraction analysis shows formation of (1 1 1) fiber texture in fcc and (2 2 0) fiber texture in bcc Ni–Cr thin films. Electron microscopy in both in-plane and transverse direction of the film surface revealed the presence of columnar microstructure for films having Cr upto 40 at%. Mechanical properties of the films are evaluated using nanoindentation. The modulus values increased with increase of Cr at% till the film is fcc. With further increase in Cr at% the modulus values decreased. Ni–Cr film with 20 at% Ni exhibits reduction in modulus and is correlated to the poor crystallization of the film as reflected in XRD analysis. The Ni–Cr thin film with 80 at% Ni and 20 at% Cr exhibited the most distinct columnar structure with highest electrical resistivity, indentation hardness and elastic modulus.

  9. Growth and Characterization of Doped CeO2 Buffers on Ni-W Substrates for Coated Conductors Using Metal Organic Deposition Method

    Institute of Scientific and Technical Information of China (English)

    WANG Yao; ZHOU Lian; YU Zeming; LI Chengshan; LI Jinshan; JIN Lihu; LU Yafen

    2012-01-01

    CeO2 and Ce0 8Mo2O2-d films (M =Mn,Y,Gd,Sin,Nd and La) with (001) preferred orientation have been prepared on biaxially textured Ni-W substrates by metal organic decomposition (MOD) method.The factors influencing the formation of cracks on the surface of these CeO2 and doped CeO2 films on Ni-W substrates were explored by X-ray diffraction (XRD),scanning electron microscopy (SEM) analysis,atomic force microscopy (AFM) and differential scanning calorimetry (DSC).The results indicate that many factors,such as the change of the ionic radii of doping cations,the transformation of crystal structure and the formation of oxygen vacancies in lattices at high annealing temperature,may be related to the formation of cracks on the surface of these films.However,the crack formation shows no dependence on the crystal lattice mismatch degree of the films with Ni-W substrates.Moreover,the suppression of surface cracks is related to the change of intrinsic elasticity of CeO2 film with doping of cations with a larger radius.SEM and AFM investigations of Ce08Mo2O2-d(M =Y,Gd,Sm,Nd and La) films reveal the dense,smooth and crack-free microstructure,and their lattice parameters match well with that of YBCO,illuminating that they are potentially suitable to be as buffer layer,especially as cap layer in multi-layer architecture of buffer layer for coated conductors.

  10. Preparation and performance of CeO2 hollow spheres and nanoparticles

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wenwen; CHEN Donghui

    2016-01-01

    CeO2 hollow spheres were synthesized by polystryrene sphere (PS) templates and CeO2 nanoparticles were prepared by a facile method. The as-obtained products were characterized by scanning electron microscopy (SEM), N2 adsorption-desorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-vis diffuse reflectance spectra. The results showed that the structure of the obtained CeO2 hollow spheres was hollow microsphere with a diameter of 380 nm and the average particle size of CeO2 nanoparticles was about 1700 nm. The two samples' Brunauer-Emmett-Teller (BET) surface area was 67.1 and 37.2 m2/g. The CeO2 hollow spheres had a better performance than nanoparticles at UV-shielding because of higher surface area and the structure of hollow sphere.

  11. Electrochemical determination of dopamine based on electrospun CeO2/Au composite nanofibers

    International Nuclear Information System (INIS)

    An electrochemical method for the detection of dopamine based on a glass carbon electrode modified with electrospun CeO2/Au composite nanofibers was investigated in this article. The CeO2/Au composite nanofibers were prepared by the electrospinning technique and then annealed in air. The CeO2/Au composite nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements. Cyclic voltammetry (CV) showed that the electrospun CeO2/Au composite nanofibers modified carbon glass electrode exhibited an excellent electrocatalytic response to the dopamine (DA). The detection limit (S/N = 3) was as low as 0.056 μM and the sensitivity could reach 127 μA mM−1 cm−2. All these demonstrated that the electrospun CeO2/Au composite nanofibers were good electrocatalyst for the oxidation of dopamine

  12. Synthesis of Mn-doped CeO2 nanorods and their application as humidity sensors

    Indian Academy of Sciences (India)

    C H Hu; C H Xia; F Wang; M Zhou; P F Yin; X Y Han

    2011-08-01

    Mn-doped CeO2 nanorods have been prepared from CeO2 particles through a facile compositehydroxide-mediated (CHM) approach. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The analysis from the X-ray photoelectron spectroscopy indicates that the manganese doped in CeO2 exists as Mn4+. The responses to humidity for static and dynamic testing proved dopingMn into CeO2 can improve the humidity sensitivity. For the sample with Mn% about 1.22, the resistance changes from 375.3 to 2.7M as the relative humidity (RH) increases from 25 to 90%, indicating promising applications of the Mn-doped CeO2 nanorods in environmental monitoring.

  13. Optimized grid design for thin film solar panels

    NARCIS (Netherlands)

    Deelen, J. van; Klerk, L.; Barink, M.

    2014-01-01

    There is a gap in efficiency between record thin film cells and mass produced thin film solar panels. In this paper we quantify the effect of monolithic integration on power output for various configurations by modeling and present metallization as a way to improve efficiency of solar panels. Grid d

  14. Eutectic bonds on wafer scale by thin film multilayers

    Science.gov (United States)

    Christensen, Carsten; Bouwstra, Siebe

    1996-09-01

    The use of gold based thin film multilayer systems for forming eutectic bonds on wafer scale is investigated and preliminary results will be presented. On polished 4 inch wafers different multilayer systems are developed using thin film techniques and bonded afterwards under reactive atmospheres and different bonding temperatures and forces. Pull tests are performed to extract the bonding strengths.

  15. Structural And Optical Properties Of VOx Thin Films

    OpenAIRE

    Schneider K.

    2015-01-01

    VOx thin films were deposited on Corning glass, fused silica and Ti foils by means of rf reactive sputtering from a metallic vanadium target. Argon-oxygen gas mixtures of different compositions controlled by the flow rates were used for sputtering. Influence of the oxygen partial pressure in the sputtering chamber on the structural and optical properties of thin films has been investigated.

  16. Mixed-valence metal oxide nanoparticles as electrochemical half-cells: substituting the Ag/AgCl of reference electrodes by CeO(2-x) nanoparticles.

    Science.gov (United States)

    Nagarale, Rajaram K; Hoss, Udo; Heller, Adam

    2012-12-26

    Cations of mixed valence at surfaces of metal oxide nanoparticles constitute electrochemical half-cells, with potentials intermediate between those of the dissolved cations and those in the solid. When only cations at surfaces of the particles are electrochemically active, the ratio of electrochemically active/all cations is ~0.1 for 15 nm diameter CeO(2-x) particles. CeO(2-x) nanoparticle-loaded hydrogel films on printed carbon and on sputtered gold constitute reference electrodes having a redox potential similar to that of Ag/AgCl in physiological (0.14 M) saline solutions. In vitro the characteristics of potentially subcutaneously implantable glucose monitoring sensors made with CeO(2-x) nanoparticle reference electrodes are undistinguishable from those of sensors made with Ag/AgCl reference electrodes. Cerium is 900 times more abundant than silver, and commercially produced CeO(2-x) nanoparticle solutions are available at prices well below those of the Ag/AgCl pastes used in the annual manufacture of ~10(9) reference electrodes of glucose monitoring strips for diabetes management. PMID:23171288

  17. Development of artificial surface layers for thin film cathode materials

    OpenAIRE

    Carrillo Solano, Mercedes Alicia

    2016-01-01

    The present work was based on the investigation of different thin film components of Li ion batteries. A first part was dedicated to the deposition of cathodes in thin film form of a known material, LiCoO2, and an alternative one, Li(NiMnCo)O2 employing physical vapor deposition (PVD) and chemical vapor deposition (CVD), respectively. A second part was focused on the cathode-electrolyte interface for three case studies: 1) as deposited LiCoO2 cathode thin film, 2) ZrO2 coated LiCoO2 thin...

  18. Effect of film thickness and texture morphology on the physical properties of lead sulfide thin films

    Science.gov (United States)

    Azadi Motlagh, Z.; Azim Araghi, M. E.

    2016-02-01

    Lead sulfide (PbS) thin films were prepared onto ultra-clean quartz substrate by the electron beam gun (EBG) evaporation method. The thicknesses of the thin films were 50, 100, 150 and 200 nm. They were annealed at 423 K for 2 h. Field emission scanning electron microscopy (FESEM) images of the thin films showed their texture morphology at the surface of the quartz substrate. X-ray diffraction (XRD) patterns of the thin films showed that they have a cubic phase and rock-salt structure after annealing. The average crystallite size for the thin films was in the range of 32-100 nm. Optical measurements confirmed that crystalline thin films have a direct band gap that increases by decreasing the film thickness. This blue shift of the band gap of thin films compared to the bulk structure can be attributed to the quantum confinement effects in the nanoparticles. A decrease in conductivity by increasing the temperature confirmed the positive temperature coefficient of resistance in the thin films that showed the dominant conduction mechanism is via a band-like transition. The density of localized states at the Fermi level increases by increasing the film thickness. Current-voltage behavior of the thin films showed an increase in both dark current and photocurrent by increasing the crystallite size which is discussed, based on the presence of trap states and barriers in nanostructures.

  19. Effect of film thickness and texture morphology on the physical properties of lead sulfide thin films

    International Nuclear Information System (INIS)

    Lead sulfide (PbS) thin films were prepared onto ultra-clean quartz substrate by the electron beam gun (EBG) evaporation method. The thicknesses of the thin films were 50, 100, 150 and 200 nm. They were annealed at 423 K for 2 h. Field emission scanning electron microscopy (FESEM) images of the thin films showed their texture morphology at the surface of the quartz substrate. X-ray diffraction (XRD) patterns of the thin films showed that they have a cubic phase and rock-salt structure after annealing. The average crystallite size for the thin films was in the range of 32–100 nm. Optical measurements confirmed that crystalline thin films have a direct band gap that increases by decreasing the film thickness. This blue shift of the band gap of thin films compared to the bulk structure can be attributed to the quantum confinement effects in the nanoparticles. A decrease in conductivity by increasing the temperature confirmed the positive temperature coefficient of resistance in the thin films that showed the dominant conduction mechanism is via a band-like transition. The density of localized states at the Fermi level increases by increasing the film thickness. Current–voltage behavior of the thin films showed an increase in both dark current and photocurrent by increasing the crystallite size which is discussed, based on the presence of trap states and barriers in nanostructures. (paper)

  20. Nanocoatings and ultra-thin films technologies and applications

    CERN Document Server

    Tiginyanu, Ion

    2011-01-01

    Gives a comprehensive account of the developments of nanocoatings and ultra-thin films. This book covers the fundamentals, processes of deposition and characterisation of nanocoatings, as well as the applications. It is suitable for the glass and glazing, automotive, electronics, aerospace, construction and biomedical industries in particular.$bCoatings are used for a wide range of applications, from anti-fogging coatings for glass through to corrosion control in the aerospace and automotive industries. Nanocoatings and ultra-thin films provides an up-to-date review of the fundamentals, processes of deposition, characterisation and applications of nanocoatings. Part one covers technologies used in the creation and analysis of thin films, including chapters on current and advanced coating technologies in industry, nanostructured thin films from amphiphilic molecules, chemical and physical vapour deposition methods and methods for analysing nanocoatings and ultra-thin films. Part two focuses on the applications...

  1. Thin films and coatings toughening and toughness characterization

    CERN Document Server

    Zhang, Sam

    2015-01-01

    Thin Films and Coatings: Toughening and Toughness Characterization captures the latest developments in the toughening of hard coatings and in the measurement of the toughness of thin films and coatings. Featuring chapters contributed by experts from Australia, China, Czech Republic, Poland, Singapore, Spain, and the United Kingdom, this first-of-its-kind book:Presents the current status of hard-yet-tough ceramic coatingsReviews various toughness evaluation methods for films and hard coatingsExplores the toughness and toughening mechanisms of porous thin films and laser-treated surfacesExamines

  2. Preface: Advanced Thin Film Developments and Nano Structures

    Institute of Scientific and Technical Information of China (English)

    Ray Y.Lin

    2005-01-01

    @@ In this special issue, we invited a few leading materials researchers to present topics in thin films, coatings, and nano structures. Readers will find most recent developments in topics, including recent advances in hard, tough, and low friction nanocomposite coatings; thin films for coating nanomaterials; electroless plating of silver thin films on porous Al2O3 substrate; CrN/Nano Cr interlayer coatings; nano-structured carbide derived carbon (CDC) films and their tribology; predicting interdiffusion in high-temperature coatings; gallium-catalyzed silica nanowire growth; and corrosion protection properties of organofunctional silanes. Authors are from both national laboratories and academia.

  3. Electrochemical Intercalation of Sodium into Silicon Thin Film

    Institute of Scientific and Technical Information of China (English)

    Dong-Yeon Kim; Hyo-Jun Ahn; Gyu-Bong Cho; Jong-Seon Kim; Ho-Suk Ryu; Ki-Won Kim; Jou-Hyeon Ahn; Won-Cheol Shin

    2008-01-01

    In order to investigate the possibility of Si thin film as an anode for Na battery, we studied the electrochemical intercalation of sodium into the Si film. Amorphous Si thin film electrode was prepared using DC magnetron sputtering. Sodium ion could intercalate into Si thin film upto Na0.52Si, i.e. 530mAh · g-1-Si. The first discharge capacity was 80mAh.·g-1-Si, which meant reversible amount of sodium intercalation. The discharge capacity slightly decreased to 70mAh · g-1-Si after 10 cycles.

  4. A versatile platform for magnetostriction measurements in thin films

    Science.gov (United States)

    Pernpeintner, M.; Holländer, R. B.; Seitner, M. J.; Weig, E. M.; Gross, R.; Goennenwein, S. T. B.; Huebl, H.

    2016-03-01

    We present a versatile nanomechanical sensing platform for the investigation of magnetostriction in thin films. It is based on a doubly clamped silicon nitride nanobeam resonator covered with a thin magnetostrictive film. Changing the magnetization direction within the film plane by an applied magnetic field generates a magnetoelastic stress and thus changes the resonance frequency of the nanobeam. A measurement of the resulting resonance frequency shift, e.g., by optical interferometry, allows to quantitatively determine the magnetostriction constants of the thin film. In a proof-of-principle experiment, we determine the magnetostriction constants of a 10 nm thick polycrystalline cobalt film, showing very good agreement with literature values. The presented technique aims, in particular, for the precise measurement of magnetostriction in a variety of (conducting and insulating) thin films, which can be deposited by, e.g., electron beam deposition, thermal evaporation, or sputtering.

  5. Investigation of ferromagnetism in oxygen deficient hafnium oxide thin films

    International Nuclear Information System (INIS)

    Oxygen deficient thin films of hafnium oxide were grown on single crystal r-cut and c-cut sapphire by reactive molecular beam epitaxy. RF-activated oxygen was used for the in situ oxidation of hafnium oxide thin films. Oxidation conditions were varied substantially in order to create oxygen deficiency in hafnium oxide films intentionally. The films were characterized by X-ray and magnetic measurements. X-ray diffraction studies show an increase in lattice parameter with increasing oxygen deficiency. Oxygen deficient hafnium oxide thin films also showed a decreasing bandgap with increase in oxygen deficiency. The magnetisation studies carried out with SQUID did not show any sign of ferromagnetism in the whole oxygen deficiency range. X-ray magnetic circular dichroism measurements also confirmed the absence of ferromagnetism in oxygen deficient hafnium oxide thin films

  6. Characterization of reliability of printed indium tin oxide thin films.

    Science.gov (United States)

    Hong, Sung-Jei; Kim, Jong-Woong; Jung, Seung-Boo

    2013-11-01

    Recently, decreasing the amount of indium (In) element in the indium tin oxide (ITO) used for transparent conductive oxide (TCO) thin film has become necessary for cost reduction. One possible approach to this problem is using printed ITO thin film instead of sputtered. Previous studies showed potential for printed ITO thin films as the TCO layer. However, nothing has been reported on the reliability of printed ITO thin films. Therefore, in this study, the reliability of printed ITO thin films was characterized. ITO nanoparticle ink was fabricated and printed onto a glass substrate followed by heating at 400 degrees C. After measurement of the initial values of sheet resistance and optical transmittance of the printed ITO thin films, their reliabilities were characterized with an isothermal-isohumidity test for 500 hours at 85 degrees C and 85% RH, a thermal shock test for 1,000 cycles between 125 degrees C and -40 degrees C, and a high temperature storage test for 500 hours at 125 degrees C. The same properties were investigated after the tests. Printed ITO thin films showed stable properties despite extremely thermal and humid conditions. Sheet resistances of the printed ITO thin films changed slightly from 435 omega/square to 735 omega/square 507 omega/square and 442 omega/square after the tests, respectively. Optical transmittances of the printed ITO thin films were slightly changed from 84.74% to 81.86%, 88.03% and 88.26% after the tests, respectively. These test results suggest the stability of printed ITO thin film despite extreme environments. PMID:24245331

  7. Altering properties of cerium oxide thin films by Rh doping

    International Nuclear Information System (INIS)

    Highlights: • Thin films of ceria doped by rhodium deposited by RF magnetron sputtering. • Concentration of rhodium has great impact on properties of Rh–CeOx thin films. • Intensive oxygen migration in films with low concentration of rhodium. • Oxygen migration suppressed in films with high amount of Rh dopants. - Abstract: Ceria containing highly dispersed ions of rhodium is a promising material for catalytic applications. The Rh–CeOx thin films with different concentrations of rhodium were deposited by RF magnetron sputtering and were studied by soft and hard X-ray photoelectron spectroscopies, Temperature programmed reaction and X-ray powder diffraction techniques. The sputtered films consist of rhodium–cerium mixed oxide where cerium exhibits a mixed valency of Ce4+ and Ce3+ and rhodium occurs in two oxidation states, Rh3+ and Rhn+. We show that the concentration of rhodium has a great influence on the chemical composition, structure and reducibility of the Rh–CeOx thin films. The films with low concentrations of rhodium are polycrystalline, while the films with higher amount of Rh dopants are amorphous. The morphology of the films strongly influences the mobility of oxygen in the material. Therefore, varying the concentration of rhodium in Rh–CeOx thin films leads to preparing materials with different properties

  8. Slippage and Nanorheology of Thin Liquid Polymer Films

    OpenAIRE

    Bäumchen, Oliver; Fetzer, Renate; Klos, Mischa; Lessel, Matthias; Marquant, Ludovic; Hähl, Hendrik; Jacobs, Karin

    2012-01-01

    Thin liquid films on surfaces are part of our everyday life, they serve e.g. as coatings or lubricants. The stability of a thin layer is governed by interfacial forces, described by the effective interface potential, and has been subject of many studies in the last decades. In recent years, the dynamics of thin liquid films came into focus since results on the reduction of the glass transition temperature raised new questions on the behavior of especially polymeric liquids in confined geometr...

  9. Production of selective membranes using plasma deposited nanochanneled thin films

    OpenAIRE

    Rodrigo Amorim Motta Carvalho; Alexsander Tressino Carvalho; Maria Lúcia Pereira da Silva; Nicole Raymond Demarquette

    2006-01-01

    The hydrolization of thin films obtained by tetraethoxysilane plasma polymerization results in the formation of a nanochanneled silicone like structure that could be useful for the production of selective membranes. Therefore, the aim of this work is to test the permeation properties of hydrolyzed thin films. The films were tested for: 1) permeation of polar organic compounds and/or water in gaseous phase and 2) permeation of salt in liquid phase. The efficiency of permeation was tested using...

  10. On the nature of shear thinning in nanoscopically confined films

    OpenAIRE

    Manias, E; Bitsanis, I.; Hadziioannou, G.; Brinke, G. ten

    1996-01-01

    Non-Equilibrium Molecular Dynamics (NEMD) computer simulations were employed to study films in nanometer confinements under shear. Focusing on the response of the viscosity, we found that nearly all the shear thinning takes place inside the solid-oligomer interface and that the adsorbed layers are more viscous than the middle part of the films. Moreover, the shear thinning inside the interfacial area is determined by the wall affinity and is largely insensitive to changes of the film thicknes...

  11. Strain and composition effects in epitaxial PZT thin films

    OpenAIRE

    Steenwelle, R.J.A.

    2012-01-01

    The deposition of perovskite oxide thin films on silicon wafers is attracting great interest, since it promises the possibility of mass-production of thin film devices with functional mechanisms such as piezoelectricity, ferroelectricity, superconductivity, magnetism, and dielectricity. Piezoelectric Micro Electro Mechanical Systems (PiezoMEMS) using Pb(Zrx,Ti1-x)O3 (PZT) films on silicon are often viewed as forerunner in this trend, with promising applications such as inkjet printheads, piez...

  12. Thin film adhesion by nanoindentation-induced superlayers. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gerberich, William W.; Volinsky, A.A.

    2001-06-01

    This work has analyzed the key variables of indentation tip radius, contact radius, delamination radius, residual stress and superlayer/film/interlayer properties on nanoindentation measurements of adhesion. The goal to connect practical works of adhesion for very thin films to true works of adhesion has been achieved. A review of this work titled ''Interfacial toughness measurements of thin metal films,'' which has been submitted to Acta Materialia, is included.

  13. Synthesis and Characterization of Amorphous Carbide-based Thin Films

    OpenAIRE

    Folkenant, Matilda

    2015-01-01

    In this thesis, research on synthesis, structure and characterization of amorphous carbide-based thin films is presented. Crystalline and nanocomposite carbide films can exhibit properties such as high electrical conductivity, high hardness and low friction and wear. These properties are in many cases structure-related, and thus, within this thesis a special focus is put on how the amorphous structure influences the material properties. Thin films within the Zr-Si-C and Cr-C-based systems hav...

  14. Pulsed laser deposition and characterisation of thin superconducting films

    Energy Technology Data Exchange (ETDEWEB)

    Morone, A. [CNR, zona industriale di Tito Scalo, Potenza (Italy). Istituto per i Materiali Speciali

    1996-09-01

    Same concepts on pulsed laser deposition of thin films will be discussed and same examples of high transition temperature (HTc) BiSrCaCuO (BISCO) and low transition temperature NbN/MgO/NbN multilayers will be presented. X-ray and others characterizations of these films will be reported and discussed. Electrical properties of superconducting thin films will be realized as a function of structural and morphological aspect.

  15. Fabricating Thin-Film High-Temperature Thermoset Resins

    Science.gov (United States)

    Dickerson, G. E.; Long, E. R. J.; Kitts, R., G.

    1982-01-01

    To prepare an epoxy thin film, quantity of uncured epoxy to be cast placed in vacuum oven and heated to melting temperature. Vacuum of about 30 mm Hg is applied to deaerate epoxy charge. Pressure is cycled with each foaming until all air and excess volatiles are revoved. thermoset (cross-linked) resin is cast between thin, flexible, releasing substrate films. Films less than 0.025 mm in thickness are made routinely with this facility.

  16. Recovery Act : Near-Single-Crystalline Photovoltaic Thin Films on Polycrystalline, Flexible Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Venkat Selvamanickam; Alex Freundlich

    2010-11-29

    III-V photovoltaics have exhibited efficiencies above 40%, but have found only a limited use because of the high cost of single crystal substrates. At the other end of the spectrum, polycrystalline and amorphous thin film solar cells offer the advantage of low-cost fabrication, but have not yielded high efficiencies. Our program is based on single-crystalline-like thin film photovoltaics on polycrystalline substrates using biaxially-textured templates made by Ion Beam-Assisted Deposition (IBAD). MgO templates made by IBAD on flexible metal substrate have been successfully used for epitaxial growth of germanium films. In spite of a 4.5% lattice mismatch, heteroepitaxial growth of Ge was achieved on CeO2 that was grown on IBAD MgO template. Room temperature optical bandgap of the Ge films was identified at 0.67 eV indicating minimal residual strain. Refraction index and extinction coefficient values of the Ge films were found to match well with that measured from a reference Ge single crystal. GaAs has been successfully grown epitaxially on Ge on metal substrate by molecular beam epitaxy. RHEED patterns indicate self annihilation of antiphase boundaries and the growth of a single domain GaAs. The GaAs is found to exhibit strong photoluminescence signal and, an existence of a relatively narrow (FWHM~20 meV) band-edge excitons measured in this film indicates a good optoelectronic quality of deposited GaAs. While excellent epitaxial growth has been achieved in GaAs on flexible metal substrates, the defect density of the films as measured by High Resolution X-ray Diffraction and etch pit experiments showed a high value of 5 * 10^8 per cm^2. Cross sectional transmission electron microscopy of the multilayer architecture showed concentration of threading dislocations near the germanium-ceria interface. The defect density was found decrease as the Ge films were made thicker. The defects appear to originate from the MgO layer presumably because of large lattice mismatches

  17. Transferable and flexible thin film devices for engineering applications

    International Nuclear Information System (INIS)

    Thin film devices can be of significance for manufacturing, energy conversion systems, solid state electronics, wireless applications, etc. However, these thin film sensors/devices are normally fabricated on rigid silicon substrates, thus neither flexible nor transferrable for engineering applications. This paper reports an innovative approach to transfer polyimide (PI) embedded thin film devices, which were fabricated on glass, to thin metal foils. Thin film thermocouples (TFTCs) were fabricated on a thin PI film, which was spin coated and cured on a glass substrate. Another layer of PI film was then spin coated again on TFTC/PI and cured to obtain the embedded TFTCs. Assisted by oxygen plasma surface coarsening of the PI film on the glass substrate, the PI embedded TFTC was successfully transferred from the glass substrate to a flexible copper foil. To demonstrate the functionality of the flexible embedded thin film sensors, they were transferred to the sonotrode tip of an ultrasonic metal welding machine for in situ process monitoring. The dynamic temperatures near the sonotrode tip were effectively measured under various ultrasonic vibration amplitudes. This technique of transferring polymer embedded electronic devices onto metal foils yield great potentials for numerous engineering applications. (paper)

  18. Studying of kinetic growth of organic thin films

    Directory of Open Access Journals (Sweden)

    J.P. Weszka

    2009-07-01

    Full Text Available Purpose: of this paper: Studying of growth kinetic of organic thin film prepared by vacuum thermal evaporation technology.Design/methodology/approach: Applying of quartz crystal microbalance to thickness control of organic thin films deposition process.Findings: Results of this issue suggesting that the kinetics of organic thin films is depending of current flowing through the crucible (crucible temperature.Research limitations/implications: Kinetics of vacuum evaporation of thin film is different from that of inorganic thin films during the growth process.Practical implications: The means of connect the quartz crystal microbalance MSV 1843/AB with vacuum chamber, function and means of thickness and deposition rate measuring has been described. This scientific paper include also description of researching results of kinetics of organic and metallic thin film evaporation process by MSV 1843/AB quartz crystal microbalance and verification these results by comparing them with results from other measuring techniques.Originality/value: Controlling thickness of thermally evaporated organic thin film during the film growth process.

  19. Patterns and conformations in molecularly thin films

    Science.gov (United States)

    Basnet, Prem B.

    Molecularly thin films have been a subject of great interest for the last several years because of their large variety of industrial applications ranging from micro-electronics to bio-medicine. Additionally, molecularly thin films can be used as good models for biomembrane and other systems where surfaces are critical. Many different kinds of molecules can make stable films. My research has considered three such molecules: a polymerizable phospholipid, a bent-core molecules, and a polymer. One common theme of these three molecules is chirality. The phospolipid molecules studied here are strongly chiral, which can be due to intrinsically chiral centers on the molecules and also due to chiral conformations. We find that these molecules give rise to chiral patterns. Bent-core molecules are not intrinsically chiral, but individual molecules and groups of molecules can show chiral structures, which can be changed by surface interactions. One major, unconfirmed hypothesis for the polymer conformation at surface is that it forms helices, which would be chiral. Most experiments were carried out at the air/water interface, in what are called Langmuir films. Our major tools for studying these films are Brewster Angle Microscopy (BAM) coupled with the thermodynamic information that can be deduced from surface pressure isotherms. Phospholipids are one of the important constituents of liposomes -- a spherical vesicle com-posed of a bilayer membrane, typically composed of a phospholipid and cholesterol bilayer. The application of liposomes in drug delivery is well-known. Crumpling of vesicles of polymerizable phospholipids has been observed. With BAM, on Langmuir films of such phospholipids, we see novel spiral/target patterns during compression. We have found that both the patterns and the critical pressure at which they formed depend on temperature (below the transition to a i¬‘uid layer). Bent-core liquid crystals, sometimes knows as banana liquid crystals, have drawn

  20. Electrochromism: from oxide thin films to devices

    Science.gov (United States)

    Rougier, A.; Danine, A.; Faure, C.; Buffière, S.

    2014-03-01

    In respect of their adaptability and performance, electrochromic devices, ECDs, which are able to change their optical properties under an applied voltage, have received significant attention. Target applications are multifold both in the visible region (automotive sunroofs, smart windows, ophthalmic lenses, and domestic appliances (oven, fridge…)) and in the infrared region (Satellites Thermal Control, IR furtivity). In our group, focusing on oxide thin films grown preferentially at room temperature, optimization of ECDs performances have been achieved by tuning the microstructure, the stoichiometry and the cationic composition of the various layers. Herein, our approach for optimized ECDs is illustrated through the example of WO3 electrochromic layer in the visible and in the IR domain as well as ZnO based transparent conducting oxide layer. Targeting the field of printed electronics, simplification of the device architecture for low power ECDs is also reported.

  1. Thin Film Femtosecond Laser Damage Competition

    Energy Technology Data Exchange (ETDEWEB)

    Stolz, C J; Ristau, D; Turowski, M; Blaschke, H

    2009-11-14

    In order to determine the current status of thin film laser resistance within the private, academic, and government sectors, a damage competition was started at the 2008 Boulder Damage Symposium. This damage competition allows a direct comparison of the current state of the art of high laser resistance coatings since they are tested using the same damage test setup and the same protocol. In 2009 a high reflector coating was selected at a wavelength of 786 nm at normal incidence at a pulse length of 180 femtoseconds. A double blind test assured sample and submitter anonymity so only a summary of the results are presented here. In addition to the laser resistance results, details of deposition processes, coating materials and layer count, and spectral results will also be shared.

  2. Nanocrystalline silicon thin films for thermoelectric applications

    Science.gov (United States)

    Queen, Daniel; Jugdersuren, Battogtokh; Culberston, Jim; Wang, Qi; Nemeth, William; Metcalf, Tom; Liu, Xiao

    2014-03-01

    Recent advances in thermoelectric materials have come from reductions in thermal conductivity by manipulating both chemical composition and nanostructure to limit the phonon mean free path. However, wide spread applications for some of these materials may be limited due to high raw material and integration costs. In this talk we will discuss our recent results on nanocrystalline silicon thin films deposited by both hot-wire and plasma enhanced chemical vapor deposition where the nanocrystal size and crystalline volume fraction are varied by dilution of the silane precursor gas with hydrogen. Nanocyrstalline silicon is an established material technology used in multijunction amorphous silicon solar cells and has the potential to be a low cost and scalable material for use in thermoelectric devices. This work supported by the Office of Naval Research and the National Research Council.

  3. Transport measurements in overdoped YBCO thin films

    International Nuclear Information System (INIS)

    Temperature dependence of Hall constant RH and longitudinal resistivity ρxx have been measured in Ca-doped YBCO thin films with varying oxygen contents, with emphasis on the overdoped regime. RH vs. T data present a peak near Tc whose height reduces with doping and disappears at optimal doping. Unexpectedly, the peak reappears above optimal doping with a height that increases with doping. A similar behavior was observed in the parameters that fit cot(θH) vs. T to a parabola. They decrease smoothly with increasing doping in the underdoped region and present a peculiar peak in the overdoped region. This behavior might indicate the crossover to a new regime of transport properties in strongly overdoped HTSC. We discuss the possible origin and implications of these results

  4. Transparent Conductive Oxides in Thin Film Photovoltaics

    International Nuclear Information System (INIS)

    This paper show results from the development of transparent conductive oxides (TCO's) on large areas for the use as front electrode in thin film silicon solar modules. It is focused on two types of zinc oxide, which are cheap to produce and scalable to a substrate size up to 6 m2. Low pressure CVD with temperatures below 200°C can be used for the deposition of boron doped ZnO with a native surface texture for good light scattering, while sputtered aluminum doped ZnO needs a post deposition treatment in an acid bath for a rough surface. The paper presents optical and electrical characterization of large area samples, and also results about long term stability of the ZnO samples with respect to the so called TCO corrosion

  5. Nonlinear optics of astaxanthin thin films

    Science.gov (United States)

    Esser, A.; Fisch, Herbert; Haas, Karl-Heinz; Haedicke, E.; Paust, J.; Schrof, Wolfgang; Ticktin, Anton

    1993-02-01

    Carotinoids exhibit large nonlinear optical properties due to their extended (pi) -electron system. Compared to other polyenes which show a broad distribution of conjugation lengths, carotinoids exhibit a well defined molecular structure, i.e. a well defined conjugation length. Therefore the carotinoid molecules can serve as model compounds to study the relationship between structure and nonlinear optical properties. In this paper the synthesis of four astaxanthins with C-numbers ranging from 30 to 60, their preparation into thin films, wavelength dispersive Third Harmonic Generation (THG) measurements and some molecular modelling calculations will be presented. Resonant (chi) (3) values reach 1.2(DOT)10-10 esu for C60 astaxanthin. In the nonresonant regime a figure of merit (chi) (3)/(alpha) of several 10-13 esu-cm is demonstrated.

  6. Surfactant Spreading on Thin Viscous Fluid Films

    Science.gov (United States)

    Bonilla, Caitlyn; Leslie, Nathaniel; Liu, Jeanette; Sinclair, Dina; Levy, Rachel

    2014-11-01

    We examine the spreading of insoluble lipids on a viscous Newtonian thin fluid film. This spreading can be modeled as two coupled nonlinear fourth-order partial differential equations, though inconsistencies between the timescale of experiments and simulations have been reported in recent research. In simulations, we replace traditional models for the equation of state relating surfactant concentration to surface tension with an empirical equation of state. Isotherms collected via a Langmuir-Pockels scale provide data for the equation of state. We compare the timescale of simulation results to measurements of the fluorescently tagged lipid (NBD-PC) spreading as well as the height profile, captured with laser profilometry. Research supported by NSF-DMS-FRG 9068154, RCSA-CCS-19788, HHMI.

  7. Stabilized thin film heterostructure for electrochemical applications

    DEFF Research Database (Denmark)

    2015-01-01

    The invention provides a method for the formation of a thin film multi-layered heterostructure upon a substrate, said method comprising the steps of: a. providing a substrate; b. depositing a buffer layer upon said substrate, said buffer layer being a layer of stable ionic conductor (B); c....... depositing a layer A upon said buffer layer, said layer A being a layer of fast ionic conductor (A), said layer A having a thickness (tA) of 20 nm or less; d. depositing a layer B upon said layer A, said layer B being a layer of stable ionic conductor (B), said layer B having a thickness (tB ) of 150 nm or...

  8. Structure and Microstructure of Ni-Mn-Ga thin films

    OpenAIRE

    A. Annadurai

    2013-01-01

    Ni-Mn-Ga thin films were dc magnetron sputter deposited onto well cleaned substrates of si(100) and glass in high pure argon atmosphere of pressure of 0.01 mbar using NiMnGa alloy targets prepared in ourlaboratory by vacuum induction melting technique. Pristine thin films were investigated. Crystal structure of the films was studied using x-ray diffraction (XRD) technique. Microstructure of the films was investigated using scanning electron microscope (SEM). XRD reveals that the films on glas...

  9. Structural, electrical and thermoelectrical analysis of nickel sulphide thin films

    Science.gov (United States)

    Chate, P. A.; Sathe, D. J.

    2016-06-01

    A dip method is employed for the deposition of NiS2 thin film at room temperature. Nickel sulphate, succinic acid and thiourea were used as the source materials. The X-ray diffraction analysis shows that the film samples are cubic phase. The specific electrical conductivity of the film was found to be 3.16 × 10-6 (Ω cm)-1. The films show high absorption, and band gap energy value was found to be 1.37 eV. The temperature dependence of an electrical conductivity, thermoelectrical power, carrier density and carrier mobility for NiS2 thin films has been examined.

  10. Fluorine doped vanadium dioxide thin films for smart windows

    Energy Technology Data Exchange (ETDEWEB)

    Kiri, Pragna [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London, WC1H 0AJ (United Kingdom); Warwick, Michael E.A. [UCL Energy Institute, Central House, 14 Upper Woburn Place, London, WC1H 0HY (United Kingdom); Ridley, Ian [Bartlett School of Graduate Studies, University College London, Wates House, 22 Gordon Street, WC1H 0QB, London (United Kingdom); Binions, Russell, E-mail: r.binions@ucl.ac.uk [Department of Chemistry, University College London, Christopher Ingold Laboratories, 20 Gordon Street, London, WC1H 0AJ (United Kingdom)

    2011-12-01

    Thermochromic fluorine doped thin films of vanadium dioxide were deposited from the aerosol assisted chemical vapour deposition reaction of vanadyl acetylacetonate, ethanol and trifluoroacetic acid on glass substrates. The films were characterised with scanning electron microscopy, variable temperature Raman spectroscopy and variable temperature UV/Vis spectroscopy. The incorporation of fluorine in the films led to an increase in the visible transmittance of the films whilst retaining the thermochromic properties. This approach shows promise for improving the aesthetic properties of vanadium dioxide thin films.

  11. Isotopic exchange between gaseous hydrogen and scandium dideuteride thin films

    International Nuclear Information System (INIS)

    As part of a study to understand the long-term storage effects on scandium hydride thin films, an experiment has been conducted in which scandium dideuteride thin films were exposed to a hydrogen environment for various periods of time at ambient temperature. The resulting films were analysed using neutron reflectivity using the surface profile analysis reflectometer (SPEAR) at the Los Alamos Neutron Science Center. Using neutron reflectivity and taking advantage of the large difference in the neutron scattering lengths of hydrogen and deuterium, the resulting changes in the film composition due to isotopic exchange and diffusion were observed as a function of the film depth. (orig.)

  12. Plasma synthesis of photocatalytic TiO x thin films

    Science.gov (United States)

    Sirghi, L.

    2016-06-01

    The development of efficient photocatalytic materials is promising technology for sustainable and green energy production, fabrication of self-cleaning, bactericidal, and super hydrophilic surfaces, CO2 photoreduction, and decomposition of toxic pollutants in air and water. Semiconductors with good photocatalytic activity have been known for four decades and they are regarded as promising candidates for these new technologies. Low-pressure discharge plasma is one of the most versatile technologies being used for the deposition of photocatalytic semiconductor thin films. This article reviews the main results obtained by the author in using low-pressure plasma for synthesis of TiO x thin films with applications in photocatalysis. Titanium dioxide thin films were obtained by radio frequency magnetron sputtering deposition, plasma enhanced chemical vapour deposition, and high power impulse magnetron sputtering deposition. The effects of the plasma deposition method, plasma parameters, film thickness and substrate on the film structure, chemical composition and photocatalytic activity are investigated. The photocatalytic activity of plasma synthesised TiO x thin films was estimated by UV light induced hydrophilicity. Measurements of photocurrent decay in TiO x thin films in vacuum and air showed that the photocatalytic activity is closely connected to the production, recombination and availability for surface reactions of photo-generated charge carriers. The photocatalytic activity of TiO x thin films was investigated at nanoscale by atomic force microscopy. Microscopic regions of different hydrophilicity on UV light irradiated films are discriminated by AFM atomic force microscopy measurements of adhesion and friction force.

  13. Thin film characterization by resonantly excited internal standing waves

    Energy Technology Data Exchange (ETDEWEB)

    Di Fonzio, S. [SINCROTRONE TRIESTE, Trieste (Italy)

    1996-09-01

    This contribution describes how a standing wave excited in a thin film can be used for the characterization of the properties of the film. By means of grazing incidence X-ray reflectometry one can deduce the total film thickness. On the other hand in making use of a strong resonance effect in the electric field intensity distribution inside a thin film on a bulk substrate one can learn more about the internal structure of the film. The profile of the internal standing wave is proven by diffraction experiments. The most appropriate non-destructive technique for the subsequent thin film characterization is angularly dependent X-ray fluorescence analysis. The existence of the resonance makes it a powerful tool for the detection of impurities and of ultra-thin maker layers, for which the position can be determined with very high precision (about 1% of the total film thickness). This latter aspect will be discussed here on samples which had a thin Ti marker layer at different positions in a carbon film. Due to the resonance enhancement it was still possible to perform these experiments with a standard laboratory x-ray tube and with standard laboratory tool for marker or impurity detection in thin films.

  14. Room temperature ferromagnetism in pristine MgO thin films

    International Nuclear Information System (INIS)

    Robust ferromagnetic ordering at, and well above room temperature is observed in pure transparent MgO thin films (3 is measured on a 170 nm thick film. The films above 500 nm are found to be diamagnetic. Ab initio calculations suggest that the ferromagnetism is mediated by cation vacancies.

  15. Effective dielectric and piezoelectric constants of polycrystalline ferroelectric thin films

    International Nuclear Information System (INIS)

    The averaged dielectric, piezoelectric and elastic constants of polycrystalline thin films of barium and lead titanates are calculated theoretically through the effective medium method, accounting for piezoelectric interactions between crystallites. The film with the c- or a-type crystal texture, formed through mechanical interaction with the sublayer in the process of the film transition into ferroelectric state by cooling the heterostructure, are considered

  16. Quantum-well-induced ferromagnetism in thin films

    DEFF Research Database (Denmark)

    Niklasson, A.M.N.; Mirbt, S.; Skriver, Hans Lomholt;

    1997-01-01

    We have used a first-principles Green's-function technique to investigate the magnetic properties of thin films of Rh, Pd, and Pt deposited on a fee Ag (001) substrate. We find that the magnetic moment of the film is periodically suppressed and enhanced as a function of film thickness. The...

  17. Surface excitations in thin helium films on silica aerogel

    CERN Document Server

    Lauter, H J; Puchkov, A V; Skomorokhov, A; Godfrin, H; Klier, J; Leiderer, P

    2002-01-01

    First measurements are reported on pure surface excitations in thin superfluid sup 4 He films on silica aerogel. The ripplon dispersion curve is found to be the same for helium on graphite and silica aerogel substrates. However, the layered roton line width in helium films on aerogel shows a pronounced broadening with respect to that found in helium films on graphite. (orig.)

  18. Surface excitations in thin helium films on silica aerogel

    International Nuclear Information System (INIS)

    First measurements are reported on pure surface excitations in thin superfluid 4He films on silica aerogel. The ripplon dispersion curve is found to be the same for helium on graphite and silica aerogel substrates. However, the layered roton line width in helium films on aerogel shows a pronounced broadening with respect to that found in helium films on graphite. (orig.)

  19. Materials availability for thin film solar cells

    Science.gov (United States)

    Makita, Yunosuke

    1997-04-01

    Materials availability is one of the most important factors when we consider the mass-production of next generation photovoltaic devices. "In (indium)" is a vital element to produce high efficient thin film solar cells such as InP and CuIn(Ga)Se2 but its lifetime as a natural resource is suggested to be of order of 10˜15 years. The lifetime of a specific natural resource as an element to produce useful device substances is directly related with its abundance in the earth's crust, consumption rate and recycling rate (if recycling is economically meaningful). The chemical elements having long lifetime as a natural resource are those existing in the atmosphere such as N (nitrogen) and O (oxygen); the rich elements in the earth's crust such as Si, Ca, Sr and Ba; the mass-used metals such as Fe (iron), Al (aluminum) and Cu (copper) that reached the stage of large-scale recycling. We here propose a new paradigm of semiconductor material-science for the future generation thin film solar cells in which only abundant chemical elements are used. It is important to remark that these abundant chemical elements are normally not toxic and are fairly friendly to the environment. β-FeSi2 is composed of two most abundant and nontoxic chemical elements. This material is one of the most promising device materials for future generation energy devices (solar cells and thermoelectric device that is most efficient at temperature range of 700-900 °C). One should remind of the versatility of β-FeSi2 that this material can be used not only as energy devices but also as photodetector, light emitting diode and/or laser diode at the wavelength of 1.5 μm that can be monolithically integrated on Si substrates due to the relatively small lattice mismatch.

  20. Laser induced vibration of a thin soap film.

    OpenAIRE

    Emile, Olivier; Emile, Janine

    2014-01-01

    We report on the vibration of a thin soap film based on the optical radiation pressure force. The modulated low power laser induces a counter gravity flow in a vertical free standing draining film. The thickness of the soap film is then higher in the upper region than in the lower region of the film. Moreover, the lifetime of the film is dramatically increased by a factor of 2. Since the laser beam only acts mechanically on the film interfaces, such a film can be implemented in an optofluidic...

  1. Nonlinear generation of vorticity in thin smectic films

    CERN Document Server

    Parfenyev, V M; Lebedev, V V

    2015-01-01

    We analyze a solenoidal motion in a vertically vibrated freely suspended thin smectic film. We demonstrate analytically that transverse oscillations of the film generate two-dimensional vortices in the plane of the film owing to hydrodynamic nonlinearity. An explicit expression for the vorticity of the in-plane film motion in terms of the film displacement is obtained. The air around the film is proven to play a crucial role, since it changes the dispersion relation of transverse oscillations and transmits viscous stresses to the film, modifying its bending motion. We propose possible experimental observations enabling to check our predictions.

  2. Radiation processing of sago hydrogel thin film

    International Nuclear Information System (INIS)

    Research study in the production of sago hydrogel sheet for wound dressings application by radiation process using high-energy electron beam machine (3 MeV) has been well established at MINT. However, producing thin film sago hydrogel is another potential usage of this sago hydrogel. The research activity is to look upon the possibility of utilize low-energy electron beam, Curetron (200 keV) for this purpose. The studies are concentrate on the radiation parameters such as beam current, voltage and dosage, thickness of sago hydrogel and density of polyvinyl alcohol solution for comparison purpose. The studies reveal that crosslinking of sago hydrogel depend on thickness of the material exposed to electron beam i.e. thin sample gives higher degree of crosslink compared to thicker sample, at specific dosage and beam current. Above 0.5 mm thickness, the sago hydrogel cannot be crosslinked by low energy electron beam. The results also show that for Curetron 8 mA is the optimum beam current for effective crosslinking process of sago hydrogel. The penetration of electron beam by Curetron depends on density, based on the gel fraction of PVA crosslink where 20% PVA has higher gel fraction than 25% PVA at specific dosage and thickness of sample. From the study using high-energy electron beam machine (3 MeV), the degree of crosslink reduced with increasing thickness of sago hydrogel for the voltage less than 0.75 MeV. (author)

  3. Transparent conducting thin films for spacecraft applications

    Science.gov (United States)

    Perez-Davis, Marla E.; Malave-Sanabria, Tania; Hambourger, Paul; Rutledge, Sharon K.; Roig, David; Degroh, Kim K.; Hung, Ching-Cheh

    1994-01-01

    Transparent conductive thin films are required for a variety of optoelectronic applications: automotive and aircraft windows, and solar cells for space applications. Transparent conductive coatings of indium-tin-oxide (ITO)-magnesium fluoride (MgF2) and aluminum doped zinc oxide (AZO) at several dopant levels are investigated for electrical resistivity (sheet resistance), carrier concentration, optical properties, and atomic oxygen durability. The sheet resistance values of ITO-MgF2 range from 10(exp 2) to 10(exp 11) ohms/square, with transmittance of 75 to 86 percent. The AZO films sheet resistances range from 10(exp 7) to 10(exp 11) ohms/square with transmittances from 84 to 91 percent. It was found that in general, with respect to the optical properties, the zinc oxide (ZnO), AZO, and the high MgF2 content ITO-MgF2 samples, were all durable to atomic oxygen plasma, while the low MgF2 content of ITO-MgF2 samples were not durable to atomic oxygen plasma exposure.

  4. Josephson junction in a thin film

    International Nuclear Information System (INIS)

    The phase difference φ(y) for a vortex at a line Josephson junction in a thin film attenuates at large distances as a power law, unlike the case of a bulk junction where it approaches exponentially the constant values at infinities. The field of a Josephson vortex is a superposition of fields of standard Pearl vortices distributed along the junction with the line density φ'(y)/2π. We study the integral equation for φ(y) and show that the phase is sensitive to the ratio l/Λ, where l=λJ2/λL, Λ=2λL2/d, λL, and λJ are the London and Josephson penetration depths, and d is the film thickness. For l2=λJ2λL/d/y2; i.e., it diverges as T→Tc. For l>>Λ, both the core and the tail have nearly the same characteristic length lΛ

  5. Two approaches for enhancing the hydrogenation properties of palladium: Metal nanoparticle and thin film over layers

    Indian Academy of Sciences (India)

    Manika Khanuja; B R Mehta; S M Shivaprasad

    2008-11-01

    In the present study, two approaches have been used for enhancing the hydrogenation properties of Pd. In the first approach, metal thin film (Cu, Ag) has been deposited over Pd and hydrogenation properties of bimetal layer Cu (thin film)/Pd(thin film) and Ag(thin film)/Pd(thin film) have been studied. In the second approach, Ag metal nanoparticles have been deposited over Pd and hydrogenation properties of Ag (nanoparticle)/Pd (thin film) have been studied and compared with Ag(thin film)/Pd(thin film) bimetal layer system. The observed hydrogen sensing response is stable and reversible over a number of hydrogen loading and deloading cycles in both bimetallic systems. Alloying between Ag and Pd is suppressed in case of Ag(nanoparticle)/Pd(thin film) bimetallic layer on annealing as compared to Ag (thin film)/Pd(thin film).

  6. Bio diesel synthesis from pongamia pinnata oil over modified CeO2 catalysts

    International Nuclear Information System (INIS)

    This study investigates the use of CeO2, ZrO2, Mg O and CeO2-ZrO2, CeO2-Mg O, CeO2-ZrO2-Mg O mixed oxides as solid base catalysts for the transesterification of Pongamia pinnata oil with methanol to produce bio diesel. SO42-/CeO2 and SO42-/CeO2-ZrO2 were also prepared and used as solid acid catalysts for esterification of Pongamia pinnata oil (P-oil) to reduce the % of free fatty acid (FFA) in P-oil. The oxide catalysts were prepared by an incipient wetness impregnation method and characterized by techniques such as NH3-Tpd for surface acidity, CO2-Tpd for surface basicity and powder X-ray diffraction for crystallinity. The effect of nature of the catalyst, methanol to P-oil molar ratio and reaction time in esterification as well as in transesterification was investigated. The catalytic materials were reactive d and reused for five reaction cycles and the results showed that the ceria based catalysts have reasonably good reusability both in esterification and transesterification reaction. The test results also revealed that the CeO2-ZrO2 modified with Mg O could have potential for use in the large scale bio diesel production. (Author)

  7. Effects of Surfactants on the Performance of CeO2 Humidity Sensor

    Directory of Open Access Journals (Sweden)

    Chunjie Wang

    2014-01-01

    Full Text Available Nanosized CeO2 powders were synthesized via hydrothermal method with different types of surfactants (polyethylene glycol (PEG, cetyltrimethylammonium bromide (CTAB, and sodium dodecylbenzenesulfonate (SDBS. X-ray diffraction, Raman spectroscopy, and transmission electron microscopy were utilized to characterize the phase structures and morphologies of the products. The sample with CTAB as surfactant (CeO2-C has the largest specific surface area and the smallest particle size among these three samples. The humidity sensor fabricated by CeO2-C shows higher performance than those used CeO2-P and CeO2-S. The impedance of the CeO2-C sensor decreases by about five orders of magnitude with relative humidity (RH changing from 15.7 to 95%. The response and recovery time are 7 and 7 s, respectively. These results indicate that the performance of CeO2 humidity sensors can be improved effectively by the addition of cationic surfactant.

  8. Photocatalytic and antibacterial properties of phytosynthesized CeO2 NPs using Moringa oleifera peel extract.

    Science.gov (United States)

    Surendra, T V; Roopan, Selvaraj Mohana

    2016-08-01

    Biosynthetic methods are alternative approaches which are much safer than the normal techniques (physical and chemical) used for the methods for synthesis of metal nanoparticles. The benefits are sample as it is economic and environment friendly. Herein present investigation, we have reported a microwave mediated eco-friendly synthetic approach for preparing cerium oxide (CeO2) nanoparticles. Here, we used Moringa oleifera peel as the stabilizing and reducing agent towards synthesize of Ce2O NPs via microwave irradiation. The NPs were further characterized using UV-Vis, FT-IR, XRD and HR-TEM techniques. The FTIR analysis confirmed the phytochemical involvement in NPs stabilization. The crystallinity of CeO2 nanoparticles are well demonstrated through X-ray Diffraction and HR-TEM. The TEM images reveal the spherical shape of the CeO2 NPs having an average size of 45nm. Additionally, these CeO2 NPs were used successfully as a catalyst in the degradation of the dye, crystal violet. Also the antibacterial activity of the synthesized CeO2 NPs was evaluated using Staphylococcus aureus (Gram positive bacteria) and Escherichia coli (Gram negative bacteria). CeO2 NPs showed better activity on E. coli than S. aureus. We have demonstrated an eco-friendly preparation of CeO2 nanoparticles, a good photocatalyst and having better antibacterial properties. PMID:27236047

  9. Role of vacancies, light elements and rare-earth metals doping in CeO2

    Science.gov (United States)

    Shi, H.; Hussain, T.; Ahuja, R.; Kang, T. W.; Luo, W.

    2016-01-01

    The magnetic properties and electronic structures of pure, doped and defective cerium oxide (CeO2) have been studied theoretically by means of ab initio calculations based on the density function theory (DFT) with the hybrid HF/DFT technique named PBE0. Carbon (C), nitrogen (N), phosphorus (P), sulphur (S), lanthanum (La) and praseodymium (Pr) doped in CeO2 and CeO2 containing oxygen vacancies (Ov) were considered. Our spin-polarized calculations show that C, N, Pr dopants and Ov defects magnetize the non-magnetic CeO2 in different degree. The optical band gap related to photocatalysis for pure CeO2, corresponding to the ultraviolet region, is reduced obviously by C, N, S, Pr impurities and oxygen vacancies, shifting to the visible region and even further to the infrared range. Especially, N-, S- and Pr-doped CeO2 could be used to photocatalytic water splitting for hydrogen production. As the concentration of Ov increasing up to 5%, the CeO2 exhibits a half-metallic properties. PMID:27554285

  10. Process optimization for the sputter deposition of molybdenum thin films as electrode for AlN thin films

    International Nuclear Information System (INIS)

    Molybdenum thin films have been deposited on Ti/(100) Si substrates by dc sputtering. For process optimization, a design of experiments method was used with three input factors (target power, substrate temperature, and process gas flow). Deposition rate, resistivity, roughness, diffraction angle, and rocking curve width were analyzed as output responses using statistical analysis method. Subsequently, a process allowing the deposition of highly crystalline, smooth, and low resistivity Mo film was selected and tested against film thickness. The as-optimized sputtered molybdenum thin film was used as seeding electrode for the growth of highly c-axis textured AlN film by dc pulsed reactive sputtering

  11. thin films grown with additional NaF layers

    Science.gov (United States)

    Kim, Gee Yeong; Kim, Juran; Jo, William; Son, Dae-Ho; Kim, Dae-Hwan; Kang, Jin-Kyu

    2014-10-01

    CZTS precursors [SLG/Mo (300 nm)/ZnS (460 nm)/SnS (480 nm)/Cu (240 nm)] were deposited by RF/DC sputtering, and then NaF layers (0, 15, and 30 nm) were grown by electron beam evaporation. The precursors were annealed in a furnace with Se metals at 590°C for 20 minutes. The final composition of the CZTSSe thin-films was of Cu/(Zn + Sn) ~ 0.88 and Zn/Sn ~ 1.05, with a metal S/Se ratio estimated at ~0.05. The CZTSSe thin-films have different NaF layer thicknesses in the range from 0 to 30 nm, achieving a ~3% conversion efficiency, and the CZTSSe thin-films contain ~3% of Na. Kelvin probe force microscopy was used to identify the local potential difference that varied according to the thickness of the NaF layer on the CZTSSe thin-films. The potential values at the grain boundaries were observed to increase as the NaF thickness increased. Moreover, the ratio of the positively charged GBs in the CZTSSe thin-films with an NaF layer was higher than that of pure CZTSSe thin-films. A positively charged potential was observed around the grain boundaries of the CZTSSe thin-films, which is a beneficial characteristic that can improve the performance of a device.

  12. Thin film thickness measurements using Scanning White Light Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Maniscalco, B.; Kaminski, P.M.; Walls, J.M., E-mail: J.M.Walls@lboro.ac.uk

    2014-01-01

    Scanning White Light Interferometry is a well-established technique for providing accurate surface roughness measurements and three dimensional topographical images. Here we report on the use of a variant of Scanning White Light Interferometry called coherence correlation interferometry which is now capable of providing accurate thickness measurements from transparent and semi-transparent thin films with thickness below 1 μm. This capability will have many important applications which include measurements on optical coatings, displays, semiconductor devices, transparent conducting oxides and thin film photovoltaics. In this paper we report measurements of thin film thickness made using coherence correlation interferometry on a variety of materials including metal-oxides (Nb{sub 2}O{sub 5} and ZrO{sub 2}), a metal-nitride (SiN{sub x}:H), a carbon-nitride (SiC{sub x}N{sub y}:H) and indium tin oxide, a transparent conducting oxide. The measurements are compared with those obtained using spectroscopic ellipsometry and in all cases excellent correlation is obtained between the techniques. A key advantage of this capability is the combination of thin film thickness and surface roughness and other three-dimensional metrology measurements from the same sample area. - Highlights: • Capability to make thin film measurements with sub-nanometre accuracy • Measurements of thin film thickness made on metal-oxides, nitrides and carbon-nitrides • Excellent correlation with thickness measurements using spectroscopic ellipsometry • Thin film measurement and nanometrology from the same sample area.

  13. Thin film nitinol covered stents: design and animal testing.

    Science.gov (United States)

    Levi, Daniel S; Williams, Ryan J; Liu, Jasen; Danon, Saar; Stepan, Lenka L; Panduranga, Mohanchandra K; Fishbein, Michael C; Carman, Greg P

    2008-01-01

    Interventionalists in many specialties have the need for improved, low profile covered stents. Thin films of nitinol (<5-10 microns) could be used to improve current covered stent technology. A "hot target" sputter deposition technique was used to create thin films of nitinol for this study. Covered stents were created from commercially available balloon-inflatable and self-expanding stents. Stents were deployed in a laboratory flow loop and in four swine. Uncovered stent portions served as controls. Postmortem examinations were performed 2-6 weeks after implantation. In short-term testing, thin film nitinol covered stents deployed in the arterial circulation showed no intimal proliferation and were easily removed from the arterial wall postmortem. Scanning electron microscopy showed a thin layer of endothelial cells on the thin film, which covered the entire film by 3 weeks. By contrast, significant neointimal hyperplasia occurred on the luminal side of stents deployed in the venous circulation. Extremely low-profile covered stents can be manufactured using thin films of nitinol. Although long-term studies are needed, thin film nitinol may allow for the development of low-profile, nonthrombogenic covered stents. PMID:18496269

  14. Thin film thickness measurements using Scanning White Light Interferometry

    International Nuclear Information System (INIS)

    Scanning White Light Interferometry is a well-established technique for providing accurate surface roughness measurements and three dimensional topographical images. Here we report on the use of a variant of Scanning White Light Interferometry called coherence correlation interferometry which is now capable of providing accurate thickness measurements from transparent and semi-transparent thin films with thickness below 1 μm. This capability will have many important applications which include measurements on optical coatings, displays, semiconductor devices, transparent conducting oxides and thin film photovoltaics. In this paper we report measurements of thin film thickness made using coherence correlation interferometry on a variety of materials including metal-oxides (Nb2O5 and ZrO2), a metal-nitride (SiNx:H), a carbon-nitride (SiCxNy:H) and indium tin oxide, a transparent conducting oxide. The measurements are compared with those obtained using spectroscopic ellipsometry and in all cases excellent correlation is obtained between the techniques. A key advantage of this capability is the combination of thin film thickness and surface roughness and other three-dimensional metrology measurements from the same sample area. - Highlights: • Capability to make thin film measurements with sub-nanometre accuracy • Measurements of thin film thickness made on metal-oxides, nitrides and carbon-nitrides • Excellent correlation with thickness measurements using spectroscopic ellipsometry • Thin film measurement and nanometrology from the same sample area

  15. Electron field emission from amorphous semiconductor thin films

    International Nuclear Information System (INIS)

    The flat panel display market requires new and improved technologies in order to keep up with the requirements of modem lifestyles. Electron field emission from thin film amorphous semiconductors is potentially such a technology. For this technology to become viable, improvements in the field emitting properties of these materials must be achieved. To this end, it is important that a better understanding of the emission mechanisms responsible is attained. Amorphous carbon thin films, amorphous silicon thin films and other materials have been deposited, in-house and externally. These materials have been characterised using ellipsometry, profilometry, optical absorption, scanning electron microscopy, atomic force microscopy, electron paramagnetic resonance and Rutherford backscattering spectroscopy. An experimental system for evaluating the electron field emitting performance of thin films has been developed. In the process of developing thin film cathodes in this study, it has been possible to add a new and potentially more useful semiconductor, namely amorphous silicon, to the family of cold cathode emitters. Extensive experimental field emission data from amorphous carbon thin films, amorphous silicon thin films and other materials has been gathered. This data has been used to determine the mechanisms responsible for the observed electron emission. Preliminary computer simulations using appropriate values for the different material properties have exhibited emission mechanisms similar to those identified by experiment. (author)

  16. Novel catalysts: Indium implanted SiO2 thin films

    International Nuclear Information System (INIS)

    Interactions of Indium (In) and silicon (Si) atoms are known to catalyze certain organic chemical reactions with high efficiency. In an attempt of creating a material that manifests the interactions, In implanted SiO2 thin films were prepared by ion beam injection and their catalytic abilities for organic chemical reactions were examined. It has been found that, with an injection energy of approximately 0.5 keV, a thin In film is formed on a SiO2 substrate surface and the In implanted SiO2 thin film can catalyze an organic chemical reaction. It has been also shown that there is an optimal ion dose for the highest catalytic ability in the film preparation process. Thin-film-type catalyzing materials such as the one proposed here may open a new way to enhance surface chemical reaction rates.

  17. Resistivity of thiol-modified gold thin films

    International Nuclear Information System (INIS)

    In this work, we study the effect of thiol self assembled monolayers on the electrical resistivity of metallic thin films. The analysis is based on the Fuchs–Sondheimer–Lucas theory and on electrical transport measurements. We determined resistivity change due to dodecanethiol adsorption on gold thin films. For this purpose, we controlled the deposition and annealing temperatures of the films to change the surface topography and to diminish the effect of electron grain boundary scattering. Results show that the electrical response to the absorption of thiols strongly depends on the initial topography of the surface. - Highlights: • We study the effect of self assembled monolayers on the resistivity of thin films. • Fuchs–Sondheimer theory reproduces the resistivity increase due to thiol deposition. • We determined resistivity change due to dodecanethiol deposition on gold thin films. • The electrical response strongly depends on the substrate surface topography

  18. Electrochemical behavior of chemically synthesized selenium thin film.

    Science.gov (United States)

    Patil, A M; Kumbhar, V S; Chodankar, N R; Lokhande, A C; Lokhande, C D

    2016-05-01

    The facile and low cost simple chemical bath deposition (CBD) method is employed to synthesize red colored selenium thin films. These selenium films are characterized for structural, morphological, topographical and wettability studies. The X-ray diffraction (XRD) pattern showed the crystalline nature of selenium thin film with hexagonal crystal structure. The scanning electron microscopy (SEM) study displays selenium nanoparticles ranging from 20 to 475nm. A specific surface area of 30.5m(2)g(-1) is observed for selenium nanoparticles. The selenium nanoparticles hold mesopores in the range of 1.39nm, taking benefits of the good physicochemical stability and excellent porosity. Subsequently, the electrochemical properties of selenium thin films are deliberated by cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) techniques. The selenium thin film shows specific capacitance (Cs) of 21.98Fg(-1) with 91% electrochemical stability. PMID:26896773

  19. Optical and Structural Properties of Ultra-thin Gold Films

    CERN Document Server

    Kossoy, Anna; Simakov, Denis; Leosson, Kristjan; Kéna-Cohen, Stéphane; Maier, Stefan A

    2014-01-01

    Realizing laterally continuous ultra-thin gold films on transparent substrates is a challenge of significant technological importance. In the present work, formation of ultra-thin gold films on fused silica is studied, demonstrating how suppression of island formation and reduction of plasmonic absorption can be achieved by treating substrates with (3-mercaptopropyl) trimethoxysilane prior to deposition. Void-free fi lms with deposition thickness as low as 5.4 nm are realized and remain structurally stable at room temperature. Based on detailed structural analysis of the fi lms by specular and diffuse X-ray reflectivity measurements, it is shown that optical transmission properties of continuous ultra-thin films can be accounted for using the bulk dielectric function of gold. However, it is important to take into account the non-abrupt transition zone between the metal and the surrounding dielectrics, which extends through several lattice constants for the laterally continuous ultra-thin films (film thickness...

  20. Dynamic mechanical properties of photo resist thin films

    International Nuclear Information System (INIS)

    Photo resist thin films have mainly been used and investigated for versatile applications of micro electronic mechanical systems because of its outstanding aspect ratio and attainable film thickness. An accurate structure properties derived from validated material characterization is required in engineering applications. In this work, dynamic responses of photo resist thin films are tested by a nanoindentation in association with a dynamic mechanical analysis, where the thin film is coated on a silicon wafer by spin coating. The results show that the storage modulus of the photo resist thin film remains constant at the beginning and then increases as the indentation depth increases. Meanwhile, the loss modulus increases as the indentation depth increases. Varying the film thickness shows that the substrate effect plays an important role in determining the dynamic properties of thin films. However, the results agree well with the bulk material when the amplitude of nanoindentation is relatively small. It illustrates the dynamic mechanical analysis can be an efficient method to characterize the viscoelastic properties of thin films, but proper attention on the test parameters is needed

  1. Nanomechanical behavior of (1 0 0) oriented titanium thin films

    Science.gov (United States)

    Vasu, Kuraganti; Ghanashyam Krishna, Mamidipudi; Padmanabhan, Kuppuswamy Anantha

    2014-03-01

    Titanium thin films were deposited on single crystal Si (3 1 1) and polycrystalline 316 LN nuclear grade stainless steel substrates by RF magnetron sputtering. X-ray diffraction revealed that, irrespective of substrate type, films exhibit preferential growth along the (1 0 0) plane. The microstructure of the films corresponds to the zone-I type in structure zone model on both substrates. The hardness and Young's modulus of the films were extracted from load-displacement curves. The maximum values of hardness and Young's modulus were 12 and 132 GPa respectively for 220 nm thin film on SS substrate. The electrical resistivity data revealed that the films are metallic in nature and the resistivity is lower in the case of the 220 nm thickness film, on both substrates. The observed changes in mechanical and electrical properties can be correlated with variations in the microstructure of Ti films.

  2. Oxygen storage and catalytic NO removal promoted by CeO2-containing mixed oxides

    International Nuclear Information System (INIS)

    CeO2-ZrO2 mixed oxides show improved redox properties as compared to CeO2 which makes them important innovative materials for three-way catalysts. The origin of this effect and the structural/redox correlation are discussed. The influence of the improved redox capacities on the reduction of NO by CO catalyzed by Rh/CeO2-ZrO2 catalysts is reported and evidence for an active role of the CeO2-ZrO2 support in NO activation is presented. (orig.)

  3. Molecular simulation of freestanding amorphous nickel thin films

    Energy Technology Data Exchange (ETDEWEB)

    Dong, T.Q. [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, UMR 8208 CNRS, 5 Boulevard Descartes, 77454 Marne-la-Vallée, Cedex 2 (France); Hoang, V.V., E-mail: vvhoang2002@yahoo.com [Department of Physics, Institute of Technology, National University of Ho Chi Minh City, 268 Ly Thuong Kiet Street, District 10, Ho Chi Minh City (Viet Nam); Lauriat, G. [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, UMR 8208 CNRS, 5 Boulevard Descartes, 77454 Marne-la-Vallée, Cedex 2 (France)

    2013-10-31

    Size effects on glass formation in freestanding Ni thin films have been studied via molecular dynamics simulation with the n-body Gupta interatomic potential. Atomic mechanism of glass formation in the films is determined via analysis of the spatio-temporal arrangements of solid-like atoms occurred upon cooling from the melt. Solid-like atoms are detected via the Lindemann ratio. We find that solid-like atoms initiate and grow mainly in the interior of the film and grow outward. Their number increases with decreasing temperature and at a glass transition temperature they dominate in the system to form a relatively rigid glassy state of a thin film shape. We find the existence of a mobile surface layer in both liquid and glassy states which can play an important role in various surface properties of amorphous Ni thin films. We find that glass formation is size independent for models containing 4000 to 108,000 atoms. Moreover, structure of amorphous Ni thin films has been studied in details via coordination number, Honeycutt–Andersen analysis, and density profile which reveal that amorphous thin films exhibit two different parts: interior and surface layer. The former exhibits almost the same structure like that found for the bulk while the latter behaves a more porous structure containing a large amount of undercoordinated sites which are the origin of various surface behaviors of the amorphous Ni or Ni-based thin films found in practice. - Highlights: • Glass formation is analyzed via spatio-temporal arrangements of solid-like atoms. • Amorphous Ni thin film exhibits two different parts: surface and interior. • Mobile surface layer enhances various surface properties of the amorphous Ni thin films. • Undercoordinated sites play an important role in various surface activities.

  4. Germanium Lift-Off Masks for Thin Metal Film Patterning

    Science.gov (United States)

    Brown, Ari

    2012-01-01

    A technique has been developed for patterning thin metallic films that are, in turn, used to fabricate microelectronics circuitry and thin-film sensors. The technique uses germanium thin films as lift-off masks. This requires development of a technique to strip or undercut the germanium chemically without affecting the deposited metal. Unlike in the case of conventional polymeric lift-off masks, the substrate can be exposed to very high temperatures during processing (sputter deposition). The reason why polymeric liftoff masks cannot be exposed to very high temperatures (greater than 100 C) is because (a) they can become cross linked, making lift-off very difficult if not impossible, and (b) they can outgas nitrogen and oxygen, which then can react with the metal being deposited. Consequently, this innovation is expected to find use in the fabrication of transition edge sensors and microwave kinetic inductance detectors, which use thin superconducting films deposited at high temperature as their sensing elements. Transition edge sensors, microwave kinetic inductance detectors, and their circuitry are comprised of superconducting thin films, for example Nb and TiN. Reactive ion etching can be used to pattern these films; however, reactive ion etching also damages the underlying substrate, which is unwanted in many instances. Polymeric lift-off techniques permit thin-film patterning without any substrate damage, but they are difficult to remove and the polymer can outgas during thin-film deposition. The outgassed material can then react with the film with the consequence of altered and non-reproducible materials properties, which, in turn, is deleterious for sensors and their circuitry. The purpose of this innovation was to fabricate a germanium lift-off mask to be used for patterning thin metal films.

  5. Development of neutron diffuse scattering analysis code by thin film and multilayer film

    International Nuclear Information System (INIS)

    To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering by thin film, roughness of surface of thin film, correlation function, neutron propagation by thin film, diffuse scattering by DWBA theory, measurement model, SDIFFF (neutron diffuse scattering analysis program by thin film) and simulation results are explained. On neutron diffuse scattering by multilayer film, roughness of multilayer film, principle of diffuse scattering, measurement method and simulation examples by MDIFF (neutron diffuse scattering analysis program by multilayer film) are explained. (S.Y.)To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering

  6. Thin liquid film flow and heat transfer under spray impingement

    International Nuclear Information System (INIS)

    A mathematical model was derived to investigate thin liquid film flow under spray impingement. Based on predicted flow patterns, a heat transfer model was developed to investigate the heat transfer performance in the non-boiling regime of spray cooling. The film thickness predicted by the thin film flow model favourably compares with reported experimental results obtained at different measurement locations and nozzle inlet pressures. It is found that the film thickness is sensitive to droplet flux distribution but not the nozzle inlet pressure. The comparison of the heated surface temperature between the proposed heat transfer model and the published experimental data shows good agreement. - Highlights: ► Thin liquid film flow in spray cooling is theoretically studied. ► A thin liquid film flow model is derived to predict the thin film flow pattern under spray impingement. ► A heat transfer model is developed to predict the heat transfer performance in the non-boiling regime of spray cooling. ► Film thickness of the liquid film flow is sensitive to droplet flux distribution but not the nozzle inlet pressure. ► Droplet impingement cooling is the primary cooling mechanism in the non-boiling regime of spray cooling.

  7. Buckling of Thin Films in Nano-Scale

    Directory of Open Access Journals (Sweden)

    Li L.A.

    2010-06-01

    Full Text Available Investigation of thin film buckling is important for life prediction of MEMS device which are damaged mainly by the delamination and buckling of thin films. In this paper the mechanical and thermal properties of compressed thin film titanium films with 150 nm thickness deposited on an organic glass substrate under mechanical and thermal loads were measured and characterized. In order to simulate the thin films which subjected to compound loads and the buckle modes the external uniaxial compression and thermal loading were subjected to the specimen by the symmetric loading device and the electrical film in this experiment. The temperature of the thin film deposited on substrate was measured using thermoelectric couple. The range of temperature accords with the temperature range of the MEMS. It is found that the size and number of the delamination and buckling of the film are depended upon the pre-fixed mechanical loading and thermal temperature. The thermal transient conduction and thermal stability of the film and substrate was studied with finite element method.

  8. Fracture of nanoporous organosilicate thin films

    Science.gov (United States)

    Gage, David Maxwell

    Nanoporous organosilicate thin films are attractive candidates for a number of emerging technologies, ranging from biotechnology to optics and microelectronics. However, integration of these materials is challenged by their fragile nature and susceptibility to mechanical failure. Debonding and cohesive cracking of the organosilicate film are principal concerns that threaten the reliability and yield of device structures. Despite the intense interest in these materials, there is currently a need for greater understanding of the relationship between glass structure and thermomechanical integrity. The objective of this research was to investigate strategies for improving mechanical performance through variations in film chemistry, process conditions, and pore morphology. Several approaches to effecting improvements in elastic and fracture properties were examined in depth, including post-deposition curing, molecular reinforcement using hydrocarbon network groups, and manipulation of pore size and architecture. Detailed structural characterization was employed along with quantitative fracture mechanics based testing methods. It was shown that ultra-violet irradiation and electron bombardment post-deposition treatments can significantly impact glass structure in ways that cannot be achieved through thermal activation alone. Both techniques demonstrated high porogen removal efficiency and enhanced the glass matrix through increased network connectivity and local bond rearrangements. The increases in network connectivity were achieved predominantly through the replacement of terminal groups, particularly methyl and silanol groups, with Si-O network bonds. Nuclear magnetic resonance spectroscopy was shown to be a powerful and quantitative method for gaining new insight into the underlying cure reactions and mechanisms. It was demonstrated that curing leads to significant progressive enhancement of elastic modulus and adhesive fracture energies due to increased network bond

  9. Electrochromic properties of nanocrystalline MoO3 thin films

    International Nuclear Information System (INIS)

    Electrochromic MoO3 thin films were prepared by a sol-gel spin-coating technique. The spin-coated films were initially amorphous; they were calcined, producing nanocrystalline MoO3 thin films. The effects of annealing temperatures ranging from 100 oC to 500 oC were investigated. The electrochemical and electrochromic properties of the films were measured by cyclic voltammetry and by in-situ optical transmittance techniques in 1 M LiClO4/propylene carbonate electrolyte. Experimental results showed that the transmittance of MoO3 thin films heat-treated at 350 oC varied from 80% to 35% at λ = 550 nm (ΔT = ∼ 45%) and from 86% to 21% at λ ≥ 700 nm (ΔT = ∼ 65%) after coloration. Films heat-treated at 350 deg. C exhibited the best electrochromic properties in the present study

  10. Microstructural characterization of Sr Ti O3 thin films

    International Nuclear Information System (INIS)

    Sr Ti O3 thin films (obtained by polymeric precursors) were dip coated on Mg O (100) monocrystal substrates. After different thermal treatment at 850 deg C, these films were characterized by SEM and, through selective chemical attack, the films were detached from the substrates and characterized by TEM. The results showed that the thermal treatment and the atmosphere influence strongly the crystallization, densification and the grain size of these films. (author)

  11. Chemical Liquid Phase Deposition of Thin Aluminum Oxide Films

    OpenAIRE

    Sun, Jie; Sun, Yingchun

    2007-01-01

    Thin aluminum oxide films were deposited by a new and simple physicochemical method called chemical liquid phase deposition (CLD) on semiconductor materials. Aluminum sulfate with crystallized water and sodium bicarbonate were used as precursors for film growth, and the control of the system pH value played an important role in this experiment. The growth rate is 12 nm/h at room temperature. Post-growth annealing not only densifies and purifies the films, but results in film crystallization a...

  12. Nonlinear absorption of ultrashort laser pulses in thin metal films

    OpenAIRE

    Manfredi, Giovanni; Hervieux, Paul-Antoine

    2005-01-01

    Self-consistent simulations of the ultrafast electron dynamics in thin metal films are performed. A regime of nonlinear oscillations is observed, which corresponds to ballistic electrons bouncing back and forth against the film surfaces. When an oscillatory laser field is applied to the film, the field energy is partially absorbed by the electron gas. Maximum absorption occurs when the period of the external field matches the period of the nonlinear oscillations, which, for sodium films, lies...

  13. Electro-optical Properties of Ultra-Thin Organic Films

    OpenAIRE

    Hodges, Ping Y.

    2001-01-01

    Electro-optical properties of thin film are of great interest owing to the perpetual demand for miniaturization and higher speed devices for communication, electronic, and biomedical applications. The thickness of polymer films developed for these applications has decreased dramatically making interfacial effects significant. It is well documented that, in submicron thickness range, both film/substrate & film/air interface are critical. In this study, we probe the dynamics of electro-optic...

  14. Preparation and superconductivity of iron selenide thin films

    OpenAIRE

    Han, Y.; Li, W. Y.; Cao, L. X.; S. Zhang; Xu, B; Zhao, B. R.

    2009-01-01

    FeSex (x = 0.80, 0.84, 0.88, 0.92) thin films were prepared on SrTiO3(001) (STO), (La,Sr)(Al,Ta)O3(001) (LSAT), and LaAlO3(001) (LAO) substrates by pulsed laser deposition method. All thin films show single-phase and c-axis oriented epitaxial growth, and are superconducting. Among them, the FeSe0.88 thin films show Tc, onset of 11.8 K and Tc, 0 of 3.4 K. The upper critical magnetic field is estimated to be 14.0 T.

  15. Double Laser for Depth Measurement of Thin Films of Ice.

    Science.gov (United States)

    Beltrán, Manuel Domingo; Molina, Ramón Luna; Aznar, Miguel Ángel Satorre; Moltó, Carmina Santonja; Verdú, Carlos Millán

    2015-01-01

    The use of thin films is extensive in both science and industry. We have created an experimental system that allows us to measure the thicknesses of thin films (with typical thicknesses of around 1 µm) in real time without the need for any prior knowledge or parameters. Using the proposed system, we can also measure the refractive index of the thin film material exactly under the same experimental conditions. We have also obtained interesting results with regard to structural changes in the solid substance with changing temperature and have observed the corresponding behavior of mixtures of substances. PMID:26426024

  16. Organic nanostructured thin film devices and coatings for clean energy

    CERN Document Server

    Zhang, Sam

    2010-01-01

    Authored by leading experts from around the world, the three-volume Handbook of Nanostructured Thin Films and Coatings gives scientific researchers and product engineers a resource as dynamic and flexible as the field itself. The first two volumes cover the latest research and application of the mechanical and functional properties of thin films and coatings, while the third volume explores the cutting-edge organic nanostructured devices used to produce clean energy. This third volume, Organic Nanostructured Thin Film Devices and Coatings for Clean Energy, addresses various aspects of the proc

  17. Light management in thin-film silicon solar cells

    OpenAIRE

    Isabella, O.

    2013-01-01

    Solar energy can fulfil mankind’s energy needs and secure a more balanced distribution of primary sources of energy. Wafer-based and thin-film silicon solar cells dominate todays’ photovoltaic market because silicon is a non-toxic and abundant material and high conversion efficiencies are achieved with silicon-based solar cells. To stay competitive with bulk crystalline silicon and other thin-film solar cell technologies, thin-film silicon solar cells have to achieve a conversion efficiency l...

  18. Optical modeling and simulation of thin-film photovoltaic devices

    CERN Document Server

    Krc, Janez

    2013-01-01

    In wafer-based and thin-film photovoltaic (PV) devices, the management of light is a crucial aspect of optimization since trapping sunlight in active parts of PV devices is essential for efficient energy conversions. Optical modeling and simulation enable efficient analysis and optimization of the optical situation in optoelectronic and PV devices. Optical Modeling and Simulation of Thin-Film Photovoltaic Devices provides readers with a thorough guide to performing optical modeling and simulations of thin-film solar cells and PV modules. It offers insight on examples of existing optical models

  19. Hydrogenation Effect on Mg/Co Multilayer Thin Films

    OpenAIRE

    M.K. Jangid; S.P. NEHRA, M.SINGH

    2010-01-01

    Multilayer Mg/Co thin films have been prepared using thermal evaporation method at pressure 10-5torr. Annealing of structure has been performed in atmospheric condition at 600 K constant temperature for one hour. Hydrogenation of annealed thin films has been performed by keeping these in hydrogenation cell at different hydrogen pressures for 30 min. The UV–VIS absorption spectra of thin films have been carried out at room temperature in the wavelength range of 300–800 nm. The optical band gap...

  20. Copper zinc tin sulfide-based thin film solar cells

    CERN Document Server

    Ito, Kentaro

    2014-01-01

    Beginning with an overview and historical background of Copper Zinc Tin Sulphide (CZTS) technology, subsequent chapters cover properties of CZTS thin films, different preparation methods of CZTS thin films, a comparative study of CZTS and CIGS solar cell, computational approach, and future applications of CZTS thin film solar modules to both ground-mount and rooftop installation. The semiconducting compound (CZTS) is made up earth-abundant, low-cost and non-toxic elements, which make it an ideal candidate to replace Cu(In,Ga)Se2 (CIGS) and CdTe solar cells which face material scarcity and tox

  1. The state of the art of thin-film photovoltaics

    International Nuclear Information System (INIS)

    Thin-film photovoltaic technologies, based on materials such as amorphous or polycrystalline silicon, copper indium diselenide, cadmium telluride, and gallium arsenide, offer the potential for significantly reducing the cost of electricity generated by photovoltaics. The significant progress in the technologies, from the laboratory to the marketplace, is reviewed. The common concerns and questions raised about thin films are addressed. Based on the progress to date and the potential of these technologies, along with continuing investments by the private sector to commercialize the technologies, one can conclude that thin-film PV will provide a competitive alternative for large-scale power generation in the future

  2. Assembly and Applications of Carbon Nanotube Thin Films

    Institute of Scientific and Technical Information of China (English)

    Hongwei ZHU; Bingqing WEI

    2008-01-01

    The ultimate goal of current research on carbon nanotubes (CNTs) is to make breakthroughs that advance nanotechnological applications of bulk CNT materials. Especially, there has been growing interest in CNT thin films because of their unique and usually enhanced properties and tremendous potential as components for use in nano-electronic and nano-mechanical device applications or as structural elements in various devices. If a synthetic or a post processing method can produce high yield of nanotube thin films, these structures will provide tremendous potential for fundamental research on these devices. This review will address the synthesis, the post processing and the device applications of self-assembled nanotube thin films.

  3. Local deposition and patterning of catalytic thin films in microsystems

    International Nuclear Information System (INIS)

    The local deposition of catalysts is desired in a wide range of catalytic microsystems (microreactors and sensors). In this study, we investigate technologies enabling deposition and patterning of catalyst thin films in a manner compatible with standard micromachining processes. We evaluate and compare deposition techniques based on a combination of a self-assembly, soft-lithography and conventional micromachining. Platinum (Pt) and palladium (Pd) were used as model catalysts, both as a sputtered thin film and as nanoparticles supported on γ-alumina. The thin films were characterized and tested in terms of their catalytic activity based on CO chemisorption measurements, stability and reproducibility. (paper)

  4. Mechanical properties of metallic thin films: theoretical approach

    Science.gov (United States)

    Phuong, Duong Dai; Hoa, Nguyen Thi; Van Hung, Vu; Khoa, Doan Quoc; Hieu, Ho Khac

    2016-03-01

    The statistical moment method in statistical mechanics was developed to investigate the mechanical properties of free-standing metallic thin films at ambient conditions including the anharmonicity effects of thermal lattice vibrations. Analytical expressions of isothermal areal modulus B T , Young's modulus E and shear modulus G were derived in terms of the power moments of the atomic displacements. Numerical calculations have been performed for metallic Ni, Au and Al thin films, and compared with those of bulk metals. This method is physically transparent and it successfully described the temperature effects on mechanical properties of metallic thin films.

  5. Thin-film organic photonics molecular layer deposition and applications

    CERN Document Server

    Yoshimura, Tetsuzo

    2011-01-01

    Among the many atomic/molecular assembling techniques used to develop artificial materials, molecular layer deposition (MLD) continues to receive special attention as the next-generation growth technique for organic thin-film materials used in photonics and electronics. Thin-Film Organic Photonics: Molecular Layer Deposition and Applications describes how photonic/electronic properties of thin films can be improved through MLD, which enables precise control of atomic and molecular arrangements to construct a wire network that achieves ""three-dimensional growth"". MLD facilitates dot-by-dot--o

  6. Room temperature redox reaction by oxide ion migration at carbon/Gd-doped CeO2 heterointerface probed by an in situ hard x-ray photoemission and soft x-ray absorption spectroscopies

    Directory of Open Access Journals (Sweden)

    Takashi Tsuchiya, Shogo Miyoshi, Yoshiyuki Yamashita, Hideki Yoshikawa, Kazuya Terabe, Keisuke Kobayashi and Shu Yamaguchi

    2013-01-01

    Full Text Available In situ hard x-ray photoemission spectroscopy (HX-PES and soft x-ray absorption spectroscopy (SX-XAS have been employed to investigate a local redox reaction at the carbon/Gd-doped CeO2 (GDC thin film heterointerface under applied dc bias. In HX-PES, Ce3d and O1s core levels show a parallel chemical shift as large as 3.2 eV, corresponding to the redox window where ionic conductivity is predominant. The window width is equal to the energy gap between donor and acceptor levels of the GDC electrolyte. The Ce M-edge SX-XAS spectra also show a considerable increase of Ce3+ satellite peak intensity, corresponding to electrochemical reduction by oxide ion migration. In addition to the reversible redox reaction, two distinct phenomena by the electrochemical transport of oxide ions are observed as an irreversible reduction of the entire oxide film by O2 evolution from the GDC film to the gas phase, as well as a vigorous precipitation of oxygen gas at the bottom electrode to lift off the GDC film. These in situ spectroscopic observations describe well the electrochemical polarization behavior of a metal/GDC/metal capacitor-like two-electrode cell at room temperature.

  7. Fluorescent thin gel films using organic dyes and pigments

    Science.gov (United States)

    Nakazumi, Hiroyuki; Takashi, Tarao; Taniguchi, Shin-ichi; Nanto, Hidehito

    1997-10-01

    New organic-inorganic fluorescent thin gel films included with laser dyes or fluorescent organic pigments have been prepared for display application. The florescent dyes (benzoxazolium, pyrromethene, and rhodamine dyes) and super-fine particles of fluorescent pigments (coumarin and perylene) were successfully incorporated into thin silicate gel films prepared from tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), and methoxysilane oligomer (MTSO) under acid catalyzed hydrolysis. The blue, green, and red luminescence were observed from these thin films (thickness: 100 - 400 nm), respectively. Fluorescence spectra, fluorescent quantum yield and lifetime of thin gel films are examined. Fluorescent peaks for most of dyes and pigments used in gel films were similar to those in solution, and fluorescent lifetime for dyes and pigments used in gel films were 2.9 - 4.5 ns. Photostability of fluorescent gel films is dependent on fluorescent organic dyes and pigments used and/or silicate gel matrixes. Coumarin and perylene pigments have higher fluorescent quantum yield in gel film prepared from MTSO. The large Stokes shift was observed in fluorescent gel film using coumarin and benzoxazolium dyes. The coumarin and perylene pigments are significantly photo- stable in gel film prepared from MTSO, and photodegradation of perylene red after irradiation of 500 W Xi-lamp for 30 min is below 20%.

  8. Fabrication and Analysis of Thin Film Supercapacitor using a Cobalt Oxide Thin Film Electrode

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H. K.; Lim, J. H.; Jeon, E. J.; Cho, W. I.; Yoon, Y. S. [Korea Institute of Science and Technology, Seoul (Korea); Seong, T. Y. [Kwangju Institute of Science and Technology, Kwangju (Korea)

    2001-05-01

    An all solid-state thin film supercapacitor (TFSC) with Co{sub 3}O{sub 4}/LiPON/Co{sub 3}O{sub 4} structure was fabricated on Pt/Ti/Si substrate using Co{sub 3}O{sub 4} thin film electrode. Each Co{sub 3}O{sub 4} film was grown by reactive dc reactive magnetron sputtering with increasing O{sub 2}/[Ar+O{sub 2}] ratio. Amorphous LiPON electrolyte film was deposited on Co{sub 3}O{sub 4}/Pt/Ti/Si in pure nitrogen ambient by using reactive rf magnetron sputtering. The electrochemical behavior of the Co{sub 3}O{sub 4}/LiPON/Co{sub 3}O{sub 4} multi-layer structures exhibits a behavior of a bulk-type supercapacitor, even though much lower capacity (from 5 to 25 mF/cm{sup 2}-{mu}m) than that of the bulk one. It was found that the TFSC showed a fairly constant discharge capacity with a constant current of 50{mu} A/cm{sup 2} at the cut-off voltage 0-2V during 400 cycles. It is shown that the electrochemical behavior of the Co{sub 3}O{sub 4}/LiPON/Co{sub 3}O{sub 4} TFSC is dependent upon the sputtering gas ratio. The capacity dependency of electrode films on different gas ratios was explained by different structural, electrical, and surfacical properties. (author). 15 refs., 8 figs.

  9. Soft Magnetic Multilayered Thin Films for HF Applications

    Science.gov (United States)

    Loizos, George; Giannopoulos, George; Serletis, Christos; Maity, Tuhin; Roy, Saibal; Lupu, Nicoleta; Kijima, Hanae; Yamaguchi, Masahiro; Niarchos, Dimitris

    Multilayered thin films from various soft magnetic materials were successfully prepared by magnetron sputtering in Ar atmosphere. The magnetic properties and microstructure were investigated. It is found that the films show good soft magnetic properties: magnetic coercivity of 1-10 Oe and saturation magnetization higher than 1T. The initial permeability of the films is greater than 300 and flattens up to 600 MHz. The multilayer thin film properties in combination with their easy, fast and reproducible fabrication indicate that they are potential candidates for high frequency applications.

  10. Strain Relaxation and Vacancy Creation in Thin Platinum Films

    International Nuclear Information System (INIS)

    Synchrotron based combined in situ x-ray diffractometry and reflectometry is used to investigate the role of vacancies for the relaxation of residual stress in thin metallic Pt films. From the experimentally determined relative changes of the lattice parameter a and of the film thickness L the modification of vacancy concentration and residual strain was derived as a function of annealing time at 130 deg. C. The results indicate that relaxation of strain resulting from compressive stress is accompanied by the creation of vacancies at the free film surface. This proves experimentally the postulated dominant role of vacancies for stress relaxation in thin metal films close to room temperature.

  11. Low temperature polymeric precursor derived zinc oxide thin films

    Science.gov (United States)

    Choppali, Uma

    Zinc oxide (ZnO) is a versatile environmentally benign II-VI direct wide band gap semiconductor with several technologically plausible applications such as transparent conducting oxide in flat panel and flexible displays. Hence, ZnO thin films have to be processed below the glass transition temperatures of polymeric substrates used in flexible displays. ZnO thin films were synthesized via aqueous polymeric precursor process by different metallic salt routes using ethylene glycol, glycerol, citric acid, and ethylene diamine tetraacetic acid (EDTA) as chelating agents. ZnO thin films, derived from ethylene glycol based polymeric precursor, exhibit flower-like morphology whereas thin films derived of other precursors illustrate crack free nanocrystalline films. ZnO thin films on sapphire substrates show an increase in preferential orientation along the (002) plane with increase in annealing temperature. The polymeric precursors have also been used in fabricating maskless patterned ZnO thin films in a single step using the commercial Maskless Mesoscale Materials Deposition (M3D(TM)) system.

  12. The influence of CeO2 on the corrosion resistance of laser remelted alloy spray coatings on steel

    International Nuclear Information System (INIS)

    The main compositions of iron-base amorphous self-fluxing alloy powders of 150 mesh, used in this work, are Fe, Cr, Ni, W, Mo, B, Si and C. The ranges of each element in at% are (65-70)Fe, (3-5)Cr, (2-4)Ni, (2-4)W, (1-2)Mo, (10-14)B, (4-7)Si and (2-3)C. The atomic ratio of metal-metalloid is about 80:20, so this alloy is abbreviated as M80X20. The material on which coatings were deposited is 1020 steel, austenitized for 1h at 880 C, water quenched, and tempered at 180 C for 1h. This heat treatment resulted in a low carbon martensite structure with a hardness of HRC35-45. After cleaning, shot blasting and preheating the steel to about 200 C, the authors sprayed a thin Ni-Al alloy layer of about 0.1--0.15mm in thickness onto the specimen by means of an oxygen-acetylene torch to provide better bonding of the coating with substrate. Then the M80X20 and M80X20+8%CeO2 alloy coatings were sprayed to a thickness of about 0.6--0.8mm. The CeO2 was added as particles of 200 mesh, injected into the spray, and became a component of the alloy coating. A single pass remelting process for the coating was then conducted by means of a 3kW CO2 laser. Corrosion tests gave the following results: (1) The addition of rare earth (8%CeO2) can improve the corrosion resistance of the laser-remelted M80X20 alloy layer remarkably, resulting in an obvious decrease of the values of ip and i'p, and hence significant improvement of passivation. (2) The addition of rare earth (8%CeO2) lowers the corrosion rate (the corrosion rate is reduced to approximately one-third of that without rare earth) of the laser remelted M80X20 alloy coating and also changes the corrosion morphology

  13. The optical properties of YBCO thin films

    Science.gov (United States)

    Wallace, Roger James

    We present strong evidence that there is no specific mid- infrared absorption band in YBCO and a generalised Drude model can be used to explain all of the observed features in the optical spectrum. A high vacuum, low temperature ATR experiment has been used to excite surface plasmons (SPP) on YBCO thin films at different temperatures. We have found that the SPP resonance condition varies systematically with temperature. The temperature dependent dielectric function and optical conductivity of YBCO at 2984nm have been determined. We have shown that the renal and imaginary dielectric function of YBCO, ~ɛ= ɛ1 + iɛ2, at 2984nm, are linearly dependent on temperature: ɛ1(T) = -52 + 0.008T and ɛ1(T) = 4 + 0.1T. We have calculated the optical conductivity, σ(T), and the normal reflectance, ℜ(T): σ(T) = 196 + 4.9T and ℜ(T) = 0.99-7.4 × 10-4T, where temperature is in kelvin and the conductivity is in Ω-1 cm-1. A generalised Drude model has been used to analyse our results. The generalised Drude memory function, M = 1//tau + i/omega/lambda, has been calculated as a function of temperature. The parameters 1/τ and λ can be approximated by 1/τ(T) = 50 + 6.6T and 1 + λ(T) ≅ 1.48 - 0.003T +.35 × 10-5T. These expressions are valid between 100K and 300K. An optical technique for determining the thickness of YBCO thin films has been developed. It has been used in an investigation of laser ablated plasmas. We have observed that the limit of material in the plasma plume is not the same as the limit of the luminosity of the plume. The angular distribution of material can be modelled by a cos n/Theta function over much of the range but a combined cos n/Theta + cos m/Theta function is required to describe the distribution near the visible tip of the plume.

  14. Chemical analysis of thin films at Sandia National Laboratories

    International Nuclear Information System (INIS)

    The characterization of thin films produced by chemical and physical vapor deposition requires special analytical techniques. When the average compositions of the films are required, dissolution of the thin films and measurement of the concentrations of the solubilized species is the appropriate analytical approach. In this report techniques for the wet chemical analysis of thin films of Si:Al, P2O5:SiO2, B2O3:SiO2, TiB/sub x/ and TaB/sub x/ are described. The analyses are complicated by the small total quantities of these analytes present in the films, the refractory characters of these analytes, and the possibility of interferences from the substrates on which the films are deposited. Etching conditions are described which dissolve the thin films without introducing interferences from the substrates. A chemical amplification technique and inductively coupled plasma atomic emission spectrometry are shown to provide the sensitivity required to measure the small total quantities (micrograms to milligrams) of analytes present. Also the chemical analysis data has been used to calibrate normal infrared absorption spectroscopy to give fast estimates of the phosphorus and/or boron dopant levels in thin SiO2 films

  15. Production of nickel oxide thin films by magnetron sputtering

    International Nuclear Information System (INIS)

    Discrepancies between short-circuit diffusion data derived from nickel oxide bicrystals and specimens produced by the oxidation of nickel has led to a requirement for thin film nickel oxide specimens of controlled microstructure and impurity level that can be produced independently of the oxidation process. RF magnetron sputtering of nickel oxide has been used to produce thin films intended for this application. The as-deposited films contain excess oxygen compared to stoichiometric nickel oxide and exhibit strong preferred orientation. Annealing in argon leads to oxygen deficient films. The reduction in porosity which accompanies the annealing leads to the formation of through-thickness cracks in the films. Subsequent oxygen tracer studies demonstrate that the cracks give rise to excessive oxygen transport through the films compared to that expected for thermally oxidised scales. The microstructural anomalies produced by the annealing process mean that the required microstructures were not achieved and these films are not useful analogues of thermal nickel oxide scales. (author)

  16. Self-template hydrothermal synthesis of CeO2 hollow nanospheres

    International Nuclear Information System (INIS)

    CeO2 hollow nanospheres were synthesized by a low-cost and environmentally benign one-pot hydrothermal route. Templates, surfactants, or other auxiliaries were not used in the route. X-ray diffraction, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and nitrogen adsorption–desorption measurements were used to characterize the products. The average diameter of hollow spheres, with shells of approximately 30 nm, was about 300 nm. The formation of these hollow spheres involved a transformation from Ce(OH)CO3 solid spheres to CeO2 hollow nanospheres. The CeO2 hollow nanospheres exhibited a higher catalytic activity on CO oxidation than CeO2 nano-octahedrons.

  17. Fruit juice extract mediated synthesis of CeO2 nanoparticles for antibacterial and photocatalytic activities

    Science.gov (United States)

    Reddy Yadav, L. S.; Manjunath, K.; Archana, B.; Madhu, C.; Raja Naika, H.; Nagabhushana, H.; Kavitha, C.; Nagaraju, G.

    2016-05-01

    Ceria ( CeO2 is a technologically important rare-earth material because of its unique properties and various engineering/biological applications. In the present work, cerium oxide nanoparticles have been prepared by a simple solution combustion method using watermelon juice as a novel combustible fuel. The structure and morphology of the synthesized CeO2 nanoparticles were analyzed using various analytical tools such as PXRD, FTIR, Raman, UV-Visible and SEM. PXRD pattern confirms that the prepared material is composed of cubic-phase cerium oxide nanoparticles. Photocatalytic degradation of Methylene blue dye using CeO2 nanoparticles shows 98% of degradation in UV irradiations. Furthermore the antibacterial properties of CeO2 nanoparticles were investigated by their bacterial activity against two bacterial strains using the agar well diffusion method.

  18. Deposition, Characterization, And Simulation Of Thin Films With Form Birefringence

    Science.gov (United States)

    Jacobson, M. R.; Horowitz, F.; Liao, Bangjun

    1984-12-01

    Birefringence in optical thin films due to structure on a scale large compared to atoms but small compared to optical wavelengths, known as form birefringence (FB), was observed almost a century ago. More recently, studies of obliquely deposited metal films stimulated new interest in birefringent films. The link between structure, which is predominantly columnar in evaporated thin films, and birefringence has been conclusively demonstrated through ellipsometric measurement and modeling. Direct measurements of form birefringence are especially tedious in tilted films, since essentially four quantities must be derived: three indices of refraction and the film thickness. Clearly, four measurements are required; Horowitz' used an ellipsometric method to perform such measurements on a zirconium oxide (Zr02) film. Later, a 4.6-μm-thick film of Zr02 was obliquely deposited; spectrophotometric measurements revealed its utility as a half-wave plate. A parallel effort directed at understanding FB films through computer simulations has been undertaken by Sikkens and Liao. These simulations can be specialized to include defects, epitaxy, and anisotropic surface mobility. Applications of obliquely deposited FB films of familiar thin film materials can be anticipated if their structure and performance can be more thoroughly understood.

  19. Investigation on guided wave dispersion characteristics for metal thin films

    International Nuclear Information System (INIS)

    In this study, we investigated the dispersion characteristics of guided waves in thin films. Dispersion curves are essential for understanding not only the behavior of ultrasonic waves, but also the mechanical properties of thin films. Matrix techniques are presented for modeling ultrasonic waves in multilayered structures before being used to calculate the dispersion curves for Al-steel and Al-composite specimens. When compared with the dispersion curves obtained using the commercial program (Disperse), the dispersion curves generated from the transfer matrix method show its validity. These developed methods are used to obtain dispersion curves for Al thin films deposited on a Si substrate. The resulting dispersion curves enable observation of both dispersive and non-dispersive behavior for the guided waves, depending on the thickness of the thin films.

  20. Rip-Stop Reinforced Thin Film Sun Shield Structure Project

    Data.gov (United States)

    National Aeronautics and Space Administration — During a proposed Phase I and Phase II program, PSI will advance the TRL from 3 to 6 for the ripstop reinforcement of thin film membranes used for large deployable...