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Sample records for thin-film multijunction thermal

  1. A New Fabrication Process for Thin-Film Multijunction Thermal Converters

    Energy Technology Data Exchange (ETDEWEB)

    WUNSCH,THOMAS F.; KINARD,J.R.; MANGINELL,RONALD P.; SOLOMON JR.,OTIS M.; LIPE,T.E.; JUNGLING,KENNETH CORNEAL

    2000-12-08

    Advanced thin film processing and packaging technologies are employed in the fabrication of new planar thin-film multifunction thermal converters. The processing, packaging, and design features build on experience gained from prior NIST demonstrations of thin-film converters and are optimized for improved sensitivity, bandwidth, manufacturability, and reliability.

  2. Thermal conductivity of dielectric thin films

    International Nuclear Information System (INIS)

    Lambropoulos, J.C.; Jolly, M.R.; Amaden, C.A.; Gilman, S.E.; Sinicropi, M.J.; Diakomihalis, D.; Jacobs, S.D.

    1989-05-01

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

  3. Thermal conductivity model for nanoporous thin films

    Science.gov (United States)

    Huang, Congliang; Zhao, Xinpeng; Regner, Keith; Yang, Ronggui

    2018-03-01

    Nanoporous thin films have attracted great interest because of their extremely low thermal conductivity and potential applications in thin thermal insulators and thermoelectrics. Although there are some numerical and experimental studies about the thermal conductivity of nanoporous thin films, a simplified model is still needed to provide a straightforward prediction. In this paper, by including the phonon scattering lifetimes due to film thickness boundary scattering, nanopore scattering and the frequency-dependent intrinsic phonon-phonon scattering, a fitting-parameter-free model based on the kinetic theory of phonon transport is developed to predict both the in-plane and the cross-plane thermal conductivities of nanoporous thin films. With input parameters such as the lattice constants, thermal conductivity, and the group velocity of acoustic phonons of bulk silicon, our model shows a good agreement with available experimental and numerical results of nanoporous silicon thin films. It illustrates that the size effect of film thickness boundary scattering not only depends on the film thickness but also on the size of nanopores, and a larger nanopore leads to a stronger size effect of the film thickness. Our model also reveals that there are different optimal structures for getting the lowest in-plane and cross-plane thermal conductivities.

  4. On-Orbit Demonstration of a Lithium-Ion Capacitor and Thin-Film Multijunction Solar Cells

    Science.gov (United States)

    Kukita, Akio; Takahashi, Masato; Shimazaki, Kazunori; Kobayashi, Yuki; Sakai, Tomohiko; Toyota, Hiroyuki; Takahashi, Yu; Murashima, Mio; Uno, Masatoshi; Imaizumi, Mitsuru

    2014-08-01

    This paper describes an on-orbit demonstration of the Next-generation Small Satellite Instrument for Electric power systems (NESSIE) on which an aluminum- laminated lithium-ion capacitor (LIC) and a lightweight solar panel called KKM-PNL, which has space solar sheets using thin-film multijunction solar cells, were installed. The flight data examined in this paper covers a period of 143 days from launch. We verified the integrity of an LIC constructed using a simple and lightweight mounting method: no significant capacitance reduction was observed. We also confirmed that inverted metamorphic multijunction triple-junction thin-film solar cells used for evaluation were healthy at 143 days after launch, because their degradation almost matched the degradation predictions for dual-junction thin-film solar cells.

  5. Thermal properties of methyltrimethoxysilane aerogel thin films

    Directory of Open Access Journals (Sweden)

    Leandro N. Acquaroli

    2016-10-01

    Full Text Available Aerogels are light and porous solids whose properties, largely determined by their nanostructure, are useful in a wide range of applications, e.g., thermal insulation. In this work, as-deposited and thermally treated air-filled silica aerogel thin films synthesized using the sol-gel method were studied for their thermal properties using the 3-omega technique, at ambient conditions. The thermal conductivity and diffusivity were found to increase as the porosity of the aerogel decreased. Thermally treated films show a clear reduction in thermal conductivity compared with that of as-deposited films, likely due to an increase of porosity. The smallest thermal conductivity and diffusivity found for our aerogels were 0.019 W m−1 K−1 and 9.8 × 10-9 m2 s−1. A model was used to identify the components (solid, gaseous and radiative of the total thermal conductivity of the aerogel.

  6. Thermal properties and stabilities of polymer thin films

    International Nuclear Information System (INIS)

    Kanaya, Toshiji; Kawashima, Kazuko; Inoue, Rintaro; Miyazaki, Tsukasa

    2009-01-01

    Recent extensive studies have revealed that polymer thin films showed very interesting but unusual thermal properties and stabilities. In the article we show that X-ray reflectivity and neutron reflectivity are very powerful tools to study the anomalous properties of polymer thin films. (author)

  7. Thermally stable antireflective coatings based on nanoporous organosilicate thin films.

    Science.gov (United States)

    Kim, Suhan; Cho, Jinhan; Char, Kookheon

    2007-06-05

    Thermally stable nanoporous organosilicate thin films were realized by the microphase separation of pore-generating polymers mixed with an organosilicate matrix to be antireflective coatings (ARCs), for which a thin film with a refractive index (n) of 1.23 for zero reflection is required. The refractive index of such nanoporous organosilicate films can be tuned from 1.39 down to 1.23 by incorporating nanopores within the films. With a nanoporous single layer with n approximately 1.23, the light transmittance of the glass above 99.8% was achieved in the visible range (lambda approximately 550 nm). To overcome the limitation on the narrow wavelength for high transmittance imposed by a single antireflective nanoporous thin film, bilayer thin films with different refractive indices were prepared by placing a high refractive index layer with a refractive index of 1.45 below the nanoporous thin film. UV-vis transmittance of a glass coated with the bilayer films was compared with nanoporous single-layer films and it is demonstrated that the novel broadband antireflection coatings in a wide range of visible wavelength can be easily obtained by the organosilicate bilayer thin films described in this study. Also, ARCs developed in this study demonstrate excellent AR durability owing to the hydrophobic nature of the organosilicate matrix.

  8. Glass transition and thermal expansivity of polystyrene thin films

    International Nuclear Information System (INIS)

    Inoue, R.; Kanaya, T.; Miyazaki, T.; Nishida, K.; Tsukushi, I.; Shibata, K.

    2006-01-01

    We have studied glass transition temperature and thermal expansivity of polystyrene thin films supported on silicon substrate using X-ray reflectivity and inelastic neutron scattering techniques. In annealing experiments, we have found that the reported apparent negative expansivity of polymer thin films is caused by unrelaxed structure due to insufficient annealing. Using well-annealed films, we have evaluated glass transition temperature T g and thermal expansivity as a function of film thickness. The glass transition temperature decreases with film thickness and is constant below about 10 nm, suggesting the surface glass transition temperature of 355 K, which is lower than that in bulk. We have also found that the thermal expansivity in the glassy state decreases with film thickness even after annealing. The decrease has been attributed to hardening of harmonic force constant arising from chain confinement in a thin film. This idea has been confirmed in the inelastic neutron scattering measurements

  9. Glass transition and thermal expansivity of polystyrene thin films

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, R. [Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011 (Japan); Kanaya, T. [Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011 (Japan)]. E-mail: kanaya@scl.kyoto-u.ac.jp; Miyazaki, T. [Nitto Denko Corporation, 1-1-2 Shimohozumi, Ibaraki, Osaka-fu 567-8680 (Japan); Nishida, K. [Institute for Chemical Research, Kyoto University, Uji, Kyoto-fu 611-0011 (Japan); Tsukushi, I. [Chiba Institute of Technology, Narashino, Chiba-ken 275-0023 (Japan); Shibata, K. [Japan Atomic Energy Research Institute, Tokai, Ibaraki-ken 319-1195 (Japan)

    2006-12-20

    We have studied glass transition temperature and thermal expansivity of polystyrene thin films supported on silicon substrate using X-ray reflectivity and inelastic neutron scattering techniques. In annealing experiments, we have found that the reported apparent negative expansivity of polymer thin films is caused by unrelaxed structure due to insufficient annealing. Using well-annealed films, we have evaluated glass transition temperature T {sub g} and thermal expansivity as a function of film thickness. The glass transition temperature decreases with film thickness and is constant below about 10 nm, suggesting the surface glass transition temperature of 355 K, which is lower than that in bulk. We have also found that the thermal expansivity in the glassy state decreases with film thickness even after annealing. The decrease has been attributed to hardening of harmonic force constant arising from chain confinement in a thin film. This idea has been confirmed in the inelastic neutron scattering measurements.

  10. Mobility activation in thermally deposited CdSe thin films

    Indian Academy of Sciences (India)

    Effect of illumination on mobility has been studied from the photocurrent decay characteristics of thermally evaporated CdSe thin films deposited on suitably cleaned glass substrate held at elevated substrate temperatures. The study indicates that the mobilities of the carriers of different trap levels are activated due to the ...

  11. Low thermal emissivity surfaces using AgNW thin films

    Science.gov (United States)

    Pantoja, Elisa; Bhatt, Rajendra; Liu, Anping; Gupta, Mool C.

    2017-12-01

    The properties of silver nanowire (AgNW) films in the optical and infrared spectral regime offer an interesting opportunity for a broad range of applications that require low-emissivity coatings. This work reports a method to reduce the thermal emissivity of substrates by the formation of low-emissivity AgNW coating films from solution. The spectral emissivity was characterized by thermal imaging with an FLIR camera, followed by Fourier transform infrared spectroscopy. In a combined experimental and simulation study, we provide fundamental data of the transmittance, reflectance, haze, and emissivity of AgNW thin films. Emissivity values were finely tuned by modifying the concentration of the metal nanowires in the films. The simulation models based on the transfer matrix method developed for the AgNW thin films provided optical values that show a good agreement with the measurements.

  12. Thermal Conductivity in Nanocrystalline Ceria Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Marat Khafizov; In-Wook Park; Aleksandr Chernatynskiy; Lingfeng He; Jianliang Lin; John J. Moore; David Swank; Thomas Lillo; Simon R. Phillpot; Anter El-Azab; David H. Hurley

    2014-02-01

    The thermal conductivity of nanocrystalline ceria films grown by unbalanced magnetron sputtering is determined as a function of temperature using laser-based modulated thermoreflectance. The films exhibit significantly reduced conductivity compared with stoichiometric bulk CeO2. A variety of microstructure imaging techniques including X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron analysis, and electron energy loss spectroscopy indicate that the thermal conductivity is influenced by grain boundaries, dislocations, and oxygen vacancies. The temperature dependence of the thermal conductivity is analyzed using an analytical solution of the Boltzmann transport equation. The conclusion of this study is that oxygen vacancies pose a smaller impediment to thermal transport when they segregate along grain boundaries.

  13. Heat Transfer Issues in Thin-Film Thermal Radiation Detectors

    Science.gov (United States)

    Barry, Mamadou Y.

    1999-01-01

    The Thermal Radiation Group at Virginia Polytechnic Institute and State University has been working closely with scientists and engineers at NASA's Langley Research Center to develop accurate analytical and numerical models suitable for designing next generation thin-film thermal radiation detectors for earth radiation budget measurement applications. The current study provides an analytical model of the notional thermal radiation detector that takes into account thermal transport phenomena, such as the contact resistance between the layers of the detector, and is suitable for use in parameter estimation. It was found that the responsivity of the detector can increase significantly due to the presence of contact resistance between the layers of the detector. Also presented is the effect of doping the thermal impedance layer of the detector with conducting particles in order to electrically link the two junctions of the detector. It was found that the responsivity and the time response of the doped detector decrease significantly in this case. The corresponding decrease of the electrical resistance of the doped thermal impedance layer is not sufficient to significantly improve the electrical performance of the detector. Finally, the "roughness effect" is shown to be unable to explain the decrease in the thermal conductivity often reported for thin-film layers.

  14. Structure and Thermal Stability of Copper Nitride Thin Films

    Directory of Open Access Journals (Sweden)

    Guangan Zhang

    2013-01-01

    Full Text Available Copper nitride (Cu3N thin films were deposited on glass via DC reactive magnetron sputtering at various N2 flow rates and partial pressures with 150°C substrate temperature. X-ray diffraction and scanning electron microscopy were used to characterize the microstructure and morphology. The results show that the films are composed of Cu3N crystallites with anti-ReO3 structure. The microstructure and morphology of the Cu3N film strongly depend on the N2 flow rate and partial pressure. The cross-sectional micrograph of the film shows typical columnar, compact structure. The thermal stabilities of the films were investigated using vacuum annealing under different temperature. The results show that the introducing of argon in the sputtering process decreases the thermal stability of the films.

  15. Scanning thermal probe microscope method for the determination of thermal diffusivity of nanocomposite thin films

    Science.gov (United States)

    Varandani, Deepak; Agarwal, Khushboo; Brugger, Juergen; Mehta, Bodh Raj

    2016-08-01

    A commercial scanning thermal microscope has been upgraded to facilitate its use in estimating the radial thermal diffusivity of thin films close to room temperature. The modified setup includes a microcontroller driven microhotplate coupled with a Bluetooth module for wireless control. The microcontroller board (Arduino Leonardo) is used to generate a bias of suitable voltage amplitude and pulse duration which is applied across the microhotplate contact pads. A corresponding heat pulse from the Pt heating element (1 mm2) embedded within the microhotplate is delivered to the lower surface of the thin film (25 mm2) deposited over it. The large difference in the dimensions of the heating source and the thin film surface causes heat to flow radially outwards on the top surface of the latter. The decay of this radial heat wave as it flows outwards is recorded by the scanning thermal microscope in terms of temperature-time (T-t) profiles at varying positions around the central heating zone. A fitting procedure is suggested to extract the thermal diffusivity value from the array of T-t profiles. The efficacy of the above setup has been established by evaluating the thermal diffusivities of Bi2Te3 and Bi2Te3:Si thin film samples. Further, with only minor alterations in design the capabilities of the above setup can be extended to estimate the axial thermal diffusivity and specific heat of thin films, as a function of temperature.

  16. Thermal stability of gold-PS nanocomposites thin films

    Indian Academy of Sciences (India)

    Low-temperature transmission electron microscopy (TEM) studies were performed on polystyrene (PS, w = 234 K) – Au nanoparticle composite thin films that were annealed up to 350°C under reduced pressure conditions. The composite thin films were prepared by wet chemical approach and the samples were then ...

  17. Thermal and structural properties of spray pyrolysed CdS thin film

    Indian Academy of Sciences (India)

    Unknown

    Thermal and structural properties of CdS thin film. 235. 235 by photoacoustic technique. Polycrystalline CdTe films having 55 µm thickness were grown onto the glass slides using the close space vapour technique. The total thick- ness of two-layer system (glass and CdSe thin film) could be changed by varying the thickness ...

  18. Thermal stability of pulsed laser deposited iridium oxide thin films at low oxygen atmosphere

    Science.gov (United States)

    Gong, Yansheng; Wang, Chuanbin; Shen, Qiang; Zhang, Lianmeng

    2013-11-01

    Iridium oxide (IrO2) thin films have been regarded as a leading candidate for bottom electrode and diffusion barrier of ferroelectric capacitors, some process related issues need to be considered before integrating ferroelectric capacitors into memory cells. This paper presents the thermal stability of pulsed laser deposited IrO2 thin films at low oxygen atmosphere. Emphasis was given on the effect of post-deposition annealing temperature at different oxygen pressure (PO2) on the crystal structure, surface morphology, electrical resistivity, carrier concentration and mobility of IrO2 thin films. The results showed that the thermal stability of IrO2 thin films was strongly dependent on the oxygen pressure and annealing temperature. IrO2 thin films can stably exist below 923 K at PO2 = 1 Pa, which had a higher stability than the previous reported results. The surface morphology of IrO2 thin films depended on PO2 and annealing temperature, showing a flat and uniform surface for the annealed films. Electrical properties were found to be sensitive to both the annealing temperature and oxygen pressure. The room-temperature resistivity of IrO2 thin films with a value of 49-58 μΩ cm increased with annealing temperature at PO2 = 1 Pa. The thermal stability of IrO2 thin films as a function of oxygen pressure and annealing temperature was almost consistent with thermodynamic calculation.

  19. Thermally stimulated nonlinear refraction in gelatin stabilized Cu-PVP nanocomposite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tamgadge, Y. S., E-mail: ystamgadge@gmail.com; Atkare, D. V. [Department of Physics, Mahatma Fule Arts, Commerce & SitaramjiChoudhari Science College, Warud, Dist. Amravati (MS), India-444906 (India); Pahurkar, V. G.; Muley, G. G., E-mail: gajananggm@yahoo.co.in [Department of Physics, SantGadge Baba Amravati University, Amravati (MS), India-444602 (India); Talwatkar, S. S. [Department of Physics, D K Marathe and N G Acharya College, Chembur, Mumbai (MS), India-440071 (India); Sunatkari, A. L. [Department of Physics, Siddharth College of Arts, Science and Commerce, Fort, Mumbai (MS), India-440001 (India)

    2016-05-06

    This article illustrates investigations on thermally stimulated third order nonlinear refraction of Cu-PVP nanocomposite thin films. Cu nanoparticles have been synthesized using chemical reduction method and thin films in PVP matrix have been obtained using spin coating technique. Thin films have been characterized by X-ray diffraction (XRD) and Ultraviolet-visible (UV-vis) spectroscopyfor structural and linear optical studies. Third order nonlinear refraction studies have been performed using closed aperture z-scan technique under continuous wave (CW) He-Ne laser. Cu-PVP nanocomposites are found to exhibit strong nonlinear refractive index stimulated by thermal lensing effect.

  20. Impact of embedded voids on thin-films with high thermal expansion coefficients mismatch

    Science.gov (United States)

    Khafagy, Khaled H.; Hatem, Tarek M.; Bedair, Salah M.

    2018-01-01

    Using technology to reduce defects at heterogeneous interfaces of thin-films is at a high-priority for modern semiconductors. The current work utilizes a three-dimensional multiple-slip crystal-plasticity model and specialized finite-element formulations to study the impact of the embedded void approach (EVA) to reduce defects in thin-films deposited on a substrate with a highly mismatched thermal expansion coefficient, in particular, the growth of an InGaN thin-film on a Si substrate, where EVA has shown a remarkable reduction in stresses on the side of the embedded voids.

  1. Wide-bandgap CIAS thin-film photovoltaics with transparent back contacts for next generation single and multi-junction devices

    International Nuclear Information System (INIS)

    Woods, Lawrence M.; Kalla, Ajay; Gonzalez, Damian; Ribelin, Rosine

    2005-01-01

    This paper discusses the performance, testing, and problems of copper indium aluminum diselenide (CIAS) thin-film devices with CIAS co-evaporated in a large-area moving substrate deposition system on transparent back contact technology. The CIAS alloy is being developed for use as a wide-bandgap radiation-resistant semiconductor for application as both a high-voltage single-junction photovoltaic (PV) cell using low-cost thin-films on lightweight flexible substrates, and as a top cell in efficient two-terminal monolithic tandem (multi-junction) PV cells. After significant development, it appears that conventionally formed CIAS devices experience a drop-off in performance with CIAS bandgaps above 1.5 eV, in addition to decreased zero bias depletion widths, and increased J L (V) effects with increasing CIAS bandgap. However, the performance drop-off is above the single-junction optimum bandgap, and higher-bandgap devices have not been tested with better-matched buffer layers. This paper also discusses CIAS devices with transparent back contacts. A wide-bandgap CIAS device with infra-red (IR) transparent back contacts and substrates can offer better performance over standard CIGS devices by being better tuned to the optimum bandgap for AM0 solar spectrum, reduced ohmic losses, and temperature dependencies compared to that typical of low-bandgap CIS alloys, reduced operating temperature with better IR transparency, the option of backside light collection with a suitable visibly transparent substrate, and is a precursor for use as a top cell in a monolithic tandem device configuration. CIAS devices with transparent back contacts show no loss in performance compared to standard Mo back contacts

  2. Gas Control and Thermal Modeling Methods for Pressed Pellet and Fast Rise Thin-Film Thermal Batteries

    Science.gov (United States)

    2015-09-01

    E PIEKOS 2 ADVANCED THERMAL (PDF) BATTERIES , INC D BRISCOE G CHAGNON 3 EAGLE PICHER (PDF) TECHNOLOGIES, LLC C LAMB J...Thin-Film Thermal Batteries by Frank C Krieger and Michael S Ding Approved for public release; distribution unlimited...Laboratory Gas Control and Thermal Modeling Methods for Pressed Pellet and Fast Rise Thin-Film Thermal Batteries by Frank C Krieger and Michael S

  3. Mobility activation in thermally deposited CdSe thin films

    Indian Academy of Sciences (India)

    Administrator

    3. Mobility activation in CdSe thin films. The trap depths were calculated by using the following simple decay law. It = Ioexp(–pt),. (1) where p is the probability of escape of an electron from the trap per second and is given by (Randall and Wilkins 1945) p = S exp (–E/kT),. (2) where E is the trap depth for electrons below the ...

  4. The thickness of DLC thin film affects the thermal conduction of HPLED lights

    Science.gov (United States)

    Hsu, Ming Seng; Huang, Jen Wei; Shyu, Feng Lin

    2016-09-01

    Thermal dissipation had an important influence in the quantum effect and life of light emitting diodes (LED) because it enabled heat transfer away from electric devices to the aluminum plate for heat removal. In the industrial processing, the quality of the thermal dissipation was decided by the gumming technique between the PCB and aluminum plate. In this study, we made the ceramic thin films of diamond like carbon (DLC) by vacuum sputtering between the substrate and high power light emitting diodes (HPLED) light to check the influence of heat transfer by DLC thin films. The ceramic dielectric coatings were characterized by several subsequent analyses, especially the measurement of real work temperature of HPLEDs. The X-Ray photoelectron spectroscopy (XPS) patterns revealed that ceramic phases were successfully grown onto the substrate. At the same time, the real work temperatures showed the thickness of DLC thin film coating effectively affected the thermal conduction of HPLEDs.

  5. Fabrication of thermally evaporated Al thin film on cylindrical PET monofilament for wearable computing devices

    Science.gov (United States)

    Liu, Yang; Kim, Eunju; Han, Jeong In

    2016-01-01

    During the initial development of wearable computing devices, the conductive fibers of Al thin film on cylindrical PET monofilament were fabricated by thermal evaporation. Their electrical current-voltage characteristics curves were excellent for incorporation into wearable devices such as fiber-based cylindrical capacitors or thin film transistors. Their surfaces were modified by UV exposure and dip coating of acryl or PVP to investigate the surface effect. The conductive fiber with PVP coating showed the best conductivities because the rough surface of the PET substrate transformed into a smooth surface. The conductivities of PET fiber with and without PVP were 6.81 × 103 Ω-1cm-1 and 5.62 × 103 Ω-1cm-1, respectively. In order to understand the deposition process of Al thin film on cylindrical PET, Al thin film on PET fiber was studied using SEM (Scanning Electron Microscope), conductivities and thickness measurements. Hillocks on the surface of conductive PET fibers were observed and investigated by AFM on the surface. Hillocks were formed and grown during Al thermal evaporation because of severe compressive strain and plastic deformation induced by large differences in thermal expansion between PET substrate and Al thin film. From the analysis of hillock size distribution, it turns out that hillocks grew not transversely but longitudinally. [Figure not available: see fulltext.

  6. Development of a micro-thermal flow sensor with thin-film thermocouples

    Science.gov (United States)

    Kim, Tae Hoon; Kim, Sung Jin

    2006-11-01

    A micro-thermal flow sensor is developed using thin-film thermocouples as temperature sensors. A micro-thermal flow sensor consists of a heater and thin-film thermocouples which are deposited on a quartz wafer using stainless steel masks. Thin-film thermocouples are made of standard K-type thermocouple materials. The mass flow rate is measured by detecting the temperature difference of the thin-film thermocouples located in the upstream and downstream sections relative to a heater. The performance of the micro-thermal flow sensor is experimentally evaluated. In addition, a numerical model is presented and verified by experimental results. The effects of mass flow rate, input power, and position of temperature sensors on the performance of the micro-thermal flow sensor are experimentally investigated. At low values, the mass flow rate varies linearly with the temperature difference. The linearity of the micro-thermal flow sensor is shown to be independent of the input power. Finally, the position of the temperature sensors is shown to affect both the sensitivity and the linearity of the micro-thermal flow sensor.

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

    Science.gov (United States)

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

    2016-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Dhimmar, J. M., E-mail: bharatpmodi@gmail.com; Desai, H. N.; Modi, B. P. [Department of Physics, Veer Narmad South Gujarat University, Surat, Gujarat (India)

    2016-05-23

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

  9. 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.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  11. Efficient extraction of thin-film thermal parameters from numerical models via parametric model order reduction

    NARCIS (Netherlands)

    Bechtold, T.; Hohlfeld, D.; Rudnyi, E.B.; Günther, M.

    2010-01-01

    In this paper we present a novel highly efficient approach to determine material properties from measurement results. We apply our method to thermal properties of thin-film multilayers with three different materials, amorphous silicon, silicon nitride and silicon oxide. The individual material

  12. Modifying the thermal conductivity of small molecule organic semiconductor thin films with metal nanoparticles.

    Science.gov (United States)

    Wang, Xinyu; Parrish, Kevin D; Malen, Jonathan A; Chan, Paddy K L

    2015-11-04

    Thermal properties of organic semiconductors play a significant role in the performance and lifetime of organic electronic devices, especially for scaled-up large area applications. Here we employ silver nanoparticles (Ag NPs) to modify the thermal conductivity of the small molecule organic semiconductor, dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT). The differential 3-ω method was used to measure the thermal conductivity of Ag-DNTT hybrid thin films. We find that the thermal conductivity of pure DNTT thin films do not vary with the deposition temperature over a range spanning 24 °C to 80 °C. The thermal conductivity of the Ag-DNTT hybrid thin film initially decreases and then increases when the Ag volume fraction increases from 0% to 32%. By applying the effective medium approximation to fit the experimental results of thermal conductivity, the extracted thermal boundary resistance of the Ag-DNTT interface is 1.14 ± 0.98 × 10(-7) m(2)-K/W. Finite element simulations of thermal conductivity for realistic film morphologies show good agreement with experimental results and effective medium approximations.

  13. Thermal Stability of Copper-Aluminum Alloy Thin Films for Barrierless Copper Metallization on Silicon Substrate

    Science.gov (United States)

    Wang, C. P.; Dai, T.; Lu, Y.; Shi, Z.; Ruan, J. J.; Guo, Y. H.; Liu, X. J.

    2017-08-01

    Copper thin films with thickness of about 500 nm doped with different aluminum concentrations have been prepared by magnetron sputtering on Si substrate and their crystal structure, microstructure, and electrical resistivity after annealing at various temperatures (200°C to 600°C) for 1 h or at 400°C for different durations (1 h to 11 h) investigated by grazing-incidence x-ray diffraction (GIXRD) analysis, scanning electron microscopy (SEM), and four-point probe (FPP) measurements. Cu-1.8Al alloy thin film exhibited good thermal stability and low electrical resistivity (˜5.0 μΩ cm) after annealing at 500°C for 1 h or 400°C for 7 h. No copper silicide was observed at the Cu-Al/Si interface by GIXRD analysis or SEM for this sample. This result indicates that doping Cu thin film with small amounts of Al can achieve high thermal stability and low electrical resistivity, suggesting that Cu-1.8Al alloy thin film could be used for barrierless Cu metallization on Si substrate.

  14. Growth and structure of thermally evaporated Bi{sub 2}Te{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rogacheva, E.I., E-mail: rogacheva@kpi.kharkov.ua [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine); Budnik, A.V. [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine); Dobrotvorskaya, M.V.; Fedorov, A.G.; Krivonogov, S.I.; Mateychenko, P.V. [Institute for Single Crystals of NAS of Ukraine, 60 Lenin Prospect, Kharkov 61001 (Ukraine); Nashchekina, O.N.; Sipatov, A.Yu. [National Technical University “Kharkov Polytechnic Institute”, 21 Frunze St., Kharkov 61002 (Ukraine)

    2016-08-01

    The growth mechanism, microstructure, and crystal structure of the polycrystalline n-Bi{sub 2}Te{sub 3} thin films with thicknesses d = 15–350 nm, prepared by thermal evaporation in vacuum onto glass substrates, were studied. Bismuth telluride with Te excess was used as the initial material for the thin film preparation. The thin film characterization was performed using X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, scan electron microscopy, and electron force microscopy. It was established that the chemical composition of the prepared films corresponded rather well to the starting material composition and the films did not contain any phases apart from Bi{sub 2}Te{sub 3}. It was shown that the grain size and the film roughness increased with increasing film thickness. The preferential growth direction changed from [00l] to [015] under increasing d. The X-ray photoelectron spectroscopy studies showed that the thickness of the oxidized surface layer did not exceed 1.5–2.0 nm and practically did not change in the process of aging at room temperature, which is in agreement with the results reported earlier for single crystals. The obtained data show that using simple and inexpensive method of thermal evaporation in vacuum and appropriate technological parameters, one can grow n-Bi{sub 2}Te{sub 3} thin films of a sufficiently high quality. - Highlights: • The polycrystalline n-Bi{sub 2}Te{sub 3} thin films were grown thermal evaporation onto glass. • The growth mechanism and film structure were studied by different structure methods. • The grain size and film roughness increased with increasing film thickness. • The growth direction changes from [00l] to [015] under film thickness increasing. • The oxidized layer thickness (1–2 nm) did not change under aging at room temperature.

  15. Linear Coefficient of Thermal Expansion of Porous Anodic Alumina Thin Films from Atomic Force Microscopy

    OpenAIRE

    Zhang, Richard X; Fisher, Timothy; Raman, Arvind; Sands, Timothy D

    2009-01-01

    In this article, a precise and convenient technique based on the atomic force microscope (AFM) is developed to measure the linear coefficient of thermal expansion of a porous anodic alumina thin film. A stage was used to heat the sample from room temperature up to 450 K. Thermal effects on AFM probes and different operation modes at elevated temperatures were also studied, and a silicon AFM probe in the tapping mode was chosen for the subsequent measurements due to its temperature insensitivi...

  16. Conventional and rapid thermal annealing of spray pyrolyzed copper indium gallium sulfide thin films

    International Nuclear Information System (INIS)

    Aydin, Erkan; Sankir, Mehmet; Sankir, Nurdan Demirci

    2014-01-01

    Highlights: • Spray pyrolysis of copper indium gallium sulfide (CuInGaS 2 ) thin films. • Environmentally friendly method to produce solar cell quality absorber layers. • Effects of post-annealing process on the film properties of CuInGaS 2 . • Pros-and-cons of conventional and rapid thermal annealing. • Enhanced electrical and optical properties via annealing. - Abstract: With this study for the first time effects of post annealing on morphological, structural, optical and electrical properties of spray pyrolyzed copper–indium–gallium–sulfide (CuInGaS 2 ) thin films have been investigated. Pros-and-cons of conventional (CA) and rapid thermal annealing (RTA) have been discussed to obtain the high quality thin film absorbers for solar cell applications. X-ray diffraction analysis revealed that all of the spray pyrolyzed CuInGaS 2 thin films have chalcopyrite structures with a highly (1 1 2) preferential orientation. Raman spectra also confirmed this structure. However, metal oxide secondary phases such as copper oxide and gallium oxide were detected when the temperature ramp rate was increased during RTA process. Energy dispersive X-ray measurements revealed that both copper and gallium diffused through the surface after annealing processes. Moreover, copper diffusion became pronounced especially at high annealing temperatures. Optical transmission measurements in the wavelength range between 600 and 1100 nm showed that band gap energy of CuInGaS 2 thin films was ranging between 1.36 and 1.51 eV depending on the annealing conditions. Very high mobility values have been observed for both processes. The maximum electrical mobility, 30.9 cm 2 /V s, was observed for the films annealed at 600 °C via CA. This is the highest reported value among the CuInGaS 2 thin film absorbers deposited by both solution and vacuum based techniques. As a result, post-annealing of spray pyrolyzed CuInGaS 2 thin films without usage of highly toxic gases, reported in this

  17. Doping dependence of electrical and thermal conductivity of nanoscale polyaniline thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jin Jiezhu; Wang Qing [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Haque, M A [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2010-05-26

    We performed simultaneous characterization of electrical and thermal conductivity of 55 nm thick polyaniline (PANI) thin films doped with different levels of camphor sulfonic acids (CSAs). The effect of the doping level is more pronounced on electrical conductivity than on thermal conductivity of PANIs, thereby greatly affecting their ratio that determines the thermoelectric efficiency. At the 60% (the molar ratio of CSA to phenyl-N repeat unit of PANI) doping level, PANI exhibited the maximum electrical and thermal conductivity due to the formation of mostly delocalized structures. Whereas polarons are the charge carriers responsible for the electrical conduction, phonons are believed to play a dominant role in the heat conduction in nanoscale doped PANI thin films.

  18. Designing of long wavelength cut thin film filter for temperature reduction of concentrator photovoltaic

    Directory of Open Access Journals (Sweden)

    Ahmad Nawwar

    2016-01-01

    Full Text Available This paper presents a comparison of three-dimensional simulation for concentrator photovoltaic module using two types of multi-junction solar cell. Each had its own range of spectral response and based on that range a thin film filter was developed for each case to reflect the unused spectral of the solar spectrum and allowed the desired spectrum to reach the solar cell. The thin film was deposited on a secondary optical element that was used to homogenize the irradiance distribution on the solar cell. A thermal simulation was conducted to compare the resulted decrease in cell temperature due to the use of the thin film for each case.

  19. Thermal rectification in thin films driven by gradient grain microstructure

    Science.gov (United States)

    Cheng, Zhe; Foley, Brian M.; Bougher, Thomas; Yates, Luke; Cola, Baratunde A.; Graham, Samuel

    2018-03-01

    As one of the basic components of phononics, thermal rectifiers transmit heat current asymmetrically similar to electronic rectifiers in microelectronics. Heat can be conducted through them easily in one direction while being blocked in the other direction. In this work, we report a thermal rectifier that is driven by the gradient grain structure and the inherent gradient in thermal properties as found in these materials. To demonstrate their thermal rectification properties, we build a spectral thermal conductivity model with complete phonon dispersion relationships using the thermophysical properties of chemical vapor deposited (CVD) diamond films which possess gradient grain microstructures. To explain the observed significant thermal rectification, the temperature and thermal conductivity distribution are studied. Additionally, the effects of temperature bias and film thickness are discussed, which shed light on tuning the thermal rectification based on the gradient microstructures. Our results show that the columnar grain microstructure makes CVD materials unique candidates for mesoscale thermal rectifiers without a sharp temperature change.

  20. Structural changes in nanocrystalline Bi2Te3/Bi2Se3 multilayer thin films caused by thermal annealing

    Science.gov (United States)

    Hamada, Jun; Takashiri, Masayuki

    2017-06-01

    To assess the performance of thermoelectric devices with nanostructured materials at high operating temperatures, we investigated the effects of structural changes on the thermoelectric properties of nanocrystalline bismuth telluride (Bi2Te3)/bismuth selenide (Bi2Se3) multilayer thin films caused by thermal annealing. Multilayer thin films with 12 and 48 layers were fabricated by radio-frequency magnetron sputtering. These thin films were then thermally annealed at temperatures ranging from 250 to 350 °C. As the annealing temperature increased, flake-like nanocrystals were grown in the 12- and 48-layer thin films. X-ray diffraction peaks from three alloys, which were determined to be Bi2Te3, Bi2Se3, and (Bi2Te3)0.4(Bi2Se3)0.6, were observed in the thin films. This indicates that Bi2Te3 and Bi2Se3 layers were not completely diffused mutually in this range of annealing temperature. The 12- and 48-layer thin films exhibited increases in both the electrical conductivity and the absolute value of the Seebeck coefficient at the annealing temperature of 300 °C. One possible explanation for this improvement is that the band structure is tuned by inducing strain during the variation of atomic composition in the multilayer thin films. As a result, the power factor was significantly improved by the thermal annealing. In particular, the maximum power factor reached 13.7 μW/(cm K2) in the 12-layer thin film at the annealing temperature of 350 °C. Therefore, we may conclude that if the multilayer thin films undergo structural changes at higher operating temperature (≈350 °C), thermoelectric devices composed of multilayer thin films are expected to exhibit suitable thermoelectric performance.

  1. Thermal conductivity of silicon nanocrystals and polystyrene nanocomposite thin films

    International Nuclear Information System (INIS)

    Juangsa, Firman Bagja; Muroya, Yoshiki; Nozaki, Tomohiro; Ryu, Meguya; Morikawa, Junko

    2016-01-01

    Silicon nanocrystals (SiNCs) are well known for their size-dependent optical and electronic properties; they also have the potential for low yet controllable thermal properties. As a silicon-based low-thermal conductivity material is required in microdevice applications, SiNCs can be utilized for thermal insulation. In this paper, SiNCs and polymer nanocomposites were produced, and their thermal conductivity, including the density and specific heat, was measured. Measurement results were compared with thermal conductivity models for composite materials, and the comparison shows a decreasing value of the thermal conductivity, indicating the effect of the size and presence of the nanostructure on the thermal conductivity. Moreover, employing silicon inks at room temperature during the fabrication process enables a low cost of fabrication and preserves the unique properties of SiNCs. (paper)

  2. 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.

  3. CdS thin films obtained by thermal treatment of cadmium(II) complex precursor deposited by MAPLE technique

    International Nuclear Information System (INIS)

    Rotaru, Andrei; Mietlarek-Kropidlowska, Anna; Constantinescu, Catalin; Scarisoreanu, Nicu; Dumitru, Marius; Strankowski, Michal; Rotaru, Petre; Ion, Valentin; Vasiliu, Cristina; Becker, Barbara; Dinescu, Maria

    2009-01-01

    Thin films of [Cd{SSi(O-Bu t ) 3 }(S 2 CNEt 2 )] 2 , precursor for semiconducting CdS layers, were deposited on silicon substrates by Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique. Structural analysis of the obtained films by Fourier transform infrared spectroscopy (FTIR) confirmed the viability of the procedure. After the deposition of the coordination complex, the layers are manufactured by appropriate thermal treatment of the system (thin film and substrate), according to the thermal analysis of the compound. Surface morphology of the thin films was investigated by atomic force microscopy (AFM) and spectroscopic-ellipsometry (SE) measurements.

  4. Thermal stability of gold-PS nanocomposites thin films

    Indian Academy of Sciences (India)

    Administrator

    an improved thermal stability of the polystyrene (PS) composite film much above its glass transition tempera- ture. Keywords. Thermal stability; polymer nanocomposites; low temperature .... The color of the solution changed immediately from pale yellow to black upon the addition. The reaction mix- ture was stirred for 2 h ...

  5. APCVD hexagonal boron nitride thin films for passive near-junction thermal management of electronics

    Science.gov (United States)

    KC, Pratik; Rai, Amit; Ashton, Taylor S.; Moore, Arden L.

    2017-12-01

    The ability of graphene to serve as an ultrathin heat spreader has been previously demonstrated with impressive results. However, graphene is electrically conductive, making its use in contact with electronic devices problematic from a reliability and integration perspective. As an alternative, hexagonal boron nitride (h-BN) is a similarly structured material with large in-plane thermal conductivity but which possesses a wide band gap, thereby giving it potential to be utilized for directing contact, near-junction thermal management of electronics without shorting or the need for an insulating intermediate layer. In this work, the viability of using large area, continuous h-BN thin films as direct contact, near-junction heat spreaders for electronic devices is experimentally evaluated. Thin films of h-BN several square millimeters in size were synthesized via an atmospheric pressure chemical vapor deposition (APCVD) method that is both simple and scalable. These were subsequently transferred onto a microfabricated test device that simulated a multigate transistor while also allowing for measurements of the device temperature at various locations via precision resistance thermometry. Results showed that these large-area h-BN films with thicknesses of 77–125 nm are indeed capable of significantly lowering microdevice temperatures, with the best sample showing the presence of the h-BN thin film reduced the effective thermal resistance by 15.9% ± 4.6% compared to a bare microdevice at the same power density. Finally, finite element simulations of these experiments were utilized to estimate the thermal conductivity of the h-BN thin films and identify means by which further heat spreading performance gains could be attained.

  6. FABRICATION OF Cu-Al-Ni SHAPE MEMORY THIN FILM BY THERMAL EVOPRATION

    OpenAIRE

    Özkul, İskender; Canbay, Canan Aksu; Tekataş, Ayşe

    2017-01-01

    Among the functional, materials shape memory alloysare important because of their unique properties. So, these materials haveattracted more attention to be used in micro/nano electronic andelectromechanic systems. In this work, thermal evaporation method has been usedto produce CuAlNi shape memory alloy thin film. The produced CuAlNi thin filmhas been characterized and the presence of the martensite phase wasinvestigated and compared with the CuAlNi alloy sample. CuAlNi shape memoryalloy thin...

  7. Thermal Conductivity of ZIF-8 Thin-Film under Ambient Gas Pressure.

    Science.gov (United States)

    Cui, Boya; Audu, Cornelius O; Liao, Yijun; Nguyen, SonBinh T; Farha, Omar K; Hupp, Joseph T; Grayson, Matthew

    2017-08-30

    Thermal conductivity is a crucial parameter for managing exothermal gas adsorption in metal organic frameworks (MOFs), but experimental studies have been limited. In this work, the thermal conductivity of a zeolitic imidazolate framework ZIF-8 was experimentally determined on thin films using the 3ω technique at different partial pressures in perfluorohexane, nitrogen, air, and vacuum ambients at 300 K. In contrast to theoretical prediction, the thermal conductivity κ = 0.326 ± 0.002 W/m K was approximately independent of ambient gas species and pressure from atmospheric pressure to vacuum. This work introduces a useful approach for probing MOF thermal conductivity under gas adsorption.

  8. A Hot-Stage Atomic Force Microscope for the Measurement of Plastic Deformation in Metallic Thin Films During Thermal Cycling

    National Research Council Canada - National Science Library

    Shultz, Thomas

    2001-01-01

    .... The system will allow future in-situ thermal cycling experiments on microelectronic devices in a protected environment to provide insight into the role of plastic deformation in metallic thin films...

  9. Thermal Characteristics of Multilayer Insulation Materials for Flexible Thin-Film Solar Cell Array of Stratospheric Airship

    Directory of Open Access Journals (Sweden)

    Kangwen Sun

    2014-01-01

    Full Text Available Flexible thin-film solar cell is an efficient energy system on the surface of stratospheric airship for utilizing the solar energy. In order to ensure the normal operation of airship platform, the thermal control problem between the flexible thin-film solar cell and the airship envelope should be properly resolved. In this paper, a multilayer insulation material (MLI is developed first, and low temperature environment test is carried out to verify the insulation effect of MLI. Then, a thermal heat transfer model of flexible thin-film solar cell and MLI is proposed, and the equivalent thermal conductivity coefficients of flexible thin-film solar cell and Nomex honeycomb are calculated based on the environment test and the temperature profile of flexible thin-film solar cell versus each layer of MLI. Finally, FLUENT is used for modeling and simulation analysis on the flexible thin-film solar cell and MLI, and the simulation results agree well with the experimental data, which validate the correctness of the proposed heat transfer model of MLI. In some way, our study can provide helpful support for further engineering applications of flexible thin-film solar cell.

  10. Structural, electrical, and optical properties of copper indium diselenide thin film prepared by thermal evaporation method

    Energy Technology Data Exchange (ETDEWEB)

    Shah, N.M.; Ray, J.R.; Patel, K.J.; Kheraj, V.A.; Desai, M.S. [Applied Physics Department, Faculty of Technology and Engineering, M. S. University of Baroda, Vadodara-390001, Gujarat (India); Panchal, C.J., E-mail: cjpanchal_msu@yahoo.co [Applied Physics Department, Faculty of Technology and Engineering, M. S. University of Baroda, Vadodara-390001, Gujarat (India); Rehani, Bharti [Metallurgical Engineering Department, Faculty of Technology and Engineering, M. S. University of Baroda, Vadodara-390001, Gujarat (India)

    2009-05-01

    Stoichiometric compound of copper indium diselenide (CuInSe{sub 2}) was synthesized by direct reaction of high-purity elemental copper, indium and selenium in an evacuated quartz ampoule. The phase structure and composition of the synthesized pulverized material analyzed by X-ray diffraction (XRD) and energy dispersive analysis of X-rays (EDAX) revealed the chalcopyrite structure and stoichiometry of elements. Thin films of CuInSe{sub 2} were deposited onto organically cleaned soda lime glass substrates held at different temperatures (i.e. 300 K to 573 K) using thermal evaporation technique. CuInSe{sub 2} thin films were then thermally annealed in a vacuum chamber at 573 K at a base pressure of 10{sup -2} mbar for 1 h. The effect of substrate temperature (T{sub s}) and thermal annealing (T{sub a}) on structural, compositional, morphological, optical and electrical properties of films were investigated using XRD, transmission electron microscopy, EDAX, atomic force microscopy (AFM), optical transmission measurements and Hall effect techniques. XRD and EDAX studies of CuInSe{sub 2} thin films revealed that the films deposited in the substrate temperature range of 423-573 K have preferred orientation of grains along the (112) plane and near stoichiometric composition. AFM analysis indicates that the grain size increases with increase of T{sub s} and T{sub a}. Optical and electrical characterizations of films suggest that CuInSe{sub 2} thin films have high absorption coefficient (10{sup 4} cm{sup -1}) and resistivity value in the interval 10{sup -2}-10{sup 1} {Omega} cm influenced by T{sub s} and T{sub a}.

  11. Effects of Mev Si Ions and Thermal Annealing on Thermoelectric and Optical Properties of SiO2/SiO2+Ge Multi-nanolayer thin Films

    Science.gov (United States)

    Budak, S.; Alim, M. A.; Bhattacharjee, S.; Muntele, C.

    Thermoelectric generator devices have been prepared from 200 alternating layers of SiO2/SiO2+Ge superlattice films using DC/RF magnetron sputtering. The 5 MeV Si ionsbombardmenthasbeen performed using the AAMU Pelletron ion beam accelerator to formquantum dots and / or quantum clusters in the multi-layer superlattice thin films to decrease the cross-plane thermal conductivity, increase the cross-plane Seebeck coefficient and increase the cross-plane electrical conductivity to increase the figure of merit, ZT. The fabricated devices have been annealed at the different temperatures to tailor the thermoelectric and optical properties of the superlattice thin film systems. While the temperature increased, the Seebeck coefficient continued to increase and reached the maximum value of -25 μV/K at the fluenceof 5x1013 ions/cm2. The decrease in resistivity has been seen between the fluence of 1x1013 ions/cm2 and 5x1013 ions/cm2. Transport properties like Hall coefficient, density and mobility did not change at all fluences. Impedance spectroscopy has been used to characterize the multi-junction thermoelectric devices. The loci obtained in the C*-plane for these data indicate non-Debye type relaxation displaying the presence of the depression parameter.

  12. Temperature dependent thermal conductivity and transition mechanism in amorphous and crystalline Sb2Te3 thin films.

    Science.gov (United States)

    Li, Qisong; Wei, Jingsong; Sun, Hao; Zhang, Kui; Huang, Zhengxing; Zhang, Long

    2017-10-23

    Sb 2 Te 3 thin films are widely used in high density optical and electronic storage, high-resolution greyscale image recording, and laser thermal lithography. Thermal conductivity and its temperature dependence are critical factors that affect the application performance of thin films. This work aims to evaluate the temperature dependence of thermal conductivity of crystalline and amorphous Sb 2 Te 3 thin films experimentally and theoretically, and explores into the corresponding mechanism of heat transport. For crystalline Sb 2 Te 3 thin films, the thermal conductivity was found to be 0.35 ± 0.035 W m -1 K -1 and showed weak temperature dependence. The thermal conductivity of amorphous Sb 2 Te 3 thin films at temperatures below ~450 K is about 0.23 ± 0.023 W m -1 K -1 , mainly arising from the lattice as the electronic contribution is negligible; at temperatures above 450 K, the thermal conductivity experiences an abrupt increase owing to the structural change from amorphous to crystalline state. The work can provide an important guide and reference to the real applications of Sb 2 Te 3 thin films.

  13. Structural, optical and XPS study of thermal evaporated In2O3 thin films

    Science.gov (United States)

    Neelakanta Reddy, I.; Venkata Reddy, Ch; Cho, Migyung; Shim, Jaesool; Kim, Dongseob

    2017-08-01

    The nanostructured In2O3 thin films were deposited on Si n-type (1 0 0) substrates by reactive thermal evaporation. The structural, morphological, and oxidation states of the films were investigated using x-ray diffraction, scanning electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. The optical properties of the films were analyzed by UV-vis spectroscopy, Raman spectroscopy, and photoluminescence spectroscopy. The deposited films showed c-In2O3 crystalline nanostructures with a preferred diffraction peak of (2 2 2). The truncated icosahedron shape’s morphology with a transmittance of 85% was observed in the In2O3 thin films. All the deposited indium oxide films have 3+  oxidation states.

  14. Operation of a Thin-Film Inflatable Concentrator System Demonstrated in a Solar Thermal Vacuum Environment

    Science.gov (United States)

    Wong, Wayne A.

    2002-01-01

    Thin-film inflatable solar concentrators offer significant advantages in comparison to stateof- the-art rigid panel concentrators, including low weight, low stowage volume, and simple gas deployment. From June 10 to 22, 2001, the ElectroMagnetic Radiation Control Experiment (EMRCE) Team used simulated solar energy to demonstrate the operation of an inflatable concentrator system at NASA Glenn Research Center's Tank 6 thermal vacuum facility. The joint Government/industry test team was composed of engineers and technicians from Glenn, the Air Force Research Laboratory, SRS Technologies, and ATK Thiokol Propulsion. The research hardware consisted of the following: 1) A thin-film inflatable concentrator; 2) The hexapod pointing and focus control system; 3) Two rigidized support struts using two candidate technologies - ultraviolet-rigidized glass and radiation-cured isographite.

  15. Thermal stability of gold-PS nanocomposites thin films

    Indian Academy of Sciences (India)

    Administrator

    performed at liquid nitrogen temperatures to reduce the electron–beam-induced radiation damage. The results showed a marginal increase in Au nanoparticle diameter (2⋅3 nm–3⋅6 nm) and more importantly, an improved thermal stability of the polystyrene (PS) composite film much above its glass transition tempera- ture.

  16. Roughness effects on the thermal stability of thin films

    NARCIS (Netherlands)

    Palasantzas, George

    1997-01-01

    In this work, we investigate interface roughness effects on the energetic terms that play a key role on the thermal stability of thin silicide films. The roughness is modeled as a self-affine structure with power spectrum ~σ^2ξ^2(1+aq^2ξ^2)^-1-H convoluted with a domain size distribution ∝

  17. Thermal Characterization of Thin Films for MEMS Applications

    National Research Council Canada - National Science Library

    Howe, David J; Morgan, Brian

    2008-01-01

    ...). Two such dielectrics that are used widely are silicon dioxide (SiO2) and photoresist. As a large portion of these systems use the conduction of heat through SiO2 and photoresist layers, the thermal conductivity of these materials is crucial...

  18. Effect of thermal annealing on structural and optical properties of In2S3 thin films

    Science.gov (United States)

    Choudhary, Sonu

    2015-08-01

    There is a highly need of an alternate of toxic materials CdS for solar cell applications and indium sulfide is found the most suitable candidate to replace CdS due to its non-toxic and environmental friendly nature. In this paper, the effect of thermal annealing on the structural and optical properties of indium sulfide (In2S3) thin films is undertaken. The indium sulfide thin films of 121 nm were deposited on glass substrates employing thermal evaporation method. The films were subjected to the X-ray diffractometer and UV-Vis spectrophotometer respectively for structural and optical analysis. The XRD pattern show that the as-deposited thin film was amorphous in nature and crystallinity is found to be varied with annealing temperature. The optical analysis reveals that the optical band gap is varied with annealing. The optical parameters like absorption coefficient, extinction coefficient and refractive index were calculated. The results are in good agreement with available literature.

  19. Thermal oxidation of Zr–Cu–Al–Ni amorphous metal thin films

    Energy Technology Data Exchange (ETDEWEB)

    Oleksak, R.P.; Hostetler, E.B.; Flynn, B.T. [School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331 (United States); McGlone, J.M.; Landau, N.P.; Wager, J.F. [School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331 (United States); Stickle, W.F. [Hewlett-Packard Company, Corvallis, OR 97333 (United States); Herman, G.S., E-mail: greg.herman@oregonstate.edu [School of Chemical, Biological and Environmental Engineering, Oregon State University, Corvallis, OR 97331 (United States)

    2015-11-30

    The initial stages of thermal oxidation for Zr–Cu–Al–Ni amorphous metal thin films were investigated using X-ray photoelectron spectroscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The as-deposited films had oxygen incorporated during sputter deposition, which helped to stabilize the amorphous phase. After annealing in air at 300 °C for short times (5 min) this oxygen was found to segregate to the surface or buried interface. Annealing at 300 °C for longer times leads to significant composition variation in both vertical and lateral directions, and formation of a surface oxide layer that consists primarily of Zr and Al oxides. Surface oxide formation was initially limited by back-diffusion of Cu and Ni (< 30 min), and then by outward diffusion of Zr (> 30 min). The oxidation properties are largely consistent with previous observations of Zr–Cu–Al–Ni metallic glasses, however some discrepancies were observed which could be explained by the unique sample geometry of the amorphous metal thin films. - Highlights: • Thermal oxidation of amorphous Zr–Cu–Al–Ni thin films was investigated. • Significant short-range inhomogeneities were observed in the amorphous films. • An accumulation of Cu and Ni occurs at the oxide/metal interface. • Diffusion of Zr was found to limit oxide film growth.

  20. Structural, Optical, and Dielectric Properties of Azure B Thin Films and Impact of Thermal Annealing

    Science.gov (United States)

    Zeyada, H. M.; Zidan, H. M.; Abdelghany, A. M.; Abbas, I.

    2017-07-01

    Thin films of azure B (AB) have been prepared by thermal evaporation. Structural, optical, and dielectric characteristics of as-prepared and annealed samples were studied. AB is polycrystalline in as-synthesized powder form. Detailed x-ray diffraction studies showed amorphous structure for pristine and annealed films. Fourier-transform infrared vibrational spectroscopy indicated minor changes in molecular bonds of AB thin films either after deposition or after thermal annealing. Optical transmittance and reflection spectra of prepared thin films were studied at nearly normal light incidence in the spectral range from 200 nm to 2500 nm, showing marked changes without new peaks. Annealing increased the absorption coefficient and decreased the optical bandgap. Onset and optical energy gaps of pristine films were found to obey indirect allowed transition with values of 1.10 eV and 2.64 eV, respectively. Annealing decreased the onset and optical energy gaps to 1.0 eV and 2.57 eV, respectively. The dispersion parameters before and after annealing are discussed in terms of a single-oscillator model. The spectra of the dielectric constants ( ɛ 1, ɛ 2) were found to depend on the annealing temperature in addition to the incident photon energy.

  1. Tuning the Anisotropy of In-Plane Thermal Conduction in Thin Films by Modulating Thickness

    Science.gov (United States)

    Zeng, Yuqiang; Marconnet, Amy

    2018-01-01

    Anisotropy in thermal conductivity is promising for directing the heat-flow pathways in modern applications including thermal management of electronic devices. While some materials, like graphite, have strong anisotropy when comparing the in-plane thermal conductivity to cross-plane thermal conductivity, few naturally occurring materials have significant anisotropy within the in-plane directions, with an anisotropy ratio of ˜3 in few-layer black phosphorus being among the highest. In this Letter, we propose to control the thermal-conduction anisotropy by periodically modulating the thickness of thin films. Specifically, we model the thermal conduction in silicon-based thickness-modulated films using full three-dimensional simulations based on the phonon frequency-dependent Boltzmann transport equation. Our simulations demonstrate that phonon scattering with appropriately sized and shaped thickness-modulation features leads to a significant anisotropy in thermal conduction. In the diffusive regime, the same types of features lead to relatively low anisotropy (as calculated using the conventional heat diffusion equation). Thus, the enhanced thermal-conduction anisotropy with small features comes from the phonon scattering and size effects. Modulating the thickness of the thin films allows tuning the thermal-anisotropy ratio across an order of magnitude. Moreover, the proposed structures can be fabricated with currently available silicon-based nanofabrication techniques, without the need for exotic or expensive materials.

  2. Comparison of structural properties of thermally evaporated CdTe thin films on different substrates

    International Nuclear Information System (INIS)

    Tariq, G.H.; Anis-ur-Rehman, M.

    2011-01-01

    The direct energy band gap in the range of 1.5 eV and the high absorption coefficient (105 cm/sup -1/) makes Cadmium Telluride (CdTe) a suitable material for fabrication of thin film solar cells. Thin film solar cells based on CdTe (1 cm area) achieved efficiency of 15.6% on a laboratory scale. CdTe thin films were deposited by thermal evaporation technique under vacuum 2 X 10/sup -5/mbar on glass and stainless steel (SS) substrates. During deposition substrates temperature was kept same at 200 deg. C for all samples. The structural properties were determined by the X-ray Diffraction (XRD) patterns. All samples exhibit polycrystalline nature. Dependence of different structural parameters such as lattice parameter, micro strain, and grain size and dislocation density on thickness was studied. Also the influence of the different substrates on these parameters was investigated. The analysis showed that the preferential orientation of films was dependent on the substrate type. (author)

  3. Read/write simulation of thermally stabilized magnetic recording media with a thin film head

    International Nuclear Information System (INIS)

    Takanosu, S.; Abe, T.; Yoneyama, Y.; Fujiwara, N.; Shinagawa, K.

    2004-01-01

    In order to study the thermal stability of an antiferromagnetically coupled medium and a keepered one with a soft magnetic underlayer, a finite element read/write simulation based on the Poisson equation is performed on the 2D model of the medium and a thin film head system. The model used for the recording layer is a Stoner-Wohlfarth model extended at finite temperatures. As a result, it is found that both media have high thermal stability compared with the conventional medium

  4. Influence of thermal annealing on microstructural, morphological, optical properties and surface electronic structure of copper oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Akgul, Funda Aksoy, E-mail: fundaaksoy01@gmail.com [Department of Physics, Nigde University, 51240 Nigde (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Akgul, Guvenc, E-mail: guvencakgul@gmail.com [Bor Vocational School, Nigde University, 51700 Nigde (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Yildirim, Nurcan [Department of Physics Engineering, Ankara University, 06100 Ankara (Turkey); Department of Metallurgical and Materials Engineering, Middle East Technical University, 06800 Ankara (Turkey); Unalan, Husnu Emrah [Department of Metallurgical and Materials Engineering, Middle East Technical University, 06800 Ankara (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey); Turan, Rasit [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey); Center for Solar Energy Research and Applications, Middle East Technical University, 06800 Ankara (Turkey)

    2014-10-15

    In this study, effect of the post-deposition thermal annealing on copper oxide thin films has been systemically investigated. The copper oxide thin films were chemically deposited on glass substrates by spin-coating. Samples were annealed in air at atmospheric pressure and at different temperatures ranging from 200 to 600°C. The microstructural, morphological, optical properties and surface electronic structure of the thin films have been studied by diagnostic techniques such as X-ray diffraction (XRD), Raman spectroscopy, ultraviolet–visible (UV–VIS) absorption spectroscopy, field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The thickness of the films was about 520 nm. Crystallinity and grain size was found to improve with annealing temperature. The optical bandgap of the samples was found to be in between 1.93 and 2.08 eV. Cupric oxide (CuO), cuprous oxide (Cu{sub 2}O) and copper hydroxide (Cu(OH){sub 2}) phases were observed on the surface of as-deposited and 600 °C annealed thin films and relative concentrations of these three phases were found to depend on annealing temperature. A complete characterization reported herein allowed us to better understand the surface properties of copper oxide thin films which could then be used as active layers in optoelectronic devices such as solar cells and photodetectors. - Highlights: • Effect of post-deposition annealing on copper oxide thin films was investigated. • Structural, optical, and electronic properties of the thin films were determined. • Oxidation states of copper oxide thin films were confirmed by XPS analysis. • Mixed phases of CuO and Cu{sub 2}O were found to coexist in copper oxide thin films.

  5. Development of In-plane Thermal Conductivity Calculation Methods in Thin Films

    Directory of Open Access Journals (Sweden)

    A. A. Barinov

    2017-01-01

    Full Text Available The future nanoelectronics development involves using the smaller- -and-smaller-sized circuit components based on the micro- and nanostructures. This causes a growth of the specific heat flows up to 100 W/cm2. Since performance of electronic devices is strongly dependent on the temperature there is a challenge to create the heat transfer models, which take into account the size effect and ensure a reliable estimate of the thermal conductivity. This is one of the crucial tasks for development of new generations of integrated circuits.The paper studies heat transfer processes using the silicon thin films as an example. Thermal conductivity calculations are performed taking into account the influence of the classical size effect in the context of the Sondheimer model based on the solution of the Boltzmann transport equation.The paper, for the first time, presents and considers the influence of various factors on the thermal conductivity of thin films, namely temperature, film thickness, polarization of the phonon waves (transverse and longitudinal, velocity and relaxation time versus frequency for the phonons of different wave types.Based on the analysis, three models with different accuracy are created to estimate the influence of detailing processes under consideration on the thermal conductivity in a wide range of temperatures (from 10 K to 450 К and film thickness (from 10 nm to 100 µm.So in the model I for the first time in calculating thermal conductivity of thin films we properly and circumstantially take into account the dependence of the velocity and the relaxation time of phonons on the frequency and polarization. The obtained values are in a good agreement with available experimental data and theoretical models of other authors. In the following models we use few average methods for relaxation times and velocities, which leads to significant reduction in calculating accuracy up to the values exceeding 100%.Therefore, when calculating

  6. Growth, structural and optical properties of copper indium diselenide thin films deposited by thermal evaporation method

    Energy Technology Data Exchange (ETDEWEB)

    Shah, N.M.; Panchal, C.J.; Kheraj, V.A.; Ray, J.R.; Desai, M.S. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara 390001, Gujarat (India)

    2009-05-15

    Copper indium diselenide (CuInSe{sub 2}) compound was synthesized by reacting its constituent's elements copper, indium and selenium in near stoichiometric proportions (i.e. 1:1:2 with 5% excess selenium) in an evacuated quartz ampoule. Synthesized pulverized compound material was used as an evaporant material to deposit thin films of CuInSe{sub 2} onto organically cleaned sodalime glass substrates, held at different temperatures (300-573 K), by means of single source thermal evaporation method. The phase structure and the composition of chemical constituents present in the synthesized compound and thin films have been investigated using X-ray diffraction and energy dispersive X-ray analysis, respectively. The investigations show that CuInSe{sub 2} thin films grown above 423 K are single phase, having preferred orientation of grains along the (112) direction, and having near stoichiometric composition of elements. The surface morphology of CuInSe{sub 2} films, deposited at different substrate temperatures, has been studied using the atomic force microscopy to estimate its surface roughness. An analysis of the transmission spectra of CuInSe{sub 2} films, recorded in the wavelength range of 500-1500 nm, revealed that the optical absorption coefficient and the energy band gap for CuInSe{sub 2} films, deposited at different substrate temperatures, are {proportional_to}10{sup 4} cm{sup -1} and 1.01-1.06 eV, respectively. The transmission spectrum was analyzed using iterative method to calculate the refractive index and the extinction coefficient of CuInSe{sub 2} thin film deposited at 523 K. The Hall effect measurements and the temperature dependence of the electrical conductivity of CuInSe{sub 2} thin films, deposited at different substrate temperatures, revealed that the films had electrical resistivity in the range of 0.15-20 ohm cm, and the activation energy 82-42 meV, both being influenced by the substrate temperature. (author)

  7. Preparation of InSe Thin Films by Thermal Evaporation Method and Their Characterization: Structural, Optical, and Thermoelectrical Properties

    Directory of Open Access Journals (Sweden)

    Sarita Boolchandani

    2018-01-01

    Full Text Available The indium selenium (InSe bilayer thin films of various thickness ratios, InxSe(1-x (x = 0.25, 0.50, 0.75, were deposited on a glass substrate keeping overall the same thickness of 2500 Ǻ using thermal evaporation method under high vacuum atmosphere. Electrical, optical, and structural properties of these bilayer thin films have been compared before and after thermal annealing at different temperatures. The structural and morphological characterization was done using XRD and SEM, respectively. The optical bandgap of these thin films has been calculated by Tauc’s relation that varies within the range of 1.99 to 2.05 eV. A simple low-cost thermoelectrical power measurement setup is designed which can measure the Seebeck coefficient “S” in the vacuum with temperature variation. The setup temperature variation is up to 70°C. This setup contains a Peltier device TEC1-12715 which is kept between two copper plates that act as a reference metal. Also, in the present work, the thermoelectric power of indium selenide (InSe and aluminum selenide (AlSe bilayer thin films prepared and annealed in the same way is calculated. The thermoelectric power has been measured by estimating the Seebeck coefficient for InSe and AlSe bilayer thin films. It was observed that the Seebeck coefficient is negative for InSe and AlSe thin films.

  8. Measurements of thermal conductivity and the coefficient of thermal expansion for polysilicon thin films by using double-clamped beams

    Science.gov (United States)

    Liu, Haiyun; Wang, Lei

    2018-01-01

    In this paper, a test structure for simultaneously determining thermal conductivity and the coefficient of thermal expansion (CTE) of polysilicon thin film is proposed. The test structure consists of two double-clamped beams with different lengths. A theoretical model for extracting thermal conductivity and CTE based on electrothermal analysis and resonance frequency approach is developed. Both flat and buckled beams are considered in the theoretical model. The model is confirmed by finite element software ANSYS. The test structures are fabricated by surface micromachined fabrication process. Experiments are carried out in our atmosphere. Thermal conductivity and CTE of polysilicon thin film are obtained to be (29.96  ±  0.92) W · m · K-1 and (2.65  ±  0.03)  ×  10-6 K-1, respectively, with temperature ranging from 300-400 K.

  9. Phonon and thermal properties of exfoliated TaSe{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Z.; Jiang, C.; Renteria, J. [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Pope, T. R.; Tsang, C. F.; Stickney, J. L.; Salguero, T. T., E-mail: salguero@uga.edu, E-mail: balandin@ee.ucr.edu [Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States); Goli, P. [Materials Science and Engineering Program, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Balandin, A. A., E-mail: salguero@uga.edu, E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States); Materials Science and Engineering Program, Bourns College of Engineering, University of California–Riverside, Riverside, California 92521 (United States)

    2013-11-28

    We report on the phonon and thermal properties of thin films of tantalum diselenide (2H-TaSe{sub 2}) obtained via the “graphene-like” mechanical exfoliation of crystals grown by chemical vapor transport. The ratio of the intensities of the Raman peak from the Si substrate and the E{sub 2g} peak of TaSe{sub 2} presents a convenient metric for quantifying film thickness. The temperature coefficients for two main Raman peaks, A{sub 1g} and E{sub 2g}, are −0.013 and −0.0097 cm{sup −1}/{sup o}C, respectively. The Raman optothermal measurements indicate that the room temperature thermal conductivity in these films decreases from its bulk value of ∼16 W/mK to ∼9 W/mK in 45-nm thick films. The measurement of electrical resistivity of the field-effect devices with TaSe{sub 2} channels shows that heat conduction is dominated by acoustic phonons in these van der Waals films. The scaling of thermal conductivity with the film thickness suggests that the phonon scattering from the film boundaries is substantial despite the sharp interfaces of the mechanically cleaved samples. These results are important for understanding the thermal properties of thin films exfoliated from TaSe{sub 2} and other metal dichalcogenides, as well as for evaluating self-heating effects in devices made from such materials.

  10. Phonon and thermal properties of exfoliated TaSe2 thin films

    International Nuclear Information System (INIS)

    Yan, Z.; Jiang, C.; Renteria, J.; Pope, T. R.; Tsang, C. F.; Stickney, J. L.; Salguero, T. T.; Goli, P.; Balandin, A. A.

    2013-01-01

    We report on the phonon and thermal properties of thin films of tantalum diselenide (2H-TaSe 2 ) obtained via the “graphene-like” mechanical exfoliation of crystals grown by chemical vapor transport. The ratio of the intensities of the Raman peak from the Si substrate and the E 2g peak of TaSe 2 presents a convenient metric for quantifying film thickness. The temperature coefficients for two main Raman peaks, A 1g and E 2g , are −0.013 and −0.0097 cm −1 / o C, respectively. The Raman optothermal measurements indicate that the room temperature thermal conductivity in these films decreases from its bulk value of ∼16 W/mK to ∼9 W/mK in 45-nm thick films. The measurement of electrical resistivity of the field-effect devices with TaSe 2 channels shows that heat conduction is dominated by acoustic phonons in these van der Waals films. The scaling of thermal conductivity with the film thickness suggests that the phonon scattering from the film boundaries is substantial despite the sharp interfaces of the mechanically cleaved samples. These results are important for understanding the thermal properties of thin films exfoliated from TaSe 2 and other metal dichalcogenides, as well as for evaluating self-heating effects in devices made from such materials

  11. Phonon and thermal properties of exfoliated TaSe2 thin films

    Science.gov (United States)

    Yan, Z.; Jiang, C.; Pope, T. R.; Tsang, C. F.; Stickney, J. L.; Goli, P.; Renteria, J.; Salguero, T. T.; Balandin, A. A.

    2013-11-01

    We report on the phonon and thermal properties of thin films of tantalum diselenide (2H-TaSe2) obtained via the "graphene-like" mechanical exfoliation of crystals grown by chemical vapor transport. The ratio of the intensities of the Raman peak from the Si substrate and the E2g peak of TaSe2 presents a convenient metric for quantifying film thickness. The temperature coefficients for two main Raman peaks, A1g and E2g, are -0.013 and -0.0097 cm-1/oC, respectively. The Raman optothermal measurements indicate that the room temperature thermal conductivity in these films decreases from its bulk value of ˜16 W/mK to ˜9 W/mK in 45-nm thick films. The measurement of electrical resistivity of the field-effect devices with TaSe2 channels shows that heat conduction is dominated by acoustic phonons in these van der Waals films. The scaling of thermal conductivity with the film thickness suggests that the phonon scattering from the film boundaries is substantial despite the sharp interfaces of the mechanically cleaved samples. These results are important for understanding the thermal properties of thin films exfoliated from TaSe2 and other metal dichalcogenides, as well as for evaluating self-heating effects in devices made from such materials.

  12. 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.

  13. Pyroelectric response of lead zirconate titanate thin films on silicon: Effect of thermal stresses

    Energy Technology Data Exchange (ETDEWEB)

    Kesim, M. T.; Zhang, J.; Alpay, S. P. [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Trolier-McKinstry, S. [Department of Materials Science and Engineering and Materials Research Institute, Pennsylvania State University, Pennsylvania 16802 (United States); Mantese, J. V. [United Technologies Research Center, East Hartford, Connecticut 06118 (United States); Whatmore, R. W. [Tyndall National Institute, Lee Maltings, Dyke Parade, Cork City, County Cork (Ireland)

    2013-11-28

    Ferroelectric lead zirconate titanate [Pb(Zr{sub x}Ti{sub 1-x}O){sub 3}, (PZT x:1-x)] has received considerable interest for applications related to uncooled infrared devices due to its large pyroelectric figures of merit near room temperature, and the fact that such devices are inherently ac coupled, allowing for simplified image post processing. For ferroelectric films made by industry-standard deposition techniques, stresses develop in the PZT layer upon cooling from the processing/growth temperature due to thermal mismatch between the film and the substrate. In this study, we use a non-linear thermodynamic model to investigate the pyroelectric properties of polycrystalline PZT thin films for five different compositions (PZT 40:60, PZT 30:70, PZT 20:80, PZT 10:90, PZT 0:100) on silicon as a function of processing temperature (25–800 °C). It is shown that the in-plane thermal stresses in PZT thin films alter the out-of-plane polarization and the ferroelectric phase transformation temperature, with profound effect on the pyroelectric properties. PZT 30:70 is found to have the largest pyroelectric coefficient (0.042 μC cm{sup −2} °C{sup −1}, comparable to bulk values) at a growth temperature of 550 °C; typical to what is currently used for many deposition processes. Our results indicate that it is possible to optimize the pyroelectric response of PZT thin films by adjusting the Ti composition and the processing temperature, thereby, enabling the tailoring of material properties for optimization relative to a specific deposition process.

  14. Thermal Cycling Behavior of Zinc Antimonide Thin Films for High Temperature Thermoelectric Power Generation Applications.

    Science.gov (United States)

    Shim, Hyung Cheoul; Woo, Chang-Su; Han, Seungwoo

    2015-08-19

    The zinc antimonide compound ZnxSby is one of the most efficient thermoelectric materials known at high temperatures due to its exceptional low thermal conductivity. For this reason, it continues to be the focus of active research, especially regarding its glass-like atomic structure. However, before practical use in actual surroundings, such as near a vehicle manifold, it is imperative to analyze the thermal reliability of these materials. Herein, we present the thermal cycling behavior of ZnxSby thin films in nitrogen (N2) purged or ambient atmosphere. ZnxSby thin films were prepared by cosputtering and reached a power factor of 1.39 mW m(-1) K(-2) at 321 °C. We found maximum power factor values gradually decreased in N2 atmosphere due to increasing resistivity with repeated cycling, whereas the specimen in air kept its performance. X-ray diffraction and electron microscopy observations revealed that fluidity of Zn atoms leads to nanoprecipitates, porous morphologies, and even growth of a coating layer or fiber structures on the surface of ZnxSby after repetitive heating and cooling cycles. With this in mind, our results indicate that proper encapsulation of the ZnxSby surface would reduce these unwanted side reactions and the resulting degradation of thermoelectric performance.

  15. DLC and AlN thin films influence the thermal conduction of HPLED light

    Science.gov (United States)

    Hsu, Ming Seng; Hsu, Ching Yao; Huang, Jen Wei; Shyu, Feng Lin

    2015-08-01

    Thermal dissipation had an important influence in the effect and life of light emitting diodes (LED) because it enables transfer the heat away from electric device to the aluminum plate that can be used for heat removal. In the industrial processing, the quality of the thermal dissipation decides by the gumming technique between the PCB and aluminum plate. In this study, we fabricated double layer ceramic thin films of diamond like carbon (DLC) and alumina nitride (AlN) by vacuum sputtering soldered the substrate of high power light emitting diodes (HPLED) light to check the heat conduction. The ceramic dielectric coatings were characterized by several subsequent analyses, especially the measurement of real work temperature. The X-Ray photoelectron spectroscopy (XPS) patterns reveal those ceramic phases were successfully grown onto the substrate. The work temperatures show DLC and AlN films coating had limited the heat transfer by the lower thermal conductivity of these ceramic films. Obviously, it hadn't transferred heat and limited work temperature of HPLED better than DLC thin film only.

  16. Origin of thermally stable ferroelectricity in a porous barium titanate thin film synthesized through block copolymer templating

    Directory of Open Access Journals (Sweden)

    Norihiro Suzuki

    2017-07-01

    Full Text Available A porous barium titanate (BaTiO3 thin film was chemically synthesized using a surfactant-assisted sol-gel method in which micelles of amphipathic diblock copolymers served as structure-directing agents. In the Raman spectrum of the porous BaTiO3 thin film, a peak corresponding to the ferroelectric tetragonal phase was observed at around 710 cm−1, and it remained stable at much higher temperature than the Curie temperature of bulk single-crystal BaTiO3 (∼130 °C. Measurements revealed that the ferroelectricity of the BaTiO3 thin film has high thermal stability. By analyzing high-resolution transmission electron microscope images of the BaTiO3 thin film by the fast Fourier transform mapping method, the spatial distribution of stress in the BaTiO3 framework was clearly visualized. Careful analysis also indicated that the porosity in the BaTiO3 thin film introduced anisotropic compressive stress, which deformed the crystals. The resulting elongated unit cell caused further displacement of the Ti4+ cation from the center of the lattice. This displacement increased the electric dipole moment of the BaTiO3 thin film, effectively enhancing its ferro(piezoelectricity.

  17. Thermally tunable VO2-SiO2 nanocomposite thin-film capacitors

    Science.gov (United States)

    Sun, Yifei; Narayanachari, K. V. L. V.; Wan, Chenghao; Sun, Xing; Wang, Haiyan; Cooley, Kayla A.; Mohney, Suzanne E.; White, Doug; Duwel, Amy; Kats, Mikhail A.; Ramanathan, Shriram

    2018-03-01

    We present a study of co-sputtered VO2-SiO2 nanocomposite dielectric thin-film media possessing continuous temperature tunability of the dielectric constant. The smooth thermal tunability is a result of the insulator-metal transition in the VO2 inclusions dispersed within an insulating matrix. We present a detailed comparison of the dielectric characteristics of this nanocomposite with those of a VO2 control layer and of VO2/SiO2 laminate multilayers of comparable overall thickness. We demonstrated a nanocomposite capacitor that has a thermal capacitance tunability of ˜60% between 25 °C and 100 °C at 1 MHz, with low leakage current. Such thermally tunable capacitors could find potential use in applications such as sensing, thermal cloaks, and phase-change energy storage devices.

  18. Thermal pulse measurements of space charge distributions under an applied electric field in thin films

    International Nuclear Information System (INIS)

    Zheng, Feihu; An, Zhenlian; Zhang, Yewen; Liu, Chuandong; Lin, Chen; Lei, Qingquan

    2013-01-01

    The thermal pulse method is a powerful method to measure space charge and polarization distributions in thin dielectric films, but a complicated calibration procedure is necessary to obtain the real distribution. In addition, charge dynamic behaviour under an applied electric field cannot be observed by the classical thermal pulse method. In this work, an improved thermal pulse measuring system with a supplemental circuit for applying high voltage is proposed to realize the mapping of charge distribution in thin dielectric films under an applied field. The influence of the modified measuring system on the amplitude and phase of the thermal pulse response current are evaluated. Based on the new measuring system, an easy calibration approach is presented with some practical examples. The newly developed system can observe space charge evolution under an applied field, which would be very helpful in understanding space charge behaviour in thin films. (paper)

  19. Tungsten oxide thin films grown by thermal evaporation with high resistance to leaching

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Diogo S. [Universidade Federal de Pelotas (UFPel), RS (Brazil). Centro de Ciencias Quimicas, Farmaceuticas e de Alimentos; Pazinato, Julia C.O.; Freitas, Mauricio A. de; Radtke, Claudio; Garcia, Irene T.S., E-mail: irene@iq.ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Instituto de Quimica; Dorneles, Lucio S. [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Centro de Ciencias Naturais e Exatas

    2014-05-15

    Tungsten oxides show different stoichiometries, crystal lattices and morphologies. These characteristics are important mainly when they are used as photocatalysts. In this work tungsten oxide thin films were obtained by thermal evaporation on (100) silicon substrates covered with gold and heated at 350 and 600 °C, with different deposition times. The stoichiometry of the films, morphology, crystal structure and resistance to leaching were characterized through X-ray photoelectron spectroscopy, micro-Raman spectroscopy, scanning and transmission electron microscopy, X-ray diffractometry, Rutherford backscattering spectrometry and O{sup 16} (α,α')O{sup 16} resonant nuclear reaction. Films obtained at higher temperatures show well-defined spherical nanometric structure; they are composed of WO{sub 3.1} and the presence of hydrated tungsten oxide was also observed. The major crystal structure observed is the hexagonal. Thin films obtained through thermal evaporation present resistance to leaching in aqueous media and excellent performance as photocatalysts, evaluated through the degradation of the methyl orange dye. (author)

  20. Thermally evaporated thin films of SnS for application in solar cell devices

    International Nuclear Information System (INIS)

    Miles, Robert W.; Ogah, Ogah E.; Zoppi, Guillaume; Forbes, Ian

    2009-01-01

    SnS (tin sulphide) is of interest for use as an absorber layer and the wider energy bandgap phases e.g. SnS 2 , Sn 2 S 3 and Sn/S/O alloys of interest as Cd-free buffer layers for use in thin film solar cells. In this work thin films of tin sulphide have been thermally evaporated onto glass and SnO 2 :coated glass substrates with the aim of optimising the properties of the material for use in photovoltaic solar cell device structures. In particular the effects of source temperature, substrate temperature, deposition rate and film thickness on the chemical and physical properties of the layers were investigated. Energy dispersive X-ray analysis was used to determine the film composition, X-ray diffraction to determine the phases present and structure of each phase, transmittance and reflectance versus wavelength measurements to determine the energy bandgap and scanning electron microscopy to observe the surface topology and topography and the properties correlated to the deposition parameters. Using the optimised conditions it is possible to produce thin films of tin sulphide that are pinhole free, conformal to the substrate and that consist of densely packed columnar grains. The composition, phases present and the optical properties of the layers deposited were found to be highly sensitive to the deposition conditions. Energy bandgaps in the range 1.55 eV-1.7 eV were obtained for a film thickness of 0.8 μm, and increasing the film thickness to > 1 μm resulted in a reduction of the energy bandgap to less than 1.55 eV. The applicability of using these films in photovoltaic solar cell device structures is also discussed.

  1. Alternative nano-structured thin-film materials used as durable thermal nanoimprint lithography templates

    Science.gov (United States)

    Bossard, M.; Boussey, J.; Le Drogoff, B.; Chaker, M.

    2016-02-01

    Nanoimprint templates made of diamond-like carbon (DLC) and amorphous silicon carbide (SiC) thin films and fluorine-doped associated materials, i.e. F-DLC and F-SiC were investigated in the context of thermal nanoimprint lithography (NIL) with respect to their release properties. Their performances in terms of durability and stability were evaluated and compared to those of conventional silicon or silica molds coated with antisticking molecules applied as a self-assembled monolayer. Plasma-enhanced chemical vapor deposition parameters were firstly tuned to optimize mechanical and structural properties of the DLC and SiC thin films. The impact of the amount of fluorine dopant on the deposited thin films properties was then analyzed. A comparative analysis of DLC, F-DLC as well as SiC and F-SiC molds was then carried out over multiple imprints, performed into poly (methyl methacrylate) (PMMA) thermo-plastic resist. The release properties of un-patterned films were evaluated by the measurement of demolding energies and surface energies, associated with a systematic analysis of the mold surface contamination. These analyses showed that the developed materials behave as intrinsically easy-demolding and contamination-free molds over series of up to 40 imprints. To our knowledge, it is the first time that such a large number of imprints has been considered within an exhaustive comparative study of materials for NIL. Finally, the developed materials went through standard e-beam lithography and plasma etching processes to obtain nanoscale-patterned templates. The replicas of those patterned molds, imprinted into PMMA, were shown to be of high fidelity and good stability after several imprints.

  2. Alternative nano-structured thin-film materials used as durable thermal nanoimprint lithography templates

    International Nuclear Information System (INIS)

    Bossard, M; Boussey, J; Le Drogoff, B; Chaker, M

    2016-01-01

    Nanoimprint templates made of diamond-like carbon (DLC) and amorphous silicon carbide (SiC) thin films and fluorine-doped associated materials, i.e. F–DLC and F–SiC were investigated in the context of thermal nanoimprint lithography (NIL) with respect to their release properties. Their performances in terms of durability and stability were evaluated and compared to those of conventional silicon or silica molds coated with antisticking molecules applied as a self-assembled monolayer. Plasma-enhanced chemical vapor deposition parameters were firstly tuned to optimize mechanical and structural properties of the DLC and SiC thin films. The impact of the amount of fluorine dopant on the deposited thin films properties was then analyzed. A comparative analysis of DLC, F–DLC as well as SiC and F–SiC molds was then carried out over multiple imprints, performed into poly (methyl methacrylate) (PMMA) thermo-plastic resist. The release properties of un-patterned films were evaluated by the measurement of demolding energies and surface energies, associated with a systematic analysis of the mold surface contamination. These analyses showed that the developed materials behave as intrinsically easy-demolding and contamination-free molds over series of up to 40 imprints. To our knowledge, it is the first time that such a large number of imprints has been considered within an exhaustive comparative study of materials for NIL. Finally, the developed materials went through standard e-beam lithography and plasma etching processes to obtain nanoscale-patterned templates. The replicas of those patterned molds, imprinted into PMMA, were shown to be of high fidelity and good stability after several imprints. (paper)

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

    Science.gov (United States)

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

    2016-12-01

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

  4. Effect of substrate properties and thermal annealing on the resistivity of molybdenum thin films

    International Nuclear Information System (INIS)

    Schmid, U.; Seidel, H.

    2005-01-01

    In this study, the influence of substrate properties (e.g. roughness characteristics and chemical composition) on the electrical resistivity of evaporated molybdenum thin films is investigated as a function of varying parameters, such as film thickness (25-115 nm) and post-deposition annealing with temperatures up to T PDA = 900 deg. C. A thermally oxidized silicon wafer with very low surface roughness was used as one substrate type. In contrast, a low temperature co-fired ceramics substrate with a glass encapsulant printed in thick film technology is the representative for rough surface morphology. The electrical resistivity follows the prediction of the size effect up to T PDA = 600 deg. C independent of substrate nature. On the silicon-based substrate, the thickness-independent portion of the film resistivity ρ g in the 'as deposited' state is about 29 times higher than the corresponding bulk value for a mono-crystalline sample. Thin films of this refractory metal on the SiO 2 /Si substrate exhibit an average grain size of 4.9 nm and a negative temperature coefficient of resistivity (TCR). On the glass/ceramic-based substrate, however, ρ g is half the value as compared to that obtained on the SiO 2 /Si substrate and the TCR is positive

  5. Thermal Molding of Organic Thin-Film Transistor Arrays on Curved Surfaces.

    Science.gov (United States)

    Sakai, Masatoshi; Watanabe, Kento; Ishimine, Hiroto; Okada, Yugo; Yamauchi, Hiroshi; Sadamitsu, Yuichi; Kudo, Kazuhiro

    2017-12-01

    In this work, a thermal molding technique is proposed for the fabrication of plastic electronics on curved surfaces, enabling the preparation of plastic films with freely designed shapes. The induced strain distribution observed in poly(ethylene naphthalate) films when planar sheets were deformed into hemispherical surfaces clearly indicated that natural thermal contraction played an important role in the formation of the curved surface. A fingertip-shaped organic thin-film transistor array molded from a real human finger was fabricated, and slight deformation induced by touching an object was detected from the drain current response. This type of device will lead to the development of robot fingers equipped with a sensitive tactile sense for precision work such as palpation or surgery.

  6. Conductivity enhancement of multiwalled carbon nanotube thin film via thermal compression method

    Science.gov (United States)

    Tsai, Wan-Lin; Wang, Kuang-Yu; Chang, Yao-Jen; Li, Yu-Ren; Yang, Po-Yu; Chen, Kuan-Neng; Cheng, Huang-Chung

    2014-08-01

    For the first time, the thermal compression method is applied to effectively enhance the electrical conductivity of carbon nanotube thin films (CNTFs). With the assistance of heat and pressure on the CNTFs, the neighbor multiwalled carbon nanotubes (CNTs) start to link with each other, and then these separated CNTs are twined into a continuous film while the compression force, duration, and temperature are quite enough for the reaction. Under the compression temperature of 400°C and the compression force of 100 N for 50 min, the sheet resistance can be reduced from 17 to 0.9 k Ω/sq for the CNTFs with a thickness of 230 nm. Moreover, the effects of compression temperature and the duration of thermal compression on the conductivity of CNTF are also discussed in this work.

  7. Improved electrical stability of CdS thin film transistors through Hydrogen-based thermal treatments

    KAUST Repository

    Salas Villaseñor, Ana L.

    2014-06-01

    Thin film transistors (TFTs) with a bottom-gate configuration were fabricated using a photolithography process with chemically bath deposited (CBD) cadmium sulfide (CdS) films as the active channel. Thermal annealing in hydrogen was used to improve electrical stability and performance of the resulting CdS TFTs. Hydrogen thermal treatments results in significant V T instability (V T shift) improvement while increasing the I on/I off ratio without degrading carrier mobility. It is demonstrated that after annealing V T shift and I on/I off improves from 10 V to 4.6 V and from 105 to 10 9, respectively. Carrier mobility remains in the order of 14.5 cm2 V s-1. The reduced V T shift and performance is attributed to a reduction in oxygen species in the CdS after hydrogen annealing, as evaluated by Fourier transform infrared spectroscopy (FTIR). © 2014 IOP Publishing Ltd.

  8. Thermal Molding of Organic Thin-Film Transistor Arrays on Curved Surfaces

    Science.gov (United States)

    Sakai, Masatoshi; Watanabe, Kento; Ishimine, Hiroto; Okada, Yugo; Yamauchi, Hiroshi; Sadamitsu, Yuichi; Kudo, Kazuhiro

    2017-05-01

    In this work, a thermal molding technique is proposed for the fabrication of plastic electronics on curved surfaces, enabling the preparation of plastic films with freely designed shapes. The induced strain distribution observed in poly(ethylene naphthalate) films when planar sheets were deformed into hemispherical surfaces clearly indicated that natural thermal contraction played an important role in the formation of the curved surface. A fingertip-shaped organic thin-film transistor array molded from a real human finger was fabricated, and slight deformation induced by touching an object was detected from the drain current response. This type of device will lead to the development of robot fingers equipped with a sensitive tactile sense for precision work such as palpation or surgery.

  9. Thermal resistances of crystalline and amorphous few-layer oxide thin films

    Directory of Open Access Journals (Sweden)

    Liang Chen

    2017-11-01

    Full Text Available Thermal insulation at nanoscale is of crucial importance for non-volatile memory devices such as phase change memory and memristors. We perform non-equilibrium molecular dynamics simulations to study the effects of interface materials and structures on thermal transport across the few-layer dielectric nanostructures. The thermal resistance across few-layer nanostructures and thermal boundary resistance at interfaces consisting of SiO2/HfO2, SiO2/ZrO2 or SiO2/Al2O3 are obtained for both the crystalline and amorphous structures. Based on the comparison temperature profiles and phonon density of states, we show that the thermal boundary resistances are much larger in crystalline few-layer oxides than the amorphous ones due to the mismatch of phonon density of state between distinct oxide layers. Compared with the bulk SiO2, the increase of thermal resistance across crystalline few-layer oxides results from the thermal boundary resistance while the increase of thermal resistance across amorphous few-layer oxides is attributed to the lower thermal conductivity of the amorphous thin films.

  10. Doping-tunable thermal emission from plasmon polaritons in semiconductor epsilon-near-zero thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Young Chul [Inha Univ., Incheon (Korea, Republic of). Dept. of Physics; Luk, Ting S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Integrated Nanotechnologies; Robert Ellis, A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Klem, John F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brener, Igal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Integrated Nanotechnologies

    2014-09-29

    Here, we utilize the unique dispersion properties of leaky plasmon polaritons in epsilon-near-zero (ENZ) thin films to demonstrate thermal radiation control. Owing to its highly flat dispersion above the light line, a thermally excited leaky wave at the ENZ frequency out-couples into free space without any scattering structures, resulting in a narrowband, wide-angle, p-polarized thermal emission spectrum. We demonstrate this idea by measuring angle- and polarization-resolved thermal emission spectra from a single layer of unpatterned, doped semiconductors with deep-subwavelength film thickness (d/λ0 ~ 6 ×10-3, where d is the film thickness and λ0 is the free space wavelength). We show that this semiconductor ENZ film effectively works as a leaky wave thermal radiation antenna, which generates far-field radiation from a thermally excited mode. The use of semiconductors makes the radiation frequency highly tunable by controlling doping densities and also facilitates device integration with other components. Therefore, this leaky plasmon polariton emission from semiconductor ENZ films provides an avenue for on-chip control of thermal radiation.

  11. Preparation of SnS thin films with gear-like sheet appearance by close-spaced vacuum thermal evaporation

    Science.gov (United States)

    Shao, Zhangpeng; Shi, Chengwu; Chen, Junjun; Zhang, Yanru

    2017-07-01

    SnS thin films with gear-like sheet appearance were successfully prepared by close-spaced vacuum thermal evaporation using SnS powders as a source. The influence of substrate temperature on the surface morphology, chemical composition, crystal structure and optical property of SnS thin films was investigated by scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction and ultraviolet-visible-near infrared spectroscopy. The results revealed that serration architecture appeared obviously in the edge of the SnS sheet and the strongest peak at 2𝜃=31.63∘ was broadened and many shoulder peaks were observed with increasing substrate temperature. The atomic ratio of Sn to S increased from 1:1.08 to 1:1.20, the grain size became slightly smaller and the optical absorption edge had a blueshift in the SnS thin film with decreasing substrate temperature.

  12. Design and fabrication of thin film Bi-Sb and Bi-Cu thermopiles for IR thermal radiation detection

    CERN Document Server

    Afzalzadeh, R

    2003-01-01

    Thin film thermopiles are widely used as small size sensors, in particular to sense infra-red thermal radiations. In this paper a method for designing and fabrication of thin films Bi-Cu thermopiles in linear in linear array of 8 and 11 elements in series and mono-layer is introduced. Also, fabrication of of Bi-Cu thin film thermopiles, which are used as IR radiation sensors, made in multilayer from with 100 series junctions in circular shape are presented. The samples are fabricated on a PCB board with double-side copper laminated as a substrate. The results of our measurements show that the output voltage produced due to temperature difference between junctions, is very sensitive and linear to temperature difference.

  13. Thermal and Electrical Effects of Partial Shade in Monolithic Thin-Film Photovoltaic Modules: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Silverman, Timothy J.; Deceglie, Michael G.; Sun, Xingshu; Garris, Rebekah L.; Alam, Muhammad Ashraful; Deline, Chris; Kurtz, Sarah

    2015-09-02

    Photovoltaic cells can be damaged by reverse bias stress, which arises during service when a monolithically integrated thin-film module is partially shaded. We introduce a model for describing a module's internal thermal and electrical state, which cannot normally be measured. Using this model and experimental measurements, we present several results with relevance for reliability testing and module engineering: Modules with a small breakdown voltage experience less stress than those with a large breakdown voltage, with some exceptions for modules having light-enhanced reverse breakdown. Masks leaving a small part of the masked cells illuminated can lead to very high temperature and current density compared to masks covering entire cells.

  14. The anomalous low temperature resistivity of thermally evaporated α-Mn thin film

    International Nuclear Information System (INIS)

    Ampong, F.K.; Boakye, F.; Nkum, R.K.

    2010-01-01

    Electrical resistivity measurements have been carried out on thermally evaporated α-Mn thin film between 300 and 1.4 K using the van der Pauw four probe technique. The film was grown on a glass substrate held at a temperature of 373 K, in an ambient pressure of 5x10 -6 Torr. The results show a resistance minimum, a notable characteristic of α-Mn but at a (rather high) temperature of 194±1 K. Below the resistivity maximum which corresponds to 70 K, the resistivity drops by only 0.02 μΩm indicating a rather short range magnetic ordering. The low temperature results show a tendency towards saturation of the resistivity as the temperature approaches zero suggesting a Kondo scattering.

  15. The anomalous low temperature resistivity of thermally evaporated alpha-Mn thin film

    Energy Technology Data Exchange (ETDEWEB)

    Ampong, F.K., E-mail: kampxx@yahoo.co [Department of Physics, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana); Boakye, F.; Nkum, R.K. [Department of Physics, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana)

    2010-08-15

    Electrical resistivity measurements have been carried out on thermally evaporated alpha-Mn thin film between 300 and 1.4 K using the van der Pauw four probe technique. The film was grown on a glass substrate held at a temperature of 373 K, in an ambient pressure of 5x10{sup -6} Torr. The results show a resistance minimum, a notable characteristic of alpha-Mn but at a (rather high) temperature of 194+-1 K. Below the resistivity maximum which corresponds to 70 K, the resistivity drops by only 0.02 muOMEGAm indicating a rather short range magnetic ordering. The low temperature results show a tendency towards saturation of the resistivity as the temperature approaches zero suggesting a Kondo scattering.

  16. Experimental Investigation of Zinc Antimonide Thin Films under Different Thermal Boundary Conditions

    DEFF Research Database (Denmark)

    Mir Hosseini, Seyed Mojtaba; Rosendahl, Lasse Aistrup; Rezaniakolaei, Alireza

    Zinc antimonide compound ZnxSby is one of the most efficient thermoelectric (TE) materials known at high temperatures regarding to its exceptional low thermal conductivity. For this reason, it continues to be the focus of active research. However, before practical use in actual conditions......, it is imperative to analyze the thermo electrical behavior of these materials. In this study, the results are considered for different hot side temperature of the film in steady state condition. Six temperatures at hot side of the specimen are provided; 150, 200, 250, 300, 350, and 400 ᵒC. At the beginning of each...... for all cases, showing that the electrical potential difference is increasing by temperature for all cases with the same slope. Also the value of Seebeck coefficient (α) is almost constant for all cases. The obtained value of α can compete with developed bulk TEG materials in literature. The thin film...

  17. Magnetic field and temperature dependent measurements of hall coefficient in thermal evaporated Tin-Doped Cadmium Oxide Thin films

    International Nuclear Information System (INIS)

    Hamadi, O.; Shakir, N.; Mohammed, F.

    2010-01-01

    CdO:Sn thin films are deposited onto glass substrates by thermal evaporation under vacuum. The studied films are polycrystalline and have an NaCl structure. The Hall effect is studied for films with different thickness as substrates are maintained at different temperatures. The temperature dependence of the Hall mobility is also investigated. (authors)

  18. Growth and thermal oxidation of Ru and ZrO2 thin films as oxidation protective layers

    NARCIS (Netherlands)

    Coloma Ribera, R.

    2017-01-01

    This thesis focuses on the study of physical and chemical processes occurring during growth and thermal oxidation of Ru and ZrO2 thin films. Acting as oxidation resistant capping materials to prevent oxidation of layers underneath, these films have several applications, i.e., in microelectronics

  19. Development of Ultrafast Laser Flash Methods for Measuring Thermophysical Properties of Thin Films and Boundary Thermal Resistances

    Science.gov (United States)

    Baba, Tetsuya; Taketoshi, Naoyuki; Yagi, Takashi

    2011-11-01

    Reliable thermophysical property values of thin films are important to develop advanced industrial technologies such as highly integrated electronic devices, phase-change memories, magneto-optical disks, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), semiconductor lasers (LDs), flat-panel displays, and power electronic devices. In order to meet these requirements, the National Metrology Institute of Japan of the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) has developed ultrafast laser flash methods heated by picosecond pulse or nanosecond pulse with the same geometrical configuration as the laser flash method, which is the standard method to measure the thermal diffusivity of bulk materials. Since these pulsed light heating methods induce one-dimensional heat diffusion across a well-defined length of the specimen thickness, the absolute value of thermal diffusivity across thin films can be measured reliably. Using these ultrafast laser flash methods, the thermal diffusivity of each layer of multilayered thin films and the boundary thermal resistance between the layers can be determined from the observed transient temperature curves based on the response function method. The thermophysical properties of various thin films important for modern industries such as the transparent conductive films used for flat-panel displays, hard coating films, and multilayered films of next-generation phase-change optical disks have been measured by these methods.

  20. Structural and optical properties of Zn–In–Te thin films deposited by thermal evaporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Güllü, H.H.; Bayraklı, Ö.; Candan, İ. [Department of Physics, Middle East Technical University, GUNAM, 06800 Ankara (Turkey); Coşkun, E. [Department of Physics, Middle East Technical University, GUNAM, 06800 Ankara (Turkey); Department of Physics, Çanakkale Onsekiz Mart University, 17100 Çanakkale (Turkey); Parlak, M., E-mail: parlak@metu.edu.tr [Department of Physics, Middle East Technical University, GUNAM, 06800 Ankara (Turkey)

    2013-07-25

    Highlights: •The new ternary compound Zn–In–Te (ZIT) has been studied for photovoltaic device applications as an absorber layer. •ZIT thin films were deposited by thermal evaporation of stoichiometric sintered polycrystalline powder. •The optical constants were calculated by using different methods, (SOM), Envelope Model (EM) and Cauchy Method. •Urbach energies were calculated and the increasing band tail energies were observed with increasing annealing temperature. -- Abstract: Annealing effects on structural and optical properties of the thermally evaporated Zn–In–Te (ZIT) thin films have been investigated. The structural and the compositional analyses were carried out by means of X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDXA). The as-grown and annealed ZIT films had polycrystalline structure and the preferred orientation changed from (2 2 0) to (1 1 2) direction with increasing annealing temperature. The optical properties and constants were determined by transmittance measurements in the wavelength range of 200–2000 nm. The effect of annealing on the optical parameters was determined by using Single Oscillator Model (SOM), Envelope Model (EM) and Cauchy Method. The absorbance studies revealed that the films had three distinct transitions in the high absorption region because of the tetragonal distortion, and that was used to evaluate the splitting energies of crystal-field and spin–orbit splitting. The fundamental optical band gap values were found to be lying in the range of 1.51 and 1.72 eV and the notable change of the band gaps due to annealing temperatures was observed. Finally, the Urbach energies were calculated and it was observed that the band tail energies were increasing with increasing annealing temperature.

  1. Thermal treatment influence on the preparation of BPSCCO superconductor thin films

    Energy Technology Data Exchange (ETDEWEB)

    Torsoni, Guilherme Botega; Carvalho, Claudio Luiz [UNESP, Ilha Solteira, SP (Brazil). Dept. de Fisica e Quimica

    2011-07-01

    Full text: Nowadays, with the evolution of technology, superconducting thin films application in microelectronics is essential for production of some equipment with reduced size and low energy consumption. There are different ways to prepare thin films, however deposition in liquid phase have received special attention, whose main features are: fast deposition, reduced cost and the possibility of covering large areas. Basically, the method consists to deposit a polymeric precursor solution, with synthesis based on the methodology developed by M. Pechini, on a crystalline substrate using a spin coating equipment also called spinner. In the deposition process by spinner, must be considered some physical parameters, such as, rotation speed, viscosity solution, substrate acceleration and rotating time, evaporation rate and temperature solution. Immediately after the deposition, the material is submitted to different thermal treatments, this consists of two stages, in other words, calcination and sintering stages. The objective of the first stage is to remove the organic compounds, which can be done at temperatures around 500 deg C - 600 deg C, and the other stage, it can be done around 750 deg C and 850 deg C, it means the same interval of phase formation. In this work, films were made with five layers of deposition on Si substrate in three different sintering temperatures, 750, 800 and 850 deg C and it was studied the evolution of the films due to thermal treatment applied. Characterizations were made by x-ray diffraction, microscopy by field emission gun and energy dispersive x-ray (EDS). X-ray diffractograms shown that 2212 phase was obtained in all samples submitted to different temperatures, for higher sintering temperature was not observed any kind of crystalline planes orientation and the electron microscopy and EDS showed that the films are also more homogeneous. (author)

  2. Thermal treatment influence on the preparation of BPSCCO superconductor thin films

    International Nuclear Information System (INIS)

    Torsoni, Guilherme Botega; Carvalho, Claudio Luiz

    2011-01-01

    Full text: Nowadays, with the evolution of technology, superconducting thin films application in microelectronics is essential for production of some equipment with reduced size and low energy consumption. There are different ways to prepare thin films, however deposition in liquid phase have received special attention, whose main features are: fast deposition, reduced cost and the possibility of covering large areas. Basically, the method consists to deposit a polymeric precursor solution, with synthesis based on the methodology developed by M. Pechini, on a crystalline substrate using a spin coating equipment also called spinner. In the deposition process by spinner, must be considered some physical parameters, such as, rotation speed, viscosity solution, substrate acceleration and rotating time, evaporation rate and temperature solution. Immediately after the deposition, the material is submitted to different thermal treatments, this consists of two stages, in other words, calcination and sintering stages. The objective of the first stage is to remove the organic compounds, which can be done at temperatures around 500 deg C - 600 deg C, and the other stage, it can be done around 750 deg C and 850 deg C, it means the same interval of phase formation. In this work, films were made with five layers of deposition on Si substrate in three different sintering temperatures, 750, 800 and 850 deg C and it was studied the evolution of the films due to thermal treatment applied. Characterizations were made by x-ray diffraction, microscopy by field emission gun and energy dispersive x-ray (EDS). X-ray diffractograms shown that 2212 phase was obtained in all samples submitted to different temperatures, for higher sintering temperature was not observed any kind of crystalline planes orientation and the electron microscopy and EDS showed that the films are also more homogeneous. (author)

  3. Influence of Thermal Treatments on In-depth Compositional Uniformity of CuIn(S,Se)2 Thin Films

    Science.gov (United States)

    Xie, Hai-bing; Liu, Wei-feng; Jiang, Guo-shun; Li, Xin-yi; Yan, Fei; Zhu, Chang-fei

    2012-08-01

    CuIn(S,Se)2 thin films were prepared by thermal crystallization of co-sputtered Cu-In alloy precursors in S/Se atmosphere. In-depth compositional uniformity is an important prerequisite for obtaining device-quality CuIn(S,Se)2 absorber thin films. In order to figure out the influence of heat treatments on in-depth composition uniformity of CuIn(S,Se)2 thin films, two kinds of reaction temperature profiles were investigated. One process is “one step profile", referring to formation of CuIn(S,Se)2 thin films just at elevated temperature (e.g. 500 °C). The other is “two step profile", which allows for slow diffusion of S and Se elements into the alloy precursors at a low temperature before the formation and re-crystallization of CuIn(S,Se)2 thin films at higher temperature (e.g. first 250 °C then 500 °C). X-ray diffraction studies reveal that there is a discrepancy in the shape of (112) peak. Samples annealed with “one step profile" have splits on (112) peaks, while samples annealed with “two step profile" have relatively symmetrical (112) peaks. Grazing incident X-ray diffraction and energy dispersive spectrum measurements of samples successively etched in bromine methanol show that CuIn(S,Se)2 thin films have better in-depth composition uniformity after “two step profile" annealing. The reaction mechanism during the two thermal processing was also investigated by X-ray diffraction and Raman spectra.

  4. Thin film device applications

    CERN Document Server

    Kaur, Inderjeet

    1983-01-01

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

  5. Large Enhancement of Thermal Conductivity and Lorenz Number in Topological Insulator Thin Films.

    Science.gov (United States)

    Luo, Zhe; Tian, Jifa; Huang, Shouyuan; Srinivasan, Mithun; Maassen, Jesse; Chen, Yong P; Xu, Xianfan

    2018-02-27

    Topological insulators (TI) have attracted extensive research effort due to their insulating bulk states but conducting surface states. However, investigation and understanding of thermal transport in topological insulators, particularly the effect of surface states, are lacking. In this work, we studied thickness-dependent in-plane thermal and electrical conductivity of Bi 2 Te 2 Se TI thin films. A large enhancement in both thermal and electrical conductivity was observed for films with thicknesses below 20 nm, which is attributed to the surface states and bulk-insulating nature of these films. Moreover, a surface Lorenz number much larger than the Sommerfeld value was found. Systematic transport measurements indicated that the Fermi surface is located near the charge neutrality point (CNP) when the film thickness is below 20 nm. Possible reasons for the large Lorenz number include electrical and thermal current decoupling in the surface state Dirac fluid, and bipolar diffusion transport. A simple computational model indicates that the surface states and bipolar diffusion indeed can lead to enhanced electrical and thermal transport and a large Lorenz number.

  6. Fast Adaptive Thermal Camouflage Based on Flexible VO₂/Graphene/CNT Thin Films.

    Science.gov (United States)

    Xiao, Lin; Ma, He; Liu, Junku; Zhao, Wei; Jia, Yi; Zhao, Qiang; Liu, Kai; Wu, Yang; Wei, Yang; Fan, Shoushan; Jiang, Kaili

    2015-12-09

    Adaptive camouflage in thermal imaging, a form of cloaking technology capable of blending naturally into the surrounding environment, has been a great challenge in the past decades. Emissivity engineering for thermal camouflage is regarded as a more promising way compared to merely temperature controlling that has to dissipate a large amount of excessive heat. However, practical devices with an active modulation of emissivity have yet to be well explored. In this letter we demonstrate an active cloaking device capable of efficient thermal radiance control, which consists of a vanadium dioxide (VO2) layer, with a negative differential thermal emissivity, coated on a graphene/carbon nanotube (CNT) thin film. A slight joule heating drastically changes the emissivity of the device, achieving rapid switchable thermal camouflage with a low power consumption and excellent reliability. It is believed that this device will find wide applications not only in artificial systems for infrared camouflage or cloaking but also in energy-saving smart windows and thermo-optical modulators.

  7. Preparation and Investigation of the Thermal Stability of Phosphate-modified TiO2 Anatase Powders and Thin Films.

    Science.gov (United States)

    Prah, Uroš; Škofic, Irena Kozjek

    2017-12-01

    The temperature dependence of the anatase-to-rutile phase transition of TiO2 powders and thin films was studied. In order to shift the phase transition to higher temperature, samples were doped with a different amount of phosphate ions and their influence on the structure and thermal stability of the anatase phase was investigated. In addition, the effect of the catalyst form (powders or thin films) on the temperature of the anatase-to-rutile phase transition was observed. TiO2 thin films and powders were prepared using a simple sol-gel method with an alkoxide precursor and citric acid. The thin films were deposited on silicon and aluminum substrates using the dip-coating technique. The content of the anatase phase and the crystallite size at different annealing temperatures were monitored using X-ray diffraction. The course of the thermal decomposition was followed using thermal analyses. The morphology, particle size, shape and elemental makeup of the samples were investigated using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The results showed that the phosphate ions successfully inhibited the growth of the anatase nanoparticles and delayed the phase transition to the rutile phase.

  8. A direct differential method for measuring thermal conductivity of thin films

    Science.gov (United States)

    Zeng, Yuqiang; Marconnet, Amy

    2017-04-01

    Over the past two decades, significant progress in the thermal metrology for thin films and wires has enabled new understanding of the thermal conductivity of nanostructures. However, a large variation in the measured thermal conductivity of similar nanostructured samples has been observed. In addition to potential differences from sample-to-sample, measurement uncertainty contributes to the observed variation in measured properties. Many now standard micro/nanoscale thermal measurement techniques require extensive calibration of the properties of the substrate and support structures and this calibration contributes to uncertainty. Within this work, we develop a simple, direct differential electrothermal measurement of thermal conductivity of micro/nanoscale sample films by extending conventional steady state electrothermal approaches. Specifically, we leverage a cross-beam measurement structure consisting of a suspended, composite heater beam (metal on silicon) with the sample structure (silicon) extending at a right angle from the center of the heater beam, in a configuration similar to the T-type measurements used for fibers and nanotubes. To accurately resolve the thermal conductivity of the sample, the steady-state Joule heating response of the cross-beam structure is measured. Then, the sample is detached from the heater beam with a Focused Ion Beam (FIB) tool enabling direct characterization of the composite heater beam thermal properties. The differential measurement of the structure before and after FIB cut enables direct extraction of the sample thermal conductivity. The effectiveness of this differential measurement technique is demonstrated by measuring thermal conductivity of a 200 nm silicon layer. Additionally, this new method enables investigation of the accuracy of conventional approaches for extracting sample thermal conductivity with the composite beam structure and conventional comparative approaches. The results highlight the benefits of the

  9. A direct differential method for measuring thermal conductivity of thin films.

    Science.gov (United States)

    Zeng, Yuqiang; Marconnet, Amy

    2017-04-01

    Over the past two decades, significant progress in the thermal metrology for thin films and wires has enabled new understanding of the thermal conductivity of nanostructures. However, a large variation in the measured thermal conductivity of similar nanostructured samples has been observed. In addition to potential differences from sample-to-sample, measurement uncertainty contributes to the observed variation in measured properties. Many now standard micro/nanoscale thermal measurement techniques require extensive calibration of the properties of the substrate and support structures and this calibration contributes to uncertainty. Within this work, we develop a simple, direct differential electrothermal measurement of thermal conductivity of micro/nanoscale sample films by extending conventional steady state electrothermal approaches. Specifically, we leverage a cross-beam measurement structure consisting of a suspended, composite heater beam (metal on silicon) with the sample structure (silicon) extending at a right angle from the center of the heater beam, in a configuration similar to the T-type measurements used for fibers and nanotubes. To accurately resolve the thermal conductivity of the sample, the steady-state Joule heating response of the cross-beam structure is measured. Then, the sample is detached from the heater beam with a Focused Ion Beam (FIB) tool enabling direct characterization of the composite heater beam thermal properties. The differential measurement of the structure before and after FIB cut enables direct extraction of the sample thermal conductivity. The effectiveness of this differential measurement technique is demonstrated by measuring thermal conductivity of a 200 nm silicon layer. Additionally, this new method enables investigation of the accuracy of conventional approaches for extracting sample thermal conductivity with the composite beam structure and conventional comparative approaches. The results highlight the benefits of the

  10. Enhancement of YBCO thin film thermal stability under 1 ATM oxygen pressure by Intermediate Cu.sub.2./sub. O nanolayer

    Czech Academy of Sciences Publication Activity Database

    Cheng, L.; Wang, X.; Yao, X.; Wan, W.; Li, F.H.; Xiong, J.; Tao, B.W.; Jirsa, Miloš

    2010-01-01

    Roč. 114, č. 22 (2010), s. 7543-7547 ISSN 1520-6106 R&D Projects: GA MŠk(CZ) ME10069 Institutional research plan: CEZ:AV0Z10100520 Keywords : YBCO thin films * thermal stability * thin film growth orientation * temperature optical microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.603, year: 2010

  11. A fast ramp rate thermally stimulated current technique to quantify electronic charge dynamics in thin films.

    Science.gov (United States)

    Lew, Connie; Thompson, Michael O

    2008-04-01

    Thermally stimulated current (TSC) techniques have been applied to study thermally activated events in many materials. However, the temperature ramp rates in traditional TSC are typically too slow (few degrees per minute) to monitor materials whose properties are strongly time dependent. A fast ramp rate TSC (FR-TSC) technique was developed with ramp rates of 1-5 K/s. This is up to 100 times faster than traditional TSC, so that material changes can be appropriately quantified in the time scale at which they take place. In this paper, the experimental design and challenges to achieve fast and stable ramp rates and to measure the low-level currents are discussed. The fast ramps were attained using a thermoelectric cooler, controlled by a proportional-integral-derivative feedback loop, for both heating and cooling. FR-TSC measurements (1 K/s and 20-100 degrees C) on poly(vinylidene fluoride-trifluoroethylene) ferroelectric thin films are discussed as an example material. From these measurements, thermally activated currents as well as irreversible and reversible charge dynamics were readily distinguished with multiple thermal cycles. These measurements suggest that this technique holds substantial promise in quantifying charge dynamics in fast response materials.

  12. Defect induced phonon scattering for tuning the lattice thermal conductivity of SiO2 thin films

    Directory of Open Access Journals (Sweden)

    Sen Cao

    2017-01-01

    Full Text Available In this work, the thermal properties of nanoscale SiO2 thin films have been systematically investigated with respect to the thickness, crystal orientations and the void defects using non-equilibrium molecular-dynamics (NEMD simulation. Size effect for the lattice thermal conductivity of nanoscale SiO2 thin films was observed. Additionally, SiO2 thin films with [001] oriented exhibited greater thermal conductivity compared with other crystal orientations which was discussed in terms of phonon density of states (PDOS. Furthermore, the porosity of void defects was introduced to quantify the influence of defects for thermal conductivity. Results exhibited that the thermal conductivity degraded with the increase of porosity. Two thermal conductivity suppression mechanisms, namely, void defects induced material loss interdicting heat conduction and phonon scattering enhanced by the boundary of defects, were proposed. Then, a further simulation was deployed to find that the effect of boundary scattering of defects was dominant in thermal conductivity degradation compared with material loss mechanism. The conclusion suggests that the thermal conductivity could be configured via regulating the distribution of PDOS directly associated with void defects.

  13. In6Se7 thin films by heating thermally evaporated indium and chemical bath deposited selenium multilayers

    International Nuclear Information System (INIS)

    Ornelas, R.E.; Avellaneda, D.; Shaji, S.; Castillo, G.A.; Roy, T.K. Das; Krishnan, B.

    2012-01-01

    Indium selenide (In 6 Se 7 ) thin films were prepared via selenization of thermally evaporated indium thin films by dipping in sodium selenosulphate solution followed by annealing in nitrogen atmosphere. First, indium was thermally evaporated on glass substrate. Then, the indium coated glass substrates were dipped in a solution containing 80 ml 0.125 M sodium selenosulphate and 1.5 ml dilute acetic acid (25%) for 5 min. Glass/In-Se layers were annealed at 200-400 °C in nitrogen atmosphere (0.1 Torr) for 30 min. X-ray diffraction studies showed the formation of monoclinic In 6 Se 7 . Morphology of the thin films formed at different conditions was analyzed using Scanning electron microscopy. The elemental analysis was done using Energy dispersive X-ray detection. Electrical conductivity under dark and illumination conditions was evaluated. Optical band gap was computed using transmittance and reflectance spectra. The band gap value was in the range 1.8-2.6 eV corresponding to a direct allowed transition. We studied the effect of indium layer thickness and selenium deposition time on the structure, electrical and optical properties of In 6 Se 7 thin films.

  14. Steady heat conduction-based thermal conductivity measurement of single walled carbon nanotubes thin film using a micropipette thermal sensor.

    Science.gov (United States)

    Shrestha, R; Lee, K M; Chang, W S; Kim, D S; Rhee, G H; Choi, T Y

    2013-03-01

    In this paper, we describe the thermal conductivity measurement of single-walled carbon nanotubes thin film using a laser point source-based steady state heat conduction method. A high precision micropipette thermal sensor fabricated with a sensing tip size varying from 2 μm to 5 μm and capable of measuring thermal fluctuation with resolution of ±0.01 K was used to measure the temperature gradient across the suspended carbon nanotubes (CNT) film with a thickness of 100 nm. We used a steady heat conduction model to correlate the temperature gradient to the thermal conductivity of the film. We measured the average thermal conductivity of CNT film as 74.3 ± 7.9 W m(-1) K(-1) at room temperature.

  15. An On-Line Method for Thermal Diffusivity Detection of Thin Films Using Infrared Video

    Directory of Open Access Journals (Sweden)

    Dong Huilong

    2016-03-01

    Full Text Available A novel method for thermal diffusivity evolution of thin-film materials with pulsed Gaussian beam and infrared video is reported. Compared with common pulse methods performed in specialized labs, the proposed method implements a rapid on-line measurement without producing the off-centre detection error. Through mathematical deduction of the original heat conduction model, it is discovered that the area s, which is encircled by the maximum temperature curve rTMAX(θ, increases linearly over elapsed time. The thermal diffusivity is acquired from the growth rate of the area s. In this study, the off-centre detection error is avoided by performing the distance regularized level set evolution formulation. The area s was extracted from the binary images of temperature variation rate, without inducing errors from determination of the heat source centre. Thermal diffusivities of three materials, 304 stainless steel, titanium, and zirconium have been measured with the established on-line detection system, and the measurement errors are: −2.26%, −1.07%, and 1.61% respectively.

  16. Oxidation and crystallization behavior of calcium europium silicon nitride thin films during rapid thermal processing

    Energy Technology Data Exchange (ETDEWEB)

    Jong, M. de, E-mail: m.dejong-1@tudelft.nl [Faculty of Applied Science, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Enter, V.E. van, E-mail: vvanenter@gmail.com [Faculty of Applied Science, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands); Schuring, E.W., E-mail: schuring@ecn.nl [Energy Center of the Netherlands, Westerduinweg 3, 1755LE Petten (Netherlands); Kolk, E. van der, E-mail: e.vanderkolk@tudelft.nl [Faculty of Applied Science, Delft University of Technology, Mekelweg 15, 2629JB Delft (Netherlands)

    2016-03-31

    Luminescent thin films were fabricated on silicon wafers using reactive magnetron sputtering of Ca, Si and Eu in Ar/N{sub 2} atmosphere. In order to activate the luminescence, the as-deposited nitride films were heated to 1100 °C by a rapid thermal processing treatment. X-ray diffraction measurements reveal the crystal phases that form during thermal treatment. By recording scanning electron microscopy images of the surface and the cross-section of the film at different radial locations, the formation of different layers with a thickness depending on the radial position is revealed. Energy dispersive x-ray spectroscopy analysis of these cross-sections reveals the formation of an oxide top layer and a nitride bottom layer. The thickness of the top layer increases as a function of radial position on the substrate and the thickness of the bottom layer decreases accordingly. The observation of different 4f{sup 6}5d{sup 1} → 4f{sup 7} Eu{sup 2+} luminescence emission bands at different radial positions correspond to divalent Eu doped Ca{sub 3}Si{sub 2}O{sub 4}N{sub 2}, Ca{sub 2}SiO{sub 4} and CaSiO{sub 3}, which is in agreement with the phases identified by X-ray diffraction analysis. A mechanism for the observed oxidation process of the nitride films is proposed that consists of a stepwise oxidation from the as-deposited amorphous nitride state to crystalline Ca{sub 3}Si{sub 2}O{sub 4}N{sub 2}, to Ca{sub 2}SiO{sub 4} and finally CaSiO{sub 3}. The oxidation rate and final state of oxidation show a strong temperature–time dependency during anneal treatment. - Highlights: • A thin film of nitridated Ca, Si and Eu was deposited using magnetron sputtering. • Rapid thermal processing (RTP) results in Eu{sup 2+} doped Ca{sub 3}Si{sub 2}O{sub 4}N{sub 2}, Ca{sub 2}SiO{sub 4}, and CaSiO{sub 3}. • Oxidation rate differs with radial position due to a temperature gradient during RTP. • Cross-section SEM–EDX shows how the oxidation progresses in lateral direction.

  17. Supramolecular structure of a perylene derivative in thin films made by vacuum thermal evaporation

    International Nuclear Information System (INIS)

    Fernandes, Jose Diego

    2015-01-01

    The supramolecular arrangement of organic thin films is a factor that influences both optical and electrical properties of these films and, consequently, the technological applications involving organic electronics. In this dissertation, thin films of a perylene derivative (bis butylimido perylene, acronym BuPTCD) were produced by physical vapor deposition (PVD) using vacuum thermal evaporation. The aim of this work was to investigate the supramolecular arrangement of BuPTCD films, which implies to control the thickness at nanometer scale and to determine the molecular organization, the morphology (at nano and micrometer scales) and the crystallinity, besides the stability of this arrangement as a function of the temperature. Optical properties (such as absorption and emission) and electrical properties (such as conductivity and photoconductivity) were also determined. The UV-Vis absorption spectra revealed a controlled growth (uniform) of the BuPTCD films. Atomic force and optical microscopy images showed a homogeneous surface of the film at nano and micrometer scales, respectively. The X-ray diffraction showed that the BuPTCD powder and PVD film have different crystalline structures, with the BuPTCD molecules head-on oriented in the PVD films, supported on the substrate surface by the side group (FTIR). This structure favors the light emission (photoluminescence) by the formation of excimers. The thermal treatment (200°C for 10 min) does not affect the molecular organization of the PVD films, showing a thermal stability of the BuPTCD supramolecular arrangement under these circumstances. The electrical measurements (DC) showed a linear increase of the current as a function of the tension, which is characteristic of ohmic behavior. Also, the films exhibited an increase of current by 2 orders of magnitude when exposed to light (photoconductive properties). Finally, BuPTCD films were exposed to vapor of trifluoroacetic acid (TFA) to verify the sensitivity of the Bu

  18. Design and fabrication of a spatial light modulator using thermally tunable grating and a thin-film heater.

    Science.gov (United States)

    Riahi, Mohammadreza; Latifi, Hamid; Madani, Abbas; Moazzenzadeh, Ali

    2009-10-20

    We propose the application of a thermally tunable grating as a spatial light modulator. The grooves of a square-well grating are filled with a liquid whose refractive index depends on temperature. The variation of optical characteristics of such a grating with respect to temperature is investigated theoretically and also by simulation and experiment. A thin-film heater is then used as a heat source. The relation between intensity of the first order of diffraction versus power consumption of the thin-film heater is investigated. Finally, a thin-film heater with a desired pattern is placed at the surface of the grating to fabricate spatial light modulator. By applying electrical current to different elements of the thin-film heater, the fabricated device can project a desired pattern on a screen using a 4f imaging system. The restrictions of such a device are discussed and another structure is proposed and discussed by numerical calculations to increase the ability of the device.

  19. Growth, structural, electrical and optical properties of the thermally evaporated tungsten trioxide (WO{sub 3}) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Patel, K.J. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara 390001, Gujarat (India); Panchal, C.J. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara 390001, Gujarat (India)], E-mail: cjpanchal_msu@yahoo.com; Kheraj, V.A.; Desai, M.S. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara 390001, Gujarat (India)

    2009-03-15

    Tungsten trioxide (WO{sub 3}) thin films are of great interest due to their enormous and promising applications in various opto-electronic thin-film devices. We have investigated the structural, electrical, and optical properties of the WO{sub 3} thin films grown by thermal evaporation of WO{sub 3} powder and their dependence on growth condition. The WO{sub 3} thin films were grown on glass substrates at different substrate temperature varying from room temperature to 510 deg. C. The structural characterization and surface morphology were carried out using X-ray diffraction and atomic force microscopy, respectively. The amorphous films were obtained at substrate temperatures below 450 deg. C whereas films grown above 450 deg. C were crystalline. The surface roughness and the grain size of the films increase on increasing the substrate temperature. The electrical characterization has been carried out using four-point-probe methods. The resistivity of the films decreases significantly while the carrier concentration and mobility increase with the substrate temperature. The transparency and optical energy band-gap, E{sub g}, of the films are found to decrease monotonically as the substrate temperature increases.

  20. Vertically self-ordered orientation of nanocrystalline hexagonal boron nitride thin films for enhanced thermal characteristics.

    Science.gov (United States)

    Cometto, Olivier; Sun, Bo; Tsang, Siu Hon; Huang, Xi; Koh, Yee Kan; Teo, Edwin Hang Tong

    2015-12-07

    Vertically self-ordered hexagonal boron nitride (ordered h-BN) is a highly ordered turbostratic BN (t-BN) material similar to hexagonal BN, with its planar structure perpendicularly oriented to the substrate. The ordered h-BN thin films were grown using a High Power Impulse Magnetron Sputtering (HiPIMS) system with a lanthanum hexaboride (LaB6) target reactively sputtered in nitrogen gas. The best vertical alignment was obtained at room temperature, with a grounded bias and a HiPIMS peak power density of 60 W cm(-2). Even though the film contains up to 7.5 at% lanthanum, it retains its highly insulative properties and it was observed that an increase in compressive stress is correlated to an increase in film ordering quality. Importantly, the thermal conductivity of vertically ordered h-BN is considerably high at 5.1 W m(-1) K(-1). The favourable thermal conductivity coupled with the dielectric properties of this novel material and the low temperature growth could outperform SiO2 in high power density electronic applications.

  1. Radio-frequency magnetron sputtering and wet thermal oxidation of ZnO thin film

    International Nuclear Information System (INIS)

    Liu, H. F.; Chua, S. J.; Hu, G. X.; Gong, H.; Xiang, N.

    2007-01-01

    The authors studied the growth and wet thermal oxidation (WTO) of ZnO thin films using a radio-frequency magnetron sputtering technique. X-ray diffraction reveals a preferred orientation of [1010]ZnO(0002)//[1120]Al 2 O 3 (0002) coexisted with a small amount of ZnO (1011) and ZnO (1013) crystals on the Al 2 O 3 (0001) substrate. The ZnO (1011) and ZnO (1013) crystals, as well as the in-plane preferred orientation, are absent from the growth of ZnO on the GaAs(001) substrate. WTO at 550 deg. C improves the crystalline and the photoluminescence more significantly than annealing in air, N 2 and O 2 ambient; it also tends to convert the crystal from ZnO (1011) and ZnO (1013) to ZnO (0002). The evolution of the photoluminescence upon WTO and annealing reveals that the green and orange emissions, centered at 520 and 650 nm, are likely originated from oxygen vacancies and oxygen interstitials, respectively; while the 420 nm emission, which is very sensitive to the postgrowth thermal processing regardless of the substrate and the ambient gas, is likely originated from the surface-state related defects

  2. Phase transition and thermal expansion studies of alumina thin films prepared by reactive pulsed laser deposition.

    Science.gov (United States)

    Balakrishnan, G; Thirumurugesan, R; Mohandas, E; Sastikumar, D; Kuppusami, P; Songl, J I

    2014-10-01

    Aluminium oxide (Al2O3) thin films were deposited on Si (100) substrates at an optimized oxygen partial pressure of 3 x 10(-3) mbar at room temperature by pulsed laser deposition (PLD). The films were characterized by high temperature X-ray diffraction (HTXRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The HTXRD pattern showed the cubic y-Al2O3 phase in the temperature range 300-973 K. At temperatures ≥ 1073 K, the δ and θ-phases of Al2O3 were observed. The mean linear thermal expansion coefficient and volume thermal expansion coefficient of γ-Al2O3 was found to be 12.66 x 10(-6) K(-1) and 38.87 x 10(-6) K(-1) in the temperature range 300 K-1073 K. The field emission scanning electron microscopy revealed a smooth and structureless morphology of the films deposited on Si (100). The atomic force microscopy study indicated the increased crystallinity and surface roughness of the films after annealing at high temperature.

  3. Quantifying the stress relaxation modulus of polymer thin films via thermal wrinkling.

    Science.gov (United States)

    Chan, Edwin P; Kundu, Santanu; Lin, Qinghuang; Stafford, Christopher M

    2011-02-01

    The viscoelastic properties of polymer thin films can have a significant impact on the performance in many small-scale devices. In this work, we use a phenomenon based on a thermally induced instability, termed thermal wrinkling, to measure viscoelastic properties of polystyrene films as a function of geometric confinement via changes in film thickness. With application of the appropriate buckling mechanics model for incompressible and geometrically confined films, we estimate the stress-relaxation modulus of polystyrene films by measuring the time-evolved wrinkle wavelength at fixed annealing temperatures. Specifically, we use time-temperature superposition to shift the stress relaxation curves and generate a modulus master curve for polystyrene films investigated here. On the basis of this master curve, we are able to identify the rubbery plateau, terminal relaxation time, and viscous flow region as a function of annealing time and temperatures that are well-above its glass transition. Our measurement technique and analysis provide an alternative means to measure viscoelastic properties and relaxation behavior of geometrically confined polymer films.

  4. The measuring technique developed to evaluate the thermal diffusivity of the multi-layered thin film specimens

    Directory of Open Access Journals (Sweden)

    Li Tse-Chang

    2017-01-01

    Full Text Available In the present study, the thermal diffusivities of the Al, Si and ITO films deposited on the SUS304 steel substrate are evaluated via the present technique. Before applying this technique, the temperature for the thin film of the multi-layered specimen is developed theoretically for the one- dimensional steady heat conduction in response to amplitude and frequency of the periodically oscillating temperature imposed by a peltier placed beneath the specimen's substrate. By the thermal-electrical data processing system excluding the lock-in amplifier, the temperature frequency a3 has been proved first to be independent of the electrical voltage applied to the peltier and the contact position of the thermocouples. The experimental data of phase difference for three kinds of specimen are regressed well by a straight line with a slope. Then, the thermal diffusivity of the thin film is thus determined if the slope value and the film- thickness are available. In the present arrangements for the thermocouples, two thermal diffusivity values are quite close each other and valid for every kind of specimen. This technique can provide an efficient, low-cost method for the thermal diffusivity measurements of thin films.

  5. Thin Film

    African Journals Online (AJOL)

    a

    organic substances. KEY WORDS: Photoelectrocatalysis, Titanium dioxide, Cuprous oxide, Composite thin film, Photo electrode. INTRODUCTION ... reddish p-type semiconductor with a direct band gap of 2.0-2.2 eV [18, 19]. ... Photoelectrocatalytic removal of color from water using TiO2 and TiO2/Cu2O electrodes. Bull.

  6. Photo-induced and thermal reactions in thin films of an azobenzene derivative on Bi(111)

    Science.gov (United States)

    Bronner, Christopher; Tegeder, Petra

    2014-05-01

    Azobenzene is a prototypical molecular switch which can be interconverted with UV and visible light between a trans and a cis isomer in solution. While the ability to control their conformation with light is lost for many molecular photoswitches in the adsorbed state, there are some examples for successful photoisomerization in direct contact with a surface. However, there the process is often driven by a different mechanism than in solution. For instance, photoisomerization of a cyano-substituted azobenzene directly adsorbed on Bi(111) occurs via electronic excitations in the substrate and subsequent charge transfer. In the present study we observe two substrate-mediated trans-cis photoisomerization reactions of the same azobenzene derivative in two different environments within a multilayer thin film on Bi(111). Both processes are associated with photoisomerization and one is around two orders of magnitude more efficient than the other. Furthermore, the cis isomers perform a thermally induced reaction which may be ascribed to a back-isomerization in the electronic ground state or to a phenyl ring rotation of the cis isomer.

  7. Thermal Treatment Dependence of the Electronic Structure of Thin Film Amorphous Boron Carbides

    Science.gov (United States)

    Driver, M. S.; Sandstrom, J.; Boyko, T.; Moewes, A.; Pokhodnya, K. I.; Li, W.; Oyler, N. A.; Caruso, A. N.

    2011-03-01

    Boron-rich semiconducting solids are important materials for next generation direct conversion solid state neutron detectors. However, rigorous understanding of the fundamental properties of these solids is drastically lacking and required before optimization of the neutron detectors may occur. To partially resolve this inadequacy, we have studied and compared the electronic and local physical structure relationship of thins films of amorphous hydrogenated boron carbide (a-B5 C:Hx) deposited by PECVD and quasicrystalline technical boron carbide (B4 C:Cy) deposited by RF MS. In an attempt to understand the near Fermi edge structure in slightly modified local environments, x-ray absorption and emission spectroscopies (XAS/XES), ultraviolet photoemission, x-ray photoemission, and solid state NMR were collected at 300 K on films thermally treated from 300 to 1100 K. The electronic structure studies reveal a unique alteration of π * and σ * states and overall chemical reduction for the 600 K and above annealed films. The solid state NMR, in comparison with reference samples, reveals a slow ordering progression; this allows us to describe the relationship between intra- and inter-icosahedral carbon on the overall electronic structure.

  8. Comparison of four-probe thermal and thermoelectric transport measurements of thin films and nanostructures with microfabricated electro-thermal transducers

    Science.gov (United States)

    Kim, Jaehyun; Fleming, Evan; Zhou, Yuanyuan; Shi, Li

    2018-03-01

    Two different four-probe thermal and thermoelectric measurement methods have been reported for measuring the thermal conductivity, Seebeck coefficient, and electrical conductivity of suspended thin films and nanostructures with microfabricated electro-thermal transducers. The thermal contact resistance was extracted from the measured thermoelectric voltage drop at the contacts in the earlier four-probe method based on the assumption of constant thermal and thermoelectric properties along the sample. In comparison, the latter four-probe method can directly obtain the contact thermal resistance together with the intrinsic sample thermal resistance without making this assumption. Here, the measurement theory and data reduction processes of the latter four-probe measurement method are re-examined and improved. The measured thermal conductivity result of this improved method on representative thin film samples are found to agree with those obtained from the earlier four-probe method, which has obtained similar Seebeck coefficient and electrical conductivity as those measured with a different method for a supported thin film. The agreement provides further validation of the latest four-probe thermal transport measurement method of thin films and nanostructures.

  9. Annealing study and thermal investigation on bismuth sulfide thin films prepared by chemical bath deposition in basic medium

    Science.gov (United States)

    Dachraoui, O.; Merino, J. M.; Mami, A.; León, M.; Caballero, R.; Maghraoui-Meherzi, H.

    2018-02-01

    Bismuth sulfide thin films were prepared by chemical bath deposition using thiourea as sulfide ion source in basic medium. First, the effects of both the deposition parameters on film growth as well as the annealing effect under argon and sulfur atmosphere on as-deposited thin films were studied. The parameters were found to be influential using the Doehlert matrix experimental design methodology. Ranges for a maximum surface mass of films (3 mg cm-2) were determined. A well-crystallized major phase of bismuth sulfide with stoichiometric composition was achieved at 190 °C for 3 h. The prepared thin films were characterized using grazing incidence X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis. Second, the bandgap energy value was found to be 1.5 eV. Finally, the thermal properties have been studied for the first time by means of the electropyroelectric (EPE) technique. Indeed, the thermal conductivity varied in the range of 1.20-0.60 W m-1 K-1, while the thermal diffusivity values increased in terms of the annealing effect ranging from 1.8 to 3.5 10-7 m2 s-1.

  10. Thermal stability of diamond-like carbon–MoS{sub 2} thin films in different environments

    Energy Technology Data Exchange (ETDEWEB)

    Niakan, H., E-mail: hamid.niakan@usask.ca [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Zhang, C. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Hu, Y. [Canadian Light Source, 101 Perimeter Road, Saskatoon, SK S7N 0X4 (Canada); Szpunar, J.A.; Yang, Q. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada)

    2014-07-01

    Diamond-like carbon (DLC) based coatings are ideal for low friction and wear resistant applications. For those tribological applications, the coatings may expose to high temperature environments. Therefore, the thermal stability of the coating is very important for its long-term performance. In this work, DLC–MoS{sub 2} composite thin films were synthesized using biased target ion beam deposition technique in which MoS{sub 2} was produced by sputtering a MoS{sub 2} target using Ar ion beams while DLC was deposited by an ion source with CH{sub 4} gas as carbon source. DLC films without MoS{sub 2} deposited under similar conditions were used as reference samples. After the deposition, DLC and DLC–MoS{sub 2} thin films were heat-treated in ambient air and low pressure environments at different temperatures ranging from 100 to 600 °C for 2 h. The effect of annealing on the structure, mechanical and tribological properties of the resulting films were studied by means of Raman spectroscopy, X-ray absorption near edge structure, scanning electron microscopy, nanoindentation, and ball-on-disk testing. The results showed that the structure, hardness, Young's modulus, friction coefficient and wear coefficient of the DLC films were stable up to 200 °C annealing in air and 300 °C in low pressure. At higher temperature, the annealing led to the transformation of sp{sup 3} to sp{sup 2}, which degraded the mechanical and tribological properties of the thin films. Comparing with the DLC films, the DLC–MoS{sub 2} thin films showed a slower rate of graphitization and higher structure stability throughout the range of annealing temperatures, indicating a relatively higher thermal stability. - Highlights: • Thermal stability of diamond-like carbon (DLC) and DLC–MoS{sub 2} films were evaluated. • DLC–MoS{sub 2} films can be synthesized by biased target ion beam deposition technique. • Comparing with DLC films, the DLC–MoS{sub 2} thin films showed higher

  11. Deuterium thermal desorption from Ni-rich deuterated Mg thin films

    Energy Technology Data Exchange (ETDEWEB)

    Patel, N.; Kale, A.; Mosaner, P.; Checchetto, R.; Miotello, A. [Dipartimento di Fisica dell' Universita di Trento, I-38050 Povo (Italy); Das, G. [Dipartimento di Medicina Sperimentale e Clinica, Universita degli Studi, Magna Grecia, I-88100 Catanzaro (Italy)

    2008-02-15

    Mg-Ni multilayers and Ni-rich Mg thin films were deposited by electron gun and pulsed laser deposition, respectively. Samples were submitted to thermal treatment in deuterium or hydrogen atmosphere at 423 K and {proportional_to}10{sup 5} Pa pressure to promote the metal to hydride phase transition. The H chemical bonding in the multilayer samples, after annealing in H{sub 2} atmosphere, was examined by Fourier transform infrared spectroscopy: the obtained spectra suggest that the samples with the Mg:Ni=2:1 atomic ratio contain the Mg{sub 2}NiH{sub 4} phase while the samples with lower Ni concentration contain both the MgH{sub 2} and the Mg{sub 2}NiH{sub 4} phases. The effect of the Ni additive on the stability of the deuteride phase was studied by thermal desorption spectroscopy (TDS). The TDS spectra of the single-phase Mg{sub 2}NiD{sub 4} samples show a TDS peak at 400 K. The TDS spectra of the two-phase samples show both the D{sub 2} desorption peak at 400 K and a second peak at higher temperature that we attributed to the dissociation of the MgD{sub 2} phase. The high-temperature peak shifts to lower temperatures by increasing the Ni content. It is suggested that in the two-phase samples, the lattice volumes having the Mg{sub 2}Ni structure resulting from the dissociation of the Mg{sub 2}NiD{sub 4} phase reduce the thermodynamic stability of the MgD{sub 2} phase. (author)

  12. Optical thin film deposition

    International Nuclear Information System (INIS)

    Macleod, H.A.

    1979-01-01

    The potential usefulness in the production of optical thin-film coatings of some of the processes for thin film deposition which can be classified under the heading of ion-assisted techniques is examined. Thermal evaporation is the process which is virtually universally used for this purpose and which has been developed to a stage where performance is in almost all respects high. Areas where further improvements would be of value, and the possibility that ion-assisted deposition might lead to such improvements, are discussed. (author)

  13. Current-induced metal-insulator transition in VO x thin film prepared by rapid-thermal-annealing

    International Nuclear Information System (INIS)

    Cho, Choong-Rae; Cho, SungIl; Vadim, Sidorkin; Jung, Ranju; Yoo, Inkyeong

    2006-01-01

    The phenomenon of metal-insulator transition (MIT) in polycrystalline VO x thin films and their preparations have been studied. The films were prepared by sputtering of vanadium thin films succeeded by Rapid Thermal Annealing (RTA) in oxygen ambient at 500 deg. C. Crystalline, compositional, and morphological characterizations reveal a continuous change of phase from vanadium metal to the highest oxide phase, V 2 O 5 , with the time of annealing. Electrical MIT switching has been observed in these films. Sweeping mode, electrode area, and temperature dependent MIT has been studied in Pt/VO x /Pt vertical structure. The important parameters for MIT in VO x have been found to be the current density and the electric field, which depend on carrier density in the films

  14. Patterning of metallic electrodes on flexible substrates for organic thin-film transistors using a laser thermal printing method

    International Nuclear Information System (INIS)

    Chen, Kun-Tso; Lin, Yu-Hsuan; Ho, Jeng-Rong; Chen, Chih-Kant; Liu, Sung-Ho; Liao, Jin-Long; Cheng, Hua-Chi

    2011-01-01

    We report on a laser thermal printing method for transferring patterned metallic thin films on flexible plastic substrates using a pulsed CO 2 laser. Aluminium and silver line patterns, with micrometre scale resolution on poly(ethylene terephthalate) substrates, are shown. The printed electrodes demonstrate good conductivity and fulfil the properties for bottom-contact organic thin-film transistors. In addition to providing the energy for transferring the film, the absorption of laser light results in a rise in the temperature of the film and the substrate. This also further anneals the film and softens the plastic substrate. Consequently, it is possible to obtain a film with better surface morphology and with its film thickness implanted in part into the plastic surface. This implantation reveals excellent characteristics in adhesion and flexure resistance. Being feasible to various substrates and executable at ambient temperatures renders this approach a potential alternative for patterning metallic electrodes.

  15. Optical and Morphological Studies of Thermally Evaporated PTCDI-C8 Thin Films for Organic Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Ronak Rahimi

    2013-01-01

    Full Text Available PTCDI-C8 due to its relatively high photosensitivity and high electron mobility has attracted much attention in organic semiconductor devices. In this work, thin films of PTCDI-C8 with different thicknesses were deposited on silicon substrates with native silicon dioxide using a vacuum thermal evaporator. Several material characterization techniques have been utilized to evaluate the structure, morphology, and optical properties of these films. Their optical constants (refractive index and extinction coefficient have been extracted from the spectroscopic ellipsometry (SE. X-ray reflectivity (XRR and atomic force microscopy (AFM were employed to determine the morphology and structure as well as the thickness and roughness of the PTCDI-C8 thin films. These films revealed a high degree of structural ordering within the layers. All the experimental measurements were performed under ambient conditions. PTCDI-C8 films have shown to endure ambient condition which allows pots-deposition characterization.

  16. Fabrication and Characterization of High-Crystalline Nanoporous ZnO Thin Films by Modified Thermal Evaporation System

    Science.gov (United States)

    Islam, M. S.; Hossain, M. F.; Razzak, S. M. A.; Haque, M. M.; Saha, D. K.

    2016-05-01

    The aim of this work is to fabricate high-crystalline nanoporous zinc oxide (ZnO) thin films by a modified thermal evaporation system. First, zinc thin films have been deposited on bare glass substrate by the modified thermal evaporation system with pressure of 0.05mbar, source-substrate distance of 3cm and source temperature 700∘C. Then, high-crystalline ZnO thin film is obtained by annealing at 500∘C for 2h in atmosphere. The prepared ZnO films are characterized with various deposition times of 10min and 20min. The structural property was investigated by X-ray diffractometer (XRD). The optical bandgap and absorbance/transmittance of these films are examined by ultraviolet/visible spectrophotometer. The surface morphological property has been observed by scanning electron microscope (SEM). ZnO films have showed uniform nanoporous surface with high-crystalline hexagonal wurtzite structure. The ZnO films prepared with 20min has excitation absorption-edge at 369nm, which is blueshifted with respect to the bulk absorption-edge appearing at 380nm. The gap energy of ZnO film is decreased from 3.14eV to 3.09eV with increase of the deposition time, which can enhance the excitation of ZnO films by the near visible light, and is suitable for the application of photocatalyst of waste water cleaning and polluted air purification.

  17. Annealing Effect on the Thermoelectric Properties of Bi2Te3 Thin Films Prepared by Thermal Evaporation Method

    Directory of Open Access Journals (Sweden)

    Jyun-Min Lin

    2013-01-01

    Full Text Available Bismuth telluride-based compounds are known to be the best thermoelectric materials within room temperature region, which exhibit potential applications in cooler or power generation. In this paper, thermal evaporation processes were adopted to fabricate the n-type Bi2Te3 thin films on SiO2/Si substrates. The influence of thermal annealing on the microstructures and thermoelectric properties of Bi2Te3 thin films was investigated in temperature range 100–250°C. The crystalline structures and morphologies were characterized by X-ray diffraction and field emission scanning electron microscope analyses. The Seebeck coefficients, electrical conductivity, and power factor were measured at room temperature. The experimental results showed that both the Seebeck coefficient and power factor were enhanced as the annealing temperature increased. When the annealing temperature increased to 250°C for 30 min, the Seebeck coefficient and power factor of n-type Bi2Te3-based thin films were found to be about −132.02 μV/K and 6.05 μW/cm·K2, respectively.

  18. Thermal recrystallization of physical vapor deposition based germanium thin films on bulk silicon (100)

    KAUST Repository

    Hussain, Aftab M.

    2013-08-16

    We demonstrate a simple, low-cost, and scalable process for obtaining uniform, smooth surfaced, high quality mono-crystalline germanium (100) thin films on silicon (100). The germanium thin films were deposited on a silicon substrate using plasma-assisted sputtering based physical vapor deposition. They were crystallized by annealing at various temperatures ranging from 700 °C to 1100 °C. We report that the best quality germanium thin films are obtained above the melting point of germanium (937 °C), thus offering a method for in-situ Czochralski process. We show well-behaved high-κ /metal gate metal-oxide-semiconductor capacitors (MOSCAPs) using this film. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Thin films and nanomaterials

    International Nuclear Information System (INIS)

    Jayakumar, S.; Kannan, M.D.; Prasanna, S.

    2012-01-01

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

  20. thin films

    Indian Academy of Sciences (India)

    The anionic precursor was 1% H2O2 solution. Both the cationic and anionic precursors were kept at room temperature (∼300 K). One SILAR cycle consists of two steps: (i) adsorption of Sn4+ ions on the substrate surface for 20 s and (ii) reaction with H2O2 solution for 40 s to form stable SnO2:H2O thin film on the substrate.

  1. Transparent thin-film transistor exploratory development via sequential layer deposition and thermal annealing

    International Nuclear Information System (INIS)

    Hong, David; Chiang, Hai Q.; Presley, Rick E.; Dehuff, Nicole L.; Bender, Jeffrey P.; Park, Cheol-Hee; Wager, John F.; Keszler, Douglas A.

    2006-01-01

    A novel deposition methodology is employed for exploratory development of a class of high-performance transparent thin-film transistor (TTFT) channel materials involving oxides composed of heavy-metal cations with (n - 1)d 10 ns 0 (n ≥ 4) electronic configurations. The method involves sequential radio-frequency sputter deposition of thin, single cation oxide layers and subsequent post-deposition annealing in order to obtain a multi-component oxide thin film. The viability of this rapid materials development methodology is demonstrated through the realization of high-performance TTFTs with channel layers composed of zinc oxide/tin oxide, and tin oxide/indium oxide

  2. Thermally evaporated mechanically hard tin oxide thin films for opto-electronic apllications

    Energy Technology Data Exchange (ETDEWEB)

    Tripathy, Sumanta K.; Rajeswari, V. P. [Centre for Nano Science and Technology, GVP College of Engineering (Autonomous), Visakhapatnam- 530048 (India)

    2014-01-28

    Tungsten doped tin oxide (WTO) and Molybdenum doped tin oxide (MoTO) thin film were deposited on corn glass by thermal evaporation method. The films were annealed at 350°C for one hour. Structural analysis using Xray diffraction data shows both the films are polycrystalline in nature with monoclinic structure of tin oxide, Sn{sub 3}O{sub 4}, corresponding to JCPDS card number 01-078-6064. SEM photograph showed that both the films have spherical grains with size in the range of 20–30 nm. Compositional analysis was carried out using EDS which reveals the presence of Sn, O and the dopant Mo/W only thereby indicating the absence of any secondary phase in the films. The films are found to contain nearly 6 wt% of Mo, 8 wt% of W as dopants respectively. The transmission pattern for both the films in the spectral range 200 – 2000 nm shows that W doping gives a transparency of nearly 80% from 380 nm onwards while Mo doping has less transparency of 39% at 380nm. Film hardness measurement using Triboscope shows a film hardness of about 9–10 GPa for both the films. It indicates that W or M doping in tin oxide provides the films the added advantage of withstanding the mechanical wear and tear due to environmental fluctuations By optimizing the optical and electrical properties, W/Mo doped tin oxide films may be explored as window layers in opto-electronic applications such as solar cells.

  3. Investigations of rapid thermal annealing induced structural evolution of ZnO: Ge nanocomposite thin films via GISAXS

    Energy Technology Data Exchange (ETDEWEB)

    Ceylan, Abdullah, E-mail: aceylanabd@yahoo.com [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Ozcan, Yusuf [Department of Electricity and Energy, Pamukkale University, Denizli (Turkey); Orujalipoor, Ilghar [Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey); Huang, Yen-Chih; Jeng, U-Ser [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu, Taiwan (China); Ide, Semra [Department of Physics Eng., Hacettepe University, Beytepe, 06800 Ankara (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, Beytepe, 06800 Ankara (Turkey)

    2016-06-07

    In this work, we present in depth structural investigations of nanocomposite ZnO: Ge thin films by utilizing a state of the art grazing incidence small angle x-ray spectroscopy (GISAXS) technique. The samples have been deposited by sequential r.f. and d.c. sputtering of ZnO and Ge thin film layers, respectively, on single crystal Si(100) substrates. Transformation of Ge layers into Ge nanoparticles (Ge-np) has been initiated by ex-situ rapid thermal annealing of asprepared thin film samples at 600 °C for 30, 60, and 90 s under forming gas atmosphere. A special attention has been paid on the effects of reactive and nonreactive growth of ZnO layers on the structural evolution of Ge-np. GISAXS analyses have been performed via cylindrical and spherical form factor calculations for different nanostructure types. Variations of the size, shape, and distributions of both ZnO and Ge nanostructures have been determined. It has been realized that GISAXS results are not only remarkably consistent with the electron microscopy observations but also provide additional information on the large scale size and shape distribution of the nanostructured components.

  4. Unique Crystal Orientation of Poly(ethylene oxide) Thin Films by Crystallization Using a Thermal Gradient

    DEFF Research Database (Denmark)

    Gbabode, Gabin; Delvaux, Maxime; Schweicher, Guillaume

    2017-01-01

    Poly(ethylene oxide), (PEO), thin films of different thicknesses (220, 450, and 1500 nm) and molecular masses (4000, 8000, and 20000 g/mol) have been fabricated by spin-coating of methanol solutions onto glass substrates. All these samples have been recrystallized from the melt using a directional...

  5. Photoelectric properties of Cu2ZnSnS4 thin films deposited by thermal evaporation

    Science.gov (United States)

    Xinkun, Wu; Wei, Liu; Shuying, Cheng; Yunfeng, Lai; Hongjie, Jia

    2012-02-01

    Sn/Cu/ZnS precursor were deposited by evaporation on soda lime glass at room temperature, and then polycrystalline thin films of Cu2ZnSnS4 (CZTS) were produced by sulfurizing the precursors in a sulfur atmosphere at a temperature of 550 °C for 3 h Fabricated CZTS thin films were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, ultraviolet-visible-near infrared spectrophotometry, the Hall effect system, and 3D optical microscopy. The experimental results show that, when the ratios of [Cu]/([Zn] + [Sn]) and [Zn]/[Sn] in the CZTS are 0.83 and 1.15, the CZTS thin films possess an absorption coefficient of larger than 4.0 × 104 cm-1 in the energy range 1.5-3.5 eV, and a direct band gap of about 1.47 eV. The carrier concentration, resistivity and mobility of the CZTS film are 6.98 × 1016 cm-3, 6.96 Ω·cm, and 12.9 cm2/(V·s), respectively and the conduction type is p-type. Therefore, the CZTS thin films are suitable for absorption layers of solar cells.

  6. Thermal stability, microstructure and mechanical properties of Ti1-xZrxN thin films

    International Nuclear Information System (INIS)

    Hoerling, A.; Sjoelen, J.; Willmann, H.; Larsson, T.; Oden, M.; Hultman, L.

    2008-01-01

    Single-phase [NaCl]-structure Ti 1-x Zr x N thin films (0 1-x Zr x N films is proposed to be solid-solution hardening through local lattice strain fields originating from difference in atomic radius of Ti and Zr. The material system is thus promising for cutting tool applications

  7. Thermal expansion coefficient and thermomechanical properties of SiN(x) thin films prepared by plasma-enhanced chemical vapor deposition.

    Science.gov (United States)

    Tien, Chuen-Lin; Lin, Tsai-Wei

    2012-10-20

    We present a new method based on fast Fourier transform (FFT) for evaluating the thermal expansion coefficient and thermomechanical properties of thin films. The silicon nitride thin films deposited on Corning glass and Si wafers were prepared by plasma-enhanced chemical vapor deposition in this study. The anisotropic residual stress and thermomechanical properties of silicon nitride thin films were studied. Residual stresses in thin films were measured by a modified Michelson interferometer associated with the FFT method under different heating temperatures. We found that the average residual-stress value increases when the temperature increases from room temperature to 100°C. Increased substrate temperature causes the residual stress in SiN(x) film deposited on Si wafers to be more compressive, but the residual stress in SiN(x) film on Corning glass becomes more tensile. The residual-stress versus substrate-temperature relation is a linear correlation after heating. A double substrate technique is used to determine the thermal expansion coefficients of the thin films. The experimental results show that the thermal expansion coefficient of the silicon nitride thin films is 3.27×10(-6)°C(-1). The biaxial modulus is 1125 GPa for SiN(x) film.

  8. Thermal Management of Concentrated Multi-Junction Solar Cells with Graphene-Enhanced Thermal Interface Materials

    Directory of Open Access Journals (Sweden)

    Mohammed Saadah

    2017-06-01

    Full Text Available We report results of experimental investigation of temperature rise in concentrated multi-junction photovoltaic solar cells with graphene-enhanced thermal interface materials. Graphene and few-layer graphene fillers, produced by a scalable environmentally-friendly liquid-phase exfoliation technique, were incorporated into conventional thermal interface materials. Graphene-enhanced thermal interface materials have been applied between a solar cell and heat sink to improve heat dissipation. The performance of the multi-junction solar cells has been tested using an industry-standard solar simulator under a light concentration of up to 2000 suns. It was found that the application of graphene-enhanced thermal interface materials allows one to reduce the solar cell temperature and increase the open-circuit voltage. We demonstrated that the use of graphene helps in recovering a significant amount of the power loss due to solar cell overheating. The obtained results are important for the development of new technologies for thermal management of concentrated photovoltaic solar cells.

  9. Foam-like, microstructural SnO2-carbon composite thin films synthesized via a polyol-assisted thermal decomposition method.

    Science.gov (United States)

    Ng, See-How; Chew, Sau-Yen; Wang, Jia-Zhao; Chen, Jun; Dou, Shi-Xue; Liu, Hua-Kun

    2009-01-28

    Foam-like, microstructural SnO2-carbon composite thin films were synthesized by refluxing SnCl2.2H2O in ethylene glycol (EG) at 195 degrees C for 4 h under vigorous stirring in air followed by thermal decomposition of the as-synthesized precursor solution, whereby the products were deposited onto stainless steel (SS) substrates. Subsequently, the decomposed product, which now consists only of the microstructural SnO2-carbon composite thin film, without the addition of any binder and carbon black conductive agent, was directly applied as an anode material for use in a Li-ion rechargeable battery. Physical and electrochemical characterizations of the as-synthesized thin films were carried out. The foam-like, microstructural SnO2-carbon composite thin films that undergo thermal decomposition in air at 300 degrees C demonstrated the best cyclability, delivering a specific discharge capacity of approximately 496 mAh g(-1) beyond 100 cycles. We believe that the presence of a uniform, SnO2-carbon network throughout the foam-like thin film, acts not only as an improved conducting network but also buffered the volume expansion upon Li-Sn alloying, resulting in a much improved cycling of the composite thin film electrode.

  10. W/Cu thin film infrared reflector for TiNxOy based selective solar absorber with high thermal stability

    Science.gov (United States)

    Zhang, J.; Chen, T. P.; Liu, Y. C.; Liu, Z.; Yang, H. Y.

    2017-05-01

    The W/Cu thin film structure is deposited by magnetron sputtering to form the infrared reflector for the TiNxOy based selective solar absorber (SSA) that can be used in the low- and middle-temperature applications. The structural, chemical, and optical properties of the SSA layers that experienced thermal annealing at different temperatures for various durations have been investigated with the characterization techniques, including X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy, spectroscopic ellipsometry, and spectrophotometry. Without a W layer, the reflectance in both visible and infrared ranges of the SSA increases as a result of the crystallization of the Cu layer at elevated temperatures. With a W layer with appropriate film thickness, the increase of the reflectance in the visible range can be suppressed to maintain a high solar absorptance, whereas a high infrared reflectance can be maintained to achieve a low thermal emittance. It is shown that for the SiO2-TiNxOy-W-Cu-Glass SSA with a 15 nm W thin film, thermal annealing can significantly reduce the thermal emittance to a low value (e.g., 4.4% at the temperature of 400 °C for annealing at 400 °C for 6 h), whereas the solar absorptance can be maintained at a high value (e.g., 92.2% for the annealing at 400 °C for 6 h).

  11. Design and Operation of an Optically-Accessible Modular Reactor for Diagnostics of Thermal Thin Film Deposition Processes.

    Science.gov (United States)

    Kimes, W A; Sperling, B A; Maslars, J E

    2015-01-01

    The design and operation of a simple, optically-accessible modular reactor for probing thermal thin film deposition processes, such as atomic layer deposition processes (ALD) and chemical vapor deposition (CVD), is described. This reactor has a nominal footprint of 225 cm(2) and a mass of approximately 6.6 kg, making it small enough to conveniently function as a modular component of an optical train. The design is simple, making fabrication straightforward and relatively inexpensive. Reactor operation is characterized using two infrared absorption measurements to determine exhaust times for tetrakis(dimethylamino)titanium and water, proto-typical ALD precursors, in a pressure and flow regime commonly used for ALD.

  12. Phase formation, thermal stability and magnetic moment of cobalt nitride thin films

    Directory of Open Access Journals (Sweden)

    Rachana Gupta

    2015-09-01

    Full Text Available Cobalt nitride (Co-N thin films prepared using a reactive magnetron sputtering process are studied in this work. During the thin film deposition process, the relative nitrogen gas flow (RN2 was varied. As RN2 increases, Co(N, Co4N, Co3N and CoN phases are formed. An incremental increase in RN2, after emergence of Co4N phase at RN2 = 10%, results in a linear increase of the lattice constant (a of Co4N. For RN2 = 30%, a maximizes and becomes comparable to its theoretical value. An expansion in a of Co4N, results in an enhancement of the magnetic moment, to the extent that it becomes even larger than pure Co. Such larger than pure metal magnetic moment for tetra-metal nitrides (M4N have been theoretically predicted. Incorporation of N atoms in M4N configuration results in an expansion of a (relative to pure metal and enhances the itinerary of conduction band electrons leading to larger than pure metal magnetic moment for M4N compounds. Though a higher (than pure Fe magnetic moment for Fe4N thin films has been evidenced experimentally, higher (than pure Co magnetic moment is evidenced in this work.

  13. Growth of manganese sulfide (α-MnS) thin films by thermal vacuum evaporation: Structural, morphological and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Hannachi, Amira, E-mail: amira.hannachi88@gmail.com [MALTA-Consolider Team, Institut de Ciència dels Materials – Departamento de Fisica Aplicada, University of Valencia, E-46100 Burjassot, Valencia (Spain); Université de Tunis El-Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie, LR99ES15, 2092 Tunis (Tunisia); Segura, Alfredo [MALTA-Consolider Team, Institut de Ciència dels Materials – Departamento de Fisica Aplicada, University of Valencia, E-46100 Burjassot, Valencia (Spain); Maghraoui-Meherzi, Hager [Université de Tunis El-Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie, LR99ES15, 2092 Tunis (Tunisia)

    2016-09-15

    MnS thin films have been successfully prepared by thermal evaporation method at different substrate temperatures using different masses of MnS powder. The prepared films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and UV–visible spectrophotometry. The XRD measurements show that the films crystallized in the pure α-MnS for substrate temperatures above 100 °C. The optical bandgap of thin films is found to be in the range of 3.2–3.3 eV. A factorial experimental design was used for determining the influence of the two experimental parameters on the films growth. - Highlights: • α-MnS films were deposited on glass and quartz substrates using the thermal evaporation technique. • The effect of substrate temperature on the properties of the MnS films has been studied. • The factorial design was used to determine the most influence parameters.

  14. Effect of Gd3+ Ions on the Thermal Behavior, Optical, Electrical and Magnetic Properties of PbS Thin Films

    Science.gov (United States)

    Ravishankar, S.; Balu, A. R.; Nagarethinam, V. S.

    2018-02-01

    This paper reports the effect of Gd doping concentration on the thermal behavior, structural, morphological, optical, electrical and magnetic properties of PbS thin films. Gd doping concentration in PbS was varied as 0 wt.%, 1 wt.%, 2 wt.%, 3 wt.% and 4 wt.%, respectively. Thermogravimetric-Differential Thermal Analysis curves confirm that both the undoped and doped films become well crystallized above 354°C and 342°C, respectively. X-ray diffraction studies confirm that all the films exhibit face-centered cubic crystal structure with a strong (2 0 0) preferential growth. Undoped films exhibit triangular-shaped grains which modify to small cuboids with Gd doping. Energy dispersive x-ray spectra confirm the presence of Gd in the doped films. Transmission electron microscopy images confirm the presence of nanosized grains for both the undoped and doped films. The doped films showed increased transparency and improved magnetic behaviour. The results obtained confirm that Gd3+, a rare earth ion, strongly influences the physical properties of PbS thin films to a large extent.

  15. Thermal Conductivity of a Nanoscale Yttrium Iron Garnet Thin-Film Prepared by the Sol-Gel Process.

    Science.gov (United States)

    Kim, Yun Young

    2017-08-31

    The thermal conductivity of a nanoscale yttrium iron garnet (Y₃Fe₅O 12 , YIG) thin-film prepared by a sol-gel method was evaluated using the ultrafast pump-probe technique in the present study. The thermoreflectance change on the surface of a 250 nm thick YIG film, induced by the irradiation of femtosecond laser pulses, was measured, and curve fitting of a numerical solution for the transient heat conduction equation to the experimental data was performed using the finite difference method in order to extract the thermal property. Results show that the film's thermal conductivity is 22-83% higher than the properties of bulk YIG materials prepared by different fabrication techniques, reflecting the microstructural characteristics and quality of the film.

  16. Electrical and Optical Properties of GeSi−:H Thin Films Prepared by Thermal Evaporation Method

    Directory of Open Access Journals (Sweden)

    A. A. J. Al-Douri

    2010-01-01

    Full Text Available Thin a-GeSi1−:H films were grown successfully by fabrication of designated ingot followed by evaporation onto glass slides. A range of growth conditions, Ge contents, dopant concentration (Al and As, and substrate temperature, were employed. Stoichiometry of the thin films composition was confirmed using standard surface techniques. The structure of all films was amorphous. Film composition and deposition parameters were investigated for their bearing on film electrical and optical properties. More than one transport mechanism is indicated. It was observed that increasing substrate temperature, Ge contents, and dopant concentration lead to a decrease in the optical energy gap of those films. The role of the deposition conditions on values of the optical constants was determined. Accordingly, models of the density of states for the Ge0.5Si0.5:H thin films as pure, doped with 3.5% of Al (p-type and that doped with 3.5% As (n-type, were proposed.

  17. Investigation of thermal annealing effects on microstructural and optical properties of HfO{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Modreanu, M. [Tyndall National Institute, Cork (Ireland)]. E-mail: mircea.modreanu@tyndall.ie; Sancho-Parramon, J. [Tyndall National Institute, Cork (Ireland); Durand, O. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France); Servet, B. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France); Stchakovsky, M. [Horiba Jobin-Yvon, Thin Film Division, Chilly-Mazarin (France); Eypert, C. [Horiba Jobin-Yvon, Thin Film Division, Chilly-Mazarin (France); Naudin, C. [HORIBA Jobin-Yvon Raman Division, Villeneuve d' Ascq (France); Knowles, A. [HORIBA Jobin-Yvon Ltd., Raman Division, Middlesex (United Kingdom); Bridou, F. [Laboratoire Charles Fabry de l' Institut d' Optique, CNRS, Unite mixte de Recherche 85801, 91403 Orsay Cedex (France); Ravet, M.-F. [Laboratoire Charles Fabry de l' Institut d' Optique, CNRS, Unite mixte de Recherche 85801, 91403 Orsay Cedex (France)

    2006-10-31

    In the present paper, we investigate the effect of thermal annealing on optical and microstructural properties of HfO{sub 2} thin films (from 20 to 190 nm) obtained by plasma ion assisted deposition (PIAD). After deposition, the HfO{sub 2} films were annealed in N{sub 2} ambient for 3 h at 300, 350, 450, 500 and 750 deg. C. Several characterisation techniques including X-ray reflectometry (XRR), X-ray diffraction (XRD), spectroscopic ellipsometry (SE), UV Raman and FTIR were used for the physical characterisation of the as-deposited and annealed HfO{sub 2} thin films. The results indicate that as-deposited PIAD HfO{sub 2} films are mainly amorphous and a transition to a crystalline phase occurs at a temperature higher than 450 deg. C depending on the layer thickness. The crystalline grains consist of cubic and monoclinic phases already classified in literature but this work provides the first evidence of amorphous-cubic phase transition at a temperature as low as 500 deg. C. According to SE, XRR and FTIR results, an increase in the interfacial layer thickness can be observed only for high temperature annealing. The SE results show that the amorphous phase of HfO{sub 2} (in 20 nm thick samples) has an optical bandgap of 5.51 eV. Following its transition to a crystalline phase upon annealing at 750 deg. C, the optical bandgap increases to 5.85 eV.

  18. SERS activity of Ag decorated nanodiamond and nano-β-SiC, diamond-like-carbon and thermally annealed diamond thin film surfaces.

    Science.gov (United States)

    Kuntumalla, Mohan Kumar; Srikanth, Vadali Venkata Satya Siva; Ravulapalli, Satyavathi; Gangadharini, Upender; Ojha, Harish; Desai, Narayana Rao; Bansal, Chandrahas

    2015-09-07

    In the recent past surface enhanced Raman scattering (SERS) based bio-sensing has gained prominence owing to the simplicity and efficiency of the SERS technique. Dedicated and continuous research efforts have been made to develop SERS substrates that are not only stable, durable and reproducible but also facilitate real-time bio-sensing. In this context diamond, β-SiC and diamond-like-carbon (DLC) and other related thin films have been promoted as excellent candidates for bio-technological applications including real time bio-sensing. In this work, SERS activities of nanodiamond, nano-β-SiC, DLC, thermally annealed diamond thin film surfaces were examined. DLC and thermally annealed diamond thin films were found to show SERS activity without any metal nanostructures on their surfaces. The observed SERS activities of the considered surfaces are explained in terms of the electromagnetic enhancement mechanism and charge transfer resonance process.

  19. Thermal activation of nitrogen acceptors in ZnO thin films grown by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Dangbegnon, J.K.; Talla, K.; Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth (South Africa)

    2010-06-15

    Nitrogen doping in ZnO is inhibited by spontaneous formation of compensating defects. Perfect control of the nitrogen doping concentration is required, since a high concentration of nitrogen could induce the formation of donor defects involving nitrogen. In this work, the effect of post-growth annealing in oxygen ambient on ZnO thin films grown by Metalorganic Chemical Vapor Deposition, using NO as both oxidant and nitrogen dopant, is studied. After annealing at 700 C and above, low-temperature photoluminescence shows the appearance of a transition at {proportional_to}3.23 eV which is interpreted as pair emission involving a nitrogen acceptor. A second transition at {proportional_to}3.15 eV is also discussed. This work suggests annealing as a potential means for p-type doping using nitrogen (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. GALVANIC MAGNETIC PROPERTIES OF BISMUTH THIN FILMS DOPED WITH TELLURIUM MADE BY THERMAL VACUUM EVAPORATION

    Directory of Open Access Journals (Sweden)

    V. A. Komarov

    2013-01-01

    Full Text Available The influence of n-type impurity of tellurium (concentration range from 0.005 atomic % Te to 0.15 atomic % Te on galvanic magnetic properties (resistivity, magnetic resistance and Hall constant of Bi thin films with various thicknesses was studied. The properties were measured in temperature range from 77 to 300 K. It was established that the classical size effect in the films is significant and decreases with higher concentration of Te impurity. The analysis of experimental results was carried out in approximation of the law of Jones-Schoenberg dispersion for Bi films doped with tellurium. Calculation of concentration and mobility of charge carriers in the studied films was made.

  1. Optical and Electrical Properties of Ag-Doped In2S3 Thin Films Prepared by Thermal Evaporation

    Directory of Open Access Journals (Sweden)

    Peijie Lin

    2014-01-01

    Full Text Available Ag-doped In2S3 (In2S3:Ag thin films have been deposited onto glass substrates by a thermal evaporation method. Ag concentration is varied from 0 at.% to 4.78 at.%. The structural, optical, and electrical properties are characterized using X-ray diffraction (XRD, spectrophotometer, and Hall measurement system, respectively. The XRD analysis confirms the existence of In2S3 and AgIn5S8 phases. With the increase of the Ag concentration, the band gap of the films is decreased gradually from 2.82 eV to 2.69 eV and the resistivity drastically is decreased from ~103 to 5.478×10-2 Ω·cm.

  2. Polycrystalline-thin-film thermophotovoltaic cells

    Science.gov (United States)

    Dhere, Neelkanth G.

    1996-02-01

    Thermophotovoltaic (TPV) cells convert thermal energy to electricity. Modularity, portability, silent operation, absence of moving parts, reduced air pollution, rapid start-up, high power densities, potentially high conversion efficiencies, choice of a wide range of heat sources employing fossil fuels, biomass, and even solar radiation are key advantages of TPV cells in comparison with fuel cells, thermionic and thermoelectric convertors, and heat engines. The potential applications of TPV systems include: remote electricity supplies, transportation, co-generation, electric-grid independent appliances, and space, aerospace, and military power applications. The range of bandgaps for achieving high conversion efficiencies using low temperature (1000-2000 K) black-body or selective radiators is in the 0.5-0.75 eV range. Present high efficiency convertors are based on single crystalline materials such as In1-xGaxAs, GaSb, and Ga1-xInxSb. Several polycrystalline thin films such as Hg1-xCdxTe, Sn1-xCd2xTe2, and Pb1-xCdxTe, etc., have great potential for economic large-scale applications. A small fraction of the high concentration of charge carriers generated at high fluences effectively saturates the large density of defects in polycrystalline thin films. Photovoltaic conversion efficiencies of polycrystalline thin films and PV solar cells are comparable to single crystalline Si solar cells, e.g., 17.1% for CuIn1-xGaxSe2 and 15.8% for CdTe. The best recombination-state density Nt is in the range of 10-15-10-16 cm-3 acceptable for TPV applications. Higher efficiencies may be achieved because of the higher fluences, possibility of bandgap tailoring, and use of selective emitters such as rare earth oxides (erbia, holmia, yttria) and rare earth-yttrium aluminium garnets. As compared to higher bandgap semiconductors such as CdTe, it is easier to dope the lower bandgap semiconductors. TPV cell development can benefit from the more mature PV solar cell and opto

  3. Thermophoresis and thermal radiation with heat and mass transfer in a magnetohydrodynamic thin-film second-grade fluid of variable properties past a stretching sheet

    Science.gov (United States)

    Khan, Noor Saeed; Gul, Taza; Islam, Saeed; Khan, Waris

    2017-01-01

    The influences of thermophoresis and thermal radiation of a magnetohydrodynamic two-dimensional thin-film second-grade fluid with heat and mass transfer flow in the presence of viscous dissipation past a stretching sheet are analyzed. The main focus of the study is to discuss the significant roll of the fluid variable properties like thermal conductivity and viscosity under the variation of the thin film. The thermal conductivity varies directly as a linear function of temperature showing the property that expresses the ability of a material to transfer heat, and the viscosity is assumed to vary inversely as a linear function of temperature showing that viscous forces become weak at increasing temperature. Thermophoresis occurs to discuss the mass deposition at the surface of the stretching sheet while thermal radiation occurs, especially, at high temperature. The basic governing equations for the velocity, temperature and concentration of the fluid flow have been transformed to high nonlinear coupled differential equations with physical conditions by invoking suitable similarity transformations. The solution of the problem has been obtained by using HAM (Homotopy Analysis Method). The heat and mass transfer flow behaviors are affected significantly by the thin film. The physical influences of thin film parameter and all other parameters have been studied graphically and illustrated. The residual graphs and residual error table elucidate the authentication of the present work.

  4. Research of electrosurgical unit with novel antiadhesion composite thin film for tumor ablation: Microstructural characteristics, thermal conduction properties, and biological behaviors.

    Science.gov (United States)

    Shen, Yun-Dun; Lin, Li-Hsiang; Chiang, Hsi-Jen; Ou, Keng-Liang; Cheng, Han-Yi

    2016-01-01

    The objective of this study was to use surface functionalization to evaluate the antiadhesion property and thermal injury effects on the liver when using a novel electrosurgical unit with nanostructured-doped diamond-like carbon (DLC-Cu) thin films for tumor ablations. The physical and chemical properties of DLC-Cu thin films were characterized by contact angle goniometer, scanning electron microscope, and transmission electron microscope. Three-dimensional (3D) hepatic models were reconstructed using magnetic resonance imaging to simulate a clinical electrosurgical operation. The results indicated a significant increase of the contact angle on the nanostructured DLC-Cu thin films, and the antiadhesion properties were also observed in an animal model. Furthermore, the surgical temperature in the DLC-Cu electrosurgical unit was found to be significantly lower than the untreated unit when analyzed using 3D models and thermal images. In addition, DLC-Cu electrodes caused a relatively small injury area and lateral thermal effect. The results indicated that the nanostructured DLC-Cu thin film coating reduced excessive thermal injury and tissue adherence effect in the liver. © 2015 Wiley Periodicals, Inc.

  5. Thermal conductivity of SrBi.sub.2./sub.Nb.sub.2./sub.O.sub.9./sub. ferroelectric thin films

    Czech Academy of Sciences Publication Activity Database

    Boffoué, M.O.; Jacquot, A.; Duclère, L.-R.; Guilloux-Viry, M.; Hejtmánek, Jiří; Dauscher, A.; Lenoir, B.

    2006-01-01

    Roč. 89, - (2006), 092904/1-092904/3 ISSN 0003-6951 Grant - others:MŠMT, FR(XE) BARRANDE 2005-2006-020-1 Institutional research plan: CEZ:AV0Z10100521 Keywords : thermal conductivity * ferroelectric thin film Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.977, year: 2006

  6. Thermal resistant efficiency of Nb-doped TiO2 thin film based glass window

    Directory of Open Access Journals (Sweden)

    Luu Manh Quynh

    2017-09-01

    Full Text Available The proportional relationship between the infrared (IR transmittance of a transparent material and its IR-induced heat transfer can be explained via a simple model. An agreement between the theory and the experimental work was examined by measuring the temperature rising inside a heat-insulated box with glass windows under IR irradiation, where the material of the glass windows was modified from corning glass (CG to 9 at% Nb-doped TiO2 (TNO fabricated by sputtering deposition. The fabricated TNO thin film was mostly transparent in a visible region and had a low transparency in the IR region, which, in turn, produced the self-cooling effect inside the insulated box. In comparison to the window glass made by CG, the temperature increase inside the box would be 24% less if the window was made by CG coated by TNO (TNO on CG. This suggests the possibility of manufacturing products with desirable features in the energy-cut cooling. The energy-cut was found to decline proportionally to the decrease of the glass window area.

  7. Thermal oxidation of Ni films for p-type thin-film transistors

    KAUST Repository

    Jiang, Jie

    2013-01-01

    p-Type nanocrystal NiO-based thin-film transistors (TFTs) are fabricated by simply oxidizing thin Ni films at temperatures as low as 400 °C. The highest field-effect mobility in a linear region and the current on-off ratio are found to be 5.2 cm2 V-1 s-1 and 2.2 × 103, respectively. X-ray diffraction, transmission electron microscopy and electrical performances of the TFTs with "top contact" and "bottom contact" channels suggest that the upper parts of the Ni films are clearly oxidized. In contrast, the lower parts in contact with the gate dielectric are partially oxidized to form a quasi-discontinuous Ni layer, which does not fully shield the gate electric field, but still conduct the source and drain current. This simple method for producing p-type TFTs may be promising for the next-generation oxide-based electronic applications. © 2013 the Owner Societies.

  8. The W alloying effect on thermal stability and hardening of nanostructured Cu–W alloyed thin films

    Science.gov (United States)

    Zhao, J. T.; Zhang, J. Y.; Hou, Z. Q.; Wu, K.; Feng, X. B.; Liu, G.; Sun, J.

    2018-05-01

    In order to achieve desired mechanical properties of alloys by manipulating grain boundaries (GBs) via solute decoration, it is of great significance to understand the underlying mechanisms of microstructural evolution and plastic deformation. In this work, nanocrystalline (NC) Cu–W alloyed films with W concentrations spanning from 0 to 40 at% were prepared by using magnetron sputtering. Thermal stability (within the temperature range of 200 °C–600 °C) and hardness of the films were investigated by using the x-ray diffraction, transmission electron microscope (TEM) and nanoindentation, respectively. The NC pure Cu film exhibited substantial grain growth upon all annealing temperatures. The Cu–W alloyed films, however, displayed distinct microstructural evolution that depended not only on the W concentration but also on the annealing temperature. At a low temperature of 200 °C, all the Cu–W alloyed films were highly stable, with unconspicuous change in grain sizes. At high temperatures of 400 °C and 600 °C, the microstructural evolution was greatly controlled by the W concentrations. The Cu–W films with low W concentration manifested abnormal grain growth (AGG), while the ones with high W concentrations showed phase separation. TEM observations unveiled that the AGG in the Cu–W alloyed thin films was rationalized by GB migration. Nanoindentation results showed that, although the hardness of both the as-deposited and annealed Cu–W alloyed thin films monotonically increased with W concentrations, a transition from annealing hardening to annealing softening was interestingly observed at the critical W addition of ∼25 at%. It was further revealed that an enhanced GB segregation associated with detwinning was responsible for the annealing hardening, while a reduced solid solution hardening for the annealing softening.

  9. The W alloying effect on thermal stability and hardening of nanostructured Cu-W alloyed thin films.

    Science.gov (United States)

    Zhao, J T; Zhang, J Y; Hou, Z Q; Wu, K; Feng, X B; Liu, G; Sun, J

    2018-05-11

    In order to achieve desired mechanical properties of alloys by manipulating grain boundaries (GBs) via solute decoration, it is of great significance to understand the underlying mechanisms of microstructural evolution and plastic deformation. In this work, nanocrystalline (NC) Cu-W alloyed films with W concentrations spanning from 0 to 40 at% were prepared by using magnetron sputtering. Thermal stability (within the temperature range of 200 °C-600 °C) and hardness of the films were investigated by using the x-ray diffraction, transmission electron microscope (TEM) and nanoindentation, respectively. The NC pure Cu film exhibited substantial grain growth upon all annealing temperatures. The Cu-W alloyed films, however, displayed distinct microstructural evolution that depended not only on the W concentration but also on the annealing temperature. At a low temperature of 200 °C, all the Cu-W alloyed films were highly stable, with unconspicuous change in grain sizes. At high temperatures of 400 °C and 600 °C, the microstructural evolution was greatly controlled by the W concentrations. The Cu-W films with low W concentration manifested abnormal grain growth (AGG), while the ones with high W concentrations showed phase separation. TEM observations unveiled that the AGG in the Cu-W alloyed thin films was rationalized by GB migration. Nanoindentation results showed that, although the hardness of both the as-deposited and annealed Cu-W alloyed thin films monotonically increased with W concentrations, a transition from annealing hardening to annealing softening was interestingly observed at the critical W addition of ∼25 at%. It was further revealed that an enhanced GB segregation associated with detwinning was responsible for the annealing hardening, while a reduced solid solution hardening for the annealing softening.

  10. Structural, morphological, gas sensing and photocatalytic characterization of MoO{sub 3} and WO{sub 3} thin films prepared by the thermal vacuum evaporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Arfaoui, A., E-mail: asma17687@gmail.com [Unité de physique des dispositifs a semi-conducteurs, Faculté des sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia); Touihri, S.; Mhamdi, A. [Unité de physique des dispositifs a semi-conducteurs, Faculté des sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia); Labidi, A. [Unité de Recherche de Physique des Semiconducteurs et Capteurs, IPEST, BP 51, La Marsa, 2070 Tunis (Tunisia); Manoubi, T. [Unité de physique des dispositifs a semi-conducteurs, Faculté des sciences de Tunis, Tunis El Manar University, 2092 Tunis (Tunisia)

    2015-12-01

    Graphical abstract: - Highlights: • Outlining adequacy an original combination of several characterization means. • Structural, morphological and gas sensing properties for both MoO{sub 3} and WO{sub 3} thin films have been studied. • These films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor. • The photocatalytic activity of MoO{sub 3} and WO{sub 3} thin films has been studied. - Abstract: Thin films of molybdenum trioxide and tungsten trioxide were deposited on glass substrates using a simplified thermal evaporation under vacuum method monitored by heat treatment in flowing oxygen at 500 °C for 1 h. The structural and morphological properties of the films were investigated using X-ray diffraction, Raman spectroscopy, atomic force microscopy and scanning electron microscopy. The X-ray diffraction analysis shows that the films of MoO{sub 3} and WO{sub 3} were well crystallized in orthorhombic and monoclinic phase respectively with the crystallites preferentially oriented toward (2 0 0) direction parallel a-axis for both samples. In literature, we have shown in previous papers that structural and surface morphology of metal thin films play an important role in the gas detection mechanism. In this article, we have studied the response evolution of MoO{sub 3} and WO{sub 3} thin films sensors ethanol versus time, working temperature and the concentration of the ethanol. It was found that these films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor. Finally, the photocatalytic activity of the samples was evaluated with respect to the degradation reaction of a wastewater containing methylene blue (MB) under UV–visible light irradiation. The molybdenum trioxide exhibits a higher degradation rate than the tungsten trioxide thin films under similar experimental conditions.

  11. Low thermal budget annealing technique for high performance amorphous In-Ga-ZnO thin film transistors

    Directory of Open Access Journals (Sweden)

    Joong-Won Shin

    2017-07-01

    Full Text Available In this paper, we investigate a low thermal budget post-deposition-annealing (PDA process for amorphous In-Ga-ZnO (a-IGZO oxide semiconductor thin-film-transistors (TFTs. To evaluate the electrical characteristics and reliability of the TFTs after the PDA process, microwave annealing (MWA and rapid thermal annealing (RTA methods were applied, and the results were compared with those of the conventional annealing (CTA method. The a-IGZO TFTs fabricated with as-deposited films exhibited poor electrical characteristics; however, their characteristics were improved by the proposed PDA process. The CTA-treated TFTs had excellent electrical properties and stability, but the CTA method required high temperatures and long processing times. In contrast, the fabricated RTA-treated TFTs benefited from the lower thermal budget due to the short process time; however, they exhibited poor stability. The MWA method uses a low temperature (100 °C and short annealing time (2 min because microwaves transfer energy directly to the substrate, and this method effectively removed the defects in the a-IGZO TFTs. Consequently, they had a higher mobility, higher on-off current ratio, lower hysteresis voltage, lower subthreshold swing, and higher interface trap density than TFTs treated with CTA or RTA, and exhibited excellent stability. Based on these results, low thermal budget MWA is a promising technology for use on various substrates in next generation displays.

  12. The influence of nitrogen and oxygen additions on the thermal characteristics of aluminium-based thin films

    Energy Technology Data Exchange (ETDEWEB)

    Borges, J., E-mail: joelborges@fisica.uminho.pt [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6 (Czech Republic); Macedo, F. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Couto, F.M. [Physics Sciences Laboratory, Norte Fluminense State University, 28013-602 Campos–RJ (Brazil); Rodrigues, M.S.; Lopes, C. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); Pedrosa, P. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Universidade do Porto, Faculdade de Engenharia, Departamento de Engenharia Metalúrgica e de Materiais, Rua Dr. Roberto Frias, s/n, 4200-465 Porto (Portugal); Polcar, T. [Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6 (Czech Republic); Engineering Materials & nCATS, FEE, University of Southampton, Highfield Campus, SO17 1BJ, Southampton (United Kingdom); Marques, L.; Vaz, F. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2015-08-01

    The ternary aluminium oxynitride (AlN{sub x}O{sub y}) system offers the possibility to obtain a wide range of properties by tailoring the ratio between pure Al, AlN{sub x} and AlO{sub y} and therefore opening a significant number of possible applications. In this work the thermal behaviour of AlN{sub x}O{sub y} thin films was analysed by modulated infrared radiometry (MIRR), taking as reference the binary AlO{sub y} and AlN{sub x} systems. MIRR is a non-contact and non-destructive thermal wave measurement technique based on the excitation, propagation and detection of temperature oscillations of very small amplitudes. The intended change of the partial pressure of the reactive gas (N{sub 2} and/or O{sub 2}) influenced the target condition and hence the deposition characteristics which, altogether, affected the composition and microstructure of the films. Based on the MIRR measurements and their qualitative and quantitative interpretation, some correlations between the thermal transport properties of the films and their chemical/physical properties have been found. Furthermore, the potential of such technique applied in this oxynitride system, which present a wide range of different physical responses, is also discussed. The experimental results obtained are consistent with those reported in previous works and show a high potential to fulfil the demands needed for the possible applications of the systems studied. They are clearly indicative of an adequate thermal response if this particular thin film system is aimed to be applied in small sensor devices or in electrodes for biosignal acquisition, such as those for electroencephalography or electromyography as it is the case of the main research area that is being developed in the group. - Highlights: • AlN{sub x}, AlO{sub y} and AlN{sub x}O{sub y} films were deposited by magnetron sputtering. • Discharge characteristics were compared between systems. • Different x and y coefficients were obtained.

  13. Influence of an anomalous dimension effect on thermal instability in amorphous-InGaZnO thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kuan-Hsien; Chou, Wu-Ching, E-mail: tcchang3708@gmail.com, E-mail: wuchingchou@mail.nctu.edu.tw [Department of Electrophysics, National Chiao Tung University, Hsin-chu 300, Taiwan (China); Chang, Ting-Chang, E-mail: tcchang3708@gmail.com, E-mail: wuchingchou@mail.nctu.edu.tw [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Advanced Optoelectronics Technology Center, National Cheng Kung University, Taiwan (China); Chen, Hua-Mao; Tai, Ya-Hsiang [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsin-chu 300, Taiwan (China); Tsai, Ming-Yen; Hung, Pei-Hua; Chu, Ann-Kuo [Department of Photonics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Wu, Ming-Siou; Hung, Yi-Syuan [Department of Electronics Engineering, National Chiao Tung University, Hsin-Chu 300, Taiwan (China); Hsieh, Tien-Yu [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Yeh, Bo-Liang [Advanced Display Technology Research Center, AU Optronics, No.1, Li-Hsin Rd. 2, Hsinchu Science Park, Hsin-Chu 30078, Taiwan (China)

    2014-10-21

    This paper investigates abnormal dimension-dependent thermal instability in amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors. Device dimension should theoretically have no effects on threshold voltage, except for in short channel devices. Unlike short channel drain-induced source barrier lowering effect, threshold voltage increases with increasing drain voltage. Furthermore, for devices with either a relatively large channel width or a short channel length, the output drain current decreases instead of saturating with an increase in drain voltage. Moreover, the wider the channel and the shorter the channel length, the larger the threshold voltage and output on-state current degradation that is observed. Because of the surrounding oxide and other thermal insulating material and the low thermal conductivity of the IGZO layer, the self-heating effect will be pronounced in wider/shorter channel length devices and those with a larger operating drain bias. To further clarify the physical mechanism, fast I{sub D}-V{sub G} and modulated peak/base pulse time I{sub D}-V{sub D} measurements are utilized to demonstrate the self-heating induced anomalous dimension-dependent threshold voltage variation and on-state current degradation.

  14. Thin Film Williamson Nanofluid Flow with Varying Viscosity and Thermal Conductivity on a Time-Dependent Stretching Sheet

    Directory of Open Access Journals (Sweden)

    Waris Khan

    2016-11-01

    Full Text Available This article describes the effect of thermal radiation on the thin film nanofluid flow of a Williamson fluid over an unsteady stretching surface with variable fluid properties. The basic governing equations of continuity, momentum, energy, and concentration are incorporated. The effect of thermal radiation and viscous dissipation terms are included in the energy equation. The energy and concentration fields are also coupled with the effect of Dufour and Soret. The transformations are used to reduce the unsteady equations of velocity, temperature and concentration in the set of nonlinear differential equations and these equations are tackled through the Homotopy Analysis Method (HAM. For the sake of comparison, numerical (ND-Solve Method solutions are also obtained. Special attention has been given to the variable fluid properties’ effects on the flow of a Williamson nanofluid. Finally, the effect of non-dimensional physical parameters like thermal conductivity, Schmidt number, Williamson parameter, Brinkman number, radiation parameter, and Prandtl number has been thoroughly demonstrated and discussed.

  15. Effect of Si additions on thermal stability and the phase transition sequence of sputtered amorphous alumina thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bolvardi, H.; Baben, M. to; Nahif, F.; Music, D., E-mail: music@mch.rwth-aachen.de; Schnabel, V.; Shaha, K. P.; Mráz, S.; Schneider, J. M. [Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, D-52074 Aachen (Germany); Bednarcik, J.; Michalikova, J. [Deutsches Elektronen Synchrotron DESY, FS-PE group, Notkestrasse 85, D-22607 Hamburg (Germany)

    2015-01-14

    Si-alloyed amorphous alumina coatings having a silicon concentration of 0 to 2.7 at. % were deposited by combinatorial reactive pulsed DC magnetron sputtering of Al and Al-Si (90-10 at. %) split segments in Ar/O{sub 2} atmosphere. The effect of Si alloying on thermal stability of the as-deposited amorphous alumina thin films and the phase formation sequence was evaluated by using differential scanning calorimetry and X-ray diffraction. The thermal stability window of the amorphous phase containing 2.7 at. % of Si was increased by more than 100 °C compared to that of the unalloyed phase. A similar retarding effect of Si alloying was also observed for the α-Al{sub 2}O{sub 3} formation temperature, which increased by more than 120 °C. While for the latter retardation, the evidence for the presence of SiO{sub 2} at the grain boundaries was presented previously, this obviously cannot explain the stability enhancement reported here for the amorphous phase. Based on density functional theory molecular dynamics simulations and synchrotron X-ray diffraction experiments for amorphous Al{sub 2}O{sub 3} with and without Si incorporation, we suggest that the experimentally identified enhanced thermal stability of amorphous alumina with addition of Si is due to the formation of shorter and stronger Si–O bonds as compared to Al–O bonds.

  16. Thermal aging effect of vanadyl acetylacetonate precursor for deposition of VO{sub 2} thin films with thermochromic properties

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jung-Hoon [Department of Chemistry, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Nam, Sang-Hun [Institute of Basic Science, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Kim, Donguk; Kim, Minha [School of Electronic and Electrical Engineering, Sungkyunkwan University (Korea, Republic of); Seo, Hyeon Jin; Ro, Yu Hyeon [Department of Chemistry, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Joo, Yong Tae [YOUNG DO Glass Industry Co., Ltd., Jeongeup (Korea, Republic of); Lee, Jaehyeong [School of Electronic and Electrical Engineering, Sungkyunkwan University (Korea, Republic of); Boo, Jin-Hyo, E-mail: jhboo@skku.edu [Department of Chemistry, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of); Institute of Basic Science, Sungkyunkwan University, 440-746 Suwon (Korea, Republic of)

    2016-10-15

    Highlights: • 7 day aged VO(acac){sub 2} sol shows enhanced adhesivity on the SiO{sub 2} compared with non-aged sol. • The aging process has significantly affected the morphologies of VO{sub 2} films. • From the FT-IR spectra, thermal aging process provides the deformation of precursor. • The metal insulator transition (MIT) efficiency (ΔT{sub at2000} {sub nm}) reached a maximum value of 51% at 7 day aging. • Thermal aging process could shorten the aging time of sol solution. - Abstract: Thermochromic properties of vanadium dioxide (VO{sub 2}) have been studied extensively due to their IR reflection applications in energy smart windows. In this paper, we studied the optical switching property of VO{sub 2} thin film, depending on the thermal aging time of the vanadyl acetylacetonate (VO(acac){sub 2}) precursor. We found the alteration of the IR spectra of the precursor by tuning the aging time as well as heat treatments of the precursor. An aging effect of vanadium precursor directly affects the morphologies, optical switching property and crystallinity of VO{sub 2} films. The optimum condition was achieved at the 7 day aging time with metal insulator transition (MIT) efficiency of 50%.

  17. Development of thermal scanning probe microscopy for the determination of thin films thermal conductivity: application to ceramic materials for nuclear industry

    International Nuclear Information System (INIS)

    David, L.

    2006-10-01

    Since the 1980's, various thermal metrologies have been developed to understand and characterize the phenomena of transport of thermal energy at microscopic and submicroscopic scales. Thermal Scanning Probe Microscopy (SThM) is promising. Based on the analysis of the thermal interaction between an heated probe and a sample, it permits to probe the matter at the level of micrometric size in volumes. Performed in the framework of the development of this technique, this work more particularly relates to the study of thin films thermal conductivity. We propose a new modelling of the prediction of measurement with SThM. This model allows not only the calibration of the method for the measurement of bulk material thermal conductivity but also to specify and to better describe the probe - sample thermal coupling and to estimate, from its inversion, thin films thermal conductivity. This new approach of measurement has allowed the determination of the thermal conductivity of micrometric and sub-micrometric thicknesses of meso-porous silicon thin film in particular. Our estimates for the micrometric thicknesses are in agreement with those obtained by the use of Raman spectrometry. For the lower thicknesses of film, we give new data. Our model has, moreover, allowed a better definition of the in-depth resolution of the apparatus. This one is strongly linked to the sensitivity of SThM and strongly depends on the probe-sample thermal coupling area and on the geometry of the probe used. We also developed the technique by the vacuum setting of SThM. Our first results under this environment of measurement are encouraging and validate the description of the coupling used in our model. Our method was applied to the study of ceramics (SiC, TiN, TiC and ZrC) under consideration in the composition of future nuclear fuels. Because of the limitations of SThM in terms of sensitivity to thermal conductivity and in-depth resolution, measurements were also undertaken with a modulated thermo

  18. Thin film processes II

    CERN Document Server

    Kern, Werner

    1991-01-01

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

  19. Properties of NiO nanostructured growth using thermal dry oxidation of nickel metal thin film for hydrogen gas sensing at room temperature

    Science.gov (United States)

    Abubakar, Dauda; Ahmed, Naser M.; Mahmud, Shahrom; Algadri, Natheer A.

    2017-07-01

    A highly qualitative NiO nanostructure was synthesized using thermal dry oxidation of metallic Ni thin films on ITO/glass using the RF sputtering technique. The deposited nickel thin films were oxidized in air ambient at 550 °C inside a furnace. The structural and surface morphologies, and the electrical and gas sensing properties of the NiO nanostructure were examined. An x-ray diffraction analysis demonstrated that the NiO nanostructure has a cubic structure with orientation of the most intense peak at (2 0 0), and shows good crystalline quality. Finite-element scanning electron microscopy and energy dispersive x-ray spectroscopy results revealed O and Ni present in the treated samples, indicating a pure NiO nanostructure composition obtained with high porosity. The electrical properties of the oxidize Ni thin films showed a p-type NiO thin film semiconductor. A hydrogen gas sensing measurement was made at different operating temperatures and different gas concentrations with a detection limit of 30 ppm concentration. The sensor device shows great sensing properties with an excellent sensitivity (310%) at room temperature, which decreases with an increase in the operating temperature. Superfast response and recovery times of 6 and 0.5 s, respectively, were observed with the device at 150 °C operating temperature.

  20. Effect of In Situ Thermal Annealing on Structural, Optical, and Electrical Properties of CdS/CdTe Thin Film Solar Cells Fabricated by Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Alaa Ayad Al-mebir

    2016-01-01

    Full Text Available An in situ thermal annealing process (iTAP has been introduced before the common ex situ cadmium chloride (CdCl2 annealing to improve crystal quality and morphology of the CdTe thin films after pulsed laser deposition of CdS/CdTe heterostructures. A strong correlation between the two annealing processes was observed, leading to a profound effect on the performance of CdS/CdTe thin film solar cells. Atomic force microscopy and Raman spectroscopy show that the iTAP in the optimal processing window produces considerable CdTe grain growth and improves the CdTe crystallinity, which results in significantly improved optoelectronic properties and quantum efficiency of the CdS/CdTe solar cells. A power conversion efficiency of up to 7.0% has been obtained on thin film CdS/CdTe solar cells of absorber thickness as small as 0.75 μm processed with the optimal iTAP at 450°C for 10–20 min. This result illustrates the importance of controlling microstructures of CdTe thin films and iTAP provides a viable approach to achieve such a control.

  1. Rapid thermal annealing of sputter-deposited ZnO:Al films for microcrystalline Si thin-film solar cells

    Directory of Open Access Journals (Sweden)

    Hanajiri T.

    2012-06-01

    Full Text Available Rapid thermal annealing of sputter-deposited ZnO and Al-doped ZnO (AZO films with and without an amorphous silicon (a-Si capping layer was investigated using a radio-frequency (rf argon thermal plasma jet of argon at atmospheric pressure. The resistivity of bare ZnO films on glass decreased from 108 to 104–105 Ω cm at maximum surface temperatures Tmaxs above 650 °C, whereas the resistivity increased from 10-4 to 10-3–10-2Ω cm for bare AZO films. On the other hand, the resistivity of AZO films with a 30-nm-thick a-Si capping layer remained below 10-4Ω cm, even after TPJ annealing at a Tmax of 825 °C. The film crystallization of both AZO and a-Si layers was promoted without the formation of an intermixing layer. Additionally, the crystallization of phosphorous- and boron-doped a-Si layers at the sample surface was promoted, compared to that of intrinsic a-Si under the identical plasma annealing conditions. The TPJ annealing of n+-a-Si/textured AZO was applied for single junction n-i-p microcrystalline Si thin-film solar cells.

  2. Young's Modulus and Coefficient of Linear Thermal Expansion of ZnO Conductive and Transparent Ultra-Thin Films

    Directory of Open Access Journals (Sweden)

    Naoki Yamamoto

    2011-01-01

    Full Text Available A new technique for measuring Young's modulus of an ultra-thin film, with a thickness in the range of about 10 nm, was developed by combining an optical lever technique for measuring the residual stress and X-ray diffraction for measuring the strain in the film. The new technique was applied to analyze the mechanical properties of Ga-doped ZnO (GZO films, that have become the focus of significant attention as a substitute material for indium-tin-oxide transparent electrodes. Young's modulus of the as-deposited GZO films decreased with thickness; the values for 30 nm and 500 nm thick films were 205 GPa and 117 GPa, respectively. The coefficient of linear thermal expansion of the GZO films was measured using the new technique in combination with in-situ residual stress measurement during heat-cycle testing. GZO films with 30–100 nm thickness had a coefficient of linear thermal expansion in the range of 4.3 × 10−6 – 5.6 × 10−6 °C−1.

  3. New Au–Cu–Al thin film shape memory alloys with tunable functional properties and high thermal stability

    International Nuclear Information System (INIS)

    Buenconsejo, Pio John S.; Ludwig, Alfred

    2015-01-01

    An Au–Cu–Al thin film materials library prepared by combinatorial sputter-deposition was characterized by high-throughput experimentation in order to identify and assess new shape memory alloys (SMAs) in this alloy system. Automated resistance measurements during thermal cycling between −20 and 250 °C revealed a wide composition range that undergoes reversible phase transformations with martensite transformation start temperatures, reverse transformation finish temperatures and transformation hysteresis ranging from −15 to 149 °C, 5 to 185 °C and 8 to 60 K, respectively. High-throughput X-ray diffraction analysis of the materials library confirmed that the phase-transforming compositions can be attributed to the existence of the β-AuCuAl parent phase and its martensite product. The formation of large amount of phases based on face-centered cubic (Au–Cu), Al–Cu and Al–Au is responsible for limiting the range of phase-transforming compositions. Selected alloys in this system show excellent thermal cyclic stability of the phase transformation. The functional properties of these alloys, combined with the inherent properties of Au-based alloys, i.e. aesthetic value, oxidation and corrosion resistance, makes them attractive as smart materials for a wide range of applications, including applications as SMAs for elevated temperatures in harsh environment

  4. Room-Temperature Voltage Tunable Phonon Thermal Conductivity via Reconfigurable Interfaces in Ferroelectric Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Ihlefeld, Jon F. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Foley, Brian M. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Mechanical and Aerospace Engineering; Scrymgeour, David A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Michael, Joseph R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); McKenzie, Bonnie B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Medlin, Douglas L. [Sandia National Laboratories, Livermore, CA; Wallace, Margeaux [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering; Trolier-McKinstry, Susan [Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering; Hopkins, Patrick E. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Mechanical and Aerospace Engineering

    2015-02-19

    Dynamic control of thermal transport in solid-state systems is a transformative capability with the promise to propel technologies including phononic logic, thermal management, and energy harvesting. A solid-state solution to rapidly manipulate phonons has escaped the scientific community. Here, we demonstrate active and reversible tuning of thermal conductivity by manipulating the nanoscale ferroelastic domain structure of a Pb(Zr0.3Ti0.7)O3 film with applied electric fields. With subsecond response times, the room-temperature thermal conductivity was modulated by 11%.

  5. X-Ray diffraction analysis of thermally evaporated copper tin selenide thin films at different annealing temperature

    International Nuclear Information System (INIS)

    Mohd Amirul Syafiq Mohd Yunos; Zainal Abidin Talib; Wan Mahmood Mat Yunus; Josephine Liew Ying Chyi; Wilfred Sylvester Paulus

    2010-01-01

    Semiconductor thin films Copper Tin Selenide, Cu 2 SnSe 3 , a potential compound for semiconductor radiation detector or solar cell applications were prepared by thermal evaporation method onto well-cleaned glass substrates. The as-deposited films were annealed in flowing purified nitrogen, N 2 , for 2 hours in the temperature range from 100 to 500 degree Celsius. The structure of as-deposited and annealed films has been studied by X-ray diffraction technique. The semi-quantitative analysis indicated from the Reitveld refinement show that the samples composed of Cu 2 SnSe 3 and SnSe. These studies revealed that the films were structured in mixed phase between cubic space group F-43 m (no. 216) and orthorhombic space group P n m a (no. 62). The crystallite size and lattice strain were determined from Scherrer calculation method. The results show that increasing in annealing temperature resulted in direct increase in crystallite size and decrease in lattice strain. (author)

  6. Rapid Thermal Annealing and Hydrogen Passivation of Polycrystalline Silicon Thin-Film Solar Cells on Low-Temperature Glass

    Directory of Open Access Journals (Sweden)

    Mason L. Terry

    2007-01-01

    Full Text Available The changes in open-circuit voltage (Voc, short-circuit current density (Jsc, and internal quantum efficiency (IQE of aLuminum induced crystallization, ion-assisted deposition (ALICIA polycrystalline silicon thin-film solar cells on low-temperature glass substrates due to rapid thermal anneal (RTA treatment and subsequent remote microwave hydrogen plasma passivation (hydrogenation are examined. Voc improvements from 130 mV to 430 mV, Jsc improvements from 1.2 mA/cm2 to 11.3 mA/cm2, and peak IQE improvements from 16% to > 70% are achieved. A 1-second RTA plateau at 1000°C followed by hydrogenation increases the Jsc by a factor of 5.5. Secondary ion mass spectroscopy measurements are used to determine the concentration profiles of dopants, impurities, and hydrogen. Computer modeling based on simulations of the measured IQE data reveals that the minority carrier lifetime in the absorber region increases by 3 orders of magnitude to about 1 nanosecond (corresponding to a diffusion length of at least 1 μm due to RTA and subsequent hydrogenation. The evaluation of the changes in the quantum efficiency and Voc due to RTA and hydrogenation with computer modeling significantly improves the understanding of the limiting factors to cell performance.

  7. Structural, optical and thermal properties of {beta}-SnS{sub 2} thin films prepared by the spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Khelia, C.; Ben Nasrallah, T.; Amlouk, M.; Belgacem, S. [Faculte des Sciences, Tunis (Tunisia). Lab. de Physique de la Matiere Condensee; Maiz, F. [Equipe de Photothermique de Nabeul, Inst. Preparatoire aux Etudes d' Ingenieur de Nabeul (Tunisia); Mnari, M. [Lab. de Chimie Analytique, Campus Univ., Tunis (Tunisia)

    2000-03-01

    Tin disulfide {beta}-SnS{sub 2} thin films have been prepared on pyrex substrates by the spray pyrolysis technique using tin tetrachloride and thiourea as starting materials. The depositions were carried out in the range of substrate temperatures from 240 to 400 C. Highly c-axis oriented {beta}-SnS{sub 2} films, having a strong (001) X-ray diffraction line are obtained at temperature 280 C and using concentration ratio in solution R = [S]/[Sn] = 2.5. Films surfaces were analyzed by contact atomic force microscopy (AFM) and by scanning electron microscopy (SEM) in order to understand the effect of the deposited temperature on the surface structure. On the other hand, from transmission and reflection spectra, the band gap energy determined is about 2.71 eV. Finally using the photodeflection spectroscopy technique, the thermal conductivity K{sub c} and diffusivity D{sub c} were obtained. Their values are 10 Wm{sup -1}K{sup -1} and 10{sup -5} m{sup 2}s{sup -1} respectively. (orig.)

  8. Microwave properties of MgB{sub 2} thin films prepared in situ by thermal evaporation combined with sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zaitsev, A G; Schneider, R; Hott, R; Ratzel, F; Linker, G; Geerk, J [Forschungszentrum Karlsruhe, Institut fuer Festkoerperphysik, PO Box 3640, D-7602 1 Karlsruhe (Germany)

    2006-06-01

    Superconducting MgB{sub 2} thin films were prepared in situ using a combination of rf magnetron sputtering of B and thermal evaporation of Mg. The films exhibited T{sub c} of up to 36 K. The microwave measurements were performed on 14 x 14 mm{sup 2} films using both Cu-shielded and Nb-shielded sapphire puck resonators at the frequency of 18.8 GHz. The hf surface resistance (R{sub S}) and the change of the hf surface reactance ({delta}X{sub S}) were determined. The films exhibited low R{sub S} matching the literature results for high-quality MgB{sub 2} films. Below 3K R{sub S} reached 3-5 {mu}{omega} which was the resolution limit of our measurement. The temperature dependences of both R{sub S} and {delta}X{sub S} were in good agreement with BCS theory. From the R{sub S}(T) dependence we obtained an energy gap {delta}(0) {approx} 3 meV. The measured variation of the London penetration depth with temperature, {delta}{lambda}{sub L}(T), was also in good agreement with the BCS model. Using the BCS relation between the energy gap and the penetration depth we fitted our experimental {delta}{lambda}{sub L}(T) data and obtained {lambda}{sub L}(0) values, which ranged for different films from 85 to 100 nm.

  9. Determination of the Glass Transition Temperature of Freestanding and Supported Azo-Polymer Thin Films by Thermal Assisted Atomic Force Microscopy

    Directory of Open Access Journals (Sweden)

    Chernykh Elena

    2017-01-01

    Full Text Available In this paper we introduce and apply the method for determination of the glass transition temperature of the sub-100 nm thick freestanding and supported polymer films based on thermally assisted atomic force microscopy (AFM. In proposed approach changes of the phase of an oscillating AFM cantilever are used to determine glass transition temperature. An anomalous decrease of the glass transition temperature for both free-standing and supported azobenzene-functionalized polymer thin films is shown.

  10. In-Situ Testing of the Thermal Diffusivity of Polysilicon Thin Films

    Directory of Open Access Journals (Sweden)

    Yi-Fan Gu

    2016-10-01

    Full Text Available This paper presents an intuitive yet effective in-situ thermal diffusivity testing structure and testing method. The structure consists of two doubly clamped beams with the same width and thickness but different lengths. When the electric current is applied through two terminals of one beam, the beam serves as thermal resistor and the resistance R(t varies as temperature rises. A delicate thermodynamic model considering thermal convection, thermal radiation, and film-to-substrate heat conduction was established for the testing structure. The presented in-situ thermal diffusivity testing structure can be fabricated by various commonly used micro electro mechanical systems (MEMS fabrication methods, i.e., it requires no extra customized processes yet provides electrical input and output interfaces for in-situ testing. Meanwhile, the testing environment and equipment had no stringent restriction, measurements were carried out at normal temperatures and pressures, and the results are relatively accurate.

  11. Thermal tuning of hollow waveguides fabricated by controlled thin-film buckling.

    Science.gov (United States)

    Epp, E; Ponnampalam, N; McMullin, J N; Decorby, R G

    2009-09-28

    We describe the thermal tuning of air-core Bragg waveguides, fabricated by controlled formation of delamination buckles within a multilayer stack of chalcogenide glass and polymer. The upper cladding mirror is a flexible membrane comprising high thermal expansion materials, enabling large tuning of the air-core dimensions for small changes in temperature. Measurements on the temperature dependence of feature heights showed good agreement with theoretical predictions. We applied this mechanism to the thermal tuning of modal cutoff conditions in waveguides with a tapered core profile. Due to the omnidirectional nature of the cladding mirrors, these tapers can be viewed as waveguide-coupled, tunable Fabry-Perot filters.

  12. Thermal spike model interpretation of sputtering yield data for Bi thin films irradiated by MeV {sup 84}Kr{sup 15+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Mammeri, S. [Centre de Recherche Nucléaire d’Alger, B.P. 399, 02 Bd. Frantz Fanon, Alger-gare, Algiers (Algeria); Ouichaoui, S., E-mail: souichaoui@gmail.com [Université des Sciences et de la Technologie H. Boumediene (USTHB), Faculté de Physique, Laboratoire SNIRM, B.P. 32, El-Alia, 16111 Bab Ezzouar, Algiers (Algeria); Ammi, H. [Centre de Recherche Nucléaire d’Alger, B.P. 399, 02 Bd. Frantz Fanon, Alger-gare, Algiers (Algeria); Pineda-Vargas, C.A. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health and Wellness Sciences, CPUT, P.O. Box 1906, Bellville 7535 (South Africa); Dib, A. [Centre de Recherche Nucléaire d’Alger, B.P. 399, 02 Bd. Frantz Fanon, Alger-gare, Algiers (Algeria); Msimanga, M. [iThemba LABS, National Research Foundation, P. Bag 11, Wits 2050, Johannesburg (South Africa); Department of Physics, Tshwane University of Technology, P. Bag X680, Pretoria 001 (South Africa)

    2015-07-01

    A modified thermal spike model initially proposed to account for defect formation in metals within the high heavy ion energy regime is adapted for describing the sputtering of Bi thin films under MeV Kr ions. Surface temperature profiles for both the electronic and atomic subsystems have been carefully evaluated versus the radial distance and time with introducing appropriate values of the Bi target electronic stopping power for multi-charged Kr{sup 15+} heavy ions as well as different target physical proprieties like specific heats and thermal conductivities. Then, the total sputtering yields of the irradiated Bi thin films have been determined from a spatiotemporal integration of the local atomic evaporation rate. Besides, an expected non negligible contribution of elastic nuclear collisions to the Bi target sputtering yields and ion-induced surface effects has also been considered in our calculation. Finally, the latter thermal spike model allowed us to derive numerical sputtering yields in satisfactorily agreement with existing experimental data both over the low and high heavy ion energy regions, respectively, dominated by elastic nuclear collisions and inelastic electronic collisions, in particular with our data taken recently for Bi thin films irradiated by 27.5 MeV Kr{sup 15+} heavy ions. An overall consistency of our model calculation with the predictions of sputtering yield theoretical models within the target nuclear stopping power regime was also pointed out.

  13. Thermal expansion coefficients of obliquely deposited MgF2 thin films and their intrinsic stress.

    Science.gov (United States)

    Jaing, Cheng-Chung

    2011-03-20

    This study elucidates the effects of columnar angles and deposition angles on the thermal expansion coefficients and intrinsic stress behaviors of MgF2 films with columnar microstructures. The behaviors associated with temperature-dependent stresses in the MgF2 films are measured using a phase-shifting Twyman-Green interferometer with a heating stage and the application of a phase reduction algorithm. The thermal expansion coefficients of MgF2 films at various columnar angles were larger than those of glass substrates. The intrinsic stress in the MgF2 films with columnar microstructures was compressive, while the thermal stress was tensile. The thermal expansion coefficients of MgF2 films with columnar microstructures and their intrinsic stress evidently depended on the deposition angle and the columnar angle.

  14. Thin Film Processes

    CERN Document Server

    Vossen, John L.

    1991-01-01

    This sequel to the 1978 classic, Thin Film Processes, gives a clear, practical exposition of important thin film deposition and etching processes that have not yet been adequately reviewed. It discusses selected processes in tutorial overviews with implementation guide lines and an introduction to the literature. Though edited to stand alone, when taken together, Thin Film Processes II and its predecessor present a thorough grounding in modern thin film techniques. Key Features * Provides an all-new sequel to the 1978 classic, Thin Film Processes * Introduces new topics, and several key topics presented in the original volume are updated * Emphasizes practical applications of major thin film deposition and etching processes * Helps readers find the appropriate technology for a particular application

  15. Structural, topographical and magnetic evolution of RF-sputtered Fe-Ni alloy based thin films with thermal annealing

    International Nuclear Information System (INIS)

    Lisha, R; Geetha, P; Anantharaman, M R; Hysen, T; Avasthi, D K; Ramanujan, R V

    2014-01-01

    Metglas 2826 MB having a nominal composition of Fe 40 Ni 38 Mo 4 B 18 is an excellent soft magnetic material and finds application in sensors and memory heads. However, the thin-film forms of Fe 40 Ni 38 Mo 4 B 18 are seldom studied, although they are important in micro-electro-mechanical systems/nano-electro-mechanical systems devices. The stoichiometry of the film plays a vital role in determining the structural and magnetic properties of Fe 40 Ni 38 Mo 4 B 18 thin films: retaining the composition in thin films is a challenge. Thin films of 52 nm thickness were fabricated by RF sputtering technique on silicon substrate from a target of nominal composition of Fe 40 Ni 38 Mo 4 B 18 . The films were annealed at temperatures of 400 °C and 600 °C. The micro-structural studies of films using glancing x-ray diffractometer (GXRD) and transmission electron microscope (TEM) revealed that pristine films are crystalline with (FeNiMo) 23 B 6 phase. Atomic force microscope (AFM) images were subjected to power spectral density analysis to understand the probable surface evolution mechanism during sputtering and annealing. X-ray photoelectron spectroscopy (XPS) was employed to determine the film composition. The sluggish growth of crystallites with annealing is attributed to the presence of molybdenum in the thin film. The observed changes in magnetic properties were correlated with annealing induced structural, compositional and morphological changes. (papers)

  16. Effect of Thermal Cycling on Zinc Antimonide Thin Film Thermoelectric Characteristics

    DEFF Research Database (Denmark)

    Hosseini, Seyed Mojtaba Mir; Rezaniakolaei, Alireza; Rosendahl, Lasse Aistrup

    2017-01-01

    is fixed between a heater block and heat sink cooled by the ambient. The thermoelectric element is studied under open circuit and also optimal constant loads corresponding to maximum power output. The thermal cycles are provided for five different hot junction temperatures, 160, 200, 250, 300 and 350 ᵒC...

  17. Thermal and structural properties of spray pyrolysed CdS thin film

    Indian Academy of Sciences (India)

    Unknown

    probes is not advisable and such measurements are less reliable. But here in photoacoustics, these are avoided and so the results are reliable. The present measurements show that the thermal transport properties are small com- pared to the bulk CdS. This is in conformity with earlier measurements on various other films ...

  18. Thermal processing of thin films using ultra-short laser pulses: applied to photovoltaic materials

    NARCIS (Netherlands)

    Scorticati, D.

    2015-01-01

    In this thesis a novel approach to raise the thermal selectivity of superficial heat treatments, exploiting ultra-short laser pulses, is proposed and studied. That is, the effective applicability of ultrafast lasers for selective heat treatments is proven by increasing the performance of different

  19. High-performance polyamide thin-film composite nanofiltration membrane: Role of thermal treatment

    Science.gov (United States)

    Liu, Baicang; Wang, Shuai; Zhao, Pingju; Liang, Heng; Zhang, Wen; Crittenden, John

    2018-03-01

    Nanofiltration (NF) membranes have many excellent applications (e.g., removing multivalent ions and pretreating water before reverse osmosis, RO), but their relatively high cost limits their application. Especially in recent years, researchers have paid substantial attention to reducing the cost of NF membranes. In this paper, high-performance NF membranes were fabricated using interfacial polymerization (IP) methods. The polymer concentration, IP solution concentration, and thermal treatment conditions were varied. The synthesized membranes were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), a contact angle goniometer, X-ray photoelectron spectroscopy (XPS), attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, and performance tests. The results show that water flux was significantly improved using a hot-water thermal treatment method. Our fabricated thermal-treated NF membrane had an approximately 15% higher water permeability with a value of 13.6 L/(m2 h bar) than that of the commercially available GE HL membrane with a value of 11.8 L/(m2 h bar). Our membranes had the same MgSO4 rejection as that of the GE HL membrane. We found that the thermal treatment causes the NF membrane surface to be smoother and have a high crosslinking degree.

  20. Effect of thermal annealing on properties of polycrystalline ZnO thin films

    Science.gov (United States)

    Gritsenko, L. V.; Abdullin, Kh. A.; Gabdullin, M. T.; Kalkozova, Zh. K.; Kumekov, S. E.; Mukash, Zh. O.; Sazonov, A. Yu.; Terukov, E. I.

    2017-01-01

    Electrical properties (density, carriers mobility, resistivity), optical absorption and photoluminescence spectra of ZnO, grown by MOCVD and hydrothermal methods, have been investigated depending on the annealing and treatment modes in a hydrogen plasma. It has been shown that the electrical and photoluminescent (PL) properties of ZnO are strongly dependent on gas atmosphere during annealing. The annealing in oxygen atmosphere causes a sharp drop of carrier mobility and films conductivity due to the absorption of oxygen on grain boundaries. The process of ZnO electrical properties recovery by the thermal annealing in inert atmosphere (nitrogen), in oil (2×10-2 mbar) and oil-free (1×10-5 mbar) vacuum has been investigated. The hydrogen plasma treatment influence on the intensity of near-band-gap emission (NBE) has been studied. The effect of annealing and subsequent plasma treatment on PL intensity depends on the gas atmosphere of preliminary thermal annealing.

  1. Rapid thermal processing for production of chalcopyrite thin films for solar cells: Design, analysis, and experimental implementation

    Science.gov (United States)

    Lovelett, Robert J.

    The direct conversion of solar energy to electricity, or photovoltaic energy conversion, has a number of environmental, social, and economic advantages over conventional electricity generation from fossil fuels. Currently, the most commonly-used material for photovoltaics is crystalline silicon, which is now produced at large scale and silicon-based devices have achieved power conversion efficiencies over 25% However, alternative materials, such as inorganic thin films, offer a number of advantages including the potential for lower manufacturing costs, higher theoretical efficiencies, and better performance in the field. One of these materials is the chalcopyrite Cu(InGa)(SeS) 2, which has demonstrated module efficiencies over 17% and cell efficiencies over 22%. Cu(InGa)(SeS)2 is now in the early stages of commercialization using a precursor reaction process referred to as a "selenization/sulfization" reaction. The precursor reaction process is promising because it has demonstrated high efficiency along with the large area (approximately 1 m2) uniformity that is required for modules. However, some challenges remain that limit the growth of the chalcopyrite solar cell industry including: slow reactions that limit process throughput, a limited understanding of complex reaction kinetics and transport phenomena that affect the through-film composition, and the use of highly toxic H2Se in the reaction process. In this work, I approach each of these challenges. First, to improve process throughput, I designed and implemented a rapid thermal processing (RTP) reactor, whereby the samples are heated by a 1000 W quartz-halogen lamp that is capable of fast temperature ramps and high temperature dwells. With the reactor in place, however, achieving effective temperature control in the thin film material system is complicated by two intrinsic process characteristics: (i) the temperature of the Cu(InGa)(SeS)2 film cannot be measured directly, which leaves the system without

  2. Rapid thermal annealing of FePt and FePt/Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph

    2011-01-10

    Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

  3. Deposition and thermal characterization of nano-structured aluminum nitride thin film on Cu-W substrate for high power light emitting diode package.

    Science.gov (United States)

    Cho, Hyun Min; Kim, Min-Sun

    2014-08-01

    In this study, we developed AlN thick film on metal substrate for hybrid type LED package such as chip on board (COB) using metal printed circuit board (PCB). Conventional metal PCB uses ceramic-polymer composite as electrical insulating layer. Thermal conductivities of such type dielectric film are typically in the range of 1~4 W/m · K depending on the ceramic filler. Also, Al or Cu alloy are mainly used for metal base for high thermal conduction to dissipate heat from thermal source mounted on metal PCB. Here we used Cu-W alloy with low thermal expansion coefficient as metal substrate to reduce thermal stress between insulating layer and base metal. AlN with polyimide (PI) powder were used as starting materials for deposition. We could obtain very high thermal conductivity of 28.3 W/m · K from deposited AlN-PI thin film by AlN-3 wt% PI powder. We made hybrid type high power LED package using AlN-PI thin film. We tested thermal performance of this film by thermal transient measurement and compared with conventional metal PCB substrate.

  4. Vapor-phase-synthesized fluoroacrylate polymer thin films: thermal stability and structural properties.

    Science.gov (United States)

    Christian, Paul; Coclite, Anna Maria

    2017-01-01

    In this study, the thermal, chemical and structural stability of 1 H ,1 H ,2 H ,2 H -perfluorodecyl acrylate polymers (p-PFDA) synthetized by initiated chemical vapor deposition (iCVD) were investigated. PFDA polymers are known for their interesting crystalline aggregation into a lamellar structure that induces super-hydrophobicity and oleophobicity. Nevertheless, when considering applications which involve chemical, mechanical and thermal stresses, it is important to know the limits under which the crystalline aggregation and the resulting polymer properties are stable. For this, chemical, morphological and structural properties upon multiple heating/cooling cycles were investigated both for linear PFDA polymers and for differently strong cross-linked alterations thereof. Heat treatment leaves the chemical composition of the linear PFDA polymers largely unchanged, while a more ordered crystalline structure with smoother morphology is observed. At the same time, the hydrophobicity and the integrity of the polymer deteriorate upon heating. The integrity and hydrophobicity of cross-linked p-PFDA films was preserved likely because of the lack of internal strain due to the coexistence of both crystalline and amorphous phases. The possibility to finely tune the degree of cross-linking can therefore expand the application portfolio in which PFDA polymers can be utilized.

  5. Enhanced bolometric properties of TiO2-x thin films by thermal annealing

    Science.gov (United States)

    Ashok Kumar Reddy, Y.; Shin, Young Bong; Kang, In-Ku; Lee, Hee Chul; Sreedhara Reddy, P.

    2015-07-01

    The effect of thermal annealing on the bolometric properties of TiO2-x films was investigated. The test-patterned TiO2-x samples were annealed at 300 °C temperature in order to enhance their structural and electrical properties for effective infrared image sensor device applications. The crystallinity was changed from amorphous to rutile/anatase in annealed TiO2-x films. Compared to the as-deposited samples, a decrement of the band gap and a decrease of the electrical resistivity were perceived in annealed samples. We found that the annealed samples show linear current-voltage (I-V) characteristic performance, which implies that ohmic contact was well formed at the interface between the TiO2-x and the Ti electrode. Moreover, the annealed TiO2-x sample had a significantly low 1/f noise parameter (1.21 × 10-13) with a high bolometric parameter (β) value compared to those of the as-deposited samples. As a result, the thermal annealing process can be used to prepare TiO2-x film for a high-performance bolometric device.

  6. Room temperature and thermal decomposition of magnesium hydride/deuteride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ares, J.R.; Leardini, F.; Bodega, J.; Macia, M.D.; Diaz-Chao, P.; Ferrer, I.J.; Fernandez, J.F.; Sanchez, C. [Universidad Autonoma de Madrid (Spain). Lab. de Materiales de Interes en Energias Renovables

    2010-07-01

    Magnesium hydride (MgH{sub 2}) can be considered an interesting material to store hydrogen as long as two main drawbacks were solved: (i) its high stability and (ii) slow (de)hydriding kinetics. In that context, magnesium hydride films are an excellent model system to investigate the influence of structure, morphology and dimensionality on kinetic and thermodynamic properties. In the present work, we show that desorption mechanism of Pd-capped MgH{sub 2} at room temperature is controlled by a bidimensional interphase mechanism and a similar rate step limiting mechanism is observed during thermal decomposition of MgH{sub 2}. This mechanism is different to that occurring in bulk MgH{sub 2} (nucleation and growth) and obtained activation energies are lower than those reported in bulk MgH{sub 2}. We also investigated the Pd-capping properties upon H-absorption/desorption by means of RBS and isotope experiments. (orig.)

  7. Processing of nanocrystalline diamond thin films for thermal management of wide-bandgap semiconductor power electronics

    International Nuclear Information System (INIS)

    Govindaraju, N.; Singh, R.N.

    2011-01-01

    Highlights: → Studied effect of nanocrystalline diamond (NCD) deposition on device metallization. → Deposited NCD on to top of High Electron Mobility Transistors (HEMTs) and Si devices. → Temperatures below 290 deg. C for Si devices and 320 deg. C for HEMTs prevent metal damage. → Development of novel NCD-based thermal management for power electronics feasible. - Abstract: High current densities in wide-bandgap semiconductor electronics operating at high power levels results in significant self-heating of devices, which necessitates the development thermal management technologies to effectively dissipate the generated heat. This paper lays the foundation for the development of such technology by ascertaining process conditions for depositing nanocrystalline diamond (NCD) on AlGaN/GaN High Electron Mobility Transistors (HEMTs) with no visible damage to device metallization. NCD deposition is carried out on Si and GaN HEMTs with Au/Ni metallization. Raman spectroscopy, optical and scanning electron microscopy are used to evaluate the quality of the deposited NCD films. Si device metallization is used as a test bed for developing process conditions for NCD deposition on AlGaN/GaN HEMTs. Results indicate that no visible damage occurs to the device metallization for deposition conditions below 290 deg. C for Si devices and below 320 deg. C for the AlGaN/GaN HEMTs. Possible mechanisms for metallization damage above the deposition temperature are enumerated. Electrical testing of the AlGaN/GaN HEMTs indicates that it is indeed possible to deposit NCD on GaN-based devices with no significant degradation in device performance.

  8. Thin films on cantilevers

    NARCIS (Netherlands)

    Nazeer, H.

    2012-01-01

    The main goal of the work compiled in this thesis is to investigate thin films for integration in micro electromechanical systems (MEMS). The miniaturization of MEMS actuators and sensors without compromising their performance requires thin films of different active materials with specific

  9. An investigation of the insertion of the cations H{sup +}, Na{sup +}, K{sup +} on the electrochromic properties of the thermally evaporated WO{sub 3} thin films grown at different substrate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Patel, K.J. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Kalabhavan, Vadodara 390001, Gujarat (India); Panchal, C.J., E-mail: cjpanchal_msu@yahoo.com [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Kalabhavan, Vadodara 390001, Gujarat (India); Desai, M.S. [Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Kalabhavan, Vadodara 390001, Gujarat (India); Mehta, P.K. [Physics Department, Faculty of Science, M.S. University of Baroda, Vadodara 390002, Gujarat (India)

    2010-11-01

    The phenomenon of electrochromism in tungsten trioxide (WO{sub 3}) thin films has recently attained considerable interest due to their enormous applications in inorganic thin film electrochromic devices. We have investigated the compositional, optical, and electrochromic properties of the WO{sub 3} thin films grown at different substrate temperatures by the thermal evaporation of WO{sub 3} powder. The thin films were characterized using X-ray diffraction (XRD), X-ray photo-emission spectroscopy (XPS), and electrochemical techniques. The XPS analysis suggested that the oxygen to tungsten (O/W) ratio decreases, i.e., the oxygen deficiency increases, on increasing the substrate temperature up to 500 deg. C. The electrochemical analysis provided a comparative study of the coloration efficiency (CE) of the WO{sub 3} thin films intercalated with three different ions viz. H{sup +}, Na{sup +}, and K{sup +}. The effect of the variation of the substrate temperature on the CE and the switching time have also been investigated for the WO{sub 3} thin films intercalated with H{sup +} ions; the thin films deposited at RT and intercalated with H{sup +} ions are found to possess adequate electrochromic properties viz. CE and switching time from device point of view.

  10. Effect of Pre-Annealing on Thermal and Optical Properties of ZnO and Al-ZnO Thin Films

    Science.gov (United States)

    Saravanan, P.; Gnanavelbabu, A.; Pandiaraj, P.

    Zinc oxide (ZnO) nanoparticles were synthesized by a simple solution route method using zinc acetate as the precursor and ethanol as the solvent. At a temperature of 60∘C, a clear homogenous solution is heated to 100∘C for ethanol evaporation. Then the obtained precursor powder is annealed at 600∘C for the formation of ZnO nanocrystalline structure. Doped ZnO particle is also prepared by using aluminum nitrate nonahydrate to produce aluminum (Al)-doped nanoparticles using the same solution route method followed by annealing. Thin film fabrication is done by air evaporation method using the polymer polyvinyl alcohol (PVA). To analyze the optical and thermal properties for undoped and doped ZnO nanocrystalline thin film by precursor annealing, characterizations such as UV, FTIR, AFM, TGA/DTA, XRD, EDAX and Photoluminescence (PL) were also taken. It was evident that precursor annealing had great influence on thermal and optical properties of thin films while ZnO and AZO film showed low crystallinity and intensity than in the powder form. TGA/DTA suggests pre-annealing effect improves the thermal stability, which ensures that Al ZnO nanoparticle can withstand at high temperature too which is the crucial advantage in the semiconductor devices. UV spectroscopy confirmed the presence of ZnO nanoparticles in the thin film by an absorbance peak observed at 359nm with an energy bandgap of 3.4eV. A peak obtained at 301nm with an energy bandgap of 4.12eV shows a blue shift due to the presence of Al-doped ZnO nanoparticles. Both ZnO and AZO bandgap increased due to precursor annealing. In this research, PL spectrum is also studied in order to determine the optical property of the nanoparticle embedded thin film. From PL spectrum, it is observed that the intensity of the doped ZnO is much more enhanced as the dopant concentration is increased to 1wt.% and 2wt.% of Al in ZnO.

  11. Rapid thermal annealing effect on the spatial resistivity distribution of AZO thin films deposited by pulsed-direct-current sputtering for solar cells applications

    Energy Technology Data Exchange (ETDEWEB)

    Ayachi, Boubakeur, E-mail: boubakeur.ayachi@ed.univ-lille1.fr [Institute of Electronics, Microelectronics and Nanotechnology, Lille 1 University, Avenue Poincaré, UMR 8520, CS 60069, Villeneuve d’Ascq 59652 (France); Aviles, Thomas [CROSSLUX, Avenue Georges Vacher, ZI Rousset Peynier, Immeuble CCE, Rousset 13106 (France); Vilcot, Jean-Pierre [Institute of Electronics, Microelectronics and Nanotechnology, Lille 1 University, Avenue Poincaré, UMR 8520, CS 60069, Villeneuve d’Ascq 59652 (France); Sion, Cathy [Institute of Electronics, Microelectronics and Nanotechnology, Lille 1 University, Avenue Poincaré, UMR 8520, CS 60069, Villeneuve d’Ascq 59652 (France); Ecole Centrale Lille, Cité Scientifique – CS20048, Villeneuve d’Ascq 59651 (France)

    2016-03-15

    Graphical abstract: - Highlights: • High quality pulsed-DC sputtered AZO thin films were obtained after RTA treatment. • RTA for 30 s was sufficient to achieve uniform spatial resistivity distribution. • RTA for longer than 1 min showed a small increase in resistivity value. • Such improvement was attributed to grain boundaries passivation and doping activation. • In the framework of low cost solar cells development, RTA process would be helpful. - Abstract: Room temperature deposited aluminium-doped zinc oxide thin films on glass substrate, using pulsed-DC magnetron sputtering, have shown high optical transmittance and low electrical resistivity with high uniformity of its spatial distribution after they were exposed to a rapid thermal annealing process at 400 °C under N{sub 2}H{sub 2} atmosphere. It is particularly interesting to note that such an annealing process of AZO thin films for only 30 s was sufficient, on one hand to improve their optical transmittance from 73% to 86%, on the other hand to both decrease their resistivity from 1.7 × 10{sup −3} Ω cm to 5.1 × 10{sup −4} Ω cm and achieve the highest uniformity spatial distribution. To understand the mechanisms behind such improvements of the optoelectronic properties, electrical, optical, structural and morphological changes as a function of annealing time have been investigated by using hall measurement, UV–visible spectrometry, X-ray diffraction and scanning electron microscope imaging, respectively.

  12. Optical thin film devices

    Science.gov (United States)

    Mao, Shuzheng

    1991-11-01

    Thin film devices are applied to almost all modern scientific instruments, and these devices, especially optical thin film devices, play an essential role in the performances of the instruments, therefore, they are attracting more and more attention. Now there are numerous kinds of thin film devices and their applications are very diversified. The 300-page book, 'Thin Film Device and Applications,' by Prof. K. L. Chopra gives some general ideas, and my paper also outlines the designs, fabrication, and applications of some optical thin film devices made in my laboratory. Optical thin film devices have been greatly developed in the recent decades. Prof. A. Thelan has given a number of papers on the theory and techniques, Prof. H. A. Macleod's book, 'Thin Film Optical Filters,' has concisely concluded the important concepts of optical thin film devices, and Prof. J. A. Dobrowobski has proposed many successful designs for optical thin film devices. Recently, fully-automatic plants make it easier to produce thin film devices with various spectrum requirements, and some companies, such as Balzers, Leybold AG, Satis Vacuum AG, etc., have manufactured such kinds of coating plants for research or mass-production, and the successful example is the production of multilayer antireflection coatings with high stability and reproducibility. Therefore, it could be said that the design of optical thin film devices and coating plants is quite mature. However, we cannot expect that every problem has been solved, the R&D work still continues, the competition still continues, and new design concepts, new techniques, and new film materials are continually developed. Meanwhile, the high-price of fully-automatic coating plants makes unpopular, and automatic design of coating stacks is only the technique for optimizing the manual design according to the physical concepts and experience, in addition, not only the optical system, but also working environment should be taken into account when

  13. Thermal conversion of Cu4O3 into CuO and Cu2O and the electrical properties of magnetron sputtered Cu4O3 thin films

    Science.gov (United States)

    Murali, Dhanya S.; Aryasomayajula, Subrahmanyam

    2018-03-01

    Among the three oxides of copper (CuO, Cu2O, and Cu4O3), Cu4O3 phase (paramelaconite is a natural, and very scarce mineral) is very difficult to synthesize. It contains copper in both + 1 and + 2 valence states, with an average composition Cu2 1+Cu2 2+O3. We have successfully synthesized Cu4O3 phase at room temperature (300 K) by reactive DC magnetron sputtering by controlling the oxygen flow rate (Murali and Subrahmanyam in J Phys D Appl Phys 49:375102, 2016). In the present communication, Cu4O3 thin films are converted to CuO phases by annealing in the air at 680 K and to Cu2O phase when annealed in argon at 720 K; these phase changes are confirmed by temperature-dependent Raman spectroscopy studies. Probably, this is the first report of the conversion of Cu4O3-CuO and Cu2O by thermal annealing. The temperature-dependent (300-200 K) electrical transport properties of Cu4O3 thin films show that the charge transport above 190 K follows Arrhenius-type behavior with activation energy of 0.14 eV. From photo-electron spectroscopy and electrical transport measurements of Cu4O3 thin films, a downward band bending is observed at the surface of the thin film, which shows its p-type semiconducting nature. The successful preparation of phase pure p-type semiconducting Cu4O3 could provide opportunities to further explore its potential applications.

  14. Influence of Yttrium on the Thermal Stability of Ti-Al-N Thin Films

    Directory of Open Access Journals (Sweden)

    Martin Moser

    2010-03-01

    Full Text Available Ti1-xAlxN coated tools are commonly used in high-speed machining, where the cutting edge of an end-mill or insert is exposed to temperatures up to 1100 °C. Here, we investigate the effect of Yttrium addition on the thermal stability of Ti1-xAlxN coatings. Reactive DC magnetron sputtering of powder metallurgically prepared Ti0.50Al0.50, Ti0.49Al0.49Y0.02, and Ti0.46Al0.46Y0.08 targets result in the formation of single-phase cubic (c Ti0.45Al0.55N, binary cubic/wurtzite c/w-Ti0.41Al0.57Y0.02N and singe-phase w-Ti0.38Al0.54Y0.08N coatings. Using pulsed DC reactive magnetron sputtering for the Ti0.49Al0.49Y0.02 target allows preparing single-phase c-Ti0.46Al0.52Y0.02N coatings. By employing thermal analyses in combination with X-ray diffraction and transmission electron microscopy investigations of as deposited and annealed (in He atmosphere samples, we revealed that Y effectively retards the decomposition of the Ti1-x-yAlxYyN solid-solution to higher temperatures and promotes the precipitation of c-TiN, c-YN, and w-AlN. Due to their different microstructure and morphology already in the as deposited state, the hardness of the coatings decreases from ~35 to 22 GPa with increasing Y-content and increasing wurtzite phase fraction. Highest peak hardness of ~38 GPa is obtained for the Y-free c-Ti0.45Al0.55N coating after annealing at Ta = 950 °C, due to spinodal decomposition. After annealing above 1000 °C the highest hardness is obtained for the 2 mol % YN containing c-Ti0.46Al0.52Y0.02N coating with ~29 and 28 GPa for Ta = 1150 and 1200 °C, respectively.

  15. Spatially distributed damage detection in CMC thermal protection materials using thin-film piezoelectric sensors

    Science.gov (United States)

    Kuhr, Samuel J.; Blackshire, James L.; Na, Jeong K.

    2009-03-01

    Thermal protection systems (TPS) of aerospace vehicles are subjected to impacts during in-flight use and vehicle refurbishment. The damage resulting from such impacts can produce localized regions that are unable to resist extreme temperatures. Therefore it is essential to have a reliable method to detect, locate, and quantify the damage occurring from such impacts. The objective of this research is to demonstrate a capability that could lead to detecting, locating and quantifying impact events for ceramic matrix composite (CMC) wrapped tile TPS via sensors embedded in the TPS material. Previous research had shown a correlation between impact energies, material damage state, and polyvinylidene fluoride (PVDF) sensor response for impact energies between 0.07 - 1.00 Joules, where impact events were located directly over the sensor positions1. In this effort, the effectiveness of a sensor array is evaluated for detecting and locating low energy impacts on a CMC wrapped TPS. The sensor array, which is adhered to the internal surface of the TPS tile, is used to detect low energy impact events that occur at different locations. The analysis includes an evaluation of signal amplitude levels, time-of-flight measurements, and signal frequency content. Multiple impacts are performed at each location to study the repeatability of each measurement.

  16. Thermally Stimulated Current and Polarization Fatigue in Pb(Zr,Ti)O3 Thin Films

    Science.gov (United States)

    Okino, Hirotake; Toyoda, Yoshiaki; Shimizu, Masaru; Horiuchi, Toshihisa; Shiosaki, Tadashi; Matsushige, Kazumi

    1998-09-01

    In order to clarify the origin of the polarization fatigue phenomena,charge traps in ferroelectric Pb(Zr,Ti)O3 (PZT) thin filmswere measured using the thermally stimulated current (TSC) technique.For polarization fatigued Pt/PZT/Pt/SiO2/Si(100) capacitors,a peak of TSC was observed, andthe trap density estimated from the TSC dataincreased as switching cycles increased.Activation energy and density of the charge trapswere estimated to be 0.7 0.8 eV andon the order of 1018 cm-3,respectively.It was also observed thatdegradation of remanent polarization of PZTwas improved by the TSC measurement process.On the other hand, no TSC peak was observed forfatigue free Ir/PZT/Ir/IrO2/SiO2/Si(100) capacitors.From these results, it was suggested thatthe main origin of the polarization fatigue phenomenawas the domain pinning caused by trapped charge carriersinjected by polarization reversal.

  17. Thermally activated charge transport in modified tetragonal zirconia thin films prepared by sol-gel method

    Science.gov (United States)

    Aboulkacem, Khiali; Abdelkader, Ammari; Bediaf, Benrabah; Amar, Bouaza; Abdelmalek, Kharoubi; Hadj, Benhebal

    2018-04-01

    Films of Sn-doped ZrO2 were prepared using the sol-gel based dip-coating technique. The X-ray diffraction patterns showed a tetragonal structure with a preferential orientation along the (111) plane. The average grain size of the samples varies from 9.53 to 12.64 nm. Thermal analysis revealed endothermic peaks in the range 84-90 °C and exothermic peaks appearing in the range 489-531 °C. Fourier transform infrared (FTIR) spectra depicted bands located at 612 and 736 cm-1, which are attributed to stretching mode and asymmetric vibrations of Zr-O and O-Zr-O bonds respectively. All films exhibited high transmittance in the visible range above 60% and the optical band gap (E g) decreases from 4.085 to 4.061 eV. The impedance measurements show that the equivalent circuit of the samples is an R p C p where C p is the capacitance of the layer and R p its resistance. The electrical conductivity was found to follows an Arrhenius law with two activation energies.

  18. Negative thermal expansion and magnetocaloric effect in Mn-Co-Ge-In thin films

    Science.gov (United States)

    Liu, Y.; Qiao, K. M.; Zuo, S. L.; Zhang, H. R.; Kuang, H.; Wang, J.; Hu, F. X.; Sun, J. R.; Shen, B. G.

    2018-01-01

    MnCoGe-based alloys with magnetostructural transition show giant negative thermal expansion (NTE) behavior and magnetocaloric effects (MCEs) and thus have attracted a lot of attention. However, the drawback of bad mechanical behavior in these alloys obstructs their practical applications. Here, we report the growth of Mn-Co-Ge-In films with thickness of about 45 nm on (001)-LaAlO3, (001)-SrTiO3, and (001)-Al2O3 substrates. The films grown completely overcome the breakable nature of the alloy and promote its multifunctional applications. The deposited films have a textured structure and retain first-order magnetostructural transition. NTE and MCE behaviors associated with the magnetostructural transition have been studied. The films exhibit a completely repeatable NTE around room temperature. NTE coefficient α can be continuously tuned from the ultra-low expansion (α ˜ -2.0 × 10-7/K) to α ˜ -6.56 × 10-6/K, depending on the growth and particle size of the films on different substrates. Moreover, the films exhibit magnetic entropy changes comparable to the well-known metamagnetic films. All these demonstrate potential multifunctional applications of the present films.

  19. Applying laboratory thermal desorption data in an interstellar context: sublimation of methanol thin films

    Science.gov (United States)

    Green, Simon D.; Bolina, Amandeep S.; Chen, Rui; Collings, Mark P.; Brown, Wendy A.; McCoustra, Martin R. S.

    2009-09-01

    Methods by which experimental measurements of thermal desorption can be applied in astrophysical environments have been developed, using the sublimation of solid methanol as an example. The temperature programmed desorption of methanol from graphitic, amorphous silica and polycrystalline gold substrates was compared, with the kinetic parameters of desorption extracted by either a leading edge analysis or by fitting using a stochastic integration method. At low coverages, the desorption shows a substrate-dependent fractional order. However, at higher coverages methanol desorption is zeroth order with kinetic parameters independent of substrate. Using a kinetic model based on the stochastic integration analyses, desorption under astrophysically relevant conditions can be simulated. We find that the chemical and morphological nature of the substrate has relatively little impact on the desorption temperature of solid methanol, and that the substrate independent zeroth-order kinetics can provide a satisfactory model for desorption in astrophysical environments. Uncertainties in the heating rate and the distribution of grain sizes will have the largest influence on the range of desorption temperature. These conclusions are likely to be generally applicable to all species in dust grain ice mantles. In memory of Rui Chen. E-mail: m.p.collings@hw.ac.uk

  20. Two-stage crossover from thermal to quantum flux creep of dilute vortex ensembles in various high-Tc superconducting thin films

    International Nuclear Information System (INIS)

    Akerman, Johan J.; Venturini, E. L.; Siegal, M. P.; Yun, S. H.; Karlsson, U. O.; Rao, K. V.

    2001-01-01

    The thermal-to-quantum flux creep crossover at low vortex densities has been studied in YBa 2 Cu 3 O 7 , TlBa 2 CaCu 2 O 7-δ , and HgBa 2 CaCu 2 O 6+δ thin films using ac susceptibility. The crossover temperatures T cr are 10--11, 17, and 30 K, respectively. Both thermal and quantum flux creep is suppressed as the vortex density is decreased. We observe a two-stage nature in the crossover behavior which appears to be a general property of all the three materials studied

  1. Thin Film & Deposition Systems (Windows)

    Data.gov (United States)

    Federal Laboratory Consortium — Coating Lab: Contains chambers for growing thin film window coatings. Plasma Applications Coating Lab: Contains chambers for growing thin film window coatings. Solar...

  2. Surface morphology of amorphous germanium thin films following thermal outgassing of SiO{sub 2}/Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Valladares, L. de los Santos, E-mail: ld301@cam.ac.uk [Cavendish Laboratory, Department of Physics, University of Cambridge, J.J. Thomson Ave., Cambridge CB3 0HE (United Kingdom); Dominguez, A. Bustamante [Laboratorio de Cerámicos y Nanomateriales, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Apartado Postal 14-0149, Lima (Peru); Llandro, J.; Holmes, S. [Cavendish Laboratory, Department of Physics, University of Cambridge, J.J. Thomson Ave., Cambridge CB3 0HE (United Kingdom); Quispe, O. Avalos [Laboratorio de Cerámicos y Nanomateriales, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, Apartado Postal 14-0149, Lima (Peru); Langford, R. [Cavendish Laboratory, Department of Physics, University of Cambridge, J.J. Thomson Ave., Cambridge CB3 0HE (United Kingdom); Aguiar, J. Albino [Laboratório de Supercondutividade e Materiais Avançados, Departamento de Física, Universidade Federal de Pernambuco, 50670-901, Recife (Brazil); Barnes, C.H.W. [Cavendish Laboratory, Department of Physics, University of Cambridge, J.J. Thomson Ave., Cambridge CB3 0HE (United Kingdom)

    2014-10-15

    Highlights: • Annealing promotes outgassing of SiO{sub 2}/Si wafers. • Outgassing species embed in the a-Ge film forming bubbles. • The density of bubbles obtained by slow annealing is smaller than by rapid annealing. • The bubbles explode after annealing the samples at 800 °C. • Surface migration at higher temperatures forms polycrystalline GeO{sub 2} islands. - Abstract: In this work we report the surface morphology of amorphous germanium (a-Ge) thin films (140 nm thickness) following thermal outgassing of SiO{sub 2}/Si substrates. The thermal outgassing was performed by annealing the samples in air at different temperatures from 400 to 900 °C. Annealing at 400 °C in slow (2 °C/min) and fast (10 °C/min) modes promotes the formation of bubbles on the surface. A cross sectional view by transmission electron microscope taken of the sample slow annealed at 400 °C reveals traces of gas species embedded in the a-Ge film, allowing us to propose a possible mechanism for the formation of the bubbles. The calculated internal pressure and number of gas molecules for this sample are 30 MPa and 38 × 10{sup 8}, respectively. Over an area of 22 × 10{sup −3} cm{sup 2} the density of bubbles obtained at slow annealing (9 × 10{sup 3} cm{sup −2}) is smaller than that at rapid annealing (6.4 × 10{sup 4} cm{sup −2}), indicating that the amount of liberated gas in both cases is only a fraction of the total gas contained in the substrate. After increasing the annealing temperature in the slow mode, bubbles of different diameters (from tens of nanometers up to tens of micrometers) randomly distribute over the Ge film and they grow with temperature. Vertical diffusion of the outgas species through the film dominates the annealing temperature interval 400–600 °C, whereas coalescence of bubbles caused by lateral diffusion is detected after annealing at 700 °C. The bubbles explode after annealing the samples at 800 °C. Annealing at higher temperatures, such as

  3. Surface morphology of amorphous germanium thin films following thermal outgassing of SiO2/Si substrates

    International Nuclear Information System (INIS)

    Valladares, L. de los Santos; Dominguez, A. Bustamante; Llandro, J.; Holmes, S.; Quispe, O. Avalos; Langford, R.; Aguiar, J. Albino; Barnes, C.H.W.

    2014-01-01

    Highlights: • Annealing promotes outgassing of SiO 2 /Si wafers. • Outgassing species embed in the a-Ge film forming bubbles. • The density of bubbles obtained by slow annealing is smaller than by rapid annealing. • The bubbles explode after annealing the samples at 800 °C. • Surface migration at higher temperatures forms polycrystalline GeO 2 islands. - Abstract: In this work we report the surface morphology of amorphous germanium (a-Ge) thin films (140 nm thickness) following thermal outgassing of SiO 2 /Si substrates. The thermal outgassing was performed by annealing the samples in air at different temperatures from 400 to 900 °C. Annealing at 400 °C in slow (2 °C/min) and fast (10 °C/min) modes promotes the formation of bubbles on the surface. A cross sectional view by transmission electron microscope taken of the sample slow annealed at 400 °C reveals traces of gas species embedded in the a-Ge film, allowing us to propose a possible mechanism for the formation of the bubbles. The calculated internal pressure and number of gas molecules for this sample are 30 MPa and 38 × 10 8 , respectively. Over an area of 22 × 10 −3 cm 2 the density of bubbles obtained at slow annealing (9 × 10 3 cm −2 ) is smaller than that at rapid annealing (6.4 × 10 4 cm −2 ), indicating that the amount of liberated gas in both cases is only a fraction of the total gas contained in the substrate. After increasing the annealing temperature in the slow mode, bubbles of different diameters (from tens of nanometers up to tens of micrometers) randomly distribute over the Ge film and they grow with temperature. Vertical diffusion of the outgas species through the film dominates the annealing temperature interval 400–600 °C, whereas coalescence of bubbles caused by lateral diffusion is detected after annealing at 700 °C. The bubbles explode after annealing the samples at 800 °C. Annealing at higher temperatures, such as 900 °C, leads to surface migration of the

  4. Thin-Film Materials Synthesis and Processing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides a wide capability for deposition and processing of thin films, including sputter and ion-beam deposition, thermal evaporation, electro-deposition,...

  5. Optimization of Processing and Modeling Issues for Thin Film Solar Cell Devices Including Concepts for The Development of Polycrystalline Multijunctions: Annual Report; 24 August 1998-23 August 1999

    Energy Technology Data Exchange (ETDEWEB)

    Birkmire, R.W.; Phillips, J.E.; Shafarman, W.N.; Eser, E.; Hegedus, S.S.; McCandless, B.E. (Institute of Energy Conversion)

    2000-08-25

    This report describes results achieved during phase 1 of a three-phase subcontract to develop and understand thin-film solar cell technology associated to CuInSe{sub 2} and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin films are promising candidates to meet DOE long-range efficiency, reliability, and manufacturing cost goals. The critical issues being addressed under this program are intended to provide the science and engineering basis for the development of viable commercial processes and to improve module performance. The generic research issues addressed are: (1) quantitative analysis of processing steps to provide information for efficient commercial-scale equipment design and operation; (2) device characterization relating the device performance to materials properties and process conditions; (3) development of alloy materials with different bandgaps to allow improved device structures for stability and compatibility with module design; (4) development of improved window/heterojunction layers and contacts to improve device performance and reliability; and (5) evaluation of cell stability with respect to illumination, temperature, and ambient and with respect to device structure and module encapsulation.

  6. Optimization of Processing and Modeling Issues for Thin Film Solar Cell Devices Including Concepts for the Development of Polycrystalline Multijunctions Annual Subcontract Report, 24 August 1999 - 23 August 2000

    Energy Technology Data Exchange (ETDEWEB)

    Birkmire, R. W.; Phillips, J. E.; Shafarman, W. N.; Eser, E.; Hegedus, S. S.; McCandless, B. E.

    2001-11-14

    This report describes the results achieved during Phase I of a three-phase subcontract to develop and understand thin-film solar cell technology associated with CuInSe2 and related alloys, a-Si and its alloys, and CdTe. Modules based on all these thin films are promising candidates to meet DOE long-range efficiency, reliability, and manufacturing cost goals. The critical issues being addressed under this program are intended to provide the science and engineering basis for developing viable commercial processes and to improve module performance. The generic research issues addressed are: (1) quantitative analysis of processing steps to provide information for efficient commercial-scale equipment design and operation; (2) device characterization relating the device performance to materials properties and process conditions; (3) development of alloy materials with different bandgaps to allow improved device structures for stability and compatibility with module design; (4) development of improved window/heterojunction layers and contacts to improve device performance and reliability; and (5) evaluation of cell stability with respect to illumination, temperature, and ambient, and with respect to device structure and module encapsulation.

  7. Optical thin films and coatings from materials to applications

    CERN Document Server

    Flory, Francois

    2013-01-01

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

  8. Thin film hydrogen sensor

    Science.gov (United States)

    Cheng, Yang-Tse; Poli, Andrea A.; Meltser, Mark Alexander

    1999-01-01

    A thin film hydrogen sensor, includes: a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end.

  9. Preparation and thermal volatility characteristics of In2O3/ITO thin film thermocouple by RF magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Yantao Liu

    2017-11-01

    Full Text Available In2O3/ITO thin film thermocouples for high temperature measurement (up to 1250 °C were prepared by radio frequency magnetron sputtering method with different annealing temperatures from 1100 °C to 1250 °C. The changes with microstructure characteristics and the thickness of the thin film thermocouples were investigated as a function of sintering temperature in the range of 1100 °C -1250 °C and annealing time from 2 hrs to 10 hrs at 1200 °C by using XRD and SEM techniques. The thermoelectric output was measured and its results indicated that this thermocouple had a steady and constant voltage output from room temperature to 1247 oC. The thermoelectric voltage and Seebeck coefficient of In2O3/ITO thermocouples measured at 1247 oC were 166.7 mV and 136.3 μV/oC, respectively.

  10. Reflectance improvement by thermal annealing of sputtered Ag/ZnO back reflectors in a-Si:H thin film silicon solar cells

    DEFF Research Database (Denmark)

    Haug, Franz-Josef; Söderström, Karin; Pahud, Céline

    2011-01-01

    Silver can be used as the back contact and reflector in thin film silicon solar cells. When deposited on textured substrates, silver films often exhibit reduced reflectance due to absorption losses by the excitation of surface plasmon resonances. We show that thermal annealing of the silver back...... reflector increases its reflectance drastically. The process is performed at low temperature (150°C) to allow the use of plastic sheets such as polyethylene naphthalate and increases the efficiency of single junction amorphous solar cells dramatically. We present the best result obtained on a flexible...

  11. Comparison of Ultrasonic Welding and Thermal Bonding for the Integration of Thin Film Metal Electrodes in Injection Molded Polymeric Lab-on-Chip Systems for Electrochemistry

    DEFF Research Database (Denmark)

    Matteucci, Marco; Heiskanen, Arto; Zor, Kinga

    2016-01-01

    obtained using TB. Parameters such as metal thickness of electrodes, depth of electrode embedding, delivered power, and height of energy directors (for UW), as well as pressure and temperature (for TB), were systematically studied to evaluate the two bonding methods and requirements for optimal......We compare ultrasonic welding (UW) and thermal bonding (TB) for the integration of embedded thin-film gold electrodes for electrochemical applications in injection molded (IM) microfluidic chips. The UW bonded chips showed a significantly superior electrochemical performance compared to the ones...

  12. Nanomorphology Characteristics of Thermally Annealed Pre Encapsulated P3HT:PCBM Thin Films Using Atomic Force Microscopy

    Science.gov (United States)

    2014-10-30

    blend of electrondonor poly(3-hexylthiophene) ( P3HT ), and electron acceptor phenyl-C61-butyric acid methyl ester (PCBM). The P3HT:PCBM thin films...microscopy (AFM). The active region is composed of a blend of electrondonor poly(3-hexylthiophene) ( P3HT ), and electron acceptor phenyl-C61-butyric acid...achieve a considerable increase in efficiency. Although the driving force that contributes to the aggregation of the P3HT fibril network is not well

  13. Performance Characterization of Monolithic Thin Film Resistors

    Science.gov (United States)

    Yin, Rong

    Thin film resistors have a large resistance range and stable performance under high temperature operating condition. Thin film resistors trimmed by laser beam are able to achieve very high precision on resistance value. As a result, thin film resistors have been widely used to improve the performance of integrated circuits such as operational amplifier, analog-to-digital (A/D) and digital -to-analog (D/A) converters, etc. In this dissertation, a new class of thin film resistors, silicon chrome (SiCr) thin film resistors, has been investigated at length. From thin film characterization to aging behavior modelling, we have carried out a series of engineering activities. The characteristics of the SiCr thin film incorporated into three bipolar processes were first determined. After laser trimming, we have measured a couple of physical parameters of the SiCr film in the heat affected zone (HAZ). This is the first time the sheet resistance and the temperature coefficient of resistance (TCR) of thin film in the HAZ have been characterized. Both thermal and d.c. load accelerated aging tests were performed. The test structures were subjected to the aging for 1000 hours. Based on the test data, we not only evaluated the classical thermal aging model for untrimmed thin film resistors, but also established several empirical thermal aging models for trimmed resistors and d.c. load aging models for both trimmed and untrimmed thin film resistors. All the experiments were carried out for both conventional bar resistors and our new Swiss Cheese (SC) resistors. For the first time, the performance of laser trimmed SC resistors, which was experimentally evaluated, shown a clear superiority over that of trimmed bar resistors. Besides these experiments, we have examined different die attach techniques and their effects on thin film resistors. Also, we have developed a number of hardware systems and software tools, such as a temperature controller, d.c. current source, temperature

  14. Multifunctional thin film surface

    Energy Technology Data Exchange (ETDEWEB)

    Brozik, Susan M.; Harper, Jason C.; Polsky, Ronen; Wheeler, David R.; Arango, Dulce C.; Dirk, Shawn M.

    2015-10-13

    A thin film with multiple binding functionality can be prepared on an electrode surface via consecutive electroreduction of two or more aryl-onium salts with different functional groups. This versatile and simple method for forming multifunctional surfaces provides an effective means for immobilization of diverse molecules at close proximities. The multifunctional thin film has applications in bioelectronics, molecular electronics, clinical diagnostics, and chemical and biological sensing.

  15. Ballistic phonon and thermal radiation transport across a minute vacuum gap in between aluminum and silicon thin films: Effect of laser repetitive pulses on transport characteristics

    Science.gov (United States)

    Yilbas, B. S.; Ali, H.

    2016-08-01

    Short-pulse laser heating of aluminum and silicon thin films pair with presence of a minute vacuum gap in between them is considered and energy transfer across the thin films pair is predicted. The frequency dependent Boltzmann equation is used to predict the phonon intensity distribution along the films pair for three cycles of the repetitive short-pulse laser irradiation on the aluminum film surface. Since the gap size considered is within the Casimir limit, thermal radiation and ballistic phonon contributions to energy transfer across the vacuum gap is incorporated. The laser irradiated field is formulated in line with the Lambert's Beer law and it is considered as the volumetric source in the governing equations of energy transport. In order to assess the phonon intensity distribution in the films pair, equivalent equilibrium temperature is introduced. It is demonstrated that thermal separation of electron and lattice sub-systems in the aluminum film, due to the short-pulse laser irradiation, takes place and electron temperature remains high in the aluminum film while equivalent equilibrium temperature for phonons decays sharply in the close region of the aluminum film interface. This behavior is attributed to the phonon boundary scattering at the interface and the ballistic phonon transfer to the silicon film across the vacuum gap. Energy transfer due to the ballistic phonon contribution is significantly higher than that of the thermal radiation across the vacuum gap.

  16. Effect of thermal annealing on the optical and electronic properties of ZnO thin films grown on p-Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Han, W.G. [Department of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kang, S.G. [Department of Materials Science and Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, T.W. [Advanced Semiconductor Research Center, Division of Electrical and Computer Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)]. E-mail: twk@hanyang.ac.kr; Kim, D.W. [Semiconductor Materials Laboratory, Nano-Device Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of); Cho, W.J. [Semiconductor Materials Laboratory, Nano-Device Research Center, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650 (Korea, Republic of)

    2005-05-30

    The effects of annealing on the optical and the electronics properties of ZnO thin films grown on p-Si(1 0 0) substrates by using radio frequency magnetron sputtering were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS) measurements. The XRD patterns and pole figures showed that the crystallinity of the ZnO films grown on p-Si(1 0 0) substrates was improved by thermal treatment. XRD patterns, pole figures, and TEM images showed that the as-grown and the annealed ZnO films grown on Si(1 0 0) substrates had a c-axis preferential orientation in the [0 0 0 1] crystal direction. The PL spectra showed that luminescence peaks related to the free excitons and the deep levels appeared after annealing. The XPS spectra showed that the peak positions corresponding to the O 1s and the Zn 2p shifted slightly after thermal treatment. These results can help improve understanding of thermal effects on the optical and the electronic properties of ZnO thin films grown on p-Si(1 0 0) substrates.

  17. Enhanced Charge Extraction of Li-Doped TiO2 for Efficient Thermal-Evaporated Sb2S3 Thin Film Solar Cells

    Directory of Open Access Journals (Sweden)

    Chunfeng Lan

    2018-02-01

    Full Text Available We provided a new method to improve the efficiency of Sb2S3 thin film solar cells. The TiO2 electron transport layers were doped by lithium to improve their charge extraction properties for the thermal-evaporated Sb2S3 solar cells. The Mott-Schottky curves suggested a change of energy band and faster charge transport in the Li-doped TiO2 films. Compared with the undoped TiO2, Li-doped mesoporous TiO2 dramatically improved the photo-voltaic performance of the thermal-evaporated Sb2S3 thin film solar cells, with the average power conversion efficiency (PCE increasing from 1.79% to 4.03%, as well as the improved open-voltage (Voc, short-circuit current (Jsc and fill factors. The best device based on Li-doped TiO2 achieved a power conversion efficiency up to 4.42% as well as a Voc of 0.645 V, which are the highest values among the reported thermal-evaporated Sb2S3 solar cells. This study showed that Li-doping on TiO2 can effectively enhance the charge extraction properties of electron transport layers, offering a new strategy to improve the efficiency of Sb2S3-based solar cells.

  18. Enhanced Charge Extraction of Li-Doped TiO₂ for Efficient Thermal-Evaporated Sb₂S₃ Thin Film Solar Cells.

    Science.gov (United States)

    Lan, Chunfeng; Luo, Jingting; Lan, Huabin; Fan, Bo; Peng, Huanxin; Zhao, Jun; Sun, Huibin; Zheng, Zhuanghao; Liang, Guangxing; Fan, Ping

    2018-02-28

    We provided a new method to improve the efficiency of Sb₂S₃ thin film solar cells. The TiO₂ electron transport layers were doped by lithium to improve their charge extraction properties for the thermal-evaporated Sb₂S₃ solar cells. The Mott-Schottky curves suggested a change of energy band and faster charge transport in the Li-doped TiO₂ films. Compared with the undoped TiO₂, Li-doped mesoporous TiO₂ dramatically improved the photo-voltaic performance of the thermal-evaporated Sb₂S₃ thin film solar cells, with the average power conversion efficiency ( PCE ) increasing from 1.79% to 4.03%, as well as the improved open-voltage ( V oc ), short-circuit current ( J sc ) and fill factors. The best device based on Li-doped TiO₂ achieved a power conversion efficiency up to 4.42% as well as a V oc of 0.645 V, which are the highest values among the reported thermal-evaporated Sb₂S₃ solar cells. This study showed that Li-doping on TiO₂ can effectively enhance the charge extraction properties of electron transport layers, offering a new strategy to improve the efficiency of Sb₂S₃-based solar cells.

  19. Control of Nanoplane Orientation in voBN for High Thermal Anisotropy in a Dielectric Thin Film: A New Solution for Thermal Hotspot Mitigation in Electronics.

    Science.gov (United States)

    Cometto, Olivier; Samani, Majid K; Liu, Bo; Sun, Shuangxi; Tsang, Siu Hon; Liu, Johan; Zhou, Kun; Teo, Edwin H T

    2017-03-01

    High anisotropic thermal materials, which allow heat to dissipate in a preferential direction, are of interest as a prospective material for electronics as an effective thermal management solution for hot spots. However, due to their preferential heat propagation in the in-plane direction, the heat spreads laterally instead of vertically. This limitation makes these materials ineffective as the density of hot spots increases. Here, we produce a new dielectric thin film material at room temperature, named vertically ordered nanocrystalline h-BN (voBN). It is produced such that its preferential thermally conductive direction is aligned in the vertical axis, which facilitates direct thermal extraction, thereby addressing the increasing challenge of thermal crosstalk. The uniqueness of voBN comes from its h-BN nanocrystals where all their basal planes are aligned in the direction normal to the substrate plane. Using the 3ω method, we show that voBN exhibits high anisotropic thermal conductivity (TC) with a 16-fold difference between through-film TC and in-plane TC (respectively 4.26 and 0.26 W·m -1 ·K -1 ). Molecular dynamics simulations also concurred with the experimental data, showing that the origin of this anisotropic behavior is due to the nature of voBN's plane ordering. While the consistent vertical ordering provides an uninterrupted and preferred propagation path for phonons in the through-film direction, discontinuity in the lateral direction leads to a reduced in-plane TC. In addition, we also use COMSOL to simulate how the dielectric and thermal properties of voBN enable an increase in hot spot density up to 295% compared with SiO 2 , without any temperature increase.

  20. Effects of O2 plasma post-treatment on ZnO: Ga thin films grown by H2O-thermal ALD

    Science.gov (United States)

    Lee, Yueh-Lin; Chuang, Jia-Hao; Huang, Tzu-Hsuan; Ho, Chong-Long; Wu, Meng-Chyi

    2013-03-01

    Transparent conducting oxides have been widely employed in optoelectronic devices using the various deposition methods such as sputtering, thermal evaporator, and e-gun evaporator technologies.1-3 In this work, gallium doped zinc oxide (ZnO:Ga) thin films were grown on glass substrates via H2O-thermal atomic layer deposition (ALD) at different deposition temperatures. ALD-GZO thin films were constituted as a layer-by-layer structure by stacking zinc oxides and gallium oxides. Diethylzinc (DEZ), triethylgallium (TEG) and H2O were used as zinc, gallium precursors and oxygen source, respectively. Furthermore, we investigated the influences of O2 plasma post-treatment power on the surface morphology, electrical and optical property of ZnO:Ga films. As the result of O2 plasma post-treatment, the characteristics of ZnO:Ga films exhibit a smooth surface, low resistivity, high carrier concentration, and high optical transmittance in the visible spectrum. However, the transmittance decreases with O2 plasma power in the near- and mid-infrared regions.

  1. Effect of Mn content on structural, optical, opto-thermal and electrical properties of ZnO:Mn sprayed thin films compounds

    International Nuclear Information System (INIS)

    Mimouni, R.; Kamoun, O.; Yumak, A.; Mhamdi, A.; Boubaker, K.; Petkova, P.; Amlouk, M.

    2015-01-01

    Highlights: • Proposing an original explanation to the difference between manganese-doped zinc oxide and undoped behavior. • Presenting an original effective electrical and fluorescence-related calculation scheme. • Outlining original AC–DC investigation protocol. - Abstract: Manganese-doped zinc oxide thin films (ZnO:Mn) at different percentages (0–3%) were deposited on glass substrates using a chemical spray technique. The effects of manganese element content on structural, optical, opto-thermal and electrical conductivity of ZnO:Mn thin films were investigated by means of X-ray diffraction, optical measurement, Photoluminescence spectroscopy and impedance spectroscopy. XRD analysis revealed that all films consist of single phase ZnO and were well crystallized in würtzite phase with the crystallites preferentially oriented towards (0 0 2) direction parallel to c-axis. Doping manganese resulted in a slight decrease in the optical band gap energy of the films and a noticeably change in optical constants. The UV peak positions for ZnO:Mn samples slightly red shift to the longer wavelength in comparison with the pure ZnO which can be attributed to the change in the acceptor level induced by the substitutional Mn 2+ and the band-gap narrowing of ZnO with the Mn dopant. We have performed original AC and DC conductivity studies inspired from Jonscher and small polaron models. These studies helped establishing significant correlation between temperature and activation energy and Mn content. From the spectroscopy impedance analysis we investigated the frequency relaxation phenomenon and the circuit equivalent circuit of such thin films. Finally, all results have been discussed, as an objective of the actual work, in terms of the manganese doping concentration

  2. In-situ hybrid study of thermal behaviour of Znsbnd Ni and Znsbnd Nisbnd Al2O3 nanocrystallite thin films induced TEA/MEA by electrocodeposition

    Science.gov (United States)

    Abdulwahab, M.; Fayomi, O. S. I.; Popoola, A. P. I.; Dodo, M. R.

    Our present investigation focuses on the thermal stability of already developed electroforms of Znsbnd Ni and Znsbnd Nisbnd Al2O3 thin films induced with triethylamine (TEA) and monoethylamine (MEA) as surfactant by electrocodeposition on mild steel substrate with the aim to re-examine its micro-hardness and degradation behaviour in static sodium chloride solution. In the event, the samples were thermally treated at 200 °C and air cooled. The results obtained showed that the developed composites are thermally stable with hardness value of the Znsbnd Nisbnd Al2O3 coated; 185 Hv increased to 190.5 Hv indicating a 2.89% improvement. Noticeably, in the Znsbnd Ni coatings, a decrease in the hardness with 26.67% was observed. The oxidation resistance was however favored for both composites.

  3. Enhancing electron mobility in La-doped BaSnO3 thin films by thermal strain to annihilate extended defects

    Science.gov (United States)

    Yu, Sangbae; Yoon, Daseob; Son, Junwoo

    2016-06-01

    We report the enhancement of room-temperature electron mobility in La-doped BaSnO3 (LBSO) thin films with thermal strain induced by high temperature nitrogen (N2) annealing. Simple annealing under an N2 environment consistently doubled the electron mobility of the LBSO films on the SrTiO3 (STO) substrates to as high as 78 cm2 V-1 s-1 at a carrier concentration of 4.0 × 1020 cm-3. This enhancement is mainly attributed to annihilation of extended defects as a consequence of compressive strain induced by the difference in the thermal expansion coefficients of LBSO and STO. Our study suggests that thermal strain can be exploited to reduce extended defects and to facilitate electron transport in transparent oxide semiconductors.

  4. Optical and thermal investigation of GeO2–PbO thin films doped with Au and Ag nanoparticles

    International Nuclear Information System (INIS)

    Carvalho, E.A.; Carmo, A.P.; Bell, M.J.V.; Anjos, V.; Kassab, L.R.P.; Silva, D.M. da

    2012-01-01

    The present work reports on the thermo-optical study of germanate thin films doped with Au and Ag nanoparticles. Transmission Electron Microscopy images, UV–visible absorption and Micro-Raman scattering evidenced the presence of nanoparticles and the formation of collective excitations, the so called surface plasmons. Moreover, the effects of the metallic nanoparticles in the thermal properties of the films were observed. The thermal lens technique was proposed to evaluate the Thermal Diffusivity (D) of the samples. It furnishes superficial spatial resolution of about 100 μm, so it is appropriate to study inhomogeneous samples. It is shown that D may change up to a factor 3 over the surface of a film because of the differences in the nanoparticles concentration distribution.

  5. High-performance thermal sensitive W-doped VO{sub 2}(B) thin film and its identification by first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Dongyun; Xiong, Ping; Chen, Lanli [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Shi, Siqi, E-mail: sqshi@shu.edu.cn [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Ishaq, Ahmad [National Center for Physics, Quaid-I-Azam University, Islamabad 44000 (Pakistan); Luo, Hongjie [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Gao, Yanfeng, E-mail: yfgao@shu.edu.cn [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China)

    2017-03-01

    Graphical abstract: VO{sub 2}(B) thin films with high TCR and suitable resistance were first achieved by W doping. The mechanism for performance improvement was studied by first-principles calculations. The two-dimensional octahedral structure of VO{sub 2}(B) favors the strain control with W-doping for achieving a large TCR, which overcomes the contradiction between the high conductivity and large TCR generated by dopants in VO{sub 2}(M). - Highlights: • High performance W-doped VO{sub 2}(B) thin films were first achieved by co-sputtering. • Mechanism for performance improvement was studied by first-principles calculations. • The two-dimensional octahedral structure of VO{sub 2} (B) favors the strain control. • Achieved VO{sub 2} films possess high thermal sensitivity (TCR: −3.9%/K & R{sub 0}: 32.7 kΩ). - Abstract: VO{sub 2}(B) is currently a preferred phase structure for the application as bolometer material, which, however, suffers from low temperature-coefficient-of-resistance (TCR) values and large resistances. Here we present the combined experimental and first-principles calculations study on both doped and undoped VO{sub 2}(B) thin films enabling us to attain high TCR (−3.9%/k) and suitable square-resistance (32.7 kΩ) by controlled W doping employing the widely used magnetron sputtering technique. The TCR value is 50% larger than reported ones at the similar resistance. The underlying microscopic mechanism for the performance improvement was studied and results indicated that the introduction of extra electrons and the variation in the band structure resulting from the incorporation of W{sup 6+} ions in the VO{sub 2}(B) crystal lattice contribute to the enhancement of the electronic conductivity. Moreover, the special two-dimensional octahedral structure of monoclinic (C2/m) B-phase VO{sub 2} favors the strain control with W-doping for achieving a large TCR, which overcomes the analogous predicament between the high conductivity and large TCR

  6. Potential of thin-film solar cell module technology

    Science.gov (United States)

    Shimada, K.; Ferber, R. R.; Costogue, E. N.

    1985-01-01

    During the past five years, thin-film cell technology has made remarkable progress as a potential alternative to crystalline silicon cell technology. The efficiency of a single-junction thin-film cell, which is the most promising for use in flat-plate modules, is now in the range of 11 percent with 1-sq cm cells consisting of amorphous silicon, CuInSe2 or CdTe materials. Cell efficiencies higher than 18 percent, suitable for 15 percent-efficient flat plate modules, would require a multijunction configuration such as the CdTe/CuInSe2 and tandem amorphous-silicon (a-Si) alloy cells. Assessments are presented of the technology status of thin-film-cell module research and the potential of achieving the higher efficiencies required for large-scale penetration into the photovoltaic (PV) energy market.

  7. Photocatalytic Activity and Stability of Porous Polycrystalline ZnO Thin-Films Grown via a Two-Step Thermal Oxidation Process

    Directory of Open Access Journals (Sweden)

    James C. Moore

    2014-08-01

    Full Text Available The photocatalytic activity and stability of thin, polycrystalline ZnO films was studied. The oxidative degradation of organic compounds at the ZnO surface results from the ultraviolet (UV photo-induced creation of highly oxidizing holes and reducing electrons, which combine with surface water to form hydroxyl radicals and reactive oxygen species. Therefore, the efficiency of the electron-hole pair formation is of critical importance for self-cleaning and antimicrobial applications with these metal-oxide catalyst systems. In this study, ZnO thin films were fabricated on sapphire substrates via direct current sputter deposition of Zn-metal films followed by thermal oxidation at several annealing temperatures (300–1200 °C. Due to the ease with which they can be recovered, stabilized films are preferable to nanoparticles or colloidal suspensions for some applications. Characterization of the resulting ZnO thin films through atomic force microscopy and photoluminescence indicated that decreasing annealing temperature leads to smaller crystal grain size and increased UV excitonic emission. The photocatalytic activities were characterized by UV-visible absorption measurements of Rhodamine B dye concentrations. The films oxidized at lower annealing temperatures exhibited higher photocatalytic activity, which is attributed to the increased optical quality. Photocatalytic activity was also found to depend on film thickness, with lower activity observed for thinner films. Decreasing activity with use was found to be the result of decreasing film thickness due to surface etching.

  8. Non-Stoichiometric Amorphous Indium Selenide Thin Films as a Buffer Layer for CIGS Solar Cells with Various Temperatures in Rapid Thermal Annealing.

    Science.gov (United States)

    Yoo, Myoung Han; Kim, Nam-Hoon

    2016-05-01

    The conventional structure of most of copper indium gallium diselenide (Culn(1-x)Ga(x)Se2, CIGS) solar cells includes a CdS thin film as a buffer layer. Cd-free buffer layers have attracted great interest for use in photovoltaic applications to avoid the use of hazardous and toxic materials. The RF magnetron sputtering method was used with an InSe2 compound target to prepare the indium selenide precursor. Rapid thermal annealing (RTA) was conducted in ambient N2 gas to control the concentration of volatile Se from the precursor with a change in temperature. The nature of the RTA-treated indium selenide thin films remained amorphous under annealing temperatures of ≤ 700 degrees C. The Se concentration of the RTA-treated specimens demonstrated an opposite trend to the annealing temperature. The optical transmittance and band gap energies were 75.33% and 2.451-3.085 eV, respectively, and thus were suitable for the buffer layer. As the annealing temperature increased, the resistivity decreased by an order-of-magnitude from 10(4) to 10(1) Ω-cm. At lower Se concentrations, the conductivity abruptly changed from p-type to n-type without crystallite formation in the amorphous phase, with the carrier concentration in the order of 10(17) cm(-3).

  9. Fabrication of a Cu(InGaSe2 Thin Film Photovoltaic Absorber by Rapid Thermal Annealing of CuGa/In Precursors Coated with a Se Layer

    Directory of Open Access Journals (Sweden)

    Chun-Yao Hsu

    2013-01-01

    Full Text Available Cu(InGaSe2 (CIGS thin film absorbers are prepared using sputtering and selenization processes. The CuGa/In precursors are selenized during rapid thermal annealing (RTA, by the deposition of a Se layer on them. This work investigates the effect of the Cu content in precursors on the structural and electrical properties of the absorber. Using X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy, and Hall effect measurement, it is found that the CIGS thin films produced exhibit facetted grains and a single chalcopyrite phase with a preferred orientation along the (1 1 2 plane. A Cu-poor precursor with a Cu/( ratio of 0.75 demonstrates a higher resistance, due to an increase in the grain boundary scattering and a reduced carrier lifetime. A Cu-rich precursor with a Cu/( ratio of 1.15 exhibits an inappropriate second phase ( in the absorber. However, the precursor with a Cu/( ratio of 0.95 exhibits larger grains and lower resistance, which is suitable for its application to solar cells. The deposition of this precursor on Mo-coated soda lime glass substrate and further RTA causes the formation of a MoSe2 layer at the interface of the Mo and CIGS.

  10. On the role of tin doping in InOx thin films deposited by radio frequency-plasma enhanced reactive thermal evaporation.

    Science.gov (United States)

    Amaral, A; Brogueira, P; Lavareda, G; de Carvalho, C Nunes

    2010-04-01

    In view of the increasing need for larger-area display devices with improved image quality it becomes increasingly important to decrease resistivity while maintaining transparency in transparent conducting oxides (TCOs). Accomplishing the goal of increased conductivity and transparency will require a deeper understanding of the relationships between the structure and the electro-optical properties of these materials. In this work we study the role of tin doping in InOx thin films. Undoped indium oxide (InOx) and indium tin oxide (ITO) thin films were deposited at room temperature by radiofrequency plasma enhanced reactive thermal evaporation (rf-PERTE), a new technique recently developed in our laboratory using as evaporation source either In rods or a 90%In:10%Sn alloy, respectively. The two most important macroscopic properties-optical transparency and electrical resistivity-seem to be independent of the tin content in these deposition conditions. Results show that the films present a visible transmittance of the order of 82%, and an electrical resistivity of about 8 x 10(-4) omega x cm. Surface morphology characterization made by atomic force microscopy (AFM) showed that homogeneity of the films deposited from a 90%In:10%Sn alloy is enhanced (a film with small and compact grains is produced) and consequently a smooth surface with reduced roughness and with similar grain size and shape is obtained. Films deposited from pure In rods evaporation source show the presence of aggregates randomly distributed above a film tissue formed of thinner grains.

  11. Two-stage crossover from thermal to quantum flux creep of dilute vortex ensembles in various high-T{sub c} superconducting thin films

    Energy Technology Data Exchange (ETDEWEB)

    Akerman, Johan J.; Venturini, E. L.; Siegal, M. P.; Yun, S. H.; Karlsson, U. O.; Rao, K. V.

    2001-09-01

    The thermal-to-quantum flux creep crossover at low vortex densities has been studied in YBa{sub 2}Cu{sub 3}O{sub 7}, TlBa{sub 2}CaCu{sub 2}O{sub 7-{delta}}, and HgBa{sub 2}CaCu{sub 2}O{sub 6+{delta}} thin films using ac susceptibility. The crossover temperatures T{sub cr} are 10--11, 17, and 30 K, respectively. Both thermal and quantum flux creep is suppressed as the vortex density is decreased. We observe a two-stage nature in the crossover behavior which appears to be a general property of all the three materials studied.

  12. Thin Film Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Zweibel, K.

    1998-11-19

    The motivation to develop thin film technologies dates back to the inception of photovoltaics. It is an idea based on achieving truly low-cost photovoltaics appropriate for mass production and energy significant markets. The key to the idea is the use of pennies worth of active materials. Since sunlight carries relatively little energy in comparison with combustion-based energy sources, photovoltaic (PV) modules must be cheap to produce energy that can be competitive. Thin films are presumed to be the answer to that low-cost requirement. But how cheap do they have to be? The following is an oversimplified analysis that allows some insight into this question.

  13. Thin film solar energy collector

    Science.gov (United States)

    Aykan, Kamran; Farrauto, Robert J.; Jefferson, Clinton F.; Lanam, Richard D.

    1983-11-22

    A multi-layer solar energy collector of improved stability comprising: (1) a substrate of quartz, silicate glass, stainless steel or aluminum-containing ferritic alloy; (2) a solar absorptive layer comprising silver, copper oxide, rhodium/rhodium oxide and 0-15% by weight of platinum; (3) an interlayer comprising silver or silver/platinum; and (4) an optional external anti-reflective coating, plus a method for preparing a thermally stable multi-layered solar collector, in which the absorptive layer is undercoated with a thin film of silver or silver/platinum to obtain an improved conductor-dielectric tandem.

  14. Laser thermoreflectance for semiconductor thin films metrology

    Science.gov (United States)

    Gailly, P.; Hastanin, J.; Duterte, C.; Hernandez, Y.; Lecourt, J.-B.; Kupisiewicz, A.; Martin, P.-E.; Fleury-Frenette, K.

    2012-06-01

    We present a thermoreflectance-based metrology concept applied to compound semiconductor thin films off-line characterization in the solar cells scribing process. The presented thermoreflectance setup has been used to evaluate the thermal diffusivity of thin CdTe films and to measure eventual changes in the thermal properties of 5 μm CdTe films ablated by nano and picosecond laser pulses. The temperature response of the CdTe thin film to the nanosecond heating pulse has been numerically investigated using the finite-difference time-domain (FDTD) method. The computational and experimental results have been compared.

  15. Spectral-optical-electrical-thermal properties of deposited thin films of nano-sized calcium(II)-8-hydroxy-5,7-dinitroquinolate complex.

    Science.gov (United States)

    Farag, A A M; Haggag, Sawsan M S; Mahmoud, Mohamed E

    2011-11-01

    Spectral-optical-electrical-thermal properties of deposited thin films of nano-sized calcium(II)-8-hydroxy-5,7-dinitroquinolate complex, Ca[((NO(2))(2)-8HQ)(2)], were explored, studied and evaluated in this work. Thin films of Ca[((NO(2))(2)-8HQ)(2)] were assembled by using a direct, simple and efficient layer-by-layer (LBL) chemical deposition technique. The optical properties of thin films were investigated by using spectrophotometric measurements of transmittance and reflectance at normal incidence in the wavelength range 200-2500 nm. The refractive index, n, and the absorption index, k, of Ca[((NO(2))(2)-8HQ)(2)] films were determined from the measured transmittance and reflectance. The real and imaginary dielectric constants were also determined. The analysis of the spectral behavior of the absorption coefficient in the intrinsic absorption region reveals a direct allowed transition with band gaps of 1.1 eV and 2.4 eV for the optical and transport energy gaps, respectively. The current-voltage characteristics of Ca[((NO(2))(2)-8HQ)(2)] showed a trap-charge limited conduction in determining the current at the intermediate and high bias regimes. Graphical representation of the current-voltage characteristics yields three distinct linear parts indicating the existence of three conduction mechanisms. Structural characterization and identification were confirmed by using Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy (SEM) was also used to image the surface morphology of the deposited nano-sized metal complex and such study revealed a high homogeneity in surface spherical particle distribution with average particles size in the range 20-40 nm. Thermal gravimetric analysis (TGA) was also studied for [(NO(2))(2)-8HQ] and Ca[((NO(2))(2)-8HQ)(2)] to evaluate and confirm the thermal stability characteristics incorporated into the synthesized nano-sized Ca[((NO(2))(2)-8HQ)(2)] complex. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Review of US Nanocorp - SNL Joint Development of Thermal-Sprayed Thin-Film Cathodes for Thermal Batteries

    Energy Technology Data Exchange (ETDEWEB)

    GUIDOTTI,RONALD A.; REINHARDT,FREDERICK W.; DAI,JINXIANG; XIAO,T. DANNY; REISNER,DAVID E.

    2000-11-14

    The use of plasma spray to deposit thin metal-sulfide cathode films is described in this paper. Conventional electroactive stack components in thermal batteries are constructed from pressed-powder parts that are difficult to fabricate in large diameters in thicknesses <0.010. Plasma-sprayed electrodes do not steer from this difficulty, allowing greater energy densities and specific energies to be realized. Various co-spraying agents have been found suitable for improving the mechanical as well as electrochemical properties of plasma-sprayed cathodes for thermal batteries. These electrodes generally show equal or improved performance over conventional pressed-powder electrodes. A number of areas for future growth and development of plasma-spray technology is discussed.

  17. Study of annealing effects in Al–Sb bilayer thin films

    Indian Academy of Sciences (India)

    Abstract. In this paper, we present preparation and characterization of Al–Sb bilayer thin films. Thin films of thicknesses, 3000/1000 Ц and 3000/1500 Е, were obtained by the thermal evaporation (resistive heating) method. Vacuum annealing and rapid thermal annealing methods were used to mix bilayer thin film structure.

  18. Study of annealing effects in Al–Sb bilayer thin films

    Indian Academy of Sciences (India)

    Keywords. AlSb; thin film; RBS; optical band gap. Abstract. In this paper, we present preparation and characterization of Al–Sb bilayer thin films. Thin films of thicknesses, 3000/1000 Å and 3000/1500 Å, were obtained by the thermal evaporation (resistive heating) method. Vacuum annealing and rapid thermal annealing ...

  19. Thin film metal-oxides

    CERN Document Server

    Ramanathan, Shriram

    2009-01-01

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

  20. Magnetohydrodynamic thin film and heat transfer of power law fluids over an unsteady stretching sheet with variable thermal conductivity

    Directory of Open Access Journals (Sweden)

    Lin Yanhai

    2016-01-01

    Full Text Available This paper presents an investigation on the MHD thin film flow and heat transfer of a power law fluid over an unsteady stretching sheet. The effects of power law viscosity on a temperature field are taken into account with a modified Fourier’s law Proposed by Zheng by assuming that the temperature field is similar to the velocity field. The governing equations are reduced to a system of nonlinear ordinary differential equations. The numerical solutions are obtained by using the shooting method coupled with the Runge-Kutta method. The influence of the Hartmann number, the power law exponent, the unsteadiness parameter, the thickness parameter and the generalized Prandtl number on the velocity and temperature fields are presented graphically and analyzed. Moreover, the critical formula for parameters are derived which indicated that the magnetic field has no effect on the critical value.

  1. Post-deposition thermal treatment of sprayed ZnO:Al thin films for enhancing the conductivity

    Science.gov (United States)

    Devasia, Sebin; Athma, P. V.; Shaji, Manu; Kumar, M. C. Santhosh; Anila, E. I.

    2018-03-01

    Here, we report the enhanced conductivity of Aluminium doped (2at.%) zinc oxide thin films prepared by simple spray pyrolysis technique. The structural, optical, electrical, morphological and compositional investigations confirm the better quality of films that can be a potential candidate for application in transparent electronics. Most importantly, the film demonstrates an average transmittance of 90 percent with a low resistivity value which was dropped from 1.39 × 10-2 to 5.10 × 10-3 Ω .cm, after annealing, and a very high carrier concentration in the order of 10 × 20cm-3. Further, we have used the Swanepoel envelop method to calculate thickness, refractive index and extinction coefficient from the interference patterns observed in the transmission spectra. The calculated figure of merit of the as-deposited sample was 1.4 × 10-3Ω-1 which was improved to 2.5 × 10-3Ω-1 after annealing.

  2. Measurement of Out-of-Plane Thermal Conductivity of Epitaxial YBa2Cu3O_{7-{δ }} Thin Films in the Temperature Range from 10 K to 300 K by Photothermal Reflectance

    Science.gov (United States)

    Murakami, Yusuke; Goto, Haruna; Taguchi, Yoshihiro; Nagasaka, Yuji

    2017-10-01

    We measured the out-of-plane ( c-axis) thermal conductivity of epitaxially grown YBa2Cu3O_{7-{δ }} (YBCO) thin films (250 nm, 500 nm and 1000 nm) in the temperature range from 10 K to 300 K using the photothermal reflectance technique. The technique enables us to determine the thermal conductivity perpendicular to a thin film on a substrate by curve fitting analysis of the phase lag between the thermoreflectance signal and modulated heating laser beam in the frequency range from 102 Hz to 106 Hz. The uncertainties of measured thermal conductivity of all samples were estimated to be within {± }9 % at 300 K, {± }12 % at 180 K, {± }16 % at 90 K and {± }20 % below 50 K. The experimental results show that the thermal conductivity is dependent on the thickness of the thin films across the entire temperature range. We also observed that the thermal conductivity of the present YBCO thin films showed T^{1.4} to T^{1.6} glass-like dependence below 50 K, even though the films are crystalline solids. In order to explain the reason for this temperature dependence, we attempted to analyze our results using phonon relaxation times for possible phonon scattering models, including stacking faults, grain boundary and tunneling states scattering models.

  3. Epitaxial thin films

    Science.gov (United States)

    Hunt, Andrew Tye; Deshpande, Girish; Lin, Wen-Yi; Jan, Tzyy-Jiuan

    2006-04-25

    Epitatial thin films for use as buffer layers for high temperature superconductors, electrolytes in solid oxide fuel cells (SOFC), gas separation membranes or dielectric material in electronic devices, are disclosed. By using CCVD, CACVD or any other suitable deposition process, epitaxial films having pore-free, ideal grain boundaries, and dense structure can be formed. Several different types of materials are disclosed for use as buffer layers in high temperature superconductors. In addition, the use of epitaxial thin films for electrolytes and electrode formation in SOFCs results in densification for pore-free and ideal gain boundary/interface microstructure. Gas separation membranes for the production of oxygen and hydrogen are also disclosed. These semipermeable membranes are formed by high-quality, dense, gas-tight, pinhole free sub-micro scale layers of mixed-conducting oxides on porous ceramic substrates. Epitaxial thin films as dielectric material in capacitors are also taught herein. Capacitors are utilized according to their capacitance values which are dependent on their physical structure and dielectric permittivity. The epitaxial thin films of the current invention form low-loss dielectric layers with extremely high permittivity. This high permittivity allows for the formation of capacitors that can have their capacitance adjusted by applying a DC bias between their electrodes.

  4. Protein thin film machines.

    Science.gov (United States)

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

    2010-12-01

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

  5. Preparation and properties of thin films treatise on materials science and technology

    CERN Document Server

    Tu, K N

    1982-01-01

    Treatise on Materials Science and Technology, Volume 24: Preparation and Properties of Thin Films covers the progress made in the preparation of thin films and the corresponding study of their properties. The book discusses the preparation and property correlations in thin film; the variation of microstructure of thin films; and the molecular beam epitaxy of superlattices in thin film. The text also describes the epitaxial growth of silicon structures (thermal-, laser-, and electron-beam-induced); the characterization of grain boundaries in bicrystalline thin films; and the mechanical properti

  6. Oriented growth of thin films of samarium oxide by MOCVD

    Indian Academy of Sciences (India)

    Unknown

    Infrared spectroscopic study reveals that films grown above 600°C are free of carbon. Keywords. MOCVD; thin films .... Simultaneous thermogravimetry and differential thermal analysis (TG/DTA) of the complex was carried ..... quality thin films of rare earth oxides by MOCVD, using the phenanthroline adducts of pentadionate ...

  7. Comparison of Ultrasonic Welding and Thermal Bonding for the Integration of Thin Film Metal Electrodes in Injection Molded Polymeric Lab-on-Chip Systems for Electrochemistry

    Directory of Open Access Journals (Sweden)

    Marco Matteucci

    2016-10-01

    Full Text Available We compare ultrasonic welding (UW and thermal bonding (TB for the integration of embedded thin-film gold electrodes for electrochemical applications in injection molded (IM microfluidic chips. The UW bonded chips showed a significantly superior electrochemical performance compared to the ones obtained using TB. Parameters such as metal thickness of electrodes, depth of electrode embedding, delivered power, and height of energy directors (for UW, as well as pressure and temperature (for TB, were systematically studied to evaluate the two bonding methods and requirements for optimal electrochemical performance. The presented technology is intended for easy and effective integration of polymeric Lab-on-Chip systems to encourage their use in research, commercialization and education.

  8. Measurement of thermal conductance of La0.7Sr0.3MnO3 thin films deposited on SrTiO3 and MgO substrates

    Science.gov (United States)

    Aryan, A.; Guillet, B.; Routoure, J. M.; Fur, C.; Langlois, P.; Méchin, L.

    2015-01-01

    We present measurements of the thermal conductance of thin-film-on-substrate structures that could serve as thin film uncooled bolometers. Studied samples were 75 nm thick epitaxial La0.7Sr0.3MnO3 thin films deposited on SrTiO3 (0 0 1) and MgO (0 0 1) substrates patterned in square geometries of areas ranging from 50 μm × 50 μm to 200 μm × 200 μm. The model allows estimating thermal boundary conductance values at the interface between film and substrate of 0.28 ± 0.08 × 106 W K-1 m-2 for LSMO/STO (0 0 1) and 5.8 ± 3.0 × 106 W K-1 m-2 for LSMO/MgO (0 0 1) from measurements performed in the static regime. Analytical expressions of thermal conductance and thermal capacitance versus modulation frequency are compared to measurements of the elevation temperature due to absorbed incoming optical power. The overall good agreement found between measurements and model finally provides the possibility to calculate the bolometric response of thin film bolometers, thus predicting their frequency response for various geometries.

  9. Growth of carbon nanofiber coatings on nickel thin films on fused silica by catalytic thermal chemical vapor deposition: On the use of titanium, titanium-tungsten and tantalum as adhesion layers

    NARCIS (Netherlands)

    Thakur, D.B.; Tiggelaar, Roald M.; Gardeniers, Johannes G.E.; Lefferts, Leonardus; Seshan, Kulathuiyer

    2009-01-01

    Coatings of carbon nanofiber (CNF) layers were synthesized on fused silica substrates using a catalytic thermal chemical vapor deposition process (C-TCVD). The effects of various adhesion layers–titanium, titanium–tungsten and tantalum–under the nickel thin film on the attachment of carbon

  10. 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.

  11. Influence of the substrate temperature on the structural, optical, and electrical properties of tin selenide thin films deposited by thermal evaporation method

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N.; Sharma, V.; Padha, N. [Department of Physics and Electronics, Dr. Ambedkar Road, University of Jammu, Jammu-180 006, Jammu and Kashmir State (India); Shah, N.M.; Desai, M.S.; Panchal, C.J. [Applied Physics Department, Faculty of Technology and Engineering, M. S. University of Baroda, Vadodara-390 001, Gujarat State (India); Protsenko, I.Yu. [Appl. Physics Dept., Faculty of Electronic and Information Technologies, Sumy State University (Ukraine)

    2010-01-15

    Thin films of tin selenide (SnSe) were deposited on sodalime glass substrates, which were held at different temperatures in the range of 350-550 K, from the pulverized compound material using thermal evaporation method. The effect of substrate temperature (T{sub s}) on the structural, morphological, optical, and electrical properties of the films were investigated using x-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission measurements, and Hall-effect characterization techniques. The temperature dependence of the resistance of the films was also studied in the temperature range of 80-330 K. The XRD spectra and the SEM image analyses suggest that the polycrystalline thin films having uniform distribution of grains along the (111) diffraction plane was obtained at all T{sub s}. With the increase of T{sub s} the intensity of the diffraction peaks increased and well-resolved peaks at 550 K, substrate temperature, were obtained. The analysis of the data of the optical transmission spectra suggests that the films had energy band gap in the range of 1.38-1.18 eV. Hall-effect measurements revealed the resistivity of films in the range 112-20 {omega} cm for films deposited at different T{sub s}. The activation energy for films deposited at different T{sub s} was in the range of 0.14 eV-0.28 eV as derived from the analysis of the data of low-temperature resistivity measurements. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Functional organic thin films

    OpenAIRE

    Scharnberg, Michael

    2007-01-01

    Organic thin films are used in many technological and engineering applications nowadays. They find use as coatings, sensors, detectors, as matrix materials in nanocomposites, as self-assembled monolayers for surface functionalization, as low-k dielectrics in integrated circuits and in advanced organic electronic applications like organic light emitting diodes, organic field effect transistors and organic photovoltaics (esp. organic solar cells) and many other applications. OLED displays are n...

  13. Thin film processes

    CERN Document Server

    Vossen, John L

    1978-01-01

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

  14. Synthesis and electrical characterization of low-temperature thermal-cured epoxy resin/functionalized silica hybrid-thin films for application as gate dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Na, Moonkyong, E-mail: nmk@keri.re.kr [HVDC Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); System on Chip Chemical Process Research Center, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 790-784 (Korea, Republic of); Kang, Young Taec [Creative and Fundamental Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); Department of Polymer Science and Engineering, Pusan National University, Busan, 609-735 (Korea, Republic of); Kim, Sang Cheol [HVDC Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of); Kim, Eun Dong [Creative and Fundamental Research Division, Korea Electrotechnology Research Institute, Changwon, 642-120 (Korea, Republic of)

    2013-07-31

    Thermal-cured hybrid materials were synthesized from homogenous hybrid sols of epoxy resins and organoalkoxysilane-functionalized silica. The chemical structures of raw materials and obtained hybrid materials were characterized using Fourier transform infrared spectroscopy. The thermal resistance of the hybrids was enhanced by hybridization. The interaction between epoxy matrix and the silica particles, which caused hydrogen bonding and van der Waals force was strengthened by organoalkoxysilane. The degradation temperature of the hybrids was improved by approximately 30 °C over that of the parent epoxy material. The hybrid materials were formed into uniformly coated thin films of about 50 nm-thick using a spin coater. An optimum mixing ratio was used to form smooth-surfaced hybrid films. The electrical property of the hybrid film was characterized, and the leakage current was found to be well below 10{sup −6} A cm{sup −2}. - Highlights: • Preparation of thermal-curable hybrid materials using epoxy resin and silica. • The thermal stability was enhanced through hybridization. • The insulation property of hybrid film was investigated as gate dielectrics.

  15. Sb{sub 7}Te{sub 3}/ZnSb multilayer thin films for high thermal stability and long data retention phase-change memory

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shiyu; Wu, Weihua [Functional Materials Research Laboratory, School of Materials Science & Engineering, Tongji University, Shanghai 201804 (China); Zhai, Jiwei, E-mail: apzhai@tongji.edu.cn [Functional Materials Research Laboratory, School of Materials Science & Engineering, Tongji University, Shanghai 201804 (China); Song, Sannian; Song, Zhitang [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Science, Shanghai 200050 (China)

    2017-04-15

    Highlights: • Sb{sub 7}Te{sub 3} (ST) provides a fast crystallization speed, low melting temperature. • The Sb{sub 7}Te{sub 3}/ZnSb films exhibits faster crystallization speed, high thermal stability. • The calculated temperature for 10-year data retention is about 127 {sup o}C. • The Sb{sub 7}Te{sub 3}/ZnSb multilayer configuration with low power consumption. - Abstract: Phase-change memory is regard as one of the most promising candidates for the next-generation non-volatile memory. In this work, we proposed a Sb{sub 7}Te{sub 3}/ZnSb multilayer thin films to improve the thermal stability of Sb-rich Sb{sub 3}Te{sub 7}. The sheet resistance ratio between amorphous and crystalline states reached up to 4 orders of magnitude. With regard to the thermal stability, the calculated temperature for 10-year data retention is about 127 °C. The threshold current and threshold voltage of a cell based on Sb{sub 7}Te{sub 3}/ZnSb are 6.9 μA and 1.9 V, respectively. The lower RESET power is presented in the PCM cells of Sb{sub 7}Te{sub 3}/ZnSb films, benefiting from its high resistivity.

  16. Glassy dynamics and heterogeneity of polymer thin films

    International Nuclear Information System (INIS)

    Kanaya, Toshiji; Inoue, Rintaro; Kawashima, Kazuko; Miyazaki, Tsukasa; Matsuba, Go; Nishida, Koji; Tsukushi, Itaru; Shibata, Kaoru; Hino, Masahiro

    2009-01-01

    We review our recent studies on glassy dynamics and glass transition of polymer thin films using neutron and X-ray reflectivity and inelastic neutron techniques. In the last decade extensive studies have been performed on polymer thin films to reveal very interesting but unusual properties such as reduction in the glass transition temperature T g with film thickness and negative thermal expansivity for thin films below about 25 nm, and often some contradictory experimental results have been reported. It is believed that a key to solve the controversial situation is to disclose heterogeneous structure or multi-layer structure in polymer thin films. In the review, therefore, we summarize our recent experimental results by neutron and X-ray reflectivity and inelastic neutron scattering, focusing on the dynamic heterogeneity in polymer thin films. (author)

  17. Microstructure and optical response optimization of Ge/Si quantum dots transformed from the sputtering-grown Ge thin film by manipulating the thermal annealing.

    Science.gov (United States)

    Shu, Qijiang; Wang, Rongfei; Yang, Jie; Zhang, Mingling; Zeng, Tianjian; Sun, Tao; Wang, Chong; Yang, Yu

    2018-03-02

    A series of zero-dimensional Ge/Si quantum dots (QDs) samples are fabricated by inducing the transformation from the two-dimensional Ge thin film, which is grown by the traditional direct current (DC) magnetron sputtering, via regulating the annealing process. The QD density increases sharply after the post rapid thermal annealing (PRTA). The observations of atomic force microscopy (AFM) and Raman spectroscopy suggest that the good morphology of Ge QDs results from an appropriate thermodynamics and kinetics surrounding shaped by the cooperative interaction of the Ge-Si lattice mismatch, the film's surface temperature, and the difference in thermal expansion coefficients between Ge and Si. The photoluminescence (PL) peaks of Ge QDs are detected in monolayer Ge QDs with ultrahigh density at 17 K. The Metal-Ge/Si QDs-Metal (MGM) photodetector fabricated from the ultrahigh-density QDs sample exhibits a relatively high current gain, absolute photoelectric responsivity, and internal quantum efficiency (IQE). Our results demonstrate that the high-quality Ge QDs with strong light absorption and quantum confinement effect can be realized by modulating DC magnetron sputtering and the PRTA process. This paves the way for realizing silicon-based optoelectronic devices with high performance by the traditional, relatively low-cost, and large-scale production nanomaterial fabricating method.

  18. Carbon thin film thermometry

    Science.gov (United States)

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

    1973-01-01

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

  19. Synthesis, structure and optical properties of thin films form GeS2-In2S3 system deposited by thermal co-evaporation

    Czech Academy of Sciences Publication Activity Database

    Todorov, R.; Petkov, K.; Kincl, Miloslav; Černošková, E.; Vlček, Milan; Tichý, Ladislav

    2014-01-01

    Roč. 558, 2 May (2014), s. 298-305 ISSN 0040-6090 Institutional support: RVO:61389013 Keywords : chalcogenide glass es * thin films * optical properties Subject RIV: CA - Inorganic Chemistry Impact factor: 1.759, year: 2014

  20. Status of High Performance PV: Polycrystalline Thin-Film Tandems

    Energy Technology Data Exchange (ETDEWEB)

    Symko-Davies, M.

    2005-02-01

    The High-Performance Photovoltaic (HiPerf PV) Project was initiated by the U.S. Department of Energy to substantially increase the viability of photovoltaics (PV) for cost-competitive applications so that PV can contribute significantly to our energy supply and our environment. The HiPerf PV Project aims at exploring the ultimate performance limits of existing PV technologies, approximately doubling their sunlight-to-electricity conversion efficiencies during its course. This work includes bringing thin-film cells and modules toward 25% and 20% efficiencies, respectively, and developing multijunction concentrator cells and modules able to convert more than one-third of the sun's energy to electricity (i.e., 33% efficiency). This paper will address recent accomplishments of the NREL in-house research effort involving polycrystalline thin-film tandems, as well as the research efforts under way in the subcontracted area.

  1. Properties of a-SiGe Thin Films on Glass by Co-Sputtering for Photovoltaic Absorber Application.

    Science.gov (United States)

    Shahahmadi, S A; Yeganeh, B; Huda, N; Asim, N; Hafidz, M; Alam, M M; Alothman, Z A; Sopian, K; Amin, N

    2015-11-01

    Non-hydrogenated amorphous Silicon-Germanium (a-SiGe) thin films were deposited at two different base pressures by RF magnetron co-sputtering. Moreover, an ex-situ thermal annealing was carried out to investigate the material properties to be suitable as the bottom cell of multi-junction solar cells. Compositional study of the films using EDX showed Ge-rich thin films with 75 atomic% of Ge. XRD reflection study implied that all samples were entirely amorphous in nature. However, a significant improvement of morphology possibly due to low base pressure was observed while thermal annealing caused peening and reduction of surface inhomogeneity in both as-sputtered films. UV-VIS-IR analysis confirmed the FESEM results. The highest transmittance was observed in the as-deposited sample grown at 4 x 10(-5) Torr, which however reduced after thermal annealing. Tauc's model was implied for band gap determination and band gap energy as low as 1.07 eV was found in the annealed sample grown at lower base pressure (4 x 10(-6) Torr). Electrical properties of films were investigated by Hall effect measurement system and results found the reduction of resistivity with the same trend of optical band gap energy.

  2. Phonon thermal conductivity of scandium nitride for thermoelectrics from first-principles calculations and thin-film growth

    Science.gov (United States)

    Kerdsongpanya, Sit; Hellman, Olle; Sun, Bo; Koh, Yee Kan; Lu, Jun; Van Nong, Ngo; Simak, Sergei I.; Alling, Björn; Eklund, Per

    2017-11-01

    The knowledge of lattice thermal conductivity of materials under realistic conditions is vitally important since many modern technologies require either high or low thermal conductivity. Here, we propose a theoretical model for determining lattice thermal conductivity, which takes into account the effect of microstructure. It is based on ab initio description that includes the temperature dependence of the interatomic force constants and treats anharmonic lattice vibrations. We choose ScN as a model system, comparing the computational predictions to the experimental data by time-domain thermoreflectance. Our experimental results show a trend of reduction in lattice thermal conductivity with decreasing domain size predicted by the theoretical model. These results suggest a possibility to control thermal conductivity by microstructural tailoring and provide a predictive tool for the effect of the microstructure on the lattice thermal conductivity of materials based on ab initio calculations.

  3. Effects of Rapid Thermal Annealing on the Structural, Electrical, and Optical Properties of Zr-Doped ZnO Thin Films Grown by Atomic Layer Deposition

    Directory of Open Access Journals (Sweden)

    Jingjin Wu

    2016-08-01

    Full Text Available The 4 at. % zirconium-doped zinc oxide (ZnO:Zr films grown by atomic layer deposition (ALD were annealed at various temperatures ranging from 350 to 950 °C. The structural, electrical, and optical properties of rapid thermal annealing (RTA treated ZnO:Zr films have been evaluated to find out the stability limit. It was found that the grain size increased at 350 °C and decreased between 350 and 850 °C, while creeping up again at 850 °C. UV–vis characterization shows that the optical band gap shifts towards larger wavelengths. The Hall measurement shows that the resistivity almost keeps constant at low annealing temperatures, and increases rapidly after treatment at 750 °C due to the effect of both the carrier concentration and the Hall mobility. The best annealing temperature is found in the range of 350–550 °C. The ZnO:Zr film-coated glass substrates show good optical and electrical performance up to 550 °C during superstrate thin film solar cell deposition.

  4. The effect of thermal annealing on the optical band gap of cadmium sulphide thin films, prepared by the chemical bath deposition technique

    International Nuclear Information System (INIS)

    Ampong, F. K.; Boakye, F.; Asare Donkor, N. K.

    2010-01-01

    Cadmium sulphide thin films have been prepared by the chemical bath deposition technique (ph 11, 70 degree centigrade). Two different sets of films were prepared under varied conditions and concentrations of their ions sources (Cd 2+ from cadmium nitrate, S 2- from thiourea) and Na 2 EDTA as a complexing agent. A UV mini-Schimazu UV-VIS Spectrophotometer was used to determine the optical absorbance of the films as a function of wavelength at room temperature over the wavelength range 200 - 600 nm. The samples were then thermally annealed for thirty minutes, at temperatures of 100 degree centigrade, and 200 degree centigrade, after which the absorbance of the films were again recorded. The band gap values obtained for the sample with 0.5 M CdS as deposited, annealed at 100 degree centigrade and 200 degree centigrade were 2.1 eV, 2.2 eV and 2.3 eV respectively. Whilst the values obtained for the sample 0.15 CdS as deposited, annealed at 100 degree centigrade and annealed at 200 degree centigrade were 2.0 eV, 2.01 eV and 2.02 eV respectively. The increase in band gap with annealing temperature might be attributed to the improvement in crystallinity in the films. (au)

  5. Effects of Rapid Thermal Annealing on the Structural, Electrical, and Optical Properties of Zr-Doped ZnO Thin Films Grown by Atomic Layer Deposition.

    Science.gov (United States)

    Wu, Jingjin; Zhao, Yinchao; Zhao, Ce Zhou; Yang, Li; Lu, Qifeng; Zhang, Qian; Smith, Jeremy; Zhao, Yongming

    2016-08-13

    The 4 at. % zirconium-doped zinc oxide (ZnO:Zr) films grown by atomic layer deposition (ALD) were annealed at various temperatures ranging from 350 to 950 °C. The structural, electrical, and optical properties of rapid thermal annealing (RTA) treated ZnO:Zr films have been evaluated to find out the stability limit. It was found that the grain size increased at 350 °C and decreased between 350 and 850 °C, while creeping up again at 850 °C. UV-vis characterization shows that the optical band gap shifts towards larger wavelengths. The Hall measurement shows that the resistivity almost keeps constant at low annealing temperatures, and increases rapidly after treatment at 750 °C due to the effect of both the carrier concentration and the Hall mobility. The best annealing temperature is found in the range of 350-550 °C. The ZnO:Zr film-coated glass substrates show good optical and electrical performance up to 550 °C during superstrate thin film solar cell deposition.

  6. Thin-film solar cell

    NARCIS (Netherlands)

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

    1998-01-01

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

  7. Cu2ZnGeS4 thin films deposited by thermal evaporation: the impact of Ge concentration on physical properties

    Science.gov (United States)

    Courel, Maykel; Sanchez, T. G.; Mathews, N. R.; Mathew, X.

    2018-03-01

    In this work, the processing of Cu2ZnGeS4 (CZGS) thin films by a thermal evaporation technique starting from CuS, GeS and ZnS precursors, and post-deposition thermal processing, is discussed. Batches of films with GeS layers of varying thicknesses are deposited in order to study the role of Ge concentration on the structural, morphological, optical and electrical properties of CZGS films. The formation of the CZGS compound with a tetragonal phase and a kesterite structure is confirmed for all samples using XRD and Raman studies. An improvement in crystallite size for Ge-poor films is also observed in the XRD analysis, which is in good agreement with the grain size observed in the cross section SEM image. Furthermore, it is found that the band-gap of CZGS film can be tailored in the range of 2.0–2.23 eV by varying Ge concentration. A comprehensive electrical characterization is also performed which demonstrates that slightly Ge-poor samples are described by the lowest grain boundary defect densities and the highest photosensitivity and mobility values. A study of the work function of CZGS samples with different Ge concentrations is also presented. Finally, a theoretical evaluation is presented, considering, under ideal conditions, the possible impact of these films on device performance. Based on the characterization results, it is concluded that Ge-poor CZGS samples deposited by thermal evaporation present better physical properties for device applications.

  8. Ferromagnetic thin films

    Science.gov (United States)

    Krishnan, Kannan M.

    1994-01-01

    A ferromagnetic .delta.-Mn.sub.1-x Ga.sub.x thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of .delta.-Mn.sub.1-x Ga.sub.x overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of .delta.-Mn.sub.1-x Ga.sub.x and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4 .+-.0.05.

  9. Portable low-power thermal cycler with dual thin-film Pt heaters for a polymeric PCR chip.

    Science.gov (United States)

    Jeong, Sangdo; Lim, Juhun; Kim, Mi-Young; Yeom, JiHye; Cho, Hyunmin; Lee, Hyunjung; Shin, Yong-Beom; Lee, Jong-Hyun

    2018-01-29

    Polymerase chain reaction (PCR) has been widely used for major definite diagnostic tool, but very limited its place used only indoor such as hospital or diagnosis lab. For the rapid on-site detection of pathogen in an outdoor environment, a low-power cordless polymerase chain reaction (PCR) thermal cycler is crucial module. At this point of view, we proposed a low-power PCR thermal cycler that could be operated in an outdoor anywhere. The disposable PCR chip was made of a polymeric (PI/PET) film to reduce the thermal mass. A dual arrangement of the Pt heaters, which were positioned on the top and bottom of the PCR chip, improved the temperature uniformity. The temperature sensor, which was made of the same material as the heater, utilized the temperature dependence of the Pt resistor to ensure simple fabrication of the temperature sensor. Cooling the PCR chip using dual blower fans enabled thermal cycling to operate with a lower power than that of a Peltier element with a high power consumption. The PCR components were electrically connected to a control module that could be operated with a Li-ion battery (12 V), and the PCR conditions (temperature, time, cycle, etc.) were inputted on a touch screen. For 30 PCR cycles, the accumulated power consumption of heating and cooling was 7.3 Wh, which is easily available from a compact battery. Escherichia coli genomic DNA (510 bp) was amplified using the proposed PCR thermal cycler and the disposable PCR chip. A similar DNA amplification capability was confirmed using the proposed portable and low-power thermal cycler compared with a conventional thermal cycler.

  10. Thin Film Evaporation of Receding Meniscus within Micro Pillar Arrays

    Science.gov (United States)

    Alhosani, Mohamed H.; Alsheghri, Ammar A.; Alghaferi, Amal; Zhang, Tiejun

    2015-03-01

    Evaporation is a key process in power generation, water desalination, and thermal management applications. It has been proved that hydrophilic micro structured surfaces can enhance the convection heat transfer by promoting high-performance thin film evaporation and enlarging the total heat transfer surface area. When depositing a water droplet on hydrophilic structured surfaces, two distinct regions can be observed, a) central region with water level higher than the micro pillar height (droplet region), b) thin film region as a result of liquid meniscus receding among micro structures. In this study, we are able to probe the physics of thin film evaporation of receding liquid meniscus among micro pillar arrays with different pillar heights, spacings and diameters. Heat transfer is systematically studied in the droplet and thin film region for each sample. Also, Young-Laplace equation and kinetic theory of mass transport are used to model the thin film evaporation around micro pillars. With the proposed model, the shape of meniscus around micro pillars and the diameter of droplet/extended thin film region can be predicted and compared with the experimental measurement. The model can also be extended to model thin film evaporation of meniscus within nano structured surfaces. Supported by cooperative agreement between Masdar Inst and MIT.

  11. A simple model for the prediction of thermal conductivity of Ge2Sb2Te5 thin film

    International Nuclear Information System (INIS)

    Jin, Jae Sik

    2013-01-01

    A modified version of the Mayadas-Shatzkes (MS) model is proposed for the prediction of the thermal conductivity of both amorphous and crystalline of Ge 2 Sb 2 Te 5 (GST) phase-change materials at room temperature. The structural parameters of the original MS model are extended to describe the additional disorder scattering effects caused by the ternary components of the GST. The effect of disorder due to the alloy composition on the grain boundary scattering can be interpreted with the aid of thermal models. It is also found that for all phases of GST, the contribution of disorder scattering to the thermal resistance is nearly uniform. This is consistent with the fact that the GST phase changes without any destruction of the structural basis such as the building blocks.

  12. Study of structural and morphological properties of thermally evaporated Sn{sub 2}Sb{sub 6}S{sub 11} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ben Mehrez, N., E-mail: najia.benmehrez@gmail.com [Université Tunis El Manar, Laboratoire de Photovoltaïque et Matériaux Semi-conducteurs, ENIT, BP 37, Le belvédère, 1002 Tunis (Tunisia); Khemiri, N. [Université Tunis El Manar, Laboratoire de Photovoltaïque et Matériaux Semi-conducteurs, ENIT, BP 37, Le belvédère, 1002 Tunis (Tunisia); Kanzari, M. [Université Tunis El Manar, Laboratoire de Photovoltaïque et Matériaux Semi-conducteurs, ENIT, BP 37, Le belvédère, 1002 Tunis (Tunisia); Institut Préparatoire aux Etudes d’Ingénieurs de Tunis Montfleury, Université de Tunis (Tunisia)

    2016-10-01

    In this study, we report the structural and morphological properties of the new material Sn{sub 2}Sb{sub 6}S{sub 11} thin films prepared on glass substrates by vacuum thermal evaporation at various substrate temperatures (30, 60, 100, 140, 180 and 200 °C). Sn{sub 2}Sb{sub 6}S{sub 11} ingot was synthesized by the horizontal Bridgman technique. The structural properties of Sn{sub 2}Sb{sub 6}S{sub 11} powder were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy. The films were characterized for their structural properties by using XRD. All films were polycrystalline in nature. The variations of the structural parameters of the films with the substrate temperature were investigated. The results show that the crystallite sizes increase as the substrate temperature increases. The morphological properties of the films were analyzed by atomic force microscopy (AFM). The roughness and the topography of the surface of the films strongly depend on the substrate temperature. - Highlights: • Sn{sub 2}Sb{sub 6}S{sub 11} powder was successfully synthesized by the horizontal Bridgman technique. • Sn{sub 2}Sb{sub 6}S{sub 11} films were grown by thermal evaporation at different substrate temperatures. • Structural properties of Sn{sub 2}Sb{sub 6}S{sub 11} powder were investigated. • The effect of the substrate temperature on structural and morphological of Sn{sub 2}Sb{sub 6}S{sub 11} films properties was studied.

  13. Luminescence from thulium and samarium doped amorphous AlN thin films deposited by RF magnetron sputtering and the effect of thermal activation on luminescence

    Science.gov (United States)

    Maqbool, M.

    2006-04-01

    Thin films of thulium and samarium doped AlN are deposited on silicon (111) substrates at 77 K by rf magnetron sputtering method. 200 400 nm thick films are grown at 100 200 watts RF power and 5 8 mtorr nitrogen, using a metal target of Al with Tm and Sm separately. X-rays diffraction results show that films are amorphous. Cathodoluminescence studies are performed at room temperature and two dominant peaks are observed in Tm at 467 nm from 1D2 to 3F4 transition and 480 nm from 1G{4} to the ground state 3H{6} transition. Other peaks in the visible region are obtained at 650 nm and 685 nm due to 1G4 to 3F4 and 1D2 to 3H4 transitions. Peaks in the ultraviolet and infrared region are also obtained at 371 nm, and 802 nm as a result from 1D2 to 3H6 and 3H4 to 3H6 transition respectively. Sm gives four peaks at 564 nm, 600 nm, 648 nm and 707 nm as a result of 4G5/2 to 6H5/2 , 4G5/2 to 6H7/2, 4G5/2 to 6H9/2 and 4G5/2 to 6H11/2 transitions. Films are thermally activated at 1200 K for half an hour in a nitrogen atmosphere. Thermal activation enhances the intensity of luminescence.

  14. Influence of Annealing on the Optical Parameters of In2S3 Thin Films Produced by Thermal Evaporation

    Science.gov (United States)

    Izadneshan, H.; Gremenok, V. F.

    2014-05-01

    In2S3 thin fi lms are grown on glass substrates by vacuum thermal evaporation followed by annealing in vacuum between 330 and 400 °C for different time durations. We have investigated the infl uence of the annealing parameters on the characteristics of thin fi lms. It is shown that thermal treatment changed the crystal structure and optical energy band gap of In2S3 thin fi lms. Two energy band gaps were determined for all the fi lms, one indirect and the other direct.

  15. Large Energy Storage Density and High Thermal Stability in a Highly Textured (111)-Oriented Pb0.8Ba0.2ZrO3 Relaxor Thin Film with the Coexistence of Antiferroelectric and Ferroelectric Phases.

    Science.gov (United States)

    Peng, Biaolin; Zhang, Qi; Li, Xing; Sun, Tieyu; Fan, Huiqing; Ke, Shanming; Ye, Mao; Wang, Yu; Lu, Wei; Niu, Hanben; Zeng, Xierong; Huang, Haitao

    2015-06-24

    A highly textured (111)-oriented Pb0.8Ba0.2ZrO3 (PBZ) relaxor thin film with the coexistence of antiferroelectric (AFE) and ferroelectric (FE) phases was prepared on a Pt/TiOx/SiO2/Si(100) substrate by using a sol-gel method. A large recoverable energy storage density of 40.18 J/cm(3) along with an efficiency of 64.1% was achieved at room temperature. Over a wide temperature range of 250 K (from room temperature to 523 K), the variation of the energy density is within 5%, indicating a high thermal stability. The high energy storage performance was endowed by a large dielectric breakdown strength, great relaxor dispersion, highly textured orientation, and the coexistence of FE and AFE phases. The PBZ thin film is believed to be an attractive material for applications in energy storage systems over a wide temperature range.

  16. Dielectric Properties of Thermal and Plasma-Assisted Atomic Layer Deposited Al2O3 Thin Films

    NARCIS (Netherlands)

    Jinesh, K. B.; van Hemmen, J. L.; M. C. M. van de Sanden,; Roozeboom, F.; Klootwijk, J. H.; Besling, W. F. A.; Kessels, W. M. M.

    2011-01-01

    A comparative electrical characterization study of aluminum oxide (Al2O3) deposited by thermal and plasma-assisted atomic layer depositions (ALDs) in a single reactor is presented. Capacitance and leakage current measurements show that the Al2O3 deposited by the plasma-assisted ALD shows excellent

  17. Spin mediated magneto-electro-thermal transport behavior in Ni80Fe20/MgO/p-Si thin films

    Science.gov (United States)

    Lou, P. C.; Beyermann, W. P.; Kumar, S.

    2017-09-01

    In Si, the spin-phonon interaction is the primary spin relaxation mechanism. At low temperatures, the absence of spin-phonon relaxation will lead to enhanced spin accumulation. Spin accumulation may change the electro-thermal transport within the material, and thus may serve as an investigative tool for characterizing spin-mediated behavior. Here, we present the first experimental proof of spin accumulation induced electro-thermal transport behavior in a Pd (1 nm)/Ni80Fe20 (25 nm)/MgO (1 nm)/p-Si (2 μm) specimen. The spin accumulation originates from the spin-Hall effect. The spin accumulation changes the phononic thermal transport in p-Si causing the observed magneto-electro-thermal transport behavior. We also observe the inverted switching behavior in magnetoresistance measurement at low temperatures in contrast to magnetic characterization, which is attributed to the canted spin states in p-Si due to spin accumulation. The spin accumulation is elucidated by current dependent anomalous Hall resistance measurement, which shows a decrease as the electric current is increased. This result may open a new paradigm in the field of spin-mediated transport behavior in semiconductor and semiconductor spintronics.

  18. Diphenyl derivatives of dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene: organic semiconductors for thermally stable thin-film transistors.

    Science.gov (United States)

    Kang, Myeong Jin; Miyazaki, Eigo; Osaka, Itaru; Takimiya, Kazuo; Nakao, Akiko

    2013-04-10

    Two isomeric diphenyl-dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DPh-DNTTs), 2,9- and 3,10-DPh-DNTT, were characterized by means of single-crystal X-ray analysis, thin film XRDs, and evaluation of organic field-effect transistors (OFETs) using their evaporated thin films. The packing structures both in the single crystal and thin film state were classified into a typical herringbone packing regardless of the substitution positions, similar to the parent DNTT. The OFETs showed typical p-channel transistor characteristics with mobilities of as high as 3.5 cm2 V(-1) s(-1) for both isomers, which is slightly higher than that of the parent DNTT. Compared to related DNTT-based organic semiconductors, a unique point of DPh-DNTTs was found to be superior thermal stability in OFET devices. In particular, the 2,9-DPh-DNTT-based OFETs preserved its superior FET characteristics up to 250 °C. For its excellent thermal stability with good FET characteristics, 2,9-DPh-DNTT can be a useful organic semiconductor in various applications that require processes at high temperatures.

  19. New spreading law of thin film liquids controlled by gravity and vdW forces under thermal fluctuations

    Science.gov (United States)

    Nesic, Svetozar; Cuerno Rejado, Rodolfo; Moro Egido, Esteban

    2013-11-01

    It has been shown that, in the regime controlled by surface tension, the spreading dynamics of a thin viscous fluid droplet changes significantly when it is subjected to thermal fluctuations. Technically, this has been accomplished through the incorporation of appropriate stochastic terms into the standard lubrication equation. In practice, it leads to a modification of the classic Tanner's law for spreading, with implications for Micro and Nanofluidic systems. We have recently found a new law of spreading for the same kind of systems, but in the gravity-dominated regime. Moreover, in the deteministic case a finite contact angle is formed when a van der Waals attractive force is introduced to the system and we show that there is a slight change in contact angle when thermal fluctuations are taken into account. Ph.D student and a member of GISC (http://matematicas.uc3m.es/index.php/gisc).

  20. Experimental determination of thermal conductivities of dielectric thin films; Determination experimentale des conductivites thermiques de couches minces dielectriques

    Energy Technology Data Exchange (ETDEWEB)

    Scudeller, Y.; Hmina, N.; Lahmar, J.; Bardon, J.P. [Nantes Univ., 44 (France)

    1996-12-31

    This paper presents a method of measurement of thermal conductivity of sub-micron dielectric films in a direction perpendicular to the substrate. These films (oxides, nitrides, diamond..) are mainly used for the electrical insulation of semiconductor circuits and in optical treatments of high energy lasers. The principle of the method used and the experimental device are described. The results obtained with silicon oxides are discussed. (J.S.) 13 refs.

  1. Peel resistance characterization of localized polymer film bonding via thin film adhesive thermally activated by scanned CO2 laser

    Science.gov (United States)

    Dowding, Colin; Dowding, Robert; Griffiths, Jonathan; Lawrence, Jonathan

    2013-06-01

    Thermal laser polymer bonding is a non-contact process for the joining of polymer laminates using thermally activated adhesives. Conventional, contact based bonding techniques suffer from mechanical wear, geometric inflexibility and poor energy efficiency. The application of lasers offers the potential for highly localized delivery of energy and increased process flexibility whilst achieving controlled and repeatable bonding of polymer laminates in a contact free process. Unlike previously reported techniques, here it is reported that laser based non-contact bonding is both viable and highly desirable due to the increased levels of control it affords the user. In this work, laser polymer bonding of 75 μm thick linear low density polyethylene (LLDPE) film backed with a thermally activated adhesive to a 640 μm thick polypropylene (PP) substrate was conducted using continuous wave 10.6 μm laser radiation and scanning galvanometric optics. The effect of laser power and scanning traverse speed on the peel resistance properties of the bonded polymer laminates is presented, with a threshold specific energy density for successful adhesive activation determined.

  2. Detection of impact damage on thermal protection systems using thin-film piezoelectric sensors for integrated structural health monitoring

    Science.gov (United States)

    Na, Jeong K.; Kuhr, Samuel J.; Jata, Kumar V.

    2008-03-01

    Thermal Protection Systems (TPS) can be subjected to impact damage during flight and/or during ground maintenance and/or repair. AFRL/RXLP is developing a reliable and robust on-board sensing/monitoring capability for next generation thermal protection systems to detect and assess impact damage. This study was focused on two classes of metallic thermal protection tiles to determine threshold for impact damage and develop sensing capability of the impacts. Sensors made of PVDF piezoelectric film were employed and tested to evaluate the detectability of impact signals and assess the onset or threshold of impact damage. Testing was performed over a range of impact energy levels, where the sensors were adhered to the back of the specimens. The PVDF signal levels were analyzed and compared to assess damage, where digital microscopy, visual inspection, and white light interferometry were used for damage verification. Based on the impact test results, an assessment of the impact damage thresholds for each type of metallic TPS system was made.

  3. Interfaces and thin films physics

    International Nuclear Information System (INIS)

    Equer, B.

    1988-01-01

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

  4. Handbook of thin film technology

    CERN Document Server

    Frey, Hartmut

    2015-01-01

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

  5. Rapid thermal annealed Molybdenum back contact for Cu2ZnSnS4 thin film solar cells

    Science.gov (United States)

    Liu, Xiaolei; Cui, Hongtao; Kong, Charlie; Hao, Xiaojing; Huang, Yidan; Liu, Fangyang; Song, Ning; Conibeer, Gavin; Green, Martin

    2015-03-01

    In this work, an industrially viable manufacturing process—rapid thermal annealing (RTA) of Molybdenum back contact is proposed and investigated to improve the performance of sputtered Cu2ZnSnS4 (CZTS) solar cells. The RTA process was found to facilitate Na diffusion from soda lime glass to Mo as well as CZTS and improve the crystallinity of the Mo film. Consequently, the surface morphology of the subsequently deposited CZTS absorbers is improved, which results in significant enhancement of open circuit voltage, short-circuit current density, fill factor, and conversion efficiency.

  6. Rapid thermal annealed Molybdenum back contact for Cu2ZnSnS4 thin film solar cells

    International Nuclear Information System (INIS)

    Liu, Xiaolei; Cui, Hongtao; Kong, Charlie; Hao, Xiaojing; Huang, Yidan; Liu, Fangyang; Song, Ning; Conibeer, Gavin; Green, Martin

    2015-01-01

    In this work, an industrially viable manufacturing process—rapid thermal annealing (RTA) of Molybdenum back contact is proposed and investigated to improve the performance of sputtered Cu 2 ZnSnS 4 (CZTS) solar cells. The RTA process was found to facilitate Na diffusion from soda lime glass to Mo as well as CZTS and improve the crystallinity of the Mo film. Consequently, the surface morphology of the subsequently deposited CZTS absorbers is improved, which results in significant enhancement of open circuit voltage, short-circuit current density, fill factor, and conversion efficiency

  7. Silver nanoparticles with an armor layer embedded in the alumina matrix to form nanocermet thin films with sound thermal stability.

    Science.gov (United States)

    Gao, Junhua; Tu, Chengjun; Liang, Lingyan; Zhang, Hongliang; Zhuge, Fei; Wu, Liang; Cao, Hongtao; Yu, Ke

    2014-07-23

    In this article, we demonstrate that the Al-alloyed Ag nanoparticle-embedded alumina nanocermet films lead to excellent thermal stability, even at 500 °C for 130 h under an ambient nitrogen atmosphere. The outward diffusion of Al atoms from the AgAl bimetallic alloy nanoparticles and their easy oxidation create an armor layer to suppress the mobility of Ag atoms. Then, the AlAg particles or/and agglomerates with a uniform spherical shape favor higher dispersion concentration within the host matrix, which is beneficial both for high absorptance in the visible range and for the solid localized surface plasmon absorption features in the AgAl-Al2O3 nanocermet films. Based on the AgAl-Al2O3 absorbing layer with sound optical and microstructural stability, we successfully constructed a high-temperature-endurable solar selective absorber. The multilayer stacked absorber demonstrates a high solar absorptance of ∼94.2% and a low thermal emittance of ∼15% (@ 673 K) after annealing at 450 °C for 70 h in an ambient nitrogen atmosphere.

  8. 3{omega} measurements of half-Heusler thin films using a passive circuit

    Energy Technology Data Exchange (ETDEWEB)

    Mix, Christian; Jaeger, Tino; Jakob, Gerhard [Institut fuer Physik, Universitaet Mainz, Staudinger Weg 7, 55128 Mainz (Germany)

    2011-07-01

    One possibility to increase the thermoelectric Figure-of-Merit of thin films is to decrease the thermal conductivity, by replacing the thin film with a superlattice of the same thickness. This is one of the major challenges in ongoing research. For this purpose a 3{omega}-measurement system is built up to obtain the thermal conductivity of thin films. To nullify influences of active elements, a setup including a wheatstone bridge is used. Different aspects of the measurement system like the influence of thermal penetration depth and the energy losses by atmosphere are discussed. Additionally, first results on Half-Heusler thin films and superlattices are presented.

  9. Substrate heater for thin film deposition

    Science.gov (United States)

    Foltyn, Steve R.

    1996-01-01

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

  10. Characterization of organic thin films

    CERN Document Server

    Ulman, Abraham; Evans, Charles A

    2009-01-01

    Thin films based upon organic materials are at the heart of much of the revolution in modern technology, from advanced electronics, to optics to sensors to biomedical engineering. This volume in the Materials Characterization series introduces the major common types of analysis used in characterizing of thin films and the various appropriate characterization technologies for each. Materials such as Langmuir-Blodgett films and self-assembled monolayers are first introduced, followed by analysis of surface properties and the various characterization technologies used for such. Readers will find detailed information on: -Various spectroscopic approaches to characterization of organic thin films, including infrared spectroscopy and Raman spectroscopy -X-Ray diffraction techniques, High Resolution EELS studies, and X-Ray Photoelectron Spectroscopy -Concise Summaries of major characterization technologies for organic thin films, including Auger Electron Spectroscopy, Dynamic Secondary Ion Mass Spectrometry, and Tra...

  11. Rare Earth Oxide Thin Films

    CERN Document Server

    Fanciulli, Marco

    2007-01-01

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

  12. A p-silicon nanowire/n-ZnO thin film heterojunction diode prepared by thermal evaporation

    International Nuclear Information System (INIS)

    Hazra, Purnima; Jit, S.

    2014-01-01

    This paper represents the electrical and optical characteristics of a SiNW/ZnO heterojunction diode and subsequent studies on the photodetection properties of the diode in the ultraviolet (UV) wavelength region. In this work, silicon nanowire arrays were prepared on p-type (100)-oriented Si substrate by an electroless metal deposition and etching method with the help of ultrasonication. After that, catalyst-free deposition of zinc oxide (ZnO) nanowires on a silicon nanowire (SiNW) array substrate was done by utilizing a simple and cost-effective thermal evaporation technique without using a buffer layer. The SEM and XRD techniques are used to show the quality of the as-grown ZnO nanowire film. The junction properties of the diode are evaluated by measuring current—voltage and capacitance—voltage characteristics. The diode has a well-defined rectifying behavior with a rectification ratio of 190 at ±2 V, turn-on voltage of 0.5 V, and barrier height is 0.727 eV at room temperature under dark conditions. The photodetection parameters of the diode are investigated in the bias voltage range of ±2 V. The diode shows responsivity of 0.8 A/W at a bias voltage of 2 V under UV illumination (wavelength = 365 nm). The characteristics of the device indicate that it can be used for UV detection applications in nano-optoelectronic and photonic devices. (semiconductor devices)

  13. A thermalization energy analysis of the threshold voltage shift in amorphous indium gallium zinc oxide thin film transistors under positive gate bias stress

    NARCIS (Netherlands)

    Niang, K.M.; Barquinha, P.M.C.; Martins, R.F.P.; Cobb, B.; Powell, M.J.; Flewitt, A.J.

    2016-01-01

    Thin film transistors (TFTs) employing an amorphous indium gallium zinc oxide (a-IGZO) channel layer exhibit a positive shift in the threshold voltage under the application of positive gate bias stress (PBS). The time and temperature dependence of the threshold voltage shift was measured and

  14. Effect of thermal treatment on solid–solid interface of hematite thin film synthesized by spin-coating deposition solution

    International Nuclear Information System (INIS)

    Bellido-Aguilar, Daniel Angel; Tofanello, Aryane; Souza, Flavio L.; Furini, Leonardo Negri; Constantino, Carlos José Leopoldo

    2016-01-01

    This work describes hematite films prepared by a spin-coating deposition solution (SCDS) method that is a sol–gel method derived technique. Hematite films were prepared at two heat treatment temperatures (500 °C and 800 °C) and the influence of thermal treatment on the photoelectrochemical performance was studied. In addition, since the SCDS method allows an optimal control of stoichiometry and impurity incorporation, hematite films modified with Zn 2+ and Sn 4+ were also prepared. The 800 °C-treated hematite films had a higher wettability and roughness that enabled them to have a better photocatalytic response in comparison with that of 500 °C-treated hematite films. Moreover, modified hematite films demonstrated to have a performance slightly better than that of undoped hematite film as shown in linear sweep voltammetry and chronoamperometry results. Although an improvement in the performance of hematite films was achieved by annealing at higher temperatures and incorporating Zn 2+ or Sn 4+ , the general photocatalytic response of the films was poor. Two plausible hypotheses were discussed related to the (i) dopant segregation at grain boundary, and (ii) poor contact between the hematite and fluorine doped tin oxide layer (from the glass substrate), which was experimentally confirmed by a cross-sectional analysis conducted using scanning electron microscopy (SEM). In fact, additional experiments need to be done in order to improve the hematite deposition and make the SCDS a promise method for industrial application. - Highlights: • High temperature of annealing decreases the hematite adherence and performance. • Zn 2+ and Sn 4+ dopants affected differently the photocurrent onset potentials. • Dopants affected the grain size due to their segregation at grain boundaries.

  15. Buckling of Thin Films in Nano-Scale

    Directory of Open Access Journals (Sweden)

    Li L.A.

    2010-06-01

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

  16. Buckling of Thin Films in Nano-Scale

    Science.gov (United States)

    Wang, S.; Jia, H. K.; Sun, J.; Ren, X. N.; Li, L. A.

    2010-06-01

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

  17. Thermoelectric properties of TiNiSn and Zr0.5Hf0.5NiSn thin films and superlattices with reduced thermal conductivities

    International Nuclear Information System (INIS)

    Jaeger, Tino

    2013-01-01

    Rising energy costs and enhanced CO 2 emission have moved research about thermoelectric (TE) materials into focus. The suitability of a material for usage in TE devices depends on the figure of merit ZT and is equal to α 2 σTκ -1 including Seebeck coefficient α, conductivity σ, temperature T and thermal conductivity κ. Without affecting the power factor α 2 σ, using nanostructuring, ZT should here be increased by a depressed thermal conductivity. As half-Heusler (HH) bulk materials, the TE properties of TiNiSn and Zr 0.5 Hf 0.5 NiSn have been extensively studied. Here, semiconducting TiNiSn and Zr 0.5 Hf 0.5 NiSn thin films were fabricated for the first time by dc magnetron sputtering. On MgO (100) substrates, strongly textured polycrystalline films were obtained at substrate temperatures of about 450 C. The film consisted of grains with an elongation perpendicular to the surface of 55 nm. These generated rocking curves with FWHMs of less than 1 . Structural analyses were performed by X ray diffraction (XRD). Having deposition rates of about 1 nms -1 within shortest time also films in the order of microns were fabricated. For TiNiSn the highest in-plane power factor of about 0.4 mWK -2 m -1 was measured at about 550 K. In addition, at room temperature a cross-plane thermal conductivity of 2.8 Wm -1 K -1 was observed by the differential 3ω method. Because the reduction of thermal conductivity by mass fluctuation is well-known and interface scattering of phonons is expected, superlattices (SL) were fabricated. Therefore, TiNiSn and Zr 0.5 Hf 0.5 NiSn were successively deposited. While the sputter cathodes were continuously running, for fabrication of SLs the substrates were moved from one to another. The high crystal quality of the SLs and the sharp interfaces were proven by satellite peaks (XRD) and Scanning Transmission Electron Microscopy (STEM). For a SL with a periodicity of 21 nm (TiNiSn and Zr 0.5 Hf 0.5 NiSn each 15 nm) at a temperature of 550 K an

  18. Adhesion of Antireflective Coatings in Multijunction Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-21

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

  19. Analysis of non-contact and contact probe-to-sample thermal exchange for quantitative measurements of thin film and nanostructure thermal conductivity by the scanning hot probe method

    Science.gov (United States)

    Wilson, Adam A.

    The ability to measure thermal properties of thin films and nanostructured materials is an important aspect of many fields of academic study. A strategy especially well-suited for nanoscale investigations of these properties is the scanning hot probe technique, which is unique in its ability to non-destructively interrogate the thermal properties with high resolution, both laterally as well as through the thickness of the material. Strategies to quantitatively determine sample thermal conductivity depend on probe calibration. State of the art calibration strategies assume that the area of thermal exchange between probe and sample does not vary with sample thermal conductivity. However, little investigation has gone into determining whether or not that assumption is valid. This dissertation provides a rigorous study into the probe-to-sample heat transfer through the air gap at diffusive distances for a variety of values of sample thermal conductivity. It is demonstrated that the thermal exchange radius and gap/contact thermal resistance varies with sample thermal conductivity as well as tip-to-sample clearance in non-contact mode. In contact mode, it is demonstrated that higher thermal conductivity samples lead to a reduction in thermal exchange radius for Wollaston probe tips. Conversely, in non-contact mode and in contact mode for sharper probe tips where air contributes the most to probe-to-sample heat transfer, the opposite trend occurs. This may be attributed to the relatively strong solid-to-solid conduction occurring between probe and sample for the Wollaston probes. A three-dimensional finite element (3DFE) model was developed to investigate how the calibrated thermal exchange parameters vary with sample thermal conductivity when calibrating the probe via the intersection method in non-contact mode at diffusive distances. The 3DFE model was then used to explore the limits of sensitivity of the experiment for a range of simulated experimental conditions. It

  20. Investigation of thin film energy-saving coatings

    Directory of Open Access Journals (Sweden)

    Bukhmirov Vyacheslav

    2017-01-01

    Full Text Available The report presents the results of an experimental study of the thermophysical properties and energy efficiency of thin-film energy-saving coatings consisting of hollow microspheres and a binder material from styrene-acrylic dispersion. The value of the thermal conductivity coefficient of the energy-saving paint is estimated depending on its composition and temperature, and the thermal diffusivity coefficient is determined. Experimental results of energy efficiency of using thin-film coatings for insulation of facades of buildings and as thermal insulation for pipelines with a hot coolant are presented.

  1. Production and characterization of layer by layer sputtered single-phase AgInSe{sub 2} thin film by thermal selenization

    Energy Technology Data Exchange (ETDEWEB)

    Kaleli, M. [Department of Physics, Süleyman Demirel University, 32260 İsparta (Turkey); Çolakoğlu, T. [Department of Electrical Engineering, Middle East Technical University, 06800 Ankara (Turkey); Parlak, M., E-mail: parlak@metu.edu.tr [Department of Physics, Middle East Technical University, Inonu Bulv, 06800 Ankara (Turkey)

    2013-12-01

    In this study highly stoichiometric and monophase AgInSe{sub 2} thin films were prepared by selenization of Ag–InSe precursors and the effect of the annealing temperature on the structural, electrical and optical properties have been investigated. The Se incorporation during selenization process as a function of temperature and the compositions of the samples were determined by energy dispersive X-ray analysis (EDAX). As prepared and selenized films were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Hall effect and photoresponse measurements at room temperature. XRD analysis depicted that the crystal structure of AgInSe{sub 2} film was monophase with preferred orientation along the (1 1 2) direction and the lattice parameters a = 6.09, b = 6.09 and c = 11.67 Å. The structural evolution was clearly diagnosed by the increase of film thickness during selenization process. It was observed from SEM measurements that the average values of grain size ranging from 0.5 to 4 μm on the surface of AgInSe{sub 2} thin films by increasing selenization temperature from 300 to 450 °C. Room temperature conductivity and carrier concentrations of selenized samples determined by means of Hall measurements were found in the range of 0.03–0.88 (Ω-cm){sup −1} and 1.35 × 10{sup 15}–7.09 × 10{sup 18} (cm{sup −3}), respectively. The band gaps of these samples were investigated by spectral photoresponse measurement under light bias in the range of 1.05–2.10 eV. The two stage selenization process is introduced as an applicable approach to fabricate pure monophase AgInSe{sub 2} thin films for the usage in thin-film solar cell applications.

  2. In-situ X-Ray Analysis of Rapid Thermal Processing for Thin-Film Solar Cells: Closing the Gap between Production and Laboratory Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Toney, Michael F. [SLAC National Accelerator Lab., Menlo Park, CA (United States); van Hest, Maikel F. A. M. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-02-21

    For materials synthesis, it is well known that the material final state may not reach equilibrium and depends on the synthetic process. In particular, processes that quickly remove the available energy from the material may leave it in a metastable state and the metastability may actually impart desirable functional properties. By its very nature, Rapid thermal processing (RTP) is ideally suited to produce such metastable materials. However, metastability and the dynamics of reaching a metastable state are poorly understood, since this is best accomplished through in situ monitoring. In this regard, RTP is particularly challenging as the processing time are very short (seconds to minutes). As a result, there is only poor understanding, and hence use, of RTP in industry. This is potentially a cost-increasing limitation, because RTP can decrease cost by decreasing processing time, and as such, increase throughput and decrease the total thermal budget of processing - a significant cost. RTP is already being used for key processing steps in PV technologies. With silicon wafer PV, it is used for establishing electrical contact between the Ag metal grid and the silicon (known as firing). In this process, a silicon wafer with deposited metal/frit in a grid pattern is heated rapidly to temperatures between 750 and 800 ºC. The processing time when the temperature is held above 600ºC is short (<5 seconds). This process has historically been optimized empirically and it is unclear how the thermal processing affects formation of the final contact between the metal and the silicon. In the case of thin-film PV, RTP has been demonstrated in the process of making absorber layers, i.e. CIGS and CZTS. Use of RTP can reduce the processing time from 10s of minutes to seconds, reducing the thermal budget and increasing the throughput significantly. The conversion from precursor material to final PV material is not well understood, and most of the process optimization is done

  3. Superstrate sub-cell voltage-matched multijunction solar cells

    Science.gov (United States)

    Mascarenhas, Angelo; Alberi, Kirstin

    2016-03-15

    Voltage-matched thin film multijunction solar cell and methods of producing cells having upper CdTe pn junction layers formed on a transparent substrate which in the completed device is operatively positioned in a superstate configuration. The solar cell also includes a lower pn junction formed independently of the CdTe pn junction and an insulating layer between CdTe and lower pn junctions. The voltage-matched thin film multijunction solar cells further include a parallel connection between the CdTe pn junction and lower pn junctions to form a two-terminal photonic device. Methods of fabricating devices from independently produced upper CdTe junction layers and lower junction layers are also disclosed.

  4. Characterization of Sucrose Thin Films for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    S. L. Iconaru

    2011-01-01

    Full Text Available Sucrose is a natural osmolyte accumulated in the cells of organisms as they adapt to environmental stress. In vitro sucrose increases protein stability and forces partially unfolded structures to refold. Thin films of sucrose (C12H22O11 were deposited on thin cut glass substrates by the thermal evaporation technique (P∼10−5 torr. Characteristics of thin films were put into evidence by Fourier Transform Infrared Spectroscopy (FTIR, X-ray Photoelectron Spectroscopy (XPS, scanning electron microscopy (SEM, and differential thermal analysis and thermal gravimetric analysis (TG/DTA. The experimental results confirm a uniform deposition of an adherent layer. In this paper we present a part of the characteristics of sucrose thin films deposited on glass in medium vacuum conditions, as a part of a culture medium for osteoblast cells. Osteoblast cells were used to determine proliferation, viability, and cytotoxicity interactions with sucrose powder and sucrose thin films. The osteoblast cells have been provided from the American Type Culture Collection (ATCC Centre. The outcome of this study demonstrated the effectiveness of sucrose thin films as a possible nontoxic agent for biomedical applications.

  5. Preparation and optical and electrical evaluation of bulk SiO{sub 2} sonogel hybrid composites and vacuum thermal evaporated thin films prepared from molecular materials derived from (Fe, Co) metallic phthalocyanines and 1,8 dihydroxiantraquinone compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Vergara, Maria Elena [Coordinacion de Ingenieria Mecatronica, Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786 Huixquilucan, Estado de Mexico (Mexico); Morales-Saavedra, Omar G. [Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, CCADET-UNAM, A.P. 70-186, Coyoacan, 04510 Mexico, D.F. (Mexico)], E-mail: omar.morales@ccadet.unam.mx; Ontiveros-Barrera, Fernando G.; Torres-Zuniga, Vicente; Ortega-Martinez, Roberto [Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, CCADET-UNAM, A.P. 70-186, Coyoacan, 04510 Mexico, D.F. (Mexico); Ortiz Rebollo, Armando [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, IIM-UNAM, A.P. 70-360, Coyoacan, 04510 Mexico, D.F. (Mexico)

    2009-02-25

    Semiconducting molecular material of PcFe(CN)L1 and PcCo(CN)L1 (L1 = 1,8 dihydroxianthraquinone), PcFe(CN)L2 and PcCo(CN)L2 (L2 = double potassium salt of 1,8 dihydroxianthraquinone) have been successfully used to prepare thin film and bulk sol-gel hybrid optical materials. These samples were developed according to the vacuum thermal evaporation technique and the catalyst-free sonogel route, respectively. Thin films samples were deposited on Corning glass substrates and crystalline silicon wafers and were characterized by infrared (FTIR), Raman and ultraviolet-visible (UV-vis) spectroscopies. IR-spectroscopy and Raman studies unambiguously confirmed that the molecular material thin films exhibit the same intra-molecular bonds, which suggests that the thermal evaporation process does not alter these bonds significantly. These results show that it is possible to deposit molecular materials of PcFe(CN)L2 and PcCo(CN)L2 on Corning glass substrates and silicon wafers. From the UV-vis studies the optical band gap (E{sub g}) was evaluated. The effect of temperature on conductivity was also evaluated in these samples. Finally, the studied molecular systems dissolved at different concentrations in tetrahydrofuran (THF) were successfully embedded into a highly pure SiO{sub 2} sonogel network generated via sonochemical reactions to form several solid state, optically active sol-gel hybrid glasses. By this method, homogeneous and stable hybrid monoliths suitable for optical characterization can be produced. The linear optical properties of these amorphous bulk structures were determined by the Brewster angle method and by absorption-, Raman- and photoluminescent (PL)-spectroscopies, respectively.

  6. Preparation and optical and electrical evaluation of bulk SiO2 sonogel hybrid composites and vacuum thermal evaporated thin films prepared from molecular materials derived from (Fe, Co) metallic phthalocyanines and 1,8 dihydroxiantraquinone compounds

    International Nuclear Information System (INIS)

    Sanchez Vergara, Maria Elena; Morales-Saavedra, Omar G.; Ontiveros-Barrera, Fernando G.; Torres-Zuniga, Vicente; Ortega-Martinez, Roberto; Ortiz Rebollo, Armando

    2009-01-01

    Semiconducting molecular material of PcFe(CN)L1 and PcCo(CN)L1 (L1 = 1,8 dihydroxianthraquinone), PcFe(CN)L2 and PcCo(CN)L2 (L2 = double potassium salt of 1,8 dihydroxianthraquinone) have been successfully used to prepare thin film and bulk sol-gel hybrid optical materials. These samples were developed according to the vacuum thermal evaporation technique and the catalyst-free sonogel route, respectively. Thin films samples were deposited on Corning glass substrates and crystalline silicon wafers and were characterized by infrared (FTIR), Raman and ultraviolet-visible (UV-vis) spectroscopies. IR-spectroscopy and Raman studies unambiguously confirmed that the molecular material thin films exhibit the same intra-molecular bonds, which suggests that the thermal evaporation process does not alter these bonds significantly. These results show that it is possible to deposit molecular materials of PcFe(CN)L2 and PcCo(CN)L2 on Corning glass substrates and silicon wafers. From the UV-vis studies the optical band gap (E g ) was evaluated. The effect of temperature on conductivity was also evaluated in these samples. Finally, the studied molecular systems dissolved at different concentrations in tetrahydrofuran (THF) were successfully embedded into a highly pure SiO 2 sonogel network generated via sonochemical reactions to form several solid state, optically active sol-gel hybrid glasses. By this method, homogeneous and stable hybrid monoliths suitable for optical characterization can be produced. The linear optical properties of these amorphous bulk structures were determined by the Brewster angle method and by absorption-, Raman- and photoluminescent (PL)-spectroscopies, respectively

  7. Infrared control coating of thin film devices

    Energy Technology Data Exchange (ETDEWEB)

    Berland, Brian Spencer; Stowell, Jr., Michael Wayne; Hollingsworth, Russell

    2017-02-28

    Systems and methods for creating an infrared-control coated thin film device with certain visible light transmittance and infrared reflectance properties are disclosed. The device may be made using various techniques including physical vapor deposition, chemical vapor deposition, thermal evaporation, pulsed laser deposition, sputter deposition, and sol-gel processes. In particular, a pulsed energy microwave plasma enhanced chemical vapor deposition process may be used. Production of the device may occur at speeds greater than 50 Angstroms/second and temperatures lower than 200.degree. C.

  8. Stability of tetraphenyl butadiene thin films in liquid xenon

    International Nuclear Information System (INIS)

    Sanguino, P.; Balau, F.; Botelho do Rego, A.M.; Pereira, A.; Chepel, V.

    2016-01-01

    Tetraphenyl butadiene (TPB) is widely used in particle detectors as a wavelength shifter. In this work we studied the stability of TPB thin films when immersed in liquid xenon (LXe). The thin films were deposited on glass and quartz substrates by thermal evaporation. Morphological and chemical surface properties were monitored before and after immersion into LXe by scanning electron microscopy and X-ray photoelectron spectroscopy. No appreciable changes have been detected with these two methods. Grain size and surface chemical composition were found to be identical before and after submersion into LXe. However, the film thickness, measured via optical transmission in the ultraviolet–visible wavelength regions, decreased by 1.6 μg/cm 2 (24%) after immersion in LXe during 20 h. These results suggest the necessity of using a protective thin film over the Tetraphenyl butadiene when used as a wavelength shifter in LXe particle detectors. - Highlights: • Stability of tetraphenyl butadiene (TPB) thin films immersed in liquid xenon (LXe). • Thermally evaporated TPB thin films were immersed in LXe for 20 h. • Film morphology and chemical surface properties remained unchanged. • Surface density of the films decreased by 1.6 μg/cm 2 (24%) after immersion in LXe. • For using in LXe particle detectors, TPB films should be protected with a coating.

  9. Self-assembly of dodecaphenyl POSS thin films

    Science.gov (United States)

    Handke, Bartosz; Klita, Łukasz; Niemiec, Wiktor

    2017-12-01

    The self-assembly abilities of Dodecaphenyl Polyhedral Oligomeric Silsesquioxane thin films on Si(1 0 0) surfaces were studied. Due to their thermal properties - relatively low sublimation temperature and preservation of molecular structure - cage type silsesquioxanes are ideal material for the preparation of a thin films by Physical Vapor Deposition. The Ultra-High Vacuum environment and the deposition precision of the PVD method enable the study of early stages of thin film growth and its molecular organization. X-ray Reflectivity and Atomic Force Microscopy measurements allow to pursuit size-effects in the structure of thin films with thickness ranges from less than a single molecular layer up to several tens of layers. Thermal treatment of the thin films triggered phase change: from a poorly ordered polycrystalline film into a well-ordered multilayer structure. Self-assembly of the layers is the effect of the π-stacking of phenyl rings, which force molecules to arrange in a superlattice, forming stacks of alternating organic-inorganic layers.

  10. Electrical and optical properties of thermally-evaporated thin films from A{sub 2}[TiO(C{sub 2}O{sub 4}){sub 2}] (A = K, PPh{sub 4}) and 1,8-dihydroxyanthraquinone

    Energy Technology Data Exchange (ETDEWEB)

    Carbia-Ruelas, E. [Coordinacion de Ingenieria Mecatronica. Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico); Sanchez-Vergara, M.E., E-mail: elena.sanchez@anahuac.mx [Coordinacion de Ingenieria Mecatronica. Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico); Garcia-Montalvo, V. [Instituto de Quimica, Universidad Nacional Autonoma de Mexico. Circuito Exterior, Ciudad Universitaria, 04510, Mexico, D. F (Mexico); Morales-Saavedra, O.G. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, CCADET-UNAM. A. P. 70-186, Coyoacan, 04510, Mexico, D. F (Mexico); Alvarez-Bada, J.R. [Coordinacion de Ingenieria Mecatronica. Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786, Huixquilucan (Mexico)

    2011-02-01

    In this work, the synthesis of molecular materials formed from A{sub 2}[TiO(C{sub 2}O{sub 4}){sub 2}] (A = K, PPh4) and 1,8 dihydroxyanthraquinone is reported. The synthesized materials were characterized by atomic force microscopy (AFM), infrared (IR) and ultraviolet-visible (UV-vis) spectroscopy. IR spectroscopy showed that the molecular-material thin-films, deposited by vacuum thermal evaporation, exhibit the same intra-molecular vibration modes as the starting powders, which suggests that the thermal evaporation process does not alter the initial chemical structures. Electrical transport properties were studied by dc conductivity measurements. The electrical activation energies of the complexes, which were in the range of 0.003-1.16 eV, were calculated from Arrhenius plots. Optical absorption studies in the wavelength range of 190-1090 nm at room temperature showed that the optical band gaps of the thin films were around 1.9-2.3 eV for direct transitions Eg{sub d}. The cubic NLO effects were substantially enhanced for materials synthesized from K{sub 2}[TiO(C{sub 2}O{sub 4}){sub 2}], where {chi}{sup (3)} (-3{omega}; {omega}, {omega}, {omega}) values in the promising range of 10{sup -12} esu have been evaluated.

  11. Electrical and optical properties of thermally-evaporated thin films from A2[TiO(C2O4)2] (A = K, PPh4) and 1,8-dihydroxyanthraquinone

    International Nuclear Information System (INIS)

    Carbia-Ruelas, E.; Sanchez-Vergara, M.E.; Garcia-Montalvo, V.; Morales-Saavedra, O.G.; Alvarez-Bada, J.R.

    2011-01-01

    In this work, the synthesis of molecular materials formed from A 2 [TiO(C 2 O 4 ) 2 ] (A = K, PPh4) and 1,8 dihydroxyanthraquinone is reported. The synthesized materials were characterized by atomic force microscopy (AFM), infrared (IR) and ultraviolet-visible (UV-vis) spectroscopy. IR spectroscopy showed that the molecular-material thin-films, deposited by vacuum thermal evaporation, exhibit the same intra-molecular vibration modes as the starting powders, which suggests that the thermal evaporation process does not alter the initial chemical structures. Electrical transport properties were studied by dc conductivity measurements. The electrical activation energies of the complexes, which were in the range of 0.003-1.16 eV, were calculated from Arrhenius plots. Optical absorption studies in the wavelength range of 190-1090 nm at room temperature showed that the optical band gaps of the thin films were around 1.9-2.3 eV for direct transitions Eg d . The cubic NLO effects were substantially enhanced for materials synthesized from K 2 [TiO(C 2 O 4 ) 2 ], where χ (3) (-3ω; ω, ω, ω) values in the promising range of 10 -12 esu have been evaluated.

  12. Laser applications in thin-film photovoltaics

    OpenAIRE

    Bartlome, R.; Strahm, B.; Sinquin, Y.; Feltrin, A.; Ballif, C.

    2009-01-01

    We review laser applications in thin-film photovoltaics (thin-film Si, CdTe, and Cu(In,Ga)Se2 solar cells). Lasers are applied in this growing field to manufacture modules, to monitor Si deposition processes, and to characterize opto-electrical properties of thin films. Unlike traditional panels based on crystalline silicon wafers, the individual cells of a thin-film photovoltaic module can be serially interconnected by laser scribing during fabrication. Laser scribing applications are descri...

  13. Nanocrystal thin film fabrication methods and apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Kagan, Cherie R.; Kim, David K.; Choi, Ji-Hyuk; Lai, Yuming

    2018-01-09

    Nanocrystal thin film devices and methods for fabricating nanocrystal thin film devices are disclosed. The nanocrystal thin films are diffused with a dopant such as Indium, Potassium, Tin, etc. to reduce surface states. The thin film devices may be exposed to air during a portion of the fabrication. This enables fabrication of nanocrystal-based devices using a wider range of techniques such as photolithography and photolithographic patterning in an air environment.

  14. Structural, optical and electrical properties of N-doped ZnO thin films prepared by thermal oxidation of pulsed filtered cathodic vacuum arc deposited Zn{sub x}N{sub y} films

    Energy Technology Data Exchange (ETDEWEB)

    Erdogan, N.H.; Kara, K.; Ozdamar, H. [Physics Department, Cukurova University, 01330 Adana (Turkey); Kavak, H., E-mail: hkavak@cu.edu.tr [Physics Department, Cukurova University, 01330 Adana (Turkey); Esen, R. [Physics Department, Cukurova University, 01330 Adana (Turkey); Karaagac, H. [Physics Department, Middle East Technical University, 06531 Ankara (Turkey)

    2011-09-08

    Graphical abstract: Highlights: > Thermal oxidation of Zn{sub x}N{sub y} method is used to obtain N doped ZnO. > N acceptors in ZnO is not sufficiently activated at oxidation temperature below 350 deg. C. > Oxidation treatment at 450 deg. C activates more N acceptors in ZnO. > Oxidation treatment at high temperatures above 550 deg. C reduces the N concentration in the ZnO thin film. - Abstract: In this study, N-doped ZnO thin films were fabricated by oxidation of Zn{sub x}N{sub y} films. The Zn{sub x}N{sub y} thin films were deposited on glass substrates by pulsed filtered cathodic vacuum arc deposition (PFCVAD) using metallic zinc wire (99.999%) as a cathode target in pure nitrogen plasma. The influence of oxidation temperature, on the electrical, structural and optical properties of N-doped ZnO films was investigated. P-type conduction was achieved for the N-doped ZnO obtained at 450 deg. C by oxidation of Zn{sub x}N{sub y}, with a resistivity of 16.1 {Omega} cm, hole concentration of 2.03 x 10{sup 16} cm{sup -3} and Hall mobility of 19 cm{sup 2}/V s. X-ray photoelectron spectroscopy (XPS) analysis confirmed the incorporation of N into the ZnO films. X-ray diffraction (XRD) pattern showed that the films as-deposited and oxidized at 350 deg. C were amorphous. However, the oxidized films in air atmosphere at 450-550 deg. C were polycrystalline without preferential orientation. In room temperature photoluminescence (PL) spectra, an ultraviolet (UV) peak was seen for all the samples. In addition, a broad deep level emission was observed.

  15. Morphological, Structural, and Optical Properties of Single-Phase Cu(In,GaSe2 Thin Films from the Selenization of Thermally Evaporated InSe/Cu/GaSe Precursors

    Directory of Open Access Journals (Sweden)

    Francis B. Dejene

    2014-01-01

    Full Text Available The relatively small band gap values (~1 eV of CuInSe2 thin films limit the conversion efficiencies of completed CuInSe2/CdS/ZnO solar cell devices. In the case of traditional two-stage growth techniques, limited success has been achieved to homogeneously increase the band gap by substituting indium with gallium. In this study, thermal evaporation of InSe/Cu/Gase precursors was exposed to an elemental Se vapour under defined conditions. This technique produced large-grained, single-phase Cu(In,GaSe2 thin films with a high degree of in-depth compositional uniformity. The selenization temperature, ramp time, reaction period, and the effusion cell temperature with respect to the Cu(In,GaSe2 films were optimized in this study. The homogeneous incorporation of Ga into CuInSe2 led to a systematic shift in the lattice spacing parameters and band gap of the absorber films. Under optimized conditions, gallium in cooperation resulted only in a marginal decrease in the grain size, X-ray diffraction studies confirmed single-phase Cu(In,GaSe2 material, and X-ray photoluminescence spectroscopy in-depth profiling revealed a uniform distribution of the elements through the entire depth of the alloy. From these studies optimum selenization conditions were determined for the deposition of homogeneous Cu(In,GaSe2 thin films with optimum band gap values between 1.01 and 1.21 eV.

  16. study in polymer thin films

    Indian Academy of Sciences (India)

    TECS

    carry out a careful study of steady state conduction of poly- styrene (PS) thin film thermo-electrets sandwiched be- tween metal electrodes both in doped and undoped forms. 2. Experimental. 2.1 Sample preparation. Polystyrene supplied by Polymer Chemical Industry,. Mumbai and naphthalene by S.G. Sisco Pvt Ltd., New ...

  17. Magnetization in permalloy thin films

    Indian Academy of Sciences (India)

    1VES College of Arts, Science and Commerce, Sindhi Society, Chembur, Mumbai 400 071,. India. 2UGC-DAE Consortium for Scientific Research, R5 Shed, ... gas alone, while PNR measurements on 5 and 10% sample show splitting in the spin-up and spin-down reflectivity. Keywords. Permalloy; NiFe thin films; NiFe ...

  18. Low Cost High Performance Zinc Antimonide Thin Films for Thermoelectric Applications

    DEFF Research Database (Denmark)

    Sun, Ye; Christensen, Mogens; Johnsen, Simon

    2012-01-01

    Zinc antimonide thin films with high thermoelectric performance are produced by a simple sputtering method. The phase-pure Zn4Sb3 and ZnSb thin films fulfill the key requirements for commercial TE power generation: cheap elements, cheap fabrication method, high performance and thermal stability...

  19. Optical, electrical and thermoelectric power studies of Al–Sb thin film ...

    Indian Academy of Sciences (India)

    Unknown

    been made to study the bilayer diffusion properties of Al–. Sb thin films. In the present communication, RBS analysis, optical, electrical and thermoelectric power studies of Al–. Sb bilayer structure of thin films prepared by thermal co- evaporation technique is reported. 2. Experimental. Aluminium antimonide films were ...

  20. Influence of thermal treatment in N{sub 2} atmosphere on chemical, microstructural and optical properties of indium tin oxide and nitrogen doped indium tin oxide rf-sputtered thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stroescu, H.; Anastasescu, M.; Preda, S.; Nicolescu, M.; Stoica, M. [Institute of Physical Chemistry “Ilie Murgulescu” of the Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Stefan, N. [National Institute for Lasers, Plasma and Radiation Physics, Atomistilor 409, RO-77125, Bucharest-Magurele (Romania); Kampylafka, V.; Aperathitis, E. [FORTH-IESL, Crete (Greece); Modreanu, M. [Tyndall National Institute, University College Cork, Cork (Ireland); Zaharescu, M. [Institute of Physical Chemistry “Ilie Murgulescu” of the Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Gartner, M., E-mail: mgartner@icf.ro [Institute of Physical Chemistry “Ilie Murgulescu” of the Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania)

    2013-08-31

    We report the influence of the normal thermal treatment (TT) and of rapid thermal annealing (RTA) on the microstructural, optical and electrical properties of indium tin oxide (ITO) and nitrogen doped indium tin oxide (ITO:N) thin films. The TT was carried out for 1 h at 400 °C and the RTA for 1 min up to 400 °C, both in N{sub 2} atmosphere. The ITO and ITO:N films were deposited by reactive sputtering in Argon, and respectively Nitrogen plasma, on Si with (100) and (111) orientation. The present study brings data about the microstructural and optical properties of ITO thin films with thicknesses around 300–400 nm. Atomic Force Microscopy analysis showed the formation of continuous and homogeneous films, fully covered by quasi-spherical shaped particles, with higher roughness values on Si(100) as compared to Si(111). Spectroscopic ellipsometry allowed the determination of film thickness, optical band gap as well as of the dispersion curves of n and k optical constants. X-ray diffraction analysis revealed the presence of diffraction peaks corresponding to the same nominal bulk composition of ITO, but with different intensities and preferential orientation depending on the substrate, atmosphere of deposition and type of thermal treatment. - Highlights: ► Stability of the films can be monitored by experimental ellipsometric spectra. ► The refractive index of indium tin oxide film on 0.3–30 μm range is reported. ► Si(100) substrate induces rougher film surfaces than Si(111). ► Rapid thermal annealing and normal thermal treatment lead to stable conductive film. ► The samples have a higher preferential orientation after rapid thermal annealing.

  1. Properties of RF-Sputtered PZT Thin Films with Ti/Pt Electrodes

    Directory of Open Access Journals (Sweden)

    Cui Yan

    2014-01-01

    Full Text Available Effect of annealing temperature and thin film thickness on properties of Pb(Zr0.53Ti0.47O3 (PZT thin film deposited via radiofrequency magnetron sputtering technique onto Pt/Ti/SiO2/Si substrate was investigated. Average grain sizes of the PZT thin film were measured by atomic force microscope; their preferred orientation was studied through X-ray diffraction analysis. Average residual stress in the thin film was estimated according to the optimized Stoney formula, and impedance spectroscopy characterization was performed via an intelligent LCR measuring instrument. Average grain sizes of PZT thin films were 60 nm~90 nm and their average roughness was less than 2 nm. According to X-ray diffraction analysis, 600°C is the optimal annealing temperature to obtain the PZT thin film with better crystallization. Average residual stress showed that thermal mismatch was the decisive factor of residual stress in Pt/Ti/SiO2/Si substrate; the residual stress in PZT thin film decreased as their thickness increased and increased with annealing temperature. The dielectric constant and loss angle tangent were extremely increased with the thickness of PZT thin films. The capacitance of the device can be adjusted according to the thickness of PZT thin films.

  2. Molecular dynamics simulation of Cu/Au thin films under temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qibin, E-mail: qibinli@cqu.edu.cn [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Chongqing Key Laboratory of Heterogeneous Material Mechanics, Chongqing University, Chongqing 400030 (China); Peng, Xianghe [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Peng, Tiefeng, E-mail: pengtiefeng@cqu.edu.cn [State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400030 (China); Tang, Qizhong [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Zhang, Xiaomin [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China); Chongqing Key Laboratory of Heterogeneous Material Mechanics, Chongqing University, Chongqing 400030 (China); Huang, Cheng [College of Aerospace Engineering, Chongqing University, Chongqing 400030 (China)

    2015-12-01

    Graphical abstract: Heat transportation in the thin films. - Highlights: • The coherent lattice interface is found at thin films after annealing. • The vacancies are observed clearly in the deposit thin films. • The defect and component will influence the energy transportation in the coatings. • The vacancies and lattice mismatch can enlarge the mobility of atoms. • The phonon transportation in thin films has no apparent rule. - Abstract: Three modulation period thin films, 1.8 nm Cu/3.6 nm Au, 2.7 nm Cu/2.7 nm Au and 3.6 nm Cu/1.8 nm Au, are obtained from deposition method and ideal modeling based on lattice constant, to examine their structures and thermophysical characteristics under temperature gradient. The coherent lattice interface is found both at deposit and ideal thin films after annealing. Also, the vacancies are observed clearly in the deposit thin films. The defect and component of thin films will influence the energy transportation in the coatings. The vacancies and lattice mismatch can enlarge the mobility of atoms and result in the failure of coating under the thermal stress. The power spectrum of atoms’ movement has no apparent rule for phonon transportation in thin films. The results are helpful to reveal the micro-mechanism and provide reasonable basis for the failure of metallic coatings.

  3. Tuning of thermally induced first-order semiconductor-to-metal transition in pulsed laser deposited VO2 epitaxial thin films

    Science.gov (United States)

    Behera, Makhes K.; Pradhan, Dhiren K.; Pradhan, Sangram K.; Pradhan, Aswini K.

    2017-12-01

    Vanadium oxide (VO2) thin films have drawn significant research and development interest in recent years because of their intriguing physical origin and wide range of functionalities useful for many potential applications, including infrared imaging, smart windows, and energy and information technologies. However, the growth of highly epitaxial films of VO2, with a sharp and distinct controllable transition, has remained a challenge. Here, we report the structural and electronic properties of high quality and reproducible epitaxial thin films of VO2, grown on c-axis oriented sapphire substrates using pulsed laser deposition at different deposition pressures and temperatures, followed by various annealing schedules. Our results demonstrate that the annealing of epitaxial VO2 films significantly enhances the Semiconductor to Metal Transition (SMT) to that of bulk VO2 transition. The effect of oxygen partial pressure during the growth of VO2 films creates a significant modulation of the SMT from around room temperature to as high as the theoretical value of 68 °C. We obtained a bulk order transition ≥104 while reducing the transition temperature close to 60 °C, which is comparatively less than the theoretical value of 68 °C, demonstrating a clear and drastic improvement in the SMT switching characteristics. The results reported here will open the door to fundamental studies of VO2, along with tuning of the transition temperatures for potential applications for multifunctional devices.

  4. Investigation of physical properties of quaternary AgGa{sub 0.5}In{sub 0.5}Te{sub 2} thin films deposited by thermal evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Karaagac, H. [Department of Physics, Middle East Technical University, 06531 Ankara (Turkey); Parlak, M., E-mail: parlak@metu.edu.t [Department of Physics, Middle East Technical University, 06531 Ankara (Turkey)

    2010-08-06

    The aim of this study is to understand the structural, optical and photo-electrical properties of the quaternary chalcogenide AgGa{sub 0.5}In{sub 0.5}Te{sub 2} thin films deposited onto the glass substrates by thermal evaporation of the single crystalline powder. Energy dispersive X-ray analysis (EDXA) showed remarkable change in atomic percentage of the constituent elements after annealing. The X-ray diffraction (XRD) of the films below the annealing temperature of 300 {sup o}C indicated the polycrystalline structure with co-existence of AgGaTe{sub 2} and AgGa{sub 0.5}In{sub 0.5}Te{sub 2} phases. However, the single phase of AgGa{sub 0.5}In{sub 0.5}Te{sub 2} chalcopyrite structure was obtained at the annealing of 300 {sup o}C. The band gap values were calculated in between 1.05 and 1.37 eV depending on annealing temperature. The temperature dependent photoconductivity was measured under different illumination intensity. The nature of existing trap levels were studied by measuring the variation of photocurrent as a function of illumination intensity. The analysis showed that AgGa{sub 0.5}In{sub 0.5}Te{sub 2} thin film changes its behavior from the sublinear to supralinear photoconductivity after annealing.

  5. The Influence of Temperature on the Formation of Cubic Structured CdO Nanoparticles and Their Thin Films from Bis(2-hydroxy-1-naphthaldehydatocadmium(II Complex via Thermal Decomposition Technique

    Directory of Open Access Journals (Sweden)

    Thokozani Xaba

    2017-01-01

    Full Text Available Recently, researchers have developed a great interest in the synthesis of metal oxide nanoparticles due to their potential applications in various fields of science and industry, especially in catalysis, due to their high activity. Bis(2-hydroxy-1-naphthaldehydatocadmium(II complexes were prepared and used as precursors for the synthesis of cadmium oxide nanoparticles via thermal decomposition method using HDA as a stabilizing agent. The prepared complexes were also used as single source precursors to prepare CdO thin films onto the glass substrates by spin coating and were annealed at 250, 300, and 350°C, respectively. The precursors were characterized by Fourier transform infrared (FTIR spectroscopy, elemental analysis, nuclear magnetic resonance (NMR, and thermogravimetric analysis (TGA. The synthesized CdO nanoparticles and CdO thin films were characterized by ultraviolet-visible (UV-vis spectroscopy, photoluminescence (PL, X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and atomic force microscopy (AFM.

  6. Formation of nanomagnetic thin films by dispersed fullerenes

    Science.gov (United States)

    Zheng, Lingyi A.; Lairson, Bruce M.; Barrera, Enrique V.; Shull, Robert D.

    2000-11-01

    A method of forming magnetic materials using dispersed fullerenes in ferromagnetic materials has been studied. Fullerenes (C60) have been integrated into the matrix of Co, Fe, CoFe thin films by thermal vapor codeposition. The size effects and interaction of the C60 molecules to the metallic atoms promote a self-assembly grain growth mode to produce thin films with unique evoluted microstructures characterized by nanosize columnar grains with uniformly dispersed C60 on the grain boundaries. These nanocrystalline films have displayed a series of promising magnetic properties, such as high out of plane remanence, high coercivity, fast magnetic switching, and unusual hysteresis behavior.

  7. Resistance switching induced by electric fields in manganite thin films

    International Nuclear Information System (INIS)

    Villafuerte, M; Juarez, G; Duhalde, S; Golmar, F; Degreef, C L; Heluani, S P

    2007-01-01

    In this work, we investigate the polarity-dependent Electric Pulses Induced Resistive (EPIR) switching phenomenon in thin films driven by electric pulses. Thin films of 0.5 Ca 0.5 MnO 3 (manganite) were deposited by PLD on Si substrate. The transport properties at the interface between the film and metallic electrode are characterized in order to study the resistance switching. Sample thermal treatment and electrical field history are important to be considered for get reproducible EPIR effect. Carriers trapping at the interfaces are considered as a possible explanation of our results

  8. Dielectric Spectroscopy of Localized Electrical Charges in Ferrite Thin Film

    Science.gov (United States)

    Abdellatif, M. H.; Azab, A. A.; Moustafa, A. M.

    2018-01-01

    A thin film of Gd-doped Mn-Cr ferrite has been prepared by pulsed laser deposition from a bulk sample of the same ferrite prepared by the conventional double sintering ceramic technique. The charge localization and surface conduction in the ferromagnetic thin film were studied. The relaxation of the dielectric dipoles after exposure to an external alternating-current (AC) electric field was investigated. The effect of charge localization on the real and imaginary parts of the dielectric modulus was studied. The charge localization in the thin film was enhanced and thereby the Maxwell-Wagner-type interfacial polarization. The increase in interfacial polarization is a direct result of the enhanced charge localization. The sample was characterized in terms of its AC and direct-current (DC) electrical conductivity, and thermally stimulated discharge current.

  9. Sensing of volatile organic compounds by copper phthalocyanine thin films

    Science.gov (United States)

    Ridhi, R.; Saini, G. S. S.; Tripathi, S. K.

    2017-02-01

    Thin films of copper phthalocyanine have been deposited by thermal evaporation technique. We have subsequently exposed these films to the vapours of methanol, ethanol and propanol. Optical absorption, infrared spectra and electrical conductivities of these films before and after exposure to chemical vapours have been recorded in order to study their sensing mechanisms towards organic vapours. These films exhibit maximum sensing response to methanol while low sensitivities of the films towards ethanol and propanol have been observed. The changes in sensitivities have been correlated with presence of carbon groups in the chemical vapours. The effect of different types of electrodes on response-recovery times of the thin film with organic vapours has been studied and compared. The electrodes gap distance affects the sensitivity as well as response-recovery time values of the thin films.

  10. Preparation of mesoporous silica thin films by photocalcination method and their adsorption abilities for various proteins

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Katsuya, E-mail: katsuya-kato@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Nakamura, Hitomi [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Yamauchi, Yoshihiro; Nakanishi, Kazuma; Tomita, Masahiro [Department of Chemistry for Materials, Graduate School of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8570 (Japan)

    2014-07-01

    Mesoporous silica (MPS) thin film biosensor platforms were established. MPS thin films were prepared from tetraethoxysilane (TEOS) via using sol–gel and spin-coating methods using a poly-(ethylene oxide)-block-poly-(propylene oxide)-block-poly-(ethylene oxide) triblock polymer, such as P123 ((EO){sub 20}(PO){sub 70}(EO){sub 20}) or F127 ((EO){sub 106}(PO){sub 70}(EO){sub 106}), as the structure-directing agent. The MPS thin film prepared using P123 as the mesoporous template and treated via vacuum ultraviolet (VUV) irradiation to remove the triblock copolymer had a more uniform pore array than that of the corresponding film prepared via thermal treatment. Protein adsorption and enzyme-linked immunosorbent assay (ELISA) on the synthesized MPS thin films were also investigated. VUV-irradiated MPS thin films adsorbed a smaller quantity of protein A than the thermally treated films; however, the human immunoglobulin G (IgG) binding efficiency was higher on the former. In addition, protein A–IgG specific binding on MPS thin films was achieved without using a blocking reagent; i.e., nonspecific adsorption was inhibited by the uniform pore arrays of the films. Furthermore, VUV-irradiated MPS thin films exhibited high sensitivity for ELISA testing, and cytochrome c adsorbed on the MPS thin films exhibited high catalytic activity and recyclability. These results suggest that MPS thin films are attractive platforms for the development of novel biosensors. - Highlights: • VUV-treated MPS thin films with removed polymer had uniform pore. • VUV-treated MPS thin films exhibited high sensitivity by ELISA. • Cytochrome c showed the catalytic activity and recyclability on synthesized films.

  11. Antireflecting sublayers for neutron thin film polarising mirrors

    International Nuclear Information System (INIS)

    Childs, F.; Penfold, J.; Williams, W.G.

    1981-09-01

    Measurements of the neutron polarising capability of Iron/Cobalt thin film mirrors deposited onto various Gadolinium-rich antireflecting sublayers are presented and the results compared with theoretical predictions. Excellent results were obtained in the cold neutron region though a degradation in performance is predicted in the thermal region at wavelengths approximately 1A. (author)

  12. Low temperature thin films for next-generation microelectronics (invited)

    NARCIS (Netherlands)

    Schmitz, Jurriaan

    2017-01-01

    In this article the current methodologies for low-temperature thin film deposition in microelectronics are reviewed. The paper discusses the high temperature processes in microchip manufacturing and describes the thermal budget fitting issue. The quest for low temperature deposition techniques is

  13. Thin-film resistance thermometers on silicon wafers

    International Nuclear Information System (INIS)

    Kreider, Kenneth G; Ripple, Dean C; Kimes, William A

    2009-01-01

    We have fabricated Pt thin-film resistors directly sputtered on silicon substrates to evaluate their use as resistance thermal detectors (RTDs). This technique was chosen to achieve more accurate temperature measurements of large silicon wafers during semiconductor processing. High-purity (0.999 968 mass fraction) platinum was sputter deposited on silicon test coupons using titanium and zirconium bond coats. These test coupons were annealed, and four-point resistance specimens were prepared for thermal evaluation. Their response was compared with calibrated platinum–palladium thermocouples in a tube furnace. We evaluated the effects of furnace atmosphere, thin-film thickness, bond coats, annealing temperature and peak thermal excursion of the Pt thin films. Secondary ion mass spectrometry (SIMS) was performed to evaluate the effect of impurities on the thermal resistance coefficient, α. We present typical resistance versus temperature curves, hysteresis plots versus temperature and an analysis of the causes of uncertainties in the measurement of seven test coupons. We conclude that sputtered thin-film platinum resistors on silicon wafers can yield temperature measurements with uncertainties of less than 1 °C, k = 1 up to 600 °C. This is comparable to or better than commercially available techniques

  14. Thin films of soft matter

    CERN Document Server

    Kalliadasis, Serafim

    2007-01-01

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

  15. Thin-Film Power Transformers

    Science.gov (United States)

    Katti, Romney R.

    1995-01-01

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

  16. Ta-based amorphous metal thin films

    Energy Technology Data Exchange (ETDEWEB)

    McGlone, John M., E-mail: mcglone@eecs.oregonstate.edu [School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331-5501 (United States); Olsen, Kristopher R. [Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003 (United States); Stickle, William F.; Abbott, James E.; Pugliese, Roberto A.; Long, Greg S. [Hewlett-Packard Company, Corvallis, OR, 97333 (United States); Keszler, Douglas A. [Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003 (United States); Wager, John F. [School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331-5501 (United States)

    2015-11-25

    With their lack of grains and grain boundaries, amorphous metals are known to possess advantageous mechanical properties and enhanced chemical stability relative to crystalline metals. Commonly, however, they exhibit poor high-temperature stability because of their metastable nature. Here, we describe two new Ta-based ternary metal thin films that retain thermal stability to 600 °C and above. The new thin-film compositions, Ta{sub 2}Ni{sub 2}Si{sub 1} and Ta{sub 2}Mo{sub 2}Si{sub 1}, are amorphous, exhibiting ultra-smooth surfaces (<0.4 nm) and resistivities typical of amorphous metals (224 and 177 μΩ cm, respectively). - Highlights: • New Ta-based amorphous metals were sputter deposited from individual targets. • As-deposited amorphous structure was confirmed through diffraction techniques. • Electrical and surface properties were characterized and possess smooth surfaces. • No evidence of crystallization up to 600 °C (TaNiSi) and 800 °C (TaMoSi). • Ultra-smooth surfaces remained unchanged up to crystallization temperature.

  17. A dynamic rheological model for thin-film lubrication

    International Nuclear Information System (INIS)

    Zhang Xiang-Jun; Huang Ying; Guo Yan-Bao; Tian Yu; Meng Yong-Gang

    2013-01-01

    In this study, the effects of the non-Newtonian rheological properties of the lubricant in a thin-film lubrication regime between smooth surfaces were investigated. The thin-film lubrication regime typically appears in Stribeck curves with a clearly observable minimum coefficient of friction (COF) and a low-COF region, which is desired for its lower energy dissipation. A dynamic rheology of the lubricant from the hydrodynamic lubrication regime to the thin-film lubrication regime was proposed based on the convected Maxwell constitutive equation. This rheology model includes the increased relaxation time and the yield stress of the confined lubricant thin film, as well as their dependences on the lubricant film thickness. The Deborah number (De number) was adopted to describe the liquid-solid transition of the confined lubricant thin film under shearing. Then a series of Stribeck curves were calculated based on Tichy's extended lubrication equations with a perturbation of the De number. The results show that the minimum COF points in the Stribeck curve correspond to a critical De number of 1.0, indicating a liquid-to-solid transition of the confined lubricant film. Furthermore, the two proposed parameters in the dynamic rheological model, namely negative slipping length b (indicating the lubricant interfacial effect) and the characteristic relaxation time λ 0 , were found to determine the minimum COF and the width of the low-COF region, both of which were required to optimize the shape of the Stribeck curve. The developed dynamic rheological model interprets the correlation between the rheological and interfacial properties of lubricant and its lubrication behavior in the thin-film regime. (condensed matter: structural, mechanical, and thermal properties)

  18. Thermoanalytical study of the decomposition of yttrium trifluoroacetate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Eloussifi, H. [GRMT, GRMT, Department of Physics, University of Girona, Campus Montilivi, E17071 Girona, Catalonia (Spain); Laboratoire de Chimie Inorganique, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000 Sfax (Tunisia); Farjas, J., E-mail: jordi.farjas@udg.cat [GRMT, GRMT, Department of Physics, University of Girona, Campus Montilivi, E17071 Girona, Catalonia (Spain); Roura, P. [GRMT, GRMT, Department of Physics, University of Girona, Campus Montilivi, E17071 Girona, Catalonia (Spain); Ricart, S.; Puig, T.; Obradors, X. [Institut de Ciència de Materials de Barcelona (CSIC), Campus UAB, 08193 Bellaterra, Catalonia (Spain); Dammak, M. [Laboratoire de Chimie Inorganique, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000 Sfax (Tunisia)

    2013-10-31

    We present the use of the thermal analysis techniques to study yttrium trifluoroacetate thin films decomposition. In situ analysis was done by means of thermogravimetry, differential thermal analysis, and evolved gas analysis. Solid residues at different stages and the final product have been characterized by X-ray diffraction and scanning electron microscopy. The thermal decomposition of yttrium trifluoroacetate thin films results in the formation of yttria and presents the same succession of intermediates than powder's decomposition, however, yttria and all intermediates but YF{sub 3} appear at significantly lower temperatures. We also observe a dependence on the water partial pressure that was not observed in the decomposition of yttrium trifluoroacetate powders. Finally, a dependence on the substrate chemical composition is discerned. - Highlights: • Thermal decomposition of yttrium trifluoroacetate films. • Very different behavior of films with respect to powders. • Decomposition is enhanced in films. • Application of thermal analysis to chemical solution deposition synthesis of films.

  19. Thermoanalytical study of the decomposition of yttrium trifluoroacetate thin films

    International Nuclear Information System (INIS)

    Eloussifi, H.; Farjas, J.; Roura, P.; Ricart, S.; Puig, T.; Obradors, X.; Dammak, M.

    2013-01-01

    We present the use of the thermal analysis techniques to study yttrium trifluoroacetate thin films decomposition. In situ analysis was done by means of thermogravimetry, differential thermal analysis, and evolved gas analysis. Solid residues at different stages and the final product have been characterized by X-ray diffraction and scanning electron microscopy. The thermal decomposition of yttrium trifluoroacetate thin films results in the formation of yttria and presents the same succession of intermediates than powder's decomposition, however, yttria and all intermediates but YF 3 appear at significantly lower temperatures. We also observe a dependence on the water partial pressure that was not observed in the decomposition of yttrium trifluoroacetate powders. Finally, a dependence on the substrate chemical composition is discerned. - Highlights: • Thermal decomposition of yttrium trifluoroacetate films. • Very different behavior of films with respect to powders. • Decomposition is enhanced in films. • Application of thermal analysis to chemical solution deposition synthesis of films

  20. Structural and thermal characterization of La5Ca9Cu24O41 thin films grown by pulsed laser deposition on (1 1 0) SrTiO3 substrates

    International Nuclear Information System (INIS)

    Svoukis, E.; Athanasopoulos, G.I.; Altantzis, Th.; Lioutas, Ch.; Martin, R.S.; Revcolevschi, A.; Giapintzakis, J.

    2012-01-01

    In the present study stoichiometric, b-axis oriented La 5 Ca 9 Cu 24 O 41 thin films were grown by pulsed laser deposition on (1 1 0) SrTiO 3 substrates in the temperature range 600–750 °C. High resolution transmission electron microscopy was employed to investigate the growth mechanism and the epitaxial relationship between the SrTiO 3 substrates and the La 5 Ca 9 Cu 24 O 41 films grown at 700 °C. The 3-ω method was used to measure the cross-plane thermal conductivity of La 5 Ca 9 Cu 24 O 41 films in the temperature range 50–350 K. The observed glass-like behavior is attributed to atomic-scale defects, grain boundaries and an interfacial layer formed between film and substrate.

  1. Morphology reliance of cobalt sulfide thin films: A chemo-thermo-mechanical perception

    Energy Technology Data Exchange (ETDEWEB)

    Kamble, S.S. [Thin Film & Solar Studies Research Laboratory, Solapur University, Solapur 413 255, M.S. (India); Sikora, A. [Electrotechnical Institute, Division of Electrotechnology & Materials Science, ul. M Skłodowskiej-Curie 55/61, 50-369 Wroclaw (Poland); Pawar, S.T. [Thin Film & Solar Studies Research Laboratory, Solapur University, Solapur 413 255, M.S. (India); Kambale, R.C. [Department of Physics, University of Pune, Ganeshkhind, Pune 411 007, M.S. (India); Maldar, N.N. [School of Chemical Sciences, Solapur University, Solapur 413 255, M.S. (India); Deshmukh, L.P., E-mail: laldeshmukh@gmail.com [Thin Film & Solar Studies Research Laboratory, Solapur University, Solapur 413 255, M.S. (India)

    2015-05-15

    Highlights: • Optimized heterogeneous growth process for the deposition of CoS thin films. • As-obtained CoS thin films exhibit hexagonal crystal structure. • Optimized CoS thin films were Co{sup 2+} rich in nature. • Magnetic force microscopy revealed randomly scattered magnetic constellations. - Abstract: We report onto the morphology dependency of CoS thin films by studying the role of mechanical agitation, thermal assistance and deposition duration in an aqueous alkaline bath (pH = 9 ± 0.1). The deposition of CoS thin films was carried out at different mechanical stirring rates, deposition temperatures and times. As-optimized CoS thin film were of polycrystalline nature and exhibited hexagonal crystal structure. Co{sup 2+} rich nature (≈85%) of optimistically grown thin film was detected. Complex multifaceted webbed network of as-grown elongated and threaded into each other CoS crystals was observed through a scanning electron microscope. Surface morphology was further studied by means of an atomic force microscopy. Existence of magnetic domains was marked in the magnetic force microscopy. As-grown CoS thin films were having transmission index of 0.5 with a band gap of ≈1.59 eV.

  2. Non-linear optics of nano-scale pentacene thin film

    Science.gov (United States)

    Yahia, I. S.; Alfaify, S.; Jilani, Asim; Abdel-wahab, M. Sh.; Al-Ghamdi, Attieh A.; Abutalib, M. M.; Al-Bassam, A.; El-Naggar, A. M.

    2016-07-01

    We have found the new ways to investigate the linear/non-linear optical properties of nanostructure pentacene thin film deposited by thermal evaporation technique. Pentacene is the key material in organic semiconductor technology. The existence of nano-structured thin film was confirmed by atomic force microscopy and X-ray diffraction. The wavelength-dependent transmittance and reflectance were calculated to observe the optical behavior of the pentacene thin film. It has been observed the anomalous dispersion at wavelength λ 800. The non-linear refractive index of the deposited films was investigated. The linear optical susceptibility of pentacene thin film was calculated, and we observed the non-linear optical susceptibility of pentacene thin film at about 6 × 10-13 esu. The advantage of this work is to use of spectroscopic method to calculate the liner and non-liner optical response of pentacene thin films rather than expensive Z-scan. The calculated optical behavior of the pentacene thin films could be used in the organic thin films base advanced optoelectronic devices such as telecommunications devices.

  3. Fabrication of Pb (Zr, Ti) O3 Thin Film for Non-Volatile Memory Device Application

    International Nuclear Information System (INIS)

    Mar Lar Win

    2011-12-01

    Ferroelectric lead zirconate titanate powder was composed of mainly the oxides of titanium, zirconium and lead. PZT powder was firstly prepared by thermal synthesis at different Zr/Ti ratios with various sintering temperatures. PZT thin film was fabricated on SiO2/Si substrate by using thermal evaporation method. Physical and elemental analysis were carried out by using SEM, EDX and XRD The ferroelectric properties and the switching behaviour of the PZT thin films were investigated. The ferroelectric properties and switching properties of the PZT thin film (near morphotropic phase boundary sintered at 800 C) could function as a nonvolatile memory.

  4. Organic Thin Films for Photonics Applications

    National Research Council Canada - National Science Library

    Thorner, John

    1999-01-01

    The Organic Thin Films for Photonics Applications Topical Meeting provided an interdisciplinary forum for the presentation and discussion of new and previously unpublished results on advanced organic...

  5. Beryllium thin films for resistor applications

    Science.gov (United States)

    Fiet, O.

    1972-01-01

    Beryllium thin films have a protective oxidation resistant property at high temperature and high recrystallization temperature. However, the experimental film has very low temperature coefficient of resistance.

  6. Analysis of Hard Thin Film Coating

    Science.gov (United States)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  7. Thin films for emerging applications v.16

    CERN Document Server

    Francombe, Maurice H

    1992-01-01

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

  8. Minerals deposited as thin films

    International Nuclear Information System (INIS)

    Vazquez, Cristina; Leyt, D.V. de; Custo, Graciela

    1987-01-01

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

  9. Heavily-doped ZnO:Al thin films prepared by using magnetron Co-sputtering: Optical and electrical properties

    Science.gov (United States)

    Moon, Eun-A.; Jun, Young-Kil; Kim, Nam-Hoon; Lee, Woo-Sun

    2016-07-01

    Photovoltaic applications require transparent conducting-oxide (TCO) thin films with high optical transmittance in the visible spectral region (380 - 780 nm), low resistivity, and high thermal/chemical stability. The ZnO thin film is one of the most common alternatives to the conventional indium-tin-oxide (ITO) thin film TCO. Highly transparent and conductive ZnO thin films can be prepared by doping with group III elements. Heavily-doped ZnO:Al (AZO) thin films were prepared by using the RF magnetron co-sputtering method with ZnO and Al targets to obtain better characteristics at a low cost. The RF sputtering power to each target was varied to control the doping concentration in fixed-thickness AZO thin films. The crystal structures of the AZO thin films were analyzed by using X-ray diffraction. The morphological microstructure was observed by using scanning electron microscopy. The optical transmittance and the band gap energy of the AZO thin films were examined with an UV-visible spectrophotometer in the range of 300 - 1800 nm. The resistivity and the carrier concentration were examined by using a Hall-effect measurement system. An excellent optical transmittance > 80% with an appropriate band gap energy (3.26 - 3.27 eV) and an improved resistivity (~10 -1 Ω·cm) with high carrier concentration (1017 - 1019 cm -3) were demonstrated in 350-nm-thick AZO thin films for thin-film photovoltaic applications.

  10. Superconducting fluctuations in molybdenum nitride thin films

    Science.gov (United States)

    Baskaran, R.; Thanikai Arasu, A. V.; Amaladass, E. P.; Vaidhyanathan, L. S.; Baisnab, D. K.

    2018-02-01

    MoN thin films have been deposited using reactive sputtering. The change in resistance near superconducting transition temperature at various magnetic fields has been analyzed based on superconducting fluctuations in the system. The Aslamazov and Larkin scaling theory has been utilized to analyze the conductance change. The results indicate that most of the measurements show two dimensional (2D) nature and exhibit scaling behavior at lower magnetic fields (7T). We have also analyzed our data based on the model in which there is no explicit dependence of Tc. These analyses also substantiate a crossover from a 2D nature to a 3D at larger fields. Analysis using lowest Landau level scaling theory for a 2D system exhibit scaling behavior and substantiate our observations. The broadening at low resistance part has been explained based on thermally activated flux flow model and show universal behavior. The dependence of Uo on magnetic field indicates both single and collective vortex behavior.

  11. Study on the Humidity Susceptibility of Thin-Film CIGS Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Pern, F. J.; Egaas, B.; To, B.; Jiang, C. S.; Li, J. V.; Glynn, S.; DeHart, C.

    2010-01-01

    The report summarizes the research on the susceptibility of a thermally co-evaporated CuInGaSe2 (CIGS) thin-film absorber to humidity and its consequence on composition, morphology, electrical and electronic properties, and device efficiency.

  12. Fabrication and testing of thermoelectric thin film devices

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, A.V.; Foreman, R.J.; Summers, L.J.; Barbee, T.W. Jr.; Farmer, J.C. [Lawrence Livermore National Lab., CA (United States). Chemistry and Materials Science Dept.

    1996-03-01

    Two thin-film thermoelectric devices are experimentally demonstrated. The relevant thermal loads on the cold junction of these devices are determined. The analytical form of the equation that describes the thermal loading of the device enables one to model the performance based on the independently measured electronic properties of the films forming the devices. This model elucidates which parameters determine device performance, and how they can be used to maximize performance.

  13. Dielectric loss of strontium titanate thin films

    Science.gov (United States)

    Dalberth, Mark Joseph

    1999-12-01

    Interest in strontium titanate (STO) thin films for microwave device applications continues to grow, fueled by the telecommunications industry's interest in phase shifters and tunable filters. The optimization of these devices depends upon increasing the phase or frequency tuning and decreasing the losses in the films. Currently, the dielectric response of thin film STO is poorly understood through lack of data and a theory to describe it. We have studied the growth of STO using pulsed laser deposition and single crystal substrates like lanthanum aluminate and neodymium gallate. We have researched ways to use ring resonators to accurately measure the dielectric response as a function of temperature, electric field, and frequency from low radio frequencies to a few gigahertz. Our films grown on lanthanum aluminate show marked frequency dispersion in the real part of the dielectric constant and hints of thermally activated loss behavior. We also found that films grown with conditions that optimized the dielectric constant showed increased losses. In an attempt to simplify the system, we developed a technique called epitaxial lift off, which has allowed us to study films removed from their growth substrates. These free standing films have low losses and show obvious thermally activated behavior. The "amount of tuning," as measured by a figure of merit, KE, is greater in these films than in the films still attached to their growth substrates. We have developed a theory that describes the real and imaginary parts of the dielectric constant. The theory models the real part using a mean field description of the ionic motion in the crystal and includes the loss by incorporating the motion of charged defects in the films.

  14. The Influence of the Composition of Ru100−xAlx (x = 50, 55, 60, 67 Thin Films on Their Thermal Stability

    Directory of Open Access Journals (Sweden)

    Marietta Seifert

    2017-03-01

    Full Text Available RuAl thin films possess a high potential as a high temperature stable metallization for surface acoustic wave devices. During the annealing process of the Ru-Al films, Al 2 O 3 is formed at the surface of the films even under high vacuum conditions, so that the composition of a deposited Ru 50 Al 50 film is shifted to a Ru-rich alloy. To compensate for this effect, the Al content is systematically increased during the deposition of the Ru-Al films. Three Al-rich alloys—Ru 45 Al 55 , Ru 40 Al 60 and Ru 33 Al 67 —were analyzed concerning their behavior after high temperature treatment under high vacuum and air conditions in comparison to the initial Ru 50 Al 50 sample. Although the films’ cross sections show a more homogeneous structure in the case of the Al-rich films, the RuAl phase formation is reduced with increasing Al content.

  15. Post-annealing effects on pulsed laser deposition-grown GaN thin films

    International Nuclear Information System (INIS)

    Cheng, Yu-Wen; Wu, Hao-Yu; Lin, Yu-Zhong; Lee, Cheng-Che; Lin, Ching-Fuh

    2015-01-01

    In this work, the post-annealing effects on gallium nitride (GaN) thin films grown from pulsed laser deposition (PLD) are investigated. The as-deposited GaN thin films grown from PLD are annealed at different temperatures in nitrogen ambient. Significant changes of the GaN crystal properties are observed. Raman spectroscopy is used to observe the crystallinity, the change of residual stress, and the thermal decomposition of the annealed GaN thin films. X-ray diffraction is also applied to identify the crystal phase of GaN thin films, and the surface morphology of GaN thin films annealed at different temperatures is observed by scanning electron microscopy. Through the above analyses, the GaN thin films grown by PLD undergo three stages: phase transition, stress alteration, and thermal decomposition. At a low annealing temperature, the rock salt GaN in GaN films is transformed into wurtzite. The rock salt GaN diminishes with increasing annealing temperature. At a medium annealing temperature, the residual stress of the film changes significantly from compressive strain to tensile strain. As the annealing temperature further increases, the GaN undergoes thermal decomposition and the surface becomes granular. By investigating the annealing temperature effects and controlling the optimized annealing temperature of the GaN thin films, we are able to obtain highly crystalline and strain-free GaN thin films by PLD. - Highlights: • The GaN thin film is grown on sapphire by pulsed laser deposition. • The GaN film undergoes three stages with increasing annealing temperature. • In the first stage, the film transfers from rock salt to wurtzite phase. • In the second stage, the stress in film changes from compressive to tensile. • In the final stage, the film thermally decomposes and becomes granular

  16. Cubic erbium trihydride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Adams, D.P., E-mail: dpadams@sandia.gov; Rodriguez, M.A.; Romero, J.A.; Kotula, P.G.; Banks, J.

    2012-07-31

    High-purity, erbium hydride thin films have been deposited onto {alpha}-Al{sub 2}O{sub 3} and oxidized Si by reactive sputtering methods. Rutherford backscattering spectrometry and elastic recoil detection show that films deposited at temperatures of 35, 150 and 275 Degree-Sign C have a composition of 3H:1Er. Erbium trihydride films consist of a face-centered cubic erbium sub-lattice with a lattice parameter in the range of 5.11-5.20 A. The formation of cubic ErH{sub 3} is intriguing, because previous studies demonstrate a single trihydride phase with a hexagonal metal sub-lattice. The formation of a stable, cubic trihydride phase is attributed to a large, in-plane stress resulting from ion beam sputter deposition. - Highlights: Black-Right-Pointing-Pointer Cubic erbium trihydride thin films produced by ion beam sputter deposition. Black-Right-Pointing-Pointer Face-centered cubic metal sub-lattice verified by X-ray and electron diffraction. Black-Right-Pointing-Pointer Composition evaluated using four different techniques. Black-Right-Pointing-Pointer Film stress monitored during deposition. Black-Right-Pointing-Pointer Formation of cubic erbium trihydride attributed to a large, in-plane film stress.

  17. Flexible thin film magnetoimpedance sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kurlyandskaya, G.V., E-mail: galina@we.lc.ehu.es [Universidad del País Vasco, UPV/EHU, Departamento de Electricidad y Electrónica, P.O. Box 644, Bilbao 48080 (Spain); Ural Federal University, Laboratory of Magnetic sensoric, Lenin Ave. 51, 620083 Ekaterinburg (Russian Federation); Fernández, E. [BCMaterials UPV-EHU, Vizcaya Science and Technology Park, 48160 Derio (Spain); Svalov, A. [Universidad del País Vasco, UPV/EHU, Departamento de Electricidad y Electrónica, P.O. Box 644, Bilbao 48080 (Spain); Ural Federal University, Laboratory of Magnetic sensoric, Lenin Ave. 51, 620083 Ekaterinburg (Russian Federation); Burgoa Beitia, A. [Universidad del País Vasco, UPV/EHU, Departamento de Electricidad y Electrónica, P.O. Box 644, Bilbao 48080 (Spain); García-Arribas, A. [Universidad del País Vasco, UPV/EHU, Departamento de Electricidad y Electrónica, P.O. Box 644, Bilbao 48080 (Spain); BCMaterials UPV-EHU, Vizcaya Science and Technology Park, 48160 Derio (Spain); Larrañaga, A. [SGIker, Servicios Generales de Investigación, Universidad del País Vasco (UPV/EHU), 48080 Bilbao (Spain)

    2016-10-01

    Magnetically soft thin film deposited onto polymer substrates is an attractive option for flexible electronics including magnetoimpedance (MI) applications. MI FeNi/Ti based thin film sensitive elements were designed and prepared using the sputtering technique by deposition onto rigid and flexible substrates at different deposition rates. Their structure, magnetic properties and MI were comparatively analyzed. The main structural features were sufficiently accurately reproduced in the case of deposition onto cyclo olefine polymer substrates compared to glass substrates for the same conditions. Although for the best condition (28 nm/min rate) of the deposition onto polymer a significant reduction of the MI field sensitivity was found satisfactory for sensor applications sensitivity: 45%/Oe was obtained for a frequency of 60 MHz. - Highlights: • [FeNi/Ti]{sub 3}/Cu/[FeNi/Ti]{sub 3} films were prepared by sputtering at different deposition rates. • Polymer substrates insure sufficiently accurate reproducibility of the film structure. • High deposition rate of 28 nm/min insures the highest values of the magnetoimpedance sensitivity. • Deposition onto polymer results in the satisfactory magnetoimpedance sensitivity of 45%/Oe.

  18. Flexible thin film magnetoimpedance sensors

    International Nuclear Information System (INIS)

    Kurlyandskaya, G.V.; Fernández, E.; Svalov, A.; Burgoa Beitia, A.; García-Arribas, A.; Larrañaga, A.

    2016-01-01

    Magnetically soft thin film deposited onto polymer substrates is an attractive option for flexible electronics including magnetoimpedance (MI) applications. MI FeNi/Ti based thin film sensitive elements were designed and prepared using the sputtering technique by deposition onto rigid and flexible substrates at different deposition rates. Their structure, magnetic properties and MI were comparatively analyzed. The main structural features were sufficiently accurately reproduced in the case of deposition onto cyclo olefine polymer substrates compared to glass substrates for the same conditions. Although for the best condition (28 nm/min rate) of the deposition onto polymer a significant reduction of the MI field sensitivity was found satisfactory for sensor applications sensitivity: 45%/Oe was obtained for a frequency of 60 MHz. - Highlights: • [FeNi/Ti] 3 /Cu/[FeNi/Ti] 3 films were prepared by sputtering at different deposition rates. • Polymer substrates insure sufficiently accurate reproducibility of the film structure. • High deposition rate of 28 nm/min insures the highest values of the magnetoimpedance sensitivity. • Deposition onto polymer results in the satisfactory magnetoimpedance sensitivity of 45%/Oe.

  19. Thin Film Composite Membranes: Mechanical and Antifouling Properties

    Directory of Open Access Journals (Sweden)

    Kassim Shaari Norin Zamiah

    2017-01-01

    Full Text Available As compared to membranes produced from pure polymer or pure inorganic materials, a hybrid membrane possesses better mechanical and thermal properties. This paper reported on the effect of incorporating silica nano-precursor (tetraethylorthosilicate as well as glycerol in the formulation of hybrid membrane on the mechanical properties and antifouling properties of the resultant thin film composite membranes. The mechanical properties were measured in terms of tensile strength, tensile strain and elastic modulus. Whereas for antifouling properties, it was evaluated through the measurements of relative flux decay (RFD and relative flux recovery (RFR, along with the permeate flux rate, percentage glycerol permeated and NaCl rejection. Results showed that the presence of silica and glycerol in hybrid membrane’s formulation had increased the tensile strength and elongation of the resultant membranes. In addition to that, the incorporation of glycerol has resulted in thin film composite with better antifouling properties as compared to the thin film composite with barrier layer from the pure polymer blend. Based on its performance, the fabricated thin film composite has a great potential to be used as a pathway for crude glycerol purification due to some advantages over the existing process that employ membrane.

  20. Metallic and Ceramic Thin Film Thermocouples for Gas Turbine Engines

    Directory of Open Access Journals (Sweden)

    Otto J. Gregory

    2013-11-01

    Full Text Available Temperatures of hot section components in today’s gas turbine engines reach as high as 1,500 °C, making in situ monitoring of the severe temperature gradients within the engine rather difficult. Therefore, there is a need to develop instrumentation (i.e., thermocouples and strain gauges for these turbine engines that can survive these harsh environments. Refractory metal and ceramic thin film thermocouples are well suited for this task since they have excellent chemical and electrical stability at high temperatures in oxidizing atmospheres, they are compatible with thermal barrier coatings commonly employed in today’s engines, they have greater sensitivity than conventional wire thermocouples, and they are non-invasive to combustion aerodynamics in the engine. Thin film thermocouples based on platinum:palladium and indium oxynitride:indium tin oxynitride as well as their oxide counterparts have been developed for this purpose and have proven to be more stable than conventional type-S and type-K thin film thermocouples. The metallic and ceramic thin film thermocouples described within this paper exhibited remarkable stability and drift rates similar to bulk (wire thermocouples.

  1. P-type CuxS thin films: Integration in a thin film transistor structure

    International Nuclear Information System (INIS)

    Nunes de Carvalho, C.; Parreira, P.; Lavareda, G.; Brogueira, P.; Amaral, A.

    2013-01-01

    Cu x S thin films, 80 nm thick, are deposited by vacuum thermal evaporation of sulfur-rich powder mixture, Cu 2 S:S (50:50 wt.%) with no intentional heating of the substrate. The process of deposition occurs at very low deposition rates (0.1–0.3 nm/s) to avoid the formation of Cu or S-rich films. The evolution of Cu x S films surface properties (morphology/roughness) under post deposition mild annealing in air at 270 °C and their integration in a thin film transistor (TFT) are the main objectives of this study. Accordingly, Scanning Electron Microscopy studies show Cu x S films with different surface morphologies, depending on the post deposition annealing conditions. For the shortest annealing time, the Cu x S films look to be constructed of grains with large dimension at the surface (approximately 100 nm) and consequently, irregular shape. For the longest annealing time, films with a fine-grained surface are found, with some randomly distributed large particles bound to this fine-grained surface. Atomic Force Microscopy results indicate an increase of the root-mean-square roughness of Cu x S surface with annealing time, from 13.6 up to 37.4 nm, for 255 and 345 s, respectively. The preliminary integration of Cu x S films in a TFT bottom-gate type structure allowed the study of the feasibility and compatibility of this material with the remaining stages of a TFT fabrication as well as the determination of the p-type characteristic of the Cu x S material. - Highlights: • Surface properties of annealed Cu x S films. • Variation of conductivity with annealing temperatures of Cu x S films. • Application of evaporated Cu x S films in a thin film transistor (TFT) structure. • Determination of Cu x S p-type characteristic from TFT behaviour

  2. Pulse electrodeposition of Prussian Blue thin films

    International Nuclear Information System (INIS)

    Najafisayar, P.; Bahrololoom, M.E.

    2013-01-01

    The effects of pulse electrodeposition parameters like peak current density and frequency on the electrochemical properties of Prussian Blue thin films were investigated. Electrochemical Impedance Spectroscopy, Cyclic Voltammetry and Chronoamperometry tests were carried out on Prussian Blue thin films which were pulse electrodeposited on Indium Tin Oxide coated glass substrates. The results showed that increase in the peak current densities and using higher pulsating frequencies during electrodeposition decreases the charge transfer resistance of the thin films while the diffusion coefficient of electroactive species in the films is increased as a consequence of using the same pulsating parameters. In addition, pulse electrodeposition technique does not alter deposition mechanism and morphology of the Prussian Blue thin films. - Highlights: • Prussian Blue thin films were pulse electrodeposited onto the ITO coated glass. • Pulse current condition affected thin films' electrochemical properties. • High pulsating current and frequency lower thin films' charge transfer resistance. • High pulsating current and frequency increase diffusion coefficient in thin films

  3. Excimer Laser Deposition of PLZT Thin Films

    National Research Council Canada - National Science Library

    Petersen, GAry

    1991-01-01

    .... In order to integrate these devices into optical systems, the production of high quality thin films with high transparency and perovskite crystal structure is desired. This requires development of deposition technologies to overcome the challenges of depositing and processing PLZT thin films.

  4. Permalloy Thin-film Magnetic Sensors

    NARCIS (Netherlands)

    Groenland, J.P.J.; Eijkel, C.J.M.; Fluitman, J.H.J.; de Ridder, R.M.

    1992-01-01

    An introduction to the theory of the anisotropic magnetoresistance effect in ferromagnetic thin films is given, ending in a treatment of the minimalization of the free energy which is the result of the intrinsic and extrinsic anisotropies of the thin-film structure. The anisotropic magnetoresistance

  5. Characterization of nanocrystalline cadmium telluride thin films ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Structural, electrical and optical characteristics of CdTe thin films prepared by a chemical deposi- tion method, successive ionic layer adsorption and reaction (SILAR), are described. For deposition of CdTe thin films, cadmium acetate was used as cationic and sodium tellurite as anionic precursor in aqueous me-.

  6. Characterization of nanocrystalline cadmium telluride thin films ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 29; Issue 2. Characterization of nanocrystalline ... Structural, electrical and optical characteristics of CdTe thin films prepared by a chemical deposition method, successive ionic layer adsorption and reaction (SILAR), are described. For deposition of CdTe thin films, ...

  7. XRD total scattering of the CZTS nanoparticle absorber layer for the thin film solar cells

    DEFF Research Database (Denmark)

    Symonowicz, Joanna; Jensen, Kirsten M. Ø.; Engberg, Sara Lena Josefin

    to revolutionize the solar energy market. However, to commercialize CZTS nanoparticle thin films, the efficiency issues must yet be resolved. In order to do so, it is vital to understand in detail their nanoscale atomic structure. CZTS crystallize in the kesterite structure, where Cu and Zn is distributed between......Cu2ZnSnS4 (CZTS) thin film solar cells are cheap, non-toxic and present an efficiency up to 9,2% [1]. They can be easily manufactured by the deposition of the nanoparticle ink as a thin film followed by a thermal treatment to obtain large grains [2]. Therefore, CZTS has the potential...

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

    International Nuclear Information System (INIS)

    Krockenberger, Y.

    2006-01-01

    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.)

  9. Optical characterization of a-Si:H thin films grown by Hg-Photo-CVD

    International Nuclear Information System (INIS)

    Barhdadi, A.; Karbal, S.; M'Gafad, N.; Benmakhlouf, A.; Chafik El Idrissi, M.; Aka, B.M.

    2006-08-01

    Mercury-Sensitized Photo-Assisted Chemical Vapor Deposition (Hg-Photo-CVD) technique opens new possibilities for reducing thin film growth temperature and producing novel semiconductor materials suitable for the future generation of high efficiency thin film solar cells onto low cost flexible plastic substrates. This paper provides some experimental data resulting from the optical characterization of hydrogenated amorphous silicon thin films grown by this deposition technique. Experiments have been performed on both as-deposited layers and thermal annealed ones. (author) [fr

  10. 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.)

  11. Raman spectroscopy of optical properties in CdS thin films

    Directory of Open Access Journals (Sweden)

    Trajić J.

    2015-01-01

    Full Text Available Properties of CdS thin films were investigated applying atomic force microscopy (AFM and Raman spectroscopy. CdS thin films were prepared by using thermal evaporation technique under base pressure 2 x 10-5 torr. The quality of these films was investigated by AFM spectroscopy. We apply Raman scattering to investigate optical properties of CdS thin films, and reveal existence of surface optical phonon (SOP mode at 297 cm-1. Effective permittivity of mixture were modeled by Maxwell - Garnet approximation. [Projekat Ministarstva nauke Republike Srbije, br. 45003

  12. Supramolecular structure of a perylene derivative in thin films made by vacuum thermal evaporation; Estrutura supramolecular de um derivado de perileno em filmes finos fabricados por evaporacao termica a vacuo

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Jose Diego

    2015-07-01

    The supramolecular arrangement of organic thin films is a factor that influences both optical and electrical properties of these films and, consequently, the technological applications involving organic electronics. In this dissertation, thin films of a perylene derivative (bis butylimido perylene, acronym BuPTCD) were produced by physical vapor deposition (PVD) using vacuum thermal evaporation. The aim of this work was to investigate the supramolecular arrangement of BuPTCD films, which implies to control the thickness at nanometer scale and to determine the molecular organization, the morphology (at nano and micrometer scales) and the crystallinity, besides the stability of this arrangement as a function of the temperature. Optical properties (such as absorption and emission) and electrical properties (such as conductivity and photoconductivity) were also determined. The UV-Vis absorption spectra revealed a controlled growth (uniform) of the BuPTCD films. Atomic force and optical microscopy images showed a homogeneous surface of the film at nano and micrometer scales, respectively. The X-ray diffraction showed that the BuPTCD powder and PVD film have different crystalline structures, with the BuPTCD molecules head-on oriented in the PVD films, supported on the substrate surface by the side group (FTIR). This structure favors the light emission (photoluminescence) by the formation of excimers. The thermal treatment (200°C for 10 min) does not affect the molecular organization of the PVD films, showing a thermal stability of the BuPTCD supramolecular arrangement under these circumstances. The electrical measurements (DC) showed a linear increase of the current as a function of the tension, which is characteristic of ohmic behavior. Also, the films exhibited an increase of current by 2 orders of magnitude when exposed to light (photoconductive properties). Finally, BuPTCD films were exposed to vapor of trifluoroacetic acid (TFA) to verify the sensitivity of the Bu

  13. Magnesium growth in magnesium deuteride thin films during deuterium desorption

    Energy Technology Data Exchange (ETDEWEB)

    Checchetto, R., E-mail: riccardo.checchetto@unitn.it [Dipartimento di Fisica and CNISM, Università di Trento, Via Sommarive 14, I-38123 Trento (Italy); Miotello, A. [Dipartimento di Fisica and CNISM, Università di Trento, Via Sommarive 14, I-38123 Trento (Italy); Mengucci, P.; Barucca, G. [Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Università Politecnica delle Marche, I-60131 Ancona (Italy)

    2013-12-15

    Highlights: ► Highly oriented Pd-capped magnesium deuteride thin films. ► The MgD{sub 2} dissociation was studied at temperatures not exceeding 100 °C. ► The structure of the film samples was analyzed by XRD and TEM. ► The transformation is controlled by the re-growth velocity of the Mg layers. ► The transformation is thermally activated, activation energy value of 1.3 ± 0.1 eV. -- Abstract: Pd- capped nanocrystalline magnesium thin films having columnar structure were deposited on Si substrate by e-gun deposition and submitted to thermal annealing in D{sub 2} atmosphere to promote the metal to deuteride phase transformation. The kinetics of the reverse deuteride to metal transformation was studied by Thermal Desorption Spectroscopy (TDS) while the structure of the as deposited and transformed samples was analyzed by X-rays diffraction and Transmission Electron Microscopy (TEM). In Pd- capped MgD{sub 2} thin films the deuteride to metal transformation begins at the interface between un-reacted Mg and transformed MgD{sub 2} layers. The D{sub 2} desorption kinetics is controlled by MgD{sub 2}/Mg interface effects, specifically the re-growth velocity of the Mg layers. The Mg re-growth has thermally activated character and shows an activation energy value of 1.3 ± 0.1 eV.

  14. Thin film bioreactors in space

    Science.gov (United States)

    Hughes-Fulford, M.; Scheld, H. W.

    Studies from the Skylab, SL-3 and D-1 missions have demonstrated that biological organisms grown in microgravity have changes in basic cellular functions such as DNA, mRNA and protein synthesis, cytoskeleton synthesis, glucose utilization and cellular differentiation. Since microgravity could affect prokaryotic and eukaryotic cells at a subcellular and molecular level, space offers us an opportunity to learn more about basic biological systems with one important variable removed. The thin film bioreactor will facilitate the handling of fluids in microgravity, under constant temperature and will allow multiple samples of cells to be grown with variable conditions. Studies on cell cultures grown in microgravity would enable us to identify and quantify changes in basic biological function in microgravity which are needed to develop new applications of orbital research and future biotechnology.

  15. Progress in thin film techniques

    International Nuclear Information System (INIS)

    Weingarten, W.

    1996-01-01

    Progress since the last Workshop is reported on superconducting accelerating RF cavities coated with thin films. The materials investigated are Nb, Nb 3 Sn, NbN and NbTiN, the techniques applied are diffusion from the vapour phase (Nb 3 Sn, NbN), the bronze process (Nb 3 Sn), and sputter deposition on a copper substrate (Nb, NbTiN). Specially designed cavities for sample evaluation by RF methods have been developed (triaxial cavity). New experimental techniques to assess the RF amplitude dependence of the surface resistance are presented (with emphasis on niobium films sputter deposited on copper). Evidence is increasing that they are caused by magnetic flux penetration into the surface layer. (R.P.)

  16. BDS thin film damage competition

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-10-24

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

  17. Polycrystalline thin films : A review

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-09-01

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

  18. Formation and photopatterning of nanoporous titania thin films

    International Nuclear Information System (INIS)

    Park, Oun-Ho; Cheng, Joy Y.; Kim, Hyun Suk; Rice, Philip M.; Topuria, Teya; Miller, Robert D.; Kim, Ho-Cheol

    2007-01-01

    Photopatternable nanoporous titania thin films were generated from mixtures of an organic diblock copolymer, poly(styrene-b-ethylene oxide) (PS-b-PEO), and an oligomeric titanate (OT) prepared from a chelated titanium isopropoxide. The PS-b-PEO templates well-defined microdomains in thin films of the mixtures, which upon thermal treatment at 450 deg. C, become nanopores in titania. Average pore size and porosity are controlled by the molecular weight and loading level of the PS-b-PEO, respectively. Patterns of nanoporous titania were created by selectively exposing UV light on the mixture films. The UV irradiation destroys the chelating bond and induces the cross-linking reaction of the OT. Subsequent wet development followed by thermal treatment gives patterned nanoporous films of anatase phase titania

  19. Effect of cadmium incorporation on the properties of zinc oxide thin films

    Science.gov (United States)

    Bharath, S. P.; Bangera, Kasturi V.; Shivakumar, G. K.

    2018-02-01

    Cd x Zn1-x O (0 ≤ x ≤ 0.20) thin films are deposited on soda lime glass substrates using spray pyrolysis technique. To check the thermal stability, Cd x Zn1-x O thin films are subjected to annealing. Both the as-deposited and annealed Cd x Zn1-x O thin films are characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDAX) to check the structural, surface morphological and compositional properties, respectively. XRD analysis reveals that the both as-deposited and annealed Cd x Zn1-x O thin films are (002) oriented with wurtzite structure. SEM studies confirm that as-deposited, as well as annealed Cd x Zn1-x O thin films are free from pinholes and cracks. Compositional analysis shows the deficiency in Cd content after annealing. Optical properties evaluated from UV-Vis spectroscopy shows red shift in the band gap for Cd x Zn1-x O thin films. Electrical property measured using two probe method shows a decrease in the resistance after Cd incorporation. The results indicate that cadmium can be successfully incorporated in zinc oxide thin films to achieve structural changes in the properties of films.

  20. Adhesion of Antireflective Coatings in Multijunction Photovoltaics: Preprint

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-06-16

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

  1. Stabilized thin film heterostructure for electrochemical applications

    DEFF Research Database (Denmark)

    2015-01-01

    The invention provides a method for the formation of a thin film multi-layered heterostructure upon a substrate, said method comprising the steps of: a. providing a substrate; b. depositing a buffer layer upon said substrate, said buffer layer being a layer of stable ionic conductor (B); c...... or less; and e. repeating steps b. and c. a total of N times, such that N repeating pairs of layers (A/B) are built up, wherein N is 1 or more. The invention also provides a thin film multi-layered heterostructure as such, and the combination of a thin film multi-layered heterostructure and a substrate...

  2. Macro stress mapping on thin film buckling

    International Nuclear Information System (INIS)

    Goudeau, P.; Villain, P.; Renault, P.-O.; Tamura, N.; Celestre, R.S.; Padmore, H.A.

    2002-01-01

    Thin films deposited by Physical Vapour Deposition techniques on substrates generally exhibit large residual stresses which may be responsible of thin film buckling in the case of compressive stresses. Since the 80's, a lot of theoretical work has been done to develop mechanical models but only a few experimental work has been done on this subject to support these theoretical approaches and nothing concerning local stress measurement mainly because of the small dimension of the buckling (few 10th mm). This paper deals with the application of micro beam X-ray diffraction available on synchrotron radiation sources for stress mapping analysis of gold thin film buckling

  3. Study of zinc oxide thin film characteristics

    OpenAIRE

    Johari Shazlina; Muhammad Nazalea Yazmin; Zakaria Mohd Rosydi

    2017-01-01

    This paper presents the characterization of ZnO thin films with the thickness of 8nm, 30nm, and 200nm. The thin films were prepared using sol-gel method and has been deposited onto different substrate of silicon wafer, glass and quartz. The thin films were annealed at 400, 500 and 600°C. By using UV-Vis, the optical transmittance measurement were recorded by using a single beam spectrophotometer in the wavelength 250nm to 800nm. However, the transmittance in the visible range is hardly influe...

  4. Nanostructured thin films and coatings functional properties

    CERN Document Server

    Zhang, Sam

    2010-01-01

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

  5. Structures and Elastic Moduli of Polymer Nanocomposite Thin Films

    Science.gov (United States)

    Yuan, Hongyi; Karim, Alamgir; University of Akron Team

    2014-03-01

    Polymeric thin films generally possess unique mechanical and thermal properties due to confinement. In this study we investigated structures and elastic moduli of polymer nanocomposite thin films, which can potentially find wide applications in diverse areas such as in coating, permeation and separation. Conventional thermoplastics (PS, PMMA) and biopolymers (PLA, PCL) were chosen as polymer matrices. Various types of nanoparticles were used including nanoclay, fullerene and functionalized inorganic particles. Samples were prepared by solvent-mixing followed by spin-coating or flow-coating. Film structures were characterized using X-ray scattering and transmission electron microscopy. Elastic moduli were measured by strain-induced elastic buckling instability for mechanical measurements (SIEBIMM), and a strengthening effect was found in certain systems due to strong interaction between polymers and nanoparticles. The effects of polymer structure, nanoparticle addition and film thickness on elastic modulus will be discussed and compared with bulk materials.

  6. Temperature range for critical scaling behavior in YBCO thin films

    Science.gov (United States)

    Deak, J.; Darwin, M. J.; McElfresh, M.

    1993-11-01

    The magnetic and transport properties of thin films and single crystals of YBa 2Cu 3O 7-δ are compared. For measurements on thin films, the apparent critical scaling behavior is observed to exist over a temperature range from 87 K down to the vortex-glass transition Tg = 84.2 K at 2.5 kOE and from 83 K to Tg = 70.4 K at 50 kOe. The inflection point ( Tinf) in temperature dependent resistivity measurements R( T) coincides with the highest temperature at which current-voltage ( I-V) characteristics are found to scale. The region between Tg and Tinf shows a behavior characteristics of thermally activated flux motion, while above TinfI-V curves show ohmic behavior. No similar scaling region is observed in some single crystal results, supporting recent claims that the phase transition in some single crystals may not be critical in nature (of order greater than one).

  7. Rapid thermally annealed plasma deposited SiNx:H thin films: Application to metal-insulator-semiconductor structures with Si, In0.53Ga0.47As, and InP

    International Nuclear Information System (INIS)

    Martil, I.; Prado, A. del; San Andres, E.; Gonzalez Diaz, G.; Martinez, F.L.

    2003-01-01

    We present in this article a comprehensive study of rapid thermal annealing (RTA) effects on the physical properties of SiN x :H thin films deposited by the electron cyclotron resonance plasma method. Films of different as-deposited compositions (defined in this article as the nitrogen to silicon ratio, x=N/Si) were analyzed: from Si-rich (x=0.97) to N-rich (x=1.6) films. The evolution of the composition, bonding configuration, and paramagnetic defects with the annealing temperature are explained by means of different network bond reactions that take place depending on the as-deposited film composition. All the analyzed films release hydrogen, while Si-rich and near-stoichiometric (x=1.43) ones also lose nitrogen upon annealing. These films were used to make Al/SiN x :H/semiconductor devices with Si, In 0.53 Ga 0.47 As, and InP. After RTA treatments, the electrical properties of the three different SiN x :H/semiconductor interfaces can be explained, noting the microstructural modifications that SiN x :H experiences upon annealing

  8. Thin film production method and apparatus

    Science.gov (United States)

    Loutfy, Raouf O.; Moravsky, Alexander P.; Hassen, Charles N.

    2010-08-10

    A method for forming a thin film material which comprises depositing solid particles from a flowing suspension or aerosol onto a filter and next adhering the solid particles to a second substrate using an adhesive.

  9. Highly stretchable wrinkled gold thin film wires.

    Science.gov (United States)

    Kim, Joshua; Park, Sun-Jun; Nguyen, Thao; Chu, Michael; Pegan, Jonathan D; Khine, Michelle

    2016-02-08

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

  10. Physical properties and characterization of Ag doped CdS thin films

    International Nuclear Information System (INIS)

    Shah, N.A.; Nazir, A.; Mahmood, W.; Syed, W.A.A.; Butt, S.; Ali, Z.; Maqsood, A.

    2012-01-01

    Highlights: ► CdS thin films were grown. ► By ion exchange, Ag was doped. ► Physical properties were investigated. - Abstract: Thin films of cadmium sulfide with very well defined preferential orientation and relatively high absorption coefficient were fabricated by thermal evaporation technique. The research is focused to the fabrication and characterization of the compositional data of CdS thin films obtained by using X-ray diffraction, scanning electron microscope along with energy dispersive X-ray spectroscopy. The optical properties were studied by using a UV-VIS-NIR spectrophotometer. The effects of silver-doping by ion exchange process on the properties of as-deposited CdS thin films have been investigated.

  11. Surface, interface and thin film characterization of nano-materials using synchrotron radiation

    International Nuclear Information System (INIS)

    Kimura, Shigeru; Kobayashi, Keisuke

    2005-01-01

    From the results of studies in the nanotechnology support project of the Ministry of Education, Culture, Sports, Science and Technology of Japan, several investigations on the surface, interface and thin film characterization of nano-materials are described; (1) the MgB 2 thin film by X-ray diffraction, (2) the magnetism of the Pt thin film on a Co film by X-ray magnetic circular dichroism measurement, (3) the structure and physical properties of oxygen molecules absorbed in a micro hole of the cheleted polymer crystal by the direct observation in X-ray powder diffraction, and (4) the thin film gate insulator with a large dielectric constant, thermally treated HfO 2 /SiO 2 /Si, by X-ray photoelectron spectroscopy. (M.H.)

  12. Epitaxy, thin films and superlattices

    International Nuclear Information System (INIS)

    Jagd Christensen, Morten

    1997-05-01

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

  13. Epitaxy, thin films and superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Jagd Christensen, Morten

    1997-05-01

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

  14. Micromechanics of substrate-supported thin films

    Science.gov (United States)

    He, Wei; Han, Meidong; Wang, Shibin; Li, Lin-An; Xue, Xiuli

    2017-09-01

    The mechanical properties of metallic thin films deposited on a substrate play a crucial role in the performance of micro/nano-electromechanical systems (MEMS/NEMS) and flexible electronics. This article reviews ongoing study on the mechanics of substrate-supported thin films, with emphasis on the experimental characterization techniques, such as the rule of mixture and X-ray tensile testing. In particular, the determination of interfacial adhesion energy, film deformation, elastic properties and Bauschinger effect are discussed.

  15. Thin films of copper antimony sulfide: A photovoltaic absorber material

    Energy Technology Data Exchange (ETDEWEB)

    Ornelas-Acosta, R.E. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Shaji, S. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Universidad Autónoma de Nuevo León-CIIDIT, Apodaca, Nuevo León (Mexico); Avellaneda, D.; Castillo, G.A.; Das Roy, T.K. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Krishnan, B., E-mail: kbindu_k@yahoo.com [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Universidad Autónoma de Nuevo León-CIIDIT, Apodaca, Nuevo León (Mexico)

    2015-01-15

    Highlights: • CuSbS{sub 2} thin films were prepared by heating Sb{sub 2}S{sub 3}/Cu layers. • Analyzed the structure, composition, optical, and electrical properties. • PV structures: glass/SnO{sub 2}:F/n-CdS/p-CuSbS{sub 2}/C/Ag were formed at different conditions. • The PV parameters (J{sub sc}, V{sub oc}, and FF) were evaluated from the J–V characteristics. • J{sub sc}: 0.52–3.20 mA/cm{sup 2}, V{sub oc}:187–323 mV, FF: 0.27–0.48 were obtained. - Abstract: In this work, we report preparation and characterization of CuSbS{sub 2} thin films by heating glass/Sb{sub 2}S{sub 3}/Cu layers and their use as absorber material in photovoltaic structures: glass/SnO{sub 2}:F/n-CdS/p-CuSbS{sub 2}/C/Ag. The Sb{sub 2}S{sub 3} thin films of 600 nm were prepared by chemical bath deposition on which copper thin films of 50 nm were thermally evaporated, and the glass/Sb{sub 2}S{sub 3}/Cu multilayers were heated in vacuum at different temperatures. X-ray diffraction analysis showed the formation of orthorhombic CuSbS{sub 2} after heating the precursor layers. Studies on identification and chemical state of the elements were done using X-ray photoelectron spectroscopy. The optical band gap of the CuSbS{sub 2} thin films was 1.55 eV and the thin films were photoconductive. The photovoltaic parameters of the devices using CuSbS{sub 2} as absorber and CdS as window layer were evaluated from the J–V curves, yielding J{sub sc}, V{sub oc}, and FF values in the range of 0.52–3.20 mA/cm{sup 2}, 187–323 mV, and 0.27–0.48, respectively, under illumination of AM1.5 radiation.

  16. The microstructures and electrical properties of Y-doped amorphous vanadium oxide thin films

    Science.gov (United States)

    Gu, Deen; Zhou, Xin; Guo, Rui; Wang, Zhihui; Jiang, Yadong

    2017-03-01

    One of promising approaches for further improving the sensitivity of microbolometer arrays with greatly-reduced pixel size is using the thermal-sensitive materials with higher performance. In this paper, Y-doped vanadium oxide (VOx) thin films prepared by a reactively sputtering process exhibit enhanced performance for the microbolometer application compared with frequently-applied VOx thin films. Both undoped and Y-doped VOx thin films are amorphous due to the relatively low deposition temperature. Y-doped VOx thin films exhibit smoother surface morphology than VOx due to the restrained expansion of particles during depositions. Y-doping increases the temperature coefficient of resistivity by over 20% for the doping level of 1.30 at%. The change rate of resistivity, after aging for 72 h, of thin films was reduced from about 15% for undoped VOx to 2% due to the introduction of Y. Moreover, Y-doped VOx thin films have a low 1/f noise level as VOx ones. Y-doping provides an attractive approach for preparing VOx thermal-sensitive materials with enhanced performance for microbolometers.

  17. Synthesis and characterization of copper antimony tin sulphide thin films for solar cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Ali, N., E-mail: nisar.ali@utm.my [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor (Malaysia); Department of Physics, Govt. Post Graduate Jehanzeb College Saidu Sharif, Swat, 19200 (Pakistan); Hussain, A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor (Malaysia); Ahmed, R., E-mail: rashidahmed@utm.my [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor (Malaysia); Wan Shamsuri, W.N. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, UTM Skudai, 81310 Johor (Malaysia); Fu, Y.Q., E-mail: richard.fu@northumbria.ac.uk [Department of Physics and Electrical Engineering, Faculty of Engineering & Environment, University of Northumbria, Newcastle upon Tyne, NE1 8ST (United Kingdom)

    2016-12-30

    Highlights: • A new and novel material for solar cell applications is demonstrated as a replacement for toxic and expansive compounds. • The materials used in this compound are abundant and low cost. • Compound exhibit unusual optical and electrical properties. • The band gap was found to be comparable with that of GaAs. - Abstract: Low price thin film modules based on Copper antimony tin sulphide (CATS) are introduced for solar harvesting to compete for the already developed compound semiconductors. Here, CATS thin films were deposited on soda lime glass by thermal evaporation technique followed by a rapid thermal annealing in an argon atmosphere. From Our XRD analysis, it was revealed that the annealed samples were poly-crystalline and their crystallinity was improved with increasing annealing temperature. The constituent elements and their corresponding chemical states were identified using X-ray photoelectron spectroscopy. The obtained optical band gap of 1.4 eV for CATS thin film is found nearly equal to GaAs – one of the highly efficient thin film material for solar cell technology. Furthermore, our observed good optical absorbance and low transmittance for the annealed CATS thin films in the visible region of light spectrum assured the aptness of the CATS thin films for solar cell applications.

  18. Synthesis and characterization of Cu–Al–Ni shape memory alloy multilayer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Cortés, J.F. [Dpt. Física Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); San Juan, J., E-mail: jose.sanjuan@ehu.es [Dpt. Física Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); López, G.A.; Nó, M.L. [Dpt. Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain)

    2013-10-01

    Among active materials, shape memory alloys are well recognized for their work output density. Because of that, these alloys have attracted much attention to be used in micro/nano electromechanical systems. In the present work, the electron beam evaporation technique has been used to growth, by a multilayer method, two shape memory alloy thin films with different Cu–Al–Ni composition. Multilayers have been further thermally treated to produce the alloys by solid solution diffusion. The produced multilayers have been characterized and the presence of the martensite phase in the obtained thin films was studied. Furthermore, the influence of two different coatings onto the Si substrates, namely Si/SiO{sub 2} and Si/Si{sub 3}N{sub 4}, was investigated. Mechanically stable, not detaching from the substrates, Cu–Al–Ni shape memory alloy thin films, about 1 micrometre thick, showing a martensitic transformation have been produced. - Highlights: ► Multilayer thin films of Cu–Al–Ni shape memory alloys produced by e-beam evaporation. ► SiN{sub X} 200 nm thick coating is good for high quality Cu–Al–Ni shape memory thin films. ► Thermal treatment renders Cu–Al–Ni multilayer in homogeneous martensite thin film.

  19. Laser processing for thin-film photovoltaics

    Science.gov (United States)

    Compaan, Alvin D.

    1995-04-01

    Over the past decade major advances have occurred in the field of thin- film photovoltaics (PV) with many of them a direct consequence of the application of laser processing. Improved cell efficiencies have been achieved in crystalline and polycrystalline Si, in hydrogenated amorphous silicon, and in two polycrystalline thin-film materials. The use of lasers in photovoltaics includes laser hole drilling for emitter wrap-through, laser trenching for buried bus lines, and laser texturing of crystalline and polycrystalline Si cells. In thin-film devices, laser scribing is gaining increased importance for module interconnects. Pulsed laser recrystallization of boron-doped hydrogenated amorphous silicon is used to form highly conductive p-layers in p-i-n amorphous silicon cells and in thin-film transistors. Optical beam melting appears to be an attractive method for forming metal semiconductor alloys for contact formation. Finally, pulsed lasers are used for deposition of the entire semiconductor absorber layer in two types of polycrystalline thin-film cells-those based on copper indium diselenide and those based on cadmium telluride. In our lab we have prepared and studied heavily doped polycrystalline silicon thin films and also have used laser physical vapor deposition (LPVD) to prepare 'all-LPVD' CdS/CdTe solar cells on glass with efficiencies tested at NREL at 10.5%. LPVD is highly flexible and ideally suited for prototyping PV cells using ternary or quaternary alloys and for exploring new dopant combinations.

  20. Laser applications in thin-film photovoltaics

    Science.gov (United States)

    Bartlome, R.; Strahm, B.; Sinquin, Y.; Feltrin, A.; Ballif, C.

    2010-08-01

    We review laser applications in thin-film photovoltaics (thin-film Si, CdTe, and Cu(In,Ga)Se2 solar cells). Lasers are applied in this growing field to manufacture modules, to monitor Si deposition processes, and to characterize opto-electrical properties of thin films. Unlike traditional panels based on crystalline silicon wafers, the individual cells of a thin-film photovoltaic module can be serially interconnected by laser scribing during fabrication. Laser scribing applications are described in detail, while other laser-based fabrication processes, such as laser-induced crystallization and pulsed laser deposition, are briefly reviewed. Lasers are also integrated into various diagnostic tools to analyze the composition of chemical vapors during deposition of Si thin films. Silane (SiH4), silane radicals (SiH3, SiH2, SiH, Si), and Si nanoparticles have all been monitored inside chemical vapor deposition systems. Finally, we review various thin-film characterization methods, in which lasers are implemented.

  1. Structural, Optical and Electrical Properties of ITO Thin Films

    Science.gov (United States)

    Sofi, A. H.; Shah, M. A.; Asokan, K.

    2018-02-01

    Transparent and conductive thin films of indium tin oxide were fabricated on glass substrates by the thermal evaporation technique. Tin doped indium ingots with low tin content were evaporated in vacuum (1.33 × 10-7 kpa) followed by an oxidation for 15 min in the atmosphere in the temperature range of 600-700°C. The structure and phase purity, surface morphology, optical and electrical properties of thin films were studied by x-ray diffractometry and Raman spectroscopy, scanning electron microcopy and atomic force microscopy, UV-visible spectrometry and Hall measurements in the van der Pauw configuration. The x-ray diffraction study showed the formation of the cubical phase of polycrystalline thin films. The morphological analysis showed the formation of ginger like structures and the energy dispersive x-ray spectrum confirmed the presence of indium (In), tin (Sn) and oxygen (O) elements. Hall measurements confirmed n-type conductivity of films with low electrical resistivity ( ρ) ˜ 10-3 Ω cm and high carrier concentration ( n) ˜ 1020 cm-3. For prevalent scattering mechanisms in the films, experimental data was analyzed by calculating a mean free path ( L) using a highly degenerate electron gas model. Furthermore, to investigate the performance of the deposited films as a transparent conductive material, the optical figure of merit was obtained for all the samples.

  2. Deposition techniques for the preparation of thin film nuclear targets

    International Nuclear Information System (INIS)

    Muggleton, A.H.F.

    1987-07-01

    This review commences with a brief description of the basic principles that regulate vacuum evaporation and the physical processes involved in thin film formation, followed by a description of the experimental methods used. The principle methods of heating the evaporant are detailed and the means of measuring and controlling the film thickness are elucidated. Types of thin film nuclear targets are considered and various film release agents are listed. Thin film nuclear target behaviour under ion-bombardment is described and the dependence of nuclear experimental results upon target thickness and uniformity is outlined. Special problems associated with preparing suitable targets for lifetime measurements are discussed. The causes of stripper-foil thickening and breaking under heavy-ion bombardment are considered. A comparison is made between foils manufactured by a glow discharge process and those produced by vacuum sublimation. Consideration is given to the methods of carbon stripper-foil manufacture and to the characteristics of stripper-foil lifetimes are considered. Techniques are described that have been developed for the fabrication of special targets, both from natural and isotopically enriched material, and also of elements that are either chemically unstable, or thermally unstable under irradiation. The reduction of metal oxides by the use of hydrogen or by utilising a metallothermic technique, and the simultaneous evaporation of reduced rare earth elements is described. A comprehensive list of the common targets is presented

  3. Experimental study of Evanohm thin film resistors at subkelvin temperatures

    International Nuclear Information System (INIS)

    Satrapinski, A F; Hahtela, O; Savin, A M; Novikov, S

    2008-01-01

    Thin film resistors, based on the Evanohm (Ni 75% Cr 20% Cu 2.5% Al 2.5% ) alloy, have been investigated at cryogenic temperatures. The objective of the study is the development of the high value resistor for precision electrical measurements at low temperature and particularly for metrological triangle experiments. Thin film resistors of different configurations have been designed and fabricated by the thermal evaporation process. The resistivity of investigated resistors is 110 × 10 −8 Ω m; the resistance exhibits a Kondo minimum at a temperature near 30 K and increases with further reduction of temperature. In the temperature range 50–65 mK, the temperature coefficient reaches −20 × 10 −3 K −1 . Power dependence measurements at subkelvin temperatures demonstrate that noticeable electron overheating takes place only at the power level above 10 pW for a 500 kΩ resistor. The electron–phonon coupling constant for the fabricated Evanohm thin films has been derived from experimental results

  4. Structural and optical properties of electrodeposited molybdenum oxide thin films

    International Nuclear Information System (INIS)

    Patil, R.S.; Uplane, M.D.; Patil, P.S.

    2006-01-01

    Electrosynthesis of Mo(IV) oxide thin films on F-doped SnO 2 conducting glass (10-20/Ω/□) substrates were carried from aqueous alkaline solution of ammonium molybdate at room temperature. The physical characterization of as-deposited films carried by thermogravimetric/differential thermogravimetric analysis (TGA/DTA), infrared spectroscopy and X-ray diffraction (XRD) showed the formation of hydrous and amorphous MoO 2 . Scanning electron microscopy (SEM) revealed a smooth but cracked surface with multi-layered growth. Annealing of these films in dry argon at 450 deg. C for 1 h resulted into polycrystalline MoO 2 with crystallites aligned perpendicular to the substrate. Optical absorption study indicated a direct band gap of 2.83 eV. The band gap variation consistent with Moss rule and band gap narrowing upon crystallization was observed. Structure tailoring of as-deposited thin films by thermal oxidation in ambient air to obtain electrochromic Mo(VI) oxide thin films was exploited for the first time by this novel route. The results of this study will be reported elsewhere

  5. Thermal stability of alumina thin films containing γ-Al.sub.2./sub.O.sub.3./sub. phase prepared by reactive magnetron sputtering

    Czech Academy of Sciences Publication Activity Database

    Musil, Jindřich; Blažek, J.; Zeman, P.; Prokšová, Š.; Šašek, M.; Čerstvý, R.

    2010-01-01

    Roč. 257, č. 3 (2010), s. 1058-1062 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z10100520 Keywords : Al 2 O 3 (alumina) * annealing * thermal stability * nanocrystalline material * sputtering Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.795, year: 2010

  6. Optically Immersed Bolometer IR Detectors Based on V2O5 Thin Films with Polyimide Thermal Impedance Control Layer for Space Applications

    Science.gov (United States)

    Sumesh, M. A.; Thomas, Beno; Vijesh, T. V.; Mohan Rao, G.; Viswanathan, M.; Karanth, S. P.

    2018-01-01

    Optically immersed bolometer IR detectors were fabricated using electron beam evaporated vanadium oxide as the sensing material. Spin-coated polyimide was used as medium to optically immerse the sensing element to the flat surface of a hemispherical germanium lens. This optical immersion layer also serves as the thermal impedance control layer and decides the performance of the devices in terms of responsivity and noise parameters. The devices were packaged in suitable electro-optical packages and the detector parameters were studied in detail. Thermal time constant varies from 0.57 to 6.0 ms and responsivity from 75 to 757 V W-1 corresponding to polyimide thickness in the range 2 to 70 μm for a detector bias of 9 V in the wavelength region of 14-16 μm. Highest D* obtained was 1.2×108 cmHz1/2 W-1. Noise equivalent temperature difference (NETD) of 20 mK was achieved for devices with polyimide thickness more than 32 μm. The figure of merit, NETD × τ product which describes trade-off between thermal time constant and sensitivity is also extensively studied for devices having different thickness of thermal impedance layers.

  7. Thermal-induced changes on the properties of spin-coated P3HT:C60 thin films for solar cell applications

    CSIR Research Space (South Africa)

    Motaung, DE

    2009-09-01

    Full Text Available The thermal transition behaviour, optical and structural properties of spin-coated P3HT:C60 blended films with different C60 ratios were investigated using differential scanning calorimetry (DSC), thermo-gravimetric analysis (TGA), ultraviolet...

  8. Reversible Surface Properties of Polybenzoxazine/Silica Nanocomposites Thin Films

    Directory of Open Access Journals (Sweden)

    Wei-Chen Su

    2013-01-01

    Full Text Available We report the reversible surface properties (hydrophilicity, hydrophobicity of a polybenzoxazine (PBZ thin film through simple application of alternating UV illumination and thermal treatment. The fraction of intermolecularly hydrogen bonded O–H⋯O=C units in the PBZ film increased after UV exposure, inducing a hydrophilic surface; the surface recovered its hydrophobicity after heating, due to greater O–H⋯N intramolecular hydrogen bonding. Taking advantage of these phenomena, we prepared a PBZ/silica nanocomposite coating through two simple steps; this material exhibited reversible transitions from superhydrophobicity to superhydrophilicity upon sequential UV irradiation and thermal treatment.

  9. Properties of MoO3 thin film polymorphs

    International Nuclear Information System (INIS)

    McCarron, E.M.; Carcia, P.F.

    1987-01-01

    Thin film polymorphs of molybdenum trioxide have been synthesized by RF sputtering. Films deposited on thermally floating substrates are polycrystalline and exhibit preferred orientation. Depending upon the oxygen partial pressure maintained during sputtering, the films can be made to crystallize in either the thermodynamically stable orthorhombic α MoO 3 form (unique 2D-layered structure) or the metastable monoclinic β MoO 3 phase (3D ReO 3 -related structure). Metastable β films can be converted thermally to the α phase and the transformation appears topotactic. Films deposited on the cooled substrates are amorphous. A correlation between the particular phase formed and adatom mobility is noted

  10. Defect study on infrared thin film of 3.8um

    Science.gov (United States)

    Zhang, Yao-ping; Xu, Hong; Ling, Ning; Zhang, Yun-dong

    2006-02-01

    Defects in thin film are the most important factors resulting in laser-induced damage of far-infrared laser thin film components, and always a major concern. The defect is a primary problem for infrared thin film of 3.8um in some optical systems. In this paper, single layer of ZnS YbF3 and multilayer coating is produced by thermal evaporation, and species, properties and derivation of defects in these thin films are introduced firstly, Then, the influence of material and evaporation rate on the surface defect density of laser thin film is analyzed. Finally, this paper put forward the appropriate deposition rates of thin film. The result shows that the nodule and concave hole defects are the mainly in the infrared thin film of 3.8um, and YbF3 has a great effect on the defect density in thin film. Also, the deposition rate of YbF3 has a large effect on the number and area of particles deposited on the substrate, as the evaporation rate increases, the number of particles increases markedly. It is possible that the spitting change of fused deposition material increases when the rate increases, since the centre temperature of fused deposition material increases. The defect density from 7.3X10 -3 reduces to 6.8X10 -4 through reducing the rate. Finally, the authors found it was appropriate when deposition rates were 4Å/s for ZnS and 2Å/s for YbF3, respectively.

  11. Swift heavy ion induced modifications in optical and electrical properties of cadmium selenide thin films

    Science.gov (United States)

    Choudhary, Ritika; Chauhan, Rishi Pal

    2017-07-01

    The modification in various properties of thin films using high energetic ion beam is an exciting area of basic and applied research in semiconductors. In the present investigations, cadmium selenide (CdSe) thin films were deposited on ITO substrate using electrodeposition technique. To study the swift heavy ion (SHI) induced effects, the deposited thin films were irradiated with 120 MeV heavy Ag9+ ions using pelletron accelerator facility at IUAC, New Delhi, India. Structural phase transformation in CdSe thin film from metastable cubic phase to stable hexagonal phase was observed after irradiation leading to decrease in the band gap from 2.47 eV to 2.12 eV. The phase transformation was analyzed through X-ray diffraction patterns. During SHI irradiation, Generation of high temperature and pressure by thermal spike along the trajectory of incident ions in the thin films might be responsible for modification in the properties of thin films.[Figure not available: see fulltext.

  12. Ion irradiation of AZO thin films for flexible electronics

    Energy Technology Data Exchange (ETDEWEB)

    Boscarino, Stefano; Torrisi, Giacomo; Crupi, Isodiana [IMM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania (Italy); Alberti, Alessandra [CNR-IMM, via Strada VIII 5, 95121 Catania (Italy); Mirabella, Salvatore; Ruffino, Francesco [IMM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania (Italy); Terrasi, Antonio, E-mail: antonio.terrasi@ct.infn.it [IMM-CNR and Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania (Italy)

    2017-02-01

    Highlights: • Evidence of electrical good quality AZO ultra thin films without thermal annealing. • Evidence of the main role of Oxygen vs. structural parameters in controlling the electrical performances of AZO. • Evidence of the role of the ion irradiation in improving the electrical properties of AZO ultra thin films. • Synthesis of AZO thin films on flexible/plastic substrates with good electrical properties without thermal processes. - Abstract: Aluminum doped Zinc oxide (AZO) is a promising transparent conductor for solar cells, displays and touch-screen technologies. The resistivity of AZO is typically improved by thermal annealing at temperatures not suitable for plastic substrates. Here we present a non-thermal route to improve the electrical and structural properties of AZO by irradiating the TCO films with O{sup +} or Ar{sup +} ion beams (30–350 keV, 3 × 10{sup 15}–3 × 10{sup 16} ions/cm{sup 2}) after the deposition on glass and flexible polyethylene naphthalate (PEN). X-ray diffraction, optical absorption, electrical measurements, Rutherford Backscattering Spectrometry and Atomic Force Microscopy evidenced an increase of the crystalline grain size and a complete relief of the lattice strain upon ion beam irradiation. Indeed, the resistivity of thin AZO films irradiated at room temperature decreased of two orders of magnitude, similarly to a thermal annealing at 400 °C. We also show that the improvement of the electrical properties does not simply depend on the strain or polycrystalline domain size, as often stated in the literature.

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

    Energy Technology Data Exchange (ETDEWEB)

    Headrick, Randall [Univ. of Vermont, Burlington, VT (United States)

    2016-03-18

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

  14. DC magnetron sputtering prepared Ag-C thin film anode for thin film lithium ion microbatteries

    International Nuclear Information System (INIS)

    Li, Y.; Tu, J.P.; Shi, D.Q.; Huang, X.H.; Wu, H.M.; Yuan, Y.F.; Zhao, X.B.

    2007-01-01

    An Ag-C thin film was prepared by DC magnetron co-sputtering, using pure silver and graphite as the targets. The microstructure and morphology of the deposited thin film were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Electrochemical performances of the Ag-C thin film anode were investigated by means of discharge/charge and cyclic voltammogram (CV) tests in model cells. The electrochemical impedance spectrum (EIS) characteristics and the chemical diffusion coefficient, D Li of the Ag-C thin film electrode at different discharging states were discussed. It was believed that the excellent cycling performance of the Ag-C electrode was ascribed to the good conductivity of silver and the volume stability of the thin film

  15. Thin Films in the Photovoltaic Industry

    International Nuclear Information System (INIS)

    Jaeger-Waldau, A.

    2008-03-01

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

  16. Physical and electrical properties of thermal oxidized Sm{sub 2}O{sub 3} gate oxide thin film on Si substrate: Influence of oxidation durations

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Kian Heng; Haseeb, A.S.M.A.; Wong, Yew Hoong, E-mail: yhwong@um.edu.my

    2016-05-01

    Growth of 150 nm Sm{sub 2}O{sub 3} films by sputtered pure samarium metal film on silicon substrates and followed by thermal oxidation process in oxygen ambient at 700 °C through various oxidation durations (5 min, 10 min, 15 min and 20 min) has been carried out. The crystallinity of Sm{sub 2}O{sub 3} film and existence of interfacial layer have been evaluated by X-ray diffraction, Fourier transform infrared and Raman analysis. Crystallite size and microstrain of Sm{sub 2}O{sub 3} were estimated by Williamson–Hall plot analysis. Calculated crystallite size of Sm{sub 2}O{sub 3} from Scherrer equation has similar trend with the value from Williamson–Hall plot. The presence of interfacial layer is supported by composition line scan by energy dispersive X-ray spectroscopy analysis. The surface roughness and surface topography of Sm{sub 2}O{sub 3} film were examined by atomic force microscopy analysis. The electrical characterization revealed that 15 min of oxidation durations with smoothest surface has highest breakdown voltage, lowest leakage current density and highest barrier height value. - Highlights: • Thermal oxidation of sputtered pure metallic Sm in oxygen ambient • Formation of polycrystalline Sm{sub 2}O{sub 3} and semi-polycrystalline interfacial layers • Optimization of oxidation duration of pure metallic Sm in oxygen ambient • Enhanced electrical performance with smooth surface and increased barrier height.

  17. Crystallization and electrical resistivity of Cu{sub 2}O and CuO obtained by thermal oxidation of Cu thin films on SiO{sub 2}/Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    De Los Santos Valladares, L., E-mail: ld301@cam.ac.uk [Cavendish Laboratory, University of Cambridge, J.J Thomson Av., Cambridge CB3 0HE (United Kingdom); Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan); Departamento de Fisica, Universidade Federal de Pernambuco, 50670-901, Recife-Pe (Brazil); Salinas, D. Hurtado [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan); Laboratorio de Ceramicos y Nanomateriales, Facultad de Ciencias Fisicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima (Peru); Dominguez, A. Bustamante [Laboratorio de Ceramicos y Nanomateriales, Facultad de Ciencias Fisicas, Universidad Nacional Mayor de San Marcos, Ap. Postal 14-0149, Lima (Peru); Najarro, D. Acosta [Instituto de Fisica, Departamento de Materia Condensada, Universidad Nacional Autonoma de Mexico, Ap. Postal 20-364, CP 01000 (Mexico); Khondaker, S.I. [NanoScience Technology Centre and Department of Physics, University of Central Florida, Orlando, FL 32826 (United States); Mitrelias, T.; Barnes, C.H.W. [Cavendish Laboratory, University of Cambridge, J.J Thomson Av., Cambridge CB3 0HE (United Kingdom); Aguiar, J. Albino [Departamento de Fisica, Universidade Federal de Pernambuco, 50670-901, Recife-Pe (Brazil); Majima, Y. [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan); CREST, Japan Science and Technology Agency (JST), 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan)

    2012-08-01

    In this work, we study the crystallization and electrical resistivity of the formed oxides in a Cu/SiO{sub 2}/Si thin film after thermal oxidation by ex-situ annealing at different temperatures up to 1000 Degree-Sign C. Upon increasing the annealing temperature, from the X ray diffractogram the phase evolution Cu {yields} Cu + Cu{sub 2}O {yields} Cu{sub 2}O {yields} Cu{sub 2}O + CuO {yields} CuO was detected. Pure Cu{sub 2}O films are obtained at 200 Degree-Sign C, whereas uniform CuO films without structural surface defects such as terraces, kinks, porosity or cracks are obtained in the temperature range 300-550 Degree-Sign C. In both oxides, crystallization improves with annealing temperature. A resistivity phase diagram, which is obtained from the current-voltage response, is presented here. The resistivity was expected to increase linearly as a function of the annealing temperature due to evolution of oxides. However, anomalous decreases are observed at different temperatures ranges, this may be related to the improvement of the crystallization and crystallite size when the temperature increases. - Highlights: Black-Right-Pointing-Pointer The crystallization and electrical resistivity of oxides in a Cu films are studied. Black-Right-Pointing-Pointer In annealing Cu films, the phase evolution Cu + Cu{sub 2}O {yields} Cu{sub 2}O {yields} Cu{sub 2}O + CuO {yields} CuO occurs. Black-Right-Pointing-Pointer A resistivity phase diagram, obtained from the current-voltage response, is presented. Black-Right-Pointing-Pointer Some decreases in the resistivity may be related to the crystallization.

  18. Enhanced thermal stability and mechanical properties of nitrogen deficient titanium aluminum nitride (Ti0.54Al0.46Ny) thin films by tuning the applied negative bias voltage

    Science.gov (United States)

    Calamba, K. M.; Schramm, I. C.; Johansson Jõesaar, M. P.; Ghanbaja, J.; Pierson, J. F.; Mücklich, F.; Odén, M.

    2017-08-01

    Aspects on the phase stability and mechanical properties of nitrogen deficient (Ti0.54Al0.46)Ny alloys were investigated. Solid solution alloys of (Ti,Al)N were grown by cathodic arc deposition. The kinetic energy of the impinging ions was altered by varying the substrate bias voltage from -30 V to -80 V. Films deposited with a high bias value of -80 V showed larger lattice parameter, finer columnar structure, and higher compressive residual stress resulting in higher hardness than films biased at -30 V when comparing their as-deposited states. At elevated temperatures, the presence of nitrogen vacancies and point defects (anti-sites and self-interstitials generated by the ion-bombardment during coating deposition) in (Ti0.54Al0.46)N0.87 influence the driving force for phase separation. Highly biased nitrogen deficient films have point defects with higher stability during annealing, which cause a delay of the release of the stored lattice strain energy and then accelerates the decomposition tendencies to thermodynamically stable c-TiN and w-AlN. Low biased nitrogen deficient films have retarded phase transformation to w-AlN, which results in the prolongment of age hardening effect up to 1100 °C, i.e., the highest reported temperature for Ti-Al-N material system. Our study points out the role of vacancies and point defects in engineering thin films with enhanced thermal stability and mechanical properties for high temperature hard coating applications.

  19. High performance weak donor-acceptor polymers in thin film transistors: effect of the acceptor on electronic properties, ambipolar conductivity, mobility, and thermal stability.

    Science.gov (United States)

    Yuen, Jonathan D; Fan, Jian; Seifter, Jason; Lim, Bogyu; Hufschmid, Ryan; Heeger, Alan J; Wudl, Fred

    2011-12-28

    We have studied the electronic, physical, and transistor properties of a family of donor-acceptor polymers consisting of diketopyrrolopyrrole (DPP) coupled with different accepting companion units in order to determine the effects of donor-acceptor interaction. Using the electronically neutral benzene (B), the weakly accepting benzothiadiazole (BT), and the strongly accepting benzobisthiadiazole (BBT), the accepting strength of the companion unit was systematically modulated. All polymers exhibited excellent transistor performance, with mobilities above 0.1 cm(2)V(-1)s(-1), even exceeding 1 cm(2)V(-1)s(-1) for one of the BBT-containing polymers. We find that the BBT is the strongest acceptor, enabling the BBT-containing polymers to be strongly ambipolar. The BBT moiety also strengthens interchain interactions, which provides higher thermal stability and performance for transistors with BBT-containing polymers as the active layer. © 2011 American Chemical Society

  20. Organic thin films and surfaces directions for the nineties

    CERN Document Server

    Ulman, Abraham

    1995-01-01

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

  1. Restructuring in block copolymer thin films

    DEFF Research Database (Denmark)

    Posselt, Dorthe; Zhang, Jianqi; Smilgies, Detlef-M.

    2017-01-01

    Block copolymer (BCP) thin films have been proposed for a number of nanotechnology applications, such as nanolithography and as nanotemplates, nanoporous membranes and sensors. Solvent vapor annealing (SVA) has emerged as a powerful technique for manipulating and controlling the structure of BCP...... thin films, e.g., by healing defects, by altering the orientation of the microdomains and by changing the morphology. Due to high time resolution and compatibility with SVA environments, grazing-incidence small-angle X-ray scattering (GISAXS) is an indispensable technique for studying the SVA process......, providing information of the BCP thin film structure both laterally and along the film normal. Especially, state-of-the-art combined GISAXS/SVA setups at synchrotron sources have facilitated in situ and real-time studies of the SVA process with a time resolution of a few seconds, giving important insight...

  2. Domains in Ferroic Crystals and Thin Films

    CERN Document Server

    Tagantsev, Alexander K; Fousek, Jan

    2010-01-01

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

  3. Nanostructured thin films and coatings mechanical properties

    CERN Document Server

    2010-01-01

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

  4. Solid surfaces, interfaces and thin films

    CERN Document Server

    Lüth, Hans

    2015-01-01

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

  5. Solid Surfaces, Interfaces and Thin Films

    CERN Document Server

    Lüth, Hans

    2010-01-01

    This book emphasises both experimental and theoretical aspects of surface, interface and thin film physics. As in previous editions the preparation of surfaces and thin films, their atomic and morphological, their vibronic and electronic properties as well as fundamentals of adsorption are treated. Because of their importance in modern information technology and nanostructure physics particular emphasis is paid to electronic surface and interface states, semiconductor space charge layers and heterostructures as well as to superconductor/semiconductor interfaces and magnetic thin films. The latter topic was significantly extended in this new edition by more details about the giant magnetoresistance and a section about the spin-transfer torque mechanism including one new problem as exercise. Two new panels about Kerr-effect and spin-polarized scanning tunnelling microscopy were added, too. Furthermore, the meanwhile important group III-nitride surfaces and high-k oxide/semiconductor interfaces are shortly discu...

  6. Capillary stress in microporous thin films

    Energy Technology Data Exchange (ETDEWEB)

    Samuel, J.; Hurd, A.J.; Frink, L.J.D.; Swol, F. van [Sandia National Labs., Albuquerque, NM (United States); Brinker, C.J. [Sandia National Labs., Albuquerque, NM (United States). Ceramic Processing Science Dept.]|[Univ. of New Mexico, Albuquerque, NM (United States). Center for Micro Engineering Ceramics; Raman, N.K. [Univ. of New Mexico, Albuquerque, NM (United States). Center for Micro Engineered Ceramics

    1996-06-01

    Development of capillary stress in porous xerogels, although ubiquitous, has not been systematically studied. The authors have used the beam bending technique to measure stress isotherms of microporous thin films prepared by a sol-gel route. The thin films were prepared on deformable silicon substrates which were then placed in a vacuum system. The automated measurement was carried out by monitoring the deflection of a laser reflected off the substrate while changing the overlying relative pressure of various solvents. The magnitude of the macroscopic bending stress was found to reach a value of 180 MPa at a relative pressure of methanol, P/Po = 0.001. The observed stress is determined by the pore size distribution and is an order of magnitude smaller in mesoporous thin films. Density Functional Theory (DFT) indicates that for the microporous materials, the stress at saturation is compressive and drops as the relative pressure is reduced.

  7. Plasmonic modes in thin films: quo vadis?

    Directory of Open Access Journals (Sweden)

    Antonio ePolitano

    2014-07-01

    Full Text Available Herein, we discuss the status and the prospect of plasmonic modes in thin films. Plasmons are collective longitudinal modes of charge fluctuation in metal samples excited by an external electric field. Surface plasmons (SPs are waves that propagate along the surface of a conductor with applications in magneto-optic data storage, optics, microscopy, and catalysis. In thin films the electronic response is influenced by electron quantum confinement. Confined electrons modify the dynamical screening processes at the film/substrate interface by introducing novel properties with potential applications and, moreover, they affect both the dispersion relation of SP frequency and the damping processes of the SP.Recent calculations indicate the emergence of acoustic surface plasmons (ASP in Ag thin films exhibiting quantum well states and in graphene films. The slope of the dispersion of ASP decreases with film thickness. We also discuss open issues in research on plasmonic modes in graphene/metal interfaes.

  8. Vibration welding system with thin film sensor

    Science.gov (United States)

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

    2014-03-18

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

  9. Device application of AgGa0.5In0.5Se2 thin films deposited by thermal sequential stacked layer method

    Science.gov (United States)

    Coşkun, E.; Güllü, H. H.; Parlak, M.

    2014-12-01

    An In/n-AgGa0.5In0.5Se2/p-Si/Al heterostructure was produced by thermal sequential stacked layer deposition method and the device characteristics were investigated. The compositional analysis showed that the depositions of the intended stoichiometric composition of AgGa0.5In0.5Se2 structure were obtainable by controlling and providing the necessary deposition conditions during the deposition processes. By means of the room temperature Hall effect and transmission measurements, the carrier concentration and optical band gap values were determined as 9× {{10}15} cm-3 and 1.65 eV, respectively. In addition, temperature-dependent current-voltage (I-V) and the room temperature capacitance-voltage (C-V) measurements of this heterostructure were carried out. The rectification factor was obtained as about 104 at 1.20 V for all sample temperatures. Depending on the change in the temperature, the series and shunt resistances were calculated as 101 and 106 Ω, respectively. The studies on the current transport mechanisms showed that there were two different mechanisms at two different voltage regions: tunneling enhanced recombination mechanism in the voltage range of 0.08 and 0.30 V and the space charge limited current mechanism in the voltage range of 0.30 and 0.60 V. The barrier height, built-in potential and interface states density of the deposited heterostructure were also calculated and discussed.

  10. Manufacture of GdBa2Cu3O7−x Superconducting Thin Films Using High-Thermal-Stability Precursors Playing the Role of Intermediate-Phase Grain-Growth Inhibitors

    DEFF Research Database (Denmark)

    Tang, Xiao; He, Dong; Yue, Zhao

    2014-01-01

    We have developed a fluorine-free metal–organic decomposition method using acrylic acid as the solvent for the synthesis of GdBCO superconducting thin films. Commonly used propionic acid was also used to make a comparison with acrylic acid. Acrylic acid was found to be polymerized during drying, ...

  11. Electrochemical fabrication of nanoporous polypyrrole thin films

    International Nuclear Information System (INIS)

    Li Mei; Yuan Jinying; Shi Gaoquan

    2008-01-01

    Polypyrrole thin films with pores in nanometer scale were synthesized by direct electrochemical oxidation of pyrrole in a mixed electrolyte of isopropyl alcohol, boron trifluoride diethyl etherate, sodium dodecylsulfonate and poly(ethylene glycol) using well-aligned ZnO nanowires arrays as templates. The thin films exhibit high conductivity of ca. σ rt ∼ 20.5 s/cm and can be driven to bend during redox processes in 1.0 M lithium perchlorate aqueous solution. The movement rate of an actuator based on this nanoporous film was measured to be over 90 o /s at a driving potential of 0.8 V (vs. Ag/AgCl)

  12. The future of rare earth thin films

    International Nuclear Information System (INIS)

    Gasgnier, M.

    1986-01-01

    This paper presents some recent applications in the rare earth field and also may be, some of the future new developments of laboratory works. The field of investigations will concern only materials which contain at least one rare earth element (lanthanide series, from La to Lu, Sc and Y). After a rapid survey of the experimental procedures relative to the preparation and to the analytical characterization of thin films, technological applications in various fields of research are briefly reviewed: for polycrystalline metals (superconductors, neutron absorption, photovoltaic effect...), alloys (hydrogen storage, superconductors) and compounds (target for intense neutron sources, radiology...) and for amorphous magnetic thin films. 81 refs [fr

  13. Intrinsically conductive polymer thin film piezoresistors

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  14. Micro-sensor thin-film anemometer

    Science.gov (United States)

    Sheplak, Mark (Inventor); McGinley, Catherine B. (Inventor); Spina, Eric F. (Inventor); Stephens, Ralph M. (Inventor); Hopson, Jr., Purnell (Inventor); Cruz, Vincent B. (Inventor)

    1996-01-01

    A device for measuring turbulence in high-speed flows is provided which includes a micro-sensor thin-film probe. The probe is formed from a single crystal of aluminum oxide having a 14.degree. half-wedge shaped portion. The tip of the half-wedge is rounded and has a thin-film sensor attached along the stagnation line. The bottom surface of the half-wedge is tilted upward to relieve shock induced disturbances created by the curved tip of the half-wedge. The sensor is applied using a microphotolithography technique.

  15. Analysis Crystal Structure of Thin Films Bazr0.2ti0.8o3 Which Have Deposited by Sol Gel Method

    OpenAIRE

    I., Yofentina; V., Viska I; Hikam, M; S., Bambang; M., Alfan; P., Wahyu

    2011-01-01

    Fabrication of BaZr0.2Ti0.8O3 thin film on Si substrate by sol gel method use spin coater has been done successfully. Bariumasetat, zirconiumisoproponol, titaniumisopropoksid were used as deposition components BZT thin film. Asetat acid and etylen glycol were used as solvent. There are three basic principles of thin film fabrication by sol gel method, i.e. chemical process (Solvent fabrication), thin film deposition use spin coater, and thermal process (annealing). The layers number variation...

  16. Schottky contact analysis of photovoltaic chalcopyrite thin film absorbers

    International Nuclear Information System (INIS)

    Schlenker, E.; Mertens, V.; Parisi, J.; Reineke-Koch, R.; Koentges, M.

    2007-01-01

    Current-voltage and capacitance-voltage measurements serve to analyze thermally evaporated Al Schottky contacts on Cu(In, Ga)Se 2 based photovoltaic thin film devices, either taken as grown or etched in a bromine-methanol solution. The characteristics of the Schottky contacts on the as-grown films give evidence for some dielectric layer developing between the metal and the semiconductor. Etching the semiconductor surface prior to evaporation of the Al front contact yields a pure metal-semiconductor behavior, including effects that can be attributed to an additional diode at the Mo contact. Simulations confirm the experimental results

  17. Improved damp heat stability of Ga-Doped ZnO thin film by pretreatment of the polyethylene terephthalate substrate

    Science.gov (United States)

    Kim, B. B.; Seo, S. G.; Lim, Y. S.; Choi, H.-S.; Seo, W.-S.; Park, H.-H.

    2013-09-01

    A study on the damp heat stability of transparent conducting ZnO thin film grown on a polyethylene terephthalate substrate (PET) is reported. By thermal annealing of the PET substrate at 100°C with Ar flow in a vacuum chamber prior to the sputtering growth of Ga-doped ZnO (GZO) thin film, significantly enhanced damp heat stability was achieved at 60°C with a 90% relative humidity. Electrical and structural characterizations of the GZO thin films were carried out and the effects of the pretreatment on the improved damp heat stability are discussed.

  18. Morphology and microstructure of picene thin-films for air-operating transistors

    Energy Technology Data Exchange (ETDEWEB)

    Diallo, Abdou Karim [Aix Marseille Université, CNRS, CINaM UMR 7325, 13288 Marseille (France); Kurihara, Ryouta [Graduate School of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551 (Japan); Yoshimoto, Noriyuki, E-mail: yoshimoto@iwate-u.ac.jp [Graduate School of Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551 (Japan); Videlot-Ackermann, Christine, E-mail: videlot@cinam.univ-mrs.fr [Aix Marseille Université, CNRS, CINaM UMR 7325, 13288 Marseille (France)

    2014-09-30

    Graphical abstract: - Highlights: • Vacuum deposition of picene active layer for devices operating in air. • Morphology and microstructure of picene thin-films. • Low temperature thermal annealing for air-performing transistors based on picene. - Abstract: Picene, a p-type organic semiconductor, was involved as active layer in organic thin film transistors (OTFTs). Picene thin films were realized by vacuum evaporation on gate dielectrics based on bare silicon dioxide (SiO{sub 2}) or coated with polymethyl-methacrylate (PMMA). Assisted by a controlled post-deposition annealing at low temperature (<100 °C), OTFTs were characterized in air to provide a hole mobility up to 0.2 cm{sup 2}/V s. Thin-film morphology and microstructure were studied in details by atomic force microscopy (AFM) and X-ray film diffractometry (XRD) before and after the post-annealing as thickness and vacuum conditions dependences. While any molecular reorganization was induced by such thermal post-treatment, the unavoidable presence of H{sub 2}O molecules in air and their diffusion in thin films were consistently reduced to offer air-operating OTFTs.

  19. Thin films of molecular materials synthesized from fisher's carbene ferrocenyl: Film formation and electrical properties

    International Nuclear Information System (INIS)

    Sanchez-Vergara, M.E.; Ortiz, A.; Alvarez-Toledano, C.; Moreno, A.; Alvarez, J.R.

    2008-01-01

    The synthesis of materials from Fisher's carbene ferrocenyl of the elements chromium, molybdenum and tungsten was carried out. The Fisher's compounds that were synthesized included the following combinations of two different metallic atoms: iron with chromium, iron with molybdenum and iron with tungsten. The molecular solids' preparation was done in electro-synthesis cells with platinum electrodes. Thin films were prepared by vacuum thermal evaporation on quartz substrates and crystalline silicon wafers. Pellets and thin films from these compounds were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy, atomic force microscopy and ellipsometry. The powder and thin films synthesized from these materials show the same intra-molecular bonds shown by infrared spectroscopy results, suggesting that thermal evaporation does not alter these bonds in spite of the thin films being amorphous, in contrast with other bimetallic complexes where material decomposition occurs. The differences in the conductivity values of the prepared films are very small, so they may be attributed to the different metallic ions employed in each case. The tungsten complex exhibits a higher conductivity than the molybdenum and chromium complexes at room temperature. Electrical conductivity values found for thin films are higher than for pellets made of the same molecular materials

  20. Characterization of layer-by-layer self-assembled carbon nanotube multilayer thin films

    International Nuclear Information System (INIS)

    Xue Wei; Cui Tianhong

    2007-01-01

    Single-walled carbon nanotube (SWNT) multilayer thin films are deposited on silicon substrates with layer-by-layer self-assembly. The structural, mechanical, electrical, and thermal properties of the thin films are investigated using quartz crystal microbalance (QCM), nanoindentation, and rapid thermal annealing techniques, respectively. Scanning electron microscopy inspection shows that the SWNT multilayer is formed through a dense network of nanotube bundles. Based on the QCM measurement, the volume and mass ratios of SWNTs in the multilayer are calculated as 63.2% and 75%, respectively. Nanoindentation on the SWNT thin film shows that its Young's modulus and hardness are approximately 17 and 0.6 GPa, respectively. Current-voltage (I-V) and four-point probe techniques are used to study the electrical properties of the SWNT thin film after being heated at different temperatures. The conductance of the SWNT thin film at 300 deg. C is measured as 2.29 mS, which is 50 times higher than that at room temperature (0.045 mS)

  1. Micro Structural Analysis of In2S3 Thin Films by Raman Spectroscopy

    Science.gov (United States)

    Izadneshana, H.; Gremenok, V. F.

    2014-11-01

    In2S3 thin films with different thicknesses were deposited on glass substrates using the thermal evaporation method. The as-deposited films were annealed in vacuum at 330 and 400°C for 30 and 60 min. We used Raman spectroscopy and X-ray diffraction to evaluate the effect of thermal treatment on the film structures. Raman active modes that can be classified as 9A1 and 14E modes have been observed in the Raman spectra of the In2S3 thin films. Variations in the Raman shift and bandwidth of different In2S3 thin films reveal the influence of the annealing effect. Results of Raman spectroscopy and XRD show that the annealing effect changes the crystallization phase from tetragonal to cubic at high temperatures.

  2. Inelastic deformation of plasma polymerised thin films facilitated by transient dense plasma focus irradiation

    Science.gov (United States)

    Grant, Daniel S.; Rawat, Rajdeep S.; Bazaka, Kateryna; Jacob, Mohan V.

    2017-09-01

    The high degree of crosslinking present in plasma polymerised thin films, coupled with their high molecular weight, imbues these films with properties similar to those of thermosetting polymers. For instance, such films tend to be relatively hard, insoluble, and to date have not exhibited plasticity when subjected to elevated temperatures. In this paper it is demonstrated that plasma polymers can, in fact, undergo plastic deformation in response to the application of extremely short-lived thermal treatment delivered by a dense plasma focus device, as evidenced by the evolution of bubble-like structures from the thin film. This finding suggests new avenues for texturing plasma thin films, and synthesising cavities that may find utility as thermal insulators or domains for material encapsulation.

  3. Solvent-Free Toner Printing of Organic Semiconductor Layer in Flexible Thin-Film Transistors

    Science.gov (United States)

    Sakai, Masatoshi; Koh, Tokuyuki; Toyoshima, Kenji; Nakamori, Kouta; Okada, Yugo; Yamauchi, Hiroshi; Sadamitsu, Yuichi; Shinamura, Shoji; Kudo, Kazuhiro

    2017-07-01

    A solvent-free printing process for printed electronics is successfully developed using toner-type patterning of organic semiconductor toner particles and the subsequent thin-film formation. These processes use the same principle as that used for laser printing. The organic thin-film transistors are prepared by electrically distributing the charged toner onto a Au electrode on a substrate film, followed by thermal lamination. The thermal lamination is effective for obtaining an oriented and crystalline thin film. Toner printing is environmentally friendly compared with other printing technologies because it is solvent free, saves materials, and enables easy recycling. In addition, this technology simultaneously enables both wide-area and high-resolution printing.

  4. Tailored piezoelectric thin films for energy harvester

    NARCIS (Netherlands)

    Wan, X.

    2013-01-01

    Piezoelectric materials are excellent materials to transfer mechanical energy into electrical energy, which can be stored and used to power other devices. PiezoMEMS is a good way to combine silicon wafer processing and piezoelectric thin film technology and lead to a variety of miniaturized and

  5. Humidity sensing characteristics of hydrotungstite thin films

    Indian Academy of Sciences (India)

    Wintec

    variety of tungstate materials, such as thick-film manga- nese tungstate, have been applied as humidity sensors. (Qu and Mayer 1997). The humidity sensing characteristics of bulk metal oxide–tungsten oxide systems have also been studied in the literature (Ichinose 1993). Thin films of tungsten oxide have been prepared ...

  6. Reliability growth of thin film resistors contact

    Directory of Open Access Journals (Sweden)

    Lugin A. N.

    2010-10-01

    Full Text Available Necessity of resistive layer growth under the contact and in the contact zone of resistive element is shown in order to reduce peak values of current flow and power dissipation in the contact of thin film resistor, thereby to increase the resistor stability to parametric and catastrophic failures.

  7. Lattice Mismatch in Crystalline Nanoparticle Thin Films.

    Science.gov (United States)

    Gabrys, Paul A; Seo, Soyoung E; Wang, Mary X; Oh, EunBi; Macfarlane, Robert J; Mirkin, Chad A

    2018-01-10

    For atomic thin films, lattice mismatch during heteroepitaxy leads to an accumulation of strain energy, generally causing the films to irreversibly deform and generate defects. In contrast, more elastically malleable building blocks should be better able to accommodate this mismatch and the resulting strain. Herein, that hypothesis is tested by utilizing DNA-modified nanoparticles as "soft," programmable atom equivalents to grow a heteroepitaxial colloidal thin film. Calculations of interaction potentials, small-angle X-ray scattering data, and electron microscopy images show that the oligomer corona surrounding a particle core can deform and rearrange to store elastic strain up to ±7.7% lattice mismatch, substantially exceeding the ±1% mismatch tolerated by atomic thin films. Importantly, these DNA-coated particles dissipate strain both elastically through a gradual and coherent relaxation/broadening of the mismatched lattice parameter and plastically (irreversibly) through the formation of dislocations or vacancies. These data also suggest that the DNA cannot be extended as readily as compressed, and thus the thin films exhibit distinctly different relaxation behavior in the positive and negative lattice mismatch regimes. These observations provide a more general understanding of how utilizing rigid building blocks coated with soft compressible polymeric materials can be used to control nano- and microstructure.

  8. A thin film magnetoresistive angle detector

    NARCIS (Netherlands)

    Eijkel, C.J.M.; Wieberdink, Johan W.; Fluitman, J.H.J.; Popma, T.J.A.; Groot, Peter; Leeuwis, Henk

    1990-01-01

    An overview is given of the results of our research on a contactless angle detector based on the anisotropic magnetoresistance effect (AMR effect) in a permalloy thin film. The results of high-temperature annealing treatment of the pemalloy film are discussed. Such a treatment suppresses the effects

  9. Thermoviscoelastic models for polyethylene thin films

    DEFF Research Database (Denmark)

    Li, Jun; Kwok, Kawai; Pellegrino, Sergio

    2016-01-01

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

  10. Incipient plasticity in metallic thin films

    NARCIS (Netherlands)

    Soer, W. A.; De Hosson, J. Th. M.; Minor, A. M.; Shan, Z.; Asif, S. A. Syed; Warren, O. L.

    2007-01-01

    The authors have compared the incipient plastic behaviors of Al and Al-Mg thin films during indentation under load control and displacement control. In Al-Mg, solute pinning limits the ability of dislocations to propagate into the crystal and thus substantially affects the appearance of plastic

  11. Thin film hydrous metal oxide catalysts

    Science.gov (United States)

    Dosch, Robert G.; Stephens, Howard P.

    1995-01-01

    Thin film (metal oxide catalysts are prepared by 1) synthesis of a hydrous metal oxide, 2) deposition of the hydrous metal oxide upon an inert support surface, 3) ion exchange with catalytically active metals, and 4) activating the hydrous metal oxide catalysts.

  12. Polyaniline. Thin films and colloidal dispersions

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Sapurina, I.

    2005-01-01

    Roč. 77, č. 5 (2005), s. 815-826 ISSN 0033-4545 R&D Projects: GA MŠk ME 539; GA AV ČR IAA4050313 Grant - others:IUPAC project 2002-019-1-400 Keywords : polyaniline * thin films * dispersions Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.679, year: 2005

  13. A ferroelectric transparent thin-film transistor

    NARCIS (Netherlands)

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

    1996-01-01

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

  14. Flexoelectricity in barium strontium titanate thin film

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-10-06

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

  15. Flexoelectricity in barium strontium titanate thin film

    International Nuclear Information System (INIS)

    Kwon, Seol Ryung; Huang, Wenbin; Yuan, Fuh-Gwo; Jiang, Xiaoning; Shu, Longlong; Maria, Jon-Paul

    2014-01-01

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

  16. Functional planar thin film optical waveguide lasers

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Miroslav

    2012-01-01

    Roč. 9, č. 2 (2012), 91-99 ISSN 1612-2011 R&D Projects: GA ČR(CZ) GAP106/10/1477 Institutional research plan: CEZ:AV0Z10100522 Keywords : waveguide laser * planar waveguides * thin films * pulsed laser deposition * optical waveguides * laser materials Subject RIV: BH - Optics, Masers, Lasers Impact factor: 7.714, year: 2012

  17. A generalized theory of thin film growth

    Science.gov (United States)

    Du, Feng; Huang, Hanchen

    2018-03-01

    This paper reports a theory of thin film growth that is generalized for arbitrary incidence angle during physical vapor deposition in two dimensions. The accompanying kinetic Monte Carlo simulations serve as verification. A special theory already exists for thin film growth with zero incidence angle, and another theory also exists for nanorod growth with a glancing angle. The theory in this report serves as a bridge to describe the transition from thin film growth to nanorod growth. In particular, this theory gives two critical conditions in analytical form of critical coverage, ΘI and ΘII. The first critical condition defines the onset when crystal growth or step dynamics stops following the wedding cake model for thin film growth. The second critical condition defines the onset when multiple-layer surface steps form to enable nanorod growth. Further, this theory also reveals a critical incidence angle, below which nanorod growth is impossible. The critical coverages, together with the critical incidence angle, defines a phase diagram of thin growth versus nanorod growth.

  18. Practical design and production of optical thin films

    CERN Document Server

    Willey, Ronald R

    2002-01-01

    Fundamentals of Thin Film Optics and the Use of Graphical Methods in Thin Film Design Estimating What Can Be Done Before Designing Fourier Viewpoint of Optical Coatings Typical Equipment for Optical Coating Production Materials and Process Know-How Process Development Monitoring and Control of Thin Film Growth Appendix: Metallic and Semiconductor Material Graphs Author IndexSubject Index

  19. Density functional study of ferromagnetism in alkali metal thin films

    Indian Academy of Sciences (India)

    model (UJM), and it is argued that within LSDA or GGA, alkali metal thin films cannot be claimed to have an FM ground state. Relevance of these results to the experiments on transition metal-doped alkali metal thin films and bulk hosts are also discussed. Keywords. Alkali metal; thin films; magnetism; density functional ...

  20. Optical and electrical properties of nickel xanthate thin films

    Indian Academy of Sciences (India)

    Keywords. Nickel xanthate thin film; organometallic thin film; chemical bath deposition. Abstract. Nickel xanthate thin films (NXTF) were successfully deposited by chemical bath deposition, on to amorphous glass substrates, as well as on - and -silicon, indium tin oxide and poly(methyl methacrylate). The structure of the ...

  1. Enhanced thermoelectric properties of phase-separating bismuth selenium telluride thin films via a two-step method

    Energy Technology Data Exchange (ETDEWEB)

    Takashiri, Masayuki, E-mail: takashiri@tokai-u.jp; Kurita, Kensuke [Department of Materials Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Hagino, Harutoshi; Miyazaki, Koji [Department of Mechanical and Control Engineering, Kyushu Institute of Technology, 1-1 Sensui, Tobata-ku, Kitakyushu 804-8550 (Japan); Tanaka, Saburo [Department of Mechanical Engineering, College of Engineering, Nihon University, 1 Nakagawara, Tokusada, Tamuramachi, Koriyama, Fukushima 963-8642 (Japan)

    2015-08-14

    A two-step method that combines homogeneous electron beam (EB) irradiation and thermal annealing has been developed to enhance the thermoelectric properties of nanocrystalline bismuth selenium telluride thin films. The thin films, prepared using a flash evaporation method, were treated with EB irradiation in a N{sub 2} atmosphere at room temperature and an acceleration voltage of 0.17 MeV. Thermal annealing was performed under Ar/H{sub 2} (5%) at 300 °C for 60 min. X-ray diffraction was used to determine that compositional phase separation between bismuth telluride and bismuth selenium telluride developed in the thin films exposed to higher EB doses and thermal annealing. We propose that the phase separation was induced by fluctuations in the distribution of selenium atoms after EB irradiation, followed by the migration of selenium atoms to more stable sites during thermal annealing. As a result, thin film crystallinity improved and mobility was significantly enhanced. This indicates that the phase separation resulting from the two-step method enhanced, rather than disturbed, the electron transport. Both the electrical conductivity and the Seebeck coefficient were improved following the two-step method. Consequently, the power factor of thin films that underwent the two-step method was enhanced to 20 times (from 0.96 to 21.0 μW/(cm K{sup 2}) that of the thin films treated with EB irradiation alone.

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

    International Nuclear Information System (INIS)

    Krauss, A.R.; Rangaswamy, M.; Lin, Yuping; Gruen, D.M.; Schultz, J.A.; Schmidt, H.K.; Chang, R.P.H.

    1992-01-01

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

  3. Studies on nonlocal optical nonlinearity of Sr–CuO–polyvinyl alcohol nanocomposite thin films

    International Nuclear Information System (INIS)

    Tamgadge, Y.S.; Talwatkar, S.S.; Sunatkari, A.L.; Pahurkar, V.G.; Muley, G.G.

    2015-01-01

    Thermally induced nonlocal nonlinear optical properties of strontium (Sr) doped CuO-polyvinyl alcohol (PVA) nanocomposite thin films under continuous wave Helium–Neon laser illumination are investigated by single beam Z-scan method. Undoped and Sr doped CuO nanoparticles (NPs) using L-arginine as surface modifying agent have been synthesized by wet chemical method and their thin films with PVA as host matrix have been obtained by spin coating technique. Structure, morphology and purity of prepared CuO NPs and thin films have been studied by X-ray diffraction, high-resolution transmission electron microscopy, field emission scanning electron microscopy and energy dispersive X-ray absorption spectroscopy. Fourier transform infra-red spectrum attests the role of L-arginine as surface modifier and ultraviolet–visible absorption studies reveal that the excitonic absorption wavelengths are blue shifted for strontium doped CuO NPs. Sr doped CuO NPs with average particle size of 7 nm and calculated optical band gap up to 2.54 eV have been reported. All Sr doped CuO–PVA nanocomposite thin films show enhanced nonlinear refraction and absorption best suited for optical limiting applications. Observed effects have been attributed to thermal lensing effect. - Highlights: • Pure and strontium doped CuO–polyvinyl alcohol nanocomposite thin films are prepared. • Z-scan studies of thin films are performed under continuous wave helium–neon laser. • Enhanced values of third order nonlinear optical coefficients are obtained for all films. • Thermally induced self-defocusing and reverse saturable absorption have been discussed.

  4. Studies on nonlocal optical nonlinearity of Sr–CuO–polyvinyl alcohol nanocomposite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tamgadge, Y.S. [Department of Physics, Mahatma Fule Arts, Commerce and S C Science Mahavidyalaya, Warud, Dist. Amravati (MS), 444906 (India); Talwatkar, S.S. [Department of Physics, D K Marathe and N G Acharya College, Chembur, Mumbai (MS) 440071 (India); Sunatkari, A.L. [Department of Physics, Siddharth College of Arts, Science and Commerce, Fort, Mumbai (MS) 440001 (India); Pahurkar, V.G. [Department of Physics, Sant Gadge Baba Amravati University, Amravati (MS), 444602 (India); Muley, G.G., E-mail: gajananggm@yahoo.co.in [Department of Physics, Sant Gadge Baba Amravati University, Amravati (MS), 444602 (India)

    2015-11-30

    Thermally induced nonlocal nonlinear optical properties of strontium (Sr) doped CuO-polyvinyl alcohol (PVA) nanocomposite thin films under continuous wave Helium–Neon laser illumination are investigated by single beam Z-scan method. Undoped and Sr doped CuO nanoparticles (NPs) using L-arginine as surface modifying agent have been synthesized by wet chemical method and their thin films with PVA as host matrix have been obtained by spin coating technique. Structure, morphology and purity of prepared CuO NPs and thin films have been studied by X-ray diffraction, high-resolution transmission electron microscopy, field emission scanning electron microscopy and energy dispersive X-ray absorption spectroscopy. Fourier transform infra-red spectrum attests the role of L-arginine as surface modifier and ultraviolet–visible absorption studies reveal that the excitonic absorption wavelengths are blue shifted for strontium doped CuO NPs. Sr doped CuO NPs with average particle size of 7 nm and calculated optical band gap up to 2.54 eV have been reported. All Sr doped CuO–PVA nanocomposite thin films show enhanced nonlinear refraction and absorption best suited for optical limiting applications. Observed effects have been attributed to thermal lensing effect. - Highlights: • Pure and strontium doped CuO–polyvinyl alcohol nanocomposite thin films are prepared. • Z-scan studies of thin films are performed under continuous wave helium–neon laser. • Enhanced values of third order nonlinear optical coefficients are obtained for all films. • Thermally induced self-defocusing and reverse saturable absorption have been discussed.

  5. Electric Field Stiffening Effect in c-Oriented Aluminum Nitride Piezoelectric Thin Films.

    Science.gov (United States)

    Chen, Cong; Shang, Zhengguo; Gong, Jia; Zhang, Feng; Zhou, Hong; Tang, Bin; Xu, Yi; Zhang, Chi; Yang, Ya; Mu, Xiaojing

    2018-01-17

    Aluminum nitride offers unique material advantages for the realization of ultrahigh-frequency acoustic devices attributed to its high ratio of stiffness to density, compatibility with harsh environments, and superior thermal properties. Although, to date, aluminum nitride thin films have been widely investigated regarding their electrical and mechanical characteristics under alternating small signal excitation, their ultrathin nature under large bias may also provide novel and useful properties. Here, we present a comprehensive investigation of electric field stiffening effect in c-oriented aluminum nitride piezoelectric thin films. By analyzing resonance characteristics in a 2.5 GHz aluminum nitride-based film bulk acoustic resonator, we demonstrate an up to 10% linear variation in the equivalent stiffness of aluminum nitride piezoelectric thin films when an electric field was applied from -150 to 150 MV/m along the c-axis. Moreover, for the first time, an atomic interaction mechanism is proposed to reveal the nature of electric field stiffening effect, suggesting that the nonlinear variation of the interatomic force induced by electric field modulation is the intrinsic reason for this phenomenon in aluminum nitride piezoelectric thin films. Our work provides vital experimental data and effective theoretical foundation for electric field stiffening effect in aluminum nitride piezoelectric thin films, indicating the huge potential in tunable ultrahigh-frequency microwave devices.

  6. Synthesis and characterization of nanostructured strontium hexaferrite thin films by the sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Masoudpanah, S.M., E-mail: masoodpanah@ut.ac.ir [Center of Excellence for Magnetic Materials, School of Metallurgy and Materials, University of Tehran, Tehran (Iran, Islamic Republic of); Seyyed Ebrahimi, S.A. [Center of Excellence for Magnetic Materials, School of Metallurgy and Materials, University of Tehran, Tehran (Iran, Islamic Republic of)

    2012-07-15

    Nanostructured single phase strontium hexaferrite, SrFe{sub 12}O{sub 19}, thin films have been synthesized on the (100) silicon substrate using a spin coating sol-gel process. The thin films with various Fe/Sr molar ratios of 8-12 were calcined at different temperatures from 500 to 900 Degree-Sign C. The composition, microstructure and magnetic properties of the SrFe{sub 12}O{sub 19} thin films were characterized using Fourier transform infrared spectroscopy, differential thermal analysis, thermogravimetry, X-ray diffraction, electron microscopy and vibrating sample magnetometer. The results showed that the optimum molar ratio for Fe/Sr was 10 at which the lowest calcination temperature to obtain the single phase strontium hexaferrite thin film was 800 Degree-Sign C. The magnetic measurements revealed that the sample with Fe/Sr molar ratio of 10, exhibited higher saturation magnetization (267.5 emu/cm{sup 3}) and coercivity (4290 Oe) in comparison with those synthesized under other Fe/Sr molar ratios. - Highlights: Black-Right-Pointing-Pointer Preparing of strontium hexaferrite thin film by sol-gel spin coating. Black-Right-Pointing-Pointer The films prepared from the solutions with different Fe/Sr=8-12. Black-Right-Pointing-Pointer The film with Fe/Sr=10 has the lowest calcination temperature, 800 Degree-Sign c. Black-Right-Pointing-Pointer The film with Fe/Sr=10 has simultaneously maximum saturation magnetization and coercivity.

  7. Studies on influence of light on fluorescence of Tris-(8-hydroxyquinoline)aluminum thin films

    Science.gov (United States)

    Thangaraju, K.; Amaladass, P.; Bharathi, K. Shanmuga; Mohanakrishnan, A. K.; Narayanan, V.; Kumar, J.

    2009-03-01

    Tris-(8-hydroxyquinoline)aluminum (Alq 3) thin films, the most widely used electron transport/emissive material in the organic electroluminescent (EL) devices, have been deposited on glass substrates by thermal evaporation process. Alq 3 thin films were exposed to light for various time periods under normal ambient. The fluorescence of as-prepared and light exposed Alq 3 thin films and formation of luminescent quencher have been studied using fluorescence, Mass, MALDI-ToF-MS, 1H & 13C NMR, and FT-IR spectroscopy. It is observed that among the three 8-hydroxyquinoline (HQ) units in Alq 3 molecule, one HQ unit is affected during the light exposure in the normal ambient. It is found that the affected resultant Alq 3 molecule containing the carbonyl group acts as fluorescent quencher and the energy of excitons in the Alq 3 molecule in the light exposed Alq 3 thin films can be non-radiatively transferred to the neighboring fluorescent quencher, quenching the fluorescence of light exposed Alq 3 thin films in the normal ambient.

  8. Synthesis of bimetallic nanostructures by nanosecond laser ablation of multicomponent thin films in water

    Science.gov (United States)

    Nikov, R. G.; Nedyalkov, N. N.; Atanasov, P. A.; Karashanova, D. B.

    2018-03-01

    The paper presents results on nanosecond laser ablation of thin films immersed in a liquid. The thin films were prepared by consecutive deposition of layers of different metals by thermal evaporation (first layer) and classical on-axis pulsed laser deposition (second layer); Ni/Au, Ag/Au and Ni/Ag thin films were thus deposited on glass substrates. The as-prepared films were then placed at the bottom of a glass vessel filled with double distilled water and irradiated by nanosecond laser pulses delivered by a Nd:YAG laser system at λ = 355 nm. This resulted in the formation of colloids of the thin films’ material. We also compared the processes of ablation of a bulk target and a thin film in the liquid by irradiating a Au target and a Au thin film by the same laser wavelength and fluence (λ = 355 nm, F = 5 J/cm2). The optical properties of the colloids were evaluated by optical transmittance measurements in the UV– VIS spectral range. Transmission electron microscopy was employed to estimate the particles’ size distribution.

  9. Superhydrophobic Ag decorated ZnO nanostructured thin film as effective surface enhanced Raman scattering substrates

    Science.gov (United States)

    Jayram, Naidu Dhanpal; Sonia, S.; Poongodi, S.; Kumar, P. Suresh; Masuda, Yoshitake; Mangalaraj, D.; Ponpandian, N.; Viswanathan, C.

    2015-11-01

    The present work is an attempt to overcome the challenges in the fabrication of super hydrophobic silver decorated zinc oxide (ZnO) nanostructure thin films via thermal evaporation process. The ZnO nanowire thin films are prepared without any surface modification and show super hydrophobic nature with a contact angle of 163°. Silver is further deposited onto the ZnO nanowire to obtain nanoworm morphology. Silver decorated ZnO (Ag@ZnO) thin films are used as substrates for surface enhanced Raman spectroscopy (SERS) studies. The formation of randomly arranged nanowire and silver decorated nanoworm structure is confirmed using FESEM, HR-TEM and AFM analysis. Crystallinity and existence of Ag on ZnO are confirmed using XRD and XPS studies. A detailed growth mechanism is discussed for the formation of the nanowires from nanobeads based on various deposition times. The prepared SERS substrate reveals a reproducible enhancement of 3.082 × 107 M for Rhodamine 6G dye (R6G) for 10-10 molar concentration per liter. A higher order of SERS spectra is obtained for a contact angle of 155°. Thus the obtained thin films show the superhydrophobic nature with a highly enhanced Raman spectrum and act as SERS substrates. The present nanoworm morphology shows a new pathway for the construction of semiconductor thin films for plasmonic studies and challenges the orderly arranged ZnO nanorods, wires and other nano structure substrates used in SERS studies.

  10. Reversible wettability of nanostructured ZnO thin films by sol-gel method

    Science.gov (United States)

    Lü, Jianguo; Huang, Kai; Chen, Xuemei; Zhu, Jianbo; Meng, Fanming; Song, Xueping; Sun, Zhaoqi

    2010-05-01

    Nanostructured ZnO thin films were deposited on Si(1 1 1) and quartz substrate by sol-gel method. The thin films were annealed at 673 K, 873 K, and 1073 K for 60 min. Microstructure, surface topography, and water contact angle of the thin films have been measured by X-ray diffractometer, atomic force microscopy, and water contact angle apparatus. XRD results showed that the ZnO thin films are polycrystalline with hexagonal wurtzite structure. AFM studies revealed that rms roughness changes from 2.3 nm to 7.4 nm and the grain size grow up continuously with increasing annealing temperature. Wettability results indicated that hydrophobicity of the un-irradiated ZnO thin films enhances with annealing temperature increase. The hydrophobic ZnO surfaces could be reversibly switched to hydrophilic by alternation of UV illumination and dark storage (thermal treatment). By studying the magnitude and the contact angle reduction rate of the light-induced process, the contribution of surface roughness is discussed.

  11. Intrinsic stress of bismuth oxide thin films: effect of vapour chopping and air ageing

    International Nuclear Information System (INIS)

    Patil, R B; Puri, R K; Puri, V

    2008-01-01

    Bismuth oxide thin films of thickness 1000 A 0 have been prepared by thermal oxidation (in air) of vacuum evaporated bismuth thin films (on glass substrate) at different oxidation temperatures and duration. Both the vapour chopped and nonchopped bismuth oxide thin films showed polycrystalline and polymorphic structure. The monoclinic bismuth oxide was found to be predominant in both the cases. The effect of vapour chopping and air exposure for 40 days on the intrinsic stress of bismuth oxide thin films has been studied. The vapour chopped films showed low (3.92 - 4.80 x 10 9 N/m 2 ) intrinsic stress than those of nonchopped bismuth oxide thin films (5.77 - 6.74 x 10 9 N/m 2 ). Intrinsic stress was found to increase due to air ageing. The effect of air ageing on the vapour chopped films was found low. The vapour chopped films showed higher packing density. Higher the packing density, lower the film will age. The process of chopping vapour flow creates films with less inhomogenety i.e. a low concentration of flaws and non-planar defects which results in lower intrinsic stress

  12. Nanostructured thin film coatings with different strengthening effects

    Directory of Open Access Journals (Sweden)

    Panfilov Yury

    2017-01-01

    Full Text Available A number of articles on strengthening thin film coatings were analyzed and a lot of unusual strengthening effects, such as super high hardness and plasticity simultaneously, ultra low friction coefficient, high wear-resistance, curve rigidity increasing of drills with small diameter, associated with process formation of nanostructured coatings by the different thin film deposition methods were detected. Vacuum coater with RF magnetron sputtering system and ion-beam source and arc evaporator for nanostructured thin film coating manufacture are represented. Diamond Like Carbon and MoS2 thin film coatings, Ti, Al, Nb, Cr, nitride, carbide, and carbo-nitride thin film materials are described as strengthening coatings.

  13. Thin film bismuth iron oxides useful for piezoelectric devices

    Science.gov (United States)

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

    2016-05-31

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

  14. Combined sonochemical/CVD method for preparation of nanostructured carbon-doped TiO{sub 2} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Rasoulnezhad, Hossein [Semiconductor Department, Materials and Energy Research Center (MERC), Karaj (Iran, Islamic Republic of); Kavei, Ghassem, E-mail: kaveighassem@gmail.com [Semiconductor Department, Materials and Energy Research Center (MERC), Karaj (Iran, Islamic Republic of); Ahmadi, Kamran [Semiconductor Department, Materials and Energy Research Center (MERC), Karaj (Iran, Islamic Republic of); Rahimipour, Mohammad Reza [Ceramic Department, Materials and Energy Research Center (MERC), Karaj (Iran, Islamic Republic of)

    2017-06-30

    Highlights: • Combination of sonochemical and CVD methods for preparation of nanostructured carbon-doped TiO{sub 2} thin film on glass substrate, for the first time. • High transparency, monodispersity and homogeneity of the prepared thin films. • Preparation of the carbon-doped TiO{sub 2} thin films with nanorod and nanosphere morphologies. - Abstract: The present work reports the successful synthesis of the nanostructured carbon-doped TiO{sub 2} thin films on glass substrate by combination of chemical vapor deposition (CVD) and ultrasonic methods, for the first time. In this method the ultrasound waves act as nebulizer for converting of sonochemically prepared TiO{sub 2} sol to the mist particles. These mist particles were thermally decomposed in subsequent CVD chamber at 320 °C to produce the carbon-doped TiO{sub 2} thin films. The obtained thin films were characterized by means of X-ray Diffraction (XRD), Raman spectroscopy, diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. The results show that the prepared thin films have anatase crystal structure and nanorod morphology, which calcination of them at 800 °C results in the conversion of nanorods to nanoparticles. In addition, the prepared samples have high transparency, monodispersity and homogeneity. The presence of the carbon element in the structure of the thin films causes the narrowing of the band-gap energy of TiO{sub 2} to about 2.8 eV, which results in the improvement of visible light absorption capabilities of the thin film.

  15. Calibration of thin-film dosimeters irradiated with 80-120 kev electrons

    DEFF Research Database (Denmark)

    Helt-Hansen, J.; Miller, A.; McEwen, M.

    2004-01-01

    A method for calibration of thin-film dosimeters irradiated with 80-120keV electrons has been developed. The method is based on measurement of dose with a totally absorbing graphite calorimeter, and conversion of dose in the graphite calorimeter to dose in the film dosimeter by Monte Carlo...... calculations. A thermal model was developed to estimate the temperature contributions from the air above the calorimeter that is heated by the electron beam. As an example, Riso B3 thin-film dosimeters were calibrated by 80-120 keV electron irradiation and compared with a calibration carried out at 10 Me...

  16. XPS analysis of the activation process in non-evaporable getter thin films

    CERN Document Server

    Lozano, M

    2000-01-01

    The surface activation process of sputter-coated non-evaporable getter (NEG) thin films based on Ti-Zr and Ti-Zr-V alloys has been studied in situ by means of X-ray photoelectron spectroscopy. After exposure of the NEG thin films to ambient air they become reactivated after a thermal treatment in an ultrahigh vacuum. In our case the films are heated up to ~250 degrees C for 2 h in a base pressure of ~10/sup -9/ Torr. (18 refs).

  17. Uniaxial crystal growth in thin film by utilizing supercooled state of mesogenic phthalocyanine

    Science.gov (United States)

    Fiderana Ramananarivo, Mihary; Higashi, Takuya; Ohmori, Masashi; Sudoh, Koichi; Fujii, Akihiko; Ozaki, Masanori

    2016-06-01

    A method of uniaxial crystal growth in wet-processed thin films of the mesogenic phthalocyanine 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH2) is proposed. It consists of applying geometrically linear thermal stimulation to a supercooled state of liquid crystalline C6PcH2. The thin film showed highly ordered molecular stacking structure and uniaxial alignment over a macroscopic scale. An explanation of the crystal growth mechanism is suggested by taking into account the temperature range of crystal growth and the hysteresis property of C6PcH2 in the phase transition.

  18. Experimental Investigation of Zinc Antimonide Thin Film Thermoelectric Element over Wide Range of Operating Conditions

    DEFF Research Database (Denmark)

    Hosseini, Seyed Mojtaba Mir; Rezaniakolaei, Alireza; Blichfeld, Anders Bank

    2017-01-01

    flows in plane with the thin film. At first, the effect of applying different temperatures at the hot side of the specimen is investigated to reach steady state in an open circuit analysis. Then, the study focuses on performance and stability analysis of the thermoelectric element operating under......Zinc antimonide compounds are among the most efficient thermoelectric (TE) materials with exceptional low thermal conductivity at moderate temperatures up to 350 °C. This study aims to evaluate the performance of a zinc antimonide thin film TE deposited on an insulating substrate, while the heat...

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

    Science.gov (United States)

    Hines, Jacqueline H. (Inventor)

    2015-01-01

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

  20. A comparative study of heterostructured CuO/CuWO4 nanowires and thin films

    Science.gov (United States)

    Polyakov, Boris; Kuzmin, Alexei; Vlassov, Sergei; Butanovs, Edgars; Zideluns, Janis; Butikova, Jelena; Kalendarev, Robert; Zubkins, Martins

    2017-12-01

    A comparative study of heterostructured CuO/CuWO4 core/shell nanowires and double-layer thin films was performed through X-ray diffraction, confocal micro-Raman spectroscopy and electron (SEM and TEM) microscopies. The heterostructures were produced using a two-step process, starting from a deposition of amorphous WO3 layer on top of CuO nanowires and thin films by reactive DC magnetron sputtering and followed by annealing at 650 °C in air. The second step induced a solid-state reaction between CuO and WO3 oxides through a thermal diffusion process, revealed by SEM-EDX analysis. Morphology evolution of core/shell nanowires and double-layer thin films upon heating was studied by electron (SEM and TEM) microscopies. A formation of CuWO4 phase was confirmed by X-ray diffraction and confocal micro-Raman spectroscopy.