WorldWideScience

Sample records for thermally treated films

  1. Structure and wettability property of the growth and nucleation surfaces of thermally treated freestanding CVD diamond films

    Science.gov (United States)

    Pei, Xiaoqiang; Cheng, Shaoheng; Ma, Yibo; Wu, Danfeng; Liu, Junsong; Wang, Qiliang; Yang, Yizhou; Li, Hongdong

    2015-08-01

    This paper reports the surface features and wettability properties of the (1 0 0)-textured freestanding chemical vapor deposited (CVD) diamond films after thermal exposure in air at high temperature. Thermal oxidation at proper conditions eliminates selectively nanodiamonds and non-diamond carbons in the films. The growth side of the films contains (1 0 0)-oriented micrometer-sized columns, while its nucleation side is formed of nano-sized tips. The examined wettability properties of the as-treated diamond films reveal a hydrophilicity and superhydrophilicity on the growth surface and nucleation surface, respectively, which is determined by oxygen termination and geometry structure of the surface. When the surface termination is hydrogenated, the wettability of nucleation side converted from superhydrophilicity to high hydrophobicity, while the hydrophilicity of the growth side does not change significantly. The findings open a possibility for realizing freestanding diamond films having not only novel surface structures but also multifunction applications, especially proposed on the selected growth side or nucleation side in one product.

  2. Improved electrical conduction properties in unintentionally-doped ZnO thin films treated by rapid thermal annealing

    International Nuclear Information System (INIS)

    Lee, Youngmin; Lee, Choeun; Shim, Eunhee; Jung, Eiwhan; Lee, Jinyong; Kim, Deukyoung; Lee, Sejoon; Fu, Dejun; Yoon, Hyungdo

    2011-01-01

    The effects of thermal treatments on the electrical conduction properties for the unintentionally doped ZnO thin films were investigated. Despite the decreased carrier density in the annealed ZnO thin films, the conductivity was increased because the contribution of the effective carrier mobility to the conductivity of the unintentionally-doped ZnO thin films is greater than that of the carrier density. The resistivity exponentially decreased with increasing RTA temperature, and this result was confirmed to come from the enhanced effective carrier-mobility, which originated from the increased crystallite size in the annealed ZnO thin films.

  3. Improved electrical conduction properties in unintentionally-doped ZnO thin films treated by rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngmin; Lee, Choeun; Shim, Eunhee; Jung, Eiwhan; Lee, Jinyong; Kim, Deukyoung; Lee, Sejoon [Dongguk University-Seoul, Seoul (Korea, Republic of); Fu, Dejun [Wuhan University, Wuhan (China); Yoon, Hyungdo [Korea Electronics Technology Institute, Seongnam (Korea, Republic of)

    2011-10-15

    The effects of thermal treatments on the electrical conduction properties for the unintentionally doped ZnO thin films were investigated. Despite the decreased carrier density in the annealed ZnO thin films, the conductivity was increased because the contribution of the effective carrier mobility to the conductivity of the unintentionally-doped ZnO thin films is greater than that of the carrier density. The resistivity exponentially decreased with increasing RTA temperature, and this result was confirmed to come from the enhanced effective carrier-mobility, which originated from the increased crystallite size in the annealed ZnO thin films.

  4. A comparative study of the physical properties of Sb2S3 thin films treated with N2 AC plasma and thermal annealing in N2

    International Nuclear Information System (INIS)

    Calixto-Rodriguez, M.; Martinez, H.; Pena, Y.; Flores, O.; Esparza-Ponce, H.E.; Sanchez-Juarez, A.; Campos-Alvarez, J.; Reyes, P.

    2010-01-01

    As-deposited antimony sulfide thin films prepared by chemical bath deposition were treated with nitrogen AC plasma and thermal annealing in nitrogen atmosphere. The as-deposited, plasma treated, and thermally annealed antimony sulfide thin films have been characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy, UV-vis spectroscopy, and electrical measurements. The results have shown that post-deposition treatments modify the crystalline structure, the morphology, and the optoelectronic properties of Sb 2 S 3 thin films. X-ray diffraction studies showed that the crystallinity of the films was improved in both cases. Atomic force microscopy studies showed that the change in the film morphology depends on the post-deposition treatment used. Optical emission spectroscopy (OES) analysis revealed the plasma etching on the surface of the film, this fact was corroborated by the energy dispersive X-ray spectroscopy analysis. The optical band gap of the films (E g ) decreased after post-deposition treatments (from 2.36 to 1.75 eV) due to the improvement in the grain sizes. The electrical resistivity of the Sb 2 S 3 thin films decreased from 10 8 to 10 6 Ω-cm after plasma treatments.

  5. Atomic force microscopy study of TiO2 sol-gel films thermally treated under NH3 atmosphere

    International Nuclear Information System (INIS)

    Trapalis, C.; Todorova, N.; Anastasescu, M.; Anastasescu, C.; Stoica, M.; Gartner, M.; Zaharescu, M.; Stoica, T.

    2009-01-01

    Multilayered TiO 2 films were obtained by sol-gel and dipping deposition on quartz substrate followed by thermal treatment under NH 3 atmosphere. In an attempt to understand the close relationship between microstructural characteristics and the synthesis parameters, a systematic research of the structure and the morphology of NH 3 modified TiO 2 sol-gel films by XRD and Atomic Force Microscopy is reported. The surface morphology has been evaluated in terms of grains size, fractal dimension and surface roughness. For each surface, it was found a self-similar behavior (with mean fractal dimension in the range of 2.67-3.00) related to an optimum morphology favorable to maintain a nano-size distribution of the grains. The root mean square (RMS) roughness of the samples was found to be in the range of 0.72-6.02 nm.

  6. A comparative study of the physical properties of Sb{sub 2}S{sub 3} thin films treated with N{sub 2} AC plasma and thermal annealing in N{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Calixto-Rodriguez, M., E-mail: manuela@fis.unam.mx [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210, Cuernavaca, Morelos (Mexico); Martinez, H. [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210, Cuernavaca, Morelos (Mexico); Pena, Y. [Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Pedro de Alba s/n, Cd. Universitaria, 66451, San Nicolas de los Garza, Nuevo Leon (Mexico); Flores, O. [Instituto de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62210, Cuernavaca, Morelos (Mexico); Esparza-Ponce, H.E. [Centro de Investigacion en Materiales Avanzados S.C., Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes 120, Complejo Industrial Chihuahua, Chihuahua, Chihuahua 31109 (Mexico); Sanchez-Juarez, A.; Campos-Alvarez, J. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Privada Xochicalco s/n, Col. Centro, 62580, Temixco, Morelos (Mexico); Reyes, P. [Facultad de Ciencias, Departamento de Fisica, Universidad Autonoma del Estado de Mexico, Instituto Literario 100, Col. Centro, 50000, Toluca, Estado de Mexico (Mexico)

    2010-02-01

    As-deposited antimony sulfide thin films prepared by chemical bath deposition were treated with nitrogen AC plasma and thermal annealing in nitrogen atmosphere. The as-deposited, plasma treated, and thermally annealed antimony sulfide thin films have been characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy, UV-vis spectroscopy, and electrical measurements. The results have shown that post-deposition treatments modify the crystalline structure, the morphology, and the optoelectronic properties of Sb{sub 2}S{sub 3} thin films. X-ray diffraction studies showed that the crystallinity of the films was improved in both cases. Atomic force microscopy studies showed that the change in the film morphology depends on the post-deposition treatment used. Optical emission spectroscopy (OES) analysis revealed the plasma etching on the surface of the film, this fact was corroborated by the energy dispersive X-ray spectroscopy analysis. The optical band gap of the films (E{sub g}) decreased after post-deposition treatments (from 2.36 to 1.75 eV) due to the improvement in the grain sizes. The electrical resistivity of the Sb{sub 2}S{sub 3} thin films decreased from 10{sup 8} to 10{sup 6} {Omega}-cm after plasma treatments.

  7. Influence of the substrate and nitrogen amount on the microstructural and optical properties of thin r.f.-sputtered ZnO films treated by rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Nicolescu, Madalina [Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Anastasescu, Mihai, E-mail: manastasescu@icf.ro [Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Preda, S.; Stroescu, H.; Stoica, M. [Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania); Teodorescu, V.S. [National Institute of Material Physics, 105 bis Atomistilor Street, 077125 Bucharest-Magurele (Romania); Aperathitis, E.; Kampylafka, V. [FORTH-IESL, Crete (Greece); Modreanu, M. [Tyndall National Institute, University College Cork, Cork (Ireland); Zaharescu, M.; Gartner, M. [Institute of Physical Chemistry, Romanian Academy, Spl. Independentei 202, 060021 Bucharest (Romania)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer ZnO:N films are crystallized in hexagonal wurtzite phase (XRD), (0 0 2) oriented. Black-Right-Pointing-Pointer The presence of the Nitrogen in the RTA films is confirmed by EDX and XPS. Black-Right-Pointing-Pointer All ZnO:N films are highly transparent (over 80%) in VIS to NIR spectral range. Black-Right-Pointing-Pointer The frequency of the phonon modes, E{sub 1}(TO) and A{sub 1}(LO), were obtained by IRSE. - Abstract: N-doped ZnO (ZnO:N) thin films, intended to be used as one of the layers in solar cell applications were deposited by r.f. sputtering, using ZnN target (99.9% purity), on silicon and fused silica substrates. In the gas flow composition, Ar was kept constant (50%) and the O{sub 2}/N{sub 2} ratio was varied as: 40%/10%, 25%/25% and 10%/40%. After deposition, rapid thermal annealing (RTA) at 400 and 550 Degree-Sign C for 1 min in N{sub 2} ambient has been performed. The RTA impact on the optical and microstructural properties of ZnO:N thin films have been investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) coupled with selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDX), UV-vis-NIR spectroscopy, UV-vis-NIR spectroscopic ellipsometry (SE) and infrared ellipsometry (IR-SE). The as-deposited (ad) ZnO:N films are polycrystalline with preferentially oriented columnar crystals. After RTA we found ZnO:N films with improved crystallinity and fewer boundary defects. We report optical constants of ZnO:N from UV to IR spectral range as well as the infrared active phononic modes.

  8. Thermal conductivity of oriented polymer films

    NARCIS (Netherlands)

    Nysten, B.; Gonry, P.; Issi, J.P.; Govaert, L.E.; Lemstra, P.J.; Tong, T.W.

    1994-01-01

    The effect of stretching on the thermal cond. of polyethylene (PE) films is presented and compared to results obtained previously for oriented polyacetylene films and PE fibers. As expected, the longitudinal thermal cond. increases with the stretching level and thermal cond. values comparable to

  9. Thermal conductivity of sputtered amorphous Ge films

    International Nuclear Information System (INIS)

    Zhan, Tianzhuo; Xu, Yibin; Goto, Masahiro; Tanaka, Yoshihisa; Kato, Ryozo; Sasaki, Michiko; Kagawa, Yutaka

    2014-01-01

    We measured the thermal conductivity of amorphous Ge films prepared by magnetron sputtering. The thermal conductivity was significantly higher than the value predicted by the minimum thermal conductivity model and increased with deposition temperature. We found that variations in sound velocity and Ge film density were not the main factors in the high thermal conductivity. Fast Fourier transform patterns of transmission electron micrographs revealed that short-range order in the Ge films was responsible for their high thermal conductivity. The results provide experimental evidences to understand the underlying nature of the variation of phonon mean free path in amorphous solids

  10. Thermal conductivity of nanoscale thin nickel films

    Institute of Scientific and Technical Information of China (English)

    YUAN Shiping; JIANG Peixue

    2005-01-01

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

  11. 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.

  12. Thermal propagation and stability in superconducting films

    International Nuclear Information System (INIS)

    Gray, K.E.; Kampwirth, R.T.; Zasadzinski, J.F.; Ducharme, S.P.

    1983-01-01

    Thermal propagation and stable hot spots (normal domains) are studied in various high Tsub(c) superconducting films (Nb 3 Sn, Nb, NbN and Nb 3 Ge). A new energy balance is shown to give reasonable quantitative agreement of the dependence of the propagation velocity on the length of short normal domains. The steady state (zero velocity) measurements indicate the existence of two distinct situations for films on high thermal conductivity (sapphire) substrates. For low power per unit area the film and substrate have the same temperature, and the thermal properties of the substrate dominate. However, for higher power densities in short hot spots, the coupling is relatively weak and the thermal properties of the film alone are important. Here a connection is made between the critical current stability of superconducting films and a critical hot spot size for thermal propagation. As a result efficient heat removal is shown to dominate the stabilisation of superconducting films. The strong and weak coupling situations also lead to modifications of the models for propagation velocities on sapphire substrates. Self-healing of hot spots and other phenomena in superconducting film are explained. The potential use of the thermal propagation model in applications of superconductors, especially switches is discussed. (author)

  13. Thin Film Photovoltaic/Thermal Solar Panels

    Institute of Scientific and Technical Information of China (English)

    David JOHNSTON

    2008-01-01

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

  14. Thermal Transport in Diamond Films for Electronics Thermal Management

    Science.gov (United States)

    2018-03-01

    AFRL-RY-WP-TR-2017-0219 THERMAL TRANSPORT IN DIAMOND FILMS FOR ELECTRONICS THERMAL MANAGEMENT Samuel Graham Georgia Institute of Technology MARCH... ELECTRONICS THERMAL MANAGEMENT 5a. CONTRACT NUMBER FA8650-15-C-7517 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 61101E 6. AUTHOR(S) Samuel...seeded sample (NRL 010516, Die A5). The NCD membrane and Al layer thicknesses, tNCD, were measured via transmission electron microscopy (TEM). The

  15. Adsorption properties of thermally sputtered calcein film

    Science.gov (United States)

    Kruglenko, I.; Burlachenko, J.; Kravchenko, S.; Savchenko, A.; Slabkovska, M.; Shirshov, Yu.

    2014-05-01

    High humidity environments are often found in such areas as biotechnology, food chemistry, plant physiology etc. The controlling of parameters of such ambiences is vitally important. Thermally deposited calcein films have extremely high adsorptivity at exposure to water vapor of high concentration. This feature makes calcein a promising material for humidity sensing applications. The aim of this work is to explain high sensitivity and selectivity of calcein film to high humidity. Quartz crystal microbalance sensor, AFM and ellipsometry were used for calcein film characterization and adsorption properties investigation. The proposed model takes into account both the molecular properties of calcein (the presence of several functional groups capable of forming hydrogen bonds, and their arrangement) and the features of structure of thermally deposited calcein film (film restructuring due to the switching of bonds "calcein-calcein" to "calcein-water" in the course of water adsorption).

  16. Thermal Analysis of Sintered Silver Nanoparticles Film

    Directory of Open Access Journals (Sweden)

    M. Keikhaie

    2014-07-01

    Full Text Available Thin bonded films have many applications in antireflection and reflection coating, insulating and conducting films and semiconductor industries. Thermal conductivity is one of the most important parameter for power packaging since the thermal resistance of the interconnections is directly related to the heat removal capability and thermal management of the power package. The defects in materials play very important role on the effective thermal conductivity. In this paper, finite element method (FEM was utilized to simulate the effect of pores on the effective thermal conductivity of sintered silver nanoparticles film. The simulation results indicate that the effective thermal conductivity of film is different at different directions and would be enhanced when the pore angle is 90. The simulation results will help us to further understand the heat transfer process across highly porous structures and will provide us a powerful guide to design coating with high thermal insulation or conductor property. Because of there is no similar experimental data for this simulation results, this paper is a comparative work among three different models.

  17. Thermal conductivities of thin, sputtered optical films

    International Nuclear Information System (INIS)

    Henager, C.H. Jr.; Pawlewicz, W.T.

    1991-05-01

    The normal component of the thin film thermal conductivity has been measured for the first time for several advanced sputtered optical materials. Included are data for single layers of boron nitride (BN), aluminum nitride (AIN), silicon aluminum nitride (Si-Al-N), silicon aluminum oxynitride (Si-Al-O-N), silicon carbide (SiC), and for dielectric-enhanced metal reflectors of the form Al(SiO 2 /Si 3 N 4 ) n and Al(Al 2 O 3 /AIN) n . Sputtered films of more conventional materials like SiO 2 , Al 2 O 3 , Ta 2 O 5 , Ti, and Si have also been measured. The data show that thin film thermal conductivities are typically 10 to 100 times lower than conductivities for the same materials in bulk form. Structural disorder in the amorphous or very fine-grained films appears to account for most of the conductivity difference. Conclusive evidence for a film/substrate interface contribution is presented

  18. Thermally-treated Pt-coated silicon AFM tips for wear resistance in ferroelectric data storage

    International Nuclear Information System (INIS)

    Bhushan, Bharat; Palacio, Manuel; Kwak, Kwang Joo

    2008-01-01

    In ferroelectric data storage, a conductive atomic force microscopy (AFM) probe with a noble metal coating is placed in contact with a lead zirconate titanate (PZT) film. The understanding and improvement of probe tip wear, particularly at high velocities, is needed for high data rate recording. A commercial Pt-coated silicon AFM probe was thermally treated in order to form platinum silicide at the near-surface. Nanoindentation, nanoscratch and wear experiments were performed to evaluate the mechanical properties and wear performance at high velocities. The thermally treated tip exhibited lower wear than the untreated tip. The tip wear mechanism is adhesive and abrasive wear with some evidence of impact wear. The enhancement in mechanical properties and wear resistance in the thermally treated film is attributed to silicide formation in the near-surface. Auger electron spectroscopy and electrical resistivity measurements confirm the formation of platinum silicide. This study advances the understanding of thin film nanoscale surface interactions

  19. Cytocompatibility of Plasma and Thermally Treated Biopolymers

    Directory of Open Access Journals (Sweden)

    Petr Slepička

    2013-01-01

    Full Text Available This paper is focused on the surface characterization of plasma and consequently thermally treated biocompatible polymers. PLLA (poly(L-lactide acid and PMP (poly-4-methyl-1-pentene are studied. The influence of Ar plasma treatment on the surface polarity of substrate measured immediately after treatment and during the polymer surface aging is studied. Surface roughness, morphology, wettability, and surface chemistry were determined. Plasma treatment leads to significant changes in PLLA surface morphology and chemistry, with the PMP being slightly affected. The higher resistance to plasma fluence results in smaller ablation of PMP than that of PLLA. The plasma treatment improves cell adhesion and proliferation on the PMP. Plasma treatment of PLLA influences mostly the homogeneity of adhered and proliferated VSMC.

  20. Thermal diffusivity of diamond films using a laser pulse technique

    International Nuclear Information System (INIS)

    Albin, S.; Winfree, W.P.; Crews, B.S.

    1990-01-01

    Polycrystalline diamond films were deposited using a microwave plasma-enhanced chemical vapor deposition process. A laser pulse technique was developed to measure the thermal diffusivity of diamond films deposited on a silicon substrate. The effective thermal diffusivity of a diamond film on silicon was measured by observing the phase and amplitude of the cyclic thermal waves generated by laser pulses. An analytical model is presented to calculate the effective inplane (face-parallel) diffusivity of a two-layer system. The model is used to reduce the effective thermal diffusivity of the diamond/silicon sample to a value for the thermal diffusivity and conductivity of the diamond film

  1. Thermal decomposition of titanium deuteride thin films

    International Nuclear Information System (INIS)

    Malinowski, M.E.

    1983-01-01

    The thermal desorption spectra of deuterium from essentially clean titanium deuteride thin films were measured by ramp heating the films in vacuum; the film thicknesses ranged from 20 to 220 nm and the ramp rates varied from 0.5 to about 3 0 C s - 1 . Each desorption spectrum consisted of a low nearly constant rate at low temperatures followed by a highly peaked rate at higher temperatures. The cleanliness and thinness of the films permitted a description of desorption rates in terms of a simple phenomenological model based on detailed balancing in which the low temperature pressure-composition characteristics of the two-phase (α-(α+#betta#)-#betta#) region of the Ti-D system were used as input data. At temperatures below 340 0 C the model predictions were in excellent agreement with the experimentally measured desorption spectra. Interpretations of the spectra in terms of 'decomposition trajectories'' are possible using this model, and this approach is also used to explain deviations of the spectra from the model at temperatures of 340 0 C and above. (Auth.)

  2. Stripe domains and magnetoresistance in thermally deposited nickel films

    International Nuclear Information System (INIS)

    Sparks, P.D.; Stern, N.P.; Snowden, D.S.; Kappus, B.A.; Checkelsky, J.G.; Harberger, S.S.; Fusello, A.M.; Eckert, J.C.

    2004-01-01

    We report a study of the domain structure and magnetoresistance of thermally deposited nickel films. For films thicker than 17 nm, we observe striped domains with period varying with film thickness as a power law with exponent 0.21±0.02 up to 120 nm thickness. There is a negative magnetoresistance for fields out of the plane

  3. Stripe domains and magnetoresistance in thermally deposited nickel films

    Science.gov (United States)

    Sparks, P. D.; Stern, N. P.; Snowden, D. S.; Kappus, B. A.; Checkelsky, J. G.; Harberger, S. S.; Fusello, A. M.; Eckert, J. C.

    2004-05-01

    We report a study of the domain structure and magnetoresistance of thermally deposited nickel films. For films thicker than 17nm, we observe striped domains with period varying with film thickness as a power law with exponent 0.21+/-0.02 up to 120nm thickness. There is a negative magnetoresistance for fields out of the plane.

  4. Stripe domains and magnetoresistance in thermally deposited nickel films

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, P.D. E-mail: sparks@hmc.edu; Stern, N.P.; Snowden, D.S.; Kappus, B.A.; Checkelsky, J.G.; Harberger, S.S.; Fusello, A.M.; Eckert, J.C

    2004-05-01

    We report a study of the domain structure and magnetoresistance of thermally deposited nickel films. For films thicker than 17 nm, we observe striped domains with period varying with film thickness as a power law with exponent 0.21{+-}0.02 up to 120 nm thickness. There is a negative magnetoresistance for fields out of the plane.

  5. 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

  6. 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.

  7. Treating Fibrous Insulation to Reduce Thermal Conductivity

    Science.gov (United States)

    Zinn, Alfred; Tarkanian, Ryan

    2009-01-01

    A chemical treatment reduces the convective and radiative contributions to the effective thermal conductivity of porous fibrous thermal-insulation tile. The net effect of the treatment is to coat the surfaces of fibers with a mixture of transition-metal oxides (TMOs) without filling the pores. The TMO coats reduce the cross-sectional areas available for convection while absorbing and scattering thermal radiation in the pores, thereby rendering the tile largely opaque to thermal radiation. The treatment involves a sol-gel process: A solution containing a mixture of transition-metal-oxide-precursor salts plus a gelling agent (e.g., tetraethylorthosilicate) is partially cured, then, before it visibly gels, is used to impregnate the tile. The solution in the tile is gelled, then dried, and then the tile is fired to convert the precursor salts to the desired mixed TMO phases. The amounts of the various TMOs ultimately incorporated into the tile can be tailored via the concentrations of salts in the solution, and the impregnation depth can be tailored via the viscosity of the solution and/or the volume of the solution relative to that of the tile. The amounts of the TMOs determine the absorption and scattering spectra.

  8. Air-Lubricated Thermal Processor For Dry Silver Film

    Science.gov (United States)

    Siryj, B. W.

    1980-09-01

    Since dry silver film is processed by heat, it may be viewed on a light table only seconds after exposure. On the other hand, wet films require both bulky chemicals and substantial time before an image can be analyzed. Processing of dry silver film, although simple in concept, is not so simple when reduced to practice. The main concern is the effect of film temperature gradients on uniformity of optical film density. RCA has developed two thermal processors, different in implementation but based on the same philosophy. Pressurized air is directed to both sides of the film to support the film and to conduct the heat to the film. Porous graphite is used as the medium through which heat and air are introduced. The initial thermal processor was designed to process 9.5-inch-wide film moving at speeds ranging from 0.0034 to 0.008 inch per second. The processor configuration was curved to match the plane generated by the laser recording beam. The second thermal processor was configured to process 5-inch-wide film moving at a continuously variable rate ranging from 0.15 to 3.5 inches per second. Due to field flattening optics used in this laser recorder, the required film processing area was plane. In addition, this processor was sectioned in the direction of film motion, giving the processor the capability of varying both temperature and effective processing area.

  9. Films of chitin, chitosan and cellulose obtained from aqueous suspension treated by irradiation of high intensity ultrasound

    International Nuclear Information System (INIS)

    Almeida, Erika V.R.; Mariano, Mario S.; Campana-Filho, Sergio P.

    2011-01-01

    Films of chitin, chitin/chitosan and chitin/sisal cellulose were obtained by casting their aqueous suspensions previously treated with irradiation of high intensity ultrasound. The films were characterized for surface morphology by scanning electron microscopy and it is possible notice that the films containing chitosan are much more homogeneous. The thermal behavior of the films was evaluated by dynamic mechanical thermal analysis, differential scanning calorimetry, and thermogravimetric analysis and revealing similarity in comparison with the thermal behavior of polysaccharide isolated. The tensile strength was determined and the film containing chitosan showed the best result when compared to other films. The crystallinity index of the films analyzed by X-ray diffraction showed that the films are amorphous material. The analysis by infrared spectroscopy showed that treatment of aqueous suspensions of polysaccharides with irradiation of high intensity ultrasound did not change the chemical structure of polymers. The crystallinity index was determined by X-ray diffraction, revealing that the films are amorphous materials. The results of this study indicate the possibility of processing of chitin, chitosan and cellulose, polysaccharides whose solubilities are limited to a few solvent systems, by treating their aqueous suspensions with high intensity ultrasound. (author)

  10. Thermal annealing of amorphous Ti-Si-O thin films

    OpenAIRE

    Hodroj , Abbas; Chaix-Pluchery , Odette; Audier , Marc; Gottlieb , Ulrich; Deschanvres , Jean-Luc

    2008-01-01

    International audience; Ti-Si-O thin films were deposited using an aerosol chemical vapor deposition process at atmospheric pressure. The film structure and microstructure were analysed using several techniques before and after thermal annealing. Diffraction results indicate that the films remain X-ray amorphous after annealing whereas Fourier transform infrared spectroscopy gives evidence of a phase segregation between amorphous SiO2 and well crystallized anatase TiO2. Crystallization of ana...

  11. Plastic response of thin films due to thermal cycling

    NARCIS (Netherlands)

    Nicola, L.; van der Giessen, E.; Needleman, A.; Ahzi, S; Cherkaoui, M; Khaleel, MA; Zbib, HM; Zikry, MA; Lamatina, B

    2004-01-01

    Discrete dislocation simulations of thin films on semi-infinite substrates under cyclic thermal loading are presented. The thin film is modelled as a two-dimensional single crystal under plane strain conditions. Dislocations of edge character can be generated from initially present sources and glide

  12. 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)

  13. Electrochemical and Thermal Studies of Prepared Conducting Chitosan Biopolymer Film

    International Nuclear Information System (INIS)

    Hlaing Hlaing Oo; Kyaw Naing; Kyaw Myo Naing; Tin Tin Aye; Nyunt Wynn

    2005-09-01

    In this paper, chitosan based conducting bipolymer films were prepared by casting and solvent evaporating technique. All prepared chitosan films were of pale yellow colour, transparent, and smooth. Sulphuric acid was chosen as the cross-linking agent. It enhanced conduction pathway in cross-linked chitosan films. Mechanical properties, solid-state, and thermal behavior of prepared chitosan fimls were studied by means of a material testing machine, powder X-ray diffractometry (XRD), thermogravimetric analysis (TG-DTG), and differential scanning calorimetry (DSC). By the XRD diffraction pattern, high molecular weight of chitosan product indicates the semi-crystalline nature, but the prepared chitosan film and doped chitosan film indicate significantly lower in crystallinity prove which of the amorphous characteristics. In addition, DSC thermogram of pure chitosan film exhibited exothermic peak around at 300 C, indicating polymer decomposition of chitosan molecules in chitosan films. Furthermore, these DSC thermograms clearly showed that while pure chitosan film display exothermal decomposition, the doped chitosan films mainly endothermic characteristics. The ionic conductivity of doped chitosan films were in the order of 10 to 10 S cm , which is in the range of semi-conductor. These results showed that cross-linked chitoson films may be used as polymer electrolyte film to fabricate solid state electrochemical cells

  14. Thermal stability of ultrasoft Fe-Zr-N films

    NARCIS (Netherlands)

    Chechenin, NG; van Veen, A; Schut, H; Chezan, AR; Boerma, D; Vystavel, T; De Hosson, JTM

    2003-01-01

    The thermal stability of nanocrystalline ultrasoft magnetic (Fe98Zr2)(1-x)N-x films with x = 0.10-0.25 was studied using thermal desorption spectrometry, positron beam analysis and high resolution transmission electron microscopy. The results demonstrate that grain growth during the heat treatment

  15. Properties of Al- and Ga-doped thin zinc oxide films treated with UV laser radiation

    Science.gov (United States)

    Al-Asedy, Hayder J.; Al-Khafaji, Shuruq A.; Bakhtiar, Hazri; Bidin, Noriah

    2018-03-01

    This paper reports the Nd:YAG laser irradiation treated modified properties of aluminum (Al) and gallium (Ga) co-doped zinc oxide (ZnO) (AGZO) films prepared on Si-substrate via combined sol-gel and spin-coating method. The impact of varying laser energy (150-200 mJ) on the structure, morphology, electrical and optical properties of such AGZO films were determined. Laser-treated samples were characterized using various analytical tools. Present techniques could achieve a high-quality polycrystalline films compared with those produced via conventional high temperature processing. AGZO films irradiated with third harmonics UV radiation (355 nm) from Nd:YAG laser source revealed very low resistivity of 4.02 × 10- 3 Ω cm. The structural properties grain size was calculated firm the X-ray diffraction spectra using the Scherrer equation that increased from 12.7 to 22.5 nm as the annealing laser energy increased from (150-200) mJ. The differences in crystallinity and orientation are explained in terms of the thermal effect caused by laser irradiation. (FESEM) images have been demonstrated that Nd:YAG laser annealing can significantly improve the crystallinity level, densification, and surface flatness of sol-gel derived AGZO thin films that occurred as a result of laser processing. Synthesized AGZO films displayed favorable growth orientation along (101) lattice direction. AGZO films with energy band gap of 3.37-3.41 eV were obtained. Results on the crystallinity, surface morphology, roughness, bonding vibration, absorption, photoluminescence, and resistivity of the laser-irradiated films were analyzed and discussed.

  16. Leaching of arsenic, copper and chromium from thermally treated soil.

    Science.gov (United States)

    Kumpiene, Jurate; Nordmark, Désirée; Hamberg, Roger; Carabante, Ivan; Simanavičienė, Rūta; Aksamitauskas, Vladislovas Česlovas

    2016-12-01

    Thermal treatment, if properly performed, is an effective way of destroying organic compounds in contaminated soil, while impact on co-present inorganic contaminants varies depending on the element. Leaching of trace elements in thermally treated soil can be altered by co-combusting different types of materials. This study aimed at assessing changes in mobility of As, Cr and Cu in thermally treated soil as affected by addition of industrial by-products prior to soil combustion. Contaminated soil was mixed with either waste of gypsum boards, a steel processing residue (Fe 3 O 4 ), fly ash from wood and coal combustion or a steel abrasive (96.5% Fe 0 ). The mixes and unamended soil were thermally treated at 800 °C and divided into a fine fraction 0.125 mm to simulate particle separation occurring in thermal treatment plants. The impact of the treatment on element behaviour was assessed by a batch leaching test, X-ray absorption spectroscopy and dispersive X-ray spectrometry. The results suggest that thermal treatment is highly unfavourable for As contaminated soils as it increased both the As leaching in the fine particle size fraction and the mass of the fines (up to 92%). Soil amendment with Fe-containing compounds prior to the thermal treatment reduced As leaching to the levels acceptable for hazardous waste landfills, but only in the coarse fraction, which does not justify the usefulness of such treatment. Among the amendments used, gypsum most effectively reduced leaching of Cr and Cu in thermally treated soil and could be recommended for soils that do not contain As. Fly ash was the least effective amendment as it increased leaching of both Cr and As in majority of samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Spin current relaxation time in thermally evaporated pentacene films

    OpenAIRE

    Tani, Yasuo; Kondo, Takuya; Teki, Yoshio; Shikoh, Eiji

    2017-01-01

    The spin current relaxation time [tau] in thermally evaporated pentacene films was evaluated with the spin-pump-induced spin transport properties and the charge current transport properties in pentacene films. Under an assumption of a diffusive transport of the spin current in pentacene films, the zero-field mobility and the diffusion constant of holes in pentacene films were experimentally obtained to be ~8.0x10^-7 m^2/Vs and ~2.0x10^-8 m^2/s, respectively. Using those values and the previou...

  18. Effects of Thermal Annealing Conditions on Cupric Oxide Thin Film

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo Seon; Oh, Hee-bong; Ryu, Hyukhyun [Inje University, Gimhae (Korea, Republic of); Lee, Won-Jae [Dong-Eui University, Busan (Korea, Republic of)

    2015-07-15

    In this study, cupric oxide (CuO) thin films were grown on fluorine doped tin oxide(FTO) substrate by using spin coating method. We investigated the effects of thermal annealing temperature and thermal annealing duration on the morphological, structural, optical and photoelectrochemical properties of the CuO film. From the results, we could find that the morphologies, grain sizes, crystallinity and photoelectrochemical properties were dependent on the annealing conditions. As a result, the maximum photocurrent density of -1.47 mA/cm{sup 2} (vs. SCE) was obtained from the sample with the thermal annealing conditions of 500 ℃ and 40 min.

  19. Thermal conductivity of a film of single walled carbon nanotubes measured with infrared thermal imager

    Science.gov (United States)

    Feng, Ya; Inoue, Taiki; Xiang, Rong; Chiashi, Shohei; Maruyama, Shigeo

    Heat dissipation has restricted the modern miniaturization trend with the development of electronic devices. Theoretically proven to be with high axial thermal conductivity, single walled carbon nanotubes (SWNT) have long been expected to cool down the nanoscale world. Even though the tube-tube contact resistance limits the capability of heat transfer of the bulk film, the high intrinsic thermal conductivity of SWNT still glorify the application of films of SWNT network as a thermal interface material. In this work, we proposed a new method to straightly measure the thermal conductivity of SWNT film. We bridged two cantilevered Si thin plate with SWNT film, and kept a steady state heat flow in between. With the infrared camera to record the temperature distribution, the Si plates with known thermal conductivity can work as a reference to calculate the heat flux going through the SWNT film. Further, the thermal conductivity of the SWNT film can be obtained through Fourier's law after deducting the effect of thermal radiation. The sizes of the structure, the heating temperature, the vacuum degree and other crucial impact factors are carefully considered and analyzed. The author Y. F. was supported through the Advanced Integration Science Innovation Education and Research Consortium Program by the Ministry of Education, Culture, Sport, Science and Technology.

  20. Surface properties of thermally treated composite wood panels

    Science.gov (United States)

    Croitoru, Catalin; Spirchez, Cosmin; Lunguleasa, Aurel; Cristea, Daniel; Roata, Ionut Claudiu; Pop, Mihai Alin; Bedo, Tibor; Stanciu, Elena Manuela; Pascu, Alexandru

    2018-04-01

    Composite finger-jointed spruce and oak wood panels have been thermally treated under standard pressure and oxygen content conditions at two different temperatures, 180 °C and respectively 200 °C for short time periods (3 and 5 h). Due to the thermally-aided chemical restructuration of the wood components, a decrease in water uptake and volumetric swelling values with up to 45% for spruce and 35% for oak have been registered, comparing to the reference samples. In relation to water resistance, a 15% increase of the dispersive component of the surface energy has been registered for the thermal-treated spruce panels, which impedes water spreading on the surface. The thermal-treated wood presents superior resistance to accelerated UV exposure and subsequently, with up to 10% higher Brinell hardness values than reference wood. The proposed thermal treatment improves the durability of the finger-jointed wood through a more economically and environmental friendly method than traditional impregnation, with minimal degradative impact on the structural components of wood.

  1. Adhesion and thermal stability enhancement of IZO films by adding a primer layer on polycarbonate substrate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuan; Zhang, Xiaofeng; Yan, Yue; Zhong, Yanli; Li, Lei; Zhang, Guanli [Beijing Institute of Aeronautical Materials (BIAM), Haidian District, Beijing, 100095 (China)

    2015-04-01

    A silicone-based primer layer was developed to improve the adhesion and thermal stability of amorphous transparent indium zinc oxide (IZO) films on polycarbonate (PC). The IZO films deposited by direct current magnetron sputtering at room temperature on primer-treated and untreated PCs were evaluated ex situ in terms of surface morphology, adhesion, optical, and electrical properties during annealing at 120 C in air. Nano-scratch tests indicated the adhesion of IZO films on primer-treated substrates was superior to that on untreated PCs. This superior adhesion can be attributed to the strong Si-O-Si inorganic bonds abundant in the primer layer and better matches of the primer layer in the terms of thermal expansion to the IZO. Moreover, the electrical resistivity of IZO films prepared on primer-treated PCs remained stable during the annealing treatment, whereas those of IZO films on untreated PCs presented a continuously increasing trend, which was attributed to the decrease in carrier concentration that resulted from oxygen adsorption. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Thermal evolution of CaO-doped HfO{sub 2} films and powders

    Energy Technology Data Exchange (ETDEWEB)

    Barolin, S A; Sanctis, O A de [Lab. Materiales Ceramicos, FCEIyA, Universidad Nacional de Rosario, IFIR-CONICET (Argentina); Caracoche, M C; Martinez, J A; Taylor, M A; Pasquevich, A F [Departamento de Fisica, FCE, Universidad Nacional de La Plata, IFLP-CONICET (Argentina); Rivas, P C, E-mail: oski@fceia.unr.edu.a [Facultad de Ciencias Agronomicas y Forestales, Universidad Nacional de La Plata, IFLP (Argentina)

    2009-05-01

    Solid solutions of ZrO2 and HfO2 are potential electrolyte materials for intermediate-temperature SOFC because both are oxygen-ion conductors. The main challenge for these compounds is to reduce the relatively high value of the activation energies vacancies diffusion, which is influenced by several factors. In this work the thermal evolution of CaO-HfO{sub 2} materials have been investigated. (CaO)y-Hf(1-y)O(2-y) (y = 0.06, 0.14 y 0.2) coatings and powders were synthesized by chemical solution deposition (CSD). Films were deposited onto alumina substrates by Dip Coating technique, the burning of organic waste was carried out at 500 deg. C under normal atmosphere and then the films were thermally treated at intervals of temperature rising to a maximum temperature of 1250 deg. C. By means Glazing Incidence X-ray Diffraction (rho-2theta configuration) the phases were studied in the annealed films. On the other hand, the thermal evolution and crystallization process of powders were analyzed in-situ by HT-XRD. The phenomena crystallization occurred in films and powders were analyzed. The activation energies of diffusion of oxygen vacancies of HfO2-14 mole% CaO and HfO2-20 mole% CaO films were measured from the thermal evolution of the relaxation constant measured by Perturbed Angular Correlation Technique.

  3. Ion assisted deposition of thermally evaporated Ag and Al films

    International Nuclear Information System (INIS)

    Hwangbo, C.K.; Lingg, L.J.; Lehan, J.P.; Macleod, H.A.; Makous, J.L.; Kim, S.Y.; University of Arizona, Physics Department, Tucson, Arizona 85721; Aju University, Physics Department, Suwon, Korea)

    1989-01-01

    Optical, electrical, and microstructural effects of Ar ion bombardment and Ar incorporation on thermally evaporated Ag and Al thin films are investigated. The results show that as the momentum supplied to the growing films by the bombarding ions per arriving metal atom increases, the refractive index at 632.8 nm increases and the extinction coefficient decreases, lattice spacing expands, grain size decreases, electrical resistivity increases, and trapped Ar increases slightly. In Ag films, stress reverses from tensile to compressive and in Al films compressive stress increases. In the Al films the change in optical constants can be explained by the variation in void volume. The reversal of stress from tensile to compressive in Ag films requires a threshold level of momentum. The increase in electrical resistivity is related to the decrease in grain size and increase in trapped Ar in both types of film. Many of these properties correlate well with the momentum transferred, suggesting that the momentum is an important physical parameter in describing the influence of ion beam on growing thin films and determining the characteristics of thin metal films prepared by ion assisted deposition

  4. Patterned magnetite films prepared via soft lithography and thermal decomposition

    International Nuclear Information System (INIS)

    An Lijuan; Li, Zhaoqiang; Li Wei; Nie Yaru; Chen Zhimin; Wang Yanping; Yang Bai

    2006-01-01

    A method for the fabrication of patterned magnetite (Fe 3 O 4 ) films is presented. We first prepared an ordered 2D array of Fe(acac) 3 through a selective deposition technique on patterned self-assembled monolayers. Using thermal decomposition at elevated temperature (300 o C), we transformed the patterned Fe(acac) 3 into patterned Fe 3 O 4 films in a short reaction time. These patterned films have been confirmed by using optical photographs, field emission scanning electron microscopy and atomic force microscopy

  5. Properties of Nanostructure Bismuth Telluride Thin Films Using Thermal Evaporation

    Directory of Open Access Journals (Sweden)

    Swati Arora

    2017-01-01

    Full Text Available Bismuth telluride has high thermoelectric performance at room temperature; in present work, various nanostructure thin films of bismuth telluride were fabricated on silicon substrates at room temperature using thermal evaporation method. Tellurium (Te and bismuth (Bi were deposited on silicon substrate in different ratio of thickness. These films were annealed at 50°C and 100°C. After heat treatment, the thin films attained the semiconductor nature. Samples were studied by X-ray diffraction (XRD and scanning electron microscopy (SEM to show granular growth.

  6. Thermal cycling characteristics of plasma synthesized mullite films

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, O.R.; Hou, P.Y.; Brown, I.G. [Lawrence Berkeley National Lab., CA (United States)

    1997-12-01

    The authors have developed a plasma-based technique for the synthesis of mullite and mullite-like films on silicon carbide substrate material. The method, which they refer to as MePIIID (for Metal Plasma Immersion Ion Implantation and Deposition), uses two vacuum arc plasma sources and simultaneous pulse biasing of the substrate in a low pressure oxygen atmosphere. The Al:Si ratio can be controlled via the separate plasma guns, and the film adhesion, structure and morphology can be controlled via the ion energy which in turn is controlled by the pulse bias voltage. The films are amorphous as-deposited, and crystalline mullite is formed by subsequent annealing at 1000 C for 2 hours in air. Adhesion between the aluminum-silicon oxide film and the substrate increases after this first annealing. They have tested the behavior of films when subjected to repetitive thermal cycling between room temperature and 1100 C, and found that the films retain their adhesion and quality. Here they review the plasma synthesis technique and the characteristics of the mullite films prepared in this way, and summarize the status of the thermal cycling experiments.

  7. Transparent lithiated polymer films for thermal neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Mabe, Andrew N., E-mail: andrew.n.mabe@gmail.com [Department of Chemistry, University of Tennessee, Knoxville, TN 37996 (United States); Auxier, John D. [Department of Chemistry, University of Tennessee, Knoxville, TN 37996 (United States); Urffer, Matthew J. [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Penumadu, Dayakar [Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Schweitzer, George K. [Department of Chemistry, University of Tennessee, Knoxville, TN 37996 (United States); Miller, Laurence F. [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States)

    2013-09-11

    Novel water-soluble {sup 6}Li loaded copolymer scintillation films have been designed and fabricated to detect thermal neutrons. Styrene and maleic anhydride were copolymerized to form an alternating copolymer, then the anhydride functionality was hydrolyzed using {sup 6}Li hydroxide. The resulting poly(styrene-co-lithium maleate) was mixed with salicylic acid as a fluor and cast as a thin film from water. The maximum {sup 6}Li loading obtained that resulted in a transparent film was 4.36% by mass ({sup 6}Li to polymer). The optimum fluorescence output was obtained for 11.7% salicylic acid by mass, presumably in the form of lithium salicylate, resulting in an optimum film containing 3.85% by mass of {sup 6}Li. A facile and robust synthesis method, film fabrication protocol, photoluminescence results, and scintillation responses are reported herein. -- Highlights: • A transparent polymer scintillator containing 3.85 wt% {sup 6}Li has been synthesized. • This class of polymeric thermal neutron scintillation detector is water-soluble. • Salicylic acid, presumably in the form of lithium salicylate, is used as a fluor. • The material emits 373 photons/α ({sup 241}Am) and an average of 139 photons/β ({sup 36}Cl). • The material emits 360 photons per thermal neutron capture event.

  8. 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 ...

  9. Synthesis and characterization of thermally oxidized ZnO films

    Indian Academy of Sciences (India)

    Administrator

    Synthesis and characterization of thermally oxidized ZnO films. A P RAMBU1,* and N IFTIMIE2 .... R. −. Δ. = = (1) where Ra is the sensor resistance in the air and Rg is the .... ple, Aida and coworkers (2006) reported that the total oxidation is ...

  10. Effect of thermal annealing of lead oxide film

    International Nuclear Information System (INIS)

    Hwang, Oh Hyeon; Kim, Sang Su; Suh, Jong Hee; Cho, Shin Hang; Kim, Ki Hyun; Hong, Jin Ki; Kim, Sun Ung

    2011-01-01

    Oxygen partial pressure in a growth process of lead oxide determines chemical and physical properties as well as crystalline structure. In order to supply oxygen, two ring-shape suppliers have been installed in a growth chamber. Films have been deposited using vacuum thermal evaporation from a raw material of yellow lead oxide powder (5N). Growth rate is controlled to be about 400 A/s, and film thickness more than 50 μm has been achieved. After deposition, the film is annealed at various temperatures under an oxygen atmosphere. In this study, an optimum growth condition for a good X-ray detector has been achieved by fine control of oxygen flow-rate and by thermal treatment. An electrical resistivity of 4.5x10 12 Ω cm is measured, and is comparable with the best data of PbO.

  11. Thermal conductivity of mesoporous films measured by Raman spectroscopy

    Science.gov (United States)

    Stoib, B.; Filser, S.; Petermann, N.; Wiggers, H.; Stutzmann, M.; Brandt, M. S.

    2014-04-01

    We measure the in-plane thermal conductance of mesoporous Ge and SiGe thin films using the Raman-shift method and, based on a finite differences simulation accounting for the geometry of the sample, extract the in-plane thermal conductivity. For a suspended thin film of laser-sintered SiGe nanoparticles doped with phosphorus, we find an effective in-plane thermal conductivity of 0.05 W/m K in vacuum for a temperature difference of 400 K and a mean temperature of 500 K. Under similar conditions, the effective in-plane thermal conductivity of a laser-sintered undoped Ge nanoparticle film is 0.5 W/m K. Accounting for a porosity of approximately 50%, the normalized thermal conductivities are 0.1 W/m K and 1 W/m K, respectively. The thermoelectric performance is discussed, considering that the electrical in-plane conductivity is also affected by the mesoporosity.

  12. Pre-treating water with non-thermal plasma

    Science.gov (United States)

    Cho, Young I.; Fridman, Alexander; Rabinovich, Alexander; Cho, Daniel J.

    2017-07-04

    The present invention consists of a method of pre-treatment of adulterated water for distillation, including adulterated water produced during hydraulic fracturing ("fracking") of shale rock during natural gas drilling. In particular, the invention is directed to a method of treating adulterated water, said adulterated water having an initial level of bicarbonate ion in a range of about 250 ppm to about 5000 ppm and an initial level of calcium ion in a range of about 500 ppm to about 50,000 ppm, said method comprising contacting the adulterated water with a non-thermal arc discharge plasma to produce plasma treated water having a level of bicarbonate ion of less than about 100 ppm. Optionally, the plasma treated water may be further distilled.

  13. Study of thermal and mechanical properties of PCL films

    International Nuclear Information System (INIS)

    Siqueira, A.R. de; Vieira, A.B. da Silva; Leite, I.F.

    2016-01-01

    In the current situation of the market, it is remarkable the concern for the development of materials that offer better properties and biodegradable behavior. The scientific researches seeks development and improvement of materials for applications in products increasingly biodegradable. To do so, this research aims at obtaining films composed of polymer poly(ε-caprolactone)(PCL), aliphatic polyester synthetic and biodegradable, and silicates in layers, specifically in the State of Paraiba, prepared by the method of solution. This mixture makes it possible to form different nanostructures intercalated morphology and/or exfoliated, which therefore provides improvement in the thermal properties of the final product. After analyzing the results of X-ray diffraction (XRD) was observed predominantly exfoliated morphologies to PCL films containing different silicate content and an increase in thermal stability when there was a lower concentration of clay as thermal analysis (TGA). (author)

  14. Using Mosaicity to Tune Thermal Transport in Polycrystalline AlN Thin Films

    KAUST Repository

    Singh, Shivkant

    2018-05-17

    The effect of controlling the c-axis alignment (mosaicity) to the cross-plane thermal transport in textured polycrystalline aluminum nitride (AlN) thin films is experimentally and theoretically investigated. We show that by controlling the sputtering conditions we are able to deposit AlN thin films with varying c-axis grain tilt (mosaicity) from 10° to 0°. Microstructural characterization shows that the films are nearly identical in thickness and grain size, and the difference in mosaicity alters the grain interface quality. This has a significant effect to thermal transport where a thermal conductivity of 4.22 W/mK vs. 8.09 W/mK are measured for samples with tilt angles of 10° vs. 0° respectively. The modified Callaway model was used to fit the theoretical curves to the experimental results using various phonon scattering mechanisms at the grain interface. It was found that using a non-gray model gives an overview of the phonon scattering at the grain boundaries, whereas treating the grain boundary as an array of dislocation lines with varying angle relative to the heat flow, best describes the mechanism of the thermal transport. Lastly, our results show that controlling the quality of the grain interface provides a tuning knob to control thermal transport in polycrystalline materials.

  15. Using Mosaicity to Tune Thermal Transport in Polycrystalline AlN Thin Films

    KAUST Repository

    Singh, Shivkant; Shervin, Shahab; Sun, Haiding; Yarali, Milad; Chen, Jie; Lin, Ronghui; Li, Kuang-Hui; Li, Xiaohang; Ryou, Jae-Hyun; Mavrokefalos, Anastassios

    2018-01-01

    The effect of controlling the c-axis alignment (mosaicity) to the cross-plane thermal transport in textured polycrystalline aluminum nitride (AlN) thin films is experimentally and theoretically investigated. We show that by controlling the sputtering conditions we are able to deposit AlN thin films with varying c-axis grain tilt (mosaicity) from 10° to 0°. Microstructural characterization shows that the films are nearly identical in thickness and grain size, and the difference in mosaicity alters the grain interface quality. This has a significant effect to thermal transport where a thermal conductivity of 4.22 W/mK vs. 8.09 W/mK are measured for samples with tilt angles of 10° vs. 0° respectively. The modified Callaway model was used to fit the theoretical curves to the experimental results using various phonon scattering mechanisms at the grain interface. It was found that using a non-gray model gives an overview of the phonon scattering at the grain boundaries, whereas treating the grain boundary as an array of dislocation lines with varying angle relative to the heat flow, best describes the mechanism of the thermal transport. Lastly, our results show that controlling the quality of the grain interface provides a tuning knob to control thermal transport in polycrystalline materials.

  16. Novel polypyrrole films with excellent crystallinity and good thermal stability

    International Nuclear Information System (INIS)

    Jeeju, Pullarkat P.; Varma, Sreekanth J.; Francis Xavier, Puthampadath A.; Sajimol, Augustine M.; Jayalekshmi, Sankaran

    2012-01-01

    Polypyrrole has drawn a lot of interest due to its high thermal and environmental stability in addition to high electrical conductivity. The present work highlights the enhanced crystallinity of polypyrrole films prepared from the redoped sample solution. Initially hydrochloric acid doped polypyrrole was prepared by chemical oxidative polymerization of pyrrole using ammonium peroxidisulphate as oxidant. The doped polypyrrole was dedoped using ammonia solution and then redoped with camphor sulphonic acid. Films were coated on ultrasonically cleaned glass substrates from the redoped sample solution in meta-cresol. The enhanced crystallinity of the polypyrrole films has been established from X-ray diffraction (XRD) studies. The room temperature electrical conductivity of the redoped polypyrrole film is about 30 times higher than that of the hydrochloric acid doped pellet sample. The results of Raman spectroscopy, Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) of the samples support the enhancement in crystallinity. Percentage crystallinity of the samples is estimated from XRD and DSC data. The present work is significant, since crystallinity of films is an important parameter for selecting polymers for specific applications. - Highlights: ► Polypyrrole films redoped with CSA have been prepared from meta-cresol solution. ► The solution casted films exhibit semi-crystallinity and good thermal stability. ► Percentage crystallinity estimated using XRD and DSC analysis is about 65%. ► Raman studies support the enhancement in crystallinity based on XRD and DSC data. ► The conductivity of the film is 30 times higher than that of HCl doped sample.

  17. Novel polypyrrole films with excellent crystallinity and good thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Jeeju, Pullarkat P., E-mail: jeejupp@gmail.com [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India); Varma, Sreekanth J.; Francis Xavier, Puthampadath A.; Sajimol, Augustine M. [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India); Jayalekshmi, Sankaran, E-mail: jayalekshmi@cusat.ac.in [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin-22, Kerala (India)

    2012-06-15

    Polypyrrole has drawn a lot of interest due to its high thermal and environmental stability in addition to high electrical conductivity. The present work highlights the enhanced crystallinity of polypyrrole films prepared from the redoped sample solution. Initially hydrochloric acid doped polypyrrole was prepared by chemical oxidative polymerization of pyrrole using ammonium peroxidisulphate as oxidant. The doped polypyrrole was dedoped using ammonia solution and then redoped with camphor sulphonic acid. Films were coated on ultrasonically cleaned glass substrates from the redoped sample solution in meta-cresol. The enhanced crystallinity of the polypyrrole films has been established from X-ray diffraction (XRD) studies. The room temperature electrical conductivity of the redoped polypyrrole film is about 30 times higher than that of the hydrochloric acid doped pellet sample. The results of Raman spectroscopy, Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA) of the samples support the enhancement in crystallinity. Percentage crystallinity of the samples is estimated from XRD and DSC data. The present work is significant, since crystallinity of films is an important parameter for selecting polymers for specific applications. - Highlights: Black-Right-Pointing-Pointer Polypyrrole films redoped with CSA have been prepared from meta-cresol solution. Black-Right-Pointing-Pointer The solution casted films exhibit semi-crystallinity and good thermal stability. Black-Right-Pointing-Pointer Percentage crystallinity estimated using XRD and DSC analysis is about 65%. Black-Right-Pointing-Pointer Raman studies support the enhancement in crystallinity based on XRD and DSC data. Black-Right-Pointing-Pointer The conductivity of the film is 30 times higher than that of HCl doped sample.

  18. Parametric Thermal Models of the Transient Reactor Test Facility (TREAT)

    Energy Technology Data Exchange (ETDEWEB)

    Bradley K. Heath

    2014-03-01

    This work supports the restart of transient testing in the United States using the Department of Energy’s Transient Reactor Test Facility at the Idaho National Laboratory. It also supports the Global Threat Reduction Initiative by reducing proliferation risk of high enriched uranium fuel. The work involves the creation of a nuclear fuel assembly model using the fuel performance code known as BISON. The model simulates the thermal behavior of a nuclear fuel assembly during steady state and transient operational modes. Additional models of the same geometry but differing material properties are created to perform parametric studies. The results show that fuel and cladding thermal conductivity have the greatest effect on fuel temperature under the steady state operational mode. Fuel density and fuel specific heat have the greatest effect for transient operational model. When considering a new fuel type it is recommended to use materials that decrease the specific heat of the fuel and the thermal conductivity of the fuel’s cladding in order to deal with higher density fuels that accompany the LEU conversion process. Data on the latest operating conditions of TREAT need to be attained in order to validate BISON’s results. BISON’s models for TREAT (material models, boundary convection models) are modest and need additional work to ensure accuracy and confidence in results.

  19. The disclosed transformation of pre-sputtered Ti films into nanoparticles via controlled thermal oxidation

    Science.gov (United States)

    Awad, M. A.; Raaif, M.

    2018-05-01

    Nanoparticles of TiO2 were successfully prepared from pre-sputtered Ti films using the controlled thermal oxidation. The effect of oxidation temperature on structural, morphological and optical properties in addition to photocatalysis activity of the sputtered films was tested and explained. Analysis of XRD and EDAX elucidated the enhancement in crystallization and oxygen content with the increase of oxidation temperature. SEM depicted the formation of very fine nanoparticles with no specific border on the films oxidized at 550 and 600 °C, whilst crystallites with larger size of approximately from 16 to 23 nm have been observed for the film oxidized at 650 °C. Both optical transmission and refractive index were increased with increasing the oxidation temperature. A red shift in the absorption edge was obtained for the films oxidized at 650 °C compared to that oxidized at 600 °C. The photocatalysis tests demonstrated the priority of 600 °C nanoparticle films to decompose methyl orange (MO) more than 650 °C treated film.

  20. Nutrients and heavy metal distribution in thermally treated pig manure

    DEFF Research Database (Denmark)

    Kuligowski, Ksawery; Poulsen, Tjalfe G.; Stoholm, Peder

    2008-01-01

    Ash from pig manure treated by combustion and thermal gasification was characterized and compared in terms of nutrient, i.e., potassium (K), phosphorus (P) and heavy metal, i.e., cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) contents. Total nutrient and metal concentrations...... that ash from gasified manure contained more water-extractable K in comparison with combusted manure whereas the opposite was the case with respect to P. Heavy metals Ni, Cr and Cd were present in higher concentrations in the fine particle size fractions (

  1. Distribution analysis of thermal effusivity for sub-micrometer YBCO thin films using thermal microscope

    International Nuclear Information System (INIS)

    Yagi, T.; Taketoshi, N.; Kato, H.

    2004-01-01

    Thermal effusivity measurements have been carried out for sub-micrometer YBCO superconducting films using thermal microscope based upon thermoreflectance technique. Two samples were prepared: c-axis aligned YBCO thin films with 800 nm in thickness synthesized on MgO and SrTiO 3 substrates. Measured thermal effusivities perpendicular to the surface, i.e. in parallel with c-axis were determined to be 1770 J/m 2 s 0.5 K on MgO substrate and 1420 J/m 2 s 0.5 K for that on SrTiO 3 substrate, respectively. The scatter of the measurements is estimated to be lower than ±5.2%. These values are consistent with reported values of YBCO single crystal in the direction of c-axis. In addition, 2D profiling image, that is, in-plane distribution of thermal effusivity was well obtained for the YBCO film on MgO substrate by operating this thermal microscope in a scanning mode. Its standard deviation of the in-plane thermal effusivity scattering due to the non-uniformity is evaluated to be ±5.7%

  2. Thermal Effusivity Determination of Metallic Films of Nanometric Thickness by the Electrical Micropulse Method

    Science.gov (United States)

    Lugo, J. M.; Oliva, A. I.

    2017-02-01

    The thermal effusivity of gold, aluminum, and copper thin films of nanometric thickness (20 nm to 200 nm) was investigated in terms of the films' thickness. The metallic thin films were deposited onto glass substrates by thermal evaporation, and the thermal effusivity was estimated by using experimental parameters such as the specific heat, thermal conductivity, and thermal diffusivity values obtained at room conditions. The specific heat, thermal conductivity, and thermal diffusivity values of the metallic thin films are determined with a methodology based on the behavior of the thermal profiles of the films when electrical pulses of few microseconds are applied at room conditions. For all the investigated materials, the thermal effusivity decreases with decreased thickness. The thermal effusivity values estimated by the presented methodology are consistent with other reported values obtained under vacuum conditions and more elaborated methodologies.

  3. Thermal Conductivity in Nanostructured Films: From Single Cellulose Nanocrystals to Bulk Films

    Science.gov (United States)

    Jairo A. Diaz; Zhijiang Ye; Xiawa Wu; Arden L. Moore; Robert J. Moon; Ashlie Martini; Dylan J. Boday; Jeffrey P. Youngblood

    2014-01-01

    We achieved a multiscale description of the thermal conductivity of cellulose nanocrystals (CNCs) from single CNCs (~­0.72−5.7 W m−1 K−1) to their organized nanostructured films (~­0.22−0.53 W m−1 K−1) using...

  4. Far-infrared spectroscopy of thermally annealed tungsten silicide films

    International Nuclear Information System (INIS)

    Amiotti, M.; Borghesi, A.; Guizzetti, G.; Nava, F.; Santoro, G.

    1991-01-01

    The far-infrared transmittance spectrum of tungsten silicide has been observed for the first time. WSi 2 polycrystalline films were prepared by coevaporation and chemical-vapour deposition on silicon wafers, and subsequently thermally annealed at different temperatures. The observed structures are interpreted, on the basis of the symmetry properties of the crystal, such as infrared-active vibrational modes. Moreover, the marked lineshape dependence on annealing temperature enables this technique to analyse the formation of the solid silicide phases

  5. Thermal analysis of compositionally modulated Fe/Y films

    International Nuclear Information System (INIS)

    Kajiura, M.; Morishita, T.; Togami, Y.; Tsushima, K.

    1987-01-01

    Structures of compositionally modulated Fe/Y films were studied by thermal analysis. The exothermic peak found in the DSC curve of (Fe 12 A/Y 12 A) most probably corresponds to crystallization of an amorphous material. SEM analysis suggested that the composition of crystallized (Fe 12 A/Y 12 A) was YFe2. It is concluded that a compositionally modulated (Fe 12 A/Y 12 A) is amorphous in structure as well as in magnetic properties

  6. Characteristics of residues from thermally treated anaerobic sludges

    International Nuclear Information System (INIS)

    Friedman, A.A.; Smith, J.E.; De Santis, J.; Ptak, T.; Ganley, R.C.

    1988-01-01

    Sludge management and disposal are probably the most difficult and expensive operations involved in wastewater treatment today. To minimize final disposal costs many waste treatment facilities practice some form of anaerobic digestion and dewatering to reduce the volume and offensiveness of their by-product sludges. One potential alternative for reducing sludge volumes consists of high temperature, partial oxidation of these previously digested sludges (PDS) and subsequent anaerobic biological conversion of resulting soluble organics to methane. This paper describes solids destruction, residue characteristics and biodegradability factors that should be considered in the design of liquid thermal treatment processes for the management of anaerobic sludges. To date only very limited information is available concerning the suitability of thermally treated PDS to serve as a substrate for the generation of methane. The primary objective of this research was to determine the feasibility of producing methane efficiently from the residual VSS in anaerobically digested sludges. Secondary goals were to establish the ''best'' conditions for thermal treatment for solubilizing PDS, to observe the effect of the soluble products on methanogenesis and to evaluate process sidestreams for dewaterability and anaerobic biodegradability

  7. Decomposition of thermally unstable substances in film evaporators

    Energy Technology Data Exchange (ETDEWEB)

    Matz, G

    1982-10-01

    It is widely known that film evaporators are considered to permit really gentle evaporation of heat-sensitive substances. Nevertheless, decomposition of such substance still occurs to an extent depending upon the design and operation of the evaporator. In the following a distinction is made between evaporators with films not generated mechanically, namely the long tube evaporator (lTE) or climbing film evaporator, the falling film evaporator (FFE) and the multiple phase helical tube (MPT) or helical coil evaporators (TFE). Figs 1 and 2 illustrate the mode of operation. A theory of the decomposition of thermally unstable substances in these evaporators is briefly outlined and compared with measurements. Such a theory cannot be developed without any experimental checks; on the other hand, meausrements urgently need a theoretical basis if only to establish what actually has to be measured. All experiments are made with a system of readily adjustable decomposability, namely with aqueous solutions of saccharose; the thermal inversion of this compound can be controlled by addition of various amounts or concentrations of hydrochloric acid. In the absence of any catalysis by hydrochloric acid, the decomposition rates within in the temperature interval studied (60-130/sup 0/C) are so low that the experiments would take much too long and determination of the concentration differences (generally by polarimetric methods) would be very complicated. Such slight effects would also be very unfavourable for comparison with theory. (orig.)

  8. Films of chitin, chitosan and cellulose obtained from aqueous suspension treated by irradiation of high intensity ultrasound; Filmes de quitina, quitosana e celullose de sisal obtidos a partir de suspensoes aquosas tratadas com irradiacao de ultrassom de alta intensidade

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Erika V.R.; Mariano, Mario S.; Campana-Filho, Sergio P., E-mail: erikavi@iqsc.usp.br [Universidade de Sao Paulo (IQSC/USP), Instituto de Quimica de Sao Carlos, Sao Carlos, SP (Brazil)

    2011-07-01

    Films of chitin, chitin/chitosan and chitin/sisal cellulose were obtained by casting their aqueous suspensions previously treated with irradiation of high intensity ultrasound. The films were characterized for surface morphology by scanning electron microscopy and it is possible notice that the films containing chitosan are much more homogeneous. The thermal behavior of the films was evaluated by dynamic mechanical thermal analysis, differential scanning calorimetry, and thermogravimetric analysis and revealing similarity in comparison with the thermal behavior of polysaccharide isolated. The tensile strength was determined and the film containing chitosan showed the best result when compared to other films. The crystallinity index of the films analyzed by X-ray diffraction showed that the films are amorphous material. The analysis by infrared spectroscopy showed that treatment of aqueous suspensions of polysaccharides with irradiation of high intensity ultrasound did not change the chemical structure of polymers. The crystallinity index was determined by X-ray diffraction, revealing that the films are amorphous materials. The results of this study indicate the possibility of processing of chitin, chitosan and cellulose, polysaccharides whose solubilities are limited to a few solvent systems, by treating their aqueous suspensions with high intensity ultrasound. (author)

  9. Wide-range measurement of thermal effusivity using molybdenum thin film with low thermal conductivity for thermal microscopes

    Science.gov (United States)

    Miyake, Shugo; Matsui, Genzou; Ohta, Hiromichi; Hatori, Kimihito; Taguchi, Kohei; Yamamoto, Suguru

    2017-07-01

    Thermal microscopes are a useful technology to investigate the spatial distribution of the thermal transport properties of various materials. However, for high thermal effusivity materials, the estimated values of thermophysical parameters based on the conventional 1D heat flow model are known to be higher than the values of materials in the literature. Here, we present a new procedure to solve the problem which calculates the theoretical temperature response with the 3D heat flow and measures reference materials which involve known values of thermal effusivity and heat capacity. In general, a complicated numerical iterative method and many thermophysical parameters are required for the calculation in the 3D heat flow model. Here, we devised a simple procedure by using a molybdenum (Mo) thin film with low thermal conductivity on the sample surface, enabling us to measure over a wide thermal effusivity range for various materials.

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

    Science.gov (United States)

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

    2016-05-01

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

  12. Optical properties on thermally evaporated and heat-treated ...

    Indian Academy of Sciences (India)

    Administrator

    of the intra-molecular bonds between the powder compounds and thin films. The optical ... Keywords. Phthalocyanine; thin films; optical properties; absorption spectra. 1. .... Leica Cambridge scanning electron microscope (model. Stereoscan ...

  13. The absorption of thermal radiation by water films

    International Nuclear Information System (INIS)

    Pearson, K.G.; Elliott, D.

    1977-04-01

    Except at the shortest wavelengths (i.e. <2μm) liquid water is relatively opaque to thermal radiation. It is also a poor reflector, reflecting back only about 2% of normal incident radiation. It is shown that when radiation falls on a plane water surface from a parallel heated surface about 93.5% of the incident radiation enters the surface, the remaining 6.5% being reflected back to the source. It is also shown that, for source temperatures up to the maximum of interest in reactor safety studies, a large fraction of the thermal radiation which enters the water is absorbed on passing through a distance approaching 0.5 mm. Since liquid water films of such thickness can be expected to exist on the pressure tubes of an SGHWR following a loss of coolant accident it follows that, irrespective of the condition of the pressure tube wall, the absorptivity of the pressure tubes will in effect be about 0.9. Data are presented for experiments performed to determine the absorptivity of water films on a polished surface whose dry absorptivity was measured to be 0.18. The presence of the water film, of estimated thickness 0.3 mm, increased the absorptivity of the surface to a value close to unity. (author)

  14. Investigations of the thermal treatment effect on the generation of cadmium sulfide clusters in polymeric films

    International Nuclear Information System (INIS)

    Stanculescu, Anca; Socol, M.; Stanculescu, F.

    2002-01-01

    In the last years a special interest has been paid to the field of nanometer-sized semiconductor compound crystalline clusters synthesized in different matrix (inorganic or organic), due to their special physical and chemical properties intermediate between the molecular and bulk limits. To obtain the thin film samples of CdS particles embedded in a polymeric transparent matrix, as bisphenol A polycarbonate, we followed a process containing three important steps: preparation of the so-called 'mother solution', film deposition and thermal treatment. The samples obtained after the first two steps were heat treated at different temperatures (90 deg. C and 150 deg. C) for 0.5 h, 1 h and 1.5 h, and we have analyzed the influence of these parameters on the film quality using UV-VIS spectrophotometric methods. This paper presents a study of the influence of the thermal treatment on the CdS clusters' generation process and film quality and homogeneity. The parameters of the processing procedure of the polymeric film, as the cooling rate, have a great influence on the rate of germination and development of the crystalline phase. A slow cooling rate is a more favorable process for CdS clusters' formation, indicated .by structured features of the fundamental absorption situated between 350-450 nm. When the temperature for thermal treatment increases to 90 deg. C a sharp rise and a shift to shorter wavelengths of the absorption onset edge was observed. This shift proves the existence of a weak quantum confinement effects. We concluded that these two parameters have some equivalent effects on the CdS clusters' generation in polymeric matrix. Varying the treatment duration with a fixed temperature produces similar results as the fixed duration, varied temperature treatment. (authors)

  15. Mechanical and thermal properties of physically-blended-plastic films

    International Nuclear Information System (INIS)

    Abu Issa, M. S.

    1983-10-01

    Low density polyethylene (LDPE) and isotactic polypropylene (PP) blend were produced in film form and were characterized by a number of techniques such as wide-angle x-ray diffraction (WAXD), differential thermal analysis (DTA), scanning electron microscopy (SEM), and instron tensile testing. Results of WAXD and DTA showed conclusively that the two components in the blend are incompatible. SEM micrographs indicated that the 60/40 and 40/60 PP/PE blends show approximately fine homogeneous dispersion of the minor component into the matrix of the major component. The mechanical properties of the blend films improved with respect to the PE homo polymer. The improvement was more remarkable with the increase of the PP component in the blend. Results obtained in this work were explained in terms of crystallinity and the crystallite orientation. 28 refs., 29 figs., 5 tabs. (A.M.H.)

  16. Thermal Stress Behavior of Micro- and Nano-Size Aluminum Films

    International Nuclear Information System (INIS)

    Hanabusa, T.; Kusaka, K.; Nishida, M.

    2008-01-01

    In-situ observation of thermal stresses in thin films deposited on silicon substrate was made by X-ray and synchrotron radiation. Specimens prepared in this experiment were micro- and nano-size thin aluminum films with and without passivation film. The thickness of the film was 1 micrometer for micro-size films and 10, 20 and 50 nanometer for nano-size films. The stress measurement in micro-size films was made by X-ray radiation whereas the measurement of nano-size films was made by synchrotron radiation. Residual stress measurement revealed tensile stresses in all as-deposited films. Thermal stresses were measured in a series of heating- and cooling-stage. Thermal stress behavior of micro-size films revealed hysteresis loop during a heating and cooling process. The width of a hysteresis loop was larger in passivated film that unpassivated film. No hysteresis loops were observed in nano-size films with SiO 2 passivation. Strengthning mechanism in thin films was discussed on a passivation film and a film thickness

  17. Electronic properties of thermally formed thin iron oxide films

    International Nuclear Information System (INIS)

    Wielant, J.; Goossens, V.; Hausbrand, R.; Terryn, H.

    2007-01-01

    The oxide layer, present between an organic coating and the substrate, guarantees adhesion of the coating and plays a determinating role in the delamination rate of the organic coating. The purpose of this study is to compare the resistive and semiconducting properties of thermal oxides formed on steel in two different atmospheres at 250 deg. C: an oxygen rich atmosphere, air, and an oxygen deficient atmosphere, N 2 . In N 2 , a magnetite layer grows while in air a duplex oxide film forms composed by an inner magnetite layer and a thin outer hematite scale. The heat treatment for different amounts of time at high temperature was used as method to sample the thickness variation and change in electronic and semiconducting properties of the thermal oxide layers. Firstly, linear voltammetric measurements were performed to have a first insight in the electrochemical behavior of the thermal oxides in a borate buffer solution. Electrochemical impedance spectroscopy in the same buffer combined with the Mott-Schottky analysis were used to determine the semiconducting properties of the thermal oxides. By spectroscopic ellipsometry (SE) and atomic force microscopy (AFM), respectively, the thickness and roughness of the oxide layers were determined supporting the physical interpretation of the voltammetric and EIS data. These measurements clearly showed that oxide layers with different constitution, oxide resistance, flatband potential and doping concentration can be grown by changing the atmosphere

  18. Fluoropolymer coated alanine films treated by atmospheric pressure plasmas − In comparison with gamma irradiation

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Bardenshtein, Alexander; Morgen, Per

    2018-01-01

    Fluoropolymer coated alanine films are treated by a dielectric barrier discharge and a gliding arc at atmospheric pressure as well as with gamma irradiation. The film surfaces and the underlying bulk materials are characterized before and after each treatment. The fluorine content decreases...

  19. Aligned silane-treated MWCNT/liquid crystal polymer films

    International Nuclear Information System (INIS)

    Cervini, Raoul; Simon, George P; Ginic-Markovic, Milena; Matisons, Janis G; Huynh, Chi; Hawkins, Stephen

    2008-01-01

    We report on a method to preferentially align multiwall carbon nanotubes (MWCNTs) in a liquid crystalline matrix to form stable composite thin films. The liquid crystalline monomeric chains can be crosslinked to form acrylate bridges, thereby retaining the nanotube alignment. Further post-treatment by ozone etching of the composite films leads to an increase in bulk conductivity, leading to higher emission currents when examined under conducting scanning probe microscopy. The described methodology may facilitate device manufacture where electron emission from nanosized tips is important in the creation of new display devices

  20. Properties of CuS thin films treated in air plasma

    International Nuclear Information System (INIS)

    Rodriguez-Lazcano, Y.; Martinez, H.; Calixto-Rodriguez, M.; Nunez Rodriguez, A.

    2009-01-01

    Copper sulfide thin films were grown by chemical deposition and post treated in air plasma during 20 min. Air plasma was generated by alternating current discharge at a pressure of 4 x 10 2 Pa. The power discharge was maintained at an output of 220 V and a current of 0.2 A. Thermal annealing at 300 o C was performed for comparison. X-ray diffraction shows that plasma treatment results in phase transformation of Cu 39 S 28 (as grown) to CuS (treated by plasma). The copper lost is confirmed by X-ray fluorescence. No significant change in the optical band gap was observed due to plasma action. In addition, the electrical conductivity increases in one order of magnitude. On the other hand, the samples under plasma condition show a parallel growth to the substrate and an increase in the surface uniformity. The plasma etching removes copper due to its affinity with oxygen to form CuO, as is corroborated by optical emission spectroscopy.

  1. Fabrication of oxide-free graphene suspension and transparent thin films using amide solvent and thermal treatment

    International Nuclear Information System (INIS)

    Oh, Se Young; Kim, Sung Hwan; Chi, Yong Seung; Kang, Tae Jin

    2012-01-01

    Graphical abstract: New methodology for suspended graphene sheets of high-quality (oxide-free), high-yield (high concentration) using amide solvent exfoliation and thermal treatment at 800 °C. We confirmed that the van der Waals force between the graphene layers decreases as increasing thermal treatment temperatures as shown XRD data (b). Highlights: ► Propose of new methodology to prepare oxide-free graphene sheets suspension. ► The graphene suspension concentration is enhanced by thermal treatment. ► Decrease of van der Waals force between the graphene layers by high temperature and pressure. ► This method has the potential as technology for mass production. ► It could be applied in transparent and flexible electronic devices. - Abstract: High quality graphene sheets were produced from graphite by liquid phase exfoliation using N-methyl-2-pyrrolidone (NMP) and a subsequent thermal treatment to enhance the exfoliation. The exfoliation was enhanced by treatment with organic solvent and high thermal expansion producing high yields of the high-quality and defect-free graphene sheets. The graphene was successfully deposited on a flexible and transparent polymer film using the vacuum filtration method. SEM images of thin films of graphene treated at 800 °C showed uniform structure with no defects commonly found in films made of graphene produced by other techniques. Thin films of graphene prepared at higher temperatures showed superior transmittance and conductivity. The sheet-resistance of the graphene film treated at 800 °C was 2.8 × 10 3 kΩ/□ with 80% transmittance.

  2. Corrugated paraffin nanocomposite films as large stroke thermal actuators and self-activating thermal interfaces.

    Science.gov (United States)

    Copic, Davor; Hart, A John

    2015-04-22

    High performance active materials are of rapidly growing interest for applications including soft robotics, microfluidic systems, and morphing composites. In particular, paraffin wax has been used to actuate miniature pumps, solenoid valves, and composite fibers, yet its deployment is typically limited by the need for external volume constraint. We demonstrate that compact, high-performance paraffin actuators can be made by confining paraffin within vertically aligned carbon nanotube (CNT) films. This large-stroke vertical actuation is enabled by strong capillary interaction between paraffin and CNTs and by engineering the CNT morphology by mechanical compression before capillary-driven infiltration of the molten paraffin. The maximum actuation strain of the corrugated CNT-paraffin films (∼0.02-0.2) is comparable to natural muscle, yet the maximum stress is limited to ∼10 kPa by collapse of the CNT network. We also show how a CNT-paraffin film can serve as a self-activating thermal interface that closes a gap when it is heated. These new CNT-paraffin film actuators could be produced by large-area CNT growth, infiltration, and lamination methods, and are attractive for use in miniature systems due to their self-contained design.

  3. Surface and sub-surface thermal oxidation of thin ruthenium films

    NARCIS (Netherlands)

    Coloma Ribera, R.; van de Kruijs, Robbert Wilhelmus Elisabeth; Kokke, S.; Zoethout, E.; Yakshin, Andrey; Bijkerk, Frederik

    2014-01-01

    A mixed 2D (film) and 3D (nano-column) growth of ruthenium oxide has been experimentally observed for thermally oxidized polycrystalline ruthenium thin films. Furthermore, in situ x-ray reflectivity upon annealing allowed the detection of 2D film growth as two separate layers consisting of low

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

    Indian Academy of Sciences (India)

    Unknown

    Thermal diffusivity and conductivity in these films decrease at least two orders compared with bulk. ... Afifi et al. (1986) prepared evaporated thin film on glass substrate. ... phase of CdS and the identification of the peaks indicate that the film is ...

  5. Thermal Expansion of Self-Organized and Shear-Oriented Cellulose Nanocrystal Films

    Science.gov (United States)

    Jairo A. Diaz; Xiawa Wu; Ashlie Martini; Jeffrey P. Youngblood; Robert J. Moon

    2013-01-01

    The coefficient of thermal expansion (CTE) of cellulose nanocrystal (CNC) films was characterized using novel experimental techniques complemented by molecular simulations. The characteristic birefringence exhibited by CNC films was utilized to calculate the in-plane CTE of selforganized and shear-oriented self-standing CNC films from room temperature to 100 °...

  6. The thermal stability of the carbon-palladium films for hydrogen sensor applications

    Science.gov (United States)

    Rymarczyk, Joanna; Czerwosz, ElŻbieta; Diduszko, Ryszard; Kozłowski, Mirosław

    2017-08-01

    The thermal stability of two types of C-Pd films prepared in PVD process were studied. These films are composed of Pd nanograins embedded in a multiphase carbonaceous matrix. These films were distinguished by Pd content. These films were annealed in a range of temperatures 50÷1000°C. The structural, topographical and molecular changes were studied by scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and X-ray diffraction (XRD) methods. The results show that investigated films are thermally stable up to 200°C.

  7. Extending the 3ω method: thermal conductivity characterization of thin films.

    Science.gov (United States)

    Bodenschatz, Nico; Liemert, André; Schnurr, Sebastian; Wiedwald, Ulf; Ziemann, Paul

    2013-08-01

    A lock-in technique for measurement of thermal conductivity and volumetric heat capacity of thin films is presented. The technique is based on the 3ω approach using electrical generation and detection of oscillatory heat along a thin metal strip. Thin films are deposited onto the backside of commercial silicon nitride membranes, forming a bilayer geometry with distinct thermal parameters. Stepwise comparison to an adapted heat diffusion model delivers these parameters for both layers. Highest sensitivity is found for metallic thin films.

  8. X-ray photoelectron spectroscopy study of excimer laser treated alumina films

    Science.gov (United States)

    Georgiev, D. G.; Kolev, K.; Laude, L. D.; Mednikarov, B.; Starbov, N.

    1998-01-01

    Amorphous alumina layers are deposited on a single crystal Si substrate by a e-gun evaporation technique. These films are then thermally annealed in oxygen to be crystallized and, further, irradiated with an excimer laser beam. At each stage of the film preparation, an x-ray photoelectron spectroscopy analysis is performed at the film surface and in depth, upon ion beam grinding. Results give evidence for the formation of an aluminosilicate upon thermal annealing of the film in oxygen. At the surface itself, this compound is observed to decompose upon excimer laser irradiation at energy densities exceeding 1.75 J/cm2, giving rise to free Si atoms and SiO2, however with complete disappearance of Al atoms. Model photochemical reactions are proposed to explain such transformations.

  9. Modification of mechanical and thermal property of chitosan-starch blend films

    Science.gov (United States)

    Tuhin, Mohammad O.; Rahman, Nazia; Haque, M. E.; Khan, Ruhul A.; Dafader, N. C.; Islam, Rafiqul; Nurnabi, Mohammad; Tonny, Wafa

    2012-10-01

    Chitosan-starch blend films (thickness 0.2 mm) of different composition were prepared by casting and their mechanical properties were studied. To improve the properties of chitosan-starch films, glycerol and mustard oil of different composition were used. Chitosan-starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. The modified films showed improvement in both tensile strength and elongation at break than the pure chitosan-starch films. Water uptake of the films reduced significantly than the pure chitosan-starch film. Thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the modified films experience less thermal degradation than the pure films. Scanning electron microscopy (SEM) and FTIR were used to investigate the morphology and molecular interaction of the blend film, respectively.

  10. Thermal degradation kinetics and estimation of lifetime of radiation grafted polypropylene films

    International Nuclear Information System (INIS)

    Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Bhalla, Vinod Kumar

    2017-01-01

    In this research work, thermal stability and degradation behavior of acrylic acid grafted polypropylene (PP-g-PAAc) films were investigated by using thermogravimetric (TGA) analysis at four different heating rates 5, 10, 15 and 20 °C/min over a temperature range of 40–550 °C in nitrogen atmosphere. The kinetic parameters namely activation energy (E a ), reaction order (n) and frequency factor (Z) were calculated by three multiple heating rate methods. The thermal stability of PP-g-PAAc films is found to decrease with increase in degree of grafting. The TGA data and thermal kinetic parameters were also used to predict the lifetime of grafted PP films. The estimated lifetime of neat PP as well as grafted PP decreased with increase in temperature by all the three methods. Studies also indicated that E a and lifetime of PP-g-PAAc films decreased with increase in degree of grafting, which may also be helpful in biodegradation of grafted PP films. - Highlights: • Thermal stability of grafted polypropylene films have been observed lower than for neat polypropylene film. • Multiple heating rate methods have been used for determination of activation energy. • Activation energies of grafted polypropylene films were lower than polypropylene film. • The lifetimes of grafted polypropylene films were shorter than for neat polypropylene film.

  11. Phonon impedance matching: minimizing interfacial thermal resistance of thin films

    Science.gov (United States)

    Polanco, Carlos; Zhang, Jingjie; Ghosh, Avik

    2014-03-01

    The challenge to minimize interfacial thermal resistance is to allow a broad band spectrum of phonons, with non-linear dispersion and well defined translational and rotational symmetries, to cross the interface. We explain how to minimize this resistance using a frequency dependent broadening matrix that generalizes the notion of acoustic impedance to the whole phonon spectrum including symmetries. We show how to ``match'' two given materials by joining them with a single atomic layer, with a multilayer material and with a graded superlattice. Atomic layer ``matching'' requires a layer with a mass close to the arithmetic mean (or spring constant close to the harmonic mean) to favor high frequency phonon transmission. For multilayer ``matching,'' we want a material with a broadening close to the geometric mean to maximize transmission peaks. For graded superlattices, a continuous sequence of geometric means translates to an exponentially varying broadening that generates a wide-band antireflection coating for both the coherent and incoherent limits. Our results are supported by ``first principles'' calculations of thermal conductance for GaAs / Gax Al1 - x As / AlAs thin films using the Non-Equilibrium Greens Function formalism coupled with Density Functional Perturbation Theory. NSF-CAREER (QMHP 1028883), NSF-IDR (CBET 1134311), XSEDE.

  12. 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.

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

    Science.gov (United States)

    Shin, Joong-Won; Cho, Won-Ju

    2017-07-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bellido-Aguilar, Daniel Angel; Tofanello, Aryane [Centro de Ciências Naturais e Humanas (CCNH), Universidade Federal do ABC, Av. dos Estados N°5001, Bangu, Santo André, São Paulo CEP 09210-580 (Brazil); Souza, Flavio L., E-mail: flavio.souza@ufabc.edu.br [Centro de Ciências Naturais e Humanas (CCNH), Universidade Federal do ABC, Av. dos Estados N°5001, Bangu, Santo André, São Paulo CEP 09210-580 (Brazil); Furini, Leonardo Negri; Constantino, Carlos José Leopoldo [Faculdade de Ciências e Tecnologia (FCT), UNESP Univ Estadual Paulista, Presidente Prudente, São Paulo, 19060-900 (Brazil)

    2016-04-01

    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{sup 2+} and Sn{sup 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{sup 2+} or Sn{sup 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{sup 2+} and Sn{sup 4+} dopants affected differently the photocurrent onset potentials. • Dopants affected the grain size due to their segregation at grain boundaries.

  16. Amorphous Silicon-Germanium Films with Embedded Nanocrystals for Thermal Detectors with Very High Sensitivity

    Directory of Open Access Journals (Sweden)

    Cesar Calleja

    2016-01-01

    Full Text Available We have optimized the deposition conditions of amorphous silicon-germanium films with embedded nanocrystals in a plasma enhanced chemical vapor deposition (PECVD reactor, working at a standard frequency of 13.56 MHz. The objective was to produce films with very large Temperature Coefficient of Resistance (TCR, which is a signature of the sensitivity in thermal detectors (microbolometers. Morphological, electrical, and optical characterization were performed in the films, and we found optimal conditions for obtaining films with very high values of thermal coefficient of resistance (TCR = 7.9% K−1. Our results show that amorphous silicon-germanium films with embedded nanocrystals can be used as thermosensitive films in high performance infrared focal plane arrays (IRFPAs used in commercial thermal cameras.

  17. Amorphous Silicon-Germanium Films with Embedded Nano crystals for Thermal Detectors with Very High Sensitivity

    International Nuclear Information System (INIS)

    Calleja, C.; Torres, A.; Rosales-Quintero, P.; Moreno, M.

    2016-01-01

    We have optimized the deposition conditions of amorphous silicon-germanium films with embedded nano crystals in a plasma enhanced chemical vapor deposition (PECVD) reactor, working at a standard frequency of 13.56 MHz. The objective was to produce films with very large Temperature Coefficient of Resistance (TCR), which is a signature of the sensitivity in thermal detectors (micro bolometers). Morphological, electrical, and optical characterization were performed in the films, and we found optimal conditions for obtaining films with very high values of thermal coefficient of resistance (TCR = 7.9%K -1 ). Our results show that amorphous silicon-germanium films with embedded nano crystals can be used as thermo sensitive films in high performance infrared focal plane arrays (IRFPAs) used in commercial thermal cameras.

  18. 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.

  19. Thermal neutron imaging through XRQA2 GAFCHROMIC films coupled with a cadmium radiator

    Energy Technology Data Exchange (ETDEWEB)

    Sacco, D. [INFN – LNF, Via E. Fermi n.40, Frascati, 00044 Roma (Italy); INAIL – DIT, Via di Fontana Candida n.1, 00040 Monteporzio Catone (Italy); Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN – LNF, Via E. Fermi n.40, Frascati, 00044 Roma (Italy); Bortot, D. [Politecnico di Milano, Dipartimento di Energia, Via La Masa 34, 20156 Milano (Italy); INFN – Milano, Via Celoria16, 20133 Milano (Italy); Palomba, M. [ENEA Casaccia, Via Anguillarese, 301, S. Maria di Galeria, 00123 Roma (Italy); Pola, A. [Politecnico di Milano, Dipartimento di Energia, Via La Masa 34, 20156 Milano (Italy); INFN – Milano, Via Celoria16, 20133 Milano (Italy); Introini, M.V.; Lorenzoli, M. [Politecnico di Milano, Dipartimento di Energia, Via La Masa 34, 20156 Milano (Italy); Gentile, A. [INFN – LNF, Via E. Fermi n.40, Frascati, 00044 Roma (Italy); Strigari, L. [Laboratory of Medical Physics, Regina Elena National Cancer Institute, Via E. Chianesi 53, 00144 Roma (Italy); Pressello, C. [Department of Medical Physics, Azienda Ospedaliera San Camillo Forlanini, Circonvallazione Gianicolense 87, 00152 Roma (Italy); Soriani, A. [Laboratory of Medical Physics, Regina Elena National Cancer Institute, Via E. Chianesi 53, 00144 Roma (Italy); Gómez-Ros, J.M. [INFN – LNF, Via E. Fermi n.40, Frascati, 00044 Roma (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain)

    2015-10-21

    A simple and inexpensive method to perform passive thermal neutron imaging on large areas was developed on the basis of XRQA2 GAFCHROMIC films, commonly employed for quality assurance in radiology. To enhance their thermal neutron response, the sensitive face of film was coupled with a 1 mm thick cadmium radiator, forming a sandwich. By exchanging the order of Cd filter and sensitive film with respect to the incident neutron beam direction, two different configurations (beam-Cd-film and beam-film-Cd) were identified. These configurations were tested at thermal neutrons fluence values in the range 10{sup 9}–10{sup 10} cm{sup −2}, using the ex-core radial thermal neutron column of the ENEA Casaccia – TRIGA reactor. The results are presented in this work.

  20. A Sandwiched/Cracked Flexible Film for Multi-Thermal Monitoring and Switching Devices

    KAUST Repository

    Tai, Yanlong

    2017-08-30

    Polydimethylsiloxane (PDMS)-based flexible films have substantiated advantages in various sensing applications. Here, we demonstrate the highly sensitive and programmable thermal-sensing capability (thermal index, B, up to 126 × 103 K) of flexible films with tunable sandwiched microstructures (PDMS/cracked single-walled carbon nanotube (SWCNT) film/PDMS) when a thermal stimulus is applied. We found that this excellent performance results from the following features of the film\\'s structural and material design: (1) the sandwiched structure allows the film to switch from a three-dimensional to a two-dimensional in-plane deformation and (2) the stiffness of the SWCNT film is decreased by introducing microcracks that make deformation easy and that promote the macroscopic piezoresistive behavior of SWCNT crack islands and the microscopic piezoresistive behavior of SWCNT bundles. The PDMS layer is characterized by a high coefficient of thermal expansion (α = 310 × 10-6 K-1) and low stiffness (∼2 MPa) that allow for greater flexibility and higher temperature sensitivity. We determined the efficacy of our sandwiched, cracked, flexible films in monitoring and switching flexible devices when subjected to various stimuli, including thermal conduction, thermal radiation, and light radiation.

  1. Thermal treating of acrylic matrices as a tool for controlling drug release.

    Science.gov (United States)

    Hasanzadeh, Davood; Ghaffari, Solmaz; Monajjemzadeh, Farnaz; Al-Hallak, M H D-Kamal; Soltani, Ghazal; Azarmi, Shirzad

    2009-12-01

    The purpose of the present study was to investigate the effect of thermal-treating on the release of ibuprofen from the granules prepared using aqueous dispersions of Eudragit. To accomplish this goal, different formulations were prepared using wet granulation method containing two different types of Eudragit aqueous dispersions, RS30D, RL30D and Avicel as filler. Tablets were prepared using direct compression method. The prepared tablets were thermally treated at 50 and 70 degrees C for 24 h. The drug release from tablets was assessed before and after thermal-treating. The results of release study showed that, thermally-treating the tablets at the temperatures higher than glass transition temperature (Tg) of the polymer can decrease the drug release from matrices. For mechanistic evaluation of the effect of thermal-treating, powder X-ray diffraction (XPD), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), Fourier transform infrared (FT-IR) and helium pycnometer have been employed. The SEM graphs showed that the tablets have smoother surface with less porosity after thermal-treating. FT-IR spectra showed no change in the spectrum of thermally-treated tablet compared to control. In DSC graphs, no crystalline change was seen in the heat-treated samples of ibuprofen tablets, but decreased and widened peak size were related to the probable formation of solid solution of ibuprofen in Eudragit matrix. The results of helium pycnometer showed a significant decrease in the total porosity of some heat-treated samples. This study revealed the importance of thermal treating on the drug release from sustained release tablets containing Eudragit polymer.

  2. Development of oxidised and heat-moisture treated potato starch film.

    Science.gov (United States)

    Zavareze, Elessandra da Rosa; Pinto, Vânia Zanella; Klein, Bruna; El Halal, Shanise Lisie Mello; Elias, Moacir Cardoso; Prentice-Hernández, Carlos; Dias, Alvaro Renato Guerra

    2012-05-01

    This study investigated the effects of sodium hypochlorite oxidation and a heat-moisture treatment of potato starch on the physicochemical, pasting and textural properties of potato starches in addition to the water vapour permeability (WVP) and mechanical properties of potato starch films produced from these starches. The carbonyl contents, carboxyl contents, swelling power, solubility, pasting properties and gel texture of the native, oxidised and heat-moisture treated (HMT) starches were evaluated. The films made of native, oxidised and HMT starches were characterised by thickness, water solubility, colour, opacity, mechanical properties and WVP. The oxidised and HMT starches had lower viscosity and swelling power compared to the native starch. The films produced from oxidised potato starch had decreased solubility, elongation and WVP values in addition to increased tensile strength compared to the native starch films. The HMT starch increased the tensile strength and WVP of the starch films compared to the native starch. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Amorphous hydrogenated carbon films treated by SF{sub 6} plasma

    Energy Technology Data Exchange (ETDEWEB)

    Marins, N M S; Mota, R P; Santos, D C R; Honda, R Y; Kayama, M E; Kostov, K G; Algatti, M A [Laboratorio de Plasma, Faculdade de Engenharia, UNESP, Av. Dr. Ariberto Pereira da Cunha-333, 12516-410, Guaratingueta, SP (Brazil); Cruz, N C; Rangel, E C, E-mail: nazir@feg.unesp.b [Laboratorio de Plasmas Tecnologicos, Unidade Diferenciada Sorocaba/Ipero, UNESP, Av. Tres de Marco-511, 18085-180, Sorocaba, SP (Brazil)

    2009-05-01

    This work was performed to verify the chemical structure, mechanical and hydrophilic properties of amorphous hydrogenated carbon films prepared by plasma enhanced chemical vapor deposition, using acetylene/argon mixture as monomer. Films were prepared in a cylindrical quartz reactor, fed by 13.56 MHz radiofrequency. The films were grown during 5 min, for power varying from 25 to 125 W at a fixed pressure of 9.5 Pa. After deposition, all samples were treated by SF{sub 6} plasma with the aim of changing their hydrophilic character. Film chemical structure investigated by Raman spectroscopy, revealed the increase of sp{sup 3} hybridized carbon bonds as the plasma power increases. Hardness measurements performed by the nanoindentation technique showed an improvement from 5 GPa to 14 GPa following the increase discharge power. The untreated films presented a hydrophilic character, which slightly diminished after SF{sub 6} plasma treatment.

  4. Plasma-treated polyethylene film: A smart material applied for Salmonella Typhimurium detection

    Energy Technology Data Exchange (ETDEWEB)

    Peng-Ubol, Triranat [Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Rd, Phayathai, Bangkok 10400 (Thailand); Phinyocheep, Pranee, E-mail: scppo@mahidol.ac.th [Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Rd, Phayathai, Bangkok 10400 (Thailand); Daniel, Philippe [Laboratoire de Physique de l' Etat Condense (LPEC-UMR CNRS 6087), Universite du Maine, Avenue Olivier Messiaen, 72085, Le Mans Cedex 9 (France); Panbangred, Watanalai [Department of Biotechnology and Mahidol University-Osaka University Collaborative Research Center for Bioscience and Biotechnology (MU-OU: CRC), Faculty of Science, Mahidol University, Rama 6 Rd, Phayathai, Bangkok 10400 (Thailand); Pilard, Jean-Francois [Unite de Chimie Organique Moleculaire et Macromoleculaire (UCO2M-UMR CNRS 6011), Universite du Maine, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Thouand, Gerald; Durand-Thouand, Marie-Jose [Genie des Procedes Environnement et Agroalimentaire (GEPEA UMR CNRS 6144), Departement Genie Biologique, IUT de la Roche/Yon, Universite de Nantes, 18 Bd G. Defferre, 85035 La Roche sur Yon (France)

    2012-12-01

    Salmonella is a major cause of foodborne illness worldwide and is not allowed to be present in any food in all countries. The purpose of this study is to develop a simple alternative method for the detection of Salmonella based on functionalized polyethylene (PE) surfaces. Salmonella Typhimurium was used as a model bacterium. PE film was treated using dielectric plasma in order to alter the wettability of the PE surface and consequently introduce functionality on the surface. The PE film characterized by ATR-FTIR spectroscopy revealed the presence of C=O stretching of ketones, aldehydes and carboxylic acids. The antibodies against O or H antigens of Salmonella and S. Typhimurium were then respectively immobilized on the PE surface after activation of the carboxylic group using NHS/EDC followed by protein A. The evidences from ATR-FTIR, scanning electron microscopy and optical microscopy showed the presence of S. Typhimurium attached to the plasma treated PE surfaces via the two types of anti-Salmonella antibody. The plasma treated PE film developed is simple and allows efficient association of bacterial cells on the treated surfaces without the necessity of time-consuming centrifugation and washing steps for isolation of the cells. This material is considered to be a smart material applicable for S. Typhimurium detection. Highlights: Black-Right-Pointing-Pointer We developed a functionalized polyethylene film for bacterial detection. Black-Right-Pointing-Pointer We modified the surface of polyethylene film by plasma treatment. Black-Right-Pointing-Pointer ATR-FTIR spectroscopy was used to analyze the functionality on the PE surface. Black-Right-Pointing-Pointer We introduced Salmonella Typhimurium on the modified PE film. Black-Right-Pointing-Pointer SEM revealed the presence of S. Typhimurium on the plasma treated PE film.

  5. Plasma-treated polyethylene film: A smart material applied for Salmonella Typhimurium detection

    International Nuclear Information System (INIS)

    Peng-Ubol, Triranat; Phinyocheep, Pranee; Daniel, Philippe; Panbangred, Watanalai; Pilard, Jean-François; Thouand, Gerald; Durand-Thouand, Marie-José

    2012-01-01

    Salmonella is a major cause of foodborne illness worldwide and is not allowed to be present in any food in all countries. The purpose of this study is to develop a simple alternative method for the detection of Salmonella based on functionalized polyethylene (PE) surfaces. Salmonella Typhimurium was used as a model bacterium. PE film was treated using dielectric plasma in order to alter the wettability of the PE surface and consequently introduce functionality on the surface. The PE film characterized by ATR-FTIR spectroscopy revealed the presence of C=O stretching of ketones, aldehydes and carboxylic acids. The antibodies against O or H antigens of Salmonella and S. Typhimurium were then respectively immobilized on the PE surface after activation of the carboxylic group using NHS/EDC followed by protein A. The evidences from ATR-FTIR, scanning electron microscopy and optical microscopy showed the presence of S. Typhimurium attached to the plasma treated PE surfaces via the two types of anti-Salmonella antibody. The plasma treated PE film developed is simple and allows efficient association of bacterial cells on the treated surfaces without the necessity of time-consuming centrifugation and washing steps for isolation of the cells. This material is considered to be a smart material applicable for S. Typhimurium detection. Highlights: ► We developed a functionalized polyethylene film for bacterial detection. ► We modified the surface of polyethylene film by plasma treatment. ► ATR-FTIR spectroscopy was used to analyze the functionality on the PE surface. ► We introduced Salmonella Typhimurium on the modified PE film. ► SEM revealed the presence of S. Typhimurium on the plasma treated PE film.

  6. Effect of electronic contribution on temperature-dependent thermal transport of antimony telluride thin film

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won-Yong; Park, No-Won [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Hong, Ji-Eun [Department of Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Yoon, Soon-Gil, E-mail: sgyoon@cnu.ac.kr [Department of Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Koh, Jung-Hyuk [School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Lee, Sang-Kwon, E-mail: sangkwonlee@cau.ac.kr [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

    2015-01-25

    Highlights: • We investigated thermal transport of the antimony telluride thin films. • The contribution of the electronic thermal conductivity increased up to ∼77% at 300 K. • We theoretically analyze and explain the high contribution of electronic component. - Abstract: We study the theoretical and experimental characteristics of thermal transport of 100 nm and 500 nm-thick antimony telluride (Sb{sub 2}Te{sub 3}) thin films prepared by radio frequency magnetron sputtering. The thermal conductivity was measured at temperatures ranging from 20 to 300 K, using four-point-probe 3-ω method. Out-of-plane thermal conductivity of the Sb{sub 2}Te{sub 3} thin film was much lesser in comparison to the bulk material in the entire temperature range, confirming that the phonon- and electron-boundary scattering are enhanced in thin films. Moreover, we found that the contribution of the electronic thermal conductivity (κ{sub e}) in total thermal conductivity (κ) linearly increased up to ∼77% at 300 K with increasing temperature. We theoretically analyze and explain the high contribution of electronic component of thermal conductivity towards the total thermal conductivity of the film by a modified Callaway model. Further, we find the theoretical model predictions to correspond well with the experimental results.

  7. Thickness dependent ferromagnetism in thermally decomposed NiO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ravikumar, Patta; Kisan, Bhagaban; Perumal, Alagarsamy, E-mail: perumal@iitg.ernet.in

    2016-11-15

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

  8. A Sandwiched/Cracked Flexible Film for Multi-Thermal Monitoring and Switching Devices

    KAUST Repository

    Tai, Yanlong; Chen, Tao; Lubineau, Gilles

    2017-01-01

    Polydimethylsiloxane (PDMS)-based flexible films have substantiated advantages in various sensing applications. Here, we demonstrate the highly sensitive and programmable thermal-sensing capability (thermal index, B, up to 126 × 103 K) of flexible films with tunable sandwiched microstructures (PDMS/cracked single-walled carbon nanotube (SWCNT) film/PDMS) when a thermal stimulus is applied. We found that this excellent performance results from the following features of the film's structural and material design: (1) the sandwiched structure allows the film to switch from a three-dimensional to a two-dimensional in-plane deformation and (2) the stiffness of the SWCNT film is decreased by introducing microcracks that make deformation easy and that promote the macroscopic piezoresistive behavior of SWCNT crack islands and the microscopic piezoresistive behavior of SWCNT bundles. The PDMS layer is characterized by a high coefficient of thermal expansion (α = 310 × 10-6 K-1) and low stiffness (∼2 MPa) that allow for greater flexibility and higher temperature sensitivity. We determined the efficacy of our sandwiched, cracked, flexible films in monitoring and switching flexible devices when subjected to various stimuli, including thermal conduction, thermal radiation, and light radiation.

  9. Effect of magnetic field on the growth of Be films prepared by thermal evaporation

    International Nuclear Information System (INIS)

    Li, Kai; Luo, Bing-chi; Tan, Xiu-lan; Zhang, Ji-qiang; Wu, Wei-dong; Liu, Ying

    2014-01-01

    Highlights: • The Be films were prepared on Si (1 0 0) substrates with and without a magnetic field by thermal evaporation, respectively. • The grain diameter in the Be film transited from 300 nm to 18 nm by application of the magnetic field. • The surface roughness of the Be film decreased from 61 nm to 3 nm by application of the magnetic field. • The Be film grown with the magnetic field was easily oxidized due to its refined grains and the oxidation was gradually decreased with increasing the etching depth in the film. - Abstract: Grain refinement of beryllium deposits is studied as a significant subject for beryllium capsule in the Inertial Confinement Fusion project. The Be films were prepared on the Si (1 0 0) substrates by thermal evaporation with and without a magnetic field, respectively. The two separate groups of prepared Be films were characterized. The results showed the grain diameter in the Be film transited from 300 nm to 18 nm and the surface roughness of the Be film decreased from 61 nm to 3 nm by application of the magnetic field during the deposition process of Be coating. However, the Be film grown with the magnetic field was easily oxidized in comparison with that grown without magnetic field due to the refined grains, and the oxidation was gradually decreased with the increase of etching depth in the Be film. The reason for grain refinement of Be film was also qualitatively described

  10. Surface and sub-surface thermal oxidation of thin ruthenium films

    Energy Technology Data Exchange (ETDEWEB)

    Coloma Ribera, R.; Kruijs, R. W. E. van de; Yakshin, A. E.; Bijkerk, F. [MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Kokke, S.; Zoethout, E. [FOM Dutch Institute for Fundamental Energy Research (DIFFER), P.O. Box 1207, 3430 BE Nieuwegein (Netherlands)

    2014-09-29

    A mixed 2D (film) and 3D (nano-column) growth of ruthenium oxide has been experimentally observed for thermally oxidized polycrystalline ruthenium thin films. Furthermore, in situ x-ray reflectivity upon annealing allowed the detection of 2D film growth as two separate layers consisting of low density and high density oxides. Nano-columns grow at the surface of the low density oxide layer, with the growth rate being limited by diffusion of ruthenium through the formed oxide film. Simultaneously, with the growth of the columns, sub-surface high density oxide continues to grow limited by diffusion of oxygen or ruthenium through the oxide film.

  11. Stress in film/substrate system due to diffusion and thermal misfit effects

    International Nuclear Information System (INIS)

    Shao Shanshan; Xuan Fuzhen; Wang Zhengdong; Tu Shantung

    2009-01-01

    The stress in film/substrate systems has been analysed taking into consideration the coupling effects of diffusion and thermal misfit within the framework of Fick's second law. The solution of diffusion-induced stress in a film/substrate system involving the thermal misfit stress feedback is developed. The effects of modulus ratios, diffusivity ratios, thickness ratios of the substrate and the film and the partial molar volume of the diffusing component on the stress distribution in the film/substrate system are then discussed with the help of the finite difference method. Results indicate that the stresses in the film/substrate system vary with diffusion time. Diffusion enhances the magnitudes of film stress when the thermal misfit stress is compressive in the film. Furthermore, the absolute values of stress in the film increase with the increasing modulus ratios of the substrate and film, while they reduce with the increasing partial molar volume of the diffusing component and the diffusivity ratio of the substrate and the film.

  12. Effects of thermal treatment on the anodic growth of tungsten oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Y., E-mail: yqchai85@gmail.com; Tam, C.W.; Beh, K.P.; Yam, F.K.; Hassan, Z.

    2015-08-03

    This work reports the investigation of the effects of thermal treatment on anodic growth tungsten oxide (WO{sub 3}). The increase of the thermal treatment temperature above 400 °C significantly influences WO{sub 3} film where high porosity structure reduces to more compact film. As-grown film is amorphous, which transforms to monoclinic/orthorhombic phase upon annealing at 300–600 °C. With the reducing of porous structure, preferential growth of (002) plane shifts to (020) plane at 600 °C with more than twentyfold increase of peak's intensity compared to the film annealed at 500 °C. Films annealed at low thermal treatment show better ion intercalation and reversibility during electrochemical measurements; however, it has larger optical band gap. Photoelectrochemical measurement reveals that film annealed at 400 °C exhibits the best photocatalytic performance among the films annealed at 300–600 °C. - Highlights: • Porosity of the WO{sub 3} reduces as annealing temperature increases above 400 °C. • As-grown film is amorphous which transforms to monoclinic/orthorhombic upon annealing. • As-grown film shows better ion intercalation in electrochemical process. • Optical band gap of WO{sub 3} reduces as the annealing temperature increases. • Film annealed at 400 °C exhibits best photocatalytic performance.

  13. Microstructural, thermal and antibacterial properties of electron beam irradiated Bombyx mori silk fibroin films

    Energy Technology Data Exchange (ETDEWEB)

    Asha, S.; Sanjeev, Ganesh, E-mail: ganeshsanjeev@rediffmail.com [Microtron Center, Department of Studies in Physics, Mangalore University, Mangalagangotri - 574199 (India); Sangappa [Department of Studies in Physics, Mangalore University, Mangalagangotri - 574199 (India); Naik, Prashantha; Chandra, K. Sharat [Department of Biosciences, Mangalore University, Mangalagangotri - 574199 (India)

    2014-04-24

    The Bombyx mori silk fibroin (SF) films were prepared by solution casting method and the effects of electron beam on structural, thermal and antibacterial responses of the prepared films were studied. The electron irradiation for different doses was carried out using 8 MeV Microtron facility at Mangalore University. The changes in microstructural parameters and thermal stability of the films were investigated using Wide Angle X-ray Scattering (WAXS) and thermogravimetric analysis (TGA) respectively. Both microstructuralline parameters (crystallite size and lattice strain (g in %)) and thermal stability of the irradiated films have increased with radiation dosage. Agar diffusion method demonstrated the antibacterial activity of SF film which was increased after irradiation on both Gram-positive and Gram-negative species.

  14. Preparation and property of UV-curable polyurethane acrylate film filled with cationic surfactant treated graphene

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jinghong; Cai, Xia; Shen, Fenglei, E-mail: shenfenglei@suda.edu.cn

    2016-08-30

    Highlights: • The non-covalent modification of graphene maintains the intrinsic structure of graphene compared with the covalent functionalization of graphene. • The initial degradation temperature of nanocomposite film increases by 57 °C which is much higher than that of PUA nanocomposite previously reported. • The nanocomposite film exhibits improved dielectric property and electrical conductivity. • The outstanding performance of CTAB-G/PUA films will open up enormous opportunities for applications in various regions such as high temperature or electrical field. - Abstract: The preparation of nanocomposite films composed of UV-curable polyurethane acrylate (PUA) and modified graphene were demonstrated in this paper. Cetyl trimethyl ammonium bromide modified graphene (CTAB-G) was prepared via intercalation of cationic surfactant and subsequently incorporated into PUA by UV curing technology. Fourier transform infrared spectra, wide-angle X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to characterize the structure and morphology of CTAB-G, as well as CTAB-G/PUA nanocomposite films. The results revealed that the CTAB-G sheets were layer-by-layer structure and dispersed uniformly in PUA matrix. Thermal gravimetric analysis showed that the thermal stabilities of UV-curable PUA nanocomposite films in this work were much higher than that of PUA nanocomposites previously reported. Dynamic mechanical analysis indicated that the dynamic mechanical properties of nanocomposite films were greatly enhanced in the presence of modified graphene sheets. In addition, the CTAB-G/PUA nanocomposite films exhibited improved dielectric properties and electrical conductivities compared with the pure PUA.

  15. Swelling behavior of several bituminous coals and their thermally treated coals

    Energy Technology Data Exchange (ETDEWEB)

    Shui, Heng-fu; Cao, Mei-xia; Wang, Zhi-cai [Anhui University of Technology, Maanshan (China). School of Chemistry & Chemical Engineering

    2007-07-01

    The swelling behavior in different solvents of 4 bituminous coals with different ranks and their residues from extraction by CS{sub 2}/NMP mixed solvent (l:1 in volume) were measured. The change in swelling property of the four coals thermally treated at different temperature was observed. The results show that the swelling ratio decreases with increasing rank of coal. For lower rank bituminous coals the swelling ratios in polar solvent are higher than those in non-polar solvent, and this difference decreases with increasing rank. The cross-linking densities of the four residues decrease, and the swelling ratios increase compared with those of raw coals. The swelling ratios of the four thermally treated coals under 150{sup o}C in CS{sub 2} increase, suggesting the decrease in crosslinking density of them. When the thermal treatment temperature increases to 240{sup o}C, the swelling rations of the other three coals in NMP and CS{sub 2} increase again except gas coal, demonstrating the further decrease in crosslinking density. This result is coincident with the extraction yield change in the mixed solvent of the thermally treated coal. For example, the extraction yield of lean coal treated at 240{sup o}C increases from 6.9% to 17.3%. FT-IR results show the removal of oxygen group of the thermally treated coals. This may explain the increase in swelling ratio and extraction yield in the mixed solvent of coal after thermal treatment. The cross-linking density of the thermally treated coal decreases because of the break of hydrogen bonds due to removal of C = 0 and -OH oxygen groups during the thermal treatment, resulting in the increases of swelling ratio and extraction yield in the mixed solvent of thermally treated coal compared with those of raw coal. 15 refs., 3 figs., 6 tabs.

  16. Physicochemical, mechanical and thermal properties of chitosan films with and without sorbitol.

    Science.gov (United States)

    Liu, Mei; Zhou, Yibin; Zhang, Yang; Yu, Chen; Cao, Shengnan

    2014-09-01

    The effect of sorbitol on the physicochemical, mechanical and thermal properties of chitosan films with different degrees of deacetylation (DD; i.e., DD85% and DD95%) was investigated. The thickness, moisture content (MC), water solubility (WS) and water-vapor permeability (WVP) of the films were evaluated. Sorbitol addition reduced MC, increased WS and significantly (psorbitol increased the strain and decreased stress for both DD films, but DD95% could sustain higher strain and DD85% could sustain higher stress. Thermogravimetrics analysis and differential scanning calorimetry showed that sorbitol elicited a lower degradation temperature for both films, and that DD95% films exhibited higher thermal stability than DD85% films. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Characterization of Physical and Thermal Properties of Biofield Treated Neopentyl Glycol

    OpenAIRE

    Trivedi , Mahendra Kumar; Tallapragada , Rama Mohan; Branton , Alice; Trivedi , Dahryn; Nayak , Gopal; Mishra , Rakesh; Jana , Snehasis

    2015-01-01

    International audience; Neopentyl glycol (NPG) has been extensively used as solid-solid phase change materials (PCMs) for thermal energy storage applications. The objective of the present study was to evaluate the impact of biofield treatment on physical, spectral and thermal properties of NPG. The study was performed in two groups (control and treated). The control group remained as untreated, and treatment group was subjected to Mr. Trivedi’s biofield treatment. The control and treated NPG ...

  18. Characterization of Physical and Thermal Properties of Biofield Treated Neopentyl Glycol

    OpenAIRE

    Trivedi, Dahryn; Trivedi, Mahendra Kumar; Branton, Alice; Nayak, Gopal

    2015-01-01

    Neopentyl glycol (NPG) has been extensively used as solid-solid phase change materials (PCMs) for thermal energy storage applications. The objective of the present study was to evaluate the impact of biofield treatment on physical, spectral and thermal properties of NPG. The study was performed in two groups (control and treated). The control group remained as untreated, and treatment group was subjected to Mr. Trivedi’s biofield treatment. The control and treated NPG were characterized by X-...

  19. Thermal conductivity of nitride films of Ti, Cr, and W deposited by reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Jagannadham, Kasichainula

    2015-01-01

    Nitride films of Ti, Cr, and W were deposited using reactive magnetron sputtering from metal targets in argon and nitrogen plasma. TiN films with (200) orientation were achieved on silicon (100) at the substrate temperature of 500 and 600 °C. The films were polycrystalline at lower temperature. An amorphous interface layer was observed between the TiN film and Si wafer deposited at 600 °C. TiN film deposited at 600 °C showed the nitrogen to Ti ratio to be near unity, but films deposited at lower temperature were nitrogen deficient. CrN film with (200) orientation and good stoichiometry was achieved at 600 °C on Si(111) wafer but the film deposited at 500 °C showed cubic CrN and hexagonal Cr 2 N phases with smaller grain size and amorphous back ground in the x-ray diffraction pattern. An amorphous interface layer was not observed in the cubic CrN film on Si(111) deposited at 600 °C. Nitride film of tungsten deposited at 600 °C on Si(100) wafer was nitrogen deficient, contained both cubic W 2 N and hexagonal WN phases with smaller grain size. Nitride films of tungsten deposited at 500 °C were nonstoichiometric and contained cubic W 2 N and unreacted W phases. There was no amorphous phase formed along the interface for the tungsten nitride film deposited at 600 °C on the Si wafer. Thermal conductivity and interface thermal conductance of all the nitride films of Ti, Cr, and W were determined by transient thermoreflectance technique. The thermal conductivity of the films as function of deposition temperature, microstructure, nitrogen stoichiometry and amorphous interaction layer at the interface was determined. Tungsten nitride film containing both cubic and hexagonal phases was found to exhibit much higher thermal conductivity and interface thermal conductance. The amorphous interface layer was found to reduce effective thermal conductivity of TiN and CrN films

  20. Ultrasound treated potato peel and sweet lime pomace based biopolymer film development.

    Science.gov (United States)

    Borah, Purba Prasad; Das, Pulak; Badwaik, Laxmikant S

    2017-05-01

    Treatment and management of food processing waste is a major challenge for food industry. Potato processing industry generates tremendous amount of peel and consider it as zero valued waste. Again, pomace generated after juice extraction from sweet lime pulp is considered as waste and not properly utilized. Whereas these waste could be utilized for the development of biodegradable packaging film to overcome environmental issues. Composite films were prepared with varying proportion of potato peel powder (PP) and sweet lime pomace (SLP) in the ratio of 0:1(A), 0.5:1(B), 1:1(C), 1:0.5(D), 1:0(E) with an ultrasound treatment of 45min, and 0:1(F), 0.5:1(G), 1:1(H), 1:0.5(I), 1:0(J) with an ultrasound treatment of 60min. Ultrasound was applied for 45 and 60min to film forming solutions to break down biopolymer particles small enough to form a film. All the films were analyzed for their barrier and mechanical properties. It was observed that increasing ultrasound treatment times gives better result in film properties and less PP content also gives better film properties, from these observations film G prepared with 0.5:1 (PP:SLP) showed better characteristics among all other films. Water vapor permeability, moisture absorption, water solubility, breakage strength and elongation capacity of G film were reported as 7.25×10 -9 g/Pahm, 12.88±0.348%, 38.92±0.702%, 242.01±3.074g and 7.61±0.824mm respectively. However, thermal decomposition for film G took place above 200°C. The film forming solution of selected G film, added with clove essential oil (1.5%) as an antimicrobial agent was wrapped on bread and stored it for 5days. The film was successful in lowering the weight loss, reducing the hardness and inhibition of surface microbial load from bread sample. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Oxidation phase growth diagram of vanadium oxides film fabricated by rapid thermal annealing

    Institute of Scientific and Technical Information of China (English)

    Tamura KOZO; Zheng-cao LI; Yu-quan WANG; Jie NI; Yin HU; Zheng-jun ZHANG

    2009-01-01

    Thermal evaporation deposited vanadium oxide films were annealed in air by rapid thermal annealing (RTP). By adjusting the annealing temperature and time, a series of vanadium oxide films with various oxidation phases and surface morphologies were fabricated, and an oxidation phase growth diagram was established. It was observed that different oxidation phases appear at a limited and continuous annealing condition range, and the morphologic changes are related to the oxidation process.

  2. Carbon Nanostructure of Kraft Lignin Thermally Treated at 500 to 1000 °C.

    Science.gov (United States)

    Zhang, Xuefeng; Yan, Qiangu; Leng, Weiqi; Li, Jinghao; Zhang, Jilei; Cai, Zhiyong; Hassan, El Barbary

    2017-08-21

    Kraft lignin (KL) was thermally treated at 500 to 1000 °C in an inert atmosphere. Carbon nanostructure parameters of thermally treated KL in terms of amorphous carbon fraction, aromaticity, and carbon nanocrystallites lateral size ( L a ), thickness ( L c ), and interlayer space ( d 002 ) were analyzed quantitatively using X-ray diffraction, Raman spectroscopy, and high-resolution transmission electron microscopy. Experimental results indicated that increasing temperature reduced amorphous carbon but increased aromaticity in thermally treated KL materials. The L c value of thermally treated KL materials averaged 0.85 nm and did not change with temperature. The d 002 value decreased from 3.56 Å at 500 °C to 3.49 Å at 1000 °C. The L a value increased from 0.7 to 1.4 nm as temperature increased from 500 to 1000 °C. A nanostructure model was proposed to describe thermally treated KL under 1000 °C. The thermal stability of heat treated KL increased with temperature rising from 500 to 800 °C.

  3. Nanoscale thermal-mechanical probe determination of 'softening transitions' in thin polymer films

    International Nuclear Information System (INIS)

    Zhou Jing; Berry, Brian; Douglas, Jack F; Karim, Alamgir; Snyder, Chad R; Soles, Christopher

    2008-01-01

    We report a quantitative study of the softening behavior of glassy polystyrene (PS) films at length scales on the order of 100 nm using nano-thermomechanometry (nano-TM), an emerging scanning probe technique in which a highly doped silicon atomic force microscopy (AFM) tip is resistively heated on the surface of a polymer film. The apparent 'softening temperature' T s of the film is found to depend on the logarithm of the square root of the thermal ramping rate R. This relation allows us to estimate a quasi-equilibrium (or zero rate) softening transition temperature T s0 by extrapolation. We observe marked shifts of T s0 with decreasing film thickness, but the nature of these shifts, and even their sign, depend strongly on both the thermal and mechanical properties of the supporting substrate. Finite element simulations suggest that thin PS films on rigid substrates with large thermal conductivities lead to increasing T s0 with decreasing film thickness, whereas softer, less thermally conductive substrates promote reductions in T s0 . Experimental observations on a range of substrates confirm this behavior and indicate a complicated interplay between the thermal and mechanical properties of the thin PS film and the substrate. This study directly points to relevant factors for quantitative measurements of thermophysical properties of materials at the nanoscale using this nano-TM based method.

  4. Residual stress change by thermal annealing in amorphous Sm-Fe-B thin films

    International Nuclear Information System (INIS)

    Na, S.M.; Suh, S.J.; Kim, H.J.; Lim, S.H.

    2002-01-01

    The change in the residual stress and its effect on mechanical bending and magnetic properties of sputtered amorphous Sm-Fe-B thin films are investigated as a function of annealing temperature. Two stress components of intrinsic compressive stress and tensile stress due to the difference of the thermal expansion coefficients between the substrate and thin film are used to explain the stress state in as-deposited thin films, and the annealing temperature dependence of residual stress, mechanical bending and magnetic properties

  5. 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.

  6. 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

  7. 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.

  8. Thermally Annealed Iron (Oxide) Thin Film on an Alumina Barrier Layer, by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Madaan, Nitesh; Kanyal, Supriya S.; Jensen, David S.; Vail, Michael A.; Dadson, Andrew; Engelhard, Mark H.; Linford, Matthew R.

    2013-09-06

    Herein we show characterization of an Fe thin film on Al_2O_3 after thermal annealing under H_2 using Al Ka X-rays. The XPS survey spectrum, narrow Fe 2p scan, and valence band regions are presented. The survey spectrum shows aluminum signals due to exposure of the underlying Al_2O_3 film during Fe nanoparticle formation.

  9. Thermal stability of sulfonated Poly(Ether Ether Ketone) films : on the role of Protodesulfonation

    NARCIS (Netherlands)

    Koziara, B.T.; Kappert, E.J.; Ogieglo, W.; Nijmeijer, Kitty; Hempenius, M.A.; Benes, N.E.

    Thin film and bulk, sulfonated poly(ether ether ketone) (SPEEK) have been subjected to a thermal treatment at 160–250 °C for up to 15 h. Exposing the films to 160 °C already causes partial desulfonation, and heating to temperatures exceeding 200 °C results in increased conjugation in the material,

  10. Physicochemical Characterization of a Heat Treated Calcium Alginate Dry Film Prepared with Chicken Stock.

    Science.gov (United States)

    Báez, Germán D; Piccirilli, Gisela N; Ballerini, Griselda A; Frattini, Agustín; Busti, Pablo A; Verdini, Roxana A; Delorenzi, Néstor J

    2017-04-01

    Solid sodium alginate was dissolved into chicken stock in order to give a final alginate concentration of 0.9 percent (w/v). Calcium ions present in chicken stock were enough to induce ionic gelation. After drying, Fourier transform infrared spectroscopy, thickness and mechanical properties of films obtained were determined. Calcium alginate-chicken stock films were heated at 130 °C for different times between 0 and 15 min. Mechanical and optical studies, differential scanning calorimetry, visual aspect and scanning electron microscopy were carried out to describe physicochemical properties of heat treated films. Heating developed a maroon ochre color and increased the brittleness (crispness) of the films related to the intensity of the treatment. Differential scanning thermometry and study on appearance of the films suggested that Maillard reactions may be responsible for the observed changes. Maillard reactions mainly occurred between reducing sugar monomers and free amino groups of gelatin peptides present in the chicken stock, and between alginate and gelatin peptides to a lesser extent. In addition, the plasticizing effect of fat added with chicken stock was also studied. These studies suggest a potential use of heat treated chicken stock films as a substitute of roasted chicken skin. © 2017 Institute of Food Technologists®.

  11. Stress hysteresis during thermal cycling of plasma-enhanced chemical vapor deposited silicon oxide films

    Science.gov (United States)

    Thurn, Jeremy; Cook, Robert F.

    2002-02-01

    The mechanical response of plasma-enhanced chemical vapor deposited SiO2 to thermal cycling is examined by substrate curvature measurement and depth-sensing indentation. Film properties of deposition stress and stress hysteresis that accompanied thermal cycling are elucidated, as well as modulus, hardness, and coefficient of thermal expansion. Thermal cycling is shown to result in major plastic deformation of the film and a switch from a compressive to a tensile state of stress; both athermal and thermal components of the net stress alter in different ways during cycling. A mechanism of hydrogen incorporation and release from as-deposited silanol groups is proposed that accounts for the change in film properties and state of stress.

  12. Thermal analysis of continuous and patterned multilayer films in the presence of a nanoscale hot spot

    Science.gov (United States)

    Juang, Jia-Yang; Zheng, Jinglin

    2016-10-01

    Thermal responses of multilayer films play essential roles in state-of-the-art electronic systems, such as photo/micro-electronic devices, data storage systems, and silicon-on-insulator transistors. In this paper, we focus on the thermal aspects of multilayer films in the presence of a nanoscale hot spot induced by near field laser heating. The problem is set up in the scenario of heat assisted magnetic recording (HAMR), the next-generation technology to overcome the data storage density limit imposed by superparamagnetism. We characterized thermal responses of both continuous and patterned multilayer media films using transient thermal modeling. We observed that material configurations, in particular, the thermal barriers at the material layer interfaces crucially impact the temperature field hence play a key role in determining the hot spot geometry, transient response and power consumption. With a representative generic media model, we further explored the possibility of optimizing thermal performances by designing layers of heat sink and thermal barrier. The modeling approach demonstrates an effective way to characterize thermal behaviors of micro and nano-scale electronic devices with multilayer thin film structures. The insights into the thermal transport scheme will be critical for design and operations of such electronic devices.

  13. {sup 99}Mo sorption by thermally treated hydrotalcites

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, J.; Bertin, V.; Bulbulian, S.

    2000-04-04

    MoO{sub 4}{sup {minus}2} ions were sorbed in calcined hydrotalcite contained in a column. It was found that 98% of {sup 99m}Tc formed by {sup 99}Mo decay was eluted through the column in the form of pertechnetate. The content of radionuclides was determined by {gamma}-spectrometry, and natural molybdenum was measured by neutron activation analysis. Solids were characterized by thermal analysis, X-ray diffraction, and infrared spectroscopy. Through batch experiments, the hydrotalcite capacity toward molybdate ions (1.12 x 10{sup {minus}3} M) was found to be 3.2 mequiv g{sup {minus}1}. It was found that the high molybdate adsorbing capacity of calcined hydrotalcite could be utilized in designing a {sup 99m}Tc generator made with low specific activity {sup 99}Mo-molybdate samples.

  14. Sensitivity of thermally treated Bacillus subtilis spores to subsequent irradiation

    International Nuclear Information System (INIS)

    Mostafa, S.A.; El-Zawahry, Y.A.; Awny, N.M.

    1986-01-01

    B. subtilis spores exposed to thermal treatment at 70 or 80 0 C for 1 hr were more sensitive to subsequent radiation exposure than non-heated spores. Deactivation of previously heated spores by increasing dose of 0-radiation followed an exponential function while, for non-heated spores a shoulder followed by exponential deactivation was noticed. Combined heat-radiation treatment exhibited a synergistic effect on spore deactivation at low irradiation doses, while at high irradiation doses, the effect was more or less additive. Added values of spore injury was higher for B. subtilis spores that received heat and radiation separately than the observed injury for spores that received combined treatment (heat followed by radiation). Results of spore deactivation and injury due to heat followed by radiation treatment are discussed in comparison to those of spores that received radiation-heat sequence

  15. Thermal dewetting behavior of polystyrene composite thin films with organic-modified inorganic nanoparticles.

    Science.gov (United States)

    Kubo, Masaki; Takahashi, Yosuke; Fujii, Takeshi; Liu, Yang; Sugioka, Ken-ichi; Tsukada, Takao; Minami, Kimitaka; Adschiri, Tadafumi

    2014-07-29

    The thermal dewetting of polystyrene composite thin films with oleic acid-modified CeO2 nanoparticles prepared by the supercritical hydrothermal synthesis method was investigated, varying the nanoparticle concentration (0-30 wt %), film thickness (approximately 50 and 100 nm), and surface energy of silanized silicon substrates on which the composite films were coated. The dewetting behavior of the composite thin films during thermal annealing was observed by an optical microscope. The presence of nanoparticles in the films affected the morphology of dewetting holes, and moreover suppressed the dewetting itself when the concentration was relatively high. It was revealed that there was a critical value of the surface energy of the substrate at which the dewetting occurred. In addition, the spatial distributions of nanoparticles in the composite thin films before thermal annealing were investigated using AFM and TEM. As a result, we found that most of nanoparticles segregated to the surface of the film, and that such distributions of nanoparticles contribute to the stabilization of the films, by calculating the interfacial potential of the films with nanoparticles.

  16. 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.

  17. Physical vapor deposited films of a perylene derivative: supramolecular arrangement and thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Jose Diego; Alessio, Priscila; Silva, Matheus Rodrigues Medeiros; Aroca, Ricardo Flavio; Souza, Agda Eunice de; Constantino, Carlos Jose Leopoldo, E-mail: case@fct.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Presidente Prudente, SP (Brazil). Dept. de Fisica

    2017-07-15

    The analysis of supramolecular arrangement is essential to understand the role of this key factor on the optical and electrical properties of organic thin films. In this work, thin solid films of bis(phenethylimido) perylene (PhPTCD) fabricated using physical vapor deposition (PVD) technique (thermal evaporation), deposited simultaneously onto different substrates (Ag mirror, Ge, and quartz plates) contingent on the characterization technique. The main objective is to study the PhPTCD supramolecular arrangement and the thermal stability of this arrangement in PVD films. The ultraviolet-visible absorption reveals a controlled growth of the PVD films, and the micro-Raman scattering data show that the PhPTCD molecule is not thermally degraded in the conditions of these experiments. The microscopy also shows a homogeneous morphological surface of the PVD film at macro and micro scales, with molecular aggregates at nanoscale. Besides, the PVD film roughness does not follow substrate roughness. The X-ray diffraction indicates a crystalline structure for PhPTCD powder and an amorphous form for PhPTCD PVD film. The infrared absorption spectroscopy points to a preferential flat-on organization of the molecules in the PVD films. In addition, the annealing process (200 deg C for 20 minutes) does not affect the supramolecular arrangement of the PhPTCD PVD films. (author)

  18. Physical vapor deposited films of a perylene derivative: supramolecular arrangement and thermal stability

    International Nuclear Information System (INIS)

    Fernandes, Jose Diego; Alessio, Priscila; Silva, Matheus Rodrigues Medeiros; Aroca, Ricardo Flavio; Souza, Agda Eunice de; Constantino, Carlos Jose Leopoldo

    2017-01-01

    The analysis of supramolecular arrangement is essential to understand the role of this key factor on the optical and electrical properties of organic thin films. In this work, thin solid films of bis(phenethylimido) perylene (PhPTCD) fabricated using physical vapor deposition (PVD) technique (thermal evaporation), deposited simultaneously onto different substrates (Ag mirror, Ge, and quartz plates) contingent on the characterization technique. The main objective is to study the PhPTCD supramolecular arrangement and the thermal stability of this arrangement in PVD films. The ultraviolet-visible absorption reveals a controlled growth of the PVD films, and the micro-Raman scattering data show that the PhPTCD molecule is not thermally degraded in the conditions of these experiments. The microscopy also shows a homogeneous morphological surface of the PVD film at macro and micro scales, with molecular aggregates at nanoscale. Besides, the PVD film roughness does not follow substrate roughness. The X-ray diffraction indicates a crystalline structure for PhPTCD powder and an amorphous form for PhPTCD PVD film. The infrared absorption spectroscopy points to a preferential flat-on organization of the molecules in the PVD films. In addition, the annealing process (200 deg C for 20 minutes) does not affect the supramolecular arrangement of the PhPTCD PVD films. (author)

  19. 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.

  20. Enhanced high temperature thermoelectric response of sulphuric acid treated conducting polymer thin films

    KAUST Repository

    Sarath Kumar, S. R.; Kurra, Narendra; Alshareef, Husam N.

    2015-01-01

    We report the high temperature thermoelectric properties of solution processed pristine and sulphuric acid treated poly(3, 4-ethylenedioxythiophene):poly(4-styrenesulfonate) (or PEDOT:PSS) films. The acid treatment is shown to simultaneously enhance the electrical conductivity and Seebeck coefficient of the metal-like films, resulting in a five-fold increase in thermoelectric power factor (0.052 W/m. K ) at 460 K, compared to the pristine film. By using atomic force micrographs, Raman and impedance spectra and using a series heterogeneous model for electrical conductivity, we demonstrate that acid treatment results in the removal of PSS from the films, leading to the quenching of accumulated charge-induced energy barriers that prevent hopping conduction. The continuous removal of PSS with duration of acid treatment also alters the local band structure of PEDOT:PSS, resulting in simultaneous enhancement in Seebeck coefficient.

  1. Enhanced high temperature thermoelectric response of sulphuric acid treated conducting polymer thin films

    KAUST Repository

    Sarath Kumar, S. R.

    2015-11-24

    We report the high temperature thermoelectric properties of solution processed pristine and sulphuric acid treated poly(3, 4-ethylenedioxythiophene):poly(4-styrenesulfonate) (or PEDOT:PSS) films. The acid treatment is shown to simultaneously enhance the electrical conductivity and Seebeck coefficient of the metal-like films, resulting in a five-fold increase in thermoelectric power factor (0.052 W/m. K ) at 460 K, compared to the pristine film. By using atomic force micrographs, Raman and impedance spectra and using a series heterogeneous model for electrical conductivity, we demonstrate that acid treatment results in the removal of PSS from the films, leading to the quenching of accumulated charge-induced energy barriers that prevent hopping conduction. The continuous removal of PSS with duration of acid treatment also alters the local band structure of PEDOT:PSS, resulting in simultaneous enhancement in Seebeck coefficient.

  2. Acetylated rice starches films with different levels of amylose: Mechanical, water vapor barrier, thermal, and biodegradability properties.

    Science.gov (United States)

    Colussi, Rosana; Pinto, Vânia Zanella; El Halal, Shanise Lisie Mello; Biduski, Bárbara; Prietto, Luciana; Castilhos, Danilo Dufech; Zavareze, Elessandra da Rosa; Dias, Alvaro Renato Guerra

    2017-04-15

    Biodegradable films from native or acetylated starches with different amylose levels were prepared. The films were characterized according to the mechanical, water vapor barrier, thermal, and biodegradability properties. The films from acetylated high amylose starches had higher moisture content and water solubility than the native high amylose starch film. However, the acetylation did not affect acid solubility of the films, regardless of the amylose content. Films made from high and medium amylose rice starches were obtained; however low amylose rice starches, whether native or acetylated, did not form films with desirable characteristics. The acetylation decreased the tensile strength and increased the elongation of the films. The acetylated starch-based films had a lower decomposition temperature and higher thermal stability than native starch films. Acetylated starches films exhibited more rapid degradation as compared with the native starches films. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Morphology and thermal stability of Ti-doped copper nitride films

    International Nuclear Information System (INIS)

    Fan Xiaoyan; Wu Zhiguo; Li Huajun; Geng Baisong; Li Chun; Yan Pengxun

    2007-01-01

    A weakly Ti-doped copper nitride (Cu 3 N) film was prepared by cylindrical magnetron sputtering. The XPS results indicate that Ti atoms do not substitute for the Cu atoms but probably locate at the grain boundaries. The columnar grains size is about half of that of the undoped Cu 3 N film and the surface is smoother. For weakly Ti-doped Cu 3 N films, a dense layer appears on top of the columnar crystals. The RMS of the Cu film formed by annealing of the weakly Ti-doped Cu 3 N film is more than twice larger than that of the film before annealing. Compared with the undoped Cu 3 N film, it possesses fine thermal stability both in vacuum and in atmosphere

  4. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Borghi, F.; Lenardi, C.; Podestà, A.; Milani, P., E-mail: pmilani@mi.infn.it [CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Sogne, E. [CIMAINA and Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); European School of Molecular Medicine (SEMM), IFOM-IEO, Milano (Italy); Merlini, M. [Dipartimento di Scienze della Terra “Ardito Desio”, Università degli Studi di Milano, via Mangiagalli 32, 20133 Milano (Italy); Ducati, C. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

    2016-08-07

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments.

  5. Thermal expansion coefficient measurement from electron diffraction of amorphous films in a TEM.

    Science.gov (United States)

    Hayashida, Misa; Cui, Kai; Malac, Marek; Egerton, Ray

    2018-05-01

    We measured the linear thermal expansion coefficients of amorphous 5-30 nm thick SiN and 17 nm thick Formvar/Carbon (F/C) films using electron diffraction in a transmission electron microscope. Positive thermal expansion coefficient (TEC) was observed in SiN but negative coefficients in the F/C films. In case of amorphous carbon (aC) films, we could not measure TEC because the diffraction radii required several hours to stabilize at a fixed temperature. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

  6. Determination of the mechanical, diffractometer and thermal properties of chitosan and hydroxypropyl methylcellulose films (HPMC)

    International Nuclear Information System (INIS)

    Rotta, Jefferson; Minatti, Edson; Barreto, Pedro L.M.

    2009-01-01

    This work examined the mechanical, diffractometry and thermal properties of chitosan-hydroxypropyl methylcellulose (HPMC) films. The solutions of chitosan and hydroxypropyl methylcellulose were mixed at different proportions (100/0; 70/30; 50/50; 30/70 and 0/100) respectively, and 20 m L was casting at Petri dishes to posterior analysis of dried films. The miscibility of polymers has been assessed by X-ray diffraction, differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). It was shown that although weak hydrogen bonding exists between the polymer functional groups, the films are not fully miscible at a dry state. (author)

  7. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    International Nuclear Information System (INIS)

    Borghi, F.; Lenardi, C.; Podestà, A.; Milani, P.; Sogne, E.; Merlini, M.; Ducati, C.

    2016-01-01

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments.

  8. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    KAUST Repository

    Borghi, F.; Sogne, Elisa; Lenardi, C.; Podestà , A.; Merlini, M.; Ducati, C.; Milani, P.

    2016-01-01

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments. Published by AIP Publishing.

  9. Structural and thermal properties of silk fibroin - Silver nanoparticles composite films

    Science.gov (United States)

    Shivananda, C. S.; Rao B, B. Lakshmeesha; Shetty, G. Rajesh; Sangappa, Y.

    2018-05-01

    In this work, silk fibroin-silver nanoparticles (SF-AgNPs) composite films have been prepared by simple solution casting method. The composite films were examined for structural and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results showed that with the introduction of AgNPs in the silk fibroin matrix the amorphous nature of the silk fibroin decreases with increasing nanoparticles concentration. The silk fibroin films possess good thermal stability with the presence of AgNPs.

  10. Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

    KAUST Repository

    Borghi, F.

    2016-08-05

    Nanostructured zirconium dioxide (zirconia) films are very promising for catalysis and biotechnological applications: a precise control of the interfacial properties of the material at different length scales and, in particular, at the nanoscale, is therefore necessary. Here, we present the characterization of cluster-assembled zirconia films produced by supersonic cluster beam deposition possessing cubic structure at room temperature and controlled nanoscale morphology. We characterized the effect of thermal annealing in reducing and oxidizing conditions on the crystalline structure, grain dimensions, and topography. We highlight the mechanisms of film growth and phase transitions, which determine the observed interfacial morphological properties and their resilience against thermal treatments. Published by AIP Publishing.

  11. 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.

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

    International Nuclear Information System (INIS)

    Tripathy, Sumanta K.; Rajeswari, V. P.

    2014-01-01

    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 3 O 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

  13. Structural, Thermal, Physical, Mechanical, and Barrier Properties of Chitosan Films with the Addition of Xanthan Gum.

    Science.gov (United States)

    de Morais Lima, Maria; Carneiro, Lucia Cesar; Bianchini, Daniela; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa; Prentice, Carlos; Moreira, Angelita da Silveira

    2017-03-01

    Films based on chitosan and xanthan gum were prepared using casting technique aiming to investigate the potential of these polymers as packaging materials. Six formulations of films were studied varying the proportion of chitosan and xanthan gum: 100:0 (chitosan:xanthan gum, w/w, C100XG0 film); 90:10 (chitosan:xanthan gum, w/w, C90XG10 film); 80:20 (chitosan:xanthan gum, w/w, C80XG20 film); 70:30 (chitosan:xanthan gum, w/w, C70XG30 film); 60:40 (chitosan:xanthan gum, w/w, C60XG40 film); and 50:50 (chitosan:xanthan gum, w/w, C50XG50 film). The total quantity of solids (chitosan and xanthan gum) in the filmogenic solution was 1.5 g per 100 mL of aqueous solution for all treatments, according to the proportion of each polymer. The films were evaluated by their functional groups, structural, thermal, morphological, physical, mechanical, and barrier properties. All films have presented endothermic peaks in the range of 122 to 175 °C and broad exothermic peaks above 200 °C, which were assigned to the melting temperature and thermal decomposition, respectively. These results demonstrated that films with xanthan gum have the highest T m and Δ m H. The films containing higher content of xanthan gum show also the highest tensile strength and the lowest elongation. Xanthan gum addition did not affect the water vapor permeability, solubility, and moisture of films. This set of data suggests the formation of chitosan-xanthan complexes in the films. © 2017 Institute of Food Technologists®.

  14. Thermal analysis of used and radiation treated polycarbonate (L-MW) biomaterial

    International Nuclear Information System (INIS)

    Jayabalan, M.; Sreenivasan, K.; Nair, P.D.; Jalajamani, K.V.

    1988-01-01

    γ-radiation treatment of radiation sterilized polycarbonate biomaterials has been carried out to ensure efficient disposal by incineration. Low molecular weight polycarbonate sterilized with 2.5 Mrad dose of γ-radiation was further treated with different doses of γ-radiation. The radiation-treated samples were subjected to thermogravimetry. The sterilized sample and the 7.5 Mrad-treated sample showed similar properties. These samples do not leave any residue during thermal decomposition. (author). 5 refs., 3 tables

  15. Evolution of free volume in ultrasoft magnetic FeZrN films during thermal annealing

    NARCIS (Netherlands)

    Chechenin, NG; van Veen, A; Schut, H; Chezan, AR; Boerma, DO; Vystavel, T; De Hosson, JTM; DeHaven, PW; Field, DP; Harkness, SD; Sutliff, JA; Szpunar, JA; Tang, L; Thomson, T; Vaudin, MD

    2002-01-01

    The thermal stability of nanocrystalline ultra-soft magnetic (Fe98Zr2)(1-x)N-x films with x=0.10-0.25 was studied using high-resolution transmission electron microscopy (HRTEM), positron beam analysis (PBA) and thermal desorption spectrometry (TDS). The results demonstrate that grain growth during

  16. Decomposition of thin titanium deuteride films: thermal desorption kinetics studies combined with microstructure analysis

    NARCIS (Netherlands)

    Lisowski, W.F.; Keim, Enrico G.; Kaszkur, Zbigniew; Smithers, M.A.; Smithers, Mark A.

    2008-01-01

    The thermal evolution of deuterium from thin titanium films, prepared under UHV conditions and deuterated in situ at room temperature, has been studied by means of thermal desorption mass spectrometry (TDMS) and a combination of scanning electron microscopy (SEM), transmission electron microscopy

  17. Microstructural modifications induced by rapid thermal annealing in plasma deposited SiOxNyHz films

    International Nuclear Information System (INIS)

    Prado, A. del; San Andres, E.; Martil, I.; Gonzalez-Diaz, G.; Bravo, D.; Lopez, F.J.; Fernandez, M.; Martinez, F.L.

    2003-01-01

    The effect of rapid thermal annealing (RTA) processes on the structural properties of SiO x N y H z films was investigated. The samples were deposited by the electron cyclotron resonance plasma method, using SiH 4 , O 2 and N 2 as precursor gases. For SiO x N y H z films with composition close to that of SiO 2 , which have a very low H content, RTA induces thermal relaxation of the lattice and improvement of the structural order. For films of intermediate composition and of compositions close to SiN y H z , the main effect of RTA is the release of H at high temperatures (T>700 deg. C). This H release is more significant in films containing both Si-H and N-H bonds, due to cooperative reactions between both kinds of bonds. In these films the degradation of structural order associated to H release prevails over thermal relaxation, while in those films with only N-H bonds, thermal relaxation predominates. For annealing temperatures in the 500-700 deg. C range, the passivation of dangling bonds by the nonbonded H in the films and the transition from the paramagnetic state to the diamagnetic state of the K center result in a decrease of the density of paramagnetic defects. The H release observed at high annealing temperatures is accompanied by an increase of density of paramagnetic defects

  18. Thermal degradation of ternary blend films containing PVA/chitosan/vanillin

    Science.gov (United States)

    Kasai, Deepak; Chougale, Ravindra; Masti, Saraswati; Narasgoudar, Shivayogi

    2018-05-01

    The ternary chitosan/poly (vinyl alcohol)/vanillin blend films were prepared by solution casting method. The influence of equal weight percent of poly (vinyl alcohol) and vanillin on thermal stability of the chitosan blend films were investigated by using thermogravimetric analysis (TGA). The kinetic parameters such as enthalpy (ΔH*), entropy (ΔS*), and Gibbs free energy (ΔG*) in the first and second decomposition steps based on the thermogravimetric data were calculated. The thermal stabilities of the blend films were confirmed by thermodynamic parameters obtained in the activation energies, which indicated that increase in the equal weight percent of PVA/vanillin decreased the thermal stability of the chitosan film.

  19. Significant Enhancement of Thermal Conductivity in Nanofibrillated Cellulose Films with Low Mass Fraction of Nanodiamond.

    Science.gov (United States)

    Song, Na; Cui, Siqi; Hou, Xingshuang; Ding, Peng; Shi, Liyi

    2017-11-22

    High thermal conductive nanofibrillated cellulose (NFC) hybrid films based on nanodiamond (ND) were fabricated by a facile vacuum filtration technique. In this issue, the thermal conductivity (TC) on the in-plane direction of the NFC/ND hybrid film had a significant enhancement of 775.2% at a comparatively low ND content (0.5 wt %). The NFC not only helps ND to disperse in the aqueous medium stably but also plays a positive role in the formation of the hierarchical structure. ND could form a thermal conductive pathway in the hierarchical structures under the intermolecular hydrogen bonds. Moreover, the hybrid films composed of zero-dimensional ND and one-dimensional NFC exhibit remarkable mechanical properties and optical transparency. The NFC/ND hybrid films possessing superior TC, mechanical properties, and optical transparency can open applications for portable electronic equipment as a lateral heat spreader.

  20. Chemical Vapor Identification by Plasma Treated Thick Film Tin Oxide Gas Sensor Array and Pattern Recognition

    Directory of Open Access Journals (Sweden)

    J. K. Srivastava

    2011-02-01

    Full Text Available Present study deals the class recognition potential of a four element plasma treated thick film tin oxide gas sensor array exposed with volatile organic compounds (VOCs. Methanol, Ethanol and Acetone are selected as target VOCs and exposed on sensor array at different concentration in range from 100-1000 ppm. Sensor array consist of four tin oxide sensors doped with 1-4 % PbO concentrations were fabricated by thick film technology and then treated with oxygen plasma for 5-10 minute durations. Sensor signal is analyzed by principal component analysis (PCA for visual classification of VOCs. Further output of PCA is used as input for classification of VOCs by four pattern classification techniques as: linear discriminant analysis (LDA, k-nearest neighbor (KNN, back propagation neural network (BPNN and support vector machine (SVM. All the four classifier results 100 % correct classification rate of VOCs by response analysis of sensor array treated with plasma for 5 minute.

  1. Interface thermal resistance of nanostructured FeCoCu film and Si substrate

    Science.gov (United States)

    Nikolaenko, Yuri M.; Medvedev, Yuri V.; Genenko, Yuri A.; Ghafari, Mohammad; Hahn, Horst

    2006-05-01

    Results of measurement of thermal resistance (RFS ) of film substrate interface of 10 nm (Fe1-x Cox )1-y Cuy film on Si substrate with 50 nm SiO2 sublayer are presented. The estimated magnitude is two orders greater then RFS of epitaxial manganite films on StTiO3 substrate with and without sublayer. The significant increase of RFS is explained by granular structure of film with average size of grain about 10 nm. In this case the additional thermal barier in the film-substrate interface is appeared. It provides the change of regime of phonons propagation from ballistic to diffusion one. The principle possibility of variation of RFS in wide range as a task of nanotechnology is discussed.

  2. Mechanical and thermal properties of irradiated films based on Tilapia (Oreochromis niloticus) proteins

    Energy Technology Data Exchange (ETDEWEB)

    Sabato, S.F. [Radiation Technology Center, IPEN-CNEN/SP, Av. Lineu Prestes 2242, 05508 900 Sao Paulo, SP (Brazil)], E-mail: sfsabato@ipen.br; Nakamurakare, N.; Sobral, P.J.A. [Food Engineering Department, ZEA/FZEA/USP, Av. Duque de Caxias Norte 225, 13635 900 Pirassununga, SP (Brazil)

    2007-11-15

    Proteins are considered potential material in natural films as alternative to traditional packaging. When gamma radiation is applied to protein film forming solution it resulted in an improvement in mechanical properties of whey protein films. The objective of this work was the characterization of mechanical and thermal properties of irradiated films based on muscle proteins from Nile Tilapia (Oreochromis niloticus). The films were prepared according to a casting technique with two levels of plasticizer: 25% and 45% glycerol and irradiated in electron accelerator type Radiation Dynamics, 0.550 MeV at dose range from 0 to 200 kGy. Thermal properties and mechanical properties were determined using a differential scanning calorimeter and a texture analyzer, respectively. Radiation from electron beam caused a slightly increase on its tensile strength characteristic at 100 kGy, while elongation value at this dose had no reduction.

  3. Mechanical and thermal properties of irradiated films based on Tilapia (Oreochromis niloticus) proteins

    International Nuclear Information System (INIS)

    Sabato, S.F.; Nakamurakare, N.; Sobral, P.J.A.

    2007-01-01

    Proteins are considered potential material in natural films as alternative to traditional packaging. When gamma radiation is applied to protein film forming solution it resulted in an improvement in mechanical properties of whey protein films. The objective of this work was the characterization of mechanical and thermal properties of irradiated films based on muscle proteins from Nile Tilapia (Oreochromis niloticus). The films were prepared according to a casting technique with two levels of plasticizer: 25% and 45% glycerol and irradiated in electron accelerator type Radiation Dynamics, 0.550 MeV at dose range from 0 to 200 kGy. Thermal properties and mechanical properties were determined using a differential scanning calorimeter and a texture analyzer, respectively. Radiation from electron beam caused a slightly increase on its tensile strength characteristic at 100 kGy, while elongation value at this dose had no reduction

  4. Thermal-treated soil for mercury removal: Soil and phytotoxicity tests

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Y.; Edwards, N.T.; Lee, S.Y.; Stiles, C.A.; Armes, S.; Foss, J.E.

    2000-04-01

    Mercury (Hg) contamination of soils and sediments is one of many environmental problems at the Oak Ridge Reservation, Oak Ridge, TN. Mercury-contaminated soil from the Lower East Fork Poplar Creek (LEFPC) at the Oak Ridge Reservation was treated thermally to reduce Hg concentration to a below target level (20 mg kg{sup {minus}1}) as a pilot scale thermal treatment demonstration. As a part of performance evaluation, the soil characteristics and plant growth response of the untreated and treated soil were examined. The soil treated at 350 C retained most of its original soil properties, but the soil treated at 600 C exhibited considerable changes in mineralogical composition and physicochemical characteristics. Growth and physiological response of the three plant species radish (Raphanus sativus L.), fescue (Festuca arundinacea Schreb.), and oat (Avena sativa L.) indicated adverse effects of the thermal treatment. The addition of N fertilizer had beneficial effects in the 350 C treated soil, but had little beneficial effect in the 600 C treated soil. Some changes of soil characteristics induced by thermal treatment cannot be avoided. Soil characteristics and phytotoxicity test results strongly suggest that changes occurring following the 350 C treatment do not limit the use of the treated soil to refill the excavated site for full-scale remediation. The only problem with the 350 C treatment is that small amounts of Hg compounds (<15 mg kg{sup {minus}1}) remain in the soil and a processing cost of $45/Mg.

  5. Fabrication of indium tin oxide (ITO) thin film with pre-treated sol coating

    International Nuclear Information System (INIS)

    Hong, Sung-Jei; Han, Jeong-In

    2004-01-01

    A new pre-treated sol-coating method to fabricate an indium tin oxide (ITO) thin film is introduced in this paper. The pre-treatment sol-coating method is to form a seed layer on the substrate before spin coating of ITO sol. The pre-treatment was carried out at room temperature in order not to damage the substrate during the pre-treatment. It is effective to enhance the formation of the ITO sol film on the substrate, owing to the seed layer. The seed layer consists of ultrafine grains, which are observed at the pre-treated substrate. For the optimal pre-treatment condition, we used pre-treatment times of 24, 48, 72, and 96 hours to observe the effect on the characteristics of ITO sol film. As a result, the lowest resistance could be achieved with a pre-treatment time of 72 hours. The optical transmittance of the ITO sol film with the pre-treatment time of 72 hours exceeded 80 % at a wavelength of 400 nm. So, an ITO sol film with good electrical and optical properties could be fabricated by using the pretreatment sol coating.

  6. Modification of mechanical and thermal property of chitosan–starch blend films

    International Nuclear Information System (INIS)

    Tuhin, Mohammad O.; Rahman, Nazia; Haque, M.E.; Khan, Ruhul A.; Dafader, N.C.; Islam, Rafiqul; Nurnabi, Mohammad; Tonny, Wafa

    2012-01-01

    Chitosan–starch blend films (thickness 0.2 mm) of different composition were prepared by casting and their mechanical properties were studied. To improve the properties of chitosan–starch films, glycerol and mustard oil of different composition were used. Chitosan–starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. The modified films showed improvement in both tensile strength and elongation at break than the pure chitosan–starch films. Water uptake of the films reduced significantly than the pure chitosan–starch film. Thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the modified films experience less thermal degradation than the pure films. Scanning electron microscopy (SEM) and FTIR were used to investigate the morphology and molecular interaction of the blend film, respectively. - Highlights: ► Chitosan–starch blend films (thickness 0.2 mm) were prepared by casting. ► To improve the properties of chitosan–starch films, glycerol and mustard oil of different composition were used. ► Chitosan–starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. ► Properties of the modified films such as tensile strength, elongation at break, water uptake, TGA, DMA, SEM, FTIR were studied. ► Results indicate that modification of chitosan–starch film with mustard oil improved the properties of the blend films which could be further modified by HEMA using gamma radiation.

  7. Effect of thickness on optical properties of thermally evaporated SnS films

    International Nuclear Information System (INIS)

    Selim, M.S.; Gouda, M.E.; El-Shaarawy, M.G.; Salem, A.M.; Abd El-Ghany, W.A.

    2013-01-01

    The effect of film thickness on the structure and optical properties of thermally evaporated SnS film has been studied. SnS films with different thicknesses in the range 152–585 nm were deposited onto clean glass substrates at room temperature. X-ray diffraction study revealed that SnS films of thickness ≥ 283 nm are crystalline, whereas films of lower thickness exhibit poor crystalline with more amorphous background. The crystalline nature of the lower film thickness has been confirmed using transmission electron microscope and the corresponding electron diffraction pattern. The thicker film samples showed nearly stoichiometric chemical composition; however, thinner samples are deficient in S and rich in Sn. The optical property of the deposited films has been investigated in the wavelength range 350–2500 nm. The refractive index increases notably with increasing film thickness. The refractive index for the investigated film thicknesses are adequately described by the effective-single-oscillator model. The static refractive index and the static dielectric constant have been calculated. Analysis of the optical absorption coefficient revealed the presence of direct optical transition and the corresponding band gap values were found to decrease as the film thickness increases. - Highlights: ► X-ray diffraction was used to study the structure of SnS films. ► Transmission electron microscope confirms the crystalline state of SnS films. ► The refractive index increases notably with increasing the film thickness. ► The optical band gap of SnS films decreases with increasing film thickness

  8. Structural, morphological and optical properties of thermal annealed TiO thin films

    International Nuclear Information System (INIS)

    Zribi, M.; Kanzari, M.; Rezig, B.

    2008-01-01

    Structural, morphological and optical properties of TiO thin films grown by single source thermal evaporation method were studied. The films were annealed from 300 to 520 deg. C in air after evaporation. Qualitative film analysis was performed with X-ray diffraction, atomic force microscopy and optical transmittance and reflectance spectra. A correlation was established between the optical properties, surface roughness and growth morphology of the evaporated TiO thin films. The X-ray diffraction spectra indicated the presence of the TiO 2 phase for the annealing temperature above 400 deg. C

  9. 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 ...

  10. Improved electrochemical performances of oxygen plasma treated LiMn2O4 thin films

    International Nuclear Information System (INIS)

    Chen, C C; Chiu, K-F; Lin, K M; Lin, H C; Yang, C-R; Wang, F M

    2007-01-01

    LiMn 2 O 4 spinel thin films were deposited by radio frequency (rf) magnetron sputtering followed by annealing at 600 0 C in air.The films were then post-treated with an rf driven oxygen plasma. The crystallization and surface morphology of LiMn 2 O 4 thin films were seen to change with rf power. The treated samples were tested under harsh conditions such as deep discharge to 1.5 V and cycling at elevated temperature of 60 0 C to verify the electrochemical performances of LiMn 2 O 4 cathodes. The oxygen plasma treatments improved the electrochemical properties of LiMn 2 O 4 thin films significantly. As the cells were cycled in the range of 4.5-2.0 V at 60 0 C, the samples treated at a proper rf power of 50 W exhibited an initial capacity greater than ∼400 mAh g -1 with reasonable cycling stability. The results were attributed to the change of morphology and the formation of a surface layer induced by the oxygen plasma irradiation

  11. 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)

  12. Study of thermal and mechanical properties of PCL films; Estudo das propriedades termicas de filmes a base de PCL

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, A.R. de; Vieira, A.B. da Silva; Leite, I.F., E-mail: itamaraf@gmail.com [Universidade Federal da Paraiba (UFPB), Joaoo Pessoa, PB (Brazil). Departamento de Engenharia de Materiais

    2016-07-01

    In the current situation of the market, it is remarkable the concern for the development of materials that offer better properties and biodegradable behavior. The scientific researches seeks development and improvement of materials for applications in products increasingly biodegradable. To do so, this research aims at obtaining films composed of polymer poly(ε-caprolactone)(PCL), aliphatic polyester synthetic and biodegradable, and silicates in layers, specifically in the State of Paraiba, prepared by the method of solution. This mixture makes it possible to form different nanostructures intercalated morphology and/or exfoliated, which therefore provides improvement in the thermal properties of the final product. After analyzing the results of X-ray diffraction (XRD) was observed predominantly exfoliated morphologies to PCL films containing different silicate content and an increase in thermal stability when there was a lower concentration of clay as thermal analysis (TGA). (author)

  13. Measurement of Thermal Properties of Triticale Starch Films Using Photothermal Techniques

    Science.gov (United States)

    Correa-Pacheco, Z. N.; Cruz-Orea, A.; Jiménez-Pérez, J. L.; Solorzano-Ojeda, S. C.; Tramón-Pregnan, C. L.

    2015-06-01

    Nowadays, several commercially biodegradable materials have been developed with mechanical properties similar to those of conventional petrochemical-based polymers. These materials are made from renewable sources such as starch, cellulose, corn, and molasses, being very attractive for numerous applications in the plastics, food, and paper industries, among others. Starches from maize, rice, wheat, and potato are used in the food industry. However, other types of starches are not used due to their low protein content, such as triticale. In this study, starch films, processed using a single screw extruder with different compositions, were thermally and structurally characterized. The thermal diffusivity, thermal effusivity, and thermal conductivity of the biodegradable films were determined using photothermal techniques. The thermal diffusivity was measured using the open photoacoustic cell technique, and the thermal effusivity was obtained by the photopyroelectric technique in an inverse configuration. The results showed differences in thermal properties for the films. Also, the films microstructures were observed by scanning electron microscopy, transmission electron microscopy, and the crystalline structure determined by X-ray diffraction.

  14. 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)

  15. Coplanar amorphous-indium-gallium-zinc-oxide thin film transistor with He plasma treated heavily doped layer

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Ho-young [Advanced Display Research Center, Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of); LG Display R and D Center, 245 Lg-ro, Wollong-myeon, Paju-si, Gyeonggi-do 413-811 (Korea, Republic of); Lee, Bok-young; Lee, Young-jang; Lee, Jung-il; Yang, Myoung-su; Kang, In-byeong [LG Display R and D Center, 245 Lg-ro, Wollong-myeon, Paju-si, Gyeonggi-do 413-811 (Korea, Republic of); Mativenga, Mallory; Jang, Jin, E-mail: jjang@khu.ac.kr [Advanced Display Research Center, Department of Information Display, Kyung Hee University, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of)

    2014-01-13

    We report thermally stable coplanar amorphous-indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) with heavily doped n{sup +} a-IGZO source/drain regions. Doping is through He plasma treatment in which the resistivity of the a-IGZO decreases from 2.98 Ω cm to 2.79 × 10{sup −3} Ω cm after treatment, and then it increases to 7.92 × 10{sup −2} Ω cm after annealing at 300 °C. From the analysis of X-ray photoelectron spectroscopy, the concentration of oxygen vacancies in He plasma treated n{sup +}a-IGZO does not change much after thermal annealing at 300 °C, indicating thermally stable n{sup +} a-IGZO, even for TFTs with channel length L = 4 μm. Field-effect mobility of the coplanar a-IGZO TFTs with He plasma treatment changes from 10.7 to 9.2 cm{sup 2}/V s after annealing at 300 °C, but the performance of the a-IGZO TFT with Ar or H{sub 2} plasma treatment degrades significantly after 300 °C annealing.

  16. Coplanar amorphous-indium-gallium-zinc-oxide thin film transistor with He plasma treated heavily doped layer

    International Nuclear Information System (INIS)

    Jeong, Ho-young; Lee, Bok-young; Lee, Young-jang; Lee, Jung-il; Yang, Myoung-su; Kang, In-byeong; Mativenga, Mallory; Jang, Jin

    2014-01-01

    We report thermally stable coplanar amorphous-indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs) with heavily doped n + a-IGZO source/drain regions. Doping is through He plasma treatment in which the resistivity of the a-IGZO decreases from 2.98 Ω cm to 2.79 × 10 −3 Ω cm after treatment, and then it increases to 7.92 × 10 −2 Ω cm after annealing at 300 °C. From the analysis of X-ray photoelectron spectroscopy, the concentration of oxygen vacancies in He plasma treated n + a-IGZO does not change much after thermal annealing at 300 °C, indicating thermally stable n + a-IGZO, even for TFTs with channel length L = 4 μm. Field-effect mobility of the coplanar a-IGZO TFTs with He plasma treatment changes from 10.7 to 9.2 cm 2 /V s after annealing at 300 °C, but the performance of the a-IGZO TFT with Ar or H 2 plasma treatment degrades significantly after 300 °C annealing

  17. Local electrical properties of thermally grown oxide films formed on duplex stainless steel surfaces

    Science.gov (United States)

    Guo, L. Q.; Yang, B. J.; He, J. Y.; Qiao, L. J.

    2018-06-01

    The local electrical properties of thermally grown oxide films formed on ferrite and austenite surfaces of duplex stainless steel at different temperatures were investigated by Current sensing atomic force microscopy, X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). The current maps and XPS/AES analyses show that the oxide films covering austenite and ferrite surfaces formed at different temperatures exhibit different local electrical characteristics, thickness and composition. The dependence of electrical conductivity of oxide films covering austenite and ferrite surface on the formation temperature is attributed to the film thickness and semiconducting structures, which is intrinsically related to thermodynamics and kinetics process of film grown at different temperature. This is well elucidated by corresponding semiconductor band structures of oxide films formed on austenite and ferrite phases at different temperature.

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

    Science.gov (United States)

    Papadimitropoulos, G; Davazoglou, D

    2011-09-01

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

  19. Morphological and thermal properties of photodegradable biocomposite films

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2013-07-01

    Full Text Available Biocomposites containing ultraviolet (UV) radiation absorbing inorganic nanofillers are of great interest in food packaging applications. The biodegradable polylactide (PLA) composite films were prepared by solvent casting method by incorporating 1...

  20. Thermal transport properties of polycrystalline tin-doped indium oxide films

    International Nuclear Information System (INIS)

    Ashida, Toru; Miyamura, Amica; Oka, Nobuto; Sato, Yasushi; Shigesato, Yuzo; Yagi, Takashi; Taketoshi, Naoyuki; Baba, Tetsuya

    2009-01-01

    Thermal diffusivity of polycrystalline tin-doped indium oxide (ITO) films with a thickness of 200 nm has been characterized quantitatively by subnanosecond laser pulse irradiation and thermoreflectance measurement. ITO films sandwiched by molybdenum (Mo) films were prepared on a fused silica substrate by dc magnetron sputtering using an oxide ceramic ITO target (90 wt %In 2 O 3 and 10 wt %SnO 2 ). The resistivity and carrier density of the ITO films ranged from 2.9x10 -4 to 3.2x10 -3 Ω cm and from 1.9x10 20 to 1.2x10 21 cm -3 , respectively. The thermal diffusivity of the ITO films was (1.5-2.2)x10 -6 m 2 /s, depending on the electrical conductivity. The thermal conductivity carried by free electrons was estimated using the Wiedemann-Franz law. The phonon contribution to the heat transfer in ITO films with various resistivities was found to be almost constant (λ ph =3.95 W/m K), which was about twice that for amorphous indium zinc oxide films

  1. Thermal and Mechanical Properties of Poly(butylene succinate Films Reinforced with Silica

    Directory of Open Access Journals (Sweden)

    Sangviroon Nanthaporn

    2015-01-01

    Full Text Available In recent year, bioplastics have become more popular resulting from the growing concerns on environmental issues and the rising fossil fuel price. However, their applications were limited by its mechanical and thermal properties. The aim of this research is thus to improve mechanical and thermal properties of PBS bioplastic films by reinforcing with silica. Due to the poor interfacial interaction between the PBS matrix and silica, glycidyl methacrylate grafted poly(butylene succinate (PBS-g-GMA was used as a compatibilizer in order to improve the interaction between bioplastic films and filler. PBS-g-GMA was prepared in a twin-screw extruder and analyzed by the FTIR spectrometer. PBS and silica were then mixed in a twin-screw extruder and processed into films by a chill-roll cast extruder. The effects of silica loading on thermal and mechanical properties of the prepared bioplastic films were investigated. It was found that the mechanical properties of PBS/silica composite films were improved when 1%wt of silica was added. However, the mechanical properties decreased with increasing silica loading due to the agglomeration of silica particles. The results also show that the silica/PBS films with PBS-g-GMA possessed improved mechanical properties over the films without the compatibilizer.

  2. Optical thermal sensor based on cholesteric film refilled with mixture of toluene and ethanol.

    Science.gov (United States)

    Li, Yong; Liu, Yanjun; Luo, Dan

    2017-10-16

    We demonstrate an optical thermal sensor based on cholesteric film refilled with mixture of toluene and ethanol. The thermal response mechanism is mainly based on the thermal expansion effect induce by toluene, where the ethanol is used for refractive index adjustment to determine the initial refection band position of cholesteric film. The ethanol-toluene mixture was used to adjust the color tunability with the temperature in relation with the habits of people (blue as cold, green as safe and red as hot). A broad temperature range of 86 °C and highly sensitivity of 1.79 nm/ °C are achieved in proposed thermal sensor, where the reflective color red-shifts from blue to red when environmental temperature increases from -6 °C to 80 °C. This battery-free thermal sensor possesses features including simple fabrication, low-cost, and broad temperature sensing range, showing potential application in scientific research and industry.

  3. Coupling of near-field thermal radiative heating and phonon Monte Carlo simulation: Assessment of temperature gradient in n-doped silicon thin film

    International Nuclear Information System (INIS)

    Wong, Basil T.; Francoeur, Mathieu; Bong, Victor N.-S.; Mengüç, M. Pinar

    2014-01-01

    Near-field thermal radiative exchange between two objects is typically more effective than the far-field thermal radiative exchange as the heat flux can increase up to several orders higher in magnitudes due to tunneling of evanescent waves. Such an interesting phenomenon has started to gain its popularity in nanotechnology, especially in nano-gap thermophotovoltaic systems and near-field radiative cooling of micro-/nano-devices. Here, we explored the existence of thermal gradient within an n-doped silicon thin film when it is subjected to intensive near-field thermal radiative heating. The near-field radiative power density deposited within the film is calculated using the Maxwell equations combined with fluctuational electrodynamics. A phonon Monte Carlo simulation is then used to assess the temperature gradient by treating the near-field radiative power density as the heat source. Results indicated that it is improbable to have temperature gradient with the near-field radiative heating as a continuous source unless the source comprises of ultra-short radiative pulses with a strong power density. - Highlights: • This study investigates temperature distribution in an n-doped silicon thin film. • Near-field radiative heating is treated as a volumetric phenomenon. • The temperature gradient is computed using phonon MC simulation. • Temperature of thin film can be approximated as uniform for radiation calculations. • If heat source is a pulsed radiation, a temperature gradient can be established

  4. Optical and electrical properties of thermally evaporated In49Se48Sn3 films

    International Nuclear Information System (INIS)

    Salem, A.M.; El-Gendy, Y.A.; El-Sayad, E.A.

    2009-01-01

    Nearly stoichiometric thin films of In 49 Se 48 Sn 3 were deposited at room temperature, by conventional thermal evaporation of the presynthesized materials, onto precleaned glass substrates. The microstructural studies on the as-deposited and annealed films, using transmission electron microscopy and diffraction (TEMD), revealed that the as-deposited films are amorphous in nature, while those annealed at 498 K are crystalline. The optical properties of the investigated films were determined from the transmittance and reflectance data, in the spectral range 650-2500 nm. An analysis of the optical absorption spectra revealed a non-direct energy gap characterizing the amorphous films, while both allowed and forbidden direct energy gaps characterized the crystalline films. The electrical resistance of the deposited films was carried out during heating and cooling cycles in the temperature range 300-600 K. The results show an irreproducible behavior, while after crystallization the results become reproducible. The analysis of the temperature dependence of the resistance (ln(R) vs. 1000/T) for crystalline films shows two straight lines corresponding to both extrinsic and intrinsic conduction. The room temperature I-V characteristics of the as-deposited films sandwiched between similar Ag metal electrodes shows an ohmic behavior, while non-ohmic behavior attributed to space charge limited conduction has been observed when the films are sandwiched between dissimilar Ag/Al metal electrodes.

  5. Effects of moisture content on mechanical properties, transparency, and thermal stability of yuba film.

    Science.gov (United States)

    Zhang, Siran; Kim, Nayeon; Yokoyama, Wallace; Kim, Yookyung

    2018-03-15

    Yuba is the skin formed at the surface during the heating of soymilk. The 3rd, 7th, and 11th films were evaluated for properties at different RH. At 39% RH, the 11th film had the lowest moisture, while the 3rd film had the highest moisture. However, at 75% RH, reverse moisture results were obtained. The tensile strengths of the 3rd and 11th films were highest at 15% moisture, whereas the tensile strength of the 7th film was highest at 25% moisture. Elongation of the 3rd (127%) and 11th (85%) films were highest at 25% moisture. The light transmittance of the films was low and opaque at 5% moisture. The films were transparent at 23%-28% moisture, but became opaque as the moisture increased. The films at 39% RH (ΔH, 113-203J/g) had higher thermal stability than those at 87% RH (ΔH, 315-493J/g). Moisture content markedly changed the yuba film properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Investigation of nanocrystalline thin cobalt films thermally evaporated on Si(100) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Kozłowski, W., E-mail: wkozl@std2.phys.uni.lodz.pl [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Balcerski, J.; Szmaja, W. [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Piwoński, I. [Department of Materials Technology and Chemistry, Faculty of Chemistry, University of Łódź, Pomorska 163, 90-236 Łódź (Poland); Batory, D. [Institute of Materials Science and Engineering, Łódź University of Technology, Stefanowskiego 1/15, 90-924 Łódź (Poland); Miękoś, E. [Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Łódź, Tamka 12, 91-403 Łódź (Poland); and others

    2017-03-15

    We have made a quantitative study of the morphological and magnetic domain structures of 100 nm thick nanocrystalline cobalt films thermally evaporated on naturally oxidized Si(100) substrates. The morphological structure is composed of densely packed grains with the average grain size (35.6±0.8) nm. The grains exhibit no geometric alignment and no preferred elongation on the film surface. In the direction perpendicular to the film surface, the grains are aligned in columns. The films crystallize mainly in the hexagonal close-packed phase of cobalt and possess a crystallographic texture with the hexagonal axis perpendicular to the film surface. The magnetic domain structure consists of domains forming a maze stripe pattern with the average domain size (102±6) nm. The domains have their magnetizations oriented almost perpendicularly to the film surface. The domain wall energy, the domain wall thickness and the critical diameter for single-domain particle were determined. - Highlights: • 100 nm thick nanocrystalline cobalt films on Si(100) were studied quantitatively. • The grains are densely packed and possess the average size (35.6±0.8) nm. • The films have a texture with the hexagonal axis perpendicular to the film surface. • The magnetic domains form a maze stripe pattern with the average size (102±6) nm. • The domains are magnetized almost perpendicularly to the film surface.

  7. 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.

  8. Influence of grain boundaries on elasticity and thermal conductivity of nanocrystalline diamond films

    International Nuclear Information System (INIS)

    Mohr, Markus; Daccache, Layal; Horvat, Sebastian; Brühne, Kai; Jacob, Timo; Fecht, Hans-Jörg

    2017-01-01

    Diamond combines several outstanding material properties such as the highest thermal conductivity and highest elastic moduli of all materials. This makes diamond an interesting candidate for a multitude of applications. Nonetheless, nanocrystalline diamond films, layers and coatings, usually show properties different to those of single crystalline diamond. This is usually attributed to the larger volume fraction of the grain boundaries with atomic structure different from the single crystal. In this work we measured Young's modulus and thermal conductivity of nanocrystalline diamond films with average grain sizes ranging from 6 to 15 nm. The measured thermal conductivities are modeled considering the thermal boundary conductance between grains as well as a grain size effect on the phonon mean free path. We make a comparison between elastic modulus and thermal boundary conductance of the grain boundaries G_k for different nanocrystalline diamond films. We conclude that the grain boundaries thermal boundary conductance G_k is a measure of the cohesive energy of the grain boundaries and therefore also of the elastic modulus of the nanocrystalline diamond films.

  9. Polarized neutron reflectivity study of a thermally treated MnIr/CoFe exchange bias system.

    Science.gov (United States)

    Awaji, Naoki; Miyajima, Toyoo; Doi, Shuuichi; Nomura, Kenji

    2010-12-01

    It has recently been found that the exchange bias of a MnIr/CoFe system can be increased significantly by adding a thermal treatment to the bilayer. To reveal the origin of the higher exchange bias, we performed polarized neutron reflectivity measurements at the JRR-3 neutron source. The magnetization vector near the MnIr/CoFe interface for thermally treated samples differed from that for samples without the treatment. We propose a model in which the pinned spin area at the interface is extended due to the increased roughness and atomic interdiffusion that result from the thermal treatment.

  10. Plasma-treated Langmuir-Blodgett reduced graphene oxide thin film for applications in biophotovoltaics

    Science.gov (United States)

    Ibrahim, Siti Aisyah; Jaafar, Muhammad Musoddiq; Ng, Fong-Lee; Phang, Siew-Moi; Kumar, G. Ghana; Majid, Wan Haliza Abd; Periasamy, Vengadesh

    2018-01-01

    The surface optimization and structural characteristics of Langmuir-Blodgett (LB) reduced graphene oxide thin (rGO) film treated by argon plasma treatment were studied. In this work, six times deposition of rGO was deposited on a clean glass substrate using the LB method. Plasma technique involving a variation of plasma power, i.e., 20, 60, 100 and 140 W was exposed to the LB-rGO thin films under argon ambience. The plasma treatment generally improves the wettability or hydrophilicity of the film surface compared to without treatment. Maximum wettability was observed at a plasma power of 20 W, while also increasing the adhesion of the rGO film with the glass substrate. The multilayer films fabricated were characterized by means of spectroscopic, structural and electrical studies. The treatment of rGO with argon plasma was found to have improved its biocompatibility, and thus its performance as an electrode for biophotovoltaic devices has been shown to be enhanced considerably.

  11. Sensitive coating for water vapors detection based on thermally sputtered calcein thin films.

    Science.gov (United States)

    Kruglenko, I; Shirshov, Yu; Burlachenko, J; Savchenko, A; Kravchenko, S; Manera, M G; Rella, R

    2010-09-15

    In this paper the adsorption properties of thermally sputtered calcein thin films towards water and other polar molecules vapors are studied by different characterization techniques: quartz crystal microbalance, surface plasmon resonance and visible spectroscopy. Sensitivity of calcein thin films to water vapors resulted much higher as compared with those of a number of dyes whose structure was close to that of calcein. All types of sensors with calcein coatings have demonstrated linear concentration dependences in the wide range of water vapor pressure from low concentrations up to 27,000 ppm (close to saturation). At higher concentrations of water vapor all sensors demonstrate the abrupt increase of the response (up to two orders). A theoretical model is advanced explaining the adsorption properties of calcein thin films taking into account their chemical structure and peculiarities of molecular packing. The possibility of application of thermally sputtered calcein films in sensing technique is discussed. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  12. Preparation of polyvinyl alcohol graphene oxide phosphonate film and research of thermal stability and mechanical properties.

    Science.gov (United States)

    Li, Jihui; Song, Yunna; Ma, Zheng; Li, Ning; Niu, Shuai; Li, Yongshen

    2018-05-01

    In this article, flake graphite, nitric acid, peroxyacetic acid and phosphoric acid are used to prepare graphene oxide phosphonic and phosphinic acids (GOPAs), and GOPAs and polyvinyl alcohol (PVA) are used to synthesize polyvinyl alcohol graphene oxide phosphonate and phosphinate (PVAGOPs) in the case of faint acidity and ultrasound irradiation, and PVAGOPs are used to fabricate PVAGOPs film, and the structure and morphology of GOPAs, PVAGOPs and PVAGOPs film are characterized, and the thermal stability and mechanical properties of PVAGOPs film are investigated. Based on these, it has been proved that GOPAs consist of graphene oxide phosphonic acid and graphene oxide phosphinic acid, and there are CP covalent bonds between them, and PVAGOPs are composed of GOPAs and PVA, and there are six-member lactone rings between GOPAs and PVA, and the thermal stability and mechanical properties of PVAGOPs film are improved effectively. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Dewetting of Epitaxial Silver Film on Silicon by Thermal Annealing

    Science.gov (United States)

    Sanders, Charlotte E.; Kellogg, Gary L.; Shih, C.-K.

    2013-03-01

    It has been shown that noble metals can grow epitaxially on semiconducting and insulating substrates, despite being a non-wetting system: low temperature deposition followed by room temperature annealing leads to atomically flat film morphology. However, the resulting metastable films are vulnerable to dewetting, which has limited their utility for applications under ambient conditions. The physics of this dewetting is of great interest but little explored. We report on an investigation of the dewetting of epitaxial Ag(111) films on Si(111) and (100). Low energy electron microscopy (LEEM) shows intriguing evolution in film morphology and crystallinity, even at temperatures below 100oC. On the basis of these findings, we can begin to draw compelling inferences about film-substrate interaction and the kinetics of dewetting. Financial support is from NSF, DGE-0549417 and DMR-0906025. This work was performed, in part, at the Center for Integrated Nanotechnologies, User Facility operated for the U.S. DOE Office of Science. Sandia National Lab is managed and operated by Sandia Corp., a subsidiary of Lockheed Martin Corp., for the U.S. DOE's National Nuclear Security Administration under DE-AC04-94AL85000.

  14. Transport properties of MnTe films with cracks produced in thermal cycling process

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Liang; Wang, Zhenhua; Zhang, Zhidong [Institute of Metal Research, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shenyang National Laboratory for Materials Science, Shenyang (China)

    2017-10-15

    As a promising material in antiferromagnetic spintronics, MnTe films manifested complex characteristics according to previous reports. In this work, we investigate in details the temperature dependence of resistivity of MnTe films grown on SiO{sub 2}/Si substrate and focus on the divaricating of cooling and warming resistivity-temperature (R-T) curves. It is found that such a divaricating in resistivity is associated with cracks produced in thermal cycles. By comparing the crystalline character and the morphology before and after the cycles, we verify the appearance of cracks and the release of stress in the films. Based on the temperature dependence of thermal-expansion coefficient of Si and MnTe, the origin of the cracks is the mismatched thermal-expansion coefficient (α). The humps, which only appear in the R-T curve of the first cooling process, are attributed to the produced cracks and/or the unreleased stress. (orig.)

  15. 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.

  16. Thermal characterization of polycrystalline diamond thin film heat spreaders grown on GaN HEMTs

    Science.gov (United States)

    Zhou, Yan; Ramaneti, Rajesh; Anaya, Julian; Korneychuk, Svetlana; Derluyn, Joff; Sun, Huarui; Pomeroy, James; Verbeeck, Johan; Haenen, Ken; Kuball, Martin

    2017-07-01

    Polycrystalline diamond (PCD) was grown onto high-k dielectric passivated AlGaN/GaN-on-Si high electron mobility transistor (HEMT) structures, with film thicknesses ranging from 155 to 1000 nm. Transient thermoreflectance results were combined with device thermal simulations to investigate the heat spreading benefit of the diamond layer. The observed thermal conductivity (κDia) of PCD films is one-to-two orders of magnitude lower than that of bulk PCD and exhibits a strong layer thickness dependence, which is attributed to the grain size evolution. The films exhibit a weak temperature dependence of κDia in the measured 25-225 °C range. Device simulation using the experimental κDia and thermal boundary resistance values predicts at best a 15% reduction in peak temperature when the source-drain opening of a passivated AlGaN/GaN-on-Si HEMT is overgrown with PCD.

  17. Tuning thermal conductivity in homoepitaxial SrTiO{sub 3} films via defects

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Charles M. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501 (United States); Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Wilson, Richard B.; Cahill, David G. [Department of Materials Science and Engineering and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States); Schäfer, Anna; Schubert, Jürgen [Peter Grünberg Institute (PGI9-IT), JARA-Fundamentals of Future Information Technology, Research Centre Jülich, D-52425 Jülich (Germany); Mundy, Julia A.; Holtz, Megan E. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Muller, David A. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853 (United States); Schlom, Darrell G. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853-1501 (United States); Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853 (United States)

    2015-08-03

    We demonstrate the ability to tune the thermal conductivity of homoepitaxial SrTiO{sub 3} films deposited by reactive molecular-beam epitaxy by varying growth temperature, oxidation environment, and cation stoichiometry. Both point defects and planar defects decrease the longitudinal thermal conductivity (k{sub 33}), with the greatest decrease in films of the same composition observed for films containing planar defects oriented perpendicular to the direction of heat flow. The longitudinal thermal conductivity can be modified by as much as 80%—from 11.5 W m{sup −1}K{sup −1} for stoichiometric homoepitaxial SrTiO{sub 3} to 2 W m{sup −1}K{sup −1} for strontium-rich homoepitaxial Sr{sub 1+δ}TiO{sub x} films—by incorporating (SrO){sub 2} Ruddlesden-Popper planar defects.

  18. Film-Evaporation MEMS Tunable Array for Picosat Propulsion and Thermal Control

    Science.gov (United States)

    Alexeenko, Alina; Cardiff, Eric; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Film-Evaporation MEMS Tunable Array (FEMTA) concept for propulsion and thermal control of picosats exploits microscale surface tension effect in conjunction with temperature- dependent vapor pressure to realize compact, tunable and low-power thermal valving system. The FEMTA is intended to be a self-contained propulsion unit requiring only a low-voltage DC power source to operate. The microfabricated thermal valving and very-high-integration level enables fast high-capacity cooling and high-resolution, low-power micropropulsion for picosats that is superior to existing smallsat micropropulsion and thermal management alternatives.

  19. 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%.

  20. Room-temperature voltage tunable phonon thermal conductivity via reconfigurable interfaces in ferroelectric thin films.

    Science.gov (United States)

    Ihlefeld, Jon F; Foley, Brian M; Scrymgeour, David A; Michael, Joseph R; McKenzie, Bonnie B; Medlin, Douglas L; Wallace, Margeaux; Trolier-McKinstry, Susan; Hopkins, Patrick E

    2015-03-11

    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. 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%.

  1. Ultra-high carrier mobility InSb film by rapid thermal annealing on glass substrate

    Directory of Open Access Journals (Sweden)

    Charith Jayanada Koswaththage

    2016-11-01

    Full Text Available InSb films were deposited on both mica and glass substrates using thermal evaporation and subjected to FA or RTA. Crystallinity, composition and electrical properties were investigated. High Hall electron mobility as high as 25,000 cm2/(Vs was obtained with the capped InSb film by keeping the In:Sb ratio after RTA at 520°C for 30 sec or more without adopting epitaxial growth on glass.

  2. Electrical properties of thermally evaporated nickel-dimethylglyoxime thin films

    Science.gov (United States)

    Dakhel, A. A.; Ali-Mohamed Ahmed, Y.

    2005-06-01

    Thin Bis-(dimethylglyoximato)nickel(II) [Ni(DMG)2] films of amorphous and crystalline structures were prepared by vacuum deposition on Si (P) substrates. The films were characterised by X-ray fluorescence and X-ray diffraction. The constructed Al/Ni(DMG)2/Si(P) metal-insulator-semiconductor devices were characterised by the measurement of the gate-voltage dependence of their capacitance and ac conductance, from which the surface states density Dit of insulator/semiconductor interface and the density of the fixed charges in the oxide were determined. The ac electrical conduction and dielectric properties of the Ni(DMG)2-Silicon structure were studied at room temperature. The data of the ac measurements of the annealed films follow the correlated barrier-hopping CBH mode, from which the fundamental absorption bandgap, the minimum hopping distance, and other parameters of the model were determined.

  3. Composition and microstructure of beryllium carbide films prepared by thermal MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    He, Yu-dan; Luo, Jiang-shan; Li, Jia; Meng, Ling-biao; Luo, Bing-chi; Zhang, Ji-qiang; Zeng, Yong; Wu, Wei-dong, E-mail: wuweidongding@163.com

    2016-02-15

    Highlights: • Non-columnar-crystal Be{sub 2}C films were firstly prepared by thermal MOCVD. • Beryllium carbide was always the dominant phase in the films. • α-Be and carbon existed in films deposited below and beyond 400 °C, respectively. • Morphology evolved with temperatures and no columnar grains were characterized. • The preferred substrate temperature for depositing high quality Be{sub 2}C films was 400 °C. - Abstract: Beryllium carbide films without columnar-crystal microstructures were prepared on the Si (1 0 0) substrate by thermal metal organic chemical vapor deposition using diethylberyllium as precursor. The influence of the substrate temperature on composition and microstructure of beryllium carbide films was systematically studied. Crystalline beryllium carbide is always the dominant phase according to XRD analysis. Meanwhile, a small amount of α-Be phase exists in films when the substrate temperature is below 400 °C, and hydrocarbon or amorphous carbon exists when the temperature is beyond 400 °C. Surfaces morphology shows transition from domes to cylinders, to humps, and to tetraquetrous crystalline needles with the increase of substrate temperature. No columnar grains are characterized throughout the thickness as revealed from the cross-section views. The average densities of these films are determined to be 2.04–2.17 g/cm{sup 3}. The findings indicate the substrate temperature has great influences on the composition and microstructure of the Be{sub 2}C films grown by thermal MOCVD.

  4. Simultaneous measurements of thermal conductivity and electrical conductivity of micro-machined Silicon films

    International Nuclear Information System (INIS)

    Hagino, H; Kawahara, Y; Goto, A; Miyazaki, K

    2012-01-01

    The in-plane effective thermal conductivity of free-standing Si thin films with periodic micropores was measured at -100 to 0 °C. The Si thin films with micropores were prepared from silicon-on-insulator (SOI) wafers by standard microfabrication processes. The dimensions of the free-standing Si thin films were 200μm×150μm×2 μm, with staggered 4 μm pores having an average pitch of 4 mm. The Si thin film serves both as a heater and thermometer. The average temperature rise of the thin film is a function of its in-plane thermal conductivity. The effective thermal conductivity was calculated using a simple one-dimensional heat conduction model. The measured thermal conductivity was much lower than that expected based on classical model evaluations. A significant phonon size effect was observed even in the microsized structures, and the mean free path for phonons is very long even at the room temperature.

  5. Determining the thermal expansion coefficient of thin films for a CMOS MEMS process using test cantilevers

    International Nuclear Information System (INIS)

    Cheng, Chao-Lin; Fang, Weileun; Tsai, Ming-Han

    2015-01-01

    Many standard CMOS processes, provided by existing foundries, are available. These standard CMOS processes, with stacking of various metal and dielectric layers, have been extensively applied in integrated circuits as well as micro-electromechanical systems (MEMS). It is of importance to determine the material properties of the metal and dielectric films to predict the performance and reliability of micro devices. This study employs an existing approach to determine the coefficients of thermal expansion (CTEs) of metal and dielectric films for standard CMOS processes. Test cantilevers with different stacking of metal and dielectric layers for standard CMOS processes have been designed and implemented. The CTEs of standard CMOS films can be determined from measurements of the out-of-plane thermal deformations of the test cantilevers. To demonstrate the feasibility of the present approach, thin films prepared by the Taiwan Semiconductor Manufacture Company 0.35 μm 2P4M CMOS process are characterized. Eight test cantilevers with different stacking of CMOS layers and an auxiliary Si cantilever on a SOI wafer are fabricated. The equivalent elastic moduli and CTEs of the CMOS thin films including the metal and dielectric layers are determined, respectively, from the resonant frequency and static thermal deformation of the test cantilevers. Moreover, thermal deformations of cantilevers with stacked layers different to those of the test beams have been employed to verify the measured CTEs and elastic moduli. (paper)

  6. 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

    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...... is able to operate in relatively high range of temperature with long working period without failure. Furthermore, effects of implementing thermal cycling on stability analysis of a TEG sample are considered. By testing the thermoelectric thin film specimen during a thermal cycling, behavior of the TEG...

  7. Structural and thermal properties of γ – irradiated Bombyx mori silk fibroin films

    Energy Technology Data Exchange (ETDEWEB)

    Madhukumar, R.; Asha, S.; Rao, B. Lakshmeesha; Shivananda, C. S.; Harish, K. V.; Sangappa, E-mail: syhalabhavi@yahoo.co.in [Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore - 574199 (India); Sarojini, B. K. [Department of Studies in Chemistry, Mangalore University, Mangalagangotri, Mangalore - 574199 (India); Somashekar, R. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore - 570006 (India)

    2015-06-24

    The gamma radiation-induced change in structural and thermal properties of Bombyx mori silk fibroin films were investigated and have been correlated with the applied radiation doses. Irradiation of samples were carried out in dry air at room temperature using Co-60 source, and radiation doses are in the range of 0 - 300 kGy. Structural and thermal properties of the irradiated silk films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) and compared with unirradiated sample. Interesting results are discussed in this report.

  8. Thermal properties and corrosion resistance of organoclay/epoxy resin film

    Science.gov (United States)

    Baiquni, M.; Soegijono, B.

    2018-03-01

    Hybrid materials organoclay/epoxy resin films were prepared by varying organoclay content in epoxy resin as a matrix. The film were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and thermal conductivity. TGA and FT-IR results confirmed that the melting temperature shifted to a lower point. The thermal conductivity and corrosion resistant generally increase with increasing organoclay content. The changes on these properties may due to cross link between organoclay and epoxy.

  9. Preparation by thermal evaporation under vacuum of thin nickel films without support

    International Nuclear Information System (INIS)

    Prugne, P.; Garin, P.; Lechauguette, G.

    1959-01-01

    This note deals with the preparation of nickel films without support by means of the technique described but using a new evaporation apparatus. In effect it was necessary, in order to obtain these nickel films, to modify the thermal evaporation conditions. An attempt to obtain a film without support after evaporation in a conventional apparatus led almost invariably to defeat. This appeared to be due to the high concentration of oxygen and of various vapors (diffusion pumps, degassing, etc.) present in the residual atmosphere of the conventional evaporation system. Reprint of a paper published in 'Le Vide, N. 74, March-April 1958, p. 82-83

  10. Influence of electron irradiation on the structural and thermal properties of silk fibroin films

    Energy Technology Data Exchange (ETDEWEB)

    Asha, S.; Sangappa,; Sanjeev, Ganesh, E-mail: ganeshanjeev@rediffmail.com [Department of Studies in Physics, Mangalore University, Mangalagangotri, Mangalore - 574 199 (India)

    2015-06-24

    Radiation-induced changes in Bombyx mori silk fibroin (SF) films under electron irradiation were investigated and correlated with dose. SF films were irradiated in air at room temperature using 8 MeV electron beam in the range 0-150 kGy. Various properties of the irradiated SF films were studied using X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Electron irradiation was found to induce changes in the physical and thermal properties, depending on the radiation dose.

  11. Thermally treated grass fibers as colonizable substrate for beneficial bacterial inoculum

    NARCIS (Netherlands)

    Trifonova, R.D.; Postma, J.; Ketelaars, J.J.M.H.; Elsas, van J.D.

    2008-01-01

    This study investigates how thermally treated (i.e., torrefied) grass, a new prospective ingredient of potting soils, is colonized by microorganisms. Torrefied grass fibers (TGF) represent a specific colonizable niche, which is potentially useful to establish a beneficial microbial community that

  12. Using kinetic models to predict thermal degradation of fire-retardant-treated plywood roof sheathing

    Science.gov (United States)

    Patricia Lebow; Jerrold E. Winandy; Patricia K. Lebow

    2003-01-01

    Between 1985-1995 a substantial number of multifamily housing units in the Eastern and Southern U.S. experienced problems with thermally degraded fire-retardant-treated (FRT) plywood roof sheathing. A series of studies conducted at the USDA Forest Service, Forest Products Laboratory (FPL), examined the materials, chemical mechanisms, and process implications and has...

  13. Structural, optoelectronic, luminescence and thermal properties of Ga-doped zinc oxide thin films

    International Nuclear Information System (INIS)

    Shinde, S.S.; Shinde, P.S.; Oh, Y.W.; Haranath, D.; Bhosale, C.H.; Rajpure, K.Y.

    2012-01-01

    Highlights: ► The ecofriendly deposition of Ga-doped zinc oxide. ► Influence of Ga doping onto physicochemical properties in aqueous media. ► Electron–phonon coupling by Raman. ► Chemical bonding structure and valence band analysis by XPS. - Abstract: Ga-doped ZnO thin films are synthesized by chemical spray pyrolysis onto corning glass substrates in aqueous media. The influence of gallium doping on to the photoelectrochemical, structural, Raman, XPS, morphological, optical, electrical, photoluminescence and thermal properties have been investigated in order to achieve good quality films. X-ray diffraction study depicts the films are polycrystalline and fit well with hexagonal (wurtzite) crystal structure with strong orientations along the (0 0 2) and (1 0 1) planes. Presence of E 2 high mode in Raman spectra indicates that the gallium doping does not change the wurtzite structure. The coupling strength between electron and LO phonon has experimentally estimated. In order to understand the chemical bonding structure and electronic states of the Ga-doped ZnO thin films XPS analysis have been studied. SEM images shows the films are adherent, compact, densely packed with hexagonal flakes and spherical grains. Optical transmittance and reflectance measurements have been carried out. Room temperature PL spectra depict violet, blue and green emission in deposited films. The specific heat and thermal conductivity study shows the phonon conduction behavior is dominant in these polycrystalline films.

  14. Morphology and thermal properties of PLA films plasticized with aliphatic oligoesters

    International Nuclear Information System (INIS)

    Inacio, Erika M.; Dias, Marcos L.; Lima, Maria Celiana P.

    2015-01-01

    The addition of plasticizers to poly(lactic acid) (PLA) is one of the known ways of changing its ductility, making possible the modification of its mechanical and thermal properties. In this work, it was synthesized two biodegradable aliphatic oligoesters: oligo(trimethylene sebacate) (OST) and oligo(trimethylene malonate) (OMT), and these oligomers were used as plasticizer in cast films of commercial film grade PLA at concentrations of 1, 5 and 10 wt% of each plasticizer. X-ray diffraction (XRD) was used to investigate the morphology and differential scanning calorimetry (DSC) was also used aiming the evaluation of the thermal properties of these films. The PLA films containing no plasticizer showed an amorphous behavior, and the addition of PMT on the PLA films acted, simultaneously, decreasing the Tg, and rising the material's crystallinity. In contrast, the increased addition of OST to the PLA films did not change the Tg, and equally, did not have a significant changes in the material's crystallinity. Therefore, it was possible to observe the effect of the concentration of oligomers on the crystallinity of the films as well as the no plasticizer effect of the OST. (author)

  15. Influence of Philosamia ricini silk fibroin components on morphology, secondary structure and thermal properties of chitosan biopolymer film.

    Science.gov (United States)

    Prasong, S; Nuanchai, K; Wilaiwan, S

    2009-09-15

    This study aimed to prepare Eri (Philosamia ricini) Silk Fibroin (SF)/chitosan (CS) blend films by a solvent evaporation method and to compare the blend films with both native SF and CS films. Influence of SF ratios on the morphology, secondary structure and thermal decomposition of the CS blend films were investigated. The native SF and CS films were uniform and homogeneous without phase separation. For the blend films, the uniform can be found less than 60% of SF composition. All of SF/CS blend films showed both SF and CS characteristics. FT-IR results showed that the blend films composed of both random coil and beta-sheet with predominant of beta-sheet form. Interaction of intermolecular between SF and CS have occurred which were measured by thermogravimetric thermograms. Increasing of SF contents was leading to the increase of beta-sheet structures which were enhanced the thermal stability of the CS blend films.

  16. Use of residual hydrocarbons treated by Thermal Plasma (recovery of energy by-products)

    International Nuclear Information System (INIS)

    Carreno B, J.A.; Pacheco S, J.O.; Ramos F, F.; Cruz A, A.; Duran G, M.

    2001-01-01

    The emergence of new technologies is getting greater importance for the control of pollution. One of them is the destruction of hazardous wastes treated by thermal plasma, which is of special interest for the efficient treatment of the hazardous wastes since the heat generated by thermal plasma is able to destroy the molecular bonds generating solids and gaseous products which do not represent danger for the human being and the environment. The thermal plasma is the suitable technology for treating a wide range of hazardous wastes, including the residual hydrocarbons from the refinement process of petroleum, plasma exceeds the barrier of 3000 Centigrade. The efficiency of the degradation of residues is greater than 99.99%. Toxic emissions are not generated to environment as SO 2 , NO x and CO 2 neither dioxins and furans by being a pyrolysis process. The use of hydrogen as fuel does not generate pollution to environment. (Author)

  17. 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.

  18. 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...

  19. Thermally stimulated currents in α-HgI2 polycrystalline films

    International Nuclear Information System (INIS)

    Shiu, Y.-T.; Huang, T.-J.; Shih, C.-T.; Su, C.-F.; Lan, S.-M.; Chiu, K.-C.

    2007-01-01

    A study of thermally stimulated currents (TSC) is applied to α-HgI 2 polycrystalline films grown by physical vapour deposition with various thermal boundary conditions. Five TSC peaks are clearly observed and numerically fitted. The activation energy and the density of the trapping centre that corresponds to each TSC peak are then calculated. Finally, the effects of the deposition conditions on the TSC results are discussed

  20. A thermal sensor for water using self-heated NTC thick-film segmented thermistors

    OpenAIRE

    Nikolić, Maria Vesna; Radojčić, B. M.; Aleksić, Obrad; Luković, Miloljub D.; Nikolić, Pantelija

    2011-01-01

    A simple thermal (heat loss) sensor system was designed in a small plastic tube housing using a negative thermal coefficient (NTC) thick-film thermistor as a self-heating sensor. The voltage power supply [range constant voltage (RCV)-range constant voltage] uses the measured input water temperature to select the applied voltage in steps (up and down) in order to enable operation of the sensor at optimal sensitivity for different water temperatures. The input water temperature was measured usi...

  1. Effect of acid treated carbon nanotubes on mechanical, rheological and thermal properties of polystyrene nanocomposites

    KAUST Repository

    Amr, Issam Thaher

    2011-09-01

    In this work, multiwall carbon nanotubes (CNT) were functionalized by acid treatment and characterized using Fourier Transform Infrared Spectroscopy (FTIR) and thermogravimetric analysis (TGA). Polystyrene/CNT composites of both the untreated and acid treated carbon nanotubes were prepared by thermal bulk polymerization without any initiator at different loadings of CNT. The tensile tests showed that the addition of 0.5 wt.% of acid treated CNT results in 22% increase in Young\\'s modulus. The DSC measurements showed a decrease in glass transition temperature (Tg) of PS in the composites. The rheological studies at 190 °C showed that the addition of untreated CNT increases the viscoelastic behavior of the PS matrix, while the acid treated CNT acts as plasticizer. Thermogravimetric analysis indicated that the incorporation of CNT into PS enhanced the thermal properties of the matrix polymer. © 2011 Elsevier Ltd. All rights reserved.

  2. 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)

  3. Laser diode with thermal conducting, current confining film

    Science.gov (United States)

    Hawrylo, Frank Z. (Inventor)

    1980-01-01

    A laser diode formed of a rectangular parallelopiped body of single crystalline semiconductor material includes regions of opposite conductivity type indium phosphide extending to opposite surfaces of the body. Within the body is a PN junction at which light can be generated. A stripe of a conductive material is on the surface of the body to which the P type region extends and forms an ohmic contact with the P type region. The stripe is spaced from the side surfaces of the body and extends to the end surfaces of the body. A film of germanium is on the portions of the surface of the P type region which is not covered by the conductive stripe. The germanium film serves to conduct heat from the body and forms a blocking junction with the P type region so as to confine the current through the body, across the light generating PN junction, away from the side surfaces of the body.

  4. 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 ...

  5. 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

  6. [Research of aeration with bio-film technology to treat urban landscape water].

    Science.gov (United States)

    Song, Ying-Wei; Nie, Zhi-Dan; Nian, Yue-Gang; Huang, Min-Sheng; Huang, Jian-Jun; Yan, Hai-Hong; Zhang, Yang

    2008-01-01

    Research of the aeration with bio-film technology was carried out to treat scenic water of a sanatorium in Beijing. The aim of the research was improving the water habitat by increasing the transparency and reducing the concentration of N and P. The equipments were set in a 5,000 m2 water area, which combined the plug flow jet aerator with the elastic biological filler. The research indicated that the transparency increased from 25 cm to 120 cm by the technology. The removal efficiencies of NH4(+)-N, NO3(-)-N and TP were 86.6% , 90% and 73.3%, but there was only 22.4% for TN. The concentration of DO increased from 4.3 mg/L to 7 mg/L. In a word, the aeration with bio-film technology was an effective measure to improve the water habitat by increasing the transparency.

  7. Physical properties of very thin SnS films deposited by thermal evaporation

    International Nuclear Information System (INIS)

    Cheng Shuying; Conibeer, Gavin

    2011-01-01

    SnS films with thicknesses of 20–65 nm have been deposited on glass substrates by thermal evaporation. The physical properties of the films were investigated using X-ray diffraction (XRD), scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and ultraviolet–visible-near infrared spectroscopy at room temperature. The results from XRD, XPS and Raman spectroscopy analyses indicate that the deposited films mainly exhibit SnS phase, but they may contain a tiny amount of Sn 2 S 3 . The deposited SnS films are pinhole free, smooth and strongly adherent to the surfaces of the substrates. The color of the SnS films changes from pale yellow to brown with the increase of the film thickness from 20 nm to 65 nm. The very smooth surfaces of the thin films result in their high reflectance. The direct bandgap of the films is between 2.15 eV and 2.28 eV which is much larger than 1.3 eV of bulk SnS, this is deserving to be investigated further.

  8. Influence of thin film nickel pretreatment on catalytic thermal chemical vapor deposition of carbon nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Tiggelaar, R.M. [Mesoscale Chemical Systems, MESA" + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Thakur, D.B.; Nair, H.; Lefferts, L.; Seshan, K. [Catalytic Processes and Materials, MESA" + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Gardeniers, J.G.E., E-mail: j.g.e.gardeniers@utwente.nl [Mesoscale Chemical Systems, MESA" + Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    2013-05-01

    Nickel and other metal nanoparticles are known to be active as catalysts in the synthesis of carbon nanofibers. In this paper we investigate how dewetting and break-up of nickel thin films depends on film thickness, film–substrate interaction and pretreatment conditions. This is evaluated for films evaporated on oxidized silicon and fused silica substrates with or without tantalum coating, which were subsequently exposed to different pretreatment atmospheres (vacuum, nitrogen, air and hydrogen; 1 h, 650 °C). Atomic force microscopy, scanning electron microscopy and energy dispersive X-ray analysis were used to characterize the films. Pretreated Ni films were subjected to a thermal catalytic chemical vapor deposition procedure with brief ethylene exposures (0.5–3 min, 635 °C). It was found that only on the spherical nanoparticles originating from a hydrogen pretreatment of a Ni film with Ta adhesion layer, homogeneously distributed, randomly-oriented, well-attached, and semi-crystalline carbon nanofibers be synthesized. - Highlights: • On the formation of nanoparticles required for carbon nanofiber (CNF) synthesis • Various evaporated thin films on oxidized silicon and fused silica: Ni and Ni/Ta • Pretreatment of nickel-based thin films in vacuum, nitrogen, air and hydrogen • Only on reduced Ni/Ta fast – within 3 min – initiation of CNF nucleation and growth.

  9. 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.

  10. Effect of temperature oscillation on thermal characteristics of an aluminum thin film

    Science.gov (United States)

    Ali, H.; Yilbas, B. S.

    2014-12-01

    Energy transport in aluminum thin film is examined due to temperature disturbance at the film edge. Thermal separation of electron and lattice systems is considered in the analysis, and temperature variation in each sub-system is formulated. The transient analysis of frequency-dependent and frequency-independent phonon radiative transport incorporating electron-phonon coupling is carried out in the thin film. The dispersion relations of aluminum are used in the frequency-dependent analysis. Temperature at one edge of the film is oscillated at various frequencies, and temporal response of phonon intensity distribution in the film is predicted numerically using the discrete ordinate method. To assess the phonon transport characteristics, equivalent equilibrium temperature is introduced. It is found that equivalent equilibrium temperature in the electron and lattice sub-systems oscillates due to temperature oscillation at the film edge. The amplitude of temperature oscillation reduces as the distance along the film thickness increases toward the low-temperature edge of the film. Equivalent equilibrium temperature attains lower values for the frequency-dependent solution of the phonon transport equation than that corresponding to frequency-independent solution.

  11. Fabrication and characterization of In2S3 thin films deposited by thermal evaporation technique

    International Nuclear Information System (INIS)

    Timoumi, A.; Bouzouita, H.; Kanzari, M.; Rezig, B.

    2005-01-01

    Indium sulphide, In 2 S 3 , thin films present an alternative to conventional CdS films as buffer layer for CIS-based thin film solar cells. The objective is to eliminate toxic cadmium for environmental reasons. Indium sulphide is synthesized and deposited by single source vacuum thermal evaporation method on glass substrates. The films are analyzed by X-ray diffraction (XRD) and spectrophotometric measurements. They have a good crystallinity, homogeneity and adhesion. The X-ray diffraction analysis confirmed the initial amorphous nature of the deposited InS film and phase transition into crystalline In 2 S 3 formed upon annealing at free air for 250 deg. C substrate temperature for 2 h. The optical constants of the deposited films were obtained from the analysis of the experimental recorded transmission and reflectance spectral data over the wavelength range of 300-1800 nm. We note that the films annealed at 250 deg. C for 2 h show a good homogeneity with 80% transmission. An analysis of the optical absorption data of the deposited films revealed an optical direct band gap energy in the range of 2.0-2.2 eV

  12. Improved luminescence intensity and stability of thermal annealed ZnO incorporated Alq3 composite films.

    Science.gov (United States)

    Cuba, M; Muralidharan, G

    2015-11-01

    The 30 wt% of ZnO (weight percentage of ZnO has been optimised) incorporated tris- (8-hydroxyquinoline)aluminum (Alq3) has been synthesised and coated on to glass substrates using dip coating method. The structural and optical properties of the Alq3/ZnO composite film after thermal annealing from 50 to 300 °C insteps 50° has been studied and reported. XRD pattern reveals the presence of crystalline ZnO in all the annealed films. The films annealed above 150 °C reveal the presence of crystalline Alq3 along with crystalline ZnO. The FTIR spectra confirm the presence of hydroxyquinoline and ZnO vibration in all the annealed composite films. The composite films annealed above 150 °C show a partial sublimation and degradation of hydroxyquinoline compounds. The ZnO incorporated composite films (Alq3/ZnO) exhibit two emission peaks, one corresponding to ZnO at 487 nm and another at 513 nm due to Alq3. The films annealed at 200 °C exhibit maximum photoluminescence (PL) intensity than pristine film at 513 nm when excited at 390 nm.

  13. Comparison of the Thermal Degradation of Heavily Nb-Doped and Normal PZT Thin Films.

    Science.gov (United States)

    Yang, Jeong-Suong; Kang, YunSung; Kang, Inyoung; Lim, SeungMo; Shin, Seung-Joo; Lee, JungWon; Hur, Kang Heon

    2017-03-01

    The degradation of niobium-doped lead zirconate titanate (PZT) and two types of PZT thin films were investigated. Undoped PZT, two-step PZT, and heavily Nb-doped PZT (PNZT) around the morphotropic phase boundary were in situ deposited under optimum condition by RF-magnetron sputtering. All 2- [Formula: see text]-thick films had dense perovskite columnar grain structure and self-polarized (100) dominant orientation. PZT thin films were deposited on Pt/TiO x bottom electrode on Si wafer, and PNZT thin film was on Ir/TiW electrode with the help of orientation control. Sputtered PZT films formed on microelectromechanical system (MEMS) gyroscope and the degradation rates were compared at different temperatures. PNZT showed the best resistance to the thermal degradation, followed by two-step PZT. To clarify the effect of oxygen vacancies on the degradation of the film at high temperature, photoluminescence measurement was conducted, which confirmed that oxygen vacancy rate was the lowest in heavy PNZT. Nb-doping PZT thin films suppressed the oxygen deficit and made high imprint with self-polarization. This defect distribution and high internal field allowed PNZT thin film to make the piezoelectric sensors more stable and reliable at high temperature, such as reflow process of MEMS packaging.

  14. Enhancement in microstructural and optoelectrical properties of thermally evaporated CdTe films for solar cells

    Science.gov (United States)

    Chander, Subhash; Dhaka, M. S.

    2018-03-01

    The optimization of microstructural and optoelectrical properties of a thin layer is an important step prior device fabrication process, so an enhancement in these properties of thermally evaporated CdTe thin films is reported in this communication. The films having thickness 450 nm and 850 nm were deposited on thoroughly cleaned glass and indium tin oxide (ITO) substrates followed by annealing at 450 °C in air atmosphere. These films were characterized for microstructural and optoelectrical properties employing X-ray diffraction, scanning electron microscopy coupled with energy-dispersive spectroscopy, UV-Vis spectrophotometer and source meter. The films found to be have zinc-blende cubic structure with preferred reflection (111) while the crystallographic parameters and direct energy band gap are strongly influenced by the film thickness. The surface morphology studies show that the films are uniform, smooth, homogeneous and nearly dense-packed as well as free from voids and pitfalls as where elemental analysis revealed the presence of Cd and Te element in the deposited films. The electrical analysis showed linear behavior of current with voltage while conductivity is decreased for higher thickness. The results show that the microstructural and optoelectrical properties of CdTe thin layer could be enhanced by varying thickness and films having higher thickness might be processed as promising absorber thin layer to the CdTe-based solar cells.

  15. 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.

  16. Thermally evaporated Ag nanoparticle films for plasmonic enhancement in organic solar cells: effects of particle geometry

    NARCIS (Netherlands)

    Haidari, G.; Hajimahmoodzadeh, M.; Fallah, H.R.; Peukert, A.; Chanaewa, A.; von Hauff, E.L.

    2015-01-01

    We report on the simple fabrication of Ag NP films via thermal evaporation and subsequent annealing. The NPs are formed on indium tin oxide electrodes, coated with PEDOT:PSS and implemented into PCPDTBT:PC70BM solar cells. Scanning electron microscopy and atomic force microscopy are used to

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

    DEFF Research Database (Denmark)

    Mirhosseini, M.; Rezania, A.; Rosendahl, L.

    2017-01-01

    In this study, performance and stability of zinc antimonide thin film thermoelectric sample is analyzed under transient thermal conditions. The thermoelectric materials are deposited on glass based substrate where the heat flow is parallel with the thermoelectric element length. The specimen...

  18. Plasma processes and film growth of expanding thermal plasma deposited textured zinc oxide

    NARCIS (Netherlands)

    Groenen, R.; Linden, J.L.; Sanden, van de M.C.M.

    2005-01-01

    Plasma processes and film growth of textured zinc oxide deposited from oxygen and diethyl zinc utilizing expanding thermal argon plasma created by a cascaded arc is discussed. In all conditions explored, an excess of argon ions and low temperature electrons is available, which represent the

  19. Thermal Characteristics of Plastic Film Tension in Roll-to-Roll Gravure Printed Electronics

    Directory of Open Access Journals (Sweden)

    Kui He

    2018-02-01

    Full Text Available In the printing section of a roll-to-roll gravure printed electronics machine, the plastic film tension is directly associated with the product quality. The temperature distribution of the plastic film in the printing section is non-uniform, because of the higher drying temperature and the lower room temperature. Furthermore, the drying temperature and the room temperature are not constants in industrial production. As the plastic film is sensitive to temperature, the temperature of the plastic film will affects the web tension in the printing section. In this paper, the thermal characteristics of the plastic film tension in roll-to-roll gravure printed electronics are studied in order to help to improve the product quality. First, the tension model including the factor of temperature is derived based on the law of mass conservation. Then, some simulations and experiments are carried out in order to in-depth research the effects of the drying temperature and room temperature based on the relations between system inputs and outputs. The results show that the drying temperature and room temperature have significant influences on the web tension. The research on the thermal characteristics of plastic film tension would benefit the tension control accuracy for further study.

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

    International Nuclear Information System (INIS)

    Oleksak, R.P.; Hostetler, E.B.; Flynn, B.T.; McGlone, J.M.; Landau, N.P.; Wager, J.F.; Stickle, W.F.; Herman, G.S.

    2015-01-01

    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). 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.

  1. Static magnetism and thermal switching in randomly oriented L10 FePt thin films

    Science.gov (United States)

    Lisfi, A.; Pokharel, S.; Alqarni, A.; Akioya, O.; Morgan, W.; Wuttig, M.

    2018-05-01

    Static magnetism and thermally activated magnetic relaxation were investigated in granular FePt films (20 nm-200 nm thick) with random magnetic anisotropy through hysteresis loop, torque curve and magnetization time dependence measurements. While the magnetism of thicker film (200 nm thick) is dominated by a single switching of the ordered L10 phase, thinner film (20 nm) displays a double switching, which is indicative of the presence of the disordered cubic phase. The pronounced behavior of double switching in thinner film suggests that the film grain boundary is composed of soft cubic magnetic phase. The magnetic relaxation study reveals that magnetic viscosity S of the films is strongly dependent on the external applied field and exhibits a maximum value (12 kAm) around the switching field and a vanishing behavior at low (1 kOe) and large (12 kOe) fields. The activation volume of the thermal switching was found to be much smaller than the physical volume of the granular structure due to the incoherent rotation mode of the magnetization reversal mechanism, which is established to be domain wall nucleation.

  2. 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.

  3. Using high thermal stability flexible thin film thermoelectric generator at moderate temperature

    Science.gov (United States)

    Zheng, Zhuang-Hao; Luo, Jing-Ting; Chen, Tian-Bao; Zhang, Xiang-Hua; Liang, Guang-Xing; Fan, Ping

    2018-04-01

    Flexible thin film thermoelectric devices are extensively used in the microscale industry for powering wearable electronics. In this study, comprehensive optimization was conducted in materials and connection design for fabricating a high thermal stability flexible thin film thermoelectric generator. First, the thin films in the generator, including the electrodes, were prepared by magnetron sputtering deposition. The "NiCu-Cu-NiCu" multilayer electrode structure was applied to ensure the thermal stability of the device used at moderate temperature in an air atmosphere. A design with metal layer bonding and series accordant connection was then employed. The maximum efficiency of a single PN thermocouple generator is >11%, and the output power loss of the generator is <10% after integration.

  4. 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.

  5. Iron Oxide Films Prepared by Rapid Thermal Processing for Solar Energy Conversion.

    Science.gov (United States)

    Wickman, B; Bastos Fanta, A; Burrows, A; Hellman, A; Wagner, J B; Iandolo, B

    2017-01-16

    Hematite is a promising and extensively investigated material for various photoelectrochemical (PEC) processes for energy conversion and storage, in particular for oxidation reactions. Thermal treatments during synthesis of hematite are found to affect the performance of hematite electrodes considerably. Herein, we present hematite thin films fabricated via one-step oxidation of Fe by rapid thermal processing (RTP). In particular, we investigate the effect of oxidation temperature on the PEC properties of hematite. Films prepared at 750 °C show the highest activity towards water oxidation. These films show the largest average grain size and the highest charge carrier density, as determined from electron microscopy and impedance spectroscopy analysis. We believe that the fast processing enabled by RTP makes this technique a preferred method for investigation of novel materials and architectures, potentially also on nanostructured electrodes, where retaining high surface area is crucial to maximize performance.

  6. Treating high-mercury-containing lamps using full-scale thermal desorption technology.

    Science.gov (United States)

    Chang, T C; You, S J; Yu, B S; Chen, C M; Chiu, Y C

    2009-03-15

    The mercury content in high-mercury-containing lamps are always between 400 mg/kg and 200,000 mg/kg. This concentration is much higher than the 260 mg/kg lower boundary recommended for the thermal desorption process suggested by the US Resource Conservation and Recovery Act. According to a Taiwan EPA survey, about 4,833,000 cold cathode fluorescent lamps (CCFLs), 486,000 ultraviolet lamps and 25,000 super high pressure mercury lamps (SHPs) have been disposed of in the industrial waste treatment system, producing 80, 92 and 9 kg-mercury/year through domestic treatment, offshore treatment and air emissions, respectively. To deal with this problem we set up a full-scale thermal desorption process to treat and recover the mercury from SHPs, fluorescent tube tailpipes, fluorescent tubes containing mercury-fluorescent powder, and CCFLs containing mercury-fluorescent powder and monitor the use of different pre-heating temperatures and desorption times. The experimental results reveal that the average thermal desorption efficiency of SHPs and fluorescent tube tailpipe were both 99.95%, while the average thermal desorption efficiencies of fluorescent tubes containing mercury-fluorescent powder were between 97% and 99%. In addition, a thermal desorption efficiency of only 69.37-93.39% was obtained after treating the CCFLs containing mercury-fluorescent powder. These differences in thermal desorption efficiency might be due to the complexity of the mercury compounds contained in the lamps. In general, the thermal desorption efficiency of lamps containing mercury-complex compounds increased with higher temperatures.

  7. Thermal Effect on the Structural, Electrical, and Optical Properties of In-Line Sputtered Aluminum Doped Zinc Oxide Films Explored with Thermal Desorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Shang-Chou Chang

    2014-01-01

    Full Text Available This work investigates the thermal effect on the structural, electrical, and optical properties of aluminum doped zinc oxide (AZO films. The AZO films deposited at different temperatures were measured using a thermal desorption system to obtain their corresponding thermal desorption spectroscopy (TDS. In addition to obtaining information of thermal desorption, the measurement of TDS also has the effect of vacuum annealing on the AZO films. The results of measuring TDS imply part of the doped aluminum atoms do not stay at substituted zinc sites in AZO films. The (002 preferential direction of the AZO films in X-ray diffraction spectra shifts to a lower angle after measurement of TDS. The grain size grows and surface becomes denser for all AZO films after measurement of TDS. The carrier concentration, mobility, and average optical transmittance increase while the electrical resistivity decreases for AZO films after measurement of TDS. These results indicate that the AZO films deposited at 200°C are appropriate selections if the AZO films are applied in device fabrication of heat-produced process.

  8. Hydroxylated graphene-based flexible carbon film with ultrahigh electrical and thermal conductivity.

    Science.gov (United States)

    Ding, Jiheng; Ur Rahman, Obaid; Zhao, Hongran; Peng, Wanjun; Dou, Huimin; Chen, Hao; Yu, Haibin

    2017-09-29

    Graphene-based films are widely used in the electronics industry. Here, surface hydroxylated graphene sheets (HGS) have been synthesized from natural graphite (NG) by a rapid and efficient molten hydroxide-assisted exfoliation technique. This method enables preparation of aqueous dispersible graphene sheets with a high dispersed concentration (∼10.0 mg ml -1 ) and an extraordinary production yield (∼100%). The HGS dispersion was processed into graphene flexible film (HGCF) through fast filtration, annealing treatment and mechanical compression. The HGS endows graphene flexible film with a high electrical conductivity of 11.5 × 10 4 S m -1 and a superior thermal conductivity of 1842 W m -1 K -1 . Simultaneously, the superflexible HGCF could endure 3000 repeated cycles of bending or folding. As a result, this graphene flexible film is expected to be integrated into electronic packaging and high-power electronics applications.

  9. Highly transparent, flexible, and thermally stable superhydrophobic ORMOSIL aerogel thin films.

    Science.gov (United States)

    Budunoglu, Hulya; Yildirim, Adem; Guler, Mustafa O; Bayindir, Mehmet

    2011-02-01

    We report preparation of highly transparent, flexible, and thermally stable superhydrophobic organically modified silica (ORMOSIL) aerogel thin films from colloidal dispersions at ambient conditions. The prepared dispersions are suitable for large area processing with ease of coating and being directly applicable without requiring any pre- or post-treatment on a variety of surfaces including glass, wood, and plastics. ORMOSIL films exhibit and retain superhydrophobic behavior up to 500 °C and even on bent flexible substrates. The surface of the films can be converted from superhydrophobic (contact angle of 179.9°) to superhydrophilic (contact angle of <5°) by calcination at high temperatures. The wettability of the coatings can be changed by tuning the calcination temperature and duration. The prepared films also exhibit low refractive index and high porosity making them suitable as multifunctional coatings for many application fields including solar cells, flexible electronics, and lab on papers.

  10. Film-based Sensors with Piezoresistive Molecular Conductors as Active Components Strain Damage and Thermal Regeneration

    Directory of Open Access Journals (Sweden)

    Elena Laukhina

    2011-02-01

    Full Text Available The article is addressed to the development of flexible all-organic bi layer (BL film-based sensors being capable of measuring strain as a well-defined electrical signal in a wide range of elongations and temperature. The purpose was achieved by covering polycarbonate films with the polycrystalline layer of a high piezoresistive organic molecular conductor. To determine restrictions for sensor applications, the effect of monoaxial strain on the resistance and texture of the sensing layers of BL films was studied. The experiments have shown that the maximum strain before fracture is about 1 %. A thermal regeneration of the sensing layer of the BL film-based sensors that were damaged by cyclic load is also described. These sensors are able to take the place of conventional metal-based strain and pressure gages in low cost innovative controlling and monitoring technologies.

  11. Effect of nitrogen doping on the thermal conductivity of GeTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Fallica, Roberto; Longo, Massimo; Wiemer, Claudia [Laboratorio MDM, IMM-CNR, Agrate Brianza (Italy); Varesi, Enrico; Fumagalli, Luca; Spadoni, Simona [Micron Semiconductor Italia, Agrate Brianza (Italy)

    2013-12-15

    The 3{omega} method was employed to determine the effect of nitrogen doping (5 at.%) on the thermal conductivity of sputtered thin films of stoichiometric GeTe (a material of interest for phase change memories). It was found that nitrogen doping has a detrimental effect on the thermal conductivity of GeTe in both phases, but less markedly in the amorphous (-25%) than in the crystalline one (-40%). On the opposite, no effect could be detected on the measured thermal boundary resistance between these films and SiO{sub 2}, within the experimental error. Our results agree with those obtained by molecular dynamic simulation of amorphous GeTe. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. 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.

  13. 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.

  14. In situ thermal residual stress evolution in ultrathin ZnO and Ag films studied by synchrotron x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Renault, P.O., E-mail: Pierre.olivier.renault@univ-poitiers.fr [Institut P' , CNRS, Universite de Poitiers, UPR 3346, 86962 Futuroscope (France); Krauss, C.; Le Bourhis, E.; Geandier, G. [Institut P' , CNRS, Universite de Poitiers, UPR 3346, 86962 Futuroscope (France); Benedetto, A. [Saint-Gobain Recherche (SGR), 93303 Aubervilliers (France); Grachev, S.Y.; Barthel, E. [Lab. Surface du Verre et Interfaces (SVI), UMR-CNRS 125, 93303 Aubervilliers (France)

    2011-12-30

    Residual-stress evolution in sputtered encapsulated ZnO/Ag/ZnO stack has been studied in-situ by synchrotron x-ray diffraction when heat treated. The ZnO/Ag/ZnO stack encapsulated into Si{sub 3}N{sub 4} layers and deposited on (001) Si substrates was thermally heated from 25 Degree-Sign C to 600 Degree-Sign C and cooled down to 25 Degree-Sign C. X-ray diffraction 2D patterns captured continuously during the heat treatment allowed monitoring the diffraction peak shifts of both Ag (15 nm thick) and ZnO (10 nm and 50 nm thick) sublayers. Due to the mismatch between the coefficients of thermal expansion, the silicon substrate induced compressive thermal stresses in the films during heating. We first observed a linear increase of the compressive stress state in both Ag and ZnO films and then a more complex elastic-stress evolution starts to operate from about 100 Degree-Sign C for Ag and about 250 Degree-Sign C for ZnO. Thermal contraction upon cooling seems to dominate so that the initial compressive film stresses relax by about 300 and 700 MPa after thermal treatment for ZnO and Ag, respectively. The overall behavior is discussed in terms of structural changes induced by the heat treatment.

  15. Technological and Thermal Properties of Thermoplastic Composites Filled with Heat-treated Alder Wood

    Directory of Open Access Journals (Sweden)

    Mürşit Tufan

    2016-02-01

    Full Text Available This study investigated the effect of heat-treated wood content on the water absorption, mechanical, and thermal properties of wood plastic composites (WPCs. The WPCs were produced from various loadings (30, 40, and 50 wt% of heat-treated and untreated alder wood flours (Alnus glutinosa L. using high-density polyethylene (HDPE with 3 wt% maleated polyethylene (MAPE coupling agent. All WPC formulations were compression molded into a hot press for 3 min at 170 ºC. The WPCs were evaluated using mechanical testing, Fourier transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, and differential scanning calorimetry (DSC. The mechanical property values of the WPC specimens decreased with increasing amounts of the heat-treated wood flour, except for the tensile modulus values. The heat treatment of alder wood slightly increased the thermal stability of the WPCs compared with the reference WPCs. The crystallization degree (Xc and the enthalpy of crystallization of the WPCs slightly decreased with increasing content of the heat-treated wood flour. However, all WPCs containing the heat-treated alder wood flour showed a higher crystallinity degree than that of the virgin HDPE.

  16. Photoluminescence properties of ZnO films grown on InP by thermally oxidizing metallic Zn films

    CERN Document Server

    Chen, S J; Zhang, J Y; Lu, Y M; Shen, D Z; Fan, X W

    2003-01-01

    Photoluminescence (PL) properties of ZnO films grown on (001) InP substrates by thermal oxidization of metallic Zn films, in which oxygen vacancies and interstitial Zn ions are compensated by P ions diffusing from (001) InP substrates, are investigated. X-ray diffraction spectra indicate that P ions have diffused into the Zn films and chemically combined with Zn ions to form Zn sub 3 P sub 2. Intense free exciton emission dominates the PL spectra of ZnO films with very weak deep-level emission. Low-temperature PL spectra at 79 K are dominated by neutral-donor bound exciton emission at 3.299 eV (I sub 4) with a linewidth of 17.3 meV and neutral-acceptor bound exciton emission at 3.264 eV. The free exciton emission increases with increasing temperature and eventually dominates the emission spectrum for temperature higher than 170 K. Furthermore, the visible emission around 2.3 eV correlated with oxygen deficiencies and interstitial Zn defects was quenched to a remarkable degree by P diffusing from InP substrate...

  17. Photoluminescence properties of ZnO films grown on InP by thermally oxidizing metallic Zn films

    International Nuclear Information System (INIS)

    Chen, S J; Liu, Y C; Zhang, J Y; Lu, Y M; Shen, D Z; Fan, X W

    2003-01-01

    Photoluminescence (PL) properties of ZnO films grown on (001) InP substrates by thermal oxidization of metallic Zn films, in which oxygen vacancies and interstitial Zn ions are compensated by P ions diffusing from (001) InP substrates, are investigated. X-ray diffraction spectra indicate that P ions have diffused into the Zn films and chemically combined with Zn ions to form Zn 3 P 2 . Intense free exciton emission dominates the PL spectra of ZnO films with very weak deep-level emission. Low-temperature PL spectra at 79 K are dominated by neutral-donor bound exciton emission at 3.299 eV (I 4 ) with a linewidth of 17.3 meV and neutral-acceptor bound exciton emission at 3.264 eV. The free exciton emission increases with increasing temperature and eventually dominates the emission spectrum for temperature higher than 170 K. Furthermore, the visible emission around 2.3 eV correlated with oxygen deficiencies and interstitial Zn defects was quenched to a remarkable degree by P diffusing from InP substrates

  18. Thermal plasma fabricated lithium niobate-tantalate films on sapphire substrate

    International Nuclear Information System (INIS)

    Kulinich, S.A.; Yoshida, T.; Yamamoto, H.; Terashima, K.

    2003-01-01

    We report the deposition of LiNb 1-x Ta x O 3 (0≤x≤1) films on (001) sapphire substrates in soft vacuum using a radio frequency thermal plasma. The growth rate, crystallinity, c-axis orientation, and surface roughness were examined as functions of substrate temperature, precursor feed rate, and substrate surface condition. The film Nb/Ta ratio was well controlled by using an appropriate uniform mixture of lithium-niobium and lithium-tantalum alkoxide solutions. The epitaxy and crystallinity of the films were much improved when the film growth rate was raised from 20 to 180-380 nm/min, where the films with the (006) rocking curve full width at half maximum values as low as 0.12 deg. -0.2 deg. could be produced. The film roughness could be reduced by using a liquid precursor with higher metal concentrations, achieving the root-mean-square value on the order of 5 nm. The refractive indices of the films are in good correspondence with their composition and crystallinity

  19. Thermal stability of amorphous carbon films grown by pulsed laser deposition

    Science.gov (United States)

    Friedmann, T. A.; McCarty, K. F.; Barbour, J. C.; Siegal, M. P.; Dibble, Dean C.

    1996-03-01

    The thermal stability in vacuum of amorphous tetrahedrally coordinated carbon (a-tC) films grown on Si has been assessed by in situ Raman spectroscopy. Films were grown in vacuum on room-temperature substrates using laser fluences of 12, 22, and 45 J/cm2 and in a background gas of either hydrogen or nitrogen using a laser fluence of 45 J/cm2. The films grown in vacuum at high fluence (≳20J/cm2) show little change in the a-tC Raman spectra with temperature up to 800 °C. Above this temperature the films convert to glassy carbon (nanocrystalline graphite). Samples grown in vacuum at lower fluence or in a background gas (H2 or N2) at high fluence are not nearly as stable. For all samples, the Raman signal from the Si substrate (observed through the a-tC film) decreases in intensity with annealing temperature indicating that the transparency of the a-tC films is decreasing with temperature. These changes in transparency begin at much lower temperatures (˜200 °C) than the changes in the a-tC Raman band shape and indicate that subtle changes are occurring in the a-tC films at lower temperatures.

  20. 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

  1. Experimental studies on the electronic structure of pyrite FeS2 films prepared by thermally sulfurizing iron films

    International Nuclear Information System (INIS)

    Zhang Hui; Wang Baoyi; Zhang Rengang; Zhang Zhe; Wei Long; Qian Haijie; Su Run; Kui Rexi

    2006-01-01

    Pyrite FeS 2 films have been prepared by thermally sulfurizing iron films deposited by magnetron sputtering. The electronic structures were studies by X-ray absorption near edge structure and X-ray photoemission spectrum. The results show that an S 3p valence band with relatively higher intensity compared to the calculation exists in 2-10 eV range and a high density below the Fermi level of Fe 3d states were detected. A second gap of 2.8 eV in the unoccupied density of states was found above the conduction band which was 2.4 eV by experimentally calculation. The difference between t 2g and e g which were formed in an octahedral crystal field was computed to be 2.1 eV. (authors)

  2. Development of a machine treating removed shells and others in thermal and nuclear power stations

    International Nuclear Information System (INIS)

    Daiho, Koichi; Iwao, Takenobu

    1981-01-01

    The living things removed form the cooling water systems in thermal and nuclear power stations, such as shells and jelly fish, have been disposed by burying in the premises, but it is the actual situation that the occurrence of bad smell and the securing of land for burying are the worries. Accordingly, a machine for deodorizing the removed living things was manufactured for trial, and the treatment experiment was carried out in Chita Power Station. This treating machine dries the removed living things around 200 deg C, and makes the deodorizing treatment. The treated products can be utilized effectively as fertilizer, and the prospect to put this machine in practical use as a waste treatment machine of resource re-utilization type was obtained. General Technical Research Institute, Chubu Electric Power Co., Inc., has developed a machine treating abandoned fish for making organic fertilizer, and its principle was applied to the development of this treating machine. The treating capacity of this machine is 1 t/day, and the power consumption is 9.3 kW. The waste oil from power stations of about 15 l/h is used as the fuel. A crusher, a constant feed screw conveyer and a rotary kiln for drying are used. In the treating experiment, about 30 t of shells and others were treated during 51 days. The results are reported. (Kako, I.)

  3. Influence of Absorption of Thermal Radiation in the Surface Water Film on the Characteristics and Ignition Conditions

    Directory of Open Access Journals (Sweden)

    Syrodoy Samen V.

    2016-01-01

    Full Text Available The results of the mathematical modeling of homogeneous particle ignition process of coal-water fuel covered with water film have been presented in article. The set co-occurring physical (inert heating, evaporation of water film and thermochemical (thermal degradation, inflammation process have been considered. Heat inside the film has been considered as the model of radiation-conductive heat transfer. Delay times have been determined according to the results of numerical modeling of the ignition. It has been shown that the water film can have a significant impact on performance and the ignition conditions. It has been found that heating main fuel layer occurs in the process of evaporation of water film. For this reason, the next (after the evaporation of the water film thermal preparation (coal heating, thermal decomposition of the organic part of the fuel and inflammation occur faster.

  4. 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.

  5. Analysis of dual-phase-lag thermal behaviour in layered films with temperature-dependent interface thermal resistance

    International Nuclear Information System (INIS)

    Liu, K-C

    2005-01-01

    This work analyses theoretically the dual-phase-lag thermal behaviour in two-layered thin films with an interface thermal resistance, which is predicted by the radiation boundary condition model. The effect of the interface thermal resistance on the transmission-reflection phenomenon, induced by a pulsed volumetric source adjacent to the exterior surface of one layer, is investigated. Due to the difference between the two layers in the relaxation times, τ q and τ T , and the nonlinearity of the interfacial boundary condition, complexity is introduced and some mathematical difficulties are involved in solving the present problem. A hybrid application of the Laplace transform method and a control-volume formulation are used along with the linearization technique. The results show that the effect of the thermophysical properties on the behaviour of the energy passing across the interface gradually reduces with increasing interface thermal resistance. The lagging thermal behaviour depends on the magnitude of τ T and τ q more than on the ratio of τ T /τ q

  6. Investigation of film boiling thermal hydraulics under FCI conditions. Results of a numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, T.N.; Dinh, A.T.; Nourgaliev, R.R.; Sehgal, B.R. [Div. of Nuclear Power Safety Royal Inst. of Tech. (RIT), Brinellvaegen 60, 10044 Stockholm (Sweden)

    1998-01-01

    Film boiling on the surface of a high-temperature melt jet or of a melt particle is one of key phenomena governing the physics of fuel-coolant interactions (FCIs) which may occur during the course of a severe accident in a light water reactor (LWR). A number of experimental and analytical studies have been performed, in the past, to address film boiling heat transfer and the accompanying hydrodynamic aspects. Most of the experiments have, however, been performed for temperature and heat flux conditions, which are significantly lower than the prototypic conditions. For ex-vessel FCIs, high liquid subcooling can significantly affect the FCI thermal hydraulics. Presently, there are large uncertainties in predicting natural-convection film boiling of subcooled liquids on high-temperature surfaces. In this paper, research conducted at the Division of Nuclear Power Safety, Royal Institute of Technology (RIT/NPS), Stockholm, concerning film-boiling thermal hydraulics under FCI condition is presented. Notably, the focus is placed on the effects of (1) water subcooling, (2) high-temperature steam properties, (3) the radiation heat transfer and (4) mixing zone boiling dynamics, on the vapor film characteristics. Numerical investigations are performed using a novel CFD modeling concept named as the local-homogeneous-slip model (LHSM). Results of the analytical and numerical studies are discussed with respect to boiling dynamics under FCI conditions. (author)

  7. Evolution of structural and magnetic properties of sputtered nanocrystalline Co thin films with thermal annealing

    International Nuclear Information System (INIS)

    Kumar, Dileep; Gupta, Ajay

    2007-01-01

    Ultrafine grain films of cobalt prepared using ion-beam sputtering have been studied using X-ray diffraction (XRD), X-ray reflectivity (XRR), atomic force microscopy (AFM) and magneto-optical Kerr effect (MOKE) measurements. As-prepared films have very smooth surface owing to the ultrafine nature of the grains. Evolution of the structure and morphology of the film with thermal annealing has been studied and the same is correlated with the magnetic properties. Above an annealing temperature of 300 deg. C, the film gradually transforms from HCP to FCC phase that remains stable at room temperature. A significant contribution of the surface energy, due to small grain size, results in stabilisation of the FCC phase at room temperature. It is found that other processes like stress relaxation, grain texturing and growth also exhibit an enhanced rate above 300 deg. C, and may be associated with an enhanced mobility of the atoms above this temperature. Films possess a uniaxial anisotropy, which exhibits a non-monotonous behaviour with thermal annealing. The observed variation in the anisotropy and coercivity with annealing can be understood in terms of variations in the internal stresses, surface roughness, and grain structure

  8. Effect of Al doping on phase formation and thermal stability of iron nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Tayal, Akhil [Amity Center for Spintronic Materials, Amity University, Sector 125, Noida 201 303 (India); Gupta, Mukul, E-mail: mgupta@csr.res.in [Amity Center for Spintronic Materials, Amity University, Sector 125, Noida 201 303 (India); Pandey, Nidhi [Amity Center for Spintronic Materials, Amity University, Sector 125, Noida 201 303 (India); Gupta, Ajay [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 001 (India); Horisberger, Michael [Laboratory for Developments and Methods, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Stahn, Jochen [Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

    2015-11-25

    In the present work, we systematically studied the effect of Al doping on the phase formation of iron nitride (Fe–N) thin films. Fe–N thin films with different concentration of Al (Al = 0, 2, 3, 6, and 12 at.%) were deposited using dc magnetron sputtering by varying the nitrogen partial pressure between 0 and 100%. The structural and magnetic properties of the films were studied using x-ray diffraction and polarized neutron reflectivity. It was observed that at the lowest doping level (2 at.% of Al), nitrogen rich non-magnetic Fe–N phase gets formed at a lower nitrogen partial pressure as compared to the un-doped sample. Interestingly, we observed that as Al doping is increased beyond 3 at.%, nitrogen rich non-magnetic Fe–N phase appears at higher nitrogen partial pressure as compared to un-doped sample. The thermal stability of films were also investigated. Un-doped Fe–N films deposited at 10% nitrogen partial pressure possess poor thermal stability. Doping of Al at 2 at.% improves it marginally, whereas, for 3, 6 and 12 at.% Al doping, it shows significant improvement. The obtained results have been explained in terms of thermodynamics of Fe–N and Al–N. - Highlights: • Doping effects of Al on Fe–N phase formation is studied. • Phase formation shows a non-monotonic behavior with Al doping. • Low doping levels of Al enhance and high levels retard the nitridation process. • Al doping beyond 3 at.% improve thermal stability of Fe–N films.

  9. 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.

  10. Optical pump-and-probe test system for thermal characterization of thin metal and phase-change films

    International Nuclear Information System (INIS)

    Watabe, Kazuo; Polynkin, Pavel; Mansuripur, Masud

    2005-01-01

    A single-shot optical pump-and-probe test system is reported. The system is designed for thermal characterization of thin-film samples that can change their phase state under the influence of a short and intense laser pulse on a subnanosecond time scale. In combination with numerical analysis, the system can be used to estimate thermal constants of thin films, such as specific heat and thermal conductivity. In-plane and out-of plane thermal conductivity can be estimated independently. The system is intended for use in research on optical data storage and material processing with pulsed laser light. The system design issues are discussed. As application examples, we report on using the system to study thermal dynamics in two different thin-film samples: a gold film on a glass substrate (a single-phase system) and the quadrilayer phase-change stack typical in optical data-storage applications

  11. The film thickness dependent thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Xiudi; Xu Gang, E-mail: xiudixiao@163.com; Xiong Bin; Chen Deming; Miao Lei [Chinese Academy of Sciences, Key Laboratory of Renewable Energy and Gas Hydrates, Guangzhou Institute of Energy Conversion (China)

    2012-03-15

    The monolayer Al{sub 2}O{sub 3}:Ag thin films were prepared by magnetron sputtering. The microstructure and optical properties of thin film after annealing at 700 Degree-Sign C in air were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and spectrophotometer. It revealed that the particle shape, size, and distribution across the film were greatly changed before and after annealing. The surface plasmon resonance absorption and thermal stability of the film were found to be strongly dependent on the film thickness, which was believed to be associated with the evolution process of particle diffusion, agglomeration, and evaporation during annealing at high temperature. When the film thickness was smaller than 90 nm, the film SPR absorption can be attenuated until extinct with increasing annealing time due to the evaporation of Ag particles. While the film thickness was larger than 120 nm, the absorption can keep constant even after annealing for 64 h due to the agglomeration of Ag particles. On the base of film thickness results, the multilayer Al{sub 2}O{sub 3}:Ag solar selective thin films were prepared and the thermal stability test illustrated that the solar selectivity of multilayer films with absorbing layer thickness larger than 120 nm did not degrade after annealing at 500 Degree-Sign C for 70 h in air. It can be concluded that film thickness is an important factor to control the thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers.

  12. Orientation of rapid thermally annealed lead zirconate titanate thin films on (111) Pt substrate

    International Nuclear Information System (INIS)

    Brooks, K.G.; Reaney, I.M.; Klissurska, R.; Huang, Y.; Bursill, L.A.; Setter, N.

    1994-01-01

    The nucleation, growth and orientation of lead zirconate titanate thin films prepared from organometallic precursor solutions by spin coating on (111) oriented platinum substrates and crystallized by rapid thermal annealing was investigated. The effects of pyrolysis temperature, post-pyrolysis thermal treatments, excess lead addition, and Nb dopant substitution are reported. The use of post pyrolysis oxygen anneals at temperatures in the regime of 350-450 deg C was found to strongly effect the kinetics of subsequent amorphous-pyrochlore perovskite crystallization by rapid thermal annealing. It has also allowed films of reproducible microstructure and textures (both (100) and (111)) to be prepared by rapid thermal annealing. It is suggested that such anneals and pyrolysis temperature affect the oxygen concentration/average Pb valence in the amorphous films prior to annealing. The changes in Pb valence state then affect the stability of the transient pyrochlore phase and thus the kinetics of perovskite crystallization. Nb dopant was also found to influence the crystallization kinetics. 28 refs., 18 figs

  13. H-isotope retention and thermal/ion-induced release in boronized films

    International Nuclear Information System (INIS)

    Walsh, D.S.; Doyle, B.L.; Wampler, W.R.; Hays, A.K.

    1990-01-01

    Over the past decade, it has been clearly demonstrated that the composition of the very near surface (∼100nm) of plasma-interactive components plays a determinant role in most processes which occur in the plasma-edge of Tokamaks. Two very successful techniques to effect control of the plasma-wall interaction are (1) in-situ deposition of amorphous carbon or boron-carbon films and (2) the use of He/C conditioning discharges or He glow discharge cleaning to modify the near surface of bulk graphite components. We have deposited boronized layers into Si using plasma-assisted CVD and sputter deposition. The PCVD deposition conditions were as close as possible to those used in TFTR, and some films deposited in TFTR have also been studied. Using these two deposition techniques, B x CH y films have been produced with x varying from 1/2 -- 4, and y from ∼1 (sputtered) to ∼3 (PCVD). Most films also contained significant amounts of 0. Thermal and ion-induced release of H-isotopes from BC films is qualitatively similar to that measured for graphite. Implanted H saturates in these films at a H/host atom ratio of 0.7 which is considerably higher than that of graphite(∼0.4). As-deposited PCVD films are already saturated with H, while sputtered films are not. Sputtered BC films therefore possess an inherent H-pumping capability which could prove to be extremely beneficial to TFTR. 16 refs., 5 figs., 1 tab

  14. Thermal-induced SPR tuning of Ag-ZnO nanocomposite thin film for plasmonic applications

    Science.gov (United States)

    Singh, S. K.; Singhal, R.

    2018-05-01

    The formation of silver (Ag) nanoparticles in a ZnO matrix were successfully synthesized by RF-magnetron sputtering at room temperature. As prepared Ag-ZnO nanocomposite (NCs) thin films were annealed in vacuum at three different temperatures of 300 °C, 400 °C and 500 °C, respectively. The structural modifications for as-deposited and annealed films were estimated by X-ray diffraction and TEM techniques. The crystalline behavior preferably along the c-axis of the hexagonal wurtzite structure was observed in as-deposited Ag-ZnO film and improved significantly with increasing the annealing temperature. The crystallite size of as-deposited film was measured to be 13.6 nm, and increases up to 28.5 nm at higher temperatures. The chemical composition and surface structure of the as-deposited films were estimated by X-ray photoelectron spectroscopy. The presence of Ag nanoparticles with average size of 8.2 ± 0.2 nm, was confirmed by transmission electron microscopy. The strong surface plasmon resonance (SPR) band was observed at the wavelength of ∼565 nm for as-deposited film and a remarkable red shift of ∼22 nm was recorded after the annealing treatment as confirmed by UV-visible spectroscopy. Atomic force microscopy confirmed the grain growth from 60.38 nm to 79.42 nm for as-deposited and higher temperature annealed film respectively, with no significant change in the surface roughness. Thermal induced modifications such as disordering and lattice defects in Ag-ZnO NCs thin films were carried out by Raman spectroscopy. High quality Ag-ZnO NCs thin films with minimum strain and tunable optical properties could be useful in various plasmonic applications.

  15. Study on boron-film thermal neutron converter prepared by pulsed laser deposition

    International Nuclear Information System (INIS)

    Song Zifeng; Ye Shuzhen; Chen Ziyu; Song Liao; Shen Ji

    2011-01-01

    The boron film converter used in the position-sensitive thermal neutron detector is discussed and the method of preparing this converter layer via Pulsed Laser Deposition (PLD) is introduced. The morphology and the composition were studied by Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). Both boron and boride existed on the layer surface. It was shown that the energy intensity of laser beam and the substrate temperature both had an important influence on the surface morphology of the film.

  16. Study on boron-film thermal neutron converter prepared by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Song Zifeng; Ye Shuzhen; Chen Ziyu; Song Liao [Department of Modern Physics, University of Science and Technology of China, Anhui Hefei 230026 (China); Shen Ji, E-mail: shenji@ustc.edu.c [Department of Modern Physics, University of Science and Technology of China, Anhui Hefei 230026 (China)

    2011-02-15

    The boron film converter used in the position-sensitive thermal neutron detector is discussed and the method of preparing this converter layer via Pulsed Laser Deposition (PLD) is introduced. The morphology and the composition were studied by Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). Both boron and boride existed on the layer surface. It was shown that the energy intensity of laser beam and the substrate temperature both had an important influence on the surface morphology of the film.

  17. Thermal Stability of Sulfonated Poly(Ether Ether Ketone) Films: on the Role of Protodesulfonation

    OpenAIRE

    Koziara, Beata; Kappert, Emiel; Ogieglo, Wojciech; Nijmeijer, Dorothea C.; Hempenius, Mark A.; Benes, Nieck Edwin

    2016-01-01

    Thin film and bulk, sulfonated poly(ether ether ketone) (SPEEK) have been subjected to a thermal treatment at 160–250 °C for up to 15 h. Exposing the films to 160 °C already causes partial desulfonation, and heating to temperatures exceeding 200 °C results in increased conjugation in the material, most likely via a slight cross-linking by H-substitution. It is well-known that the sulfonate proton plays a major role in the desulfonation reactions, and exchanging the protons with other cations ...

  18. Study of Perylenetetracarboxylic Acid Dimethylimide Films by Cyclic Thermal Desorption and Scanning Probe Microscopy

    Science.gov (United States)

    Pochtennyi, A. E.; Lappo, A. N.; Il'yushonok, I. P.

    2018-02-01

    Some results of studying the direct-current (DC) conductivity of perylenetetracarboxylic acid dimethylimide films by cyclic oxygen thermal desorption are presented. The microscopic parameters of hopping electron transport over localized impurity and intrinsic states were determined. The bandgap width and the sign of major current carriers were determined by scanning probe microscopy methods (atomic force microscopy, scanning probe spectroscopy, and photoassisted Kelvin probe force microscopy). The possibility of the application of photoassisted scanning tunneling microscopy for the nanoscale phase analysis of photoconductive films is discussed.

  19. 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.

  20. Improved thermal stability of polylactic acid (PLA) composite film via PLA-β-cyclodextrin-inclusion complex systems.

    Science.gov (United States)

    Byun, Youngjae; Rodriguez, Katia; Han, Jung H; Kim, Young Teck

    2015-11-01

    The effects of the incorporation of PLA-β-cyclodextrin-inclusion complex (IC) and β-cyclodextrin (β-CD) on biopolyester PLA films were investigated. Thermal stability, surface morphology, barrier, and mechanical properties of the films were measured at varying IC (1, 3, 5, and 7%) and β-CD (1 and 5%) concentrations. The PLA-IC-composite films (IC-PLA-CFs) showed uniform morphological structure, while samples containing β-CD (β-CD-PLA-CFs) showed high agglomeration of β-CD due to poor interfacial interaction between β-CD and PLA moieties. According to the thermal property analysis, the 5% IC-PLA-CFs showed 6.6 times lower dimensional changes (6.5%) at the temperature range of 20-80°C than that of pure PLA film (43.0%). The increase of IC or β-CD content in the PLA-composite films shifted the glass transition and crystallization temperature to higher temperature regions. The crystallinity of both composite films improved by increasing IC or β-CD content. Both composite films had higher oxygen and water vapor permeability as IC or β-CD content increased in comparison to pure PLA film. All the composite films had less flexibility and lower tensile strength than the pure PLA film. In conclusion, this study shows that the IC technique is valuable to improve the thermal expansion stability of PLA-based films. Published by Elsevier B.V.

  1. Solidification and Biotoxicity Assessment of Thermally Treated Municipal Solid Waste Incineration (MSWI) Fly Ash.

    Science.gov (United States)

    Gong, Bing; Deng, Yi; Yang, Yuanyi; Tan, Swee Ngin; Liu, Qianni; Yang, Weizhong

    2017-06-10

    In the present work, thermal treatment was used to stabilize municipal solid waste incineration (MSWI) fly ash, which was considered hazardous waste. Toxicity characteristic leaching procedure (TCLP) results indicated that, after the thermal process, the leaching concentrations of Pb, Cu, and Zn decreased from 8.08 to 0.16 mg/L, 0.12 to 0.017 mg/L and 0.39 to 0.1 mg/L, respectively, which well met the limits in GB5085.3-2007 and GB16689-2008. Thermal treatment showed a negative effect on the leachability of Cr with concentrations increasing from 0.1 to 1.28 mg/L; nevertheless, it was still under the limitations. XRD analysis suggested that, after thermal treatments, CaO was newly generated. CaO was a main contribution to higher Cr leaching concentrations owing to the formation of Cr (VI)-compounds such as CaCrO₄. SEM/EDS tests revealed that particle adhesion, agglomeration, and grain growth happened during the thermal process and thus diminished the leachability of Pb, Cu, and Zn, but these processes had no significant influence on the leaching of Cr. A microbial assay demonstrated that all thermally treated samples yet possessed strong bactericidal activity according to optical density (OD) test results. Among all samples, the OD value of raw fly ash (RFA) was lowest followed by FA700-10, FA900-10, and FA1100-10 in an increasing order, which indicated that the sequence of the biotoxicity for these samples was RFA > FA700-10 > FA900-10 > FA1100-10. This preliminary study indicated that, apart from TCLP criteria, the biotoxicity assessment was indispensable for evaluating the effect of thermal treatment for MSWI fly ash.

  2. Titanate nanotube thin films with enhanced thermal stability and high-transparency prepared from additive-free sols

    Energy Technology Data Exchange (ETDEWEB)

    Koroesi, Laszlo, E-mail: korosi@enviroinvest.hu [Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi vertanuk tere 1, H-6720 Szeged (Hungary); Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertvaros utca 2, H-7632 Pecs (Hungary); Papp, Szilvia [Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi vertanuk tere 1, H-6720 Szeged (Hungary); Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertvaros utca 2, H-7632 Pecs (Hungary); Hornok, Viktoria [Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi vertanuk tere 1, H-6720 Szeged (Hungary); Oszko, Albert [Department of Physical Chemistry and Materials Science, University of Szeged, Aradi vertanuk tere 1, H-6720 Szeged (Hungary); Petrik, Peter; Patko, Daniel; Horvath, Robert [Institute for Technical Physics and Materials Science MFA, Research Center for Natural Sciences, Konkoly-Thege ut 29-33, H-1121 Budapest (Hungary); Dekany, Imre [Supramolecular and Nanostructured Materials Research Group of the Hungarian Academy of Sciences, University of Szeged, Aradi vertanuk tere 1, H-6720 Szeged (Hungary)

    2012-08-15

    Titanate nanotubes were synthesized from TiO{sub 2} in alkaline medium by a conventional hydrothermal method (150 Degree-Sign C, 4.7 bar). To obtain hydrogen titanates, the as-prepared sodium titanates were treated with either HCl or H{sub 3}PO{sub 4} aqueous solutions. A simple synthesis procedure was devised for stable titanate nanotube sols without using any additives. These highly stable ethanolic sols can readily be used to prepare transparent titanate nanotube thin films of high quality. The resulting samples were studied by X-ray diffraction, N{sub 2}-sorption measurements, Raman spectroscopy, transmission and scanning electron microscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. The comparative results of using two kinds of acids shed light on the superior thermal stability of the H{sub 3}PO{sub 4}-treated titanate nanotubes (P-TNTs). X-ray photoelectron spectroscopy revealed that P-TNTs contains P in the near-surface region and the thermal stability was enhanced even at a low ({approx}0.5 at%) concentration of P. After calcination at 500 Degree-Sign C, the specific surface areas of the HCl- and H{sub 3}PO{sub 4}-treated samples were 153 and 244 m{sup 2} g{sup -1}, respectively. The effects of H{sub 3}PO{sub 4} treatment on the structure, morphology and porosity of titanate nanotubes are discussed. - Graphical Abstract: TEM picture (left) shows P-TNTs with diameters about 5-6 nm. Inset shows a stable titanate nanotube sol illuminated by a 532 nm laser beam. Due to the presence of the nanoparticles the way of the light is visible in the sol. Cross sectional SEM picture (right) as well as ellipsometry revealed the formation of optical quality P-TNT films with thicknesses below 50 nm. Highlights: Black-Right-Pointing-Pointer H{sub 3}PO{sub 4} treatment led to TNTs with high surface area even after calcination at 500 Degree-Sign C. Black-Right-Pointing-Pointer H{sub 3}PO{sub 4}-treated TNTs preserved their nanotube morphology up to 500

  3. 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.

  4. Thermal valorization of post-consumer film waste in a bubbling bed gasifier

    International Nuclear Information System (INIS)

    Martínez-Lera, S.; Torrico, J.; Pallarés, J.; Gil, A.

    2013-01-01

    Highlights: • Film waste from packaging is a common waste, a fraction of which is not recyclable. • Gasification can make use of the high energy value of the non-recyclable fraction. • This waste and two reference polymers were gasified in a bubbling bed reactor. • This experimental research proves technical feasibility of the process. • It also analyzes impact of composition and ER on the performance of the plant. - Abstract: The use of plastic bags and film packaging is very frequent in manifold sectors and film waste is usually present in different sources of municipal and industrial wastes. A significant part of it is not suitable for mechanical recycling but could be safely transformed into a valuable gas by means of thermal valorization. In this research, the gasification of film wastes has been experimentally investigated through experiments in a fluidized bed reactor of two reference polymers, polyethylene and polypropylene, and actual post-consumer film waste. After a complete experimental characterization of the three materials, several gasification experiments have been performed to analyze the influence of the fuel and of equivalence ratio on gas production and composition, on tar generation and on efficiency. The experiments prove that film waste and analogue polymer derived wastes can be successfully gasified in a fluidized bed reactor, yielding a gas with a higher heating value in a range from 3.6 to 5.6 MJ/m 3 and cold gas efficiencies up to 60%

  5. Mechanical, Thermal and Surface Investigations of Chitosan/Agar/PVA Ternary Blended Films

    Directory of Open Access Journals (Sweden)

    Esam A. El-Hefian

    2011-01-01

    Full Text Available The mechanical and thermal properties of chitosan/agar/poly vinyl alcohol (CS/AG/PVA ternary blended films having various proportions considering chitosan as the main component were investigated. The various variables static water contact angle such as contact angle, drop base area, drop volume and drop height was also studied in correlation with the variation of time. Results obtained from mechanical measurements showed a noticeable increase in the tensile strength (TS coincided with a sharp decrease in elongation percent at break (E% of blended films with increasing agar and PVA contents. The DSC results prevailed the development of an interaction between chitosan individual components: agar and PVA. Moreover, an enhancement of the wettability of the blends was obtained with increasing agar and PVA contents. It was also found that the pure CS film and the blended films with 90/05/05 and 80/10/10 compositions were more affected by time than blended films with other compositions when the contact angle, the drop height and the drop length were studied as a function of time. In addition, when the drop is initially placed on the substrate, the drop area and the drop volume of all films remained almost constant up to a certain time after which they showed a slight difference with the elapse of time.

  6. Use of a laser-induced fluorescence thermal imaging system for film cooling heat transfer measurement

    Energy Technology Data Exchange (ETDEWEB)

    Chyu, M.K. [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    1995-10-01

    This paper describes a novel approach based on fluorescence imaging of thermographic phosphor that enables the simultaneous determination of both local film effectiveness and local heat transfer on a film-cooled surface. The film cooling model demonstrated consists of a single row of three discrete holes on a flat plate. The transient temperature measurement relies on the temperature-sensitive fluorescent properties of europium-doped lanthanum oxysulfide (La{sub 2}O{sub 2}S:EU{sup 3+}) thermographic phosphor. A series of full-field surface temperatures, mainstream temperatures, and coolant film temperatures were acquired during the heating of a test surface. These temperatures are used to calculate the heat transfer coefficients and the film effectiveness simultaneously. Because of the superior spatial resolution capability for the heat transfer data reduced from these temperature frames, the laser-induced fluorescence (LIF) imaging system, the present study observes the detailed heat transfer characteristics over a film-protected surface. The trend of the results agrees with those obtained using other conventional thermal methods, as well as the liquid crystal imaging technique. One major advantage of this technique is the capability to record a large number of temperature frames over a given testing period. This offers multiple-sample consistency.

  7. Chitosan-Starch Films with Natural Extracts: Physical, Chemical, Morphological and Thermal Properties

    Directory of Open Access Journals (Sweden)

    Jessica I. Lozano-Navarro

    2018-01-01

    Full Text Available The aim of this study is to analyze the properties of a series of polysaccharide composite films, such as apparent density, color, the presence of functional groups, morphology, and thermal stability, as well as the correlation between them and their antimicrobial and optical properties. Natural antioxidants such as anthocyanins (from cranberry; blueberry and pomegranate; betalains (from beetroot and pitaya; resveratrol (from grape; and thymol and carvacrol (from oregano were added to the films. Few changes in the position and intensity of the FTIR spectra bands were observed despite the low content of extract added to the films. Due to this fact, the antioxidants were extracted and identified by spectroscopic analysis; and they were also quantified using the Folin-Denis method and a gallic acid calibration curve, which confirmed the presence of natural antioxidants in the films. According to the SEM analysis, the presence of natural antioxidants has no influence on the film morphology because the stretch marks and white points that were observed were related to starch presence. On the other hand, the TGA analysis showed that the type of extract influences the total weight loss. The overall interpretation of the results suggests that the use of natural antioxidants as additives for chitosan-starch film preparation has a prominent impact on most of the critical properties that are decisive in making them suitable for food-packing applications.

  8. Chitosan-Starch Films with Natural Extracts: Physical, Chemical, Morphological and Thermal Properties

    Science.gov (United States)

    Díaz-Zavala, Nancy P.; Melo-Banda, José A.; García-Alamilla, Ricardo; Martínez-Hernández, Ana L.; Zapién-Castillo, Samuel

    2018-01-01

    The aim of this study is to analyze the properties of a series of polysaccharide composite films, such as apparent density, color, the presence of functional groups, morphology, and thermal stability, as well as the correlation between them and their antimicrobial and optical properties. Natural antioxidants such as anthocyanins (from cranberry; blueberry and pomegranate); betalains (from beetroot and pitaya); resveratrol (from grape); and thymol and carvacrol (from oregano) were added to the films. Few changes in the position and intensity of the FTIR spectra bands were observed despite the low content of extract added to the films. Due to this fact, the antioxidants were extracted and identified by spectroscopic analysis; and they were also quantified using the Folin-Denis method and a gallic acid calibration curve, which confirmed the presence of natural antioxidants in the films. According to the SEM analysis, the presence of natural antioxidants has no influence on the film morphology because the stretch marks and white points that were observed were related to starch presence. On the other hand, the TGA analysis showed that the type of extract influences the total weight loss. The overall interpretation of the results suggests that the use of natural antioxidants as additives for chitosan-starch film preparation has a prominent impact on most of the critical properties that are decisive in making them suitable for food-packing applications. PMID:29329275

  9. 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.

  10. Dynamics of ultrathin metal films on amorphous substrates under fast thermal processing

    International Nuclear Information System (INIS)

    Favazza, Christopher; Kalyanaraman, Ramki; Sureshkumar, Radhakrishna

    2007-01-01

    A mathematical model is developed to analyze the growth/decay rate of surface perturbations of an ultrathin metal film on an amorphous substrate (SiO 2 ). The formulation combines the approach of Mullins [W. W. Mullins, J. Appl. Phys. 30, 77 (1959)] for bulk surfaces, in which curvature-driven mass transport and surface deformation can occur by surface/volume diffusion and evaporation-condensation processes, with that of Spencer et al. [B. J. Spencer, P. W. Voorhees, and S. H. Davis, Phys. Rev. Lett. 67, 26 (1991)] to describe solid-state transport in thin films under epitaxial strain. Modifications of the Mullins model to account for thin-film boundary conditions result in qualitatively different dispersion relationships especially in the limit as kh o o is the unperturbed film height. The model is applied to study the relative rate of solid-state mass transport as compared to that of liquid phase dewetting in a thin film subjected to a fast thermal pulse. Specifically, we have recently shown that multiple cycles of nanosecond (ns) pulsed laser melting and resolidification of ultrathin metal films on amorphous substrates can lead to the formation of various types of spatially ordered nanostructures [J. Trice, D. Thomas, C. Favazza, R. Sureshkumar, and R. Kalyanaraman, Phys. Rev. B 75, 235439 (2007)]. The pattern formation has been attributed to the dewetting of the thin film by a hydrodynamic instability. In such experiments the film is in the solid state during a substantial fraction of each thermal cycle. However, results of a linear stability analysis based on the aforementioned model suggest that solid-state mass transport has a negligible effect on morphological changes of the surface. Further, a qualitative analysis of the effect of thermoelastic stress, induced by the rapid temperature changes in the film-substrate bilayer, suggests that stress relaxation does not appreciably contribute to surface deformation. Hence, surface deformation caused by liquid

  11. Dynamics of ultrathin metal films on amorphous substrates under fast thermal processing

    Science.gov (United States)

    Favazza, Christopher; Kalyanaraman, Ramki; Sureshkumar, Radhakrishna

    2007-11-01

    A mathematical model is developed to analyze the growth/decay rate of surface perturbations of an ultrathin metal film on an amorphous substrate (SiO2). The formulation combines the approach of Mullins [W. W. Mullins, J. Appl. Phys. 30, 77 (1959)] for bulk surfaces, in which curvature-driven mass transport and surface deformation can occur by surface/volume diffusion and evaporation-condensation processes, with that of Spencer etal . [B. J. Spencer, P. W. Voorhees, and S. H. Davis, Phys. Rev. Lett. 67, 26 (1991)] to describe solid-state transport in thin films under epitaxial strain. Modifications of the Mullins model to account for thin-film boundary conditions result in qualitatively different dispersion relationships especially in the limit as kho≪1, where k is the wavenumber of the perturbation and ho is the unperturbed film height. The model is applied to study the relative rate of solid-state mass transport as compared to that of liquid phase dewetting in a thin film subjected to a fast thermal pulse. Specifically, we have recently shown that multiple cycles of nanosecond (ns) pulsed laser melting and resolidification of ultrathin metal films on amorphous substrates can lead to the formation of various types of spatially ordered nanostructures [J. Trice, D. Thomas, C. Favazza, R. Sureshkumar, and R. Kalyanaraman, Phys. Rev. B 75, 235439 (2007)]. The pattern formation has been attributed to the dewetting of the thin film by a hydrodynamic instability. In such experiments the film is in the solid state during a substantial fraction of each thermal cycle. However, results of a linear stability analysis based on the aforementioned model suggest that solid-state mass transport has a negligible effect on morphological changes of the surface. Further, a qualitative analysis of the effect of thermoelastic stress, induced by the rapid temperature changes in the film-substrate bilayer, suggests that stress relaxation does not appreciably contribute to surface

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

    KAUST Repository

    Jiang, Jie; Wang, Xinghui; Zhang, Qing; Li, Jingqi; Zhang, Xixiang

    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.

  13. Mechanical design of thin-film diamond crystal mounting apparatus with optimized thermal contact and crystal strain for coherence preservation x-ray optics

    Science.gov (United States)

    Shu, Deming; Shvydko, Yury; Stoupin, Stanislav; Kim, Kwang-Je

    2018-05-08

    A method and mechanical design for a thin-film diamond crystal mounting apparatus for coherence preservation x-ray optics with optimized thermal contact and minimized crystal strain are provided. The novel thin-film diamond crystal mounting apparatus mounts a thin-film diamond crystal supported by a thick chemical vapor deposition (CVD) diamond film spacer with a thickness slightly thicker than the thin-film diamond crystal, and two groups of thin film thermal conductors, such as thin CVD diamond film thermal conductor groups separated by the thick CVD diamond spacer. The two groups of thin CVD film thermal conductors provide thermal conducting interface media with the thin-film diamond crystal. A piezoelectric actuator is integrated into a flexural clamping mechanism generating clamping force from zero to an optimal level.

  14. Isothermal relaxation current and microstructure changes of thermally aged polyester films impregnated by epoxy resin

    Science.gov (United States)

    Jiang, Xiongwei; Sun, Potao; Peng, Qingjun; Sima, Wenxia

    2018-01-01

    In this study, to understand the effect of thermal aging on polymer films degradation, specimens of polyester films impregnated by epoxy resin with different thermal aging temperatures (80 and 130 °C) and aging times (500, 1600, 2400 and 3000 h) are prepared, then charge de-trapping properties of specimens are investigated via the isothermal relaxation current (IRC) measurement, the distributions of trap level and its corresponding density are obtained based on the modified IRC model. It is found that the deep trap density increases remarkably at the beginning of thermal aging (before 1600 h), but it decreases obviously as the aging degree increases. At elevated aging temperature and, in particular considering the presence of air gap between two-layer insulation, the peak densities of deep traps decrease more significant in the late period of aging. It can be concluded that it is the released energy from de-trapping process leads to the fast degradation of insulation. Moreover, after thermal aging, the microstructure changes of crystallinity and molecular structures are analyzed via the x-ray diffraction experiment and Fourier transform infrared spectrometer. The results indicate that the variation of the deep trap density is closely linked with the changes of microstructure, a larger interface of crystalline/amorphous phase, more defects and broken chains caused by thermal aging form higher deep trap density stored in the samples.

  15. Transient thermal protection of film covering circular aperture by sublimation and weak decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Havstad, Mark A.; Miles, Robin R.; Hsieh, Henry, E-mail: hsieh6@llnl.gov

    2015-03-15

    Highlights: • Precise sublimating layers can provide protection in transient thermal environments. • Sensitivity analysis shows that the uncertainty in properties has modest influence. • It is likely that methane layers are a good choice for IFE targets. - Abstract: Unwanted heating of sensitive surfaces in harsh thermal environments can be prevented by precise application of sacrificial materials such as sublimation layers and pyrolyzing films. The use of sublimation for the protection of circular polyimide membranes subjected to brief (∼100 ms) heating by infrared radiation and hot (6000 K) inert gas convection is analyzed. Selection of sublimation material and sublimation layer and membrane thickness is considered with emphasis on providing sufficient thermal protection yet negligible unwanted material remaining at the end of a specified heating period. Though the analysis here is general, the motivation is protection of the polyimide films covering the laser entrance holes on IFE (inertial fusion energy) hohlraums being injected into the hot gas (xenon) protecting IFE reactor chambers. Both one and two dimensional thermal models are used to develop a robust thermal concept. Sensitivity analyses (SA) methods are exercised to show where the design may be vulnerable and which input parameters have the greatest effect on performance and likelihood of success. For the design and conditions considered, methane sublimating layers are probably preferred over xenon or pentane.

  16. Characteristics of rapid-thermal-annealed LiCoO2 cathode film for an all-solid-state thin film microbattery

    International Nuclear Information System (INIS)

    Kim, Han-Ki; Yoon, Young Soo

    2004-01-01

    We report on the fabrication of a LiCoO 2 film for an all-solid-state thin film microbattery by using a rapid-thermal-annealing (RTA) process. The LiCoO 2 films were grown by rf magnetron sputtering using a synthesized LiCoO 2 target in a [O 2 /(Ar+O 2 )] ratio of 10%. Scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES) analysis results showed that the surface layer on the as-deposited LiCoO 2 film was completely removed by rapid thermal annealing process in oxygen ambient for 20 min. In addition, the thin film microbattery fabricated with the annealed LiCoO 2 film shows fairly stable cyclability with a specific discharge capacity of 56.49 μAh/cm2 μm. These results show the possibility of the RTA LiCoO 2 film and rapid thermal annealing process being a promising cathode material and annealing process for thin film microbatteries, respectively

  17. Rapid thermal annealing of Ti-rich TiNi thin films: A new approach to fabricate patterned shape memory thin films

    International Nuclear Information System (INIS)

    Motemani, Y.; Tan, M.J.; White, T.J.; Huang, W.M.

    2011-01-01

    This paper reports the rapid thermal annealing (RTA) of Ti-rich TiNi thin films, synthesized by the co-sputtering of TiNi and Ti targets. Long-range order of aperiodic alloy could be achieved in a few seconds with the optimum temperature of 773 K. Longer annealing (773 K/240 s), transformed the film to a poorly ordered vitreous phase, suggesting a novel method for solid state amorphization. Reitveld refinement analyses showed significant differences in structural parameters of the films crystallized by rapid and conventional thermal annealing. Dependence of the elastic modulus on the valence electron density (VED) of the crystallized films was studied. It is suggested that RTA provides a new approach to fabricate patterned shape memory thin films.

  18. 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.

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

    KAUST Repository

    Salas Villaseñ or, Ana L.; Mejia, Israel I.; Sotelo-Lerma, Mé rida; Guo, Zaibing; Alshareef, Husam N.; Quevedo-Ló pez, Manuel Angel Quevedo

    2014-01-01

    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.

  20. Spin-pump-induced spin transport in a thermally evaporated pentacene film

    Energy Technology Data Exchange (ETDEWEB)

    Tani, Yasuo; Shikoh, Eiji, E-mail: shikoh@elec.eng.osaka-cu.ac.jp [Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Teki, Yoshio [Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan)

    2015-12-14

    We report the spin-pump-induced spin transport properties of a pentacene film prepared by thermal evaporation. In a palladium(Pd)/pentacene/Ni{sub 80}Fe{sub 20} tri-layer sample, a pure spin-current is generated in the pentacene layer by the spin-pumping of Ni{sub 80}Fe{sub 20}, which is independent of the conductance mismatch problem in spin injection. The spin current is absorbed into the Pd layer, converted into a charge current with the inverse spin-Hall effect in Pd, and detected as an electromotive force. This is clear evidence for the pure spin current at room temperature in pentacene films prepared by thermal evaporation.

  1. 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.

  2. Dynamics of a thermally driven film climbing the outside of a vertical cylinder.

    Science.gov (United States)

    Smolka, Linda B

    2017-10-01

    The dynamics of a film climbing the outside of a vertical cylinder under the competing effects of a thermally driven surface tension gradient and gravity is examined through numerical simulations of a thin-film model for the film height. The model, including boundary conditions, depends on three parameters, the scaled cylinder radius R[over ̂], the upstream film height h_{∞}, and the downstream precursor film thickness b, and reduces to the model for Marangoni driven film climbing a vertical plate in the limit R[over ̂]→∞. The axisymmetric advancing front displays dynamics similar to that found along a vertical plate where, depending on h_{∞}, the film forms a single Lax shock, an undercompressive double shock, or a rarefaction-undercompressive shock. A linear stability analysis of the Lax shock reveals the number of fingers that form along the contact line increases linearly with cylinder circumference while no fingers form for sufficiently small cylinders (below R[over ̂]≈1.15 when b=0.1). The substrate curvature controls the height of the Lax shock, bounds on h_{∞} that define the three distinct solutions, and the maximum growth rate of contact line perturbations to the Lax shock when R[over ̂]=O(1), whereas the three solutions and the stability of the Lax shock converge to the behavior one observes on a vertical plate when R[over ̂]≥O(10). An energy analysis reveals that the azimuthal curvatures of the base state and perturbation, which arise from the annular geometry of the film, promote instability of the advancing contact line.

  3. Through-thickness thermal conductivity enhancement of graphite film/epoxy composite via short duration acidizing modification

    Science.gov (United States)

    Wang, Han; Wang, Shaokai; Lu, Weibang; Li, Min; Gu, Yizhou; Zhang, Yongyi; Zhang, Zuoguang

    2018-06-01

    Graphite films have excellent in-plane thermal conductivity but extremely low through-thickness thermal conductivity because of their intrinsic inter-layer spaces. To improve the inter-layer heat transfer of graphite films, we developed a simple interfacial modification with a short duration mixed-acid treatment. The effects of the mixture ratio of sulfuric and nitric acids and treatment time on the through-thickness thermal properties of graphite films were studied. The modification increased the through-thickness thermal conductivity by 27% and 42% for the graphite film and its composite, respectively. X-ray photoelectron spectroscopy, X-ray powder diffraction, and scanning electron microscopy results indicated that the acidification process had two competing effects: the positive contribution made by the enhanced interaction between the graphite layers induced by the functional groups and the negative effect from the destruction of the graphite layers. As a result, an optimal acidification method was found to be sulfuric/nitric acid treatment with a mixture ratio of 3:1 for 15 min. The resultant through-thickness thermal conductivity of the graphite film could be improved to 0.674 W/mK, and the corresponding graphite/epoxy composite shows a through-thickness thermal conductivity of 0.587 W/mK. This method can be directly used for graphite films and their composite fabrication to improve through-thickness thermal conductivity.

  4. Thermal behaviour and corrosion resistance of nano-ZnO/polyurethane film

    Science.gov (United States)

    Virgawati, E.; Soegijono, B.

    2018-03-01

    Hybrid materials Nano-ZnO/polyurethane film was prepared with different zinc oxide (ZnO) content in polyurethane as a matrix. The film was deposited on low carbon steel plate using high volume low pressure (HVLP) method. To observe thermal behaviour of the film, the sample was investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Fourier transform infrared spectroscopy (FTIR) was used to see whether any chemical reaction of ZnO in polyurethane occured. TGA and FTIR results showed that the decomposition temperature shifted to a higher point and the chemical reaction of zinc oxide in polyurethane occurred. The surface morphology changed and the corrosion resistance increased with an increase of ZnO content

  5. Influence of multi-depositions on the final properties of thermally evaporated TlBr films

    International Nuclear Information System (INIS)

    Destefano, N.; Mulato, M.

    2010-01-01

    Thallium bromide is a promising candidate material for photodetectors in medical imaging systems. This work investigates the structural, optical and electrical properties of thermally evaporated TlBr films. The main fabrication parameter is the number of depositions. The use of sequential runs is aimed to increase the thickness of the films, as necessary, for technological applications. We deposited films using one-four runs, that led to maximum thickness of about 50 μm. Crystallographic and morphological changes were observed with varying deposition runs. Nevertheless, the optical gap and electrical resistivity in the dark remained constant at about 2.85 eV and 10 9 Ω cm, respectively. Thicker samples have a larger ratio of photo-to-dark signal under medical X-ray exposure, with a larger linear region as a function of applied voltage. The results are discussed aiming at future technological applications in medical imaging.

  6. Thermal stability of atomic layer deposition Al2O3 film on HgCdTe

    Science.gov (United States)

    Zhang, P.; Sun, C. H.; Zhang, Y.; Chen, X.; He, K.; Chen, Y. Y.; Ye, Z. H.

    2015-06-01

    Thermal stability of Atomic Layer Deposition Al2O3 film on HgCdTe was investigated by Al2O3 film post-deposition annealing treatment and Metal-Insulator-Semiconductor device low-temperature baking treatment. The effectiveness of Al2O3 film was evaluated by measuring the minority carrier lifetime and capacitance versus voltage characteristics. After annealing treatment, the minority carrier lifetime of the HgCdTe sample presented a slight decrease. Furthermore, the fixed charge density and the slow charge density decreased significantly in the annealed MIS device. After baking treatment, the fixed charge density and the slow charge density of the unannealed and annealed MIS devices decreased and increased, respectively.

  7. Electrical transport properties of thermally evaporated phthalocyanine (H 2Pc) thin films

    Science.gov (United States)

    El-Nahass, M. M.; Farid, A. M.; Attia, A. A.; Ali, H. A. M.

    2006-08-01

    Thin films of H 2Pc of various thicknesses have been deposited onto glass substrates using thermal evaporation technique at room temperature. The dark electrical resistivity measurements were carried out at different temperatures in the range 298-473 K. An estimation of mean free path ( lo) of charge carriers in H 2Pc thin films was attempted. Measurements of thermoelectric power confirm that H 2Pc thin films behave as a p-type semiconductor. The current density-voltage characteristics of Au/H 2Pc/Au at room temperature showed ohmic conduction mechanism at low voltages. At higher voltages the space-charge-limited conduction (SCLC) accompanied by an exponential trap distribution was dominant. The temperature dependence of current density allows the determination of some essential parameters such as the hole mobility ( μh), the total trap concentration ( Nt), the characteristic temperature ( Tt) and the trap density P( E).

  8. Experimental study on surface wrinkling of silicon monoxide film on compliant substrate under thermally induced loads

    Science.gov (United States)

    Li, Chuanwei; Kong, Yingxiao; Jiang, Wenchong; Wang, Zhiyong; Li, Linan; Wang, Shibin

    2017-06-01

    The wrinkling of a silicon monoxide thin film on a compliant poly(dimethylsiloxane) (PDMS) substrate structure was experimentally investigated in this study. The self-expansion effect of PDMS during film deposition was utilized to impose a pretensile strain on the structure through a specially made fixture. A laser scanning confocal microscope (LSCM) system with an in situ heating stage was employed for the real-time measurement. The Young’s modulus of the silicon monoxide thin film as well as the PDMS substrate was measured on the basis of the elasticity theory. Moreover, the effects of temperature variations on geometric parameters in the postbuckling state, such as wavelength and amplitude, were analyzed. It was proved that wavelength is relatively immune to thermal loads, while amplitude is much more sensitive.

  9. Effect of grain alignment on interface trap density of thermally oxidized aligned-crystalline silicon films

    Science.gov (United States)

    Choi, Woong; Lee, Jung-Kun; Findikoglu, Alp T.

    2006-12-01

    The authors report studies of the effect of grain alignment on interface trap density of thermally oxidized aligned-crystalline silicon (ACSi) films by means of capacitance-voltage (C-V) measurements. C-V curves were measured on metal-oxide-semiconductor (MOS) capacitors fabricated on ⟨001⟩-oriented ACSi films on polycrystalline substrates. From high-frequency C-V curves, the authors calculated a decrease of interface trap density from 2×1012to1×1011cm-2eV-1 as the grain mosaic spread in ACSi films improved from 13.7° to 6.5°. These results demonstrate the effectiveness of grain alignment as a process technique to achieve significantly enhanced performance in small-grained (⩽1μm ) polycrystalline Si MOS-type devices.

  10. Metal Chloride Induced Formation of Porous Polyhydroxybutyrate (PHB) Films: Morphology, Thermal Properties and Crystallinity

    Science.gov (United States)

    Tan, W. L.; Yaakob, N. N.; Zainal Abidin, A.; Abu Bakar, M.; Abu Bakar, N. H. H.

    2016-06-01

    Polyhydroxybutyrate (PHB) films with highly porous structures were synthesized using a one phase system comprising of metal chloride/methanol/PHB/chloroform (MCl2/CH3OH/PHB/CHCl3). SEM analyses confirmed that the MCl2 (where M = Cu2+ or Ni2+) induced porous structures with pore sizes ranging from 0.3 - 2.0 μm. The average pore size increased with the increasing MCl2 content. There existed weak physical interactions between the PHB chains and MCl2 as revealed by FTIR and NMR spectroscopies. The residue of MCl2 in the porous PHB film does not exert significant influence on the thermal stability of PHB. Nevertheless, the crystallinity of the prepared film is enhanced, as MCl2 acts as the nucleation sites to promote the growth of spherullites.

  11. Coupling analysis of frictional heat of fluid film and thermal deformation of mechanical seal end faces

    International Nuclear Information System (INIS)

    Zhou Jianfeng; Gu Boqin

    2007-01-01

    The heat transfer model of the rotating ring and the stationary ring of mechanical seal was built. The method to calculate the frictional heat that transferred by the rings was given. the coupling analysis of the frictional heat of fluid film and thermal deformation of end faces was carried out by using FEA and BP ANN, and the relationship among the rotational speed ω, the fluid film thickness h i on the inner diameter of sealing face and the radial separation angle β of deformed end faces was obtained. Corresponding to a given ω, h i and β can be obtained by the equilibrium condition between the closing force and the bearing force of fluid film. The relationship between the leakage rate and the closing force was analyzed, and the fundamental of controlling the leakage rate by regulating the closing force was also discussed. (authors)

  12. The effect of thermal annealing on pentacene thin film transistor with micro contact printing.

    Science.gov (United States)

    Shin, Hong-Sik; Yun, Ho-Jin; Baek, Kyu-Ha; Ham, Yong-Hyun; Park, Kun-Sik; Kim, Dong-Pyo; Lee, Ga-Won; Lee, Hi-Deok; Lee, Kijun; Do, Lee-Mi

    2012-07-01

    We used micro contact printing (micro-CP) to fabricate inverted coplanar pentacene thin film transistors (TFTs) with 1-microm channels. The patterning of micro-scale source/drain electrodes without etch process was successfully achieved using Polydimethylsiloxane (PDMS) elastomer stamp. We used the Ag nano particle ink as an electrode material, and the sheet resistance and surface roughness of the Ag electrodes were effectively reduced with the 2-step thermal annealing on a hotplate, which improved the mobility, the on-off ratio, and the subthreshold slope (SS) of the pentacene TFTs. In addition, the device annealing on a hotplate in a N2 atmosphere for 30 sec can enhance the off-current and the mobility properties of OTFTs without damaging the pentacene thin films and increase the adhesion between pentacene and dielectric layer (SiO2), which was investigated with the pentacene films phase change of the XRD spectrum after device annealing.

  13. 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......, to significantly decrease the distribution of crystal orientation obtained after crystallization using the thermal gradient technique....

  14. 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...

  15. 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.

  16. Study of 'liquid gold' coatings: Thermal decomposition and formation of metallic thin films

    International Nuclear Information System (INIS)

    Deram, V.; Turrell, S.; Darque-Ceretti, E.; Aucouturier, M.

    2006-01-01

    Organo-metallic solutions called liquid gold are largely used to obtain thin gilded films which are employed for decorative, technological and functional uses. However, these films often prove to be fragile with respect to use, resulting in loss of brilliance or even eventual film removal. An understanding of the behaviour of the layers requires good knowledge of the materials themselves. The present work was undertaken to better understand the evolution of the structural properties of liquid gold as it undergoes heat-processing. Accordingly, we followed the thermal decomposition processes of liquid gold coatings and the formation of the gilded metal layer using a combination of experimental techniques. First, thermal analyses coupled with mass spectrometry and infrared spectroscopy gave information concerning the decomposition of the organic medium. It has been found that the process of film formation can be decomposed into three steps, the second of which is an abrupt transition between 300 and 350 deg. C. Details on this transition have been obtained using real-time X-ray Diffraction and Rutherford Backscattering Spectrometry. Above 350 deg. C, the microstructure of the coating is reorganized to obtain a final layer which contains particles, of the size of a few hundreds nanometers, as shown by Transmission Electron Microscopy

  17. 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)

  18. 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.

  19. Effect of thermal history on the structure of chemically and vapor deposited silver films on glass

    International Nuclear Information System (INIS)

    Shelby, J.E.; Nichols, M.C.; Smith, D.K. Jr.; Vitko, J. Jr.

    1981-01-01

    The observation of silver agglomeration in second surface mirrors used for solar applications has emphasized consideration of the effect of thermal history on the optical properties of mirrors. Thermal history effects may arise from the processing of mirrors, the application of protective coatings, or from outdoor exposure. Mirrors may be subject to elevated temperatures (T less than or equal to 400 0 C) for short periods of time, or to low temperatures (T less than or equal to 60 0 C) for long (less than or equal to 30 years) periods of time. Although a significant amount of work has been done on thermally driven agglomeration of silver films, most of these studies have been restricted to vapor deposited films on vitreous silica. Large area reflectors, such as those used in heliostats, will almost certainly be deposited by commercial chemical methods on substrates of soda-lime-silicate or other glasses which differ considerably from vitreous silica in composition and properties. The present study addresses the effect of this change in deposition technique and substrate on silver agglomeration. These problems were studied by optical and scanning electron microscopy, reflectometry, and x-ray diffraction. The results indicate that both the method used to deposit the silver and the type of glass affect the agglomeration process and the character of the reflective film

  20. Cuprous oxide thin films prepared by thermal oxidation of copper layer. Morphological and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Karapetyan, Artak, E-mail: karapetyan@cinam.univ-mrs.fr [Aix Marseille Université, CINaM, 13288, Marseille (France); Institute for Physical Research of NAS of Armenia, Ashtarak-2 0203 (Armenia); Reymers, Anna [Russian-Armenian (Slavonic) University, H.Emin st.123, Yerevan 375051 (Armenia); Giorgio, Suzanne; Fauquet, Carole [Aix Marseille Université, CINaM, 13288, Marseille (France); Sajti, Laszlo [Laser Zentrum Hannover e.V. Hollerithallee 8, 30419 Hannover (Germany); Nitsche, Serge [Aix Marseille Université, CINaM, 13288, Marseille (France); Nersesyan, Manuk; Gevorgyan, Vladimir [Russian-Armenian (Slavonic) University, H.Emin st.123, Yerevan 375051 (Armenia); Marine, Wladimir [Aix Marseille Université, CINaM, 13288, Marseille (France)

    2015-03-15

    Structural and optical characterization of crystalline Cu{sub 2}O thin films obtained by thermal oxidation of Cu films at two different temperatures 800 °C and 900 °C are investigated in this work. X-ray diffraction measurements indicate that synthesized films consist of single Cu{sub 2}O phase without any interstitial phase and show a nano-grain structure. Scanning Electron Microscopy observations indicate that the Cu{sub 2}O films have a micro-scale roughness whereas High Resolution Transmission Electron Microscopy highlights that the nanocrystalline structure is formed by superposition of nearly spherical nanocrystals smaller than 30 nm. Photoluminescence spectra of these films exhibit at room temperature two well-resolved emission peaks at 1.34 eV due to defects energy levels and at 1.97 eV due to phonon-assisted recombination of the 1s orthoexciton in both film series. Emission characteristics depending on the laser power is deeply investigated to determine the origin of recorded emissions. Time-integrated spectra of the 1s orthoexciton emission reveals the presence of oxygen defects below the conduction band edge under non-resonant two-photon excitation using a wide range of excitations wavelengths. Optical absorption coefficients at room temperature are obtained from an accurate analysis of their transmission and reflection spectra, whereas the optical band gap energy is estimated at about 2.11 eV. Results obtained are of high relevance especially for potential applications in semiconductor devices such as solar cells, optical sources and detectors. - Highlights: • Nanostructured Cu{sub 2}O thin films were synthesized by thermal oxidation of Cu films. • The PL spectra of nanostructured thin films revealed two well-resolved emission peaks. • The PL properties were investigated under a broad range of experimental conditions. • Inter-band transition in the infrared range has been associated to V{sub Cu} and V{sub O} vacancies. • Absorption

  1. Formation of VO{sub 2} by rapid thermal annealing and cooling of sputtered vanadium thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ba, Cheikhou O. F., E-mail: cheikhou.ba.1@ulaval.ca; Fortin, Vincent; Bah, Souleymane T.; Vallée, Réal [Centre d' optique, photonique et laser (COPL), Université Laval, Québec G1V 0A6 (Canada); Pandurang, Ashrit [Thin Films and Photonics Research Group (GCMP), Department of Physics and Astronomy, Université de Moncton, Moncton, New Brunswick E1A 3E9 (Canada)

    2016-05-15

    Sputtered vanadium-rich films were subjected to rapid thermal annealing-cooling (RTAC) in air to produce vanadium dioxide (VO{sub 2}) thin films with thermochromic switching behavior. High heating and cooling rates in the thermal oxidation process provided an increased ability to control the film's microstructure. X-ray diffraction patterns of the films revealed less intense VO{sub 2} peaks compared to traditional polycrystalline samples fabricated with a standard (slower) cooling time. Such films also exhibit a high optical switching reflectance contrast, unlike the traditional polycrystalline VO{sub 2} thin films, which show a more pronounced transmittance switching. The authors find that the RTAC process stabilizes the VO{sub 2} (M2) metastable phase, enabling a rutile-semiconductor phase transition (R-M2), followed by a semiconductor–semiconductor phase transition (M2-M1).

  2. Laser irradiation and thermal treatment inducing selective crystallization in Sb2O3-Sb2S3 glassy films

    Science.gov (United States)

    Avila, L. F.; Pradel, A.; Ribeiro, S. J. L.; Messaddeq, Y.; Nalin, M.

    2015-02-01

    The influence of both thermal treatment and laser irradiation on the structural and optical properties of films in the Sb2O3-Sb2S3 system was investigated. The films were prepared by RF-sputtering using glass compositions as raw materials. Irreversible photodarkening effect was observed after exposure the films to a 458 nm solid state laser. It is shown, for the first time, the use of holographic technique to measure "in situ", simultaneously and independently, the phase and amplitude modulations in glassy films. The films were also photo-crystallized and analysed "in situ" using a laser coupled to a micro-Raman equipment. Results showed that Sb2S3 crystalline phase was obtained after irradiation. The effect of thermal annealing on the structure of the films was carried out. Different from the result obtained by irradiation, thermal annealing induces the crystallization of the Sb2O3 phase. Photo and thermal induced effects on films were studied using UV-Vis and Raman spectroscopy, atomic force microscopy (AFM), thermal analysis (DSC), X-ray diffraction, scanning electron microscopy (MEV) and energy-dispersive X-ray spectroscopy (EDX).

  3. Physical and structural properties and thermal behaviour of starch-poly(ɛ-caprolactone) blend films for food packaging

    OpenAIRE

    Ortega Toro, Rodrigo; Contreras, Jessica; Talens Oliag, Pau; Chiralt A.

    2015-01-01

    Structural and physical properties (barrier, mechanical, and optical properties) and thermal behaviour of corn starch-PCL blend films, containing glycerol as plasticizer, obtained by compression moulding, at 160 °C and 130 bars, were studied. The stability on the films properties was also evaluated. Blend films showed phase separation of the polymers in a heterogeneous matrix with starch rich regions and PCL rich regions. Nevertheless, a small miscibility of PCL in the starch phase was detec...

  4. 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

  5. Semiconducting Properties of Nanostructured Amorphous Carbon Thin Films Incorporated with Iodine by Thermal Chemical Vapor Deposition

    Science.gov (United States)

    Kamaruzaman, Dayana; Ahmad, Nurfadzilah; Annuar, Ishak; Rusop, Mohamad

    2013-11-01

    Nanostructured iodine-post doped amorphous carbon (a-C:I) thin films were prepared from camphor oil using a thermal chemical vapor deposition (TCVD) technique at different doping temperatures. The structural properties of the films were studied by field-emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), Raman, and Fourier transform infrared (FTIR) studies. FESEM and EDS studies showed successful iodine doping. FTIR and Raman studies showed that the a-C:I thin films consisted of a mixture of sp2- and sp3-bonded carbon atoms. The optical and electrical properties of a-C:I thin films were determined by UV-vis-NIR spectroscopy and current-voltage (I-V) measurement respectively. The optical band gap of a-C thin films decreased upon iodine doping. The highest electrical conductivity was found at 400 °C doping. Heterojunctions are confirmed by rectifying the I-V characteristics of an a-C:I/n-Si junction.

  6. Thermal stability of tungsten sub-nitride thin film prepared by reactive magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.X. [School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou, 730050 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730050 (China); Wu, Y.Z., E-mail: youzhiwu@163.com [School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou, 730050 (China); Mu, B. [College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou, 730050 (China); Qiao, L. [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730050 (China); Li, W.X.; Li, J.J. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, P., E-mail: pengwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730050 (China)

    2017-03-15

    Tungsten sub-nitride thin films deposited on silicon samples by reactive magnetron sputtering were used as a model system to study the phase stability and microstructural evolution during thermal treatments. XRD, SEM&FIB, XPS, RBS and TDS were applied to investigate the stability of tungsten nitride films after heating up to 1473 K in vacuum. At the given experimental parameters a 920 nm thick crystalline film with a tungsten and nitrogen stoichiometry of 2:1 were achieved. The results showed that no phase and microstructure change occurred due to W{sub 2}N film annealing in vacuum up to 973 K. Heating up to 1073 K led to a partial decomposition of the W{sub 2}N phase and the formation of a W enrichment layer at the surface. Increasing the annealing time at the same temperature, the further decomposition of the W{sub 2}N phase was negligible. The complete decomposition of W{sub 2}N film happened as the temperature reached up to 1473 K.

  7. 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

  8. Thermal valorization of post-consumer film waste in a bubbling bed gasifier.

    Science.gov (United States)

    Martínez-Lera, S; Torrico, J; Pallarés, J; Gil, A

    2013-07-01

    The use of plastic bags and film packaging is very frequent in manifold sectors and film waste is usually present in different sources of municipal and industrial wastes. A significant part of it is not suitable for mechanical recycling but could be safely transformed into a valuable gas by means of thermal valorization. In this research, the gasification of film wastes has been experimentally investigated through experiments in a fluidized bed reactor of two reference polymers, polyethylene and polypropylene, and actual post-consumer film waste. After a complete experimental characterization of the three materials, several gasification experiments have been performed to analyze the influence of the fuel and of equivalence ratio on gas production and composition, on tar generation and on efficiency. The experiments prove that film waste and analogue polymer derived wastes can be successfully gasified in a fluidized bed reactor, yielding a gas with a higher heating value in a range from 3.6 to 5.6 MJ/m3 and cold gas efficiencies up to 60%. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Role of thermal stresses on pulsed laser irradiation of thin films under conditions of microbump formation and nonvaporization forward transfer

    Science.gov (United States)

    Meshcheryakov, Yuri P.; Shugaev, Maxim V.; Mattle, Thomas; Lippert, Thomas; Bulgakova, Nadezhda M.

    2013-11-01

    This paper presents a theoretical analysis of the processes in thin solid films irradiated by short and ultrashort laser pulses in the regimes of film structuring and laser-induced forward transfer. The regimes are considered at which vaporization of the film materials is insignificant and film dynamics is governed mainly by mechanical processes. Thermoelastoplastic modeling has been performed for a model film in one- and two-dimensional geometries. A method has been proposed to estimate the height of microbumps produced by nanosecond laser irradiation of solid films. Contrary to femtosecond laser pulses, in nanosecond pulse regimes, stress waves across the film are weak and cannot induce film damage. The main role in laser-induced dynamics of irradiated films is played by radial thermal stresses which lead to the formation of a bending wave propagating along the film and drawing the film matter to the center of the irradiation spot. The bending wave dynamics depends on the hardness of the substrate underlying the film. The causes of the receiver substrate damage sometimes observed upon laser-induced forward transfer in the scheme of the direct contact between the film and the receiver are discussed.

  10. Tuning the surface chemistry of lubricant-derived phosphate thermal films: The effect of boron

    Energy Technology Data Exchange (ETDEWEB)

    Spadaro, F. [Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, CH-8093 Zurich (Switzerland); Rossi, A., E-mail: antonella.rossi@mat.ethz.ch [Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, CH-8093 Zurich (Switzerland); Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Cittadella Universitaria di Monserrato, I-09100, Cagliari (Italy); Lainé, E.; Woodward, P. [Enabling Research, Infineum UK Ltd., Milton Hill, Steventon, Oxfordshire OX13 6BD (United Kingdom); Spencer, N.D., E-mail: nicholas.spencer@mat.ethz.ch [Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Vladimir-Prelog-Weg 5, CH-8093 Zurich (Switzerland)

    2017-02-28

    Highlights: • The additives bulk interactions in “neat” blends at high temperatures is evaluated. • The competition among the different additives to react with air-oxidized steel surfaces under pure thermal condition is investigated. • Different thermal films are grown, their in depth-composition and thickness is determined by ARXPS. • A reaction mechanism is proposed for elucidating the composition of the thermals films. - Abstract: Understanding the interactions among the various additives in a lubricant is important because they can have a major influence on the performance of blends under tribological conditions. The present investigation is focused on the interactions occurring between ZnDTP and dispersant molecules in an oil formulation, and on their reactivity under purely thermal conditions in the presence of air-oxidized iron surfaces. Nuclear magnetic resonance spectroscopy (NMR) was performed on undiluted blends at different temperatures, while angle-resolved X-ray photoelectron spectroscopy (ARXPS) was exploited to investigate the surface reactivity on oxidized iron surfaces. The results indicate that the dispersant, generally added to blends for preventing the deposition of sludge, varnish and soot on the surface, might also inhibit the reaction of all other additives with the steel surface.

  11. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Marcelo M. Nobrega

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  12. Fabrication of 3D Microfluidic Devices by Thermal Bonding of Thin Poly(methyl methacrylate) Films

    KAUST Repository

    Perez, Paul

    2012-07-01

    The use of thin-film techniques for the fabrication of microfluidic devices has gained attention over the last decade, particularly for three-dimensional channel structures. The reasons for this include effective use of chip volume, mechanical flexibility, dead volume reduction, enhanced design capabilities, integration of passive elements, and scalability. Several fabrication techniques have been adapted for use on thin films: laser ablation and hot embossing are popular for channel fabrication, and lamination is widely used for channel enclosure. However, none of the previous studies have been able to achieve a strong bond that is reliable under moderate positive pressures. The present work aims to develop a thin-film process that provides design versatility, speed, channel profile homogeneity, and the reliability that others fail to achieve. The three building blocks of the proposed baseline were fifty-micron poly(methyl methacrylate) thin films as substrates, channel patterning by laser ablation, and device assembly by thermal-fusion bonding. Channel fabrication was characterized and tuned to produce the desired dimensions and surface roughness. Thermal bonding was performed using an adapted mechanical testing device and optimized to produce the maximum bonding strength without significant channel deformation. Bonding multilayered devices, incorporating conduction lines, and integrating various types of membranes as passive elements demonstrated the versatility of the process. Finally, this baseline was used to fabricate a droplet generator and a DNA detection chip based on micro-bead agglomeration. It was found that a combination of low laser power and scanning speed produced channel surfaces with better uniformity than those obtained with higher values. In addition, the implemented bonding technique provided the process with the most reliable bond strength reported, so far, for thin-film microfluidics. Overall, the present work proved to be versatile

  13. 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)

  14. Removal of Cd (II from Aqueous Media by Adsorption onto Chemically and Thermally Treated Rice Husk

    Directory of Open Access Journals (Sweden)

    María Camila Hoyos-Sánchez

    2017-01-01

    Full Text Available Chemically and thermally treated rice husks were evaluated as a potential decontaminant of toxic Cd (II in aqueous media. Rice husk (RH, a by-product from rice milling, was chemically treated with HCl and NaOH. Then, thermal treatments to 300, 500, and 700°C were applied. The chemical composition and morphological characteristics of RH were evaluated by different techniques. The specific surface area analysis of RH samples by BET nitrogen adsorption method provided specific surface areas ranging from 6 to 14 m2/g. SEM, FTIR, and EDX analyses of RH were carried out to determine the surface morphology, functional groups involved in metal binding mechanism, and C/O and C/Si ratios, respectively. The maximum Cd (II adsorption capacity was 28.27 mg/g at an optimum pH, 6.0. The kinetic studies revealed that adsorption process followed the pseudo-second-order kinetic model.

  15. [Gradient elevation of temperature startup experiment of thermophilic ASBR treating thermal-hydrolyzed sewage sludge].

    Science.gov (United States)

    Ouyang, Er-Ming; Wang, Wei; Long, Neng; Li, Huai

    2009-04-15

    Startup experiment was conducted for thermophilic anaerobic sequencing batch reactor (ASBR) treating thermal-hydrolyzed sewage sludge using the strategy of the step-wise temperature increment: 35 degrees C-->40 degrees C-->47 degrees C-->53 degrees C. The results showed that the first step-increase (from 35 degrees C to 40 degrees C) and final step-increase (from 47 degrees C to 53 degrees C) had only a slight effect on the digestion process. The second step-increase (from 40 degrees C to 47 degrees C) resulted in a severe disturbance: the biogas production, methane content, CODeffluent and microorganism all have strong disturbance. At the steady stage of thermophilic ASBR treating thermal-hydrolyzed sewage sludge, the average daily gas production, methane content, specific methane production (CH4/CODinfluent), TCOD removal rate and SCOD removal rate were 2.038 L/d, 72.0%, 188.8 mL/g, 63.8%, 83.3% respectively. The results of SEM and DGGE indicated that the dominant species are obviously different at early stage and steady stage.

  16. Voltammetric and impedance behaviours of surface-treated nano-crystalline diamond film electrodes

    International Nuclear Information System (INIS)

    Liu, F. B.; Jing, B.; Cui, Y.; Di, J. J.; Qu, M.

    2015-01-01

    The electrochemical performances of hydrogen- and oxygen-terminated nano-crystalline diamond film electrodes were investigated by cyclic voltammetry and AC impedance spectroscopy. In addition, the surface morphologies, phase structures, and chemical states of the two diamond films were analysed by scanning probe microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, respectively. The results indicated that the potential window is narrower for the hydrogen-terminated nano-crystalline diamond film than for the oxygen-terminated one. The diamond film resistance and capacitance of oxygen-terminated diamond film are much larger than those of the hydrogen-terminated diamond film, and the polarization resistances and double-layer capacitance corresponding to oxygen-terminated diamond film are both one order of magnitude larger than those corresponding to the hydrogen-terminated diamond film. The electrochemical behaviours of the two diamond film electrodes are discussed

  17. 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.

  18. 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.

  19. Effect of reactor radiation on the thermal conductivity of TREAT fuel

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Kun, E-mail: kunmo@anl.gov; Miao, Yinbin; Kontogeorgakos, Dimitrios C.; Connaway, Heather M.; Wright, Arthur E.; Yacout, Abdellatif M.

    2017-04-15

    The Transient Reactor Test Facility (TREAT) at the Idaho National Laboratory is resuming operations after more than 20 years in latency in order to produce high-neutron-flux transients for investigating transient-induced behavior of reactor fuels and their interactions with other materials and structures. A parallel program is ongoing to develop a replacement core in which the fuel, historically containing highly-enriched uranium (HEU), is replaced by low-enriched uranium (LEU). Both the HEU and prospective LEU fuels are in the form of UO{sub 2} particles dispersed in a graphite matrix, but the LEU fuel will contain a much higher volume of UO{sub 2} particles, which may create a larger area of interphase boundaries between the particles and the graphite. This may lead to a higher volume fraction of graphite exposed to the fission fragments escaping from the UO{sub 2} particles, and thus may induce a higher volume of fission-fragment damage on the fuel graphite. In this work, we analyzed the reactor-radiation induced thermal conductivity degradation of graphite-based dispersion fuel. A semi-empirical method to model the relative thermal conductivity with reactor radiation was proposed and validated based on the available experimental data. Prediction of thermal conductivity degradation of LEU TREAT fuel during a long-term operation was performed, with a focus on the effect of UO{sub 2} particle size on fission-fragment damage. The proposed method can be further adjusted to evaluate the degradation of other properties of graphite-based dispersion fuel.

  20. Characterization of Hf/Mg co-doped ZnO thin films after thermal treatments

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chih-Hung; Chung, Hantsun [Graduate Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan (China); Chen, Jian-Zhang, E-mail: jchen@ntu.edu.tw [Graduate Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan (China); Cheng, I-Chun, E-mail: iccheng@ntu.edu.tw [Graduate Institute of Photonics and Optoelectronics, Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-11-03

    Rf-sputtered Mg{sub 0.05}Zn{sub 0.95}O thin films become amorphous/nanocrystalline with the addition of hafnium oxide. All films (thickness: ∼ 100 nm) sputter-deposited from Hf{sub x}Mg{sub 0.05}Zn{sub 0.95−x}O targets are highly transparent (> 80%) from 400 to 800 nm. The Tauc bandgap ΔE (eV) increases with the Hf content. However, the bandgap decreases after thermal treatment. The reduction in the bandgap is positively correlated with the Hf content and annealing temperature. The residual stresses of films sputtered from Mg{sub 0.05}Zn{sub 0.95}O and Hf{sub 0.025}Mg{sub 0.05}Zn{sub 0.925}O targets are determined based on X-ray diffraction (XRD) data using a bi-axial stress model. The residual stresses of as-deposited films are compressive. As the annealing temperature increases, the residual stresses are relaxed and even become tensile. The bandgap narrowing after thermal treatment is attributed to the stress relaxation that changes the repulsion between the oxygen 2p and zinc 4s bands. Slight grain growth may also result in bandgap reduction because bandgap modification caused by the quantum confinement effect becomes significant in amorphous/nanocrystalline materials. The amorphous thin films reveal good thermal stability after 600 °C annealing for up to 2 h, as evidenced by the XRD and transmission spectra. - Highlights: • Thin films are sputtered from Hf{sub x}Mg{sub 0.05}Zn{sub 0.95−x}O targets at room temperature. • Bandgap increases with Hf content but decreases with post-annealing temperature. • Bandgap narrowing after annealing partly results from the relaxation of stresses. • Bandgap narrowing partly results from quantum confinement effect by nanomaterials. • Hf doping increases resistivity due to the lattice disorder and enlarged bandgap.

  1. 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

  2. Atomic Force Microscopy Based Thermal Lithography of Poly(tert-butyl acrylate) Block Copolymer Films for Bioconjugation

    NARCIS (Netherlands)

    Duvigneau, Joost; Schönherr, Holger; Vancso, Gyula J.

    2008-01-01

    In this paper, we report on the local thermal activation of thin polymer films for area-selective surface chemical modification on micrometer and nanometer length scales. The thermally induced activation of tert-butyl ester moieties in polystyrene-block-poly(tert-butyl acrylate) (PS-b-PtBA) block

  3. Preparation, Characterization and Thermal Degradation of Polyimide (4-APS/BTDA/SiO2 Composite Films

    Directory of Open Access Journals (Sweden)

    Arash Dehzangi

    2012-04-01

    Full Text Available Polyimide/SiO2 composite films were prepared from tetraethoxysilane (TEOS and poly(amic acid (PAA based on aromatic diamine (4-aminophenyl sulfone (4-APS and aromatic dianhydride (3,3,4,4-benzophenonetetracarboxylic dianhydride (BTDA via a sol-gel process in N-methyl-2-pyrrolidinone (NMP. The prepared polyimide/SiO2 composite films were characterized using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, scanning electron microscope (SEM and thermogravimetric analysis (TGA. The FTIR results confirmed the synthesis of polyimide (4-APS/BTDA and the formation of SiO2 particles in the polyimide matrix. Meanwhile, the SEM images showed that the SiO2 particles were well dispersed in the polyimide matrix. Thermal stability and kinetic parameters of the degradation processes for the prepared polyimide/SiO2 composite films were investigated using TGA in N2 atmosphere. The activation energy of the solid-state process was calculated using Flynn–Wall–Ozawa’s method without the knowledge of the reaction mechanism. The results indicated that thermal stability and the values of the calculated activation energies increased with the increase of the TEOS loading and the activation energy also varied with the percentage of weight loss for all compositions.

  4. Novel Programmable Shape Memory Polystyrene Film: A Thermally Induced Beam-power Splitter.

    Science.gov (United States)

    Li, Peng; Han, Yu; Wang, Wenxin; Liu, Yanju; Jin, Peng; Leng, Jinsong

    2017-03-09

    Micro/nanophotonic structures that are capable of optical wave-front shaping are implemented in optical waveguides and passive optical devices to alter the phase of the light propagating through them. The beam division directions and beam power distribution depend on the design of the micro/nanostructures. The ultimate potential of advanced micro/nanophotonic structures is limited by their structurally rigid, functional singleness and not tunable against external impact. Here, we propose a thermally induced optical beam-power splitter concept based on a shape memory polystyrene film with programmable micropatterns. The smooth film exhibits excellent transparency with a transmittance of 95% in the visible spectrum and optical stability during a continuous heating process up to 90 °C. By patterning double sided shape memory polystyrene film into erasable and switchable micro-groove gratings, the transmission light switches from one designed light divided directions and beam-power distribution to another because of the optical diffraction effect of the shape changing micro gratings during the whole thermal activated recovery process. The experimental and theoretical results demonstrate a proof-of-principle of the beam-power splitter. Our results can be adapted to further extend the applications of micro/nanophotonic devices and implement new features in the nanophotonics.

  5. Nanodiamond particles/PVDF nanocomposite flexible films: thermal, mechanical and physical properties

    Science.gov (United States)

    Jaleh, Babak; Sodagar, Shima; Momeni, Amir; Jabbari, Ameneh

    2016-08-01

    Recently, polymer nanocomposites reinforced with nanoparticles have attracted a lot of attention due to their unique physical and mechanical properties. In this work, poly (vinylidene fluoride)/nanodiamond particles nanocomposite films were prepared by solution casting method with various nanodiamond particles contents. The samples were investigated by Fourier transform infrared spectroscopy and x-ray diffraction technique. The results revealed an obvious α to β-phase transformation compared to pure PVDF. The most (or the maximum) phase transformation from α to β-phase (>90%) was found for nanocomposite film with 8% wt nanodiamond particles. Scanning electron micrographs showed considerable decrease in the size of spherulitic crystal structure of PVDF with adding nanoparticles. The photoluminescence property of nanocomposite films was investigated by photoluminescence spectroscopy and the optical band gap value was calculated from the UV-visible absorption spectra. The results showed that after the incorporation of nanoparticles into PVDF, the value of optical band gap decreased. Thermal stability of samples was studied by thermogravimetric analysis. Due to an increase in the electroactive phase (β) percentage by adding nanoparticles, the resistance of samples to thermal degradation improved. The mechanical properties of samples were investigated by tensile test and hardness measurements. The elastic modulus and hardness of samples were enhanced by adding nanodiamond particles and elongation to fracture decreased.

  6. 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.

  7. Effects of thermal annealing on elimination of deep defects in amorphous In–Ga–Zn–O thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Haochun; Ide, Keisuke [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Hiramatsu, Hidenori [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Materials Research Center for Element Strategy, Tokyo Institute of Technology, Mailbox SE-6, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Ueda, Shigenori [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Ohashi, Naoki [Materials Research Center for Element Strategy, Tokyo Institute of Technology, Mailbox SE-6, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Kumomi, Hideya [Materials Research Center for Element Strategy, Tokyo Institute of Technology, Mailbox SE-6, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Hosono, Hideo [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Materials Research Center for Element Strategy, Tokyo Institute of Technology, Mailbox SE-6, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Kamiya, Toshio, E-mail: tkamiya@msl.titech.ac.jp [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Materials Research Center for Element Strategy, Tokyo Institute of Technology, Mailbox SE-6, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)

    2016-09-01

    We investigated the effects of thermal annealing for high-density subgap states in amorphous In–Ga–Zn–O (a-IGZO) films by focusing on low-quality defective films deposited without O{sub 2} supply (LQ films). It was found that most of the subgap states were thermally unstable and decreased dramatically by annealing at ≤ 400 °C in O{sub 2}. These defects (but with different shapes) were further reduced by 600 °C annealing, whose subgap states appeared similar to that of a-IGZO films deposited at an optimum condition (high quality, HQ films) and annealed at 300 °C. However, electron Hall mobilities and field-effect mobilities of their thin-film transistors (TFTs) were low for the LQ films/TFTs even annealed at 600 °C compared to those for the HQ films/TFTs. It implies that not only the subgap states but also heavier structural disorder deteriorated the electron transport in the LQ films. The present results also suggest that although a-IGZO deposition without O{sub 2} supply is sometimes employed in particular for DC sputtering, supplying some O{sub 2} gas would be better to produce good TFTs at lower temperatures. - Highlights: • Effects of thermal annealing on subgap states in a-In–Ga–Zn–O films were studied. • Hard X-ray photoemission spectroscopy was employed. • Low-quality films require annealing at 600 °C to make an operating transistor. • This temperature is much higher than those for high-quality films (300–400 °C). • The high temperature is required because some subgap states are very stable.

  8. Effect of Molecular Weight on the Thermal and Spectroscopic Properties of Poly(vinyl alcohol) Films

    International Nuclear Information System (INIS)

    Khafagy, R.M.; Abd El-Kader, K.M.; Badr, Y.A.

    2009-01-01

    Thin films of Poly(vinyl alcohol) (PVA) with molecular weights 5000, 17000,72000 and 125000 g/mol were prepared by casting technique.Samples were thermally and spectroscopically investigated using TGA, DSC, FTIR and FT-Raman spectroscopy, in order to show how the thermal stability and structure of PVA might be correlated with its molecular weight. Thermal analysis showed that samples degrade in two steps mechanism. The mechanism observed for degradation in an inert atmosphere was in accordance with the accepted mechanism of elimination followed by pyrolisation. PVA 5000MW and PVA 17000Mw showed almost similar thermal behavior due to their expected similar structure. PVA 72000Mw showed lower thermal stability since it is characterized with the presence of the unstable C-O-C ether linkages, which lead to the fast melting of this sample. PVA 125000Mw showed the highest thermal stability because crosslinking of the main chains takes place due to introducing additional PVA units, which substitute each over oxygen atom. ΔH values obtained from DSC showed good accordance with TGA and Drtg analysis. Moreover, FTIR and FT-Raman results agreed well with thermal analysis, and confirmed our supposed structural changes which might take place as the molecular weight of the sample changes: since the water uptake, presence of ether linkages, and double bonds formulation due to crosslinking, were confirmed with FTIR and FT-Raman spectral analysis. The crystallinity percentage of the samples was calculated from Raman spectra and results confirmed our spectroscopic explanations. The thermal and spectroscopic behavior of the samples was explained as a result of the competitive action of at least three factors due to increasing the molecular weight: (i) diminution of the existing physical network due to changes in hydrogen bonding; (ii) formation of a chemical network; and (iii) introduction of flexible moieties due to the specific chemical structure after crosslinking

  9. Preparation of poly (arylene ether nitrile)/NzdFeB composite film with excellent thermal properties and tensile strength

    Science.gov (United States)

    Pan, Hai; Xu, Mingzhen; Liu, Xiaobo

    2017-12-01

    PEN/NdFeB composite films were prepared by the solution casting method. The thermal properties, fracture morphology and tensile strength of the composite films were tested by DSC, TGA, SEM and electromechanical universal testing machine, respectively. The results reveal that the composite film has good thermal properties and tensile strength. Glass-transition temperature and decomposition temperatures at weight loss of 5% ot the composite films retain at 166±1 C and 462±4 C, respectively. The composite film with 5 wt.% NdFeB has the best tensile strength value for 100.5 MPa. In addition, it was found that the NdFeB filler was well dispersed in PEN matrix by SEM analysis.

  10. Evaluating Origin of Electron Traps in Tris(8-hydroxyquinoline) Aluminum Thin Films using Thermally Stimulated Current Technique

    OpenAIRE

    Matsushima, Toshinori; Adachi, Chihaya

    2008-01-01

    We measured the energy distributions and concentrations of electron traps in O_2-unexposed and O_2-exposed tris(8-hydroxyquinoline) aluminum (Alq_3) films using a thermally stimulated current (TSC) technique to investigate how doping O_2 molecules in Alq_3 films affect the films' electron trap and electron transport characteristics. The results of our TSC studies revealed that Alq_3 films have an electron trap distribution with peak depths ranging from 0.075 to 0.1 eV and peak widths ranging ...

  11. Effects of high-temperature thermal annealing on the electronic properties of In-Ga-Zn oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qin; Song, Zhong Xiao; Ma, Fei, E-mail: mafei@mail.xjtu.edu.cn, E-mail: liyhemail@gmail.com; Li, Yan Huai, E-mail: mafei@mail.xjtu.edu.cn, E-mail: liyhemail@gmail.com [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Xu, Ke Wei [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an, Shaanxi 710049, China and Department of Physics and Opt-electronic Engineering, Xi' an University of Arts and Science, Xi' an, Shaanxi 710065 (China)

    2015-03-15

    Indium gallium zinc oxide (IGZO) thin films were deposited by radio-frequency magnetron sputtering at room-temperature. Then, thermal annealing was conducted to improve the structural ordering. X-ray diffraction and high-resolution transmission electron microscopy demonstrated that the as-deposited IGZO thin films were amorphous and crystallization occurred at 800 and 950 °C. As a result of crystallization at high temperature, the carrier concentration and the Hall mobility of IGZO thin films were sharply increased, which could be ascribed to the increased oxygen vacancies and improved structural ordering of the thin films.

  12. Fast Batch Production of High-Quality Graphene Films in a Sealed Thermal Molecular Movement System.

    Science.gov (United States)

    Xu, Jianbao; Hu, Junxiong; Li, Qi; Wang, Rubing; Li, Weiwei; Guo, Yufen; Zhu, Yongbo; Liu, Fengkui; Ullah, Zaka; Dong, Guocai; Zeng, Zhongming; Liu, Liwei

    2017-07-01

    Chemical vapor deposition (CVD) growth of high-quality graphene has emerged as the most promising technique in terms of its integrated manufacturing. However, there lacks a controllable growth method for producing high-quality and a large-quantity graphene films, simultaneously, at a fast growth rate, regardless of roll-to-roll (R2R) or batch-to-batch (B2B) methods. Here, a stationary-atmospheric-pressure CVD (SAPCVD) system based on thermal molecular movement, which enables fast B2B growth of continuous and uniform graphene films on tens of stacked Cu(111) foils, with a growth rate of 1.5 µm s -1 , is demonstrated. The monolayer graphene of batch production is found to nucleate from arrays of well-aligned domains, and the films possess few defects and exhibit high carrier mobility up to 6944 cm 2 V -1 s -1 at room temperature. The results indicate that the SAPCVD system combined with single-domain Cu(111) substrates makes it possible to realize fast batch-growth of high-quality graphene films, which opens up enormous opportunities to use this unique 2D material for industrial device applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 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)

  14. Effect of ZDDP concentration on the thermal film formation on steel, hydrogenated non-doped and Si-doped DLC

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, S. [Laboratory for Tribology and Interface Nanotechnology, University of Ljubljana, Ljubljana (Slovenia); Kovač, J. [Jozef Stefan Institute, Jamova 19, 1000 Ljubljana (Slovenia); Kalin, M., E-mail: mitjan.kalin@tint.fs.uni-lj.si [Laboratory for Tribology and Interface Nanotechnology, University of Ljubljana, Ljubljana (Slovenia)

    2016-10-15

    Highlights: • The effect of the ZDDP concentrations onto the steel, H-DLC and Si-DLC surfaces is investigated. • ZDDP film structure on the DLC coatings is different from steel. • Different concentrations of ZDDP do not affect the final chemical structure of the ZDDP film on any of the studied surfaces. • The thickness of the thermal film is linear with the concentration for a given surface. • The reactivity of the ZDDP film is higher on the steel surface than on the DLC coatings. - Abstract: This work focuses on the ZDDP concentration (1, 5 and 20 wt%) to form a ZDDP film on surfaces during static thermal tests at 150 °C. Silicon-doped and hydrogenated DLC coatings, as well as steel as reference, were studied using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The results show that, on the three surfaces, the structure of the ZDDP thermal film consists of identical groups of pyrophosphate and zinc oxide, while the sulphuric groups are dissimilar. On the steel surface, the sulphuric part consists of a mixture of organic sulphide and sulphohydryl groups, but on H-DLC and Si-DLC only organic sulphide groups are found; there are no sulphohydryl groups. Moreover, both ATR-FTIR and XPS show that different concentrations of ZDDP do not affect the final chemical structure of the ZDDP thermal film on any of the studied surfaces. In addition, the XPS results show that the thickness of the thermal film is linear with the concentration for the whole range from 1 to 20 wt%, supporting also its uniform chemical structure. These thicknesses further show that the reactivity of the ZDDP film is higher on the steel surface than on the DLC coatings.

  15. Magnetic and thermal properties of amorphous TbFeCo alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ke, E-mail: K.Wang@hqu.edu.cn; Dong, Shuo; Huang, Ya; Qiu, Yuzhen

    2017-07-15

    Highlights: • Significant increase in magnetization is observed in TbFeCo upon crystallization. • The crystallization temperature is determined in the range between 400 and 450 °C. • The activation barriers for structural changes are obtained successfully. • Better thermal stability against crystallization and oxidation is demonstrated in FeCo-rich sample than Tb-rich type. - Abstract: Amorphous TbFeCo material with perpendicular magnetic anisotropy is currently attracting more attention for potential applications in spintronic devices and logic memories. We systematically investigate magnetic, structural, thermal, optical and electrical properties of TbFeCo alloy films. It shows out-of-plane easy axis of the films turns into in-plane orientation after annealing. Significant increase in saturation magnetization in the temperature range between 400 and 450 °C is revealed by thermomagnetic measurements. The occurrence of crystallization and oxidation at high temperatures is confirmed by X-ray diffraction measurements. Pronounced changes in optical reflectance and sheet resistance are observed with temperature, in line with structural relaxation and change. The activation barriers for crystallization and oxidation are determined to be 1.01 eV and 0.83 eV, respectively, for FeCo-rich and Tb-rich samples. Better thermal stability against crystallization and oxidation is demonstrated in the FeCo-rich sample than the Tb-rich type. Our results provide some useful information for the alloy used in device fabrication.

  16. HR-EELS study of hydrogen bonding configuration, chemical and thermal stability of detonation nanodiamond films

    Energy Technology Data Exchange (ETDEWEB)

    Michaelson, Sh.; Akhvlediani, R. [Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Petit, T.; Girard, H.A.; Arnault, J.C. [CEA, LIST, Diamond Sensors Laboratory, F-91191 Gif sur Yvette (France); Hoffman, A., E-mail: choffman@tx.technion.ac.il [Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000 (Israel)

    2014-06-01

    Nano-diamond films composed of 3–10 nm grains prepared by the detonation method and deposited onto silicon substrates by drop-casting were examined by high resolution electron energy loss spectroscopy (HR-EELS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and secondary ion mass spectroscopy (SIMS). The impact of (i) ex-situ ambient annealing at 400 °C and (ii) ex-situ hydrogenation on hydrogen bonding and its thermal stability were examined. In order to clarify the changes in hydrogen bonding configuration detected on the different surfaces as a function of thermal annealing, in-situ hydrogenation by thermally activated atomic hydrogen was performed and examined. This study provides direct evidence that the exposure to ambient conditions and medium temperature ambient annealing have a pronounced effect on the hydrogen-carbon bonding configuration onto the nano-diamond surfaces. In-situ 1000 °C annealing results in irreversible changes of the film surface and partial nano-diamond silicidation.

  17. 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.

  18. Application of rapid thermal processing on SiNx thin film to solar cells

    Institute of Scientific and Technical Information of China (English)

    Youjie LI; Peiqing LUO; Zhibin ZHOU; Rongqiang CUI; Jianhua HUANG; Jingxiao WANG

    2008-01-01

    Rapid thermal processing (RTP) of SiNx thin films from PECVD with low temperature was investigated. A special processing condition of this technique which could greatly increase the minority lifetime was found in the experiments. The processing mechanism and the application of the technique to silicon solar cells fabrication were dis-cussed. A main achievement is an increase of the minority lifetime in silicon wafer with SiNx thin film by about 200% after the RTP was reached. PC-1D simulation results exhibit an enhancement of the efficiency of the solar cell by 0.42% coming from the minority lifetime improvement. The same experiment was also conducted with P-diffusion silicon wafers, but the increment of minority lifetime is just about 55%. It could be expected to improve the solar cell efficiency if it would be used in silicon solar cells fabrication with the combination of laser firing contact technique.

  19. Synthesis of nanocrystalline ceria thin films by low-temperature thermal decomposition of Ce-propionate

    International Nuclear Information System (INIS)

    Roura, P.; Farjas, J.; Ricart, S.; Aklalouch, M.; Guzman, R.; Arbiol, J.; Puig, T.; Calleja, A.; Peña-Rodríguez, O.; Garriga, M.; Obradors, X.

    2012-01-01

    Thin films of Ce-propionate (thickness below 20 nm) have been deposited by spin coating and pyrolysed into ceria at temperatures below 200 °C. After 1 h of thermal treatment, no signature of the vibrational modes of Ce-propionate is detected by infrared spectroscopy, indicating that decomposition has been completed. The resulting ceria films are nanocrystalline as revealed by X-ray diffraction (average grain size of 2–2.5 nm) and confirmed by microscopy. They are transparent in the visible region and show the characteristic band gap absorption below 400 nm. A direct band gap energy of 3.50 ± 0.05 eV has been deduced irrespective of the pyrolysis temperature (160, 180 and 200 °C).

  20. 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.

  1. 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.

  2. Morphology and thermal properties of PLA films plasticized with aliphatic oligoesters; Morfologia e propriedades termicas de filmes de PLA plastificados com oligoesteres alifaticos

    Energy Technology Data Exchange (ETDEWEB)

    Inacio, Erika M.; Dias, Marcos L., E-mail: erika.minacio@ima.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Lima, Maria Celiana P. [Instituto Federal do Rio de Janeiro (IFRJ), Duque de Caxias, RJ (Brazil)

    2015-07-01

    The addition of plasticizers to poly(lactic acid) (PLA) is one of the known ways of changing its ductility, making possible the modification of its mechanical and thermal properties. In this work, it was synthesized two biodegradable aliphatic oligoesters: oligo(trimethylene sebacate) (OST) and oligo(trimethylene malonate) (OMT), and these oligomers were used as plasticizer in cast films of commercial film grade PLA at concentrations of 1, 5 and 10 wt% of each plasticizer. X-ray diffraction (XRD) was used to investigate the morphology and differential scanning calorimetry (DSC) was also used aiming the evaluation of the thermal properties of these films. The PLA films containing no plasticizer showed an amorphous behavior, and the addition of PMT on the PLA films acted, simultaneously, decreasing the Tg, and rising the material's crystallinity. In contrast, the increased addition of OST to the PLA films did not change the Tg, and equally, did not have a significant changes in the material's crystallinity. Therefore, it was possible to observe the effect of the concentration of oligomers on the crystallinity of the films as well as the no plasticizer effect of the OST. (author)

  3. Morphology and thermal properties of PLA films plasticised with aliphatic oligoesters; Morfologia e propriedades termicas de filmes de PLA plastificados com oligoesteres alifaticos

    Energy Technology Data Exchange (ETDEWEB)

    Inacio, Erika M.; Dias, Marcos L., E-mail: erika.minacio@ima.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil); Lima, Maria Celiana P. [Instituto Federal do Rio de Janeiro (IFRJ), Duque de Caxias, RJ (Brazil)

    2013-07-01

    The addition of plasticizers to poly(lactic acid) (PLA) is one of the known ways of changing its ductility, making possible the modification of its mechanical and thermal properties. In this work, it was synthesized two biodegradable aliphatic oligoesters: oligo(trimethylene sebacate) (OST) and oligo(trimethylene malonate) (OMT), and these oligomers were used as plasticizer in cast films of commercial film grade PLA at concentrations of 1, 5 and 10 wt% of each plasticizer. X-ray diffraction (XRD) was used to investigate the morphology and differential scanning calorimetry (DSC) was also used aiming the evaluation of the thermal properties of these films. The PLA films containing no plasticizer showed an amorphous behavior, and the addition of PMT on the PLA films acted, simultaneously, decreasing the Tg, and rising the material's crystallinity. In contrast, the increased addition of OST to the PLA films did not change the Tg, and equally, did not have a significant changes in the material's crystallinity. Therefore, it was possible to observe the effect of the concentration of oligomers on the crystallinity of the films as well as the no plasticizer effect of the OST. (author)

  4. Effect of thermal annealing on the structural and optical properties of tris-(8-hydroxyquinoline)aluminum(III) (Alq3 ) films.

    Science.gov (United States)

    Cuba, M; Muralidharan, G

    2015-05-01

    Tris-(8-hydroxyquionoline)aluminum (Alq3 ) was synthesized and coated on to a glass substrate using the dip coating method. The structural and optical properties of the Alq3 film after thermal annealing from 50°C to 300°C in 50° steps was studied. The films have been prepared with 2 to 16 layers (42-324 nm). The thickness and thermal annealing of Alq3 films were optimized for maximum luminescence yield. The Fourier transform infrared spectrum confirms the formation of quinoline with absorption in the region 700 - 500/cm. Partial sublimation and decomposition of quinoline ion was observed with the Alq3 films annealed at 300°C. The X-ray diffraction pattern of the Alq3 film annealed at 50°C to 150°C reveals the amorphous nature of the films. The Alq3 film annealed above 150°C were crystalline nature. Film annealed at 150°C exhibits a photoluminescence intensity maximum at 512 nm when excited at 390 nm. The Alq3 thin film deposited with 10 layers (220 nm) at 150°C exhibited maximum luminescence yield. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Confinement of solar thermal energy by Nesa film; Nesa maku ni yoru taiyo netsu energy no fujikome

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, A; Yano, K; Kasuga, M; Daigo, Y [Yamanashi University, Yamanashi (Japan). Faculty of Engineering

    1997-11-25

    This paper reports a Nesa (SnO2) film as selective transmissive film for effective confinement of solar thermal energy. Solar light spectrum ranges from 0.3 to 2.0{mu}m, while thermal radiation from bodies at 100-200degC is infrared ray more than 2{mu}m. Consequently, a solar water heater using the film which can pass rays below 2.0{mu}m while reflect rays over 2.0{mu}m for windows is very efficient. The Nesa film reflects rays with wavelengths more than plasma wavelengths (controllable from 1 to several {mu}m) by plasma action of free electrons. The Nesa films with different carrier densities were fabricated by spraying deposition method at dopant rates (Sb/Sn) from 0 to 2mol%. The solar water heaters were prepared using normal glass and specific glass coated with the Nesa film as selective transmissive film. The heater using the glass coated with the Nesa film of 2{mu}m plasma wavelength for windows could efficiently confine solar heat. The Nesa film of 700nm plasma wavelength which can pass visible light while reflect infrared ray was effective to reduce cooling/heating losses. 3 refs., 6 figs.

  6. Improvement of Sol-Gel Derived PbZrxTi1-xO3 Film Properties Using Thermal Press Treatment

    Science.gov (United States)

    Kaneda, Toshihiko; Kim, Joo-Nam; Tokumitsu, Eisuke; Shimoda, Tatsuya

    2010-09-01

    A thermal press treatment was introduced in the sol-gel process of PbZrxTi1-xO3 (PZT) thin films for the first time and the crystalline and electrical characteristics of the PZT films were investigated. The thermal press treatment was applied to the amorphous PZT gel film before crystallization annealing. It is found that the crystalline orientation and grain size of the PZT film fabricated with the thermal press treatment are different from those of the film fabricated by the conventional sol-gel process without the thermal press treatment, even though the crystallization conditions are exactly the same. It is demonstrated that the electrical properties, especially leakage current density and breakdown field, are significantly improved for the PZT film fabricated with the thermal press treatment. Furthermore, we also demonstrate that the fatigue property is improved by introducing the thermal press treatment.

  7. Thermally stimulated currents in polycrystalline diamond films and their application to ultraviolet dosimetry

    International Nuclear Information System (INIS)

    Trajkov, E.; Prawer, S.

    1999-01-01

    Quantifying individual exposure to solar ultraviolet radiation (UVR) is imperative to understanding the epidemiology of UVR related skin cancer. The development of personal UVR dosimeters is hence essential for obtaining data regarding individual UVR exposure, which can then be used to establish appropriate protective measures for occupational and recreational exposure. Because diamond is a tissue equivalent material and has a wide band-gap, CVD polycrystalline diamond has been proposed for use in solar-blind UV dosimetry. It has been reported that the photoconductivity in polycrystalline diamond films is enhanced after UV illumination Photo-generated carriers can be trapped at some deep levels after illumination. Because these levels are deep the thermal release of carriers is a slow process at room temperature. Therefore the new carrier distribution reached after illumination can result in a metastable state because the temperature is too low to restore the initial equilibrium. The sample can be bought back to initial equilibrium by heating. If the current is recorded during heating of the samples one can observe current peaks corresponding to the thermal release of trapped carriers, the so-called thermally stimulated currents (TSC). From first-order kinetics, we find that the TSC intensity is proportional to the initial density of trapped carriers, n to . Since n to varies with the radiation dose, the measurement of TSC can find an application in radiation dosimetry since the measurement of TSC gives a direct measure of that dose. Nitrogen can be used to introduce deep traps in diamond. This investigation will involve examining the affect of the nitrogen concentration on the irradiation response of the films. Furthermore, we will analyse the fading rate of the TSC signal. If diamond films are to have a practical application in UVR dosimetry, then ideally we require a linear relationship between the dose response and the TSC, and we also require a low fading rate

  8. Thin copper oxide films prepared by ion beam sputtering with subsequent thermal oxidation: Application in chemiresistors

    Energy Technology Data Exchange (ETDEWEB)

    Horak, P., E-mail: phorak@ujf.cas.cz [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Řež (Czech Republic); Bejsovec, V.; Vacik, J.; Lavrentiev, V. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Řež (Czech Republic); Vrnata, M. [Department of Physics and Measurements, The University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6 (Czech Republic); Kormunda, M. [Department of Physics, Jan Evangelista Purkyně University in Ústí nad Labem, České mládeže 8, 400 96 Ústí nad Labem (Czech Republic); Danis, S. [Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic)

    2016-12-15

    Highlights: • A rapid oxidation process of thin copper films. • Sheet resistance up to 10{sup 9} Ω/◊. • Mixed oxide phase at 200 °C with significant hydroxide presence. • Gas sensing response to 1000 ppm of hydrogen and methanol vapours. • Increased sensitivity with Pd and Au catalyst to hydrogen and methanol, respectively. - Abstract: Copper oxide films were prepared by thermal oxidation of thin Cu films deposited on substrates by ion beam sputtering. The subsequent oxidation was achieved in the temperature range of 200 °C–600 °C with time of treatment from 1 to 7 h (with a 1-h step) in a furnace open to air. At temperatures 250 °C–600 °C, the dominant phase formed was CuO, while at 200 °C mainly the Cu{sub 2}O phase was identified. However, the oxidation at 200 °C led to a more complicated composition − in the depth Cu{sub 2}O phase was observed, though in the near-surface layer the CuO dominant phase was found with a significant presence of Cu(OH){sub 2}. A limited amount of Cu{sub 2}O was also found in samples annealed at 600 °C. The sheet resistance R{sub S} of the as-deposited Cu sample was 2.22 Ω/□, after gradual annealing R{sub S} was measured in the range 2.64 MΩ/□–2.45 GΩ/□. The highest R{sub S} values were obtained after annealing at 300 °C and 350 °C, respectively. Oxygen depth distribution was studied using the {sup 16}O(α,α) nuclear reaction with the resonance at energy 3032 keV. It was confirmed that the higher oxidation degree of copper is located in the near-surface region. Preliminary tests of the copper oxide films as an active layer of a chemiresistor were also performed. Hydrogen and methanol vapours, with a concentration of 1000 ppm, were detected by the sensor at an operating temperature of 300 °C and 350 °C, respectively. The response of the sensors, pointed at the p-type conductivity, was improved by the addition of thin Pd or Au catalytic films to the oxidic film surface. Pd-covered films showed

  9. Thermal Vapor Deposition and Characterization of Polymer-Ceramic Nanoparticle Thin Films and Capacitors

    Science.gov (United States)

    Iwagoshi, Joel A.

    Research on alternative energies has become an area of increased interest due to economic and environmental concerns. Green energy sources, such as ocean, wind, and solar power, are subject to predictable and unpredictable generation intermittencies which cause instability in the electrical grid. This problem could be solved through the use of short term energy storage devices. Capacitors made from composite polymer:nanoparticle thin films have been shown to be an economically viable option. Through thermal vapor deposition, we fabricated dielectric thin films composed of the polymer polyvinylidine fluoride (PVDF) and the ceramic nanoparticle titanium dioxide (TiO2). Fully understanding the deposition process required an investigation of electrode and dielectric film deposition. Film composition can be controlled by the mass ratio of PVDF:TiO2 prior to deposition. An analysis of the relationship between the ratio of PVDF:TiO2 before and after deposition will improve our understanding of this novel deposition method. X-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy were used to analyze film atomic concentrations. The results indicate a broad distribution of deposited TiO2 concentrations with the highest deposited amount at an initial mass concentration of 17% TiO2. The nanoparticle dispersion throughout the film is analyzed through atomic force microscopy and energy dispersive x-ray spectroscopy. Images from these two techniques confirm uniform TiO2 dispersion with cluster size less than 300 nm. These results, combined with spectroscopic analysis, verify control over the deposition process. Capacitors were fabricated using gold parallel plates with PVDF:TiO 2 dielectrics. These capacitors were analyzed using the atomic force microscope and a capacohmeter. Atomic force microscope images confirm that our gold films are acceptably smooth. Preliminary capacohmeter measurements indicate capacitance values of 6 nF and break down voltages of 2.4 V

  10. Robust design and thermal fatigue life prediction of anisotropic conductive film flip chip package

    International Nuclear Information System (INIS)

    Nam, Hyun Wook

    2004-01-01

    The use of flip-chip technology has many advantages over other approaches for high-density electronic packaging. ACF(Anisotropic Conductive Film) is one of the major flip-chip technologies, which has short chip-to-chip interconnection length, high productivity, and miniaturization of package. In this study, thermal fatigue life of ACF bonding flip-chip package has been predicted. Elastic and thermal properties of ACF were measured by using DMA and TMA. Temperature dependent nonlinear bi-thermal analysis was conducted and the result was compared with Moire interferometer experiment. Calculated displacement field was well matched with experimental result. Thermal fatigue analysis was also conducted. The maximum shear strain occurs at the outmost located bump. Shear stress-strain curve was obtained to calculate fatigue life. Fatigue model for electronic adhesives was used to predict thermal fatigue life of ACF bonding flip-chip packaging. DOE (Design Of Experiment) technique was used to find important design factors. The results show that PCB CTE (Coefficient of Thermal Expansion) and elastic modulus of ACF material are important material parameters. And as important design parameters, chip width, bump pitch and bump width were chose. 2 nd DOE was conducted to obtain RSM equation for the choose 3 design parameter. The coefficient of determination (R 2 ) for the calculated RSM equation is 0.99934. Optimum design is conducted using the RSM equation. MMFD (Modified Method for Feasible Direction) algorithm is used to optimum design. The optimum value for chip width, bump pitch and bump width were 7.87mm, 430μm, and 78μm, respectively. Approximately, 1400 cycles have been expected under optimum conditions. Reliability analysis was conducted to find out guideline for control range of design parameter. Sigma value was calculated with changing standard deviation of design variable. To acquire 6 sigma level thermal fatigue reliability, the Std. Deviation of design parameter

  11. Impact of an angiotensin analogue in treating thermal and combined radiation injuries

    Science.gov (United States)

    Jadhav, Sachin Suresh

    Background: In recent years there has been a growing concern regarding the use of nuclear weapons by terrorists. Such incidents in the past have shown that radiation exposure is often accompanied by other forms of trauma such as burns, wounds or infection; leading to increased mortality rates among the affected individuals. This increased risk with combined radiation injury has been attributed to the delayed wound healing observed in this injury. The Renin-Angiotensin System (RAS) has emerged as a critical regulator of wound healing. Angiotensin II (A-II) and Angiotensin (1-7) [A(1-7)] have been shown to accelerate the rate of wound healing in different animal models of cutaneous injury. Nor-Leu3-Angiotensin (1-7) [Nor-Leu3-A (1-7)], an analogue of A(1-7), is more efficient than both A-II and A(1-7) in its ability to improve wound healing and is currently in phase III clinical trials for the treatment of diabetic foot ulcers. Aims: The three main goals of this study were to; 1) Develop a combined radiation and burn injury (CRBI) model and a radiation-induced cutaneous injury model to study the pathophysiological effects of these injuries on dermal wound healing; 2) To treat thermal and CRBI injuries using Nor-Leu 3-A (1-7) and decipher the mechanism of action of this peptide and 3) Develop an in-vitro model of CRBI using dermal cells in order to study the effect of CRBI on individual cell types involved in wound healing. Results: CRBI results in delayed and exacerbated apoptosis, necrosis and inflammation in injured skin as compared to thermal injury by itself. Radiation-induced cutaneous injury shows a radiation-dose dependent increase in inflammation as well as a chronic inflammatory response in the higher radiation exposure groups. Nor-Leu3-A (1-7) can mitigate thermal and CRBI injuries by reducing inflammation, oxidative stress and DNA damage while increasing the rate of proliferation of dermal stem cells and re-epithelialization of injured skin. The in

  12. Thermal behaviour properties and corrosion resistance of organoclay/polyurethane film

    Science.gov (United States)

    Kurniawan, O.; Soegijono, B.

    2018-03-01

    Organoclay/polyurethane film composite was prepared by adding organoclay with different content (1, 3, and 5 wt.%) in polyurethane as a matrix. TGA and DSC showed decomposition temperature shifted to a lower point as organoclay content change. FT-IR spectra showed chemical bonding of organoclay and polyurethane as a matrix, which means that the bonding between filler and matrix occured and the composite was stronger but less bonding occur in composite with 5 wt.% organoclay. The corrosion resistance overall increased with the increasing organoclay content. Composite with 5 wt.% organoclay had more thermal stability and corrosion resistance may probably due to exfoliation of organoclay.

  13. Nanoscale mechanical and tribological properties of fluorocarbon films grafted onto plasma-treated low-density polyethylene surfaces

    International Nuclear Information System (INIS)

    Cheng, Q; Komvopoulos, K

    2012-01-01

    Fluorocarbon (FC) films were grafted onto Ar plasma-treated low-density polyethylene (LDPE) surfaces by plasma polymerization and deposition. The evolution of the surface morphology of the grafted FC films was investigated at different scales with an atomic force microscope. Nanoscale sliding experiments performed with a surface force microscope provided insight into the nanotribological properties of Ar plasma-treated LDPE, with and without grafted FC films, in terms of applied normal load and number of sliding cycles. The observed trends are explained in the context of microstructure models accounting for morphological and structure changes at the LDPE surface due to the effects of plasma treatment (e.g., selective etching of amorphous phase, chain crosslinking and FC film grafting) and surface sliding (e.g., crystalline lamellae alignment along the sliding direction). Nanoindentation experiments elucidated the effect of plasma treatment on surface viscoelasticity and global contact stiffness. The results of this study demonstrate that plasma-assisted grafting of FC films is an effective surface modification method for tuning the nanomechanical/tribological properties of polymers. (paper)

  14. Thermal and infrared-diode laser effects on indocyanine-green-treated corneal collagen

    Science.gov (United States)

    Timberlake, George T.; Patmore, Ann; Shallal, Assaad; McHugh, Dominic; Marshall, John

    1993-07-01

    It has been suggested that laser welds of collagenous tissues form by interdigitation and chemical bonding of thermally 'unraveled' collagen fibrils. We investigated this proposal by attempting to weld highly collagenous, avascular corneal tissue with an infrared (IR) diode laser as follows. First, the temperature at which corneal collagen shrinks and collagen fibrils 'split' into subfibrillary components was determined. Second, since use of a near-IR laser wavelength necessitated addition of an absorbing dye (indocyanine green (ICG) to the cornea, we measured absorption spectra of ICG-treated tissue to ensure that peak ICG absorbance did not change markedly when ICG was present in the cornea. Third, using gel electrophoresis of thermally altered corneal collagen, we searched for covalently crosslinked compounds predicted by the proposed welding mechanism. Finally, we attempted to weld partial thickness corneal incisions infused with ICG. Principal experimental findings were as follows: (1) Human corneal (type I) collagen splits into subfibrillary components at approximately 63 degree(s)C, the same temperature that produces collagen shrinkage. (2) Peak ICG absorption does not change significantly in corneal stroma or with laser heating. (3) No evidence was found for the formation of novel compounds or the loss of proteins as a result of tissue heating. All tissue treated with ICG, however, exhibited a novel 244 kD protein band indicating chemical activity between collagen and corneal stromal components. (4) Laser welding corneal incisions was unsuccessful possibly due to shrinkage of the sides of the incision, lack of incision compression during heating, or a less than optimal combination of ICG concentration and radiant exposure. In summary, these experiments demonstrate the biochemical and morphological complexity of ICG-enhanced IR laser-tissue welding and the need for further investigation of laser welding mechanisms.

  15. Thermal conductivity of ultra-thin chemical vapor deposited hexagonal boron nitride films

    International Nuclear Information System (INIS)

    Alam, M. T.; Haque, M. A.; Bresnehan, M. S.; Robinson, J. A.

    2014-01-01

    Thermal conductivity of freestanding 10 nm and 20 nm thick chemical vapor deposited hexagonal boron nitride films was measured using both steady state and transient techniques. The measured value for both thicknesses, about 100 ± 10 W m −1 K −1 , is lower than the bulk basal plane value (390 W m −1 K −1 ) due to the imperfections in the specimen microstructure. Impressively, this value is still 100 times higher than conventional dielectrics. Considering scalability and ease of integration, hexagonal boron nitride grown over large area is an excellent candidate for thermal management in two dimensional materials-based nanoelectronics

  16. Effectiveness of thermal annular procedures in treating discogenic low back pain.

    Science.gov (United States)

    Helm Ii, Standiford; Deer, Timothy R; Manchikanti, Laxmaiah; Datta, Sukdeb; Chopra, Pradeep; Singh, Vijay; Hirsch, Joshua A

    2012-01-01

    Persistent low back pain refractory to conservative treatment is a common problem that leads to widespread impairment, resulting in significant costs to society. The intervertebral disc is a major source of persistent low back pain. Technologies developed to treat this problem, including various surgical instrumentation and fusion techniques, have not reliably provided satisfactory results in terms of either pain relief or increased function. Thermal annular procedures (TAPs) were first developed in the late 1990s in an attempt to treat discogenic pain. The hope was that they would provide greater value than fusion in terms of efficacy, morbidity, and cost. Three technologies have been developed to apply heat to the annulus: intradiscal electrothermal therapy (IDET), discTRODE, and biacuplasty. Since nerve ingrowth and tissue regeneration in the annulus is felt to be the source of pain in discogenic low back pain, when describing the 3 above techniques we use the term "thermal annular procedures" rather than "thermal intradiscal procedures." We have specifically excluded studies treating the nucleus. TAPs have been the subject of significant controversy. Multiple reviews have been conducted resulting in varying conclusions. A systematic review of TAPs for the treatment of discogenic low back pain. To evaluate the effectiveness of TAPs in treating discogenic low back pain and to assess complications associated with those procedures. The available literature on TAPs in treating discogenic low back pain was reviewed. The quality assessment and clinical relevance criteria utilized were the Cochrane Musculoskeletal Review Group criteria for interventional techniques for randomized trials, and the criteria developed by the Newcastle-Ottawa Scale criteria for observational studies. The level of evidence was classified as good, fair, or poor based on the quality of evidence developed by the U.S. Preventive Services Task Force. Data sources included relevant literature

  17. Chemical states and optical properties of thermally evaporated Ge-Te and Ge-Sb-Te amorphous thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S.; Singh, D.; Shandhu, S. [Semiconductor Laboratory, Department of Physics, Guru Nanak Dev University Amritsar (India); Thangaraj, R., E-mail: rthangaraj@rediffmail.com [Semiconductor Laboratory, Department of Physics, Guru Nanak Dev University Amritsar (India)

    2012-07-15

    Thin amorphous films of Ge{sub 22}Sb{sub 22}Te{sub 56} and Ge{sub 50}Te{sub 50} have been prepared from their respective polycrystalline bulk on glass substrates by thermal evaporation technique. The amorphous nature of the films was checked with X-ray diffraction studies. Amorphous-to-crystalline transition of the films has been induced by thermal annealing and the structural phases have been identified by X-ray diffraction. The phase transformation temperature of the films was evaluated by temperature dependent sheet resistance measurement. The chemical structure of the amorphous films has been investigated using X-ray photoelectron spectroscopy and the role of Sb in phase change Ge{sub 22}Sb{sub 22}Te{sub 56} film is discussed. Survey and core level (Ge 3d, Te 3d, Te 4d, Sb 3p, Sb 3d, O 1s, C 1s) band spectra has been recorded and analyzed. For optical studies, the transmittance and the reflectance spectra were measured over the wavelength ranges 400-2500 nm using UV-vis-NIR spectroscopy. The optical band gap, refractive index and extinction coefficient are also presented for thermally evaporated amorphous thin films.

  18. 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.

  19. Comparison of the behavior of fibroblast and bone marrow-derived mesenchymal stem cell on nitrogen plasma-treated gelatin films

    International Nuclear Information System (INIS)

    Prasertsung, I.; Kanokpanont, S.; Mongkolnavin, R.; Wong, C.S.; Panpranot, J.; Damrongsakkul, S.

    2013-01-01

    The attachment and growth behavior of mouse fibroblast (L929) and rat bone marrow-derived mesenchymal stem cell (MSC) on nitrogen plasma-treated and untreated gelatin films was investigated and compared. The gelatin films were prepared by solution casting (0.05% w/v) and crosslinked using dehydrothermal treatment. The crosslinked gelatin films were treated with nitrogen alternating current (AC) 50 Hz plasma systems at various treatment time. The results on the attachment and growth of two cells; L929 and MSC, on plasma-treated gelatin film showed that the number of attached and proliferated cells on plasma-treated gelatin films was significantly increased compared to untreated samples. However, no significant difference between the number of attached L929 and MSC on plasma-treated gelatin was observed. The shorter population doubling time and higher growth rate of cells cultured on plasma-treated film indicated the greater growth of cells, compared to ones on untreated films. The greatest enhancement of cell attachment and growth were noticed when the film was treated with nitrogen plasma for 9 to 15 s. This suggested that the greater attachment and growth of both cells on gelatin films resulted from the change of surface properties, i.e. hydrophilicity, surface energy, and chemistry. The suitable water contact angle and oxygen/nitrogen ratio (O/N) of gelatin film for best L929 and MSC attachment were observed at 27–32° and 1.4, respectively. These conditions also provided the best proliferation of cells on plasma-treated gelatin films. - Highlights: • We compared the attachment and growth behavior of L929 and MSC. • The attachment of two cells on plasma-treated gelatin was significantly increased. • The shorter population doubling time and higher growth rate of cells were observed. • L929 fibroblast exhibited the greater proliferation, compared to MSC

  20. Achieving a Collapsible, Strong, and Highly Thermally Conductive Film Based on Oriented Functionalized Boron Nitride Nanosheets and Cellulose Nanofiber.

    Science.gov (United States)

    Wu, Kai; Fang, Jinchao; Ma, Jinrui; Huang, Rui; Chai, Songgang; Chen, Feng; Fu, Qiang

    2017-09-06

    Boron nitride nanosheet (BNNS) films receive wide attention in both academia and industry because of their high thermal conductivity (TC) and good electrical insulation capability. However, the brittleness and low strength of the BNNS film largely limit its application. Herein, functionalized BNNSs (f-BNNSs) with a well-maintained in-plane crystalline structure were first prepared utilizing urea in the aqueous solution via ball-milling for the purpose of improving their stability in water and enhancing the interaction with the polymer matrix. Then, a biodegradable and highly thermally conductive film with an orderly oriented structure based on cellulose nanofibers (CNFs) and f-BNNSs was prepared just by simple vacuum-assisted filtration. The modification of the BNNS and the introduction of the CNF result in a better orientation of the f-BNNS, sufficient connection between f-BNNS themselves, and strong interaction between f-BNNS and CNF, which not only make the prepared composite film strong and tough but also possess higher in-plane TC. An increase of 70% in-plane TC, 63.2% tensile strength, and 77.8% elongation could be achieved for CNF/f-BNNS films, compared with that for CNF/BNNS films at the filler content of 70%. Although at such a high f-BNNS content, this composite film can be bended and folded. It is even more interesting to find that the in-plane TC could be greatly enhanced with the decrease of the thickness of the film, and a value of 30.25 W/m K can be achieved at the thickness of ∼30 μm for the film containing 70 wt % f-BNNS. We believe that this highly thermally conductive film with good strength and toughness could have potential applications in next-generation highly powerful and collapsible electronic devices.

  1. Thin copper oxide films prepared by ion beam sputtering with subsequent thermal oxidation: Application in chemiresistors

    Science.gov (United States)

    Horak, P.; Bejsovec, V.; Vacik, J.; Lavrentiev, V.; Vrnata, M.; Kormunda, M.; Danis, S.

    2016-12-01

    Copper oxide films were prepared by thermal oxidation of thin Cu films deposited on substrates by ion beam sputtering. The subsequent oxidation was achieved in the temperature range of 200 °C-600 °C with time of treatment from 1 to 7 h (with a 1-h step) in a furnace open to air. At temperatures 250 °C-600 °C, the dominant phase formed was CuO, while at 200 °C mainly the Cu2O phase was identified. However, the oxidation at 200 °C led to a more complicated composition - in the depth Cu2O phase was observed, though in the near-surface layer the CuO dominant phase was found with a significant presence of Cu(OH)2. A limited amount of Cu2O was also found in samples annealed at 600 °C. The sheet resistance RS of the as-deposited Cu sample was 2.22 Ω/□, after gradual annealing RS was measured in the range 2.64 MΩ/□-2.45 GΩ/□. The highest RS values were obtained after annealing at 300 °C and 350 °C, respectively. Oxygen depth distribution was studied using the 16O(α,α) nuclear reaction with the resonance at energy 3032 keV. It was confirmed that the higher oxidation degree of copper is located in the near-surface region. Preliminary tests of the copper oxide films as an active layer of a chemiresistor were also performed. Hydrogen and methanol vapours, with a concentration of 1000 ppm, were detected by the sensor at an operating temperature of 300 °C and 350 °C, respectively. The response of the sensors, pointed at the p-type conductivity, was improved by the addition of thin Pd or Au catalytic films to the oxidic film surface. Pd-covered films showed an increased response to hydrogen at 300 °C, while Au-covered films were more sensitive to methanol vapours at 350 °C.

  2. Microstructural, nanomechanical, and microtribological properties of Pb thin films prepared by pulsed laser deposition and thermal evaporation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Broitman, Esteban, E-mail: esbro@ifm.liu.se [Thin Film Physics Division, IFM, Linköping University, SE-581 83 Linköping (Sweden); Flores-Ruiz, Francisco J. [Thin Film Physics Division, IFM, Linköping University, SE-581 83 Linköping, Sweden and Centro de Investigación y de Estudios Avanzados del I.P.N., Unidad Querétaro, Querétaro 76230 (Mexico); Di Giulio, Massimo [Università del Salento, Dipartimento di Matematica e Fisica “E. De Giorgi”, 73100 Lecce (Italy); Gontad, Francisco; Lorusso, Antonella; Perrone, Alessio [Università del Salento, Dipartimento di Matematica e Fisica “E. De Giorgi”, 73100 Lecce, Italy and INFN-Istituto Nazionale di Fisica Nucleare, 73100 Lecce (Italy)

    2016-03-15

    In this work, the authors compare the morphological, structural, nanomechanical, and microtribological properties of Pb films deposited by thermal evaporation (TE) and pulsed laser deposition (PLD) techniques onto Si (111) substrates. Films were investigated by scanning electron microscopy, surface probe microscopy, and x-ray diffraction in θ-2θ geometry to determine their morphology, root-mean-square (RMS) roughness, and microstructure, respectively. TE films showed a percolated morphology with densely packed fibrous grains while PLD films had a granular morphology with a columnar and tightly packed structure in accordance with the zone growth model of Thornton. Moreover, PLD films presented a more polycrystalline structure with respect to TE films, with RMS roughness of 14 and 10 nm, respectively. Hardness and elastic modulus vary from 2.1 to 0.8 GPa and from 14 to 10 GPa for PLD and TE films, respectively. A reciprocal friction test has shown that PLD films have lower friction coefficient and wear rate than TE films. Our study has demonstrated for first time that, at the microscale, Pb films do not show the same simple lubricious properties measured at the macroscale.

  3. Defects and morphological changes in nanothin Cu films on polycrystalline Mo analyzed by thermal helium desorption spectrometry

    International Nuclear Information System (INIS)

    Venugopal, V.; Seijbel, L.J.; Thijsse, B.J.

    2005-01-01

    Thermal helium desorption spectrometry (THDS) has been used for the investigation of defects and thermal stability of thin Cu films (5-200 A ) deposited on a polycrystalline Mo substrate in ultrahigh vacuum. These films are metastable at room temperature. On heating, the films transform into islands, giving rise to a relatively broad peak in the helium desorption spectra. The temperature of this island formation is dependent on film thickness, being 417 K for 10 A and 1100 K for a 200 A film. The activation energy for island formation was found to be 0.3±0.1 eV for 75 A film. Grain boundaries have a strong effect on island formation. The defect concentration in the as-deposited films is ∼5x10 -4 , for films thicker than 50 A and more for thinner films. Helium release from monovacancies was identified in the case of a 200 A film. Helium release was also seen during sublimation of the Cu film (∼1350 K). Overlayer experiments were used to identify helium trapped close to the film surface. An increase of the substrate temperature during deposition resulted in a film that had already formed islands. Argon-ion assistance (250 eV) during film deposition with an ion/atom ratio of ∼0.1 resulted in a significant enhancement of helium trapping in the films. The argon concentration in the films was found to be 10 -3 . The temperature of island formation was increased due to argon-ion assistance. The helium and argon desorption spectra are found to be similar, which is due to most of the helium becoming trapped in the defects created by the argon beam. The role of the Mo surface in affecting the defects at the film-substrate interface is investigated. The effect of variation of helium fluence and helium implantation energy is also considered. The present THDS results of Cu/poly-Mo are compared to those of Cu/Mo(100) and Cu/Mo(100) reported earlier

  4. Magnetic and thermal properties of amorphous TbFeCo alloy films

    Science.gov (United States)

    Wang, Ke; Dong, Shuo; Huang, Ya; Qiu, Yuzhen

    2017-07-01

    Amorphous TbFeCo material with perpendicular magnetic anisotropy is currently attracting more attention for potential applications in spintronic devices and logic memories. We systematically investigate magnetic, structural, thermal, optical and electrical properties of TbFeCo alloy films. It shows out-of-plane easy axis of the films turns into in-plane orientation after annealing. Significant increase in saturation magnetization in the temperature range between 400 and 450 °C is revealed by thermomagnetic measurements. The occurrence of crystallization and oxidation at high temperatures is confirmed by X-ray diffraction measurements. Pronounced changes in optical reflectance and sheet resistance are observed with temperature, in line with structural relaxation and change. The activation barriers for crystallization and oxidation are determined to be 1.01 eV and 0.83 eV, respectively, for FeCo-rich and Tb-rich samples. Better thermal stability against crystallization and oxidation is demonstrated in the FeCo-rich sample than the Tb-rich type. Our results provide some useful information for the alloy used in device fabrication.

  5. Evolution of lateral ordering in symmetric block copolymer thin films upon rapid thermal processing

    International Nuclear Information System (INIS)

    Ceresoli, Monica; Ferrarese Lupi, Federico; Seguini, Gabriele; Perego, Michele; Sparnacci, Katia; Gianotti, Valentina; Antonioli, Diego; Laus, Michele; Boarino, Luca

    2014-01-01

    This work reports experimental findings about the evolution of lateral ordering of lamellar microdomains in symmetric PS-b-PMMA thin films on featureless substrates. Phase separation and microdomain evolution are explored in a rather wide range of temperatures (190–340 °C) using a rapid thermal processing (RTP) system. The maximum processing temperature that enables the ordering of block copolymers without introducing any significant degradation of macromolecules is identified. The reported results clearly indicate that the range of accessible temperatures in the processing of these self-assembling materials is mainly limited by the thermal instability of the grafted random copolymer layer, which starts to degrade at T > 300 °C, inducing detachment of the block copolymer thin film. For T ⩽ 290 °C, clear dependence of correlation length (ξ) values on temperature is observed. The highest level of lateral order achievable in the current system in a quasi-equilibrium condition was obtained at the upper processing temperature limit after an annealing time as short as 60 s. (paper)

  6. Diketopyrrolopyrrole-based polymer:fullerene nanoparticle films with thermally stable morphology for organic photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, Natalie P. [Univ. of Newcastle, Callaghan NSW (Australia). Centre for Organic Electronics; Vaughan, Ben [Univ. of Newcastle, Callaghan NSW (Australia). Centre for Organic Electronics; CSIRO Energy Technology, Newcastle (Australia); Williams, Evan L. [Inst. of Materials Research and Engineering (IMRE), Agency for Science, Technology, and Research (A*STAR), Singapore (Singapore); Kroon, Renee [Univ. of South Australia, Mawson Lakes Campus, SA (Australia). Ian Wark Research Inst.; Chalmers Univ. of Technology, Goteborg (Sweden). Dept. of Chemical and Biological Engineering/Polymer Technology; Anderrson, Mats R. [Univ. of South Australia, Mawson Lakes Campus, SA (Australia). Ian Wark Research Inst.; Chalmers Univ. of Technology, Goteborg (Sweden). Dept. of Chemical and Biological Engineering/Polymer Technology; Kilcoyne, A. L. David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Sonar, Prashant [Inst. of Materials Research and Engineering (IMRE), Agency for Science, Technology, and Research (A*STAR), Singapore (Singapore); Queensland Univ. of Technology (QUT), Brisbane (Australia). School of Chemistry, Physics and Mechanical Engineering; Zhou, Xiaojing [Univ. of Newcastle, Callaghan NSW (Australia). Centre for Organic Electronics; Dastoor, Paul C. [Univ. of Newcastle, Callaghan NSW (Australia). Centre for Organic Electronics; Belcher, Warwick J. [Univ. of Newcastle, Callaghan NSW (Australia). Centre for Organic Electronics

    2017-02-02

    Polymer:fullerene nanoparticles (NPs) offer two key advantages over bulk heterojunction (BHJ) films for organic photovoltaics (OPVs), water-processability and potentially superior morphological control. Once an optimal active layer morphology is reached, maintaining this morphology at OPV operating temperatures is key to the lifetime of a device. Here in this paper we study the morphology of the PDPP-TNT (poly{3,6-dithiophene-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-naphthalene}):PC71BM ([6,6]-phenyl C71 butyric acid methyl ester) NP system and then compare the thermal stability of NP and BHJ films to the common poly(3-hexylthiophene) (P3HT): phenyl C61 butyric acid methyl ester (PC61BM) system. We find that material Tg plays a key role in the superior thermal stability of the PDPP-TNT:PC71BM system; whereas for the P3HT:PC61BM system, domain structure is critical.

  7. Effect of Single and Double Stage Chemically Treated Kenaf Fibers on Mechanical Properties of Polyvinyl Alcohol Film

    Directory of Open Access Journals (Sweden)

    Md Ershad Ali

    2014-12-01

    Full Text Available The physico-mechanical properties of lignocellulosic kenaf fiber reinforced polyvinyl alcohol (PVA biocomposite films were investigated. To improve the properties of the biocomposite, kenaf fibers were chemically treated separately in a single stage (with Cr2(SO4312(H2O and double stages (with CrSO4 and NaHCO3 to improve the adhesion and compatibility between the kenaf fiber and PVA matrix. PVA was reinforced with various compositions of chemically treated kenaf fiber by using a solution casting technique. Microstructural analyses and mechanical tests were subsequently conducted. Scanning electron microscopic analysis indicated that chemical treatment improved the uniformity distribution of kenaf fiber within the PVA matrix. FTIR and XRD analyses confirmed the presence of chromium on the fiber surface. The tensile strength of PVA reinforced with chemical treated kenaf fiber was found to be higher than those reinforced with untreated kenaf. The Young’s modulus, flexural strength, and flexural modulus increased with fiber loading for both untreated and treated kenaf fiber reinforced PVA films. The double stage treated kenaf fiber showed better mechanical properties and lower moisture uptake than the single stage treated kenaf fiber.

  8. Processing Conditions, Thermal and Mechanical Responses of Stretchable Poly (Lactic Acid)/Poly (Butylene Succinate) Films.

    Science.gov (United States)

    Fortunati, Elena; Puglia, Debora; Iannoni, Antonio; Terenzi, Andrea; Kenny, José Maria; Torre, Luigi

    2017-07-16

    Poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) based films containing two different plasticizers [Acetyl Tributyl Citrate (ATBC) and isosorbide diester (ISE)] at three different contents (15 wt %, 20 wt % and 30 wt %) were produced by extrusion method. Thermal, morphological, mechanical and wettability behavior of produced materials was investigated as a function of plasticizer content. Filmature parameters were also adjusted and optimized for different formulations, in order to obtain similar thickness for different systems. Differential scanning calorimeter (DSC) results and evaluation of solubility parameter confirmed that similar miscibility was obtained for ATBC and ISE in PLA, while the two selected plasticizers resulted as not efficient for plasticization of PBS, to the limit that the PBS-30ATBC resulted as not processable. On the basis of these results, isosorbide-based plasticizer was considered a suitable agent for modification of a selected blend (PLA/PBS 80:20) and two mixing approaches were used to identify the role of ISE in the plasticization process: results from mechanical analysis confirmed that both produced PLA-PBS blends (PLA85-ISE15)-PBS20 and (PLA80-PBS20)-ISE15 could guarantee advantages in terms of deformability, with respect to the PLA80-PBS20 reference film, suggesting that the promising use of these stretchable PLA-PBS based films plasticized with isosorbide can provide novel solutions for food packaging applications.

  9. Characterization of thermally evaporated lead iodide films aimed for the detection of X-rays

    International Nuclear Information System (INIS)

    Caldeira Filho, A.M.; Mulato, M.

    2011-01-01

    Some semiconductor materials such as lead iodide (PbI 2 ) have applications in the detection of ionizing radiation at room temperature using the direct detection method. In this work we investigate lead iodide films deposited by thermal evaporation. The morphology, structure, and electric properties were investigated as a function of deposition height, i.e. the distance between evaporation-boat and substrates. The results show a morphology of vertical leaves and X-ray diffraction shows just one preferential orientation along the direction 110. Energy dispersive spectroscopy reveals that the films are not stoichiometric, with excess iodine atoms. Electrical resistivity of about 10 8 Ω cm was measured. This is smaller than for the bulk due to structural defects. The values of activation energy for electric transport increase from 0.52 up to 1.1 eV with decreasing deposition height, what indicates that the best film is the one deposited at the shortest distance. Exposure under X-ray mammographic energy shows a linear behavior up to 500 mR. No variation in sensibility was observed between 22 and 30 kVp.

  10. Improved behavior of cooper-amine complexes during thermal annealing for conductive thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Ayag, Kevin Ray; Panama, Gustavo; Paul, Shrabani; Kim, Hong Doo [Dept. of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin (Korea, Republic of)

    2017-02-15

    Previous studies successfully produced conductive thin films from organo-metallic-compounds-based inks. Some inks like those made from copper salt and amines, however, tend to move during thermal annealing and, thus, affect the conductive pattern on the substrate. In this study, conductive inks were synthesized by forming complexes of copper with amines and/or blended amines. To build-up an organo-metallic framework and preserve the pattern throughout the annealing period, diamine was added to the complex in different proportions. The prepared inks were coated on glass substrate and were annealed on a hot plate at 170°C under the gaseous mixture of formic acid and alcohol for 5 min. The metallic film was observed to retain the original pattern of the ink during and after annealing. Adhesion on the substrate was also improved. Inks with blended amines produced films with lower resistivities. The lowest electrical resistivity recorded was 4.99 μΩ cm, three times that of bulk copper.

  11. Thermoelectric properties of V{sub 2}O{sub 5} thin films deposited by thermal evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, R.; Loureiro, J., E-mail: joa.loureiro@gmail.com; Nogueira, A.; Elangovan, E.; Pinto, J.V.; Veiga, J.P.; Busani, T.; Fortunato, E.; Martins, R.; Ferreira, I., E-mail: imf@fct.unl.pt

    2013-10-01

    This work reports the structural, optical, electrical and thermoelectric properties of vanadium pentoxide (V{sub 2}O{sub 5}) thin films deposited at room temperature by thermal evaporation on Corning glass substrates. A post-deposition thermal treatment up to 973 K under atmospheric conditions induces the crystallization of the as-deposited amorphous films with an orthorhombic V{sub 2}O{sub 5} phase with grain sizes around 26 nm. As the annealing temperature rises up to 773 K the electrical conductivity increases. The films exhibit thermoelectric properties with a maximum Seebeck coefficient of −218 μV/K and electrical conductivity of 5.5 (Ω m){sup −1}. All the films show NIR-Vis optical transmittance above 60% and optical band gap of 2.8 eV.

  12. Data of thermal degradation and dynamic mechanical properties of starch-glycerol based films with citric acid as crosslinking agent.

    Science.gov (United States)

    González Seligra, Paula; Medina Jaramillo, Carolina; Famá, Lucía; Goyanes, Silvia

    2016-06-01

    Interest in biodegradable edible films as packaging or coating has increased because their beneficial effects on foods. In particular, food products are highly dependents on thermal stability, integrity and transition process temperatures of the packaging. The present work describes a complete data of the thermal degradation and dynamic mechanical properties of starch-glycerol based films with citric acid (CA) as crosslinking agent described in the article titled: "Biodegradable and non-retrogradable eco-films based on starch-glycerol with citric acid as crosslinking agent" González Seligra et al. (2016) [1]. Data describes thermogravimetric and dynamical mechanical experiences and provides the figures of weight loss and loss tangent of the films as a function of the temperature.

  13. 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

  14. 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.

  15. Effect of filling surface-treated pyrolytic char on resistivity of rubber films

    Directory of Open Access Journals (Sweden)

    Pattraporn Yamkaya

    2015-03-01

    Full Text Available In this research, natural rubber (NR films filled with pyrolytic tire char, carbon black N234 and N330 were compared for their electrical resistivity. The filler loading was varied to be 5, 10, 15, 20 and 25% of dry rubber content. The effect of surfactant which is 2 %w/v sodium dodecyl sulfate (SDS was also investigated. In the experiments, it was necessary to disperse the pyrolytic char in ethyl alcohol while disperse carbon black (CB in ammonium hydroxide solution prior to mixing with the rubber latex and the filled NR film was prepared by casting the mixture on a plate. It was found that increasing the amount of pyrolytic char in the NR film could lower its resistivity. The surfactant, SDS, could help better dispersion of both CB and pyrolytic char, thereby decreasing the resistivity. In a separate experiment where hexane vapor was absorbed in NR film without surfactant, in the first 30 seconds, the rate of increasing resistivity of the CB-filled film was not seen as clearly as that of pyrolytic-char-filled film. For the films with surfactant, the slow increase in resistivity of the NR films filled with N330 and pyrolytic char during adsorbing hexane vapor was observed.

  16. 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.

  17. Annealing effect of thermal spike in MgO thin film prepared by cathodic vacuum arc deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Daoyun, E-mail: zhudy@gdut.edu.cn [Experiment Teaching Department, Guangdong University of Technology, Guangzhou 510006 (China); State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Zhao, Shoubai [School of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510400 (China); Zheng, Changxi; Chen, Dihu [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); He, Zhenhui, E-mail: stshzh@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

    2013-12-16

    MgO films were prepared by using pulsed cathodic vacuum arc deposition technique. The substrate bias voltage was in the range of −150 to −750 V. Film structure was investigated by X-ray diffraction (XRD). The annealing effect of thermal spike produced by the impacting of energetic ions was analyzed. The calculated results showed that the lifetime of a thermal spike generated by an energetic ion with the energy of 150 eV was less than one picosecond and it was sufficient to allow Mg{sup 2+} or O{sup 2-} to move one bond length to satisfy the intrinsic stress relief in the affected volume. The MgO(200) lattice spacings of the films deposited at different bias voltages were all larger than the ideal value of 2.1056 Å. As the bias amplitude increased the lattice spacing decreased, which indicated that the compressive stress in the film was partially relieved with increasing impacting ion energy. The stress relief also could be reflected from the film orientation with bias voltage. The biaxial elastic modulus for MgO(100), MgO(110) and MgO(111) planes were calculated and they were M{sub (100)} = 199 GPa, M{sub (110)} = 335 GPa and M{sub (111)} = 340 GPa, respectively. The M values indicated that the preferred orientation will be MgO(200) due to the minimum energy configuration when the lattice strain was large. It was confirmed by the XRD results in our experiments. - Highlights: • MgO thin films with preferred orientation were obtained by CVAD technique. • Annealing effect of a thermal spike in MgO film was discussed. • Lattice spacing of MgO film decreased with the increase of bias voltage. • Film preferred orientation changed from (200) to (220) as the bias voltage increased.

  18. Effect of ZDDP concentration on the thermal film formation on steel, hydrogenated non-doped and Si-doped DLC

    Science.gov (United States)

    Akbari, S.; Kovač, J.; Kalin, M.

    2016-10-01

    This work focuses on the ZDDP concentration (1, 5 and 20 wt%) to form a ZDDP film on surfaces during static thermal tests at 150 °C. Silicon-doped and hydrogenated DLC coatings, as well as steel as reference, were studied using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The results show that, on the three surfaces, the structure of the ZDDP thermal film consists of identical groups of pyrophosphate and zinc oxide, while the sulphuric groups are dissimilar. On the steel surface, the sulphuric part consists of a mixture of organic sulphide and sulphohydryl groups, but on H-DLC and Si-DLC only organic sulphide groups are found; there are no sulphohydryl groups. Moreover, both ATR-FTIR and XPS show that different concentrations of ZDDP do not affect the final chemical structure of the ZDDP thermal film on any of the studied surfaces. In addition, the XPS results show that the thickness of the thermal film is linear with the concentration for the whole range from 1 to 20 wt%, supporting also its uniform chemical structure. These thicknesses further show that the reactivity of the ZDDP film is higher on the steel surface than on the DLC coatings.

  19. Thermally-driven H interaction with HfO2 films deposited on Ge(100) and Si(100)

    Science.gov (United States)

    Soares, G. V.; Feijó, T. O.; Baumvol, I. J. R.; Aguzzoli, C.; Krug, C.; Radtke, C.

    2014-01-01

    In the present work, we investigated the thermally-driven H incorporation in HfO2 films deposited on Si and Ge substrates. Two regimes for deuterium (D) uptake were identified, attributed to D bonded near the HfO2/substrate interface region (at 300 °C) and through the whole HfO2 layer (400-600 °C). Films deposited on Si presented higher D amounts for all investigated temperatures, as well as, a higher resistance for D desorption. Moreover, HfO2 films underwent structural changes during annealings, influencing D incorporation. The semiconductor substrate plays a key role in this process.

  20. Superfluidity in two-dimensions. A thermal conductivity study of 4He and 3He- 4He mixture films

    International Nuclear Information System (INIS)

    Finotello, D.

    1992-01-01

    We review measurement of the thermal transport of 4 He films and 3 He- 4 He mixture films near the superfluid transition. These measurements were performed on helium films of thickness ranging from 12 to 156 A and mixture films with 3 He concentration up to 2%. The superfluid transition temperature for these films ranged from 1.2 to 2.2. K. We discuss universal features of the data as well as the behavior of the ratio of the vortex diffusion constant to vortex core-parameter, the sharpness of the transition and the superfluid transition temperature as a function of thickness and concentration. We also describe new experiments that will contribute to a better understanding of the observed behavior (Author)

  1. 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

  2. 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.

  3. Magneto-transport properties of oriented Mn{sub 2}CoAl films sputtered on thermally oxidized Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Xu, G. Z.; Du, Y.; Zhang, X. M.; Liu, E. K.; Wang, W. H., E-mail: wenhong.wang@iphy.ac.cn; Wu, G. H. [State Key Laboratory for Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, H. G. [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124 (China)

    2014-06-16

    Spin gapless semiconductors are interesting family of materials by embracing both magnetism and semiconducting due to their unique band structure. Its potential application in future spintronics requires realization in thin film form. In this Letter, we report fabrication and transport properties of spin gapless Mn{sub 2}CoAl films prepared on thermally oxidized Si substrates by magnetron sputtering deposition. The films deposited at 673 K are well oriented to (001) direction and display a uniform-crystalline surface. Magnetotransport measurements on the oriented films reveal a semiconducting-like resistivity, small anomalous Hall conductivity, and linear magnetoresistance representative of the transport signatures of spin gapless semiconductors. The magnetic properties of the films have also been investigated and compared to that of bulk Mn{sub 2}CoAl, showing small discrepancy induced by the composition deviation.

  4. 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.

  5. Preparation and modification of VO2 thin film on R-sapphire substrate by rapid thermal process

    Science.gov (United States)

    Zhu, Nai-Wei; Hu, Ming; Xia, Xiao-Xu; Wei, Xiao-Ying; Liang, Ji-Ran

    2014-04-01

    The VO2 thin film with high performance of metal-insulator transition (MIT) is prepared on R-sapphire substrate for the first time by magnetron sputtering with rapid thermal process (RTP). The electrical characteristic and THz transmittance of MIT in VO2 film are studied by four-point probe method and THz time domain spectrum (THz-TDS). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and search engine marketing (SEM) are employed to analyze the crystalline structure, valence state, surface morphology of the film. Results indicate that the properties of VO2 film which is oxidized from the metal vanadium film in oxygen atmosphere are improved with a follow-up RTP modification in nitrogen atmosphere. The crystallization and components of VO2 film are improved and the film becomes compact and uniform. A better phase transition performance is shown that the resistance changes nearly 3 orders of magnitude with a 2-°C hysteresis width and the THz transmittances are reduced by 64% and 60% in thermal and optical excitation respectively.

  6. 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.

  7. Variation of microstructural and optical properties in SILAR grown ZnO thin films by thermal treatment.

    Science.gov (United States)

    Valanarasu, S; Dhanasekaran, V; Chandramohan, R; Kulandaisamy, I; Sakthivelu, A; Mahalingam, T

    2013-08-01

    The influence of thermal treatment on the structural and morphological properties of the ZnO films deposited by double dip Successive ionic layer by adsorption reaction is presented. The effect of annealing temperature and time in air ambient is presented in detail. The deposited films were annealed from 200 to 400 degrees C in air and the structural properties were determined as a function of annealing temperature by XRD. The studies revealed that films were exhibiting preferential orientation along (002) plane. The other structural parameters like the crystallite size (D), micro strain (epsilon), dislocation density (delta) and stacking fault (alpha) of as-deposited and annealed ZnO films were evaluated and reported. The optical properties were also studied and the band gap of the ZnO thins films varied from 3.27 to 3.04 eV with the annealing temperature. SEM studies revealed that the hexagonal shaped grains with uniformly distributed morphology in annealed ZnO thin films. It has been envisaged using EDX analysis that the near stoichiometric composition of the film can be attained by thermal treatment during which microstructural changes do occur.

  8. 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.

  9. Preparation and modification of VO2 thin film on R-sapphire substrate by rapid thermal process

    International Nuclear Information System (INIS)

    Zhu Nai-Wei; Hu Ming; Xia Xiao-Xu; Wei Xiao-Ying; Liang Ji-Ran

    2014-01-01

    The VO 2 thin film with high performance of metal–insulator transition (MIT) is prepared on R-sapphire substrate for the first time by magnetron sputtering with rapid thermal process (RTP). The electrical characteristic and THz transmittance of MIT in VO 2 film are studied by four-point probe method and THz time domain spectrum (THz-TDS). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and search engine marketing (SEM) are employed to analyze the crystalline structure, valence state, surface morphology of the film. Results indicate that the properties of VO 2 film which is oxidized from the metal vanadium film in oxygen atmosphere are improved with a follow-up RTP modification in nitrogen atmosphere. The crystallization and components of VO 2 film are improved and the film becomes compact and uniform. A better phase transition performance is shown that the resistance changes nearly 3 orders of magnitude with a 2-°C hysteresis width and the THz transmittances are reduced by 64% and 60% in thermal and optical excitation respectively. (interdisciplinary physics and related areas of science and technology)

  10. Rapid thermal and swift heavy ion induced annealing of Co ion implanted GaN films

    International Nuclear Information System (INIS)

    Baranwal, V.; Pandey, A. C.; Gerlach, J. W.; Rauschenbach, B.; Karl, H.; Kanjilal, D.; Avasthi, D. K.

    2008-01-01

    Thin epitaxial GaN films grown on 6H-SiC(0001) substrates were implanted with 180 keV Co ions at three different fluences. As-implanted samples were characterized with secondary ion mass spectrometry and Rutherford backscattering spectrometry to obtain the Co depth profiles and the maximum Co concentrations. As-implanted samples were annealed applying two different techniques: rapid thermal annealing and annealing by swift heavy ion irradiation. Rapid thermal annealing was done at two temperatures: 1150 deg. C for 20 s and 700 deg. C for 5 min. 200 MeV Ag ions at two fluences were used for annealing by irradiation. Crystalline structure of the pristine, as-implanted, and annealed samples was investigated using x-ray diffraction, and the results were compared. Improvement of the crystalline quality was observed for rapid thermal annealed samples at the higher annealing temperature as confirmed with rocking curve measurements. The results indicate the presence of Co clusters in these annealed samples. Swift heavy ion irradiation with the parameters chosen for this study did not lead to a significant annealing

  11. 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.

  12. Multifunctional PLA-PHB/cellulose nanocrystal films: processing, structural and thermal properties.

    Science.gov (United States)

    Arrieta, M P; Fortunati, E; Dominici, F; Rayón, E; López, J; Kenny, J M

    2014-07-17

    Cellulose nanocrystals (CNCs) synthesized from microcrystalline cellulose by acid hydrolysis were added into poly(lactic acid)-poly(hydroxybutyrate) (PLA-PHB) blends to improve the final properties of the multifunctional systems. CNC were also modified with a surfactant (CNCs) to increase the interfacial adhesion in the systems maintaining the thermal stability. Firstly, masterbatch pellets were obtained for each formulation to improve the dispersion of the cellulose structures in the PLA-PHB and then nanocomposite films were processed. The thermal stability as well as the morphological and structural properties of nanocomposites was investigated. While PHB increased the PLA crystallinity due to its nucleation effect, well dispersed CNC and CNCs not only increased the crystallinity but also improved the processability, the thermal stability and the interaction between both polymers especially in the case of the modified CNCs based PLA-PHB formulation. Likewise, CNCs were better dispersed in PLA-CNCs and PLA-PHB-CNCs, than CNC. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Compositional changes in the channel layer of an amorphous In–Ga–Zn-O thin film transistor after thermal annealing

    International Nuclear Information System (INIS)

    Kang, Jiyeon; Lee, Su Jeong; Myoung, Jae-Min; Kim, Chul-Hong; Chae, Gee Sung; Jun, Myungchul; Hwang, Yong Kee; Lee, Woong

    2012-01-01

    In order to investigate the possible reason for the improved device performances of amorphous In–Ga–Zn-O (a-IGZO) thin film transistors after thermal annealing, changes in the elemental concentrations in the a-IGZO channel regions and related device performances due to thermal annealing were observed. It was found that thermal annealing introduces a substantial level of oxygen deficiencies in the channel layer accompanying significantly enhanced device performances. The improved device performances are attributed to the oxygen deficiency which is believed to be averaged over the entire structure to function as shallow donors increasing the carrier concentrations. Such a deduction was supported by the changes in the absorption spectra of the a-IGZO films with various thermal histories. (paper)

  14. Development of the fluidized bed thermal treatment process for treating mixed waste

    International Nuclear Information System (INIS)

    Semones, G.B.; Williams, P.M.; Stiefvater, S.P.; Mitchell, D.L.; Roecker, B.D.

    1993-01-01

    A fluidized bed system is being developed at Rocky Flats for the treatment of mixed waste (a mixture of radioactive and chemically hazardous waste). The current program builds on experience gained in the 1970's and 1980's in tests with bench-scale, pilot-scale, and demonstration-scale fluidized bed systems. The system operates at low temperatures (∼ 525--600 degree C) which eliminates many of the disadvantages associated with high temperature thermal treatment processes. The process has shown the ability to destroy polychlorinated biphenyls (PCB's) with 99.9999% (''six-nines'') destruction efficiency in tests monitored by the Environmental Protection Agency (EPA). The bed makes use of in situ neutralization of acidic off-gases by incorporating sodium carbonate (Na 2 CO 3 ) in the bed media. This eliminates using wet scrubbers to treat the off-gas; these produce a high volume of secondary waste. Once in operation, it is expected that the fluidized bed process will yield up to a 40:1 reduction in the volume of the waste

  15. Efeito do tratamento térmico e enzimático nas propriedades de filmes de gelatina Effect of thermal and enzymatic treatment on the properties of gelatin films

    Directory of Open Access Journals (Sweden)

    Rosemary Aparecida de Carvalho

    2006-09-01

    /opacity of the films were evaluated. Viscosity of the solutions was also evaluated. Native film (FN, enzymatically modified film (FME and thermal treated film (FC were produced. According to the results, the temperature which was used did not significantly change the mechanical properties and the solubility of the films produced using different treatments. Enzymatically modified films at 50 °C showed the lowest water vapor permeability compared to the other temperatures and treatments (FN e FC. Thermal treatment also caused a reduction in the water vapor permeability.

  16. Analysis of simplified heat transfer models for thermal property determination of nano-film by TDTR method

    Science.gov (United States)

    Wang, Xinwei; Chen, Zhe; Sun, Fangyuan; Zhang, Hang; Jiang, Yuyan; Tang, Dawei

    2018-03-01

    Heat transfer in nanostructures is of critical importance for a wide range of applications such as functional materials and thermal management of electronics. Time-domain thermoreflectance (TDTR) has been proved to be a reliable measurement technique for the thermal property determinations of nanoscale structures. However, it is difficult to determine more than three thermal properties at the same time. Heat transfer model simplifications can reduce the fitting variables and provide an alternative way for thermal property determination. In this paper, two simplified models are investigated and analyzed by the transform matrix method and simulations. TDTR measurements are performed on Al-SiO2-Si samples with different SiO2 thickness. Both theoretical and experimental results show that the simplified tri-layer model (STM) is reliable and suitable for thin film samples with a wide range of thickness. Furthermore, the STM can also extract the intrinsic thermal conductivity and interfacial thermal resistance from serial samples with different thickness.

  17. Structure, optical properties and thermal stability of HfErO films deposited by simultaneous RF and VHF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.Y. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Nanjing University of Posts and Telecommunications, School of Tongda, Nanjing (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); He, H.J.; Zhang, Z.; Jin, C.G.; Yang, Y.; Wang, Y.Y.; Ye, C. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Zhuge, L.J. [Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Soochow University, Analysis and Testing Center, Suzhou (China); Wu, X.M. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Chinese Academy of Sciences, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Shanghai (China)

    2015-01-23

    HfErO films are deposited on Si substrates by simultaneous radio frequency (RF) and very high frequency (VHF) magnetron sputtering technique. The content of the doped ingredient of Er and the body composition of HfO{sub x} are, respectively, controlled through the VHF and RF powers. Low content of Er doping in the HfErO films can be achieved, because the VHF source of 27.12 MHz has higher ion energy and lower ion flux than the RF source resulting in low sputtering rate in the magnetron sputtering system. The structure, optical properties and thermal stability of the HfErO films are investigated in this work. Results show that the doped content of Er is independently controlled by the VHF power. The oxygen vacancies are created by the Er incorporation. The hafnium in the HfErO films forms mixed valence of Hf{sup 2+} and Hf{sup 4+}. The HfErO films are composed with the structures of HfO{sub 2}, HfO and ErO{sub x}, which can be optimized through the VHF power. At high VHF power, the Hf-Er-O bonds are formed, which demonstrates that the Er atoms are doped into the lattice of HfO{sub 2} in the HfErO films. The HfErO films have bad thermal stability as the crystallization temperature decreases from 900 to 800 C. After thermal annealing, cubic phase of HfO{sub 2} are stabilized, which is ascribed to the oxygen vacancies creation by the Er incorporation. The optical properties such as the refractive index and the optical band gap of the HfErO films are optimized by the VHF power. (orig.)

  18. Structure, optical properties and thermal stability of HfErO films deposited by simultaneous RF and VHF magnetron sputtering

    International Nuclear Information System (INIS)

    Zhang, H.Y.; He, H.J.; Zhang, Z.; Jin, C.G.; Yang, Y.; Wang, Y.Y.; Ye, C.; Zhuge, L.J.; Wu, X.M.

    2015-01-01

    HfErO films are deposited on Si substrates by simultaneous radio frequency (RF) and very high frequency (VHF) magnetron sputtering technique. The content of the doped ingredient of Er and the body composition of HfO x are, respectively, controlled through the VHF and RF powers. Low content of Er doping in the HfErO films can be achieved, because the VHF source of 27.12 MHz has higher ion energy and lower ion flux than the RF source resulting in low sputtering rate in the magnetron sputtering system. The structure, optical properties and thermal stability of the HfErO films are investigated in this work. Results show that the doped content of Er is independently controlled by the VHF power. The oxygen vacancies are created by the Er incorporation. The hafnium in the HfErO films forms mixed valence of Hf 2+ and Hf 4+ . The HfErO films are composed with the structures of HfO 2 , HfO and ErO x , which can be optimized through the VHF power. At high VHF power, the Hf-Er-O bonds are formed, which demonstrates that the Er atoms are doped into the lattice of HfO 2 in the HfErO films. The HfErO films have bad thermal stability as the crystallization temperature decreases from 900 to 800 C. After thermal annealing, cubic phase of HfO 2 are stabilized, which is ascribed to the oxygen vacancies creation by the Er incorporation. The optical properties such as the refractive index and the optical band gap of the HfErO films are optimized by the VHF power. (orig.)

  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. Evolution and change of He bubbles in He-containing Ti films upon thermal treatment studied by small-angle X-ray scattering and transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Guangai [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); College of Nuclear Science and Technology, University of Science and Technology of China, Hefei, 230029 (China); Wu, Erdong, E-mail: ewu@imr.ac.cn [National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Huang, Chaoqiang [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); College of Nuclear Science and Technology, University of Science and Technology of China, Hefei, 230029 (China); Cheng, Chun [National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Yan, Guanyun [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Wang, Xiaolin [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); College of Nuclear Science and Technology, University of Science and Technology of China, Hefei, 230029 (China); Liu, Shi [National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Tian, Qiang; Chen, Bo [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Wu, Zhonghua [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Liu, Yi; Wang, Jie [Institute of Shanghai Apply Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2014-05-02

    Evolution and change of He bubbles in magnetron sputtering prepared He-containing Ti films under thermal treatment are studied by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and X-ray diffraction. Incorporation of He introduces a large number of He-vacancy clusters and some voids in the films, and significantly increases SAXS intensity and causes anisotropic scattering. The change of He induced defects during annealing is affected by thermal diffusion and migration of trapped He to the surface and between interfaces of He induced defects within the films. Annealing at 200 and 400 °C reduces intensity and anisotropy of SAXS, in accord with observed shrinking and disappearance of the voids. The simultaneous growth of non-uniformly distributed He bubbles to the sizes of 1–2 nm and a population level of 10{sup 5}/μm{sup 3} are detected in the temperature range. The changes are explained by migration and coalescence mechanisms, which requires low apparent activation energy. Inconsistence between TEM and SAXS observations is noted and attributed to thinning induced internal stress relaxation of TEM specimen. Remarkable enlargement of He bubbles, associated with increased SAXS intensity and fractal dimension, is observed after 600 °C annealing, indicating involvement of Ostwald Ripening (OR) mechanism. The OR process dominates at 800 °C, where the high temperature provides activation energy for accelerated He dissociation from small bubbles into larger ones, and generating textured microstructure and agglomerated bubble clusters. The inhomogeneous bubble size distribution observed at this temperature covers a broad range of about 10–50 nm and possessing a population density level of 10{sup 3}/μm{sup 3}. - Highlights: • Change of He bubbles in thermally treated Ti–He films is studied by SAXS and TEM. • SAXS reveals size distribution and fractional population of He bubbles in films. • He-vacancy clusters in Ti–He film

  1. 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.)

  2. Mechanical and thermal properties of commercial multilayer PET/PP film irradiated with electron-beam

    International Nuclear Information System (INIS)

    Ortiz, Angel V.; Nogueira, Beatriz R.; Oliveira, Vitor M.; Moura, Esperidiana A.B.

    2009-01-01

    The effects of electron-beam irradiation on mechanical and thermal properties, for one commercial flexible food packaging multilayer structure, were studied. The laminated poly(ethylene terephthalate) (PET)/ polypropylene (PP) structure was irradiated up to 60 kGy, using a 1.5 MeV electron beam accelerator, at room temperature in the presence of air. Mechanical properties showed significant changes (p < 0.05). In addition, the DSC analysis, after treatment, showed that the fusion enthalpy and crystallinity of the PET/PP structure components presented significant changes (p < 0.05) with the electron-beam radiation doses applied. It was observed an increase in PP crystallinity while the PET crystallinity decreases. Such decrease in PET crystallinity indicates the predominance of a cross-linking process on the irradiated PET layer; responsible for the increase in some mechanical properties of the studied film. (author)

  3. The microstructural evolution of nanometer ruthenium films in Ru/C multilayers with thermal treatments

    International Nuclear Information System (INIS)

    Nguyen, T.D.; Gronsky, R.; Kortright, J.B.

    1991-04-01

    The evolution of nanometer Ru films sandwiched between various C layer thickness with thermal treatments was studied by plan-view and cross-sectional Transmission Electron Microscopy. Plan-view observation provides information on the Ru grain size, while cross- sectional studies allow examination of the multilayer morphology. After annealing at 800 degrees C for 30 minutes, the grain size in the 2 and 4 nm Ru layers show little difference from each other, while that in the 1 nm Ru layers depends strongly on the thickness of the C layers in the multilayers. It increases with decreasing C layer thickness. Agglomeration of the Ru layers is observed in 1nm Ru/1nm C multilayers after annealing at 600 degrees C for 30 minutes. The evolution of the microstructures and layered structure stability of the Ru/C system is compared to that of W/C and Ru/B 4 C systems. 10 refs., 2 figs

  4. 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.

  5. Layer-by-layer assembled PVA/Laponite multilayer free-standing films and their mechanical and thermal properties

    International Nuclear Information System (INIS)

    Patro, T Umasankar; Wagner, H Daniel

    2011-01-01

    Structural arrangements of nanoplatelets in a polymer matrix play an important role in determining their properties. In the present study, multilayered composite films of poly(vinyl alcohol) (PVA) with Laponite clay are assembled by layer-by-layer (LBL) deposition. The LBL films are found to be hydrated, flexible and transparent. A facile and solvent-free method—by depositing self-assembled monolayers (SMA) of a functional silane on substrates—is demonstrated for preparing free-standing LBL films. Evolution of nanostructures in LBL films is correlated with thermal and mechanical properties. A well-dispersed solvent-cast PVA/Laponite composite film is also studied for comparison. We found that structurally ordered LBL films with an intercalated nanoclay system exhibits tensile strength, modulus and toughness, which are significantly higher than that of the conventional nanocomposites with well-dispersed clay particles and that of pure PVA. This indicates that clay platelets are oriented in the applied stress direction, leading to efficient interfacial stress transfer. In addition, various grades of composite LBL films are prepared by chemical crosslinking and their mechanical properties are assessed. On account of these excellent properties, the LBL films may find potential use as optical and structural elements, and as humidity sensors.

  6. Layer-by-layer assembled PVA/Laponite multilayer free-standing films and their mechanical and thermal properties.

    Science.gov (United States)

    Patro, T Umasankar; Wagner, H Daniel

    2011-11-11

    Structural arrangements of nanoplatelets in a polymer matrix play an important role in determining their properties. In the present study, multilayered composite films of poly(vinyl alcohol) (PVA) with Laponite clay are assembled by layer-by-layer (LBL) deposition. The LBL films are found to be hydrated, flexible and transparent. A facile and solvent-free method-by depositing self-assembled monolayers (SMA) of a functional silane on substrates-is demonstrated for preparing free-standing LBL films. Evolution of nanostructures in LBL films is correlated with thermal and mechanical properties. A well-dispersed solvent-cast PVA/Laponite composite film is also studied for comparison. We found that structurally ordered LBL films with an intercalated nanoclay system exhibits tensile strength, modulus and toughness, which are significantly higher than that of the conventional nanocomposites with well-dispersed clay particles and that of pure PVA. This indicates that clay platelets are oriented in the applied stress direction, leading to efficient interfacial stress transfer. In addition, various grades of composite LBL films are prepared by chemical crosslinking and their mechanical properties are assessed. On account of these excellent properties, the LBL films may find potential use as optical and structural elements, and as humidity sensors.

  7. Effects of vacuum rapid thermal annealing on the electrical characteristics of amorphous indium gallium zinc oxide thin films

    Directory of Open Access Journals (Sweden)

    Hyun-Woo Lee

    2018-01-01

    Full Text Available We investigated the effects of vacuum rapid thermal annealing (RTA on the electrical characteristics of amorphous indium gallium zinc oxide (a-IGZO thin films. The a-IGZO films deposited by radiofrequency sputtering were subjected to vacuum annealing under various temperature and pressure conditions with the RTA system. The carrier concentration was evaluated by Hall measurement; the electron concentration of the a-IGZO film increased and the resistivity decreased as the RTA temperature increased under vacuum conditions. In a-IGZO thin-film transistors (TFTs with a bottom-gate top-contact structure, the threshold voltage decreased and the leakage current increased as the vacuum RTA temperature increased. As the annealing pressure decreased, the threshold voltage decreased, and the leakage current increased. X-ray photoelectron spectroscopy indicated changes in the lattice oxygen and oxygen vacancies of the a-IGZO films after vacuum RTA. At higher annealing temperatures, the lattice oxygen decreased and oxygen vacancies increased, which suggests that oxygen was diffused out in a reduced pressure atmosphere. The formation of oxygen vacancies increased the electron concentration, which consequently increased the conductivity of the a-IGZO films and reduced the threshold voltage of the TFTs. The results showed that the oxygen vacancies and electron concentrations of the a-IGZO thin films changed with the vacuum RTA conditions and that high-temperature RTA treatment at low pressure converted the IGZO thin film to a conductor.

  8. Effects of vacuum rapid thermal annealing on the electrical characteristics of amorphous indium gallium zinc oxide thin films

    Science.gov (United States)

    Lee, Hyun-Woo; Cho, Won-Ju

    2018-01-01

    We investigated the effects of vacuum rapid thermal annealing (RTA) on the electrical characteristics of amorphous indium gallium zinc oxide (a-IGZO) thin films. The a-IGZO films deposited by radiofrequency sputtering were subjected to vacuum annealing under various temperature and pressure conditions with the RTA system. The carrier concentration was evaluated by Hall measurement; the electron concentration of the a-IGZO film increased and the resistivity decreased as the RTA temperature increased under vacuum conditions. In a-IGZO thin-film transistors (TFTs) with a bottom-gate top-contact structure, the threshold voltage decreased and the leakage current increased as the vacuum RTA temperature increased. As the annealing pressure decreased, the threshold voltage decreased, and the leakage current increased. X-ray photoelectron spectroscopy indicated changes in the lattice oxygen and oxygen vacancies of the a-IGZO films after vacuum RTA. At higher annealing temperatures, the lattice oxygen decreased and oxygen vacancies increased, which suggests that oxygen was diffused out in a reduced pressure atmosphere. The formation of oxygen vacancies increased the electron concentration, which consequently increased the conductivity of the a-IGZO films and reduced the threshold voltage of the TFTs. The results showed that the oxygen vacancies and electron concentrations of the a-IGZO thin films changed with the vacuum RTA conditions and that high-temperature RTA treatment at low pressure converted the IGZO thin film to a conductor.

  9. Effect of thermal treatment on the CO and H2O sensing properties of MoO3 thin films

    International Nuclear Information System (INIS)

    Torres-Luengo, M; Martínez, H M; Torres, J; López-Carreño, L D

    2014-01-01

    MoO 3 thin films were prepared on Corning glass substrates using the chemical spray pyrolysis technique. A 0.1 M solution of ammonium molybdate tetrahydrate was used as precursor one. 5ml and 20 ml of the precursor solution was sprayed with the substrate temperature maintained at 623 K. Thermal treatment involved drying at 393 K for 8 h with continuous N 2 flow, followed by a vacuum annealing at 473 K for 2 h in a residual inert atmosphere. XRD indicates that the crystallographic structure corresponded to the orthorhombic α-MoO 3 phase. Electrical characterization was carried out in a system operating under high vacuum conditions. The samples could be cooled down to LN 2 temperature and heated in a controlled way up to 473 K. To elucidate the electrical response of the films to CO and H 2 O exposure, the I-V characteristic curve was measured over the whole temperature range. The electrical resistance of the films decreased with increasing temperature. In 5 ml films, the sensitivity to both gases increased which thermal treatment, reaching values between 40% and 60% at room temperature. On the contrary, the 20 ml films' sensitivity decreased almost half of their original values after thermal treatment

  10. Thermal and rheological properties of L-polylactide/polyethylene glycol/silicate nanocomposites films.

    Science.gov (United States)

    Ahmed, Jasim; Varshney, Sunil K; Auras, Rafael; Hwang, Sung W

    2010-10-01

    The melt rheology and thermal properties of polylactide (PLA)-based nanocomposite films that were prepared by solvent casting method with L-PLA, polyethylene glycol (PEG), and montmorillonite clay were studied. The neat PLA showed predominantly solid-like behavior (G' > G″) and the complex viscosity (η*) decreased systematically as the temperature increased from 184 to 196 °C. The elastic modulus (G') of PLA/clay blend showed a significant improvement in the magnitude in the melt, while clay concentration was at 6% wt or higher. At similar condition, PEG dramatically reduced dynamic modulii and complex viscosity of PLA/PEG blend as function of concentration. A nanocomposite blend of PLA/PEG/clay (74/20/6) when compared to the neat polymer and PLA/PEG blend exhibited intermediate values of elastic modulus (G') and complex viscosity (η*) with excellent flexibility. Thermal analysis of different clay loading blends indicated that the melting temperature (T(m)) and glass transition temperature (T(g)) remained unaffected irrespective of clay concentration due to immobilization of polymer chain in the clay nanocomposite. PEG incorporation reduced the T(g) and the T(m) of the blends (PLA/PEG and PLA/PEG/clay) significantly, however, crystallinity increased in the similar condition. The transmission electron microscopy (TEM) image of nanocomposite films indicated good compatibility between PLA and PEG, whereas clay was not thoroughly distributed in the PLA matrix and remained as clusters. The percent crystallinity obtained by X-ray was significantly higher than that of differential scanning calorimeter (DSC) data for PLA.

  11. Thermal desorption spectroscopy of boron/carbon films after keV deuterium irradiation

    International Nuclear Information System (INIS)

    Yamaki, T.; Gotoh, Y.; Ando, T.; Jimbou, R.; Ogiwara, N.; Saidoh, M.

    1994-01-01

    Thermal desorption spectroscopy (TDS) of D 2 and CD 4 was done on boron/carbon films (B/(B+C)=0-74%), after 3 keV D 3 + irradiation to 4.5x10 17 D/cm 2 at 473 K. The D 2 desorption peaks were observed at 1050, 850 and 650 K. For a sputter B/C film (0%), only the 1050 K peak was observed. With increasing boron concentration to 3%, a sharp peak appeared at 850 K, the intensity of which was found to increase with increasing boron concentration to 23%, and then to decrease at 74%. The 650 K shoulder, which was observed for high boron concentration specimens, was speculated to be deuterium trapped by boron atoms in the boron clusters. The relative amount of CD 4 desorption was found to decrease with increasing boron concentration, which was attributed to the decrease in the trapped deuterium concentration in the implantation layer at temperatures at which CD 4 desorption proceeds. ((orig.))

  12. Thermal stability of Ti{sub 3}SiC{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Emmerlich, Jens [Linkoeping University, Department of Physics, IFM, Thin Film Physics Division, SE-581 83 Linkoeping (Sweden)]. E-mail: jenem@ifm.liu.se; Music, Denis [Materials Chemistry, RWTH Aachen University, Kopernikusstrasse 16, D-52074 Aachen (Germany); Eklund, Per [Linkoeping University, Department of Physics, IFM, Thin Film Physics Division, SE-581 83 Linkoeping (Sweden); Wilhelmsson, Ola [Uppsala University, Department of Materials Chemistry, The Angstroem Laboratory, P.O. Box 538, SE-751 21 Uppsala (Sweden); Jansson, Ulf [Uppsala University, Department of Materials Chemistry, The Angstroem Laboratory, P.O. Box 538, SE-751 21 Uppsala (Sweden); Schneider, Jochen M. [Materials Chemistry, RWTH Aachen University, Kopernikusstrasse 16, D-52074 Aachen (Germany); Hoegberg, Hans [Linkoeping University, Department of Physics, IFM, Thin Film Physics Division, SE-581 83 Linkoeping (Sweden); Hultman, Lars [Linkoeping University, Department of Physics, IFM, Thin Film Physics Division, SE-581 83 Linkoeping (Sweden)

    2007-02-15

    The thermal stability of Ti{sub 3}SiC{sub 2}(0 0 0 1) thin films is studied by in situ X-ray diffraction analysis during vacuum furnace annealing in combination with X-ray photoelectron spectroscopy, transmission electron microscopy and scanning transmission electron microscopy with energy dispersive X-ray analysis. The films are found to be stable during annealing at temperatures up to {approx}1000 deg. C for 25 h. Annealing at 1100-1200 deg. C results in the rapid decomposition of Ti{sub 3}SiC{sub 2} by Si out-diffusion along the basal planes via domain boundaries to the free surface with subsequent evaporation. As a consequence, the material shrinks by the relaxation of the Ti{sub 3}C{sub 2} slabs and, it is proposed, by an in-diffusion of O into the empty Si-mirror planes. The phase transformation process is followed by the detwinning of the as-relaxed Ti{sub 3}C{sub 2} slabs into (1 1 1)-oriented TiC{sub 0.67} layers, which begin recrystallizing at 1300 deg. C. Ab initio calculations are provided supporting the presented decomposition mechanisms.

  13. Thermal stability of Ti3SiC2 thin films

    International Nuclear Information System (INIS)

    Emmerlich, Jens; Music, Denis; Eklund, Per; Wilhelmsson, Ola; Jansson, Ulf; Schneider, Jochen M.; Hoegberg, Hans; Hultman, Lars

    2007-01-01

    The thermal stability of Ti 3 SiC 2 (0 0 0 1) thin films is studied by in situ X-ray diffraction analysis during vacuum furnace annealing in combination with X-ray photoelectron spectroscopy, transmission electron microscopy and scanning transmission electron microscopy with energy dispersive X-ray analysis. The films are found to be stable during annealing at temperatures up to ∼1000 deg. C for 25 h. Annealing at 1100-1200 deg. C results in the rapid decomposition of Ti 3 SiC 2 by Si out-diffusion along the basal planes via domain boundaries to the free surface with subsequent evaporation. As a consequence, the material shrinks by the relaxation of the Ti 3 C 2 slabs and, it is proposed, by an in-diffusion of O into the empty Si-mirror planes. The phase transformation process is followed by the detwinning of the as-relaxed Ti 3 C 2 slabs into (1 1 1)-oriented TiC 0.67 layers, which begin recrystallizing at 1300 deg. C. Ab initio calculations are provided supporting the presented decomposition mechanisms

  14. Morphology, thermal, mechanical, and barrier properties of graphene oxide/poly(lactic acid) nanocomposite films

    International Nuclear Information System (INIS)

    Kim, Seong Woo; Choi, Hyun Muk

    2016-01-01

    To improve the physical and gas barrier properties of biodegradable poly(lactic acid) (PLA) film, two graphene nanosheets of highly functionalized graphene oxide (0.3 wt% to 0.7 wt%) and low-functionalized graphene oxide (0.5 wt%) were incorporated into PLA resin via solution blending method. Subsequently, we investigated the effects of material parameters such as loading level and degree of functionalization for the graphene nanosheets on the morphology and properties of the resultant nanocomposites. The highly functionalized graphene oxide (GO) caused more exfoliation and homogeneous dispersion in PLA matrix as well as more sustainable suspensions in THF, compared to low-functionalized graphene oxide (LFGO). When loaded with GO from 0.3 wt% to 0.7 wt%, the glass transition temperature, degree of crystallinity, tensile strength and modulus increased steadily. The GO gave rise to more pronounced effect in the thermal and mechanical reinforcement, relative to LFGO. In addition, the preparation of fairly transparent PLA-based nanocomposite film with noticeably improved barrier performance achieved only when incorporated with GO up to 0.7wt%. As a result, GO may be more compatible with hydrophilic PLA resin, compared to LFGO, resulting in more prominent enhancement of nanocomposites properties.

  15. Thermal stability of electrical properties of ZnO:Al films deposited by room temperature magnetron sputtering

    International Nuclear Information System (INIS)

    Wang Tao; Diao Xungang; Ding Peng

    2011-01-01

    Research highlights: → Real-time sheet resistance (R s ) of ZnO:Al films heated in Ar gas was measured by a dada capturer. → Results revealed that R s of the film heated at 100 o C was reduced throughout the annealing. → R s of the films annealed over 100 o C was reduced at early stage but then increased all along to the end. → Some novel R s change points that need more penetrations were detected by the self designed capturer. - Abstract: In order to investigate the thermal stability of electrical properties for aluminum doped zinc oxide (ZnO:Al, AZO) films deposited by direct current reactive magnetron sputtering, AZO films deposited from an alloy target (0.8 wt.% Al) on soda-lime glasses were annealed in argon gas at different temperatures. A data capturer was applied to monitor and collect real-time sheet resistance (R s ) of the films throughout the annealing. Results revealed that R s of the film heated at 100 o C was reduced throughout the annealing, however, conductivity of the films annealed over 100 o C was improved at early stage but then deteriorated all along to the end. Some novel R s change points which need more penetrations were detected. The experimental results obtained from electron diffraction spectrum, X-ray diffraction pattern, X-ray photoelectron spectrum, and Hall measurement were analyzed to explore the effect of the annealing on the electrical properties of AZO films. It was found that the exotic element, which might influence the film properties, was not observed. It was also suggested that the transformation of the crystalline structure and surface chemical bonding states, which resulted in the decrease of carrier concentration and mobility could be the reason for the conductivity degeneration of the films annealed at higher temperature.

  16. Cooling Effectiveness Measurements for Air Film Cooling of Thermal Barrier Coated Surfaces in a Burner Rig Environment Using Phosphor Thermometry

    Science.gov (United States)

    Eldridge, Jeffrey I.; Shyam, Vikram; Wroblewski, Adam C.; Zhu, Dongming; Cuy, Michael D.; Wolfe, Douglas E.

    2016-01-01

    While the effects of thermal barrier coating (TBC) thermal protection and air film cooling effectiveness are usually studied separately, their contributions to combined cooling effectiveness are interdependent and are not simply additive. Therefore, combined cooling effectiveness must be measured to achieve an optimum balance between TBC thermal protection and air film cooling. In this investigation, surface temperature mapping was performed using recently developed Cr-doped GdAlO3 phosphor thermometry. Measurements were performed in the NASA GRC Mach 0.3 burner rig on a TBC-coated plate using a scaled up cooling hole geometry where both the mainstream hot gas temperature and the blowing ratio were varied. Procedures for surface temperature and cooling effectiveness mapping of the air film-cooled TBC-coated surface are described. Applications are also shown for an engine component in both the burner rig test environment as well as an engine afterburner environment. The effects of thermal background radiation and flame chemiluminescence on the measurements are investigated, and advantages of this method over infrared thermography as well as the limitations of this method for studying air film cooling are discussed.

  17. Insights into the stability and thermal degradation of P3HT:C60 blended films for solar cell applications

    CSIR Research Space (South Africa)

    Motaung, DE

    2011-03-01

    Full Text Available This paper demonstrates the changes in the nanoscale morphology of the blended films induced by a diffusion of C60 molecules and degradation during longer thermal treatment above the glass transition temperature (130 °C). The results showed...

  18. Effect of electron beam irradiation on structural and thermal properties of gamma poly (vinylidene fluoride) (γ-PVDF) films

    Science.gov (United States)

    Tan, Zhongyang; Wang, Xuemei; Fu, Chao; Chen, Chunhai; Ran, Xianghai

    2018-03-01

    In this study, we successfully prepared the pure PVDF film containing almost exclusive γ-phase (γ-PVDF) using 15 wt% solution in N, N-dimethylformamide. These γ-PVDF films were irradiated by 3.0 MeV electron beam in vacuum at room temperature up to 358 kGy. The effect of the irradiation on the chemical structural and thermal properties of pristine and irradiated γ-PVDF films were detailedly investigated by FTIR, XRD and DSC, respectively. DSC results show that two single and different melting endotherms from the successive heating curves correspond to γ-phase and α-phase, respectively. FTIR results show that the characteristic absorption peaks corresponding to γ-phase do not shift, and the C˭C bond formation is not significantly observed in the irradiated γ-PVDF films until above 30 kGy. XRD results show that the crystal form of γ-PVDF is not influenced significantly by irradiation. All PVDF films exhibit a single melting endotherm, irrespective of the irradiation dose. Two superpositioned crystallization peaks were observed for PVDF films only irradiated at high dose of 232 and 358 kGy, which can be related to the fractionated crystallization of irradiated PVDF. The dependences of thermal characteristics on the irradiation dose were detailedly investigated by DSC in this study.

  19. 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.

  20. Determination of structural and mechanical properties, diffractometry, and thermal analysis of chitosan and hydroxypropylmethylcellulose (HPMC films plasticized with sorbitol

    Directory of Open Access Journals (Sweden)

    Jefferson Rotta

    2011-06-01

    Full Text Available In this work, the structural, mechanical, diffractometric, and thermal parameters of chitosan-hydroxypropylmethylcellulose (HPMC films plasticized with sorbitol were studied. Solutions of HPMC (2% w/v in water and chitosan (2% w/v in 2% acetic acid solution were prepared. The concentration of sorbitol used was 10% (w/w to both polymers. This solutions were mixed at different proportions (100/0; 70/30; 50/50; 30/70, and 0/100 of chitosan and HPMC, respectively, and 20 mL was cast in Petri dishes for further analysis of dried films. The miscibility of polymers was assessed by X-ray diffraction, scanning electronic microscopy (SEM, differential scanning calorimetry (DSC, and thermal gravimetric analysis (TGA. The results obtained indicate that the films are not fully miscible at a dry state despite the weak hydrogen bonding between the polymer functional groups.

  1. Effect of layered silicate content on the morphology and thermal properties of Poly(vinyl alcohol) films

    International Nuclear Information System (INIS)

    Silva, Jessica R.M.B. da; Santos, Barbara F.F. dos; Leite, Itamara F.

    2015-01-01

    This study aims to evaluate the effect of layered silicate content on the morphology and thermal properties of PVA films. The PVA/layered silicate (AN) films were prepared by intercalation solution, using 1 to 2% of bentonite with respect to the PVA total weight. Then the films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). Results of the FTIR revealed interaction between the functional groups of the PVA and the layered silicate. The XRD analysis showed that nanocomposites with intercalated and partially exfoliated morphology were obtained. The results of TG showed that the nanocomposite PVA/2%AN showed higher thermal stability compared to PVA/1%AN. The DSC results showed that the addition of AN to the PVA did not affect crystallization rate, as well as promoted a reduction in glass transition temperature and melting of the PVA. (author)

  2. Enhanced thermoelectric properties of PEDOT/PSS/Te composite films treated with H2SO4

    International Nuclear Information System (INIS)

    Song, Haijun; Cai, Kefeng; Shen, Shirley

    2016-01-01

    Firstly, tellurium (Te) nanorods with a high Seebeck coefficient have been integrated into a conducting polymer PEDOT/PSS to form PEDOT/PSS/Te composite films. The Seebeck coefficient of the PEDOT/PSS/Te (90 wt.%) composite films is ~191 μV/K, which is about 13 times greater than that of pristine PEDOT/PSS. Then, H 2 SO 4 treatment has been used to further tune the thermoelectric properties of the composite films by adjusting the doping level and increasing the carrier concentration. After the acid treatment, the electrical conductivity of the composite films has increased from 0.22 to 1613 S/cm due to the removal of insulating PSS and the structural rearrangement of PEDOT. An optimized power factor of 42.1 μW/mK 2 has been obtained at room temperature for a PEDOT/PSS/Te (80 wt.%) sample, which is about ten times larger than that of the untreated PEDOT/PSS/Te composite film.

  3. Influence of boat material on the structure, stoichiometry and optical properties of gallium sulphide films prepared by thermal evaporation

    International Nuclear Information System (INIS)

    Rao, Pritty; Kumar, Sanjiv; Sahoo, N.K.

    2015-01-01

    The paper describes the deposition of thin films of gallium sulphide on soda-lime glass substrates by thermal evaporation of chemically synthesized powders consisting of gallium sulphide and gallium oxyhydroxide from a Mo or Ta boat and the evolution of their compositional, structural and optical properties on vacuum annealing. The films deposited from Mo or Ta boats possessed distinctly different properties. The Mo-boat evaporated pristine films were amorphous, transparent (α ∼ 10 3  cm −1 ) in visible region and had a direct band gap of about 3.2 eV. Vacuum annealing at 723 K brought about their crystallization predominantly into cubic γ-Ga 2 S 3 and a blue shift by about 0.2 eV. The Ta-boat evaporated pristine films were also amorphous but were absorbing (α ∼ 10 4  cm −1 ) and had a direct band gap of about 2.1 eV. These crystallized into hexagonal GaS and experienced a blue shift by more than 1.0 eV on vacuum annealing at 723 K. The dissimilar properties of the two kinds of films arose mainly from their different atomic compositions. The Mo-boat evaporated pristine films contained Ga and S in ∼1:1 atomic proportions while those prepared using Ta-boat were Ga rich which impaired their transmission characteristics. The former composition favoured the stabilization of S rich gallium sulphide (Ga 2 S 3 ) phase while the latter stabilised S deficient species, GaS. Besides inducing crystallization, vacuum annealing at 723 K also caused the diffusion of Ga in excess of atomic composition of the phase formed, into soda-lime glass which improved the optical transmission of the films. Gallium oxyhydroxide, an inevitable co-product of the chemical synthetic process, in the evaporant introduced oxygen and hydrogen impurities in the films which do not seem to significantly influence their optical properties. - Highlights: • Gallium sulphide films are prepared by thermal evaporation from a Mo or Ta boat. • Mo-boat prepared pristine film has Ga

  4. Electrically and thermally activated ageing mechanisms in metallised polymer film capacitors

    International Nuclear Information System (INIS)

    Lee, Yuen Pen

    2001-01-01

    This dissertation describes a combined computational and experimental study to understand the fundamental electrostatic, thermal, electromagnetic, and discharge related processes during the ageing of metallised polymer film capacitors. In the event of internal breakdowns, these capacitors are capable of 'self-healing' through a controlled isolation of defects on the electrode surfaces by mosaic patterning the electrode. The objective of this project is to develop viable computer models to unravel electrothermally activated ageing processes in capacitors. To provide the necessary validation to any capacitor models developed, our work is supported by comprehensive experiments including industrial standard accelerated life tests and associated breakdown damage analyses of tested capacitors. These have enabled an empirical identification of main factors affecting the reliability and lifetime of capacitors. Relevant raw data and the qualitative picture enabled by these data are crucial to the development and refinement of viable computational models of capacitors. Given the complexity of ageing processes, it is both very difficult and unnecessary to develop a one-for-all model that describes indiscriminately all relevant processes. The approach adapted in this work has been to prioritise key ageing processes and modularise each process with its own computer model. The overall picture of capacitor ageing can then be unravelled by integrating all modules together. For instance, the fine geometrical features of the electrode mosaic pattern and the capacitor's laminated structure have been assessed through a concept of field intensification using a 2D electrostatic finite element computation. With fine geometrical features accounted for by the field intensification concept, fast electric events in capacitors can be simulated using a simple equivalent circuit model. Similar assessment of heat transfer has led to an equally efficient modelling of thermal events in capacitors

  5. Thermal oxidation effect on structural and optical properties of heavily doped phosphorus polycrystalline silicon films

    Energy Technology Data Exchange (ETDEWEB)

    Birouk, B.; Madi, D. [Universite de Jijel, Laboratoire d' Etudes et de Modelisation en Electrotechnique (LAMEL), Cite Ouled Aissa, BP 98, Jijel (Algeria)

    2011-08-15

    The study reported in this paper contributes to better understanding the thermal oxidation effect on structural and optical properties of polycrystalline silicon heavily in situ P-LPCVD films. The deposits, doped at levels 3 x 10{sup 19} and 1.6 x 10{sup 20} cm{sup -3}, have been elaborated from silane decomposition (400 mTorrs, 605 C) on monosilicon substrate oriented left angle 111 right angle. The thermal oxidation was performed at temperatures: 850 C during 1 hour, 1000, 1050, and 1100 C during 15 minutes. The XRD spectra analysis pointed out significant left angle 111 right angle texture evolution, while in the case of left angle 220 right angle and left angle 311 right angle textures, the intensities are practically invariant (variations fall in the uncertainty intervals). The optical characterizations showed that refractive index and absorption coefficient are very sensitive to the oxidation treatment, mainly when the doping level is not very high. We think that atomic oxygen acts as defects passivating agent leading to carriers' concentration increasing. Besides, the optical behavior is modeled in visible and near infrared, by a seven-term polynomial function n {sup 2}=f({lambda} {sup 2}), with alternate signs, instead of theoretically unlimited terms number from Drude's model. It has been shown that fitting parameters fall on Gaussian curves like they do in the theoretical model. (orig.)

  6. 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

  7. Comparison between thermal annealing and ion mixing of multilayered Ni-W films on Si. II

    International Nuclear Information System (INIS)

    Pai, C.S.; Lau, S.S.; Poker, D.B.; Hung, L.S.

    1985-01-01

    The reactions between bilayered Ni/W films and Si substrates induced by thermal annealing and ion mixing were investigated and compared. Samples were prepared by electron-beam sequential deposition of Ni and W onto the Si substrates and following by either furnace annealing (approx. 200--900 0 C) or ion mixing (approx. 2 x 10 15 -- 4 x 10 16 86 Kr + ions/cm 2 ). The reactions were analyzed by Rutherford backscattering and x-ray diffraction (Read camera). Thermal annealing of both W/Ni/Si and Ni/W/Si samples led to the formation of Ni silicide next to the Si substrate and W silicide on the sample surface (layer reversal between Ni and W in the Ni/W/Si case). Ion mixing of W/Ni/Si samples led to the formation of Ni silicide with a thin layer of Ni-W-Si mixture located at the sample surface. For Ni/W/Si samples a ternary amorphous mixture of Ni-W-Si was obtained with ion mixing. These reactions were rationalized in terms of the mobilities of various atoms and the intermixings between layers

  8. Enhanced linear and nonlinear optical properties of thermally stable ZnO/poly(styrene)–poly(methyl methacrylate) nanocomposite films

    International Nuclear Information System (INIS)

    Jeeju, P.P.; Jayalekshmi, S.; Chandrasekharan, K.; Sudheesh, P.

    2013-01-01

    Highly transparent and thermally stable zinc oxide (ZnO)/poly(styrene)–poly(methyl methacrylate) (PS–PMMA) nanocomposite films have been deposited on glass substrates, from the ZnO incorporated (PS–PMMA) solutions in toluene, using spin coating technique. A chemical route at room temperature is used to synthesize the ZnO nanoparticles. Transmission electron microscope and high-resolution transmission electron microscope images show that the ZnO nanoparticles are of size around 10 nm. The composite films have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy, Ultraviolet–visible–Near Infrared (UV–vis–NIR) spectroscopy, Thermo-gravimetric analysis, photoluminescence (PL) spectroscopy and Z-scan technique. From the UV–vis–NIR spectra it is observed that the ZnO/PS–PMMA nanocomposite films with 10 wt.% ZnO content exhibit excellent shielding property in the UV region and, high transparency in the visible region. The PL spectrum of the composite films is different from that of ZnO and PS–PMMA blend and exhibits an excitonic emission peak at ∼ 375 nm. The optical absorptive nonlinearity in the nanocomposite films is investigated using open aperture Z-scan technique. The results indicate optical limiting type nonlinearity in the films due to two photon absorption. A transmittance minimum of around 0.25 has been observed in the ZnO/PS–PMMA nanocomposite films which is much lower compared to that in ZnO/PMMA and ZnO/PS nanocomposite films. The ZnO/PS–PMMA nanocomposite films also show a self-defocusing type negative nonlinear refraction in closed aperture Z-scan experiment. These nanocomposite films extend ample scope of applications as excellent optical limiters and efficient UV protectors. - Highlights: ► Transparent, ZnO/poly(styrene)–poly(methyl methacrylate) composite films are prepared. ► The nanocomposite films with 10 wt.% ZnO content exhibit good UV-shielding property.

  9. Enhanced linear and nonlinear optical properties of thermally stable ZnO/poly(styrene)–poly(methyl methacrylate) nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Jeeju, P.P., E-mail: jeejupp@gmail.com [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Kochi 682 022, Kerala (India); Jayalekshmi, S., E-mail: jayalekshmi@cusat.ac.in [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Kochi 682 022, Kerala (India); Chandrasekharan, K.; Sudheesh, P. [Department of Physics, National Institute of Technology, Calicut, Kerala (India)

    2013-03-01

    Highly transparent and thermally stable zinc oxide (ZnO)/poly(styrene)–poly(methyl methacrylate) (PS–PMMA) nanocomposite films have been deposited on glass substrates, from the ZnO incorporated (PS–PMMA) solutions in toluene, using spin coating technique. A chemical route at room temperature is used to synthesize the ZnO nanoparticles. Transmission electron microscope and high-resolution transmission electron microscope images show that the ZnO nanoparticles are of size around 10 nm. The composite films have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy, Ultraviolet–visible–Near Infrared (UV–vis–NIR) spectroscopy, Thermo-gravimetric analysis, photoluminescence (PL) spectroscopy and Z-scan technique. From the UV–vis–NIR spectra it is observed that the ZnO/PS–PMMA nanocomposite films with 10 wt.% ZnO content exhibit excellent shielding property in the UV region and, high transparency in the visible region. The PL spectrum of the composite films is different from that of ZnO and PS–PMMA blend and exhibits an excitonic emission peak at ∼ 375 nm. The optical absorptive nonlinearity in the nanocomposite films is investigated using open aperture Z-scan technique. The results indicate optical limiting type nonlinearity in the films due to two photon absorption. A transmittance minimum of around 0.25 has been observed in the ZnO/PS–PMMA nanocomposite films which is much lower compared to that in ZnO/PMMA and ZnO/PS nanocomposite films. The ZnO/PS–PMMA nanocomposite films also show a self-defocusing type negative nonlinear refraction in closed aperture Z-scan experiment. These nanocomposite films extend ample scope of applications as excellent optical limiters and efficient UV protectors. - Highlights: ► Transparent, ZnO/poly(styrene)–poly(methyl methacrylate) composite films are prepared. ► The nanocomposite films with 10 wt.% ZnO content exhibit good UV-shielding property.

  10. Calibration of photographic and spectroscopic films. 1: Film batch variations of reciprocity failure in IIaO film. 2: Thermal and aging effects in relationship to reciprocity failure. 3: Shifting of reciprocity failure points as a function of thermal and aging effects. Semiannual report, December 1986

    International Nuclear Information System (INIS)

    Peters, K.A.; Atkinson, P.F.; Hammond, E.C. Jr.

    1986-01-01

    Reciprocity failure was examined for IIaO spectroscopic film. Three separate experiments were performed in order to study film batch variations, thermal and aging effects in relationship to reciprocity failure, and shifting of reciprocity failure points as a function of thermal and aging effects. The failure was examined over ranges of time between 5 and 60 seconds. The variation to illuminance was obtained by using thirty neutral density filters. A standard sensitometer device imprinted the wedge pattern on the film as exposure time was subjected to variation. The results indicate that film batch differences, temperature, and aging play an important role in reciprocity failure of IIaO spectroscopic film. A shifting of the failure points was also observed in various batches of film

  11. In situ monitoring of thermal crystallization of ultrathin tris(8-hydroxyquinoline) aluminum films using surface-enhanced Raman scattering.

    Science.gov (United States)

    Muraki, Naoki

    2014-01-01

    Thermal crystallization of 3, 10, and 60 nm-thick tris(8-hydroxyquinoline)aluminum (Alq3) films is studied using surface-enhanced Raman scattering with a constant heating rate. An abrupt higher frequency shift of the quinoline-stretching mode is found to be an indication of a phase transition of Alq3 molecules from amorphous to crystalline. While the 60 nm-thick film shows the same crystallization temperature as a bulk sample, the thinner films were found to have a lower crystallization temperature and slower rate of crystallization. Non-isothermal kinetics analysis is performed to quantify kinetic properties such as the Avrami exponent constants and crystallization rates of ultrathin Alq3 films.

  12. Effects of hydrogenation on thermal conductivity of ultrananocrystalline diamond/amorphous carbon composite films prepared via coaxial arc plasma deposition

    Science.gov (United States)

    Takeichi, Satoshi; Nishiyama, Takashi; Tabara, Mitsuru; Kawawaki, Shuichi; Kohno, Masamichi; Takahashi, Koji; Yoshitake, Tsuyoshi

    2018-06-01

    Ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite (UNCD/a-C:H) and UNCD/non-hydrogenated amorphous carbon (a-C) composite (UNCD/a-C) films were prepared via coaxial arc plasma deposition, and their thermal conductivity and interfacial conductance in grain boundaries were measured using a time-domain thermoreflectance method. The interfacial conductance was estimated to be 1,010 and 4,892 MW/(m2·K) for UNCD/a-C:H and UNCD/a-C films, respectively. The reasons for the hydrogenated film having lower interfacial conductance than the non-hydrogenated film are 1) the reduced number of carriers that contribute to heat transport and 2) the hydrogen atoms, which are preferentially located at the grain boundaries and enhance phonon scattering.

  13. Effect of low thermal budget annealing on surface passivation of silicon by ALD based aluminum oxide films.

    Science.gov (United States)

    Vandana; Batra, Neha; Gope, Jhuma; Singh, Rajbir; Panigrahi, Jagannath; Tyagi, Sanjay; Pathi, P; Srivastava, S K; Rauthan, C M S; Singh, P K

    2014-10-21

    Thermal ALD deposited Al2O3 films on silicon show a marked difference in surface passivation quality as a function of annealing time (using a rapid thermal process). An effective and quality passivation is realized in short anneal duration (∼100 s) in nitrogen ambient which is reflected in the low surface recombination velocity (SRV passivation. Both as-deposited and low thermal budget annealed films show the presence of positive fixed charges and this is never been reported in the literature before. The role of field and chemical passivation is investigated in terms of fixed charge and interface defect densities. Further, the importance of the annealing step sequence in the MIS structure fabrication protocol is also investigated from the view point of its effect on the nature of fixed charges.

  14. Effect of thermal annealing on the properties of transparent conductive In–Ga–Zn oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ling [Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049, China and School of Information Science and Engineering, Shandong University, Jinan 250100 (China); Fan, Lina; Li, Yanhuai; Song, Zhongxiao; Ma, Fei, E-mail: mafei@mail.xjtu.edu.cn, E-mail: chlliu@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Chunliang, E-mail: mafei@mail.xjtu.edu.cn, E-mail: chlliu@mail.xjtu.edu.cn [Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China)

    2014-03-15

    Amorphous In–Ga–Zn oxide (IGZO) thin films were prepared using radio frequency magnetron sputtering at room temperature. Upon thermal annealing at temperatures even up to 500 °C, the amorphous characteristics were still maintained, but the electronic properties could be considerably enhanced. This could be ascribed to the increased optical band gap and the increased oxygen vacancies, as corroborated by the microstructure characterizations. In addition, the surface became smoother upon thermal annealing, guaranteeing good interface contact between electrode and a-IGZO. The optical transmittance at 400–800 nm exceeded 90% for all samples. All in all, thermal annealing at appropriate temperatures is expected to improve the performances of relevant a-IGZO thin film transistors.

  15. New Copolymers Containing Charge Carriers for Organic Devices with ITO Films Treated by UV-Ozone Using High Intensity Discharge Lamp

    Directory of Open Access Journals (Sweden)

    Emerson Roberto SANTOS

    2009-02-01

    Full Text Available For electroluminescent devices new copolymers were synthesized using a Suzuki cross-coupling reaction based on monomers (fluorine-alt-phenylene in conjugation with quinoline-alt-phenylene units. They were characterized by 1H NMR, 13C NMR and FTIR. TGA measurements indicated that the copolymers have good thermal properties and no weight loss was observed up to 250 °C. The UV-Vis spectra were characterized by absorptions from the fluorene-alt-phenylene and quinoline-alt-phenylene segments in the backbone, while their photoluminescence (PL spectra dominated by emissions from the fluorene excimer. For devices assembly ITO films were treated using a High Intensity Discharge Lamp (HPMVL without outer bulb presenting high ozone concentration than that conventional germicidal lamp. The device with ITO treated revealed significant decrease of threshold voltage (or turn-on voltage compared by untreated with I-V curves. This decrease can be related by water and carbon dioxide extracted on surface after UV-Ozone treatment revealed by DRIFT measurements.

  16. Strongly anisotropic thermal conductivity and adequate breathability of bilayered films for heat management of on-skin electronics

    Science.gov (United States)

    Zhou, Tianle; Wei, Hao; Tan, Huaping; Wang, Xin; Zeng, Haibo; Liu, Xiaoheng; Nagao, Shijo; Koga, Hirotaka; Nogi, Masaya; Sugahara, Tohru; Suganuma, Katsuaki

    2018-07-01

    Thin-film wearable electronics are required to be directly laminated on to human skin for reliable, sensitive bio-sensing but with minimal irritation to the user after long-time use. Excellent heat management films with strongly anisotropic thermal conductivity (K) and adequate breathability are increasingly desirable for shielding the skin from heating while allowing the skin to breathe properly. Here, interfacial self-assembly of a graphene oxide (GO) film covering an ambient-dried bacterial cellulose aerogel (AD-BCA) film followed by laser reduction was proposed to prepare laser-reduced GO (L-rGO)/AD-BCA bilayered films. The AD-BCA substrate provides low cross-plane K (K ⊥  ≈  0.052 W mK‑1), high breathability, and high compressive and tensile resistance by ‘partially’ inheriting the pore structure from bacterial cellulose (BC) gel. The introduction of an upper L-rGO film, which is only 0.31 wt% content, dramatically increases the in-plane K (K // ) from 0.3 W mK‑1 in AD-BCA to 10.72 W mK‑1 owing to the highly in-plane oriented, continuous, uniform assembling geometry of the GO film; while K ⊥ decreases to a lower value of 0.033 W mK‑1, mainly owing to the air pockets between L-rGO multilayers caused by the laser reduction. The bilayered films achieve a K // /K ⊥ of 325, which is substantially larger even than that of graphite and similar polymer composites. They permit high transmission rates for water vapor (416.78 g/m2/day, >204 g/m2/day of normal skin) and O2 (449.35 cm3/m2/day). The combination of strongly anisotropic thermal conductivity and adequate breathability facilitates applications in heat management in on-skin electronics.

  17. Thermal properties of milk fat, xanthine oxidase, caseins and whey proteins in pulsed electric field-treated bovine whole milk.

    Science.gov (United States)

    Sharma, Pankaj; Oey, Indrawati; Everett, David W

    2016-09-15

    Thermodynamics of milk components (milk fat, xanthine oxidase, caseins and whey proteins) in pulsed electric field (PEF)-treated milk were compared with thermally treated milk (63 °C for 30 min and 73 °C for 15s). PEF treatments were applied at 20 or 26 kV cm(-1) for 34 μs with or without pre-heating of milk (55 °C for 24s), using bipolar square wave pulses in a continuous mode of operation. PEF treatments did not affect the final temperatures of fat melting (Tmelting) or xanthine oxidase denaturation (Tdenaturation), whereas thermal treatments increased both the Tmelting of milk fat and the Tdenaturation for xanthine oxidase by 2-3 °C. Xanthine oxidase denaturation was ∼13% less after PEF treatments compared with the thermal treatments. The enthalpy change (ΔH of denaturation) of whey proteins decreased in the treated-milk, and denaturation increased with the treatment intensity. New endothermic peaks in the calorimetric thermograms of treated milk revealed the formation of complexes due to interactions between MFGM (milk fat globule membrane) proteins and skim milk proteins. Evidence for the adsorption of complexes onto the MFGM surface was obtained from the increase in surface hydrophobicity of proteins, revealing the presence of unfolded hydrophobic regions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Structural, morphological, wettability and thermal resistance properties of hydro-oleophobic thin films prepared by a wet chemical process

    International Nuclear Information System (INIS)

    Phani, A.R.

    2006-01-01

    The structural properties of fluorine containing polymer compounds make them highly attractive materials for hydro-oleophobic applications. However, most of these exhibit low surface energy and poor adhesion on the substrates. In the present investigation, crack free, smooth and uniform thin films of poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole] -co-tetrafluoroethylene (TFD-co-TFE) with good adhesion have been deposited by wet chemical spin-coating technique on polished AISI 440C steel substrates. The as-deposited films (xerogel films) have been subjected to annealing for 1 h at different temperatures ranging from 100 to 500 deg. C in an argon atmosphere. The size growth of the nano-hemispheres increased from 8 nm for xerogel film to 28 nm for film annealed at 400 deg. C. It was found that as the annealing temperature increased from 100 to 400 deg. C, nano-hemisphere-like structures were formed, which in turn have shown increase in the water contact angle from 122 deg. to 147 deg. and oil (peanut) contact angle from 85 deg. to 96 deg. No change in the water contact angle (122 deg.) has been observed when the films deposited at room temperature were heated in air from 30 to 80 deg. C as well as exposed to steam for 8 days for 8 h/day indicating thermal stability of the film

  19. Improvement of thermal stability of nano-granular TMR films by using a Mg-Al-O insulator matrix

    Science.gov (United States)

    Kanie, S.; Koyama, S.

    2018-05-01

    A new metal-insulator nano-granular tunneling magnetoresistance (TMR) film made of (Fe-Co)-(Mg-Al-O) has been investigated. It is confirmed that the film has granular structure in which crystal Fe-Co granules are surrounded by an amorphous Mg-Al-O matrix. A large MR ratio of 11.8 % at room temperature is observed for a 42 vol.%(Fe0.6Co0.4)-(Mg-Al-O) film annealed at 395 °C. The electrical resistivity increases rapidly by annealing at above the changing point (500 °C). The changing point is about 300 °C higher than that of conventional (Fe-Co)-(Mg-F) nano-granular TMR films. The 42 vol.%(Fe0.6Co0.4)-(Mg-Al-O) film also exhibits less degradation in the MR ratio at high annealing temperatures such as 600 °C. These results suggest the (Fe-Co)-(Mg-Al-O) film is superior to the (Fe-Co)-(Mg-F) film in thermal stability.

  20. Modification of physicochemical and thermal properties of starch films by incorporation of TiO2 nanoparticles.

    Science.gov (United States)

    Oleyaei, Seyed Amir; Zahedi, Younes; Ghanbarzadeh, Babak; Moayedi, Ali Akbar

    2016-08-01

    In this research, potato starch and TiO2 nanoparticles (0.5, 1 and 2wt%) films were developed. Influences of different concentrations of TiO2 on the functional properties of nanocomposite films (water-related properties, mechanical characteristics, and UV transmittance) were investigated. XRD, FTIR, and DSC analyses were used to characterize the morphology and thermal properties of the films. The results revealed that TiO2 nanoparticles dramatically decreased the values of water-related properties (water vapor permeability: 11-34%; water solubility: 1.88-9.26%; moisture uptake: 2.15-11.18%). Incorporation of TiO2 led to a slight increment of contact angle and tensile strength, and a decrease in elongation at break of the films. TiO2 successfully blocked more than 90% of UV light, while opacity and white index of the films were enhanced. Glass transition temperature and melting point of the films were positively affected by the addition of TiO2 nanoparticles. The result of XRD study exhibited that due to a limited agglomeration of TiO2 nanoparticles, the mean crystal size of TiO2 increased. Formation of new hydrogen bonds between the hydroxyl groups of starch and nanoparticles was confirmed by FTIR spectroscopy. In conclusion, TiO2 nanoparticles improved the functional properties of potato starch film and extended the potential for food packaging applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Ellipsometry and XPS comparative studies of thermal and plasma enhanced atomic layer deposited Al2O3-films

    Directory of Open Access Journals (Sweden)

    Jörg Haeberle

    2013-11-01

    Full Text Available We report on results on the preparation of thin (2O3 films on silicon substrates using thermal atomic layer deposition (T-ALD and plasma enhanced atomic layer deposition (PE-ALD in the SENTECH SI ALD LL system. The T-ALD Al2O3 layers were deposited at 200 °C, for the PE-ALD films we varied the substrate temperature range between room temperature (rt and 200 °C. We show data from spectroscopic ellipsometry (thickness, refractive index, growth rate over 4” wafers and correlate them to X-ray photoelectron spectroscopy (XPS results. The 200 °C T-ALD and PE-ALD processes yield films with similar refractive indices and with oxygen to aluminum elemental ratios very close to the stoichiometric value of 1.5. However, in both also fragments of the precursor are integrated into the film. The PE-ALD films show an increased growth rate and lower carbon contaminations. Reducing the deposition temperature down to rt leads to a higher content of carbon and CH-species. We also find a decrease of the refractive index and of the oxygen to aluminum elemental ratio as well as an increase of the growth rate whereas the homogeneity of the film growth is not influenced significantly. Initial state energy shifts in all PE-ALD samples are observed which we attribute to a net negative charge within the films.

  2. Conductivity, work function, and environmental stability of PEDOT:PSS thin films treated with sorbitol

    NARCIS (Netherlands)

    Nardes, A.M.; Kemerink, M.; Kok, de M.M.; Vinken, E.; Maturova, K.; Janssen, R.A.J.

    2008-01-01

    The electrical properties of poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) thin films deposited from aqueous dispersion using different concentrations of sorbitol have been studied in detail. Although it is well known that sorbitol enhances the conductivity of PEDOT:PSS thin

  3. Plasma-treated polystyrene film that enhances binding efficiency for sensitive and label-free protein biosensing

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Bihong [National Center for NanoScience and Technology, No. 11 Beiyitiao, Zhongguancun, Beijing 100190 (China); Li, Shaopeng [National Center for NanoScience and Technology, No. 11 Beiyitiao, Zhongguancun, Beijing 100190 (China); Department of Chemistry, Tsinghua University, Beijing 100084 (China); Song, Lusheng [National Center for NanoScience and Technology, No. 11 Beiyitiao, Zhongguancun, Beijing 100190 (China); Yang, Mo; Zhou, Wenfei; Tyagi, Deependra [National Center for NanoScience and Technology, No. 11 Beiyitiao, Zhongguancun, Beijing 100190 (China); University of Chinese Academy of Sciences, Yuquan Rd., 19(A), Beijing 100049 (China); Zhu, Jinsong, E-mail: jizhu88@gmail.com [National Center for NanoScience and Technology, No. 11 Beiyitiao, Zhongguancun, Beijing 100190 (China)

    2015-08-01

    Highlights: • A simple and robust plasma-treated ultrathin polystyrene film surface was developed for protein biosensing. • The surface was optimized by evaluating up to 120 types of fabrication parameters with high-throughput analytical methods. • The optimized surface showed a 620% improvement of the protein detection signal and 210% protein binding per immobilized protein ligand compared with a self-assembled monolayer surface. - Abstract: A plasma-treated ultrathin polystyrene (PS) film surface was explored as a simple, robust, and low-cost surface chemistry solution for protein biosensing applications. This surface could dramatically improve the binding efficiency of the protein–protein interactions, which is defined as the binding signal per immobilized ligand. The PS-modified protein biosensor was readily fabricated by spin coating and plasma treatment. Various parameters for fabrication, including the concentration of the PS solution, rate of spin coating, and duration of plasma treatment, were systematically optimized based on the improvement of fluorescence signal yielded by the microfluidic network-aided fluorescence immunoassay. The performance of the label-free protein detection on the optimized surfaces was further evaluated by surface plasmon resonance imaging (SPRi). PS surfaces with optimal fabrication parameters exhibited up to an 620% enhancement of the protein binding response and approximately 210% of the protein binding per immobilized protein ligand compared with a self-assembled monolayer (SAM) surface of 11-mercapto undecanoic acid (MUA). The relationship between the fabrication parameters used and changes to the surface chemistry and the morphological properties were characterized with atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). It was revealed that the morphological changes observed in the plasma-treated PS film were the dominant factor for the

  4. Thermal shock effect on Mechanical and Physical properties of pre-moisture treated GRE composite

    Science.gov (United States)

    Chakraverty, A. P.; Panda, A. B.; Mohanty, U. K.; Mishra, S. C.; Biswal, B. B.

    2018-03-01

    Many practical situations may be encountered under which a GFRP (Glass fibre reinforced polymer) composite, during its service life, is exposed to the severities of sudden temperature fluctuations. Moisture absorption of GRE (Glass fibre reinforced epoxy) composites followed by various gradients of temperature fluctuations may cause thermo- mechanical degradation. It is on this context, the hand layed GRE composite samples are exposed to up-thermal shock (-40°C to +50°C) and down-thermal shock (+50°C to -40°C) for various time interval after several periods of moisture (hydrothermal/hygrothermal) conditioning. The thermally shocked GRE specimens are put to 3-point bend test to divulge inter laminar shear strength (ILSS). Least ILSS values are recorded for the samples with maximum period of moisture treatments under with both up-thermal and down-thermal shock conditions. Lower glass transition temperature (Tg) values, as revealed through the low temperature DSC test, are exhibited at maximum durations of both up-thermal and down-thermal shock for the samples with higher periods of hygrothermal/hydrothermal treatments. SEM fractographs of representative GRE specimens after optimum period of moisture treatments and thermal shock show the various modes of failures.

  5. Preliminary laboratory investigation of thermally treated recycled concrete aggregate for general use in concrete

    NARCIS (Netherlands)

    Larbi, J.A.; Heijnen, W.M.M.; Brouwer, J.P.; Mulder, E.

    2000-01-01

    This paper deals with a preliminary laboratory study to assess the effectiveness of thermal treatment methods to improve the quality of recycled concrete aggregate. The samples used for the study consisted of sieved fractions of crushed concrete that were subjected to various thermal treatments at

  6. Synthesis of transparent ZnO/PMMA nanocomposite films through free-radical copolymerization of asymmetric zinc methacrylate acetate and in-situ thermal decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lin [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Li Fan, E-mail: lfan@ncu.edu.cn [Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Chen Yiwang, E-mail: ywchen@ncu.edu.cn [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Wang Xiaofeng [Institute of Polymers, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China)

    2011-08-15

    In this paper, a new and simple approach for in-situ preparation of transparent ZnO/poly(metyl methacrylate) (ZnO/PMMA) nanocomposite films was developed. Poly(methyl methacrylate)-co-poly(zinc methacrylate acetate) (PMMA-co-PZnMAAc) copolymer was synthesized via free-radical polymerization between methyl methacrylate (MMA) and zinc methacrylate acetate (ZnMAAc), where asymmetric ZnMAAc with only one terminal double bond (C=C) was applied to act as the precursor for ZnO nanocrystals and could avoid cross-link. Subsequently, transparent ZnO/PMMA nanocomposite films were obtained by in-situ thermal decomposition. Scanning electron microscope (SEM) image revealed that ZnO nanocrystals were homogeneously dispersed in PMMA matrix. With thermal decomposition time increasing, the absorption intensity in UV region and photoluminescence intensity of ZnO/PMMA nanocomposite films enhanced. However, the optical properties diminished when the thermal decomposition temperature increased. The TGA measurement displayed ZnO/PMMA nanocomposite films prepared by the in-situ synthesis method possessed better thermal stability compared with those prepared by the physical blending method and pristine PMMA films. - Highlights: > ZnO/PMMA hybrid films were prepared via free-radical polymerization and in-situ thermal decomposition. > ZnO NCs are homogeneously dispersed in the PMMA matrix and these films have good optical properties. > Thermal stability of these films is improved compared with those of physically blending ones.

  7. Synthesis of transparent ZnO/PMMA nanocomposite films through free-radical copolymerization of asymmetric zinc methacrylate acetate and in-situ thermal decomposition

    International Nuclear Information System (INIS)

    Zhang Lin; Li Fan; Chen Yiwang; Wang Xiaofeng

    2011-01-01

    In this paper, a new and simple approach for in-situ preparation of transparent ZnO/poly(metyl methacrylate) (ZnO/PMMA) nanocomposite films was developed. Poly(methyl methacrylate)-co-poly(zinc methacrylate acetate) (PMMA-co-PZnMAAc) copolymer was synthesized via free-radical polymerization between methyl methacrylate (MMA) and zinc methacrylate acetate (ZnMAAc), where asymmetric ZnMAAc with only one terminal double bond (C=C) was applied to act as the precursor for ZnO nanocrystals and could avoid cross-link. Subsequently, transparent ZnO/PMMA nanocomposite films were obtained by in-situ thermal decomposition. Scanning electron microscope (SEM) image revealed that ZnO nanocrystals were homogeneously dispersed in PMMA matrix. With thermal decomposition time increasing, the absorption intensity in UV region and photoluminescence intensity of ZnO/PMMA nanocomposite films enhanced. However, the optical properties diminished when the thermal decomposition temperature increased. The TGA measurement displayed ZnO/PMMA nanocomposite films prepared by the in-situ synthesis method possessed better thermal stability compared with those prepared by the physical blending method and pristine PMMA films. - Highlights: → ZnO/PMMA hybrid films were prepared via free-radical polymerization and in-situ thermal decomposition. → ZnO NCs are homogeneously dispersed in the PMMA matrix and these films have good optical properties. → Thermal stability of these films is improved compared with those of physically blending ones.

  8. MHD Flow and Heat Transfer Characteristics in a Casson Liquid Film Towards an Unsteady Stretching Sheet with Temperature-Dependent Thermal Conductivity

    Science.gov (United States)

    Mahmoud, Mostafa A. A.; Megahed, Ahmed M.

    2017-10-01

    Theoretical and numerical outcomes of the non-Newtonian Casson liquid thin film fluid flow owing to an unsteady stretching sheet which exposed to a magnetic field, Ohmic heating and slip velocity phenomena is reported here. The non-Newtonian thermal conductivity is imposed and treated as it vary with temperature. The nonlinear partial differential equations governing the non-Newtonian Casson thin film fluid are simplified into a group of highly nonlinear ordinary differential equations by using an adequate dimensionless transformations. With this in mind, the numerical solutions for the ordinary conservation equations are found using an accurate shooting iteration technique together with the Runge-Kutta algorithm. The lineaments of the thin film flow and the heat transfer characteristics for the pertinent parameters are discussed through graphs. The results obtained here detect many concern for the local Nusselt number and the local skin-friction coefficient in which they may be beneficial for the material processing industries. Furthermore, in some special conditions, the present problem has an excellent agreement with previously published work.

  9. X-ray photoelectron spectroscopy study of the passive films formed on thermally sprayed and wrought Inconel 625

    Energy Technology Data Exchange (ETDEWEB)

    Bakare, M.S. [Materials, Mechanics and Structures Research Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Voisey, K.T., E-mail: Katy.voisey@nottingham.ac.uk [Materials, Mechanics and Structures Research Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Roe, M.J.; McCartney, D.G. [Materials, Mechanics and Structures Research Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom)

    2010-11-15

    There is a well known performance gap in corrosion resistance between thermally sprayed corrosion resistant coatings and the equivalent bulk materials. Interconnected porosity has an important and well known effect, however there are additional relevant microstructural effects. Previous work has shown that a compositional difference exists between the regions of resolidified and non-melted material that exist in the as-sprayed coatings. The resolidified regions are depleted in oxide forming elements due to formation of oxides during coating deposition. Formation of galvanic cells between these different regions is believed to decrease the corrosion resistance of the coating. In order to increase understanding of the details of this effect, this work uses X-ray photoelectron spectroscopy (XPS) to study the passive films formed on thermally sprayed coatings (HVOF) and bulk Inconel 625, a commercially available corrosion resistant Ni-Cr-Mo-Nb alloy. Passive films produced by potentiodynamic scanning to 400 mV in 0.5 M sulphuric acid were compared with air-formed films. The poorer corrosion performance of the thermally sprayed coatings was attributed to Ni(OH){sub 2}, which forms a loose, non-adherent and therefore non-protective film. The good corrosion resistance of wrought Inconel 625 is due to formation of Cr, Mo and Nb oxides.

  10. Enhanced mechanical, thermal and antimicrobial properties of poly(vinyl alcohol)/graphene oxide/starch/silver nanocomposites films.

    Science.gov (United States)

    Usman, Adil; Hussain, Zakir; Riaz, Asim; Khan, Ahmad Nawaz

    2016-11-20

    In the present work, synthesis of poly(vinyl alcohol)/graphene oxide/starch/silver (PVA/GO/Starch/Ag) nanocomposites films is reported. Such films have been characterized and investigated for their mechanical, thermal and antimicrobial properties. The exfoliation of GO in the PVA matrix occurs owing to the non-covalent interactions of the polymer chains of PVA and hydrophilic surface of the GO layers. Presence of GO in PVA and PVA/starch blends were found to enhance the tensile strength of the nanocomposites system. It was found that the thermal stability of PVA as well as PVA/starch blend systems increased by the incorporation of GO where strong physical bonding between GO layers and PVA/starch blends is assumed to cause thermal barrier effects. Antimicrobial properties of the prepared films were investigated against Escherichia coli and Staphylococcus aureus. Our results show enhanced antimicrobial properties of the prepared films where PVA-GO, PVA-Ag, PVA-GO-Ag and PVA-GO-Ag-Starch showed antimicrobial activity in ascending order. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Simultaneous thermal stability and phase change speed improvement of Sn15Sb85 thin film through erbium doping

    Science.gov (United States)

    Zou, Hua; Zhu, Xiaoqin; Hu, Yifeng; Sui, Yongxing; Sun, Yuemei; Zhang, Jianhao; Zheng, Long; Song, Zhitang

    2016-12-01

    In general, there is a trade off between the phase change speed and thermal stability in chalcogenide phase change materials, which leads to sacrifice the one in order to ensure the other. For improving the performance, doping is a widely applied technological process. Here, we fabricated Er doped Sn15Sb85 thin films by magnetron sputtering. Compared with the pure Sn15Sb85, we show that Er doped Sn15Sb85 thin films exhibit simultaneous improvement over the thermal stability and the phase change speed. Thus, our results suggest that Er doping provides the opportunity to solve the contradiction. The main reason for improvement of both thermal stability and crystallization speed is due to the existence of Er-Sb and Er-Sn bonds in Er doped Sn15Sb85 films. Hence, Er doped Sn15Sb85 thin films are promising candidates for the phase change memory application, and this method could be extended to other lanthanide-doped phase change materials.

  12. Influence of operating parameters on surface properties of RF glow discharge oxygen plasma treated TiO{sub 2}/PET film for biomedical application

    Energy Technology Data Exchange (ETDEWEB)

    Pandiyaraj, K. Navaneetha, E-mail: dr.knpr@gmail.com [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L and T by pass, Chinniyam Palayam (post), Coimbatore 641062 (India); Deshmukh, R.R. [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai 400 019 (India); Mahendiran, R. [Surface Engineering Laboratory, Department of Physics, Sri Shakthi Institute of Engineering and Technology, L and T by pass, Chinniyam Palayam (post), Coimbatore 641062 (India); Su, Pi-G [Department of Chemistry, Chinese Culture University, Taipei 111, Taiwan (China); Yassitepe, Emre; Shah, Ismat [Department of Physics and Astronomy, Department of Materials Science and Engineering, University of Delaware, 208 Dupont Hall, Newark (United States); Perni, Stefano [School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff (United Kingdom); Prokopovich, Polina [School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff (United Kingdom); Institute of Medical Engineering and Medical Physics, School of Engineering, Cardiff University (United Kingdom); Nadagouda, Mallikarjuna N., E-mail: Nadagouda.Mallikarjuna@epamail.epa.gov [The U.S. Environmental Protection Agency, ORD, NRMRL, WSWRD, 26W. Martin Luther King Drive, Cincinnati, OH 45268 (United States)

    2014-03-01

    In this paper, a thin transparent titania (TiO{sub 2}) film was coated on the surface of flexible poly(ethylene terephthalate) (PET) film using the sol–gel method. The surface properties of the obtained TiO{sub 2}/PET film were further improved by RF glow discharge oxygen plasma as a function of exposure time and discharge power. The changes in hydrophilicity of TiO{sub 2}/PET films were analyzed by contact angle measurements and surface energy. The influence of plasma on the surface of the TiO{sub 2}/PET films was analyzed by atomic force microscopy (AFM) as well as the change in chemical state and composition that were investigated by X-ray photo electron spectroscopy (XPS). The cytotoxicity of the TiO{sub 2}/PET films was analyzed using human osteoblast cells and the bacterial eradication behaviors of TiO{sub 2}/PET films were also evaluated against Staphylococcus bacteria. It was found that the surface roughness and incorporation of oxygen containing polar functional groups of the plasma treated TiO{sub 2}/PET films increased substantially as compared to the untreated one. Moreover the increased concentration of Ti{sup 3+} on the surface of plasma treated TiO{sub 2}/PET films was due to the transformation of chemical states (Ti{sup 4+} → Ti{sup 3+}). These morphological and chemical changes are responsible for enhanced hydrophilicity of the TiO{sub 2}/PET films. Furthermore, the plasma treated TiO{sub 2}/PET film exhibited no citotoxicity against osteoblast cells and antibacterial activity against Staphylococcus bacteria which can find application in manufacturing of biomedical devices. - Graphical abstract: Mechanism of plasma treatment on the surface of TiO{sub 2}/PET films. - Highlights: • Investigated the surface properties of TiO{sub 2}/PET films modified by O{sub 2} plasma • Studied the effect of operating parameters on surface properties of TiO{sub 2}/PET films • Mechanism of the plasma treatment on TiO{sub 2}/PET was clearly investigated.

  13. X-ray diffraction study of thermal stress relaxation in ZnO films deposited by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Conchon, F. [Institut P' , Universite de Poitiers-Ensma-UPR CNRS 3346, 86962 Futuroscope (France); Renault, P.O., E-mail: pierre.olivier.renault@univ-poitiers.f [Institut P' , Universite de Poitiers-Ensma-UPR CNRS 3346, 86962 Futuroscope (France); Le Bourhis, E.; Krauss, C.; Goudeau, P. [Institut P' , Universite de Poitiers-Ensma-UPR CNRS 3346, 86962 Futuroscope (France); Barthel, E.; Grachev, S. Yu.; Sondergard, E. [Lab. Surface du Verre et Interfaces (SVI), UMR 125, 93303 Aubervilliers (France); Rondeau, V.; Gy, R. [Lab. Recherche de Saint-Gobain (SGR), 93303 Aubervilliers (France); Lazzari, R.; Jupille, J. [Institut des Nanosciences de Paris (INSP), UMR 7588, 75015 Paris (France); Brun, N. [Lab. Physique des Solides (LPS), UMR 8502, 91405 Orsay (France)

    2010-12-30

    X-ray diffraction stress analyses have been performed on two different thin films deposited onto silicon substrate: ZnO and ZnO encapsulated into Si{sub 3}N{sub 4} layers. We showed that both as-deposited ZnO films are in a high compressive stress state. In situ X-ray diffraction measurements inside a furnace revealed a relaxation of the as-grown stresses at temperatures which vary with the atmosphere in the furnace and change with Si{sub 3}N{sub 4} encapsulation. The observations show that Si{sub 3}N{sub 4} films lying on both sides of the ZnO film play an important role in the mechanisms responsible for the stress relaxation during heat treatment. The different temperatures observed for relaxation in ambient and argon atmospheres suggest that the thermally activated stress relaxation may be attributed to a variation of the stoichiometry of the ZnO films. The present observations pave the way to fine tuning of the residual stresses through thermal treatment parameters.

  14. Selective etching characteristics of the AgInSbTe phase-change film in laser thermal lithography

    International Nuclear Information System (INIS)

    Li, Hao; Geng, Yongyou; Wu, Yiqun

    2012-01-01

    In the current work, the etching selectivity of the AgInSbTe phase-change film in laser thermal lithography is reported for the first time. Film phase change induced by laser irradiation and etching selectivity to crystalline and amorphous states in different etchants, including hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, sodium hydroxide, sodium sulfide, ammonium sulfide and ammonium hydroxide, are investigated. The results indicated that ammonium sulfide solvent (2.5 mol/L) had excellent etching selectivity to crystalline and amorphous states of the AgInSbTe film, and the etching characteristics were strongly influenced by the laser power density and laser irradiation time. The etching rate of the crystalline state of the AgInSbTe film was 40.4 nm/min, 20 times higher than that of the amorphous state under optimized irradiation conditions (power density: 6.63 mW/μm 2 and irradiation time: 330 ns), with ammonium sulfide solvent (2.5 mol/L) as etchant. The step profile produced in the selective etching was clear, and smooth surfaces remained both on the step-up and step-down with a roughness of less than 4 nm (10 x 10 μm). The excellent performance of the AgInSbTe phase-change film in selective etching is significant for fabrication of nanostructures with super-resolution in laser thermal lithography. (orig.)

  15. Ion-beam mixing and thermal annealing of Al--Nb and Al--Ta thin films

    International Nuclear Information System (INIS)

    Rai, A.K.; Bhattacharya, R.S.; Mendiratta, M.G.; Subramanian, P.R.; Dimiduk, D.M.

    1988-01-01

    Ion-beam mixing and thermal annealing of thin, alternating layers of Al and Nb, as well as Al and Ta, were investigated by selected area diffraction and Rutherford backscattering. The individual layer thicknesses were adjusted to obtain the overall compositions as Al 3 Nb and Al 3 Ta. The films were ion mixed with 1 MeV Au + ions at a dose of 1 x 10 16 ions cm/sup -2/ . Uniform mixing and amorphization were achieved for both Al--Nb and Al--Ta systems. Equilibrium crystalline Al 3 Nb and Al 3 Ta phases were formed after annealing of ion mixed amorphous films at 400 0 C for 6 h. Unmixed films, however, remained unreacted at 400 0 C for 1 h. Partial reaction was observed in the unmixed film of Al--Nb at 400 0 C for 6 h. After annealing at 500 0 C for 1 h, a complete reaction and formation of Al 3 Nb and Al 3 Ta phases in the respective films were observed. The influence of thermodynamics on the phase formation by ion mixing and thermal annealing is discussed

  16. Improvement of the characteristics of chemical bath deposition-cadmium sulfide films deposited on an O{sub 2} plasma-treated polyethylene terephthalate substrate

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Donggun [Department of Electronic Engineering, Korea National University of Transportation, Chungju-si, Chungcheongbuk-do 380-702 (Korea, Republic of); Lee, Jaehyeong [School of Electronic and Electrical Engineering, Sungkyunkwan University 300, Cheoncheon-dong, Jangan-gu, Sunwon, Kyeonggi-do, 440-746 (Korea, Republic of); Song, Woochang, E-mail: wcsong@kangwon.ac.kr [Department of Electrical Engineering, Kangwon National University, Samcheok-si, Gangwon-do 245-711 (Korea, Republic of)

    2013-11-01

    We prepared cadmium sulfide (CdS) films on a polyethylene terephthalate (PET) substrate by a chemical bath deposition (CBD) technique. To improve the adhesion between the CdS film and the PET substrate, the substrate was pre-treated with an O{sub 2} plasma by an inductively coupled plasma. The surface characterizations of the pre-treated PET substrate were analyzed by a contact angle measurement and atomic force microscopy. The results showed that that O{sub 2} plasma-treated PET films had more hydrophilic surface. The hydrophilic property of the substrate is one of the important factors when a film is prepared by CBD. The structural and the optical properties of the CdS films, deposited on PET substrates, were analyzed by using a scanning electron microscope, X-ray diffraction and a UV–visible spectrophotometer. The CdS films were formed on a compact and granular structure. The optical transmittance was also improved. Therefore, the O{sub 2} plasma treatment of a PET surface is an effective method of preparing CdS films deposited on substrates by CBD. - Highlights: • Chemical bath deposition of CdS film for flexible solar cells • O{sub 2} plasma treatment improved adhesion between the CdS and polymer substrate • Identification of best fabrication condition of CdS window layers for flexible solar cells.

  17. Flexible polyimide films hybrid with functionalized boron nitride and graphene oxide simultaneously to improve thermal conduction and dimensional stability.

    Science.gov (United States)

    Tsai, Mei-Hui; Tseng, I-Hsiang; Chiang, Jen-Chi; Li, Jheng-Jia

    2014-06-11

    Coupling agent-functionalized boron nitride (f-BN) and glycidyl methacrylate-grafted graphene (g-TrG) are simultaneously blended with polyimide (PI) to fabricate a flexible, electrically insulating and thermally conductive PI composite film. The silk-like g-TrG successfully fills in the gap between PI and f-BN to complete the thermal conduction network. In addition, the strong interaction between surface functional groups on f-BN and g-TrG contributes to the effective phonon transfer in the PI matrix. The thermal conductivity (TC) of the PI/f-BN composite films containing additional 1 wt % of g-TrG is at least doubled to the value of PI/f-BN and as high as 16 times to that of the pure PI. The hybrid film PI/f-BN-50/g-TrG-1 exhibits excellent flexibility, sufficient insulating property, the highest TC of 2.11 W/mK, and ultralow coefficient of thermal expansion of 11 ppm/K, which are perfect conditions for future flexible substrate materials requiring efficient heat dissipation.

  18. Enhanced coercivity thermal stability realized in Nd–Fe–B thin films diffusion-processed by Nd–Co alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Hui; Fu, Yanqing [Key laboratory of electromagnetic processing of materials (EPM), Ministry of Education, Northeastern University, Shenyang 110819 (China); Department of Physics and Chemistry of Materials, School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Li, Guojian; Liu, Tie [Key laboratory of electromagnetic processing of materials (EPM), Ministry of Education, Northeastern University, Shenyang 110819 (China); Cui, Weibin, E-mail: cuiweibin@epm.neu.edu.cn [Key laboratory of electromagnetic processing of materials (EPM), Ministry of Education, Northeastern University, Shenyang 110819 (China); Department of Physics and Chemistry of Materials, School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Liu, Wei; Zhang, Zhidong [Shenyang National Laboratory for Materials Science, Institute of Metal Research (IMR), Chinese Academy of Sciences (CAS), Shenyang 110016 (China); Wang, Qiang, E-mail: wangq@mail.neu.edu.cn [Key laboratory of electromagnetic processing of materials (EPM), Ministry of Education, Northeastern University, Shenyang 110819 (China)

    2017-03-15

    A proposed Nd{sub 2}Fe{sub 14}B-core/Nd{sub 2}(Fe, Co){sub 14}B-shell microstructure was realized by diffusion-processing textured Nd{sub 14}Fe{sub 77}B{sub 9} single-layer film with Nd{sub 100−x}Co{sub x} (x=10, 20 and 40) alloys to improve the coercivity thermal stability. The ambient coercivity was increased from around 1 T in single-layer film to nearly 2 T in diffusion-processed films, which was due to the Nd-rich grain boundaries as seen from transmission electron microscopy (TEM) images. The coercivity thermal stability was improved by the core/shell microstructure because Nd-rich grain boundaries provided the high ambient coercivity and Co-rich shell provided the improved coercivity stability. - Highlights: • Core–shell microstructure proposed for enhancing the coercivity thermal stability. • Coercivity enhanced to nearly 2 T by diffusion-processing with Nd–Co alloy. • Good squareness and highly textured microstructure obtained. • Nd-rich phases observed by TEM after diffusion process. • Coercivity thermal stability improved with minor Co addition in grain boundary regions.

  19. Metamorphosis of strain/stress on optical band gap energy of ZAO thin films via manipulation of thermal annealing process

    International Nuclear Information System (INIS)

    Malek, M.F.; Mamat, M.H.; Musa, M.Z.; Soga, T.; Rahman, S.A.; Alrokayan, Salman A.H.; Khan, Haseeb A.; Rusop, M.

    2015-01-01

    We report on the growth of Al-doped ZnO (ZAO) thin films prepared by the sol–gel technique associated with dip-coating onto Corning 7740 glass substrates. The influence of varying thermal annealing (T a ) temperature on crystallisation behaviour, optical and electrical properties of ZAO films has been systematically investigated. All films are polycrystalline with a hexagonal wurtzite structure with a preferential orientation according to the direction 〈0 0 2〉. The metamorphosis of strain/stress effects in ZAO thin films has been investigated using X-ray diffraction. The as growth films have a large compressive stress of 0.55 GPa, which relaxed to 0.25 GPa as the T a was increased to 500 °C. Optical parameters such as optical transmittance, absorption coefficient, refractive index and optical band gap energy have been studied and discussed with respect to T a . All films exhibit a transmittance above 80–90% along the visible–NIR range up to 1500 nm and a sharp absorption onset below 400 nm corresponding to the fundamental absorption edge of ZnO. Experimental results show that the tensile stress in the films reveals an incline pattern with the optical band gap energy, while the compressive stress shows opposite relation. - Highlights: • Minimum stress of highly c-axis oriented ZAO was grown at suitable T a temperature. • The ZAO crystal orientation was influenced by strain/stress of the film. • Minimum stress/strain of ZAO film leads to lower defects. • Bandgap and defects were closely intertwined with strain/stress. • We report additional optical and electrical properties based on T a temperature

  20. Metamorphosis of strain/stress on optical band gap energy of ZAO thin films via manipulation of thermal annealing process