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Sample records for superconductor thick films

  1. Percolation effect in thick film superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sali, R.; Harsanyi, G. [Technical Univ. of Budapest (Hungary)

    1994-12-31

    A thick film superconductor paste has been developed to study the properties of granulated superconductor materials, to observe the percolation effect and to confirm the theory of the conducting mechanism in the superconducting thick films. This paste was also applied to make a superconducting planar transformer. Due to high T{sub c} and advantageous current density properties the base of the paste was chosen to be of Bi(Pb)SrCaCuO system. For contacts a conventional Ag/Pt paste was used. The critical temperature of the samples were between 110 K and 115 K depending on the printed layer thickness. The critical current density at the boiling temperature of the liquid He- was between 200-300 A/cm{sup 2}. The R(T) and V(I) functions were measured with different parameters. The results of the measurements have confirmed the theory of conducting mechanism in the material. The percolation structure model has been built and described. As an application, a superconducting planar thick film transformer was planned and produced. Ten windings of the transformer were printed on one side of the alumina substrate and one winding was printed on the other side. The coupling between the two sides was possible through the substrate. The samples did not need special drying and firing parameters. After the preparation, the properties of the transformer were measured. The efficiency and the losses were determined. Finally, some fundamental advantages and problems of the process were discussed.

  2. Impact of thickness on microscopic and macroscopic properties of Fe-Te-Se superconductor thin films

    Directory of Open Access Journals (Sweden)

    N. Zhang

    2015-04-01

    Full Text Available A series of iron based Fe-Te-Se superconductor thin films depositing on 0.7wt% Nb-doped SrTiO3 at substrate temperatures in the 250°C -450°C range by pulsed laser ablation of a constituents well defined precursor FeTe0.55Se0.55 target sample. We study the possible growth mechanism and its influence on the superconductor properties. Experimental results indicate the superconductive and non-superconductive properties are modulated only by the thickness of the thin films through the temperature range. The films appear as superconductor whenever the thickness is above a critical value ∼30nm and comes to be non-superconductor below this value. Relative ratios of Fe to (Te+Se in the films retained Fe/(Te+Se1 for non-superconductor no matter what the film growth temperature was. The effect of film growth temperature takes only the role of modulating the ratio of Te/Se and improving crystallinity of the systems. According to the experimental results we propose a sandglass film growth mechanism in which the interfacial effect evokes to form a Fe rich area at the interface and Se or Te starts off a consecutive filling up process of chalcogenide elements defect sides, the process is significant before the film thickness reaches at ∼30nm.

  3. 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.

  4. Crossover from negative to positive magnetoresistance in superconductor/ferromagnet composites thick films

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, O. [Centro de Materiales, Facultad de Ingenieria, Universidad de Narino, Ciudad Universitaria Torobajo, Pasto (Colombia); Baca, E. [Grupo de Ingenieria de Nuevos Materiales, Departamento de Fisica, Universidad del Valle, A.A. 25360 Cali (Colombia); Fuchs, D. [Karlsruhe Institute of Technology, Institut fuer Festkoerperphysik, P.O. Box 3640, Karlsruhe (Germany); Moran, O., E-mail: omoranc@unal.edu.c [Laboratorio de Materiales Ceramicos y Vitreos, Departamento de Fisica, Universidad Nacional de Colombia, Sede Medellin, A.A. 568 Medellin (Colombia)

    2010-11-15

    Thick films of ((Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}){sub 0.95}/(LaSr{sub 0.7}Mn{sub 0.3}O{sub 3}){sub 0.05} [(Bi-2223){sub 0.95}(LSMO){sub 0.05}] composites were fabricated on (0 0 1)-oriented LaAlO{sub 3} substrates by a simple melting-quenching-annealing method and their structural, morphological and magnetoelectrical properties carefully studied. Analysis of the X-ray diffraction patterns suggested a highly oriented growth along the c-axis of LSMO. This preferred orientation, with the crystal c-axis being perpendicular to the plane of the substrate, was considered to be indicative of a textured growth mode. Electrical and magnetic measurements showed the presence of ferromagnetism and superconductivity in the composite at temperatures above room temperature and below T{approx}50 K, respectively. A clear crossover from negative to positive magnetoresistance was observed at {approx}80 K in a magnetic field as strong as 5 T.

  5. Percolation effect in thick film superconductors: Using a Bi(Pb)SrCaCuO based paste to prepare a superconducting planar transformer

    Science.gov (United States)

    Sali, Robert; Harsanyi, Gabor

    1995-01-01

    A thick film superconductor paste has been developed to study the properties of granulated superconductor materials, to observe the percolation effect and to confirm the theory of the conducting mechanism in the superconducting thick films. This paste was also applied to make a superconducting planar transformer. Due to the T(sub c) and advantageous current density properties the base of the past was chosen to be of Bi(Pb)SrCaCu) system. For contacts a conventional Ag/Pt paste was used. The critical temperature of the samples were between 110 K and 115 K depending on the printed layer thickness. The critical current density -at the boiling temperature of the liquid He- was between 200 - 300 A/sq cm. The R(T) and V(I) functions were measured with different parameters. The results of the measurements have confirmed the theory of conducting mechanism in the material. The percolation structure model has been built and described. As an application, a superconducting planar thick film transformer was planned and produced. Ten windings of the transformer were printed on one side of the alumina substrate and one winding was printed on the other side. The coupling between the two sides was possible through the substrate. The samples did not need special drying and firing parameters. After the preparation, the properties of the transformer were measured. The efficiency ans the losses were determined. Finally, some fundamental advantages and problems of the process were discussed.

  6. 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.

  7. Thick film hydrogen sensor

    Science.gov (United States)

    Hoffheins, Barbara S.; Lauf, Robert J.

    1995-01-01

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

  8. Two-dimensional superconductors with atomic-scale thickness

    Science.gov (United States)

    Uchihashi, Takashi

    2017-01-01

    Recent progress in two-dimensional superconductors with atomic-scale thickness is reviewed mainly from the experimental point of view. The superconducting systems treated here involve a variety of materials and forms: elemental metal ultrathin films and atomic layers on semiconductor surfaces; interfaces and superlattices of heterostructures made of cuprates, perovskite oxides, and rare-earth metal heavy-fermion compounds; interfaces of electric-double-layer transistors; graphene and atomic sheets of transition metal dichalcogenide; iron selenide and organic conductors on oxide and metal surfaces, respectively. Unique phenomena arising from the ultimate two dimensionality of the system and the physics behind them are discussed.

  9. Cathodoluminescence study of thin films of high Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Barkay, Z.; Azoulay, J.; Lereah, Y.; Dai, U.; Hess, N.; Racah, D.; Gruenbaum, E.; Deutscher, G. (School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 69978 Ramat Aviv (Israel))

    1990-10-22

    Cathodoluminescence (CL) of thin films of high {ital T}{sub {ital c}} superconductors was studied in the scanning electron microscope. The depth and the lateral locations of the different phases can be revealed. In thin films, unlike the bulk superconductors, the CL information can be obtained either from the film itself or the substrate by varying the primary beam energy. At high beam energy, substrate defects and slight thickness variations of a single high {ital T}{sub {ital c}} phase are observed. The resolution of the CL measurements improves at low temperatures.

  10. Preparation and Properties of High-T(sub c) Bi-Pb-Sr-Ca-Cu-O Thick Film Superconductors on YSZ Substrates

    Science.gov (United States)

    Hooker, Matthew W.

    1996-01-01

    An evaluation of four firing profiles was performed to determine the optimum processing conditions for producing high-T(sub c) Bi-Pb-Sr-Ca-Cu-O thick films on yttria-stabilized zirconia substrates. Using these four profiles, the effects of sintering temperatures of 830-850 C and soak times of 0.5 to 12 hours were examined. In this study, T-c, zero values of 100 K were obtained using a firing profile in which the films were sintered for 1.5 to 2 hours at 840 to 845 C and then quenched to room temperature. X-ray diffraction analyses of these specimens confirmed the presence of the high-T(sub c) phase. Films which were similarly fired and furnace cooled from the peak processing temperature exhibited a two-step superconductive transition to zero resistance, with T-c,zero values ranging from 85 to 92 K. The other firing profiles evaluated in this investigation yielded specimens which either exhibited critical transition temperatures below 90 K or did not exhibit a superconductive transition above 77 K.

  11. Fluxons in thin-film superconductor-insulator superlattices

    DEFF Research Database (Denmark)

    Sakai, S.; Bodin, P.; Pedersen, Niels Falsig

    1993-01-01

    films; in the limit of ultrathin superconductor films it may give a model for describing fluxon motion in layered high-Tc superconductors. Numerical examples of current versus voltage curves to be expected in such an experiment are presented. Journal of Applied Physics is copyrighted by The American...... Institute of Physics....

  12. Growth of layered superconductor β-PdBi2 films using molecular beam epitaxy

    Science.gov (United States)

    Denisov, N. V.; Matetskiy, A. V.; Tupkalo, A. V.; Zotov, A. V.; Saranin, A. A.

    2017-04-01

    Bulk β-PdBi2 layered material exhibits advanced properties and is supposed to be probable topological superconductor. We present a method based on molecular beam epitaxy that allows us to grow β-PdBi2 films from a single β-PdBi2 triple layer up to the dozens of triple layers, using Bi(111) film on Si(111) as a template. The grown films demonstrate structural, electronic and superconducting properties similar to those of bulk β-PdBi2 crystals. Ability to grow the β-PdBi2 films of desired thickness opens the promising possibilities to explore fascinating properties of this advanced material.

  13. Micro-droplets lubrication film thickness dynamics

    Science.gov (United States)

    Huerre, Axel; Theodoly, Olivier; Cantat, Isabelle; Leshansky, Alexander; Valignat, Marie-Pierre; Jullien, Marie-Caroline; MMN Team; LAI Team; IPR Team; Department of Chemical Engineering Team

    2014-11-01

    The motion of droplets or bubbles in confined geometries has been extensively studied; showing an intrinsic relationship between the lubrication film thickness and the droplet velocity. When capillary forces dominate, the lubrication film thickness evolves non linearly with the capillary number due to viscous dissipation between meniscus and wall. However, this film may become thin enough that intermolecular forces come into play and affect classical scalings. We report here the first experimental evidence of the disjoining pressure effect on confined droplets by measuring droplet lubrication film thicknesses in a microfluidic Hele-Shaw cell. We find and characterize two distinct dynamical regimes, dominated respectively by capillary and intermolecular forces. In the former case rolling boundary conditions at the interface are evidenced through film thickness dynamics, interface velocity measurement and film thickness profile.

  14. Superconductor-insulator quantum phase transition in disordered FeSe thin films.

    Science.gov (United States)

    Schneider, R; Zaitsev, A G; Fuchs, D; V Löhneysen, H

    2012-06-22

    The evolution of two-dimensional electronic transport with increasing disorder in epitaxial FeSe thin films is studied. Disorder is generated by reducing the film thickness. The extreme sensitivity of the films to disorder results in a superconductor-insulator transition. The finite-size scaling analysis in the critical regime based on the Bose-glass model strongly supports the idea of a continuous quantum phase transition. The obtained value for the critical-exponent product of approximately 7/3 suggests that the transition is governed by quantum percolation. Finite-size scaling with the same critical-exponent product is also substantiated when the superconductor-insulator transition is tuned with an applied magnetic field.

  15. Film thickness determination by grazing incidence diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Battiston, G. A.; Gerbasi, R. [CNR, Padua (Italy). Istituto di Chimica e Tecnologie Inorganiche e dei Materiali Avanzati

    1996-09-01

    Thin films deposited via MOCVD (Metal Organic Chemical Vapour Deposition) are layers in the thickness range of a few manometers to about ten micrometers. An understanding of the physics and chemistry of films is necessary for a better comprehension of the phenomena involved in the film deposition procedure and its optimisation. Together with the crystalline phase a parameter that must be determined is the thickness of the layer. In this work the authors present a method for the measurement of the film thickness. This procedure, based on diffraction intensity absorption of the X-rays, both incident and diffracted in passing through the layers, resulted quite simple, rapid and non-destructive.

  16. Preparation and characterization of superconductor thin films for application in printed circuit boards

    Energy Technology Data Exchange (ETDEWEB)

    Souza, G.A.; Carvalho, C.L.; Torsoni, G.B.; Rodrigues, V.D.; Souza, E.J.; Zadorosny, R. [UNESP, Ilha Solteira, SP (Brazil). Fac. de Engenharia. Grupo de Desenvolvimento e Aplicacoes de Materiais (GDAM)

    2011-07-01

    Full text: Since the discovery of high temperature superconductors (HTS) many studies have been performed, in terms to discover new materials with higher critical temperature and its potential applications. Technological advances have induced to use superconductor materials in the development of new devices that have higher processing speed, storage capacity and are miniaturized, what may imply in great evolution in the electronic area. Thinking about that advances and looking to supply some requirements, this work proposed to prepare a printed circuit board (PCB) with a superconductor thin film using an inexpensive and conventional photographic method. This work was divided in two steps: synthesis of the precursor solution and film preparation for superconductor printed circuit. In the preparation of superconductor thin film was considered to use the 2223 phase of the BSCCO system, which has been doped with Pb (BPSCCO) for stabilizing the same, and it presents a critical temperature around 110 K. This film was prepared from a precursor solution based on similar method developed by M. P. Pechini. The printed circuit was created by the photographic method of heat transfer which consisted of creation a circuit layout, with different dimensions and printed on photo paper (Epson S041140). The layout was transferred to the FR4 printed copper clad laminate was made with the household clothes iron. The precursor solution was deposited on Si substrate by spin-coating. The control of film thickness was performed by the deposition number that in this case was done five subsequent depositions to obtain an ideal thickness. Between each deposition the film was submitted to calcinations in order to eliminate organic matter. After that the film was submitted a heat treatment around 820 deg C / 5 minutes to obtain the expected superconducting phase and coupling and the grain growth. Film characterizations were made using optical microscopy, XRD and EDX, to check the dimensions and

  17. Effect of geometry on hydrodynamic film thickness

    Science.gov (United States)

    Brewe, D. E.; Hamrock, B. J.; Taylor, C. M.

    1978-01-01

    The influence of geometry on the isothermal hydrodynamic film separating two rigid solids was investigated. Pressure-viscosity effects were not considered. The minimum film thickness is derived for fully flooded conjunctions by using the Reynolds boundary conditions. It was found that the minimum film thickness had the same speed, viscosity, and load dependence as Kapitza's classical solution. However, the incorporation of Reynolds boundary conditions resulted in an additional geometry effect. Solutions using the parabolic film approximation are compared with those using the exact expression for the film in the analysis. Contour plots are shown that indicate in detail the pressure developed between the solids.

  18. Proximity effect of iron-based superconductor in conventional s-wave superconducting thin films

    Science.gov (United States)

    Groll, Nick; Proslier, Thomas; Koshelev, Alex; Stantev, Valentin; Chung, Duck-Young

    2012-02-01

    The proximity effect has been proposed as a mechanism to unambiguously identify the possible s±-state in iron-based superconductors.ootnotetextA. E. Koshelev, V. Stanev, Europhysics Letters, Vol. 96, 27014 (2011) With a thin s-wave superconductor atop a s±-superconductor it is suggested that the s-wave order parameter will couple to the s±-gaps differently, inducing a correction to the s-wave density of states that can be probed using electron tunneling spectroscopy. In this talk, we will present recent results of the superconducting proximity effect in s-wave MoGe thin films sputtered on top of bulk superconducting Ba0.6K0.4Fe2As2 (Tc=35K) pnictide. Electron tunneling spectroscopy measurements were performed for several MoGe film thicknesses using a homemade point contact setup. Finally, results will also be presented for similar measurements using two conventional s-wave superconductors.

  19. Nano-Hydroxyapatite Thick Film Gas Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Khairnar, Rajendra S.; Mene, Ravindra U.; Munde, Shivaji G.; Mahabole, Megha P. [School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606 (India)

    2011-12-10

    In the present work pure and metal ions (Co and Fe) doped hydroxyapatite (HAp) thick films have been successfully utilized to improve the structural, morphological and gas sensing properties. Nanocrystalline HAp powder is synthesized by wet chemical precipitation route, and ion exchange process is employed for addition of Co and Fe ions in HAp matrix. Moreover, swift heavy ion irradiation (SHI) technique is used to modify the surface of pure and metal ion exchanged HAp with various ion fluence. The structural investigation of pure and metal ion exchanged HAp thick films are carried out using X-ray diffraction and the presence of functional group is observed by means FTIR spectroscopy. Furthermore, surface morphology is visualized by means of SEM and AFM analysis. CO gas sensing study is carried out for, pure and metal ions doped, HAp thick films with detail investigation on operating temperature, response/recovery time and gas uptake capacity. The surface modifications of sensor matrix by SHI enhance the gas response, response/recovery and gas uptake capacity. The significant observation is here to note that, addition of Co and Fe in HAp matrix and surface modification by SHI improves the sensing properties of HAp films drastically resulting in gas sensing at relatively lower temperatures.

  20. Thin film superconductors and process for making same

    Science.gov (United States)

    Nigrey, P.J.

    1988-01-21

    A process for the preparation of oxide superconductors from high-viscosity non-aqueous solution is described. Solutions of lanthanide nitrates, alkaline earth nitrates and copper nitrates in a 1:2:3 stoichiometric ratio, when added to ethylene glycol containing citric acid solutions, have been used to prepare highly viscous non-aqueous solutions of metal mixed nitrates-citrates. Thin films of these compositions are produced when a layer of the viscous solution is formed on a substrate and subjected to thermal decomposition.

  1. High T(sub c) thin film superconductors: Preparation, patterning and characterization

    Science.gov (United States)

    Azoulay, J.

    A conventional oil-pumped vacuum system equipped with resistively heated tungsten boat sources was used for evaporation of bismuth- or yttrium-based cuprates for high T(sub c) thin film superconductors. A well-ground mixture with atomic proportions of bismuth, SrF2, CaF2 and copper for bismuth-based material, and of YF3, BaF2 and copper for yttrium-based material, was inserted into the boat and then resistively evaporated onto different substrates such as MgO, ZrO2 and SrTiO3 kept at room temperature. Yttrium-based thin films were found to have a better quality upon reduction of fluorine in the constituents. Thus, films prepared with an yttrium BaF2 and copper mixture show a metallic-like behavior, sharper transition and higher zero-resistance temperature as compared with that of films obtained by using a YF2 constiuent instead of yttrium. Bismuth-based thin films were found to lose bismuth during heat treatment unless the copper constiuent ended the evaporation process and was subsequently fully oxidized at 400 C. Bismuth-based patterned films were easily obtained by using a lift-off photolithographic method. Typical thickness of the films was measured to be about 0.5 micron after heat treatment.

  2. Properties of conductive thick-film inks

    Science.gov (United States)

    Holtze, R. F.

    1972-01-01

    Ten different conductive inks used in the fabrication of thick-film circuits were evaluated for their physical and handling properties. Viscosity, solid contents, and spectrographic analysis of the unfired inks were determined. Inks were screened on ceramic substrates and fired for varying times at specified temperatures. Selected substrates were given additional firings to simulate the heat exposure received if thick-film resistors were to be added to the same substrate. Data are presented covering the (1) printing characteristics, (2) solderability using Sn-63 and also a 4 percent silver solder, (3) leach resistance, (4) solder adhesion, and (5) wire bonding properties. Results obtained using different firing schedules were compared. A comparison was made between the various inks showing general results obtained for each ink. The changes in firing time or the application of a simulated resistor firing had little effect on the properties of most inks.

  3. Conduction Mechanisms in Thick Film Microcircuits

    Science.gov (United States)

    1975-12-01

    AREMCO 3100 Screen Printing Machine 53 3.11 Squeegee Design 55 3.12 Effect of Screen Printer Parameters on Filin Weight Deposited 59 3.13 Variation of...deviation of printing performance. This is discussed in greater detail sIfter the materials and machine are described. 3.5.2 Screening Material and...beyoni the range of monolithic technology can be satisfied by combining monolithic and thick film technologies. Design functions such as flexibility

  4. Flow fields in soap films: Relating viscosity and film thickness

    Science.gov (United States)

    Prasad, V.; Weeks, Eric R.

    2009-08-01

    We follow the diffusive motion of colloidal particles in soap films with varying h/d , where h is the thickness of the film and d is the diameter of the particles. The hydrodynamics of these films are determined by looking at the correlated motion of pairs of particles as a function of separation R . The Trapeznikov approximation [A. A. Trapeznikov, Proceedings of the 2nd International Congress on Surface Activity (Butterworths, London, 1957), p. 242] is used to model soap films as an effective two-dimensional (2D) fluid in contact with bulk air phases. The flow fields determined from correlated particle motions show excellent agreement with what is expected for the theory of 2D fluids for all our films where 0.6≤h/d≤14.3 , with the 2D shear viscosity matching that predicted by Trapeznikov. However, the parameters of these flow fields change markedly for thick films (h/d>7±3) . Our results indicate that three-dimensional effects become important for these thicker films, despite the flow fields still having a 2D character.

  5. Residual Stress Analysis in Thick Uranium Films

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, A M; Foreman, R J; Gallegos, G F

    2004-12-06

    Residual stress analysis was performed on thick, 1.0 to 25 {micro}m, depleted Uranium (DU) films deposited on an Al substrate by magnetron sputtering. Two distinct characterization techniques were used to measure substrate curvature before and after deposition. Stress evaluation was performed using the Benabdi/Roche equation, which is based on beam theory of a bi-layer material. The residual stress evolution was studied as a function of coating thickness and applied negative bias voltage (0-300V). The stresses developed were always compressive; however, increasing the coating thickness and applying a bias voltage presented a trend towards more tensile stresses and thus an overall reduction of residual stresses.

  6. Thickness Dependence of Resistivity and Optical Reflectance of ITO Films

    Institute of Scientific and Technical Information of China (English)

    GAO Mei-Zhen; JOB R; XUE De-Sheng; FAHRNER W R

    2008-01-01

    @@ Indium-tin-oxide (ITO) films deposited on crystalline silicon wafer and Coming glass are prepared by directcurrent magnetron sputtering method at room temperature with various thicknesses. The thickness dependences of structure, resistance and optical reflectance of ITO films are characterized. The results show that when the film thickness is less than 4Ohm, the resistivity and optical reflectance of the ITO tilm changes remarkably with thickness. The optoelectrical properties trend to stabilize when the thickness is over 55 nm. The GXRD result implies that the ITO film begins to crystallize if only the thickness is large enough.

  7. Determination of thin film refractive index and thickness by means of film phase thickness

    Science.gov (United States)

    Nenkov, Milen; Pencheva, Tamara

    2008-06-01

    A new approach for determination of refractive index dispersion n(λ) (the real part of the complex refractive index) and thickness d of thin films of negligible absorption and weak dispersion is proposed. The calculation procedure is based on determination of the phase thickness of the film in the spectral region of measured transmittance data. All points of measured spectra are included in the calculations. Barium titanate thin films are investigated in the spectral region 0.38-0.78 μm and their n(λ) and d are calculated. The approach is validated using Swanepoel's method and it is found to be applicable for relatively thin films when measured transmittance spectra have one minimum and one maximum only.

  8. Scaling analysis of field-tuned superconductor-insulator transition in two-dimensional tantalum thin films.

    Science.gov (United States)

    Park, Sungyu; Shin, Junghyun; Kim, Eunseong

    2017-02-20

    The superconductor-insulator (SI) transition in two-dimensional Ta thin films is investigated by controlling both film thickness and magnetic field. An intriguing metallic phase appears between a superconducting and an insulating phase within a range of film thickness and magnetic field. The temperature and electric field scaling analyses are performed to investigate the nature of the SI transition in the thickness-tuned metallic and superconducting samples. The critical exponents product of νz obtained from the temperature scaling analysis is found to be approximately 0.67 in the entire range of film thickness. On the other hand, an apparent discrepancy is measured in the product of ν(z + 1) by the electric filed analysis. The product values are found to be about 1.37 for the superconducting films and about 1.86 for the metallic films respectively. We find that the discrepancy is the direct consequence of electron heating that introduces additional dissipation channels in the metallic Ta films.

  9. Oriented Growth of PZT thick film embedded with PZT nanoparticles

    Institute of Scientific and Technical Information of China (English)

    DUAN Zhong-xia; YUAN Jie; ZHAO Quan-liang; LU Ran; CAO Mao-sheng

    2009-01-01

    This paper reports that dense and crack-free (100) oriented lead zirconate titanate (Pb(Zr0.52Ti0.48)O3,PZT) thick film embedded with PZT nanoparticles has been successfully fabricated on Pt/Cr/SiO2/Si substrate by using PT transition layer and PVP additive. The thick film possesses single-phase perovskite structure and perfectly (100) oriented. The (100) orientation degree of the PZT films strongly depended on annealing time and for the 4 μm-thick PZT film which was annealed at 700 ℃ for 5 min is the largest. The (100) orientation degree of the PZT thick film gradually strengthen along with the thickness of film decreasing. The 3 μm-thick PZT thick film which was annealed at 700 ℃ for 5 min has the strongest (100) orientation degree, which is 82. 3%.

  10. Thick film traps with an irregular film. Preparation and evaluation.

    Science.gov (United States)

    Kloskowski, Adam; Pettersson, Johan; Roeraade, Johan

    2004-05-07

    A new method for preparation of sorbent-based ultra-thick film traps for concentration of trace volatile components from gaseous matrices is described. The procedure is based on blowing a prepolymer (polydimethylsiloxane) through a capillary tube, forming an irregular film of stationary phase. Subsequently, the prepolymer is immobilized in a few seconds by heating to 200 degrees C. Evaluation of the performance of the new traps showed that the loss of efficiency, compared to regular smooth film traps is only on the order of 20-30%. In terms of breakthrough volume, this loss in performance is rather insignificant. The technology is extremely simple and allows a rapid and cheap production of a large number of ultra-thick film traps, even in non-specialized laboratories. The method can be applied to any type of cross-linkable stationary phase, thereby expanding the scope of sorbent-based trapping and preconcentration concept. Many applications are anticipated in trace and ultra-trace analysis in a wide range of fields, such as environmental chemistry, polymers, food and process analysis.

  11. Measurement Method of the Thickness Uniformity for Polymer Films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Several methods for investigating the thickness uniformity of polymer thin films are presented as well as their measurement principles. A comparison of these experimental methods is given.The cylindrical lightwave reflection method is found to can obtain the thickness distribution along a certain direction.It is a simple and suitable method to evaluate the film thickness uniformity.

  12. Superconductors

    CERN Document Server

    Narlikar, A V

    2014-01-01

    Superconductors is neither about basic aspects of superconductivity nor about its applications, but its mainstay is superconducting materials. Unusual and unconventional features of a large variety of novel superconductors are presented and their technological potential as practical superconductors assessed. The book begins with an introduction to basic aspects of superconductivity. The presentation is readily accessible to readers from a diverse range of scientific and technical disciplines, such as metallurgy, materials science, materials engineering, electronic and device engineering, and chemistry. The derivation of mathematical formulas and equations has been kept to a minimum and, wherever necessary, short appendices with essential mathematics have been added at the end of the text. The book is not meant to serve as an encyclopaedia, describing each and every superconductor that exists, but focuses on important milestones in their exciting development.

  13. Multiple High Voltage Pulse Stressing of Polymer Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    Busi Rambabu

    2014-01-01

    Full Text Available The purpose of this paper is to study high voltage interactions in polymer thick film resistors, namely, polyvinyl chloride- (PVC- graphite thick film resistors, and their applications in universal trimming of these resistors. High voltages in the form of impulses for various pulse durations and with different amplitudes have been applied to polymer thick film resistors and we observed the variation of resistance of these resistors with high voltages. It has been found that the resistance of polymer thick film resistors decreases in the case of higher resistivity materials and the resistance of polymer thick film resistor increases in the case of lower resistivity materials when high voltage impulses are applied to them. It has been also found that multiple high voltage pulse (MHVP stressing can be used to trim the polymer thick film resistors either upwards or downwards.

  14. Integrated thick-film nanostructures based on spinel ceramics.

    Science.gov (United States)

    Klym, Halyna; Hadzaman, Ivan; Shpotyuk, Oleh; Brunner, Michael

    2014-03-26

    Integrated temperature-humidity-sensitive thick-film structures based on spinel-type semiconducting ceramics of different chemical compositions and magnesium aluminate ceramics were prepared and studied. It is shown that temperature-sensitive thick-film structures possess good electrophysical characteristics in the region from 298 to 358 K. The change of electrical resistance in integrated thick-film structures is 1 order, but these elements are stable in time and can be successfully used for sensor applications.

  15. Integrated thick-film nanostructures based on spinel ceramics

    OpenAIRE

    Klym, Halyna; Hadzaman, Ivan; Shpotyuk, Oleh; Brunner, Michael

    2014-01-01

    Integrated temperature-humidity-sensitive thick-film structures based on spinel-type semiconducting ceramics of different chemical compositions and magnesium aluminate ceramics were prepared and studied. It is shown that temperature-sensitive thick-film structures possess good electrophysical characteristics in the region from 298 to 358 K. The change of electrical resistance in integrated thick-film structures is 1 order, but these elements are stable in time and can be successfully used for...

  16. Performance Comparison of Thin and Thick Film Microstrip Rejection Filters

    OpenAIRE

    Mandhare, M. M.; S.A. Gangal; M. S. Setty; Karekar, R. N.

    1988-01-01

    A performance comparison of microstripline circuits using thin and thick film techniques has been studied, in which a Microstrip rejection filter, in the X-band of microwaves, is used as test circuit. A thick film technique is capable of giving good adhesive films with comparable d.c. sheet resistivity, but other parameters such as open area (porosity), particle size, and edge definition are inferior to thin-film microstrip filters. Despite this drawback, the average value of transmission, tr...

  17. Use of buffy coat thick films in detecting malaria parasites in patients with negative conventional thick films

    Institute of Scientific and Technical Information of China (English)

    Chatnapa Duangdee; Noppadon Tangpukdee; Srivicha Krudsood; Polrat Wilairatana

    2012-01-01

    Objective: To determine the frequency of malaria parasite detection from the buffy coat blood ilms by using capillary tube in falciparum malaria patients with negative conventional thick ilms. Methods: Thirty six uncomplicated falciparum malaria patients confirmed by conventional thick and thin films were included in the study. The patients were treated with artemisinin combination therapy at Hospital for Tropical Diseases, Bangkok, Thailand for 28 day. Fingerpricks for conventional blood films were conducted every 6 hours until negative parasitemia, then daily fingerpricks for parasite checks were conducted until the patients were discharged from hospital. Blood samples were also concurrently collected in 3 heparinized capillary tubes at the same time of fingerpricks for conventional blood films when the prior parasitemia was negative on thin films and parasitemia was lower than 50 parasites/200 white blood cells by thick film. The first negative conventional thick films were compared with buffy coat thick films for parasite identification.Results:Out of 36 patients with thick films showing negative for asexual forms of parasites, buffy coat films could detect remaining 10 patients (27.8%) with asexual forms of Plasmodium falciparum. Conclusions: The study shows that buffy coat thick films are useful and can detect malarial parasites in 27.8% of patients whose conventional thick films show negative parasitemia.

  18. Influence of thickness on properties of plasticized oat starch films

    Directory of Open Access Journals (Sweden)

    Melicia Cintia Galdeano

    2013-08-01

    Full Text Available The aim of this study was to investigate the effect of thickness (between 80 and 120 µm on apparent opacity, water vapor permeability and mechanical properties (tensile and puncture of oat starch films plasticized with glycerol, sorbitol, glycerol:sorbitol mixture, urea and sucrose. Films were stored under 11, 57, 76 and 90% relative humidity (RH to study the mechanical properties. It was observed that the higher the thickness, the higher was the opacity values. Films without the plasticizer were more opaque in comparison with the plasticized ones. Glycerol:sorbitol films presented increased elongation with increasing thickness at all RH. Puncture force showed a strong dependence on the film thickness, except for the films plasticized with sucrose. In general, thickness did not affect the water permeability.

  19. Film thickness in grease lubricated slow rotating rolling bearings

    NARCIS (Netherlands)

    Morales-Espejel, G.E.; Lugt, Pieter Martin; Pasaribu, H.R.; Cen, H.

    2014-01-01

    Film thickness measurements in grease lubricated contacts are presented for different greases. The conditions used in the experiments are similar to the ones expected in fully-flooded slow rotating bearings. The results show that at very low speeds grease produces film thicknesses substantially thic

  20. Thickness dependence of vortex critical velocity in wide Nb films

    Energy Technology Data Exchange (ETDEWEB)

    Grimaldi, Gaia [CNR-INFM Regional Laboratory SuperMat, Via S. Allende, Baronissi, SA, I-84081 (Italy)], E-mail: grimaldi@sa.infn.it; Leo, Antonio; Nigro, Angela; Pace, Sandro; Cirillo, Carla; Attanasio, Carmine [CNR-INFM Regional Laboratory SuperMat, Via S. Allende, Baronissi, SA, I-84081 (Italy); Dipartimento di Fisica ' E.R. Caianiello' , Universita di Salerno, Via S. Allende, Baronissi, SA, I-84081 (Italy)

    2008-04-01

    Pulsed I-V measurements performed on wide Nb films of different thickness show the electronic instability, at high driving currents, predicted by Larkin and Ovchinnikov (LO). We find that the associated vortex critical velocity v* decreases with the film thickness, and its temperature and magnetic field dependences exhibit some discrepancies with respect to the LO theoretical results.

  1. Alginate-magnesium aluminum silicate composite films: effect of film thickness on physical characteristics and permeability.

    Science.gov (United States)

    Pongjanyakul, Thaned; Puttipipatkhachorn, Satit

    2008-01-04

    The different film thicknesses of the sodium alginate-magnesium aluminum silicate (SA-MAS) microcomposite films were prepared by varying volumes of the composite dispersion for casting. Effect of film thickness on thermal behavior, solid-state crystallinity, mechanical properties, water uptake and erosion, and water vapor and drug permeability of the microcomposite films were investigated. The film thickness caused a small change in thermal behavior of the films when tested using DSC and TGA. The crystallinity of the thin films seemed to increase when compared with the thick films. The thin films gave higher tensile strength than the thick films, whereas % elongation of the films was on the contrary resulted in the lower Young's modulus of the films when the film thickness was increased. This was due to the weaker of the film bulk, suggesting that the microscopic matrix structure of the thick films was looser than that of the thin films. Consequently, water uptake and erosion, water vapor permeation and drug diffusion coefficient of the thick films were higher than those of the thin films. The different types of drug on permeability of the films also showed that a positive charge and large molecule of drug, propranolol HCl, had higher lag time and lower diffusion coefficient that acetaminophen, a non-electrolyte and small molecule. This was because of a higher affinity of positive charge drug on MAS in the films. The findings suggest that the evaporation rate of solvent in different volumes of the composite dispersion used in the preparation method could affect crystallinity and strength of the film surface and film bulk of the microcomposite films. This led to a change in water vapor and drug permeability of the films.

  2. Spray pyrolysis for high T{sub c} superconductors films

    Energy Technology Data Exchange (ETDEWEB)

    Odier, P [Laboratoire de Cristallographie, CNRS, 25 Avenue des Martyrs, BP 166, 38042 Grenoble Cedex (France); Supardi, Z [Physics Department, Universitas Negeri Surabaya, 60231 (Indonesia); De-Barros, D [Laboratoire de Cristallographie, CNRS, 25 Avenue des Martyrs, BP 166, 38042 Grenoble Cedex (France); Vergnieres, L [Laboratoire de Cristallographie, CNRS, 25 Avenue des Martyrs, BP 166, 38042 Grenoble Cedex (France); Ramirez-Castellanos, J [Departamento de Quimica Inorganica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040-Madrid (Spain); Gonzales-Calbet, J M [Departamento de Quimica Inorganica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040-Madrid (Spain); Vallet-Regi, M [Departamento de Quimica Inorganica y Bioinorganica, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid (Spain); Villard, C [CRTBT, 25 Avenue des Martyrs, BP 166, 38042 Grenoble Cedex (France); Peroz, Ch [CRTBT, 25 Avenue des Martyrs, BP 166, 38042 Grenoble Cedex (France); Weiss, F [Laboratoire des Materiaux et du Genie Physique (LMGP), INPG, 38406 St Martin d' Heres Cedex (France)

    2004-11-01

    Spray pyrolysis at high temperature is reviewed and applied to the formation of epitaxial thick layers of YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO). The necessary conditions to enhance the texture quality and the critical current density are discussed. High critical current densities, over 1.0 MA cm{sup -2} (at 77 K, self-field), are reported, making this technique very promising for low cost applications. This emphasizes the need for more comprehensive studies regarding the chemical phenomena involved in film deposition by spray pyrolysis at high temperature, especially those concerning local equilibrium and reactions occurring in the area involved in the deposition.

  3. Film-thickness Error Analysis of Optical Disk Systems

    Institute of Scientific and Technical Information of China (English)

    WANG Yang; GU Donghong; GAN Fuxi

    2001-01-01

    It is difficult to exactly control the film thickness of optical disk multilayer in the actual coating process. The thickness error becomes a main factor affecting the optical characters of the film system. The thickness error′s sensitivity factor of dielectric optical multilayer is derived from the optical matrix in this paper. The effect of the thickness error on the reflectivity or reflectivity contrast of the optical disk multilayer is analyzed with a numerical calculation. The sensitivities to thickness error for different layers or in different film-thickness ranges are compared and discussed. A sketchy method defining allowable thickness error is given. Some experimental results verify the applicability of our theoretical analysis.

  4. Thick antiwear films in elastohydrodynamic contacts. I. Film growth in rolling/sliding EHD contacts

    Energy Technology Data Exchange (ETDEWEB)

    Lacey, I.N.; Kelsall, G.H.; Spikes, H.A.; Macpherson, P.B.

    1986-07-01

    The formation and characteristics of thick films in elastohydrodynamic (EHD) contacts using pure phosphonate additives are described. Several alkyl and aryl group, pure phosphonate additives were added to rolling/sliding EHD contacts; the performance of the phosphonate additives is evaluated. It is observed that all phosphonates formed thick films from base oil solutions in rolling EHD contacts; the films have a thickness greater than a half a micron, withstand up to 10 percent sliding, and are formed in the presence of other additives. The effects of phosphonate group and temperature on the rate of film formation are investigated. The chemical properties of the viscous reaction product and the thick films formed by the phosphonates are analyzed. The reaction product and films consist of an iron-phosphate-monoester polymer with the phosphate acting as a bridge between iron(III) species. The use of the thick antiwear films to increase specific film thickness in EHD lubrication is discussed. 31 references.

  5. Advantages of PZT thick film for MEMS sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Lou-Moller, R.; Hansen, K.;

    2010-01-01

    For all MEMS devices a high coupling between the mechanical and electrical domain is desired. Figures of merit describing the coupling are important for comparing different piezoelectric materials. The existing figures of merit are discussed and a new figure of merit is introduced for a fair...... comparison of piezoelectric thin and thick films based MEMS devices, as cantilevers, beams, bridges and membranes. Simple analytical modeling is used to define the new figure of merit. The relevant figure of merits is compared for the piezoelectric material of interest for MEMS applications: ZnO, AIN, PZT...... thin film and PZT thick film. It is shown that MEMS sensors with the PZT thick film TF2100 from InSensor A/S have potential for significant higher voltage sensitivities compared to PZT thin film base MEMS sensors when the total thickness of the MEMS cantilever, beam, bridge or membrane is high...

  6. Ba2ErNbO6: A new perovskite ceramic substrate for Bi(2223) superconducting thick films (c(0) = 110 K)

    Indian Academy of Sciences (India)

    S U K Nair; P R S Warriar; J Koshy

    2005-02-01

    Barium erbium niobate (Ba2ErNbO6) has been developed as a new substrate for (Bi,Pb)2Sr2Ca2Cu3O [Bi(2223)] superconductor film. Ba2ErNbO6 (BENO) has a cubic perovskite structure with lattice constant, = 8.318 Å. The Bi(2223) superconductor does not show any detectable chemical reaction with BENO even under extreme processing conditions. Dip coated Bi (2223) thick film, Ba2ErNbO6 substrate, gave a c (0) of 110 K and current density of ∼ 4 × 103 A cm-2 at 77 K and zero magnetic field.

  7. Barium titanate thick films prepared by screen printing technique

    Directory of Open Access Journals (Sweden)

    Mirjana M. Vijatović

    2010-06-01

    Full Text Available The barium titanate (BaTiO3 thick films were prepared by screen printing technique using powders obtained by soft chemical route, modified Pechini process. Three different barium titanate powders were prepared: i pure, ii doped with lanthanum and iii doped with antimony. Pastes for screen printing were prepared using previously obtained powders. The thick films were deposited onto Al2O3 substrates and fired at 850°C together with electrode material (silver/palladium in the moving belt furnace in the air atmosphere. Measurements of thickness and roughness of barium titanate thick films were performed. The electrical properties of thick films such as dielectric constant, dielectric losses, Curie temperature, hysteresis loop were reported. The influence of different factors on electrical properties values was analyzed.

  8. Thickness-dependent spontaneous dewetting morphology of ultrathin Ag films.

    Science.gov (United States)

    Krishna, H; Sachan, R; Strader, J; Favazza, C; Khenner, M; Kalyanaraman, R

    2010-04-16

    We show here that the morphological pathway of spontaneous dewetting of ultrathin Ag films on SiO2 under nanosecond laser melting is dependent on film thickness. For films with thickness h of 2 nm intermolecular forces, we have estimated the morphological transition thickness for the intermolecular forces for Ag on SiO2. The theory predictions agree well with observations for Ag. These results show that it is possible to form a variety of complex Ag nanomorphologies in a consistent manner, which could be useful in optical applications of Ag surfaces, such as in surface enhanced Raman sensing.

  9. High Tc thin film superconductors: preparation, patterning and characterization. [Y-Ba-Cu-O; Bi-Sr-Ca-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, J. (Center for Tech. Education, Holon (Israel) Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv Univ. (Israel))

    1991-12-10

    A conventional oil-pumped vacuum system equipped with resistively heated tungsten boat sources was used for evaporation of bismuth- or yttrium-based cuprates for high Tc thin films superconductors. A well-ground mixture with atomic proportions of bismuth, SrF{sub 2}, CaF{sub 2} and copper for bismuth-based material, and of YF{sub 3}, BaF{sub 2} and copper for yttrium-based material, was inserted into the boat and then resistively evaporated onto different substrates such as MgO, ZrO{sub 2} and SrTiO{sub 3} kept at room temperature. Yttrium-based thin films were found to have a better quality upon reduction of fluorine in the constituents. Thus, films prepared with an yttrium BaF{sub 2} and copper mixture show a metallic-like behaviour, sharper transition and higher zero-resistance temperature as compared with that of films obtained by using a YF{sub 2} constituent instead of yttrium. Bismuth-based thin films were found to lose bismuth during heat treatment unless the copper constituent ended the evaporation process and was subsequently fully oxidized at 400degC. Bismuth-based patterned films were easily obtained by using a lift-off photolithographic method. Typical thickness of the films was measured to be about 0.5 {mu}m after heat treatment. (orig.).

  10. Refractive index of nanoscale thickness films measured by Brewster refractometry

    CERN Document Server

    Tikhonov, E A; Malyukin, Yu V

    2015-01-01

    It is shown that reflective laser refractometery at Brewster angle can be usefull for precision measurements of refractive indexes (RI) in the transparency band of various films of nanoscale thickness. The RI measurements of nanoscale porous film on the basis of gadolinium orthosilicate and quartz have been carried out as first experience. It is shown that surface light scattering in such films that is connected with clustering of nanoscale pores can decrease the accuracy of the RI measurements at Brewster angle. Estimated physical dependence RI stipulated by the film thickness reduction (3D-2D transition) in the range of (20-160)nm has not been not detected.

  11. Liquid film thickness measurement by two-line TDLAS

    Science.gov (United States)

    Yang, Huinan; Chen, Jun; Cai, Xiaoshu; Greszik, Daniel; Dreier, Thomas; Schulz, Christof

    2014-04-01

    A fiber-based two-line tunable diode-laser absorption sensor with two near-infrared (NIR) distributed-feedback (DFB) diode lasers at ˜1.4 μm was used for non-intrusive time-resolved liquid water film thickness measurement. When probing the liquid film at two different wavelengths with significantly different absorption cross-sections, the additional signal losses due to surface fowling, reflection and beam steering can be eliminated. In this work, the evaporation process of a liquid film on transparent quartz plate was tracked and large fluctuations of film thickness were found at the end of the evaporation.

  12. Liquid film thickness measurement by two-line TDLAS

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Huinan [School of Energy and Power Engineering, University of Shanghai for Science and Technology, 200093, Shanghai, China and IVG, University of Duisburg-Essen, 47057, Duisburg (Germany); Chen, Jun; Cai, Xiaoshu [School of Energy and Power Engineering, University of Shanghai for Science and Technology, 200093, Shanghai (China); Greszik, Daniel; Dreier, Thomas; Schulz, Christof [IVG, University of Duisburg-Essen, 47057, Duisburg (Germany)

    2014-04-11

    A fiber-based two-line tunable diode-laser absorption sensor with two near-infrared (NIR) distributed-feedback (DFB) diode lasers at ∼1.4 μm was used for non-intrusive time-resolved liquid water film thickness measurement. When probing the liquid film at two different wavelengths with significantly different absorption cross-sections, the additional signal losses due to surface fowling, reflection and beam steering can be eliminated. In this work, the evaporation process of a liquid film on transparent quartz plate was tracked and large fluctuations of film thickness were found at the end of the evaporation.

  13. Self-assembled film thickness determination by focused ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Dejeu, J. [Institut UTINAM, UMR 6213 CNRS-UFC - equipe Materiaux et Surfaces Structures, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France)], E-mail: jerome.dejeu@univ-fcomte.fr; Salut, R. [Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Centrale MIMENTO, Universite de Franche-Comte, 32 avenue de l' Observatoire - 25044 Besancon Cedex (France); Spajer, M. [Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Centrale MIMENTO, Universite de Franche-Comte, 32 avenue de l' Observatoire - 25044 Besancon Cedex (France); Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Departement d' Optique, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France); Membrey, F.; Foissy, A. [Institut UTINAM, UMR 6213 CNRS-UFC - equipe Materiaux et Surfaces Structures, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France); Charraut, D. [Institut FEMTO-ST, UMR 6174 CNRS-UFC-UTBM-ENSMM, Departement d' Optique, Universite de Franche-Comte, UFR Sciences et Techniques, 16 route de Gray - 25030 Besancon Cedex (France)

    2008-06-30

    The thickness evolution of multilayer film is investigated by focused ion beam (FIB) in the domain of polymer multilayers. This method, currently used in the modification and the characterization of integrated circuits, proves it is possible to determine the polymer film thickness. Sample cutting and its observation of the cross-section are performed in the FIB without leaving the vacuum chamber. Two main conclusions can be drawn: (1) the roughness of the film increases with the number of layer deposit, (2) the film growth changes from nonlinear (called exponential) to linear beyond 300 nm (70 layers)

  14. Development of solid state thick film zirconia oxygen gas sensors.

    OpenAIRE

    Ioannou, Andreas Stylianou

    1992-01-01

    Aspects relating to and including the development of thick film amperometric zirconia oxygen sensors were investigated. These devices, which were operated in the range 550-950°C, had a laminated structure in which a cathode, an electrolyte and an anode were printed, in that order, onto a planar alumina substrate. The anode and electrolyte were porous and during sensor Operation also acted as a diffusion barrier, restricting the rate of oxygen diffusion to the cathode. A thick film platinum he...

  15. Electrophoretic deposition and constrained sintering of strontium titanate thick films

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Luís; Vilarinho, Paula M., E-mail: paula.vilarinho@ua.pt; Senos, Ana M.R.

    2015-01-15

    Thick films of functional oxides are currently substituting counterparts bulk ceramics, as in the case of low loss dielectrics. For SrTiO{sub 3} (ST) based compositions it is demonstrated that electrophoretic deposition (EPD), using acetone as a suspension media with iodine addition, is a suitable technology to fabricate 12 μm thick films. The microstructural analysis of the films sintered at 1500 °C shows that highly densified microstructures can be obtained and, by slightly varying the Sr/Ti stoichiometry in the powder composition, increased densification and grain size and enlargement of the distribution with decreasing Sr/Ti ratio can be observed. In spite of the high densification of the films, it is also demonstrated that due to the constraint imposed by the substrate a smaller grain size is observed in thick films as compared to equivalent bulk ceramics. In addition, a preferential vertical pore orientation is observed in ST thick films. These results may have broad implications if one considers that the dielectric losses and dielectric tunability is affected by pore orientation, since it affects the electric field distribution. - Highlights: • Nonstoichiometry effect on microstructure of constrained sintered thick films and bulk is similar. • Increased densification and grain size and enlargement of distribution with decreasing Sr/Ti ratio. • Independent of Sr/Ti ratio smaller grain size for thick films compared to ceramics. • Preferential vertical pore orientation for constrained sintering of thick films. • Anisotropic porosity as tailoring factor to engineer permittivity and tunability.

  16. Electrical properties of Y-Ba-Na-Cu-O high Tc superconductors thin films

    Energy Technology Data Exchange (ETDEWEB)

    Verdyan, A. (Center for Theoretical Education Holon (Israel) Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv Univ. (Israel)); Lapsker, I. (Center for Theoretical Education Holon (Israel) Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv Univ. (Israel)); Azoulay, J. (Center for Theoretical Education Holon (Israel) Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv Univ. (Israel))

    1993-04-20

    Y-Ba-Na-Cu-O high Tc superconductors thin films deposited on MgO substrate by resistive evaporation technique were found to have improved electrical properties as compared to pure Y-Ba-Cu-O thin films similarly prepared. A simple conventional inexpensive vacuum system housing a single resistively tungsten heated source was used for the deposition. Pulverized mixture of Y, BaF[sub 2], NaF and Cu in the appropriate atomic proportion was evaporated onto the substrates whose temperature was held constant at 400 C during the evaporation. In situ heat treatment has been carried out at 700 C under oxygen partial pressure of 7 pa. The films thus obtained were found to have the normal superconductors orthorhombic phase at room temperature without any further ex situ heat treatment. The films were characterized and analyzed by X-ray diffraction auger election spectroscopy and four point dc electrical measurements. (orig.)

  17. Electrical properties of Y-Ba-Na-Cu-O high Tc superconductors thin films

    Science.gov (United States)

    Verdyan, A.; Lapsker, I.; Azoulay, J.; Sackler, Raymond; Sackler, Beverly

    1993-04-01

    Y-Ba-Na-Cu-O high Tc superconductors thin films deposited on MgO substrate by resistive evaporation technique were found to have improved electrical properties as compared to pure Y-Ba-Cu-O thin films similarly prepared. A simple conventional inexpensive vacuum system housing a single resistively tungsten heated source was used for the deposition. Pulverized mixture of Y, BaF 2, NaF and Cu in the appropriate atomic proportion was evaporated onto the substrates whose temperature was held constant at 400°C during the evaporation. In situ heat treatment has been carried out at 700°C under oxygen partial pressure of 7 pa. The films thus obtained were found to have the normal superconductors orthorhombic phase at room temperature without any further ex situ heat treatment. The films were characterized and analyzed by x-ray diffraction auger electron spectroscopy and four point dc electrical measurements.

  18. Sputtering of Thick Deuterium Films by KeV Electrons

    DEFF Research Database (Denmark)

    Thestrup Nielsen, Birgitte; Svendsen, Winnie Edith; Schou, Jørgen;

    1994-01-01

    Sputtering of thick films of solid deuterium up to several μm by keV electrons is reported for the first time. The sputtering yield increases within a narrow range of thicknesses around 1.6 μm by about 2 orders of magnitude for 1.5 keV electrons. A similar behavior has not been observed for ion...

  19. Electronic evidence of an insulator-superconductor crossover in single-layer FeSe/SrTiO3 films.

    Science.gov (United States)

    He, Junfeng; Liu, Xu; Zhang, Wenhao; Zhao, Lin; Liu, Defa; He, Shaolong; Mou, Daixiang; Li, Fangsen; Tang, Chenjia; Li, Zhi; Wang, Lili; Peng, Yingying; Liu, Yan; Chen, Chaoyu; Yu, Li; Liu, Guodong; Dong, Xiaoli; Zhang, Jun; Chen, Chuangtian; Xu, Zuyan; Chen, Xi; Ma, Xucun; Xue, Qikun; Zhou, X J

    2014-12-30

    In high-temperature cuprate superconductors, it is now generally agreed that superconductivity is realized by doping an antiferromagnetic Mott (charge transfer) insulator. The doping-induced insulator-to-superconductor transition has been widely observed in cuprates, which provides important information for understanding the superconductivity mechanism. In the iron-based superconductors, however, the parent compound is mostly antiferromagnetic bad metal, raising a debate on whether an appropriate starting point should go with an itinerant picture or a localized picture. No evidence of doping-induced insulator-superconductor transition (or crossover) has been reported in the iron-based compounds so far. Here, we report an electronic evidence of an insulator-superconductor crossover observed in the single-layer FeSe film grown on a SrTiO3 substrate. By taking angle-resolved photoemission measurements on the electronic structure and energy gap, we have identified a clear evolution of an insulator to a superconductor with increasing carrier concentration. In particular, the insulator-superconductor crossover in FeSe/SrTiO3 film exhibits similar behaviors to that observed in the cuprate superconductors. Our results suggest that the observed insulator-superconductor crossover may be associated with the two-dimensionality that enhances electron localization or correlation. The reduced dimensionality and the interfacial effect provide a new pathway in searching for new phenomena and novel superconductors with a high transition temperature.

  20. Stoichiometry and thickness dependence of superconducting properties of niobium nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Beebe, Melissa R., E-mail: mrbeebe@email.wm.edu; Beringer, Douglas B.; Burton, Matthew C.; Yang, Kaida; Lukaszew, R. Alejandra [Department of Physics, The College of William & Mary, Small Hall, 300 Ukrop Way, Williamsburg, Virginia 23185 (United States)

    2016-03-15

    The current technology used in linear particle accelerators is based on superconducting radio frequency (SRF) cavities fabricated from bulk niobium (Nb), which have smaller surface resistance and therefore dissipate less energy than traditional nonsuperconducting copper cavities. Using bulk Nb for the cavities has several advantages, which are discussed elsewhere; however, such SRF cavities have a material-dependent accelerating gradient limit. In order to overcome this fundamental limit, a multilayered coating has been proposed using layers of insulating and superconducting material applied to the interior surface of the cavity. The key to this multilayered model is to use superconducting thin films to exploit the potential field enhancement when these films are thinner than their London penetration depth. Such field enhancement has been demonstrated in MgB{sub 2} thin films; here, the authors consider films of another type-II superconductor, niobium nitride (NbN). The authors present their work correlating stoichiometry and superconducting properties in NbN thin films and discuss the thickness dependence of their superconducting properties, which is important for their potential use in the proposed multilayer structure. While there are some previous studies on the relationship between stoichiometry and critical temperature T{sub C}, the authors are the first to report on the correlation between stoichiometry and the lower critical field H{sub C1}.

  1. Influence of superconductor film composition on adhesion strength of coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Kesgin, Ibrahim; Khatri, Narayan; Liu, Yuhao; Delgado, Louis; Galstyan, Eduard; Selvamanickam, Venkat

    2015-11-20

    The effect of high temperature superconductor (HTS) film composition on the adhesion strength of rare- earth barium copper oxide coated conductors (CCs) has been studied. It has been found that the mechanical integrity of the superconductor layer is very susceptible to the defects especially those along the ab plane, probably due to the weak interfaces between the defects and the matrix. Gd and Y in the standard composition were substituted with Sm and the number of in-plane defects was drastically reduced. Consequently, a four-fold increase in adhesion or peeling strength in Sm-based CCs was achieved compared to the standard GdYBCO samples.

  2. Thick REBaCuO superconducting films through single-coating of low-fluorine metallorganic solution

    Science.gov (United States)

    Boubeche, M.; Cai, C. B.; Jian, H. B.; Li, M. J.; Yang, W. T.; Liu, Z. Y.; Bai, C. Y.

    2016-10-01

    A high critical current Ic is crucial for the application of high temperature superconductors YBa2Cu3O7-δ in energy efficient power devices and wires. In this paper we report the fabrication of thick (YGd)1.3Ba2Cu3O7-x films on a metal substrate using low-fluorine metal organic deposition method. The effects of the film thickness on the microstructure, texture and superconductivity properties of the films were evaluated. In order to increase the film thicknesses by single coating, the influence of withdrawal speed during the dip coating on resulting thickness are investigated with the other processing parameters fixed. It is revealed that there is a maximum thickness for a certain starting solution. Here we used 3 different solutions, Conventional Low Fluorine solutions with 2 M and 2.5 M, and super low-fluorine solution with 2.5 M. The maximum thicknesses of about 710 nm, 1280 nm and 1460 nm were obtained, respectively.

  3. Changes in the temperature-dependent specific volume of supported polystyrene films with film thickness

    Science.gov (United States)

    Huang, Xinru; Roth, Connie B.

    2016-06-01

    Recent studies have measured or predicted thickness-dependent shifts in density or specific volume of polymer films as a possible means of understanding changes in the glass transition temperature Tg(h) with decreasing film thickness with some experimental works claiming unrealistically large (25%-30%) increases in film density with decreasing thickness. Here we use ellipsometry to measure the temperature-dependent index of refraction of polystyrene (PS) films supported on silicon and investigate the validity of the commonly used Lorentz-Lorenz equation for inferring changes in density or specific volume from very thin films. We find that the density (specific volume) of these supported PS films does not vary by more than ±0.4% of the bulk value for film thicknesses above 30 nm, and that the small variations we do observe are uncorrelated with any free volume explanation for the Tg(h) decrease exhibited by these films. We conclude that the derivation of the Lorentz-Lorenz equation becomes invalid for very thin films as the film thickness approaches ˜20 nm, and that reports of large density changes greater than ±1% of bulk for films thinner than this likely suffer from breakdown in the validity of this equation or in the difficulties associated with accurately measuring the index of refraction of such thin films. For larger film thicknesses, we do observed small variations in the effective specific volume of the films of 0.4 ± 0.2%, outside of our experimental error. These shifts occur simultaneously in both the liquid and glassy regimes uniformly together starting at film thicknesses less than ˜120 nm but appear to be uncorrelated with Tg(h) decreases; possible causes for these variations are discussed.

  4. Thickness of residual wetting film in liquid-liquid displacement

    Science.gov (United States)

    Beresnev, Igor; Gaul, William; Vigil, R. Dennis

    2011-08-01

    Core-annular flow is common in nature, representing, for example, how streams of oil, surrounded by water, move in petroleum reservoirs. Oil, typically a nonwetting fluid, tends to occupy the middle (core) part of a channel, while water forms a surrounding wall-wetting film. What is the thickness of the wetting film? A classic theory has been in existence for nearly 50 years offering a solution, although in a controversial manner, for moving gas bubbles. On the other hand, an acceptable, experimentally verified theory for a body of one liquid flowing in another has not been available. Here we develop a hydrodynamic, testable theory providing an explicit relationship between the thickness of the wetting film and fluid properties for a blob of one fluid moving in another, with neither phase being gas. In its relationship to the capillary number Ca, the thickness of the film is predicted to be proportional to Ca2 at lower Ca and to level off at a constant value of ˜20% the channel radius at higher Ca. The thickness of the film is deduced to be approximately unaffected by the viscosity ratio of the fluids. We have conducted our own laboratory experiments and compiled experimental data from other studies, all of which are mutually consistent and confirm the salient features of the theory. At the same time, the classic law, originally deduced for films surrounding moving gas bubbles but often believed to hold for liquids as well, fails to explain the observations.

  5. Determination of hydration film thickness using atomic force microscopy

    Institute of Scientific and Technical Information of China (English)

    PENG Changsheng; SONG Shaoxian; GU Qingbao

    2005-01-01

    Dispersion of a solid particle in water may lead to the formation of hydration film on the particle surface, which can strongly increase the repulsive force between the particles and thus strongly affect the stability of dispersions. The hydration film thickness, which varies with the variation of property of suspension particles, is one of the most important parameters of hydration film, and is also one of the most difficult parameters that can be measured accurately. In this paper, a method, based on force-distance curve of atomic force microscopy, for determining the hydration film thickness of particles is developed. The method utilizes the difference of cantilever deflection before, between and after penetrating the hydration films between tip and sample, which reflect the difference of slope on the force-distance curve. 3 samples, mica, glass and stainless steel, were used for hydration thickness determination, and the results show that the hydration film thickness between silicon tip and mica, glass and stainless steel are 30.0(2.0, 29.0(1.0 and 32.5(2.5 nm, respectively.

  6. Epitaxial thin film growth and properties of unconventional oxide superconductors. Cuprates and cobaltates

    Energy Technology Data Exchange (ETDEWEB)

    Krockenberger, Y.

    2006-07-01

    The discovery of high-temperature superconductors has strongly driven the development of suited thin film fabrication methods of complex oxides. One way is the adaptation of molecular beam epitaxy (MBE) for the growth of oxide materials. Another approach is the use of pulsed laser deposition (PLD) which has the advantage of good stoichiometry transfer from target to the substrate. Both techniques are used within this thesis. Epitaxial thin films of new materials are of course needed for future applications. In addition, the controlled synthesis of thin film matter which can be formed far away from thermal equilibrium allows for the investigation of fundamental physical materials properties. (orig.)

  7. Thick-film materials for silicon photovoltaic cell manufacture

    Science.gov (United States)

    Field, M. B.

    1977-01-01

    Thick film technology is applicable to three areas of silicon solar cell fabrication; metallization, junction formation, and coating for protection of screened ohmic contacts, particularly wrap around contacts, interconnection and environmental protection. Both material and process parameters were investigated. Printed ohmic contacts on n- and p-type silicon are very sensitive to the processing parameters of firing time, temperature, and atmosphere. Wrap around contacts are easily achieved by first printing and firing a dielectric over the edge and subsequently applying a low firing temperature conductor. Interconnection of cells into arrays can be achieved by printing and cofiring thick film metal pastes, soldering, or with heat curing conductive epoxies on low cost substrates. Printed (thick) film vitreous protection coatings do not yet offer sufficient optical uniformity and transparency for use on silicon. A sprayed, heat curable SiO2 based resin shows promise of providing both optical matching and environmental protection.

  8. MEMS-based thick film PZT vibrational energy harvester

    DEFF Research Database (Denmark)

    Lei, Anders; Xu, Ruichao; Thyssen, Anders

    2011-01-01

    We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using a mechan......We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using...... a mechanical front side protection of an SOI wafer with screen printed PZT thick film. The fabricated harvester device produces 14.0 μW with an optimal resistive load of 100 kΩ from 1g (g=9.81 m s-2) input acceleration at its resonant frequency of 235 Hz....

  9. Formation and physical properties of YBCO thick films grown by using the electrophoretic deposition method

    CERN Document Server

    Kim, U J; Kim, Y C; Han, S K; Kang, K Y

    1999-01-01

    Thick films of the YBa sub 2 Cu sub 3 O subgamma sub - subdelta (YBCO) superconductor were prepared by using the electrophoretic deposition technique and a flexible wire as the substrate. The transition temperature of the wires was 91 K, the intragranular magnetic critical current density J sub c sub g sup m sup a sup g was about 10 sup 5 A/cm sup 2 at 77 K in a weak field, and the transport J sub c sup t sup r sup a sup n sup s was about 365 A/cm sup 2 at 77 K. We calculated the intergranular magnetic critical current J sub c sub J sup m sup a sup g and the activation energy from the AC-susceptibility measurements, and their values were about 444 A/cm sup 2 at 77 K and 2.02 eV, respectively.

  10. Effect of layer thickness on the superconducting properties in ultrathin Pb films

    Science.gov (United States)

    Durajski, A. P.

    2015-09-01

    Recently, superconductivity was found in one atomic layer of Pb film, promising a new field of research where superconductors can be studied on the atomic level. In the presented paper, we report a theoretical study of the superconductivity in ultrathin Pb films consisting of five to ten monolayers. Using the strong coupling Eliashberg formalism we reproduced the experimental values of critical temperature (TC) and we estimated the superconducting energy gap (Δ (0)), thermodynamic critical field (HC) and the specific heat jump at critical temperature (Δ C≤ft({T}{{C}}\\right)\\equiv {C}{{S}}≤ft({T}{{C}}\\right)-{C}{{N}}≤ft({T}{{C}}\\right)) for a wide range of film thicknesses. In these systems, we found an oscillatory behaviour of the above thermodynamic properties modulated by quantum size effects. Moreover, the large values of 2Δ (0){/k}{{B}}{T}{{C}} and Δ C≤ft({T}{{C}}\\right)/{C}{{N}}≤ft({T}{{C}}\\right), and the small values of {T}{{C}}{C}{{N}}≤ft({T}{{C}}\\right)/{H}{{C}}2(0) prove that the thermodynamic properties of Pb films cannot be correctly described using the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity due to the strong coupling and retardation effects.

  11. Grain size and film thickness effect on the thermal expansion coefficient of FCC metallic thin films.

    Science.gov (United States)

    Hwang, Seulgi; Kim, Youngman

    2011-08-01

    Thin films are used in wide range of applications in industry, such as solar cells and LEDs. When thin films are deposited on substrates, various stresses are generated due to the mechanical difference between the film and substrate. These stresses can cause defects, such as cracking and buckling. Therefore, knowledge of the mechanical properties is important for improving their reliability and stability. In this study, the thermal expansion coefficient of FCC metallic thin films, such as Ag and Cu, which have different grain sizes and thicknesses, were calculated using the thermal cycling method. As a result, thermal expansion coefficient increased with increasing grain size. However, the film thickness had no remarkable effect.

  12. High-throughput characterization of film thickness in thin film materials libraries by digital holographic microscopy.

    Science.gov (United States)

    Lai, Yiu Wai; Krause, Michael; Savan, Alan; Thienhaus, Sigurd; Koukourakis, Nektarios; Hofmann, Martin R; Ludwig, Alfred

    2011-10-01

    A high-throughput characterization technique based on digital holography for mapping film thickness in thin-film materials libraries was developed. Digital holographic microscopy is used for fully automatic measurements of the thickness of patterned films with nanometer resolution. The method has several significant advantages over conventional stylus profilometry: it is contactless and fast, substrate bending is compensated, and the experimental setup is simple. Patterned films prepared by different combinatorial thin-film approaches were characterized to investigate and demonstrate this method. The results show that this technique is valuable for the quick, reliable and high-throughput determination of the film thickness distribution in combinatorial materials research. Importantly, it can also be applied to thin films that have been structured by shadow masking.

  13. Fabrication of BIT thick films patterned by proton beam writing

    Science.gov (United States)

    Yamaguchi, Masaki; Watanabe, Kazuki; Nishikawa, Hiroyuki; Masuda, Yoichiro

    2017-07-01

    In this study, we fabricated thick films with polyvinylpyrrolidone (PVP) added to bismuth titanate (Bi4Ti3O12) to form a lead-free ferroelectric material. We examined the direct patterning of these materials by using proton-beam irradiation. When 50% PVP was added to the organic source solution, the c-axis orientation was promoted and cracks were suppressed due to stress relaxation. In addition, a dot and an arbitrary-shape micro-pattern were formed on bismuth-titanate thick film by micromachining using a proton beam.

  14. Electroplated thick-film cobalt platinum permanent magnets

    Science.gov (United States)

    Oniku, Ololade D.; Qi, Bin; Arnold, David P.

    2016-10-01

    The material and magnetic properties of multi-micron-thick (up to 6 μm) L10 CoPt magnetic films electroplated onto silicon substrates are investigated as candidate materials for integration in silicon-based microsystems. The influence of various process conditions on the structure and magnetic properties of electroplated CoPt thick-films is studied in order to better understand the complex process/structure/property relationships associated with the electroplated films. Process variables studied here include different seed layers, electroplating current densities (ranging from 25-200 mA/cm2), deposition times (up to 60 min), and post-deposition annealing times and temperatures. Analyses include film morphology, film thickness, composition, surface roughness, grain size, phase volume fractions, and L10 ordering parameter. Key correlations are found relating process and structure variations to the extrinsic magnetic properties (remanence, coercivity, squareness, and energy product). Strong hard magnetic properties (Br ~0.8 T, Hci ~800 kA/m, squareness close to 0.9, and BHmax of 100 kJ/m3) are obtained for films deposited on Si/TiN/Ti/Cu at current densities of 100 mA/cm2, pH of 7, and subsequently annealed at 675 °C for 30 min.

  15. The thickness dependence of dielectric permittivity in thin films

    Science.gov (United States)

    Starkov, Ivan A.; Starkov, Alexander S.

    2016-08-01

    It is well known that the physical properties of thin films depend on their thickness. For a description of such dependences, it is proposed to use a classical model taking into account the presence of film interfaces. A dielectric ball near the half-space was chosen to adopt the approach. The dependence of the effective permittivity of the ball on geometrical and physical parameters of the system is analyzed. It is demonstrated that the dielectric constant of a film can be presented as a sum of the constant of a bulk material and the interface term.

  16. Quantum Griffiths singularity of superconductor-metal transition in Ga thin films.

    Science.gov (United States)

    Xing, Ying; Zhang, Hui-Min; Fu, Hai-Long; Liu, Haiwen; Sun, Yi; Peng, Jun-Ping; Wang, Fa; Lin, Xi; Ma, Xu-Cun; Xue, Qi-Kun; Wang, Jian; Xie, X C

    2015-10-30

    The Griffiths singularity in a phase transition, caused by disorder effects, was predicted more than 40 years ago. Its signature, the divergence of the dynamical critical exponent, is challenging to observe experimentally. We report the experimental observation of the quantum Griffiths singularity in a two-dimensional superconducting system. We measured the transport properties of atomically thin gallium films and found that the films undergo superconductor-metal transitions with increasing magnetic field. Approaching the zero-temperature quantum critical point, we observed divergence of the dynamical critical exponent, which is consistent with the Griffiths singularity behavior. We interpret the observed superconductor-metal quantum phase transition as the infinite-randomness critical point, where the properties of the system are controlled by rare large superconducting regions.

  17. Screen printed thick film based pMUT arrays

    DEFF Research Database (Denmark)

    Hedegaard, Tobias; Pedersen, T; Thomsen, Erik Vilain;

    2008-01-01

    This article reports on the fabrication and characterization of lambda-pitched piezoelectric micromachined ultrasound transducer (pMUT) arrays fabricated using a unique process combining conventional silicon technology and low cost screen printing of thick film PZT. The pMUTs are designed as 8...

  18. MEMS Accelerometer with Screen Printed Piezoelectric Thick Film

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Lau-Moeller, R.; Bove, T.

    2006-01-01

    A bulk-micromachined piezoelectric MEMS accelerometer with screen printed piezoelectric Pb(ZrxTil )O3(PZT) thick film (TF) as the sensing material has been fabricated and characterized. The accelerometer has a four beam structure with a central seismic mass (3600x3600x500 pm3) and a total chip size...

  19. Shearing Nanometer-Thick Confined Hydrocarbon Films: Friction and Adhesion

    DEFF Research Database (Denmark)

    Sivebæk, I. M.; Persson, B. N. J.

    2016-01-01

    We present molecular dynamics (MD) friction and adhesion calculations for nanometer-thick confined hydrocarbon films with molecular lengths 20, 100 and 1400 carbon atoms. We study the dependency of the frictional shear stress on the confining pressure and sliding speed. We present results...

  20. Presentation and characterization of novel thick-film PZT microactuators

    Energy Technology Data Exchange (ETDEWEB)

    Chalvet, Vincent; Habineza, Didace, E-mail: didace.habineza@femto-st.fr; Rakotondrabe, Micky; Clévy, Cédric

    2016-04-01

    We propose in this paper the characterization of a new generation of piezoelectric cantilevers called thick-films piezoelectric actuators. Based on the bonding and thinning process of a bulk PZT layer onto a silicon layer, these cantilevers can provide better static and dynamic performances compared to traditional piezocantilevers, additionally to the small dimensions.

  1. Screen-printed piezoceramic thick films for miniaturised devices

    DEFF Research Database (Denmark)

    Lou-Moeller, R.; Hindrichsen, Christian Carstensen; Thamdrup, Lasse Højlund;

    2007-01-01

    The development towards smaller devices with more functions integrated calls for new and improved manufacturing processes. The screen-printing process is quite well suited for miniaturised and integrated devices, since thick films can be produced in this manner without the need for further machin...

  2. Triaxial MEMS accelerometer with screen printed PZT thick film

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Almind, Ninia Sejersen; Brodersen, Simon Hedegaard

    2010-01-01

    . In this work integration of a screen printed piezoelectric PZT thick film with silicon MEMS technology is shown. A high bandwidth triaxial accelerometer has been designed, fabricated and characterized. The voltage sensitivity is 0.31 mV/g in the vertical direction, 0.062 mV/g in the horizontal direction...

  3. Polymer thick-film sensors: possibilities for smartcard biometrics

    NARCIS (Netherlands)

    Henderson, N.J.; Papakostas, T.V.; White, N.M.; Hartel, P.H.

    2002-01-01

    In this paper the potential of polymer thick-film sensors are assessed for use as biometric sensors on smartcards. Piezoelectric and piezoresistive sensors have been printed on flexible polyester, then bonded to smartcard blanks. The tactile interaction of a person with these sensors has been invest

  4. Relaxation in Thin Polymer Films Mapped across the Film Thickness by Astigmatic Single-Molecule Imaging

    KAUST Repository

    Oba, Tatsuya

    2012-06-19

    We have studied relaxation processes in thin supported films of poly(methyl acrylate) at the temperature corresponding to 13 K above the glass transition by monitoring the reorientation of single perylenediimide molecules doped into the films. The axial position of the dye molecules across the thickness of the film was determined with a resolution of 12 nm by analyzing astigmatic fluorescence images. The average relaxation times of the rotating molecules do not depend on the overall thickness of the film between 20 and 110 nm. The relaxation times also do not show any dependence on the axial position within the films for the film thickness between 70 and 110 nm. In addition to the rotating molecules we observed a fraction of spatially diffusing molecules and completely immobile molecules. These molecules indicate the presence of thin (<5 nm) high-mobility surface layer and low-mobility layer at the interface with the substrate. (Figure presented) © 2012 American Chemical Society.

  5. Effect of Film Thickness on Properties of a-Si∶H Films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The a-Si∶H films with different thickness smaller than 1μm were deposited by plasma enhanced chemical vapor deposition (PECVD) under the optimum deposition conditions. The effect of different thickness on film properties is analyzed.The results show that,with the increase of the film thickness,the dark conductivity, photoconductivity and threshold voltage increase, the optical gap and peak ratio of TA to TO in the Raman spectra decrease, the refractive index keeps almost constant, and the optical absorption coefficient and current ratio of on/off state first maximize and then reduce.

  6. Film-thickness dependence of structure formation in ultra-thin polymer blend films

    CERN Document Server

    Gutmann, J S; Stamm, M

    2002-01-01

    We investigated the film-thickness dependence of structure formation in ultra-thin polymer blend films prepared from solution. As a model system we used binary blends of statistical poly(styrene-co-p-bromostyrene) copolymers of different degrees of bromination. Ultra-thin-film samples differing in miscibility and film thickness were prepared via spin coating of common toluene solutions onto silicon (100) substrates. The resulting morphologies were investigated with scanning force microscopy, reflectometry and grazing-incidence scattering techniques using both X-rays and neutrons in order to obtain a picture of the sample structure at and below the sample surface. (orig.)

  7. Influence of substrate and film thickness on polymer LIPSS formation

    Science.gov (United States)

    Cui, Jing; Nogales, Aurora; Ezquerra, Tiberio A.; Rebollar, Esther

    2017-02-01

    Here we focus on the influence of both, substrate and film thickness on polymer Laser Induced Periodic Surface Structures (LIPSS) formation in polymer films. For this aim a morphological description of ripples structures generated on spin-coated polystyrene (PS) films by a linearly polarized laser beam with a wavelength of 266 nm is presented. The influence of different parameters on the quality and characteristics of the formed laser-induced periodic surface structures (LIPSS) was investigated. We found that well-ordered LIPSS are formed either on PS films thinner than 200 nm or thicker than 400 nm supported on silicon substrates as well as on thicker free standing films. However less-ordered ripples are formed on silicon supported films with intermediate thicknesses in the range of 200-380 nm. The effect of the thermal and optical properties of the substrate on the quality of LIPSS was analyzed. Differences observed in the fluence and number of pulses needed for the onset of surface morphological modifications is explained considering two main effects which are: (1) The temperature increase on polymer surface induced by the action of cumulative laser irradiation and (2) The differences in thermal conductivity between the polymer and the substrate which strongly affect the heat dissipation generated by irradiation.

  8. Thermal treatment of superconductor thin film of the BSCCO system using domestic microwave oven

    Science.gov (United States)

    Silveira, J. B.; Carvalho, C. L.; Torsoni, G. B.; Aquino, H. A.; Zadorosny, R.

    2012-08-01

    In this work, we report the preparation of a superconductor thin film of the BSCCO system using a good quality powder with nominal composition Bi1.8Pb0.4Sr2CaCu2Ox which was thermally treated using a domestic microwave oven (2.45 GHz, 800 W). This film was grew on a single crystal of LaAlO3 (1 0 0) substrate and exhibited a crystalline structure with the c-axis perpendicular to the plane of the substrate. An onset superconducting transition temperature was measured at 80 K.

  9. Thermal treatment of superconductor thin film of the BSCCO system using domestic microwave oven

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, J.B.; Carvalho, C.L.; Torsoni, G.B.; Aquino, H.A. [Grupo de Desenvolvimento e Aplicacoes de Materiais, Departamento de Fisica e Quimica, Faculdade de Engenharia de Ilha Solteira, Univers Estadual Paulista-UNESP, Caixa Postal 31, 15385-000 Ilha Solteira, SP (Brazil); Zadorosny, R., E-mail: rafazad@yahoo.com.br [Grupo de Desenvolvimento e Aplicacoes de Materiais, Departamento de Fisica e Quimica, Faculdade de Engenharia de Ilha Solteira, Univers Estadual Paulista-UNESP, Caixa Postal 31, 15385-000 Ilha Solteira, SP (Brazil)

    2012-08-15

    In this work, we report the preparation of a superconductor thin film of the BSCCO system using a good quality powder with nominal composition Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2}CaCu{sub 2}O{sub x} which was thermally treated using a domestic microwave oven (2.45 GHz, 800 W). This film was grew on a single crystal of LaAlO{sub 3} (1 0 0) substrate and exhibited a crystalline structure with the c-axis perpendicular to the plane of the substrate. An onset superconducting transition temperature was measured at 80 K.

  10. Superconductor films with improved flux pinning and reduced AC losses

    Science.gov (United States)

    Goyal, Amit

    2011-04-05

    The present invention relates to a method for producing a defect-containing superconducting film, the method comprising (a) depositing a phase-separable layer epitaxially onto a biaxially-textured substrate, wherein the phase-separable layer includes at least two phase-separable components; (b) achieving nanoscale phase separation of the phase-separable layer such that a phase-separated layer including at least two phase-separated components is produced; and (c) depositing a superconducting film epitaxially onto said phase-separated components of the phase-separated layer such that nanoscale features of the phase-separated layer are propagated into the superconducting film.

  11. Enhanced superconductivity and superconductor to insulator transition in nano-crystalline molybdenum thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Shilpam; Amaladass, E.P. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Sharma, Neha [Surface & Nanoscience Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Harimohan, V. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Amirthapandian, S. [Materials Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Mani, Awadhesh, E-mail: mani@igcar.gov.in [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

    2017-06-01

    Disorder driven superconductor to insulator transition via intermediate metallic regime is reported in nano-crystalline thin films of molybdenum. The nano-structured thin films have been deposited at room temperature using DC magnetron sputtering at different argon pressures. The grain size has been tuned using deposition pressure as the sole control parameter. A variation of particle sizes, room temperature resistivity and superconducting transition has been studied as a function of deposition pressure. The nano-crystalline molybdenum thin films are found to have large carrier concentration but very low mobility and electronic mean free path. Hall and conductivity measurements have been used to understand the effect of disorder on the carrier density and mobilities. Ioffe-Regel parameter is shown to correlate with the continuous metal-insulator transition in our samples. - Highlights: • Thin films of molybdenum using DC sputtering have been deposited on glass. • Argon background pressure during sputtering was used to tune the crystallite sizes of films. • Correlation in deposition pressure, disorder and particle sizes has been observed. • Disorder tuned superconductor to insulator transition along with an intermediate metallic phase has been observed. • Enhancement of superconducting transition temperature and a dome shaped T{sub C} vs. deposition pressure phase diagram has been observed.

  12. Anisotropic resistivity in plasma-sprayed silicon thick films

    Science.gov (United States)

    Kharas, Boris Dave; Sampath, Sanjay; Gambino, Richard J.

    2005-05-01

    Silicon thick films deposited by thermal plasma spray are of interest as inexpensive electronic materials for conformal meso-scale electronics applications. In addition they also serve as a model system for the investigation of electrical properties of coatings with layered anisotropy. In this study impedance spectroscopy was used to measure the complex resistivity of free-standing 64μm-thick polycrystalline silicon films deposited by thermal plasma spraying in an atmospheric ambient. Impedance spectroscopy measurements were taken in the through-thickness (across-splat) and edge-to-edge (in-splat) directions and revealed a resistivity difference of approximately 7.5±0.23 between the two directions. The complex resistivity results are explained on the basis of a brick-layer type model, associated with the layered splat microstructure obtained from cross-sectional transmission electron microscope imaging of the films. In addition a circuit-based model made up of parallel, resistor-capacitor elements in series, and Cole-Cole and Davidson-Cole impedance functions were used to fit the impedance data to extract material parameters and contributions from the grains and splat boundaries. Furthermore, thermal processing and phosphorus doping is shown to lead to higher and lower resistivity, respectively, in the films.

  13. Growth of cuprate high temperature superconductor thin films

    Directory of Open Access Journals (Sweden)

    H-U Habermeier

    2006-09-01

    Full Text Available   This paper reviews briefly the development of physical vapour deposition based HTS thin film preparation technologies to today’s state-of-the-art methods. It covers the main trends of in-situ process and growth control. The current activities to fabricate tapes for power applications as well as to tailor interfaces in cuprate are described. Some future trends in HTS thin film research, both for science as well as application driven activities are outlined.

  14. Scanned probe microscopy for thin film superconductor development

    Energy Technology Data Exchange (ETDEWEB)

    Moreland, J. [National Institute of Standards and Technology, Boulder, CO (United States)

    1996-12-31

    Scanned probe microscopy is a general term encompassing the science of imaging based on piezoelectric driven probes for measuring local changes in nanoscale properties of materials and devices. Techniques like scanning tunneling microscopy, atomic force microscopy, and scanning potentiometry are becoming common tools in the production and development labs in the semiconductor industry. The author presents several examples of applications specific to the development of high temperature superconducting thin films and thin-film devices.

  15. Effects of thickness on electronic structure of titanium thin films

    Indian Academy of Sciences (India)

    Güvenç Akgül

    2014-02-01

    Effects of thickness on the electronic structure of e-beam evaporated thin titanium films were studied using near-edge X-ray absorption fine structure (NEXAFS) technique at titanium 2,3 edge in total electron yield (TEY) mode and transmission yield mode. Thickness dependence of 2,3 branching ratio (BR) of titanium was investigated and it was found that BR below 3.5 nm shows a strong dependence on film thickness. Mean electron escape depth () in titanium, an important parameter for surface applications, was determined to be = 2.6 ± 0.1 nm using 2,3 resonance intensity variation as a function of film thickness. The average 3/2 white line intensity ratio of titanium was obtained as 0.89 from the ratio of amplitudes of each 3 and 2 peaks and 0.66 from the integrated area under each 3 and 2 peaks. In addition, a theoretical calculation for pure titanium was presented for comparison with experimental data.

  16. Epitaxial layers of 2122 BCSCO superconductor thin films having single crystalline structure

    Science.gov (United States)

    Pandey, Raghvendra K. (Inventor); Raina, Kanwal K. (Inventor); Solayappan, Narayanan (Inventor)

    1995-01-01

    A substantially single phase, single crystalline, highly epitaxial film of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8 superconductor which has a T.sub.c (zero resistance) of 83K is provided on a lattice-matched substrate with no intergrowth. This film is produced by a Liquid Phase Epitaxy method which includes the steps of forming a dilute supercooled molten solution of a single phase superconducting mixture of oxides of Bi, Ca, Sr, and Cu having an atomic ratio of about 2:1:2:2 in a nonreactive flux such as KCl, introducing the substrate, e.g., NdGaO.sub.3, into the molten solution at 850.degree. C., cooling the solution from 850.degree. C. to 830.degree. C. to grow the film and rapidly cooling the substrate to room temperature to maintain the desired single phase, single crystalline film structure.

  17. Effect of film thickness on microstructure parameters and optical constants of CdTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Shaaban, E.R., E-mail: esam_ramadan2008@yahoo.co [Physics Department, Faculty of Science, Qassim University, Buridah 51452 (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut, P.O. 71452 (Egypt); Afify, N. [Physics Department, Assiut University, Assiut (Egypt); El-Taher, A. [Physics Department, Faculty of Science, Qassim University, Buridah 51452 (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut, P.O. 71452 (Egypt)

    2009-08-12

    Different thickness of cadmium telluride (CdTe) thin films was deposited onto glass substrates by the thermal evaporation technique. Their structural characteristics were studied by X-ray diffraction (XRD). The XRD experiments showed that the films are polycrystalline and have a zinc-blende (cubic) structure. The microstructure parameters, crystallite size and microstrain were calculated. It is observed that the crystallite size increases and microstrain decreases with the increase in the film thickness. The fundamental optical parameters like band gap and extinction coefficient are calculated in the strong absorption region of transmittance and reflectance spectrum. The possible optical transition in these films is found to be allowed direct transition with energy gap increase from 1.481 to 1.533 eV with the increase in the film thickness. It was found that the optical band gap increases with the increase in thickness. The refractive indices have been evaluated in transparent region in terms of envelope method, which has been suggested by Swanepoul in the transparent region. The refractive index can be extrapolated by Cauchy dispersion relationship over the whole spectral range, which extended from 400 to 2500 nm. It is observed that the refractive index, n increases on increasing the film thickness up to 671 nm and then the variation of n with higher thickness lie within the experimental errors.

  18. Chemical vapor deposition reactor. [providing uniform film thickness

    Science.gov (United States)

    Chern, S. S.; Maserjian, J. (Inventor)

    1977-01-01

    An improved chemical vapor deposition reactor is characterized by a vapor deposition chamber configured to substantially eliminate non-uniformities in films deposited on substrates by control of gas flow and removing gas phase reaction materials from the chamber. Uniformity in the thickness of films is produced by having reactive gases injected through multiple jets which are placed at uniformally distributed locations. Gas phase reaction materials are removed through an exhaust chimney which is positioned above the centrally located, heated pad or platform on which substrates are placed. A baffle is situated above the heated platform below the mouth of the chimney to prevent downdraft dispersion and scattering of gas phase reactant materials.

  19. Thickness dependence of the levitation performance of double-layer high-temperature superconductor bulks above a magnetic rail

    Energy Technology Data Exchange (ETDEWEB)

    Sun, R.X.; Zheng, J.; Liao, X.L.; Che, T.; Gou, Y.F.; He, D.B.; Deng, Z.G., E-mail: zgdeng@gmail.com

    2014-10-15

    Highlights: • Thickness optimization of double-layer bulk HTSC arrangement is studied. • The new bulk HTSC arrangement makes better use of the flux distribution of the magnetic rails. • Levitation performance can be enhanced with the optimization. • The optimization can meet large levitation force requirements for HTS Maglev system. - Abstract: A double-layer high-temperature superconductor (HTSC) arrangement was proposed and proved to be able to bring improvements to both levitation force and guidance force compared with present single-layer HTSC arrangement. To fully exploit the applied magnetic field by a magnetic rail, the thickness dependence of a double-layer HTSC arrangement on the levitation performance was further investigated in the paper. In this study, the lower-layer bulk was polished step by step to different thicknesses, and the upper-layer bulk with constant thickness was directly superimposed on the lower-layer one. The levitation force and the force relaxation of the double-layer HTSC arrangement were measured above a Halbach magnetic rail. Experimental result shows that a bigger levitation force and a less levitation force decay could be achieved by optimizing the thickness of the lower-layer bulk HTSC. This thickness optimization method could be applied together with former reported double-layer HTSC arrangement method with aligned growth sector boundaries pattern. This series of study on the optimized combination method do bring a significant improvement on the levitation performance of present HTS maglev systems.

  20. Processing and characterization of high temperature superconductor thin films deposited by electron beam co-evaporation

    Science.gov (United States)

    Huh, Jeong-Uk

    Ever since the high temperature superconductors (HTS) were discovered in the late 1980s, there have been enormous efforts to make this into applications such as power transmission cables, transformers, motors and generators. However, many obstacles in performance and high manufacturing cost made this difficult. The first generation HTS wires had low critical current density and were expensive to fabricate. The motivation of this research was to make high performance and low cost second generation HTS coated conductor. Electron beam co-evaporation technique was used to deposit YBCO(YBa2Cu3O7-x ) film at a high rate (10nm/s and higher) on single crystals and metal tapes. The oxygen pressure at the stage of depositing Y, Ba, Cu was 5x10 -5 Torr and the process temperature was 810-840°C. In-situ Fourier Transform Infrared spectroscopy (FTIR) was used to monitor the optical properties of the YBCO during and after deposition. The deposit transformed to a glassy amorphous mixture of Y, Ba and Cu at 3 mTorr of oxygen. YBCO crystallization occurred after extra oxygen was applied to several Torr. FTIR showed almost the same signature during the formation of YBCO and liquid Ba-Cu-O during deposition, which indicates the liquid played an important role in determining the properties of YBCO in terms of providing epitaxy and fast transport of atoms to nucleate on the film-metal interface. The transformation was very rapid---seconds to minutes, compared to minutes to hours for other post-reaction processes. The oxygen partial pressure and the rate of oxidation (supersaturation) in the liquid region defined in the YBCO phase stability diagram determined the electrical and microstructural properties. In-situ X-ray diffraction heating stage with ambient control was utilized to study this supersaturation effect and explore the temperature-pressure space during YBCO growth. With all the information gathered from FTIR and XRD in-situ experiments and also with nano-engineering during

  1. Discrete component bonding and thick film materials study

    Science.gov (United States)

    Kinser, D. L.

    1975-01-01

    The results are summarized of an investigation of discrete component bonding reliability and a fundamental study of new thick film resistor materials. The component bonding study examined several types of solder bonded components with some processing variable studies to determine their influence upon bonding reliability. The bonding reliability was assessed using the thermal cycle: 15 minutes at room temperature, 15 minutes at +125 C 15 minutes at room temperature, and 15 minutes at -55 C. The thick film resistor materials examined were of the transition metal oxide-phosphate glass family with several elemental metal additions of the same transition metal. These studies were conducted by preparing a paste of the subject composition, printing, drying, and firing using both air and reducing atmospheres. The resulting resistors were examined for adherence, resistance, thermal coefficient of resistance, and voltage coefficient of resistance.

  2. A sensitive magnetic field sensor using BPSCCO thick film

    Indian Academy of Sciences (India)

    S Vijay Srinivas; Abhijit Ray; T K Dey

    2001-08-01

    A highly sensitive magnetic sensor operating at liquid nitrogen temperature and based on BPSCCO screen-printed thick film, is reported. The sensor resistance for an applied magnetic field of 100 × 10–4T(100 gauss) exhibits an increase by 360% of its value in zero field at 77.4 K. The performance of the sensor in presence of magnetic field, the hysteretic features and the effect of thermal cycling, has been discussed.

  3. High-performance PMN-PT thick films.

    Science.gov (United States)

    Kosec, Marija; Ursic, Hana; Holc, Janez; Hrovat, Marko; Kuscer, Danjela; Malic, Barbara

    2010-10-01

    This article describes some of our work on ₀.₆₅Pb(Mg₁/₃Nb(₂/₃)O₃-₀.₃₅PbTiO₃ (0.65PMN-0.35PT) thick films printed on alumina substrates. These thick films, with the nominal composition ₀.₆₅Pb(Mg₁/₃Nb(₂/₃)O₃-₀.₃₅PbTiO₃, were produced by screen-printing and firing a paste prepared from an organic vehicle and pre-reacted fine particles of avery chemically homogeneous powder. To improve the adhesion of the 0.65PMN-0.35PT to the platinized alumina substrate,a Pb(Zr₀.₅₃Ti₀.₄₇)O₃ layer was deposited between the electrode and the substrate. The samples were then sintered at 950 °C for 2 h with various amounts of packing powder on the alumina (Al₂O₃) substrates. The sintering procedure was optimized to obtain dense 0.65PMN-0.35PT films. The films were then characterized using scanning electron microscopy as well as measurements of the dielectric and piezoelectric constants.The electrostrictive behavior of the 0.65PMN-0.35PT thick films was investigated using an atomic force microscope(AFM). Finally, substrate-free, large-displacement bending type actuators were prepared and characterized, and the normalized displacement (i.e., the displacement per unit length) of the actuators was determined to be 55 μm/cm at 3.6 kV/cm.

  4. The Effect of Thickness of Aluminium Films on Optical Reflectance

    Directory of Open Access Journals (Sweden)

    Robert Lugolole

    2015-01-01

    Full Text Available In Uganda and Africa at large, up to 90% of the total energy used for food preparation and water pasteurization is from fossil fuels particularly firewood and kerosene which pollute the environment, yet there is abundant solar energy throughout the year, which could also be used. Uganda is abundantly rich in clay minerals such as ball clay, kaolin, feldspar, and quartz from which ceramic substrates were developed. Aluminium films of different thicknesses were deposited on different substrates in the diffusion pump microprocessor vacuum coater (Edwards AUTO 306. The optical reflectance of the aluminium films was obtained using a spectrophotometer (SolidSpec-3700/DUV-UV-VIS-NIR at various wave lengths. The analysis of the results of the study revealed that the optical reflectance of the aluminium films was above 50% and increased with increasing film thickness and wavelength. Thus, this method can be used to produce reflector systems in the technology of solar cooking and other appliances which use solar energy.

  5. Tape casting and partial melting of Bi-2212 thick films

    Energy Technology Data Exchange (ETDEWEB)

    Buhl, D.; Lang, T.; Heeb, B. [Nichtmetallische Werkstoffe, Zuerich (Switzerland)] [and others

    1994-12-31

    To produce Bi-2212 thick films with high critical current densities tape casting and partial melting is a promising fabrication method. Bi-2212 powder and organic additives were mixed into a slurry and tape casted onto glass by the doctor blade tape casting process. The films were cut from the green tape and partially molten on Ag foils during heat treatment. We obtained almost single-phase and well-textured films over the whole thickness of 20 {mu}m. The orientation of the (a,b)-plane of the grains were parallel to the substrate with a misalignment of less than 6{degrees}. At 77K/OT a critical current density of 15`000 A/cm{sup 2} was reached in films of the dimension 1cm x 2cm x 20{mu}m (1{mu}V/cm criterion, resistively measured). At 4K/OT the highest value was 350`000 A/cm{sup 2} (1nV/cm criterion, magnetically measured).

  6. Thickness-Dependent Surfactant Behavior in Trilayer Polymer Films

    Science.gov (United States)

    Sun, Yan; Shull, Kenneth; Wang, Jin

    2010-03-01

    The ability for thin liquid films to wet and remain thermodynamically stable on top of one another is a fundamental challenge in developing high quality paints, coatings, adhesives, and other industrial products. Since intermolecular interactions and interfacial energies dominate in the film thickness regime from tens to hundreds of nanometers, it is desirable to tune these long-range and short-range forces in a simple, controllable manner. Starting from an unstable model homopolymer bilayer (poly(styrene)/poly(4-vinylpyridine)), we demonstrate that sandwiching an additional homopolymer layer (poly(4-bromostyrene)) between the two layers can provide needed surfactancy. As the thickness of this center layer is increased, the full trilayer transitions from unstable (thin) to stable (moderate) to unstable (thick). We experimentally show using x-ray standing waves generated via total external reflection (TER-XSW), atomic force microscopy (AFM), and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) that this behavior can be directly attributed to the autophobic dewetting phenomenon, in which the surfactant layer is thin enough to remain stable but thick enough to shield the neighboring layers, highlighting a general approach to stabilizing multilayer systems.

  7. Thickness dependence of the levitation performance of double-layer high-temperature superconductor bulks above a magnetic rail

    Science.gov (United States)

    Sun, R. X.; Zheng, J.; Liao, X. L.; Che, T.; Gou, Y. F.; He, D. B.; Deng, Z. G.

    2014-10-01

    A double-layer high-temperature superconductor (HTSC) arrangement was proposed and proved to be able to bring improvements to both levitation force and guidance force compared with present single-layer HTSC arrangement. To fully exploit the applied magnetic field by a magnetic rail, the thickness dependence of a double-layer HTSC arrangement on the levitation performance was further investigated in the paper. In this study, the lower-layer bulk was polished step by step to different thicknesses, and the upper-layer bulk with constant thickness was directly superimposed on the lower-layer one. The levitation force and the force relaxation of the double-layer HTSC arrangement were measured above a Halbach magnetic rail. Experimental result shows that a bigger levitation force and a less levitation force decay could be achieved by optimizing the thickness of the lower-layer bulk HTSC. This thickness optimization method could be applied together with former reported double-layer HTSC arrangement method with aligned growth sector boundaries pattern. This series of study on the optimized combination method do bring a significant improvement on the levitation performance of present HTS maglev systems.

  8. Superconductor to Quantum Metal Transitions in Ultra Thin Films

    Science.gov (United States)

    Lin, Yen-Hsiang; Goldman, Allen M.

    2009-03-01

    Homogeneous films of amorphous bismuth have been continuously tuned from the superconducting state by increasing a perpendicular magnetic field. Electrical transport and Hall measurements show that the non-superconducting states of the films are quantum-corrected metals. In the vicinity of transition field, the resistance can be fit by an Arrhenius type of conduction at high temperatures but this form fails at lower temperatures where the resistance is a non-monotonic function of temperature. This suggests that a two-phase regime develops near criticality. Theories suggest that this is in the form of superconducting puddles embedded in a normal matrix^1,2. ^1B. Spivak, P. Oreto, and S. A. Kivelson, Phys. Rev. B 77, 214523 (2008) ^2Y. Dubi, Y. Meir, and Y. Avishai, Nature 449, 876-880 (2007)

  9. An Investigation of the Relationship between Resistance and Thickness of Deposited Nickel Thin Film Resistors

    Directory of Open Access Journals (Sweden)

    Ericam R.R. Mucunguzi-Rugwebe

    2013-09-01

    Full Text Available The main purpose of this study is finding the relationship between resistance and thickness of deposited Nickel Thin Film Resistors. It was found that the Sheet Resistance, Rs, is inversely proportional to the thickness of the film on the substrate. It was also observed that when the film thickness is greater than 50 nm, films behave like ordinary resistors. In other words in bulk, films obey Ohm’s law if other physical quantities remain constant.

  10. Enhanced superconductivity and superconductor to insulator transition in nano-crystalline molybdenum thin films

    Science.gov (United States)

    Sharma, Shilpam; Amaladass, E. P.; Sharma, Neha; Harimohan, V.; Amirthapandian, S.; Mani, Awadhesh

    2017-06-01

    Disorder driven superconductor to insulator transition via intermediate metallic regime is reported in nano-crystalline thin films of molybdenum. The nano-structured thin films have been deposited at room temperature using DC magnetron sputtering at different argon pressures. The grain size has been tuned using deposition pressure as the sole control parameter. A variation of particle sizes, room temperature resistivity and superconducting transition has been studied as a function of deposition pressure. The nano-crystalline molybdenum thin films are found to have large carrier concentration but very low mobility and electronic mean free path. Hall and conductivity measurements have been used to understand the effect of disorder on the carrier density and mobilities. Ioffe-Regel parameter is shown to correlate with the continuous metal-insulator transition in our samples.

  11. Magnetic flux disorder and superconductor-insulator transition in nanohole thin films

    Science.gov (United States)

    Granato, Enzo

    2016-08-01

    We study the superconductor-insulator transition in nanohole ultrathin films in a transverse magnetic field by numerical simulation of a Josephson-junction array model. Geometrical disorder due to the random location of nanoholes in the film corresponds to random flux in the array model. Monte Carlo simulation in the path-integral representation is used to determine the critical behavior and the universal resistivity at the transition as a function of disorder and average number of flux quanta per cell, fo. The resistivity increases with disorder for noninteger fo while it decreases for integer fo, and reaches a common constant value in a vortex-glass regime above a critical value of the flux disorder Dfc. The estimate of Dfc and the resistivity increase for noninteger fo are consistent with recent experiments on ultrathin superconducting films with positional disordered nanoholes.

  12. Effect of film thickness on the columnar packing structures of discotic supramolecules in thin films.

    Science.gov (United States)

    Kim, Hyo-Sik; Choi, Sung-Min; Pate, Brian D; Park, Po Gyu

    2009-10-19

    The effects of film thickness on the columnar packing structure of discotic supramolecules in a thin supported film have been investigated by grazing-incidence small-angle X-ray scattering technique using magnetically aligned cobalt octa(n-decylthio)porphyrazine (CoS10) films on octadecyltrichlorosilane (OTS)-functionalized substrates as model systems. Magnetically aligned CoS10 films with a range of film thicknesses (49-845 nm) form uniaxially oriented 'edge-on' columnar superstructures with their columnar directors perpendicular to the applied magnetic field. However, the orientational ordering of the columnar packing in the plane perpendicular to the applied magnetic field is strongly dependent on the film thickness. While being damped by the elasticity of the side chains of CoS10, the strong interfacial interaction at the film-substrate interface propagates up to 50-100 nm from the substrate, maintaining the orientation of columnar packing in the plane perpendicular to the applied magnetic field. When the distance from the film-substrate interface becomes larger than about 100 nm, symmetric tilting of columnar layer orientation, which saturates at 11.5 degrees , occurs due to longitudinal edge dislocations induced by accumulated elastic deformation.

  13. Film thickness of mechanically worked lubricating grease at very low speeds

    NARCIS (Netherlands)

    Cen, H.; Lugt, Pieter Martin; Morales-Espejel, G.E.

    2014-01-01

    Several different types of commercially available greases, aged in a roll stability tester, have been tested in a ball-on-disc machine where the film thickness was measured using the interferometry method. The grease film thickness at very low speed is thicker than the base oil film thickness due to

  14. I. Low frequency noise in metal films at the superconducting transition. II. Resistance of superconductor - normal metal- superconductor sandwiches and the quasiparticle relaxation time

    Energy Technology Data Exchange (ETDEWEB)

    Hsiang, T.Y.

    1977-07-01

    Measurements of the noise power spectra of tin and lead films at the superconducting transition in the frequency range of 0.1 Hz to 5k Hz are reported. Two types of samples were made. Type A were evaporated directly onto glass substrate, while Type B were evaporated onto glass or sapphire substrate with a 50A aluminum underlay. The results were consistent with a thermal diffusion model which attributes the noise to the intrinsic temperature fluctuation in the metal film driven with a random energy flux source. In both types of metal films, the noise power was found to be proportional to (V-bar)/sup 2/ ..beta../sup 2//..cap omega.., where V-bar was the mean voltage across the sample, ..beta.. was the temperature coefficient of resistance and ..cap omega.. was the volume of the sample. Correlation of noises in two regions of the metal film a distance d apart was detected at frequencies less than or = D/..pi..d/sup 2/. A possible explanation of the noises using quantitative boundary conditions and implications of this work for device applications are discussed. Theoretical and experimental investigation are reported on the resistance of superconductor-normal metal-superconductor sandwiches near T/sub c/. The increase in SNS resistance is attributed to the penetration of normal electric current in the superconductor. It is proved from first principles that an electric field can exist inside the superconductor when quasiparticles are not equally populated on the two branches of the excitation spectrum, and such is the case in a current biased SNS junction. The electric field inside S decays according to a diffusion law. The diffusion length is determined by the quasiparticle ''branch-crossing'' relaxation time. The branch-crossing relaxation times were measured. Impurity-doping of tin was found to decrease this relaxation time.

  15. Vortices and quasiparticles near the superconductor-insulator transition in thin films.

    Science.gov (United States)

    Galitski, Victor M; Refael, G; Fisher, Matthew P A; Senthil, T

    2005-08-12

    We study the low temperature behavior of an amorphous superconducting film driven normal by a perpendicular magnetic-field (B). For this purpose we introduce a new two-fluid formulation consisting of fermionized field-induced vortices and electrically neutralized Bogoliubov quasiparticles (spinons) interacting via a long-ranged statistical interaction. This approach allows us to access a novel non-Fermi-liquid phase, which naturally interpolates between the low B superconductor and the high B normal metal. We discuss the properties of the resulting "vortex metal" phase.

  16. Influence of films thickness and structure on the photo-response of ZnO films

    Science.gov (United States)

    Ali Yıldırım, M.; Ateş, Aytunç

    2010-04-01

    ZnO thin films were grown using Successive Ionic Layer Adsorption and Reaction (SILAR) method on glass substrates at room temperature. Annealing temperatures and film thickness effect on the structural, morphological, optical and electrical properties of the films were studied. For this as-deposited films were annealed at 200, 300, 400 and 500 °C for 30 min in oxygen atmosphere. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies showed that the films are covered well with glass substrates and have good polycrystalline structure and crystalline levels. The film thickness effect on band gap values was investigated and band gap values were found to be within the range of 3.49-3.19 eV. The annealing temperature and light effect on electrical properties of the films were investigated and it was found that the current increased with increasing light intensity. The resistivity values were found as 10 5 Ω-cm for as-deposited films from electrical measurements. The resistivity decreased decuple with annealing temperature and decreased centuple with light emission for annealed films.

  17. Optimized Performances of Thick Film Organic Lighting-Emitting Diodes

    Institute of Scientific and Technical Information of China (English)

    WANG Xiu-Ru; ZHANG Zhi-Qiang; MA Dong-Ge; SUN Run-Guang

    2008-01-01

    @@ The performance of organic light-emitting diodes (OLEDs) with thick film is optimized.The alternative vana-dium oxide (V2O5) and N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPB) layers are used to enhance holes in the emissive region, and 4,7-dipheny-1,10-phenanthroline (Bphen) doped 8-tris-hydroxyquinoline alu-minium (Alq3) is used to enhance electrons is the emissive region, thus ITO/V2O5 (8nm)/NPB (52nm)/V2O5 (8nm)/NPB (52 nm)/Alq3 (30 and 45 nm)/Alq3:Bphen (30wt%, 30 and 45 nm)/LiF (1 nm)/Al (120nm) devices are fabricated.The thick-film devices show the turn-on voltage of about 3 V and the maximal power efficiency of 4.51m/W, which is 1.46 times higher than the conventional thin-film OLEDs.

  18. Thermoelectric properties of FeAs based superconductors, with thick perovskite- and Sm-O fluorite-type blocking layers

    Science.gov (United States)

    Singh, S. J.; Shimoyama, J.; Ogino, H.; Kishio, K.

    2015-11-01

    The transport properties (electrical resistivity, Hall and Seebeck coefficient, and thermal conductivity) of iron based superconductors with thick perovskite-type oxide blocking layers and fluorine-doped SmFeAsO were studied to explore their possible potential for thermoelectric applications. The thermal conductivity of former compounds depicts the dominated role of phonon and its value decreases rapidly below the Tc, suggesting the addition of scattering of phonons. Both the Seebeck coefficient (S) and Hall coefficient (RH) of all samples were negative in the whole temperature region below 300 K, indicating that the major contribution to the normal state conductivity is by electrons. In addition, the profile of S(T) and RH(T) of all samples have similar behaviours as would be expected for a multi-band superconductors. Although the estimated thermoelectric figure of merit (ZT) of these compounds was much lower than that of practically applicable thermoelectric materials, however its improvement can be expected by optimizing microstructure of the polycrystalline materials, such as densification and grain orientation.

  19. Thermoelectric properties of FeAs based superconductors, with thick perovskite- and Sm-O fluorite-type blocking layers

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.J., E-mail: s.j.singh@ifw-dresden.de [Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Leibniz Institute for Solid State and Materials Research (IFW), Helmhotzstrass 20, 01069 Dresden (Germany); Shimoyama, J.; Ogino, H.; Kishio, K. [Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2015-11-15

    Highlights: • Thermoelectric properties are studied for 22438 and 225411 with Sm1111. • Thermal and electrical coeff. follow almost the same behaviour for both categories. • The thermoelectric figure of merit has low value from the application point. • Major contribution to the normal state conductivity is by electron type carriers. - Abstract: The transport properties (electrical resistivity, Hall and Seebeck coefficient, and thermal conductivity) of iron based superconductors with thick perovskite-type oxide blocking layers and fluorine-doped SmFeAsO were studied to explore their possible potential for thermoelectric applications. The thermal conductivity of former compounds depicts the dominated role of phonon and its value decreases rapidly below the T{sub c}, suggesting the addition of scattering of phonons. Both the Seebeck coefficient (S) and Hall coefficient (R{sub H}) of all samples were negative in the whole temperature region below 300 K, indicating that the major contribution to the normal state conductivity is by electrons. In addition, the profile of S(T) and R{sub H}(T) of all samples have similar behaviours as would be expected for a multi-band superconductors. Although the estimated thermoelectric figure of merit (ZT) of these compounds was much lower than that of practically applicable thermoelectric materials, however its improvement can be expected by optimizing microstructure of the polycrystalline materials, such as densification and grain orientation.

  20. Deposition of ZnO Films on Freestanding CVD Thick Diamond Films

    Institute of Scientific and Technical Information of China (English)

    SUN Jian; BAI Yi-Zhen; YANG Tian-Peng; XU Yi-Bin; WANG Xin-Sheng; DU Guo-Tong; WU Han-Hua

    2006-01-01

    @@ For ZnO/diamond structured surface acoustic wave (SAW) filters, performance is sensitively dependent on the quality of the ZnO films. In this paper, we prepare highly-oriented and fine grained polycrystalline ZnO thin films with excellent surface smoothness on the smooth nucleation surfaces of freestanding CVD diamond films by metal organic chemical vapour deposition (MOCVD). The properties of the ZnO films are characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectrum. The influences of the deposition conditions on the quality of ZnO films are discussed briefly. ZnO/freestanding thick-diamond-film layered SAW devices with high response frequencies are expected to be developed.

  1. Effect of film thickness on the phase behaviors of diblock copolymer thin film.

    Science.gov (United States)

    Jung, Jueun; Park, Hae-Woong; Lee, Sekyung; Lee, Hyojoon; Chang, Taihyun; Matsunaga, Kazuyuki; Jinnai, Hiroshi

    2010-06-22

    A phase diagram was constructed for a polystyrene-block-polyisoprene (PS-b-PI, M(W) = 32 700, f(PI) = 0.670) in thin films on Si wafer as a function of film thickness over the range of 150-2410 nm (7-107L(0) (L(0): domain spacing)). The PS-b-PI exhibits a variety of ordered phases from hexagonally perforated lamellar (HPL) via double gyroid (DG) to hexagonally packed cylinder (HEX) before going to the disordered (DIS) phase upon heating. The morphology of the PS-b-PI in thin film was investigated by grazing incidence small-angle X-ray scattering, transmission electron microscopy, and transmission electron microtomography. In thin film, the phase transition temperature is difficult to be determined unequivocally with in situ heating processes since the phase transition is slow and two phases coexist over a wide temperature range. Therefore, in an effort to find an "equilibrium" phase, we determined the long-term stable phase formed after cooling the film from the DIS phase to a target temperature and annealing for 24 h at the temperature. The temperature windows of stable ordered phases are strongly influenced by the film thickness. As the film thickness decreases, the temperature window of layer-like structures such as HPL and HEX becomes wider, whereas that of the DG stable region decreases. For the films thinner than 160 nm (8L(0)), only the HPL phase was found. In the films exhibiting DG phase, a perforated layer structure at the free surface was found, which gradually converts to the internal DG structure. The relief of interfacial tension by preferential wetting appears to play an important role in controlling the morphology in very thin films.

  2. Thickness Dependence of Magnetic Properties in DyFeCo Films

    Institute of Scientific and Technical Information of China (English)

    Xiong Rui; Liu Hai-lin; Mei Xue-fei; Li Zuo-yi; Yang Xiao-fei; Shi Jing

    2004-01-01

    Films of amorphous DyFeCo were deposited on glass substrates using RF sputtering deposition system. The thickness dependence of the coercivity of DyFeCo films prepared under the same sputtering conditions was investigated. It is found that the composition is nearly thickness independent, while the coercivity is shown to increase with the film thickness increasing at the beginning, then above a certain thickness decrease with the thickness increasing. The thickness dependence of the coercivity is believed to be due to microstructure-induced variations in the short-range order during the film growth.

  3. Thickness effect on the microstructure, morphology and optoelectronic properties of ZnS films

    Science.gov (United States)

    Prathap, P.; Revathi, N.; Venkata Subbaiah, Y. P.; Ramakrishna Reddy, K. T.

    2008-01-01

    Thin films of ZnS with thicknesses ranging from 100 to 600 nm have been deposited on glass substrates by close spaced thermal evaporation. All the films were grown at the same deposition conditions except the deposition time. The effect of thickness on the physical properties of ZnS films has been studied. The experimental results indicated that the thickness affects the structure, lattice strain, surface morphology and optoelectronic properties of ZnS films significantly. The films deposited at a thickness of 100 nm showed hexagonal structure whereas films of thickness 300 nm or more showed cubic structure. However, coexistence of both cubic and hexagonal structures was observed in the films of 200 nm thickness. The surface roughness of the films showed an increasing trend at higher thicknesses of the films. A blue-shift in the energy band gap along with an intense UV emission band was observed with the decrease of film thickness, which are ascribed to the quantum confinement effect. The behaviour of optical constants such as refractive index and extinction coefficient were analysed. The variation of refractive index and extinction coefficient with thickness was explained on the basis of the contribution from the packing density of the layers. The electrical resistivity as well as the activation energy were evaluated and found to decrease with the increase of film thickness. The thickness had a significant influence on the optical band gap as well as the luminescence intensity.

  4. Optical properties and structures of silver thin films deposited by magnetron sputtering with different thicknesses

    Institute of Scientific and Technical Information of China (English)

    Xilian Sun; Ruijin Hong; Haihong Hou; Zhengxiu Fan; Jianda Shao

    2006-01-01

    A series of thin Ag films with different thicknesses grown under identical conditions are analyzed by means of spectrophotometer. From these measurements the values of refractive index and extinction coefficient are calculated. The films are deposited onto BK7 glass substrates by direct current (DC) magnetron sputtering. It is found that the optical properties of the Ag films can be affected by films thickness.Below critical thickness of 17 nm, which is the thickness at which Ag films form continuous films, the optical properties and constants vary significantly with thickness increasing and then tend to a stable value up to about 40 nm. At the same time, X-ray diffraction measurement is carried out to examine the microstructure evolution of Ag films as a function of films thickness. The relation between optical properties and microstructure is discussed.

  5. Thick film magnetic nanoparticulate composites and method of manufacture thereof

    Science.gov (United States)

    Ma, Xinqing (Inventor); Zhang, Yide (Inventor); Ge, Shihui (Inventor); Zhang, Zongtao (Inventor); Yan, Dajing (Inventor); Xiao, Danny T. (Inventor)

    2009-01-01

    Thick film magnetic/insulating nanocomposite materials, with significantly reduced core loss, and their manufacture are described. The insulator coated magnetic nanocomposite comprises one or more magnetic components, and an insulating component. The magnetic component comprises nanometer scale particles (about 1 to about 100 nanometers) coated by a thin-layered insulating phase. While the intergrain interaction between the immediate neighboring magnetic nanoparticles separated by the insulating phase provides the desired soft magnetic properties, the insulating material provides high resistivity, which reduces eddy current loss.

  6. Thick film fabrication of aluminum nitride microcircuits. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Perdieu, L.H.

    1994-03-01

    A new substrate material, aluminum nitride (AlN), and 11 new thick film inks were analyzed to determine their chemical compatibility, their electrical properties, their mechanical properties, and their overall suitability for use in the manufacturing of high-power microcircuits with efficient thermal properties. Because high-power chips emit a great deal of heat in a small surface area, a new substrate material was needed to dissipate that heat faster than the substrate material currently in use. Overall, the new materials were found to be acceptable for accomplishing this purpose.

  7. Laser sintering of thick-film conductors for microelectronic applications

    Science.gov (United States)

    Kinzel, Edward C.; Sigmarsson, Hjalti H.; Xu, Xianfan; Chappell, William J.

    2007-03-01

    This paper investigates fabrication of functional thick metal films using simultaneous laser sintering and patterning along with the fundamental physical phenomena that govern the laser sintering process. The effects of the processing parameters on the quality of the fabricated components are investigated through a heat transfer analysis. We show that our process has potentials for metallization of microelectronics directly onto substrates whose melting temperatures are much lower than the temperature needed for sintering, which is only possible by properly controlling the temperature field during laser sintering. Optimum properties of the fabricated components are obtained when certain thermal conditions are produced during laser heating.

  8. Levitation force and magnetization in bulk and thin film high T{sub c} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Riise, A.B

    1998-04-01

    The authors present high-resolution measurements of the repulsive vertical force and its associated stiffness between a Nd-B-Fe magnet and a YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconductor in cylindrical geometry. The results are compared with theoretical predictions. The calculations are based on a model in which the superconductor is assumed to be either a sintered granular material or consisting of grains embedded in a nonactive matrix so that only intragranular currents are important. The critical state model is applied to each grain individually and closed form expressions for both vertical force F{sub z} and stiffness are obtained in a configuration with cylindrical symmetry. The model explains all features of the experimental results in a consistent way. A good quantitative agreement has been obtained using only three adjustable parameters. Several central aspects of the phenomenon of magnetic levitation with high-T{sub c} superconductors are presented. High-resolution measurements are made of the repulsive vertical force and its associated stiffness as well as the horizontal stabilizing force and the stiffness governing lateral vibrations. The results obtained at 77 K using a granular YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} sample and Nd-Fe-B magnet in a rectangular levitation configuration are compared with theoretical predictions. The calculations, which are based on the critical state model with the assumption that it applies to the grins individually, give closed-form expressions for all the measured quantities. It is concluded that the present model explains all features of the observations in a consistent way. Using only three adjustable parameters a good agreement exists also at a quantitative level. Experimental studies and theoretical modelling of the levitation force on a permanent magnet placed above a superconducting thin film are offered. It is shown that measurements of the levitation force is a simple and precise method to determine the

  9. Effect of film thickness on magnetic properties of Cr/SmCo/Cr films

    Institute of Scientific and Technical Information of China (English)

    LI Ning; LI Baohe; FENG Chun; LI Minghua; YU Guanghua

    2012-01-01

    Cr/SmCo/Cr films with different SmCo thickness were deposited on glass substrates by magnetron sputtering,followed by an annealing process at 550℃for 20 min.Experimental results showed that the SmCo fihn of 30 nm exhibited two-phase behavior in the demagnetization process,the obvious kink was observed near zero.For the SmCo film of 50 nm,the kink was invisible,and a single phase like behavior was obtained in the demagnetization process.The reversal behavior became consistent in the thicker films.Moreover,the coercivity reduced and the saturated magnetization increased obviously with the increasing thickness.X-ray diffraction results indicated that the average grain size of SmCo5 in the thicker films were almost 30 nm,but the quantity of SmCo5 grains increased with the increasing thickness,which enhanced the intergrain exchange coupling (IEC) of the SmCo5 hard phases.The increase of lEC improved the magnetic properties of SmCo films with increasing thickness.

  10. Thickness optimization of Mo films for Cu(InGa)Se2 solar cell applications

    Institute of Scientific and Technical Information of China (English)

    Li Wei; Zhao Yan-Min; Liu Xing-Jiang; Ao Jian-Ping; Sun Yun

    2011-01-01

    Mo thin films are deposited on soda lime glass (SLG) substrates using DC magnetron sputtering. The Mo film thicknesses are varied from 0.08 μm to 1.5 μm to gain a better understanding of the growth process of the film. The residual stresses and the structural properties of these films are investigated, with attention paid particularly to the film thickness dependence of these properties. Residual stress decreases and yields a typical tensile-to-compressive stress transition with the increase of film thickness at the first stages of film growth. The stress tends to be stable with the further increase of film thickness. Using the Mo film with an optimum thickness of 1 μm as the back contact, the Cu(InGa)Se2 solar cell can reach a conversion efficiency of 13.15%.

  11. New Methods for Thin Film Deposition and First Investigations of the use of High Temperature Superconductors for Thin Film Cavities

    CERN Document Server

    Gustafsson, Anna; Vollenberg, Wilhelmus; Seviour, Rebecca

    2010-01-01

    Niobium thin film cavities have shown good and reliable performance for LEP and LHC, although there are limitations to overcome if this technique should be used for new accelerators such as the ILC. New coating techniques like High Power Impulse Magnetron Sputtering (HiPIMS) has shown very promising results and we will report on its possible improvements for Nb thin film cavity performance. Current materials used in accelerator Superconducting Radio Frequency (SRF) technologies operate at temperatures below 4 K, which require complex cryogenic systems. Researchers have investigated the use of High Temperature Superconductors (HTS) to form RF cavities, with limited success. We propose a new approach to achieve a high-temperature SRF cavity based on the superconducting ’proximity effect’. The superconducting proximity effect is the effect through which a superconducting material in close proximity to a non-superconducting material induces a superconducting condensate in the latter. Using this effect we hope...

  12. Nitrogen dioxide sensing properties of sprayed tungsten oxide thin film sensor: Effect of film thickness.

    Science.gov (United States)

    Ganbavle, V V; Mohite, S V; Agawane, G L; Kim, J H; Rajpure, K Y

    2015-08-01

    We report a study on effect of film thickness on NO2 sensing properties of sprayed WO3 thin films. WO3 thin films varying in thicknesses are deposited onto the glass substrates by simple spray pyrolysis technique by varying the volume of spray solution.Thin film gas sensors are characterized by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and photoluminescence (PL) techniques to study their physical properties. Film having thickness 745nm has shown highest gas response of 97% with 12 and 412s response and recovery times, respectively towards 100ppm NO2 concentration. Gas response of 20% is observed towards 10ppm NO2 at 200°C operating temperature. Sensitivity of the optimal sensor is 0.83%/ppm when operating at 200°C with 10ppm lower detection limit. The response of the sensor is reproducible and WO3 films are highly selective towards NO2 in presence of mist of various interfering gases viz. H2S, NH3, LPG, CO and SO2.

  13. Thick Films acoustic sensors devoted to MTR environment measurements. Thick Films acoustic sensors devoted to Material Testing Reactor environment measurements

    Energy Technology Data Exchange (ETDEWEB)

    Very, F.; Rosenkrantz, E.; Combette, P.; Ferrandis, J.Y. [University Montpellier, IES, UMR 5214, F-34000, Montpellier (France); CNRS, IES, UMR 5214, F-34000, Montpellier (France); Fourmentel, D.; Destouches, C.; Villard, J.F. [CEA, DEN, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St Paul lez Durance (France)

    2015-07-01

    The development of advanced instrumentation for in-pile experiments in Material Testing Reactor constitutes a main goal for the improvement of the nuclear fuel behavior knowledge. An acoustic method for fission gas release detection was tested with success during a first experiment called REMORA 3 in 2010 and 2011, and the results were used to differentiate helium and fission gas release kinetics under transient operating conditions. This experiment was lead at OSIRIS reactor (CEA Saclay, France). The maximal temperature on the sensor during the irradiation was about 150 deg. C. In this paper we present a thick film transducer produce by screen printing process. The screen printing of piezoelectric offers a wide range of possible applications for the development of acoustic sensors and piezoelectric structure for measurements in high temperature environment. We firstly produced a Lead Zirconate Titanate (PZT) based paste composed of Pz27 powder from Ferroperm, CF7575 glass, and organic solvent ESL 400. Likewise a Bismuth Titanate based paste synthesized in our laboratory was produced. With these inks we produced thick film up to 130 μm by screen printing process. Material properties characterizations of these thick-film resonators are essential for device design and applications. The piezoelectric coefficients d33 and pyro-electric P(T) coefficient are investigated. The highest P(T) and d33 are respectively 80 μC.m{sup -2}.K{sup -1} and 130 μC.N{sup -1} for the PZT transducer -which validates the fabrication process-. In view of the development of this transducer oriented for high temperature and irradiation environment, we investigated the electrical properties of the transducers for different ranges of frequencies and temperature - from 20 Hz up to 40 MHz between 30 and 400 deg. C. We highlight the evolution of the impedance response and piezoelectric parameters of screen printed piezoelectric structures on alumina. Shortly an irradiation will be realized in

  14. Environmentally compatible solder materials for thick film hybrid assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Vianco, P.T.; Rejent, J.A.; Hernandez, C.L. [Sandia National Labs., Albuquerque, NM (United States). Materials and Process Sciences Center

    1997-02-01

    New soldering materials and processes have been developed over the last several years to address a variety of environmental issues. One of the primary efforts by the electronics industry has involved the development of alternative solders to replace the traditional lead-containing alloys. Sandia National Laboratories is developing such alternative solder materials for printed circuit board and hybrid microcircuit (HMC) applications. This paper describes the work associated with low residue, lead-free soldering of thick film HMC`s. The response of the different materials to wetting, aging, and mechanical test conditions was investigated. Hybrid test vehicles were designed and fabricated with a variety of chip capacitors and leadless ceramic chip carriers to conduct thermal, electrical continuity, and mechanical evaluations of prototype joints. Microstructural development along the solder and thick film interface, after isothermal solid state aging over a range of elevated temperatures and times, was quantified using microanalytical techniques. Flux residues on soldered samples were stressed (temperature-humidity aged) to identify potential corrosion problems. Mechanical tests also supported the development of a solder joint lifetime prediction model. Progress of this effort is summarized.

  15. Ethanol vapour sensing properties of screen printed WO3 thick films

    Indian Academy of Sciences (India)

    R S Khadayate; R B Waghulde; M G Wankhede; J V Sali; P P Patil

    2007-04-01

    This paper presents ethanol vapour sensing properties of WO3 thick films. In this work, the WO3 thick films were prepared by standard screen-printing method. These films were characterized by X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM). The ethanol vapour sensing properties of these thick films were investigated at different operating temperatures and ethanol vapour concentrations. The WO3 thick films exhibit excellent ethanol vapour sensing properties with a maximum sensitivity of ∼1424.6% at 400°C in air atmosphere with fast response and recovery time.

  16. Influence of colorant and film thickness on thermal aging characteristics of oxo-biodegradable plastic bags

    Science.gov (United States)

    Leuterio, Giselle Lou D.; Pajarito, Bryan B.; Domingo, Carla Marie C.; Lim, Anna Patricia G.

    2016-05-01

    Functional, lightweight, strong and cheap plastic bags incorporated with pro-oxidants undergo accelerated degradation under exposure to heat and oxygen. This work investigated the effect of colorant and film thickness on thermal aging characteristics of commercial oxo-biodegradable plastic bag films at 70 °C. Degradation is monitored through changes in infrared absorption, weight, and tensile properties of thermally aged films. The presence of carbonyl band in infrared spectrum after 672 h of thermal aging supports the degradation behavior of exposed films. Results show that incorporation of colorant and increasing thickness exhibit low maximum weight uptake. Titanium dioxide as white colorant in films lowers the susceptibility of films to oxygen uptake but enhances physical degradation. Higher amount of pro-oxidant loading also contributes to faster degradation. Opaque films are characterized by low tensile strength and high elastic modulus. Decreasing the thickness contributes to lower tensile strength of films. Thermally aged films with colorant and low thickness promote enhanced degradation.

  17. Effect of preheating on the film thickness of contemporary composite restorative materials

    Directory of Open Access Journals (Sweden)

    Dimitrios Dionysopoulos

    2014-12-01

    Conclusion: The film thickness of the composites tested is material dependent. The thickness of the preheated conventional composites is significantly lower than those at room temperature. The conventional composites provide film thickness values greater than those of the flowable composites regardless of preheating temperature.

  18. Long-ranged interactions in thin TiN films at the superconductor-insulator transition?

    Energy Technology Data Exchange (ETDEWEB)

    Kronfeldner, Klaus; Strunk, Christoph [Institute for Experimental and Applied Physics, University of Regensburg (Germany); Baturina, Tatyana [A.V. Rzhanov Institute of Semiconductor Physics SB RAS, Novosibirsk (Russian Federation)

    2015-07-01

    We measured IV-characteristics and magnetoresistance of square TiN-films in the vicinity of the disorder-tuned superconductor-insulator transition (SIT) for different sizes (5 μm to 240 μm). While the films are superconducting at zero magnetic field, at finite fields a SIT occurs. The resistance shows thermally activated behaviour on both sides of the SIT. Deep in the superconducting regime the activation energy grows linear with the sample size as expected for a size-independent critical current density. Closer to the SIT the activation energy becomes clearly size independent. On the insulating side the magnetoresistance maximum and the activation energy both grow logarithmically with sample size which is consistent with a size-limited charge BKT (Berezinskii-Kosterlitz-Thouless) scenario. In order to test for the presence of long-ranged interactions in our films, we investigate the influence of a topgate. It is expected to screen the possible long-ranged interactions as the distance of the film to the gate is much shorter than the electrostatic screening length deduced from the size-dependent activation energy.

  19. Film thickness dependent ordering dynamics of lamellar forming diblock copolymer thin films.

    Science.gov (United States)

    Peters, Robert D; Dalnoki-Veress, Kari

    2012-12-01

    Ellipsometry is used in a novel way to study the ordering dynamics of symmetric poly(styrene-methyl methacrylate) diblock copolymer thin films. Ordered thin films form lamellae parallel to the substrate which can form islands or holes at the free surface to ensure commensurability of the layers. The sensitivity of ellipsometry provides the unique ability to probe morphological changes during the ordering process before the ultimate formation of islands or holes at the free surface. We observe three distinct stages in the ordering process: i) an ordering into an intermediate state, ii) an incubation time where the film structure remains constant and iii) the nucleation of islands or holes to achieve equilibrium lamellar morphology. The time-resolved measurement of an incubation period and initial ordering stage provides a means for studying the effect of thickness on the ordering kinetics. The dependence of incubation time on the commensurability of the initial film height is explained using strong segregation theory.

  20. Temperature- and thickness-dependent elastic moduli of polymer thin films.

    Science.gov (United States)

    Ao, Zhimin; Li, Sean

    2011-03-22

    The mechanical properties of polymer ultrathin films are usually different from those of their counterparts in bulk. Understanding the effect of thickness on the mechanical properties of these films is crucial for their applications. However, it is a great challenge to measure their elastic modulus experimentally with in situ heating. In this study, a thermodynamic model for temperature- (T) and thickness (h)-dependent elastic moduli of polymer thin films Ef(T,h) is developed with verification by the reported experimental data on polystyrene (PS) thin films. For the PS thin films on a passivated substrate, Ef(T,h) decreases with the decreasing film thickness, when h is less than 60 nm at ambient temperature. However, the onset thickness (h*), at which thickness Ef(T,h) deviates from the bulk value, can be modulated by T. h* becomes larger at higher T because of the depression of the quenching depth, which determines the thickness of the surface layer δ.

  1. Overlay mark optimization for thick-film resist overlay metrology

    Institute of Scientific and Technical Information of China (English)

    Zhu Liang; Li Jie; Zhou Congshu; Gu Yili; Yang Huayue

    2009-01-01

    For thick resist implant layers, such as a high voltage P well and a deep N well, systematic and uncorrectable overlay residues brought about by the tapered resist profiles were found. It was found that the tapered profile is closely related to the pattern density. Potential solutions of the manufacturing problem include hardening the film solidness or balancing the exposure density. In this paper, instead of focusing on the process change methodology,we intend to solve the issue of the overlay metrology error from the perspective of the overlay mark design. Based on the comparison of the overlay performances between the proposed overlay mark and the original design, it is shown that the optimized overlay mark target achieves better performance in terms of profiles, dynamic precision,tool induced shift (TIS), and residues. Furthermore, five types of overlay marks with dummy bars are studied, and a recommendation for the overlay marks is given.

  2. Preparation of Lead-free Thick-film Resistor Pastes

    Institute of Scientific and Technical Information of China (English)

    LUO Hui; LI Shihong; LIU Jisong; CHEN Liqiao; YING Xingang; WANG Ke

    2012-01-01

    The preparation of lead-free thick-film resistors are reported:using RuO2 and ruthenates as conductive particles,glass powders composed of B2O3,SiO2,CaO and Al2O3 as insulating phase,adding organic matter which mainly consists of ethyl cellulose and terpineol to form printable pastes.Resistors were fabricated and sintered by conventional screen-printing on 96%Al2O3 substrates,and then sintering in a belt furnace.X-ray diffraction (XRD) and electron scanning microscopy (SEM) have been used to characterize the conductive particles.The resistors exhibit good retiring stability and low temperature coefficient of resistance.Sheet resistance spans from about 80 Ω/□ to 600 Ω/□.The resistors prepared are qualified for common use.

  3. Development of metal oxide impregnated stilbite thick film ethanol sensor

    Energy Technology Data Exchange (ETDEWEB)

    Mahabole, M. P., E-mail: kashinath.bogle@gmail.com; Lakhane, M. A.; Choudhari, A. L.; Khairnar, R. S. [School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded - 431606 (India)

    2016-05-06

    This paper presents the study of the sensing efficiency of Titanium oxide/ Stilbite and Copper oxide /Stilbite composites towards detection of hazardous pollutants like ethanol. Stilbite based composites are prepared by physically mixing zeolite with metal oxides namely TiO{sub 2} and CuO with weight ratios of 25:75, 50:50 and 75:25. The resulting sensor materials are characterized by X-ray diffraction and Fourier Transform Infrared Spectroscopy techniques. Composite sensors are fabricated in the form of thick film by using screen printing technique. The effect of metal oxide concentration on various ethanol sensing parameters such as operating temperature, maximum uptake capacity and response/recovery time are investigated. The results indicate that metal oxide impregnated stilbite composites have great potential as low temperature ethanol sensor.

  4. The effect of grain size and film thickness on the thermal expansion coefficient of copper thin films.

    Science.gov (United States)

    Hwang, Seulgi; Kim, Youngman

    2011-02-01

    Cu thin films underwent thermal cycling to determine their coefficient of thermal expansion (CTE). The thermal stress of the Cu thin films with various microstructures (different grain size and film thickness) was measured using a curvature measurement system. The thermal expansion coefficients of the films were obtained from the slope of the stress-temperature curve with the knowledge of the Young's modulus and Poisson's ratio. The change in thermal stress with temperature of the Cu thin films tended to decrease with increasing grain size, resulting in an increase in the CTE. The thickness of Cu thin film had little effect on the thermal stress or the CTE.

  5. In vivo tear film thickness measurement and tear film dynamics visualization using spectral domain optical coherence tomography.

    Science.gov (United States)

    Aranha Dos Santos, Valentin; Schmetterer, Leopold; Gröschl, Martin; Garhofer, Gerhard; Schmidl, Doreen; Kucera, Martin; Unterhuber, Angelika; Hermand, Jean-Pierre; Werkmeister, René M

    2015-08-10

    Dry eye syndrome is a highly prevalent disease of the ocular surface characterized by an instability of the tear film. Traditional methods used for the evaluation of tear film stability are invasive or show limited repeatability. Here we propose a new non-invasive fully automated approach to measure tear film thickness based on spectral domain optical coherence tomography and on an efficient delay estimator. Silicon wafer phantom were used to validate the thickness measurement. The technique was applied in vivo in healthy subjects. Series of tear film thickness maps were generated, allowing for the visualization of tear film dynamics. Our results show that the in vivo central tear film thickness measurements are precise and repeatable with a coefficient of variation of about 0.65% and that repeatable tear film dynamics can be observed. The presented approach could be used in clinical setting to study patients with dry eye disease and monitor their treatments.

  6. The application of the barrier-type anodic oxidation method to thickness testing of aluminum films

    Science.gov (United States)

    Chen, Jianwen; Yao, Manwen; Xiao, Ruihua; Yang, Pengfei; Hu, Baofu; Yao, Xi

    2014-09-01

    The thickness of the active metal oxide film formed from a barrier-type anodizing process is directly proportional to its formation voltage. The thickness of the consumed portion of the metal film is also corresponding to the formation voltage. This principle can be applied to the thickness test of the metal films. If the metal film is growing on a dielectric substrate, when the metal film is exhausted in an anodizing process, because of the high electrical resistance of the formed oxide film, a sudden increase of the recorded voltage during the anodizing process would occur. Then, the thickness of the metal film can be determined from this voltage. As an example, aluminum films are tested and discussed in this work. This method is quite simple and is easy to perform with high precision.

  7. Thin-film-formation study of high-Tc superconductors by resistive evaporation

    Science.gov (United States)

    Azoulay, Jacob

    1991-10-01

    Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O thin films were prepared with use of a conventional vacuum system for the evaporation of the constituents. This method produces stoichiometric films upon complete evaporation of the constituents. No thickness monitor or any other control system is required. In this study, substrates were kept at room temperature during the evaporation process. The bismuth-based thin films are shown to lose bismuth during heat treatment unless the Cu constituent is evaporated last and fully oxidized at 400 °C subsequently. Y-Ba-Cu-O films prepared by using a pulverized mixture of Y, BaF2, and Cu constituents show an improved quality over films obtained from YF3, BaF2, and Cu starting materials. This improvement is attributed to fluorine reduction in the starting-material mixture.

  8. Thin-film-formation study of high- T sub c superconductors by resistive evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, J. (Center for Technological Education Holon, P.O. Box 305, Holon 58102 (Israel) Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel))

    1991-10-01

    Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O thin films were prepared with use of a conventional vacuum system for the evaporation of the constituents. This method produces stoichiometric films upon complete evaporation of the constituents. No thickness monitor or any other control system is required. In this study, substrates were kept at room temperature during the evaporation process. The bismuth-based thin films are shown to lose bismuth during heat treatment unless the Cu constituent is evaporated last and fully oxidized at 400 {degree}C subsequently. Y-Ba-Cu-O films prepared by using a pulverized mixture of Y, BaF{sub 2}, and Cu constituents show an improved quality over films obtained from YF{sub 3}, BaF{sub 2}, and Cu starting materials. This improvement is attributed to fluorine reduction in the starting-material mixture.

  9. CO2 Selective Potentiometric Sensor in Thick-film Technology

    Directory of Open Access Journals (Sweden)

    Ralf Moos

    2008-08-01

    Full Text Available A potentiometric sensor device based on screen-printed Nasicon films was investigated. In order to transfer the promising sensor concept of an open sodium titanate reference to thick film technology, “sodium-rich” and “sodium-poor” formulations were compared. While the “sodium-rich” composition was found to react with the ion conducting Nasicon during thermal treatment, the “sodium-poor” reference mixture was identified as an appropriate reference composition. Screen-printed sensor devices were prepared and tested with respect to CO2 response, reproducibility, and cross-interference of oxygen. Excellent agreement with the theory was observed. With the integration of a screen-printed heater, sensor elements were operated actively heated in a cold gas stream.

  10. Charge transport in films of Geobacter sulfurreducens on graphite electrodes as a function of film thickness

    KAUST Repository

    Jana, Partha Sarathi

    2014-01-01

    Harnessing, and understanding the mechanisms of growth and activity of, biofilms of electroactive bacteria (EAB) on solid electrodes is of increasing interest, for application to microbial fuel and electrolysis cells. Microbial electrochemical cell technology can be used to generate electricity, or higher value chemicals, from organic waste. The capability of biofilms of electroactive bacteria to transfer electrons to solid anodes is a key feature of this emerging technology, yet the electron transfer mechanism is not fully characterized as yet. Acetate oxidation current generated from biofilms of an EAB, Geobacter sulfurreducens, on graphite electrodes as a function of time does not correlate with film thickness. Values of film thickness, and the number and local concentration of electrically connected redox sites within Geobacter sulfurreducens biofilms as well as a charge transport diffusion co-efficient for the biofilm can be estimated from non-turnover voltammetry. The thicker biofilms, of 50 ± 9 μm, display higher charge transport diffusion co-efficient than that in thinner films, as increased film porosity of these films improves ion transport, required to maintain electro-neutrality upon electrolysis. This journal is © the Partner Organisations 2014.

  11. Imaging the anisotropic nonlinear meissner effect in nodal YBa2 Cu3 O7-δ thin-film superconductors.

    Science.gov (United States)

    Zhuravel, Alexander P; Ghamsari, B G; Kurter, C; Jung, P; Remillard, S; Abrahams, J; Lukashenko, A V; Ustinov, Alexey V; Anlage, Steven M

    2013-02-22

    We have directly imaged the anisotropic nonlinear Meissner effect in an unconventional superconductor through the nonlinear electrodynamic response of both (bulk) gap nodes and (surface) Andreev bound states. A superconducting thin film is patterned into a compact self-resonant spiral structure, excited near resonance in the radio-frequency range, and scanned with a focused laser beam perturbation. At low temperatures, direction-dependent nonlinearities in the reactive and resistive properties of the resonator create photoresponse that maps out the directions of nodes, or of bound states associated with these nodes, on the Fermi surface of the superconductor. The method is demonstrated on the nodal superconductor YBa2Cu3O7-δ and the results are consistent with theoretical predictions for the bulk and surface contributions.

  12. Novel Ballistic Processing of Sn-0.7Cu Thick Films

    Science.gov (United States)

    Cavero, D.; Stewart, K.; Morsi, K.

    2016-11-01

    The present paper discusses a novel process (Ballistic Processing) for the ultra-rapid processing of textured and un-textured thick and potentially thin films. The effect of processing velocity (14.6 to 36.1 m/s) on the developed external structure and internal microstructure of Sn-0.7Cu thick film is discussed. Film thicknesses ranging from 6.08 to 12.79 μm were produced and characterized by two-dimensional hypoeutectic microstructures. Both film thickness and dendrite arm spacing decreased with an increase in processing velocity.

  13. Thick-film acoustic emission sensors for use in structurally integrated condition-monitoring applications.

    Science.gov (United States)

    Pickwell, Andrew J; Dorey, Robert A; Mba, David

    2011-09-01

    Monitoring the condition of complex engineering structures is an important aspect of modern engineering, eliminating unnecessary work and enabling planned maintenance, preventing failure. Acoustic emissions (AE) testing is one method of implementing continuous nondestructive structural health monitoring. A novel thick-film (17.6 μm) AE sensor is presented. Lead zirconate titanate thick films were fabricated using a powder/sol composite ink deposition technique and mechanically patterned to form a discrete thick-film piezoelectric AE sensor. The thick-film sensor was benchmarked against a commercial AE device and was found to exhibit comparable responses to simulated acoustic emissions.

  14. Non-linear dynamics of inlet film thickness during unsteady rolling process

    Science.gov (United States)

    Fu, Kuo; Zang, Yong; Gao, Zhiying; Qin, Qin; Wu, Diping

    2016-05-01

    The inlet film thickness directly affects film and stress distribution of rolling interfaces. Unsteady factors, such as unsteady back tension, may disturb the inlet film thickness. However, the current models of unsteady inlet film thickness lack unsteady disturbance factors and do not take surface topography into consideration. In this paper, based on the hydrodynamic analysis of inlet zone an unsteady rolling film model which concerns the direction of surface topography is built up. Considering the small fluctuation of inlet angle, absolute reduction, reduction ratio, inlet strip thickness and roll radius as the input variables and the fluctuation of inlet film thickness as the output variable, the non-linear relationship between the input and output is discussed. The discussion results show that there is 180° phase difference between the inlet film thickness and the input variables, such as the fluctuant absolute reduction, the fluctuant reduction ratio and non-uniform inlet strip thickness, but there is no phase difference between unsteady roll radius and the output. The inlet angle, the steady roll radius and the direction of surface topography have significant influence on the fluctuant amplitude of unsteady inlet film thickness. This study proposes an analysis method for unsteady inlet film thickness which takes surface topography and new disturbance factors into consideration.

  15. Microstructure and texture analysis of YBCO thick film with peritectic growth on unoriented silver substrate

    Institute of Scientific and Technical Information of China (English)

    WANG Jue; MALOUFI Nabila; FAN Zhanguo; XUE Xiangxin; ESLING Claude

    2009-01-01

    YBCO textured thick film was prepared by direct periteetic growth method. Microstructure of the film was characterized. Electron backscattered diffraction (EBSD) technique was applied to the film for quantitative texture analysis. The main difficulty in resolving the ori-entation of YBCO pseudo-cubic structure was investigated. Automated orientation mapping was performed on YBCO thick film. Local tex-ture was presented in the form of orientation maps. Misorientation distribution and crystal growth characterization in the YBCO thick film were revealed. Large domains with well-aligned YBCO grains were formed. Each domain presented clear in-plane and out-plane textures.

  16. Thickness dependent CARS measurement of polymeric thin films without depth-profiling.

    Science.gov (United States)

    Choi, Dae Sik; Jeoung, Sae Chae; Chon, Byung-Hyuk

    2008-02-18

    Coherent anti-Stokes Raman scattering (CARS) microscopy is demonstrated to be a promising optical method for the characterization of polymer films with film thickness varying between 180 nm to 4300 nm. In case of PMMA films with a thickness of few hundreds of nanometers, the observed CARS signal was mainly associated with the interference effect of large nonresonant CARS field from glass substrate and the weak resonant field of PMMA. The dependence of resonant CARS intensity of PMMA film on film thickness is in good agreement with the theoretical prediction on a CARS field. The current work offers potential possibilities of noninvasive thickness measurement of polymeric thin film of thickness less than 180 nm by multiplex CARS microscopy without depth-profiling.

  17. Development of Dual-light Path Monitoring System of Optical Thin-film Thickness

    Institute of Scientific and Technical Information of China (English)

    XU Shi-jun

    2005-01-01

    The accurate monitoring of optical thin-film thickness is a key technique for depositing optical thin-film. For existing coating equipments, which are low precision and automation level on monitoring thin-film thickness, a new photoelectric control and analysis system has been developed. In the new system, main techniques include a photoelectric system with dual-light path, a dual-lock-phase circuit system and a comprehensive digital processing-control-analysis system.The test results of new system show that the static and dynamic stabilities and the control precision of thin-film thickness are extremely increased. The standard deviation of thin-film thickness, which indicates the duplication of thin-film thickness monitoring, is equal to or less than 0.72%. The display resolution limit on reflectivity is 0.02 %. In the system, the linearity of drift is very high, and the static drift ratio approaches zero.

  18. Preparation and characterization of microcrack-free thick YBa2Cu3O7-δ films

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    High quality epitaxial YBa2Cu3O7-δ (YBCO) superconducting films were fabricated on (00l) LaAlO3 substrates using the direct-current sputtering method. The attainment of an unusually high film thickness (up to 2.0 μm) without microcracking was attributed in part to the presence of pores correlated with yttrium-rich composition in the films. The influence of the film thickness on the microstructure was investigated by X-ray diffraction conventional scan (θ-2θ, ω-scan, pole figure) and high-resolution reciprocal space mapping. The films were c-axis oriented with no a-axis-oriented grains up to the thickness of 2 μm. The surface morphology and the critical current density (Jc) strongly depended on the film thickness.Furthermore, the reasons for these thickness dependences were elucidated in derail.

  19. Layer-by-layer assembly of nanocomposite films with thickness up to hundreds of nanometers

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ling-de; YAN Yu-hua; YU Hai-hu; GU Er-dan; JIANG De-sheng

    2006-01-01

    Polyelectrolyte/polyelectrolyte, organic molecule/colloidal CdS and polyelectrolyte/MWCNT films were fabricated via the layer-by-layer assembling technique. The assembled films were characterized by UV-vis spectrophotometer, X-ray diffractometry,nano profilometer and scanning electron microscopy. The results demonstrate that the layer-by-layer assembling technique can be used to make the nanoscaled films from polyelectrolytes and thicker composite films from suitable precursor materials. Both organic molecule/colloidal CdS films and PEI/MWCNT films with thickness of hundreds of nanometers were obtained. For the organic molecule/colloidal CdS films, a reasonable explanation for the result is that both the organic molecules and the CdS particles aggregate in the films. For the PEI/MWCNT films, obviously, it is the MWCNT that makes the great contribution to the film thickness.

  20. Mechanism of thickness dependence of critical current density in HTS YBCO film and its elimination using nano-engineering

    Science.gov (United States)

    Wang, Xiang

    The most promising characteristic of a High Temperature Superconductor (HTS) is its ability to carry larger electrical current at liquid nitrogen boiling temperature and strong applied magnetic field with minimal dissipation. Numerous large scale applications such as HTS transmission cables, HTS magnets and HTS motors have been developed using HTS materials. The major limitation that prevents its wide commercialization is its high cost-to-performance ratio. However, the effort to further improve HTS current carrying capability is jeopardized by a mysterious thickness dependence of the critical current density (Jc) --- Jc monotonically decreases with increasing thickness (t) at 77 K and self-field (SF). This poses a great challenge for both HTS applications and the understanding of vortex dynamics. What further complicates this issue is the complex defect structure in HTS films as well as the creep nature of magnetic vortices at a finite temperature. After a systematic study of the temperature and magnetic field effects on Jc--t, we conclude that Jc--t is most likely the result of a collective pinning effect dictated by a random pinning potential. Besides that, thermal fluctuations also alter Jc--t in a predictable way. Therefore, by either modifying the vortex structure or pinning structure, J c--t can be eliminated. Indeed, a thin film J c has been restored in a HTS/insulator/HTS trilayer while the magnetic coupling is weakened. Moreover, Jc--t has been removed when the random distributed point pins are overpowered by strong linear defects.

  1. Thickness dependence of the triplet spin-valve effect in superconductor-ferromagnet heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Lenk, Daniel; Zdravkov, Vladimir I.; Kehrle, Jan; Obermeier, Guenther; Krug von Nidda, Hans-Albrecht; Mueller, Claus; Horn, Siegfried; Tidecks, Reinhard [Institut fuer Physik, Universitaet Augsburg (Germany); Morari, Roman [Institut fuer Physik, Universitaet Augsburg (Germany); D. Ghitsu Institute of Electronic Engineering and Nanotechnologies ASM, Kishinev (Moldova, Republic of); Sidorenko, Anatolie S. [D. Ghitsu Institute of Electronic Engineering and Nanotechnologies ASM, Kishinev (Moldova, Republic of); Tagirov, Lenar [Solid State Physics Department, Kazan Federal University (Russian Federation)

    2015-07-01

    We investigated the triplet spin-valve effect in nanoscale layered S/F{sub 1}/N/F{sub 2}/AF heterostructures with varying F{sub 1}-layer thickness (where S=Nb is a singlet superconducting, F{sub 1}=Cu{sub 41}Ni{sub 59} and F{sub 2}=Co a ferromagnetic, and N a normal-conducting, non-magnetic layer). The theory predicts a long-range, odd-in-frequency triplet component of superconductivity at non-collinear alignment of the magnetizations of F{sub 1} and F{sub 2}. This triplet component exhausts the singlet state and, thus, lowers the superconducting transition temperature, T{sub c}, yielding a global minimum of T{sub c} close to the perpendicular mutual orientations of the magnetizations. We found an oscillating decay of T{sub c} suppression, due to the generation of the triplet component, with increasing F{sub 1} layer thickness, which we discuss in the framework of recent theories.

  2. Prototype Superconducting Planar Transformers Using High-Tc Thin and Thick Films

    Science.gov (United States)

    1992-01-01

    Japanese Journal of Applied Physics , vol...Diffraction Pattern of Superconductor Bi 2 (Sr,Ca) 3-.Cu 2Oy," Japanese Journal of Applied Physics , vol. 27, p. L833. Peterson, R.L., and J.W. Ekin. 1988...34Crystallinity and Morphology of Superconducting Thin Films Prepared by Sputtering," Japanese Journal of Applied Physics , vol. 28, p. L441. Tarascon,

  3. atomic layer deposition of amorphous niobium carbide-based thin film superconductors.

    Energy Technology Data Exchange (ETDEWEB)

    Prolier, T.; Klug, J. A.; Elam, J. W.; Claus, H.; Becker, N. G.; Pellin, M. J. (Materials Science Division)

    2011-01-01

    Niobium carbide thin films were synthesized by atomic layer deposition (ALD) using trimethylaluminum (TMA), NbF{sub 5}, and NbCl{sub 5} precursors. In situ quartz crystal microbalance (QCM) measurements performed at 200 and 290 C revealed controlled, linear deposition with a high growth rate of 5.7 and 4.5 {angstrom}/cycle, respectively. The chemical composition, growth rate, structure, and electronic properties of the films were studied over the deposition temperature range 125-350 C. Varying amounts of impurities, including amorphous carbon (a-C), AlF{sub 3}, NbF{sub x}, and NbCl{sub x}, were found in all samples. A strong growth temperature dependence of film composition, growth rate, and room temperature DC resistivity was observed. Increasing film density, decreasing total impurity concentration, and decreasing resistivity were observed as a function of increasing deposition temperature for films grown with either NbF{sub 5} or NbCl{sub 5}. Superconducting quantum interference device (SQUID) magnetometry measurements down to 1.2 K revealed a superconducting transition at T{sub c} = 1.8 K in a 75 nm thick film grown at 350 C with TMA and NbF{sub 5}. The superconducting critical temperature could be increased up to 3.8 K with additional use of NH{sub 3} during ALD film growth.

  4. Atomic layer deposition of amorphous niobium carbide-based thin film superconductors.

    Energy Technology Data Exchange (ETDEWEB)

    Klug, J. A.; Prolier, T.; Elam, J. W.; Becker, N. G.; Pellin, M. J. (Energy Systems); ( HEP); ( MSD); (Illinois Inst. Tech.)

    2011-01-01

    Niobium carbide thin films were synthesized by atomic layer deposition (ALD) using trimethylaluminum (TMA), NbF{sub 5}, and NbCl{sub 5} precursors. In situ quartz crystal microbalance (QCM) measurements performed at 200 and 290 C revealed controlled, linear deposition with a high growth rate of 5.7 and 4.5 {angstrom}/cycle, respectively. The chemical composition, growth rate, structure, and electronic properties of the films were studied over the deposition temperature range 125-350 C. Varying amounts of impurities, including amorphous carbon (a-C), AlF{sub 3}, NbF{sub x}, and NbCl{sub x}, were found in all samples. A strong growth temperature dependence of film composition, growth rate, and room temperature DC resistivity was observed. Increasing film density, decreasing total impurity concentration, and decreasing resistivity were observed as a function of increasing deposition temperature for films grown with either NbF{sub 5} or NbCl{sub 5}. Superconducting quantum interference device (SQUID) magnetometry measurements down to 1.2 K revealed a superconducting transition at T{sub c} = 1.8 K in a 75 nm thick film grown at 350 C with TMA and NbF{sub 5}. The superconducting critical temperature could be increased up to 3.8 K with additional use of NH{sub 3} during ALD film growth.

  5. Investigation of Top/Bottom electrode and Diffusion Barrier Layer for PZT Thick Film MEMS Sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Pedersen, Thomas; Thomsen, Erik Vilain

    2008-01-01

    Top and bottom electrodes for screen printed piezoelectric lead zirconate titanate, Pb(ZrxTi1 - x)O3 (PZT) thick film are investigated with respect to future MEMS devices. Down to 100 nm thick E-beam evaporated Al and Pt films are patterned as top electrodes on the PZT using a lift-off process...

  6. On the film thickness of grease-lubricated contacts at low speed

    NARCIS (Netherlands)

    Cen, H.; Lugt, Pieter Martin; Morales-Espejel, G.E.

    2014-01-01

    The contribution of the thickener to the thickness of the lubricating film in grease-lubricated contacts is investigated. Four different types of greases were tested in a ball/spherical roller-on-disc machine, where the film thickness was measured using the interferometry method, varying the tempera

  7. Raman micro-spectroscopy for quantitative thickness measurement of nanometer thin polymer films

    NARCIS (Netherlands)

    Liszka, Barbara M.; Lenferink, Aufried T.M.; Witkamp, Geert-Jan; Otto, Cees

    2015-01-01

    The sensitivity of far-field Raman micro-spectroscopy was investigated to determine quantitatively the actual thickness of organic thin films. It is shown that the thickness of organic films can be quantitatively determined down to 3 nm with an error margin of 20% and down to 1.5 nm with an error ma

  8. Piezoelectric ceramic thick films deposited on silicon substrates by screen printing

    Science.gov (United States)

    Yao, Kui; He, Xujiang; Xu, Yuan; Chen, Meima

    2004-07-01

    Screen-printing processes offer advantages in producing directly patterned and integrated piezoelectric elements, and fill an important technological gap between thin film and bulk ceramics. However, several existing problems in the screen-printed piezoelectric thick films, such as the poor reliability and the required high sintering temperature, are significantly limiting their applications. In this work, lead zirconate titanate (PZT) ceramic films of 30 μm in thickness were deposited on Pt-coated silicon substrates by the screen-printing process, in which the ceramic pastes were prepared through a chemical liquid-phase doping approach. Porous thick films with good adhesion were formed on the substrates at a temperature of 925°C. Stable out-of-plane piezoelectric vibration of the thick films was observed with a laser scanning vibrometer (LSV), and the piezoelectric dilatation magnitude was determined accordingly. Our piezoelectric measurements through the areal displacement detection with LSV exhibited distinct advantages for piezoelectric film characterization, including high reliability, high efficiency, and comprehensive information. The longitudinal piezoelectric coefficients of the thick films were calculated from the measured dilatation data through a numerical simulation. High piezoelectric voltage constants were obtained due to the very low dielectric constant of the porous thick films. The application potentials of our screen-printed thick films as integrated piezoelectric sensors are discussed.

  9. In-Situ Synchrotron X-ray Study of the Phase and Texture Evolution of Ceria and Superconductor Films Deposited by Chemical Solution Method

    DEFF Research Database (Denmark)

    Yue, Zhao; Grivel, Jean-Claude; He, Dong

    2012-01-01

    In situ synchrotron x-ray diffraction is used to study the phase and texture formation of ceria based films and superconductor films deposited by the chemical solution method on technical substrates. Combined analysis using in situ synchrotron x-ray diffraction, thermogravimetry/differential ther......In situ synchrotron x-ray diffraction is used to study the phase and texture formation of ceria based films and superconductor films deposited by the chemical solution method on technical substrates. Combined analysis using in situ synchrotron x-ray diffraction, thermogravimetry...

  10. High-frequency applications of high-temperature superconductor thin films

    Science.gov (United States)

    Klein, N.

    2002-10-01

    High-temperature superconducting thin films offer unique properties which can be utilized for a variety of high-frequency device applications in many areas related to the strongly progressing market of information technology. One important property is an exceptionally low level of microwave absorption at temperatures attainable with low power cryocoolers. This unique property has initiated the development of various novel type of microwave devices and commercialized subsystems with special emphasis on application in advanced microwave communication systems. The second important achievement related to efforts in oxide thin and multilayer technology was the reproducible fabrication of low-noise Josephson junctions in high-temperature superconducting thin films. As a consequence of this achievement, several novel nonlinear high-frequency devices, most of them exploiting the unique features of the ac Josephson effect, have been developed and found to exhibit challenging properties to be utilized in basic metrology and Terahertz technology. On the longer timescale, the achievements in integrated high-temperature superconductor circuit technology may offer a strong potential for the development of digital devices with possible clock frequencies in the range of 100 GHz.

  11. Effect of thickness on electrical properties of SILAR deposited SnS thin films

    Science.gov (United States)

    Akaltun, Yunus; Astam, Aykut; Cerhan, Asena; ćayir, Tuba

    2016-03-01

    Tin sulfide (SnS) thin films of different thickness were prepared on glass substrates by successive ionic layer adsorption and reaction (SILAR) method at room temperature using tin (II) chloride and sodium sulfide aqueous solutions. The thicknesses of the films were determined using spectroscopic ellipsometry measurements and found to be 47.2, 65.8, 111.0, and 128.7nm for 20, 25, 30 and 35 deposition cycles respectively. The electrical properties of the films were investigated using d.c. two-point probe method at room temperature and the results showed that the resistivity was found to decrease with increasing film thickness.

  12. Measurement of the refractive index and thickness for infrared optical films deposited on rough substrates.

    Science.gov (United States)

    Saito, M; Nakamura, S; Miyagi, M

    1992-10-01

    A novel method is proposed to evaluate the refractive index and thickness of dielectric thin films in the infrared wavelength range. The method is useful for measurement of thin films that are formed on such rough substrates as metal plates, since it utilizes only the wavelengths of interference peaks, which is slightly affected by surface roughness of the sample. The method was applied to the measurement of germanium, zinc selenide, and lead fluoride films deposited on copper substrates. Measured thicknesses agreed well with the values that were obtained by ellipsometry, and refractive indices exhibited a tendency to increase with the film thickness.

  13. Laser desorption of NO from a thick C 60 film

    Science.gov (United States)

    Hoger, T.; Marzok, C.; Jongma, R. T.; Zacharias, H.

    2006-09-01

    The desorption of NO molecules from a thick C 60 film is reported. A thermal desorption spectrum indicates two adsorption sites with binding energies of Eb = 0.30 eV and 0.55 eV. For laser desorption the fullerene surface is exposed to NO and excited by 7 ns UV laser pulses. Desorbing NO molecules are recorded state selectively as well as time resolved. The time-of-flight measurement indicates three different desorption pathways. A fast channel shows rovibronic temperatures of Trot( v″ = 0) = 370 K, Trot( v″ = 1) = 390 K and Tvib = 610 K as well as strong rotational-translational coupling. The desorption yield for the fast channel increases linearly with pulse energy with a desorption cross section of σ = (5.1 ± 0.9) × 10 -17 cm 2. Dominating the signal for small J″ values is a slow channel with low rotational and translational temperatures of about 110 K. We assign this peak to a laser-induced thermal desorption. For large pump-probe delays the data deviate from the Maxwellian flux distribution and a third channel appears with extremely late arrival times.

  14. Relationship between Supplied Oil Flow Rates and Oil Film Thicknesses under Starved Elastohydrodynamic Lubrication

    Directory of Open Access Journals (Sweden)

    Taisuke Maruyama

    2015-04-01

    Full Text Available Many studies have already considered starved lubrication. However, there have been no reports on the oil film thicknesses under steady starved EHL (elastohydrodynamic lubrication, where the ultra-low volume of oil supplied per unit time is uniform. The present study examined the relationship between the supplied oil flow rate and oil film thickness under steady starved lubrication. A ball-on-disk testing machine was used in experiments to measure the oil film thickness by means of optical interferometry. A microsyringe pump was used to accurately control the supplied oil flow rate. The supplied oil flow rate was kept constant, and the minimum oil film thickness was measured for 1 h after the start of the tests to determine the relationship between the supplied oil flow rate and oil film thickness.

  15. Enhanced piezoelectric performance of composite sol-gel thick films evaluated using piezoresponse force microscopy.

    Science.gov (United States)

    Liu, Yuanming; Lam, Kwok Ho; Kirk Shung, K; Li, Jiangyu; Zhou, Qifa

    2013-05-14

    Conventional composite sol-gel method has been modified to enhance the piezoelectric performance of ceramic thick films. Lead zirconate titanate (PZT) and lead magnesium niobate-lead titanate (PMN-PT) thick films were fabricated using the modified sol-gel method for ultrasonic transducer applications. In this work, piezoresponse force microscopy was employed to evaluate the piezoelectric characteristics of PZT and PMN-PT composite sol-gel thick films. The images of the piezoelectric response and the strain-electric field hysteresis loop behavior were measured. The effective piezoelectric coefficient (d33,eff) of the films was determined from the measured loop data. It was found that the effective local piezoelectric coefficient of both PZT and PMN-PT composite films is comparable to that of their bulk ceramics. The promising results suggest that the modified composite sol-gel method is a promising way to prepare the high-quality, crack-free ceramic thick films.

  16. Preparation and characterisation of novel thick sol-gel titania film photocatalysts.

    Science.gov (United States)

    Mills, Andrew; Elliott, Nicholas; Hill, George; Fallis, David; Durrant, James R; Willis, Richard L

    2003-05-01

    The preparation and characterization of thick (9 microns), clear, mechanically robust and photocatalytically active films of nanocrystalline anatase titania are described. XRD and SEM analysis show the films comprise 13 nm particles of anatase TiO2. Thin (54 nm) films of the 'paste' TiO2, along with sol-gel titania films made by a more traditional route are also prepared and characterised. All titania films mediate the photocatalytic destruction of stearic acid with a quantum yield of 0.0016 +/- 0.0003, using either 365 nm (i.e. BLB) or 254 nm (germicidal) light. P25 TiO2 films also appear to mediate the same process with a similar formal quantum efficiency. Of all the films tested, the thick paste TiO2 films are the most ideally suited for use with near UV light, for reasons which are discussed. All the titania films tested exhibit photoinduced superhydrophilicity.

  17. Film Thickness and Flow Properties of Resin-Based Cements at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Bagheri R.

    2013-06-01

    Full Text Available Statement of Problem: For a luting agent to allow complete seating of prosthetic restorations, it must obtain an appropriate flow rate maintaining a minimum film thickness. The performance of recently introduced luting agents in this regard has not been evaluated. Purpose: To measure and compare the film thickness and flow properties of seven resin-containing luting cements at different temperatures (37°C, 25°C and10°C. Material and Methods: Specimens were prepared from five resin luting cements; seT (SDI, Panavia F (Kuraray, Varioloink II (Ivoclar, Maxcem (Kerr, Nexus2 (Kerr and two resin-modified glass-ionomer luting cements (RM-GICs; GC Fuji Plus (GC Corporation, and RelyX Luting 2 (3 M/ESPE. The film thickness and flow rate of each cement (n=15 was determined using the test described in ISO at three different temperatures. Results: There was a linear correlation between film thickness and flow rate for most of the materials. Cooling increased fluidity of almost all materials while the effect of temperature on film thickness was material dependent. At 37°C, all products revealed a film thickness of less than 25µm except for GC Fuji Plus. At 25°C, all cements pro-duced a film thickness of less than 27 µm except for seT. At 10°C, apart from seT and Rely X Luting 2, the remaining cements showed a film thickness smaller than 20 µm.Conclusion: Cooling increased fluidity of almost all materials, however. the film thickness did not exceed 35 µm in either condition, in spite of the lowest film thickness being demonstrated at the lowest temperature.

  18. Spectral characteristics of nanometer-thick chromium films in terahertz frequency range

    Science.gov (United States)

    Andreev, V. G.; Angeluts, A. A.; Vdovin, V. A.; Lukichev, V. F.

    2015-02-01

    The spectral characteristics (reflection, transmission, and absorption coefficients) of thin chromium films on silica substrates have been measured using a pulsed source of terahertz radiation. The spectra of optical coefficients were obtained in a frequency range of 0.25-1.1 THz. Dependences of the optical coefficients on the metal film thickness at 1 THz were constructed. The maximum absorption coefficient (43%) was observed at a film thickness of 10 nm.

  19. Effect of thickness and temperature of copper phthalocyanine films on their properties

    Directory of Open Access Journals (Sweden)

    Alieva Kh. S.

    2012-06-01

    Full Text Available The research has shown that copper phthalocyanine films, having a set of unique properties, can be successfully used as gas-sensitive coating of resistive structures. The thickness of the film, in contrast to its temperature, is not the determining factor for high sensitivity. Low operating temperature of structures with copper phthalocyanine films allows to exploit them in economy mode.

  20. Microstructural parameters and optical constants of ZnTe thin films with various thicknesses

    Science.gov (United States)

    Shaaban, Essam R.; Kansal, Ishu; Mohamed, S. H.; Ferreira, Joés M. F.

    2009-11-01

    Different thickness of polycrystalline ZnTe films have been deposited onto glass substrates at room temperature by vacuum evaporation technique. The structural characteristics studied by X-ray diffraction (XRD) showed that the films are polycrystalline and have a zinc blende (cubic) structure. The calculated microstructure parameters revealed that the crystallite size increases and microstrain decreases with increasing film thickness. The transmittance and reflectance have been measured at normal and near normal incidence, respectively, in the spectral range 400-2500 nm. For ZnTe films of different thicknesses, the dependence of absorption coefficient, α on the photon energy showed the occurrence of a direct transition with band gap energy Egopt=2.21±0.01 eV (For ZnTe films of different thicknesses) confirming the independency of deduced energy gap on film thickness. The refractive indices have been evaluated in terms of envelope method, which has been suggested by Swanepoul in the transparent region. The refractive index could be extrapolated by Cauchy dispersion relationship over the whole spectra range, which extended from 400 to 2500 nm. It was observed that the refractive index, n increased upon increasing the film thickness up to 508 nm, lying within the experimental error for further increases in film thickness.

  1. Thickness-dependent stress in plasma-deposited silicon dioxide films

    Science.gov (United States)

    Au, V.; Charles, C.; Bulla, D. A. P.; Love, J. D.; Boswell, R. W.

    2005-04-01

    Thick silicon dioxide (SiO2) films up to 5 μm have been deposited by helicon activated reactive evaporation (plasma assisted deposition with electron beam evaporation source) as both bilayer and trilayer structures, and the film stress was investigated in the context of optical waveguide fabrication. A model for stress in the SiO2-Si bilayer as a function of film thickness is formulated and interpreted in terms of Volmer-Weber film growth mechanisms. We find that island coalescence begins at a film thickness of less than 165 nm and continues until about 700 nm. Above approximately 1 μm thickness, the film continues growth as a continuous film. The stress in a deposited SiO2 film in an SiO2-Si-SiO2 trilayer structure was investigated by adapting the established Stoney's equation for a trilayer system, and comparing it with a thermally grown SiO2 trilayer. A constant value of stress is obtained for the deposited SiO2 film for film thickness >1μm which was consistently less than both measured and previously reported values of stress in thermally grown SiO2.

  2. Change in Tear Film Lipid Layer Thickness, Corneal Thickness, Volume and Topography after Superficial Cauterization for Conjunctivochalasis.

    Science.gov (United States)

    Chan, Tommy C Y; Ye, Cong; Ng, Paul K F; Li, Emmy Y M; Yuen, Hunter K L; Jhanji, Vishal

    2015-07-17

    We evaluated the change in tear film lipid layer thickness, corneal thickness, volume and topography after superficial cauterization of symptomatic conjunctivochalasis. Bilateral superficial conjunctival cauterization was performed in 36 eyes of 18 patients with symptomatic conjunctivochalasis. The mean age of patients (12 males, 6 females) was 68.6 ± 10.9 years (range: 44-83 years). Preoperatively, 28 eyes (77.8%) had grade 1 conjunctivochalasis, and 8 eyes (22.2%) had grade 2 conjunctivochalasis. At 1 month postoperatively, the severity of conjunctivochalasis decreased significantly (p corneal thickness, thinnest corneal thickness and corneal volume decreased significantly postoperatively (p corneal thickness and volume were observed after surgical correction of conjunctivochalasis.

  3. Intrinsic flux pinning mechanisms in different thickness MgB2 films

    Directory of Open Access Journals (Sweden)

    C. Yang

    2017-03-01

    Full Text Available MgB2 films in four thickness (60 nm, 200nm, 600nm and 1μm have been fabricated by hybrid physical–chemical vapor deposition technique (HPCVD. By measuring the magnetization hysteresis loops and the resistivity, we have obtained the transport and magnetic properties of the four films. After that, the pinning mechanisms in them were discussed. Comparing the pinning behaviors in these ultrathin films, thin films and thick films, it was found that there exist different pinning types in MgB2 films of different thickness. In combination with the study of the surface morphology, cross-section and XRD results, we concluded that MgB2 films had different growth modes in different growth stages. For thin films, films grew along c axis, and grain boundaries acted as surface pinning. While for thick films, films grew along c axis at first, and then changed to a-b axis growth. As a result, the a-b axis grains acted as strong volume pinning.

  4. Preparation and study of thickness dependent electrical characteristics of zinc sulfide thin films

    Indian Academy of Sciences (India)

    A U Ubale; D K Kulkarni

    2005-02-01

    Zinc sulfide thin films have been deposited onto glass substrates by chemical bath deposition. The various deposition parameters such as volume of sulfide ion source, pH of bath, deposition time, temperature etc are optimized. Thin films of ZnS with different thicknesses of 76–332 nm were prepared by changing the deposition time from 6–20 h at 30°C temperature. The effect of film thickness on structural and electrical properties was studied. The electrical resistivity was decreased from 1.83 × 105 -cm to 0.363 × 105 -cm as film thickness decreased from 332 nm to 76 nm. The structural and activation energy studies support this decrease in the resistivity due to improvement in crystallinity of the films which would increase the charge carrier mobility and decrease in defect levels with increase in the thickness.

  5. The preparation, processing and properties of thin and thick films for microelectric applications

    Science.gov (United States)

    Bagley, B. G.; Greene, L. H.; Barboux, P.; Tarascon, J. M.; Venkatesan, T.

    High-Tc thin and thick films of YBa2Cu2O(7-y) and thick films based on the Bi-Sr-Ca-Cu and Tl-Ba-Ca-Cu systems were prepared and their properties investigated. It was found that YB2Cu3O(7-y) thin films prepared at temperatures up to 400 C, have amorphous structures, and those prepared in the 400-650 C region exhibit polyphase microstructure, due to the rapid crystallization kinetics of the competing phases. Methods for bipassing the 'forbidden' temperature region are described. Preparation of YBa2Cu2O(7-y) thick films was achieved via an aqueous sol-gel technique. Bi-Sr-Ca-Cu- and Tl-Ba-Ca-Cu-based thick films were prepared via the decomposition of glycerol-based solutions containing nitrates of the elements.

  6. Correlation of Gear Surface Fatigue Lives to Lambda Ratio (Specific Film Thickness)

    Science.gov (United States)

    Krantz, Timothy Lewis

    2013-01-01

    The effect of the lubrication regime on gear performance has been recognized, qualitatively, for decades. Often the lubrication regime is characterized by the specific film thickness being the ratio of lubricant film thickness to the composite surface roughness. Three studies done at NASA to investigate gearing pitting life are revisited in this work. All tests were done at a common load. In one study, ground gears were tested using a variety of lubricants that included a range of viscosities, and therefore the gears operated with differing film thicknesses. In a second and third study, the performance of gears with ground teeth and superfinished teeth were assessed. Thicker oil films provided longer lives as did improved surface finish. These datasets were combined into a common dataset using the concept of specific film thickness. This unique dataset of more 258 tests provides gear designers with some qualitative information to make gear design decisions.

  7. Effect of thickness on nonlinear absorption properties of graphite oxide thin films

    Science.gov (United States)

    Sreeja, V. G.; Cheruvalathu, Ajina; Reshmi, R.; Anila, E. I.; Thomas, Sheenu; Jayaraj, M. K.

    2016-10-01

    We report the thickness dependent structural, linear and nonlinear optical properties of graphite oxide (GO) thin films synthesized by spin coating method. We observed that the structural, linear and nonlinear optical properties can be tuned by the film thickness in GO. The nonlinear absorption studies by open aperture z scan technique exhibited a saturable absorption. The nonlinear absorption coefficient and saturation intensity varies with film thickness which is attributed to increased localized defect states in the energy band gap. Our results emphasize relatively large thickness dependent optical nonlinearity of GO thin films and its potential for optical pulse generation, exploring the way to GO based nonlinear applications in Q switched mode locking laser systems. All the coated GO films were characterized by X-Ray diffraction method (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis absorption spectroscopy (UV-Vis), Photoluminescence (PL) and Scanning electron microscope (SEM) measurements.

  8. Studies on gas sensing performance of pure and modified barium strontium titanate thick film resistors

    Indian Academy of Sciences (India)

    G H Jain; L A Patil; P P Patil; U P Mulik; K R Patil

    2007-02-01

    Barium strontium titanate ((Ba0.87Sr0.13)TiO3–BST) ceramic powder was prepared by mechanochemical process. The thick films of different thicknesses of BST were prepared by screen-printing technique and gas-sensing performance of these films was tested for various gases. The films showed highest response and selectivity to ammonia gas. The effect of film thickness on gas response was also studied. As prepared BST thick films were surface modified by dipping them into an aqueous solution of titanium chloride (TiCl3) for different intervals of time. Surface modification shifted response to H2S gas suppressing the responses to ammonia and other gases. The surface modification, using dipping process, altered the adsorbate–adsorbent interactions, which gave the unusual sensitivity and selectivity effect. Sensitivity, selectivity, thermal stability, response and recovery time of the sensor were measured and presented.

  9. Effect of Nanotube Film Thickness on the Performance of Nanotube-Silicon Hybrid Solar Cells

    Science.gov (United States)

    Tune, Daniel D.; Shapter, Joseph G.

    2013-01-01

    The results of measurements on solar cells made from randomly aligned thin films of single walled carbon nanotubes (SWCNTs) on n-type monocrystalline silicon are presented. The films are made by vacuum filtration from aqueous TritonX-100 suspensions of large diameter arc-discharge SWCNTs. The dependence of the solar cell performance on the thickness of the SWCNT film is shown in detail, as is the variation in performance due to doping of the SWCNT film with SOCl2.

  10. Non-contacting Measurement of Oil Film Thickness Between Loaded Metallic Gear Teeth

    Science.gov (United States)

    Cox, Daniel B.; Ceccio, Steven L.; Dowling, David R.

    2013-11-01

    The mechanical power transmission efficiency of gears is depends on the lubrication condition between gear teeth. While the lubrication levels can be generally predicted, an effective in-situ non-contacting measurement of oil film thicknesses between loaded metallic gear teeth has proved elusive. This study explores a novel oil film thickness measurement technique based on optical fluence, the light energy transmitted between loaded gear teeth. A gear testing apparatus that allowed independent control of gear rotation rate, load torque, and oil flow was designed and built. Film thickness measurements made with 5-inch-pitch-diameter 60-tooth spur gears ranged from 0.3 to 10.2 mil. These results are compared with film thickness measurements made in an earlier investigation (MacConochie and Cameron, 1960), as well as with predictions from two film thickness models: a simple two-dimensional squeezed oil film and the industry-accepted model as described by the American Gear Manufacturers Association (AGMA 925, 2003). In each case, the measured film thicknesses were larger than the predicted thicknesses, though these discrepancies might be attributed to the specifics the experiments and to challenges associated with calibrating the fluence measurements. [Sponsored by General Electric].

  11. Influence of Thickness on Ethanol Sensing Characteristics of Doctor-bladed Thick Film from Flame-made ZnO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Sukon Phanichphant

    2007-02-01

    Full Text Available ZnO nanoparticles were produced by flame spray pyrolysis (FSP using zincnaphthenate as a precursor dissolved in toluene/acetonitrile (80/20 vol%. The particleproperties were analyzed by XRD, BET, and HR-TEM. The sensing films were produced bymixing the particles into an organic paste composed of terpineol and ethyl cellulose as avehicle binder and were fabricated by doctor-blade technique with various thicknesses (5,10, 15 μm. The morphology of the sensing films was analyzed by SEM and EDS analyses.The gas sensing characteristics to ethanol (25-250 ppm were evaluated as a function of filmthickness at 400°C in dry air. The relationship between thickness and ethanol sensingcharacteristics of ZnO thick film on Al2O3 substrate interdigitated with Au electrodes wereinvestigated. The effects of film thickness, as well as the cracking phenomenon, though,many cracks were observed for thicker sensing films. Crack widths increased withincreasing film thickness. The film thickness, cracking and ethanol concentration havesignificant effect on the sensing characteristics. The sensing characteristics with variousthicknesses were compared, showing the tendency of the sensitivity to ethanol decreasedwith increasing film thickness and response time. The relationship between gas sensingproperties and film thickness was discussed on the basis of diffusively and reactivity of thegases inside the oxide films. The thinnest sensing film (5 μm showed the highest sensitivityand the fastest response time (within seconds.

  12. Field electron emission from undoped, continuous, submicron-thick diamond films

    Science.gov (United States)

    Ternyak, O.; Akhvlediani, R.; Hoffman, A.; Wong, W. K.; Lee, S. T.; Lifshitz, Y.; Daren, S.; Cheifetz, E.

    2005-12-01

    The present work shows that the field electron emission (FEE) properties of polycrystalline diamond films can be enhanced by control over the film thickness. The FEE properties of undoped, continuous, and smooth submicron-thick diamond films with initial nucleation densities of ˜5×1010particles/cm2 were investigated as a function of diamond film thickness. A set of films with thickness ranging from 70-100to830nm yielded turn-on field values of 6-8V/μm and threshold field values of 8.5-17.5V/μm (for 0.3μA/cm2), respectively, without any conditioning. It was found that the films of thickness up to ˜370nm can sustain stable current density as high as 0.1A/cm2 without morphological modification. The thicker films, however, suffer from a strong degradation of the film and breakdown. The best FEE (lower turn-on and threshold fields and morphological stability) was obtained for a thin (100nm) continuous diamond film. This result is suggested to be attributed mainly to the efficient electron conduction from the back contact to the surface.

  13. Optical coefficients of nanometer-thick copper and gold films in microwave frequency range

    Science.gov (United States)

    Khorin, I.; Orlikovsky, N.; Rogozhin, A.; Tatarintsev, A.; Pronin, S.; Andreev, V.; Vdovin, V.

    2016-12-01

    Ultrathin (1-10 nm) Cu and Au films were prepared on the silicon and quartz substrates by magnetron sputtering at room temperature. We measured the transmission coefficient of the films at a wavelength of 3cm and analyzed a surface morphology of these films. It was shown that the films with thicknesses less than 7.5 nm (Au) and 3 nm (Cu) are almost transparent for microwaves. This effect is explained by quick oxidation of Cu and the complex surface morphology of nanometer thick films. The Au film morphology is evolved with increasing average Au thickness d from hemispherical islands initially (1.0 nm

  14. Evaluation of feasibility of measuring EHD film thickness associated with cryogenic fluids

    Science.gov (United States)

    Kannel, J. W.; Merriman, T. L.; Stockwell, R. D.; Dufrane, K. F.

    1983-08-01

    The feasibility of measuring elastohydrodynamic (EHD) films as formed with a cryogenic (LN2) fluid is evaluated. Modifications were made to an existing twin disk EHD apparatus to allow for disk lubrication with liquid nitrogen. This disk apparatus is equipped with an X-ray system for measuring the thickness of any lubricant film that is formed between the disks. Several film thickness experiments were conducted with the apparatus which indicate that good lubrication films are filmed with LN2. In addition to the film thickness studies, failure analyses of three bearings were conducted. The HPOTP turbine end bearings had experienced axial loads of 36,000 to 44,000 N (8,000 to 10,000 lb). High continuous radial loads were also experienced, which were most likely caused by thermal growth of the inner race. The resulting high internal loads caused race spalling and ball wear to occur.

  15. Effect of Thickness of Single-Phase Antimony and Tellurium Thin Films on Their Thermal Conductivities.

    Science.gov (United States)

    Park, No-Won; Park, Sang-In; Lee, Sang-Kwon

    2015-09-01

    We present the effects of film thickness and grain size on the out-of-plane thermal conductivities of single-phase Sb and Te thin films, which are of great interest for thermoelectric device applications. The thermal conductivities of the films were measured by the four-point-probe 3Ωo method, at room temperature. For this study, 50-, 100-, and 200-nm-thick Sb and Te thin films were prepared by electron-beam evaporation at room temperature. From the measured thermal conductivities, we evaluated that the average thermal conductivities of the Sb and Te thin films were 5.9-10.2 W/(m x K) and 0.8-1.2 W/(m x K), respectively, at room temperature. This result reveals that the thickness and grain size of each thin film strongly affect the modulation of its thermal conductivity at room temperature.

  16. Realistic reflectance spectrum of thin films covering a transparent optically thick substrate

    Energy Technology Data Exchange (ETDEWEB)

    Cesaria, M., E-mail: maura.cesaria@le.infn.it; Caricato, A. P.; Martino, M. [Department of Mathematics and Physics “Ennio De Giorgi,” University of Salento, Via Arnesano, I-73100 Lecce (Italy)

    2014-07-21

    A spectrophotometric strategy is presented and discussed for calculating realistically the reflectance spectrum of an absorbing film deposited over a thick transparent or semi-transparent substrate. The developed route exploits simple mathematics, has wide range of applicability (high-to-weak absorption regions and thick-to-ultrathin films), rules out numerical and curve-fitting procedures as well as model-functions, inherently accounts for the non-measurable contribution of the film-substrate interface as well as substrate backside, and describes the film reflectance spectrum as determined by the experimental situation (deposition approach and parameters). The reliability of the method is tested on films of a well-known material (indium tin oxide) by deliberately changing film thickness and structural quality through doping. Results are found consistent with usual information yielded by reflectance, its inherent relationship with scattering processes and contributions to the measured total reflectance.

  17. The Thickness Distribution of Oxidation Film on Tapered Pipe Surface in Dieless Drawing

    Directory of Open Access Journals (Sweden)

    Fang Qin

    2011-01-01

    Full Text Available The thickness distribution of oxidation film on the surface of AISI304 stainless steel tapered pipe, its influence factors, and the effect of metal matrix deformation on oxidation behavior during dieless drawing were studied in this paper. The results showed that oxidation rate was affected strongly by induction heating temperature and deformation degree. The thickness distribution of oxidation film was uneven and increased from the larger diameter end to the smaller diameter end along the axial direction of tapered pipe. When induction heating temperature raised or the distance between heat and cold sources was increased, or feed speed was decreased, oxidation rate was accelerated and oxidation film on the tapered pipe surface thickened significantly, due to massive cracks in oxidation film induced by deformation of metal matrix. The density and width of cracks in oxidation film were enlarged, and the thickness of oxidation film increased with the increase in deformation degree.

  18. In-situ spectroscopy and nanoscale electronics in superconductor-topological insulator hybrid devices: a combined thin film growth and quantum transport study

    NARCIS (Netherlands)

    Ngabonziza, Prosper

    2016-01-01

    In this dissertation, we presented a combined thin film growth and quantum transport study on superconductor topological insulator hybrid devices. Understanding of the electronic properties of topological insulators (TIs), their preparation in high quality thin film form and their interaction with o

  19. Abnormal Cutoff Thickness of Long-Range Surface Plasmon Polariton Modes Guided by Thin Metal Films

    Institute of Scientific and Technical Information of China (English)

    LIU Fang; RAO Yi; HUANG Yi-Dong; ZHANG Wei; PENG Jiang-De

    2007-01-01

    Long-range surface plasmon polariton(LRSPP) modes guided by a thin metal film surrounded by semi-infinite dielectrics with different refractive indices are studied.Our cMculation results show that the cutoff thickness of the metal film does not monotonically increase with refractive index difference △n between the SHbstrate and superstrate.Just because of this abnormal behaviour of cutoff thickness,the existence of LRSPP illustrates complicated situations in asymmetric configurations.For a certain metal film thickness,LRsPP may exist in one.two or three refractive index difference △n regions.

  20. Ultrasonic oil-film thickness measurement: An angular spectrum approach to assess performance limits

    OpenAIRE

    Zhang, J.; Drinkwater, B.W.; Dwyer-Joyce, R.S.

    2007-01-01

    The performance of ultrasonic oil-film thickness measurement in a ball bearing is quantified. A range of different viscosity oils (Shell T68, VG15, and VG5) are used to explore the lowest reflection coefficient and hence the thinnest oil-film thickness that the system can measure. The results show a minimum reflection coefficient of 0.07 for both oil VG15 and VG5 and 0.09 for oil T68 at 50 MHz. This corresponds to an oil-film thickness of 0.4 μm for T68 oil. An angular spectrum (or Fourier d...

  1. Ptychographic Imaging of Branched Colloidal Nanocrystals Embedded in Free-Standing Thick Polystyrene Films

    Science.gov (United States)

    de Caro, Liberato; Altamura, Davide; Arciniegas, Milena; Siliqi, Dritan; Kim, Mee R.; Sibillano, Teresa; Manna, Liberato; Giannini, Cinzia

    2016-01-01

    Research on composite materials is facing, among others, the challenging task of incorporating nanocrystals, and their superstructures, in polymer matrices. Electron microscopy can typically image nanometre-scale structures embedded in thin polymer films, but not in films that are micron size thick. Here, X-ray Ptychography was used to visualize, with a resolution of a few tens of nanometers, how CdSe/CdS octapod-shaped nanocrystals self-assemble in polystyrene films of 24 ± 4 μm, providing a unique means for non-destructive investigation of nanoparticles distribution and organization in thick polymer films.

  2. Phase thickness approach for determination of thin film refractive index dispersion from transmittance spectra

    Science.gov (United States)

    Nenkov, M. R.; Pencheva, T. G.

    2008-06-01

    A novel approach for determination of refractive index dispersion n(λ ) and thickness d of thin films of negligible absorption and weak dispersion is proposed. The calculation procedure is based on determination of the phase thickness of the film in the spectral region of measured transmittance data. All points of measured spectra are included in the calculations. Barium titanate and titanium oxide thin films are investigated and their n(λ ) and d are calculated. The approach is validated using Swanepoel's method and it is found to be applicable for relatively thinner films when measured transmittance spectra have one minimum and one maximum only.

  3. Impressive electromagnetic shielding effects exhibited by highly ordered, micrometer thick polyaniline films

    Science.gov (United States)

    Mohan, Ranjini R.; Varma, Sreekanth J.; Sankaran, Jayalekshmi

    2016-04-01

    The present work highlights the remarkably high shielding effectiveness of about 68 dB, exhibited by highly ordered and doped polyaniline films, in the microwave frequency range 4-12 GHz, obtained by self-stabilized dispersion polymerization as the synthesis route. The observed shielding effectiveness is found to depend quite sensitively on the electrical conducting properties, which are predominantly controlled by the nature and concentration of the dopants. The structural and morphological characterization of the films using XRD and TEM techniques reveals surprisingly high extent of crystallinity, which contributes significantly towards enhancing the electrical conductivity of the films. Most of the available reports on the microwave response of conducting polymer film samples deal with much thicker films, compared to the micrometer thick films of the present studies. The shielding effectiveness of acid doped, micrometer thick polyaniline films reported in the present work far exceeds most of the previously reported values and meets the commercial requirements.

  4. Gas Sensing Performance of Pure and Modified BST Thick Film Resistor

    Directory of Open Access Journals (Sweden)

    G. H. JAIN

    2008-04-01

    Full Text Available Barium Strontium Titanate (BST-(Ba0.87Sr0.13TiO3 ceramic powder was prepared by mechanochemical process. The thick films of different thicknesses of BST were prepared by screen-printing technique and gas-sensing performance of these films was tested for various gases. The films showed highest response and selectivity to ammonia gas. The pure BST film was surface modified by surfactant CrO3 by using dipping technique. The surface modified film suppresses the response to ammonia and enhances to H2S gas. The surface modification of films changes the adsorption-desorption relationship with the target gas and shifts its selectivity. The gas response, selectivity, response and recovery time of the pure and modified films were measured and presented.

  5. Thickness measurement of organic films using Compton scattering of characteristic X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Yun, E-mail: kjy@kaeri.re.kr [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 1045, Dukjin-dong Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Choi, Yong Suk; Park, Yong Joon; Song, Kyuseok [Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 1045, Dukjin-dong Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Jung, Sung-Hee [Division of Radioisotope R and D, Korea Atomic Energy Research Institute, Daedeok-daero 1045, Dukjin-dong Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Hussein, Esam M.A. [Laboratory for Threat Materials Detection, Department of Mechanical Engineering, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3 (Canada)

    2011-09-15

    An X-ray scattering method is presented for determining the thickness of an organic film placed on a steel substrate. The strong peaks of characteristic X-rays are taken as an advantage to measure the intensity of backscattered photons. It is shown that the intensity of Compton scattering of characteristic X-rays is proportional to film thickness, up to the thickness of 250 {mu}m of acrylic adhesive layers. In addition, the measurement time was 300 ms, providing a simple and convenient method for on-line for thickness monitoring.

  6. Miniaturized, Planar Ion-selective Electrodes Fabricated by Means of Thick-film Technology

    Directory of Open Access Journals (Sweden)

    Robert Koncki

    2006-04-01

    Full Text Available Various planar technologies are employed for developing solid-state sensorshaving low cost, small size and high reproducibility; thin- and thick-film technologies aremost suitable for such productions. Screen-printing is especially suitable due to itssimplicity, low-cost, high reproducibility and efficiency in large-scale production. Thistechnology enables the deposition of a thick layer and allows precise pattern control.Moreover, this is a highly economic technology, saving large amounts of the used inks. Inthe course of repetitions of the film-deposition procedure there is no waste of material dueto additivity of this thick-film technology. Finally, the thick films can be easily and quicklydeposited on inexpensive substrates. In this contribution, thick-film ion-selective electrodesbased on ionophores as well as crystalline ion-selective materials dedicated forpotentiometric measurements are demonstrated. Analytical parameters of these sensors arecomparable with those reported for conventional potentiometric electrodes. All mentionedthick-film strip electrodes have been totally fabricated in only one, fully automated thick-film technology, without any additional manual, chemical or electrochemical steps. In allcases simple, inexpensive, commercially available materials, i.e. flexible, plastic substratesand easily cured polymer-based pastes were used.

  7. Effect of thickness on structural and electrical properties of Al-doped ZnO films

    Energy Technology Data Exchange (ETDEWEB)

    Garcés, F.A., E-mail: felipe.garces@santafe-conicet.gov.ar [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Budini, N. [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Arce, R.D.; Schmidt, J.A. [Instituto de Física del Litoral (CONICET-UNL), Güemes 3450, Santa Fe S3000GLN (Argentina); Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829, Santa Fe S3000AOM (Argentina)

    2015-01-01

    In this work, we have investigated the influence of thickness on structural and electrical properties of Al-doped ZnO films. Transparent conducting oxide films were grown by the spray pyrolysis technique from precursors prepared via the sol–gel method. We determined the structural properties of the films by performing X-ray diffraction and mosaicity measurements, which evidenced an increase of disorder and inhomogeneity between crystalline domains as the films thickened. This behavior was contrasted with results obtained from electrical measurements and was attributed to plastic deformation of the films as their thickness increased. As a result, the carrier mobility, the optical gap and the activation energy are affected due to emerging grain boundaries and a higher degree of disorder. - Highlights: • Al-doped ZnO thin films on glass with different thicknessesFilm thickness affects the morphological and electrical properties. • Increasing time deposition allows modification of resistivity and Hall mobility. • Mosaicity between crystalline domains increases with film thickness.

  8. Systematic experimental study of pure shear type dielectric elastomer membranes with different electrode and film thicknesses

    Science.gov (United States)

    Hodgins, M.; Seelecke, S.

    2016-09-01

    An approach to reduce the voltage required for dielectric elastomer actuators is to reduce film thickness. However, if the electrode thickness is not similarly reduced, the electrode’s mechanical behavior can increasingly and negatively impact the overall actuator behavior. This effect is yet to be studied and quantified for pure shear type specimens; a type recommended in a recent DE standardization journal publication. Therefore, in this work, using pure shear specimens, a comparative study of membrane actuators of different film thickness (20, 50 and 100 μm) is performed. Electrodes of different thicknesses are screen printed and tested in a uniaxial test device. The stiffening effect due to the solid-state electrodes is demonstrated by performing force-elongation tests for specimens with and without electrodes. Additionally the importance of thin electrodes (relative to film thickness) was demonstrated through a number of electromechanical tests. Isotonic tests revealed a lower electro-mechanical sensitivity for the 20 μm film when compared with the 50 and 100 μm films. This was attributed to the relatively thick electrodes. Best actuation results were achieved when the total electrode thickness was at least 15x thinner than the dielectric membrane thickness.

  9. Thickness dependence of Jc (0) in MgB2 films

    Science.gov (United States)

    Chen, Yiling; Yang, Can; Jia, Chunyan; Feng, Qingrong; Gan, Zizhao

    2016-06-01

    MgB2 superconducting films, whose thicknesses range from 10 nm to 8 μm, have been fabricated on SiC substrates by hybrid physical-chemical vapor deposition (HPCVD) method. It is the first time that the Tc and the Jc of MgB2 films are studied on such a large scale. It is found that with the increasing of thickness, Tc elevates first and then keeps roughly stable except for some slight fluctuations, while Jc (5 K, 0 T) experiences a sharp increase followed by a relatively slow fall. The maximum Jc (5 K, 0 T) = 2.3 × 108 A cm-2 is obtained for 100 nm films, which is the experimental evidence for preparing high-quality MgB2 films by HPCVD method. Thus, this work may provide guidance on choosing the suitable thickness for applications. Meanwhile, the films prepared by us cover ultrathin films, thin films and thick films, so the study on them will bring a comprehensive understanding of MgB2 films.

  10. Thickness dependent ferromagnetism in thermally decomposed NiO thin films

    Science.gov (United States)

    Ravikumar, Patta; Kisan, Bhagaban; Perumal, Alagarsamy

    2016-11-01

    We report the effects of film thickness, annealing temperature and annealing environments on thermal decomposition behavior and resulting magnetic properties of NiO (t=50-300 nm) thin films. All the NiO films were prepared directly on thermally oxidized Si at ambient temperature using magnetron sputtering technique and post annealed at different temperatures (TA) under vacuum and oxygen atmospheres. As-deposited films exhibit face centered cubic structure with large lattice constant due to strain induced during sputtering process. With increasing TA, the lattice constant decreases due to the release of strain and thickness dependent thermal decomposition reaction of NiO into Ni has been observed for the NiO films annealed at 500 °C under vacuum condition. As a result, the antiferromagnetic nature of the as-deposited NiO films transforms into ferromagnetic one with dominant thickness dependent ferromagnetic behavior at room temperature. In addition, the existence of both Ni and NiO phases in the annealed NiO films shows noticeable exchange bias under field cooling condition. The behavior of thermal decomposition was not observed for the NiO films annealed under oxygen condition which results in no detectable change in the magnetic properties. The observed results are discussed on the basis of thickness dependent thermal decomposition in NiO films with increasing TA and changing annealing conditions.

  11. Amorphous Indium Selenide Thin Films Prepared by RF Sputtering: Thickness-Induced Characteristics.

    Science.gov (United States)

    Han, Myoung Yoo; Park, Yong Seob; Kim, Nam-Hoon

    2016-05-01

    The influence of indium composition, controlled by changing the film thickness, on the optical and electrical properties of amorphous indium selenide thin films was studied for the application of these materials as Cd-free buffer layers in CI(G)S solar cells. Indium selenide thin films were prepared using RF magnetron sputtering method. The indium composition of the amorphous indium selenide thin films was varied from 94.56 to 49.72 at% by increasing the film thickness from 30 to 70 nm. With a decrease in film thickness, the optical transmittance increased from 87.63% to 96.03% and Eg decreased from 3.048 to 2.875 eV. Carrier concentration and resistivity showed excellent values of ≥1015 cm(-3) and ≤ 10(4) Ω x cm, respectively. The conductivity type of the amorphous indium selenide thin films could be controlled by changing the film-thickness-induced amount of In. These results indicate the possibility of tuning the properties of amorphous indium selenide thin films by changing their composition for use as an alternate buffer layer material in CI(G)S solar cells.

  12. Influence of film thickness and In-doping on physical properties of CdS thin films

    Energy Technology Data Exchange (ETDEWEB)

    Butt, Sajid, E-mail: sajidarif@hotmail.com [Department of Materials Science and Engineering, Institute of Space Technology (IST), Islamabad 44000 (Pakistan); Thermal Transport Laboratory, School of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad (Pakistan); Shah, Nazar Abbas [Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Nazir, Adnan [Istituto Italiano di Tecnologia, Via Morego 30, I-16163 Genova (Italy); Ali, Zulfiqar [Optics Laboratories, P. O. Box 1021, Islamabad (Pakistan); Maqsood, Asghri [CESET, Center for Emerging Sciences, Engineering and Technology, Islamabad (Pakistan)

    2014-02-25

    Highlights: • Fabrication of polycrystalline CdS thin films by Close Spaced Sublimation technique. • The direct band gap of 2.44 eV and the electrical resistivity in the order of 10{sup 6}–10{sup 8} Ω cm was measured. • Resistivity was reduced to the order of 10{sup –2}–10{sup 1} Ω m by the thermally diffusion of indium into CdS films. -- Abstract: Polycrystalline CdS thin films were deposited on glass substrates by close spaced sublimation technique. Samples of various thicknesses, ranging from 250 to 940 nm were obtained. The optical and electrical properties of pure CdS thin films were studied as a function of film thickness. The resistivity of as-deposited CdS films was in the order of 10{sup 6}–10{sup 8} Ω cm, depending upon the film thickness. In the high temperature region, carriers are transported over the grain boundaries by thermionic emission. Resistivity was reduced to the order of 10{sup −2}–10{sup 1} Ω cm by the thermally diffusion of indium into CdS films, without changing the type of carriers. The annealing temperature dependence of structural, optical and electrical properties of In-doped CdS films showed that the samples annealed at 350 °C and 400 °C exhibited better results.

  13. Thickness dependence of temperature coefficient of resistivity of polycrystalline bismuth films

    Science.gov (United States)

    Kumar, Ajay; Katyal, O. P.

    1991-04-01

    Results for the temperature coefficient of resistivity (TCR) of polycrystalline bismuth films deposited on to glass substrate are reported for the thickness range 30 300 nm. The film TCR is found to be negative for all thicknesses studied and its absolute value exhibits a maximum of 3.70×10-3 K-1 near 72.5 nm. The variation of charge carrier density with film thickness has been estimated from the presence of surface states. To include the thickness dependence of charge carrier density, a modified theory has been used to explain the observed behaviour of the TCR. The experimental results for the TCR of Bi films are found to be consistent with the theoretical values. The existence of the extremum is theoretically verified. From the analysis, the specularity parameter p is about 0.44 and the reflection coefficient R is 0.1.

  14. Measurement of material thickness in the presence of a protective film

    Science.gov (United States)

    Ramamurthy, Rajesh; Harding, Kevin

    2017-05-01

    Many sheet products from plastic to structural composites are produce in tightly controlled thickness needed for functional applications. There are many methods that have been used to measure such sheeting from mechanical rollers to optical micrometers. However, many materials are produced with a thin protective film on either side that may not have critical dimensional controls. This paper addresses the challenge of measuring sheet products to critical thickness values in the presence of protective plastic films using high speed optical gaging methods. For this application, the protective films are assumed to be transparent though not necessarily scatter free, and have thickness variations that are comparable to the tolerances of the sheet product. We will examine the pros and cons of a number of different optical measurement methods in light of resolution, speed and robustness to the film thickness variation and present an approach able to address the desired sheet measurement tolerances.

  15. Determination of Thickness of an Inaccessible Thin Film under a Multilayered System from Natural Frequencies

    Institute of Scientific and Technical Information of China (English)

    ZHOU Chang-Zhi; LI Ming-Xuan; MAO Jie; WANG Xiao-Min

    2008-01-01

    @@ We investigate the relationship between natural frequencies of a multilayered system of different elastic materials and the thickness of the undermost thin film. The natural frequencies are numerically calculated from the reflection coefficient of a sample system of "steel-epoxy resin-aluminium-thin polymer' with normal incidence.Strain energy ratio is defined and calculated to give the physics explanation why some frequencies are sensitive to thickness of the thin film in certain range. Experiments of three specimens indicate that the measured natural frequencies agree well with the theoretical ones. It is found in our experiments that the ratio of the lowest film thickness to wavelength is about 1/5. The average relative errors for the inverted polymer film thicknesses are found to be 11.8%, -4.8% and -1.3%, respectively.

  16. Effects of chromophore concentration and film thickness on thermo-optic properties of electro-optic fluorinated polyimide films

    Institute of Scientific and Technical Information of China (English)

    Hongxiang Song; Chengxun Wu

    2007-01-01

    Electro-optic (EO) effect and thermo-optic (TO) effect are jointly considered on the basis of field-induced and temperature-affected perturbations of the operating point in waveguide components. TO coefficients of EO fluorinated polyimide films with side-chain azobenzene chromophore were measured by attenuatedtotal-reflection (ATR) technique at different temperatures with TE- and TM-polarized lights, respectively.It is found that the absolute values of TO coefficients increase with the increments of both chromophore concentration and film thickness, but the polarization dependence of TO coefficients increases with the increment of chromophore concentration and decreases with the increment of film thickness.

  17. Thickness Influence on In Vitro Biocompatibility of Titanium Nitride Thin Films Synthesized by Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Liviu Duta

    2016-01-01

    Full Text Available We report a study on the biocompatibility vs. thickness in the case of titanium nitride (TiN films synthesized on 410 medical grade stainless steel substrates by pulsed laser deposition. The films were grown in a nitrogen atmosphere, and their in vitro cytotoxicity was assessed according to ISO 10993-5 [1]. Extensive physical-chemical analyses have been carried out on the deposited structures with various thicknesses in order to explain the differences in biological behavior: profilometry, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS, X-ray diffraction and surface energy measurements. XPS revealed the presence of titanium oxynitride beside TiN in amounts that vary with the film thickness. The cytocompatibility of films seems to be influenced by their TiN surface content. The thinner films seem to be more suitable for medical applications, due to the combined high values of bonding strength and superior cytocompatibility.

  18. Influence of the thickness absorbing film on the PETN ignition threshold by a laser pulse

    Directory of Open Access Journals (Sweden)

    Dolgachev Vadim A.

    2015-01-01

    Full Text Available Numerical simulation of the PETN ignition by a film, which is heated by a laser pulse was conducted. There are shown that dependence of threshold energy of ignition of PETN by a laser pulse has a linear dependence from the thicknesses of the absorbing film. Calculations shown that critical the temperature on the boundary of two materials by the end of a laser pulse with threshold density doesn’t depend from the thickness of the absorbing film. The ignition delay time of PETN by the thick film less than the ignition delay time of PETN by the thin film. The reason is that the thicker contain more heat then in the thinner one.

  19. Structural, transport and microwave properties of 123/sapphire films: Thickness effect

    Energy Technology Data Exchange (ETDEWEB)

    Predtechensky, MR.; Smal, A.N.; Varlamov, Y.D. [Institute of Thermophysics, Novosibirsk (Russian Federation)] [and others

    1994-12-31

    The effect of thickness and growth conditions on the structure and microwave properties has been investigated for the 123/sapphire films. It has been shown that in the conditions of epitaxial growth and Al atoms do not diffuse from substrate into the film and the films with thickness up to 100nm exhibit the excellent DC properties. The increase of thickness of GdBaCuO films causes the formation of extended line-mesh defects and the increase of the surface resistance (R{sub S}). The low value of surface resistance R{sub S}(75GHz,77K)=20 mOhm has been obtained for the two layer YBaCuO/CdBaCuO/sapphire films.

  20. Photometric method of determining gold film thickness of nuclear radiation silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, B.A.; Zakharchuk, D.V.; Kovalev, I.I.; Nikolaeva, T.V.; Serushkina, E.S.

    1987-07-01

    The authors examine a photometric method of assessing a nuclear radiation silicon detector's gold film thickness based on the photocurrent from a light passed through the sputtered metal layer. The surface-barrier detectors of nuclear radiations with a gold front contact are characterized by a high sensitivity to light in the 0.4-1.0 micrometer wavelength band. The relative error of determining the gold film thickness using the method examined here is of the 7% order.

  1. Investigation of thickness effects on the dielectric constant barium strontium titanate thin films

    CERN Document Server

    Grattan, L J

    2002-01-01

    The collapse in dielectric constant at small thickness commonly observed in ferroelectric thin films was measured and investigated in barium strontium titanate (Ba sub 0 sub . sub 5 Sr sub 0 sub . sub 5 TiO sub 3). The possible mechanisms responsible for this effect are reviewed. Functional measurements were performed on BST thin films, of 7.5 to 950 nm, by incorporating them into capacitor structures with bottom electrodes of strontium ruthenate (SRO) and thermally- evaporated Au top electrodes. A discussion on thin film growth considerations, optimal PLD conditions and the measurement techniques employed in the project is presented. The experimentally determined dielectric constant - thickness profile was fitted using the series capacitor model assuming low dielectric constant interfacial layers in series with the bulk. Consideration of the case where the combined 'dead layer' thickness was close to the total BST thickness revealed that, for this system, the total 'dead layer' thickness had to be less than ...

  2. Planar Zeolite Film-Based Potentiometric Gas Sensors Manufactured by a Combined Thick-Film and Electroplating Technique

    Directory of Open Access Journals (Sweden)

    Gunter Hagen

    2011-08-01

    Full Text Available Zeolites are promising materials in the field of gas sensors. In this technology-oriented paper, a planar setup for potentiometric hydrocarbon and hydrogen gas sensors using zeolites as ionic sodium conductors is presented, in which the Pt-loaded Na-ZSM-5 zeolite is applied using a thick-film technique between two interdigitated gold electrodes and one of them is selectively covered for the first time by an electroplated chromium oxide film. The influence of the sensor temperature, the type of hydrocarbons, the zeolite film thickness, and the chromium oxide film thickness is investigated. The influence of the zeolite on the sensor response is briefly discussed in the light of studies dealing with zeolites as selectivity-enhancing cover layers.

  3. Thickness Effect on Properties of Sprayed In2S3 Films for Photovoltaic Applications

    Science.gov (United States)

    Bouguila, N.; Kraini, M.; Halidou, I.; Lacaze, E.; Bouchriha, H.; Bouzouita, H.

    2016-01-01

    Indium sulfide (In2S3) films have been deposited on soda-lime glass substrates using a spray technique (CSP). Indium chloride and thiourea were used as precursors at a molar ratio of S:In = 2. The substrate temperature was fixed at 340°C. The effect of film thickness on the structural, morphological and optical properties of the as-deposited films has been studied. These films were characterized by x-ray diffraction, scanning electron microscopy (SEM), atomic force microscopy (AFM) and optical absorption spectroscopy. As-prepared samples were polycrystalline with a cubic structure and (400) as preferential orientation. Their grain size increased from 35 nm to 41 nm with increasing thickness whereas the dislocation density and microstrain of the films decreased with the increase of thickness. Both SEM and AFM images showed that the films were homogenous with an increase of the surface roughness with the increase of thickness. The optical transmittance of the films decreased from 80% to 20% in the visible and infrared regions when the thickness was increased from 0.78 μm to 6.09 μm. The optical band gap E g was found to be in the range of 2.75-2.19 eV and showed a decrease with film thickness. Based on the measured optical constants (n and k), a Wemple-Didomenico model was used to determine the values of single oscillator energy ( E 0), dispersion energy ( E d), optical band gap ( E g) and high frequency dielectric constant ( \\varepsilon_{∞} ). In addition, these films exhibited n-type conductivity and were highly resistive. These results confirm that In2S3 thin films are a promising alternative as a buffer-layer material for CuInGa(S,Se)2-based solar cells.

  4. Temperature- and thickness-dependent elastic moduli of polymer thin films

    Directory of Open Access Journals (Sweden)

    Ao Zhimin

    2011-01-01

    Full Text Available Abstract The mechanical properties of polymer ultrathin films are usually different from those of their counterparts in bulk. Understanding the effect of thickness on the mechanical properties of these films is crucial for their applications. However, it is a great challenge to measure their elastic modulus experimentally with in situ heating. In this study, a thermodynamic model for temperature- (T and thickness (h-dependent elastic moduli of polymer thin films Ef(T,h is developed with verification by the reported experimental data on polystyrene (PS thin films. For the PS thin films on a passivated substrate, Ef(T,h decreases with the decreasing film thickness, when h is less than 60 nm at ambient temperature. However, the onset thickness (h*, at which thickness Ef(T,h deviates from the bulk value, can be modulated by T. h* becomes larger at higher T because of the depression of the quenching depth, which determines the thickness of the surface layer δ.

  5. Study of lead free ferroelectrics using overlay technique on thick film microstrip ring resonator

    Directory of Open Access Journals (Sweden)

    Shridhar N. Mathad

    2016-03-01

    Full Text Available The lead free ferroelectrics, strontium barium niobates, were synthesized via the low cost solid state reaction method and their fritless thick films were fabricated by screen printing technique on alumina substrate. The X band response (complex permittivity at very high frequencies of Ag thick film microstrip ring resonator perturbed with strontium barium niobates (SrxBa1-xNb2O6 in form of bulk and thick film was measured. A new approach for determination of complex permittivity (ε′ and ε′′ in the frequency range 8–12 GHz, using perturbation of Ag thick film microstrip ring resonator (MSRR, was applied for both bulk and thick film of strontium barium niobates (SrxBa1-xNb2O6. The microwave conductivity of the bulk and thick film lie in the range from 1.779 S/cm to 2.874 S/cm and 1.364 S/cm to 2.296 S/cm, respectively. The penetration depth of microwave in strontium barium niobates is also reported.

  6. Thickness dependence of magnetic properties in La–Co substituted strontium hexaferrite films with perpendicular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Hui, Yajuan [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Cheng, Weiming, E-mail: wmcheng@mail.hust.edu.cn [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Yan, Peng [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, Jincai [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Miao, Xiangshui [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China); Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-09-15

    The thickness dependence of magnetization reversal and coercivity behavior for La–Co substituted strontium hexaferrite (Sr-M) films was investigated. It is found that perpendicular anisotropy appears only when film thickness (t) is above 110 nm. With increasing t, perpendicular anisotropy energy (K{sub u⊥}) increases gradually to its maximum of 1.76×10{sup 6} erg/cm{sup 3} at t=300 nm, but turns to decrease when t>300 nm. Moreover, when t>110 nm, those films exhibit domains pinning or Stoner–Wohlfarth reversal model, present large K{sub u⊥} values and a rapid increase in H{sub c⊥}. However, while t≤110 nm, Sr-M films show nucleation model of magnetization reversal and perform low coercivity. The origin of the coercivity varying with thickness should be correlated with the grain size and preferred orientations in Sr-M films. - Highlights: • Thickness dependence in submicro-scale bulk system is investigated for La–Sr–Co–Fe–O films. • (0 0 1) preferred orientation gradually increases until t=300 nm and then declines. • The magnetization reversal presents different models with thickness. • Perpendicular anisotropy energy increases to maximum value of 1.76×10{sup 6} erg/cm{sup 3} at t=300 nm. • The coercivity varying with thickness is correlated with the grain size and preferred orientation.

  7. Magnetic properties of permalloy films with different thicknesses deposited onto obliquely sputtered Cu underlayers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiaoyu; Sun, Xiaojun; Wang, Jianbo; Liu, Qingfang, E-mail: liuqf@lzu.edu.cn

    2015-03-01

    In this work, the influence of obliquely sputtered Cu underlayer of 10 nm on the magnetic properties of normally sputtered Permalloy thin films with different thicknesses from 10 nm to 150 nm has been investigated. It has been found that the samples with the Permalloy layer thickness ranging from 10 nm to 70 nm exhibit a good in-plane uniaxial magnetic anisotropy, and the increase of the film thickness leads to a decrease of the anisotropy field and the natural resonance frequency. The critical Permalloy layer thickness for stripe domain initiation of these films is about 80 nm, which is thinner than that of obliquely sputtered Permalloy thin films without an underlayer. The characteristic shapes of hysteresis loops which can be called ''transcritical'' are observed above the critical thickness. The condition and mechanism of appearing stripe domain structure were discussed and it has been found that the frequency response of permeability of the anisotropic films shows the characteristics of multi-peak resonance. - Highlights: • Py films were fabricated on obliquely sputtered Cu underlayers by RF magnetron sputtering. • Effects of Py layer thickness on anisotropy, ferromagnetic resonance frequency have been studied. • Samples with Py layer (<70 nm) show a good in-plane uniaxial magnetic anisotropy. • Samples with Py layer (>80 nm) show stripe domains and multi-peaks in permeability spectra.

  8. Thickness and microstructure effects in the optical and electrical properties of silver thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Guowen, E-mail: gding@intermolecular.com; Clavero, César; Schweigert, Daniel; Le, Minh [Intermolecular, Inc., 3011 North First Street, San Jose, CA 95134 (United States)

    2015-11-15

    The optical and electrical response of metal thin films approaching thicknesses in the range of the electron mean free path is highly affected by electronic scattering with the interfaces and defects. Here, we present a theoretical and experimental study on how thickness and microstructure affect the properties of Ag thin films. We are able to successfully model the electrical resistivity and IR optical response using a thickness dependent electronic scattering time. Remarkably, the product of electronic scattering time and resistivity remains constant regardless of the thickness (τx ρ = C), with a value of 59 ± 2 μΩ cm ⋅ fs for Ag films in the investigated range from 3 to 74 nm. Our findings enable us to develop a theoretically framework that allows calculating the optical response of metal thin films in the IR by using their measured thickness and resistivity. An excellent agreement is found between experimental measurements and predicted values. This study also shows the theoretical lower limit for emissivity in Ag thin films according to their microstructure and thickness. Application of the model presented here will allow rapid characterization of the IR optical response of metal thin films, with important application in a broad spectrum of fundamental and industrial applications, including optical coatings, low-emissivity windows and semiconductor industry.

  9. Thickness and microstructure effects in the optical and electrical properties of silver thin films

    Directory of Open Access Journals (Sweden)

    Guowen Ding

    2015-11-01

    Full Text Available The optical and electrical response of metal thin films approaching thicknesses in the range of the electron mean free path is highly affected by electronic scattering with the interfaces and defects. Here, we present a theoretical and experimental study on how thickness and microstructure affect the properties of Ag thin films. We are able to successfully model the electrical resistivity and IR optical response using a thickness dependent electronic scattering time. Remarkably, the product of electronic scattering time and resistivity remains constant regardless of the thickness (τx ρ = C, with a value of 59 ± 2 μΩ cm ⋅ fs for Ag films in the investigated range from 3 to 74 nm. Our findings enable us to develop a theoretically framework that allows calculating the optical response of metal thin films in the IR by using their measured thickness and resistivity. An excellent agreement is found between experimental measurements and predicted values. This study also shows the theoretical lower limit for emissivity in Ag thin films according to their microstructure and thickness. Application of the model presented here will allow rapid characterization of the IR optical response of metal thin films, with important application in a broad spectrum of fundamental and industrial applications, including optical coatings, low-emissivity windows and semiconductor industry.

  10. Hydrophobic switching nature of methylcellulose ultra-thin films: thickness and annealing effects

    Energy Technology Data Exchange (ETDEWEB)

    Innis-Samson, Vallerie Ann; Sakurai, Kenji, E-mail: sakurai@yuhgiri.nims.go.jp [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577 (Japan)

    2011-11-02

    We have studied the thermosensitive property of methylcellulose (MC) thin films supported on Si substrate by static sessile drop contact angle measurements, and their surface properties and thin film structure by x-ray reflectivity (XRR) and atomic force microscopy (AFM) techniques. From the static sessile drop contact angle measurements, the MC thin films showed the characteristic hydrophilic-to-hydrophobic transition at {approx}70 {sup 0}C, which is the lower critical solution temperature of the bulk solution volume phase separation transition. For films with thickness d {<=} R{sub g}, the onset of such a transition is affected by the film thickness while very thick films, d >> R{sub g}, yielded higher contact angles. Annealing the MC thin films with thicknesses {approx}200 A (near the radius of gyration, R{sub g}, of the polymer) below the bulk glass transition temperature (T{sub g} {approx} 195 deg. C) would not change the hydrophobic switch nature of the film but annealing 'at' and above the bulk T{sub g} would change its surface property. From surface topography images by AFM, there were no significant changes in either the roughness or the film texture before and after annealing. With XRR data, we were able to determine that such changes in the surface properties are highly correlated to the film thickness changes after the annealing process. This study, we believe, is the first to examine the thermal annealing affects on the thermal response function of a thermoresponsive polymer and is important for researching how to tailor the hydrophobic switching property of MC thin films for future sensing applications. (paper)

  11. Hydrophobic switching nature of methylcellulose ultra-thin films: thickness and annealing effects.

    Science.gov (United States)

    Innis-Samson, Vallerie Ann; Sakurai, Kenji

    2011-11-02

    We have studied the thermosensitive property of methylcellulose (MC) thin films supported on Si substrate by static sessile drop contact angle measurements, and their surface properties and thin film structure by x-ray reflectivity (XRR) and atomic force microscopy (AFM) techniques. From the static sessile drop contact angle measurements, the MC thin films showed the characteristic hydrophilic-to-hydrophobic transition at ∼70 °C, which is the lower critical solution temperature of the bulk solution volume phase separation transition. For films with thickness d ≤ R(g), the onset of such a transition is affected by the film thickness while very thick films, d ≫ R(g), yielded higher contact angles. Annealing the MC thin films with thicknesses ∼200 Å (near the radius of gyration, R(g), of the polymer) below the bulk glass transition temperature (T(g) ∼ 195 ° C) would not change the hydrophobic switch nature of the film but annealing 'at' and above the bulk T(g) would change its surface property. From surface topography images by AFM, there were no significant changes in either the roughness or the film texture before and after annealing. With XRR data, we were able to determine that such changes in the surface properties are highly correlated to the film thickness changes after the annealing process. This study, we believe, is the first to examine the thermal annealing affects on the thermal response function of a thermoresponsive polymer and is important for researching how to tailor the hydrophobic switching property of MC thin films for future sensing applications.

  12. Hydrophobic switching nature of methylcellulose ultra-thin films: thickness and annealing effects

    Science.gov (United States)

    Innis-Samson, Vallerie Ann; Sakurai, Kenji

    2011-11-01

    We have studied the thermosensitive property of methylcellulose (MC) thin films supported on Si substrate by static sessile drop contact angle measurements, and their surface properties and thin film structure by x-ray reflectivity (XRR) and atomic force microscopy (AFM) techniques. From the static sessile drop contact angle measurements, the MC thin films showed the characteristic hydrophilic-to-hydrophobic transition at ˜70 °C, which is the lower critical solution temperature of the bulk solution volume phase separation transition. For films with thickness d ≤ Rg, the onset of such a transition is affected by the film thickness while very thick films, d ≫ Rg, yielded higher contact angles. Annealing the MC thin films with thicknesses ˜200 Å (near the radius of gyration, Rg, of the polymer) below the bulk glass transition temperature (Tg ˜ 195 ° C) would not change the hydrophobic switch nature of the film but annealing ‘at’ and above the bulk Tg would change its surface property. From surface topography images by AFM, there were no significant changes in either the roughness or the film texture before and after annealing. With XRR data, we were able to determine that such changes in the surface properties are highly correlated to the film thickness changes after the annealing process. This study, we believe, is the first to examine the thermal annealing affects on the thermal response function of a thermoresponsive polymer and is important for researching how to tailor the hydrophobic switching property of MC thin films for future sensing applications.

  13. Quantifying Local Thickness and Composition in Thin Films of Organic Photovoltaic Blends by Raman Scattering

    KAUST Repository

    Rodríguez-Martínez, Xabier

    2017-07-06

    We report a methodology based on Raman spectroscopy that enables the non-invasive and fast quantitative determination of local thickness and composition in thin films (from few monolayers to hundreds of nm) of one or more components. We apply our methodology to blends of organic conjugated materials relevant in the field of organic photovoltaics. As a first step, we exploit the transfer-matrix formalism to describe the Raman process in thin films including reabsorption and interference effects of the incoming and scattered electric fields. This allows determining the effective solid-state Raman cross-section of each material by studying the dependence of the Raman intensity on film thickness. These effective cross sections are then used to estimate the local thickness and composition in a series of polymer:fullerene blends. We find that the model is accurate within ±10 nm in thickness and ±5 vol% in composition provided that (i) the film thickness is kept below the thickness corresponding to the first maximum of the calculated Raman intensity oscillation; (ii) the materials making up the blend show close enough effective Raman cross-sections; and (iii) the degree of order attained by the conjugated polymer in the blend is similar to that achieved when cast alone. Our methodology opens the possibility to make quantitative maps of composition and thickness over large areas (from microns to centimetres squared) with diffraction-limited resolution and in any multi-component system based thin film technology.

  14. Gas sensing properties of Cu and Cr activated BST thick films

    Indian Academy of Sciences (India)

    G H Jain; L A Patil

    2006-08-01

    H2S gas sensing properties of BST ((Ba0.67Sr0.33)TiO3) thick films are reported here for the first time. BST ceramic powder was prepared by mechanochemical process. Thick films of BST were prepared by screen-printing technique. The sensing performance of the films was tested for various gases. The films were surface customized by dipping them into aqueous solutions of CuCl2 and CrO3 for various intervals of time. These surface modified BST films showed improved sensitivity to H2S gas (100 ppm) than pure BST film. Chromium oxide was observed to be a better activator than copper oxide in H2S gas sensing. The effect of microstructure and amount of activators on H2S gas sensing were discussed. The sensitivity, selectivity, stability, response and recovery time of the sensor were measured and presented.

  15. Angular multiplexing holograms of four images recorded on photopolymer films with recording-film-thickness-dependent holographic characteristics

    Science.gov (United States)

    Osabe, Keiichi; Kawai, Kotaro

    2017-03-01

    In this study, angular multiplexing hologram recording photopolymer films were studied experimentally. The films contained acrylamide as a monomer, eosin Y as a sensitizer, and triethanolamine as a promoter in a polyvinyl alcohol matrix. In order to determine the appropriate thickness of the photopolymer films for angular multiplexing, photopolymer films with thicknesses of 29-503 μm were exposed to two intersecting beams of a YVO laser at a wavelength of 532 nm to form a holographic grating with a spatial frequency of 653 line/mm. The diffraction efficiencies as a function of the incident angle of reconstruction were measured. A narrow angular bandwidth and high diffraction efficiency are required for angular multiplexing; hence, we define the Q value, which is the diffraction efficiency divided by half the bandwidth. The Q value of the films depended on the thickness of the films, and was calculated based on the measured diffraction efficiencies. The Q value of a 297-μm-thick film was the highest of the all films. Therefore, the angular multiplexing experiments were conducted using 300-μm-thick films. In the angular multiplexing experiments, the object beam transmitted by a square aperture was focused by a Fourier transform lens and interfered with a reference beam. The maximum order of angular multiplexing was four. The signal intensity that corresponds to the squared-aperture transmission and the noise intensity that corresponds to transmission without the square aperture were measured. The signal intensities decreased as the order of angular multiplexing increased, and the noise intensities were not dependent on the order of angular multiplexing.

  16. Investigation of Top/bottom Electrode and Diffusion Barrier Layer for PZT thick film MEMS Sensors

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Hindrichsen, Christian Carstensen; Lou-Møller, R.

    2007-01-01

    In this work screen printed piezoelectric Ferroperm PZ26 lead zirconate titanate (PZT) thick film is used for two MEMS devices. A test structure is used to investigate several aspects regarding bottom and top electrodes. 450 nm ZrO2 thin film is found to be an insufficient diffusion barrier layer...

  17. Effect of heat and film thickness on a photoinduced phase transition in azobenzene liquid crystalline polyesters

    DEFF Research Database (Denmark)

    Sanchez, C; Alcala, R; Hvilsted, Søren

    2003-01-01

    The liquid crystal to isotropic phase transition induced with 488 nm light in films of liquid crystalline azobenzene polyesters has been studied as a function of temperature, light intensity, and film thickness. That phase transition is associated with the photoinduced trans-cis-trans isomerizati...

  18. Plasmonic extinction in gold nanoparticle-polymer films as film thickness and nanoparticle separation decrease below resonant wavelength

    Science.gov (United States)

    Dunklin, Jeremy R.; Bodinger, Carter; Forcherio, Gregory T.; Keith Roper, D.

    2017-01-01

    Plasmonic nanoparticles embedded in polymer films enhance optoelectronic properties of photovoltaics, sensors, and interconnects. This work examined optical extinction of polymer films containing randomly dispersed gold nanoparticles (AuNP) with negligible Rayleigh scattering cross-sections at particle separations and film thicknesses less than (sub-) to greater than (super-) the localized surface plasmon resonant (LSPR) wavelength, λLSPR. Optical extinction followed opposite trends in sub- and superwavelength films on a per nanoparticle basis. In ˜70-nm-thick polyvinylpyrrolidone films containing 16 nm AuNP, measured resonant extinction per particle decreased as particle separation decreased from ˜130 to 76 nm, consistent with trends from Maxwell Garnett effective medium theory and coupled dipole approximation. In ˜1-mm-thick polydimethylsiloxane films containing 16-nm AuNP, resonant extinction per particle plateaued at particle separations ≥λLSPR, then increased as particle separation radius decreased from ˜514 to 408 nm. Contributions from isolated particles, interparticle interactions and heterogeneities in sub- and super-λLSPR films containing AuNP at sub-λLSPR separations were examined. Characterizing optoplasmonics of thin polymer films embedded with plasmonic NP supports rational development of optoelectronic, biomedical, and catalytic activity using these nanocomposites.

  19. Monitoring of Spectral Map Changes from Normal State to Superconducting State in High-TC Superconductor Films Using Raman Imaging

    Directory of Open Access Journals (Sweden)

    J. L. González-Solís

    2015-01-01

    Full Text Available We have explored the chemical structure of TlBa2Ca2Cu3O9 high-TC superconductor films with Tl-1223 phase to monitor spectral map changes from normal state to superconducting state using the technique of Raman imaging. Raman images were performed for 12 different temperatures in the 77–293 K range. At room temperature, the Raman images were characterized by a single color but as the temperature dropped a new color appeared and when the temperature of 77 K is reached and the superconducting state is assured, the Raman images were characterized by the red, green, and blue colors. Our study could suggest that the superconducting state emerged around 133 K, in full agreement with those reported in the literature. A cross-checking was done applying principal component analysis (PCA to other sets of Raman spectra of our films measured at different temperatures. PCA result showed that the spectra can be grouped into two temperature ranges, one in the 293–153 K range and the other in the 133–77 K range suggesting that transition to the superconducting state occurred at some temperature around 133 K. This is the first report of preliminary results evaluating the usefulness of Raman imaging in determination of transition temperature of superconductor films.

  20. The Effects of Two Thick Film Deposition Methods on Tin Dioxide Gas Sensor Performance

    OpenAIRE

    Bakrania, Smitesh D.; Margaret S. Wooldridge

    2009-01-01

    This work demonstrates the variability in performance between SnO2 thick film gas sensors prepared using two types of film deposition methods. SnO2 powders were deposited on sensor platforms with and without the use of binders. Three commonly utilized binder recipes were investigated, and a new binder-less deposition procedure was developed and characterized. The binder recipes yielded sensors with poor film uniformity and poor structural integrity, compared to the binder-less deposition meth...

  1. The Influence of Electrical Pulses on Thick Film (Du Pont 1421 Birox) Resistors

    OpenAIRE

    Tancula, M.; Kozlowski, J. M.

    1982-01-01

    This paper presents data on the effect of electric pulses on thick film resistors made using Du Pont 1421 Birox resistor pastes.Resistance changes during the application of the electric pulses were investigated. Two types of change were observed: reversible and irreversible (i.e. catastrophic).In order to illustrate the causes of these changes, observations of the film on a scanning electron microscope were made. Microcracks were observed in the film, which were mostly responsible for the per...

  2. Thickness dependency of sol-gel derived ZnO thin films on gas sensing behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Kakati, Nitul; Jee, Seung Hyun; Kim, Su Hyun; Oh, Jun Young; Yoon, Young Soo, E-mail: yoonys@yonsei.ac.k

    2010-10-29

    ZnO thin films were fabricated by a sol-gel method using Zn(CH{sub 3}COO){sub 2}.2H{sub 2}O as starting material in order to prepare an acetone gas sensor. A homogeneous and stable solution was prepared by dissolving the zinc acetate in a solution of ethanol and monoethanolamine. The sol-gel solution is coated on alumina substrates with various thicknesses by spin coating technique and heat treated to grow crystalline ZnO thin films. The effect of thickness on physical and electrical properties of as deposited ZnO thin films has been studied. The as deposited ZnO thin films were characterized by X-ray diffraction spectroscopy, field emission scanning electron microscopy and atomic force microscopy. The root mean square surface roughness factors increase with thickness of the films and found 3.9, 6.6, 9.0, and 11.28 nm for 80-, 220-, 450- and 620-nm-thin films respectively. The activation energies of the films are calculated from the resistance temperature characteristics. The sensitivities of the ZnO films towards the acetone gas were determined at an operating temperature of 200 {sup o}C. The sensitivity towards acetone vapor is strongly depending on surface morphology of the ZnO thin films.

  3. Spacer Thickness-Dependent Electron Transport Performance of Titanium Dioxide Thick Film for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Reda E. El-Shater

    2015-01-01

    Full Text Available A titanium dioxide (P25 film was deposited by cast coating as conductive photoelectrode and subsequently immersed in dye solution (N719 to fabricate the photoanode of dye-sensitized solar cells (DSSCs. A plastic spacer was used as a separation and sealant layer between the photoanode and the counter electrode. The effect of the thickness of this spacer on the transfer of electrons in the liquid electrolyte of the DSSCs was studied by means of both IV curves and electrochemical impedance. Using a spacer thickness range of 20 μm to 50 μm, efficiency ranges from 3.73% to 7.22%. The highest efficiency of 7.22% was obtained with an optimal spacer thickness of 40 μm.

  4. Terahertz paintmeter for noncontact monitoring of thickness and drying progress in paint film

    Science.gov (United States)

    Yasui, Takeshi; Yasuda, Takashi; Sawanaka, Ken-Ichi; Araki, Tsutomu

    2005-11-01

    We propose a paintmeter for noncontact and remote monitoring of the thickness and drying progress of a paint film based on the time-of-flight measurement of the echo signal of a terahertz (THz) electromagnetic pulse. The proposed method is effectively applied to two-dimensional mapping of the painting thickness distribution for single-layer and multilayer paint films. Furthermore, adequate parameters for the drying progress are extracted from the THz pulse-echo signal and effectively applied to monitor the wet-to-dry transformation. The THz paintmeter can be a powerful tool for quality control of the paint film on the in-process monitoring of car body painting.

  5. Resistive switching in a few nanometers thick tantalum oxide film formed by a metal oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, Takeo, E-mail: t-ohno@wpi-aimr.tohoku.ac.jp [WPI - Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Japan Science and Technology Agency (JST), PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Samukawa, Seiji, E-mail: samukawa@ifs.tohoku.ac.jp [WPI - Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Institute of Fluid Science (IFS), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

    2015-04-27

    Resistive switching in a Cu/Ta{sub 2}O{sub 5}/Pt structure that consisted of a few nanometer-thick Ta{sub 2}O{sub 5} film was demonstrated. The Ta{sub 2}O{sub 5} film with thicknesses of 2–5 nm was formed with a combination of Ta metal film deposition and neutral oxygen particle irradiation at room temperature. The device exhibited a bipolar resistive switching with a threshold voltage of 0.2 V and multilevel switching operation.

  6. Fine uniform filament superconductors

    Science.gov (United States)

    Riley, Jr., Gilbert N.; Li, Qi; Roberts, Peter R.; Antaya, Peter D.; Seuntjens, Jeffrey M.; Hancock, Steven; DeMoranville, Kenneth L.; Christopherson, Craig J.; Garrant, Jennifer H.; Craven, Christopher A.

    2002-01-01

    A multifilamentary superconductor composite having a high fill factor is formed from a plurality of stacked monofilament precursor elements, each of which includes a low density superconductor precursor monofilament. The precursor elements all have substantially the same dimensions and characteristics, and are stacked in a rectilinear configuration and consolidated to provide a multifilamentary precursor composite. The composite is thereafter thermomechanically processed to provide a superconductor composite in which each monofilament is less than about 50 microns thick.

  7. Optimizing diode thickness for thin-film solid state thermal neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, John W.; Mejia, Israel; Quevedo-Lopez, Manuel A.; Gnade, Bruce [Department of Materials and Science, University of Texas at Dallas, Richardson, Texas 75080 (United States); Kunnen, George R.; Allee, David [Flexible Display Center at Arizona State University, Tempe, Arizona 85284 (United States)

    2012-10-01

    In this work, we investigate the optimal thickness of a semiconductor diode for thin-film solid state thermal neutron detectors. We evaluate several diode materials, Si, CdTe, GaAs, C (diamond), and ZnO, and two neutron converter materials, {sup 10}B and {sup 6}LiF. Investigating a coplanar diode/converter geometry, we determine the minimum semiconductor thickness needed to achieve maximum neutron detection efficiency. By keeping the semiconductor thickness to a minimum, gamma rejection is kept as high as possible. In this way, we optimize detector performance for different thin-film semiconductor materials.

  8. Ceramic thick film humidity sensor based on MgTiO{sub 3} + LiF

    Energy Technology Data Exchange (ETDEWEB)

    Kassas, Ahmad, E-mail: a.kassas.mcema@ul.edu.lb [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon); Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), 50130 Cherbourg-Octeville (France); Bernard, Jérôme; Lelièvre, Céline; Besq, Anthony; Guhel, Yannick; Houivet, David; Boudart, Bertrand [Laboratoire Universitaire des Sciences Appliquées de Cherbourg (LUSAC), 50130 Cherbourg-Octeville (France); Lakiss, Hassan [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon); Faculty of Engineering, Section III, Hariri Campus, Hadath, Beirut (Lebanon); Hamieh, Tayssir [Faculty of Agricultural Engineering and Veterinary Medicine, Laboratory of Materials, Catalysis, Environment and Analytical Methods (MCEMA), Faculty of Sciences and Doctoral School of Sciences and Technology (EDST), Lebanese University, Hariri Campus, Hadath, Beirut (Lebanon)

    2013-10-15

    Graphical abstract: - Highlights: • The fabricated sensor based on MgTiO{sub 3} + LiF materials used the spin coating technology. • The response time is 70 s to detect variation between 5 and 95% relative humidity. • The addition of Scleroglucan controls the viscosity and decreases the roughness of thick film surface. • This humidity sensor is a promising, low-cost, high-quality, reliable ceramic films, that is highly sensitive to humidity. - Abstract: The feasibility of humidity sensor, consisting of a thick layer of MgTiO{sub 3}/LiF materials on alumina substrate, was studied. The thermal analysis TGA-DTGA and dilatometric analysis worked out to confirm the sintering temperature. An experimental plan was applied to describe the effects of different parameters in the development of the thick film sensor. Structural and microstructural characterizations of the developed thick film were made. Rheological study with different amounts of a thickener (scleroglucan “sclg”), showing the behavior variation, as a function of sclg weight % was illustrated and rapprochement with the results of thickness variation as a function of angular velocity applied in the spin coater. The electrical and dielectric measurements confirmed the sensitivity of the elaborated thick film against moisture, along with low response time.

  9. Investigation of magnetic properties in thick CoFeB alloy films for controllable anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ke; Huang, Ya; Chen, Ruofei; Xu, Zhan [Huaqiao University, College of Information Science and Engineering, Xiamen City (China)

    2016-02-15

    CoFeB alloy material has attracted interest for its wide uses in magnetic memory devices and sensors. We investigate magnetic properties of thick Co{sub 40}Fe{sub 40}B{sub 20} films in the thickness range from 10 to 100 nm sandwiched by MgO and Ta layers. Strong in-plane uniaxial magnetic anisotropy is revealed in the as-deposited amorphous films by angular dependent magnetic measurements, and the growth-induced anisotropy is found to strongly depend on the film thickness. A fourfold cubic magnetic anisotropy develops with annealing, as a result of improved crystalline structure in films confirmed by X-ray diffraction measurements. The observed magnetic properties can be explained by the superposition of the uniaxial and additional cubic magnetic anisotropy, tuned by annealing temperature. (orig.)

  10. Investigation of magnetic properties in thick CoFeB alloy films for controllable anisotropy

    Science.gov (United States)

    Wang, Ke; Huang, Ya; Chen, Ruofei; Xu, Zhan

    2016-02-01

    CoFeB alloy material has attracted interest for its wide uses in magnetic memory devices and sensors. We investigate magnetic properties of thick Co40Fe40B20 films in the thickness range from 10 to 100 nm sandwiched by MgO and Ta layers. Strong in-plane uniaxial magnetic anisotropy is revealed in the as-deposited amorphous films by angular dependent magnetic measurements, and the growth-induced anisotropy is found to strongly depend on the film thickness. A fourfold cubic magnetic anisotropy develops with annealing, as a result of improved crystalline structure in films confirmed by X-ray diffraction measurements. The observed magnetic properties can be explained by the superposition of the uniaxial and additional cubic magnetic anisotropy, tuned by annealing temperature.

  11. Electromechanical Properties of Microcantilever Actuated by Enhanced Piezoelectric PZT Thick Film

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-Mei; ZHAO Quan-Liang; CAO Mao-Sheng; YUAN Jie; DUAN Zhong-Xia; QIU Cheng-Jun

    2008-01-01

    Pb(Zro.53,Tio.47)O3 (PZT) films with thicknesses of 0.8μm, 2μm and 4μm are prepared by a sol-gel method and their longitudinal piezoelectric coefficients are analysed. The results show that the PZT thick films, whose density is closer to bulk PZT, has the better crystallization, with d33 and density much larger than those of PZT thin films. A piezoelectric microcantilever actuated by a 4-μm-thick PZT film is fabricated and its displacement is measured in different frequencies and voltages. The displacement increases linearly with the increasing bias,and the maximum displacement of 0.544 μm is observed at 30kHz for 5V bias. The resonant frequency obtained in the experiment matches quite well with the theoretical result, and it is shown that the resonant frequency of PZT microcantilever could be controlled and predicated.

  12. Lift-off PMN-PT Thick Film for High Frequency Ultrasonic Biomicroscopy.

    Science.gov (United States)

    Zhu, Benpeng; Han, Jiangxue; Shi, Jing; Shung, K Krik; Wei, Q; Huang, Yuhong; Kosec, M; Zhou, Qifa

    2010-10-01

    Piezoelectric 0.65Pb(Mg(1/3)Nb(2/3))O(3)-0.35PbTiO(3) (PMN-35PT) thick film with a thickness of approximately 12 µm has been deposited on the platinum buffered Si substrate via a sol-gel composite method. The separation of the film from the substrate was achieved using a wet chemical method. The lifted-off PMN-35PT thick film exhibited good dielectric and ferroelectric properties. At 1 kHz, the dielectric constant and the dielectric loss were 3,326 and 0.037, respectively, while the remnant polarization was 30.0 µC/cm(2). A high frequency single element acoustic transducer fabricated with this film showed a bandwidth at -6 dB of 63.6% at 110 MHz.

  13. Influence of Thickness on Field Emission Characteristics of Nanometre Boron Nitride Thin Films

    Institute of Scientific and Technical Information of China (English)

    顾广瑞; 李英爱; 陶艳春; 何志; 李俊杰; 殷红; 李卫青; 赵永年

    2003-01-01

    Nanometre boron nitride (BN) thin films with various thickness (54-135 nm) were prepared on Si(100) by rf magnetic sputtering physical vapour deposition. The field emission characteristics of the BN thin films were measured in an ultrahigh vacuum system. A threshold electric field of 11 V/μm and the highest emission current density of 240 μA/cm2 at an electric field of 23 V/μm were obtained for the about 54-nm-thick BN film. The threshold electric field increases with increasing the thickness in the nanometre range. The Fowler-Nordheim plots show that electrons were emitted from BN to vacuum by tunnelling through the potential barrier at the surface of BN thin films.

  14. Self-Poling of BiFeO3 Thick Films.

    Science.gov (United States)

    Khomyakova, Evgeniya; Sadl, Matej; Ursic, Hana; Daniels, John; Malic, Barbara; Bencan, Andreja; Damjanovic, Dragan; Rojac, Tadej

    2016-08-01

    Bismuth ferrite (BiFeO3) is difficult to pole because of the combination of its high coercive field and high electrical conductivity. This problem is particularly pronounced in thick films. The poling, however, must be performed to achieve a large macroscopic piezoelectric response. This study presents evidence of a prominent and reproducible self-poling effect in few-tens-of-micrometer-thick BiFeO3 films. Direct and converse piezoelectric measurements confirmed that the as-sintered BiFeO3 thick films yield d33 values of up to ∼20 pC/N. It was observed that a significant self-poling effect only appears in cases when the films are heated and cooled through the ferroelectric-paraelectric phase transition (Curie temperature TC ∼ 820 °C). These self-poled films exhibit a microstructure with randomly oriented columnar grains. The presence of a compressive strain gradient across the film thickness cooled from above the TC was experimentally confirmed and is suggested to be responsible for the self-poling effect. Finally, the macroscopic d33 response of the self-poled BiFeO3 film was characterized as a function of the driving-field frequency and amplitude.

  15. Microstructure parameters and optical properties of cadmium ferrite thin films of variable thickness

    Science.gov (United States)

    Shaaban, E. R.

    2014-06-01

    CdFe2O4 thin films of different thicknesses were deposited onto glass substrates by the thermal evaporation technique. Their structural characteristics were studied by X-ray diffraction (XRD). The microstructure parameters, crystallite size, and microstrain were calculated. It is observed that both the crystallite size increases and microstrain increase with increasing with the film thickness. The fundamental optical parameters like absorption coefficient and optical band gap are calculated in the strong absorption region of transmittance and reflectance spectrum. The refractive indices have been evaluated in terms of the envelope method, which has been suggested by Swanepoel in the transparent region. The refractive index can be extrapolated by the Cauchy dispersion relationship over the whole spectra range, which extended from 400 to 2500 nm. The refractive index, n, increases on increasing the film thickness up to 733 nm and the variation of n with higher thickness lies within the experimental errors.

  16. Effect of withdrawal speed on film thickness and hexagonal pore-array dimensions of SBA-15 mesoporous silica thin film.

    Science.gov (United States)

    Hwang, Junho; Shoji, Naoko; Endo, Akira; Daiguji, Hirofumi

    2014-12-30

    Two-dimensional hexagonal mesoporous silica thin films of SBA-15 were synthesized on Si substrates via dip-coating using an evaporation-induced self-assembly process. The effect of the withdrawal speed on the thicknesses, one-dimensional pore alignments, and two-dimensional hexagonal pore arrays of the films was elucidated. Detailed analyses of FE-SEM and TEM images and XRD and XRR patterns of the synthesized thin films clarified that the pore sizes, interplanar spacings, and film thicknesses depend on the withdrawal speed. Furthermore, the same films were synthesized on Si substrates with microtrenches. The local flow of coating solutions around microtrenches affects the pore direction as well as the film thickness. In order to form well-ordered mesoporous silica thin films with large surface areas, it is important to control the synthetic conditions such as the local flow of the coating solutions as well as the physicochemical properties of the silica precursor solutions or template molecules.

  17. Fabrication and Characterization of PZT Thick Films for Sensing and Actuation

    Directory of Open Access Journals (Sweden)

    Kuo-Ching Kuo

    2007-04-01

    Full Text Available Lead Zirconate Titanate oxide (PZT thick films with thicknesses of up to 10 μmwere developed using a modified sol-gel technique. Usually, the film thickness is less than1 μm by conventional sol-gel processing, while the electrical charge accumulation whichreveals the direct effect of piezoelectricity is proportional to the film thickness and thereforerestricted. Two approaches were adopted to conventional sol-gel processing – precursorconcentration modulation and rapid thermal annealing. A 10 μm thick film was successfullyfabricated by coating 16 times via this technique. The thickness of each coating layer wasabout 0.6 μm and the morphology of the film was dense with a crack-free area as large as 16mm2. In addition, the structure, surface morphology and physical properties werecharacterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and atomicforce microscopy (AFM and electrical performance. The dielectric constant and hysteresisloops were measured as electric characteristics. This study investigates the actuation andsensing performance of the vibrating structures with the piezoelectric thick film. Theactuation tests demonstrated that a 4 mm x 4 mm x 6.5 μm PZT film drove a 40 mm x 7 mmx 0.5 mm silicon beam as an actuator. Additionally, it generated an electrical signal of 60mVpp as a sensor, while vibration was input by a shaker. The frequencies of the first twomodes of the beam were compared with the theoretical values obtained by Euler-Bernoullibeam theory. The linearity of the actuation and sensing tests were also examined.

  18. An estimation method on failure stress of micro thickness Cu film-substrate structure

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The failure of thin film-substrate structure occurs mainly at the thin film or the interface. However, the characterizing and estimating methods of failure stress in thin film are neither uniform nor effective because there are some complex effects of such as size, interface and stress state on the failure behavior of thin film-substrate structure. Based on the scanning electron microscope (SEM) in-situ in- vestigation on the failure models of the Cu thin film-substrate structure and the nano scratched testing results, the failure stresses in different thicknesses of the Cu film-substrate were characterized, which were compared and confirmed by other methods, such as Stoney formula and other empiric equations. These results indicate that the novel estimating method of failure stress in thin film based on the critical wavelength of surface unstable analysis is better than other methods. The main reason is that the novel estimating method of failure stress in meso thickness film fully considered the effect factors of free surface unstable behavior and elastic anisotropy of thin film. Therefore, the novel estimating method of failure stress assists people to understand the critical interfacial strength and to set up the failure criterion of thin film-substrate structure.

  19. An estimation method on failure stress of micro thickness Cu film-substrate structure

    Institute of Scientific and Technical Information of China (English)

    WANG XiShu; LI Ying; MENG XiangKang

    2009-01-01

    The failure of thin film-substrate structure occurs mainly at the thin film or the interface.However,the characterizing and estimating methods of failure stress in thin film are neither uniform nor effective because there are some complex effects of such as size,interface and stress state on the failure behavior of thin film-substrate structure.Based on the scanning electron microscope(SEM)in-situ investigation on the failure models of the Cu thin film-substrata structure and the nano scratched testing results,the failure stresses in different thicknesses of the Cu film-substrate were characterized,which were compared and confirmed by other methods,such as Stoney formula and other empiric equations.These results indicate that the novel estimating method of failure stress in thin film based on the critical wavelength of surface unstable analysis is better than other methods.The main reason is that the novel estimating method of failure stress in meso thickness film fully considered the effect factors of free surface unstable behavior and elastic anisotropy of thin film.Therefore,the novel estimating method of failure stress assists people to understand the critical interracial strength and to set up the failure criterion of thin film-substrate structure.

  20. Surface functionalization by fine ultraviolet-patterning of nanometer-thick liquid lubricant films

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Renguo [Department of Complex Systems Science, Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Zhang, Hedong, E-mail: zhang@is.nagoya-u.ac.jp [Department of Complex Systems Science, Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Komada, Suguru [Department of Micro-Nano System Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Mitsuya, Yasunaga [Nagoya Industrial Science Research Institute, Noa Yotsuya Building 2F, 1-13, Yotsuya-Douri, Chikusa-ku, Nagoya 464-0819 (Japan); Fukuzawa, Kenji; Itoh, Shintaro [Department of Micro-Nano System Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2014-11-30

    Highlights: • We present fine UV-patterning of nm-thick liquid films for surface functionalization. • The patterned films exhibit both a morphological pattern and a functional pattern of different surface properties. • The finest pattern linewidth was 0.5 μm. • Fine patterning is crucial for improving surface and tribological properties. - Abstract: For micro/nanoscale devices, surface functionalization is essential to achieve function and performance superior to those that originate from the inherent bulk material properties. As a method of surface functionalization, we dip-coated nanometer-thick liquid lubricant films onto solid surfaces and then patterned the lubricant films with ultraviolet (UV) irradiation through a photomask. Surface topography, adhesion, and friction measurements demonstrated that the patterned films feature a concave–convex thickness distribution with thicker lubricant in the irradiated regions and a functional distribution with lower adhesion and friction in the irradiated convex regions. The pattern linewidth ranged from 100 to as fine as 0.5 μm. The surface functionalization effect of UV-patterning was investigated by measuring the water contact angles, surface energies, friction forces, and depletion of the patterned, as-dipped, and full UV-irradiated lubricant films. The full UV-irradiated lubricant film was hydrophobic with a water contact angle of 102.1°, and had lower surface energy, friction, and depletion than the as-dipped film, which was hydrophilic with a water contact angle of 80.7°. This demonstrates that UV irradiation substantially improves the surface and tribological properties of the nanometer-thick liquid lubricant films. The UV-patterned lubricant films exhibited superior surface and tribological properties than the as-dipped film. The water contact angle increased and the surface energy, friction, and depletion decreased as the pattern linewidth decreased. In particular, the 0.5-μm patterned lubricant

  1. Equivalent-Circuit Model for the Thickness-Shear Mode Resonator with a Viscoelastic Film Near Film Resonance

    Energy Technology Data Exchange (ETDEWEB)

    BANDEY, HELEN L.; BROWN, MARK J.; CERNOSEK, RICHARD W.; HILLMAN, A. ROBERT; MARTIN, STEPHEN J.

    1999-09-16

    We derive a lumped-element, equivalent-circuit model for the thickness shear mode (TSM) resonator with a viscoelastic film. This modified Butterworth-Van Dyke model includes in the motional branch a series LCR resonator, representing the quartz resonance, and a parallel LCR resonator, representing the film resonance. This model is valid in the vicinity of film resonance, which occurs when the acoustic phase shift across the film is an odd multiple of {pi}/2 radians. This model predicts accurately the frequency changes and damping that arise at resonance and is a reasonable approximation away from resonance. The elements of the model are explicitly related to film properties and can be interpreted in terms of elastic energy storage and viscous power dissipation. The model leads to a simple graphical interpretation of the coupling between the quartz and film resonances and facilitates understanding of the resulting responses. These responses are compared with predictions from the transmission-line and the Sauerbrey models.

  2. Impact of film thickness on the morphology of mesoporous carbon films using organic-organic self-assembly.

    Science.gov (United States)

    Vogt, Bryan D; Chavez, Vicki L; Dai, Mingzhi; Arreola, M Regina Croda; Song, Lingyan; Feng, Dan; Zhao, Dongyuan; Perera, Ginusha M; Stein, Gila E

    2011-05-03

    Mesoporous polymer and carbon thin films are prepared by the organic-organic self-assembly of an oligomeric phenolic resin with an amphiphilic triblock copolymer template, Pluronic F127. The ratio of resin to template is selected such that a body-centered cubic (Im3m) mesostructure is formed in the bulk. However, well-ordered mesoporous films are not always obtained for thin films (body-centered cubic symmetry with a preferential orientation of the closest-packed (110) plane parallel to the substrate. Film thickness and initial composition of the carbonizable precursors in the template are critical factors in determining the morphology of mesoporous carbon films. These results provide insight into why difficulties have been reported in producing ultrathin ordered mesoporous carbon films using cooperative organic-organic self-assembly.

  3. Humidity sensing properties of WO{sub 3} thick film resistor prepared by screen printing technique

    Energy Technology Data Exchange (ETDEWEB)

    Garde, Arun S, E-mail: arungarde@yahoo.co.in

    2014-12-25

    Highlights: • Polycrystalline WO{sub 3} Thick films are fabricated by screen printing technique. • Monoclinic phases were the majority in formation of films. • The peak at 1643 cm{sup −1} shows stretching vibrations attributed to W-OH of adsorbed H{sub 2}O. • Absorption peaks in the range 879–650 cm{sup −1} are attributed to the stretching W-O-W bonds. • Increase in resistance with decrease in RH when exposed to 20–100% RH. - Abstract: Thick films of tungsten oxide based were prepared using standard screen printing technique. To study the effect of temperature on the thick films were fired at different temperature for 30 min in air atmosphere. The WO{sub 3} thick films were characterized with X-ray diffraction, scanning electron microscopy and EDAX for elemental analysis. The formation of mixed phases of the film together with majority of monoclinic phase was observed. IR spectra confirm the peak at 1643 cm{sup −1} clearly shows stretching vibrations attributed to the W-OH bending vibration mode of the adsorbed water molecules. The absorption peaks in the range 879–650 cm{sup −1} are attributed to the stretching W-O-W bonds (i.e. ν [W-O{sub inter}-W]). The peak located at 983 cm{sup −1} belong to W=O terminal of cluster boundaries. A change in the resistance was observed with respect to the relative humidity when the WO{sub 3} thick films were exposed to a wide humidity range of 20–100%. An increasing firing temperature of WO{sub 3} film increases with the sensitivity. The parameters such as sensitivity and hysteresis of the WO{sub 3} film sensors have been evaluated.

  4. Large area bulk superconductors

    Science.gov (United States)

    Miller, Dean J.; Field, Michael B.

    2002-01-01

    A bulk superconductor having a thickness of not less than about 100 microns is carried by a polycrystalline textured substrate having misorientation angles at the surface thereof not greater than about 15.degree.; the bulk superconductor may have a thickness of not less than about 100 microns and a surface area of not less than about 50 cm.sup.2. The textured substrate may have a thickness not less than about 10 microns and misorientation angles at the surface thereof not greater than about 15.degree.. Also disclosed is a process of manufacturing the bulk superconductor and the polycrystalline biaxially textured substrate material.

  5. Improved gas sensing and dielectric properties of Fe doped hydroxyapatite thick films: Effect of molar concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Mene, Ravindra U. [PDEA' s, Annasaheb Waghire College of Science, Arts and Commerce, Otur 412409, M.S. (India); School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, M.S. (India); Mahabole, Megha P. [School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, M.S. (India); Mohite, K.C. [Haribhai. V. Desai College, Pune 411002, M.S. (India); Khairnar, Rajendra S., E-mail: rskhairnarsps@gmail.com [School of Physical Sciences, Swami Ramanand Teerth Marathwada University, Nanded 431606, M.S. (India)

    2014-02-01

    Highlights: • We report improved gas sensing and dielectric characteristics of Fe ion exchanged HAp films. • Fe doped HAp film shows maximum gas response at relatively lower temperature. • Response and gas uptake capacity of sensors is improved for appropriate amount of Fe ions in HAp matrix. • Fe-HAp films exhibit remarkable improvement in dielectric properties compared to pure HAp. • Fe doped HAp films show significant improvement in gas sensing as well as in dielectric properties. - Abstract: In the present work Fe doped hydroxyapatite (Fe-HAp) thick films has been successfully utilized to improve the gas sensing as well as its dielectric properties. Initially, HAp nano powder is synthesized by chemical precipitation process and later on Fe ions are doped in HAp by ion exchange process. Structural and morphological modifications are observed by means of X-ray diffraction and scanning electron microscopy analysis. The sensing parameters such as operating temperature, response/recovery time and gas uptake capacity are experimentally determined. The Fe-HAp (0.05 M) film shows improved CO and CO{sub 2} gas sensing capacity at lower operating temperature compared to pure HAp. Moreover, variation of dielectric constant and dielectric loss for pure and Fe-HAp thick films are studied as a function of frequency in the range of 10 Hz–1 MHz. The study reveals that Fe doped HAp thick films improve the sensing and dielectric characteristics as compared to pure HAp.

  6. Effect of Nanoscale Ag Film Thickness on the Electrical and Optical Properties of Transparent IZTO/Ag/IZTO Multilayer Films Deposited on Glass Substrates.

    Science.gov (United States)

    Oh, Dohyun; Lee, Nam Hyun; Cho, Woon-Jo; Kim, Tae Whan

    2015-07-01

    The effect of nanoscale Ag film thickness on the electrical and optical properties in transparent conducting oxide films consisting of an IZTO/Ag/IZTO multilayer were investigated. The homoge- neous morphologies of the Ag films sandwiched between the IZTO films affected the optical and electrical properties of the IZTO/Ag/IZTO multilayer films. The transmittance and resistivity of the IZTO/Ag/IZTO multilayer films decreased with increasing Ag film thickness. The resistivities of the IZTO/Ag/IZTO multilayer films grown on glass substrates were decreased by using an Ag thin inter- layer in comparison with that of the IZTO single layer.

  7. The influence of the Al stabilizer layer thickness on the normal zone propagation velocity in high current superconductors

    CERN Document Server

    Shilon, I.; Langeslag, S.A.E.; Martins, L.P.; ten Kate, H.H.J.

    2015-01-01

    The stability of high-current superconductors is challenging in the design of superconducting magnets. When the stability requirements are fulfilled, the protection against a quench must still be considered. A main factor in the design of quench protection systems is the resistance growth rate in the magnet following a quench. The usual method for determining the resistance growth in impregnated coils is to calculate the longitudinal velocity with which the normal zone propagates in the conductor along the coil windings. Here, we present a 2D numerical model for predicting the normal zone propagation velocity in Al stabilized Rutherford NbTi cables with large cross section. By solving two coupled differential equations under adiabatic conditions, the model takes into account the thermal diffusion and the current redistribution process following a quench. Both the temperature and magnetic field dependencies of the superconductor and the metal cladding materials properties are included. Unlike common normal zon...

  8. Effect of Nanotube Film Thickness on the Performance of Nanotube-Silicon Hybrid Solar Cells

    Directory of Open Access Journals (Sweden)

    Daniel D. Tune

    2013-12-01

    Full Text Available The results of measurements on solar cells made from randomly aligned thin films of single walled carbon nanotubes (SWCNTs on n-type monocrystalline silicon are presented. The films are made by vacuum filtration from aqueous TritonX-100 suspensions of large diameter arc-discharge SWCNTs. The dependence of the solar cell performance on the thickness of the SWCNT film is shown in detail, as is the variation in performance due to doping of the SWCNT film with SOCl2.

  9. Self-ordering of random intercalates in thin films of cuprate superconductors: Growth model and x-ray diffraction diagnosis

    Science.gov (United States)

    Ariosa, D.; Cancellieri, C.; Lin, P. H.; Pavuna, D.

    2007-05-01

    We propose a simple model for the nucleation of random intercalates during the growth of high-temperature superconductor (HTSC) films by pulsed laser deposition (PLD). The model predicts a very particular spatial distribution of defects: a Markovian-like sequence of displacements along the growth direction ( c axis), as well as a two-component in-plane correlation function, characteristic of self-organized intercalates. A model for x-ray diffraction (XRD) on such structures is also developed and accounts for both c -axis and in-plane anomalies observed in XRD experiments. The method presented in this work constitutes a useful characterization tool in the optimization of deposition parameters for the growth of HTSC films.

  10. Effects of α-particle beam irradiation on superconducting properties of thin film MgB2 superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Bum; Duong, Pham van; Ha, Dong Hyup; Oh, Young Hoon; Kang, Won Nam; Chai, Jong Seo [Sungkunkwan Univeversity, Suwon (Korea, Republic of); Hong, Seung Pyo; Kim, Ran Young [Kore Institute of Radiological and Medical Science, Seoul (Korea, Republic of)

    2016-06-15

    Superconducting properties of thin film MgB2 superconductors irradiated with 45 MeV α-particle beam were studied. After the irradiation, enhancement of the critical current density and pinning force was observed, scaling close to strong pinning formula. Double logarithmic plots of the maximum pinning force density with irreversible magnetic field show a power law behavior close to carbon-doped MgB2 film or polycrystals. Variation of normalized pinning force density in the reduced magnetic field suggests scaling formulas for strong pinning mechanism like planar defects. We also observed a rapid decay of critical current density as the vortex lattice constant decreases, due to the strong interaction between vortices and increasing magnetic field.

  11. Thickness dependence of structural, electrical and optical behaviour of undoped ZnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bouderbala, M.; Hamzaoui, S. [Laboratoire de Microscopie Electronique et des Sciences des Materiaux, Departement de Physique, USTO, B.P. 1505, El-Mnaouer, 31000 Oran (Algeria); Amrani, B. [Department of Physics, Centre Universitaire de Mascara, Mascara 29000 (Algeria)], E-mail: abouhalouane@yahoo.fr; Reshak, Ali H. [Institute of Physical Biology-South Bohemia University, Institute of System Biology and Ecology-Academy of Sciences, Nove Hrady 37333 (Czech Republic); Adnane, M.; Sahraoui, T.; Zerdali, M. [Laboratoire de Microscopie Electronique et des Sciences des Materiaux, Departement de Physique, USTO, B.P. 1505, El-Mnaouer, 31000 Oran (Algeria)

    2008-09-01

    Undoped ZnO thin films of different thicknesses were prepared by r.f. sputtering in order to study the thickness effect upon their structural, morphological, electrical and optical properties. The results suggest that the film thickness seems to have no clear effect upon the orientation of the grains growth. Indeed, the analysis with X-ray diffraction show that the grains were always oriented according to the c(0 0 2)-axis perpendicular to substrate surface whatever the thickness is. However, the grain size was influenced enough by this parameter. An increase in the grain size versus the thickness was noted. For the electrical properties, measurements revealed behaviour very dependent upon thickness. The resistivity decreased from 25 to 1.5x10{sup -3} {omega} cm and the mobility increased from 2 to 37 cm{sup 2} V{sup -1} s{sup -1} when the thickness increased from 70 to 1800 nm while the carrier concentration seems to be less affected by the film thickness and varied slightly remaining around 10{sup 20} cm{sup -3}. Nevertheless, a tendency to a decrease was noticed. This behaviour in electrical properties was explained by the crystallinity and the grain size evolution. The optical measurements showed that all the samples have a strong transmission higher than 80% in the visible range. A slight shift of the absorption edge towards the large wavelengths was observed as the thickness increased. This result shows that the band gap is slightly decreases from 3.37 to 3.32 eV with the film thickness vary from 0.32 to 0.88 {mu}m.

  12. Thick barium ferrite films use for passive isolators

    Energy Technology Data Exchange (ETDEWEB)

    Capraro, Stephane; Chatelon, Jean Pierre; Rouiller, Thomas; Rousseau, Jean Jacques [DIOM, University of Saint-Etienne, 23 rue Michelon, 42023 Saint-Etienne cedex (France); Berre, Martine Le; Barbier, Daniel [LPM, UMR 5511, INSA Lyon, 7 av. Jean Capelle, 69621 Villeurbanne cedex (France); Joisten, Helene [CEA-LETI, 17 rue des martyrs, 38041 Grenoble cedex (France)

    2004-12-01

    Ferrites have magnetic properties suitable for electronic applications, especially in the microwave range (circulators and isolators). Hexagonal ferrite, such as barium ferrite, are of great interest for microwave device applications because of their large resistivity and high permeability at high frequencies. BaM films are deposited under optimized conditions by RF magnetron sputtering on alumina substrates. In order to crystallize the films that are amorphous after deposition, a post deposition annealing at 800 C is implemented. All samples present a good crystallization, a smooth surface and a good in-depth uniformity. The magnetic properties of BaM films show an optimized coercive force and saturation magnetization of 330 kA/m and 500 mT respectively. These values are close to that of the bulk BaM. Isolators are then realized and measured by a vector network analyzer and a probing system. Results on transmission coefficients show a non reciprocal effect, which reaches 8.3 dB/cm at 50 GHz. This proves that such a component behaves like an isolator in the 50 GHz band. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Unusual Contact-Line Dynamics of Thick Films and Drops

    Science.gov (United States)

    Veretennikov, Igor; Agarwal, Abhishek; Indeikina, Alexandra; Chang, Hsueh-Chia

    1999-01-01

    We report several novel phenomena In contact-line and fingering dynamics of macroscopic spinning drops and gravity-driven films with dimensions larger than the capillary length. It is shown through experimental and theoretical analysis that such macroscopic films can exhibit various interfacial shapes, including multi valued ones, near the contact line due to a balance between the external body forces with capillarity. This rich variety of front shapes couples with the usual capillary, viscous, and intermolecular forces at the contact line to produce a rich and unexpected spectrum of contact-line dynamics. A single finger develops when part of the front becomes multivalued on a partially wetting macroscopic spinning drop in contrast to a different mechanism for microscopic drops of completely wetting fluids. Contrary to general expectation, we observe that, at high viscosity and low frequencies of rotation, the speed of a glycerine finger increases with increasing viscosity. Completely wetting Dow Corning 200 Fluid spreads faster over a dry inclined plane than a prewetted one. The presence of a thin prewetted film suppresses fingering both for gravity-driven flow and for spin coating. We analyze some of these unique phenomena in detail and offer qualitative physical explanations for the others.

  14. Critical thickness for ferromagnetism in insulating LaMnO3 films

    Science.gov (United States)

    Renshaw Wang, X.; Poccia, N.; Leusink, D. P.; Paudel, Tura R.; Tsymbal, E. Y.; Li, C. J.; Lv, W. M.; Venkatesan, T.; Ariando, Ariando; Hilgenkamp, H.

    2014-03-01

    The interplay between exchange interactions, interfacial charges, and confinement effects controls the electronic, magnetic, and transport properties of complex oxide thin films. Here we report the emergence of ferromagnetism in insulating LaMnO3 thin films grown on SrTiO3 substrates beyond a critical thickness. LaMnO3 (001) films are deposited by a pulsed laser deposition technique with thicknesses varying from 1 unit cell to 24 unit cells. The position dependent local magnetization is then mapped with micrometer resolution using scanning superconducting quantum interference device microscopy. We find that the magnetic ground state switches from non-ferromagnetic to ferromagnetic within a change of one unit cell above the critical thickness of 5 unit cells with characteristic domain size of about 20 μm. Further increase of film thickness up to 24 unit cells leads to reduction of the domain size to about 10 μm. The critical thickness is qualitatively explained in terms of the charge transfer in polar LaMnO3 (001) thin films based on results of additional experimental data, density-functional calculations, and the electrostatic modeling.

  15. Modelling and optimization of film thickness variation for plasma enhanced chemical vapour deposition processes

    Science.gov (United States)

    Waddell, Ewan; Gibson, Des; Lin, Li; Fu, Xiuhua

    2011-09-01

    This paper describes a method for modelling film thickness variation across the deposition area within plasma enhanced chemical vapour deposition (PECVD) processes. The model enables identification and optimization of film thickness uniformity sensitivities to electrode configuration, temperature, deposition system design and gas flow distribution. PECVD deposition utilizes a co-planar 300mm diameter electrodes with separate RF power matching to each electrode. The system has capability to adjust electrode separation and electrode temperature as parameters to optimize uniformity. Vacuum is achieved using dry pumping with real time control of butterfly valve position for active pressure control. Comparison between theory and experiment is provided for PECVD of diamond-like-carbon (DLC) deposition onto flat and curved substrate geometries. The process utilizes butane reactive feedstock with an argon carrier gas. Radiofrequency plasma is used. Deposited film thickness sensitivities to electrode geometry, plasma power density, pressure and gas flow distribution are demonstrated. Use of modelling to optimise film thickness uniformity is demonstrated. Results show DLC uniformity of 0.30% over a 200 mm flat zone diameter within overall electrode diameter of 300mm. Thickness uniformity of 0.75% is demonstrated over a 200mm diameter for a non-conformal substrate geometry. Use of the modelling method for PECVD using metal-organic chemical vapour deposition (MOCVD) feedstock is demonstrated, specifically for deposition of silica films using metal-organic tetraethoxy-silane. Excellent agreement between experimental and theory is demonstrated for conformal and non-conformal geometries. The model is used to explore scalability of PECVD processes and trade-off against film thickness uniformity. Application to MEMS, optical coatings and thin film photovoltaics is discussed.

  16. Thickness, morphology, and optoelectronic characteristics of pristine and surfactant-modified DNA thin films

    Science.gov (United States)

    Arasu, Velu; Reddy Dugasani, Sreekantha; Son, Junyoung; Gnapareddy, Bramaramba; Jeon, Sohee; Jeong, Jun-Ho; Park, Sung Ha

    2017-10-01

    Although the preparation of DNA thin films with well-defined thicknesses controlled by simple physical parameters is crucial for constructing efficient, stable, and reliable DNA-based optoelectronic devices and sensors, it has not been comprehensively studied yet. Here, we construct DNA and surfactant-modified DNA thin films by drop-casting and spin-coating techniques. The DNA thin films formed with different control parameters, such as drop-volume and spin-speed at given DNA concentrations, exhibit characteristic thickness, surface roughness, surface potential, and absorbance, which are measured by a field emission scanning electron microscope, a surface profilometer, an ellipsometer, an atomic force microscope, a Kelvin probe force microscope, and an UV–visible spectroscope. From the observations, we realized that thickness significantly affects the physical properties of DNA thin films. This comprehensive study of thickness-dependent characteristics of DNA and surfactant-modified DNA thin films provides insight into the choice of fabrication techniques in order for the DNA thin films to have desired physical characteristics in further applications, such as optoelectronic devices and sensors.

  17. WS{sub 2} nanotube formation by sulphurization: Effect of precursor tungsten film thickness and stress

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Sheung Mei; Wong, Hon Fai; Wong, Wang Cheung; Tan, Choon Kiat; Choi, Sin Yuk; Mak, Chee Leung; Li, Gui Jun [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Dong, Qing Chen [MOE Key Laboratory for Interface Science and Engineering in Advanced Materials and Research Center of Advanced Materials Science and Technology, Taiyuan University of Technology, 79 Yingze West Street, Taiyuan 030024 (China); Leung, Chi Wah, E-mail: dennis.leung@polyu.edu.hk [Department of Applied Physics, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2016-09-15

    Transition metal dichalcogenides can exhibit as 2-dimensional layers, 1-dimensional nanotubes or 0-dimensional quantum dot structures. In general, dichalcogenide nanotubes are grown under stringent conditions, using high growth temperatures with tedious processes. Here, we report the controlled formation of tungsten disulphide (WS{sub 2}) nanostructures by manipulating the precursor film thickness, followed by a direct sulphurization process. WS{sub 2} nanotubes were formed by ultra-thin tungsten precursor films, while particle-like WS{sub 2} were obtained from thicker tungsten films under identical sulphurization conditions. To elucidate the origin of WS{sub 2} nanostructure formation, micron-sized tungsten film tracks were prepared, and such patterned films were found to suppress the growth of WS{sub 2} nanotubes. We attribute the suppression of nanotube formation to the relieving of film stress in patterned precursor films. - Highlights: • WS{sub 2} were obtained by sulphurization of sputtered tungsten films on Si substrates. • Resultant WS{sub 2} nanostructure morphology was dependent on precursor film thickness. • Patterning into micro-size W tracks suppressed the formation of nanotubes. • Stress relaxation was attributed as controlling factor for WS{sub 2} structure formation.

  18. Microdomain orientation dependence on thickness in thin films of cylinder-forming PS-b-PMMA.

    Science.gov (United States)

    Zucchi, I A; Poliani, E; Perego, M

    2010-05-07

    The self-assembly of block-copolymer thin films in periodic nanostructures has received considerable attention during the last decade due to their potential applications in nanofabrication and nanolithography. We followed the morphologies developed in thin films of a cylinder-forming diblock copolymer polystyrene-b-poly(methylmethacrylate) ((PS-b-PMMA), PS 46.1 kg mol( - 1), PMMA 21.0 kg mol( - 1), lattice spacing L(0) = 36 nm), as a function of the film thickness (t), analyzing the effect of thickness commensurability on domain orientation in respect to the substrate. The study was circumscribed to the unexplored range of thickness below L(0). Two thickness windows with perpendicular orientation of the PMMA domains were identified: a well-known window at t approximately L(0) and a new window at t approximately L(0)/2. A half-parallel cylinder morphology was observed for [Formula: see text] with a progressive change in morphology [Formula: see text] when thickness increases from L(0)/2 to L(0). This experimental evidence provides new insights on the mechanism of block copolymers self-organization and indicates the possibility to tune the thickness of the nanostructured polymeric film below L(0), allowing the fabrication of ultrathin soft masks for advanced lithographic processes.

  19. Formulation and Characterization of Cu Doped ZnO Thick Films as LPG Gas Sensor

    Directory of Open Access Journals (Sweden)

    A. V. PATIL

    2010-12-01

    Full Text Available Thick films of pure and various concentrations (1 wt. %, 3 wt. %, 5 wt. %, 7 wt. % and 10 wt. % of Cu-doped ZnO were prepared on alumina substrates using a screen printing technique. These films were fired at a temperature of 700ºC for two hours in an air atmosphere. Morphological, compositional and structural properties of the samples were obtained using the scanning electron microscopy (SEM, Energy dispersive spectroscopy (EDAX and X-ray diffraction techniques respectively. The LPG gas sensing properties of these thick films were investigated at different operating temperatures and LPG gas concentrations. The surface resistance of thick films decreases when exposed to LPG gas. The Cu doped films show significant sensitivity to LPG gas than pure ZnO film. 5 wt. % Cu-doped ZnO film was found to be more sensitive (87.3 % to LPG gas exposed at 300 oC than other doping concentrations with fast response and recovery time.

  20. Terahertz ultrathin film thickness sensor below λ/90 based on metamaterial.

    Science.gov (United States)

    Chen, Meng; Fan, Fei; Shen, Si; Wang, Xianghui; Chang, Shengjiang

    2016-08-10

    The film thickness sensing based on metamaterial is investigated in the terahertz (THz) region. We fabricated the metamaterial sensor, and demonstrated its resonance by using the THz time-domain spectroscopy system. The results show that the resonant dip redshifts as the film thickness increases, which achieves reliable film sensing in the THz band. Its sensitivity is larger than 9.4 GHz/μm with a film thinner than λ/90. Meanwhile, the sensing mechanism is revealed by the simulation of near-field resonance distribution, which shows that the resonant intensity is stronger when the field is closer to the interface between the metamaterial surface and polyvinyl alcohol film. Therefore, the nonlinear type of the sensing sensitivity in our experiment can be well explained, and a higher sensitive sensing can be obtained when the film thickness is smaller. This simple and flexible method can realize the ultrathin film sensing in the THz region, and has application potential in the real-time monitoring of sample quality.

  1. Melt process of Sm-Ba-Cu-O bulk superconductors by thin film cold seeding

    Science.gov (United States)

    Fujimoto, H.; Ozaku, H.; Ohtabara, E.

    2003-10-01

    We discuss Sm123 bulks melt-processed in air and their characteristic superconducting properties for improving superconducting properties and producing a larger bulk. Isothermal undercooling growth in air with oxygen annealing and Nd123/MgO thin film cold seeding technique were applied in SmBaCuOy/Ag system to seek the high-efficiency of process, homogeneity of composition, and feasibility of batch production. We investigated process conditions such as heat treatment temperatures, compositions, seeding methods, and atmosphere. Single-domain growth of superconducting phases of a square larger than 10 mm on a side and 5 mm in thickness was achieved using this technique. Tc,onset and Tc,zero are 94 and 90 K, and Jc is 3 × 10 4 A/cm 2 at around 2 T at 77 K with a typical peak effect in the LRE system. In the case of Sm211 = 10 and 40 mol% addition, the maximum trapped magnetic field of the bulks is 1000 and 2100 G, respectively. The maximum magnetic field increases as Sm211 volume fractions increase. The result implies that melt-processed in air applying isothermal method and thin film seeding in Sm system is feasible for producing larger bulks in large scale applications.

  2. Study of $\\beta$-phase development in spin-coated PVDF thick films

    Indian Academy of Sciences (India)

    BHOOPESH MAHALE; DHANANJAY BODAS; S A GANGAL

    2017-06-01

    A study was conducted to ascertain the effect of variation in spin speed and baking temperature on $\\beta$-phase content in the spin-coated poly(vinylidene fluoride) (PVDF) thick films ($\\sim$4−25 $\\mu$m). Development of $\\beta$-phase is dependent on film stretching and crystallization temperature. Therefore, to study the development of $\\beta$-phase in films, stretching is achieved by spinning and crystallization temperature is adjusted by means of baking. PVDF films are characterized using Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and scanning electronmicroscopy. It is observed that crystallization temperature lower than 60$^{\\circ}$C and increase in spin speed increases the $\\beta$-phasecontent in PVDF films. Crystallization temperature above 60$^{\\circ}$C reduces $\\beta$-phase content and increases α-phase content. It was also observed that viscosity of the PVDF solution affects the β-phase development in films at a particular spin speed.

  3. Bio-interfaces--interaction of PLL/HA thick films with nanoparticles and microcapsules.

    Science.gov (United States)

    Skirtach, Andre G; Volodkin, Dmitry V; Möhwald, Helmuth

    2010-03-15

    The interaction of biocompatible, exponentially grown films composed of poly-L-lysine (PLL) and hyaluronic acid (HA) polymers with gold nanoparticles and microcapsules is studied. Both aggregated and non-aggregated nanoparticle states are achieved; desorption of PLL accounts for aggregation of nanoparticles. The presence of aggregates of gold nanoparticles on films enables remote activation by near-infrared irradiation due to local, nanometer confined heating. Thermally shrunk microcapsules, which are remarkably monodisperse upon preparation but gain polydispersity after months of storage, are also adsorbed onto films. PLL polymers desorbed from films interact with microcapsules introducing a charge imbalance which leads to an increase of the microcapsule size, thus films amplify this effect. Multifunctional, biocompatible, thick gel films with remote activation and release capabilities are targeted for cell cultures in biology and tissue engineering in medicine.

  4. Adsorbed films of three-patch colloids: Continuous and discontinuous transitions between thick and thin films

    Science.gov (United States)

    Dias, C. S.; Araújo, N. A. M.; Telo da Gama, M. M.

    2014-09-01

    We investigate numerically the role of spatial arrangement of the patches on the irreversible adsorption of patchy colloids on a substrate. We consider spherical three-patch colloids and study the dependence of the kinetics on the opening angle between patches. We show that growth is suppressed below and above minimum and maximum opening angles, revealing two absorbing phase transitions between thick and thin film regimes. While the transition at the minimum angle is continuous, in the directed percolation class, that at the maximum angle is clearly discontinuous. For intermediate values of the opening angle, a rough colloidal network in the Kardar-Parisi-Zhang universality class grows indefinitely. The nature of the transitions was analyzed in detail by considering bond flexibility, defined as the dispersion of the angle between the bond and the center of the patch. For the range of flexibilities considered we always observe two phase transitions. However, the range of opening angles where growth is sustained increases with flexibility. At a tricritical flexibility, the discontinuous transition becomes continuous. The practical implications of our findings and the relation to other nonequilibrium transitions are discussed.

  5. Magnetic levitation performance of high-temperature superconductor over three magnetic hills of permanent magnet guideway with iron shims of different thicknesses

    Institute of Scientific and Technical Information of China (English)

    Yuming Gong; Gang Liang; Lifeng Zhao; Yong Zhang; Yong Zhao; Xuyong Chen

    2014-01-01

    Superconducting magnetic levitation perfor-mance, including levitation force and guidance force, is important for the application of high-temperature super-conducting maglev. Both of them are not only affected by different arrays of superconductors and magnets, but also by the thickness of the iron shim between permanent magnets. In order to obtain the best levitation performance, the magnetic field distribution, levitation force, and guid-ance force of a new type of three magnetic hills of per-manent magnet guideway with iron shim of different thicknesses (4, 6, and 8 mm) are discussed in this paper. Simulation analysis and experiment results show that the guideway with iron shim of 8 mm thickness possesses the strongest magnetic field and levitation performance when the suspension gap is larger than 10 mm. However, with the decreasing of suspension gap, the guideway with iron shim of 4 mm thickness possesses the best levitation per-formance. The phenomena can be attributed to the density distribution of flux and magnetization of iron shim.

  6. High-performance piezoelectric thick film based energy harvesting micro-generators for MEMS

    DEFF Research Database (Denmark)

    Zawada, Tomasz; Hansen, Karsten; Lou-Moeller, Rasmus

    2010-01-01

    Energy harvesting, known also as energy scavenging, covers a great body of technologies and devices that transform low grade energy sources such as solar energy, environmental vibrations, thermal energy, human motion into usable electrical energy. In this paper vibrations are used as energy source...... and are transformed by the energy harvesting micro-generator into usable electrical signal. The micro-generator comprises a silicon cantilever with integrated InSensor® TF2100 PZT thick film deposited using screen-printing. The output power versus frequency and electrical load has been investigated. Furthermore......, devices based on modified, pressure treated thick film materials have been tested and compared with the commercial InSensor® TF2100 PZT thick films. It has been found that the structures based on the pressure treated materials exhibit superior properties in terms of energy output....

  7. Mems-based pzt/pzt bimorph thick film vibration energy harvester

    DEFF Research Database (Denmark)

    Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian

    2011-01-01

    We describe fabrication and characterization of a significantly improved version of a MEMS-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The main advantage of bimorph vibration energy harvesters is that strain energy is not lost in mechanical...... support materials since only PZT is strained, and thus it has a potential for significantly higher output power. An improved process scheme for the energy harvester resulted in a robust fabrication process with a record high fabrication yield of 98.6%. Moreover, the robust fabrication process allowed...... a high pressure treatment of the screen printed PZT thick films prior to sintering, improving the PZT thick film performance and harvester power output reaches 37.1 μW at 1 g....

  8. Critical heat flux enhancement regarding to the thickness of graphene films under pool boiling

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Man; Park, Hyun Sun [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of); Park, Youngjae; Kim, Hyungdae [Kyung Hee Univ., Yongin (Korea, Republic of); Kim, Dong Eok [Kyungpook Nat. Univ., Sangju (Korea, Republic of); Kim, Moo Hwan [Korea Inst. of Nuclear Safety, Daejeon (Korea, Republic of); Ahn, Ho Seon [Incheon Nat. Univ., Incheon (Korea, Republic of)

    2014-05-15

    The large thermal conductivity of the graphene films inhibits the formation of hot spots, thereby increasing the CHF. An infrared high-speed visualization showed graphene effect on boiling characteristics during operation. The graphene-coated heater showed an increase in BHT and CHF. As the thickness of the graphene films increased, the CHF also increased up to an asymptotic limit when the graphene layer was approximately 150 nm thick. The increased BHT was explained by the slight decrease in the wettability and the folded edges of the RGO flakes, which led to a decrease in the diameter of the departing bubbles, a larger bubble generation frequency, and an increase in the areal density of the bubble nucleation sites. The increase in the CHF was explained by considering the thermal activity of the graphene films, and the dependence thereof on the thickness and thermal properties of the layer, which was calculated based on high-speed IR visualization data.

  9. (100)-Textured KNN-based thick film with enhanced piezoelectric property for intravascular ultrasound imaging

    Science.gov (United States)

    Zhu, Benpeng; Zhang, Zhiqiang; Ma, Teng; Yang, Xiaofei; Li, Yongxiang; Shung, K. Kirk; Zhou, Qifa

    2015-04-01

    Using tape-casting technology, 35 μm free-standing (100)-textured Li doped KNN (KNLN) thick film was prepared by employing NaNbO3 (NN) as template. It exhibited similar piezoelectric behavior to lead containing materials: a longitudinal piezoelectric coefficient (d33) of ˜150 pm/V and an electromechanical coupling coefficient (kt) of 0.44. Based on this thick film, a 52 MHz side-looking miniature transducer with a bandwidth of 61.5% at -6 dB was built for Intravascular ultrasound (IVUS) imaging. In comparison with 40 MHz PMN-PT single crystal transducer, the rabbit aorta image had better resolution and higher noise-to-signal ratio, indicating that lead-free (100)-textured KNLN thick film may be suitable for IVUS (>50 MHz) imaging.

  10. Thickness-dependent magnetic properties of Ce{sub 9}Fe{sub 91} films

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xueyun; Wang, Dianyuan; Yu, Jianmin [Faculty of Science, Jiujiang University, Jiujiang City, Jiangxi Province (China); Wang, Zhenkun; Ge, Shihui [Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University (China); Yao, Dongsheng [Tianjin Key Laboratory of Low-Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University (China)

    2014-12-01

    Ce{sub 9}Fe{sub 91} films with different thickness were fabricated by a rf magnetron sputtering method. The critical thickness t{sub c} for spin reorientation transition has been determined to be approximately 90 nm using the stripe domain model and magnetic force microscope. Above t{sub c}, the films exhibit Bloch stripe domain structure and a superhigh resonance frequency at 6 GHz is found for the parallel stripe configuration. However, below t{sub c}, the films possess an in-plane uniaxial anisotropy caused by order interface tension between the film and substrate, and the resonance frequency breaks through the Snoek limit. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Thick growing multilayer nanobrick wall thin films: super gas barrier with very few layers.

    Science.gov (United States)

    Guin, Tyler; Krecker, Michelle; Hagen, David Austin; Grunlan, Jaime C

    2014-06-24

    Recent work with multilayer nanocoatings composed of polyelectrolytes and clay has demonstrated the ability to prepare super gas barrier layers from water that rival inorganic CVD-based films (e.g., SiOx). In an effort to reduce the number of layers required to achieve a very low oxygen transmission rate (OTR (layer-by-layer (LbL) assembly. Buffering the chitosan solution and its rinse with 50 mM Trizma base increased the thickness of these films by an order of magnitude. The OTR of a 1.6-μm-thick, six-bilayer film was 0.009 cc/m(2)·day·atm, making this the best gas barrier reported for such a small number of layers. This simple modification to the LbL process could likely be applied more universally to produce films with the desired properties much more quickly.

  12. Multifunctional thick-film structures based on spinel ceramics for environment sensors

    Energy Technology Data Exchange (ETDEWEB)

    Vakiv, M; Hadzaman, I; Klym, H; Shpotyuk, O [Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, 79031 (Ukraine); Brunner, M, E-mail: shpotyuk@novas.lviv.ua, E-mail: klymha@yahoo.com [Fachhochschule Koeln/University of Applied Sciences, 2 Betzdorfer str., Koeln, 50679 (Germany)

    2011-04-01

    Temperature sensitive thick films based on spinel-type NiMn{sub 2}O{sub 4}-CuMn{sub 2}O{sub 4}-MnCo{sub 2}O{sub 4} manganites with p- and p{sup +}-types of electrical conductivity and their multilayer p{sup +}-p structures were studied. These thick-film elements possess good electrophysical characteristics before and after long-term ageing test at 170 deg. C. It is shown that degradation processes connected with diffusion of metallic Ag into film grain boundaries occur in one-layer p-and p{sup +}-conductive films. Some part of the p{sup +}-p structures were of high stability, the relative electrical drift being no more than 1 %.

  13. Thick and hard anodized aluminum film with large pores for surface composites

    Institute of Scientific and Technical Information of China (English)

    WANG Hui; WANG Hao-wei

    2004-01-01

    Al-base surface self-lubricating composites need thick and hard alumina membranes with large pores to add lubricants easily. This kind of porous alumina layer was fabricated in additive-containing, phosphoric acid-based solution. The effects of additive containing organic carboxylic acid and Ce salt on the properties of the oxide film and mechanism were investigated in detail with SEM and EDAX analyses. The results show that the pore diameter is about 100 nm, the film thickness increases by 4 -5 times, and the Vickers hardness improves by about 50% through adding some amount of organic carboxylic acid and Ce salt. Such an improvement in properties is explained in terms of a lower film dissolving velocity and better film quality in compound solution.

  14. Interference-aided spectrum fitting method for accurately film thickness determination

    CERN Document Server

    Liu, Xingxing; Xia, Hui; Zhang, Xutao; Ji, Ruonan; Li, Tianxin; Lu, Wei

    2016-01-01

    A new approach was proposed to accurately determine the thickness of film, especially for ultra-thin film, through spectrum fitting with the assistance of interference layer. The determination limit can reach even less than 1 nm. Its accuracy is far better than traditional methods. This determination method is verified by experiments and the determination limit is at least 3.5 nm compared with the results of AFM. Furthermore, double-interference-aided spectra fitting method is proposed to reduce the requirements of determination instruments, which allow one to determine the film thickness with a low precision common spectrometer and largely lower the cost. It is a very high precision determination method for on-site and in-situ applications, especially for ultra-thin films.

  15. Some limitations in applying classical EHD film-thickness formulae to a high-speed bearing

    Science.gov (United States)

    Coy, J. J.; Zaretsky, E. V.

    1980-01-01

    Elastohydrodynamic film thickness was measured for a 20 mm ball bearing using the capacitance technique. The bearing was thrust loaded to 90, 448, and 778 N. The corresponding maximum stresses on the inner race were 1.28, 2.09, and 2.45 GPa. Test speeds ranged from 400 to 14,000 rpm. Film thickness measurements were taken with four different lubricants: (1) synthetic paraffinic; (2) synthetic paraffinic with additives; (3) neopentylpolyol (tetra) ester; and (4) synthetic cycloaliphatic hydrocarbon traction fluid. The test bearing was mist lubricated. Test temperatures were 300, 338, and 393 K. The measured results were compared to theoretical predictions and are presented.

  16. Laser drilling of vias in dielectric for high density multilayer LSHI thick film circuits

    Science.gov (United States)

    Cocca, T.; Dakesian, S.

    1977-01-01

    A design analysis of a high density multilevel thick film digital microcircuit used for large scale integration is presented. The circuit employs 4 mil lines, 4 mil spaces and requires 4 mil diameter vias. Present screened and fired thick film technology is limited on a production basis to 16 mil square vias. A process whereby 4 mil diameter vias can be fabricated in production using laser technology was described along with a process to produce 4 mil diameter vias for conductor patterns which have 4 mil lines and 4 mil spacings.

  17. Thickness dependent exchange bias in martensitic epitaxial Ni-Mn-Sn thin films

    Directory of Open Access Journals (Sweden)

    Anna Behler

    2013-12-01

    Full Text Available A thickness dependent exchange bias in the low temperature martensitic state of epitaxial Ni-Mn-Sn thin films is found. The effect can be retained down to very small thicknesses. For a Ni50Mn32Sn18 thin film, which does not undergo a martensitic transformation, no exchange bias is observed. Our results suggest that a significant interplay between ferromagnetic and antiferromagnetic regions, which is the origin for exchange bias, is only present in the martensite. The finding is supported by ab initio calculations showing that the antiferromagnetic order is stabilized in the phase.

  18. Thickness and structure of the water film deposited from vapour on calcite surfaces

    DEFF Research Database (Denmark)

    Bohr, Jakob; Wogelius, Roy A.; Morris, Peter M.

    2010-01-01

    Synchrotron X-ray reflectivity (SXR) was used to measure the thickness of the water film that adsorbs on a {10¯14} cleavage surface of calcite (CaCO3) in a sample chamber where relative humidity could be controlled within the range from......Synchrotron X-ray reflectivity (SXR) was used to measure the thickness of the water film that adsorbs on a {10¯14} cleavage surface of calcite (CaCO3) in a sample chamber where relative humidity could be controlled within the range from...

  19. Piezoelectric sensors to monitor lubricant film thickness at piston-cylinder contacts in a fired engine

    OpenAIRE

    2013-01-01

    The contact between the piston ring and cylinder liner is the most important sealing interface in an automotive engine. Understanding the contact interactions and lubricant film formation at this interface is crucial for the development of fuel-efficient and low emission engines. This article outlines the development of an ultrasonic approach to enable non-invasive measurement of the lubricant film thickness formed between piston and cylinder wall of a fired engine. The sensor system consiste...

  20. MgB2 thick films with remarkable ductility on stainless steel substrate

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Cheng-gang; AN Ling; CHEN Li-ping; DING Li-li; ZHANG Kai-cheng; CHEN Chin-ping; XU Jun; FENG Qing-rong; GAN Zi-zhao

    2006-01-01

    We fabricated several superconducting MgB2 thick films on stainless steel (SS) substrates by using hybrid physical-chemical vapor deposition (HPCVD) technique.The thickness was in the 10 pμm to 20 pμm range,and the onset critical transition temperature Te (onset) and the width of the superconducting transition ( △ T) were about 37.8 and 1.2 K.They were dense and textured along (101) direction with high tenacity,despite the existence of a little amount of MgO and Mg.We bent the films at different degrees and studied the ductility and transport properties of these MgB2 thick films under applied force.The results demonstrated that the superconducting properties of these thick films,prepared by HPCVD,stay almost unaffected even with the films bent to a large degree with a curvature of 0.5 nun.This indicated that the superconducting wires or tapes of MgB2 with a core of SS had the advantages of avoiding rigidity and brittleness in industrial handling.The technique of HPCVD has,therefore,a high application potential.

  1. A novel multi-degree-of-freedom thick-film ultrasonic motor.

    Science.gov (United States)

    Aoyagi, Manaba; Beeby, Steve P; White, Neil M

    2002-02-01

    This paper describes a new multi-degree-of-freedom (MDOF) ultrasonic motor that comprises few parts and is based on low-cost thick-film technology. Conventional ultrasonic motors using bulk lead zirconate titanate (PZT) or thin-film PZT layers are relatively expensive at the present time. Thick-film printed PZT technology provides the opportunity to reduce the costs of ultrasonic motors. To demonstrate the feasibility of this approach, an ultrasonic motor was fabricated from alumina using thick-film printed PZT actuators. The thick-film PZT and electrode layers were printed on a thin alumina plate, and a tiny cylinder was mounted at its center. This cylinder magnifies the lateral displacement of the stator, holds the spherical rotor, and transmits the driving force to the sphere. Three bending vibrations, B22, B30, B03, of the plate were applied to rotate the sphere. Sufficient displacements for rotating the sphere were obtained near the resonance of B22 by applying an excitation voltage of 200 V peak-to-peak via a three-phase drive circuit. Rotations in three orthogonal directions have been observed by controlling the phase of the driving signal to the PZT electrodes, and a MDOF ultrasonic motor was successfully realized.

  2. Thickness dependence of structural and optical properties of cadmium iodide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yahia, I.S. [Department of Physics, Faculty of Science, King Khalid University, P.O. Box 9004, Abha (Saudi Arabia); Centre of Nanotechnology, King AbdulAziz University, Jeddah (Saudi Arabia); Shapaan, M. [Department of Physics, Faculty of Science, Al-Azahar University, Cairo (Egypt); Ismail, Yasser A.M.; Aboraia, A.M. [Department of Physics, Faculty of Science, Al-Azahar University, Assiut 71542 (Egypt); Shaaban, E.R., E-mail: esamramadan2008@yahoo.com [Department of Physics, Faculty of Science, Al-Azahar University, Assiut 71542 (Egypt)

    2015-07-05

    Highlights: • Different thicknesses of CdI{sub 2} films were prepared. • Both crystallite size and microstrain of the films has been determined. • The room temperature reflectance and transmittance data are analyzed. • The refractive index and energy gap are determined. - Abstract: Structural and optical properties as a function of film thickness have been studied for the thermally evaporated cadmium iodide (CdI{sub 2}) films. According to XRD structure, the thickness of investigated films extends from 272 to 696 nm, showing hexagonal structure and good c-axis alignment normal to glass substrate plane. Both of crystallite size and lattice strain have been determined in terms of Voight method of the main peak. The optical constants, refractive index (n), and extinction coefficient (k) have been determined using envelope method. The optical absorption data indicates an allowed direct inter – band transition near the absorption edge with an optical energy gap that decreases continuously from 3.572 to 3.767 eV. Both of optical constants and energy gap show thickness dependence that can be explained in terms of structure parameters, crystallite size, and lattice strain.

  3. Ultrasonic oil-film thickness measurement: an angular spectrum approach to assess performance limits.

    Science.gov (United States)

    Zhang, Jie; Drinkwater, Bruce W; Dwyer-Joyce, Rob S

    2007-05-01

    The performance of ultrasonic oil-film thickness measurement in a ball bearing is quantified. A range of different viscosity oils (Shell T68, VG15, and VG5) are used to explore the lowest reflection coefficient and hence the thinnest oil-film thickness that the system can measure. The results show a minimum reflection coefficient of 0.07 for both oil VG15 and VG5 and 0.09 for oil T68 at 50 MHz. This corresponds to an oil-film thickness of 0.4 microm for T68 oil. An angular spectrum (or Fourier decomposition) approach is used to analyze the performance of this configuration. This models the interaction of component plane waves with the measurement system and quantifies the effect of the key parameters (transducer aperture, focal length, and center frequency). The simulation shows that for a focused transducer the reflection coefficient tends to a limiting value at small oil-film thickness. For the transducer used in this paper it is shown that the limiting reflection coefficient is 0.05 and the oil-film measurement errors increase as the reflection coefficient approaches this value. The implications for improved measurement systems are then discussed.

  4. Measurements of liquid film thickness, concentration, and temperature of aqueous urea solution by NIR absorption spectroscopy

    Science.gov (United States)

    Pan, R.; Jeffries, J. B.; Dreier, T.; Schulz, C.

    2016-01-01

    A multi-wavelength near-infrared (NIR) diode laser absorption sensor has been developed and demonstrated for real-time monitoring of the thickness, solute concentration, and temperature of thin films of urea-water solutions. The sensor monitors the transmittance of three near-infrared diode lasers through the thin liquid film. Film thickness, urea mass fraction, and liquid temperature were determined from measured transmittance ratios of suitable combinations of lasers. Available laser wavelengths were selected depending on the variation of the NIR absorption spectrum of the solution with temperature and solute concentration. The spectral database was measured by a Fourier transform infrared spectrometer in the range 5500-8000 cm-1 for urea solutions between 5 and 40 wt% and temperatures between 298 and 338 K. A prototype sensor was constructed, and the sensor concept was first validated with measurements using a calibration cell providing liquid layers of variable thickness (200-1500 µm), urea mass fraction (5-40 wt%) and temperature (298-318 K). Temporal variations of film thickness and urea concentration were captured during the constant-temperature evaporation of a liquid film deposited on an optically polished heated quartz flat.

  5. Effect of film thickness on NO2 gas sensing properties of sprayed orthorhombic nanocrystalline V2O5 thin films

    Science.gov (United States)

    Mane, A. A.; Moholkar, A. V.

    2017-09-01

    The nanocrystalline V2O5 thin films with different thicknesses have been grown onto the glass substrates using chemical spray pyrolysis (CSP) deposition method. The XRD study shows that the films exhibit an orthorhombic crystal structure. The narrow scan X-ray photoelectron spectrum of V-2p core level doublet gives the binding energy difference of 7.3 eV, indicating that the V5+ oxidation state of vanadium. The FE-SEM micrographs show the formation of nanorods-like morphology. The AFM micrographs show the high surface area to volume ratio of nanocrystalline V2O5 thin films. The optical study gives the band gap energy values of 2.41 eV, 2.44 eV, 2.47 eV and 2.38 eV for V2O5 thin films deposited with the thicknesses of 423 nm, 559 nm, 694 nm and 730 nm, respectively. The V2O5 film of thickness 559 nm shows the NO2 gas response of 41% for 100 ppm concentration at operating temperature of 200 °C with response and recovery times of 20 s and 150 s, respectively. Further, it shows the rapid response and reproducibility towards 10 ppm NO2 gas concentration at 200 °C. Finally, NO2 gas sensing mechanism based on chemisorption process is discussed.

  6. Synthesis of thick diamond films by direct current hot-cathode plasma chemical vapour deposition

    CERN Document Server

    Jin Zeng Sun; Bai Yi Zhen; Lu Xian Yi

    2002-01-01

    The method of direct current hot-cathode plasma chemical vapour deposition has been established. A long-time stable glow discharge at large discharge current and high gas pressure has been achieved by using a hot cathode in the temperature range from 1100 degree C to 1500 degree C and non-symmetrical configuration of the poles, in which the diameter of the cathode is larger than that of anode. High-quality thick diamond films, with a diameter of 40-50 mm and thickness of 0.5-4.2 mm, have been synthesized by this method. Transparent thick diamond films were grown over a range of growth rates between 5-10 mu m/h. Most of the thick diamond films have thermal conductivities of 10-12 W/K centre dot cm. The thick diamond films with high thermal conductivity can be used as a heat sink of semiconducting laser diode array and as a heat spreading and isolation substrate of multichip modules. The performance can be obviously improved

  7. Smoothness improvement of micrometer- and submicrometer-thick nanocrystalline diamond films produced by MWPECVD

    Science.gov (United States)

    Cicala, G.; Magaletti, V.; Senesi, G. S.; Tamborra, M.

    2013-04-01

    Thick (around 3 μm) and thin (48-310 nm) nanocrystalline diamond (NCD) films have been produced from Ar-rich CH4/Ar/H2 (1/89/10 %) and H2-rich CH4/H2 (1/99 %) microwave plasmas, respectively. The deposition rate and the nucleation enhancement have been monitored in situ and in real time by pyrometric and laser reflectance interferometry for micrometer- and nanometer-thick films. For thick films, an improvement of the NCD films' smoothness has been obtained by a buffer layer between the films and the treated Si substrate. For thin films, a combinatorial approach, i.e., a treatment of the Si substrate in a suspension of mixed diamond powders of 250 nm and 40-60 μm, has been utilized. The present experimental results show that the buffer layer procedure allows good preservation of the surface of the treated Si substrate and the combinatorial approach promotes effectively the seeding of the Si surface.

  8. Image processing techniques for measuring non-uniform film thickness profiles

    Energy Technology Data Exchange (ETDEWEB)

    Nitta, S.V.; Liu, An-Hong; Plawsky, J.L.; Wayner, P.C. Jr. [Rensselaer Polytechnique Institute, Troy, NY (United States)

    1996-12-31

    The long term objective of this research program is to determine the fluid flow and drying characteristics of thin liquid/solid films using image processing techniques such as Image Analyzing Interferometry (IAI) and Image Scanning Ellipsometry (ISE). The primary purpose of this paper is to present experimental data on the effectiveness of IAI and ISE to measure nonuniform film thickness profiles. Steady-state, non-isothermal profiles of evaporating films were measured using IAI. Transient thickness profiles of a draining film were measured using ISE. The two techniques are then compared and contrasted. The ISE can be used to measure transient as well as steady-state profiles of films with thickness ranging from 1 nm to > 20 {mu}m, whereas IAI can be used to directly measure Steady-state and transient profiles of only films thicker than about 100 nm. An evaluation of the reflected intensity can be used to extend the use of the IAI below 100 nm.

  9. Thickness dependent phase transformation of magnetron-sputtered Ni-Mn-Sn ferromagnetic shape memory alloy thin films

    Energy Technology Data Exchange (ETDEWEB)

    Vishnoi, Ritu; Singhal, Rahul; Kaur, Davinder, E-mail: dkaurfph@iitr.ernet.in [Indian Institute of Technology Roorkee, Functional Nanomaterials Research Laboratory, Department of Physics and Center of Nanotechnology (India)

    2011-09-15

    In this study, the influence of film thickness on the first-order martensite-austenite phase transformation of Ni-Mn-Sn ferromagnetic shape memory alloy thin films has been systematically investigated. Different thicknesses of the Ni-Mn-Sn films (from {approx}100 to 2,500 nm) were deposited by DC magnetron sputtering on Si (100) substrates at 550 Degree-Sign C. X-ray analysis reveals that all the films exhibit austenitic phase with the L2{sub 1} cubic crystal structure at room temperature. The grain size and crystallization extent increase with the increase in film thickness, but the films with thickness above {approx}1,400 nm show structural deterioration due to the formation of MnSn{sub 2} and Ni{sub 3}Sn{sub 4} precipitates. The improvement in the crystallinity of the film with thickness is attributed to the decrease in film-substrate interfacial strain resulting in preferred oriented growth of the films. Temperature-dependent magnetization measurements as well as electrical measurements demonstrate the complete absence of phase transformation for the film of thickness of {approx}120 nm. For thickness greater than 400 nm, film exhibits the structural transformation, and it occurs at higher temperature with better hysteresis as film thickness is increased up to {approx}1,400 nm, after which degradation of phase transformation phenomenon is observed. This degradation is attributed to the disorders present in the films at higher thicknesses. Film with thickness {approx}1,400 nm possesses the highest magnetization with the smallest thermal hysteresis among all the films and therefore best suited for the actuators based on first-order structural phase transformation. Nanoindentation measurements reveal that the higher values of hardness and elastic modulus of about 5.5 and 215.0 GPa obtained in film of 1,014 nm thickness can considerably improve the ductility of ferromagnetic shape memory alloys (FSMA) and their applicability for MEMS applications. The exchange bias

  10. Variation of structure and magnetic properties with thickness of thin Co59Fe26Ni15 films

    OpenAIRE

    Chechenin, NG; van Voorthuysen, EHD; De Hosson, JTM; Boerma, DO

    2005-01-01

    Variations of phase composition and magnetic properties of electrodeposited nanocrystalline Co-Fe-Ni films with film thickness in the range of 50-500 nm were analyzed. The samples were magnetically soft with coercivity in the range H-c = 2-20 Oe and uni axial magnetic anisotropy up to H-k = 20 Oe. It was found that H-c decreases and H-k increases with increasing film thickness. The BCC phase dominates at small film thickness up to about 80 nm and the FCC phase increases when the film growths ...

  11. Effect of Layer and Film Thickness and Temperature on the Mechanical Property of Micro- and Nano-Layered PC/PMMA Films Subjected to Thermal Aging

    Directory of Open Access Journals (Sweden)

    Ahmed Abdel-Mohti

    2015-04-01

    Full Text Available Multilayered polymer films with biomimicking, layered structures have unique microstructures and many potential applications. However, a major limitation of polymer films is the deterioration of mechanical properties in working environments. To facilitate the design and development of multilayered polymer films, the impact of thermal aging on the mechanical behavior of micro- and nano-layered polymer films has been investigated experimentally. The composition of the polymer films that have been studied is 50 vol% polycarbonate (PC and 50 vol% poly(methyl methacrylate (PMMA. The current study focuses on the effect of film and layer thickness and temperature on the mechanical properties of the materials subjected to thermal aging. To study the effect of film and layer thickness, films with the same thickness, but various layer thicknesses, and films with the same layer thickness, but various film thicknesses, were thermally aged at 100 °C in a constant temperature oven for up to six weeks. The results show that as the layer thickness decreases to 31 nm, the film has a higher stiffness and strength, and the trend of the mechanical properties is relatively stable over aging. The ductility of all of the films decreases with aging time. To study the effect of temperature, the films with 4,096 layers (31 nm thick for each layer were aged at 100 °C, 115 °C and 125 °C for up to four weeks. While the 100 °C aging results in a slight increase of the stiffness and strength of the films, the higher aging temperature caused a decrease of the stiffness and strength of the films. The ductility decreases with the aging time for all of the temperatures. The films become more brittle for higher aging temperatures.

  12. Effect of film thickness on the magneto-structural properties of ion beam sputtered transition metal-metalloid FeCoNbB/Si (100) alloy thin films

    Science.gov (United States)

    Gupta, Pooja; Tripathi, Yagyanidhi; Kumar, Dileep; Rai, S. K.; Gupta, Mukul; Reddy, V. R.; Svec, Peter

    2016-08-01

    The structure and magnetic properties of ion beam sputtered transition metal-metalloid FeCoNbB/Si(100) alloy thin film have been studied as a function of film thickness using complementary techniques of x-ray reflectivity (XRR), grazing incidence x-ray diffraction, and magneto optical Kerr effect. Thicknesses of the films range from ˜200 to 1500 Å. The coercivity of all the films ranges between 4 and 14 Oe, which suggests soft magnetic nature of FeCoNbB/Si thin films. Films with thickness up to 800 Å are amorphous in nature and are found to possess uniaxial magnetic anisotropy in the film plane, although no magnetic field was applied during deposition. The presence of the two fold symmetry in such amorphous thin films may be attributed to quenched-in stresses developed during deposition. Upon increasing the film thickness to ˜1200 Å and above, the structure of FeCoNbB films transforms from amorphous to partially nanocrystalline structure and has bcc-FeCo nanocrystalline phase dispersed in remaining amorphous matrix. The crystalline volume fraction (cvf) of the films is found to be proportional to the film thickness. Azimuthal angle dependence of remanence confirms the presence of in-plane four-fold anisotropy (FFA) in the crystalline film with cvf ˜75%. Synchrotron x-ray diffraction measurement using area detector suggests random orientation of crystallites and thus clearly establishes that FFA is not related to texture/cubic symmetry in such polycrystalline thin films. As supported by asymmetric Bragg diffraction measurements, the origin of FFA in such partially crystalline thin film is ascribed to the additional compressive stresses developed in the film upon crystallization. Results indicate that promising soft magnetic properties in such films can be optimized by controlling the film thickness. The revelation of controllable and tunable anisotropy suggests that FeCoNbB thin films can have potential application in electromagnetic applications.

  13. Thickness-Dependent Structural and Optoelectronic Properties of In2O3 Films Prepared by Spray Pyrolysis Technique

    Science.gov (United States)

    Khan, M. A. Majeed; Khan, Wasi

    2016-08-01

    In this work, nanostructured In2O3 thin films with thickness in the range of 40-160 nm were deposited on glass substrates by the chemical spray pyrolysis technique. The microstructural, surface morphology and optical properties were investigated as a function of film thickness through x-ray diffraction, scanning electron microscopy equipped with energy dispersive spectroscopy, atomic force microscopy, Raman spectroscopy, UV-visible spectroscopy and photoluminescence measurements. The x-ray diffraction analysis showed that the deposited films were polycrystalline in nature with a cubic structure having (222) as preferred orientation. The morphological analyses of the samples exhibited uniform and smooth surface of the films with systematical increments in the surface roughness with increasing film thickness. The grain size increased from 9 nm to 13 nm with increasing film thickness. Raman spectroscopy has been employed to study the crystalline quality and the structural disorder of the films. A blue-shift in the energy band gap ( E g) from 3.74 eV to 3.98 eV was observed with the increase of film thickness. Moreover, photoluminescence peaks of the In2O3 films appeared at 443 nm and 527 nm for all films. The thickness had a substantial influence on the microstructural and optical properties as well as on the luminescence intensity of the films. The strategy presented here indicates that the prepared films could be suitable candidates for optoelectronic device applications.

  14. Three dimensional phase field study on the thickness effect of ferroelectric polymer thin film

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The electromechanical behavior of poly(vinylidene fluoride-trifluoroethylene)[P(VDF -TrFE)]ferroelectric thin film was investigated using the three dimensional(3D) phase-field method. Various energetic contributions,including elastic,electrostatic,and domain wall energy were taken into account in the variational functional of the phase field model.Evolution of the microscopic domain structures of P(VDF-TrFE) polymer film was simulated.Effects of the in-plane residual stress,the film thickness and externa...

  15. Performances of screen-printing silver thick films: Rheology, morphology, mechanical and electronic properties

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jung-Shiun; Liang, Jau-En; Yi, Han-Liou [Department of Chemical Engineering, National Chung Cheng University, Chia Yi 621, Taiwan, ROC (China); Chen, Shu-Hua [China Steel Corporation, Kaohsiung City 806, Taiwan, ROC (China); Hua, Chi-Chung, E-mail: chmcch@ccu.edu.tw [Department of Chemical Engineering, National Chung Cheng University, Chia Yi 621, Taiwan, ROC (China)

    2016-06-15

    Numerous recent applications with inorganic solar cells and energy storage electrodes make use of silver pastes through processes like screen-printing to fabricate fine conductive lines for electron conducting purpose. To date, however, there have been few studies that systematically revealed the properties of the silver paste in relation to the mechanical and electronic performances of screen-printing thick films. In this work, the rheological properties of a series of model silver pastes made of silver powders of varying size (0.9, 1.3, and 1.5 μm) and shape (irregular and spherical) were explored, and the results were systematically correlated with the morphological feature (scanning electron microscopy, SEM) and mechanical (peeling test) and electronic (transmission line method, TLM) performances of screen-printing dried or sintered thick films. We provided evidence of generally intimate correlations between the powder dispersion state in silver pastes—which is shown to be well captured by the rheological protocols employed herein—and the performances of screen-printing thick films. Overall, this study suggests the powder dispersion state and the associated phase behavior of a paste sample can significantly impact not only the morphological and electronic but also mechanical performances of screen-printing thick films, and, in future perspectives, a proper combination of silver powders of different sizes and even shapes could help reconcile quality and stability of an optimum silver paste. - Highlights: • Powder dispersion correlates well with screen-printing thick film performances. • Rheological fingerprints can be utilized to fathom the powder dispersion state. • Good polymer-powder interactions in the paste ensure good powder dispersion. • Time-dependent gel-like viscoelastic features are found with optimum silver pastes. • The size and shape of functional powder affect the dispersion and film performances.

  16. Common electronic origin of superconductivity in (Li,Fe)OHFeSe bulk superconductor and single-layer FeSe/SrTiO3 films.

    Science.gov (United States)

    Zhao, Lin; Liang, Aiji; Yuan, Dongna; Hu, Yong; Liu, Defa; Huang, Jianwei; He, Shaolong; Shen, Bing; Xu, Yu; Liu, Xu; Yu, Li; Liu, Guodong; Zhou, Huaxue; Huang, Yulong; Dong, Xiaoli; Zhou, Fang; Liu, Kai; Lu, Zhongyi; Zhao, Zhongxian; Chen, Chuangtian; Xu, Zuyan; Zhou, X J

    2016-02-08

    The mechanism of high-temperature superconductivity in the iron-based superconductors remains an outstanding issue in condensed matter physics. The electronic structure plays an essential role in dictating superconductivity. Recent revelation of distinct electronic structure and high-temperature superconductivity in the single-layer FeSe/SrTiO3 films provides key information on the role of Fermi surface topology and interface in inducing or enhancing superconductivity. Here we report high-resolution angle-resolved photoemission measurements on the electronic structure and superconducting gap of an FeSe-based superconductor, (Li0.84Fe0.16)OHFe0.98Se, with a Tc at 41 K. We find that this single-phase bulk superconductor shows remarkably similar electronic behaviours to that of the superconducting single-layer FeSe/SrTiO3 films in terms of Fermi surface topology, band structure and the gap symmetry. These observations provide new insights in understanding high-temperature superconductivity in the single-layer FeSe/SrTiO3 films and the mechanism of superconductivity in the bulk iron-based superconductors.

  17. Analysis of water film thickness on contact lens by reflectometry technique

    Science.gov (United States)

    Wang, Michael R.; Lu, Hui; Wang, Jianhua; Shen, Meixiao

    2011-03-01

    We report the use of optical reflectometry technique for evaluation of water film on contact lens. The water film can be measured through the spectral dependent reflectance evaluation, which is carried out by illuminating the contact lens with a white light and collecting the returning light with an optical fiber coupled to a spectrometer. Water film thinning process has been observed on different soft contact lenses and minimum measurable thickness is about 0.85 μm. The measurement is fast and accurate. The water film measurement can be valuable for contact lens design to improve its hydrophilic properties. The technique can be extended for the study of tear film dynamics in an eye.

  18. Temperature and Thickness Effects on Electrical Properties of InP Films Deposited by Spray Pyrolysis

    Institute of Scientific and Technical Information of China (English)

    Rcfik Kayah; Mehmet Ari; Mustafa Oztas; Metin Bedir; Funda Aksoy

    2009-01-01

    InP film samples are prepared by spray pyrolysis technique using aqueous solutions of InCl3 and Na2HPO4, which are atomized with compressed air as carrier gas onto glass substrates at 500 ℃ with different thicknesses of the films. The structural properties of the samples are determined by x-ray diffraction (XRD). It is found that the crystal structure of the InP films is polycrystailine hexagonal. The orientations of all the obtained films are along the c-axis perpendicular to the substrate. The electrical measurements of the samples are obtained by dc four-probe technique on rectangular-shape samples. The effects of temperature on the electrical properties of the InP films are studied in detail.

  19. Thickness and optical constants calculation for chalcogenide-alkali metal Se80Te8(NaCl)12 thin film

    Science.gov (United States)

    Abd-Elrahman, M. I.; Abu-Sehly, A. A.; Bakier, Y. M.; Hafiz, M. M.

    2017-09-01

    Chalcogenide-alkali metal semiconducting thin films of four different thicknesses of Se80Te8(NaCl)12 are deposited from bulk by thermal evaporation technique. The crystallinity of the film improves with increasing of thickness as indicated by the recorded X-ray diffraction patterns. The transmission and reflection spectra are measured in the wavelength range of the incident photons from 250 to 2500 nm. The thickness and optical constants of the films are calculated based on Swanepeol method using the interference patterns appeared in the transmission spectra. It is found that the films have absorption mechanism which is an indirect allowed transition. The effect of the film thickness on the refractive index and the high-frequency dielectric constant are studied. With increasing the film thickness, both the absorption coefficient and high-frequency dielectric constant increase while the single-oscillator energy, optical band gap and extinction coefficient decrease.

  20. An experimental investigation of piezoelectric P(VDF-TrFE) thick film on flexible substrate as energy harvester

    Science.gov (United States)

    Khoon Keat, Chow; Swee Leong, Kok; Kok Tee, Lau

    2017-06-01

    This paper proposes an experimental inves tigation of energy harvester using poly(vinylidene fluoride-trifluoroethylene) or P(VDF-TrFE) thick-film on flexible substrate by using print screen and rod method. Polyester film being used as the substrate where a sandwiched layer of electrode-piezopolymer-electrode thick film is deposited on. The thick-film is then annealed at 100°C and polarized at 100 V for the film with a thickness of about 18µm, being inspected under EDX, FESEM and XRD. The fabricated energy harvester piezoelectric is able to generate a maximum output power of 4.36 µW at an externa l electrical load of 1 kΩ with a maximum peak-to-peak of about 3.0V when an impact free-fall force of 0.2N was applied on the thick-film.

  1. Predicting the Mean Liquid Film Thickness and Profile along the Annular Length of a Uniformly Heated Channel at Dryout

    Directory of Open Access Journals (Sweden)

    V.Y. Agbodemegbe

    2011-03-01

    Full Text Available The objective of this study was to predict the mean liquid film thickness and profile at high shear stress using a mechanistic approach. Knowledge of the liquid film thickness and its variation with two-phase flow parameters is critical for the estimation of safety parameters in the annular flow regime. The mean liquid film thickness and profile were predicted by the PLIFT code designed in Fortran 95 programming language using the PLATO FTN95 compiler. The film thickness was predicted within the annular flow regime for a flow boiling quality ranging from 40 to 80 % at high interfacial shear stress. Results obtained for a laminar liquid film flow were dumped into an excel file when the ratio of the actual predicted film thickness to the critical liquid film thickness lied within the range of 0.9 to unity. The film thickness was observed to decrease towards the exit of the annular regime at high flow boiling qualities and void fractions. The observation confirmed the effect of evaporation in decreasing the film thickness as quality is increased towards the exit of the annular regime.

  2. Characteristics of a thick film ethanol gas sensor made of mechanically treated LaFeO3 powder

    Science.gov (United States)

    Suhendi, Endi; Witra, Hasanah, Lilik; Syarif, Dani Gustaman

    2017-05-01

    In this work, fabrication of LaFeO3 thick film ceramics for ethanol gas sensor made of mechanically treated (milling) powder was studied. The thick films were fabricated using screen printing technique from LaFeO3 powder treated by HEM (High Energy Milling). The films were baked at 800°C for one hour and analyzed using XRD and SEM. Sensitivity of the films was studied by measuring resistance of them at various temperatures in a chamber containing air with and without ethanol gas. Data of XRD showed that the thick film crystalizes in orthorombic structure with space group of Pn*a. SEM data showed that the films consisted of small grains with grain size of about 225 nm. According to the electrical data, the LaFeO3 thick films that produced in this work could be applied as ethanol gas with operating temperature of about 275°C.

  3. Full-field optical thickness profilometry of semitransparent thin films with transmission densitometry

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Jay; Harris, Tequila

    2010-05-20

    A novel bidirectional thickness profilometer based on transmission densitometry was designed to measure the localized thickness of semitransparent films on a dynamic manufacturing line. The densitometer model shows that, for materials with extinction coefficients between 0.3 and 2.9 D/mm, 100-500 {mu}m measurements can be recorded with less than {+-}5% error at more than 10,000 locations in real time. As a demonstration application, the thickness profiles of 75 mmx100 mm regions of polymer electrolyte membrane (PEM) were determined by converting the optical density of the sample to thickness with the Beer-Lambert law. The PEM extinction coefficient was determined to be 1.4 D/mm, with an average thickness error of 4.7%.

  4. Sputtering of thin and intermediately thick films of solid deuterium by keV electrons

    DEFF Research Database (Denmark)

    Svendsen, Winnie Edith; Thestrup Nielsen, Birgitte; Schou, Jørgen

    1995-01-01

    Sputtering of films of solid deuterium by keV electrons was studied in a cryogenic set-up. The sputtering yield shows a minimum yield of about 4 D2/electron for 1.5 and 2 keV electrons at a thickness slightly larger than the average projected range of the electrons. We suggest that the yield around...

  5. Boron film thickness determination to develop a low cost neutron using Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Priscila; Raele, Marcus P.; Yoriyaz, Helio; Siqueira, Paulo de T.D.; Zahn, Guilherme S.; Genezini, Frederico A., E-mail: fredzini@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Neutron measurement is important for safety and security of workers at nuclear facilities. As neutron is an uncharged particle, for its detection is necessary to use a converter material that interacts with the neutron and produce a charged particle, which is easy to detect. One of the converter candidates is natural boron composed by about 20% of Boron-10, which capture a low energy neutron ejecting an energetic alpha particle and a lithium ion. A neutron detector can be developed applying a boron thin film over a silicon photodiode, which is charged particle sensitive. For this reason is important to determine the optimal film thickness. We have used an empirical solution for the boron film thickness evaluation; furthermore we developed, using Monte Carlo method (MCNP6), a model to simulate the alpha particles propagation through the detector. Our goal was to ensure the best production and transference of alpha particles to silicon region. The film thickness ranged between 0 to 5.5 μm, the neutron energy was also varied. The optimal thickness value will be used to develop a prototype of a low cost neutron detector. (author)

  6. Thick-Film and LTCC Passive Components for High-Temperature Electronics

    Directory of Open Access Journals (Sweden)

    A. Dziedzic

    2013-04-01

    Full Text Available At this very moment an increasing interest in the field of high-temperature electronics is observed. This is a result of development in the area of wide-band semiconductors’ engineering but this also generates needs for passives with appropriate characteristics. This paper presents fabrication as well as electrical and stability properties of passive components (resistors, capacitors, inductors made in thick-film or Low-Temperature Co-fired Ceramics (LTCC technologies fulfilling demands of high-temperature electronics. Passives with standard dimensions usually are prepared by screen-printing whereas combination of standard screen-printing with photolithography or laser shaping are recommenced for fabrication of micropassives. Attainment of proper characteristics versus temperature as well as satisfactory long-term high-temperature stability of micropassives is more difficult than for structures with typical dimensions for thick-film and LTCC technologies because of increase of interfacial processes’ importance. However it is shown that proper selection of thick-film inks together with proper deposition method permit to prepare thick-film micropassives (microresistors, air-cored microinductors and interdigital microcapacitors suitable for the temperature range between 150°C and 400°C.

  7. Screen printed PZT/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting

    DEFF Research Database (Denmark)

    Xu, Ruichao; Lei, Anders; Dahl-Petersen, Christian

    2012-01-01

    We present a microelectromechanical system (MEMS) based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. Most piezoelectric energy harvesting devices use a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectri...

  8. Film Thickness Model for Grease-Lubricated Bearing Seals with an Axial Contacting Lip

    NARCIS (Netherlands)

    Baart, P.; van Zoelen, M.T.; Lugt, Pieter Martin

    2013-01-01

    A theoretical model is presented to predict the oil film thickness in an axial sealing contact based on grease properties and operating conditions. It is assumed that a small amount of grease will form an oil reservoir on the rotating part and slowly supply oil to the sealing contact. The oil bleed

  9. Effects of load system dynamics on the film thickness in EHL contacts during start up

    NARCIS (Netherlands)

    Popovici, G.; Venner, Cornelis H.; Lugt, P.M.; Lugt, Pieter Martin

    2004-01-01

    By means of numerical simulations the effects of the loading system on the contact dynamics of an EHL contact during start up have been studied. The work was initiated by experimental results obtained for the start up situation on a ball on disk apparatus in which strong film thickness oscillations

  10. Microstructural Studies of Ni-P Thick Film Resistor Temperature Sensors

    Directory of Open Access Journals (Sweden)

    Barbara Holodnik

    1986-01-01

    Full Text Available Thick Ni-P films have been widely investigated at our Institute. This article tends to visualize by use of various microscopic methods how the growth and sintering of individual conducting grains, results in the formation of nickel dendrites responsible for the metallic character of electrical conduction.

  11. CO responses of sensors based on cerium oxide thick films prepared from clustered spherical nanoparticles.

    Science.gov (United States)

    Izu, Noriya; Matsubara, Ichiro; Itoh, Toshio; Akamatsu, Takafumi; Shin, Woosuck

    2013-03-08

    Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nanoparticles have been reported to have a unique structure: The core consists of a cluster of ceria crystallites several nanometers in size. We compared the characteristics of the sensors based on thick films prepared from core-shell nanoparticles with those of sensors based on thick films prepared from conventionally used precipitated nanoparticles. The sensors prepared from the core-shell nanoparticles exhibited a resistance that was ten times greater than that of the sensors prepared from the precipitated nanoparticles. The response values of the gas sensors based on the core-shell nanoparticles also was higher than that of the sensors based on the precipitated nanoparticles. Finally, improvements in sensor response were also noticed after the addition of Au nanoparticles to the thick films used to fabricate the two types of sensors.

  12. Thickness Dependence of the Quantum Anomalous Hall Effect in Magnetic Topological Insulator Films.

    Science.gov (United States)

    Feng, Xiao; Feng, Yang; Wang, Jing; Ou, Yunbo; Hao, Zhenqi; Liu, Chang; Zhang, Zuocheng; Zhang, Liguo; Lin, Chaojing; Liao, Jian; Li, Yongqing; Wang, Li-Li; Ji, Shuai-Hua; Chen, Xi; Ma, Xucun; Zhang, Shou-Cheng; Wang, Yayu; He, Ke; Xue, Qi-Kun

    2016-08-01

    The evolution of the quantum anomalous Hall effect with the thickness of Cr-doped (Bi,Sb)2 Te3 magnetic topological insulator films is studied, revealing how the effect is caused by the interplay of the surface states, band-bending, and ferromagnetic exchange energy. Homogeneity in ferromagnetism is found to be the key to high-temperature quantum anomalous Hall material.

  13. Investigation of top electrode for PZT thick films based MEMS sensors

    DEFF Research Database (Denmark)

    Hindrichsen, Christian Carstensen; Pedersen, Thomas; Kristiansen, Paw T.;

    2010-01-01

    In this work processing of screen printed piezoelectric PZT thick films on silicon substrates is investigated for use in future MEMS devices. E-beam evaporated Al and Pt are patterned on PZT as a top electrode using a lift-off process with a line width down to 3 mu m. Three test structures are used...

  14. Measurement of oil film thickness and friction force on a guide shoe bearing

    DEFF Research Database (Denmark)

    Vølund, Anders

    2002-01-01

    An experimental program was carried out in order to reveal oil film thickness, and friction force of the guide shoe bearing of a large two stroke marine diesel engine. The experiment was conducted on a full size engine located at the research facility at MAN B&W Diesel A/S. The experiment was con...

  15. Thickness dependence of the L{sub 2,3} branching ratio of Cr thin films

    Energy Technology Data Exchange (ETDEWEB)

    Aksoy, F. [Physics Department, University of Cukurova, 01330 Adana (Turkey); Physics Department, University of Nigde, 51100 Nigde (Turkey); Akguel, G. [Physics Department, University of Cukurova, 01330 Adana (Turkey); Ufuktepe, Y., E-mail: ufuk@cu.edu.t [Physics Department, University of Cukurova, 01330 Adana (Turkey); Nordlund, D. [Stanford Synchrotron Radiation Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2010-10-22

    We report the electronic structure of chromium (Cr) thin films depending on its thickness using two measures, total electron yield (TEY) and transmission yield mode. The Cr L edge X-ray absorption spectroscopy (XAS) spectrum shows strong thickness dependence with broader line widths observed for L{sub 2,3} edge peaks for thinner films. The white line ratio (L{sub 3}/L{sub 2}) was found to be 1.25 from the integrated area under each L{sub 3} and L{sub 2} peak and 1.36 from the ratio of the amplitudes of each L{sub 3} and L{sub 2} peak after the deconvolution. Additionally, we show that full-width at half-maximum (FWHM) at the L{sub 2} and L{sub 3} edges and the branching ratio of Cr change as a function of film thickness and these are discussed in detail. Using L{sub 2,3} resonance intensity variation as a function of film thickness we calculated the electron escape depth and X-ray attenuation length in Cr. Comparing our results with the literature, there was good agreement for the L{sub 3}-L{sub 2} ratio although the detailed shape can show additional solid state and atomic effects.

  16. Blue and green organic light-emitting devices with various film thicknesses for color tuning

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Blue and green organic light-emitting devices with a structure of indium tin oxide (ITO)/N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1 '-biphenyl-4,4'-diamine (NPB)/aluminum(Ⅲ) bis(2-methyl-8-quinolinato)4 -phenylphenolato (BAlq)/tris(8-hydroxyquinolate)-aluminum (Alq3)/Mg:Ag have been fabricated. Blue to green light emission has been achieved with the change of organic film thickness. Based on energy band diagram and charge carrier tunneling theory, it is concluded that the films of different thicknesses play a role as a color-tuning layer and the color-variable electroluminescence (EL) is ascribed to the modulation function within the charge carrier recombination zone. In the case of heterostructure devices with high performance, the observed EL spectra varies significantly with the thickness of organic films, which is resulted from the shift of recombination region site. It has not been hitherto indicated that the devices compose of identical components could be implemented to realize different color emission by changing the film thickness of functional layers.

  17. Effect of thickness-dependent microstructure on the out-of-plane hole mobility in poly(3-hexylthiophene) films.

    Science.gov (United States)

    Huang, Bingyuan; Glynos, Emmanouil; Frieberg, Bradley; Yang, Hengxi; Green, Peter F

    2012-10-24

    Regioregular poly(3-hexylthiophene) (RR-P3HT) is a widely used donor material for bulk heterojunction polymer solar cells. While much is known about the structure and properties of RR-P3HT films, important questions regarding hole mobilities in this material remain unresolved. Measurements of the out-of-plane hole mobilities, μ, of RR-P3HT films have been restricted to films in the thickness regime on the order of micrometers, beyond that generally used in solar cells, where the film thicknesses are typically 100 to 200 nm. Studies of in-plane carrier mobilities have been conducted in thinner films, in the thickness range 100-200 nm. However, the in-plane and out-of-plane hole mobilities in RR-P3HT can be significantly different. We show here that the out-of-plane hole mobilities in neat RR-P3HT films increase by an order of magnitude, from 10(-4) cm(2)/V·s, for a 80 nm thick film, to a value of 10(-3) cm(2)/V·s for films thicker than 700 nm. Through a combination of morphological characterization and simulations, we show that the thickness dependent mobilities are not only associated with the differences between the average morphologies of thick films and thin films, but specifically associated with changes in the local morphology of films as a function of distance from the interfaces.

  18. Electrochemical characterization of YSZ thick films deposited by dip-coating process

    Science.gov (United States)

    Mauvy, F.; Lenormand, P.; Lalanne, C.; Ansart, F.; Bassat, J. M.; Grenier, J. C.; Groupement de Recherches Cnrs "Pacte", Gdr 2985

    Yttria stabilized zirconia (YSZ, 8% Y 2O 3) thick films were coated on dense alumina substrates by a dip-coating process. The suspension was obtained by addition of a polymeric matrix in a stable suspension of commercial YSZ (Tosoh) powders dispersed in an azeotropic mixture MEK-EtOH. The suspension composition was improved by the addition of YSZ Tosoh particles encapsulated by zirconium alkoxide sol containing yttrium nitrate which are the precursors of the 8-YSZ oxide. This optimal formulation allowed preparing, via a dip-coating process, thick films which were, after thermal treatment, homogeneous, dense and crack-free. A specific method was performed to measure the electrical conductivity, i.e. to determine the ionic conductivity of the film: it uses the four-point probe technique combined with ac impedance spectroscopy. The good agreement between the classical two-electrode measurements performed on YSZ pellets and the four-electrode ones performed on YSZ films allows concluding that this method is relevant for characterizing the transport properties of thick films.

  19. Electrochemical characterization of YSZ thick films deposited by dip-coating process

    Energy Technology Data Exchange (ETDEWEB)

    Mauvy, F.; Lalanne, C.; Bassat, J.M.; Grenier, J.C. [Institut de Chimie de la Matiere Condensee de Bordeaux ICMCB - CNRS, Universite Bordeaux 1, 87, av. du Dr. A. Schweitzer, 33 608 Pessac-Cedex (France); Lenormand, P.; Ansart, F. [Centre Interuniversitaire de Recherche et d' Ingenierie et d' Ingenierie des Materiaux, CIRIMAT, Universite Paul Sabatier, Bat. 2R1, 118 route de Narbonne, 31062 Toulouse Cedex (France)

    2007-09-27

    Yttria stabilized zirconia (YSZ, 8% Y{sub 2}O{sub 3}) thick films were coated on dense alumina substrates by a dip-coating process. The suspension was obtained by addition of a polymeric matrix in a stable suspension of commercial YSZ (Tosoh) powders dispersed in an azeotropic mixture MEK-EtOH. The suspension composition was improved by the addition of YSZ Tosoh particles encapsulated by zirconium alkoxide sol containing yttrium nitrate which are the precursors of the 8-YSZ oxide. This optimal formulation allowed preparing, via a dip-coating process, thick films which were, after thermal treatment, homogeneous, dense and crack-free. A specific method was performed to measure the electrical conductivity, i.e. to determine the ionic conductivity of the film: it uses the four-point probe technique combined with ac impedance spectroscopy. The good agreement between the classical two-electrode measurements performed on YSZ pellets and the four-electrode ones performed on YSZ films allows concluding that this method is relevant for characterizing the transport properties of thick films. (author)

  20. Determination of the solvation film thickness of dispersed particles with the method of Einstein viscosity equation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The dispersion of a solid particle in a liquid may lead to the formation of solvation film onthe particle surface, which can strongly increase the repulsive force between particles and thus strongly affect the stability of dispersions. The solvation film thickness, which varies with the variation of the property of suspension particles and solutions, is one of the most important parameters of the solvation film, and is also one of the most difficult parameters that can be measured accurately. In this paper, a method, based on the Einstein viscosity equation of dispersions, for determining the solvation film thickness of particles is developed. This method was tested on two kinds of silica spherical powders (namely M1 and M2) dispersed in ethyl alcohol, in water, and in a water-ethyl alcohol mixture (1:1 by volume) through measuring the relative viscosity of dispersions of the particles as a function of the volume fraction of the dry particles in the dispersion, and of the specific surface area and the density of the particles. The calculated solvation film thicknesses on M1 are 7.48, 18.65 and 23.74 nm in alcohol, water and the water-ethyl alcohol mixture, 12.41, 12.71 and 13.13 nm on M2 in alcohol, water and the water-ethyl alcohol mixture, respectively.

  1. Pad-printed thick-film transducers for high-frequency and high-power applications

    Science.gov (United States)

    Wolny, Wanda W.; Ketterling, Jeffrey A.; Levassort, Franck; Lou-Moeller, Rasmus; Filoux, Erwan; Mamou, Jonathan; Silverman, Ronald H.; Lethiecq, Marc

    2011-03-01

    High-frequency-ultrasound transducers are widely used but are typically based either on planar piezoceramic sections that are lapped down to smaller thicknesses or on piezopolymers that may be deformed into more complex geometries. Piezoceramics then require dicing to obtain arrays or can be fractured into spherical geometries to achieve focusing. Piezopolymers are not as efficient for very small element sizes and are normally available only in discrete thicknesses. Thick-film (TF) transducers provide a means of overcoming these limits because the piezoelectric film is deposited with the required thickness, size and geometry, thus avoiding any subsequent machining. Thick-film transducers offer the potential of a wide range of geometries such as single-elements and annular or linear arrays. Here, a single-element focused transducer was developed using a piezoceramic composition adapted to high-power operation which is commonly used at standard MHz frequencies. After fabrication, the transducer was characterized. Using specific transmit-receive electronics and a water tank adapted to high-frequency devices, the transducer was excited using a short pulse to evaluate its bandwidth and imaging capabilities. Finally, it was excited by a one-period sine wave using several power levels to evaluate its capacity to produce high-intensity focused ultrasound at frequencies over 20 MHz.

  2. Correlation between active layer thickness and ambient gas stability in IGZO thin-film transistors

    Science.gov (United States)

    Gao, Xu; Lin, Meng-Fang; Mao, Bao-Hua; Shimizu, Maki; Mitoma, Nobuhiko; Kizu, Takio; Ou-Yang, Wei; Nabatame, Toshihide; Liu, Zhi; Tsukagoshi, Kazuhito; Wang, Sui-Dong

    2017-01-01

    Decreasing the active layer thickness has been recently reported as an alternative way to achieve fully depleted oxide thin-film transistors for the realization of low-voltage operations. However, the correlation between the active layer thickness and device resistivity to environmental changes is still unclear, which is important for the optimized design of oxide thin-film transistors. In this work, the ambient gas stability of IGZO thin-film transistors is found to be strongly correlated to the IGZO thickness. The TFT with the thinnest IGZO layer shows the highest intrinsic electron mobility in a vacuum, which is greatly reduced after exposure to O2/air. The device with a thick IGZO layer shows similar electron mobility in O2/air, whereas the mobility variation measured in the vacuum is absent. The thickness dependent ambient gas stability is attributed to a high-mobility region in the IGZO surface vicinity with less sputtering-induced damage, which will become electron depleted in O2/air due to the electron transfer to adsorbed gas molecules. The O2 adsorption and deduced IGZO surface band bending is demonstrated by the ambient-pressure x-ray photoemission spectroscopy results.

  3. Field-Assisted and Thermionic Contributions to Conductance in SnO Thick-Films

    Directory of Open Access Journals (Sweden)

    C. Malagù

    2009-01-01

    Full Text Available A deep analysis of conductance in nanostructured SnO2 thick films has been performed. A model for field-assisted thermionic barrier crossing is being proposed to explain the film conductivity. The model has been applied to explain the behavior of resistance in vacuum of two sets of nanostructured thick-films with grains having two well-distinct characteristic radii (=25 nm and =125 nm. In the first case the grain radius is shorter than the depletion region width, a limit at which overlapping of barriers takes place, and in the second case it is longer. The behavior of resistance in the presence of dry air has been explained through the mechanism of barrier modulation through gas chemisorption.

  4. Experimental Comparison of the Behavior between Base Oil and Grease Starvation Based on Inlet Film Thickness

    Directory of Open Access Journals (Sweden)

    D. Kostal

    2017-03-01

    Full Text Available This paper deals with the experimental study of an elastohydrodynamic contact under conditions of insufficient lubricant supply. Starvation level of this type of the contact may be experimentally determined based on the position of the meniscus, but this way can't determine all levels of starvation. Consequent development in the field of tribology achieved theoretical model that can determine all levels of starvation by dependency on the thickness of the lubricant film entering the contact, but it is difficult for experimental verification. The main goal of this work is an experimental study and description of the behavior of the elastohydrodynamic contact with controlled thickness of the lubricant film at the contact input. Contact was lubricated by the base oil and the grease and compared. Results were surprising because the only differences between oil and grease were observed for more viscous lubricants at thicker film layer entering to the contact.

  5. Method for rapid, controllable growth and thickness, of epitaxial silicon films

    Science.gov (United States)

    Wang, Qi; Stradins, Paul; Teplin, Charles; Branz, Howard M.

    2009-10-13

    A method of producing epitaxial silicon films on a c-Si wafer substrate using hot wire chemical vapor deposition by controlling the rate of silicon deposition in a temperature range that spans the transition from a monohydride to a hydrogen free silicon surface in a vacuum, to obtain phase-pure epitaxial silicon film of increased thickness is disclosed. The method includes placing a c-Si substrate in a HWCVD reactor chamber. The method also includes supplying a gas containing silicon at a sufficient rate into the reaction chamber to interact with the substrate to deposit a layer containing silicon thereon at a predefined growth rate to obtain phase-pure epitaxial silicon film of increased thickness.

  6. Cellular-foam polypropylene ferroelectrets with increased film thickness and reduced resonance frequency

    Science.gov (United States)

    Sborikas, Martynas; Wegener, Michael

    2013-12-01

    Ferroelectrets are piezoelectric materials suitable for acoustic applications such as airborne ultrasonic transducers. Typical ferroelectrets exhibit resonance frequencies in the high kHz to low MHz range. In order to decrease the transducer resonance frequencies to the low kHz range, processes such as gas-diffusion expansion and electric charging were adjusted to cellular films which are initially twice as thick as in earlier studies. The demonstrated film expansion and electric charging lead to mechanically soft cellular structures which show high piezoelectric activities with coefficients up to 130 pC/N. Due to the simultaneously increased film thicknesses, the resonance frequencies are lowered down to about 233 kHz.

  7. Hard X-rays for processing hybrid organic-inorganic thick films.

    Science.gov (United States)

    Jiang, Yu; Carboni, Davide; Pinna, Alessandra; Marmiroli, Benedetta; Malfatti, Luca; Innocenzi, Plinio

    2016-01-01

    Hard X-rays, deriving from a synchrotron light source, have been used as an effective tool for processing hybrid organic-inorganic films and thick coatings up to several micrometres. These coatings could be directly modified, in terms of composition and properties, by controlled exposure to X-rays. The physico-chemical properties of the coatings, such as hardness, refractive index and fluorescence, can be properly tuned using the interaction of hard X-rays with the sol-gel hybrid films. The changes in the microstructure have been correlated especially with the modification of the optical and the mechanical properties. A relationship between the degradation rate of the organic groups and the rise of fluorescence from the hybrid material has been observed; nanoindentation analysis of the coatings as a function of the X-ray doses has shown a not linear dependence between thickness and film hardness.

  8. Analysis of variance on thickness and electrical conductivity measurements of carbon nanotube thin films

    Science.gov (United States)

    Li, Min-Yang; Yang, Mingchia; Vargas, Emily; Neff, Kyle; Vanli, Arda; Liang, Richard

    2016-09-01

    One of the major challenges towards controlling the transfer of electrical and mechanical properties of nanotubes into nanocomposites is the lack of adequate measurement systems to quantify the variations in bulk properties while the nanotubes were used as the reinforcement material. In this study, we conducted one-way analysis of variance (ANOVA) on thickness and conductivity measurements. By analyzing the data collected from both experienced and inexperienced operators, we found some operation details users might overlook that resulted in variations, since conductivity measurements of CNT thin films are very sensitive to thickness measurements. In addition, we demonstrated how issues in measurements damaged samples and limited the number of replications resulting in large variations in the electrical conductivity measurement results. Based on this study, we proposed a faster, more reliable approach to measure the thickness of CNT thin films that operators can follow to make these measurement processes less dependent on operator skills.

  9. Real-time dielectric-film thickness measurement system for plasma processing chamber wall monitoring.

    Science.gov (United States)

    Kim, Jin-Yong; Chung, Chin-Wook

    2015-12-01

    An in-situ real-time processing chamber wall monitoring system was developed. In order to measure the thickness of the dielectric film, two frequencies of small sinusoidal voltage (∼1 V) signals were applied to an electrically floated planar type probe, which is positioned at chamber wall surface, and the amplitudes of the currents and the phase differences between the voltage and current were measured. By using an equivalent sheath circuit model including a sheath capacitance, the dielectric thickness can be obtained. Experiments were performed in various plasma condition, and reliable dielectric film thickness was obtained regardless of the plasma properties. In addition, availability in commercial chamber for plasma enhanced chemical vapor deposition was verified. This study is expected to contribute to the control of etching and deposition processes and optimization of periodic maintenance in semiconductor manufacturing process.

  10. Film thickness effect on the performance of small molecular solar cell

    Institute of Scientific and Technical Information of China (English)

    LIN Hui; YU Jun-sheng; HUANG Jiang; JIANG Ya-dong

    2008-01-01

    An efficient organic photovoltaic (OPV) cell with an indium-tin-oxide/CuPc/C60/Ag structure has been investigated by changing the film thickness of organic layers. A high open-circuit voltage (Voc) of 0.5 V, a short-circuit current density (JSC) of 5.81 mA/cm2, and a high power conversion efficiency (ηp) of 1.2% were achieved at an optimum film thickness. The results demonstrate that material thickness is an important factor to cell optimization, especially for maximizing the absorption rate as well as reducing the cell resistance. Experimental results also indicate that the power conversion efficiency increases from 1.2% to 1.54% as a BCP exciton blocking layer of 10 nm is introduced.

  11. Full spin switch effect for the superconducting current in a superconductor/ferromagnet thin film heterostructure

    Science.gov (United States)

    Leksin, P. V.; Garif'yanov, N. N.; Garifullin, I. A.; Schumann, J.; Vinzelberg, H.; Kataev, V.; Klingeler, R.; Schmidt, O. G.; Büchner, B.

    2010-09-01

    Using the spin switch design F1/F2/S theoretically proposed by Oh et al., [Appl. Phys. Lett. 71, 2376 (1997)], that comprises a ferromagnetic bilayer as a ferromagnetic component, and an ordinary superconductor as the second interface component, we have realized a full spin switch effect for the superconducting current. An experimental realization of this spin switch construction was achieved for the CoOx/Fe1/Cu/Fe2/In multilayer.

  12. Thickness of Residual Wetting Film in Liquid-Liquid Displacement in Capillary Channels

    Science.gov (United States)

    Beresnev, I. A.; Gaul, W.; Vigil, D.

    2010-12-01

    Core-annular flow is common in nature, representing, for example, how streams of oil, surrounded by water, move in petroleum reservoirs. Oil, typically a non-wetting fluid, tends to occupy the middle (core) part of a channel, while water forms a surrounding wall-wetting film. What is the thickness of this wetting film? Understanding this question may determine the ultimate oil recovery. A classic theory has been in existence for nearly 50 years offering a solution, although in a controversial manner, for moving gas bubbles. On the other hand, an acceptable, experimentally verified theory for a body of one liquid flowing in another has not been available. We develop a hydrodynamic, testable theory providing an explicit relationship between the thickness of the wetting film and fluid properties for a blob of one fluid moving in another, with neither phase being gas. In its relationship to the capillary number Ca, the thickness of the film is predicted to be proportional to Ca2 at lower Ca and to level off at a constant value of about 20 % the channel radius at higher Ca. The thickness of the film is deduced to be approximately unaffected by the viscosity ratio of the fluids. We have conducted our own laboratory experiments and compiled experimental data from other studies, all of which are mutually consistent and confirm the salient features of the theory. At the same time, the classic law, originally deduced for films surrounding moving gas bubbles but often believed to hold for liquids as well, fails to explain the observations.

  13. Novel method for the measurement of liquid film thickness during fuel spray impingement on surfaces.

    Science.gov (United States)

    Henkel, S; Beyrau, F; Hardalupas, Y; Taylor, A M K P

    2016-02-01

    This paper describes the development and application of a novel optical technique for the measurement of liquid film thickness formed on surfaces during the impingement of automotive fuel sprays. The technique makes use of the change of the light scattering characteristics of a metal surface with known roughness, when liquid is deposited. Important advantages of the technique over previously established methods are the ability to measure the time-dependent spatial distribution of the liquid film without a need to add a fluorescent tracer to the liquid, while the measurement principle is not influenced by changes of the pressure and temperature of the liquid or the surrounding gas phase. Also, there is no need for non-fluorescing surrogate fuels. However, an in situ calibration of the dependence of signal intensity on liquid film thickness is required. The developed method can be applied to measure the time-dependent and two-dimensional distribution of the liquid fuel film thickness on the piston or the liner of gasoline direct injection (GDI) engines. The applicability of this technique was evaluated with impinging sprays of several linear alkanes and alcohols with different thermo-physical properties. The surface temperature of the impingement plate was controlled to simulate the range of piston surface temperatures inside a GDI engine. Two sets of liquid film thickness measurements were obtained. During the first set, the surface temperature of the plate was kept constant, while the spray of different fuels interacted with the surface. In the second set, the plate temperature was adjusted to match the boiling temperature of each fuel. In this way, the influence of the surface temperature on the liquid film created by the spray of different fuels and their evaporation characteristics could be demonstrated.

  14. On the Correlation of Specific Film Thickness and Gear Pitting Life

    Science.gov (United States)

    Krantz, Timothy L.

    2015-01-01

    The effect of the lubrication regime on gear performance has been recognized, qualitatively, for decades. Often the lubrication regime is characterized by the specific film thickness defined as the ratio of lubricant film thickness to the composite surface roughness. It can be difficult to combine results of studies to create a cohesive and comprehensive dataset. In this work gear surface fatigue lives for a wide range of specific film values were studied using tests done with common rigs, speeds, lubricant temperatures, and test procedures. This study includes previously reported data, results of an additional 50 tests, and detailed information from lab notes and tested gears. The dataset comprised 258 tests covering specific film values (0.47 to 5.2). The experimentally determined surface fatigue lives, quantified as 10-percent life estimates, ranged from 8.7 to 86.8 million cycles. The trend is one of increasing life for increasing specific film. The trend is nonlinear. The observed trends were found to be in good agreement with data and recommended practice for gears and bearings. The results obtained will perhaps allow for the specific film parameter to be used with more confidence and precision to assess gear surface fatigue for purpose of design, rating, and technology development.

  15. Deposition of thick Co-rich CoPtP films with high energy product for magnetic microelectromechanical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, Santosh [Microsystems Center, Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland); Roy, Saibal, E-mail: saibal.roy@tyndall.i [Microsystems Center, Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland)

    2010-05-15

    We report the development of Co-rich CoPtP films of thicknesses up to 82 mum for use in magnetic MEMS applications. These films have been deposited using a combination of pulse-reverse plating with the addition of stress-relieving additives to the bath. The films were electroplated on sputtered Cu/Ti seed layer on silicon with an optimized thickness of 100/20 nm. The composition, crystalline structure, grain size and magnetic properties of the CoPtP films of varying thickness are compared and analyzed. The 3-mum-thick CoPtP film showed a columnar structure and strong perpendicular anisotropy. This film shows a perpendicular coercivity of 2150 Oe, a remanence of 0.564 T and a maximum energy product of 20 kJ/m{sup 3}. As the thickness of the plated film is increased, there is a gradual decrease in the coercivity and anisotropy. The 82-mum-thick film had a perpendicular coercivity of 1150 Oe and a remanence of 0.35 T. While there is a drop in coercivity and anisotropy, the remanence and maximum energy product remain constant for film thicknesses greater than 13 mum. The reason for the drop in coercivity and the near-constant remanence for thicker CoPtP films is discussed here. The coercivity of the thick Co-rich CoPtP film reported in this work is similar to those reported in the literature; the values of remanence, maximum energy product and saturation magnetization are the highest of all the thick (>50 mum) electroplated films in the literature.

  16. Thickness dependencies of structural and magnetic properties of cubic and tetragonal Heusler alloy bilayer films

    Science.gov (United States)

    Ranjbar, R.; Suzuki, K. Z.; Sugihara, A.; Ando, Y.; Miyazaki, T.; Mizukami, S.

    2017-07-01

    The thickness dependencies of the structural and magnetic properties for bilayers of cubic Co-based Heusler alloys (CCHAs: Co2FeAl (CFA), Co2FeSi (CFS), Co2MnAl (CMA), and Co2MnSi (CMS)) and D022-MnGa were investigated. Epitaxy of the B2 structure of CCHAs on a MnGa film was achieved; the smallest thickness with the B2 structure was found for 3-nm-thick CMS and CFS. The interfacial exchange coupling (Jex) was antiferromagnetic (AFM) for all of the CCHAs/MnGa bilayers except for unannealed CFA/MnGa samples. A critical thickness (tcrit) at which perpendicular magnetization appears of approximately 4-10 nm for the CMA/MnGa and CMS/MnGa bilayers was observed, whereas this thickness was 1-3 nm for the CFA/MnGa and CFS/MnGa films. The critical thickness for different CCHAs materials is discussed in terms of saturation magnetization (Ms) and the Jex .

  17. Structural, morphological, electrical, and optical properties of silver thin films of varying thickness deposited on cupric oxide

    Science.gov (United States)

    Hajakbari, Fatemeh; Shafieinejad, Farzaneh

    2016-03-01

    In this investigation, silver (Ag) films of varying thickness (25-100 nm) were grown on cupric oxide (CuO) on silicon and quartz. The CuO preparation was carried out by the thermal oxidation annealing of copper (Cu) thin films deposited by DC magnetron sputtering. The physical properties of the prepared films were studied by different techniques. Rutherford backscattering spectroscopy (RBS) analysis indicated that the Ag film thickness was about 25-100 nm. X-ray diffraction (XRD) results showed that by increasing Ag thickness, the film crystallinity was improved. Also, atomic force microscopy (AFM) and scanning electron microscopy (SEM) results demonstrated that the surface morphology and the grain size were affected by the Ag film thickness. Furthermore, the electrical resistivity of films determined by four-point probe measurements versus the Ag film thickness was discussed. A reduction in the optical band gap energy of CuO is observed from 1.51 to 1.42 eV with an increase in Ag film thickness to 40 nm in Ag/CuO films.

  18. Fabrication and characterization of micromachined high-frequency tonpilz transducers derived by PZT thick films.

    Science.gov (United States)

    Zhou, Qifa; Cannata, Jonathan M; Meyer, Richard J; van Tol, David J; Tadigadapa, Srinivas; Hughes, W Jack; Shung, K Kirk; Trolier-McKinstry, Susan

    2005-03-01

    Miniaturized tonpilz transducers are potentially useful for ultrasonic imaging in the 10 to 100 MHz frequency range due to their higher efficiency and output capabilities. In this work, 4 to 10-microm thick piezoelectric thin films were used as the active element in the construction of miniaturized tonpilz structures. The tonpilz stack consisted of silver/lead zirconate titanate (PZT)/lanthanum nickelate (LaNiO3)/silicon on insulator (SOI) substrates. First, conductive LaNiO3 thin films, approximately 300 nm in thickness, were grown on SOI substrates by a metalorganic decomposition (MOD) method. The room temperature resistivity of the LaNiO3 was 6.5 x 10(-6) omega x m. Randomly oriented PZT (52/48) films up to 7-microm thick were then deposited using a sol-gel process on the LaNiO3-coated SOI substrates. The PZT films with LaNiO3 bottom electrodes showed good dielectric and ferroelectric properties. The relative dielectric permittivity (at 1 kHz) was about 1030. The remanent polarization of PZT films was larger than 26 microC/cm2. The effective transverse piezoelectric e31,f coefficient of PZT thick films was about -6.5 C/m2 when poled at -75 kV/cm for 15 minutes at room temperature. Enhanced piezoelectric properties were obtained on poling the PZT films at higher temperatures. A silver layer about 40-microm thick was prepared by silver powder dispersed in epoxy and deposited onto the PZT film to form the tail mass of the tonpilz structure. The top layers of this wafer were subsequently diced with a saw, and the structure was bonded to a second wafer. The original silicon carrier wafer was polished and etched using a Xenon difluoride (XeF2) etching system. The resulting structures showed good piezoelectric activity. This process flow should enable integration of the piezoelectric elements with drive/receive electronics.

  19. An experimental evaluation of the Hamrock and Dowson minimum film thickness equation for fully flooded EHD point contacts

    Science.gov (United States)

    Koye, K. A.; Winer, W. O.

    1980-08-01

    Fifty-seven measurements of the minimum lubricant film separating the elastohydrodynamically lubricated point contact of a steel crowned roller and a flat sapphire disk were made by an optical interferometry technique. The data collected were used to evaluate the Hamrock and Dowson minimum EHD film thickness model over a practical range of contact ellipticity ratio where the major axis of the contact ellipse is aligned both parallel and perpendicular to the direction of motion. A statistical analysis of the measured film thickness data showed that on the average the experimental data averaged 30 percent greater film thickness than the Hamrock and Dowson model predicts.

  20. Screen printed Y and Bi-based superconductors

    Science.gov (United States)

    Haertling, Gene H.; Hsi, Chi-Shiung

    1992-01-01

    High T(sub c) superconducting thick film was prepared by screen printing process. Y-based (YBa2Cu3O(7 - x)) superconducting thick films were printed on 211/Al2O3, SNT/Al2O3, and YSZ substrates. Because of poor adhesion of the superconducting thick films to 211/Al2O3 and SNT/Al2O3 substrates, relatively low T(sub c) and J(sub c) values were obtained from the films printed on these substrates. Critical temperatures of YBa2Cu3O(7 - x) thick films deposited on 211/Al2O3 and SNT/Al2O3 substrates were about 80 K. The critical current densities of these films were less than 2 A/cm(exp 2). Higher T(sub c) and J(sub c) films were printed on the YSZ substrates; T(sub c) = 86.4 K and J(sub c) = 50.4 A/cm(exp 2). Multiple lead samples were also prepared on the YSZ substrates. These showed lower T(sub c) and J(sub c) values than plain samples. The heat treatment conditions of the multiple lead samples are still under investigation. Bi-based superconductor thick films have been obtained so far. Improving the superconducting properties of the BSCCO screen printed thick films will be emphasized in future work.

  1. Indium-Nitrogen Codoped Zinc Oxide Thin Film Deposited by Ultrasonic Spray Pyrolysis on n-(111 Si Substrate: The Effect of Film Thickness

    Directory of Open Access Journals (Sweden)

    Cheng-Chang Yu

    2014-01-01

    Full Text Available Indium-nitrogen codoped zinc oxide (INZO thin films were fabricated by spray pyrolysis deposition technique on n-(111 Si substrate with different film thicknesses at 450°C using a precursor containing zinc acetate, ammonium acetate, and indium nitrate with 1 : 3 : 0.05 at.% concentration. The morphology and structure studies were carried out by scanning electron microscopy (SEM and X-ray diffraction (XRD. The grain size of the films increased when increasing the film thickness. From XRD spectra, polycrystalline ZnO structure can be observed and the preferred orientation behavior varied from (002 to (101 as the film thickness increased. The concentration and mobility were investigated by Hall effect measurement. the p-type films with a hole mobility around 3 cm2V−1s−1 and hole concentration around 3×1019 cm−3 can be achieved with film thickness less than 385 nm. The n-type conduction with concentration 1×1020 cm−3 is observed for film with thickness 1089 nm. The defect states were characterized by photoluminescence. With temperature-dependent conductivity analysis, acceptor state with activation energy 0.139 eV dominate the p type conduction for thin INZO film. And the Zn-related shallow donors with activation energy 0.029 eV dominate the n-type conduction for the thick INZO film.

  2. Thickness Dispersion of Surface Plasmon of Ag Nano-thin Films: Determination by Ellipsometry Iterated with Transmittance Method

    Science.gov (United States)

    Gong, Junbo; Dai, Rucheng; Wang, Zhongping; Zhang, Zengming

    2015-03-01

    Effective optical constants of Ag thin films are precisely determined with effective thickness simultaneously by using an ellipsometry iterated with transmittance method. Unlike the bulk optical constants in Palik's database the effective optical constants of ultrathin Ag films are found to strongly depend on the thickness. According to the optical data two branches of thickness dispersion of surface plasmon energy are derived and agreed with theoretical predication. The thickness dispersion of bulk plasmon is also observed. The influence of substrate on surface plasmon is verified for the first time by using ellipsometry. The thickness dependent effective energy loss function is thus obtained based on this optical method for Ag ultrathin films. This method is also applicable to other ultrathin films and can be used to establish an effective optical database for ultrathin films.

  3. Thickness dependence of the magnetic properties of high-coercive Pr-Fe-B thin films with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, F. [Shenyang National Laboratory for Materials Science, Institute of Metal Research and International Centre for Materials Physics, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang Liaoning 110016 (China); Liu, W. [Shenyang National Laboratory for Materials Science, Institute of Metal Research and International Centre for Materials Physics, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang Liaoning 110016 (China)], E-mail: wliu@imr.ac.cn; Cui, W.B.; Feng, J.N.; Zhang, Y.Q.; Zhang, Z.D [Shenyang National Laboratory for Materials Science, Institute of Metal Research and International Centre for Materials Physics, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang Liaoning 110016 (China)

    2008-10-01

    The magnetic properties of Pr-Fe-B films with perpendicular magnetic anisotropy have been studied as a function of thickness varying from 10 to 1200 nm. The crucial thickness for forming the Pr{sub 2}Fe{sub 14}B phase is estimated to be about 25 nm in our study, and the perpendicular anisotropy shows a trend to vanish for thick films. The coercivity of the films initially increases with increasing film thickness, gradually reaching a value which is near the value for bulk material. The magnetic domain size increases with increasing thickness. The surface morphology, the roughness and the domain structure of the films have been investigated by means of atomic-force microscopy and magnetic-force microscopy.

  4. Quartz Microbalance Study of 400-angstrom Thick Films near the lambda Point

    Science.gov (United States)

    Chan, Moses H. W.

    2003-01-01

    In a recent measurement we observed the thinning of an adsorbed helium film induced by the confinement of critical fluctuations a few millikelvin below the lambda point. A capacitor set-up was used to measure this Casimir effect. In this poster we will present our measurement of an adsorbed helium film of 400 angstroms near the lambda point with a quartz microbalance. For films this thick, we must take into account the non-linear dynamics of the shear waves in the fluid. In spite of the added complications, we were able to confirm the thinning of the film due to the Casimir effect and the onset of the superfluid transition. In addition, we observe a sharp anomaly at the bulk lambda point, most likely related to critical dissipation of the first sound. This work is carried out in collaboration with Rafael Garcia, Stephen Jordon and John Lazzaretti. This work is funded by NASA's Office of Biological and Physical Research under grant.

  5. Alignment of muscle precursor cells on the vertical edges of thick carbon nanotube films.

    Science.gov (United States)

    Holt, Ian; Gestmann, Ingo; Wright, Andrew C

    2013-10-01

    The development of scaffolds and templates is an essential aspect of tissue engineering. We show that thick (>0.5 mm) vertically aligned carbon nanotube films, made by chemical vapour deposition, can be used as biocompatible substrates for the directional alignment of mouse muscle cells where the cells grow on the exposed sides of the films. Ultra high resolution scanning electron microscopy reveals that the films themselves consist mostly of small diameter (10 nm) multi-wall carbon nanotubes of wavy morphology with some single wall carbon nanotubes. Our findings show that for this alignment to occur the nanotubes must be in pristine condition. Mechanical wiping of the films to create directional alignment is detrimental to directional bioactivity. Larger areas for study have been formed from a composite of multiply stacked narrow strips of nanotubes wipe-transferred onto elastomer supports. These composite substrates appear to show a useful degree of alignment of the cells.

  6. Effects of ITO precursor thickness on transparent conductive Al doped ZnO film for solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dong-Won; Kuk, Seung-Hee; Han, Min-Koo [School of Electrical Engineering, Seoul National University, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Ji, Kwang-Sun; Lee, Heon-Min [LG Electronics, 16 Woomyeon-Dong Seocho-Gu, Seoul (Korea, Republic of)

    2011-01-15

    Al doped ZnO (AZO) film was continuously deposited on ITO precursor on glass substrate by d.c. magnetron sputtering. The thickness of ITO was varied from 30 to 120 nm in order to investigate the effect of ITO thickness on crystallinity of AZO film. X-ray diffraction measurement shows that AZO film grown on ITO has an enhanced (0 0 2) preferred orientation as the ITO thickness was increased. The crystalline structure improvement of AZO film with an increase of ITO precursor thickness is due to the near-epitaxial growth of AZO on ITO precursor. As the ITO thickness was increased, mobility of AZO film by the Hall measurement was significantly increased from 5.4 cm{sup 2}/V s (no ITO) to 23.6 cm{sup 2}/V s (ITO 120 nm), and resistivity was about 81.7% improved from 1.99 x 10{sup -3} to 3.63 x 10{sup -4} {omega} cm. The AZO films with ITO revealed excellent average transmission of visible (90.0%) and NIR (89.6%) regions, whereas those of AZO film without ITO were 82.1% and 88.1%, respectively. The haze values of AZO film with ITO of 90 and 120 nm are similar or higher than those of AZO film without ITO. The surface textured AZO film with ITO precursor is promising for optoelectronic applications such as the front TCO of thin film solar cells. (author)

  7. Thickness-dependent piezoelectric behaviour and dielectric properties of lanthanum modified BiFeO3 thin films

    Directory of Open Access Journals (Sweden)

    Glenda Biasotto

    2011-03-01

    Full Text Available Bi0.85La0.15FeO3 (BLFO thin films were deposited on Pt(111/Ti/SiO2 /Si substrates by the soft chemical method. Films with thicknesses ranging from 140 to 280 nm were grown on platinum coated silicon substrates at 500°C for 2 hours. The X-ray diffraction analysis of BLFO films evidenced a hexagonal structure over the entire thickness range investigated. The grain size of the film changes as the number of the layers increases, indicating thickness dependence. It is found that the piezoelectric response is strongly influenced by the film thickness. It is shown that the properties of BiFeO3 thin films, such as lattice parameter, dielectric permittivity, piezoeletric coefficient etc., are functions of misfit strains.

  8. The relationship between refractive index-energy gap and the film thickness effect on the characteristic parameters of CdSe thin films

    Science.gov (United States)

    Akaltun, Yunus; Yıldırım, M. Ali; Ateş, Aytunç; Yıldırım, Muhammet

    2011-05-01

    CdSe thin films were deposited on glass substrates using Successive Ionic Layer Adsorption and Reaction (SILAR) method at room temperature and ambient pressure. The relationship between refractive index and energy bandgap was investigated. The film thickness effect on the structural, morphological, optical and electrical properties of CdSe thin films was investigated. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies showed that all the films exhibit polycrystalline nature with hexagonal structure and are covered well with glass substrates. The crystalline and surface properties of the films improved with increasing film thickness. The optical absorption studies revealed that the films are found to be a direct allowed transition. The energy bandgap values were changed from 1.93 to 1.87 eV depending on the film thickness. The electron effective mass (m e*/m o), refractive index ( n), optical static and high frequency dielectric constant (ɛ o, ɛ ∞) values were calculated by using the energy bandgap values as a function of the film thickness. The resistivity of the films changed between 10 6 and 10 2 Ω-cm with increasing film thickness at room temperature.

  9. Thickness-dependent quantum oscillations in Cd3As2 thin films

    Science.gov (United States)

    Cheng, Peihong; Zhang, Cheng; Liu, Yanwen; Yuan, Xiang; Song, Fengqi; Sun, Qingqing; Zhou, Peng; Zhang, David Wei; Xiu, Faxian

    2016-08-01

    Cd3As2 is a new kind of three-dimensional (3D) Dirac semimetal with extraordinary carrier mobility, which can be viewed as ‘3D graphene’. Theory predicts that Cd3As2 can be driven into a quantum spin Hall insulator with a sizeable band gap by reducing dimensionality. In this letter, we report the systematic growth of undoped Cd3As2 thin films with the thickness of 50 ˜ 900 nm by molecular beam epitaxy. The magneto-transport study on these single-crystalline films shows a high mobility in the range of 3.8 ˜ 9.1 × 103 cm2 · V-1 · s-1 and a relative low electron concentration of 1 ˜ 8 × 1017 cm-3. Significantly, a thickness-induced semimetal-to-semiconductor transition was observed. In contrast with what is expected in the bulk counterpart, the 50 nm-thick Cd3As2 film exhibits semiconducting characteristics, witnessing an emerged bandgap opening when the dimensionality is reduced. Finally, the analyses on the temperature- and angular-dependence of magneto-resistance and Shubnikov-de Hass oscillations reveal a non-trivial to trivial Berry’s phase transition that is in connection with the reduced dimensionality. Our results demonstrate that the Cd3As2 thin films with unique electronic structure and high mobility hold promise for Dirac semimetal device applications.

  10. The damping model for sea waves covered by oil films of a finite thickness

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yanmin; ZHANG Jie; WANG Yunhua; MENG Junmin; ZHANG Xi

    2015-01-01

    In combination with a wave action balance equation, a damping model for sea waves covered by oil films of a finite thickness is proposed. The damping model is not only related to the physical parameters of the oil film, but also related to environment parameters. Meanwhile, the parametric analyses have been also conducted to understand the sensitivity of the damping model to these parameters. And numerical simulations demonstrate that a kinematic viscosity, a surface/interfacial elasticity, a thickness, and a fractional filling factor cause more significant effects on a damping ratio than the other physical parameters of the oil film. From the simulation it is also found that the influences induced by a wind speed and a wind direction are also remarkable. On the other hand, for a thick emulsified oil film, the damping effect on the radar signal induced by the reduction of an effective dielectric constant should also be taken into account. The simulated results are compared with the damping ratio evaluated by the 15 ENVISAT ASAR images acquired during the Gulf of Mexico oil spill accident.

  11. Perfect light trapping in nanoscale thickness semiconductor films with resonant back reflector and spectrum-splitting structures

    CERN Document Server

    Liu, Jiang-Tao; Yang, Wen; Li, Jun

    2014-01-01

    The optical absorption of nanoscale thickness semiconductor films on top of light-trapping structures based on optical interference effects combined with spectrum-splitting structures is theoretically investigated. Nearly perfect absorption over a broad spectrum range can be achieved in $<100$ nm thick films on top of one-dimensional photonic crystal or metal films. This phenomenon can be attributed to interference induced photonic localization, which enhances the absorption and reduces the reflection of the films. Perfect solar absorption and low carrier thermalization loss can be achieved when the light-trapping structures with wedge-shaped spacer layer or semiconductor films are combined with spectrum-splitting structures.

  12. The influence of the film thickness of nanostructured alpha-Fe2O3 on water photooxidation.

    Science.gov (United States)

    Souza, Flavio Leandro; Lopes, Kirian Pimenta; Longo, Elson; Leite, Edson Roberto

    2009-02-28

    The present work shows the influence of the film thickness in the optical and photoelectrochemical properties of nanostructured alpha-Fe(2)O(3) thin film. We found that the film thickness has a strong influence on the optical absorption and the results here reported can help in the design of nanostructured alpha-Fe(2)O(3) with superior performance for water photo-oxidation. The results show that the optical property of the hematite film is affected by the film thickness, probably due to the stress induced by the strong interaction between film and substrate. This stress generates defects in the crystal lattice of the hematite film, increasing the (e(-))-(h(+)) recombination process.

  13. Thickness determination of large-area films of yttria-stabilized zirconia produced by pulsed laser deposition

    DEFF Research Database (Denmark)

    Pryds, N.; Christensen, Bo Toftmann; Bilde-Sørensen, Jørgen;

    2006-01-01

    Films of yuria-stabilized zirconia (YSZ) on a polished silicon substrate of diameter up to 125 mm have been produced in a large-area pulsed laser deposition (PLD) setup under typical PLD conditions. The film thickness over the full film area has been determined by energy-dispersive Xray spectrome...

  14. Orientation and thickness dependence of magnetization at the interfacesof highly spin-polarized manganite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chopdekar, Rajesh V.; Arenholz, Elke; Suzuki, Y.

    2008-08-18

    We have probed the nature of magnetism at the surface of (001), (110) and (111)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films. The spin polarization of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films is not intrinsically suppressed at all surfaces and interfaces but is highly sensitive to both the epitaxial strain state as well as the substrate orientation. Through the use of soft x-ray spectroscopy, the magnetic properties of (001), (110) and (111)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrTiO{sub 3} interfaces have been investigated and compared to bulk magnetometry and resistivity measurements. The magnetization of (110) and (111)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrTiO{sub 3} interfaces are more bulk-like as a function of thickness whereas the magnetization at the (001)-oriented La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrTiO{sub 3} interface is suppressed significantly below a layer thickness of 20 nm. Such findings are correlated with the biaxial strain state of the La{sub 0.7}Sr{sub 0.3}MnO{sub 3} films; for a given film thickness it is the tetragonal distortion of (001) La{sub 0.7}Sr{sub 0.3}MnO{sub 3} that severely impacts the magnetization, whereas the trigonal distortion for (111)-oriented films and monoclinic distortion for (110)-oriented films have less of an impact. These observations provide evidence that surface magnetization and thus spin polarization depends strongly on the crystal surface orientation as well as epitaxial strain.

  15. Evidence for improvement of critical current by Ag in YBaCuO-Ag thick films

    Science.gov (United States)

    Dwir, B.; Kellett, B.; Mieville, L.; Pavuna, D.

    1991-04-01

    The evidence is reported for enhancement of critical current density J(c) in YBa2Cu3O(7-delta) thick films with the addition of Ag, which is correlated with improvements in structural properties. An improvement of 50 percent in J(c) (up to about 500 A/sq cm at T = 4.2 K) was obtained in films made from YBCO + 60 wt pct Ag powder, fabricated by the spin-on technique on (100) SrTiO3, which is correlated with improvements in structure. The resulting films are 10 microns thick, uniform, partially textured, and show good adherence. The critical temperature Tc is improved by the addition of Ag, and a reduction in the density of microcracks and in the amount of secondary phases in the sintered films was observed. Normal-state resistivity is reduced by almost three orders of magnitude, making these films potentially useful for electronic applications in interconnects and novel hybrid circuits.

  16. Evidence for improvement of critical current by Ag in YBaCuO-Ag thick films

    Energy Technology Data Exchange (ETDEWEB)

    Dwir, B.; Kellett, B.; Mieville, L.; Pavuna, D. (Institute of Micro- and Opto-electronics, Department of Physics, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland (CH))

    1991-04-15

    The evidence is reported for enhancement of critical current density {ital J}{sub {ital c}} in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thick films with the addition of Ag, which is correlated with improvements in structural properties. An improvement of 50% in {ital J}{sub {ital c}} (up to {similar to}500 A/cm{sup 2} at {ital T}=4.2 K) was obtained in films made from YBCO+60wt % Ag powder, fabricated by the spin-on technique on (100) SrTiO{sub 3}, which is correlated with improvements in structure. The resulting films are 10 {mu}m thick, uniform, partially textured, and show good adherence. The critical temperature {ital T}{sub {ital c}} is improved by the addition of Ag, and a reduction in the density of microcracks and in the amount of secondary phases in the sintered films was observed. Normal-state resistivity is reduced by almost three orders of magnitude, making these films potentially useful for electronic applications in interconnects and novel hybrid circuits.

  17. Thickness, stability and contact angle of liquid films on and inside nanofibres, nanotubes and nanochannels.

    Science.gov (United States)

    Mattia, Davide; Starov, Victor; Semenov, Sergey

    2012-10-15

    While the stability of liquid films on substrates is a classical topic of colloidal science, the availability of nanostructured materials, such as nanotubes, nanofibres and nanochannels, has raised the question of how the stability of liquid films and their wetting behaviour is affected by nanoscale confinement. This paper will present the conditions for the stability of liquid films on and inside cylindrical solid substrates with nanometre scale characteristic dimensions. It is shown that the stability is determined by an effective disjoining/conjoining pressure isotherm which differs from the corresponding disjoining/conjoining pressure isotherm of flat liquid films on flat solid substrates. From the former, the equilibrium contact angles of drops on an outer or inner surface of a cylindrical capillary have been calculated as a function of surface curvature, showing that the expressions for equilibrium contact angles vary for different geometries, in view of the difference in thickness of the film of uniform thickness with which the bulk liquid (drops or menisci) is at equilibrium. These calculations have been extended to the case of glass nanocapillaries and carbon nanotubes, finding good agreement with experimental results in the literature.

  18. Thickness dependence of electrical properties of PZT films deposited on metal substrates by laser-assisted aerosol deposition.

    Science.gov (United States)

    Baba, S; Tsuda, H; Akedo, J

    2008-05-01

    Dependence of electrical properties-dielectric, ferroelectric, and piezoelectric properties-on film thickness was studied for lead-zirconate titanate (PZT) thick films directly deposited onto stainless-steel (SUS) substrates in actuator devices by using a carbon dioxide (CO(2) ), laser assisted aerosol deposition technique. Optical spectroscopic analysis data and laser irradiation experiments revealed that absorption at a given wavelength by the film increased with increasing film thickness. Dielectric constant epsilon, remanent polarization value P(r), and coercive field strength E(c) of PZT films directly deposited onto a SUS-based piezoelectric actuator substrate annealed by CO(2) laser irradiation at 850 degrees C improved with increasing film thickness, and for films thicker than 25 microm, epsilon 800, P(r) 40 microC/cm(2), and E(c) 45 kV/cm. In contrast, the displacement of the SUS-based actuator with the laser-annealed PZT thick film decreased with increasing film thickness.

  19. Impact of nitrogen doping on growth and hydrogen impurity incorporation of thick nanocrystalline diamond films

    Institute of Scientific and Technical Information of China (English)

    Gu Li-Ping; Tang Chun-Jiu; Jiang Xue-Fan; J.L.Pintob

    2011-01-01

    A much larger amount of bonded hydrogen was found in thick nanocrystalline diamond (NCD) films produced by only adding 0.24% N2 into 4% CH4/H2 plasma, as compared to the high quality transparent microcrystalline diamond (MCD) films, grown using the same growth parameters except for nitrogen. These experimental results clearly evidence that defect formation and impurity incorporation (for example, N and H) impeding diamond grain growth is the main formation mechanism of NCD upon nitrogen doping and strongly support the model proposed in the literature that nitrogen competes with CHX (x = 1,2,3) growth species for adsorption sites.

  20. Properties of MgB{sub 2} thick film on silicon carbide substrate

    Energy Technology Data Exchange (ETDEWEB)

    Li Fen; Guo Tao; Zhang Kaicheng; Chen Liping; Chen Chinping; Feng Qingrong [Department of Physics and State Key Laboratory for Artificial Structure and Mesoscopic Physics, Peking University, Beijing 100871(China)

    2006-10-15

    We have successfully synthesized MgB{sub 2} thick films on 4H-SiC substrate by hybrid physical-chemical deposition (HPCVD). The films have transition temperature T{sub c} above 40 K. X-ray diffraction (XRD) shows the c-axis oriented structure of MgB{sub 2}, with Mg and small MgO impurities. The critical current density J{sub c}, estimated using the measured magnetic hysteresis loop and the Bean model, is 6 MA cm{sup -2} in self-field at 10 K.

  1. Thickness dependence of critical current density in MgB{sub 2} films fabricated by ex situ annealing of CVD-grown B films in Mg vapor

    Energy Technology Data Exchange (ETDEWEB)

    Hanna, Mina; Salama, Kamel [Department of Mechanical Engineering and Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Wang, Shufang; Xi, X X [Department of Physics, Pennsylvania State University, University Park, PA 16801 (United States); Redwing, Joan M [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16801 (United States)], E-mail: ksalama@uh.edu

    2009-01-15

    A study was performed to examine the J{sub c} behavior as a function of thickness in MgB{sub 2} films fabricated by ex situ annealing at 840 deg. C of boron films, grown by chemical vapor deposition, in Mg vapor. The film thicknesses range between 300 nm and 10 {mu}m. The values of J{sub c} range from 1.2 x 10{sup 7} A cm{sup -2} for 300 nm to 1.9 x 10{sup 5} A cm{sup -2} for 10 {mu}m film thicknesses at 20 K and self-field. The study shows that the critical current density (J{sub c}) in MgB{sub 2} films decreases with increasing film thickness, similar to that observed in YBCO-coated conductors. Moreover, our study shows that critical current (I{sub c}) reaches its maximum value of 728 A cm{sup -1} width at {approx}1 {mu}m thick MgB{sub 2} films at 20 K and self-field, which is, interestingly, the same thickness of pulsed-laser-deposited YBCO-coated conductors at which I{sub c} reaches its maximum value. The high J{sub c} values carried by our films show that the ex situ fabrication method can produce high quality MgB{sub 2} films at low processing temperatures, which is promising for RF cavity applications and coated-conductor wires and tapes.

  2. Negative dependence of surface magnetocrystalline anisotropy energy on film thickness in Co33Fe67 alloy

    Science.gov (United States)

    Wang, De-Lai; Cui, Ming-Qi; Yang, Dong-Liang; Dong, Jun-Cai; Xu, Wei

    2016-10-01

    In this work, the magnetocrystalline anisotropy energy (MAE) on the surface of Fe33Co67 alloy film is extracted from x-ray magnetic linear dichroism (XMLD) experiments. The result indicates that the surface MAE value is negatively correlated with thickness. Through spectrum calculations and analysis, we find that besides the thickness effect, another principal possible cause may be the shape anisotropy resulting from the presence of interface roughness. These two factors lead to different electron structures on the fermi surface with different exchange fields, which produces different spin-orbit interaction anisotropies. Project supported by the National Natural Science Foundation of China (Grant Nos. 11075176 and 11375131).

  3. Localized superconductivity in the quantum-critical region of the disorder-driven superconductor-insulator transition in TiN thin films.

    Science.gov (United States)

    Baturina, T I; Mironov, A Yu; Vinokur, V M; Baklanov, M R; Strunk, C

    2007-12-21

    We investigate low-temperature transport properties of thin TiN superconducting films in the vicinity of the disorder-driven superconductor-insulator transition. In a zero magnetic field, we find an extremely sharp separation between superconducting and insulating phases, evidencing a direct superconductor-insulator transition without an intermediate metallic phase. At moderate temperatures, in the insulating films we reveal thermally activated conductivity with the magnetic field-dependent activation energy. At very low temperatures, we observe a zero-conductivity state, which is destroyed at some depinning threshold voltage V{T}. These findings indicate the formation of a distinct collective state of the localized Cooper pairs in the critical region at both sides of the transition.

  4. Superconductor terahertz metamaterial

    CERN Document Server

    Gu, Jianqiang; Tian, Zhen; Cao, Wei; Xing, Qirong; Han, Jiaguang; Zhang, Weili

    2010-01-01

    We characterize the behaviour of split ring resonators made up of high-transition temperature YBCO superconductor using terahertz time domain spectroscopy. The superconductor metamaterial shows sharp change in the transmission spectrum at the fundamental inductive-capacitive resonance and the dipole resonance as the temperature dips below the transition temperature. Our results reveal that the high performance of such a metamaterial is limited by material imperfections and defects such as cracks, voids and secondary phases which play dominant role in partially impeding the flow of current causing dissipation of energy and electrical resistance to appear in the superconductor film.

  5. Long thickness-extensional waves in thin film bulk acoustic wave filters affected by interdigital electrodes.

    Science.gov (United States)

    Liu, Jing; Du, Jianke; Wang, Ji; Yang, Jiashi

    2017-03-01

    We studied free vibrations of thin-film bulk acoustic wave filters with interdigital electrodes theoretically using the scalar differential equations by Tiersten and Stevens. The filters are made from AlN or ZnO films on Si substrates with ground and driving electrodes. They operate with thickness-extensional modes. The basic vibration characteristics including resonant frequencies and mode shapes were obtained. Their dependence on various geometric parameters was examined. It was found that for properly design filters there exist trapped modes whose vibrations are strong in regions with a driving electrode and decay away from the electrode edges. These trapped modes are essentially long plate thickness-extensional modes modulated by the electrode fingers. The number of trapped modes is sensitive to the geometric parameters.

  6. Ferroelectric domain inversion and its stability in lithium niobate thin film on insulator with different thicknesses

    Science.gov (United States)

    Shao, Guang-hao; Bai, Yu-hang; Cui, Guo-xin; Li, Chen; Qiu, Xiang-biao; Geng, De-qiang; Wu, Di; Lu, Yan-qing

    2016-07-01

    Ferroelectric domain inversion and its effect on the stability of lithium niobate thin films on insulator (LNOI) are experimentally characterized. Two sets of specimens with different thicknesses varying from submicron to microns are selected. For micron thick samples (˜28 μm), domain structures are achieved by pulsed electric field poling with electrodes patterned via photolithography. No domain structure deterioration has been observed for a month as inspected using polarizing optical microscopy and etching. As for submicron (540 nm) films, large-area domain inversion is realized by scanning a biased conductive tip in a piezoelectric force microscope. A graphic processing method is taken to evaluate the domain retention. A domain life time of 25.0 h is obtained and possible mechanisms are discussed. Our study gives a direct reference for domain structure-related applications of LNOI, including guiding wave nonlinear frequency conversion, nonlinear wavefront tailoring, electro-optic modulation, and piezoelectric devices.

  7. Overview of thick-film technology as applied to solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Firor, K.; Hogan, S.

    1980-01-01

    Thick-film technology was developed by the electronics industry as a means of fabricating components and miniature circuitry. Today, the solar cell industry is looking at screen printing as an alternate to more expensive, high-vacuum techniques in several of the production steps during the manufacture of silicon solar cells. Screen printing is already fairly well established as a means of providing electrical contact to a cell and for the formation of a back surface field. Now under investigation are the possibilities of non-noble metal contacts and protective and antireflective coatings applied to solar cells by the use of screen printing. Most exciting is the work being done in the non-silicon area on the fabrication of the active layers of a solar cell, using thick-film inks made up of II-VI semiconductors.

  8. Electrical Capacitance Tomography Measurement of Flow Patterns and Film Thickness in a Thermosyphon

    Institute of Scientific and Technical Information of China (English)

    Jingtao LI; Qi CHEN; Xiangyuan DONG; Shi LIU

    2005-01-01

    An experimental study was performed to evaluate the suitability of using an electrical capacitance tomography (ECT) system to visualize the flow patterns, and to measure the film thickness of the annular flow in a two-phase closed thermosyphon (TPCT). The performance of the ECT system was examined over a range of flow conditions.The experimental data were compared with the visual observations and existing correlations. Results indicated that the ECT system, with the linear back projection (LBP) algorithm, could be used to give an on-line qualitative image of the flow patterns. The Landweber iteration algorithm with optimal step length was implemented off-line to reconstruct high-resolution images. Then, the images were analyzed to obtain the film thickness of the annular flow. The experimental data compared well with the Nusselt's equation in low vapor velocity range, but showed an increasing deficiency with the increase of vapor velocity.

  9. Neutron methods for the direct determination of the magnetic induction in thick films

    Energy Technology Data Exchange (ETDEWEB)

    Kozhevnikov, S.V., E-mail: kozhevn@nf.jinr.ru [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Ott, F. [CEA, IRAMIS, Laboratoire Léon Brillouin, F-91191 Gif sur Yvette (France); CNRS, IRAMIS, Laboratoire Léon Brillouin, F-91191 Gif sur Yvette (France); Radu, F. [Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Strasse 15, D-12489 Berlin (Germany)

    2016-03-15

    We review different neutron methods which allow extracting directly the value of the magnetic induction in thick films: Larmor precession, Zeeman spatial beam-splitting and neutron spin resonance. Resulting parameters obtained by the neutron methods and standard magnetometry technique are presented and compared. The possibilities and specificities of the neutron methods are discussed. - Highlights: • We present neutron methods for investigations of the thick magnetic films. • It is the methods for the direct determination of the magnetic induction. • Magnetic induction in bulk, at single interface and in a single domain. • It is Larmor precession, Zeeman spatial beam-splitting and neutron spin resonance. • These methods are complementary to polarized neutron reflectometry.

  10. Bandgap energy tuning of electrochemically grown ZnO thin films by thickness and electrodeposition potential

    Energy Technology Data Exchange (ETDEWEB)

    Marotti, R.E.; Guerra, D.N.; Machado, G.; Dalchiele, E.A. [Instituto de Fisica, Facultad de Ingenieria, Universidad de la Republica, Julio Herrera y Reissig 565, C.C. 30, Montevideo 11000 (Uruguay); Bello, C. [Unidad Central de Instrumentacion Cientifica UCIC, Facultad de Ciencias, Universidad de la Republica, Igua 4225, C.C. 10773, Montevideo 11400 (Uruguay)

    2004-05-01

    ZnO thin films were electrochemically deposited onto opaque and transparent substrates (copper and ITO). The electrolyte consisted of a 0.1M Zn(NO{sub 3}){sub 2} solution with the initial pH adjusted to 6.0, different electrodeposition potentials from E=-700 to -1200mV (saturated calomel electrode, SCE). The resulting samples have the structural, chemical and morphological properties of hexagonal ZnO, with thickness varying from less than 1{mu}m to almost 30{mu}m. The bandgap energy varies inversely with film thickness, ranging from less than 3.1 to 3.4eV. The bandgap also depends on the electrodeposition potential. This result allows to adjust the desired absorption edge within a 30nm wide region in the UV.

  11. Evaluation of Cadmium-Free Thick Film Materials on Alumina Substrates

    Energy Technology Data Exchange (ETDEWEB)

    L. H. Perdieu

    2009-09-01

    A new cadmium-free material system was successfully evaluated for the fabrication of thick film hybrid microcircuits at Honeywell Federal Manufacturing & Technologies (FM&T). The characterization involved screen printing, drying and firing two groups of resistor networks which were made using the current material system and the cadmium-free material system. Electrical, environmental and adhesion tests were performed on both groups to determine the more suitable material system. Additionally, untrimmed test coupons were evaluated to further characterize the new materials. The cadmiumfree material system did as well or better than the current material system. Therefore, the new cadmium-free material system was approved for use on production thick film product.

  12. Thickness and stoichiometry dependence of the thermal conductivity of GeSbTe films

    Science.gov (United States)

    Reifenberg, John P.; Panzer, Matthew A.; Kim, SangBum; Gibby, Aaron M.; Zhang, Yuan; Wong, Simon; Wong, H.-S. Philip; Pop, Eric; Goodson, Kenneth E.

    2007-09-01

    Thermal conduction in GeSbTe films strongly influences the writing energy and time for phase change memory (PCM) technology. This study measures the thermal conductivity of Ge2Sb2Te5 between 25 and 340°C for layers with thicknesses near 60, 120, and 350nm. A strong thickness dependence of the thermal conductivity is attributed to a combination of thermal boundary resistance (TBR) and microstructural imperfections. Stoichiometric variations significantly alter the phase transition temperatures but do not strongly impact the thermal conductivity at a given temperature. This work makes progress on extracting the TBR for Ge2Sb2Te5 films, which is a critical unknown parameter for PCM simulations.

  13. DESIGN OF FILM THICKNESS INSTRUMENT FOR FIBRE POLYMER COMPOSITES TRIBOLOGICAL EXPERIMENTS

    Directory of Open Access Journals (Sweden)

    B. F. YOUSIF

    2014-04-01

    Full Text Available New technique to measure film thickness in tribological experiments is presented in the current study. The technique is based on strain gauges circuit fixed on a lever of the block on ring (BOR machine. Conversion of strain gauge readings was made to determine the film thickness values. For testing purposes, experiments were conducted using the new machine to investigate the wear performance of glass/polyester composites. The tests were performed against aluminium counterface at different applied loads (0.5 N to 3 N for 10 minutes sliding time under wet contact conditions. From the results, the new technique highly assisted to analysis the tribological results. The SEM showed different damage features.

  14. DETERMINATION OF LIQUID FILM THICKNESS FOLLOWING DRAINING OF CONTACTORS, VESSELS, AND PIPES IN THE MCU PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M; Fernando Fondeur, F; Samuel Fink, S

    2006-06-06

    The Department of Energy (DOE) identified the caustic side solvent extraction (CSSX) process as the preferred technology to remove cesium from radioactive waste solutions at the Savannah River Site (SRS). As a result, Washington Savannah River Company (WSRC) began designing and building a Modular CSSX Unit (MCU) in the SRS tank farm to process liquid waste for an interim period until the Salt Waste Processing Facility (SWPF) begins operations. Both the solvent and the strip effluent streams could contain high concentrations of cesium which must be removed from the contactors, process tanks, and piping prior to performing contactor maintenance. When these vessels are drained, thin films or drops will remain on the equipment walls. Following draining, the vessels will be flushed with water and drained to remove the flush water. The draining reduces the cesium concentration in the vessels by reducing the volume of cesium-containing material. The flushing, and subsequent draining, reduces the cesium in the vessels by diluting the cesium that remains in the film or drops on the vessel walls. MCU personnel requested that Savannah River National Laboratory (SRNL) researchers conduct a literature search to identify models to calculate the thickness of the liquid films remaining in the contactors, process tanks, and piping following draining of salt solution, solvent, and strip solution. The conclusions from this work are: (1) The predicted film thickness of the strip effluent is 0.010 mm on vertical walls, 0.57 mm on horizontal walls and 0.081 mm in horizontal pipes. (2) The predicted film thickness of the salt solution is 0.015 mm on vertical walls, 0.74 mm on horizontal walls, and 0.106 mm in horizontal pipes. (3) The predicted film thickness of the solvent is 0.022 mm on vertical walls, 0.91 mm on horizontal walls, and 0.13 mm in horizontal pipes. (4) The calculated film volume following draining is: (a) Salt solution receipt tank--1.6 gallons; (b) Salt solution feed

  15. Thickness dependence of piezoelectric properties of BiFeO3 films fabricated using rf magnetron sputtering system

    Science.gov (United States)

    Aramaki, Masaaki; Kariya, Kento; Yoshimura, Takeshi; Murakami, Shuichi; Fujimura, Norifumi

    2016-10-01

    The piezoelectric property of BiFeO3 films prepared on a (100) LaNiO3/Si(100) substrate using an rf magnetron sputtering system was investigated for their applications in MEMS vibration energy harvesters. The X-ray diffraction profiles indicate that (100)-oriented BiFeO3 films with thicknesses from 450 to 1750 nm were obtained at a deposition temperature of 510 °C. All the films showed well-defined ferroelectric hysteresis loops at room temperature. The thickness dependence of crystallinity and electrical properties indicated that the films have a bottom layer with a high defect density. The e 31,f piezoelectric coefficient and electromechanical coupling factor (k\\text{31,f}2) increase with increasing film thickness and reach -3.2 C/m2 and 3.3%, respectively, at a thickness of 1750 nm, which is considered to be caused by the decrease in defect density.

  16. Effect of preheating on the film thickness of contemporary composite restorative materials

    OpenAIRE

    Dimitrios Dionysopoulos; Kosmas Tolidis; Paris Gerasimou; Eugenia Koliniotou-Koumpia

    2014-01-01

    Background/purpose: Recently, the placement of composite materials at an elevated temperature has been proposed in order to increase their flow for better adaptation in cavity walls. The aim of this in vitro study was to evaluate the effect of preheating on the film thickness of a variety of commercially available conventional composites and to compare them with those obtained from a variety of flowable composites at room temperature. Materials and methods: The composites were three nanohy...

  17. Investigation of Polymer Thick-film Piezoresistors for Medical Wrist Rehabilitation and Artificial Knee Load Sensors

    OpenAIRE

    2014-01-01

    Readily-available and low-cost commercial polymer-based composite materials, such as standard epoxy-fibreglass printed circuit board (PCB) substrates and resin-carbon thick-film piezoresistors, were evaluated as a solution for medical force sensors, such as a wrist rehabilitation device and an implantable wireless artificial knee force sensor. We show that such materials have high sensitivity, and sufficient short-term stability – provided careful mechanical design and materials selection are...

  18. CO Responses of Sensors Based on Cerium Oxide Thick Films Prepared from Clustered Spherical Nanoparticles

    OpenAIRE

    Woosuck Shin; Takafumi Akamatsu; Toshio Itoh; Ichiro Matsubara; Noriya Izu

    2013-01-01

    Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nano...

  19. Thick-Film Carbon Dioxide Sensor via Anodic Adsorbate Stripping Technique and Its Structural Dependence

    OpenAIRE

    Chung-Chiun Liu; Shih-Han Wang; Kanokorn Photinon

    2009-01-01

    A three-electrode based CO2 sensor was fabricated using thick-film technology. The performance of this sensor was further enhanced by incorporating platinum nanoparticles onto the working electrode surface. An eight-fold increase in the signal output was obtained from the electrode with the platinum nanoparticles. The sensing output was linearly related to the CO2 presented. Stability measurements demonstrated that the decline of the active surface area and the sensitivity of the sensor were ...

  20. Colloidal processing of PMN-PT thick films for piezoelectric sensor applications

    Science.gov (United States)

    Luo, Hongyu

    65%Pb(Mg1/3Nb2/3)O3-35%PbTiO3 (65PMN-35PT, or PMN-PT) is a highly piezoelectric ceramic with superior piezoelectric coefficients over the more popular Pb(Zr0.5Ti0.5)O 3 (PZT). Because of its complex chemistry and high volatility of lead above 1000°C, the perovskite phase of PMN-PT is hard to process and has prevented PMN-PT from various piezoelectric applications, especially in the new area of piezoelectric micro-electro-mechanical systems (PMEMS) involving thick or thin piezoelectric films. In this thesis, a novel precursor suspension method is introduced that substantially lowers the sintering temperature of PMN-PT to 850°C from a PMN precursor powder made by coating Mg(OH) 2 on Nb2O5 particles. The precursor suspension method entails suspending PMN powders in PT precursor and uses the reaction sintering capability of PMN with nano-sized PT in the temperature range of 800°C˜1000°C. Moreover, free-standing PMN-PT thick films were obtained by tape casting the PMN-PT powder. This new geometry of PMN-PT shows giant electric-field enhanced piezoelectric responses comparable with those of single crystals. As an example of application, the PMN-PT thick film is bonded to a thinner layer of copper by electroplating and made into piezoelectric cantilever sensors. In conclusion, the colloidal suspension processing method produces free-standing PMN-PT thick films with ultrahigh piezoelectric properties.

  1. Electrical properties of thick film capacitors based on barium titanate glass formulations

    Energy Technology Data Exchange (ETDEWEB)

    Leppaevuori, S.; Uusimaeki, A.; Hannula, T.

    1981-12-18

    We carried out an investigation of the effects of the glass content of the dielectric layer of thick film capacitors with a barium titanate glass formulation on the capacitance density, loss factor and breakdown voltage of the capacitors. These effects were studied by varying the firing temperature and glass content of the dielectric paste and by using different types of electrode paste. The characteristics of a test capacitor were also measured.

  2. Characterization of Thick and Thin Film SiCN for Pressure Sensing at High Temperatures

    Directory of Open Access Journals (Sweden)

    Rama B. Bhat

    2010-02-01

    Full Text Available Pressure measurement in high temperature environments is important in many applications to provide valuable information for performance studies. Information on pressure patterns is highly desirable for improving performance, condition monitoring and accurate prediction of the remaining life of systems that operate in extremely high temperature environments, such as gas turbine engines. A number of technologies have been recently investigated, however these technologies target specific applications and they are limited by the maximum operating temperature. Thick and thin films of SiCN can withstand high temperatures. SiCN is a polymer-derived ceramic with liquid phase polymer as its starting material. This provides the advantage that it can be molded to any shape. CERASET™ also yields itself for photolithography, with the addition of photo initiator 2, 2-Dimethoxy-2-phenyl-acetophenone (DMPA, thereby enabling photolithographical patterning of the pre-ceramic polymer using UV lithography. SiCN fabrication includes thermosetting, crosslinking and pyrolysis. The technology is still under investigation for stability and improved performance. This work presents the preparation of SiCN films to be used as the body of a sensor for pressure measurements in high temperature environments. The sensor employs the phenomenon of drag effect. The pressure sensor consists of a slender sensitive element and a thick blocking element. The dimensions and thickness of the films depend on the intended application of the sensors. Fabrication methods of SiCN ceramics both as thin (about 40–60 µm and thick (about 2–3 mm films for high temperature applications are discussed. In addition, the influence of thermosetting and annealing processes on mechanical properties is investigated.

  3. Characterization of Thick and Thin Film SiCN for Pressure Sensing at High Temperatures

    Science.gov (United States)

    Leo, Alfin; Andronenko, Sergey; Stiharu, Ion; Bhat, Rama B.

    2010-01-01

    Pressure measurement in high temperature environments is important in many applications to provide valuable information for performance studies. Information on pressure patterns is highly desirable for improving performance, condition monitoring and accurate prediction of the remaining life of systems that operate in extremely high temperature environments, such as gas turbine engines. A number of technologies have been recently investigated, however these technologies target specific applications and they are limited by the maximum operating temperature. Thick and thin films of SiCN can withstand high temperatures. SiCN is a polymer-derived ceramic with liquid phase polymer as its starting material. This provides the advantage that it can be molded to any shape. CERASET™ also yields itself for photolithography, with the addition of photo initiator 2, 2-Dimethoxy-2-phenyl-acetophenone (DMPA), thereby enabling photolithographical patterning of the pre-ceramic polymer using UV lithography. SiCN fabrication includes thermosetting, crosslinking and pyrolysis. The technology is still under investigation for stability and improved performance. This work presents the preparation of SiCN films to be used as the body of a sensor for pressure measurements in high temperature environments. The sensor employs the phenomenon of drag effect. The pressure sensor consists of a slender sensitive element and a thick blocking element. The dimensions and thickness of the films depend on the intended application of the sensors. Fabrication methods of SiCN ceramics both as thin (about 40–60 μm) and thick (about 2–3 mm) films for high temperature applications are discussed. In addition, the influence of thermosetting and annealing processes on mechanical properties is investigated. PMID:22205871

  4. Influence of thickness on physical properties of vacuum evaporated polycrystalline CdTe thin films for solar cell applications

    Science.gov (United States)

    Chander, Subhash; Dhaka, M. S.

    2016-02-01

    This paper presents the influence of thickness on physical properties of polycrystalline CdTe thin films. The thin films of thickness 450 nm, 650 nm and 850 nm were deposited employing thermal vacuum evaporation technique on glass and indium tin oxide (ITO) coated glass substrates. The physical properties of these as-grown thin films were investigated employing the X-ray diffraction (XRD), source meter, UV-Vis spectrophotometer, scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). The structural analysis reveals that the films have zinc-blende cubic structure and polycrystalline in nature with preferred orientation (111). The structural parameters like lattice constant, interplanar spacing, grain size, strain, dislocation density and number of crystallites per unit area are calculated. The average grain size and optical band gap are found in the range 15.16-21.22 nm and 1.44-1.63 eV respectively and observed to decrease with thickness. The current-voltage characteristics show that the electrical conductivity is observed to decrease with thickness. The surface morphology shows that films are free from crystal defects like pin holes and voids as well as homogeneous and uniform. The EDS patterns show the presence of cadmium and tellurium elements in the as grown films. The experimental results reveal that the film thickness plays significant role on the physical properties of as-grown CdTe thin films and higher thickness may be used as absorber layer to solar cells applications.

  5. Study of micron-thick MgB{sub 2} films on niobium substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang Chenggang; Yao Dan; Li Fen; Zhang Kaicheng; Feng Qingrong; Gan Zizhao [School of Physics and State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Peking University, Beijing 100871 (China)

    2007-03-15

    1 {mu}m thick polycrystalline MgB{sub 2} films have been grown on commercial niobium sheets using the hybrid physical-chemical vapour deposition technique (HPCVD). Their zero-resistance transition temperature T{sub c}{sup 0} ranges from 38 to 39 K and the transition temperature width {delta}T{sub c} is about 0.1-0.2 K. The films are composed of regular plate-shaped MgB{sub 2} crystallites and have lattice constants about the bulk values. Some diffusion regions were observed at the interface between the film and the substrate by a line scanning spectra of energy-dispersive x-ray spectroscopy (EDX) on the cross section, which might enhance the adhesion of the coated layer to the substrate. The critical current densities, J{sub c}, of these films, calculated by the Bean model, are greater than 5 x 10{sup 6} A cm{sup -2} at 10 K in zero field. Although tiny cracks in the film were created by bending the sample on a curved surface with a radius of 1.4 mm, however, T{sub c}{sup 0} of the bent film was not affected and remained about 39 K, which indicates that the sample has a certain ductibility.

  6. Thickness dependence of microstructure in LaCaMnO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gross, G.M.; Razavi, F.S.; Praus, R.B.; Habermeier, H.-U. E-mail: huh@servix.mpi-stuttgart.mpg.de

    2000-03-01

    Introducing biaxial strain in doped lanthanum manganite thin films is an excellent tool to modify the electrical and transport properties systematically by controlled changes of the microstructure on an atomic scale. We deposited La{sub 2/3}Ca{sub 1/3}MnO{sub 3} thin films onto SrTiO{sub 3} single-crystal substrates under reproducible conditions in an optimized pulsed laser deposition process. A thickness range of 40 to 500 nm was chosen for the manganite layers to investigate the variation of the average lattice parameters with thickness using X-ray diffraction. We re-investigated the samples after annealing to determine the structural aspects of the relaxation behavior of the layers. A second set of samples was prepared with an analogous in situ annealing process. AFM was applied to examine the morphology and grain size of the layers. Due to a thermally induced strain relaxation process the thicker films show a gradual approach of the out-of-plane lattice constant to the bulk ceramic value. Further relaxation could be achieved with an annealing at 900 deg. C for 1 h. Lattice parameter changes with varying thickness and annealing processes are correlated with transport and magnetic properties.

  7. Analysis of flow development in centrifugal atomization: Part I. Film thickness of a fully spreading melt

    Science.gov (United States)

    Zhao, Y. Y.

    2004-09-01

    Centrifugal atomization of metal melts is a cost-effective process for powder production and spray deposition. The properties of the as-produced powder and deposit are determined primarily by the characteristics of the atomized droplets, which in turn are largely dependent on the flow development of the melt on the atomizer. This paper develops a model for analysing the flow development of a fully spreading melt on and off the atomizing cup. The model can be used to calculate the velocity and film thickness of the melt as a function of melt volume flow rate, cup rotation speed, cup radius and cup slope angle, as well as to predict the trajectory of the spray off the cup. The model implies that the disintegration of a fully spreading melt takes place in the region just off the cup edge and the film thickness at the cup edge is a critical factor determining the sizes of the resultant droplets. The film thickness at the cup edge is shown to decrease with decreasing volume flow rate, with increasing cup rotation speed, with increasing cup radius and with decreasing cup slope angle.

  8. Ultrathin magnesia films as support for molecules and metal clusters: Tuning reactivity by thickness and composition

    Energy Technology Data Exchange (ETDEWEB)

    Vaida, Mihai E.; Bernhardt, Thorsten M. [Institute of Surface Chemistry and Catalysis, University of Ulm (Germany); Barth, Clemens [CINAM-CNRS, Marseille (France); Esch, Friedrich; Heiz, Ueli [Department of Chemistry, Technical University of Munich, Garching (Germany); Landman, Uzi [School of Physics, Georgia Institute of Technology, Atlanta, Georgia (United States)

    2010-05-15

    Ultrathin metal oxide films have attracted considerable interest in recent years as versatile substrate for the design of nanocatalytic model systems. In particular, it has been proposed theoretically and confirmed experimentally that the electronic structure of adsorbates can be influenced by the layer thickness and the stoichiometry, i.e., the type and number of defects, of the oxide film. This has important consequences on the chemical reactivity of the oxide surface itself and of oxide supported metal clusters. It also opens new possibilities to influence and to control chemical reactions occurring at the surface of these systems. The present feature focuses on very recent experiments that illustrate the effects of a proper adjustment of layer thickness and composition of ultrathin MgO(100) films on chemical transformations. On the magnesia surface itself, the photodissociation dynamics of methyl iodide molecules is investigated via femtosecond-laser pump-probe mass spectrometry. Furthermore, the catalytic oxidation of carbon monoxide at mass-selected Au{sub 20} clusters deposited on magnesia is explored through temperature programmed reaction measurements. In the latter case, detailed first principles calculations are able to correlate the experimentally observed reactivity with structural dimensionality changes that are induced by the changing thickness and composition of the magnesia support. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. Electrochemical Properties of RuO2 Electrodes as a Function of Thin Film Thickness

    Science.gov (United States)

    Li, Xiang; Xiong, Jian; Luo, Yuan; Luo, Yongmei

    2017-09-01

    A thin film RuO2 electrode was prepared by spin coating thermal decomposition methods. Precursor containing RuCl3·nH2O and isopropyl alcohol was coated on tantalum substrate and annealed at 250-260°C for 3 h to form a thin film RuO2 electrode of about 2.5 μm, 5.6 μm, 11.4 μm, and 14.5 μm in thickness. X-ray diffraction revealed that peak intensities of those electrodes were similar and close to each other. Scanning electron microscopy showed that thin film of 5.6 μm in thickness was dense and free of cracks. Electrochemical performances of electrodes were examined by cyclic voltammetry, galvanostatic charge/discharge as well as equivalent series resistance. The highest specific capacitance value of 725 F g-1 was registered for the electrode of 5.6 μm in thickness with good constant current charge/discharge and equivalent series resistance of 0.36 Ω as well as cyclic stability.

  10. A reliable control system for measurement on film thickness in copper chemical mechanical planarization system.

    Science.gov (United States)

    Li, Hongkai; Qu, Zilian; Zhao, Qian; Tian, Fangxin; Zhao, Dewen; Meng, Yonggang; Lu, Xinchun

    2013-12-01

    In recent years, a variety of film thickness measurement techniques for copper chemical mechanical planarization (CMP) are subsequently proposed. In this paper, the eddy-current technique is used. In the control system of the CMP tool developed in the State Key Laboratory of Tribology, there are in situ module and off-line module for measurement subsystem. The in situ module can get the thickness of copper film on wafer surface in real time, and accurately judge when the CMP process should stop. This is called end-point detection. The off-line module is used for multi-points measurement after CMP process, in order to know the thickness of remained copper film. The whole control system is structured with two levels, and the physical connection between the upper and the lower is achieved by the industrial Ethernet. The process flow includes calibration and measurement, and there are different algorithms for two modules. In the process of software development, C++ is chosen as the programming language, in combination with Qt OpenSource to design two modules' GUI and OPC technology to implement the communication between the two levels. In addition, the drawing function is developed relying on Matlab, enriching the software functions of the off-line module. The result shows that the control system is running stably after repeated tests and practical operations for a long time.

  11. A reliable control system for measurement on film thickness in copper chemical mechanical planarization system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongkai; Qu, Zilian; Zhao, Qian; Tian, Fangxin; Zhao, Dewen; Meng, Yonggang; Lu, Xinchun [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2013-12-15

    In recent years, a variety of film thickness measurement techniques for copper chemical mechanical planarization (CMP) are subsequently proposed. In this paper, the eddy-current technique is used. In the control system of the CMP tool developed in the State Key Laboratory of Tribology, there are in situ module and off-line module for measurement subsystem. The in situ module can get the thickness of copper film on wafer surface in real time, and accurately judge when the CMP process should stop. This is called end-point detection. The off-line module is used for multi-points measurement after CMP process, in order to know the thickness of remained copper film. The whole control system is structured with two levels, and the physical connection between the upper and the lower is achieved by the industrial Ethernet. The process flow includes calibration and measurement, and there are different algorithms for two modules. In the process of software development, C++ is chosen as the programming language, in combination with Qt OpenSource to design two modules’ GUI and OPC technology to implement the communication between the two levels. In addition, the drawing function is developed relying on Matlab, enriching the software functions of the off-line module. The result shows that the control system is running stably after repeated tests and practical operations for a long time.

  12. Response of Ag Thick Film Microstripline due to Superstrate Strontium Substituted Bismuth Manganites

    Directory of Open Access Journals (Sweden)

    S.N. Mathad

    2014-06-01

    Full Text Available The purpose of this paper is to describe the use of strontium-substituted bismuth manganites bulk ceramic superstrate on Ag thick film microstripline, to modify its response and measure complex permittivity as a function of strontium. Bismuth strontium manganites (Bi1 − xSrxMnO3 have been synthesized by solid state sintering technique. The perturbation obtained in the transmittance and reflectance of thick film microstripline due to the Bi1 − xSrxMnO3 (0.20  x  0.50 overlay has been used to obtain the permittivity at microwave frequencies in X and Ku band range. Due to the overlay of Bismuth strontium manganites (BSM pellets a substantial increase in the effective dielectric constant was observed in X band more compared to Ku band. The in-touch overlay method provides ease loading and unloading. The perturbation obtained in the transmittance and reflectance of thick film microstripline due to the bismuth strontium manganites overlay has been used to obtain the permittivity.

  13. Ethanol gas sensing properties of Al2O3-doped ZnO thick film resistors

    Indian Academy of Sciences (India)

    D R Patil; L A Patil; D P Amalnerkar

    2007-12-01

    The characterization and ethanol gas sensing properties of pure and doped ZnO thick films were investigated. Thick films of pure zinc oxide were prepared by the screen printing technique. Pure zinc oxide was almost insensitive to ethanol. Thick films of Al2O3 (1 wt%) doped ZnO were observed to be highly sensitive to ethanol vapours at 300°C. Aluminium oxide grains dispersed around ZnO grains would result into the barrier height among the grains. Upon exposure of ethanol vapours, the barrier height would decrease greatly leading to drastic increase in conductance. It is reported that the surface misfits, calcination temperature and operating temperature can affect the microstructure and gas sensing performance of the sensor. The efforts are, therefore, made to create surface misfits by doping Al2O3 into zinc oxide and to study the sensing performance. The quick response and fast recovery are the main features of this sensor. The effects of microstructure and additive concentration on the gas response, selectivity, response time and recovery time of the sensor in the presence of ethanol vapours were studied and discussed.

  14. Thickness control in electrophoretic deposition of WO{sub 3} nanofiber thin films for solar water splitting

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yuanxing; Lee, Wei Cheat; Canciani, Giacomo E.; Draper, Thomas C.; Al-Bawi, Zainab F. [Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ (United Kingdom); Bedi, Jasbir S. [School of Public Health & Zoonoses, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana 141004 Punjab (India); Perry, Christopher C. [Division of Biochemistry, School of Medicine, Loma Linda University, Loma Linda, CA 92350 (United States); Chen, Qiao, E-mail: qiao.chen@sussex.ac.uk [Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ (United Kingdom)

    2015-12-15

    Graphical abstract: - Highlights: • A novel method combining electrospinning and electrophoretic deposition was established for the creation of nanostructured semiconductor thin films. • The created thin films displayed a high chemical stability with a controllable thickness. • The PEC water splitting performance of the thin films was optimized by fine-tuning the thickness of the films. • A maximum photoconversion efficiency was achieved by 18 μm nanofibrous thin films. - Abstract: Electrophoretic deposition (EPD) of ground electrospun WO{sub 3} nanofibers was applied to create photoanodes with controlled morphology for the application of photoelectrochemical (PEC) water splitting. The correlations between deposition parameters and film thicknesses were investigated with theoretical models to precisely control the morphology of the nanostructured porous thin film. The photoconversion efficiency was further optimized as a function of film thickness. A maximum photoconversion efficiency of 0.924% from electrospun WO{sub 3} nanofibers that EPD deposited on a substrate was achieved at a film thickness of 18 μm.

  15. Evaluation of feasibility of measuring EHD film thickness associated with cryogenic fluids. [for space shuttle main engine bearings

    Science.gov (United States)

    Kannel, J. W.; Merriman, T. L.; Stockwell, R. D.; Dufrane, K. F.

    1983-01-01

    The feasibility of measuring elastohydrodynamic (EHD) films as formed with a cryogenic (LN2) fluid is evaluated. Modifications were made to an existing twin disk EHD apparatus to allow for disk lubrication with liquid nitrogen. This disk apparatus is equipped with an X-ray system for measuring the thickness of any lubricant film that is formed between the disks. Several film thickness experiments were conducted with the apparatus which indicate that good lubrication films are filmed with LN2. In addition to the film thickness studies, failure analyses of three bearings were conducted. The HPOTP turbine end bearings had experienced axial loads of 36,000 to 44,000 N (8,000 to 10,000 lb). High continuous radial loads were also experienced, which were most likely caused by thermal growth of the inner race. The resulting high internal loads caused race spalling and ball wear to occur.

  16. Thickness effect on the structure, grain size, and local piezoresponse of self-polarized lead lanthanum zirconate titanate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Melo, M.; Araújo, E. B., E-mail: eudes@dfq.feis.unesp.br [Departamento de Física e Química, Faculdade de Engenharia de Ilha Solteira, UNESP—Univ. Estadual Paulista, 15385-000 Ilha Solteira, SP (Brazil); Shvartsman, V. V. [Institute for Materials Science, University Duisburg-Essen, 45141 Essen (Germany); Shur, V. Ya. [Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation); Kholkin, A. L. [Institute of Natural Sciences, Ural Federal University, 620000 Ekaterinburg (Russian Federation); Department of Physics and CICECO—Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro (Portugal)

    2016-08-07

    Polycrystalline lanthanum lead zirconate titanate (PLZT) thin films were deposited on Pt/TiO{sub 2}/SiO{sub 2}/Si substrates to study the effects of the thickness and grain size on their structural and piezoresponse properties at nanoscale. Thinner PLZT films show a slight (100)-orientation tendency that tends to random orientation for the thicker film, while microstrain and crystallite size increases almost linearly with increasing thickness. Piezoresponse force microscopy and autocorrelation function technique were used to demonstrate the existence of local self-polarization effect and to study the thickness dependence of correlation length. The obtained results ruled out the bulk mechanisms and suggest that Schottky barriers near the film-substrate are likely responsible for a build-in electric field in the films. Larger correlation length evidence that this build-in field increases the number of coexisting polarization directions in larger grains leading to an alignment of macrodomains in thinner films.

  17. Thickness-dependent cooperative aging in polycrystalline films of antiferromagnet CoO

    Science.gov (United States)

    Ma, Tianyu; Cheng, Xiang; Boettcher, Stefan; Urazhdin, Sergei; Novozhilova, Lydia

    2016-07-01

    We demonstrate that thin polycrystalline films of antiferromagnet CoO, in bilayers with ferromagnetic Permalloy, exhibit slow power-law aging of their magnetization state. The aging characteristics are remarkably similar to those previously observed in thin epitaxial Fe50Mn50 films, indicating that these behaviors are likely generic to ferromagnet/antiferromagnet bilayers. In very thin films, aging is observed over a wide temperature range. In thicker CoO, aging effects become reduced at low temperatures. Aging entirely disappears for large CoO thicknesses. We also investigate the dependence of aging characteristics on temperature and magnetic history. Analysis shows that the observed behaviors are inconsistent with the Neel-Arrhenius model of thermal activation, and are instead indicative of cooperative aging of the antiferromagnet. Our results provide new insights into the mechanisms controlling the stationary states and dynamics of ferromagnet/antiferromagnet bilayers, and potentially other frustrated magnetic systems.

  18. Study of Microstructural Parameters of Screen Printed In2O3 Thick Film Sensors

    Directory of Open Access Journals (Sweden)

    Sushma KULKARNI

    2011-08-01

    Full Text Available Indium Oxide (In2O3 thick films were prepared on alumina substrate by using standard screen printing technique. These films were dried and fired at temperatures between 650 0C to 950 0C for two hours in air atmosphere. The material characterization was done using X-ray energy dispersive analysis (EDAX, X-ray diffraction (XRD and a scanning electron microscope (SEM. The deposited films were polycrystalline in nature with a preferred orientation along the (222 plane. Structural parameters such as the crystallite size, texture coefficient, RMS microstrain, dislocation density and stacking fault probability have been studied. The results indicate that reported parameters changes with firing temperature. The crystallite size changes from 26.8 nm to 31 nm with respect to the firing temperature.

  19. Narrow thermal hysteresis of NiTi shape memory alloy thin films with submicrometer thickness

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Huilong; Hamilton, Reginald F., E-mail: rfhamilton@psu.edu; Horn, Mark W. [Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2016-09-15

    NiTi shape memory alloy (SMA) thin films were fabricated using biased target ion beam deposition (BTIBD), which is a new technique for fabricating submicrometer-thick SMA thin films, and the capacity to exhibit shape memory behavior was investigated. The thermally induced shape memory effect (SME) was studied using the wafer curvature method to report the stress-temperature response. The films exhibited the SME in a temperature range above room temperature and a narrow thermal hysteresis with respect to previous reports. To confirm the underlying phase transformation, in situ x-ray diffraction was carried out in the corresponding phase transformation temperature range. The B2 to R-phase martensitic transformation occurs, and the R-phase transformation is stable with respect to the expected conversion to the B19′ martensite phase. The narrow hysteresis and stable R-phase are rationalized in terms of the unique properties of the BTIBD technique.

  20. Thickness Dependency of Thin Film Samaria Doped Ceria for Oxygen Sensing

    Energy Technology Data Exchange (ETDEWEB)

    Sanghavi, Rahul P.; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Jiang, Weilin; Varga, Tamas; Nachimuthu, Ponnusamy; Engelhard, Mark H.; Shutthanandan, V.; Thevuthasan, Suntharampillai; Kayani, Asghar N.; Prasad, Shalini

    2011-01-01

    High temperature oxygen sensors are widely used for exhaust gas monitoring in automobiles. This particular study explores the use of thin film single crystalline samaria doped ceria as the oxygen sensing material. Desired signal to noise ratio can be achieved in a material system with high conductivity. From previous studies it is established that 6 atomic percent samarium doping is the optimum concentration for thin film samaria doped ceria to achieve high ionic conductivity. In this study, the conductivity of the 6 atomic percent samaria doped ceria thin film is measured as a function of the sensing film thickness. Hysteresis and dynamic response of this sensing platform is tested for a range of oxygen pressures from 0.001 Torr to 100 Torr for temperatures above 673 K. An attempt has been made to understand the physics behind the thickness dependent conductivity behavior of this sensing platform by developing a hypothetical operating model and through COMSOL simulations. This study can be used to identify the parameters required to construct a fast, reliable and compact high temperature oxygen sensor.

  1. Performance Evaluation of an Oxygen Sensor as a Function of the Samaria Doped Ceria Film Thickness

    Energy Technology Data Exchange (ETDEWEB)

    Sanghavi, Rahul P.; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Nachimuthu, Ponnusamy; Engelhard, Mark H.; Shutthanandan, V.; Jiang, Weilin; Thevuthasan, Suntharampillai; Kayani, Asghar N.; Prasad, Shalini

    2010-12-01

    The current demand in the automobile industry is in the control of air-fuel mixture in the combustion engine of automobiles. Oxygen partial pressure can be used as an input parameter for regulating or controlling systems in order to optimize the combustion process. Our goal is to identify and optimize the material system that would potentially function as the active sensing material for such a device that monitors oxygen partial pressure in these systems. We have used thin film samaria doped ceria (SDC) as the sensing material for the sensor operation, exploiting the fact that at high temperatures, oxygen vacancies generated due to samarium doping act as conducting medium for oxygen ions which hop through the vacancies from one side to the other contributing to an electrical signal. We have recently established that 6 atom % Sm doping in ceria films has optimum conductivity. Based on this observation, we have studied the variation in the overall conductivity of 6 atom % samaria doped ceria thin films as a function of thickness in the range of 50 nm to 300 nm at a fixed bias voltage of 2 volts. A direct proportionality in the increase in the overall conductivity is observed with the increase in sensing film thickness. For a range of oxygen pressure values from 1 mTorr to 100 Torr, a tolerable hysteresis error, good dynamic response and a response time of less than 10 seconds was observed

  2. Thickness dependent electronic structure and morphology of rubrene thin films on metal, semiconductor, and dielectric substrates

    Science.gov (United States)

    Sinha, Sumona; Mukherjee, M.

    2013-08-01

    The evolution of the electronic structure and morphology of rubrene thin films on noble-metal, semiconductor and dielectric substrates have been investigated as a function of thickness of deposited films by using photoelectron spectroscopy and atomic force microscopy. The clean polycrystalline Au and Ag were used as noble-metals, whereas, H passivated and SiO2 coated Si (100) were used as semiconductors and dielectric substrates. Discussion and comparison on interface dipole, energy level alignment, and surface morphology for the four cases are presented. The formation of dipole at metallic interfaces is found to occur due to push back effect. S parameter obtained from the variation of barrier height with the change of work function of the contacting metal indicates moderately weak interaction between rubrene and the metal substrates. The thickness dependent energy level alignment of the physisorbed rubrene films on different substrates is explained by a dielectric model in terms of electrostatic screening of photo-holes or photoemission final state relaxation energy. Films on all the substrates are found to grow following Stranski-Krastnov type growth mode and are more ordered at higher coverage.

  3. Space Charge Distribution Measurement in Insulation Film with Thickness of Several Tens μm

    Science.gov (United States)

    Hamano, Akihiro; Tanaka, Yasuhiro; Maeno, Takashi

    Since electronic equipment is required to be smaller and lighter, an insulating material for such equipment is consequently required to be thinner. However, under a certain DC voltage, the electric field in it becomes relatively higher according to the insulating material becomes thinner. Therefore, the insulating performance under high electric field must be important in such thin films. On the other hand, it is said that a space charge accumulation in them under DC high electric field is important because sometimes an electrical breakdown occurs in them due to an enhancement of electric field induced by the accumulated space charge. To investigate the characteristics of the space charge accumulation in them, PEA (Pulsed Electroacoustic) method is usually used. However, a spatial resolution of ordinary PEA system is not enough to observe the space charge distribution in thin films with thickness of several tens μm. Therefore, a new measurement system with high positional resolution is developed by making a thin piezo-electric film that is used as a sensor for PEA system. The obtained resolution of the developed system is 4 μm, and it is used for a typical measurement in LDPE film with thickness of 40 μm.

  4. Thin films of the Bi2Sr2Ca2Cu3O(x) superconductor

    Science.gov (United States)

    Mei, YU; Luo, H. L.; Hu, Roger

    1990-01-01

    Using RF sputtering technique, thin films of near single phase Bi2Sr2Ca2Cu3O(x) were successfully prepared on SrTiO3(100), MgO(100), and LaAlO3(012) substrates. Zero resistance of these films occurred in the range of 90-105 K.

  5. Effect of film thickness on structural and mechanical properties of AlCrN nanocompoite thin films deposited by reactive DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Ravi; Kaur, Davinder, E-mail: dkaurfph@iitr.ac.in [Functional Nanomaterial Research lab, Department of Physics and Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand (India)

    2016-05-06

    In this study, the influence of film thickness on the structural, surface morphology and mechanical properties of Aluminum chromium nitride (AlCrN) thin films has been successfully investigated. The AlCrN thin films were deposited on silicon (100) substrate using dc magnetron reactive co-sputtering at substrate temperature 400° C. The structural, surface morphology and mechanical properties were studied using X-ray diffraction, field-emission scanning electron microscopy and nanoindentation techniques respectively. The thickness of these thin films was controlled by varying the deposition time therefore increase in deposition time led to increase in film thickness. X-ray diffraction pattern of AlCrN thin films with different deposition time shows the presence of (100) and (200) orientations. The crystallite size varies in the range from 12.5 nm to 36.3 nm with the film thickness due to surface energy minimization with the higher film thickness. The hardness pattern of these AlCrN thin films follows Hall-Petch relation. The highest hardness 23.08 Gpa and young modulus 215.31 Gpa were achieved at lowest grain size of 12.5 nm.

  6. Residual stress distribution in thin diamond films and its effects on preparation of thick freestanding diamond films using DC arc plasma jet operated at gas recycling mode

    Institute of Scientific and Technical Information of China (English)

    LI Cheng-ming; LI Hui-qing; CHEN Guan-chao; L(U) Fan-xiu; TONG Yu-mei; TANG Wei-zhong

    2004-01-01

    Diamond films produced by chemical vapor deposition show excellent properties. The residual stress distribution of diamond thin films deposited by DC arc plasma jet at recycling mode was analyzed by line shifts of micro Raman spectroscopy. The results show that the compressive residual stress concentrates at the film's edge. The experimental observations show that cracks initiate at the edge of the diamond thick wafer and then propagate towards the center. The residual stress of diamond films increases with the increase of methane concentration and deposition temperature. The difference of adhesion in close area causes more shear stress and brings about the two sides of crack being not at same level. To suppress crack probability, it is favourable for increasing the film thickness and selecting a substrate with lower coefficient of thermal expansion and lower adhesion. The effects of the residual stress distribution on thick diamond films detachment were discussed.

  7. Research on film thickness of conductive line formed by laser micro-fine cladding and flexibly direct writing technique

    Institute of Scientific and Technical Information of China (English)

    Huiling Li(李慧玲); Xiaoyan Zeng(曾晓雁); Huifen Li(李惠芬); Xiangyou Li(李祥友); Yiqun Chen(陈佚群)

    2004-01-01

    The conventional technology could not fulfill the rapidly growing need for fine conductive lines for its inherent limits. Therefore, in this study laser micro-fine cladding and flexibly direct writing technique is used to obtain conductive lines with high precision and reliability. In the case of different substrates and parameters, film thickness will be different. Film thickness directly influences the reliability and stability of conductive lines with exception of quality and running speed. Therefore, we focus on developing the optimal parameters for the different substrates to achieve expected film thickness and make conductive lines have good performance and quality.

  8. Development of Low-cost Chemical and Micromechanical Sensors Based on Thick-film,Thin-film and Electroplated Films

    Institute of Scientific and Technical Information of China (English)

    Wenmin Qu; Kurt Drescher

    2000-01-01

    Various films could be used as sensing materials or as constructional materials for the fabrication of chemical and micromechanical sensors. To illustrate this potential, three sensors fabricated by very different film deposition technologies are given as examples. The sensors are a humidity sensor in thickfilm technology, a multi-functional gas sensor in thin-film technology and a three-dimensional acceleration sensor chip manufactured by electroplating techniques. Design, fabrication and characterisation of these sensors are described in this paper.

  9. A novel in-situ technique to fabricate thin films with controlled lateral thickness modulations

    Science.gov (United States)

    Zhang, Chi

    Surfaces having well-defined morphologies like periodic arrays of dots or lines, promise useful applications. Magnetic nanodots of Co and Fe-alloys are useful in patterned magnetic recording media. Well controlled grain size and surface area of nanostructured TiO2 are useful to develop efficient photocatalysts. However, there is a continuing need to develop techniques to make such surfaces in a simple and economical manner. In this thesis, a previously unexplored in-situ approach to assemble lateral patterns in thin films was proposed and investigated. Simple models of film growth on a defect free surface show that under uniform areal deposition rates and surface temperatures, nucleation occurs at random positions on the surface. We proposed that by exposing a growing thin film to a spatially varying surface temperature distribution, nucleation and growth can be confined to specific spatial locations. Consequently, a film with a desired pattern or thickness modulation could be achieved. The experimental approach consists of irradiating the substrate surface with a laser interference pattern simultaneous with physical vapor deposition (PVD). To perform such film growth experiments, a vibration minimized and multifunctional ultra-high vacuum chamber was integrated with a Nd:YAG laser. The laser output is a beam of 266 nm with a coherence length of approximately 2 m and an area of ˜0.8 x 0.8 cm2. The laser has a pulse width of 9 ns, a constant repetition rate of 50 Hz, with a rated peak output of 44 mJ/pulse. The typical laser energy density used in this work was about 10 mJ/cm2. Since sub-micron length scales were of interest, vibration studies were performed by recording the interference patterns on kapton films. Results from the kapton films, measurements using a shear accelerometer and recent growth results showed that peak-to-peak vibration amplitudes on the substrate surface were less than +/-25 nm. Well-established PVD techniques like pulsed laser deposition

  10. Enhancement of lower critical field by reducing the thickness of epitaxial and polycrystalline MgB2 thin films

    Directory of Open Access Journals (Sweden)

    Teng Tan

    2015-04-01

    Full Text Available For potential applications in superconducting RF cavities, we have investigated the properties of polycrystalline MgB2 films, including the thickness dependence of the lower critical field Hc1. MgB2 thin films were fabricated by hybrid physical-chemical vapor deposition on (0001 SiC substrate either directly (for epitaxial films or with a MgO buffer layer (for polycrystalline films. When the film thickness decreased from 300 nm to 100 nm, Hc1 at 5 K increased from around 600 Oe to 1880 Oe in epitaxial films and to 1520 Oe in polycrystalline films. The result is promising for using MgB2/MgO multilayers to enhance the vortex penetration field.

  11. Structural, optical and ac electrical characterization of CBD synthesized NiO thin films: Influence of thickness

    Science.gov (United States)

    Das, M. R.; Mukherjee, A.; Mitra, P.

    2017-09-01

    We have studied the electrical conductivity, dielectric relaxation mechanism and impedance spectroscopy characteristics of nickel oxide (NiO) thin films synthesized by chemical bath deposition (CBD) method. Thickness dependent structural, optical and ac electrical characterization has been carried out and deposition time was varied to control the thickness. The material has been characterized using X-ray diffraction and UV-VIS spectrophotometer. Impedance spectroscopy analysis confirmed enhancement of ac conductivity and dielectric constant for films deposited with higher deposition time. Decrease of grain size in thicker films were confirmed from XRD analysis and activation energy of the material for electrical charge hopping process was increased with thickness of the film. Decrease in band gap in thicker films were observed which could be associated with creation of additional energy levels in the band gap of the material. Cole-Cole plot shows contribution of both grain and grain boundary towards total resistance and capacitance. The overall resistance was found to decrease from 14.6 × 105 Ω for 30 min deposited film ( 120 nm thick) to 2.42 × 105 Ω for 120 min deposited film ( 307 nm thick). Activation energy value to electrical conduction process evaluated from conductivity data was found to decrease with thickness. Identical result was obtained from relaxation time approach suggesting hopping mechanism of charge carriers.

  12. Ferrimagnetic Tb-Fe Alloy Thin Films: Composition and Thickness Dependence of Magnetic Properties and All-Optical Switching

    Directory of Open Access Journals (Sweden)

    Birgit eHebler

    2016-02-01

    Full Text Available Ferrimagnetic rare earth - transition metal Tb-Fe alloy thin films exhibit a variety of different magnetic properties, which depends strongly on composition and temperature. In this study, first the influence of the film thickness (5 - 85 nm on the sample magnetic properties was investigated in a wide composition range between 15 at.% and 38 at.% of Tb. From our results, we find that the compensation point, remanent magnetization, and magnetic anisotropy of the Tb-Fe films depend not only on the composition but also on the thickness of the magnetic film up to a critical thickness of about 20-30 nm. Beyond this critical thickness, only slight changes in magnetic properties are observed. This behavior can be attributed to a growth-induced modification of the microstructure of the amorphous films, which affects the short range order. As a result, a more collinear alignment of the distributed magnetic moments of Tb along the out-of-plane direction with film thickness is obtained. This increasing contribution of the Tb sublattice magnetization to the total sample magnetization is equivalent to a sample becoming richer in Tb and can be referred to as an effective composition. Furthermore, the possibility of all-optical switching, where the magnetization orientation of Tb-Fe can be reversed solely by circularly polarized laser pulses, was analyzed for a broad range of compositions and film thicknesses and correlated to the underlying magnetic properties.

  13. Approximately 800-nm-Thick Pinhole-Free Perovskite Films via Facile Solvent Retarding Process for Efficient Planar Solar Cells.

    Science.gov (United States)

    Yuan, Zhongcheng; Yang, Yingguo; Wu, Zhongwei; Bai, Sai; Xu, Weidong; Song, Tao; Gao, Xingyu; Gao, Feng; Sun, Baoquan

    2016-12-21

    Device performance of organometal halide perovskite solar cells significantly depends on the quality and thickness of perovskite absorber films. However, conventional deposition methods often generate pinholes within ∼300 nm-thick perovskite films, which are detrimental to the large area device manufacture. Here we demonstrated a simple solvent retarding process to deposit uniform pinhole free perovskite films with thicknesses up to ∼800 nm. Solvent evaporation during the retarding process facilitated the components separation in the mixed halide perovskite precursors, and hence the final films exhibited pinhole free morphology and large grain sizes. In addition, the increased precursor concentration after solvent-retarding process led to thick perovskite films. Based on the uniform and thick perovskite films prepared by this convenient process, a champion device efficiency up to 16.8% was achieved. We believe that this simple deposition procedure for high quality perovskite films around micrometer thickness has a great potential in the application of large area perovskite solar cells and other optoelectronic devices.

  14. Thickness-dependent dispersion parameters, energy gap and nonlinear refractive index of ZnSe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Deo [School of Computer Science & Engineering, Faculty of Engineering, SMVD University, Kakryal, Katra 182320, J& K (India); Shaaban, E.R., E-mail: esam_ramadan2008@yahoo.com [Physics Department, Faculty of Science, Al-Azhar University, Assiut 71542 (Egypt); Shapaan, M. [Department of Physics, Faculty of Science, Al-Azahar University, Cairo (Egypt); Mohamed, S.H. [Physics Department, Faculty of Science, Sohag University, 82524 Sohag (Egypt); Othman, A.A. [Physics Department, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Verma, K.D., E-mail: kdverma1215868@gmail.com [Material Science Research Laboratory, Department of Physics, S. V. College, Aligarh 202001, U.P. (India)

    2016-08-15

    Highlights: • Combined experimental and theoretical researches on ZnSe Thin Films. • The film thickness and refractive index were determined using envelope method. • The absorption coefficient and the energy gap were calculated. • Dispersion parameters were determined using Wemple-DiDomenico relation. • The third order susceptibility and nonlinear refractive index were calculated. - Abstract: Zinc selenide (ZnSe) thin films with different thicknesses were evaporated onto glass substrates using the thermal evaporation technique. X-ray diffraction analysis confirmed that both the film and powder have cubic zinc-blende structure. The fundamental optical parameters like absorption coefficient, extinction coefficient and band gap were evaluated in transparent region of transmittance and reflectance spectrum. The optical transition of the films was found to be allowed, where the energy gap increased from 2.576 to 2.702 eV with increasing film thickness. Also, the refractive index value increase with increasing film thickness. The refractive indices evaluated through envelope method were extrapolated by Cauchy dispersion relationship over the whole spectra range. Additionally, the dispersion of refractive index was determined in terms of Wemple-DiDomenico single oscillator model. Third order susceptibility and nonlinear refractive index were determined for different thickness of ZnSe thin films.

  15. Self-assembly of monolayer-thick alumina particle-epoxy composite films.

    Science.gov (United States)

    Jackson, Bryan R; Liu, Xiangyuan; McCandlish, Elizabeth F; Riman, Richard E

    2007-11-06

    Monolayer-thick composite films composed of alpha-alumina and Spurr's epoxy were prepared via a self-assembly process known as fluid forming. The process makes use of a high-spreading-tension fluid composed of volatile and nonvolatile components to propel particles across the air-water interface within a water bath. Continuous addition of the particle suspension builds a 2D particle film at the air-water interface. The spreading fluid compresses the film into a densely packed array against a submerged substrate. The assembled monolayer is deposited onto the substrate by removing the substrate from the bath. A dispersion containing a narrow size distribution, 10 microm alpha-alumina particles, light mineral oil, and 2-propanol was spread at the air-water interface and the alumina particles were assembled into densely packed arrays with an aerial packing fraction (APF) of 0.88. However, when mineral oil was replaced by Spurr's epoxy nonuniform films with low packing density resulted. It was found that replacing 2-propanol with a mixture of 2-propanol and 1-butanol with a volume ratio of 4:1 produced uniform, densely packed alumina/epoxy composite films. The role of the solvent mixture will be discussed.

  16. Strain in epitaxial MnSi films on Si(111) in the thick film limit studied by polarization-dependent extended x-ray absorption fine structure

    Science.gov (United States)

    Figueroa, A. I.; Zhang, S. L.; Baker, A. A.; Chalasani, R.; Kohn, A.; Speller, S. C.; Gianolio, D.; Pfleiderer, C.; van der Laan, G.; Hesjedal, T.

    2016-11-01

    We report a study of the strain state of epitaxial MnSi films on Si(111) substrates in the thick film limit (100-500 Å) as a function of film thickness using polarization-dependent extended x-ray absorption fine structure (EXAFS). All films investigated are phase-pure and of high quality with a sharp interface between MnSi and Si. The investigated MnSi films are in a thickness regime where the magnetic transition temperature Tc assumes a thickness-independent enhanced value of ≥43 K as compared with that of bulk MnSi, where Tc≈29 K . A detailed refinement of the EXAFS data reveals that the Mn positions are unchanged, whereas the Si positions vary along the out-of-plane [111] direction, alternating in orientation from unit cell to unit cell. Thus, for thick MnSi films, the unit cell volume is essentially that of bulk MnSi—except in the vicinity of the interface with the Si substrate (thin film limit). In view of the enhanced magnetic transition temperature we conclude that the mere presence of the interface, and its specific characteristics, strongly affects the magnetic properties of the entire MnSi film, even far from the interface. Our analysis provides invaluable information about the local strain at the MnSi/Si(111) interface. The presented methodology of polarization dependent EXAFS can also be employed to investigate the local structure of other interesting interfaces.

  17. Thickness effect on laser-induced-damage threshold of indium-tin oxide films at 1064 nm

    Energy Technology Data Exchange (ETDEWEB)

    Wang Haifeng; Huang Zhimeng; Zhang Dayong; Luo Fei; Huang Lixian; Li Yanglong; Luo Yongquan; Wang Weiping; Zhao Xiangjie [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China)

    2011-12-01

    Laser-induced-damage characteristics of commercial indium-tin oxide (ITO) films deposited by DC magnetron sputtering deposition on K9 glass substrates as a function of the film thickness have been studied at 1064 nm with a 10 ns laser pulse in the 1-on-1 mode, and the various mechanisms for thickness effect on laser-induced-damage threshold (LIDT) of the film have been discussed in detail. It is observed that laser-damage-resistance of ITO film shows dramatic thickness effect with the LIDT of the 50-nm ITO film 7.6 times as large as the value of 300 nm film, and the effect of depressed carrier density by decreasing the film thickness is demonstrated to be the primary reason. Our experiment findings indicate that searching transparent conductive oxide (TCO) film with low carrier density and high carrier mobility is an efficient technique to improve the laser-damage-resistance of TCO films based on maintaining their well electric conductivity.

  18. Electrical and Gas Sensing Properties of SnO2 Thick Film Resistors Prepared by Screen-printing Method

    Directory of Open Access Journals (Sweden)

    R. Y. BORSE

    2008-10-01

    Full Text Available Thick films of tin-oxide (SnO2 were deposited on alumina substrates employing screen-printing technique. The films were dried and fired at 680 0C for 30 minutes. The variation of D.C. resistance of thick films was measured in air as well as in H2S gas atmosphere as a function of temperature. The SnO2 films exhibit semiconducting behaviour. The SnO2 thick films studied were also showing decrease in resistance with increase of concentration of H2S gas. The film resistors showed the highest sensitivity to H2S gas at 350 0C. The XRD studies of the thick film indicate the presence of different phases of SnO2. The elemental analysis was confirmed by EDX spectra. The surface morphological study of the films was analyzed by SEM. The microstructure of the films was porous resulting from loosely interconnected small crystallites. The parameters such as grain size, activation energy, sensitivity and response time were described.

  19. Growth and transport features of electron-doped superconductor Pr1-xLaCexCuO4-δ thin films

    Institute of Scientific and Technical Information of China (English)

    Gao Li-Juan; Jin Kui; Zhao Li; Wu Bin-Xin; Li Wei-Yong; Zhu Bei-Yi; Cao Li-Xin; Xu Bo; Qiu Xiang-Gang; Zhao Bai-Ru

    2009-01-01

    T'-phase electron-doped superconductor Pr1-xLaCexCuO4-δ (PLCCO) thin films are successfully prepared on SrTiO3 (100) substrates by using the dc magnetron sputtering method. It is found that the films each have a highly oriented structure along the c-axis. For optimally doped films with x ≈ 0.10, the superconducting transition temperature Tc is 23.5 K, which is similar to that of a single crystal. The quadratic temperature depcndence of the resistivity is observed when T Tc, which can be attributed to the two-dimensional Fermi liquid behaviour. Besides, the optimal conditions for preparing the T'-phase PLCCO thin films are also discussed in detail.

  20. Dependence of Photovoltaic Property of ZnO/Si Heterojunction Solar Cell on Thickness of ZnO Films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-Ying; ZHONG Sheng; SUN Li-Jie; FU Zhu-Xi

    2008-01-01

    N-ZnO/p-Si heterojunctions are prepared by sputtering deposition of intrinsic ZnO films on p-Si substrates.Thicknesses of ZnO films are altered by varying the deposition time from I h to 3 h.The electrical properties of these structures are analysed from capacitance-voltage ( C- V) and current-voltage (I- V) characteristics performed in a dark room.The results demonstrated that all the samples show strong rectifying behaviour.Photovoltalc property for the samples with different thicknesses of ZnO films are investigated by measuring open circuit voltage and short circuit current.It is found that photovoltages are kept to be almost constant of 32OmV along with the thickness while photocurrents changing a lot.The variation mechanism of the photovoltalc effect as a function of thickness of ZnO films is investigated.

  1. Facile production of thermoelectric bismuth telluride thick films in the presence of polyvinyl alcohol.

    Science.gov (United States)

    Lei, C; Burton, M R; Nandhakumar, I S

    2016-06-01

    Bismuth telluride is currently the best performing thermoelectric material for room temperature operations in commercial thermoelectric devices. We report the reproducible and facile production of 600 micron thick bismuth telluride (Bi2Te3) layers by low cost and room temperature pulsed and potentiostatic electrodeposition from a solution containing bismuth and tellurium dioxide in 2 M nitric acid onto nickel in the presence of polyvinyl alcohol (PVA). This was added to the electrolyte to promote thick layer formation and its effect on the structure, morphology and composition of the electrodeposits was investigated by SEM and EDX. Well adherent, uniform, compact and stoichiometric n-type Bi2Te3 films with a high Seebeck coefficient of up to -200 μV K(-1) and a high electrical conductivity of up to 400 S cm(-1) resulting in a power factor of 1.6 × 10(-3) W m(-1) K(-2) at film growth rates of 100 μm h(-1) for potentiostatic electrodeposition were obtained. The films also exhibited a well defined hexagonal structure as determined by XRD.

  2. Thickness-dependent structural arrangement in nano-confined imidazolium-based ionic liquid films.

    Science.gov (United States)

    Rouha, Michael; Cummings, Peter T

    2015-02-14

    A fundamental understanding of interfacial processes in nano-confined ionic liquids is crucial to increase the performance of modern energy storage devices. It is well-known that interfaces between electrodes and ionic liquids exhibit structures distinct from that of the bulk liquid. Following the recent interest in these systems, we studied the structure of thin ionic liquid films confined in flexible uncharged carbon nano-pores by using fully-atomistic molecular dynamics simulations. We show that the interfacial ions self-assemble into a closely-packed chequerboard-like pattern, formed by both cations and anions in direct contact with the pore wall, and that within this structure we find changes dependent on the thickness of the confined films. At low coverages a dense layer is formed in which both the imidazolium-ring and its alkyl-tail lie parallel to the pore wall. With increasing coverage the alkyl-chains reorient perpendicular to the surface, making space for additional ions until a densified highly ordered layer is formed. This wall-induced self-patterning into interfacial layers with significantly higher than bulk density is consistent with recent experimental and theoretical studies of similar systems. This work reveals additional molecular-level details on the effect of the film-thickness on the structure and density of the ionic liquid.

  3. Enhanced heat transfer is dependent on thickness of graphene films: the heat dissipation during boiling

    Science.gov (United States)

    Ahn, Ho Seon; Kim, Jin Man; Kim, TaeJoo; Park, Su Cheong; Kim, Ji Min; Park, Youngjae; Yu, Dong In; Hwang, Kyoung Won; Jo, HangJin; Park, Hyun Sun; Kim, Hyungdae; Kim, Moo Hwan

    2014-01-01

    Boiling heat transfer (BHT) is a particularly efficient heat transport method because of the latent heat associated with the process. However, the efficiency of BHT decreases significantly with increasing wall temperature when the critical heat flux (CHF) is reached. Graphene has received much recent research attention for applications in thermal engineering due to its large thermal conductivity. In this study, graphene films of various thicknesses were deposited on a heated surface, and enhancements of BHT and CHF were investigated via pool-boiling experiments. In contrast to the well-known surface effects, including improved wettability and liquid spreading due to micron- and nanometer-scale structures, nanometer-scale folded edges of graphene films provided a clue of BHT improvement and only the thermal conductivity of the graphene layer could explain the dependence of the CHF on the thickness. The large thermal conductivity of the graphene films inhibited the formation of hot spots, thereby increasing the CHF. Finally, the provided empirical model could be suitable for prediction of CHF. PMID:25182076

  4. Enhanced heat transfer is dependent on thickness of graphene films: the heat dissipation during boiling.

    Science.gov (United States)

    Ahn, Ho Seon; Kim, Jin Man; Kim, TaeJoo; Park, Su Cheong; Kim, Ji Min; Park, Youngjae; Yu, Dong In; Hwang, Kyoung Won; Jo, HangJin; Park, Hyun Sun; Kim, Hyungdae; Kim, Moo Hwan

    2014-09-03

    Boiling heat transfer (BHT) is a particularly efficient heat transport method because of the latent heat associated with the process. However, the efficiency of BHT decreases significantly with increasing wall temperature when the critical heat flux (CHF) is reached. Graphene has received much recent research attention for applications in thermal engineering due to its large thermal conductivity. In this study, graphene films of various thicknesses were deposited on a heated surface, and enhancements of BHT and CHF were investigated via pool-boiling experiments. In contrast to the well-known surface effects, including improved wettability and liquid spreading due to micron- and nanometer-scale structures, nanometer-scale folded edges of graphene films provided a clue of BHT improvement and only the thermal conductivity of the graphene layer could explain the dependence of the CHF on the thickness. The large thermal conductivity of the graphene films inhibited the formation of hot spots, thereby increasing the CHF. Finally, the provided empirical model could be suitable for prediction of CHF.

  5. Growth of thick MgB{sub 2} films by impinging-jet hybrid physical-chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lamborn, D.R. [Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Wilke, R.H.T.; Li, Q. [Department of Physics, The Pennsylvania State University, University Park, PA 16802 (United States); Xi, X. [Department of Physics, Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA 16801 (United States); Snyder, D.W. [Applied Research Laboratory, The Pennsylvania State University, University Park, PA 16802 (United States); Redwing, J.M. [Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA 16801 (United States)

    2008-01-18

    Thick MgB{sub 2} films are grown using a novel impinging-jet hybrid physical-chemical vapor deposition process. An increased amount of the boron source gas generates high growth rates. Superconducting properties of the thick films are comparable to previous results from other processes, which indicate that this is a promising new process for MgB{sub 2} deposition for coated conductor applications, such as wires and tapes for MRI magnets. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  6. Effect of finite magnetic film thickness on Néel coupling in spin valves

    Science.gov (United States)

    Kools, J. C. S.; Kula, W.; Mauri, Daniele; Lin, Tsann

    1999-04-01

    Spin valves are widely studied due to their application as magnetoresistive material in magnetic recording heads and other magnetic field sensors. An important film property is the interlayer coupling field (called offset field Ho or ferromagnetic coupling field Hf). It has been shown that the Néel model for orange-peel coupling can be applied successfully to describe this interlayer coupling. The waviness associated with the developing granular structure is thereby taken as the relevant waviness. The original Néel model describes the ferromagnetic magnetostatic interaction between two ferromagnetic layers, of infinite thickness, separated by a nonmagnetic spacer with a correlated interface waviness. In this article, this physical picture is refined to account for the effect of the finite thickness of the magnetic films in a spin valve. Magnetic poles created at the outer surfaces of the magnetic layers result in an antiferromagnetic interaction with the poles at the inner surface of the opposite layer. A simple model is presented for the different interactions in a top spin valve (columnar structure with cumulative waviness on a flat substrate) and for a bottom spin valve (columnar structure with conformal waviness on a way substrate). Comparison to experimental data, shows that the free and pinned layer thickness dependence can be understood from this refined picture.

  7. Electrodynamics of Metallic Superconductors

    Directory of Open Access Journals (Sweden)

    M. Dressel

    2013-01-01

    Full Text Available The theoretical and experimental aspects of the microwave, terahertz, and infrared properties of superconductors are discussed. Electrodynamics can provide information about the superconducting condensate as well as about the quasiparticles. The aim is to understand the frequency dependence of the complex conductivity, the change with temperature and time, and its dependence on material parameters. We confine ourselves to conventional metallic superconductors, in particular, Nb and related nitrides and review the seminal papers but also highlight latest developments and recent experimental achievements. The possibility to produce well-defined thin films of metallic superconductors that can be tuned in their properties allows the exploration of fundamental issues, such as the superconductor-insulator transition; furthermore it provides the basis for the development of novel and advanced applications, for instance, superconducting single-photon detectors.

  8. The thickness optimization of the magnet and superconductor in HTS maglev system%单块磁悬浮系统磁体和超导体的厚度优化

    Institute of Scientific and Technical Information of China (English)

    付志方; 赵立峰; 马家庆; 张勇; 赵勇

    2013-01-01

    The effect of thickness of magnets and YBCO superconductor bulks on suspended force was studied in this paper. Levitation forces of superconductor bulks with different thickness above magnets of φ>30mm × 18mm and φ30mm × 10mm were examined , respectively. The optimal values of the thickness of the magnet and superconductor bulks were thus obtained. Furthermore , vibration responses of the levitation systems mentioned above were also studied, and the best combination of magnet and superconductor bulk was obtained according to spectrum analysis.%研究了磁铁厚度和YBCO超导体厚度对悬浮力的大小及系统动态特性的影响,通过分析得出磁悬浮系统中磁体和超导体厚度的最优值.通过悬浮力测试系统测得超导块尺寸为φ30mm×18mm时四块不同厚度的磁体的悬浮力以及磁体尺寸为φ30mm × 10mm时六块不同厚度的YBCO超导体的悬浮力的大小;并在振动实验台上测试了上述情况下的振动特性.对动态曲线进行频谱分析,最终得出最优组合,从而对磁悬浮系统的磁体和超导体厚度进行了优化.

  9. Influence of La-Mn-Al Co-Doping on Dielectric Properties and Structure of BST Thick Film

    Institute of Scientific and Technical Information of China (English)

    Mao-Yan Fan; Sheng-Lin Jiang

    2009-01-01

    A new sol-gel process is applied to fabricate the BST (BaxSr1(xTiO3) sol and nano-powder of La-Mn-Al co-doping with Ba/Sr ratio 65/35, and the BST thick film is prepared in the Pt/Ti/SiO2/Si substrate. The powder and thick film are characterized by X-ray diffraction and transmission electron microscope. The influence of La-Mn-Al co-doping on the dielectric properties and micro-structure of BST thick film is analyzed. The results show that the La, Mn, and Al ions can take an obvious restraint on the growth of BaSrTiO3 grains. The polycrystalline particles come into being during the crystallization of thick film, which may improve the uniformity and compactness of thick film. The influence of unequal-valence and doping amount on the leakage current, dielectric loss, and dielectric property are mainly discussed. The dielectric constant and dielectric loss of thick film are 1200 and 0.03, respectively, in the case of 1mol% La doping, 2mol% Mn doping, and 1mol% Al doping.

  10. Investigation of thickness uniformity of thin metal films by using α-particle energy loss method and successive scanning measurements

    Science.gov (United States)

    Li, Gang; Xu, Jiayun; Bai, Lixin

    2017-03-01

    The metal films are widely used in the Inertial Confinement Fusion (ICF) experiments to obtain the radiation opacity, and the accuracy of the measuring results mainly depends on the accuracy of the film thickness and thickness uniformity. The traditional used measuring methods all have various disadvantages, the optical method and stylus method cannot provide mass thickness which reflects the internal density distribution of the films, and the weighing method cannot provide the uniformity of the thickness distribution. This paper describes a new method which combines the α-particle energy loss (AEL) method and the successive scanning measurements to obtain the film thickness and thickness uniformity. The measuring system was partly installed in the vacuum chamber, and the relationship of chamber pressure and energy loss caused by the residual air in the vacuum chamber was studied for the source-to-detector distance ranging from 1 to 5 cm. The results show that the chamber pressure should be less than 10 Pa for the present measuring system. In the process of measurement, the energy spectrum of α-particles transmitted through each different measuring point were obtained, and then recorded automatically by a self-developed multi-channel analysis software. At the same time, the central channel numbers of the spectrum (CH) were also saved in a text form document. In order to realize the automation of data processing and represent the thickness uniformity visually in a graphic 3D plot, a software package was developed to convert the CH values into film thickness and thickness uniformity. The results obtained in this paper make the film thickness uniformity measurements more accurate and efficient in the ICF experiments.

  11. Impedance of nanometer thickness ferromagnetic Co40Fe40B20 films

    Directory of Open Access Journals (Sweden)

    Lo Chi

    2011-01-01

    Full Text Available Abstract Nanocrystalline Co40Fe40B20 films, with film thickness t f = 100 nm, were deposited on glass substrates by the magnetron sputtering method at room temperature. During the film deposition period, a dc magnetic field, h = 40 Oe, was applied to introduce an easy axis for each film sample: one with h||L and the other with h||w, where L and w are the length and width of the film. Ferromagnetic resonance (FMR, ultrahigh frequency impedance (IM, dc electrical resistivity (ρ, and magnetic hysteresis loops (MHL of these films were studied. From the MHL and r measurements, we obtain saturation magnetization 4πMs = 15.5 kG, anisotropy field H k = 0.031 kG, and r = 168 mW.cm. From FMR, we can determine the Kittel mode ferromagnetic resonance (FMR-K frequency f FMRK = 1,963 MHz. In the h||L case, IM spectra show the quasi-Kittel-mode ferromagnetic resonance (QFMR-K at f 0 and the Walker-mode ferromagnetic resonance (FMR-W at fn , where n = 1, 2, 3, and 4. In the h||w case, IM spectra show QFMR-K at F 0 and FMR-W at Fn . We find that f 0 and F 0 are shifted from f FMRK, respectively, and fn = Fn . The in-plane spin-wave resonances are responsible for those relative shifts. PACS No. 76.50.+q; 84.37.+q; 75.70.-i

  12. Variation of structure and magnetic properties with thickness of thin Co59Fe26Ni15 films

    NARCIS (Netherlands)

    Chechenin, NG; van Voorthuysen, EHD; De Hosson, JTM; Boerma, DO

    2005-01-01

    Variations of phase composition and magnetic properties of electrodeposited nanocrystalline Co-Fe-Ni films with film thickness in the range of 50-500 nm were analyzed. The samples were magnetically soft with coercivity in the range H-c = 2-20 Oe and uni axial magnetic anisotropy up to H-k = 20 Oe. I

  13. Ab initio analytical model of light transmission through a cylindrical subwavelength hole in an optically thick film

    DEFF Research Database (Denmark)

    Bordo, Vladimir

    2011-01-01

    The rigorous analytical theory of light transmission through a cylindrical hole of arbitrary diameter in an optically thick film is developed. The approach is based on the introduction of fictitious surface currents at both hole openings and both film surfaces. The solution of Maxwell’s equations...

  14. Thickness-dependent structure and properties of SnS2 thin films prepared by atomic layer deposition

    Science.gov (United States)

    Seo, Wondeok; Shin, Seokyoon; Ham, Giyul; Lee, Juhyun; Lee, Seungjin; Choi, Hyeongsu; Jeon, Hyeongtag

    2017-03-01

    Tin disulfide (SnS2) thin films were deposited by a thermal atomic layer deposition (ALD) method at low temperatures. The physical, chemical, and electrical characteristics of SnS2 were investigated as a function of the film thickness. SnS2 exhibited a (001) hexagonal plane peak at 14.9° in the X-ray diffraction (XRD) results and an A1g peak at 311 cm‑1 in the Raman spectra. These results demonstrate that SnS2 thin films grown at 150 °C showed a crystalline phase at film thicknesses above 11.2 nm. The crystallinity of the SnS2 thin films was evaluated by a transmission electron microscope (TEM). The X-ray photoelectron spectroscopy (XPS) analysis revealed that SnS2 consisted of Sn4+ and S2‑ valence states. Both the optical band gap and the transmittance of SnS2 decreased as the film thickness increased. The band gap of SnS2 decreased from 3.0 to 2.4 eV and the transmittance decreased from 85 to 32% at a wavelength of 400 nm. In addition, the resistivity of the thin film SnS2 decreased from 1011 to 106 Ω·cm as the film thickness increased.

  15. Microstructure and thermoelectric properties of screen-printed thick-films of misfit-layered cobalt oxides with Ag addition

    DEFF Research Database (Denmark)

    Van Nong, Ngo; Samson, Alfred Junio; Pryds, Nini

    2012-01-01

    Thermoelectric properties of thick (~60 μm) films prepared by a screen-printing technique using p-type misfit-layered cobalt oxide Ca3Co4O9+δ with Ag addition have been studied. The screen-printed films were sintered in air at various temperatures ranging from 973 K to 1223 K. After each sintering...

  16. Coupling effects in bilayer thick metal films perforated with rectangular nanohole arrays

    Directory of Open Access Journals (Sweden)

    Li Yuan

    2013-09-01

    Full Text Available The coupling effects in bilayer thick metal (silver films perforated with rectangular nanohole arrays are investigated using the finite-difference time-domain technique. Many interesting light phenomena are observed as the distance between the metal rectangular nanohole arrays varies. Coupling effects are found to play very important roles on the optical and electronic properties of bilayer metal rectangular nanohole arrays: antisymmetric coupling between surface plasmon polaritons near the top and bottom film plane, and antisymmetric coupling between localized surface plasmon resonances near the two long sides of the rectangular hole, are probably excited in each layer of bilayer metal rectangular nanohole arrays; antisymmetric and symmetric magnetic coupling probably occur between the metal rectangular nanohole arrays.

  17. Wet Chemical Synthesis and Screening of Thick Porous Oxide Films for Resistive Gas Sensing Applications

    Directory of Open Access Journals (Sweden)

    Wilhelm F. Maier

    2006-11-01

    Full Text Available A method of wet chemical synthesis suitable for high throughput and combinatorial applications has been developed for the synthesis of porous resistive thick-film gas sensors. This method is based on the robot-controlled application of unstable metal oxide suspensions on an array of 64 inter-digital electrodes positioned on an Al2O3 substrate. SnO2, WO3, ZrO2, TiO2, CeO2, In2O3 and Bi2O3 were chosen as base oxides, and were optimised by doping or mixed oxide formation. The parallel synthesis of mixed oxide sensors is illustrated by representative examples. The electrical characteristics and the sensor performance of the films were measured by high-throughput impedance spectroscopy while supplying various test gases (H2, CO, NO, NO2, propene. Data collection, data mining techniques applied and the best potential sensor materials discovered are presented.

  18. Residual Strains in a Nanometer Thick Cr Film Measured on Micromachined Beams

    Institute of Scientific and Technical Information of China (English)

    Z.M. Zhou; Yong Zhou; Ying Cao; Haiping Mao

    2009-01-01

    A Cr film with a 75 nm thickness sputtered on a Si substrate was used to fabricate microbridge and microcan-tilever samples with the MEMS (microelectromechanical system) technique. The profile of the buckled beams was measured by using the interference technique with white light and fitted with a theoretical result. The uniform residual strain in the bridge samples was deduced from the variation of buckling amplitude with the beam length. On the other hand, the gradient residual strain was determined from the deflection profile of the cantilever. The residual uniform and gradient strain in the Cr film are about 4.96×10-3 and 4.2967×10-5, respectively.

  19. 100-nm thick single-phase wurtzite BAlN films with boron contents over 10%

    KAUST Repository

    Li, Xiaohang

    2017-01-11

    Growing thicker BAlN films while maintaining single-phase wurtzite structure and boron content over 10% has been challenging. In this study, we report on the growth of 100 nm-thick single-phase wurtzite BAlN films with boron contents up to 14.4% by MOCVD. Flow-modulated epitaxy was employed to increase diffusion length of group-III atoms and reduce parasitic reactions between the metalorganics and NH3. A large growth efficiency of ∼2000 μm mol−1 was achieved as a result. Small B/III ratios up to 17% in conjunction with high temperatures up to 1010 °C were utilized to prevent formation of the cubic phase and maintain wurtzite structure.

  20. Quasiparticle Transport in Thick Aluminum Films Coupled to Tungsten Transition Edge Sensors

    Science.gov (United States)

    Yen, J. J.; Kreikebaum, J. M.; Young, B. A.; Cabrera, B.; Moffatt, R.; Redl, P.; Shank, B.; Brink, P. L.; Cherry, M.; Tomada, A.

    2016-07-01

    We have fabricated and characterized test devices of a new geometry for cryogenic dark matter search superconducting sensors. The modified design uses the same photolithography masks used to fabricate earlier-generation devices, but with the Al and W films deposited in reverse order. This inverted film geometry (Al over W instead of our conventional W over Al) offers a simplified and robust way to dramatically increase the thickness of Al energy-collecting fins coupled to thin W-TESs—tungsten-transition edge sensors. Data are presented from experiments with inverted geometry test devices exposed to X-rays from a NaCl fluorescence source. The results are compared to data obtained with similar devices fabricated in the standard, non-inverted geometry.

  1. Degradation of PVC/rPLA Thick Films in Soil Burial Experiment

    Science.gov (United States)

    Nowak, Bożena; Rusinowski, Szymon; Chmielnicki, Blazej; Kamińska-Bach, Grażyna; Bortel, Krzysztof

    2016-10-01

    Some of the biodegradable polymers can be blended with a synthetic polymer to facilitate their biodegradation in the environment. The objective of the study was to investigate the biodegradation of thick films of poly(vinyl chloride)/recycled polylactide (PVC/rPLA). The experiments were carried out in the garden soil or in the mixture of garden soil and hydrocarbon-contaminated soil under laboratory conditions. Since it is widely accepted that the biosurfactants secreted by microorganisms enable biotransformation of various hydrophobic substances in the environment, it was assumed that the use of contaminated soil, rich in biosurfactant producing bacteria, may accelerate biodegradation of plastics. After the experimental period, the more noticeable weight loss of polymer films was observed after incubation in the garden soil. However, more pronounced changes in the film surface morphology and chemical structure as well as decrease of tensile strength were observed after incubation of films in the mixture of garden and contaminated soil. It turned out that as a result of competition between two distinct groups of microorganisms present in the mixture of garden and hydrocarbon-contaminated soils the number of microorganisms and their activity were lower than the activity of indigenous microflora of garden soil as well as the amount of secreted biosurfactants towards plastics.

  2. Effect of Ti layer thickness on microstructure and magnetic properties of Ti/Co/Ti films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yujie; ZHANG Hanwei; FENG Shunzhen; SUN Huiyuan; HU Yanying; PENG Yan

    2006-01-01

    TiCoTi granular films were prepared by DC facing-target magnetron sputtering system onto glass substrates and subsequently in situ annealing in vacuum. Structural of Ti ( t nm)/Co (40 nm)/Ti ( t nm) films were investigated in detail, which shows that the majority Co nanograins are formed as the hexagonal-close-packed (HCP) structure. Vibrating sample magnetometer (VSM) and scanning probe microscope (SPM) were applied to study the magnetic properties, morphologies and domain structures of these samples. It has been found that the structure and magnetic properties of the Ti/Co/Ti films depend strongly on the Ti layer thickness. The out-of-plane coercivities ( Hc) of the film is maximum about 78.8 kA·m-1 when t =5 nm with annealing at 300 ℃; the distributing of grains of the sample is uniformity; and the average size of particles is about 13 nm. The obtained results suggest that this system is perpendicular anisotropy and might be applicable to perpendicular magnetic recording media.

  3. Effect of Channel Layer Thickness on Characteristics and Stability of Amorphous Hafnium-Indium-Zinc Oxide Thin Film Transistors

    Science.gov (United States)

    Kim, Sun-Jae; Lee, Soo-Yeon; Lee, Young-Wook; Lee, Woo-Geun; Yoon, Kap-Soo; Kwon, Jang-Yeon; Han, Min-Koo

    2011-02-01

    We investigated the channel layer thickness dependence of the characteristics and stability in amorphous hafnium indium zinc-oxide (HIZO) thin film transistors (TFTs). HIZO TFTs were prepared with various channel thicknesses from 400 to 700 Å. In HIZO TFTs, carrier concentration is considerably high, which leads to channel layer thickness dependence. The threshold voltages of TFTs negatively shifted as the channel thickness increased. The threshold voltage shift at a high temperature is more severe in TFTs with thicker channel layers. The channel thickness dependence of the bias stability of HIZO TFTs is closely related to the back interface, rather than the bulk state.

  4. Critical thickness and orbital ordering in ultrathin La0.7Sr0.3MnO3 films

    NARCIS (Netherlands)

    Huijben, M.; Martin, L.W.; Chu, Y.-H.; Holcomb, M.B.; Yu, P.; Rijnders, G.; Blank, D.H.A.; Ramesh, R.

    2008-01-01

    Detailed analysis of transport, magnetism, and x-ray absorption spectroscopy measurements on ultrathin La0.7Sr0.3MnO3 films with thicknesses from 3 to 70 unit cells resulted in the identification of a lower critical thickness for a nonmetallic nonferromagnetic layer at the interface with the SrTiO3

  5. A Ceramic Thick Film Humidity Sensor Based on MnZn Ferrite

    Directory of Open Access Journals (Sweden)

    D. Egan

    2002-02-01

    Full Text Available A ceramic thick film humidity sensor, produced from MnZn ferrite, is presented. The proposed sensing mechanism is a combination of proton hopping, hydronium diffusion, and vacancy donor traps releasing electrons into the conduction band. The sensor structure comprises a two-layer device; the first layer is an interdigitated conductor and the second layer is a 30μm thick sensing layer. The effects of sintering the sensing pastes in air and vacuum have been reported. The air-fired sample exhibits the highest humidity sensitivity (1.54%/RH% and the lowest temperature sensitivity (0.37%/oC. The vacuum-fired sample has the lowest humidity sensitivity (0.043%/RH and the highest temperature sensitivity (0.77%/oC. The sensitivity results indicate that the air-fired sample has the best potential for use in humidity sensing applications.

  6. CdS nanofilms: Effect of film thickness on morphology and optical band gap

    Science.gov (United States)

    Kumar, Suresh; Kumar, Santosh; Sharma, Pankaj; Sharma, Vineet; Katyal, S. C.

    2012-12-01

    CdS nanofilms of varying thickness (t) deposited by chemical bath deposition technique have been studied for structural changes using x-ray diffractometer (XRD) and transmission electron microscope (TEM). XRD analysis shows polycrystalline nature in deposited films with preferred orientation along (002) reflection plane also confirmed by selected area diffraction pattern of TEM. Uniform and smooth surface morphology observed using field emission scanning electron microscope. The surface topography has been studied using atomic force microscope. The optical constants have been calculated from the analysis of %T and %R spectra in the wavelength range 300 nm-900 nm. CdS nanofilms show a direct transition with red shift. The optical band gap decreases while the refractive index increases with increase in thickness of nanofilms.

  7. Deep Impact Delta II Launch Vehicle Cracked Thick Film Coating on Electronic Packages Technical Consultation Report

    Science.gov (United States)

    Cameron, Kenneth D.; Kichak, Robert A.; Piascik, Robert S.; Leidecker, Henning W.; Wilson, Timmy R.

    2009-01-01

    The Deep Impact spacecraft was launched on a Boeing Delta II rocket from Cape Canaveral Air Force Station (CCAFS) on January 12, 2005. Prior to the launch, the Director of the Office of Safety and Mission Assurance (OS&MA) requested the NASA Engineering and Safety Center (NESC) lead a team to render an independent opinion on the rationale for flight and the risk code assignments for the hazard of cracked Thick Film Assemblies (TFAs) in the E-packages of the Delta II launch vehicle for the Deep Impact Mission. The results of the evaluation are contained in this report.

  8. A low-cost photovoltaic cell process based on thick film techniques

    Science.gov (United States)

    Mardesich, N.; Pepe, A.; Bunyan, S.; Edwards, B.; Olson, C.

    1980-01-01

    The low-cost, easily automated processing for solar cell fabrication being developed at Spectrolab for the DOE LSA program is described. These processes include plasma-etching, spray-on diffusion sources and antireflective coating, thick film metallization, aluminum back contacts, laser scribing and ultrasonic soldering. The process sequence has been shown to produce solar cells having 15% conversion efficiency at AM1 which meet the cell fabrication budget required for the DOE 1986 cost goal of $0.70 per peak watt in 1980.

  9. Nonlinear thickness-stretch vibration of thin-film acoustic wave resonators

    Science.gov (United States)

    Ji, Xiaojun; Fan, Yanping; Han, Tao; Cai, Ping

    2016-03-01

    We perform a theoretical analysis on nonlinear thickness-stretch free vibration of thin-film acoustic wave resonators made from AlN and ZnO. The third-order or cubic nonlinear theory by Tiersten is employed. Using Green's identify, under the usual approximation of neglecting higher time harmonics, a perturbation analysis is performed from which the resonator frequency-amplitude relation is obtained. Numerical calculations are made. The relation can be used to determine the linear operating range of these resonators. It can also be used to compare with future experimental results to determine the relevant thirdand/or fourth-order nonlinear elastic constants.

  10. Thick-Film Carbon Dioxide Sensor via Anodic Adsorbate Stripping Technique and Its Structural Dependence.

    Science.gov (United States)

    Photinon, Kanokorn; Wang, Shih-Han; Liu, Chung-Chiun

    2009-01-01

    A three-electrode based CO(2) sensor was fabricated using thick-film technology. The performance of this sensor was further enhanced by incorporating platinum nanoparticles onto the working electrode surface. An eight-fold increase in the signal output was obtained from the electrode with the platinum nanoparticles. The sensing output was linearly related to the CO(2) presented. Stability measurements demonstrated that the decline of the active surface area and the sensitivity of the sensor were 8% and 13%, respectively, over a two week period of time. The sensor response appeared to be a structural dependence of the crystallographic orientation of platinum electrode.

  11. Thick-Film Carbon Dioxide Sensor via Anodic Adsorbate Stripping Technique and Its Structural Dependence

    Directory of Open Access Journals (Sweden)

    Chung-Chiun Liu

    2009-09-01

    Full Text Available A three-electrode based CO2 sensor was fabricated using thick-film technology. The performance of this sensor was further enhanced by incorporating platinum nanoparticles onto the working electrode surface. An eight-fold increase in the signal output was obtained from the electrode with the platinum nanoparticles. The sensing output was linearly related to the CO2 presented. Stability measurements demonstrated that the decline of the active surface area and the sensitivity of the sensor were 8% and 13%, respectively, over a two week period of time. The sensor response appeared to be a structural dependence of the crystallographic orientation of platinum electrode.

  12. Screen printed PZT/PZT thick film bimorph MEMS cantilever device for vibration energy harvesting

    DEFF Research Database (Denmark)

    Xu, Ruichao; Lei, Anders; Christiansen, T.L.

    2011-01-01

    We present a MEMS-based PZT/PZT thick film bimorph vibration energy harvester with an integrated silicon proof mass. The most common piezoelectric energy harvesting devices utilize a cantilever beam of a non piezoelectric material as support beneath or in-between the piezoelectric material....... It provides mechanical support but it also reduces the power output. Our device replaces the support with another layer of the piezoelectric material, and with the absence of an inactive mechanical support all of the stresses induced by the vibrations will be harvested by the active piezoelectric elements....

  13. ALD grown nanostructured ZnO thin films: Effect of substrate temperature on thickness and energy band gap

    Directory of Open Access Journals (Sweden)

    Javed Iqbal

    2016-10-01

    Full Text Available Nanostructured ZnO thin films with high transparency have been grown on glass substrate by atomic layer deposition at various temperatures ranging from 100 °C to 300 °C. Efforts have been made to observe the effect of substrate temperature on the thickness of the deposited thin films and its consequences on the energy band gap. A remarkably high growth rate of 0.56 nm per cycle at a substrate temperature of 200 °C for ZnO thin films have been achieved. This is the maximum growth rate for ALD deposited ZnO thin films ever reported so far to the best of our knowledge. The studies of field emission scanning electron microscopy and X-ray diffractometry patterns confirm the deposition of uniform and high quality nanosturtured ZnO thin films which have a polycrystalline nature with preferential orientation along (100 plane. The thickness of the films deposited at different substrate temperatures was measured by ellipsometry and surface profiling system while the UV–visible and photoluminescence spectroscopy studies have been used to evaluate the optical properties of the respective thin films. It has been observed that the thickness of the thin film depends on the substrate temperatures which ultimately affect the optical and structural parameters of the thin films.

  14. EFFECT OF MOLECULAR WEIGHT AND FILM THICKNESS ON THE CRYSTALLIZATION AND MICROPHASE SEPARATION IN POLYSTYRENE BLOCK-POLY(L-LACTIC ACID) THIN FILMS AT THE EARLY STAGE

    Institute of Scientific and Technical Information of China (English)

    Yu-han Wei; Cai-yuan Pan; Bin-yao Li; Xin-hong Yu; Yan-chun Han

    2011-01-01

    We investigated the effects of molecular weight and film thickness on the crystallization and microphase separation in semicrystalline block copolymer polystyrene-block-poly(L-lactic acid) (PS-b-PLLA) thin films, at the early stage of film evolution (when Ts < T < TODT) by in situ hot stage atomic force microscopy. For PS-b-PLLA 1 copolymer which had lower molecular weight and higher PLLA fraction, diffusion-controlled break-out crystallization started easily.For PS-b-PLLA 2 with higher molecular weight, crystallization in nanometer scales occurs in local area. After melting of the two copolymer films, islands were observed at the film surface: PS-b-PLLA 1 film was in a disordered phase mixed state while PS-b-PLLA 2 film formed phase-separated lamellar structure paralleling to the substratc. Crystallization-melting and van der Waals forces drove the island formation in PS-b-PLLA 1 film. Film thickness affected the crystallization rate. Crystals grew very slowly in much thinner film ofPS-b-PLLA 1 and remained almost unchanged at long time annealing. The incompatibility between PS and PLLA blocks drove the film fluctuation which subsequently evolved into spinodal-like morphology.

  15. Determination of layer thickness and optical constants of thin films by using a modified pattern search method.

    Science.gov (United States)

    Miloua, R; Kebbab, Z; Chiker, F; Sahraoui, K; Khadraoui, M; Benramdane, N

    2012-02-15

    We propose the use of a pattern search optimization technique in combination with a seed preprocessing procedure to determine the optical constants and thickness of thin films using only the transmittance spectra. The approach is quite flexible, straightforward to implement, and efficient in reaching the best fitting. We demonstrate the effectiveness of the method in extracting optical constants, even when the films are not displaying interference fringes. Comparison to a real-coded genetic algorithm shows that the modified pattern search is fast, almost accurate, and does not need any parameter adjustments. The approach is successfully applied to extract the thickness and optical constants of spray pyrolyzed nanocrystalline CdO thin films.

  16. Effect of Catalyst Film Thickness on Growth Morphology, Surface Wettability and Drag Reduction Property of Carbon Nanotubes

    Science.gov (United States)

    Ma, Weiwei; Zhou, Zhiping; Li, Gang; Li, Ping

    2016-10-01

    Nickel films were deposited on silicon substrates using magnetron sputtering method. The pretreatment process of nickel films under high temperature and ammonia atmosphere was investigated. The thickness of nickel film has a great influence on growth morphology of carbon nanotubes (CNTs). Too large or too small thickness would do harm to the orientated growth of CNTs. The inner structure, elements composition and growth mechanism have been confirmed by TEM and EDX characterization. The surface wettability and drag reduction property of CNTs were investigated. This paper can provide a new, effective method to further develop the practical application in micro/nano devices field.

  17. Thermal Conductivity Measurement of Submicron-Thick Aluminium Oxide Thin Films by a Transient Thermo-Reflectance Technique

    Institute of Scientific and Technical Information of China (English)

    BAI Su-Yuan; TANG Zhen-An; HUANG Zheng-Xing; YU Jun; WANG Jia-Qi

    2008-01-01

    Thermal conductivity of submicron-thick aluminium oxide thin films prepared by middle frequency magnetron sputtering is measured using a transient thermo-reflectance technique.A three-layer model based on transmission line theory and the gentic algorithm optimization method are employed to obtain the thermal conductivity of thin films and the interfacial thermal resistance.The results show that the average thermal conductivity of 3301000nm aluminium oxide thin films is 3.3Wm-1 K-1 at room temperature.No significant thickness dependence is found.The uncertainty of the measurement is less than 10%.

  18. Lightning in superconductors.

    Science.gov (United States)

    Vestgården, J I; Shantsev, D V; Galperin, Y M; Johansen, T H

    2012-01-01

    Crucially important for application of type-II superconductor films is the stability of the vortex matter--magnetic flux lines penetrating the material. If some vortices get detached from pinning centres, the energy dissipated by their motion will facilitate further depinning, and may trigger a massive electromagnetic breakdown. Up to now, the time-resolved behaviour of these ultra-fast events was essentially unknown. We report numerical simulation results revealing the detailed dynamics during breakdown as within nanoseconds it develops branching structures in the electromagnetic fields and temperature, with striking resemblance of atmospheric lightning. During a dendritic avalanche the superconductor is locally heated above its critical temperature, while electrical fields rise to several kV/m as the front propagates at instant speeds near up to 100 km/s. The numerical approach provides an efficient framework for understanding the ultra-fast coupled non-local dynamics of electromagnetic fields and dissipation in superconductor films.

  19. Design of instantaneous liquid film thickness measurement system for conductive or non-conductive fluid with high viscosity

    Directory of Open Access Journals (Sweden)

    Yongxin Yu

    2017-06-01

    Full Text Available In the paper, a new capacitive sensor with a dielectric film coating was designed to measure the thickness of the liquid film on a flat surface. The measured medium can be conductive or non-conductive fluid with high viscosity such as silicone oil, syrup, CMC solution and melt. With the dielectric film coating, the defects caused by the humidity in a capacitor can be avoided completely. With a excitation frequency 0-20kHz, the static permittivity of capacitive sensor is obtained and stable when small thicknesses are monitored within the frequency of 0-3kHz. Based on the measurement principle, an experimental system was designed and verified including calibration and actual measurement for different liquid film thickness. Experimental results showed that the sensitivity, the resolution, repeatability and linear range of the capacitive sensor are satisfied to the liquid film thickness measurement. Finally, the capacitive measuring system was successfully applied to the water, silicone oil and syrup film thickness measurement.

  20. Anomalous thickness-dependent optical energy gap of ALD-grown ultra-thin CuO films

    Science.gov (United States)

    Tripathi, T. S.; Terasaki, I.; Karppinen, M.

    2016-11-01

    Usually an inverse square relation between the optical energy gap and the size of crystallites is observed for semiconducting materials due to the strong quantum localization effect. Coulomb attraction that may lead to a proportional dependence is often ignored or considered less important to the optical energy gap when the crystallite size or the thickness of a thin film changes. Here we report a proportional dependence between the optical energy gap and the thickness of ALD-grown CuO thin films due to a strong Coulomb attraction. The ultrathin films deposited in the thickness range of 9-81 nm show a p-type semiconducting behavior when analyzed by Seebeck coefficient and electrical resistivity measurements. The indirect optical energy gap nature of the films is verified from UV-vis spectrophotometric measurements. A progressive increase in the indirect optical energy gap from 1.06 to 1.24 eV is observed with the increase in the thickness of the films. The data are analyzed in the presence of Coulomb attractions using the Brus model. The optical energy gap when plotted against the cubic root of the thickness of the films shows a linear dependence.

  1. Structural and Optical Properties of ZnO Films with Different Thicknesses Grown on Sapphire by MOCVD

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    ZnO(002) films with different thicknesses, grown on Al2O3 (006) substrates by metal-organic chemical vapor deposition( MOCVD), were etched by Ar ion beams. The samples were examined by D8 X-ray diffraction, scanning electron microscopy(SEM), and photoluminescence (PL) spectrometry. The structural properties vary with the increasing thickness of the films. When the film thickness is thin, the phi(Φ) scanning curves for ZnO(103) and sapphire(116) substrate show the existence of two kinds of orientation relationships between ZnO films and sapphire,which are ZnO(002)//Al2O3 (006), ZnO(100)//Al2O3 (110) and ZnO(002)//Al2O3 (006), ZnO(110)//Al2O3(110). When the thickness increases to 500 nm there is only one orientation relationship, which is ZnO(002)//Al2O3 (006), ZnO [ 100 ]//Al2O3[ 110 ]. Their photoluminescence (PL) spectra at room temperature show that the optical properties of ZnO films have been greatly improved when increasing the thickness of films is increased.

  2. ZnO sensing film thickness effects on the sensitivity of surface plasmon resonance sensors with angular interrogation

    Energy Technology Data Exchange (ETDEWEB)

    Bao Ming; Li Ge; Jiang Dongmei; Cheng Wenjuan [State Key Laboratory of Precision Spectroscopy, and Department of Physics, East China Normal University, Shanghai 200062 (China); Ma Xueming, E-mail: xmma@phy.ecnu.edu.cn [State Key Laboratory of Precision Spectroscopy, and Department of Physics, East China Normal University, Shanghai 200062 (China)

    2010-07-25

    The effects of ZnO sensing film thickness on the surface plasmon resonance (SPR) curve have been investigated. ZnO sensing films with the thickness of 20 nm, 30 nm, 200 nm, 220 nm and 240 nm have been deposited onto Ag/glass substrates by radio frequency magnetron (RF) sputtering and thermally treated at 300 deg. C in air for 1 h. The surface morphology of the sample was inspected using an atomic force microscope (AFM). The refractive index of the ZnO films was extracted by using spectroscopic ellipsometry (SE). Theoretical analysis of the sensitivity of the SPR sensors with different ZnO sensing film thickness is discussed, and the experimental results are in agreement with the calculated value. Also, the theoretical calculation of the effects of ZnO film thickness on the SPR curves in the presence of different analytes are presented and studied. It is demonstrated that SPR sensors with angular interrogation may attain higher sensitivity and can detect higher surface environment refractive index with proper ZnO sensing film thickness.

  3. Low Temperature Processing of Nanocrystalline Lead Zirconate Titanate (PZT) Thick Films and Ceramics by a Modified Sol-Gel Route

    Science.gov (United States)

    Zhu, Weiguang; Wang, Zhihong; Zhao, Changlei; Tan, Ooi Kiang; Hng, Huey Hoon

    2002-11-01

    Dispersing fine particles into a sol-gel matrix is a promising process to get a thick 0-3 composite coating layer. In this paper, we have further improved this modified sol-gel process by nanocrystalline composite technique to realize the low temperature annealing. Dense Pb(Zr, Ti)O3 (PZT) thick films of 10 to 50 μm in thickness have been obtained on the platinum-coated silicon substrates by spin-coating at sintering temperature of 600-700°C and fully developed submicron-sized grains have been demonstrated in screen-printing piezoelectric films on alumina substrates at sintering temperature of 700-800°C. The dependence of various properties such as microstructure, crystallization, ferroelectric and dielectric properties of such made thick films on the processing parameters have been investigated. For a 10 μm-thick film spin-coated on silicon wafer, the dielectric loss and relative permittivity are 0.010 and 1024, respectively, at 1 kHz. The remanent polarization (Pr) and the coercive field (Ec) are 13.6 μC/cm2 and 34.5 kV/cm, respectively. Obviously, such made thick film has comparable properties with bulk PZT ceramic. This novel technique can be extensively used in sol-gel, screen-printing, tape-casting, even in traditional ceramic process to reduce the process temperature.

  4. Preparation and characterization of thin films of the superconductor FeSe

    Energy Technology Data Exchange (ETDEWEB)

    Venzmer, Eike; Kronenberg, Alexander; Haaf, Sebastian ten; Jourdan, Martin [Institut fuer Physik, Johannes Gutenberg-Universitaet, Staudingerweg 7, 55128 Mainz (Germany); Maletz, Janek [IFW-Dresden, Institute for Solid State Research, PO Box 270116, D-01171 Dresden (Germany)

    2013-07-01

    The recently discovered class of iron pnictide compounds features a presumably unconventional mechanism of superconductivity. We investigate the iron chalcogenide FeSe, which is the structurally simplest representative of this class of materials. Epitaxial thin films are prepared by rf-sputtering from a stoichiometric FeSe target and alternatively by co-sputtering from separate Fe and Se targets. Both methods yield superconducting epitaxial thin films on MgO(100) as well as on YAlO{sub 3}(010) substrates. The influence of deposition rates and substrate temperature on phase formation, sample homogeneity, morphology and electronic transport properties are discussed. A comparison with the properties of previously prepared by MBE is presented. The main advantage of the sputter deposited samples is an improved morphology which is promising for the future integration in planar tunneling junctions for spectroscopic investigations.

  5. Surface resistance of thin perovskite films - high-temperature superconductors and giant magnetoresistance manganites

    Energy Technology Data Exchange (ETDEWEB)

    Lofland, S.E. [Maryland Univ., College Park, MD (United States). Dept. of Phys.; Dominguez, M. [Maryland Univ., College Park, MD (United States). Dept. of Phys.; Tyagi, S.D. [Maryland Univ., College Park, MD (United States). Dept. of Phys.; Bhagat, S.M. [Maryland Univ., College Park, MD (United States). Dept. of Phys.; Robson, M.C. [Center for Superconductivity Research, Univ. of Maryland, College Park, MD (United States); Kwon, C. [Center for Superconductivity Research, Univ. of Maryland, College Park, MD (United States); Trajanovic, Z. [Center for Superconductivity Research, Univ. of Maryland, College Park, MD (United States); Takeuchi, I. [Center for Superconductivity Research, Univ. of Maryland, College Park, MD (United States); Ramesh, R. [Center for Superconductivity Research, Univ. of Maryland, College Park, MD (United States)]|[Dept. of Materials Research and Nuclear Engineering, Univ. of Maryland, College Park, MD (United States); Venkatesan, T. [Center for Superconductivity Research, Univ. of Maryland, College Park, MD (United States)]|[Maryland Univ., College Park, MD (United States). Dept. of Electrical Engineering

    1996-11-15

    We present a systematic study of the surface resistance of perovskite thin films and bulk samples at microwave frequencies. The d.c. resistivity {rho} of the various samples spans three orders of magnitude. For bulk samples, we obtain the usual {rho}{sup 1/2} dependence of R{sub s}. For {rho} < 1 {mu}{Omega} cm, R{sub s} displays conventional behavior, i.e. R{sub s} {proportional_to} {rho}. However, for {rho} > 1 {mu}{Omega} cm, R{sub s} is not proportional to {rho} but to the conductivity {sigma}. Using this fact, we have made the first direct observation of a peak in {sigma}{sub 1}, just below T{sub c} in a-axis films of YBa{sub 2}Cu{sub 3}O{sub 7}. (orig.)

  6. Improvement of Flame-made ZnO Nanoparticulate Thick Film Morphology for Ethanol Sensing

    Directory of Open Access Journals (Sweden)

    Sukon Phanichphant

    2007-05-01

    Full Text Available ZnO nanoparticles were produced by flame spray pyrolysis using zinc naphthenate as a precursor dissolved in toluene/acetonitrile (80/20 vol%. The particles properties were analyzed by XRD, BET. The ZnO particle size and morphology was observed by SEM and HR-TEM revealing spheroidal, hexagonal, and rod-like morphologies. The crystallite sizes of ZnO spheroidal and hexagonal particles ranged from 10-20 nm. ZnO nanorods were ranged from 10-20 nm in width and 20-50 nm in length. Sensing films were produced by mixing the nanoparticles into an organic paste composed of terpineol and ethyl cellulose as a vehicle binder. The paste was doctor-bladed onto Al2O3 substrates interdigitated with Au electrodes. The morphology of the sensing films was analyzed by optical microscopy and SEM analysis. Cracking of the sensing films during annealing process was improved by varying the heating conditions. The gas sensing of ethanol (25-250 ppm was studied at 400 °C in dry air containing SiC as the fluidized particles. The oxidation of ethanol on the surface of the semiconductor was confirmed by mass spectroscopy (MS. The effect of micro-cracks was quantitatively accounted for as a provider of extra exposed edges. The sensitivity decreased notably with increasing crack of sensing films. It can be observed that crack widths were reduced with decreasing heating rates. Crack-free of thick (5 μm ZnO films evidently showed higher sensor signal and faster response times (within seconds than cracked sensor. The sensor signal increased and the response time decreased with increasing ethanol concentration.

  7. Characterization of the optical constants and dispersion parameters of chalcogenide Te40Se30S30 thin film: thickness effect

    Science.gov (United States)

    Abd-Elrahman, M. I.; Hafiz, M. M.; Qasem, Ammar; Abdel-Rahim, M. A.

    2016-02-01

    Chalcogenide Te40Se30S30 thin films of different thickness (100-450 nm) are prepared by thermal evaporation of the Te40Se30S30 bulk. X-ray examination of the film shows some prominent peaks relate to crystalline phases indicating the crystallization process. The calculated particles of crystals from the X-ray diffraction peaks are found to be from 11 to 26 nm. As the thickness increases, the transmittance decreases and the reflectance increases. This could be attributed to the increment of the absorption of photons as more states will be available for absorbance in the case of thicker films. The decrease in the direct band gap with thickness is accompanied with an increase in energy of localized states. The obtained data for the refractive index could be fit to the dispersion model based on the single oscillator equation. The single-oscillator energy decreases, while the dispersion energy increases as the thickness increases.

  8. Thick-film force, slip and temperature sensors for a prosthetic hand

    Science.gov (United States)

    Cranny, A.; Cotton, D. P. J.; Chappell, P. H.; Beeby, S. P.; White, N. M.

    2005-04-01

    Thick-film static and dynamic force sensors have been investigated for their suitability to measure the grip forces exerted upon an object held by a prosthetic hand, and to detect and correspondingly react to the possible slip of a gripped item. The static force sensors exploit the piezoresistive characteristics of commercially available thick-film pastes whilst the dynamic slip sensors utilize the piezoelectric behaviour of proprietary PZT (lead zirconate titanate) pastes. The sensors are located upon stainless steel cantilever type structures that will be placed at the fingertips of each digit of the prosthetic hand. Temperature sensors are also included to provide temperature compensation for the force sensors and to prevent accidental thermal damage to the prosthesis. Results have shown that the static force sensor is capable of measuring fingertip forces in excess of 100 N, with an electrical half-bridge configuration sensitivity approaching 10 µV V-1 N-1 (with scope for improvement) and maximum hysteresis below 4% of full scale, depending on the manner in which the cantilever sensor array is attached to the finger. Failure in the bonding mechanism that secures the PZT layer to the stainless steel cantilever meant that the proposed dynamic force sensor could not be evaluated. However, investigations using the same sensor design fabricated on an alumina substrate have shown the potential of the PZT dynamic force sensor to measure the vibration and hence potentially operate as a slip sensor.

  9. Platinum and palladium doped tin oxide thick film sensors for sensing methane and hydrogen

    Science.gov (United States)

    Choudhary, Meenakshi; Mishra, V. N.; Dwivedi, R.

    2013-01-01

    In this work, platinum (Pt) and palladium (Pd) doped SnO2 thick film sensors have been developed using solid state derived tin oxide powder. Thick film sensors were fabricated on a 1˝x1˝ alumina substrate. The crystal structure and particle size are confirmed by X-ray diffraction (XRD) pattern. The fabricated sensors are tested for varying concentration (1-5%) of hydrogen and methane gas at different operating temperatures (200-350 °C). The effect of Pt and Pd doping have been analysed on different operating temperature, sensitivity and response/recovery time. The doping effects are also very important from view point of the gas selectivity. Based on the experimental results, we have observed the formation of tetragonal structure and particle size of the powders is drastically decreases from 26 to 19 nm after replacing the platinum dopant with palladium. Both the doped sensors have been found to be sensitive for hydrogen as compare to methane however, Pd-doped SnO2 sensor are most selective for hydrogen with very fast response and recovery time (20 s, 101 s) due to the small size effect.

  10. Anomalous thickness variation of the foam films stabilized by weak non-ionic surfactants.

    Science.gov (United States)

    Qu, Xuan; Wang, Liguang; Karakashev, Stoyan I; Nguyen, Anh V

    2009-09-15

    The constant thickness (H) of metastable free films of various non-ionic surfactant solutions was measured at surfactant concentrations less than the critical micelle concentrations or solubility limits with fixed 5x10(-5) M sodium chloride (NaCl) serving as the background electrolyte. The surfactants include n-pentanol, n-octanol, methyl isobutyl carbinol (MIBC), polypropylene glycol (PPG-400), tetraethylene glycol monooctyl ether (C(8)E(4)), and tetraethylene glycol monodecyl ether (C(10)E(4)). H was interferometrically measured. For each surfactant in this study, the H-versus-surfactant-concentration curve finds a peak at a concentration around 5x10(-6)-1x10(-5) M and a valley at a higher concentration. The measured H values were compared to those predicted from the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, which considers solely the contribution from electrostatic double-layer repulsion with van der Waals attraction being neglected in the present work. In determining the double-layer repulsion, the ionic strength was determined from the electrolytic conductivity measurement of the film-forming solutions and the surface potential was estimated from the zeta-potential measurement of air bubbles. It was found that the DLVO theory failed to explain the thickness variance with surfactant concentration, implying that additional non-DLVO attractive forces might be required to explain the experimental results. Finally, the possible origins of these attractive forces were discussed.

  11. Thickness dependence of dispersion parameters of the MoO{sub x} thin films prepared using the vacuum evaporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Akın, Ümmühan, E-mail: uakin@selcuk.edu.tr; Şafak, Haluk

    2015-10-25

    The optical behaviors of molybdenum oxide thin films are highly important due to their widespread applications. In the present paper, the effect of thickness on the structure, morphology and optical properties of molybdenum oxide (MoO{sub x}) thin films prepared on Corning glass substrates using thermal evaporation technique was studied. The structure and morphology of films were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively, while their optical properties were investigated by UV-VIS-NIR spectrophotometry in the spectral range from 300 to 2500 nm. It was observed that whole films have amorphous structure and also they showed rather high transmittance values reached nearly up to 90%. Absorption analysis showed two types of electronic transitions; both direct and indirect interband transition energy values of films decrease from 4.47 to 3.45 eV and from 3.00 to 2.75 eV, respectively, with increasing the film thickness, while the width of the localized states tail increases with thickness. This decrease in the band gap value can be attributed to the rising oxygen-ion vacancy densities with the thickness. The refractive indices of films were calculated from Sellmeier coefficients determined by nonlinear curve fitting method based on the measured transmittance spectral data. The dispersion of the refractive index was discussed in terms of the Wemple-DiDomenico single-oscillator model. The dispersion parameters such as average oscillator energy, E{sub o}, the dispersion energy, E{sub d}, and static refractive index n{sub o} were evaluated and they found to vary significantly with the film thickness. - Highlights: • MoO{sub x} thin films with different thickness were prepared using the vacuum evaporation technique. • The variation of fundamental absorption edge with the film thickness was determined. • A detailed dispersion analysis based on the Wemple-DiDomenico model was performed. • The dependence of all

  12. Fabrication and characterization of thick-film piezoelectric lead zirconate titanate ceramic resonators by tape-casting.

    Science.gov (United States)

    Qin, Lifeng; Sun, Yingying; Wang, Qing-Ming; Zhong, Youliang; Ou, Ming; Jiang, Zhishui; Tian, Wei

    2012-12-01

    In this paper, thick-film piezoelectric lead zirconate titanate (PZT) ceramic resonators with thicknesses down to tens of micrometers have been fabricated by tape-casting processing. PZT ceramic resonators with composition near the morphotropic phase boundary and with different dopants added were prepared for piezoelectric transducer applications. Material property characterization for these thick-film PZT resonators is essential for device design and applications. For the property characterization, a recently developed normalized electrical impedance spectrum method was used to determine the electromechanical coefficient and the complex piezoelectric, elastic, and dielectric coefficients from the electrical measurement of resonators using thick films. In this work, nine PZT thick-film resonators have been fabricated and characterized, and two different types of resonators, namely thickness longitudinal and transverse modes, were used for material property characterization. The results were compared with those determined by the IEEE standard method, and they agreed well. It was found that depending on the PZT formulation and dopants, the relative permittivities ε(T)(33)/ε(0) measured at 2 kHz for these thick-films are in the range of 1527 to 4829, piezoelectric stress constants (e(33) in the range of 15 to 26 C/m(2), piezoelectric strain constants (d(31)) in the range of -169 × 10(-12) C/N to -314 × 10(-12) C/N, electromechanical coupling coefficients (k(t)) in the range of 0.48 to 0.53, and k(31) in the range of 0.35 to 0.38. The characterization results shows tape-casting processing can be used to fabricate high-quality PZT thick-film resonators, and the extracted material constants can be used to for device design and application.

  13. 厚膜金导体浆料%Thick-Film Gold Conductor Pastes

    Institute of Scientific and Technical Information of China (English)

    李世鸿

    2001-01-01

    概括介绍了厚膜金导体浆料。通过改变金粉、粘结剂和有机载体等主要组份的类型和含量,可以制得多种金浆料。①粘结剂类型对厚膜金导体的性能有较大的影响。根据附着机理分类,厚膜金导体分为4种主要类型,即玻璃结合型、反应结合型、混合结合型和表面活化结合型。②金粉颗粒的均匀性、单分散性、表面形态及尺寸对浆料的印刷性能和烧结性能影响大。颗粒表面越光滑,对提高印刷性能越有利。光滑的表面吸附有机载体较少,可减少导体膜在烘干—烧结时的收缩率。③有机载体的含量和流变学性能影响金浆料的印刷性能及烘干—烧结时的收缩率。④金浆中添加起合金化作用的元素,可提高导体在铝丝键合体系及Pb-In焊接体系的热老化性能。⑤为适应新的厚膜工艺技术的需要,研制可光刻的厚膜金导体浆料和金的金属有机浆料[Au MOC]。%Thick-film gold conductor pastes are summarized in this paper.Many kinds of gold pastes are made by changing types and contents of main components such as gold powder,binder and organic vehicle.1.The types of binders deeply affect the characteristics of thick-film gold conductors.Depending on the adhesion mechanisms,thick-film gold conductors are classified into four main types:the fritted-bonded,the reactivity-bonded,the mixed-bonded and the surface activated-bonded systems.2.The homogeneity,monodisperesability,morphology and size of the gold powder particles greatly influence the paste printability and sintering properties.The smoother surface renders the pastes greater printability,and the lower vehicle absorption rate resulting from smooth surface can reduce shrinkage.3.The content and rheology of organic vehicle influence the paste printability and dried-fired shinkage.4.The addition of alloyed elements to gold pastes can improve the thermal-ageing performance in Al-wire bonding and

  14. Thickness-dependent retention behaviors and ferroelectric properties of BiFeO3 thin films on BaPbO3 electrodes

    Science.gov (United States)

    Lee, Chia-Ching; Wu, Jenn-Ming

    2007-09-01

    BiFeO3 (BFO) thin films produced with varied film thicknesses ranging from 100to230nm were fabricated on BaPbO3(BPO )/Pt/Ti/SiOx/Si substrates by rf-magnetron sputtering. Saturated polarization-electrical field hysteresis loops, polarization response by pulse measurement, and retention properties were obtained for BFO films with various thicknesses on BPO. The retention behaviors of BFO demonstrate logarithmic time dependence and stretched exponential law. When the thicknesses of BFO films increase, the contribution of logarithmic time dependence to retention, the stretched exponential law becomes dominant. BFO films with thinner thickness exhibit better retention properties but possess smaller remnant polarization.

  15. Quality estimation of thick-film resistor terminations based on electrical parameters extraction

    Science.gov (United States)

    Kiełbasiński, Konrad; Jakubowska, Małgorzata; Kalenik, Jerzy; Młożniak, Anna

    2008-01-01

    The RoHS and WEEE regulation forced the large investigations for environmental friendly materials in electronic. The Lead and cadmium which was the significant component of resistors and conductors used in thick-film technology have to be replaced. Quick and precise measurement techniques need to be elaborated to maintain consumer's demand. Usually the test samples with the conductive and resistive layers were used for electrical parameters measurements. The layer thickness measurements and mean value of resistance allowed calculating the sheet resistance. Such a method of measurement have very serious disadvantage. The calculated mean value can be significantly affected by resistors terminations, especially if silver conductor is used, which is known as an easily migrating material. The solution was known and involved preparing and printing samples with the reference terminations. Silver platinum and silver palladium conductors are less susceptible to migration, therefore they were used in previous investigations. The reference terminations improves the precision of calculating sheet resistance, however they enlarges the number of measurements and its influence could still be significant. The authors proposed completely new method of sheet resistance calculation. Such a calculated value called True Sheet Resistance do not depend on the phenomena taking place at the termination, The second evaluated value called Offset indicates the influence of the terminations on measured resistance, and also termination quality. Its value is correlated with the diffusion rate at the interface between conductive film and resistive film at the termination. The usability of this method was proven by performing multiple firing test. One kind of resistive layer was printed on different kinds of conductive layers. The samples were fired sequently and measured. Then the old method of resistor properties evaluation was compared to the new one.

  16. Structural and magnetic properties of Co−Ti substituted barium hexaferrite thick films

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Samiksha; Pandey, O.P. [School of Physics and Materials Science, Thapar University Patiala, 147004, Punjab (India); Paesano, Andrea [Departamento de Física, Universidade Estadual de Maringá, Av. Colombo, 5790, Maringá (Brazil); Sharma, Puneet, E-mail: puneet.sharma@thapar.edu [School of Physics and Materials Science, Thapar University Patiala, 147004, Punjab (India)

    2016-09-05

    Co−Ti substituted M-type barium hexaferrite BaFe{sub 12-2x}Co{sub x}Ti{sub x}O{sub 19} (0.0 ≤ x ≤ 1.0) thick films were prepared by screen printing method. X-ray diffraction analysis confirmed the formation of single phase BaFe{sub 12}O{sub 19} (BaM). The preferential site occupation of Co{sup 2+} and Ti{sup 4+} ion for Fe{sup 3+} ion at five different crystallographic sites (12k, 4f{sub 1}, 4f{sub 2}, 2a, and 2b) was measured by Mössbauer spectroscopy. The analyses showed Co−Ti ions preferentially occupy 2b and 4f{sub 2} sites which were responsible for drastic decrease in magnetocrystalline anisotropy field (H{sub a}). Magnetization (M) value found to be higher for x = 0.5. The coercivity (H{sub c}) dropped dramatically, recording a reduction of about 95% at x = 1.0, attributed to decreased in H{sub a}. SEM micrographs of Co−Ti substituted films revealed hexagonal grain structure. The magnetic properties of Co−Ti substituted BaM, suggests a possible candidate for microwave applications. - Highlights: • Single phase Co−Ti substituted BaM thick films are prepared from screen printing method. • The effect of Co−Ti substitution on structural and magnetic properties is studied. • Mössbauer spectroscopy illustrate, Co−Ti ions are preferentially occupy 2b and 4f{sub 2} sites. • Drastic decrease in magnetocrystalline anisotropy (H{sub a}) and (H{sub c}) is observed.

  17. Structural, morphological, optical and electrical properties of NiO films prepared on Si (100) and glass substrates at different thicknesses

    Science.gov (United States)

    Ahmed, Anas A.; Afzal, Naveed; Devarajan, Mutharasu; Subramani, Shanmugan

    2016-11-01

    In this work, structural, surface, optical and electrical properties of NiO films were studied at different film thicknesses. The NiO films of different thicknesses in the range 330-920 nm were prepared on Si (100) and glass substrates by using radiofrequency magnetron sputtering of NiO target at 100 °C. The structural study through XRD indicated polycrystalline NiO films with preferred orientation along (200) plane. The crystalline quality of the films was improved with increase of the film thickness on both substrates, however, the films prepared on Si (100) displayed better crystallinity as compared to the films prepared on the glass. The morphological features of the film as studied through FE-SEM displayed an increase of grain size with increase of its thickness, however, the grain size of the film on Si (100) was found to be slightly larger than that of the glass. The band gap of NiO film was decreased with increase of the film thickness on both the substrates. The films grown on Si (100) exhibited superior electrical properties as compared to the films prepared on glass at all film thicknesses.

  18. The Effect of Deposition Time on Textured Magnesium Diboride Thick Films Fabricated by Electrophoretic Deposition

    Directory of Open Access Journals (Sweden)

    W. G. Mutia

    2004-12-01

    Full Text Available MgB2 powders suspended in ethanol were electrophoretically deposited on high-purity molybdenum substrates having dimensions of 1 x 0.3 x 0.01 cm. The said substrate was set as the cathode and was placed 0.5 cm away from a graphite rod anode. A current density of ~0.02 mA/cm2 and a voltage of 600 V were applied. The effect of deposition time was studied by varying it as follows: 15 s, 30 s, 1 min, and 2 min. Heat treatment at 950 oC for 3 h was done after deposition. MgB2 thick films were successfully fabricated for the deposition carried out for 2 min. Deposition times less than 2 min resulted in insufficient deposited powder; hence formation of MgB2 was not facilitated. Films deposited at 15 and 30 s have good surface characteristics, wherein no microcracks were present. X-ray diffraction and surface image analysis reveal that the deposited films have a preferred orientation along the (10l direction.

  19. Synthesis and Characterization of Vanadium Doped Zinc Oxide Thick Film for Chemical Sensor Application

    Directory of Open Access Journals (Sweden)

    Rayees Ahmad Zargar

    2015-01-01

    Full Text Available Zinc oxide and vanadium pentoxide nanoparticles derived by chemical coprecipitation route were used to cast Zn0.96V0.04O thick film by screen printing method. The structural, morphological, optical, and electrical properties of the film were characterized by powder XRD, SEM, Raman, UV-VIS, and DC conductivity techniques. XRD pattern, SEM image, and Raman spectrum of the film confirm the single phase formation of Wurtzite structure with preferential orientation along [101] plane, minor variation in lattice parameters, and vanadium ions substitution at zinc sites. Zn0.96V0.04O pellet has been used for sensing ammonia vapor concentrations in 20–50°C temperature range which exhibits maximum responsiveness and sensitivity at 30°C. The minor variations in resistance are observed with ammonia vapor concentration. The adsorption of ammonia vapors through weak hydrogen bonding and its insertion into lattice by nitrogen lone pairs donation at vacant/defect sites in lattice caused by vanadium doping are considered to explain gas sensing mechanism.

  20. Transport study of Ba-deficient thin-film Y123 superconductors enriched with Na

    Energy Technology Data Exchange (ETDEWEB)

    Pekala, M.; Bougrine, H.; Azoulay, J.; Ausloos, M. [Dept. of Chem., Warsaw Univ. (Poland)

    1995-08-01

    Nominal Y{sub 0.3}Ba{sub 0.6}Na{sub 0.1}CuO{sub 3-{delta}} thin films were prepared with small grains having an orientation of the c axis perpendicular to the MgO substrate. The electrical resistivity and the thermoelectric power in the absence and in the presence of a magnetic field are reported. The magnetic field dependence of the irreversibility line is discussed. The role of the field for disentangling intragrain and intergrain effects in both coefficients is emphasized. (author)