WorldWideScience

Sample records for continuous metal films

  1. Formation of continuous metallic film on quartz studied by noncontact resonant ultrasound spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, N., E-mail: nobutomo@me.es.osaka-u.ac.jp; Yoshimura, N.; Ogi, H.; Hirao, M. [Osaka University, Graduate School of Engineering Science, Toyonaka, Osaka 560-8531 (Japan)

    2015-08-28

    Dynamics of continuous film formation of metallic films on quartz substrates is studied using an electrodeless resonance method. Bare quartz is used as a substrate, and a metallic film is deposited on it. We use antenna transmission technique to measure the evolution of resonance frequencies and internal friction of the substrate during and after deposition, and the morphological transition between discontinuous islands and a continuous film is detected. By comparison with atomic force microscopy images, we confirm that the frequency drop and the internal-friction peak that appear during deposition indicate this transition. We also find that Pt film shows unexpected morphology change after deposition.

  2. Effect of scanning speed on continuous wave laser scribing of metal thin films: theory and experiment

    Science.gov (United States)

    Shahbazi, AmirHossein; Koohian, Ata; Madanipour, Khosro

    2017-01-01

    In this paper continuous wave laser scribing of the metal thin films have been investigated theoretically and experimentally. A formulation is presented based on parameters like beam power, spot size, scanning speed and fluence thresholds. The role of speed on the transient temperature and tracks width is studied numerically. By using two frameworks of pulsed laser ablation of thin films and laser printing on paper, the relation between ablation width and scanning speed has been derived. Furthermore, various speeds of the focused 450 nm continuous laser diode with an elliptical beam spot applied to a 290 nm copper thin film coated on glass, experimentally. The beam power was 150 mW after spatial filtering. By fitting the theoretical formulation to the experimental data, the threshold fluence and energy were obtained to be 13.2 J mm-2 and 414~μ J respectively. An anticipated theoretical parameter named equilibrium~border was verified experimentally. It shows that in the scribing of the 290 nm copper thin film, at a distance where the intensity reaches about 1/e of its maximum value, the absorbed fluence on the surface is equal to zero. Therefore the application of continuous laser in metal thin film ablation has different mechanism from pulsed laser drilling and beam scanning in printers.

  3. Near-unity transparency of a continuous metal film via cooperative effects of double plasmonic arrays.

    Science.gov (United States)

    Liu, Zheng-qi; Liu, Gui-qiang; Zhou, Hai-qing; Liu, Xiao-shan; Huang, Kuan; Chen, Yuan-hao; Fu, Guo-lan

    2013-04-19

    Metal structures with high optical transparency and conductivity are of great importance for practical applications in optoelectronic devices. Here we investigate the transparency response of a continuous metal film sandwiched by double plasmonic nanoparticle arrays. The upper nanoparticle array shows efficient light trapping of the incident field, acting as a light input coupler, and the lower nanoparticle array shows a light release gate opening at the other side, acting as the light output coupler. The strong near-field light-matter interactions of the nano-scale separated plasmonic nanoparticles, the excitation of surface plasmon waves of the metal film, and their cooperative coupling effects result in broadband scattering cancellation and near-unity transparency (up to 96%) in the optical regime. The transparency response in such a structure can be efficiently modified by varying the gap distance of adjacent nanoparticles, dielectric environments, and the distance between the plasmonic array and the metal film. This motif may provide a new alternative approach to obtain transparent and highly conducting metal structures with potential applications in transparent conductors, plasmonic filters, and highly integrated light input and output components.

  4. Multispectral optical enhanced transmission of a continuous metal film coated with a plasmonic core-shell nanoparticle array

    Science.gov (United States)

    Liu, Gui-qiang; Hu, Ying; Liu, Zheng-qi; Cai, Zheng-jie; Zhang, Xiang-nan; Chen, Yuan-hao; Huang, Kuan

    2014-04-01

    We propose and show multispectral optical enhanced transmission in the visible and near-infrared region in a continuous metal film coated with a two-dimensional (2D) hexagonal non-close-packed plasmonic array. The plasmonic array consists of metal/dielectric multilayer core-shell nanoparticles. The excitation of near-field plasmon resonance coupling between adjacent core-shell nanoparticles, plasmon resonance coupling between adjacent metal layers in the nanoparticle, and surface plasmon (SP) waves on the metal film are mainly responsible for the multispectral optical enhanced transmission behavior. The multispectral optical enhanced transmission response could be highly modified in the wavelength range, transparent bandwidth and transmission intensity by varying the geometry parameters including the gap distance between adjacent plasmonic nanoparticles, the size of metal core and the thickness of dielectric layer between the metal layers. In addition, the number of optical enhanced transmission bands increases with the number of metal layers in the plasmonic nanoparticle. The proposed structure shows many merits such as the deep sub-wavelength size, multispectral optical enhanced transmission bands as well as fully retained electric and mechanical properties of the natural metal. These merits may provide promising applications for highly integrated optoelectronic devices including plasmonic filters, nanoscale multiplexers, and nonlinear optics.

  5. Robust multispectral transparency in continuous metal film structures via multiple near-field plasmon coupling by a finite-difference time-domain method.

    Science.gov (United States)

    Liu, Gui-qiang; Hu, Ying; Liu, Zheng-qi; Chen, Yuan-hao; Cai, Zheng-jie; Zhang, Xiang-nan; Huang, Kuan

    2014-03-07

    We propose a robust multispectral transparent plasmonic structure and calculate its transparency response by using the three-dimensional finite-difference time-domain (FDTD) method. The proposed structure is composed of a continuous ultrathin metal film sandwiched by double two-dimensional (2D) hexagonal non-close-packed metal-dielectric multilayer core-shell nanoparticle arrays. The top and bottom plasmonic arrays in such a structure, respectively, act as the light input and output couplers to carry out the efficient trapping and release of light. Near-perfect multispectral optical transparency in the visible and near-infrared regions is achieved theoretically. The calculated electric field distribution patterns show that the near-perfect multispectral optical transparency mainly originates from the excitation and hybridization of shell and core plasmon modes, strong near-field coupling of dipole plasmon modes between adjacent nanoparticles as well as the excitation of surface plasmon waves of the metal film. The robust transparency bands can be efficiently tuned in a large range by varying the structural parameters and the surrounding dielectric environment. The proposed structure also shows additional merits such as a deep sub-wavelength size and fully retained electrical and mechanical properties of the natural metal. These features might provide promising applications in highly integrated optoelectronic devices including plasmonic filters, nanoscale multiplexers, and non-linear optics.

  6. When are thin films of metals metallic?

    Science.gov (United States)

    Plummer, E. W.; Dowben, P. A.

    1993-04-01

    There is an increasing body of experimental information suggesting that very thin films of materials, normally considered to be metals, exhibit behavior characteristic of a nonmetal. In almost all cases, there is a nonmetal-to-metal transition as a function of film density or thickness, frequently accompanied by a structural transition. Amazingly, this behavior seems to occur for metal films on metal substrates, as well as for metals on semiconductors. The identification of this phenomena and the subsequent explanation has been slow in developing, due to the inability to directly measure the conductivity of a submonolayer film. This paper will discuss the evidence accumulated from variety of spectroscopic experimental techniques for three systems: a Mott-Hubbard transition, a Peierls-like distortion, and a Wilson transition.

  7. Continuous metal plasmonic frequency selective surfaces.

    Science.gov (United States)

    Zhang, Jianfa; Ou, Jun-Yu; Papasimakis, Nikitas; Chen, Yifang; Macdonald, Kevin F; Zheludev, Nikolay I

    2011-11-07

    In the microwave part of the spectrum, where losses are minimal, metal films regularly patterned (perforated) on the sub-wavelength scale achieve spectral selectivity by balancing the transmission and reflection characteristics of the surface. Here we show for optical frequencies, where joule losses are important, that periodic structuring of a metal film without violation of continuity (i.e. without perforation) is sufficient to achieve substantial modification of reflectivity. By engineering the geometry of the structure imposed on a surface one can dramatically change the perceived color of the metal without employing any form of chemical modification, thin-film coating or diffraction effects. This novel frequency selective effect is underpinned by plasmonic Joule losses in the constituent elements of the patterns (dubbed 'intaglio' and 'bas relief' metamaterials to distinguish indented and raised structures respectively) and is specific to the optical part of the spectrum. It has the advantage of maintaining the integrity of metal surfaces and is well suited to high-throughput fabrication via techniques such as nano-imprint.

  8. Thin-film metal hydrides.

    Science.gov (United States)

    Remhof, Arndt; Borgschulte, Andreas

    2008-12-01

    The goal of the medieval alchemist, the chemical transformation of common metals into nobel metals, will forever be a dream. However, key characteristics of metals, such as their electronic band structure and, consequently, their electric, magnetic and optical properties, can be tailored by controlled hydrogen doping. Due to their morphology and well-defined geometry with flat, coplanar surfaces/interfaces, novel phenomena may be observed in thin films. Prominent examples are the eye-catching hydrogen switchable mirror effect, the visualization of solid-state diffusion and the formation of complex surface morphologies. Thin films do not suffer as much from embrittlement and/or decrepitation as bulk materials, allowing the study of cyclic absorption and desorption. Therefore, thin-metal hydride films are used as model systems to study metal-insulator transitions, for high throughput combinatorial research or they may be used as indicator layers to study hydrogen diffusion. They can be found in technological applications as hydrogen sensors, in electrochromic and thermochromic devices. In this review, we discuss the effect of hydrogen loading of thin niobium and yttrium films as archetypical examples of a transition metal and a rare earth metal, respectively. Our focus thereby lies on the hydrogen induced changes of the electronic structure and the morphology of the thin films, their optical properties, the visualization and the control of hydrogen diffusion and on the study of surface phenomena and catalysis.

  9. Stress in hard metal films

    NARCIS (Netherlands)

    Janssen, G.C.A.M.; Kamminga, J.D.

    2004-01-01

    In the absence of thermal stress, tensile stress in hard metal films is caused by grain boundary shrinkage and compressive stress is caused by ion peening. It is shown that the two contributions are additive. Moreover tensile stress generated at the grain boundaries does not relax by ion bombardment

  10. High-Performance Flexible Thin-Film Transistors Based on Single-Crystal-like Silicon Epitaxially Grown on Metal Tape by Roll-to-Roll Continuous Deposition Process.

    Science.gov (United States)

    Gao, Ying; Asadirad, Mojtaba; Yao, Yao; Dutta, Pavel; Galstyan, Eduard; Shervin, Shahab; Lee, Keon-Hwa; Pouladi, Sara; Sun, Sicong; Li, Yongkuan; Rathi, Monika; Ryou, Jae-Hyun; Selvamanickam, Venkat

    2016-11-02

    Single-crystal-like silicon (Si) thin films on bendable and scalable substrates via direct deposition are a promising material platform for high-performance and cost-effective devices of flexible electronics. However, due to the thick and unintentionally highly doped semiconductor layer, the operation of transistors has been hampered. We report the first demonstration of high-performance flexible thin-film transistors (TFTs) using single-crystal-like Si thin films with a field-effect mobility of ∼200 cm(2)/V·s and saturation current, I/lW > 50 μA/μm, which are orders-of-magnitude higher than the device characteristics of conventional flexible TFTs. The Si thin films with a (001) plane grown on a metal tape by a "seed and epitaxy" technique show nearly single-crystalline properties characterized by X-ray diffraction, Raman spectroscopy, reflection high-energy electron diffraction, and transmission electron microscopy. The realization of flexible and high-performance Si TFTs can establish a new pathway for extended applications of flexible electronics such as amplification and digital circuits, more than currently dominant display switches.

  11. Metal-Filme

    OpenAIRE

    Fendler, Julia

    2010-01-01

    Heavy Metal hat seinen Ursprung im Hard- und Bluesrock der 1960er und 1970er Jahre. Seine musikalischen Vorgänger sind Bands wie Led Zeppelin, Deep Purple und Iron Butterfly. Der Begriff taucht in der Musik erstmals 1968 auf, als Iron Butterfly ihrem Debütalbum den Titel 'Heavy' gaben und Steppenwolf in ihrem Song 'Born to be wild' über "heavy metal thunder" sangen. Die Entstehung des Ausdrucks ist jedoch unklar, sie wird unter anderem Jimi Hendrix zugeordnet, aber auch als Ausdruck für eine ...

  12. Process for fabrication of metal oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Tracy, C.E.; Benson, D.; Svensson, S.

    1990-07-17

    This invention is comprised of a method of fabricating metal oxide films from a plurality of reactants by inducing a reaction by plasma deposition among the reactants. The plasma reaction is effective for consolidating the reactants and producing thin films of metal oxides, e.g. electro-optically active transition metal oxides, at a high deposition rate. The presence of hydrogen during the plasma reaction enhances the deposition rate of the metal oxide. Various types of metal oxide films can be produced.

  13. Flexible amorphous metal films with high stability

    Science.gov (United States)

    Liu, M.; Cao, C. R.; Lu, Y. M.; Wang, W. H.; Bai, H. Y.

    2017-01-01

    We report the formation of amorphous Cu50Zr50 films with a large-area of more than 100 cm2. The films were fabricated by ion beam assisted deposition with a slow deposition rate at moderate temperature. The amorphous films have markedly enhanced thermal stability, excellent flexibility, and high reflectivity with atomic level smoothness. The multifunctional properties of the amorphous films are favorites in the promising applications of smart skin or wearable devices. The method of preparing highly stable amorphous metal films by tuning the deposition rate instead of deposition temperature could pave a way for exploring amorphous metal films with unique properties.

  14. Flexible Thin Metal Film Thermal Sensing System

    Science.gov (United States)

    Thomsen, Donald Laurence (Inventor)

    2012-01-01

    A flexible thin metal film thermal sensing system is provided. A thermally-conductive film made from a thermally-insulating material is doped with thermally-conductive material. At least one layer of electrically-conductive metal is deposited directly onto a surface of the thermally-conductive film. One or more devices are coupled to the layer(s) to measure an electrical characteristic associated therewith as an indication of temperature.

  15. Reliable and well-controlled synthesis of noble metal nanoparticles by continuous wave laser ablation in different liquids for deposition of thin films with variable optical properties

    Science.gov (United States)

    Arakelyan, S. M.; Veiko, V. P.; Kutrovskaya, S. V.; Kucherik, A. O.; Osipov, A. V.; Vartanyan, T. A.; Itina, T. E.

    2016-06-01

    We report the results of continuous wave laser interactions with both gold and silver targets in the presence of different liquids (deionized water, ethanol, and glycerol). Upon moderate laser irradiation at wavelength of 1.06 nm during 30 min, nanoparticle colloids are shown to be formed with surprisingly narrow size distributions and average dispersion as small as 15-20 nm. The average particle sizes range between 8 and 52 nm for gold and between 20 and 107 nm for silver. This parameter is shown to be stable and well-controlled by such laser parameters as intensity and effective irradiation time, as well as by the choice of the liquid phase. The possibilities of an efficient control over the proposed synthesis techniques are discussed, and the results of a bimetallic Au-Ag structure deposition from the obtained colloids are presented. The formation of the extended arrays of gold and silver nanoparticles with controlled morphology is examined. The changes in the optical properties of the obtained thin films are found to depend on their morphology, in particular, on the particle size, and distance between them.

  16. Method of forming metal hydride films

    Science.gov (United States)

    Steinberg, R.; Alger, D. L.; Cooper, D. W. (Inventor)

    1977-01-01

    The substrate to be coated (which may be of metal, glass or the like) is cleaned, both chemically and by off-sputtering in a vacuum chamber. In an ultra-high vacuum system, vapor deposition by a sublimator or vaporizer coats a cooled shroud disposed around the substrate with a thin film of hydride forming metal which getters any contaminant gas molecules. A shutter is then opened to allow hydride forming metal to be deposited as a film or coating on the substrate. After the hydride forming metal coating is formed, deuterium or other hydrogen isotopes are bled into the vacuum system and diffused into the metal film or coating to form a hydride of metal film. Higher substrate temperatures and pressures may be used if various parameters are appropriately adjusted.

  17. High Precision Metal Thin Film Liftoff Technique

    Science.gov (United States)

    Brown, Ari D. (Inventor); Patel, Amil A. (Inventor)

    2015-01-01

    A metal film liftoff process includes applying a polymer layer onto a silicon substrate, applying a germanium layer over the polymer layer to create a bilayer lift off mask, applying a patterned photoresist layer over the germanium layer, removing an exposed portion of the germanium layer, removing the photoresist layer and a portion of the polymer layer to expose a portion of the substrate and create an overhanging structure of the germanium layer, depositing a metal film over the exposed portion of the substrate and the germanium layer, and removing the polymer and germanium layers along with the overlaying metal film.

  18. Adhesion and friction of thin metal films

    Science.gov (United States)

    Buckley, D. H.

    1976-01-01

    Sliding friction experiments were conducted in vacuum with thin films of titanium, chromium, iron, and platinum sputter deposited on quartz or mica substrates. A single crystal hemispherically tipped gold slider was used in contact with the films at loads of 1.0 to 30.0 and at a sliding velocity of 0.7 mm/min at 23 C. Test results indicate that the friction coefficient is dependent on the adhesion of two interfaces, that between the film and its substrate and the slider and the film. There exists a relationship between the percent d bond character of metals in bulk and in thin film form and the friction coefficient. Oxygen can increase adhesive bonding of a metal film (platinum) to a substrate.

  19. Thin film metal-oxides

    CERN Document Server

    Ramanathan, Shriram

    2009-01-01

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

  20. Adhesion of rhodium films on metallic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Marot, L. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)], E-mail: laurent.marot@unibas.ch; Covarel, G.; Tuilier, M.-H. [Laboratoire Mecanique, Materiaux et Procedes de Fabrication, Pole STIC-SPI-Math 61 rue Albert Camus, Universite de Haute-Alsace, F-68093 - Mulhouse Cedex (France); Steiner, R.; Oelhafen, P. [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland)

    2008-09-01

    Rhodium coated metallic films were prepared by magnetron sputtering on metallic substrates. All films were elaborated in same conditions on copper, molybdenum and stainless steel. Adhesion strength tests were carried out by scratch test. The results reveal that the adhesion strength between the film and the substrate is influenced by the hardness of the substrate. Increase of deposition temperature improves the adhesion of the coating. In addition, pre-treatment of substrates by a filtered cathodic vacuum arc and the layer thickness have has some effects on the final adhesion strength.

  1. Thin Metallic Films from Solvated Metal Atoms.

    Science.gov (United States)

    1987-07-14

    research has developed over the past two decades that deals with the generation of atoms of metals (by metal evaporation, and the interaction of these...Departamento de Quimica , Universidad de Concepcion, Cassilla 3-:, c oncepcion, Chile. -I{ - ~ *~.’JS*~M 4 .~4\\ 821 19 the gold particles were negatively...flocculation were observed, as shown in table a Generally about 0.1 g In was Suspended in 100-200 nl solvent. Several approacies to characterization of

  2. Electric field mapping inside metallized film capacitors

    DEFF Research Database (Denmark)

    Nielsen, Dennis Achton; Popok, Vladimir; Pedersen, Kjeld

    2015-01-01

    and durability and serves as verification that failure- and degradation mechanisms remain the same at different stress levels during accelerated testing. In this work we have used Kelvin probe force microscopy (KPFM) to analyze metallized film capacitors with the purpose of determining the degradation mechanism......(s) they suffered from accelerated testing. We have prepared film capacitors for analysis by micro-sectioning and verified the quality of the preparation procedure using optical and atomic force microscopy. The potential distribution in the layer structure (alternating 7 µm thick dielectric and 50-100 nm thick...... of the metallization stripes had lost contact to the end-spray. Thus, it is shown that the surface electric potential distributions on micro-sectioned film capacitors can be obtained through KPFM analysis. We have, from KPFM measurements, shown that the degraded capacitors under investigation had suffered from...

  3. Quantum metal film in the dielectric environment

    Science.gov (United States)

    Babich, A. V.; Pogosov, V. V.

    2013-01-01

    A method has been proposed for self-consistent calculations of characteristics of a metal film in dielectrics. The most interesting (asymmetric) case of metal-dielectric sandwiches, where the dielectrics are different on both sides of the film, has been considered in terms of the modified Kohn-Sham method and the stabilized jellium model. The spectrum, electron work function, and surface energy of polycrystalline films placed in passive insulators have been calculated for the first time using Al and Na as an example. It has been found that the dielectric environment generally leads to a negative change in both the electron work function and the surface energy. In addition to the size changes, the shift of the work function is determined by the arithmetic mean of the dielectric constants of the surrounding media.

  4. Energetic deposition of thin metal films

    CERN Document Server

    Al-Busaidy, M S K

    2001-01-01

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

  5. Metal films with imprinted nanostructures by template stripping

    DEFF Research Database (Denmark)

    Eriksen, René Lynge; Pors, Anders; Dreier, Jes

    We present a novel template stripping procedure for fabricating metal films with imprinted nanostructures. The basic idea is to deposit a gold film onto a nano-structured substrate and subsequently strip the film from the substrate surface thereby revealing imprinted nanostructures in the film...... result is a thin gold film with imprinted nano-cavities....

  6. Nanoscale growth twins in sputtered metal films

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Amit [Los Alamos National Laboratory; Anderoglu, Osman [Los Alamos National Laboratory; Hoagland, Richard G [Los Alamos National Laboratory; Zhang, X [TEXAS A& M

    2008-01-01

    We review recent studies on the mechanical properties of sputtered Cu and 330 stainless steel films with {l_brace}1 1 1{r_brace} nanoscale growth twins preferentially oriented perpendicular to growth direction. The mechanisms of formation of growth twins during sputtering and the deformation mechanisms that enable usually high strengths in nanotwinned structures are highlighted. Growth twins in sputtered films possess good thermal stability at elevated temperature, providing an approach to extend the application of high strength nanostructured metals to higher temperatures.

  7. Metallic Biosorption Using Yeasts in Continuous Systems

    Directory of Open Access Journals (Sweden)

    Karla Miriam Hernández Mata

    2013-01-01

    Full Text Available Mining effluents were found to be the main source of pollution by heavy metals of the surface water in the San Pedro River in Sonora, Mexico. The overall objective of this study was to determine the biosorption of Zn, Cu, Mn, and Fe with yeasts isolated from San Pedro River in a continuous system. The tests conducted in two reactors packed with zeolite connected in series. The first reactor was inoculated mixing two yeasts species, and the effluent of the first reactor was fed to second reactor. Subsequently, the first reactor was fed with contaminated water of San Pedro River and effluent from this was the second reactor influent. After 40 days of the experiment a reduction of 81.5% zinc, 76.5% copper, manganese 95.5%, and 99.8% of iron was obtained. These results show that the selected yeasts are capable of biosorbing zinc, copper, manganese, and iron under these conditions.

  8. Electrical resistivity of thin metal films

    CERN Document Server

    Wissmann, Peter

    2007-01-01

    The aim of the book is to give an actual survey on the resistivity of thin metal and semiconductor films interacting with gases. We discuss the influence of the substrate material and the annealing treatment of the films, presenting our experimental data as well as theoretical models to calculate the scattering cross section of the conduction electrons in the frame-work of the scattering hypothesis. Main emphasis is laid on the comparison of gold and silver films which exhibit nearly the same lattice structure but differ in their chemical activity. In conclusion, the most important quantity for the interpretation is the surface charging z while the correlation with the optical data or the frustrated IR vibrations seems the show a more material-specific character. Z can be calculated on the basis of the density functional formalism or the self-consistent field approximation using Mulliken’s population analysis.

  9. Electron impinging on metallic thin film targets

    Energy Technology Data Exchange (ETDEWEB)

    Rouabah, Z. [Laboratoire de Physique Moleculaire et des Collisions, ICPMB (FR CNRS 2843), Institut de Physique, Universite Paul Verlaine-Metz, Metz Cedex 3 (France); Laboratoire Materiaux et Systemes Electroniques, Centre Universitaire de Bordj-Bou-Arreridj, El-Anasser, 34265 Bordj-Bou-Arreridj (Algeria); Bouarissa, N., E-mail: N_Bouarissa@yahoo.fr [Department of Physics, Faculty of Science, King Khalid University, Abha, P.O.Box 9004 (Saudi Arabia); Champion, C. [Laboratoire de Physique Moleculaire et des Collisions, ICPMB (FR CNRS 2843), Institut de Physique, Universite Paul Verlaine-Metz, Metz Cedex 3 (France)

    2010-03-15

    Based on the Vicanek and Urbassek theory [M. Vicanek, H.M. Urbassek, Phys. Rev. B 44 (1991) 7234] combined to a home-made Monte Carlo simulation, the present work deals with backscattering coefficients, mean penetration depths and stopping profiles for 1-4 keV electrons normally incident impinging on Al and Cu thin film targets. The cross-sections used to describe the electron transport are calculated via the appropriate analytical expression given by Jablonski [A. Jablonski, Phys. Rev. B 58 (1998) 16470] whose new improved version has been recently given [Z. Rouabah, N. Bouarissa, C. Champion, N. Bouaouadja, Appl. Surf. Sci. 255 (2009) 6217]. The behavior of the backscattering coefficient, mean penetration depth and stopping profiles versus the metallic film thickness at the nanometric scale and beyond is here analyzed and discussed.

  10. Room temperature ferroelectricity in continuous croconic acid thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xuanyuan; Lu, Haidong; Yin, Yuewei; Ahmadi, Zahra; Costa, Paulo S. [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Zhang, Xiaozhe [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Department of Physics, Xi' an Jiaotong University, Xi' an 710049 (China); Wang, Xiao; Yu, Le; Cheng, Xuemei [Department of Physics, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010 (United States); DiChiara, Anthony D. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Gruverman, Alexei, E-mail: alexei-gruverman@unl.edu, E-mail: a.enders@me.com, E-mail: xiaoshan.xu@unl.edu; Enders, Axel, E-mail: alexei-gruverman@unl.edu, E-mail: a.enders@me.com, E-mail: xiaoshan.xu@unl.edu; Xu, Xiaoshan, E-mail: alexei-gruverman@unl.edu, E-mail: a.enders@me.com, E-mail: xiaoshan.xu@unl.edu [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588 (United States); Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588 (United States)

    2016-09-05

    Ferroelectricity at room temperature has been demonstrated in nanometer-thin quasi 2D croconic acid thin films, by the polarization hysteresis loop measurements in macroscopic capacitor geometry, along with observation and manipulation of the nanoscale domain structure by piezoresponse force microscopy. The fabrication of continuous thin films of the hydrogen-bonded croconic acid was achieved by the suppression of the thermal decomposition using low evaporation temperatures in high vacuum, combined with growth conditions far from thermal equilibrium. For nominal coverages ≥20 nm, quasi 2D and polycrystalline films, with an average grain size of 50–100 nm and 3.5 nm roughness, can be obtained. Spontaneous ferroelectric domain structures of the thin films have been observed and appear to correlate with the grain patterns. The application of this solvent-free growth protocol may be a key to the development of flexible organic ferroelectric thin films for electronic applications.

  11. Continuous wave infrared laser deposition of organic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yaginuma, Seiichiro [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503 (Japan); Yamaguchi, Jun [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503 (Japan); Haemori, Masamitsu [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503 (Japan); Itaka, Kenji [Department of Advanced Materials Science, Graduate School of Frontier Sciences, Univesity of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568 (Japan); Matsumoto, Yuji [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503 (Japan); Kondo, Michio [Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503 (Japan); Koinuma, Hideomi [Department of Advanced Materials Science, Graduate School of Frontier Sciences, Univesity of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568 (Japan)

    2007-04-15

    We developed a continuous-wave infrared laser molecular beam epitaxy (CW-IR-LMBE) optimized for the fabrication of organic semiconductor films. The crystal quality of these organic thin films deposited by CW-IR-LMBE was substantially the same as those deposited by thermal evaporation. Due to the possibility of quick switching of evaporation sources, CW-IR-LMBE is especially advantageous for rapid screening of composition, thickness, and fabrication parameters in materials and device optimization based on combinatorial technology.

  12. Plasmonic metamaterials based on holey metallic films

    Energy Technology Data Exchange (ETDEWEB)

    Mary, A; GarcIa-Vidal, F J [Departamento de Fisica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Rodrigo, Sergio G; Martin-Moreno, L [Departamento de Fisica de la Materia Condensada-ICMA, Universidad de Zaragoza-CSIC, E-50009 Zaragoza (Spain)], E-mail: fj.garcia@uam.es

    2008-07-30

    In this paper we address from the fundamental point of view the links and relations between three different phenomena that emerge when metallic films are perforated with periodic arrays of holes: (i) the phenomenon of extraordinary optical transmission in single metallic layers, (ii) the appearance of surface electromagnetic modes (the so-called spoof surface plasmons) when an array of holes is drilled on the surface of a perfect electrical conductor and (iii) the negative refractive index behavior observed in double-fishnet (DF) structures in which a periodic hole array is perforated on a metal-dielectric-metal stack. By using a very simple theoretical framework, we show how the physical origin of the negative refractive index in these DF structures is due to the excitation of spoof gap surface plasmon modes that propagate within the dielectric slab. We also demonstrate that the electrical response of the DF system is mainly controlled by the cut-off frequency of the hole waveguide. Finally, we present some results for multilayered DF structures that illustrate how the negative refractive index is maintained when several DF units are stacked together.

  13. Superconductor to Quantum Metal Transitions in Ultra Thin Films

    Science.gov (United States)

    Lin, Yen-Hsiang; Goldman, Allen M.

    2009-03-01

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

  14. Quenched transmission of light through ultrathin metal films

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Mortensen, N. Asger

    2011-01-01

    We discuss optical properties of ultrathin metal films, with particular attention to the phenomenon of quenched transmission. Transmission of light through an optically ultrathin metal film with a thickness comparable to its skin depth is significant. We demonstrate the quenched transmission thro...

  15. Nanostructured films of metal particles obtained by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Muniz-Miranda, M., E-mail: muniz@unifi.it [Dipartimento di Chimica “U. Schiff”, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Gellini, C. [Dipartimento di Chimica “U. Schiff”, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Giorgetti, E.; Margheri, G.; Marsili, P. [Istituto Sistemi Complessi (CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Lascialfari, L.; Becucci, L. [Dipartimento di Chimica “U. Schiff”, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Trigari, S. [Istituto Sistemi Complessi (CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Giammanco, F. [Dipartimento di Fisica “E. Fermi”, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy)

    2013-09-30

    Colloidal dispersions of silver and gold nanoparticles were obtained in pure water by ablation with nanosecond pulsed laser. Then, by filtration of the metal particles on alumina, we fabricated nanostructured films, whose surface morphology was examined by atomic force microscopy (AFM) and related to surface-enhanced Raman scattering (SERS) after adsorption of adenine. - Highlights: • Ag and Au colloidal nanoparticles were obtained by laser ablation. • Nanostructured Ag and Au films were fabricated by filtration of metal nanoparticles. • Surface morphology of metal films was investigated by atomic force microscopy. • Surface-enhanced Raman spectra (SERS) of adenine on metal films were obtained. • SERS enhancements were related to the surface roughness of the metal films.

  16. Growth of oriented rare-earth-transition-metal thin films

    Energy Technology Data Exchange (ETDEWEB)

    Fullerton, E.E.; Sowers, C.H.; Bader, S.D. [Argonne National Lab., IL (United States); Wu, X.Z. [Argonne National Lab., IL (United States)]|[Northern Illinois Univ., DeKalb, IL (United States)

    1996-04-01

    Rare-earth-transition-metal thin films are successfully grown by magnetron sputtering onto single-crystal MgO substrates with epitaxial W buffer layers. The use of epitaxial W buffer layers allows oriented single-phase films to be grown. Sm-Co films grown onto W(100), have strong in-plane anisotropy and coercivities exceeding 5 T at 5 K whereas Fe-Sm films have strong perpendicular anisotropy and are magnetically soft.

  17. High Critical Current in Metal Organic Derived YBCO Films

    Science.gov (United States)

    2010-10-31

    Contract No. FA9550-07-C-0034 “High Critical Current in Metal Organic Derived YBCO Films” Final Report Prepared for: Dr. Harold...Critical Current in Metal Organic Derived YBCO Films 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...Project focused on optimization of the Metal Organic Deposition (MOD) process for deposition thick, high critical current YBCO films for use in the

  18. Optically Thin Metallic Films for High-radiative-efficiency Plasmonics

    CERN Document Server

    Yang, Yi; Hsu, Chia Wei; Miller, Owen D; Joannopoulos, John D; Soljačić, Marin

    2016-01-01

    Plasmonics enables deep-subwavelength concentration of light and has become important for fundamental studies as well as real-life applications. Two major existing platforms of plasmonics are metallic nanoparticles and metallic films. Metallic nanoparticles allow efficient coupling to far field radiation, yet their synthesis typically leads to poor material quality. Metallic films offer substantially higher quality materials, but their coupling to radiation is typically jeopardized due to the large momentum mismatch with free space. Here, we propose and theoretically investigate optically thin metallic films as an ideal platform for high-radiative-efficiency plasmonics. For far-field scattering, adding a thin high-quality metallic substrate enables a higher quality factor while maintaining the localization and tunability that the nanoparticle provides. For near-field spontaneous emission, a thin metallic substrate, of high quality or not, greatly improves the field overlap between the emitter environment and ...

  19. The electrical conductivity of polycrystalline metallic films

    Science.gov (United States)

    Moraga, Luis; Arenas, Claudio; Henriquez, Ricardo; Bravo, Sergio; Solis, Basilio

    2016-10-01

    We calculate the electrical conductivity of polycrystalline metallic films by means of a semi-numerical procedure that provides solutions of the Boltzmann transport equation, that are essentially exact, by summing over classical trajectories according to Chambers' method. Following Mayadas and Shatzkes (MS), grain boundaries are modeled as an array of parallel plane barriers situated perpendicularly to the direction of the current. Alternatively, according to Szczyrbowski and Schmalzbauer (SS), the model consists in a triple array of these barriers in mutual perpendicular directions. The effects of surface roughness are described by means of Fuchs' specularity parameters. Following SS, the scattering properties of grain boundaries are taken into account by means of another specularity parameter and a probability of coherent passage. The difference between the sum of these and one is the probability of diffuse scattering. When this formalism is compared with the approximate formula of Mayadas and Shatzkes (Phys. Rev. B 1, 103 (1986)) it is shown that the latter greatly overestimates the film resistivity over most values of the reflectivity of the grain boundaries. The dependence of the conductivity of thin films on the probability of coherent passage and grain diameters is examined. In accordance with MS we find that the effects of disorder in the distribution of grain diameters is quite small. Moreover, we find that it is not safe to neglect the effects of the scattering by the additional interfaces created by stacked grains. However, when compared with recent resitivity-thickness data, it is shown that all three formalisms can provide accurate fits to experiment. In addition, it is shown that, depending on the respective reflectivities and distance from a surface, some of these interfaces may increase or diminish considerably the conductivity of the sample. As an illustration of this effect, we show a tentative fit of resistivity data of gold films measured by

  20. Pr-based metallic glass films used as resist for phase-change lithography.

    Science.gov (United States)

    Luo, Teng; Li, Zhen; He, Qiang; Miao, Xiangshui

    2016-03-21

    Metallic glass film of Pr60Al10Ni10Cu20 is proposed to be used as a resist of phase-change lithography (PCL). PCL is a mask-less lithography technology by using laser-direct-writing to create the intended nanopatterns. Thermal distribution in the PrAlNiCu film after exposure is calculated by finite element method (FEM). Thin films are exposed by continuous-wave laser and selective etched by nitric-acid solution, and the patterns are discerned by optical and atomic force microscope. The etching rate of as-deposited PrAlNiCu is thus nearly five times of the crystalline film. These results indicate that PrAlNiCu metallic glass film is a promising resist for phase-change lithography.

  1. Formation of arrayed holes on metal foil and metal film by multibeam interfering femtosecond laser beams

    Institute of Scientific and Technical Information of China (English)

    Zhao Quan-Zhong; Qiu Jian-Rong; Zhao Chong-Jun; Jiang Xiong-Wei; Zhu Cong-Shan

    2005-01-01

    We report on an optical interference method to fabricate arrayed holes on metal nickel foil and aluminum film deposited on glass substrate by means of five-beam interference of femtosecond laser pulses. Optical microscope and scanning electron microscope observations revealed that arrayed holes of micrometre-order were fabricated on both metal foil and metal film. The present technique allows one-step, large-area, micrometric processing of metal materials for potential industrial applications.

  2. Microscale mechanics for metal thin film delamination along ceramic substrates

    Institute of Scientific and Technical Information of China (English)

    魏悦广

    2000-01-01

    The metal thin film delamination along metal/ceramic interface in the case of large scale yielding is studied by employing the strain gradient plasticity theory and the material microscale effects are considered. Two different f racture process models are used in this study to describe the nonlinear delamination phenomena for metal thin films. A set of experiments have been done on the mechanism of copper films delaminating from silica substrates, based on which the peak interface separation stress and the micro-length scale of material, as well as the dislocation-free zone size are predicted.

  3. Microscale mechanics for metal thin film delamination along ceramic substrates

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The metal thin film delamination along metal/ceramic interface in the case of large scale yielding is studied by employing the strain gradient plasticity theory and the material microscale effects are considered.Two different fracture process models are used in this study to describe the nonlinear delamination phenomena for metal thin films.A set of experiments have been done on the mechanism of copper films delaminating from silica substrates,based on which the peak interface separation stress and the micro-length scale of material,as well as the dislocation-free zone size are predicted.

  4. Model for continuous thermal metal to insulator transition

    Science.gov (United States)

    Jian, Chao-Ming; Bi, Zhen; Xu, Cenke

    2017-09-01

    We propose a d -dimensional interacting Majorana fermion model with quenched disorder, which gives us a continuous quantum phase transition between a diffusive thermal metal phase with a finite entropy density to an insulator phase with zero entropy density. This model is based on coupled Sachdev-Ye-Kitaev model clusters, and hence has a controlled large-N limit. The metal-insulator transition is accompanied by a spontaneous time-reversal symmetry breaking. We perform controlled calculations to show that the energy diffusion constant jumps to zero discontinuously at the metal-insulator transition, while the time-reversal symmetry-breaking order parameter increases continuously.

  5. Transmission enhancement based on strong interference in metal-semiconductor layered film for energy harvesting

    Science.gov (United States)

    Li, Qiang; Du, Kaikai; Mao, Kening; Fang, Xu; Zhao, Ding; Ye, Hui; Qiu, Min

    2016-01-01

    A fundamental strategy to enhance optical transmission through a continuous metallic film based on strong interference dominated by interface phase shift is developed. In a metallic film coated with a thin semiconductor film, both transmission and absorption are simultaneously enhanced as a result of dramatically reduced reflection. For a 50-nm-thick Ag film, experimental transmission enhancement factors of 4.5 and 9.5 are realized by exploiting Ag/Si non-symmetric and Si/Ag/Si symmetric geometries, respectively. These planar layered films for transmission enhancement feature ultrathin thickness, broadband and wide-angle operation, and reduced resistance. Considering one of their potential applications as transparent metal electrodes in solar cells, a calculated 182% enhancement in the total transmission efficiency relative to a single metallic film is expected. This strategy relies on no patterned nanostructures and thereby may power up a wide spectrum of energy-harvesting applications such as thin-film photovoltaics and surface photocatalysis. PMID:27404510

  6. Characteristic properties of the Casimir free energy for metal films deposited on metallic plates

    Science.gov (United States)

    Klimchitskaya, G. L.; Mostepanenko, V. M.

    2016-04-01

    The Casimir free energy and pressure of thin metal films deposited on metallic plates are considered using the Lifshitz theory and the Drude and plasma model approaches to the role of conduction electrons. The bound electrons are taken into account by using the complete optical data of film and plate metals. It is shown that for films of several tens of nanometers thickness the Casimir free energy and pressure calculated using these approaches differ by hundreds and thousands percent and can be easily discriminated experimentally. According to our results, the free energy of a metal film does not vanish in the limiting case of ideal metal if the Drude model approach is used in contradiction with the fact that the fluctuating field cannot penetrate in its interior. Numerical computations of the Casimir free energy and pressure of Ag and Au films deposited on Cu and Al plates have been performed using both theoretical approaches. It is shown that the free energy of a film can be both negative and positive depending on the metals used. For a Au film on a Ag plate and vice versa the Casimir energy of a film changes its sign with increasing film thickness. Applications of the obtained results for resolving the Casimir puzzle and the problem of stability of thin films are discussed.

  7. Metallic glass thin films for potential biomedical applications.

    Science.gov (United States)

    Kaushik, Neelam; Sharma, Parmanand; Ahadian, Samad; Khademhosseini, Ali; Takahashi, Masaharu; Makino, Akihiro; Tanaka, Shuji; Esashi, Masayoshi

    2014-10-01

    We introduce metallic glass thin films (TiCuNi) as biocompatible materials for biomedical applications. TiCuNi metallic glass thin films were deposited on the Si substrate and their structural, surface, and mechanical properties were investigated. The fabricated films showed good biocompatibility upon exposure to muscle cells. Also, they exhibited an average roughness of films was shown to be free from Ni and mainly composed of a thin titanium oxide layer, which resulted in the high surface biocompatibility. In particular, there was no cytotoxicity effect of metallic glass films on the C2C12 myoblasts and the cells were able to proliferate well on these substrates. Low cost, viscoelastic behavior, patternability, high electrical conductivity, and the capability to coat various materials (e.g., nonbiocompatible materials) make TiCuNi as an attractive material for biomedical applications.

  8. Estimation of termostability of metal containing polymer films

    Directory of Open Access Journals (Sweden)

    Sh. Аmerkhanova

    2012-03-01

    Full Text Available The Derivatographic Analysis of metal containing polymer films based on polyvinyl alcohol was carried out, on these results the kinetic parameters of thermal destruction of the material was been calculated.

  9. Multifunctional, Nanostructured Metal Rubber Protective Films for Space Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NanoSonic has developed revolutionary nanostructured, yet macroscale, multifunctional Metal RubberTM films. In support of NASA's Vision for Space Exploration, low...

  10. Comparison of metallization systems for thin film hybrid microcircuits

    Energy Technology Data Exchange (ETDEWEB)

    Hines, R.A.; Raut, M.K.

    1980-08-01

    Five metallization systems were evaluated for fabricating thin film hybrid microcircuits. The titanium/palladium/electroplated gold system proved superior in terms of thermocompression bondability, corrosion resistance, and solderability.

  11. Passive films on metallic biomaterials under simulated physiological conditions.

    Science.gov (United States)

    Pound, B G

    2014-05-01

    The metallic materials used for implantable medical devices are predominantly stainless steels, Ti and its alloys, and Co-Cr alloys. The corrosion resistance of each of these materials is associated with a passive oxide film on its surface. Since corrosion resistance is crucial to implant performance, considerable effort has been focused on understanding the nature of the passive film present under physiological conditions. Surface analytical techniques and electrochemical impedance spectroscopy have been used in a number of studies to investigate the passive film formed on metallic biomaterials in simulated physiological solutions. This review focuses on the surface characteristics of these materials with regard to composition, thickness, and impedance of the passive films. Of particular interest are changes in the films with surface treatment and the nature of the films developed over time in the simulated solutions. Copyright © 2013 Wiley Periodicals, Inc.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-29

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

  13. Metallic Thin-Film Bonding and Alloy Generation

    Science.gov (United States)

    Fryer, Jack Merrill (Inventor); Campbell, Geoff (Inventor); Peotter, Brian S. (Inventor); Droppers, Lloyd (Inventor)

    2016-01-01

    Diffusion bonding a stack of aluminum thin films is particularly challenging due to a stable aluminum oxide coating that rapidly forms on the aluminum thin films when they are exposed to atmosphere and the relatively low meting temperature of aluminum. By plating the individual aluminum thin films with a metal that does not rapidly form a stable oxide coating, the individual aluminum thin films may be readily diffusion bonded together using heat and pressure. The resulting diffusion bonded structure can be an alloy of choice through the use of a carefully selected base and plating metals. The aluminum thin films may also be etched with distinct patterns that form a microfluidic fluid flow path through the stack of aluminum thin films when diffusion bonded together.

  14. Novel metal-carbon(60) nanocrystalline magnetic thin films

    Science.gov (United States)

    Zheng, Lingyi

    1999-11-01

    A novel type of nanocrystalline magnetic thin films consisting of ferromagnetic metals and C60 have been developed and investigated. CO-C 60, Fe-C60 and CoFe-C60 with different concentrations of C60 thin films have been manufactured by thermal vapor codeposition. The microstructures and magnetic properties of the films can be significantly enhanced by varying the concentrations of C60 in the films. The stability of C60 and the compatibility of C60 with the metallic matrices are confirmed by mass spectrometry, Raman, WDS, XRD and TEM. Strong metal- C60 interaction is indicated by higher desorption temperatures of C60 in the meta- C60 films than that in pure C60 and the peak shift in Raman spectra. TEM shows that the grain size of the matrix metal decreases proportionally with increasing C60 concentration. Nanosize uniform columnar grains with nanoscale dispersion of C60 on the grain boundaries are commonly observed in the metal-C60 films. A self- assembly grain growth model based on the size effect of C60 and the metal-C60 interaction is proposed to delineate the microstructural evolution by C60. Calculations based on this model are consistent with experimental observations and give a grain size vs. C60 (carbon) concentration relationship. Grain growth retardation by C60 is observed in a CO-C60 film. Out-plane magnetic remanence and coercivity are enhanced in both the CO-C60 and Fe-C60 films. In the in-plane direction, the coercivity deceases in CO- C60 films but increases slightly in Fe- C60 films with increasing C60 concentrations. In-plane magnetic anisotropy is detected in CO-C60 films but not in Fe-C60 films. Strong temperature-dependent magnetization remanence and saturation are found in both the Co- C60 and Fe-C60 films with high C60 concentrations due to the nanosize grain effects. Temperature effects on the coercivity of CO- C60 and Fe-C60 are different and determined by the intrinsic magnetocrystalline anisotropy energy. Coercivity of the CoFe-C60 films

  15. Cobalt(I) Olefin Complexes: Precursors for Metal-Organic Chemical Vapor Deposition of High Purity Cobalt Metal Thin Films.

    Science.gov (United States)

    Hamilton, Jeff A; Pugh, Thomas; Johnson, Andrew L; Kingsley, Andrew J; Richards, Stephen P

    2016-07-18

    We report the synthesis and characterization of a family of organometallic cobalt(I) metal precursors based around cyclopentadienyl and diene ligands. The molecular structures of the complexes cyclopentadienyl-cobalt(I) diolefin complexes are described, as determined by single-crystal X-ray diffraction analysis. Thermogravimetric analysis and thermal stability studies of the complexes highlighted the isoprene, dimethyl butadiene, and cyclohexadiene derivatives [(C5H5)Co(η(4)-CH2CHC(Me)CH2)] (1), [(C5H5)Co(η(4)-CH2C(Me)C(Me)CH2)] (2), and [(C5H5)Co(η(4)-C6H8)] (4) as possible cobalt metal organic chemical vapor deposition (MOCVD) precursors. Atmospheric pressure MOCVD was employed using precursor 1, to synthesize thin films of metallic cobalt on silicon substrates under an atmosphere (760 torr) of hydrogen (H2). Analysis of the thin films deposited at substrate temperatures of 325, 350, 375, and 400 °C, respectively, by scanning electron microscopy and atomic force microscopy reveal temperature-dependent growth features. Films grown at these temperatures are continuous, pinhole-free, and can be seen to be composed of hexagonal particles clearly visible in the electron micrograph. Powder X-ray diffraction and X-ray photoelectron spectroscopy all show the films to be highly crystalline, high-purity metallic cobalt. Raman spectroscopy was unable to detect the presence of cobalt silicides at the substrate/thin film interface.

  16. Thin-film silicon for flexible metal-air batteries.

    Science.gov (United States)

    Garamoun, Ahmed; Schubert, Markus B; Werner, Jürgen H

    2014-12-01

    Due to its high energy density, theoretical studies propose silicon as a promising candidate material for metal-air batteries. Herein, for the first time, experimental results detail the use of n-type doped amorphous silicon and silicon carbide as fuel in Si-air batteries. Thin-film silicon is particularly interesting for flexible and rolled batteries with high specific energies. Our Si-air batteries exhibit a specific capacity of 269 Ah kg(-1) and an average cell voltage of 0.85 V at a discharge current density of 7.9 μA cm(-2) , corresponding to a specific energy of 229 Wh kg(-1) . Favorably in terms of safety, low concentrated alkaline solution serves as electrolyte. Discharging of the Si-air cells continues as long as there is silicon available for oxidation.

  17. Transferred metal electrode films for large-area electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jin-Guo [Department of Physics, National University of Singapore, Lower Kent Ridge Road, Singapore S117543 (Singapore); NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, Medical Drive, Singapore S117456 (Singapore); Kam, Fong-Yu [Department of Chemistry, National University of Singapore, Lower Kent Ridge Road, Singapore S117543 (Singapore); Chua, Lay-Lay [Department of Chemistry, National University of Singapore, Lower Kent Ridge Road, Singapore S117543 (Singapore); Department of Physics, National University of Singapore, Lower Kent Ridge Road, Singapore S117543 (Singapore)

    2014-11-10

    The evaporation of metal-film gate electrodes for top-gate organic field-effect transistors (OFETs) limits the minimum thickness of the polymer gate dielectric to typically more than 300 nm due to deep hot metal atom penetration and damage of the dielectric. We show here that the self-release layer transfer method recently developed for high-quality graphene transfer is also capable of giving high-quality metal thin-film transfers to produce high-performance capacitors and OFETs with superior dielectric breakdown strength even for ultrathin polymer dielectric films. Dielectric breakdown strengths up to 5–6 MV cm{sup −1} have been obtained for 50-nm thin films of polystyrene and a cyclic olefin copolymer TOPAS{sup ®} (Zeon). High-quality OFETs with sub-10 V operational voltages have been obtained this way using conventional polymer dielectrics and a high-mobility polymer semiconductor poly[2,5-bis(3-tetradecylthiophene-2-yl)thieno[3,2-b]thiophene-2,5-diyl]. The transferred metal films can make reliable contacts without damaging ultrathin polymer films, self-assembled monolayers and graphene, which is not otherwise possible from evaporated or sputtered metal films.

  18. Nearly zero transmission through periodically modulated ultrathin metal films

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Zhang, Jingjing; Peng, Liang;

    2010-01-01

    Transmission of light through an optically ultrathin metal film with a thickness comparable to its skin depth is significant. We demonstrate experimentally nearly-zero transmission of light through a film periodically modulated by a one-dimensional array of subwavelength slits. The suppressed opt...

  19. Stress in and texture of PVD deposited metal nitride films

    NARCIS (Netherlands)

    Machunze, R.

    2010-01-01

    Thin metal nitride films deposited by Physical Vapor Deposition (PVD) are used amongst many other applications as wear protective coatings in tool industry or as diffusion barriers in integrated circuit technology. Typically these films exhibit a residual in-plane stress when deposited onto rigid su

  20. A comparison of surface properties of metallic thin film photocathodes

    CERN Document Server

    Mistry, Sonal; Valizadeh, Reza; Jones, L.B; Middleman, Keith; Hannah, Adrian; Militsyn, B.L; Noakes, Tim

    2017-01-01

    In this work the preparation of metal photocathodes by physical vapour deposition magnetron sputtering has been employed to deposit metallic thin films onto Cu, Mo and Si substrates. The use of metallic cathodes offers several advantages: (i) metal photocathodes present a fast response time and a relative insensitivity to the vacuum environment (ii) metallic thin films when prepared and transferred in vacuum can offer smoother and cleaner emitting surfaces. The photocathodes developed here will ultimately be used in S-band Normal Conducting RF (NCRF) guns such as that used in VELA (Versatile Electron Linear Accelerator) and the proposed CLARA (Compact Linear Accelerator for Research and Applications) Free Electron Laser test facility. The samples grown on Si substrates were used to investigate the morphology and thickness of the film. The samples grown onto Cu and Mo substrates were analysed and tested as photocathodes in a surface characterisation chamber, where X-Ray Photoelectron spectroscopy (XPS) was em...

  1. Ubiquitous pentacene monolayer on metals deposited onto pentacene films.

    Science.gov (United States)

    Jaeckel, B; Sambur, J B; Parkinson, B A

    2007-11-01

    Photoelectron spectroscopy (XPS and UPS) was used to study the deposition of metal layers (Ag, Cu, and Au) onto pentacene films. Very low work functions were measured (PhiAg = 3.91 eV, PhiCu = 3.93 eV, and PhiAu = 4.3 eV) for all of the metals, in agreement with results from the literature. The intensities of the C 1s core-level signals from pentacene that were monitored during stepwise metal deposition leveled off at a value of about 30% of a thick pentacene film. This C 1s intensity is comparable to that of one monolayer of pentacene deposited onto the respective metal. The valence band spectra of metals deposited onto pentacene and spectra collected for pentacene deposited onto bare metal surfaces are very similar. These findings lead to the conclusion that approximately one monolayer of pentacene is always present on top of the freshly deposited metal film, which explains the very low work function of the metals when they are deposited onto organic films. We expect similar behavior with other nonreactive metals deposited onto stable organic layers.

  2. Harnessing Thin-Film Continuous-Flow Assembly Lines.

    Science.gov (United States)

    Britton, Joshua; Castle, Jared W; Weiss, Gregory A; Raston, Colin L

    2016-07-25

    Inspired by nature's ability to construct complex molecules through sequential synthetic transformations, an assembly line synthesis of α-aminophosphonates has been developed. In this approach, simple starting materials are continuously fed through a thin-film reactor where the intermediates accrue molecular complexity as they progress through the flow system. Flow chemistry allows rapid multistep transformations to occur via reaction compartmentalization, an approach not amenable to using conventional flasks. Thin film processing can also access facile in situ solvent exchange to drive reaction efficiency, and through this method, α-aminophosphonate synthesis requires only 443 s residence time to produce 3.22 g h(-1) . Assembly-line synthesis allows unprecedented reaction flexibility and processing efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Soap film dynamics and topological jumps under continuous deformation

    Science.gov (United States)

    Moffatt, Keith

    2015-11-01

    Consider the dynamics of a soap-film bounded by a flexible wire (or wires) which can be continuously and slowly deformed. At each instant the soap-film relaxes in quasi-static manner to a minimum-area (i.e. minimum-energy) state compatible with the boundary configuration. This can however pass through a critical configuration at which a topological jump is inevitable. We have studied an interesting example of this behaviour: the jump of a one-sided (Möbius strip) soap-film to a two-sided film as the boundary is unfolded and untwisted from the double cover of a circle. The nature of this jump will be demonstrated and explained. More generally, dynamical systems have a natural tendency to relax through dissipative processes to a minimum-energy state, subject to any relevant constraints. An example is provided by the relaxation of a magnetic field in a perfectly conducting but viscous fluid, subject to the constraint that the magnetic field lines are frozen in the fluid. One may infer the existence of magnetostatic equilibria (and analogous steady Euler flows) of arbitrary field-line topology. In general, discontinuities (current sheets) appear during this relaxation process, and this is where reconnection of field-lines (with associated change of topology) can occur. Just as for the soap film, slow change of boundary conditions can lead to critical conditions in which such topological jumps are inevitable. (Work in collaboration with Ray Goldstein, Adriana Pesci, Renzo Ricca and Gareth Alexander.) This work was supported by Engineering and Physical Sciences Research Council Grant EP/I036060/1.

  4. New chemistry for the growth of first-row transition metal films by atomic layer deposition

    Science.gov (United States)

    Klesko, Joseph Peter

    Thin films containing first-row transition metals are widely used in microelectronic, photovoltaic, catalytic, and surface-coating applications. In particular, metallic films are essential for interconnects and seed, barrier, and capping layers in integrated circuitry. Traditional vapor deposition methods for film growth include PVD, CVD, or the use of plasma. However, these techniques lack the requisite precision for film growth at the nanoscale, and thus, are increasingly inadequate for many current and future applications. By contrast, ALD is the favored approach for depositing films with absolute surface conformality and thickness control on 3D architectures and in high aspect ratio features. However, the low-temperature chemical reduction of most first-row transition metal cations to their zero-valent state is very challenging due to their negative electrochemical potentials. A lack of strongly-reducing coreagents has rendered the thermal ALD of metallic films an intractable problem for many elements. Additionally, several established ALD processes for metal films are plagued by low growth rates, impurity incorporation, poor nucleation, high surface roughness, or the need for hazardous coreagents. Finally, stoichiometric control of ternary films grown by ALD is rare, but increasingly important, with emerging applications for metal borate films in catalysis and lithium ion batteries. The research herein is focused toward the development of new ALD processes for the broader application of metal, metal oxide, and metal borate thin films to future nanoscale technologies. These processes display self-limited growth and support the facile nucleation of smooth, continuous, high-purity films. Bis(trimethylsilyl) six-membered rings are employed as strongly-reducing organic coreagents for the ALD of titanium and antimony metal films. Additionally, new processes are developed for the growth of high-purity, low-resistivity cobalt and nickel metal films by exploiting the

  5. Characteristic time scales of coalescence of silver nanocomposite and nanoparticle films induced by continuous wave laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Paeng, Dongwoo; Grigoropoulos, Costas P., E-mail: cgrigoro@berkeley.edu [Department of Mechanical Engineering, University of California Berkeley, Berkeley, California 94720-1740 (United States); Lee, Daeho [Department of Mechanical Engineering, Gachon University, Seongnam-si, Gyeonggi-do 461-701 (Korea, Republic of)

    2014-08-18

    In-situ optical probing has been performed to analyze and compare the characteristic coalescence time scales of silver ion-doped polyvinylalcohol nanocomposite (Ag-PVA NC) and polyvinylpyrrolidone-capped silver nanoparticle (Ag-PVP NP) films subjected to continuous wave laser irradiation. The Ag-PVA NC yielded conductive metallic patterns by photothermal reduction of PVA, formation of nanoparticles from silver ions and their subsequent coalescence. On the other hand, Ag-PVP NP thin films produced conductive patterns through only coalescence of nanoparticles. Upon laser irradiation, Ag-PVA NC and Ag-PVP NP films exhibited different coalescence characteristics.

  6. Dielectric interlayers for increasing the transparency of metal films for mid-infrared attenuated total reflection spectroscopy.

    Science.gov (United States)

    Reithmeier, Martina; Erbe, Andreas

    2010-11-28

    By depositing a continuous, thin metal film on a substrate coated with a mid-infrared (IR) transparent dielectric film that fulfils the role of an index-matching, anti-reflective coating for the metal, the transparency of the metal in the IR wavelength range can be significantly enhanced. This effect is used to yield enhanced absorption in attenuated total internal reflection infrared (ATR-IR) spectroscopy in the presence of continuous thin metal films. The main limitation of the ATR technique when using continuous metal films is the low transparency of metals, especially for infrared light. Computations and experiments show an enhancement in the absorbance of a sample in contact with the metal at certain wavenumbers when the dielectric interlayer is present. The realisation of the setup is the stratified system consisting of zinc selenide-germanium (~1 μm)-gold (40 nm and 20 nm) using the organic solvent acetonitrile as sample. Enhancement is stronger in s- than in p-polarisation. In s-polarisation, enhancement factors of up to 4 have been observed so far in experiments, but calculations show a route to higher enhancements. In addition to the increased absorption, the absorbance spectra show interference fringes which are due to a mismatch in the real part of the refractive index of the sample in contact with the metal film compared to a reference measurement.

  7. Metal-insulator transition in films of doped semiconductor nanocrystals.

    Science.gov (United States)

    Chen, Ting; Reich, K V; Kramer, Nicolaas J; Fu, Han; Kortshagen, Uwe R; Shklovskii, B I

    2016-03-01

    To fully deploy the potential of semiconductor nanocrystal films as low-cost electronic materials, a better understanding of the amount of dopants required to make their conductivity metallic is needed. In bulk semiconductors, the critical concentration of electrons at the metal-insulator transition is described by the Mott criterion. Here, we theoretically derive the critical concentration nc for films of heavily doped nanocrystals devoid of ligands at their surface and in direct contact with each other. In the accompanying experiments, we investigate the conduction mechanism in films of phosphorus-doped, ligand-free silicon nanocrystals. At the largest electron concentration achieved in our samples, which is half the predicted nc, we find that the localization length of hopping electrons is close to three times the nanocrystals diameter, indicating that the film approaches the metal-insulator transition.

  8. Density functional study of ferromagnetism in alkali metal thin films

    Indian Academy of Sciences (India)

    Prasenjit Sen

    2010-04-01

    Electronic and magnetic structures of (1 0 0) films of K and Cs, having thicknesses of one to seven layers, are calculated within the plane-wave projector augmented wave (PAW) formalism of the density functional theory (DFT), using both local spin density approximation (LSDA) and the PW91 generalized gradient approximation (GGA). Only a six-layer Cs film is found to have a ferromagnetic (FM) state which is degenerate with a paramagnetic (PM) state within the accuracy of these calculations. These results are compared with those obtained from calculations on a finite-thickness uniform jellium model (UJM), and it is argued that within LSDA or GGA, alkali metal thin films cannot be claimed to have an FM ground state. Relevance of these results to the experiments on transition metal-doped alkali metal thin films and bulk hosts are also discussed.

  9. Nonlinear absorption of ultrashort laser pulses in thin metal films

    CERN Document Server

    Manfredi, G; Manfredi, Giovanni; Paul-Antoine Hervieux

    2005-01-01

    Self-consistent simulations of the ultrafast electron dynamics in thin metal films are performed. A regime of nonlinear oscillations is observed, which corresponds to ballistic electrons bouncing back and forth against the film surfaces. When an oscillatory laser field is applied to the film, the field energy is partially absorbed by the electron gas. Maximum absorption occurs when the period of the external field matches the period of the nonlinear oscillations, which, for sodium films, lies in the infrared range. Possible experimental implementations are discussed.

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

    Science.gov (United States)

    Hwang, Seulgi; Kim, Youngman

    2011-08-01

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

  11. Ultraviolet-induced erasable photochromism in bilayer metal oxide films

    Science.gov (United States)

    Terakado, Nobuaki; Tanaka, Keiji; Nakazawa, Akira

    2011-09-01

    We demonstrate that the optical transmittance of bilayer samples consisting of pyrolytically coated amorphous Mg-Sn-O and metal oxide films such as In 2O 3 and SnO 2 decreases upon ultraviolet illumination, but can be recovered by annealing in air at ˜300 ∘C. Spectral, structural, and compositional studies suggest that this photochromic phenomenon is induced by photoelectronic excitation in the Mg-Sn-O film, electron injection into the metal oxide, which becomes negatively charged, and subsequent formation of metallic particles, which absorb and/or scatter visible light.

  12. Continuous Carbon Nanotube-Based Fibers and Films for Applications Requiring Enhanced Heat Dissipation.

    Science.gov (United States)

    Liu, Peng; Fan, Zeng; Mikhalchan, Anastasiia; Tran, Thang Q; Jewell, Daniel; Duong, Hai M; Marconnet, Amy M

    2016-07-13

    The production of continuous carbon nanotube (CNT) fibers and films has paved the way to leverage the superior properties of individual carbon nanotubes for novel macroscale applications such as electronic cables and multifunctional composites. In this manuscript, we synthesize fibers and films from CNT aerogels that are continuously grown by floating catalyst chemical vapor deposition (FCCVD) and measure thermal conductivity and natural convective heat transfer coefficient from the fiber and film. To probe the mechanisms of heat transfer, we develop a new, robust, steady-state thermal characterization technique that enables measurement of the intrinsic fiber thermal conductivity and the convective heat transfer coefficient from the fiber to the surrounding air. The thermal conductivity of the as-prepared fiber ranges from 4.7 ± 0.3 to 28.0 ± 2.4 W m(-1) K(-1) and depends on fiber volume fraction and diameter. A simple nitric acid treatment increases the thermal conductivity by as much as a factor of ∼3 for the fibers and ∼6.7 for the thin films. These acid-treated CNT materials demonstrate specific thermal conductivities significantly higher than common metals with the same absolute thermal conductivity, which means they are comparatively lightweight, thermally conductive fibers and films. Beyond thermal conductivity, the acid treatment enhances electrical conductivity by a factor of ∼2.3. Further, the measured convective heat transfer coefficients range from 25 to 200 W m(-2) K(-1) for all fibers, which is higher than expected for macroscale materials and demonstrates the impact of the nanoscale CNT features on convective heat losses from the fibers. The measured thermal and electrical performance demonstrates the promise for using these fibers and films in macroscale applications requiring effective heat dissipation.

  13. Polymer-assisted deposition of metal-oxide films.

    Science.gov (United States)

    Jia, Q X; McCleskey, T M; Burrell, A K; Lin, Y; Collis, G E; Wang, H; Li, A D Q; Foltyn, S R

    2004-08-01

    Metal oxides are emerging as important materials for their versatile properties such as high-temperature superconductivity, ferroelectricity, ferromagnetism, piezoelectricity and semiconductivity. Metal-oxide films are conventionally grown by physical and chemical vapour deposition. However, the high cost of necessary equipment and restriction of coatings on a relatively small area have limited their potential applications. Chemical-solution depositions such as sol-gel are more cost-effective, but many metal oxides cannot be deposited and the control of stoichiometry is not always possible owing to differences in chemical reactivity among the metals. Here we report a novel process to grow metal-oxide films in large areas at low cost using polymer-assisted deposition (PAD), where the polymer controls the viscosity and binds metal ions, resulting in a homogeneous distribution of metal precursors in the solution and the formation of uniform metal-organic films. The latter feature makes it possible to grow simple and complex crack-free epitaxial metal-oxides.

  14. Casimir free energy and pressure for magnetic metal films

    Science.gov (United States)

    Klimchitskaya, G. L.; Mostepanenko, V. M.

    2016-07-01

    We examine the Casimir free energy and pressure of magnetic metal films, which are free standing in vacuum, sandwiched between two dielectric plates and deposited on either nonmagnetic or magnetic metallic plates. All calculations are performed using both the Drude and plasma model approaches to the Lifshitz theory. According to our results, the Casimir free energies and pressures calculated using both theoretical approaches are significantly different in the magnitude and sign even for thin films of several tens of nanometers thickness. Thus, for the Ni film of 47 nm thickness deposited on a Fe plate the obtained magnitudes of the Casimir free energy differ by the factor of 5866. We show that the Casimir free energy and pressure of a magnetic film calculated using the plasma model approach do not possess the classical limit but exponentially fast drop to zero with increasing film thickness. If the Drude model approach is used, the classical limit is reached for magnetic films of about 150 nm thickness, but the Casimir free energy remains nonzero in the limit of ideal metal, contrary to expectations. For the plasma model approach the Casimir free energy of a film vanishes in this case. Numerical computations are performed for the magnetic films made of Ni, nonmagnetic plates made of Cu and Al, and magnetic plates made of Fe using the tabulated optical data for the complex indexes of refraction of all metals. The obtained results can be used for a discrimination between the plasma and Drude model approaches in the Casimir physics and in the investigation of stability of thin films.

  15. Electrochemical Characterization of Ultrathin Cross-Linked Metal Nanoparticle Films.

    Science.gov (United States)

    Han, Chu; Percival, Stephen J; Zhang, Bo

    2016-09-06

    Here we report the preparation, characterization, and electrochemical study of conductive, ultrathin films of cross-linked metal nanoparticles (NPs). Nanoporous films ranging from 40 to 200 nm in thickness composed of gold and platinum NPs of ∼5 nm were fabricated via a powerful layer-by-layer spin coating process. This process allows preparation of uniform NP films as large as 2 × 2 cm(2) with precise control over thickness, structure, and electrochemical and electrocatalytic properties. Gold, platinum, and bimetallic NP films were fabricated and characterized using cyclic voltammetry, scanning electron microscopy, and conductance measurements. Their electrocatalytic activity toward the oxygen reduction reaction (ORR) was investigated. Our results show that the electrochemical activity of such NP films is initially hindered by the presence of dense thiolate cross-linking ligands. Both electrochemical cycling and oxygen plasma cleaning are effective means in restoring their electrochemical activity. Gold NP films have higher electric conductivity than platinum possibly due to more uniform film structure and closer particle-particle distance. The electrochemical and electrocatalytic performance of platinum NP films can be greatly enhanced by the incorporation of gold NPs. This work focuses on electrochemical characterization of cross-linked NP films and demonstrates several unique properties. These include quick and easy preparation, ultrathin and uniform film thickness, tunable structure and composition, and transferability to many other substrates.

  16. Near- and far field spectroscopy of semi-continuous gold films with optically induced anisotropy

    DEFF Research Database (Denmark)

    Frydendahl, Christian; Repän, Taavi; Geisler, Mathias

    Using electron energy loss spectroscopy (EELS), optical spectroscopy, and finite element method simulations, we investigate the distributions of plasmonic modes present in fractal semi-continuous gold films, as well as studying anisotropy introduced into these films from photothermal melting...

  17. UV laser deposition of metal films by photogenerated free radicals

    Science.gov (United States)

    Montgomery, R. K.; Mantei, T. D.

    1986-01-01

    A novel photochemical method for liquid-phase deposition of metal films is described. In the liquid phase deposition scheme, a metal containing compound and a metal-metal bonded carbonyl complex are dissolved together in a polar solvent and the mixture is irradiated using a UV laser. The optical arrangement consists of a HeCd laser which provides 7 mW of power at a wavelength of 325 nm in the TEM(OO) mode. The beam is attenuated and may be expanded to a diameter of 5-20 mm. Experiments with photochemical deposition of silver films onto glass and quartz substrates are described in detail. Mass spectrometric analysis of deposited silver films indicated a deposition rate of about 1 A/s at incident power levels of 0.01 W/sq cm. UV laser-induced copper and palladium films have also been obtained. A black and white photograph showing the silver Van Der Pauw pattern of a solution-deposited film is provided.

  18. Performance testing of multi-metal continuous emissions monitors

    Energy Technology Data Exchange (ETDEWEB)

    Haas, W.J. [Ames Lab., IA (United States); French, N.B. [Sky+, Inc. (United States); Brown, C.H. [Oak Ridge National Lab., TN (United States); Burns, D.B. [Westinghouse Savannah River Co., Aiken, SC (United States); Lemieux, P.M.; Ryan, J.V. [National Risk Management Research Lab., Research Triangle Park, NC (United States); Priebe, S.J. [Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States); Waterland, L.R. [Acurex Environmental Corp. (United States)

    1997-11-17

    Three prototype multi-metals continuous emissions monitors (CEMs) were tested in April 1996 at the Rotary Kiln Incinerator Simulator facility at the US Environmental Protection Agency (EPA) National Risk Management Research Laboratory, Research Triangle Park, North Carolina. The CEM instruments were: Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES); Laser Induced Breakdown Spectrometry-Atomic Emission Spectroscopy (LIBS); and Laser Spark Spectrometry, another LIBS instrument. The three CEMs were tested simultaneously during test periods in which low, medium, and high concentration levels of seven toxic metals -- antimony, arsenic, beryllium, cadmium, chromium, lead, and mercury -- were maintained under carefully controlled conditions. Two methods were used to introduce the test metals into the flue gas: (1) solution atomization, introducing metal-containing aerosol directly into the secondary combustion burner, and (2) injection of fly ash particulates. The testing addressed four measures of CEM performance: relative accuracy (RA), calibration drift, zero drift, and response time. These were accomplished by comparing the toxic metal analyte concentrations reported by the CEMs to the concentrations measured using the EPA reference method (RM) for the same analytes. Overall, the test results showed the prototype nature of the test CEMs and the clear need for further development. None of the CEMs tested consistently achieved RA values of 20% or less as required by the EPA draft performance specification. Instrument size reduction and automation will also likely need additional attention before multi-metal CEMs systems become commercially available for service as envisioned by regulators and citizens.

  19. Effects of Inductance of the Metallization Removal of Exploding Films

    Science.gov (United States)

    2011-06-01

    wires are cylindrical and foils are physically robust and thicker than film. The film studied is capacitor - grade aluminum metallized polypropylene film...to discharge the energy of a capacitor to explode the MPPF. The diagram of the circuit is demonstrated in Figure. 1. A high-voltage dc power supply...Slaughter 122/125-2.5) is used to charge a 2 μF capacitor to 2.5 kV. Switch 1 is used here to disconnect the power supply from the discharge

  20. Effects of humidity during photoprocessing on thin film metallization adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Norwood, D.P.

    1980-03-01

    Humidity effects during photoprocessing on tantalum/chromium/gold thin film networks (TFNs) were investigated. Humidity conditions at various process steps were controlled by placing either desiccant or water in handling containers for the TFNs. The TFNs photoprocessed in humid conditions had a much higher occurrence of metallization failures compared to TFNs processed in dry conditions. Ceramic surface defects were shown to cause pores in the thin films, and these pores enhanced corrosion susceptibility for the films. This study resulted in a desiccated storage process for production of TFNs.

  1. Left-handed materials in magnetized metallic magnetic thin films

    Institute of Scientific and Technical Information of China (English)

    WU Rui-xin; XIAO John Q.

    2006-01-01

    The authors' theoretical investigation on the high-frequency response of magnetized metallic magnetic films showed that magnetic films may become left-handed materials (LHMs) near the ferromagnetic resonance frequency of incident waves with right-handed circular polarization (RCP) and linear polarization (LP). The frequency range where LHM exists depends on the waves polarization, the magnetic damping coefficient, and the ferromagnetic characteristic frequency ωm of the film. There also exists a critical damping coefficient αc, above which the left-handed properties disappear completely.

  2. Femtosecond damage threshold of multilayer metal films

    Science.gov (United States)

    Ibrahim, Wael M. G.; Elsayed-Ali, Hani E.; Shinn, Michelle D.; Bonner, Carl E.

    2003-05-01

    With the availability of terawatt laser systems with subpicosecond pulses, laser damage to optical components has become the limiting factor for further increases in the output peak power. Evaluation of different material structures in accordance to their suitability for high-power laser systems is essential. Multi-shot damage experiments, using 110 fs laser pulses at 800 nm, on polycrystalline single layer gold films and multi-layer (gold-vanadium, and gold-titanium) films were conducted. The laser incident fluence was varied, in both cases, from 0.1 to 0.6 J/cm2. No evidence of surface damage was apparent in the gold sample up to a fluence of 0.3 J/cm2. The multilayer sample experienced the onset of surface damage at the lowest fluence value used of 0.1 J/cm2. Damage results are in contrast with the time resolved ultrafast thermoreflectivity measurements that revealed a reduction of the thermoreflectivity signal for the multilayer films. This decrease in the thermoreflectivity signal signifies a reduction in the surface electron temperature that should translate in a lower lattice temperature at the later stage. Hence, one should expect a higher damage threshold for the multilayer samples. Comparison of the experimental results with the predictions of the Two-Temperature Model (TTM) is presented. The damage threshold of the single layer gold film corresponds to the melting threshold predicted by the model. In contrast to the single layer gold film, the multi-layer sample damaged at almost one third the damage threshold predicted by the TTM model. Possible damage mechanisms leading to the early onset of damage for the multilayer films are discussed.

  3. Column IIIA metal film deposition by dissociative photoionization of metal halide vapors

    Science.gov (United States)

    Geohegan, D. B.; Eden, J. G.

    1984-11-01

    Films of column IIIA metals (In, Al, and Tl) have been deposited on several different substrates (stainless steel, nickel, copper, and silver) by dissociatively photoionizing the corresponding metal iodide in a uniform electric field. Thin (≲0.2 μm) indium films have been grown on nickel by photoionizing indium monoiodide (InI) vapor with an argon fluoride (ArF) excimer laser at 193 nm. A similar process has resulted in thallium films produced from thallium iodide (TlI) vapor with a high pressure xenon lamp.

  4. Thermal transport across a continuous metal-insulator transition

    Science.gov (United States)

    Haldar, P.; Laad, M. S.; Hassan, S. R.

    2017-09-01

    The celebrated Wiedemann-Franz (WF) law is believed to be robust in metals as long as interactions between electrons preserve their fermion-quasiparticle character. We study thermal transport and the fate of the WF law close to a continuous metal-insulator transition (MIT) in the Falicov-Kimball model (FKM) using cluster-dynamical mean-field theory (CDMFT). Surprisingly, as for electrical transport, we find robust and novel quantum critical scaling in thermal transport across the MIT. We unearth the deeper reasons for these novel findings in terms of (i) the specific structure of energy-current correlations for the FKM and (ii) the microscopic electronic processes which facilitate energy transport while simultaneously blocking charge transport close to the MIT. However, within (C)DMFT, we also find that the WF law survives at T ⟶0 in the incoherent metal right up to the MIT, even in absence of Landau quasiparticles.

  5. Modeling of wide-area thin-film metal-semiconductor-metal photodetectors for LIDAR applications

    Science.gov (United States)

    Glinz, Andreas P.; Morrison, Charles B.; Zhu, Zheng

    1998-07-01

    We report calculations of the collection current of interdigitated InGaAs metal-semiconductor-metal photodetectors. We show how interdigital spacing and thickness of the semiconductor layer influence the collection current. Both front and back illumination of devices carried on thin film membranes by means of epitaxial liftoff are examined.

  6. Incipient plasticity in metallic thin films

    NARCIS (Netherlands)

    Soer, W. A.; De Hosson, J. Th. M.; Minor, A. M.; Shan, Z.; Asif, S. A. Syed; Warren, O. L.

    2007-01-01

    The authors have compared the incipient plastic behaviors of Al and Al-Mg thin films during indentation under load control and displacement control. In Al-Mg, solute pinning limits the ability of dislocations to propagate into the crystal and thus substantially affects the appearance of plastic inst

  7. Electron stimulated hydroxylation of a metal supported silicate film.

    Science.gov (United States)

    Yu, Xin; Emmez, Emre; Pan, Qiushi; Yang, Bing; Pomp, Sascha; Kaden, William E; Sterrer, Martin; Shaikhutdinov, Shamil; Freund, Hans-Joachim; Goikoetxea, Itziar; Wlodarczyk, Radoslaw; Sauer, Joachim

    2016-02-01

    Water adsorption on a double-layer silicate film was studied by using infrared reflection-absorption spectroscopy, thermal desorption spectroscopy and scanning tunneling microscopy. Under vacuum conditions, small amounts of silanols (Si-OH) could only be formed upon deposition of an ice-like (amorphous solid water, ASW) film and subsequent heating to room temperature. Silanol coverage is considerably enhanced by low-energy electron irradiation of an ASW pre-covered silicate film. The degree of hydroxylation can be tuned by the irradiation parameters (beam energy, exposure) and the ASW film thickness. The results are consistent with a generally accepted picture that hydroxylation occurs through hydrolysis of siloxane (Si-O-Si) bonds in the silica network. Calculations using density functional theory show that this may happen on Si-O-Si bonds, which are either parallel (i.e., in the topmost silicate layer) or vertical to the film surface (i.e., connecting two silicate layers). In the latter case, the mechanism may additionally involve the reaction with a metal support underneath. The observed vibrational spectra are dominated by terminal silanol groups (ν(OD) band at 2763 cm(-1)) formed by hydrolysis of vertical Si-O-Si linkages. Film dehydroxylation fully occurs only upon heating to very high temperatures (∼ 1200 K) and is accompanied by substantial film restructuring, and even film dewetting upon cycling hydroxylation/dehydroxylation treatment.

  8. Thin film pc-Si by aluminium induced crystallization on metallic substrate

    Directory of Open Access Journals (Sweden)

    Cayron C.

    2013-04-01

    Full Text Available Thin film polycrystalline silicon (pc-Si on flexible metallic substrates is promising for low cost production of photovoltaic solar cells. One of the attractive methods to produce pc-Si solar cells consists in thickening a large-grained seed layer by epitaxy. In this work, the deposited seed layer is made by aluminium induced crystallization (AIC of an amorphous silicon (a-Si thin film on metallic substrates (Ni/Fe alloy initially coated with a tantalum nitride (TaN conductive diffusion barrier layer. Effect of the thermal budget on the AIC grown pc-Si seed layer was investigated in order to optimize the process (i.e. the quality of the pc-Si thin film. Structural and optical characterizations were carried out using optical microscopy, μ-Raman and Electron Backscatter Diffraction (EBSD. At optimal thermal annealing conditions, the continuous AIC grown pc-Si thin film showed an average grain size around 15 μm. The grains were preferably (001 oriented which is favorable for its epitaxial thickening. This work proves the feasibility of the AIC method to grow large grains pc-Si seed layer on TaN coated metal substrates. These results are, in terms of grains size, the finest obtained by AIC on metallic substrates.

  9. Microwave induced elastic deformation of a metallic thin film

    CERN Document Server

    Wang, S B

    2013-01-01

    The microwave induced elastic deformation of a metallic thin film is computed numerically and we found that the deformation can be significantly enhanced at resonance. We show that an analytical transmission line model can reproduce the numerical results almost quantitatively and at the same time reveal the underlying physics.

  10. High-performance copper alloy films for barrierless metallization

    Science.gov (United States)

    Lin, C. H.; Leau, W. K.; Wu, C. H.

    2010-11-01

    In this study, we observe useful properties of V1.1- and V0.8N0.4-bearing copper (Cu) films deposited on barrierless silicon (Si) substrates by a cosputtering process. The Cu98.8(V0.8N0.4), or Cu(VNx) for brevity, films exhibit low resistivity (2.9 μΩ cm) and minimal leakage current after annealing at temperatures up to 700 °C for 1 h; no detectable reaction occurs at the Cu/Si interface. These observations confirm the high thermal stability of Cu(VNx) films. Furthermore, since these films have good adhesion features, they can be used for barrierless Cu metallization.

  11. Investigation of performance degradation in metallized film capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Godec, M. [Institute of Metals and Technology, Lepi Pot 11, 1000 Ljubljana (Slovenia); Mandrino, Dj., E-mail: djordje.mandrino@imt.si [Institute of Metals and Technology, Lepi Pot 11, 1000 Ljubljana (Slovenia); Gaberšček, M. [National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia)

    2013-05-15

    Zn–Al metallized film capacitors in two different production stages were investigated to explain the decrease of capacitors performance with time. Unsealed and sealed capacitors with different aluminium content in metallization layer were investigated. Scanning electron microscopy (SEM) was used to image the surface of the metallization layers, energy dispersive X-ray spectroscopy (EDS) was used to determine the chemical composition and Auger electron spectroscopy (AES) was used to determine the chemical composition of the top of the metallization layers as well as to estimate the degree of oxidation. It was found that air humidity degraded the metallization layer of unsealed capacitors, especially at lower Al contents. Sealed capacitors were exposed to high electric fields, typical for standard usage. It was found – rather unexpectedly – that the performance was decreased by increasing Al content. A crystallographic explanation was proposed.

  12. Investigation of performance degradation in metallized film capacitors

    Science.gov (United States)

    Godec, M.; Mandrino, Dj.; Gaberšček, M.

    2013-05-01

    Zn-Al metallized film capacitors in two different production stages were investigated to explain the decrease of capacitors performance with time. Unsealed and sealed capacitors with different aluminium content in metallization layer were investigated. Scanning electron microscopy (SEM) was used to image the surface of the metallization layers, energy dispersive X-ray spectroscopy (EDS) was used to determine the chemical composition and Auger electron spectroscopy (AES) was used to determine the chemical composition of the top of the metallization layers as well as to estimate the degree of oxidation. It was found that air humidity degraded the metallization layer of unsealed capacitors, especially at lower Al contents. Sealed capacitors were exposed to high electric fields, typical for standard usage. It was found - rather unexpectedly - that the performance was decreased by increasing Al content. A crystallographic explanation was proposed.

  13. Controlled delamination of metal films by hydrogen loading

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, Eugen

    2008-11-18

    n this work we quantitatively determine the adhesion energy between metal films and their substrates. Therefore a new controlled buckling technique is established, applying the strong compressive in-plane stress that results in thin films clamped on rigid substrates during hydrogen loading. When the elastic energy stored in the H-loaded thin film exceeds the adhesion energy between film and substrate, delamination occurs. At the onset of delamination, a critical hydrogen concentration, a critical stress value and a critical bending of the substrate are present, which are quantitative measures for the adhesion energy and permit its calculation. As the critical values are determined at the onset of delamination, plastic deformation is negligible, which denies the quantitative determination of adhesion energies in conventional test setups. In multilayer-systems, adhesion energies between substrates and films that hardly absorb hydrogen can be measured by the controlled buckling technique, when the films of interest are coated with hydrogen absorbing films (active layer). The measurements are performed easily and can be repeated under the same test conditions, while variables such as the thickness of the coating materials or the boundary surface structure can be varied and optimized. In this work the adhesion energies of different materials on polycarbonate and niobium on sapphire are investigated. (orig.)

  14. Quantum critical transport at a continuous metal-insulator transition

    Science.gov (United States)

    Haldar, P.; Laad, M. S.; Hassan, S. R.

    2016-08-01

    In contrast to the first-order correlation-driven Mott metal-insulator transition, continuous disorder-driven transitions are intrinsically quantum critical. Here, we investigate transport quantum criticality in the Falicov-Kimball model, a representative of the latter class in the strong disorder category. Employing cluster-dynamical mean-field theory, we find clear and anomalous quantum critical scaling behavior manifesting as perfect mirror symmetry of scaling curves on both sides of the MIT. Surprisingly, we find that the beta function β (g ) scales as log(g ) deep into the bad-metallic phase as well, providing a sound unified basis for these findings. We argue that such strong localization quantum criticality may manifest in real three-dimensional systems where disorder effects are more important than electron-electron interactions.

  15. Thin-film metal hydrides for solar energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Mongstad, Trygve Tveiteraas

    2012-11-01

    Thin-film metal hydrides may become important solar energy materials in the future. This thesis demonstrates interesting material properties of metal hydride films, relevant for applications as semiconducting materials for photovoltaic (PV) solar cells and for regulation of light using smart window technology.The work presented here has comprised an experimental study, focusing on three different materials: Magnesium hydride (MgH2), magnesium nickel hydride (Mg2NiH4) and yttrium hydride (YHx). Reactive sputter deposition was used to prepare the metal hydride film samples.This synthesis method is relatively uncommon for metal hydrides. Here,the first demonstration of reactive sputtering synthesis for YHx and Mg2NiH4 is given. Different challenges in forming singlephase, pure metal hydrides were identified: MgH2 could not be deposited without 3-16% metallic Mg present in the films, and YHx was found to react strong-ly to oxygen (O) during the deposition process. On the other hand, Mg2NiH4 films formed easily and apparently without major metallic clusters and with low O content.Mg2NiH4 is a semiconductor with an optical band gap that is suitable for PV solar cells. This study has showed that films with promising electrical and optical properties can be synthesized using reactive cosputtering of Mg and Ni. Using optical methods, the band gap for the as deposited samples was estimated to 1.54-1.76 eV, depending on the Mg-Ni composition. The asdeposited films were amorphous or nano-crystalline, but could be crystallized into the high-temperature fcc structure of Mg2NiH4 using heat treatment at 523 K. The band gap of the crystalline films was 2.1-2.2 eV, depending on the composition.A pronounced photochromic reaction to visible and UV light was observed for transparent yttrium hydride (T-YHx) samples. The optical transmission was reduced when the samples were illuminated, and the original optical transmission was restored when the samples were kept under dark conditions

  16. Metal oxide films on glass and steel substrates

    CERN Document Server

    Sohi, A M

    1987-01-01

    in the pH8 electrolyte supports the view that the rate limiting reduction reaction is possibly oxygen (or water) reduction although some contribution from an organic 'impurity' cannot be ruled out. Coatings of Fe sub 3 O sub 4 on mild steel have been prepared by CVD using pneumatic spraying techniques and the corrosion behaviour of coated electrodes in organic-phosphate electrolyte (pH8) has been examined. A variety of thin (10-1000nm) metal oxide films have been deposited on flat glass substrates by the pyrolysis of an aerosol of metal acetylacetonates in a suitable carrier. The optical characteristics and thickness of the films have been measured and particular interest has centered on the use of a novel pin on disc apparatus to measure the physical durability of such thin films. Characteristic friction/penetration force traces have been established for 1st Series transition metal oxide films and some ranking in terms of 'hardness' established. The use of SnO sub 2 - coated glass for electrodes in a light m...

  17. Nanomechanical investigation of thin-film electroceramic/metal-organic framework multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Best, James P., E-mail: james.best@empa.ch, E-mail: engelbert.redel@kit.edu, E-mail: christof.woell@kit.edu; Michler, Johann; Maeder, Xavier [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, CH-3602 Thun (Switzerland); Liu, Jianxi; Wang, Zhengbang; Tsotsalas, Manuel; Liu, Jinxuan; Gliemann, Hartmut; Weidler, Peter G.; Redel, Engelbert, E-mail: james.best@empa.ch, E-mail: engelbert.redel@kit.edu, E-mail: christof.woell@kit.edu; Wöll, Christof, E-mail: james.best@empa.ch, E-mail: engelbert.redel@kit.edu, E-mail: christof.woell@kit.edu [Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Röse, Silvana [Preparative Macromolecular Chemistry, Institute for Chemical Technology and Polymer Chemistry (ICTP), Karlsruhe Institute of Technology (KIT), Engesserstrasse 18, 76128 Karlsruhe (Germany); Institute for Biological Interfaces (IBG), Karlsruhe Institute of Technology (KIT), Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Oberst, Vanessa [Institute of Applied Materials (IAM), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Walheim, Stefan [Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2015-09-07

    Thin-film multilayer stacks of mechanically hard magnetron sputtered indium tin oxide (ITO) and mechanically soft highly porous surface anchored metal-organic framework (SURMOF) HKUST-1 were studied using nanoindentation. Crystalline, continuous, and monolithic surface anchored MOF thin films were fabricated using a liquid-phase epitaxial growth method. Control over respective fabrication processes allowed for tuning of the thickness of the thin film systems with a high degree of precision. It was found that the mechanical indentation of such thin films is significantly affected by the substrate properties; however, elastic parameters were able to be decoupled for constituent thin-film materials (E{sub ITO} ≈ 96.7 GPa, E{sub HKUST−1} ≈ 22.0 GPa). For indentation of multilayer stacks, it was found that as the layer thicknesses were increased, while holding the relative thickness of ITO and HKUST-1 constant, the resistance to deformation was significantly altered. Such an observation is likely due to small, albeit significant, changes in film texture, interfacial roughness, size effects, and controlling deformation mechanism as a result of increasing material deposition during processing. Such effects may have consequences regarding the rational mechanical design and utilization of MOF-based hybrid thin-film devices.

  18. Annealing-induced shape recovery in thin film metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Negussie, Alemu Tesfaye; Diyatmika, Wahyu [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Chu, J.P., E-mail: jpchu@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Shen, Y.L. [Department of Mechanical Engineering, University of New Mexico, Albuquerque, NM 87131 (United States); Jang, J.S.C. [Department of Mechanical Engineering, National Central University, Chung-Li 32001, Taiwan (China); Hsueh, C.H. [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-11-15

    Highlights: • Annealing-induced shape recovery of thin film metallic glass is examined. • Shape recovery becomes obvious with increasing temperature and holding time. • Minimum roughness is obtained when annealed within supercooled liquid region. • The amount of free volume in the film plays a role for the shape recovery. • The numerical simulation confirms the shape recovery upon annealing. - Abstract: The shape recovery property of a sputtered Zr{sub 50.3}Cu{sub 28.1}Al{sub 14}Ni{sub 7.6} (in at.%) thin film metallic glass upon heating is examined. Due to the surface tension-driven viscous flow, the shape of indentation appears to recover to different extents at various temperatures and holding times. It is found that a maximum of 59.8% indentation depth recovery is achieved after annealing within the supercooled liquid region (SCLR). The amount of free volume in the film is found to play a role in the recovery. Atomic force microscopy results reveal a decrease in film roughness to a minimum value within SCLR. To elucidate the experimentally observed shape recovery, a numerical modeling has been employed. It is evident that the depressed region caused by indentation is elevated after annealing.

  19. Optical properties of a metal island film close to a smooth metal surface.

    Science.gov (United States)

    Leitner, A; Zhao, Z; Brunner, H; Aussenegg, F R; Wokaun, A

    1993-01-01

    Bright colors have been observed when a metal island film is deposited on top of a silver mirror with a separating quartz layer. For spacer layer thicknesses that are varied from 0 to 140 nm, the visual appearance changes from blue/black to a series of brilliant spectrumlike colors. The sequence is repeated similarly for higher interlayer thicknesses. The phenomenon is analyzed in terms of a stratified medium theory by using TEM data and an electromagnetic model for the optical constants of the metal island film. For island films with a sufficiently high absorbance (> 0.35), the spectra are characterized by two sharp minima where the reflectivity drops to values below l0(-3). The observed thickness dependence is analyzed in terms of a complex combination of the phase shifts caused by the island film, the spacer, and the relevant interfaces.

  20. 1997 Performance Testing of Multi-Metal Continuous Emissions Monitors

    Energy Technology Data Exchange (ETDEWEB)

    Sky +, Inc.

    1998-09-01

    Five prototype and two commercially available multi-metals continuous emissions monitors (CEMs) were tested in September 1997 at the Rotary Kiln Incinerator Simulator facility at the EPA National Risk Management Research Laboratory, Research Triangle Park, North Carolina. The seven CEMs were tested side by side in a long section of duct following the secondary combustion chamber of the RKIS. Two different concentrations of six toxic metals were introduced into the incinerator-approximately 15 and 75 µg/dscm of arsenic, beryllium, cadmium, chromium, lead, and mercury (We also tested for antimony but we are not reporting on it here because EPA recently dropped antimony from the list of metals addressed by the draft MACT rule). These concentrations were chosen to be close to emission standards in the draft MACT rule and the estimated Method Detection Limit (MDL) required of a CEM for regulatory compliance purposes. Results from this test show that no CEMs currently meet the performance specifications in the EPA draft MACT rule for hazardous waste incinerators. Only one of the CEMs tested was able to measure all six metals at the concentrations tested. Even so, the relative accuracy of this CEM varied between 35% and 100%, not 20% or less as required in the EPA performance specification. As a result, we conclude that no CEM is ready for long-term performance validation for compliance monitoring applications. Because sampling and measuring Hg is a recurring problem for multi-metal CEMs as well as Hg CEMs, we recommended that developers participate in a 1998 DOE-sponsored workshop to solve these and other common CEM measurement issues.

  1. Non-metallic Inclusions in Continuously Cast Aluminum Killed Steels

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In aluminum killed steels, the size, shape, quantity and formation of non-metallic inclusions in ladle steel (before and after RH vacuum treatment) and in tundish as well as in slabs were studied by EPMA (Electron Probe Microanalysis) and by analyzing the total oxygen. The results showed that in the slabs the total oxygen was quite low and the inclusions discovered were mainly small-sized angular alumina inclusions. This indicates that most inclusions have been removed by floating out during the continuous casting process. In addition, the countermeasures were discussed to decrease the alumina inclusions in the slabs further.

  2. Induced electric fields and plasmonic interactions between a metallic nanotube and a thin metallic film

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We have numerically simulated the induced electric fields and the plasmonic interactions of a metallic nanotube near a thin metallic film. Our study shows that the energies and intensities of the plasmon resonances depend strongly on the aspect ratio (the ratio of the inner to outer radius) of the nanotube as well as the separation between the center of the nanotube and the upper surface of the metallic film and the thickness of the film. The enhancement of the induced electric field of this system reaches as high as 10 4 orders of magnitude and its field distribution is characterized by waveguide-mode resonance. The report proposes that these phenomena can be applied to designing surface enhanced spectroscopies such as surface enhanced Raman spectroscopy for efficient chemical and biological sensing.

  3. Synthesis of metal-organic framework films by pore diffusion method

    Science.gov (United States)

    Murayama, Naohiro; Nishimura, Yuki; Kajiro, Hiroshi; Kishida, Satoru; Kinoshita, Kentaro; Tottori Univ Team; Nippon Steel; Sumitomo Metal Co. Collaboration; Tottori Integrated Frontier Resaerch Center (Tifrec) Collaboration; Tottori University Electronic Display Resaerch Center (Tedrec) Collaboration

    Metal-organic frameworks (MOFs) presents high controllability in designing the nano-scale pore, and this enable molecular storages, catalysts, gas sensors, gas separation membranes, and electronic devices for next-generation. Therefore, a simple method for film synthesis of MOFs compared with conventional methods [1] is strongly required. In this paper, we provide pore diffusion method, in which a substrate containing constituent metals of MOF is inserted in solution that includes only linker molecules of MOF. As a result, 2D growth of MOF was effectively enhanced, and the formation of flat and dense MOF films was attained. The growth time, t, dependence of film thickness, d, can be expressed by the relation of d = Aln(t + 1) + B, where A and B are constants. It means that ionized coppers diffuse through the pores of MOFs and the synthesis reaction proceeds at the MOF/solvent interface. We demonstrated the fabrication of a HKUST-1/Cu-TPA hetero structure by synthesizing a Cu-TPA film continuously after the growth of a HKUST-1 film on the CuOx substrate.

  4. Nonlocal effect in surface plasmon polariton of ultrathin metal films

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Hong-jie; Yu, Yabin, E-mail: apybyu@hnu.edu.cn; Wu, Reng-lai; Yu, Yan-qin; Wang, Ya-xin

    2015-09-01

    Using the nonlocal conductivity based on quantum response theory, we study the optical properties of p-polarized wave in quartz–metal–film–air structures, especially the influence of nonlocal effect on the surface plasmon polaritons (SPPs) resonance. In absorption spectrum, the resonant peak of SPP is found, and the dependence of the resonant peak on film thickness shows that nonlocal effect in the SPP resonance is enhanced significantly with the decrease of film-thickness, especially in the less than 20 nm metal film. We calculate the surface charge density as a function of frequency, and find that the frequencies at the charge and absorption peaks are the same. This clearly confirms that the absorption peak stems from SPP resonance excitation, and SPPs absorb the energy of the electromagnetic wave via charge oscillations. In the case of SPP resonance, the charge and electric field on the down-surface of thin film are always greater than that on the up-surface; however, the situation is just opposite in the case of no SPP resonance. This implies that the SPP resonance occurs near the down-surface of the film. Moreover, due to the nonlocal response of electric current to the electric field, the energy flow and electric current show anomalous oscillations, and with the increase of film thickness the anomalous oscillations exhibit obvious attenuation.

  5. A high-performance, flexible and robust metal nanotrough-embedded transparent conducting film for wearable touch screen panels

    Science.gov (United States)

    Im, Hyeon-Gyun; An, Byeong Wan; Jin, Jungho; Jang, Junho; Park, Young-Geun; Park, Jang-Ung; Bae, Byeong-Soo

    2016-02-01

    We report a high-performance, flexible and robust metal nanotrough-embedded transparent conducting hybrid film (metal nanotrough-GFRHybrimer). Using an electro-spun polymer nanofiber web as a template and vacuum-deposited gold as a conductor, a junction resistance-free continuous metal nanotrough network is formed. Subsequently, the metal nanotrough is embedded on the surface of a glass-fabric reinforced composite substrate (GFRHybrimer). The monolithic composite structure of our transparent conducting film allows simultaneously high thermal stability (24 h at 250 °C in air), a smooth surface topography (Rrms touch screen panel (TSP) is fabricated using the transparent conducting films. The flexible TSP device stably operates on the back of a human hand and on a wristband.We report a high-performance, flexible and robust metal nanotrough-embedded transparent conducting hybrid film (metal nanotrough-GFRHybrimer). Using an electro-spun polymer nanofiber web as a template and vacuum-deposited gold as a conductor, a junction resistance-free continuous metal nanotrough network is formed. Subsequently, the metal nanotrough is embedded on the surface of a glass-fabric reinforced composite substrate (GFRHybrimer). The monolithic composite structure of our transparent conducting film allows simultaneously high thermal stability (24 h at 250 °C in air), a smooth surface topography (Rrms touch screen panel (TSP) is fabricated using the transparent conducting films. The flexible TSP device stably operates on the back of a human hand and on a wristband. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07657a

  6. Reversible metal-hydride phase transformation in epitaxial films.

    Science.gov (United States)

    Roytburd, Alexander L; Boyerinas, Brad M; Bruck, Hugh A

    2015-03-11

    Metal-hydride phase transformations in solids commonly proceed with hysteresis. The extrinsic component of hysteresis is the result of the dissipation of energy of internal stress due to plastic deformation and fracture. It can be mitigated on the nanoscale, where plastic deformation and fracture are suppressed and the transformation proceeds through formation and evolution of coherent phases. However, the phase coherency introduces intrinsic thermodynamic hysteresis, preventing reversible transformation. In this paper, it is shown that thermodynamic hysteresis of coherent metal-hydride transformation can be eliminated in epitaxial film due to substrate constraint. Film-substrate interaction leads to formation of heterophase polydomain nanostructure with variable phase fraction which can change reversibly by varying temperature in a closed system or chemical potential in an open system.

  7. Green nanochemistry: metal oxide nanoparticles and porous thin films from bare metal powders.

    Science.gov (United States)

    Redel, Engelbert; Petrov, Srebri; Dag, Omer; Moir, Jonathon; Huai, Chen; Mirtchev, Peter; Ozin, Geoffrey A

    2012-01-01

    A universal, simple, robust, widely applicable and cost-effective aqueous process is described for a controlled oxidative dissolution process of micrometer-sized metal powders to form high-purity aqueous dispersions of colloidally stable 3-8 nm metal oxide nanoparticles. Their utilization for making single and multilayer optically transparent high-surface-area nanoporous films is demonstrated. This facile synthesis is anticipated to find numerous applications in materials science, engineering, and nanomedicine.

  8. Metallic and Ceramic Thin Film Thermocouples for Gas Turbine Engines

    OpenAIRE

    Gregory, Otto J.; Matin Amani; Ian M. Tougas

    2013-01-01

    Temperatures of hot section components in today’s gas turbine engines reach as high as 1,500 °C, making in situ monitoring of the severe temperature gradients within the engine rather difficult. Therefore, there is a need to develop instrumentation (i.e., thermocouples and strain gauges) for these turbine engines that can survive these harsh environments. Refractory metal and ceramic thin film thermocouples are well suited for this task since they have excellent chemical and electrical stabil...

  9. Thermal simulation for geometric optimization of metallized polypropylene film capacitors

    OpenAIRE

    El-Husseini, M.,; Venet, Pascal; Rojat, Gérard; Joubert, Charles

    2002-01-01

    In this paper, we use an analytic model to calculate the losses in the metallized polypropylene film capacitors. The model is validated experimentally for capacitors having the same capacitance but different geometry. For each group of capacitors a temperature distribution in the roll is assumed with the aim of optimizing its thermal performance. It appears that the heating of a long capacitor is higher than that of an equivalent flat capacitor subjected to the same electric stresses.

  10. Domain evolution and polarization of continuously graded ferroelectric films

    Energy Technology Data Exchange (ETDEWEB)

    Roytburd, A.; Roytburd, V.

    2008-01-01

    A thermodynamic analysis of graded ferroelectric films demonstrates that in the equilibrium state the films are subdivided into a single-domain band and a polydomain band which consists of wedge-shape domains. Polarization under an external electrostatic field proceeds through an inter-band boundary movement due to growth or shrinkage of the wedge domains. It is shown how the domain structure and evolution are determined by the principal characteristics of the film: the distribution of the spontaneous polarization and dielectric constant. Graded films exhibit a sharp increase of polarization with the field for weak fields, with a drop of the dielectric constant when the field is increasing. A general approach to finding the dependence of the displacement and the wedge-domain shape on the field as well as analytical solutions for the p{sup 4} Landau-Devonshire and parabolic potentials are presented.

  11. Metallic and ceramic thin film thermocouples for gas turbine engines.

    Science.gov (United States)

    Tougas, Ian M; Amani, Matin; Gregory, Otto J

    2013-11-08

    Temperatures of hot section components in today's gas turbine engines reach as high as 1,500 °C, making in situ monitoring of the severe temperature gradients within the engine rather difficult. Therefore, there is a need to develop instrumentation (i.e., thermocouples and strain gauges) for these turbine engines that can survive these harsh environments. Refractory metal and ceramic thin film thermocouples are well suited for this task since they have excellent chemical and electrical stability at high temperatures in oxidizing atmospheres, they are compatible with thermal barrier coatings commonly employed in today's engines, they have greater sensitivity than conventional wire thermocouples, and they are non-invasive to combustion aerodynamics in the engine. Thin film thermocouples based on platinum:palladium and indium oxynitride:indium tin oxynitride as well as their oxide counterparts have been developed for this purpose and have proven to be more stable than conventional type-S and type-K thin film thermocouples. The metallic and ceramic thin film thermocouples described within this paper exhibited remarkable stability and drift rates similar to bulk (wire) thermocouples.

  12. Metallic and Ceramic Thin Film Thermocouples for Gas Turbine Engines

    Directory of Open Access Journals (Sweden)

    Otto J. Gregory

    2013-11-01

    Full Text Available Temperatures of hot section components in today’s gas turbine engines reach as high as 1,500 °C, making in situ monitoring of the severe temperature gradients within the engine rather difficult. Therefore, there is a need to develop instrumentation (i.e., thermocouples and strain gauges for these turbine engines that can survive these harsh environments. Refractory metal and ceramic thin film thermocouples are well suited for this task since they have excellent chemical and electrical stability at high temperatures in oxidizing atmospheres, they are compatible with thermal barrier coatings commonly employed in today’s engines, they have greater sensitivity than conventional wire thermocouples, and they are non-invasive to combustion aerodynamics in the engine. Thin film thermocouples based on platinum:palladium and indium oxynitride:indium tin oxynitride as well as their oxide counterparts have been developed for this purpose and have proven to be more stable than conventional type-S and type-K thin film thermocouples. The metallic and ceramic thin film thermocouples described within this paper exhibited remarkable stability and drift rates similar to bulk (wire thermocouples.

  13. Amorphous semiconducting and conducting transparent metal oxide thin films and production thereof

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, John (Boulder, CO); Van Hest, Marinus Franciscus Antonius Maria (Lakewood, CO); Ginley, David (Evergreen, CO); Taylor, Matthew (Golden, CO); Neuman, George A. (Holland, MI); Luten, Henry A. (Holland, MI); Forgette, Jeffrey A. (Hudsonville, MI); Anderson, John S. (Holland, MI)

    2010-07-13

    Metal oxide thin films and production thereof are disclosed. An exemplary method of producing a metal oxide thin film may comprise introducing at least two metallic elements and oxygen into a process chamber to form a metal oxide. The method may also comprise depositing the metal oxide on a substrate in the process chamber. The method may also comprise simultaneously controlling a ratio of the at least two metallic elements and a stoichiometry of the oxygen during deposition. Exemplary amorphous metal oxide thin films produced according to the methods herein may exhibit highly transparent properties, highly conductive properties, and/or other opto-electronic properties.

  14. Binary metal oxide nanoparticle incorporated composite multilayer thin films for sono-photocatalytic degradation of organic pollutants

    Science.gov (United States)

    Gokul, Paramasivam; Vinoth, Ramalingam; Neppolian, Bernaurdshaw; Anandhakumar, Sundaramurthy

    2017-10-01

    We report reduced graphene oxide (rGO) supported binary metal oxide (CuO-TiO2/rGO) nanoparticle (NP) incorporated multilayer thin films based on Layer-by-Layer (LbL) assembly for enhanced sono-photocatalytic degradation of methyl orange under exposure to UV radiation. Multilayer thin films were fabricated on glass and quartz slides, and investigated using scanning electron microscopy and UV-vis spectroscopy. The loading of catalyst NPs on the film resulted in the change of morphology of the film from smooth to rough with uniformly distributed NPs on the surface. The growth of the control and NP incorporated films followed a linear regime as a function of number of layers. The%degradation of methyl orange as a function of time was investigated by UV-vis spectroscopy and total organic carbon (TOC) measurements. Complete degradation of methyl orange was achieved within 13 h. The amount of NP loading in the film significantly influenced the%degradation of methyl orange. Catalyst reusability studies revealed that the catalyst thin films could be repeatedly used for up to five times without any change in photocatalytic activity of the films. The findings of the present study support that the binary metal oxide catalyst films reported here are very useful for continuous systems, and thus, making it an option for scale up.

  15. MHD Effect of Liquid Metal Film Flows as Plasma-Facing Components

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiujie; XU Zengyu; PAN Chuanjie

    2008-01-01

    Stability of liquid metal film flow under gradient magnetic field is investigated. Three dimensional numerical simulations on magnetohydrodynamics (MHD) effect of free surface film flow were carried out, with emphasis on the film thickness variation and its surface stability. Three different MHD phenomena of film flow were observed in the experiment, namely, retardant, rivulet and flat film flow. From our experiment and numerical simulation it can be concluded that flat film flow is a good choice for plasma-facing components (PFCs)

  16. Thin films of metal oxides on metal single crystals: Structure and growth by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Galloway, Heather Claire [Univ. of California, Berkeley, CA (United States)

    1995-12-01

    Detailed studies of the growth and structure of thin films of metal oxides grown on metal single crystal surfaces using Scanning Tunneling Microscopy (STM) are presented. The oxide overlayer systems studied are iron oxide and titanium oxide on the Pt(III) surface. The complexity of the metal oxides and large lattice mismatches often lead to surface structures with large unit cells. These are particularly suited to a local real space technique such as scanning tunneling microscopy. In particular, the symmetry that is directly observed with the STM elucidates the relationship of the oxide overlayers to the substrate as well as distinguishing, the structures of different oxides.

  17. Laser transfer of diamond nanopowder induced by metal film blistering

    Science.gov (United States)

    Kononenko, T. V.; Alloncle, P.; Konov, V. I.; Sentis, M.

    2009-03-01

    Blister-based laser induced forward transfer (BB-LIFT) is a promising technique to produce surface microstructures of various advanced materials including inorganic and organic micro/nanopowders, suspensions and biological micro-objects embedded in life sustaining medium. The transferred material is spread over a thin metal film irradiated from the far side by single laser pulses through a transparent support. Interaction of the laser pulse with the metal-support interface under optimized conditions causes formation of a quickly expanding blister. Fast movement of the free metal surface provides efficient material transfer, which has been investigated for the case of diamond nanopowder and diamond-containing suspension. The unique features of the given technique are universality, simplicity and efficient isolation of the transferred material from the ablation products and laser heating.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-06

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

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

    Science.gov (United States)

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

    2014-09-01

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

  20. Characterization of nano-scale protective oxide films: application on metal chemical mechanical planarization

    OpenAIRE

    Karagöz, Ayşe; Craciun, V.; Başım, Gül Bahar

    2015-01-01

    This study focuses on the characterization of nano-scale metal oxide films for chemical mechanical planarization (CMP) applications. The protective nature of the self-grown metal oxide layers in the CMP slurry environment enable topographic selectivity required for metallization of interconnects. Tungsten was selected as the model metal film to study the formation and characteristics of the metal oxide nano-layers since tungsten CMP is very well-established in conventional semiconductor manuf...

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

    Indian Academy of Sciences (India)

    Manika Khanuja; B R Mehta; S M Shivaprasad

    2008-11-01

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

  2. Continuous Preparation of Copper/Carbon Nanotube Composite Films and Application in Solar Cells.

    Science.gov (United States)

    Luo, Xiao Gang; Le Wu, Min; Wang, Xiao Xia; Zhong, Xin Hua; Zhao, Ke; Wang, Jian Nong

    2016-02-08

    Realizing the continuous and large scale preparation of particle/carbon nanotube (CNT) composites with enhanced functionalities, and broad applications in energy conversion, harvesting, and storage systems, remains as a big challenge. Here, we report a scalable strategy to continuously prepare particle/CNT composite films in which particles are confined by CNT films. This is achieved by the continuous condensation and deposition of a cylindrical assembly of CNTs on a paper strip and the in situ incorporation of particles during the layer-by-layer deposition process. A Cu/CNT composite film is prepared as an example; such a film exhibits very high power conversion efficiency when it is used as a counter electrode in a solar cell, compared with previous materials under otherwise identical conditions. The proposed method can be extended to other CNT-based composite films with excellent functionalities for wide applications.

  3. Solution processed metal oxide thin film hole transport layers for high performance organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Steirer, K. Xerxes; Berry, Joseph J.; Chesin, Jordan P.; Lloyd, Matthew T.; Widjonarko, Nicodemus Edwin; Miedaner, Alexander; Curtis, Calvin J.; Ginley, David S.; Olson, Dana C.

    2017-01-10

    A method for the application of solution processed metal oxide hole transport layers in organic photovoltaic devices and related organic electronics devices is disclosed. The metal oxide may be derived from a metal-organic precursor enabling solution processing of an amorphous, p-type metal oxide. An organic photovoltaic device having solution processed, metal oxide, thin-film hole transport layer.

  4. Thin metal film-polymer composite for efficient optoacoustic generation (Conference Presentation)

    Science.gov (United States)

    Lee, Taehwa; Guo, L. Jay

    2016-03-01

    Photoacoustic (PA) conversion of metal film absorbers is known to be inefficient because of their low thermal expansion and high light reflectance, as compared to polymeric materials containing light absorbing fillers. Specifically, the PA signal for metal films is typically an order of magnitude lower than those for PDMS-based composites consisting of carbon materials such as carbon blacks, carbon nanotubes, and carbon fibers. However, the carbon-PDMS composites have several disadvantages, e.g., difficulty in controlling film thickness, aggregation of the carbon fillers, and poor patternablility. To overcome these issues and achieve comparable PA amplitudes, a polymer-metal film composite was developed consisting of a thin metal absorber and adjacent transparent polymer layers. The proposed structure shows efficient PA conversion. The measured PA amplitude of the metal film composite is an order of magnitude higher than that of metal-only samples, and comparable to those of the carbon-PDMS composites. The enhanced PA conversion is accomplished by using metal film of a few tens of nanometers, which greatly facilitates heat transfer from the metal film to the surrounding polymers. Moreover, integrating the metal film composite with a photonic cavity can compensate light absorption loss of the thinner metal film. Theoretical and experimental analysis is conducted for understanding the mechanism behind such improvement. This strategy could be implemented for spatial PA signal patterns, especially for deep tissue PA imaging of implants or image-guiding tools. Furthermore, this approach also provides a guideline for designing photoacoustic transmitters and contrast agents.

  5. Stable metal-insulator transition in epitaxial SmNiO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Sieu D., E-mail: sdha@seas.harvard.edu [School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 (United States); Otaki, Miho; Jaramillo, R.; Podpirka, Adrian; Ramanathan, Shriram [School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138 (United States)

    2012-06-15

    Samarium nickelate (SmNiO{sub 3}) is a correlated oxide that exhibits a metal-insulator transition (MIT) above room temperature and is of interest for advanced electronics and optoelectronics. However, studies on SmNiO{sub 3} thin films have been limited to date, in part due to well-known difficulties in stabilizing the Ni{sup 3+} valence state during growth, which are manifested in non-reproducible electrical characteristics. In this work, we show that stable epitaxial SmNiO{sub 3} thin films can be grown by rf magnetron sputtering without extreme post-deposition annealing conditions using relatively high growth pressure (>200 mTorr). At low growth pressure, SmNiO{sub 3} is insulating and undergoes an irreversible MIT at {approx}430 K. As pressure is increased, films become metallic across a large temperature range from 100 to 420 K. At high pressure, films are insulating again but with a reversible and stable MIT at {approx}400 K. Phase transition properties can be continuously tuned by control of the sputtering pressure. - Graphical Abstract: X-ray diffraction (left) and resistivity-temperature characteristics (right) of sputtered SmNiO{sub 3} thin films as a function of sputtering pressure. As sputtering pressure increases, the out-of-plane lattice constant of SmNiO{sub 3} decreases, consistent with enhanced oxygen concentration. Concordantly, the electrical properties are strongly modified, and a reversible metal-insulator phase transition is observed at {approx}400 K in the film grown at high pressure. Highlights: Black-Right-Pointing-Pointer Stable SmNiO{sub 3} films grown by rf sputtering without extreme annealing conditions. Black-Right-Pointing-Pointer High sputtering pressures needed to fully stabilize SmNiO{sub 3}. Black-Right-Pointing-Pointer Reversible metal-insulator transition observed at {approx}400 K, similar to bulk. Black-Right-Pointing-Pointer Electrical properties strongly modifiable by varying sputtering pressure.

  6. Thin films of metal-organic compounds and metal nanoparticle-embedded polymers for nonlinear optical applications

    Indian Academy of Sciences (India)

    S Philip Anthony; Shatabdi Porel; D Narayana Rao; T P Radhakrishnan

    2005-11-01

    Thin films based on two very different metal-organic systems are developed and some nonlinear optical applications are explored. A family of zinc complexes which form perfectly polar assemblies in their crystalline state are found to organize as uniaxially oriented crystallites in vapor deposited thin films on glass substrate. Optical second harmonic generation from these films is investigated. A simple protocol is developed for the in-situ fabrication of highly monodisperse silver nanoparticles in a polymer film matrix. The methodology can be used to produce free-standing films. Optical limiting capability of the nanoparticle-embedded polymer film is demonstrated.

  7. Gold film-catalysed benzannulation by Microwave-Assisted, Continuous Flow Organic Synthesis (MACOS

    Directory of Open Access Journals (Sweden)

    Gjergji Shore

    2009-07-01

    Full Text Available Methodology has been developed for laying down a thin gold-on-silver film on the inner surface of glass capillaries for the purpose of catalysing benzannulation reactions. The cycloaddition precursors are flowed through these capillaries while the metal film is being heated to high temperatures using microwave irradiation. The transformation can be optimized rapidly, tolerates a wide number of functional groups, is highly regioselective, and proceeds in good to excellent conversion.

  8. Preparation of Mesoporous Silica Templated Metal Nanowire Films on Foamed Nickel Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Roger [University of Alabama, Tuscaloosa; Kenik, Edward A [ORNL; Bakker, Martin [University of Alabama, Tuscaloosa; Havrilla, George [Los Alamos National Laboratory (LANL); Montoya, Velma [Los Alamos National Laboratory (LANL); Shamsuzzoha, Mohammed [University of Alabama, Tuscaloosa

    2006-01-01

    A method has been developed for the formation of high surface area nanowire films on planar and three-dimensional metal electrodes. These nanowire films are formed via electrodeposition into a mesoporous silica film. The mesoporous silica films are formed by a sol-gel process using Pluronic tri-block copolymers to template mesopore formation on both planar and three-dimensional metal electrodes. Surface area increases of up to 120-fold have been observed in electrodes containing a templated film when compared to the same types of electrodes without the templated film.

  9. Tactile Sensing From Laser-Ablated Metallized PET Films

    KAUST Repository

    Nag, Anindya

    2016-10-17

    This paper reports the design, fabrication, and implementation of a novel sensor patch developed from commercial polyethylene terephthalate films metallized with aluminum on one side. The aluminum was ablated with laser to form interdigitated electrodes to make sensor prototypes. The interdigitated electrodes were patterned on the substrate with a laser cutter. Characterization of the prototypes was done to determine their operating frequency followed by experimentation. The prototypes have been used as a tactile sensor showing promising results for using these patches in applications with contact pressures considerably lesser than normal human contact pressure.

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

    Science.gov (United States)

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

    2005-12-01

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

  11. Effect of film thickness on optical constants of metal film%膜层厚度对金属薄膜光学常数的影响

    Institute of Scientific and Technical Information of China (English)

    卢进军; 李向阳; 孙雪平

    2012-01-01

    The theoretical basis that the thickness has an effect on the optical constants n, k of the ultra-thin metal film is obtained based on the Maxwell's equations. Different thickness of Cu film, Cr film and Ag film with the methods of resistance thermal evaporation and electron beam heating are deposited on the K9 glass substrates. The samples are detected by ellipsometry and simulated by Drude model. Therefore, the change rules that the optical constant n, k of the three films change with the wavelength A is gained. The optical constants between ultra-thin metal films and bulk metal films vary widely and with the increase of the thickness of the film the value of n, k is close to bulk metal's. Absorption and dispersion analysis shows that in the visible band the continuous metal film has a high absorption of the long-wave and the average dispersion rate is higher in 10nm~102nm orders of magnitude than the dielectric thin films.%从麦克斯韦方程出发,可以得到超薄金属膜层光学常数n、k与其厚度有关系的理论依据.采用电阻热蒸发和电子束热蒸发的方法在K9玻委基底上分别沉积了不同厚度的Cu膜、Cr膜、Ag膜,由椭偏法检测、Drude模型拟合,获得了不同厚度Cu膜、Cr膜、Ag膜光学常数n、k随波长λ的变化规律.超薄金属薄膜与块状金属的光学常数相差较大,随着薄膜厚度的增加,n、k值趋近于块状金属.通过对样品膜层吸收、色散特性的分析,发现连续金属薄膜在可见光波段对长波的吸收较大,而且相比于介质薄膜平均色散率高10mn~102 nm量级.

  12. Size Dependence of the Melting Temperature of Metallic Films: Two Possible Scenarios

    Directory of Open Access Journals (Sweden)

    V.M. Samsonov

    2013-11-01

    Full Text Available The size dependence was investigated of the melting temperature Tm of metallic films (tin and copper on different substrate (amorphous carbon, another infusible metal, i.e. the dependence of Tm on the film thickness h. It was found that the effect of interfacial boundary can result in the growth of Tm for thin metallic films on the carbon substrate in comparison with the corresponding bulk value. For the metal 1 / metal 2 system the size dependence of Tm seems to be less pronounced and Tm decreases with decreasing thickness h.

  13. Continuous Preparation of Carbon Nanotube Film and Its Applications in Fuel and Solar Cells.

    Science.gov (United States)

    Luo, Xiao Gang; Huang, Xin Xin; Wang, Xiao Xia; Zhong, Xin Hua; Meng, Xin Xin; Wang, Jian Nong

    2016-03-01

    So far, simultaneously realizing the continuous, controllable, and scalable preparation of carbon nanotube (CNT) film has remained a big challenge. Here, we report a scalable approach to continuously prepare CNT film with good control of film size and thickness. This is achieved through the layer-by-layer condensation and deposition of a cylindrical CNT assembly that is continuously produced from a floating catalyst CVD reactor on a paper strip. The promising applications of such a film are demonstrated by directly using it as an effective protecting layer for the Pt/C catalyst in proton exchange membrane fuel cells and as an efficient counter electrode material in quantum-dot-sensitized solar cells.

  14. Mechanical properties of thin film Parylene-metal-Parylene devices

    Directory of Open Access Journals (Sweden)

    Curtis Dixon Lee

    2015-09-01

    Full Text Available Structures and testing methods for measuring the adhesion strength, minimum bending diameter, and bending fatigue performance of thin film polymer electronic architectures were developed and applied to Parylene-metal-Parylene systems with and without the moisture barrier Al2O3 (deposited using atomic layer deposition (ALD. Parylene-metal-Parylene interfaces had the strongest average peel test strength and Parylene-Parylene interfaces had the weakest peel. Layers of ALD Al2O3 deposited within the device increased the average peel strength for Parylene-Parylene interfaces when combined with silane A-174, but did not increase the Parylene-metal-Parylene interface. Metal traces in the middle of 24 µm thick Parylene-metal-Parylene devices had a minimum bending diameter of ~130 µm before breaking and being measured as an open circuit. The addition of one layer of Al2O3 above the traces allowed them to be completely creased when bent away from the Al2O3 layer without producing an open circuit, but increased the minimum bending diameter to ~450 µm when bent away from the Al2O3. Although fatigue testing produced cracks in all devcies after 100k bends, the insulation of the Parylene-metal-Parylene devices without Al2O3 performed well with electrochemical impedance spectroscopy (EIS showing only small decreases in impedance magnitude and small increases of impedance phase at low frequencies. However, devices with Al2O3 failed during EIS due to Al2O3 being deteriorated by water.

  15. Atomic layer deposition of metal sulfide thin films using non-halogenated precursors

    Energy Technology Data Exchange (ETDEWEB)

    Martinson, Alex B. F.; Elam, Jeffrey W.; Pellin, Michael J.

    2015-05-26

    A method for preparing a metal sulfide thin film using ALD and structures incorporating the metal sulfide thin film. The method includes providing an ALD reactor, a substrate, a first precursor comprising a metal and a second precursor comprising a sulfur compound. The first and the second precursors are reacted in the ALD precursor to form a metal sulfide thin film on the substrate. In a particular embodiment, the metal compound comprises Bis(N,N'-di-sec-butylacetamidinato)dicopper(I) and the sulfur compound comprises hydrogen sulfide (H.sub.2S) to prepare a Cu.sub.2S film. The resulting metal sulfide thin film may be used in among other devices, photovoltaic devices, including interdigitated photovoltaic devices that may use relatively abundant materials for electrical energy production.

  16. Dynamic strain in metallic vs insulating manganite films

    Energy Technology Data Exchange (ETDEWEB)

    Dekker, Martina Cornelia; Oswald, Steffen; Schultz, Ludwig; Doerr, Kathrin [IFW Dresden (Germany)

    2008-07-01

    The use of a ferro- and piezoelectric substrate, PMN-PT(001) (PbMg{sub 1/3}Nb{sub 2/3}O{sub 3}){sub 0.72}(PbTiO{sub 3}){sub 0.28}, allows us to biaxially compress as grown epitaxial films by as much as 0.2%. This reversible dynamic strain process gives a unique insight into the effect of strain on perovskite oxides, eliminating effects such as varying oxygen concentration, which may occur when several substrates with different lattice mismatch are used. We have prepared PLCMO (Pr{sub 1-x}La{sub x}){sub 0.7}Ca{sub 0.3}MnO{sub 3} films on PMN-PT substrates for a range of x values. Around x=0.6, the system exhibits a transition from an insulating to a metallic ground state. We have recorded changes in magnetic moment and transition temperature upon varying x, and compared the effects of dynamic strain on transport behaviour in the metallic and insulating ground states.

  17. Ferromagnetism and temperature-dependent electronic structure in metallic films

    CERN Document Server

    Herrmann, T

    1999-01-01

    reduced at the surface compared to the inner layers. This observation clearly contradicts the well-known Stoner picture of band magnetism and can be explained in terms of general arguments which are based on exact results in the limit of strong Coulomb interaction. The magnetic behavior of the Hubbard films can be analyzed in detail by inspecting the local quasi particle density of states as well as the wave vector dependent spectral density. The electronic structure is found to be strongly spin-, layer-, and temperature-dependent. The last part of this work is concerned about the temperature-driven reorientation transition in thin metallic films. For the description of the magnetic anisotropy in thin films the dipole interaction as well as the spin-orbit interaction have to be included in the model. By calculating the temperature-dependence of the magnetic anisotropy energy it is found that both types of temperature-driven reorientation transitions, from out-of-plane to in-plane (''Fe-type'') and from in-pla...

  18. Controlled Mechanical Cracking of Metal Films Deposited on Polydimethylsiloxane (PDMS

    Directory of Open Access Journals (Sweden)

    Andreas Polywka

    2016-09-01

    Full Text Available Stretchable large area electronics conform to arbitrarily-shaped 3D surfaces and enables comfortable contact to the human skin and other biological tissue. There are approaches allowing for large area thin films to be stretched by tens of percent without cracking. The approach presented here does not prevent cracking, rather it aims to precisely control the crack positions and their orientation. For this purpose, the polydimethylsiloxane (PDMS is hardened by exposure to ultraviolet radiation (172 nm through an exposure mask. Only well-defined patterns are kept untreated. With these soft islands cracks at the hardened surface can be controlled in terms of starting position, direction and end position. This approach is first investigated at the hardened PDMS surface itself. It is then applied to conductive silver films deposited from the liquid phase. It is found that statistical (uncontrolled cracking of the silver films can be avoided at strain below 35%. This enables metal interconnects to be integrated into stretchable networks. The combination of controlled cracks with wrinkling enables interconnects that are stretchable in arbitrary and changing directions. The deposition and patterning does not involve vacuum processing, photolithography, or solvents.

  19. Electron confinement in thin metal films. Structure, morphology and interactions

    Energy Technology Data Exchange (ETDEWEB)

    Dil, J.H.

    2006-05-15

    This thesis investigates the interplay between reduced dimensionality, electronic structure, and interface effects in ultrathin metal layers (Pb, In, Al) on a variety of substrates (Si, Cu, graphite). These layers can be grown with such a perfection that electron confinement in the direction normal to the film leads to the occurrence of quantum well states in their valence bands. These quantum well states are studied in detail, and their behaviour with film thickness, on different substrates, and other parameters of growth are used here to characterise a variety of physical properties of such nanoscale systems. The sections of the thesis deal with a determination of quantum well state energies for a large data set on different systems, the interplay between film morphology and electronic structure, and the influence of substrate electronic structure on their band shape; finally, new ground is broken by demonstrating electron localization and correlation effects, and the possibility to measure the influence of electron-phonon coupling in bulk bands. (orig.)

  20. Infrared spectroscopy of thin organic films on metal surfaces

    Science.gov (United States)

    Boerio, F. J.; Boerio, J. P.; Bozian, R. C.

    1988-01-01

    The principles of external reflection infrared spectroscopy for obtaining spectra of thin films on surfaces by reflecting infrared radiation from the surface at large, almost grazing angles, were reviewed and new applications were described. Infrared spectra of monomolecular films formed by myristic acid adsorbed from dilute solutions in nitrobenzene onto aluminum and chromium were obtained. Adsorption onto both substrates involved dissociation of the acid groups to form carboxylate species but undissociated monomer was retained in the films formed on aluminum. Myristic acid was adsorbed onto aluminum with a vertical conformation in which the twofold symmetry axes of the carboxylate groups were nearly perpendicular to the surface of the substrate. The twofold axes of the carboxylate groups were more inclined with respect to the normal to the surface for the chromium substrates. Terephthalic acid and terephthalic acid-d 4 were adsorbed onto aluminum from dilute solutions in ethanol with a vertical conformation in which one acid group was dissociated to form a salt with a metal ion in the substrate while the other acid group may have formed hydrogen bonds with neighboring molecules. When thin films of ethylene/vinyl acetate copolymers were applied to the aluminized back sides of silicon solar cells which were then immersed in boiling water for a few minutes, the hydrated oxide pseudoboehmite rapidly formed at the interface. A primer containing γ-methacryoxypropyltrimethoxysilane (γ-MPS) inhibited the formation of pseudoboehmite from the rough aluminized back sides of crystalline silicon cells but not from the smooth aluminized back sides of amorphous cells.

  1. Preparation and adsorption properties of nano magnetite chitosan films for heavy metal ions from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Lasheen, M.R., E-mail: ragaei24@link.net [Water Pollution Research Department, Environmental Research Division, National Research Centre, 33-El Buhoth St., Dokki, Cairo, 12311 (Egypt); El-Sherif, Iman Y., E-mail: iman57us@yahoo.com [Water Pollution Research Department, Environmental Research Division, National Research Centre, 33-El Buhoth St., Dokki, Cairo, 12311 (Egypt); Tawfik, Magda E., E-mail: magdaemileta@yahoo.com [Polymers and Pigments Department, National Research Centre, 33-El Buhoth St., Dokki, Cairo, 12311 (Egypt); El-Wakeel, S.T., E-mail: shaimaa_tw@yahoo.com [Water Pollution Research Department, Environmental Research Division, National Research Centre, 33-El Buhoth St., Dokki, Cairo, 12311 (Egypt); El-Shahat, M.F., E-mail: elshahatmf@hotmail.com [Faculty of Science, Ain Shams University, Khalifa El-Maamon St., Abbasiya Sq., 11566, Cairo (Egypt)

    2016-08-15

    Highlights: • Nano magnetite–chitosan films were prepared by casting method. • The efficiency of the prepared films for removing heavy metals was investigated. • The adsorption mechanism was studied using different isotherm and kinetic models. • Films reuse and metals recovery were studied. - Abstract: Nano magnetite chitosan (NMag–CS) film was prepared and characterized with different analytical methods. X-ray diffraction (XRD) patterns confirmed the formation of a pure magnetite structure and NMag–CS nanocomposite. TEM image of the film, revealed the uniform dispersion of magnetite nanoparticles inside chitosan matrix. The adsorption properties of the prepared film for copper, lead, cadmium, chromium and nickel metal ions were evaluated. Different factors affecting the uptake behavior by the composite films such as time, initial pH and film dose were investigated. The adsorption equilibrium attained using 2 g/L of the film after 120 min of reaction. The equilibrium data were analyzed using Langmuir and Freundlich models. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all metals. The metals regenerated from films with an efficiency greater than 95% using 0.1 M ethylene diamine tetra acetic acid (EDTA) and films were successfully reused for adsorption.

  2. Characteristic comparison of metal films coated onto the cenosphere by chemical and magnetron sputtering methods

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Metal-coated cenospheres have been widely used in Industries. Different coating methods result in different characteristic metal films. Hie metal film on the cenosphere by chemical coating does not appear to be very smooth, exhibiting metal piled up and pin holes on the surface and leaving some spots uncoated. Meanwhile, the metal film is not tightly absorbed onto cenospheres and is easy to peel off. However, the metal film prepared by magnetron sputtering is compact, smooth and without pin holes. The film has good affinity to the cenosphere surface. Such films do not separate with it even when the cenosphere is crushed. Both the metal films give the same XRD patterns, indicating tnat the crystal structure of the metal films by these two methods is the same. Chemical coating is a complex process and harmful to the environment, but it fits ultrafine powder coating (the particle size can be less than 2 μm). The magnetron sputtering method is environmental friendly and works quickly, but this method requires specially designed equipment and does not work for ultrafine powders. If the particle size is less than 30 μm, the coating process is hard to carry on.

  3. Simple Methods for Production of Nanoscale Metal Oxide Films from Household Sources

    Science.gov (United States)

    Campbell, Dean J.; Baliss, Michelle S.; Hinman, Jordan J.; Ziegenhorn, John W.; Andrews, Mark J.; Stevenson, Keith J.

    2013-01-01

    Production of thin metal oxide films was recently explored as part of an outreach program with a goal of producing nanoscale structures with household items. Household items coated with various metals or titanium compounds can be heated to produce colorful films with nanoscale thicknesses. As part of a materials chemistry laboratory experiment…

  4. Transition metal oxide thin films for nonvolatile resistive random access memory applications

    National Research Council Canada - National Science Library

    BAO, Dinghua

    2009-01-01

    .... This paper briefly reviews the status and new progress on binary transition metal oxide thin film materials such as NiO, TiO2, ZrO2, ZnO, and their multilayered thin films and metal nanocomposite...

  5. Filmes de metal-hexacianoferrato: uma ferramenta em química analítica Metal-hexacyanoferrate films: a tool in analytical Chemistry

    Directory of Open Access Journals (Sweden)

    Ivanildo Luiz de Mattos

    2001-04-01

    Full Text Available Chemically modified electrodes based on hexacyanometalate films are presented as a tool in analytical chemistry. Use of amperometric sensors and/or biosensors based on the metal-hexacyanoferrate films is a tendency. This article reviews some applications of these films for analytical determination of both inorganic (e.g. As3+, S2O3(2- and organic (e.g. cysteine, hydrazine, ascorbic acid, gluthatione, glucose, etc. compounds.

  6. Terahertz transport dynamics in the metal-insulator transition of V2O3 thin film

    Science.gov (United States)

    Luo, Y. Y.; Su, F. H.; Zhang, C.; Zhong, L.; Pan, S. S.; Xu, S. C.; Wang, H.; Dai, J. M.; Li, G. H.

    2017-03-01

    The dynamic behavior of thermally-induced metal-insulator transition of V2O3 thin film on Si substrate grown by reactive magnetron sputtering was investigated by the terahertz time-domain spectroscopy. It was found that the THz absorption and optical conductivity of the thin films are temperature-dependent, and the THz amplitude modulation can reach as high as 74.7%. The complex THz optical conductivity in the metallic state of the V2O3 thin films can be well-fitted by the Drude-Smith model, which offer the insight into the electron transport dynamic during the metal-insulator transition of the thin film.

  7. Metal Organic Chemical Vapour Deposited Thin Films of Cobalt Oxide Prepared via Cobalt Acetylacetonate

    Institute of Scientific and Technical Information of China (English)

    C.U. Mordi; M.A. Eleruja; B.A. Taleatu; G.O. Egharevba; A.V. Adedeji; 0.0. Akinwunmi; B. Olofinjana; C. Jeynes; E.O.B. Ajayi

    2009-01-01

    The single solid source precursor, cobalt (Ⅱ) acetylacetonate was prepared and characterized by infrared spec-troscopy. Thin films of cobalt oxide were deposited on soda lime glass substrates through the pyrolysis (metal organic chemical vapour deposition (MOCVD)) of single solid source precursor, cobalt acetylaceto-nate, Co[C5H7O2]2 at a temperature of 420℃. The compositional characterization carried out by rutherford backscattering spectroscopy and X-ray diffraction (XRD), showed that the films have a stoichiometry of Co2O3 and an average thickness of 227±0.2 nm. A direct energy gap of 2.15±0.01 eV was calculated by the data obtained by optical absorption spectroscopy. The morphology of the films obtained by scanning electron mi-croscopy, showed that the grains were continuous and uniformly distributed at various magnifications, while the average grain size was less than 1 micron for the deposited thin films of cobalt oxide.

  8. Observation and Mediation of the Presence of Metallic Lead in Organic-Inorganic Perovskite Films.

    Science.gov (United States)

    Sadoughi, Golnaz; Starr, David E; Handick, Evelyn; Stranks, Samuel D; Gorgoi, Mihaela; Wilks, Regan G; Bär, Marcus; Snaith, Henry J

    2015-06-24

    We have employed soft and hard X-ray photoelectron spectroscopies to study the depth-dependent chemical composition of mixed-halide perovskite thin films used in high-performance solar cells. We detect substantial amounts of metallic lead in the perovskite films, which correlate with significant density of states above the valence band maximum. The metallic lead content is higher in the bulk of the perovskite films than at the surface. Using an optimized postanneal process in air, we can reduce the metallic lead content in the perovskite film. This process reduces the amount of metallic lead and a corresponding increase in the photoluminescence quantum efficiency of the perovskite films can be observed. This correlation indicates that metallic lead impurities are likely a key defect whose concentration can be controlled by simple annealing procedures in order to increase the performance for perovskite solar cells.

  9. Structural Characterization of Carbon Nanomaterial Film In Situ Synthesized on Various Bulk Metals

    Directory of Open Access Journals (Sweden)

    J. Y. Xu

    2014-01-01

    Full Text Available Carbon nanofiber films were prepared via a simple chemical vapor deposition (CVD method on various bulk metal substrates including bulk 316 L stainless steel, pure cobalt, and pure nickel treated by surface mechanical attrition treatment (SMAT. The microstructures of the carbon nanomaterial film were studied by SEM, TEM, XRD, and Raman spectroscopy. In this paper, bulk metallic materials treated by SMAT served as substrates as well as catalysts for carbon nanomaterial film formation. The results indicate that the carbon nanofiber films are formed concerning the catalytic effects of the refined metallic particles during CVD on the surface of SMAT-treated bulk metal substrates. However, distinguished morphologies of carbon nanomaterial film are displayed in the case of the diverse bulk metal substrates.

  10. Metal thin film growth on multimetallic surfaces: From quaternary metallic glass to binary crystal

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Dapeng [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    The work presented in this thesis mainly focuses on the nucleation and growth of metal thin films on multimetallic surfaces. First, we have investigated the Ag film growth on a bulk metallic glass surface. Next, we have examined the coarsening and decay of bilayer Ag islands on NiAl(110) surface. Third, we have investigated the Ag film growth on NiAl(110) surface using low-energy electron diffraction (LEED). At last, we have reported our investigation on the epitaxial growth of Ni on NiAl(110) surface. Some general conclusions can be drawn as follows. First, Ag, a bulk-crystalline material, initially forms a disordered wetting layer up to 4-5 monolayers on Zr-Ni-Cu-Al metallic glass. Above this coverage, crystalline 3D clusters grow, in parallel with the flatter regions. The cluster density increases with decreasing temperature, indicating that the conditions of island nucleation are far-from-equilibrium. Within a simple model where clusters nucleate whenever two mobile Ag adatoms meet, the temperature-dependence of cluster density yields a (reasonable) upper limit for the value of the Ag diffusion barrier on top of the Ag wetting layer of 0.32 eV. Overall, this prototypical study suggests that it is possible to grow films of a bulk-crystalline metal that adopt the amorphous character of a glassy metal substrate, if film thickness is sufficiently low. Next, the first study of coarsening and decay of bilayer islands has been presented. The system was Ag on NiAl(110) in the temperature range from 185 K to 250 K. The coarsening behavior, has some similarities to that seen in the Ag(110) homoepitaxial system studied by Morgenstern and co-workers. At 185 K and 205 K, coarsening of Ag islands follows a Smoluchowski ripening pathway. At 205 K and 250 K, the terrace diffusion limited Ostwald ripening dominants. The experimental observed temperature for the transition from SR to OR is 205 K. The SR exhibits anisotropic island diffusion and the OR exhibits 1D decay of island

  11. Metal oxide semiconductor thin-film transistors for flexible electronics

    Science.gov (United States)

    Petti, Luisa; Münzenrieder, Niko; Vogt, Christian; Faber, Hendrik; Büthe, Lars; Cantarella, Giuseppe; Bottacchi, Francesca; Anthopoulos, Thomas D.; Tröster, Gerhard

    2016-06-01

    The field of flexible electronics has rapidly expanded over the last decades, pioneering novel applications, such as wearable and textile integrated devices, seamless and embedded patch-like systems, soft electronic skins, as well as imperceptible and transient implants. The possibility to revolutionize our daily life with such disruptive appliances has fueled the quest for electronic devices which yield good electrical and mechanical performance and are at the same time light-weight, transparent, conformable, stretchable, and even biodegradable. Flexible metal oxide semiconductor thin-film transistors (TFTs) can fulfill all these requirements and are therefore considered the most promising technology for tomorrow's electronics. This review reflects the establishment of flexible metal oxide semiconductor TFTs, from the development of single devices, large-area circuits, up to entirely integrated systems. First, an introduction on metal oxide semiconductor TFTs is given, where the history of the field is revisited, the TFT configurations and operating principles are presented, and the main issues and technological challenges faced in the area are analyzed. Then, the recent advances achieved for flexible n-type metal oxide semiconductor TFTs manufactured by physical vapor deposition methods and solution-processing techniques are summarized. In particular, the ability of flexible metal oxide semiconductor TFTs to combine low temperature fabrication, high carrier mobility, large frequency operation, extreme mechanical bendability, together with transparency, conformability, stretchability, and water dissolubility is shown. Afterward, a detailed analysis of the most promising metal oxide semiconducting materials developed to realize the state-of-the-art flexible p-type TFTs is given. Next, the recent progresses obtained for flexible metal oxide semiconductor-based electronic circuits, realized with both unipolar and complementary technology, are reported. In particular

  12. Nanopatterned Metallic Films for Use As Transparent Conductive Electrodes in Optoelectronic Devices

    KAUST Repository

    Catrysse, Peter B.

    2010-08-11

    We investigate the use of nanopatterned metallic films as transparent conductive electrodes in optoelectronic devices. We find that the physics of nanopatterned electrodes, which are often optically thin metallic films, differs from that of optically thick metallic films. We analyze the optical properties when performing a geometrical transformation that maintains the electrical properties. For one-dimensional patterns of metallic wires, the analysis favors tall and narrow wires. Our design principles remain valid for oblique incidence and readily carry over to two-dimensional patterns. © 2010 American Chemical Society.

  13. Effect of temperature on the stability of diamond particles and continuous thin films by Raman imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kumaran, C. R.; Tiwari, Brajesh; Chandran, Maneesh; Bhattacharya, S. S.; Ramachandra Rao, M. S., E-mail: msrrao@iitm.ac.in [Indian Institute of Technology Madras, Nano Functional Materials Technology Centre (India)

    2013-03-15

    The stability of diamond thin films grown by hot filament CVD (HFCVD) upon thermal treatment was studied using Raman imaging. By adapting two different surface pretreatments, continuous microcrystalline diamond (MCD) thin films (grain size: 100-400 nm; cross-sectional thickness: {approx}300 nm) as well as thin film with isolated and coalesced diamond particles (particle size: 400-600 nm; cross-sectional thickness: {approx}200-300 nm) were grown. The thermal stability of isolated diamond particles and continuous MCD films annealed in air at atmospheric pressure was analyzed by Raman imaging. For Raman imaging, Raman spectra were collected over an area of 85 Multiplication-Sign 85 {mu}m using 532 nm laser (Nd:YAG) before and after thermal treatment. It was observed that the isolated diamond particles were stable for 1 h at {approx}750 Degree-Sign C, whereas for the same annealing duration, continuous MCD films grown under the same HFCVD condition were completely oxidized at 700 Degree-Sign C. From these results and analysis, the reason for the higher oxidation rates in the case of MCD and nanocrystalline diamond films is discussed.

  14. Volmer-Weber growth stages of polycrystalline metal films probed by in situ and real-time optical diagnostics

    Science.gov (United States)

    Abadias, G.; Simonot, L.; Colin, J. J.; Michel, A.; Camelio, S.; Babonneau, D.

    2015-11-01

    The Volmer-Weber growth of high-mobility metal films is associated with the development of a complex compressive-tensile-compressive stress behavior as the film deposition proceeds through nucleation of islands, coalescence, and formation of a continuous layer. The tensile force maximum has been attributed to the end of the islands coalescence stage, based on ex situ morphological observations. However, microstructural rearrangements are likely to occur in such films during post-deposition, somewhat biasing interpretations solely based on ex situ analysis. Here, by combining two simultaneous in situ and real-time optical sensing techniques, based on surface differential reflectance spectroscopy (SDRS) and change in wafer curvature probed by multibeam optical stress sensor (MOSS), we provide direct evidence that film continuity does coincide with tensile stress maximum during sputter deposition of a series of metal (Ag, Au, and Pd) films on amorphous SiOx. Stress relaxation after growth interruption was testified from MOSS, whose magnitude scaled with adatom mobility, while no change in SDRS signal could be revealed, ruling out possible changes of the surface roughness at the micron scale.

  15. Design of Highly Sensitive Surface Plasmon Resonance Sensors Using Planar Metallic Films Closely Coupled to Nanogratings

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-Yan; XIE Wen-Chong; LIU De-Ming

    2008-01-01

    We investigate the sensitivity enhancement of surface plasmon resonance(SPR)sensors using planar metallic films closely coupled to nanogratings.The strong coupling between localized surface plasmon resonances(LSPRs)presenting in metallic nanostructures and surface plasmon polaritons(SPPs)propagating at the metallic film surface leads to changes of resonance reflection properties,resulting in enhanced sensitivity of SPR sensors.The effects of thickness of the metallic films,grating period and metal materials on the refractive index sensitivity of the device are investigated.The refractive index sensitivity of nanograting-based SPR sensors is predicted to be about 543 nm/RIU(refractive index unit)using optimized structure parameters.Our study on SPR sensors using planar metallic films closely coupled to nanogratings demonstrates the potential for significant improvement in refractive index sensitivity.

  16. 76 FR 13356 - Magnesium Metal From the People's Republic of China: Continuation of Antidumping Duty Order

    Science.gov (United States)

    2011-03-11

    ... International Trade Administration Magnesium Metal From the People's Republic of China: Continuation of... International Trade Commission (``ITC'') that revocation of the antidumping duty order on magnesium metal from... sunset reviews of the antidumping duty order on magnesium metal from the PRC, pursuant to section...

  17. 77 FR 23660 - Silicon Metal From the People's Republic of China: Continuation of Antidumping Duty Order

    Science.gov (United States)

    2012-04-20

    ... International Trade Administration Silicon Metal From the People's Republic of China: Continuation of... International Trade Commission (``ITC'') that revocation of the antidumping duty order on silicon metal from the... sunset review of the antidumping duty order on silicon metal from the PRC, pursuant to section 751(c)...

  18. Superconducting YBa 2Cu 3O 7- δ thin film grown on metallic film evaporated on MgO

    Science.gov (United States)

    Verdyan, A.; Azoulay, J.; Lapsker, I.

    2001-03-01

    At present it is commonly accepted that thin film formation of YBa 2Cu 3O 7- δ (YBCO) on conducting substrate is one of the keys to further development of advanced devices in the microelectronic and other applications. We have grown YBCO thin films by resistive evaporation technique on MgO coated with metallic layers (Ni or Ag). A simple inexpensive vacuum system equipped with resistively heated boats for metal and precursor mixture of yttrium, copper and barium fluoride powders was used. X-ray diffraction (XRD) and scanning electron microscopy techniques were used for texture, morphology and surface analyses respectively. Electrical and magnetical properties were determined by a standard dc four-probe method. The way of heating process is shown to be critical parameter in the film quality. The physical and electrical properties of the YBCO films are discussed in light of the fact that XRD measurements done on the metallic buffer layers have revealed a multicrystalline structure.

  19. Minimal model for optical transmission through holey metal films

    Energy Technology Data Exchange (ETDEWEB)

    MartIn-Moreno, L [Departamento de Fisica de la Materia Condensada-ICMA, Universidad de Zaragoza-CSIC, E-50009 Zaragoza (Spain); GarcIa-Vidal, F J [Departamento de Fisica Teorica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)], E-mail: lmm@unizar.es

    2008-07-30

    This paper presents a tutorial on the computation of both extraordinary optical transmission and surface electromagnetic modes in holey metal films. Our model consists of a square array of square holes in a perfect conductor. It is shown that considering just the fundamental waveguide mode inside the holes captures the main features of the optical transmission, which allows us to obtain quasi-analytical results. Extraordinary optical transmission is unambiguously linked to the presence of surface electromagnetic modes in the corrugated structure. The particular case of surface electromagnetic modes in a perfect conductor is analyzed, paying attention to different strategies for increasing their confinement to the surface. The use of the energy loss of a charged particle passing close to the surface as a spectroscopic tool for these surface modes is also discussed.

  20. Low-cost metal substrates for films with aligned grain structures

    Energy Technology Data Exchange (ETDEWEB)

    Norton, D.P.; Budai, J.D.; Goyal, A.; Lowndes, D.H.; Kroeger, D.M.; Christen, D.K.; Paranthaman, M.; Specht, E.D.

    1996-06-01

    Polycrystalline metal substrates that possess a significant amount of in-plane and out-of-plane crystallographic texture have recently been developed for high-temperature superconducting film applications. These substrates enable the virtual elimination of large angle grain boundaries in subsequent epitaxial films, having been successfully utilized in various oxide thin film architectures. This paper describes the characteristics of these substrates, and briefly discusses their potential applicability in polycrystalline thin-film photovoltaic applications.

  1. The role of inhibitors during electrodeposition of thin metallic films

    Science.gov (United States)

    Armstrong, M. J.

    1990-05-01

    The role of brightening agents during the deposition of thin metal films was analyzed. The model brightening system studied was copper deposition in the presence of benzotriazole (BTA). Emphasis was placed on the early stages of deposition. The development of microtopography was characterized with in situ scanning tunneling microscopy. Cuprous-BTA film formation was measured with impedance spectroscopy. Copper electrochemistry was measured with double-pulse potentiometry. The incorporation of BTA, including the effects of mass transport conditions, was studied with x ray photoelectron spectroscopy and secondary ion mass spectroscopy. A visual survey of deposits from 0.5 M CuSO4, 0.5 M H2SO4 indicated that brightening occurs when the concentration of BTA is greater than 100 microM and the current density is greater than 50 mA/sq cm. A passive layer was found to form during cathodic polarization of copper in 0.5 M CuSO4, 0.5 M H2SO4 with 100 and 200 microM BTA. Followingbreakdown of the passive layer, with increased polarization, the copper remains covered with a BTA film with a coverage following Langmuir adsorption kinetics. Benzotriazole was not incorporated into the copper deposits. The nucleation site density of Cu on Pt was only a function of overpotential irrespective of the BTA concentration. The presence of BTA increases the overpotential (resulting in an increase in nucleation rate) for a given current density which results in a decreased particle size. Benzotriazole altered the morphology of the deposited Cu. Deposits from BTA free electrolyte consisted of flat planes terminated with ledges with growth occurring at the ledges. Deposits from BTA containing electrolyte consisted of hemispheres with growth occurring uniformly on the surface.

  2. The role of inhibitors during electrodeposition of thin metallic films

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, M.J. (California Univ., Berkeley, CA (USA). Dept. of Chemical Engineering Lawrence Berkeley Lab., CA (USA))

    1990-05-01

    The role of brightening agents during the deposition of thin metal films was analyzed. The model brightening system studied was copper deposition in the presence of benzotriazole (BTA). Emphasis was placed on the early stages of deposition. The development of microtopography was characterized with in situ scanning tunneling microscopy. Cuprous-BTA film formation was measured with impedance spectroscopy. Copper electrochemistry was measured with double-pulse potentiometry. The incorporation of BTA, including the effects of mass transport conditions, was studied with x-ray photoelectron spectroscopy and secondary ion mass spectroscopy. A visual survey of deposits from 0.5 M CuSO{sub 4}, 0.5 M H{sub 2}SO{sub 4} indicated that brightening occurs when the concentration of BTA is greater than 100 {mu}M and the current density is greater than 50 mA/cm{sup 2}. A passive layer was found to form during cathodic polarization of copper in 0.5 M CuSO{sub 4}, 0.5 M H{sub 2}SO{sub 4} with 100 and 200 {mu}M BTA. Following breakdown of the passive layer, with increased polarization, the copper remains covered with a BTA film with a coverage following Langmuir adsorption kinetics. Benzotriazole was not incorporated into the copper deposits. The nucleation site density of Cu on Pt was only a function of overpotential irrespective of the BTA concentration. The presence of BTA increases the overpotential (resulting in an increase in nucleation rate) for a given current density which results in a decreased particle size. Benzotriazole altered the morphology of the deposited Cu. Deposits from BTA free electrolyte consisted of flat planes terminated with ledges with growth occurring at the ledges. Deposits from BTA containing electrolyte consisted of hemispheres with growth occurring uniformly on the surface.

  3. Soldering of Thin Film-Metallized Glass Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Hernandez, C.L.; Glass, S.J.

    1999-03-31

    The ability to produce reliable electrical and structural interconnections between glass and metals by soldering was investigated. Soldering generally requires premetallization of the glass. As a solderable surface finish over soda-lime-silicate glass, two thin films coatings, Cr-Pd-Au and NiCr-Sn, were evaluated. Solder nettability and joint strengths were determined. Test samples were processed with Sn60-Pb40 solder alloy at a reflow temperature of 210 C. Glass-to-cold rolled steel single lap samples yielded an average shear strength of 12 MPa. Solder fill was good. Control of the Au thickness was critical in minimizing the formation of AuSn{sub 4} intermetallic in the joint, with a resulting joint shear strength of 15 MPa. Similar glass-to-glass specimens with the Cr-Pd-Au finish failed at 16.5 MPa. The NiCr-Sn thin film gave even higher shear strengths of 20-22.5 MPa, with failures primarily in the glass.

  4. Metal-Oxide Film Conversions Involving Large Anions

    Energy Technology Data Exchange (ETDEWEB)

    Pretty, S.; Zhang, X.; Shoesmith, D.W.; Wren, J.C. [The University of Western Ontario, Chemistry Department, 1151 Richmond St., N6A 5B7, London, Ontario (Canada)

    2008-07-01

    The main objective of my research is to establish the mechanism and kinetics of metal-oxide film conversions involving large anions (I{sup -}, Br{sup -}, S{sup 2-}). Within a given group, the anions will provide insight on the effect of anion size on the film conversion, while comparison of Group 6 and Group 7 anions will provide insight on the effect of anion charge. This research has a range of industrial applications, for example, hazardous radioiodine can be immobilized by reaction with Ag to yield AgI. From the perspective of public safety, radioiodine is one of the most important fission products from the uranium fuel because of its large fuel inventory, high volatility, and radiological hazard. Additionally, because of its mobility, the gaseous iodine concentration is a critical parameter for safety assessment and post-accident management. A full kinetic analysis using electrochemical techniques has been performed on the conversion of Ag{sub 2}O to (1) AgI and (2) AgBr. (authors)

  5. Thin films of metal oxides grown by chemical vapor deposition from volatile transition metal and lanthanide metal complexes

    Science.gov (United States)

    Pollard, Kimberly Dona

    1998-08-01

    This thesis describes the synthesis and characterization of novel volatile metal-organic complexes for the chemical vapor deposition (CVD) of metal oxides. Monomeric tantalum complexes, lbrack Ta(OEt)sb4(beta-diketonate)) are prepared by the acid-base reaction of lbrack Tasb2(OEt)sb{10}rbrack with a beta-diketone, (RC(O)CHsb2C(O)Rsp' for R = CHsb3, Rsp' = CFsb3; R = Rsp'=C(CHsb3)sb3; R = Csb3Fsb7,\\ Rsp'=C(CHsb3)sb3;\\ R=Rsp'=CFsb3; and R = Rsp' = CHsb3). The products are characterized spectroscopically. Thermal CVD using these complexes as precursors gave good quality Tasb2Osb5 thin films which are characterized by XPS, SEM, electrical measurements, and XRD. Factors affecting the film deposition such as the type of carrier gas and the temperature of the substrate were considered. Catalyst-enhanced CVD reactions with each of the precursors and a palladium catalyst, ((2-methylallyl)Pd(acac)), were studied as a lower temperature route to good quality Tasb2Osb5 films. The decomposition mechanism at the hot substrate surface was studied. Precursors for the formation of yttria by CVD were examined. New complexes of the form (Y(hfac)sb3(glyme)), (hfac = \\{CFsb3C(O)CHC(O)CFsb3\\}sp-,\\ glyme=CHsb3O(CHsb2CHsb2O)sb{n}CHsb3 for n = 1-4) were synthesized and characterized spectroscopically. X-ray structural determinations of three new complexes were obtained. CVD reaction conditions were determined which give YOF films and, with catalyst-enhanced CVD, reaction conditions which give selective formation of Ysb2Osb3, YOF, or YFsb3. The films were studied by XPS, SEM, and XRD. Decomposition mechanisms which lead to film formation, together with a possible route for fluorine atom transfer from the ligand to the metal resulting in fluorine incorporation, were studied by analysis of exhaust products using GC-MS. Novel precursors of the form lbrack Ce(hfac)sb3(glyme)rbrack,\\ (hfac=\\{CFsb3C(O)CHC(O)CFsb3\\}sp-,\\ glyme=CHsb3O(CHsb2CHsb2O)sb{n}CHsb3, n = 1-4) for CVD of ceria were

  6. Effect of Some Metal Ion Dopants on Electrochemical Properties of Ni(OH)2 Film Electrode

    Institute of Scientific and Technical Information of China (English)

    ZHANG Heng-bin; LIU Han-san; CAO Xue-jing; SUN Chia-chung

    2003-01-01

    The Ni(OH)2 film electrodes doped respectively with alkali-earth metal aluminum, lead, partial transition metal and some rare-earth metal(altogether 17 kinds of metals) ions were prepared by cathode electrodeposition. The electrode reaction reversibility, the difficult extent of oxygen evolution, the proton diffusion coefficient, the discharge potential of middle value and the active material utilization of the Ni(OH)2 film electrode were compared with those of the ones doped with the metal ions by means of cyclic voltammetry, potential step and constant current charge-discharge experiments. It was found that Ca2+, Co2+, Cd2+, Al3+ etc. have obviously positive effect.

  7. Decomposition of ethylene carbonate on electrodeposited metal thin film anode

    Energy Technology Data Exchange (ETDEWEB)

    Bridel, Jean-Sebastien; Grugeon, Sylvie; Laruelle, Stephane; Tarascon, Jean-Marie [Laboratoire de Reactivite et Chimie des Solides, Universite de Picardie Jules Verne CNRS (UMR-6007), Faculte des Sciences, 33 rue Saint-Leu 80039, Amiens Cedex (France); Hassoun, Jusef; Reale, Priscilla; Scrosati, Bruno [Chemistry Department, University of Rome ' ' La Sapienza' ' , 00185 Roma (Italy)

    2010-04-02

    Metals capable of forming alloys with Li are of great interest as an alternative to present carbon electrodes, hence the importance of knowing their interactions with electrolytes is necessary. Herein we report further on the high-voltage extra irreversibility of Sn electrodeposited thin films vs. Li in EC-DMC 1 M LiPF{sub 6} electrolytes. We show that this high-voltage irreversibility is strongly dependent upon the electrolyte composition as demonstrated by its disappearance in EC-free electrolytes. This finding coupled with IR spectroscopy measurements provides direct evidence for the tin-driven catalytic degradation of EC during the discharge of Sn/Li cells. From an electrochemical survey of various metals, capable of alloying with Li, we found that Bi and Pb behaved like Sn while Si and Sb did not act as catalysts towards EC degradation. A rationale for such behaviour is proposed, a procedure to bypass EC degradation with the addition of VC is presented, and an explanation for the non-observance of catalytic-driven EC degradation for Sn/C composites is provided. (author)

  8. Characteristic mechanical properties and complex ordered structures in metal films on liquid substrates

    Institute of Scientific and Technical Information of China (English)

    YU Senjiang; ZHANG Yongju; WU Liangneng; CUI Yujian; GE Hongliang

    2006-01-01

    Several metal (such as aluminum, iron etc.) film systems deposited on liquid (silicone oil) substrates have been successfully fabricated by a thermal evaporation method, and the special mechanical properties and complex ordered surface structures have been systematically studied. The experimental results show that there exists a compressive stress gradient in these films, making cracks nucleate at the film edges and then extend to the central regions gradually. Because the interaction between solid films and liquid substrates in the tangent direction is very small, the metal films can motion freely on the oil surfaces as a whole. In order to release the compressive stress, the broken film pieces collide, crush and superpose each other, which finally results in the formation of ordered band- shaped structures with an anti-symmetric characteristic. Based on the special mechanical properties of these nearly free sustained films, the morphologies and growth behaviors of the ordered structures are analyzed and discussed in detail.

  9. Wide-area thin film metal-semiconductor-metal photodetectors for lidar applications

    Science.gov (United States)

    Morrison, Charles B.; Glinz, Andreas P.; Zhu, Zheng; Bechtel, James H.; Frimel, Steven M.; Roenker, Kenneth P.

    1998-04-01

    Novel interdigitated metal-semiconductor-metal structures offer new approaches for the development of broad-area, high-speed photodetectors to be used in optical free space communications and light detection and ranging applications. Inherent advantages include: lower capacitance than typical p-i-n structures, a wide dynamic range, and ease of fabrication. We have constructed broad area metal- semiconductor-metal photodetectors (MSM-PDs) by means of epitaxial liftoff and grafting technologies. Two computer models have been used to examine the effects of design parameters on the performance of broad-area, high-speed MSM- PD devices. The first model indicates that inverting the membrane so that the electrodes are placed between the non- conducting host substrate and the semiconductor material improves the signal-to-noise ration of the device, expanding its dynamic range. This model suggests that processing of the backside of the semiconductor material with antireflection coatings further improves device performance. Carrier collection behavior described by the second model suggests new electrode configurations for improved high speed operation which can only be applied to an inverted MSM-PD carried on a thin film membrane. A number of different fully passivated large area MSM-PD configurations have been fabricated and tested. Initial dark current data are compared favorably to published results.

  10. Effect of metallic coatings on thermoelectric properties of lead telluride films

    Energy Technology Data Exchange (ETDEWEB)

    Ukhlinov, G.A.; Lakhno, I.G. (Moskovskij Inst. Ehlektronnoj Tekhniki (USSR))

    1984-05-01

    Effect of sprayed coatings of different metals on thermoelectric properties of lead telluride films was investigated. The basic films were prepared by the method of vacuum thermal evaporation of sample of stoichiometric lead telluride at 5x10/sup -4/ Pa residual pressure on mica (muscovite) sublayer at 330-350 deg C and approximately 10 nm/s deposition rate. It was established that fine coatings of copper, silver and gold modify sufficiently electric properties of lead telluride films. The effect is conditioned mainly by decoration and electric shunting of grain boundaries by metal island, which removes the contribution of grain boundaries to film electric conductivity.

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

  12. Diffusion and photoswitching in nanoporous thin films of metal-organic frameworks

    Science.gov (United States)

    Heinke, Lars

    2017-05-01

    Nanoporous metal-organic frameworks (MOFs) are intensively investigated with respect to various applications such as in gas storage, in molecular separation and as sensors. In all these applications, the interaction with the guest molecules in the nanopores, as well as the diffusion properties, are crucial. In this topical review, thin MOF films, referred to as surface-mounted MOFs (SURMOFs), are discussed as a well-defined model system for detailed mass transfer studies. The origins of mass transport hindering surface barriers, which often slow down the mass transfer tremendously, and the slow diffusion of large molecules, are investigated by using thin MOF films. Another focus of this topical review is on photoswitchable MOF films. Azobenzene side groups in the MOF structure allow a remote control of the adsorption and diffusion properties. This is employed for demonstrating the remote-controlled release from a nanoporous container as well as for membrane separation where the separation factor can be continuously tuned by light irradiation.

  13. Robust synthesis and continuous manufacturing of carbon nanotube forests and graphene films

    Science.gov (United States)

    Polsen, Erik S.

    Successful translation of the outstanding properties of carbon nanotubes (CNTs) and graphene to commercial applications requires highly consistent methods of synthesis, using scalable and cost-effective machines. This thesis presents robust process conditions and a series of process operations that will enable integrated roll-to-roll (R2R) CNT and graphene growth on flexible substrates. First, a comprehensive study was undertaken to establish the sources of variation in laboratory CVD growth of CNT forests. Statistical analysis identified factors that contribute to variation in forest height and density including ambient humidity, sample position in the reactor, and barometric pressure. Implementation of system modifications and user procedures reduced the variation in height and density by 50% and 54% respectively. With improved growth, two new methods for continuous deposition and patterning of catalyst nanoparticles for CNT forest growth were developed, enabling the diameter, density and pattern geometry to be tailored through the control of process parameters. Convective assembly of catalyst nanoparticles in solution enables growth of CNT forests with density 3-fold higher than using sputtered catalyst films with the same growth parameters. Additionally, laser printing of magnetic ink character recognition toner provides a large scale patterning method, with digital control of the pattern density and tunable CNT density via laser intensity. A concentric tube CVD reactor was conceptualized, designed and built for R2R growth of CNT forests and graphene on flexible substrates helically fed through the annular gap. The design enables downstream injection of the hydrocarbon source, and gas consumption is reduced 90% compared to a standard tube furnace. Multi-wall CNT forests are grown continuously on metallic and ceramic fiber substrates at 33 mm/min. High quality, uniform bi- and multi-layer graphene is grown on Cu and Ni foils at 25 - 495 mm/min. A second machine

  14. Quantum critical transport at a continuous metal-insulator transition

    OpenAIRE

    Haldar, P.; Laad, M. S.; Hassan, S. R.

    2016-01-01

    In contrast to the first-order correlation-driven Mott metal-insulator transition (MIT), contin- uous disorder-driven transitions are intrinsically quantum critical. Here, we investigate transport quantum criticality in the Falicov-Kimball model, a representative of the latter class in the "strong disorder" category. Employing cluster-dynamical mean-field theory (CDMFT), we find clear and anomalous quantum critical scaling behavior manifesting as perfect mirror symmetry of scaling curves on b...

  15. Texture in Metallic and Ceramic Films and Coatings

    OpenAIRE

    Czerwinski, F; J. A. Szpunar

    1999-01-01

    The properties of films and coatings can be optimized for a variety of applications by modifying their texture. Understanding how the texture in thin films is formed and how it can be controlled during film growth process is one of the most important areas of texture research. Several examples were selected to illustrate how the texture in films and coatings is developed and to explain how various properties of films are affected by texture. In particular, texture development during electrode...

  16. Oxidation kinetics of Ni metallic films: Formation of NiO-based resistive switching structures

    Energy Technology Data Exchange (ETDEWEB)

    Courtade, L.; Turquat, Ch. [L2MP, Laboratoire Materiaux et Microelectronique de Provence, UMR CNRS 6137, Universite du Sud Toulon Var, BP 20132, F-83957 La Garde Cedex (France); Muller, Ch. [L2MP, Laboratoire Materiaux et Microelectronique de Provence, UMR CNRS 6137, Universite du Sud Toulon Var, BP 20132, F-83957 La Garde Cedex (France)], E-mail: christophe.muller@l2mp.fr; Lisoni, J.G.; Goux, L.; Wouters, D.J. [IMEC, Interuniversity MicroElectronics Center, Kapeldreef 75, B-3001 Leuven (Belgium); Goguenheim, D. [L2MP, Laboratoire Materiaux et Microelectronique de Provence, UMR CNRS 6137, ISEN-Toulon, Maison des Technologies, Place Georges Pompidou, F-83000 Toulon (France); Roussel, P. [UCCS, Unite de Catalyse et Chimie du Solide, UMR CNRS 8181, ENSCL, BP 90108, F-59652 Villeneuve d' Ascq (France); Ortega, L. [Laboratoire de Cristallographie, UPR CNRS 5031, BP 166, F-38042 Grenoble Cedex 9 (France)

    2008-04-30

    Resistive switching controlled by external voltage has been reported in many Metal/Resistive oxide/Metal (MRM) structures in which the resistive oxide was simple transition metal oxide thin films such as NiO or TiO{sub 2} deposited by reactive sputtering. In this paper, we have explored the possibility to form NiO-based MRM structures from the partial oxidation of a blanket Ni metallic film using a Rapid Thermal Annealing route, the remaining Ni layer being used as bottom electrode. X-ray diffraction was used to apprehend the Ni oxidation kinetics while transmission electron microscopy enabled investigating local microstructure and film interfaces. These analyses have especially emphasized the predominant role of the as-deposited Ni metallic film microstructure (size and orientation of crystallites) on (i) oxidation kinetics, (ii) NiO film microstructural characteristics (crystallite size, texture and interface roughness) and (iii) subsequent electrical behavior. On this latter point, the as-grown NiO films were initially in the low resistance ON state without the electro-forming step usually required for sputtered films. Above the threshold voltage varying from 2 to 5 V depending on oxidation conditions, the Pt/NiO/Ni MRM structures irreversibly switched into the high resistance OFF state. This irreversibility is thought to originate in the microstructure of the NiO films that would cause the difficulty to re-form conductive paths.

  17. Preparation of bioactive titania films on titanium metal via anodic oxidation.

    Science.gov (United States)

    Cui, X; Kim, H-M; Kawashita, M; Wang, L; Xiong, T; Kokubo, T; Nakamura, T

    2009-01-01

    To research the crystal structure and surface morphology of anodic films on titanium metal in different electrolytes under various electrochemical conditions and investigate the effect of the crystal structure of the oxide films on apatite-forming ability in simulated body fluid (SBF). Titanium oxide films were prepared using an anodic oxidation method on the surface of titanium metal in four different electrolytes: sulfuric acid, acetic acid, phosphoric acid and sodium sulfate solutions with different voltages for 1 min at room temperature. Anodic films that consisted of rutile and/or anatase phases with porous structures were formed on titanium metal after anodizing in H(2)SO(4) and Na(2)SO(4) electrolytes, while amorphous titania films were produced after anodizing in CH(3)COOH and H(3)PO(4) electrolytes. Titanium metal with the anatase and/or rutile crystal structure films showed excellent apatite-forming ability and produced a compact apatite layer covering all the surface of titanium after soaking in SBF for 7d, but titanium metal with amorphous titania layers was not able to induce apatite formation. The resultant apatite layer formed on titanium metal in SBF could enhance the bonding strength between living tissue and the implant. Anodic oxidation is believed to be an effective method for preparing bioactive titanium metal as an artificial bone substitute even under load-bearing conditions.

  18. The influence of nanoscale morphology on the resistivity of cluster-assembled nanostructured metallic thin films

    Energy Technology Data Exchange (ETDEWEB)

    Barborini, E; Bertolini, G; Repetto, P; Leccardi, M; Vinati, S [Tethis srl, via Franco Russoli 3, 20143 Milano (Italy); Corbelli, G; Milani, P, E-mail: emanuele.barborini@tethis-lab.co, E-mail: pmilani@mi.infn.i [CIMAINA and Dipartimento di Fisica, Universita di Milano, via Celoria 16, 20133 Milano (Italy)

    2010-07-15

    We have studied in situ the evolution of the electrical resistivity of Fe, Pd, Nb, W and Mo cluster-assembled films during their growth by supersonic cluster beam deposition. We observed resistivity of cluster-assembled films several orders of magnitude larger than the bulk, as well as an increase in resistivity by increasing the film thickness in contrast to what was observed for atom-assembled metallic films. This suggests that the nanoscale morphological features typical of ballistic films growth, such as the minimal cluster-cluster interconnection and the evolution of surface roughness with thickness, are responsible for the observed behaviour.

  19. Ferroelectric-Like Properties of Amorphous Metal Oxide Thin Films Prepared by Sol-Gel Technique.

    Science.gov (United States)

    Xu, Yuhuan

    1995-01-01

    Advances in the field of both optical and electrical integrated circuit devices require new thin film materials. Ferroelectric materials have attractive properties such as hysteresis behavior, pyroelectricity, piezoelectricity and nonlinear optical properties. Many ferroelectric thin films have been successfully prepared from metal organic compounds via sol-gel processing. Thus far, research has concentrated upon polycrystalline or epitaxial ferroelectric films. For amorphous ferroelectric thin films, preliminary experimental results in our laboratory indicated that these amorphous films possessed good ferroelectric -like properties. The purpose of this research is (1) to fabricate amorphous metal oxide thin films by the sol-gel technique, (2) to determine whether these amorphous metal oxide thin films have ferroelectric-like properties and (3) to propose a theoretical model ("ferrons model") to explain the ferroelectric-like properties of amorphous thin films, which deals with a structure of permanent dipoles of "partially ordered clusters" (ferrons) in the amorphous films. The theoretical model is based on our experimental results of thin films of two amorphous materials (barium titanite and lead zirconate titanate). This research may provide a new functional material which could be useful for producing integrated electronic and electrooptic devices.

  20. Luminescent, freestanding composite films of Au15 for specific metal ion sensing.

    Science.gov (United States)

    George, Anu; Shibu, E S; Maliyekkal, Shihabudheen M; Bootharaju, M S; Pradeep, T

    2012-02-01

    A highly luminescent freestanding film composed of the quantum cluster, Au(15), was prepared. We studied the utility of the material for specific metal ion detection. The sensitivity of the red emission of the cluster in the composite to Cu(2+) has been used to make a freestanding metal ion sensor, similar to pH paper. The luminescence of the film was stable when exposed to several other metal ions such as Hg(2+), As(3+), and As(5+). The composite film exhibited visual sensitivity to Cu(2+) up to 1 ppm, which is below the permissible limit (1.3 ppm) in drinking water set by the U.S. environmental protection agency (EPA). The specificity of the film for Cu(2+) sensing may be due to the reduction of Cu(2+) to Cu(1+)/Cu(0) by the glutathione ligand or the Au(15) core. Extended stability of the luminescence of the film makes it useful for practical applications.

  1. Thin Films from Solvated Metal Atoms and Metal-Metal Bonded Compounds

    Science.gov (United States)

    1988-07-01

    Departamento de Quimica , Universidad de Con- palladium colloids. cepcion, Casilla 3-C, Concepcion, Chile. (2) Department of Physics. (3) Turkevich, J.; Stevenson... change would be the period before particle stabilization that is important. realized. Indeed, with this procedure the resulting Pd And if metal...case controlled by concentration effects. 21 With palladium we electrophoretic behavior changed markedly, and mea- , invariably obtained particle sizes

  2. Two New Type Surface Polaritons Excited into Nanoholes in Metal Films

    Directory of Open Access Journals (Sweden)

    Minasyan V. N.

    2010-04-01

    Full Text Available We argue that the smooth metal-air interface should be regarded as a distinct dielectric medium, the skin of the metal. Here we present quantized Maxwell’s equations for electromagnetic field in an isotropic homogeneous medium, allowing us to solve the absorption anomaly property of these metal films. The results imply the existence of light quasi-particles with spin one and effective mass m = 2.5 E-5 me which in turn provide the presence of two type surface polaritons into nanoholes in metal films.

  3. Non-centrosymmetric behavior of a clay film ion-exchanged with chiral metal complexes.

    Science.gov (United States)

    Suzuki, Yasutaka; Matsunaga, Ryoya; Sato, Hisako; Kogure, Toshihiro; Yamagishi, Akihiko; Kawamata, Jun

    2009-12-07

    SHG measurements on a highly transparent clay film ion-exchanged with chiral metal complexes revealed that the mono-molecular layer of the chiral complexes in an interlayer space acquired a non-centrosymmetric character.

  4. Adherence of ion beam sputter deposited metal films on H-13 steel

    Science.gov (United States)

    Mirtich, M. J.

    1980-01-01

    An electron bombardment argon ion source sputter deposited 17 metals and metal oxides on H-13 steel. The films ranged 1 to 8 micrometers in thickness and their adherence was generally greater than the capacity of the measuring device; adherence quality depended on proper precleaning of the substrate before deposition. N2 or air was introduced for correct stoichiometry in metallic compounds. Au, Ag, MgO, and Ta5Si3 films 8 microns thick have bond strength equal to 1 micron coatings; the bond strength of pure metallic films up to 5 microns thick was greater than the epoxy to film bond (8000 psi). The results of exposures of coated material to temperatures up to 700 C are presented.

  5. Polymer Nanocomposite Film with Metal Rich Surface Prepared by In Situ Single-Step Formation of Palladium Nanoparticles: An Interesting Way to Combine Specific Functional Properties

    Directory of Open Access Journals (Sweden)

    David Thompson

    2016-10-01

    Full Text Available This paper presents a continuous single-step route that permits preparation of a thermostable polymer/metal nanocomposite film and to combine different functional properties in a unique material. More precisely, palladium nanoparticles are in situ generated in a polyimide matrix thanks to a designed curing cycle which is applied to a polyamic acid/metal precursor solution cast on a glass plate. A metal-rich surface layer which is strongly bonded to the bulk film is formed in addition to homogeneously dispersed metal nanoparticles. This specific morphology leads to obtaining an optically reflective film. The metal nanoparticles act as gas diffusion barriers for helium, oxygen, and carbon dioxide; they induce a tortuosity effect which allows dividing the gas permeation coefficients by a factor near to 2 with respect to the neat polyimide matrix. Moreover, the ability of the in situ synthesized palladium nanoparticles to entrap hydrogen is evidenced. The nanocomposite film properties can be modulated as a function of the location of the film metal-rich surface with respect to the hydrogen feed. The synthesized nanocomposite could represent a major interest for a wide variety of applications, from specific coatings for aerospace or automotive industry, to catalysis applications or sensors.

  6. Soft matter beats hard matter: rupturing of thin metallic films induced by mass transport in photosensitive polymer films.

    Science.gov (United States)

    Yadavalli, Nataraja Sekhar; Linde, Felix; Kopyshev, Alexey; Santer, Svetlana

    2013-08-28

    The interface between thin films of metal and polymer materials play a significant role in modern flexible microelectronics viz., metal contacts on polymer substrates, printed electronics and prosthetic devices. The major emphasis in metal-polymer interface is on studying how the externally applied stress in the polymer substrate leads to the deformation and cracks in metal film and vice versa. Usually, the deformation process involves strains varying over large lateral dimensions because of excessive stress at local imperfections. Here we show that the seemingly random phenomena at macroscopic scales can be rendered rather controllable at submicrometer length scales. Recently, we have created a metal-polymer interface system with strains varying over periods of several hundred nanometers. This was achieved by exploiting the formation of surface relief grating (SRG) within the azobenzene containing photosensitive polymer film upon irradiation with light interference pattern. Up to a thickness of 60 nm, the adsorbed metal film adapts neatly to the forming relief, until it ultimately ruptures into an array of stripes by formation of highly regular and uniform cracks along the maxima and minima of the polymer topography. This surprising phenomenon has far-reaching implications. This is the first time a direct probe is available to estimate the forces emerging in SRG formation in glassy polymers. Furthermore, crack formation in thin metal films can be studied literally in slow motion, which could lead to substantial improvements in the design process of flexible electronics. Finally, cracks are produced uniformly and at high density, contrary to common sense. This could offer new strategies for precise nanofabrication procedures mechanical in character.

  7. Analysis of Second-Harmonic Generation from CuttbPc LB Film/Metal Interface

    Institute of Scientific and Technical Information of China (English)

    程晓曼; 姚素薇; 李成全; 间中孝彰; 岩本光正

    2004-01-01

    Second-harmonic generation signals from a CuttbPc LB film deposited on metal (Al or Au)-glass substrates were investigated. It was observed that there were two second-harmonic peaks at the wavelength of 1060 and 1250nm in the CuttbPc/A1 film, but only one peak at 1050nm in the CuttbPc/Au film. Meanwhile the surface electric potentials (SEP) at the interfaces of LB film/metals were also measured using a Kelvin probe. The SEP in the CuttbPc/Al decreases and eventually approaches a saturated value of -1.0 V as the film thickness increases,while the SEP in the CuttbPc/Au is nearly zero. Based on the experimental results and theoretical analysis, it was considered that the space-charge-induced electric field makes a main contribution to the second-harmonic generation at 1250nm in the CuttbPc/Al film.

  8. Preventing bacterial growth on implanted device with an interfacial metallic film and penetrating X-rays.

    Science.gov (United States)

    An, Jincui; Sun, An; Qiao, Yong; Zhang, Peipei; Su, Ming

    2015-02-01

    Device-related infections have been a big problem for a long time. This paper describes a new method to inhibit bacterial growth on implanted device with tissue-penetrating X-ray radiation, where a thin metallic film deposited on the device is used as a radio-sensitizing film for bacterial inhibition. At a given dose of X-ray, the bacterial viability decreases as the thickness of metal film (bismuth) increases. The bacterial viability decreases with X-ray dose increases. At X-ray dose of 2.5 Gy, 98% of bacteria on 10 nm thick bismuth film are killed; while it is only 25% of bacteria are killed on the bare petri dish. The same dose of X-ray kills 8% fibroblast cells that are within a short distance from bismuth film (4 mm). These results suggest that penetrating X-rays can kill bacteria on bismuth thin film deposited on surface of implant device efficiently.

  9. Nanoscale Structure, Dynamics, and Aging Behavior of Metallic Glass Thin Films.

    Science.gov (United States)

    Burgess, J A J; Holt, C M B; Luber, E J; Fortin, D C; Popowich, G; Zahiri, B; Concepcion, P; Mitlin, D; Freeman, M R

    2016-08-08

    Scanning tunnelling microscopy observations resolve the structure and dynamics of metallic glass Cu100-xHfx films and demonstrate scanning tunnelling microscopy control of aging at a metallic glass surface. Surface clusters exhibit heterogeneous hopping dynamics. Low Hf concentration films feature an aged surface of larger, slower clusters. Argon ion-sputtering destroys the aged configuration, yielding a surface in constant fluctuation. Scanning tunnelling microscopy can locally restore the relaxed state, allowing for nanoscale lithographic definition of aged sections.

  10. Nanoscale Structure, Dynamics, and Aging Behavior of Metallic Glass Thin Films

    Science.gov (United States)

    Burgess, J. A. J.; Holt, C. M. B.; Luber, E. J.; Fortin, D. C.; Popowich, G.; Zahiri, B.; Concepcion, P.; Mitlin, D.; Freeman, M. R.

    2016-01-01

    Scanning tunnelling microscopy observations resolve the structure and dynamics of metallic glass Cu100−xHfx films and demonstrate scanning tunnelling microscopy control of aging at a metallic glass surface. Surface clusters exhibit heterogeneous hopping dynamics. Low Hf concentration films feature an aged surface of larger, slower clusters. Argon ion-sputtering destroys the aged configuration, yielding a surface in constant fluctuation. Scanning tunnelling microscopy can locally restore the relaxed state, allowing for nanoscale lithographic definition of aged sections. PMID:27498698

  11. Percolation metal-insullator transition in BiSrCaCuO films

    Science.gov (United States)

    Okunev, V. D.; Pafomov, N. N.; Svistunov, V. M.; Lewandowski, S. J.; Gierlowski, P.; Kula, W.

    1996-02-01

    An experimental investigation of the metal-insulator trnasition in BiSrCaCuO (BSCCO) films is reported. We performed resistivity, optical-absorption and critical-temperature measurements on several samples obtained by different technological methods. The results agree well with the percolation mechanism of the metal-insulator transition and show interesting correlations between room-temperature conductivity and superconducting properties of the investigated films.

  12. Development of thin film oxygen transport membranes on metallic supports

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Ye

    2012-04-25

    Asymmetric membrane structure has an attractive potential in the application of O{sub 2}/N{sub 2} gas separation membrane for the future membrane-based fossil fuel power plant using oxyfuel technology, which will reduce the carbon dioxide emission. The aim of this study is the development of a metal supported multi-layer membrane structure with a thin film top membrane layer and porous ceramic interlayers. Four perovskite materials were studied as candidate membrane materials. Material properties of these perovskite materials were investigated and compared. La{sub 0.58}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCF58428) showed sufficient oxygen permeability, an acceptable thermal expansion coefficient and a moderate sintering temperature. Alternatively, Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (BSCF5582) is considered obtaining very high oxygen permeability but a higher thermal expansion and a lower thermal stability than LSCF58428. Four different Ni-based alloys were studied as candidate substrate materials in the asymmetric membrane structure. The chromia-scale alloys (Hastelloy X, Inconel 600 and Haynes 214) caused Cr poisoning of the membrane layer material LSCF58428 during high-temperature co-firing in air. NiCoCrAlY with a high Al content (12.7 wt%) was found to be the most promising substrate material. It showed a good chemical compatibility with perovskite materials at high temperatures. In order to bridge the highly porous substrate and the thin top membrane layer interlayers were developed. Two interlayers were coated by screen printing on the porous NiCoCrAlY substrate which was sintered at 1225 C in flowing H{sub 2} atmosphere. Screen printing pastes were optimized by investigating various solvent and binder combinations and various ceramic powder contents. The first interlayer significantly improved the surface quality and the surface pore size has been reduced from 30-50{mu}m on the substrate to few {mu}m on the first

  13. Flexible Electronics Powered by Mixed Metal Oxide Thin Film Transistors

    Science.gov (United States)

    Marrs, Michael

    A low temperature amorphous oxide thin film transistor (TFT) and amorphous silicon PIN diode backplane technology for large area flexible digital x-ray detectors has been developed to create 7.9-in. diagonal backplanes. The critical steps in the evolution of the backplane process include the qualification and optimization of the low temperature (200 °C) metal oxide TFT and a-Si PIN photodiode process, the stability of the devices under forward and reverse bias stress, the transfer of the process to flexible plastic substrates, and the fabrication and assembly of the flexible detectors. Mixed oxide semiconductor TFTs on flexible plastic substrates suffer from performance and stability issues related to the maximum processing temperature limitation of the polymer. A novel device architecture based upon a dual active layer improves both the performance and stability. Devices are directly fabricated below 200 ºC on a polyethylene naphthalate (PEN) substrate using mixed metal oxides of either zinc indium oxide (ZIO) or indium gallium zinc oxide (IGZO) as the active semiconductor. The dual active layer architecture allows for adjustment to the saturation mobility and threshold voltage stability without the requirement of high temperature annealing, which is not compatible with flexible plastic substrates like PEN. The device performance and stability is strongly dependent upon the composition of the mixed metal oxide; this dependency provides a simple route to improving the threshold voltage stability and drive performance. By switching from a single to a dual active layer, the saturation mobility increases from 1.2 cm2/V-s to 18.0 cm2/V-s, while the rate of the threshold voltage shift decreases by an order of magnitude. This approach could assist in enabling the production of devices on flexible substrates using amorphous oxide semiconductors. Low temperature (200°C) processed amorphous silicon photodiodes were developed successfully by balancing the tradeoffs

  14. Thin films of copper oxide and copper grown by atomic layer deposition for applications in metallization systems of microelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Waechtler, Thomas

    2010-05-25

    Copper-based multi-level metallization systems in today's ultralarge-scale integrated electronic circuits require the fabrication of diffusion barriers and conductive seed layers for the electrochemical metal deposition. Such films of only several nanometers in thickness have to be deposited void-free and conformal in patterned dielectrics. The envisaged further reduction of the geometric dimensions of the interconnect system calls for coating techniques that circumvent the drawbacks of the well-established physical vapor deposition. The atomic layer deposition method (ALD) allows depositing films on the nanometer scale conformally both on three-dimensional objects as well as on large-area substrates. The present work therefore is concerned with the development of an ALD process to grow copper oxide films based on the metal-organic precursor bis(trin- butylphosphane)copper(I)acetylacetonate [({sup n}Bu{sub 3}P){sub 2}Cu(acac)]. This liquid, non-fluorinated {beta}-diketonate is brought to react with a mixture of water vapor and oxygen at temperatures from 100 to 160 C. Typical ALD-like growth behavior arises between 100 and 130 C, depending on the respective substrate used. On tantalum nitride and silicon dioxide substrates, smooth films and selfsaturating film growth, typical for ALD, are obtained. On ruthenium substrates, positive deposition results are obtained as well. However, a considerable intermixing of the ALD copper oxide with the underlying films takes place. Tantalum substrates lead to a fast self-decomposition of the copper precursor. As a consequence, isolated nuclei or larger particles are always obtained together with continuous films. The copper oxide films grown by ALD can be reduced to copper by vapor-phase processes. If formic acid is used as the reducing agent, these processes can already be carried out at similar temperatures as the ALD, so that agglomeration of the films is largely avoided. Also for an integration with subsequent

  15. Properties of alumina films by atmospheric pressure metal-organic chemical vapour deposition

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Corbach, van H.D.; Fransen, T.; Gellings, P.J.

    1994-01-01

    Thin alumina films were deposited at low temperatures (290–420°C) on stainless steel, type AISI 304. The deposition process was carried out in nitrogen by metal-organic chemical vapour deposition using aluminum tri-sec-butoxide. The film properties including the protection of the underlying substrat

  16. The mechanical properties of thin alumina film deposited by metal-organic chemical vapour deposition

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Gellings, P.J.; Vendel, van de D.; Metselaar, H.S.C.; Corbach, van H.D.; Fransen, T.

    1995-01-01

    Amorphous alumina films were deposited by metal-organic chemical vapour deposition (MOCVD) on stainless steel, type AISI 304. The MOCVD experiments were performed in nitrogen at low and atmospheric pressures. The effects of deposition temperature, growth rate and film thickness on the mechanical pro

  17. Surface treatment of polyimide film for metal magnetron deposition in vacuum

    Science.gov (United States)

    Petrov, V.; Vertyanov, D.; Timoshenkov, S.; Nikolaev, V.

    2014-12-01

    This paper brings forward a solution for acquisition of good quality metallization layers on the polyimide substrate by magnetron deposition in vacuum environment. Different film type structures have been analyzed after refining and activation surface treatment operations. Positive effect was shown after the application of polyimide lacquer for surface dielectric film planarization and for structural defects elimination.

  18. Luminescent metal-organic framework films as highly sensitive and fast-response oxygen sensors.

    Science.gov (United States)

    Dou, Zhongshang; Yu, Jiancan; Cui, Yuanjing; Yang, Yu; Wang, Zhiyu; Yang, Deren; Qian, Guodong

    2014-04-16

    Luminescent metal-organic framework films, CPM-5⊃Tb(3+) and MIL-100(In)⊃Tb(3+), have been constructed by postfunctionalization of two porous indium-organic frameworks with different structures, respectively. The MIL-100(In)⊃Tb(3+) film shows high oxygen sensitivity (KSV = 7.59) and short response/recovery time (6 s/53 s).

  19. Tailor-made oxide architectures attained by molecularly permeable metal-oxide organic hybrid thin films.

    Science.gov (United States)

    Sarkar, Debabrata; Taffa, Dereje Hailu; Ishchuk, Sergey; Hazut, Ori; Cohen, Hagai; Toker, Gil; Asscher, Micha; Yerushalmi, Roie

    2014-08-21

    Tailor-made metal oxide (MO) thin films with controlled compositions, electronic structures, and architectures are obtained via molecular layer deposition (MLD) and solution treatment. Step-wise formation of permeable hybrid films by MLD followed by chemical modification in solution benefits from the versatility of gas phase reactivity on surfaces while maintaining flexibility which is more common at the liquid phase.

  20. Structure of the Buried Metal-Molecule Interface in Organic Thin Film Devices

    DEFF Research Database (Denmark)

    Hansen, Christian Rein; Sørensen, Thomas Just; Glyvradal, Magni

    2009-01-01

    By use of specular X-ray reflectivity (XR) the structure of a metal-covered organic thin film device is measured with angstrom resolution. The model system is a Langmuir-Blodgett (LB) film, sandwiched between a silicon substrate and a top electrode consisting of 25 Å titanium and 100 Å aluminum...

  1. The spatial thickness distribution of metal films produced by large area pulsed laser deposition

    DEFF Research Database (Denmark)

    Pryds, Nini; Schou, Jørgen; Linderoth, Søren

    2007-01-01

    Thin films of metals have been deposited in the large-area Pulsed Laser Deposition (PLD) Facility at Riso National Laboratory. Thin films of Ag and Ni were deposited with laser pulses from an excimer laser at 248 nm with a rectangular beam spot at a fluence of 10 J/cm(2) on glass substrates of 12...

  2. High Seebeck effects from conducting polymer: Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) based thin-film device with hybrid metal/polymer/metal architecture

    Energy Technology Data Exchange (ETDEWEB)

    Stanford, Michael G [ORNL; Wang, Hsin [ORNL; Ivanov, Ilia N [ORNL; Hu, Bin [University of Tennessee, Knoxville (UTK)

    2012-01-01

    Conductive polymers are of particular interest for thermoelectric applications due to their low thermal conductivity and relatively high electrical conductivity. In this study, commercially available conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) was used in a hybrid metal/polymer/metal thin film design in order to achieve a high Seebeck coefficient with the value of 252lV/k on a relatively low temperature scale. Polymer film thickness was varied in order to investigate its influence on the Seebeck effect. The high Seebeck coefficient indicates that the metal/polymer/metal design can develop a large entropy difference in internal energy of charge carriers between high and low-temperature metal electrodes to develop electrical potential due to charge transport in conducting polymer film through metal/polymer interface. Therefore, the metal/polymer/metal structure presents a new design to combine inorganic metals and organic polymers in thin-film form to develop Seebeck devices

  3. Reorientation of magnetic anisotropy in obliquely sputtered metallic thin films

    NARCIS (Netherlands)

    Lisfi, A.; Lodder, J.C.; Wormeester, H.; Poelsema, B.

    2002-01-01

    Reorientation in the magnetic anisotropy as a function of film thickness has been observed in Co-Ni and Co thin films, obliquely sputtered on a polyethylene terephthalate substrate at a large incidence angle (70°). This effect is a consequence of the low magnetocrystalline anisotropy of the films (f

  4. Mechanical manipulation of magnetic domains in continuous and patterned magnetostrictive FeGa thin films

    Science.gov (United States)

    Alexander, Paris; Fackler, Sean; Takeuchi, Ichiro; Cumings, John

    2013-03-01

    The controlled and reversible switching of magnetic domains using static electric fields has been previously demonstrated via magneto-electric (ME) coupling in a multiferroic system [T. Brintlinger, Nano Lett. 10, 1219(2010)]. In these systems, enhanced magnetostriction allows for magnetic switching in response to an electrically induced deformation. Here we demonstrate the nature of magnetic switching using mechanical stress alone. Magnetostrictive iron-gallium (Fe70Ga30) thin films are deposited on flexible free-standing membranes, and patterned to square arrays. Using a mechanically manipulated tip a strain is directly applied to the film. We observe the resulting magnetization dynamics using Lorentz-force transmission electron microscopy (LTEM). The varied hysteretic behaviors under applied magnetic and strain fields will be presented for both continuous and patterned films. This work was supported by the NSF-MRSEC at the University of Maryland, DMR 0520471.

  5. Shape-controlled continuous synthesis of metal nanostructures

    Science.gov (United States)

    Sebastian, Victor; Smith, Christopher D.; Jensen, Klavs F.

    2016-03-01

    A segmented flow-based microreactor is used for the continuous production of faceted nanocrystals. Flow segmentation is proposed as a versatile tool to manipulate the reduction kinetics and control the growth of faceted nanostructures; tuning the size and shape. Switching the gas from oxygen to carbon monoxide permits the adjustment in nanostructure growth from 1D (nanorods) to 2D (nanosheets). CO is a key factor in the formation of Pd nanosheets and Pt nanocubes; operating as a second phase, a reductant, and a capping agent. This combination confines the growth to specific structures. In addition, the segmented flow microfluidic reactor inherently has the ability to operate in a reproducible manner at elevated temperatures and pressures whilst confining potentially toxic reactants, such as CO, in nanoliter slugs. This continuous system successfully synthesised Pd nanorods with an aspect ratio of 6; thin palladium nanosheets with a thickness of 1.5 nm; and Pt nanocubes with a 5.6 nm edge length, all in a synthesis time as low as 150 s.A segmented flow-based microreactor is used for the continuous production of faceted nanocrystals. Flow segmentation is proposed as a versatile tool to manipulate the reduction kinetics and control the growth of faceted nanostructures; tuning the size and shape. Switching the gas from oxygen to carbon monoxide permits the adjustment in nanostructure growth from 1D (nanorods) to 2D (nanosheets). CO is a key factor in the formation of Pd nanosheets and Pt nanocubes; operating as a second phase, a reductant, and a capping agent. This combination confines the growth to specific structures. In addition, the segmented flow microfluidic reactor inherently has the ability to operate in a reproducible manner at elevated temperatures and pressures whilst confining potentially toxic reactants, such as CO, in nanoliter slugs. This continuous system successfully synthesised Pd nanorods with an aspect ratio of 6; thin palladium nanosheets with a

  6. Characterization of quaternary metal oxide films by synchrotron x-ray fluorescence microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Perry, D.L.; Thompson, A.C.; Russo, R.E. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    A high demand for thin films in industrial technology has been responsible for the creation of new techniques for the fabrication of such films. One highly effective method for the syntheses of variable composition thin films is pulsed-laser deposition (PLD). The technique has a large number of characteristics which make it an attractive approach for making films. It offers rapid deposition rates, congruent material transfer, simple target requirements from which to make the films, in situ multilayer deposition, and no gas composition or pressure requirements. Additionally, the technique can also afford crystalline films and films with novel structures. Pulsed-laser deposition can be used to make films of semiconductors, insulators, high-temperature superconductors, diamond-like films, and piezoelectric materials. Quaternary metal oxides involving calcium, nickel, and potassium have been shown to be quite effective in the catalysis of coal gasification and methane coupling. One approach to incorporating all three of the metal oxides into one phase is the use of laser ablation to prepare films of the catalysts so that they may be used for coatings, smooth surfaces on which to conduct detailed studies of gas-solid interface reactions that are involved in catalytic processes, and other applications. The problem of dissimilar boiling points of the three metal oxides system is overcome, since the laser ablation process effects the volatilization of all three components from the laser target essentially simultaneously. There is strong interest in gaining an understanding of the chemical and morphological aspects of the films that are deposited. Phenomena such as lattice defects and chemical heterogeneity are of interest. The experimental data discussed here are restricted to the matrix homogeneity of the films themselves for films which were void of microparticles.

  7. Optical and magneto-optical properties of metal phthalocyanine and metal porphyrin thin films.

    Science.gov (United States)

    Birnbaum, Tobias; Hahn, Torsten; Martin, Claudia; Kortus, Jens; Fronk, Michael; Lungwitz, Frank; Zahn, Dietrich R T; Salvan, Georgeta

    2014-03-12

    The optical constants together with the magneto-optical Voigt constants of several phthalocyanine (Pc) and methoxy functionalized tetraphenylporphyrin (TMPP) thin films prepared on silicon substrates are presented. The materials investigated are MePc with Me = Fe, Co, Ni, Cu, Zn and MeTMPP with Me = Cu, Ni. We also compared our results to the metal-free H2Pc, H2TPP and H2TMPP. The experimental results will be supported by electronic structure calculations based on density functional theory (DFT) and interpreted using the perimeter model initially proposed by Platt. The model allows for qualitative understanding of the forbidden character of transitions in planar, aromatic molecules, and is able to qualify differences between Pc and TMPP type materials.

  8. Continuous, Highly Flexible, and Transparent Graphene Films by Chemical Vapor Deposition for Organic Photovoltaics

    KAUST Repository

    Gomez De Arco, Lewis

    2010-05-25

    We report the implementation of continuous, highly flexible, and transparent graphene films obtained by chemical vapor deposition (CVD) as transparent conductive electrodes (TCE) in organic photovoltaic cells. Graphene films were synthesized by CVD, transferred to transparent substrates, and evaluated in organic solar cell heterojunctions (TCE/poly-3,4- ethylenedioxythiophene:poly styrenesulfonate (PEDOT:PSS)/copper phthalocyanine/fullerene/bathocuproine/aluminum). Key to our success is the continuous nature of the CVD graphene films, which led to minimal surface roughness (∼ 0.9 nm) and offered sheet resistance down to 230 Ω/sq (at 72% transparency), much lower than stacked graphene flakes at similar transparency. In addition, solar cells with CVD graphene and indium tin oxide (ITO) electrodes were fabricated side-by-side on flexible polyethylene terephthalate (PET) substrates and were confirmed to offer comparable performance, with power conversion efficiencies (η) of 1.18 and 1.27%, respectively. Furthermore, CVD graphene solar cells demonstrated outstanding capability to operate under bending conditions up to 138°, whereas the ITO-based devices displayed cracks and irreversible failure under bending of 60°. Our work indicates the great potential of CVD graphene films for flexible photovoltaic applications. © 2010 American Chemical Society.

  9. Effect of Continuous Multi-Walled Carbon Nanotubes on Thermal and Mechanical Properties of Flexible Composite Film.

    Science.gov (United States)

    Cha, Ji Eun; Kim, Seong Yun; Lee, Seung Hee

    2016-10-12

    To investigate the effect of continuous multi-walled carbon nanotubes (MWCNTs) on the thermal and mechanical properties of composites, we propose a fabrication method for a buckypaper-filled flexible composite film prepared by a two-step process involving buckypaper fabrication using vacuum filtration of MWCNTs, and composite film fabrication using the dipping method. The thermal conductivity and tensile strength of the composite film filled with the buckypaper exhibited improved results, respectively 76% and 275% greater than those of the individual MWCNT-filled composite film. It was confirmed that forming continuous MWCNT fillers is an important factor which determines the physical characteristics of the composite film. In light of the study findings, composite films using buckypaper as a filler and polydimethylsiloxane (PDMS) as a flexible matrix have sufficient potential to be applied as a heat-dissipating material, and as a flexible film with high thermal conductivity and excellent mechanical properties.

  10. Effect of Continuous Multi-Walled Carbon Nanotubes on Thermal and Mechanical Properties of Flexible Composite Film

    Directory of Open Access Journals (Sweden)

    Ji Eun Cha

    2016-10-01

    Full Text Available To investigate the effect of continuous multi-walled carbon nanotubes (MWCNTs on the thermal and mechanical properties of composites, we propose a fabrication method for a buckypaper-filled flexible composite film prepared by a two-step process involving buckypaper fabrication using vacuum filtration of MWCNTs, and composite film fabrication using the dipping method. The thermal conductivity and tensile strength of the composite film filled with the buckypaper exhibited improved results, respectively 76% and 275% greater than those of the individual MWCNT-filled composite film. It was confirmed that forming continuous MWCNT fillers is an important factor which determines the physical characteristics of the composite film. In light of the study findings, composite films using buckypaper as a filler and polydimethylsiloxane (PDMS as a flexible matrix have sufficient potential to be applied as a heat-dissipating material, and as a flexible film with high thermal conductivity and excellent mechanical properties.

  11. Determination of magnetic properties of multilayer metallic thin films

    CERN Document Server

    Birlikseven, C

    2000-01-01

    and magnetization measurements were taken. In recent year, Giant Magnetoresistance Effect has been attracting an increasingly high interest. High sensitivity magnetic field detectors and high sensitivity read heads of magnetic media can be named as important applications of these films. In this work, magnetic and electrical properties of single layer and thin films were investigated. Multilayer thin films were supplied by Prof. Dr. A. Riza Koeymen from Texas University. Multilayer magnetic thin films are used especially for magnetic reading and magnetic writing. storing of large amount of information into small areas become possible with this technology. Single layer films were prepared using the electron beam evaporation technique. For the exact determination of film thicknesses, a careful calibration of the thicknesses was made. Magnetic properties of the multilayer films were studied using the magnetization, magnetoresistance measurements and ferromagnetic resonance technique. Besides, by fitting the exper...

  12. Laser-induced desorption of overlayer films off a heated metal substrate

    Science.gov (United States)

    Gu, Xiang; Urbassek, Herbert M.

    2007-02-01

    The temperature-induced desorption of adsorbed overlayer films with thicknesses between 4 and 200 ML off a suddenly heated metal substrate is studied using molecular-dynamics simulation. We observe that the rapid heating vaporizes the surface-near part of the overlayer film. The initial heating-induced thermoelastic pressure and the vapor pressure in the vapor film drive the remaining film as a large relatively cold cluster away from the surface. In our simulations, the material present in the developing vapor film amounts to roughly 2 ML and is quite independent of the overlayer film thickness. For cluster thicknesses beyond 40 ML, the desorption time increases only little with film thickness, while the resulting cluster velocity decreases only slightly.

  13. Environmentally stable flexible metal-insulator-metal capacitors using zirconium-silicate and hafnium-silicate thin film composite materials as gate dielectrics.

    Science.gov (United States)

    Meena, Jagan Singh; Chu, Min-Ching; Wu, Chung-Shu; Ravipati, Srikanth; Ko, Fu-Hsiang

    2011-08-01

    Fully flexible metal-insulator-metal (MIM) capacitors fabricated on 25 microm thin polyimide (PI) substrates via the surface sol-gel process using 10-nm-thick zirconium-silicate (ZrSixOy) and hafnium-silicate (HfSimOn) films as gate dielectrics. The surface morphology of the ZrSixOy and HfSimOn films were investigated using atomic force microscopy and scanning electron microscopy, which confirmed that continuous and crack-free surface growth had occurred on the PI. Both the films treated with oxygen (O2) plasma and annealing (ca. 250 degrees C) consisted of amorphous phase; confirmed by X-ray diffraction. We employed X-ray photoelectron spectroscopy (XPS) at high resolution to examine the chemical composition of the films subjected to various treatment conditions. The shift of the XPS peaks towards higher binding energy revealed the O2 plasma-pretreatment followed by annealing was the most effective process to the surface oxidation at relatively low-temperature, for further passivate the grease traps and making dielectric films thermally stable. The ZrSixOy and HfSimOn films in sandwich-like MIM configuration on the PI substrates exhibited the low leakage current densities of 7.1 x 10(-9) and 8.4 x 10(-9) A/cm2 at applied electric field of 10 MV/cm and maximum capacitance densities of 7.5 and 5.3 fF/microm2 at 1 MHz, respectively. In addition, the ZrSixOy and HfSimOn films in MIM capacitors showed the estimated dielectric constants of 8.2 and 6.0, respectively. Prior to use of flexible MIM capacitors in advanced flexible electronic devices; the reliability test was studied by applying day-dependent leakage current density measurements up to 30 days. These films of silicate-surfactant mesostructured materials have special interest to be used as gate dielectrics in future for flexible metal-oxide-semiconductor devices.

  14. Influence of electrostatic charging on the magnetic and other physical properties of thin metallic films

    Energy Technology Data Exchange (ETDEWEB)

    Steinbeck, K.

    1971-01-01

    Electrical, superconducting and optical properties of thin metal films can be influenced by electrostatic charging. In the same way attempts have been made to change the saturation magnetization of ferromagnetic films, which was measured, e.g., with the torque method. Using the film as one plate of a capacitor torque changes are measured for different voltages. The torque changes are assumed to be caused by magnetization changes due to an altered electron concentration of the metal. The contribution of one unit charge to the magnetic moment was estimated to ca. /sup 1///sub 2/ mu/sub B/.

  15. SM and ND Substiturions in YBCO Films Produced through Metal Organic Deposition (Postprint)

    Science.gov (United States)

    2012-02-01

    AFRL-RZ-WP-TP-2012-0122 SM AND ND SUBSTITUTIONS IN YBCO FILMS PRODUCED THROUGH METAL ORGANIC DEPOSITION (POSTPRINT) B.C. Harrison, J...Paper Postprint 01 January 2004 – 01 January 2006 4. TITLE AND SUBTITLE SM AND ND SUBSTITUTIONS IN YBCO FILMS PRODUCED THROUGH METAL ORGANIC...0223; Clearance Date: 06 Dec 2006. 14. ABSTRACT Epitaxial YBa2Cu3O7-x ( YBCO ) films were produced on non-buffered (100) single crystal LaAlO3 using

  16. Resonance-like Goos-Haenchen shift induced by nano-metal films

    Energy Technology Data Exchange (ETDEWEB)

    Gruschinski, R.; Stahlhofen, A.A. [Institut fuer Integrierte Naturwissenschaften, Universitaet Koblenz (Germany); Nimtz, G. [II. Physikalisches Institut, Universitaet zu Koeln (Germany)

    2008-12-15

    The influence of nano-metal films on the Goos-Haenchen shift (GHS) is investigated. The films were deposited at the total reflecting surface of a perspex prism and had a sheet resistance varying between Z{sub {open_square}}=25 and 3000 {omega}. A resonance-like enhancement of the shift and of the absorption is found for TE polarized waves, when the sheet resistance approached the value of the vacuum impedance. For TM waves the influence of the metal films on the GHS was marginal. The experiments were carried out with microwaves. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  17. Electrodeposition and electrochemical reduction of epitaxial metal oxide thin films and superlattices

    Science.gov (United States)

    He, Zhen

    The focus of this dissertation is the electrodeposition and electrochemical reduction of epitaxial metal oxide thin films and superlattices. The electrochemical reduction of metal oxides to metals has been studied for decades as an alternative to pyrometallurgical processes for the metallurgy industry. However, the previous work was conducted on bulk polycrystalline metal oxides. Paper I in this dissertation shows that epitaxial face-centered cubic magnetite (Fe3O4 ) thin films can be electrochemically reduced to epitaxial body-centered cubic iron (Fe) thin films in aqueous solution on single-crystalline Au substrates at room temperature. This technique opens new possibilities to produce special epitaxial metal/metal oxide heterojunctions and a wide range of epitaxial metallic alloy films from the corresponding mixed metal oxides. Electrodeposition, like biomineralization, is a soft solution processing method which can produce functional materials with special properties onto conducting or semiconducting solid surfaces. Paper II in this dissertation presents the electrodeposition of cobalt-substituted magnetite (CoxFe3-xO4, 0 of cobalt-substituted magnetite (CoxFe3-xO4, 0films and superlattices on Au single-crystalline substrates, which can be potentially used in spintronics and memory devices. Paper III in this dissertation reports the electrodeposition of crystalline cobalt oxide (Co3O4) thin films on stainless steel and Au single-crystalline substrates. The crystalline Co3O4 thin films exhibit high catalytic activity towards the oxygen evolution reaction in an alkaline solution. A possible application of the electrodeposited Co 3O4 is the fabrication of highly active and low-cost photoanodes for photoelectrochemical water-splitting cells.

  18. Effect of contact metals on the piezoelectric properties of aluminum nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Harman, J.; Kabulski, A.; Pagán, V. R.; Famouri, P.; Kasarla, K. R.; Rodak, L. E.; Peter Hensel, J.; Korakakis, D.

    2008-01-01

    The converse piezoelectric response of aluminum nitride evaluated using standard metal insulator semiconductor structures has been found to exhibit a linear dependence on the work function of the metal used as the top electrode. The apparent d33 of the 150–1100 nm films also depends on the dc bias applied to the samples.

  19. Effect of contact metals on the piezoelectric properties of aluminum nitride thin films

    Energy Technology Data Exchange (ETDEWEB)

    Harman, J.P.; Kabulski, A. (West Virginia U., Morgantown, WV); Pagan, V.R. (West Virginia U., Morgantown, WV); Famouri, K. (West Virginia U., Morgantown, WV); Kasarla, K.R.; Rodak, L.E. (West Virginia U., Morgantown, WV); Hensel, J.P.; Korakakis, D.

    2008-07-01

    The converse piezoelectric response of aluminum nitride evaluated using standard metal insulator semiconductor structures has been found to exhibit a linear dependence on the work function of the metal used as the top electrode. The apparent d33 of the 150–1100 nm films also depends on the dc bias applied to the samples.

  20. Relaxation between electrons and surface phonons of a homogeneously photoexcited metal film

    Indian Academy of Sciences (India)

    Navinder Singh

    2004-11-01

    The energy relaxation between the hot degenerate electrons of a homogeneously photoexcited metal film and the surface phonons (phonon wave vectors in two dimensions) is considered under Debye approximation. The state of electrons and phonons is described by equilibrium Fermi and Bose functions with different temperatures. Two cases for electron scattering by the metal surface, namely specular and diffuse scattering, are considered.

  1. Electrically induced reorganization phenomena of liquid metal film printed on biological skin

    Science.gov (United States)

    Guo, Cangran; Yi, Liting; Yu, Yang; Liu, Jing

    2016-12-01

    Liquid metal has been demonstrated to be directly printable on biological skin as physiological measurement elements. However, many fundamental issues remained unclear so far. Here, we disclosed an intriguing phenomenon of electrically induced reorganization of liquid metal film. According to the experiments, when applying an external electric field to liquid metal films which were spray printed on biological skin, it would induce unexpected transformations of the liquid metals among different morphologies and configurations. These include shape shift from a large liquid metal film into a tiny sphere and contraction of liquid metal pool into spherical one. For comprehensively understanding the issues, the impacts of the size, voltage, orientations of the liquid metal electrodes, etc., were clarified. Further, effects of various substrates such as in vitro skin and in vivo skin affecting the liquid metal transformations were experimentally investigated. Compared to the intact tissues, the contraction magnitude of the liquid metal electrode appears weaker on in vivo skin of nude mice under the same electric field. The mechanisms lying behind such phenomena were interpreted through theoretical modeling. Lastly, typical applications of applying the current effect into practical elements such as electrical gating devices were also illustrated as an example. The present findings have both fundamental and practical values, which would help design future technical strategies in fabricating electronically controlled liquid metal electronics on skin.

  2. Biocompatibility evaluation of sputtered zirconium-based thin film metallic glass-coated steels

    Directory of Open Access Journals (Sweden)

    Subramanian B

    2015-10-01

    Full Text Available Balasubramanian Subramanian,1 Sundaram Maruthamuthu,2 Senthilperumal Thanka Rajan1 1Electrochemical Material Science Division, 2Corrosion and Materials Protection Division, Central Electrochemical Research Institute, Karaikudi, India Abstract: Thin film metallic glasses comprised of Zr48Cu36Al8Ag8 (at.% of approximately 1.5 µm and 3 µm in thickness were prepared using magnetron sputtering onto medical grade 316L stainless steel. Their structural and mechanical properties, in vitro corrosion, and antimicrobial activity were analyzed. The amorphous thin film metallic glasses consisted of a single glassy phase, with an absence of any detectable peaks corresponding to crystalline phases. Elemental composition close to the target alloy was noted from EDAX analysis of the thin film. The surface morphology of the film showed a smooth surface on scanning electron microscopy and atomic force microscopy. In vitro electrochemical corrosion studies indicated that the zirconium-based metallic glass could withstand body fluid, showing superior resistance to corrosion and electrochemical stability. Interactions between the coated surface and bacteria were investigated by agar diffusion, solution suspension, and wet interfacial contact methods. The results indicated a clear zone of inhibition against the growth of microorganisms such as Escherichia coli and Staphylococcus aureus, confirming the antimicrobial activity of the thin film metallic glasses. Cytotoxicity studies using L929 fibroblast cells showed these coatings to be noncytotoxic in nature. Keywords: thin film metallic glasses, sputtering, biocompatibility, corrosion, antimicrobial activity

  3. Micro-layers of polystyrene film preventing metal oxidation: implications in cultural heritage conservation

    Science.gov (United States)

    Giambi, Francesca; Carretti, Emiliano; Dei, Luigi; Baglioni, Piero

    2014-12-01

    Protection of surfaces directly exposed to the detrimental action of degradative agents (i.e. oxygen, air pollutants and bacteria) is one of the most important challenges in the field of conservation of works of art. Metallic objects are subjected to specific surface corrosion phenomena that, over the years, make mandatory the research of innovative materials that should avoid the direct contact between the metal surface and the weathering agents. In this paper, the set-up, characterisation and application of a new reversible material for preserving metal artefacts are reported. Micro-layers constituted of low-adhesive polystyrene (PS) films obtained from recycling waste packaging materials made of expanded PS were studied. The morphology and thickness of PS films were characterised by optical, atomic force and scanning electron microscopy (SEM). A further check on thickness was carried out by means of visible spectrophotometry doping the films with a hydrophobic dye. Thermal properties of the PS micro-layers were studied by means of differential scanning calorimetry coupled with optical microscopy. Permeability of the PS films to water vapour was also determined. The potential of the low-adhesive PS films, that enabled an easy removal in case of film deterioration, for preventing metal oxidation was investigated on brass specimens by simulating standard artificial corrosion programmes. Morphological and chemical (coupling the energy-dispersive X-rays spectrometry to SEM measurements) analyses carried out on these metal samples showed promising results in terms of surface protection against corrosion.

  4. Laser cleaning of the metallic thin films from silicon wafer surface with UV laser radiation

    Science.gov (United States)

    Apostol, Ileana; Apostol, Dan; Victor, Damian; Timcu, Adrian; Iordache, Iuliana; Castex, Marie-Claude C.; Galli, Roberta; Ulieru, Dumitru G.

    2004-10-01

    The interest to use laser surface processing in microtechnology as a friendly method from the technologic and environmental point of view lead our studies about laser radiation interaction with photo-resist and metallic thin films. In this view we have tried in our experiments to process metallic thin films deposited on silicon substrate by using laser radiation. To obtain a good quality of the metallic thin film removal from the silicon surface a careful selection of the incident laser intensity, number of pulses and irradiation geometry is needed. The threshold value for the laser cleaning intensity depends on the number of incident laser pulses. A careful experimental estimation of the cleaning conditions from the point of view of incident laser energy, fluence, intensity and irradiation geometry was realized for aluminum, copper, and chromium thin films.

  5. Detection of heavy metals in water using dye nano-complexants and a polymeric film.

    Science.gov (United States)

    Hadar, Hodayah Abuhatzira; Bulatov, Valery; Dolgin, Bella; Schechter, Israel

    2013-09-15

    An optical analytical method, based on complexation reactions of organic azo-dyes with heavy metals, is proposed. It is based on a specially designed polymeric film that when submerged in water contaminated with heavy metals it changes its color. The azo-dyes are injected into the tested water, resulting in formation of nano-particles of insoluble complexes. The polymeric film embeds and dissolves these nano-particles and thus allows for spectral and/or visual analysis. This film consists of a PVC polymeric skeleton and an organic solvent, bis(2-ethylhexyl)phthalate, which possesses high affinity to the heavy metal nano-complexes. The method was exemplified for Cd, Ni and Co ions. The method is sensitive in the sub-ppm range. The mechanism and kinetics of the film coloration were reported.

  6. Synthesis of tunable plasmonic metal-ceramic nanocomposite thin films by temporally modulated sputtered fluxes

    Science.gov (United States)

    Magnfält, D.; Melander, E.; Boyd, R. D.; Kapaklis, V.; Sarakinos, K.

    2017-05-01

    The scientific and technological interest for metal-dielectric nanocomposite thin films emanates from the excitation of localized surface plasmon resonances (LSPRs) on the metal component. The overall optical response of the nanocomposite is governed by the refractive index of the dielectric matrix and the properties of the metallic nanoparticles in terms of their bulk optical properties, size, and shape, and the inter-particle distance of separation. In order to tune the film morphology and optical properties, complex synthesis processes which include multiple steps—i.e., film deposition followed by post-deposition treatment by thermal or laser annealing—are commonly employed. In the present study, we demonstrate that the absorption resonances of Ag/AlOxNy nanocomposite films can be effectively tuned from green (˜2.4 eV) to violet (˜2.8 eV) using a single-step synthesis process that is based on modulating the arrival pattern of film forming species with sub-monolayer resolution, while keeping the amount of Ag in the films constant. Our data indicate that the optical response of the films is the result of LSPRs on isolated Ag nanoparticles that are seemingly shifted by dipolar interactions between neighboring particles. The synthesis strategy presented may be of relevance for enabling integration of plasmonic nanocomposite films on thermally sensitive substrates.

  7. Measurement of interfacial toughness of metal film wire and polymer membrane through electricity induced buckling method.

    Science.gov (United States)

    Wang, Qinghua; Xie, Huimin; Lu, Jian; Chen, Pengwan; Zhang, Qingming

    2011-06-15

    Measurement of interfacial toughness of a metal film wire and a flexible substrate is a challenging issue for evaluating the interfacial bonding capacity of the film-wire/substrate systems. In this paper, an electricity induced buckling method is proposed to measure the interfacial toughness between a metal film wire and a polymer membrane, which does not use a pre-existing weak interface. This method relies on causing a buckling driven delamination of the metal film wire from the polymer membrane, by inducing a compressive stress due to electrification of the film wire. For a sort of structure formed by a constantan film wire and a polymer membrane, the current density range under which the buckling of the film wire will emerge is obtained from experiments. The average interfacial toughness of one typical sample is measured to be 31.6 J/m(2). According to the buckling topographies under different current densities, the interfacial toughness of the constantan film wire and the polymer substrate is found to vary from 10 J/m(2) to 60 J/m(2).

  8. Metal-insulator transition in nanocomposite VO{sub x} films formed by anodic electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Tsui, Lok-kun; Lu, Jiwei; Zangari, Giovanni, E-mail: gz3e@virginia.edu [Department of Materials Science and Engineering, University of Virginia, 395 McCormick Rd., Charlottesville, Virginia 22904 (United States); Hildebrand, Helga; Schmuki, Patrik [Department for Materials Science LKO, University of Erlangen-Nuremberg, Martensstr. 7, D-91058 Erlangen (Germany)

    2013-11-11

    The ability to grow VO{sub 2} films by electrochemical methods would open a low-cost, easily scalable production route to a number of electronic devices. We have synthesized VO{sub x} films by anodic electrodeposition of V{sub 2}O{sub 5}, followed by partial reduction by annealing in Ar. The resulting films are heterogeneous, consisting of various metallic/oxide phases and including regions with VO{sub 2} stoichiometry. A gradual metal insulator transition with a nearly two order of magnitude change in film resistance is observed between room temperature and 140 °C. In addition, the films exhibit a temperature coefficient of resistance of ∼ −2.4%/ °C from 20 to 140 °C.

  9. Patterning of Metal Films on Arbitrary Substrates by Using Polydopamine as a UV-Sensitive Catalytic Layer for Electroless Deposition.

    Science.gov (United States)

    Zhao, Lei; Chen, Daqun; Hu, Weihua

    2016-05-31

    Patterning metal films on various substrates is essentially important and yet challenging for developing a wide variety of innovative devices. We herein report a versatile approach to pattern metal (gold, silver, or copper) films on arbitrary substrates by using the bio-inspired polydopamine (PDA) thin film as a UV-sensitive adhesive layer for electroless deposition. The PDA film is able to be formed on virtually any solid surfaces under mild condition, and its rich catechol groups allow for electroless deposition of metal films with high adhesion stability. Upon UV irradiation, spatially selective oxidation of PDA film occurs and the local metal deposition is inhibited, thus facilitating successful patterning of metal films. Considering its versatility and simplicity, this strategy may demonstrate great applications in manufacturing various innovative devices.

  10. Optical Properties of Semiconductor-Metal Composite Thin Films in the Infrared Region

    Science.gov (United States)

    Nagendra, C. L.; Lamb, James L.

    1993-01-01

    Germanium:Silver (Ge:Ag) composite thin films having different concentrations of Ag, ranging from 7% to 40% have been prepared by dc co-sputtering of Ge an Ag and the films' surface morphology and optical properties have been characterized using transmission electron microscopy (TEM) and infrared spectrophotometry. It is seen that while the films containing lower concentrations of Ag have island-like morphology (i.e. Ag particles distributed in a Ge matrix), the higher metallic concentration films tend to have symmetric distribution of Ag and Ge.

  11. Property enchancement of polyimide films by way of the incorporation of lanthanide metal ions

    Science.gov (United States)

    Thompson, David W.

    1993-01-01

    Lanthanide metal ions were incorporated into the polyimide derived from 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 1,3-bis(aminophenoxy) benzene (APB) in an attempt to produce molecular level metal-polymer composites. The lanthanide series of metal ions (including aluminum, scandium, and yttrium) provide discrete and stable metal ions in the 3+ oxidation state. Throughout the series there is a uniform variation in ionic size ranging from 50 pm for aluminum to a maximum of 103.4 pm for cerium and gradually decreasing again to 84.8 pm for lutetium. The high charge-to-size ratio for these ions as well as the ability to obtain large coordination numbers makes them excellent candidates for interacting with the polymer substructure. The distinct lack of solubility of simple lanthanide salts such as the acetates and halides has made it difficult to obtain metal ions distributed in the polymer framework as discrete ions or metal complexes rather than microcomposites of metal clusters. (Lanthanum nitrates are quite soluble, but the presence of the strongly oxidizing nitrate ion leads to serious degradation of the polymer upon thermal curing. This work was successful at extending the range of soluble metals salts by using chelating agents derived from the beta-diketones dipivaloylmethane, dibenzoylmethane, trifluoroacetylacetone, and hexafluoroacetylacetone. Metal acetates which are insoluble in dimethylacetamide dissolve readily in the presence of the diketones. Addition of the polyimide yields a homogeneous resin which is then cast into a clear film. Upon curing clear films were obtained with the dibenzoylmethane and trifluoroacetylacetone ligands. The dipavaloylmethane precipitates the metal during the film casting process, and hexafluoroacetylacetone gives cured films which are deformed and brittle. These clear films are being evaluated for the effect of the metal ions on the coefficient of thermal expansion, resistance to atomic oxygen, and on

  12. Reliability of vibration energy harvesters of metal-based PZT thin films

    Science.gov (United States)

    Tsujiura, Y.; Suwa, E.; Kurokawa, F.; Hida, H.; Kanno, I.

    2014-11-01

    This paper describes the reliability of piezoelectric vibration energy harvesters (PVEHs) of Pb(Zr,Ti)O3 (PZT) thin films on metal foil cantilevers. The PZT thin films were directly deposited onto the Pt-coated stainless-steel (SS430) cantilevers by rf-magnetron sputtering, and we observed their aging behavior of power generation characteristics under the resonance vibration condition for three days. During the aging measurement, there was neither fatigue failure nor degradation of dielectric properties in our PVEHs (length: 13 mm, width: 5.0 mm, thickness: 104 μm) even under a large excitation acceleration of 25 m/s2. However, we observed clear degradation of the generated electric voltage depending on excitation acceleration. The decay rate of the output voltage was 5% from the start of the measurement at 25 m/s2. The transverse piezoelectric coefficient (e31,f) also degraded with almost the same decay rate as that of the output voltage; this indicates that the degradation of output voltage was mainly caused by that of piezoelectric properties. From the decay curves, the output powers are estimated to degrade 7% at 15 m/s2 and 36% at 25 m/s2 if we continue to excite the PVEHs for 30 years.

  13. Microscopic degradation mechanism of polyimide film caused by surface discharge under bipolar continuous square impulse voltage

    Science.gov (United States)

    Luo, Yang; Wu, Guang-Ning; Liu, Ji-Wu; Peng, Jia; Gao, Guo-Qiang; Zhu, Guang-Ya; Wang, Peng; Cao, Kai-Jiang

    2014-02-01

    Polyimide (PI) film is an important type of insulating material used in inverter-fed motors. Partial discharge (PD) under a sequence of high-frequency square impulses is one of the key factors that lead to premature failures in insulation systems of inverter-fed motors. In order to explore the damage mechanism of PI film caused by discharge, an aging system of surface discharge under bipolar continuous square impulse voltage (BCSIV) is designed based on the ASTM 2275 01 standard and the electrical aging tests of PI film samples are performed above the partial discharge inception voltage (PDIV). The chemical bonds of PI polymer chains are analyzed through Fourier transform infrared spectroscopy (FTIR) and the dielectric properties of unaged and aged PI samples are investigated by LCR testers HIOKI 3532-50. Finally, the micro-morphology and micro-structure changes of PI film samples are observed through scanning electron microscopy (SEM). The results show that the physical and chemical effects of discharge cut off the chemical bonds of PI polymer chains. The fractures of ether bond (C—O—C) and imide ring (C—N—C) on the backbone of a PI polymer chain leads to the decrease of molecular weight, which results in the degradation of PI polymers and the generation of new chemical groups and materials, like carboxylic acid, ketone, aldehydes, etc. The variation of microscopic structure of PI polymers can change the orientation ability of polarizable units when the samples are under an AC electric field, which would cause the dielectric constant ɛ to increase and dielectric loss tan δ to decrease. The SEM images show that the degradation path of PI film is initiated from the surface and then gradually extends to the interior with continuous aging. The injection charge could result in the PI macromolecular chain degradation and increase the trap density in the PI polymer bulk.

  14. Birefringence induced polarization-independent and nearly all-angle transparency through a metallic film

    OpenAIRE

    Gao, Dong-Liang; Gao, Lei; Qiu, Cheng-Wei

    2011-01-01

    We propose an birefringence route to perfect electromagnetic (EM) wave tunneling through a metallic film which relies on homogeneous birefringent coatings with moderate and positive parameters only. EM transparency is achieved in such an birefringent-metal-birefringent (BMB) structure for both polarizations and over nearly all incident angles. The stringent restrictions in conventional dielectric-metal-dielectric media, i.e., dielectrics with extremely negative permittivity, high magnetic fie...

  15. Optimization of Continuous Flow Adsorption of Heavy Metal Ions on Continuous System Column by Peganum Harmala Seeds

    Directory of Open Access Journals (Sweden)

    Elhameh Mohammadpour

    2017-01-01

    Full Text Available Background & Aims of the Study: Heavy metals discharge to environment is a worldwide problem growing in scale. When they accumulate in the environment and in food chains, they can profoundly disrupt biological processes. Peganum Harmala Seeds (PHS was used as a bio-sorbent, using a continuous system for removing Pb2+, Co2+, Ni2+ and Cu2+ ions from aqueous solutions. Materials and Methods: PHS was used as adsorbent in adsorption of heavy metals from aqueous solutions. A stock solution of Pb(II, Co(II, Cu (II and Ni (II was prepared and experiments were down in a column as a reactor. The concentration was determined by atomic adsorption spectroscopy. The effect of various parameters such as pH, contact time, heavy metal concentration, ionic strength, particle size and adsorbent dosage on the process was investigated. Langmuir, Frundlich and Temkin isotherms were studied to evaluate of adsorption isotherms. Results: The adsorption efficiency was found to be pH dependent and enhanced by increasing the solution pH. Maximum removal of ions were obtained at pH=4-8. The equilibrium time was attained after 30 min and desorption studies were performed, using diluted HNO3, H2SO4 and HCl solution (1M on adsorbed metal ions from PHS. Results illustrated that adsorbed metal ions could be recovered under acidic conditions. Investigation of the process kinetic was best fitted with pseudo second-order model. Langmuir, Freundlich and Temkin models were tested for describing the equilibrium data. The Langmuir isotherm illustrated the best description of the cobalt and copper adsorption mechanism and Freundlich model describes lead and nickel ions adsorption on PHS. Conclusion: It was found that PHS would be a good adsorbent for removal of heavy metals.

  16. Direct in Situ Conversion of Metals into Metal-Organic Frameworks: A Strategy for the Rapid Growth of MOF Films on Metal Substrates.

    Science.gov (United States)

    Ji, Hoon; Hwang, Sunhyun; Kim, Keonmok; Kim, CheolGi; Jeong, Nak Cheon

    2016-11-30

    The fabrication of metal-organic framework (MOF) films on conducting substrates has demonstrated great potential in applications such as electronic conduction and sensing. For these applications, direct contact of the film to the conducting substrate without a self-assembled monolayer (SAM) is a desired step that must be achieved prior to the use of MOF films. In this report, we propose an in situ strategy for the rapid one-step conversion of Cu metal into HKUST-1 films on conducting Cu substrates. The Cu substrate acts both as a conducting substrate and a source of Cu(2+) ions during the synthesis of HKUST-1. This synthesis is possible because of the simultaneous reaction of an oxidizing agent and a deprotonating agent, in which the former agent dissolves the metal substrate to form Cu(2+) ions while the latter agent deprotonates the ligand. Using this strategy, the HKUST-1 film could not only be rapidly synthesized within 5 min but also be directly attached to the Cu substrate. Based on microscopic studies, we propose a plausible mechanism for the growth reaction. Furthermore, we show the versatility of this in situ conversion methodology, applying it to ZIF-8, which comprises Zn(2+) ions and imidazole-based ligands. Using an I2-filled HKUST-1 film, we further demonstrate that the direct contact of the MOF film to the conducting substrate makes the material more suitable for use as a sensor or electronic conductor.

  17. Thermal analysis of thin multi-layer metal films during femtosecond laser heating

    Science.gov (United States)

    Karakas, A.; Tunc, M.; Camdali, Ü.

    2010-12-01

    Multi-layer metals films are widely used in modern engineering applications such as gold-coated metal mirrors used in high power laser systems. A transient heat flux model is derived to analyze multi-layer metal films under laser heating. The two separate system composed of electrons and the lattice is considered to take into account the electron-lattice interaction. The present model predicted the effects of underlying chromium's thermal properties on temperature rise of the top gold layer. The effects of two adjacent and different metals with different electron-lattice coupling factors are analyzed for the heating mechanism of different lattices. The derived transient model combined with the two different conservation equations for the lattice and electrons are applied for the ultra short-pulse laser heating of a multi-layer film composed of gold and chromium.

  18. Structural Characteristics and Crystallization of Metallic Glass Sputtered Films by Using Zr System Target

    Directory of Open Access Journals (Sweden)

    Katsuyoshi Kondoh

    2008-01-01

    Full Text Available Zr-Al-Ni-Cu thin films were deposited by the radio-frequency sputtering method at low substrate temperature using three kinds of targets: Zr55Al10Ni5Cu30 bulk metallic glass target (α-BMG target, crystallized bulk metallic glass target (c-BMG target, and an elemental composite target composed of each Zr, Al, Ni chips, and Cu plate. XRD profiles of the films prepared when using these targets indicated that all of the films showed amorphous structures. While XRD profiles of the films using α- and c-BMG targets revealed a broad peak of 2θ=38 degree in the same way as the α-BMG target indicating amorphous structures, that of the film using elemental composite targets showed a broad peak of 2θ=42 degree, which is higher compared to the latter material. As a result of annealing the films at various temperatures for 900 seconds, the film using the α-BMG target showed a crystallization temperature of 748 K, higher than that of BMG with 723 K, while the other films had lower crystallization temperatures below 723 K. XRD profiles also indicated that the crystallized compounds of the films were different from those of BMG target.

  19. Stabilisation of late transition metal and noble metal films in hexagonal and body centred tetragonal phases by epitaxial growth

    Energy Technology Data Exchange (ETDEWEB)

    Hueger, E.

    2005-08-26

    In this work ultrathin metallic films with a crystal phase different to their natural bulk structure were produced by hetero-epitaxial growth on metallic substrates. A further aim of this work was to understand the initiation, growth and stability of crystal phase modifications of these films. there exist cases where the films turn beyond the pseudomorphic-growth to a crystal phase different from their natural bulk structure. The present work presents and discusses such a case in addition to the general phenomenon of pseudomorphic-growth. In particular it is shown that metals whose natural phase is face centred cubic (fcc) can be grown in body centred tetragonal (bct) or hexagonal close packed (hcp) phases in the form of thin films on (001) surfaces of appropriate substrates. The growth behavior, electron diffraction analysis, appearance conditions, geometric fit considerations, examples and a discussion of the phase stability of non-covered films and superlattices is given reviewing all epitaxial-systems whose diffraction pattern can be explained by the hexagonal or pseudomorphic bct phase. (orig.)

  20. Dialkyldiselenophosphinato-metal complexes - a new class of single source precursors for deposition of metal selenide thin films and nanoparticles

    Science.gov (United States)

    Malik, Sajid N.; Akhtar, Masood; Revaprasadu, Neerish; Qadeer Malik, Abdul; Azad Malik, Mohammad

    2014-08-01

    We report here a new synthetic approach for convenient and high yield synthesis of dialkyldiselenophosphinato-metal complexes. A number of diphenyldiselenophosphinato-metal as well as diisopropyldiselenophosphinato-metal complexes have been synthesized and used as precursors for deposition of semiconductor thin films and nanoparticles. Cubic Cu2-xSe and tetragonal CuInSe2 thin films have been deposited by AACVD at 400, 450 and 500 °C whereas cubic PbSe and tetragonal CZTSe thin films have been deposited through doctor blade method followed by annealing. SEM investigations revealed significant differences in morphology of the films deposited at different temperatures. Preparation of Cu2-xSe and In2Se3 nanoparticles using diisopropyldiselenophosphinato-metal precursors has been carried out by colloidal method in HDA/TOP system. Cu2-xSe nanoparticles (grown at 250 °C) and In2Se3 nanoparticles (grown at 270 °C) have a mean diameter of 5.0 ± 1.2 nm and 13 ± 2.5 nm, respectively.

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    Jia-Yang Juang

    2016-10-01

    Full Text Available 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.

  3. [Reseach on THz Time Domain Spectrum of Photo-Induced Insulator-Metal Phase Transition of VO₂ Films].

    Science.gov (United States)

    Wang, Chang-lei; Wu, Shuai; Li, Yan-feng; Liu, Bo-wen; Hu, Ming-lie; Chai, Lu; Xing, Qi-rong; Wang, Qing-yue

    2015-11-01

    Vanadium dioxide (VO₂) film will be phase-transitioned from insulator into metal, accompanied with dramatic change on conductivity, which is named as photo-induced insulator-metal phase transition. Such phase transition of VO₂ film has important application potentials in modulators or other functional devices for terahertz waves. In this paper, the transmission spectrum variations before and after the photo-induced insulator-metal phase transition of vanadium dioxide film are investigated, and the phase transition properties in terahertz(THz) region are analyzed. In the experiment, the phase transition of the VO₂ film was induced by a continuous wave (CW) laser source and a femtosecond (fs) laser source, respectively. Obvious changes on the THz waveforms were observed for the both mentioned means of excitation, and the amplitude attenuation, as well as the signal distortion, was intensified with the increase of the impinging optical power. The fast Fourier transform (FFT) spectra of the transmitted THz time-domain signals were analyzed and it was found that the amplitude of the transmitted spectrum decreased synchronously with the increase of the optical power, accompanied with deformation of the spectrum line shape at the same time. The reason was that the macroscopic dielectric properties of the VO₂ film approached gradually to that of a metal as laser power was increased. A parameter, transmission modulation function, was defined in the paper as the amplitude difference between the transmission spectra of the VO₂ film before and after the laser excitation, to describe the dispersivity of the photo-induced phase transition more clearly. From the curve of the transmission modulation function, strong frequency-dependent properties at THz frequencies were found to vary regularly with the incident light power. After furthermore comparison, it was found that, though the insulator-metal phase transition could be trigged by both CW laser source and fs laser

  4. Centimetre-scale micropore alignment in oriented polycrystalline metal-organic framework films via heteroepitaxial growth

    Science.gov (United States)

    Falcaro, Paolo; Okada, Kenji; Hara, Takaaki; Ikigaki, Ken; Tokudome, Yasuaki; Thornton, Aaron W.; Hill, Anita J.; Williams, Timothy; Doonan, Christian; Takahashi, Masahide

    2016-12-01

    The fabrication of oriented, crystalline films of metal-organic frameworks (MOFs) is a critical step toward their application to advanced technologies such as optics, microelectronics, microfluidics and sensing. However, the direct synthesis of MOF films with controlled crystalline orientation remains a significant challenge. Here we report a one-step approach, carried out under mild conditions, that exploits heteroepitaxial growth for the rapid fabrication of oriented polycrystalline MOF films on the centimetre scale. Our methodology employs crystalline copper hydroxide as a substrate and yields MOF films with oriented pore channels on scales that primarily depend on the dimensions of the substrate. To demonstrate that an anisotropic crystalline morphology can translate to a functional property, we assembled a centimetre-scale MOF film in the presence of a dye and showed that the optical response could be switched `ON’ or `OFF’ by simply rotating the film.

  5. Centimetre-scale micropore alignment in oriented polycrystalline metal-organic framework films via heteroepitaxial growth

    Science.gov (United States)

    Falcaro, Paolo; Okada, Kenji; Hara, Takaaki; Ikigaki, Ken; Tokudome, Yasuaki; Thornton, Aaron W.; Hill, Anita J.; Williams, Timothy; Doonan, Christian; Takahashi, Masahide

    2017-03-01

    The fabrication of oriented, crystalline films of metal-organic frameworks (MOFs) is a critical step toward their application to advanced technologies such as optics, microelectronics, microfluidics and sensing. However, the direct synthesis of MOF films with controlled crystalline orientation remains a significant challenge. Here we report a one-step approach, carried out under mild conditions, that exploits heteroepitaxial growth for the rapid fabrication of oriented polycrystalline MOF films on the centimetre scale. Our methodology employs crystalline copper hydroxide as a substrate and yields MOF films with oriented pore channels on scales that primarily depend on the dimensions of the substrate. To demonstrate that an anisotropic crystalline morphology can translate to a functional property, we assembled a centimetre-scale MOF film in the presence of a dye and showed that the optical response could be switched `ON’ or `OFF’ by simply rotating the film.

  6. High Resistive ZnO/Diamond/Si Films Grown via Metal-organic Chemical Vapour Deposition

    Institute of Scientific and Technical Information of China (English)

    YANG Hong-jun; ZHAO Bai-jun; FANG Xiu-jun; DU Guo-tong; LIU Da-li; GAO Chun-xiao; LIU Xi-zhe

    2005-01-01

    Piezoelectric ZnO layers with high resistivity for surface acoustic wave applications were prepared on polycrystalline diamond/Si substrates with (111) orientation via metal-organic chemical vapour deposition.The characteristics of the films were optimized through different growth methods. The comparative study of the X-ray diffraction spectra and scanning electron microscopic images showed that the final-prepared ZnO films were dominantly c-axis oriented. Zn and O elements in the final prepared ZnO films were investigated through X-ray photoelectron spectroscopy. According to the statistical results, the n(Zn)/n(O) ratio is near 1. The Raman scattering was also performed in back scattering configuration. E2 mode was observed for the final films, which indicated that the better quality ZnO films had been obtained. The resistivity of the films was also enhanced via the modification of the growth methods.

  7. Dynamic buckling behavior of thin metal film lines from substrate

    Science.gov (United States)

    Wu, Dan; Xie, Huimin; Wang, Heling; Zhang, Jie; Li, Chuanwei

    2014-10-01

    The dynamic buckling behavior of thin films from substrate is studied in this work. The experimental results show that the buckling morphology of the constantan film lines from the polymer substrate is inconsistent and non-sinusoidal, which is different from the sinusoidal form of the buckling morphology under static loads. The plastic deformation of the film lines results in the non-sinusoidal buckling morphology and residual deformation when unloaded. Finite element modeling results with regard to the plastic dissipation of the constantan film lines reveal that the plastic dissipation suppresses the buckling-driven delaminating under impact loads. This study will give some new perspectives on the buckling behavior of thin film from substrate.

  8. Heteroepitaxial Cu2O thin film solar cell on metallic substrates.

    Science.gov (United States)

    Wee, Sung Hun; Huang, Po-Shun; Lee, Jung-Kun; Goyal, Amit

    2015-11-06

    Heteroepitaxial, single-crystal-like Cu2O films on inexpensive, flexible, metallic substrates can potentially be used as absorber layers for fabrication of low-cost, high-performance, non-toxic, earth-abundant solar cells. Here, we report epitaxial growth of Cu2O films on low cost, flexible, textured metallic substrates. Cu2O films were deposited on the metallic templates via pulsed laser deposition under various processing conditions to study the influence of processing parameters on the structural and electronic properties of the films. It is found that pure, epitaxial Cu2O phase without any trace of CuO phase is only formed in a limited deposition window of P(O2) - temperature. The (00l) single-oriented, highly textured, Cu2O films deposited under optimum P(O2) - temperature conditions exhibit excellent electronic properties with carrier mobility in the range of 40-60 cm(2) V(-1) s(-1) and carrier concentration over 10(16) cm(-3). The power conversion efficiency of 1.65% is demonstrated from a proof-of-concept Cu2O solar cell based on epitaxial Cu2O film prepared on the textured metal substrate.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-30

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

  10. XPS study of thermal and electron-induced decomposition of Ni and Co acetylacetonate thin films for metal deposition

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, Theodor; Warneke, Jonas; Zielasek, Volkmar, E-mail: zielasek@uni-bremen.de; Swiderek, Petra; Bäumer, Marcus [Institut für Angewandte und Physikalische Chemie, Universität Bremen, Postfach 330440, D-28334 Bremen (Germany)

    2016-07-15

    Optimizing thin metal film deposition techniques from metal-organic precursors such as atomic layer deposition, chemical vapor deposition (CVD), or electron beam-induced deposition (EBID) with the help of surface science analysis tools in ultrahigh vacuum requires a contamination-free precursor delivery technique, especially in the case of the less volatile precursors. For this purpose, the preparation of layers of undecomposed Ni(acac){sub 2} and Co(acac){sub 2} was tried via pulsed spray evaporation of a liquid solution of the precursors in ethanol into a flow of nitrogen on a CVD reactor. Solvent-free layers of intact precursor molecules were obtained when the substrate was held at a temperature of 115 °C. A qualitative comparison of thermally initiated and electron-induced precursor decomposition and metal center reduction was carried out. All deposited films were analyzed with respect to chemical composition quasi in situ by x-ray photoelectron spectroscopy. Thermally initiated decomposition yielded higher metal-to-metal oxide ratios in the deposit than the electron-induced process for which ratios of 60:40 and 20:80 were achieved for Ni and Co, resp. Compared to continuous EBID processes, all deposits showed low levels of carbon impurities of ∼10 at. %. Therefore, postdeposition irradiation of metal acetylacetonate layers by a focused electron beam and subsequent removal of intact precursor by dissolution in ethanol or by heating is proposed as electron beam lithography technique on the laboratory scale for the production of the metal nanostructures.

  11. Synchronized metal-ion irradiation as a way to control growth of transition-metal nitride alloy films during hybrid HIPIMS/DCMS co-sputtering

    Science.gov (United States)

    Greczynski, Grzegorz

    2016-09-01

    High-power pulsed magnetron sputtering (HIPIMS) is particularly attractive for growth of transition metal (TM) nitride alloys for two reasons: (i) the high ionization degree of the sputtered metal flux, and (ii) the time separation of metal- and gas-ion fluxes incident at the substrate. The former implies that ion fluxes originating from elemental targets operated in HIPIMS are distinctly different from those that are obtained during dc magnetron sputtering (DCMS), which helps to separate the effects of HIPIMS and DCMS metal-ion fluxes on film properties. The latter feature allows one to minimize compressive stress due to gas-ion irradiation, by synchronizing the pulsed substrate bias with the metal-rich-plasma portion of the HIPIMS pulse. Here, we use pseudobinary TM nitride model systems TiAlN, TiSiN, TiTaN, and TiAlTaN to carry out experiments in a hybrid configuration with one target powered by HIPIMS, the other operated in DCMS mode. This allows us to probe the roles of intense and metal-ion fluxes (n = 1 , 2) from HIPIMS-powered targets on film growth kinetics, microstructure, and physical properties over a wide range of M1M2N alloy compositions. TiAlN and TiSiN mechanical properties are shown to be determined by the average metal-ion momentum transfer per deposited atom. Irradiation with lighter metal-ions (M1 =Al+ or Si+ during M1-HIPIMS/Ti-DCMS) yields fully-dense single-phase cubic Ti1-x (M1)x N films. In contrast, with higher-mass film constituent ions such as Ti+, easily exceeds the threshold for precipitation of second phase w-AlN or Si3N4. Based on the above results, a new PVD approach is proposed which relies on the hybrid concept to grow dense, hard, and stress-free thin films with no external heating. The primary targets, Ti and/or Al, operate in DCMS mode providing a continuous flux of sputter-ejected metal atoms to sustain a high deposition rate, while a high-mass target metal, Ta, is driven by HIPIMS to serve as a pulsed source of energetic

  12. Preparation and Application of Film Sensor for Metal Structure Crack Monitoring

    Directory of Open Access Journals (Sweden)

    Bo HOU

    2015-11-01

    Full Text Available A crack monitoring technique is desired to ensure the safety and reliability of metallic structures. In the present study, a conductive film sensor was presented to monitor structural cracks in metal structures in real-time based on the electrical potential method. First, a Ti/TiN film sensor was prepared on the fatigue critical portion of a 2A12-T4 aluminum alloy specimen by vacuum ion plating technology, which allows firm integration with the metal surface. A finite element model (FEM of the Ti/TiN film sensor was then constructed and the changes in the output of the sensor along with corresponding changes in crack propagation were discussed. The results indicated that the Ti/TiN film sensor has high sensitivity to cracks and it is feasible to monitor structural surface cracks using the sensor. Finally, crack monitoring experiments were carried out based on the Ti/TiN film sensor. Experimental results showed that the output potential curve of the Ti/TiN film sensor contained several regions, which corresponded to plastic deformation accumulation, crack propagation, and sensor failure, respectively. Therefore, the information on the origination and propagation of structural cracks can be gained through analyzing changes in slope of the output potential values of the Ti/TiN film sensor with respect to time.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9623

  13. Electrochemical and Antimicrobial Properties of Diamondlike Carbon-Metal Composite Films

    Energy Technology Data Exchange (ETDEWEB)

    MORRISON, M. L.; BUCHANAN, R. A.; LIAW, P. K.; BERRY, C. J.; BRIGMON, R.; RIESTER, L.; JIN, C.; NARAYAN, R. J.

    2005-05-11

    Implants containing antimicrobial metals may reduce morbidity, mortality, and healthcare costs associated with medical device-related infections. We have deposited diamondlike carbon-silver (DLC-Ag), diamondlike carbon-platinum (DLC-Pt), and diamondlike carbon-silver-platinum (DLC-AgPt) thin films using a multicomponent target pulsed laser deposition process. Transmission electron microscopy of the DLC-silver and DLC-platinum composite films revealed that the silver and platinum self-assemble into nanoparticle arrays within the diamondlike carbon matrix. The diamondlike carbon-silver film possesses hardness and Young's modulus values of 37 GPa and 331 GPa, respectively. The diamondlike carbon-metal composite films exhibited passive behavior at open-circuit potentials. Low corrosion rates were observed during testing in a phosphate-buffered saline (PBS) electrolyte. In addition, the diamondlike carbon-metal composite films were found to be immune to localized corrosion below 1000 mV (SCE). DLC-silver-platinum films demonstrated exceptional antimicrobial properties against Staphylococcus bacteria. It is believed that a galvanic couple forms between platinum and silver, which accelerates silver ion release and provides more robust antimicrobial activity. Diamondlike carbon-silver-platinum films may provide unique biological functionalities and improved lifetimes for cardiovascular, orthopaedic, biosensor, and implantable microelectromechanical systems.

  14. Morphology and mechanisms of picosecond ablation of metal films on fused silica substrates

    Science.gov (United States)

    Bass, Isaac L.; Negres, Raluca A.; Stanion, Ken; Guss, Gabe; Keller, Wesley J.; Matthews, Manyalibo J.; Rubenchik, Alexander M.; Yoo, Jae Hyuck; Bude, Jeffrey D.

    2016-12-01

    The ablation of magnetron sputtered metal films on fused silica substrates by a 1053 nm, picosecond class laser was studied as part of a demonstration of its use for in-situ characterization of the laser spot under conditions commonly used at the sample plane for laser machining and damage studies. Film thicknesses were 60 and 120 nm. Depth profiles and SEM images of the ablation sites revealed several striking and unexpected features distinct from those typically observed for ablation of bulk metals. Very sharp thresholds were observed for both partial and complete ablation of the films. Partial film ablation was largely independent of laser fluence with a surface smoothness comparable to that of the unablated surface. Clear evidence of material displacement was seen at the boundary for complete film ablation. These features were common to a number of different metal films including Inconel on commercial neutral density filters, stainless steel, and aluminum. We will present data showing the morphology of the ablation sites on these films as well as a model of the possible physical mechanisms producing the unique features observed.

  15. Swift heavy ion irradiation of metal containing tetrahedral amorphous carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Karaseov, P.A., E-mail: platon.karaseov@spbstu.ru [Peter the Great St. Petersburg Polytechnic University, St. Petersburg (Russian Federation); Protopopova, V.S. [Aalto University, Espoo (Finland); Karabeshkin, K.V.; Shubina, E.N.; Mishin, M.V. [Peter the Great St. Petersburg Polytechnic University, St. Petersburg (Russian Federation); Koskinen, J. [Aalto University, Espoo (Finland); Mohapatra, S. [Guru Gobind Singh Indraprastha University, New Delhi (India); Tripathi, A. [Inter University Accelerator Center, New Delhi (India); Avasthi, D.K. [Amity University, Noida 201313, Uttar Pradesh (India); Titov, A.I. [Peter the Great St. Petersburg Polytechnic University, St. Petersburg (Russian Federation)

    2016-07-15

    Highlights: • ta-C films with Ni and Cu doping were grown using dual cathode filtered vacuum arc deposition. • Conductive channels were found in the films by C-AFM after irradiation with 100 MeV Ag ions. • SEM contrast found after irradiation strongly depends on kind of metal impurity in the film. • Different chemical effect of Ni and Cu on transformation of carbon matrix under irradiation was revealed. - Abstract: Thin carbon films were grown at room temperature on (0 0 1) n-Si substrate using dual cathode filtered vacuum arc deposition system. Graphite was used as a source of carbon atoms and separate metallic electrode was simultaneously utilized to introduce Ni or Cu atoms. Films were irradiated by 100 MeV Ag{sup 7+} ions to fluences in the range 1 × 10{sup 10}–3 × 10{sup 11} cm{sup −2}. Rutherford backscattering spectroscopy, Raman scattering, scanning electron microscopy and atomic force microscopy in conductive mode were used to investigate film properties and structure change under irradiation. Some conductive channels having metallic conductivity type were found in the films. Number of such channels is less than number of impinged ions. Presence of Ni and Cu atoms increases conductivity of those conductive channels. Fluence dependence of all properties studied suggests different mechanisms of swift heavy ion irradiation-induced transformation of carbon matrix due to different chemical effect of nickel and copper atoms.

  16. Friction Properties of Polished Cvd Diamond Films Sliding against Different Metals

    Science.gov (United States)

    Lin, Zichao; Sun, Fanghong; Shen, Bin

    2016-11-01

    Owing to their excellent mechanical and tribological properties, like the well-known extreme hardness, low coefficient of friction and high chemical inertness, chemical vapor deposition (CVD) diamond films have found applications as a hard coating for drawing dies. The surface roughness of the diamond films is one of the most important attributes to the drawing dies. In this paper, the effects of different surface roughnesses on the friction properties of diamond films have been experimentally studied. Diamond films were fabricated using hot filament CVD. The WC-Co (Co 6wt.%) drawing dies were used as substrates. A gas mixture of acetone and hydrogen gas was used as the feedstock gas. The CVD diamond films were polished using mechanical polishing. Polished diamond films with three different surface roughnesses, as well as the unpolished diamond film, were fabricated in order to study the tribological performance between the CVD diamond films and different metals with oil lubrication. The unpolished and polished CVD diamond films are characterized with scanning electron microscope (SEM), atomic force microscope (AFM), surface profilometer, Raman spectrum and X-ray diffraction (XRD). The friction examinations were carried out by using a ball-on-plate type reciprocating friction tester. Low carbide steel, stainless steel, copper and aluminum materials were used as counterpart balls. Based on this study, the results presented the friction coefficients between the polished CVD films and different metals. The friction tests demonstrate that the smooth surface finish of CVD diamond films is beneficial for reducing their friction coefficients. The diamond films exhibit low friction coefficients when slid against the stainless steel balls and low carbide steel ball, lower than that slid against copper ball and aluminum ball, attributed to the higher ductility of copper and aluminum causing larger amount of wear debris adhering to the sliding interface and higher adhesive

  17. [Continuous biosynthesis of epoxypropane in a methanotrophic attached-films reactor].

    Science.gov (United States)

    Xin, Jia-Ying; Cui, Jun-Ru; Chen, Jian-Bo; Li, Shu-Ben; Xia, Chun-Gu

    2002-01-01

    Using a fluidized bed as immobilization system, mixed culture methanotrophic attached-films were developed on diatomite particles. The Methane Monooxygenase (MMO) activity was found to increase obviously as soon as the lag phase ended. Greater than 90% of the MMO activity in the bed was attached. Biofilm concentration of 3.3-3.7 mg dry weight cell/g DS was observed. Batch experiments were performed to explore the possibility of producing epoxypropane by a cooxidation process. The effect of methane on the oxidation of propene to epoxypropane and the effect of propene on the growth of methanotroph were also studied. In continuous experiments, optimum mixed gaseous substrates (methane: 35%; propene: 20%; oxygen: 45%) were continuously circulated through the fluidized bed reactor to remove product. Initial epoxypropane productivity was 110-150 mumol/d. The bioreactor operated continuously for 25 d without obvious loss of epoxypropane productivity.

  18. Coupling effects in bilayer thick metal films perforated with rectangular nanohole arrays

    Directory of Open Access Journals (Sweden)

    Li Yuan

    2013-09-01

    Full Text Available The coupling effects in bilayer thick metal (silver films perforated with rectangular nanohole arrays are investigated using the finite-difference time-domain technique. Many interesting light phenomena are observed as the distance between the metal rectangular nanohole arrays varies. Coupling effects are found to play very important roles on the optical and electronic properties of bilayer metal rectangular nanohole arrays: antisymmetric coupling between surface plasmon polaritons near the top and bottom film plane, and antisymmetric coupling between localized surface plasmon resonances near the two long sides of the rectangular hole, are probably excited in each layer of bilayer metal rectangular nanohole arrays; antisymmetric and symmetric magnetic coupling probably occur between the metal rectangular nanohole arrays.

  19. Back contact to film silicon on metal for photovoltaic cells

    Science.gov (United States)

    Branz, Howard M.; Teplin, Charles; Stradins, Pauls

    2013-06-18

    A crystal oriented metal back contact for solar cells is disclosed herein. In one embodiment, a photovoltaic device and methods for making the photovoltaic device are disclosed. The photovoltaic device includes a metal substrate with a crystalline orientation and a heteroepitaxial crystal silicon layer having the same crystal orientation of the metal substrate. A heteroepitaxial buffer layer having the crystal orientation of the metal substrate is positioned between the substrate and the crystal silicon layer to reduce diffusion of metal from the metal foil into the crystal silicon layer and provide chemical compatibility with the heteroepitaxial crystal silicon layer. Additionally, the buffer layer includes one or more electrically conductive pathways to electrically couple the crystal silicon layer and the metal substrate.

  20. Interaction of laser radiation with metal island films

    Science.gov (United States)

    Benditskii, A. A.; Viduta, L. V.; Ostranitsa, A. P.; Tomchuk, P. M.; Iakovlev, V. A.

    1986-08-01

    The emission phenomena arising during the interaction of pulsed laser emission with island films are examined with reference to experimental results obtained for island films of gold irradiated by a CO2 laser at a wavelength of 10.6 microns. Well reproducible emission pulses that are also accompanied by light pulses are produced at intensities less than 10 to the 5th W/sq cm, with the film structure remaining unchanged. The maximum energy of the electrons emitted under the effect of laser radiation is estimated at 3 eV; the work function is 2.1 eV.

  1. Pulsed laser deposition of YBCO films on ISD MgO buffered metal tapes

    CERN Document Server

    Ma, B; Koritala, R E; Fisher, B L; Markowitz, A R; Erck, R A; Baurceanu, R; Dorris, S E; Miller, D J; Balachandran, U

    2003-01-01

    Biaxially textured magnesium oxide (MgO) films deposited by inclined-substrate deposition (ISD) are desirable for rapid production of high-quality template layers for YBCO-coated conductors. High-quality YBCO films were grown on ISD MgO buffered metallic substrates by pulsed laser deposition (PLD). Columnar grains with a roof-tile surface structure were observed in the ISD MgO films. X-ray pole figure analysis revealed that the (002) planes of the ISD MgO films are tilted at an angle from the substrate normal. A small full-width at half maximum (FWHM) of approx 9deg was observed in the phi-scan for ISD MgO films deposited at an inclination angle of 55deg . In-plane texture in the ISD MgO films developed in the first approx 0.5 mu m from the substrate surface, and then stabilized with further increases in film thickness. Yttria-stabilized zirconia and ceria buffer layers were deposited on the ISD MgO grown on metallic substrates prior to the deposition of YBCO by PLD. YBCO films with the c-axis parallel to the...

  2. Spectroscopic studies of the interaction of C 60 and C 70 films with metal substrates

    Science.gov (United States)

    Zhao, Wei; Chen, Li-Quan; Li, Yu-Xin; Zhao, Tie-Nan; Huang, Yu-Zhen; Zhang, Zhan-Xiang; Wang, Hui-Tian; Ye, Pei-Xian; Zhao, Zhong-Xian

    1994-09-01

    The interaction of fullerenes C 60 and C 70 films with metal substrates Au, Ag, In and Sn has been studied by UV-visible absorption spectra, IR, Raman, photoluminescence and second-order nonlinear optics. The absorption spectra show new bands for films on Au, Ag, In and Sn film substrates. For C 60 on Au and Ag, new bands appear, peaking at 723 and 566 nm, respectively. For C 60 film on Sn, several new bands are found at 975.4, 1218, 1557, 2000 and 3570 nm in the NIR and IR regions. Raman spectra reveal an additional peak at 350 cm-1 for C 60 film on Au and five new peaks at 350, 532, 564, 1692 and 1850 cm-1 for the film on Sn. An enhancement of the Raman peak intensity is observed in the latter case. A peak blue shift of photoluminescence band from 749 to 735 nm for C 60 on Sn has also been found. Moreover, a second-order nonlinear optics study at 1.06,μm yields a ten times greater secondary harmonic generation signal intensity for C 60 films on Ag than that of Ag, while no signal is observed for C 60 film on glass. For C 70 on Sn, UV absorption bands broaden and new bands are found at 747, 984 and 1738 nm. The above results suggest a structural distortion of C 60 and C 70 molecules, induced by charge transfer from these metals to the molecules.

  3. Optical resonance analysis of reflected long period fiber gratings with metal film overlay

    Science.gov (United States)

    Zhang, Guiju; Cao, Bing; Wang, Chinua; Zhao, Minfu

    2008-11-01

    We present the experimental results of a novel single-ended reflecting surface plasma resonance (SPR) based long period fiber grating (LPFG) sensor. A long period fiber grating sensing device is properly designed and fabricated with a pulsed CO2 laser writing system. Different nm-thick thin metal films are deposited on the fiber cladding and the fiber end facet for the excitation of surface plasma waves (SPWs) and the reflection of the transmission spectrum of the LPFG with doubled interaction between metal-dielectric interfaces of the fiber to enhance the SPW of the all-fiber SPR-LPFG sensing system. Different thin metal films with different thicknesses are investigated. The effect of the excited SPW transmission along the fiber cladding-metal interface with silver and aluminum films is observed. It is found that different thicknesses of the metal overlay show different resonant behaviors in terms of resonance peak situation, bandwidth and energy loss. Within a certain range, thinner metal film shows narrower bandwidth and deeper peak loss.

  4. Conductive metal oxide film for solar energy control

    Energy Technology Data Exchange (ETDEWEB)

    Donley, H.E.

    1980-05-20

    An electroconductive film comprising the oxides of cobalt and nickel in a spinel structure having the formula nico2o4 and having high absorption in the luminous and infrared portions of the solar energy spectrum is disclosed.

  5. Hard X-ray photoemission spectroscopy of transition-metal oxide thin films and interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wadati, H., E-mail: wadati@ap.t.u-tokyo.ac.jp [Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Hongo, Tokyo 113-8656 (Japan); Fujimori, A. [Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2013-10-15

    Highlights: •Photoemission spectroscopy is a powerful technique to study the electronic structures of transition-metal oxides. •Hard X-ray photoemission spectroscopy (HXPES) is a new type of photoemission spectroscopy which can probe bulk states. •HXPES is very suitable for studying oxide thin films such as the composition dependence and the film thickness dependence. -- Abstract: Photoemission spectroscopy is a powerful experimental technique to study the electronic structures of solids, especially of transition-metal oxides. Recently, hard X-ray photoemission spectroscopy (HXPES) has emerged as a more relevant experimental technique to obtain clear information about bulk states. Here, we describe how HXPES can be conveniently applied to study the interesting subjects on oxide thin films such as the composition dependence and the film thickness dependence of the electronic structures and the interfacial electronic structure of multilayers.

  6. Nanocluster metal films as thermoelectric material for radioisotope mini battery unit

    Science.gov (United States)

    Borisyuk, P. V.; Krasavin, A. V.; Tkalya, E. V.; Lebedinskii, Yu. Yu.; Vasiliev, O. S.; Yakovlev, V. P.; Kozlova, T. I.; Fetisov, V. V.

    2016-10-01

    The paper is devoted to studying the thermoelectric and structural properties of films based on metal nanoclusters (Au, Pd, Pt). The experimental results of the study of single nanoclusters' tunneling conductance obtained with scanning tunneling spectroscopy are presented. The obtained data allowed us to evaluate the thermoelectric power of thin film consisting of densely packed individual nanoclusters. It is shown that such thin films can operate as highly efficient thermoelectric materials. A scheme of miniature thermoelectric radioisotope power source based on the thorium-228 isotope is proposed. The efficiency of the radioisotope battery using thermoelectric converters based on nanocluster metal films is shown to reach values up to 1.3%. The estimated characteristics of the device are comparable with the parameters of up-to-date radioisotope batteries based on nickel-63.

  7. Swift heavy ion irradiation of metal containing tetrahedral amorphous carbon films

    Science.gov (United States)

    Karaseov, P. A.; Protopopova, V. S.; Karabeshkin, K. V.; Shubina, E. N.; Mishin, M. V.; Koskinen, J.; Mohapatra, S.; Tripathi, A.; Avasthi, D. K.; Titov, A. I.

    2016-07-01

    Thin carbon films were grown at room temperature on (0 0 1) n-Si substrate using dual cathode filtered vacuum arc deposition system. Graphite was used as a source of carbon atoms and separate metallic electrode was simultaneously utilized to introduce Ni or Cu atoms. Films were irradiated by 100 MeV Ag7+ ions to fluences in the range 1 × 1010-3 × 1011 cm-2. Rutherford backscattering spectroscopy, Raman scattering, scanning electron microscopy and atomic force microscopy in conductive mode were used to investigate film properties and structure change under irradiation. Some conductive channels having metallic conductivity type were found in the films. Number of such channels is less than number of impinged ions. Presence of Ni and Cu atoms increases conductivity of those conductive channels. Fluence dependence of all properties studied suggests different mechanisms of swift heavy ion irradiation-induced transformation of carbon matrix due to different chemical effect of nickel and copper atoms.

  8. Mechanical properties of micron and nanodimentional metal films

    Directory of Open Access Journals (Sweden)

    I.Yu. Protsenko

    2010-01-01

    Full Text Available The mechanical and strain resistivity properties data for bulk condensates and nanodimentional films at the elastic and plastic deformation was analyzed. The experimental results of strain resistivity properties of one-layer (Fe, Cr, Pd and Pt and two-layer (Fe/Cr, Cu/Cr and Pd/Fe films, in particular, dependence of the deformation at the transition from elastic to plastic deformation from thickness was presented.

  9. Doped thin metal oxide films for catalytic gas sensors

    Energy Technology Data Exchange (ETDEWEB)

    Gyoergy, E. [Lasers Department, Institute of Atomic Physics, P.O. Box MG 36, 76900 Bucharest V (Romania)]. E-mail: eniko@ifin.nipne.ro; Axente, E. [Lasers Department, Institute of Atomic Physics, P.O. Box MG 36, 76900 Bucharest V (Romania); Mihailescu, I.N. [Lasers Department, Institute of Atomic Physics, P.O. Box MG 36, 76900 Bucharest V (Romania); Ducu, C. [University of Pitesti, Targul din Vale 1, 110040 Pitesti (Romania); Du, H. [Advanced Materials Research Institute, University of Newcastle (United Kingdom)

    2006-04-30

    TiO{sub 2} and Pt doped TiO{sub 2} thin films were grown by pulsed laser deposition on <0 0 1> SiO{sub 2} substrates. The doped films were compared with undoped ones deposited in similar experimental conditions. An UV KrF* ({lambda} = 248 nm, {tau} {sub FWHM} {approx_equal} 20 ns, {nu} = 2 Hz) excimer laser was used for the irradiation of the TiO{sub 2} or Pt doped TiO{sub 2} targets. The substrate temperatures were fixed during the growth of the thin films at values within the 300-500 deg. Crange. The films' surface morphology was investigated by atomic force microscopy and their crystalline quality by X-ray diffractometry. The corresponding transmission spectra were recorded with the aid of a double beam spectrophotometer in the spectral range of 400-1100 nm. No contaminants or Pt segregation were detected in the synthesized anatase phase TiO{sub 2} thin films composition. Titania crystallites growth inhibition was observed with the increase of the dopant concentration. The average optical transmittance in the visible-infrared spectral range of the films is higher than 85%, which makes them suitable for sensor applications.

  10. Converting surface plasmon polaritons into spatial bending beams through graded dielectric rectangles over metal film

    Science.gov (United States)

    Li, Hui; Xu, Yongzheng; Wang, Gang; Fu, Tong; Wang, Li; Zhang, Zhongyue

    2017-01-01

    Spatial bending beams, which preserve their spatial shape while propagating along curved trajectories in free space, offer important application in the fields of fiber sensor, optical trapping, and micromanipulation. In this work, two slits are designed on a metal film to excite surface plasmon polaritons (SPPs), and a group of dielectric rectangles over metal film is theoretically proposed to directly convert SPPs into spatial beams showing arbitrary bending. The appropriate locations of the dielectric rectangles are calculated by phase-modulation method. Transverse acceleration and nondiffraction characteristics of spatial bending beams are observed. We further demonstrate that the intensity distribution, shape, and propagation length of spatial beams showing arbitrary bending rely on structural parameters of dielectric rectangles and on the distance between dielectric rectangles and metal film. These findings provide guidance in the design and optimization of bending beam generators.

  11. Metal nanodot arrays fabricated via seed-mediated electroless plating with block copolymer thin film scaffolding.

    Science.gov (United States)

    Komiyama, Hideaki; Iyoda, Tomokazu; Sanji, Takanobu

    2015-10-02

    We present an alternative approach to fabricating hexagonally arranged nanodot arrays of various metals by seed-mediated electroless plating with a cylinder-forming block copolymer thin film, PEO-b-PMA(Az), as a scaffold. Metal ions were selectively incorporated into PEO cylinders, followed by their reduction to metal and the etching of the scaffold to obtain highly ordered seed arrays of Au, Pd, and Pt. Nanodot arrays of the target metals (Au, Ag, and Ni) were selectively grown on the seed with their highly ordered arrangement by electroless plating. We studied the fabrication processes' suitability for control of the nanodot array size, as well as the plasmonic properties thereof.

  12. Ethanol-mediated metal transfer printing on organic films.

    Science.gov (United States)

    Aldakov, Dmitry; Tondelier, Denis; Palacin, Serge; Bonnassieux, Yvan

    2011-03-01

    Ethanol-mediated metal transfer printing (mTP) is a soft method, which allows to efficiently deposit metals onto various organic surfaces for applications in organic electronics. This simple approach in based on the stronger adhesion of the metals to the organic materials in the presence of thin ethanol layer between the metallized PDMS and the substrate due to the capillary action. Patterns with a resolution of at least 20 μm have been obtained on organic polymeric materials and photoresists without heating or applied pressure. Compared to other methods ethanol mediated mTP is considerably faster and has smaller limitations on the stamp depth. Residual silicone layer detected on the metal surface after the transfer by XPS studies has been mostly removed by UV/ozone treatment. Organic field-effect transistors (OTFTs) based on the metal electrodes deposited by mTP have been successfully fabricated and tested.

  13. Continuous Electron Doping of Single-Walled Carbon Nanotube Films Using Inkjet Technique

    Science.gov (United States)

    Matsuzaki, Satoki; Nobusa, Yuki; Shimizu, Ryo; Yanagi, Kazuhiro; Kataura, Hiromichi; Takenobu, Taishi

    2012-06-01

    The fabrication of logic circuits using the inkjet technique has attracted especially strong interest owing to wide range applications such as flexible and printed electronics. Although logic circuits fabricated using the inkjet method have already been accomplished, the precise control of gate threshold voltages has not been realized yet. In this study, we have demonstrated electron doping of single-walled carbon nanotube (SWCNT) films by inkjet printing of dilute poly(ethylene imine) (PEI) ink. We have successfully obtained the continuous threshold voltage shift by varying the number of doping steps, indicating that the carrier concentration in PEI ink is much lower than that of our previous work.

  14. Mechanical properties of ultra thin metallic films revealed by synchrotron techniques

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, Patric Alfons

    2007-07-20

    A prerequisite for the study of the scaling behavior of mechanical properties of ultra thin films is a suitable testing technique. Therefore synchrotron-based in situ testing techniques were developed and optimized in order to characterize the stress evolution in ultra thin metallic films on compliant polymer substrates during isothermal tensile tests. Experimental procedures for polycrystalline as well as single crystalline films were established. These techniques were used to systematically investigate the influence of microstructure, film thickness (20 to 1000 nm) and temperature (-150 to 200 C) on the mechanical properties. Passivated and unpassivated Au and Cu films as well as single crystalline Au films on polyimide substrates were tested. Special care was also dedicated to the microstructural characterization of the samples which was very important for the correct interpretation of the results of the mechanical tests. Down to a film thickness of about 100 to 200 nm the yield strength increased for all film systems (passivated and unpassivated) and microstructures (polycrystalline and singlecrystalline). The influence of different interfaces was smaller than expected. This could be explained by a dislocation source model based on the nucleation of perfect dislocations. For polycrystalline films the film thickness as well as the grain size distribution had to be considered. For smaller film thicknesses the increase in flow stress was weaker and the deformation behavior changed because the nucleation of perfect dislocations became unfavorable. Instead, the film materials used alternative mechanisms to relieve the high stresses. For regular and homogeneous deformation the total strain was accommodated by the nucleation and motion of partial dislocations. If the deformation was localized due to initial cracks in a brittle interlayer or local delamination, dislocation plasticity was not effective enough to relieve the stress concentration and the films showed

  15. Continuous Magnetoelectric Control in Multiferroic DyMnO3 Films with Twin-like Domains

    Science.gov (United States)

    Lu, Chengliang; Deniz, Hakan; Li, Xiang; Liu, Jun-Ming; Cheong, Sang-Wook

    2016-02-01

    The magnetic control of ferroelectric polarization is currently a central topic in the multiferroic researches, owing to the related gigantic magnetoelectric coupling and fascinating physics. Although a bunch of novel magnetoelectric effect have been discovered in multiferroics of magnetic origin, the manipulation of polarization was found to be fundamentally determined by the microscopic origin in a certain multiferroic phase, hindering the development of unusual magnetoelectric control. Here, we report emergent magnetoelectric control in DyMnO3/Nb:SrTiO3 (001) films showing twin-like domain structure. Our results demonstrate interesting magnetically induced partial switch of polarization due to the coexistence of polarizations along both the a-axis and c-axis enabled by the twin-like domain structure in DyMnO3 films, despite the polarization-switch was conventionally believed to be a one-step event in the bulk counterpart. Moreover, a continuous and periodic control of macroscopic polarization by an in-plane rotating magnetic field is evidenced in the thin films. This distinctive magnetic manipulation of polarization is the consequence of the cooperative action of the twin-like domains and the dual magnetic origin of polarization, which promises additional applications using the magnetic control of ferroelectricity.

  16. Theoretical study of the transmission properties of a metallic film with surface corrugations

    DEFF Research Database (Denmark)

    Xiao, Sanshui; Qiu, Min

    2007-01-01

    Transmissions through a metallic film at near-infrared wavelengths with different surface corrugations on both sides are systemically studied. The calculations are performed by the three-dimensional finite-different time-domain method. Calculated results show that the transmissions are strongly...... dependent on the surface structures. Compared with other structures, the transmission for a film periodically drilled by cross air grooves are relatively larger. Transmission is enhanced more with symmetric conditions on both layers than the asymmetric case. The enhanced transmission can be explained...... by a competition between the absorption in the metal and enhanced transmission due to coupled surface plasmon resonance....

  17. Negative Goos-H\\"anchen Shifts with Nano-metal-films on Prism Surface

    CERN Document Server

    Rong, Jiang; Gui-Zhen, Lu

    2012-01-01

    In recent years, the fantastic phenomena of negative Goos-H\\"anchen shifts were studied in several optics experiments with the positive refractivity materials, which is predicted by many scientists through both classical physics or quantum physics theory. In order to verify the negative Goos-H\\"anchen shifts phenomena, an experiment in microwave frequency was done with nano-metal-films on prism surface. Because using nano-metal-films enhances self-interference effect, not only were the negative Goos-H\\"anchen shifts obtained, but also the giant Goos-H\\"anchen shifts was appeared.

  18. Electronic hybridisation implications for the damage-tolerance of thin film metallic glasses

    Science.gov (United States)

    Schnabel, Volker; Jaya, B. Nagamani; Köhler, Mathias; Music, Denis; Kirchlechner, Christoph; Dehm, Gerhard; Raabe, Dierk; Schneider, Jochen M.

    2016-01-01

    A paramount challenge in materials science is to design damage-tolerant glasses. Poisson’s ratio is commonly used as a criterion to gauge the brittle-ductile transition in glasses. However, our data, as well as results in the literature, are in conflict with the concept of Poisson’s ratio serving as a universal parameter for fracture energy. Here, we identify the electronic structure fingerprint associated with damage tolerance in thin film metallic glasses. Our correlative theoretical and experimental data reveal that the fraction of bonds stemming from hybridised states compared to the overall bonding can be associated with damage tolerance in thin film metallic glasses. PMID:27819318

  19. Void nucleation in biaxially strained ultrathin films of face-centered cubic metals

    Science.gov (United States)

    Kolluri, Kedarnath; Gungor, M. Rauf; Maroudas, Dimitrios

    2007-05-01

    We report an analysis of void nucleation as a relaxation mechanism in freestanding biaxially strained ultrathin films of face-centered cubic metals based on large-scale molecular-dynamics simulations. Above a critical strain level, multiple threading dislocations are emitted from the film surface. The surface step traces formed by gliding dislocations on intersecting and on adjacent parallel glide planes lead to formation and growth of surface pits and grooves, while vacancies form due to gliding of jogged dislocations and dislocation intersections. Coalescence of the surface pits with vacancy clusters is the precursor to the formation of a larger void extending across the film.

  20. Growing extremely thin bulklike metal film on a semiconductor surface: Monolayer Al(111) on Si(111)

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Ying; Kim, Yong-Hyun; Zhang, S. B.; Ebert, Philipp; Yang, Shenyuan; Tang, Zhe; Wu, Kehui; Wang, E. G.

    2007-10-29

    We report combined scanning tunneling microscopy, x-ray photoelectron emission spectroscopy, electron energy loss spectroscopy, and theoretical study of the growth of ultrathin Al film on the Si(111) substrate. We show that by (i) a modification of the substrate reconstruction with a √3×√3 surface and (ii) a choice of materials with commensurate lattices, atomically flat film can be obtained even at the ultimate one monolayer limit, while maintaining a bulklike atomic structure. Detailed analysis shows that this monolayer Al(111)-1×1Al(111)-1×1 film is electronically decoupled from the Si substrate, and it shows metallic characteristics.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-27

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

  2. Therapy imaging: a signal-to-noise analysis of metal plate/film detectors.

    Science.gov (United States)

    Munro, P; Rawlinson, J A; Fenster, A

    1987-01-01

    We have measured the modulation transfer functions [MTF (f)'s] and the noise power spectra [NPS (f)] of therapy x-ray detectors irradiated by 60Co, 6- and 18-MV radiotherapy beams. Using these quantities, we have calculated the noise-equivalent quanta [NEQ (f)] and the detective quantum efficiency [DQE (f)] to quantitate the limitations of therapy detectors. The detectors consisted of film or fluorescent screen-film combinations in contact with copper, lead, or tungsten metal plates. The resolution of the detectors was found to be comparable to fluorescent screen-film combinations used in diagnostic radiology, however, the signal-to-noise ratio [SNR (f)] of the detectors was limited due to film granularity. We conclude that improved images can be obtained by using alternative detector systems which have less noise or film granularity.

  3. The Size Effect on the Temperature Dependence of the Resistivity of Metal Films

    Directory of Open Access Journals (Sweden)

    L.V. Odnodvorets

    2014-11-01

    Full Text Available The analysis of the temperature dependences of the electrical conductivity of thin metal films is per-formed. It is shown that the size dependence of the effective parameter of the electron-phonon interaction is connected with amplification of high-temperature electron-phonon interaction at the decrease in the film thickness which appears as a result of the shift of the phonon spectrum to higher frequencies. We have found that the slope of the experimental temperature dependences of the resistance for Pd, Pt, and Sc films, as in the case of Mo, Cr, Ag, Au, and PdAu films, according to the data of other authors, increases with the decrease in the thickness. As the film thickness decreases the average phonon energy increases that leads to the increase in the efficiency of the electron-phonon scattering and, finally, to the increase in the resistivity.

  4. Influence of the metal substrate properties on kinetics of zeolite film formation

    Energy Technology Data Exchange (ETDEWEB)

    Valtchev, V.; Mintova, S.; Konstantinov, L. [Institute of Applied Mineralogy, Sofia (Bulgaria)

    1995-12-01

    The main stages of film formation of the zeolites A. Y and silicalite-1 on differently pretreated cooper substrates is considered from the viewpoint of the film morphology. The molecular sieves crystallization on metal substrate. and microporous modules has extensively studied during last years due to their potential in designing chemical sensors, gas separators, catalysts. etc. The gel chemical composition. the substrate surface structure and its position in the reactor influence considerably the zeolite film formation. The kinetics of film formation is by no means a simple subject to study and its detailed characterization requires an optimal choice of parameters. In this work we consider some kinetics aspects of the deposition of films of zeolites A, Y and silicalite-1 on differently pretreated cooper substrates.

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

    Energy Technology Data Exchange (ETDEWEB)

    Krumov, E., E-mail: emodk@clf.bas.bg [Central Laboratory of Photoprocesses ' Acad. Jordan Malinowski' , Bulgarian Academy of Sciences, Acad. Georgy Bonchev Str., bl. 109, 1113 Sofia (Bulgaria); Starbov, N.; Starbova, K. [Central Laboratory of Photoprocesses ' Acad. Jordan Malinowski' , Bulgarian Academy of Sciences, Acad. Georgy Bonchev Str., bl. 109, 1113 Sofia (Bulgaria); Perea, A.; Solis, J. [Instituto de Optica ' Daza de Valdes' , CSIC, 28006 Madrid (Spain)

    2009-11-15

    Excimer laser processing is applied for tailoring the surface morphology and phase composition of CeO{sub 2} ceramic thin films. E-beam evaporation technique is used to deposit samples on stainless steel and silicate glass substrates. The films are then irradiated with ArF* excimer laser pulses under different exposure conditions. Scanning electron microscopy, optical spectrophotometry, X-ray diffractometry and EDS microanalysis are used to characterize the non-irradiated and laser-processed films. Upon UV laser exposure there is large increase of the surface roughness that is accompanied by photo-darkening and ceria reduction. It is shown that the laser induced changes in the CeO{sub 2} films facilitate the deposition of metal nano-aggregates in a commercial copper electroless plating bath. The significance of laser modification as a novel approach for the production of CeO{sub 2} based thin film catalysts is discussed.

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

    Science.gov (United States)

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

    2016-03-01

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

  7. Stabilization of ultrathin (hydroxy)oxide films on transition metal substrates for electrochemical energy conversion

    Science.gov (United States)

    Zeng, Zhenhua; Chang, Kee-Chul; Kubal, Joseph; Markovic, Nenad M.; Greeley, Jeffrey

    2017-06-01

    Design of cost-effective electrocatalysts with enhanced stability and activity is of paramount importance for the next generation of energy conversion systems, including fuel cells and electrolysers. However, electrocatalytic materials generally improve one of these properties at the expense of the other. Here, using density functional theory calculations and electrochemical surface science measurements, we explore atomic-level features of ultrathin (hydroxy)oxide films on transition metal substrates and demonstrate that these films exhibit both excellent stability and activity for electrocatalytic applications. The films adopt structures with stabilities that significantly exceed bulk Pourbaix limits, including stoichiometries not found in bulk and properties that are tunable by controlling voltage, film composition, and substrate identity. Using nickel (hydroxy)oxide/Pt(111) as an example, we further show how the films enhance activity for hydrogen evolution through a bifunctional effect. The results suggest design principles for this class of electrocatalysts with simultaneously enhanced stability and activity for energy conversion.

  8. The growth of thin film epitaxial oxide-metal heterostructures

    CERN Document Server

    Wang, C

    1998-01-01

    films with lowest IR emissivity are those made from the purest targets despite their having comparable roughnesses to films from lower purity targets. The lowest emissivity achieved was in the range of 1.64% to 1.72% measured at 3.8 mu m for 1.5 to 1.8 mu m thick films. Modifications to standard idealized Drude theory have been made which, in a phenomenological way, take account of imperfections in the sputtered Al film, oxidation state and roughness. in electric properties of the Nb film and the reduction in crystalline quality of the MgO layer. The reduction of transition temperature to the superconducting state, Tc, and the similarly systematic increase in the Nb lattice parameter were observed consistent with oxygen content data reported in the literature, as the Nb became heavily oxidized. Examination of the surface of clean and oxidized Nb by atomic force microscopy, and deposition of MgO in UHV onto a previously oxidized Nb surface, suggested that the decrease in crystalline quality of the MgO can be a...

  9. Self-assembly of organic films on a liquid metal

    Science.gov (United States)

    Magnussen, Olaf M.; Ocko, Benjamin M.; Deutsch, Moshe; Regan, Michael J.; Pershan, Peter S.; Abernathy, Douglas; Grübel, Gerhard; Legrand, Jean-François

    1996-11-01

    THE structure and phase behaviour of organic thin films result from the subtle interplay of intermolecular Van der Waals interactions, which promote self-assembly and long-ranged order, and the more complex interactions between the end groups of the organic chains and the substrate. The structure of molecular films of amphiphiles has been extensively studied on subphases of dielectric liquids, notably water (Langmuir mono-layers) and on solid surfaces (self-assembled monolayers, SAMs)1-4. Here we report structural studies, by synchrotron X-ray scattering, of an intermediate case: densely packed alka-nethiol films on the surface of liquid mercury. While, like SAMs, these films form strong chemical bonds to the subphase, this subphase is smooth and unstructured, as in the case of Langmuir monolayers. But unlike either of these1,2,5-7, our films have no in-plane long-range order. We suggest that the strong interaction of the thiol group with the underlying disordered liquid dominates here over the order-promoting interactions of the alkyl chains.

  10. Thickness dependent electronic structure and morphology of rubrene thin films on metal, semiconductor, and dielectric substrates

    Science.gov (United States)

    Sinha, Sumona; Mukherjee, M.

    2013-08-01

    The evolution of the electronic structure and morphology of rubrene thin films on noble-metal, semiconductor and dielectric substrates have been investigated as a function of thickness of deposited films by using photoelectron spectroscopy and atomic force microscopy. The clean polycrystalline Au and Ag were used as noble-metals, whereas, H passivated and SiO2 coated Si (100) were used as semiconductors and dielectric substrates. Discussion and comparison on interface dipole, energy level alignment, and surface morphology for the four cases are presented. The formation of dipole at metallic interfaces is found to occur due to push back effect. S parameter obtained from the variation of barrier height with the change of work function of the contacting metal indicates moderately weak interaction between rubrene and the metal substrates. The thickness dependent energy level alignment of the physisorbed rubrene films on different substrates is explained by a dielectric model in terms of electrostatic screening of photo-holes or photoemission final state relaxation energy. Films on all the substrates are found to grow following Stranski-Krastnov type growth mode and are more ordered at higher coverage.

  11. Chemical resistance of thin film materials based on metal oxides grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Sammelselg, Väino, E-mail: vaino.sammelselg@ut.ee [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia); Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu (Estonia); Netšipailo, Ivan; Aidla, Aleks; Tarre, Aivar; Aarik, Lauri; Asari, Jelena; Ritslaid, Peeter; Aarik, Jaan [Institute of Physics, University of Tartu, Riia 142, 51014 Tartu (Estonia)

    2013-09-02

    Etching rate of technologically important metal oxide thin films in hot sulphuric acid was investigated. The films of Al-, Ti-, Cr-, and Ta-oxides studied were grown by atomic layer deposition (ALD) method on silicon substrates from different precursors in large ranges of growth temperatures (80–900 °C) in order to reveal process parameters that allow deposition of coatings with higher chemical resistance. The results obtained demonstrate that application of processes that yield films with lower concentration of residual impurities as well as crystallization of films in thermal ALD processes leads to significant decrease of etching rate. Crystalline films of materials studied showed etching rates down to values of < 5 pm/s. - Highlights: • Etching of atomic layer deposited thin metal oxide films in hot H{sub 2}SO{sub 4} was studied. • Smallest etching rates of < 5 pm/s for TiO{sub 2}, Al{sub 2}O{sub 3}, and Cr{sub 2}O{sub 3} were reached. • Highest etching rate of 2.8 nm/s for Al{sub 2}O{sub 3} was occurred. • Remarkable differences in etching of non- and crystalline films were observed.

  12. Tensile characteristics of metal nanoparticle films on flexible polymer substrates for printed electronics applications

    Science.gov (United States)

    Kim, Sanghyeok; Won, Sejeong; Sim, Gi-Dong; Park, Inkyu; Lee, Soon-Bok

    2013-03-01

    Metal nanoparticle solutions are widely used for the fabrication of printed electronic devices. The mechanical properties of the solution-processed metal nanoparticle thin films are very important for the robust and reliable operation of printed electronic devices. In this paper, we report the tensile characteristics of silver nanoparticle (Ag NP) thin films on flexible polymer substrates by observing the microstructures and measuring the electrical resistance under tensile strain. The effects of the annealing temperatures and periods of Ag NP thin films on their failure strains are explained with a microstructural investigation. The maximum failure strain for Ag NP thin film was 6.6% after initial sintering at 150 °C for 30 min. Thermal annealing at higher temperatures for longer periods resulted in a reduction of the maximum failure strain, presumably due to higher porosity and larger pore size. We also found that solution-processed Ag NP thin films have lower failure strains than those of electron beam evaporated Ag thin films due to their highly porous film morphologies.

  13. In-situ surface sensitive X-ray investigations of quench condensed thin metal films

    Energy Technology Data Exchange (ETDEWEB)

    Markert, Christian; Luetzenkirchen-Hecht, Dirk; Gertz, Sascha; Frahm, Ronald [Bergische Universitaet Wuppertal, Fachbereich C / Abteilung Physik, Gaussstrasse 20, 42119 Wuppertal (Germany)

    2007-07-01

    We report of ultrahigh vacuum (UHV) experiments on ultra thin Au, Bi and Pb films (thickness less than 10 nm) deposited on atomically flat float-glass substrates which are held at cryogenic temperatures down to 10 K. For deposition temperatures below 100 K the formation of highly disordered or even amorphous metal films can be expected, because thermally activated diffusion of the ad atoms should be inhibited. An UHV chamber was constructed which is suited for grazing incidence X-ray experiments during the quench condensation of the metal films. Various X-ray methods were used for the in-situ investigation of the films growth and their structural evolution with the thickness and an subsequent annealing process. EXAFS (Extended X-ray Absorption Fine Structure) in reflection is used to study the local structure of the films. Furthermore specular and non-specular X-ray reflectivity measurements were performed to get information about the films density and surface roughness parameters (correlation length, hurst parameter etc.). In addition in situ resistivity measurements which are sensitive towards changes of the films microstructure were performed in parallel to the X-ray experiments.

  14. Tensile characteristics of metal nanoparticle films on flexible polymer substrates for printed electronics applications.

    Science.gov (United States)

    Kim, Sanghyeok; Won, Sejeong; Sim, Gi-Dong; Park, Inkyu; Lee, Soon-Bok

    2013-03-01

    Metal nanoparticle solutions are widely used for the fabrication of printed electronic devices. The mechanical properties of the solution-processed metal nanoparticle thin films are very important for the robust and reliable operation of printed electronic devices. In this paper, we report the tensile characteristics of silver nanoparticle (Ag NP) thin films on flexible polymer substrates by observing the microstructures and measuring the electrical resistance under tensile strain. The effects of the annealing temperatures and periods of Ag NP thin films on their failure strains are explained with a microstructural investigation. The maximum failure strain for Ag NP thin film was 6.6% after initial sintering at 150 °C for 30 min. Thermal annealing at higher temperatures for longer periods resulted in a reduction of the maximum failure strain, presumably due to higher porosity and larger pore size. We also found that solution-processed Ag NP thin films have lower failure strains than those of electron beam evaporated Ag thin films due to their highly porous film morphologies.

  15. Continuous renal replacement therapy amino acid, trace metal and folate clearance in critically ill children

    Science.gov (United States)

    We hypothesized that continuous veno-venous hemodialysis (CVVHD) results in amino acid, trace metals, and folate losses, thereby adversely impacting nutrient balance. Critically ill children receiving CVVHD were studied prospectively for 5 days. Blood concentrations, amino acids, copper, zinc, man...

  16. Continuous-wave broadband emitter based on a transition-metal-ion-doped waveguide

    NARCIS (Netherlands)

    Pollnau, M.; Salathé, R.P.; Bhutta, T.; Shepherd, D.P.; Eason, R.W.

    2001-01-01

    We demonstrate the suitability of a simple continuous-wave-pumped transition-metal-ion-doped waveguide as a broadband light source in the wavelength region 600–1000 nm for interferometric applications. Spatially coherent (single mode in the confined direction), spectrally broadband (~130-nm FWHM) lu

  17. Submicron writing by laser irradiation on metal nano-particle dispersed films toward flexible electronics

    Science.gov (United States)

    Watanabe, Akira; Aminuzzaman, Mohammod; Miyashita, Tokuji

    2009-02-01

    The requirement for microwiring technology by a wet process has significantly increased recently toward the achievement of printable and flexible electronics. We have developed the metal microwiring with a resolution higher than 1 μm by the laser direct writing technique using Ag and Cu nano-particle-dispersed films as precursors. The technique was applied to the microwiring on a flexible and transparent polymer film. The metallization is caused in a micro-region by focused laser beam, which reduces the thermal damage of the flexible polymer substrate during the metallization process. The laser direct writing technique is based on the efficient and fast conversion of photon energy to thermal energy by direct excitation of the plasmon absorption of a metal nano-particle, which provides Cu microwiring with a low resistivity owing to the inhibition of the surface oxidation of the Cu nano-particle.

  18. Thin film metal coated fiber optic hydrophone probe.

    Science.gov (United States)

    Gopinath Minasamudram, Rupa; Arora, Piyush; Gandhi, Gaurav; Daryoush, Afshin S; El-Sherif, Mahmoud A; Lewin, Peter A

    2009-11-01

    Our purpose is to improve the performance sensitivity of a fiber sensor used as a fiber optic hydrophone probe (FOHP) by the addition of nanoscale thin film gold coating. The fiber is designed to provide a uniform and spatial averaging free response up to 100 MHz by etching down to an active diameter of approximately 9 mum. The performance sensitivity of straight cleaved (i.e., full size core and cladding) uncoated, tapered uncoated, and tapered thin film gold-coated fiber sensors was compared in the frequency range from 1.5 to 20 MHz in the presence of acoustic amplitude pressure levels as high as 6 MPa. An unprecedented voltage sensitivity of -245 dB relative to 1 V/muPa (560 mV/MPa) was measured for a thin film gold-coated FOHP by optimizing the gold coating thickness.

  19. Oxidation-Based Continuous Laser Writing in Vertical Nano-Crystalline Graphite Thin Films

    Science.gov (United States)

    Loisel, Loïc; Florea, Ileana; Cojocaru, Costel-Sorin; Tay, Beng Kang; Lebental, Bérengère

    2016-05-01

    Nano and femtosecond laser writing are becoming very popular techniques for patterning carbon-based materials, as they are single-step processes enabling the drawing of complex shapes without photoresist. However, pulsed laser writing requires costly laser sources and is known to cause damages to the surrounding material. By comparison, continuous-wave lasers are cheap, stable and provide energy at a more moderate rate. Here, we show that a continuous-wave laser may be used to pattern vertical nano-crystalline graphite thin films with very few macroscale defects. Moreover, a spatially resolved study of the impact of the annealing to the crystalline structure and to the oxygen ingress in the film is provided: amorphization, matter removal and high oxygen content at the center of the beam; sp2 clustering and low oxygen content at its periphery. These data strongly suggest that amorphization and matter removal are controlled by carbon oxidation. The simultaneous occurrence of oxidation and amorphization results in a unique evolution of the Raman spectra as a function of annealing time, with a decrease of the I(D)/I(G) values but an upshift of the G peak frequency.

  20. Site-selective electroless metallization on porous organosilica films by multisurface modification of alkyl monolayer and vacuum plasma.

    Science.gov (United States)

    Chen, Giin-Shan; Chen, Sung-Te; Chen, Yenying W; Hsu, Yen-Che

    2013-01-15

    Taking plasma-enhanced chemical vapor deposited porous SiOCH (p-SiOCH) and octadecyltrichlorosilane (OTS) as model cases, this study elucidates the chemical reaction pathways for alkyl-based self-assembled monolayers (SAMs) on porous carbon-doped organosilica films under N(2)-H(2) vacuum plasma illumination. In contrast to previous findings that carboxylic groups are found in alkyl-based SAMs only by exposure to oxygen-based plasma, this study discovers that, upon exposure to reductive nitrogen-based vacuum plasma, surface carboxylic functional groups can be instantly formed on OTS-coated p-SiOCH films. Particular attention is given to developing a multisurface modification process, starting with the modification of p-SiOCH films by N(2)-H(2) plasma and continuing with SAM deposition and plasma patterning; this ultimately leads to site-selective seeding for the spatially controlled fabrication of Cu-wire metallization by electroless deposition. Plasma diagnosis and X-ray near-edge absorption and Fourier transform infrared spectroscopies show that, by adequately controlling the plasma parameters, the bulk of the p-SiOCH films are free from plasma damage (in terms of degradation in bonding structures and electrical properties); the formation of the seed-trapping carboxylic functional groups on the surface, the key factor for the validity of this new seeding process, is due to a water-mediated chemical oxygenation route.

  1. Dual focused coherent beams for three-dimensional optical trapping and continuous rotation of metallic nanostructures

    Science.gov (United States)

    Xu, Xiaohao; Cheng, Chang; Zhang, Yao; Lei, Hongxiang; Li, Baojun

    2016-07-01

    Metallic nanoparticles and nanowires are extremely important for nanoscience and nanotechnology. Techniques to optically trap and rotate metallic nanostructures can enable their potential applications. However, because of the destabilizing effects of optical radiation pressure, the optical trapping of large metallic particles in three dimensions is challenging. Additionally, the photothermal issues associated with optical rotation of metallic nanowires have far prevented their practical applications. Here, we utilize dual focused coherent beams to realize three-dimensional (3D) optical trapping of large silver particles. Continuous rotation of silver nanowires with frequencies measured in several hertz is also demonstrated based on interference-induced optical vortices with very low local light intensity. The experiments are interpreted by numerical simulations and calculations.

  2. Oxygen Vacancy Induced Room-Temperature Metal-Insulator Transition in Nickelate Films and Its Potential Application in Photovoltaics.

    Science.gov (United States)

    Wang, Le; Dash, Sibashisa; Chang, Lei; You, Lu; Feng, Yaqing; He, Xu; Jin, Kui-juan; Zhou, Yang; Ong, Hock Guan; Ren, Peng; Wang, Shiwei; Chen, Lang; Wang, Junling

    2016-04-20

    Oxygen vacancy is intrinsically coupled with magnetic, electronic, and transport properties of transition-metal oxide materials and directly determines their multifunctionality. Here, we demonstrate reversible control of oxygen content by postannealing at temperature lower than 300 °C and realize the reversible metal-insulator transition in epitaxial NdNiO₃ films. Importantly, over 6 orders of magnitude in the resistance modulation and a large change in optical bandgap are demonstrated at room temperature without destroying the parent framework and changing the p-type conductive mechanism. Further study revealed that oxygen vacancies stabilized the insulating phase at room temperature is universal for perovskite nickelate films. Acting as electron donors, oxygen vacancies not only stabilize the insulating phase at room temperature, but also induce a large magnetization of ∼50 emu/cm³ due to the formation of strongly correlated Ni²⁺ t(2g)⁶e(g)² states. The bandgap opening is an order of magnitude larger than that of the thermally driven metal-insulator transition and continuously tunable. Potential application of the newly found insulating phase in photovoltaics has been demonstrated in the nickelate-based heterojunctions. Our discovery opens up new possibilities for strongly correlated perovskite nickelates.

  3. High index of refraction films for dielectric mirrors prepared by metal-organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Brusasco, R.M.

    1989-01-01

    A wide variety of metal oxides with high index of refraction can be prepared by Metal-Organic Chemical Vapor Deposition. We present some recent optical and laser damage results on oxide films prepared by MOCVD which could be used in a multilayer structure for highly reflecting (HR) dielectric mirror applications. The method of preparation affects both optical properties and laser damage threshold. 10 refs., 8 figs., 4 tabs.

  4. Dymensional impurity effects in a crystal structure of thin metal films

    Directory of Open Access Journals (Sweden)

    I.Yu. Protsenko

    2009-01-01

    Full Text Available In the present work it is established that under metal films condensation under rough vacuum conditions the formation of anomalous modifications, which are always observed in bulk samples, occurs. Based on the theoretical and experimental analysis of our and other authors results we concluded that these phases become stable due to the action of dimensional impurity effect and they are penetration phases of remaining atmosphere gases into metal lattice.

  5. Copper Benzenetricarboxylate Metal-Organic Framework Nucleation Mechanisms on Metal Oxide Powders and Thin Films formed by Atomic Layer Deposition.

    Science.gov (United States)

    Lemaire, Paul C; Zhao, Junjie; Williams, Philip S; Walls, Howard J; Shepherd, Sarah D; Losego, Mark D; Peterson, Gregory W; Parsons, Gregory N

    2016-04-13

    Chemically functional microporous metal-organic framework (MOF) crystals are attractive for filtration and gas storage applications, and recent results show that they can be immobilized on high surface area substrates, such as fiber mats. However, fundamental knowledge is still lacking regarding initial key reaction steps in thin film MOF nucleation and growth. We find that thin inorganic nucleation layers formed by atomic layer deposition (ALD) can promote solvothermal growth of copper benzenetricarboxylate MOF (Cu-BTC) on various substrate surfaces. The nature of the ALD material affects the MOF nucleation time, crystal size and morphology, and the resulting MOF surface area per unit mass. To understand MOF nucleation mechanisms, we investigate detailed Cu-BTC MOF nucleation behavior on metal oxide powders and Al2O3, ZnO, and TiO2 layers formed by ALD on polypropylene substrates. Studying both combined and sequential MOF reactant exposure conditions, we find that during solvothermal synthesis ALD metal oxides can react with the MOF metal precursor to form double hydroxy salts that can further convert to Cu-BTC MOF. The acidic organic linker can also etch or react with the surface to form MOF from an oxide metal source, which can also function as a nucleation agent for Cu-BTC in the mixed solvothermal solution. We discuss the implications of these results for better controlled thin film MOF nucleation and growth.

  6. Continuous Polyol Synthesis of Metal and Metal Oxide Nanoparticles Using a Segmented Flow Tubular Reactor (SFTR

    Directory of Open Access Journals (Sweden)

    Andrea Testino

    2015-06-01

    Full Text Available Over the last years a new type of tubular plug flow reactor, the segmented flow tubular reactor (SFTR, has proven its versatility and robustness through the water-based synthesis of precipitates as varied as CaCO3, BaTiO3, Mn(1−xNixC2O4·2H2O, YBa oxalates, copper oxalate, ZnS, ZnO, iron oxides, and TiO2 produced with a high powder quality (phase composition, particle size, and shape and high reproducibility. The SFTR has been developed to overcome the classical problems of powder production scale-up from batch processes, which are mainly linked with mass and heat transfer. Recently, the SFTR concept has been further developed and applied for the synthesis of metals, metal oxides, and salts in form of nano- or micro-particles in organic solvents. This has been done by increasing the working temperature and modifying the particle carrying solvent. In this paper we summarize the experimental results for four materials prepared according to the polyol synthesis route combined with the SFTR. CeO2, Ni, Ag, and Ca3(PO42 nanoparticles (NPs can be obtained with a production rate of about 1–10 g per h. The production was carried out for several hours with constant product quality. These findings further corroborate the reliability and versatility of the SFTR for high throughput powder production.

  7. Continuous Polyol Synthesis of Metal and Metal Oxide Nanoparticles Using a Segmented Flow Tubular Reactor (SFTR).

    Science.gov (United States)

    Testino, Andrea; Pilger, Frank; Lucchini, Mattia Alberto; Quinsaat, Jose Enrico Q; Stähli, Christoph; Bowen, Paul

    2015-06-08

    Over the last years a new type of tubular plug flow reactor, the segmented flow tubular reactor (SFTR), has proven its versatility and robustness through the water-based synthesis of precipitates as varied as CaCO3, BaTiO3, Mn(1-x)NixC2O4·2H2O, YBa oxalates, copper oxalate, ZnS, ZnO, iron oxides, and TiO2 produced with a high powder quality (phase composition, particle size, and shape) and high reproducibility. The SFTR has been developed to overcome the classical problems of powder production scale-up from batch processes, which are mainly linked with mass and heat transfer. Recently, the SFTR concept has been further developed and applied for the synthesis of metals, metal oxides, and salts in form of nano- or micro-particles in organic solvents. This has been done by increasing the working temperature and modifying the particle carrying solvent. In this paper we summarize the experimental results for four materials prepared according to the polyol synthesis route combined with the SFTR. CeO2, Ni, Ag, and Ca3(PO4)2 nanoparticles (NPs) can be obtained with a production rate of about 1-10 g per h. The production was carried out for several hours with constant product quality. These findings further corroborate the reliability and versatility of the SFTR for high throughput powder production.

  8. Temperature Sensitive Optical Phenomena in Heavy Metal Halide Films.

    Science.gov (United States)

    1979-01-08

    Heavy - metal halides such as Pb!2 and HgI2 exhibit a strongly tempera- ture dependent absorption edge at visible frequencies. The shift in the absorption...AOb9 537 ROCKWELL INTERNATIONAL ANAHEIM CA ELECTRONICS RESEAR—— ETC FIG L u G TEMPERATURE SENSITIVE OPTICAL PHENOMENA IN HEAVY METAL HALIDE F—— ETC (U...PHENOMENA IN HEAVY METAL HALIDE F — ET C( U) ,JAN 79 J D MC*LLEN, D M HEINZ. F S STEARNS DAAK7O— 77—C—01 6 5 UNCLASSIFIED C79 1501 _ _ U SB

  9. Molecular dynamics simulation of Cu-Zr-Al metallic-glass films under indentation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yun-Che, E-mail: yunche@mail.ncku.edu.tw; Wu, Chun-Yi

    2014-06-30

    In this paper, the (Cu{sub 50}Zr{sub 50}){sub 100-x}Al{sub x} (X = 0, 2, 4, 5, 6, 8, 10, 12, atomic percent) metallic-glass thin films on the titanium crystalline substrate were constructed by using molecular dynamics (MD) to simulate sputter deposition. The deposition simulations adopted a tight-binding potential with consideration of argon working gas from the pair-wise Moliere potential. The as-deposited films were amorphous and used as initial structures for nano-indentation simulations with a right-angle conical indenter tip to obtain their mechanical properties. All simulations were carried out at temperature 300 K to compare with experimental data. The radial distribution function of the film is calculated and compared with synchrotron experimental data. From the nanoindentation simulations, the hardness and Young's modulus of the films were calculated, as well as the pileup index under two different depth-to-thickness ratios. Our MD simulation results are consistent with experimental data. Furthermore, atomic strains were calculated to reveal deformation localization. In addition, elastic constants of the film and associated degrees of elastic anisotropy were studied to correlate structural anisotropy and to reveal structural relaxation. It is found that the deposited and MD-equilibrated films have notable anisotropic elastic constants, and their relaxation can be observed at the MD time scales. - Highlights: • Cu-Zr-Al metallic-glass thin films are prepared by sputter deposition simulations. • Metallic-glass films are characterized by molecular dynamics simulations. • Atomic structures are compared with synchrotron experiment. • Strain and elastic constants are studied in relation to structural relaxation.

  10. Nobel metal alloyed thin-films with optical properties on demand

    Science.gov (United States)

    Gong, Chen; Leite, Marina S.

    Metallic materials with tunable optical responses can enable the unprecedented control of optoelectronic and nanophotonic devices with enhanced performance, such as thin-film solar cells, metamaterials and metasurfaces for tunable absorbers and optical filters, among others. Here we present the alloying of noble metals, Ag, Au and Cu, to develop a novel class of material with optical response not achieved by pure metals. We fabricate binary mixtures with controlled chemical composition by co-sputtering. Ellipsometry and surface plasmon polariton coupling angle measurements are in excellent agreement when determining the real part of the dielectric function (ɛ1). Surprisingly, in some cases, a mixture provides a material with higher surface plasmon polariton quality factor than the corresponding pure metals. Our approach paves the way to implement metallic nanostructures with tunable absorption/transmission, overcoming the current limitation of the dielectric function of noble metals.

  11. Reactive Bonding Film for Bonding Carbon Foam Through Metal Extrusion

    CERN Document Server

    Chertok, Maxwell; Irving, Michael; Neher, Christian; Tripathi, Mani; Wang, Ruby; Zheng, Gayle

    2016-01-01

    Future tracking detectors, such as those under development for the High Luminosity LHC, will require mechanical structures employing novel materials to reduce mass while providing excellent strength, thermal conductivity, and radiation tolerance. Adhesion methods for such materials are under study at present. This paper demonstrates the use of reactive bonding film as an adhesion method for bonding carbon foam.

  12. Bauschinger effect in thin metal films: Discrete dislocation dynamics study

    NARCIS (Netherlands)

    Davoudi, K.M.; Nicola, L.; Vlassak, J.J.

    2014-01-01

    The effects of dislocation climb on plastic deformation during loading and unloading are studied using a two-dimensional discrete dislocation dynamics model. Simulations are performed for polycrystalline thin films passivated on both surfaces. Dislocation climb lowers the overall level of the stress

  13. Hydrogen-doping stabilized metallic VO{sub 2} (R) thin films and their application to suppress Fabry-Perot resonances in the terahertz regime

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yong; Pan, Xuan; Bernussi, Ayrton A.; Fan, Zhaoyang, E-mail: Zhaoyang.Fan@ttu.edu [Department of Electrical and Computer Engineering and Nano Tech Center, Lubbock, Texas 79409 (United States); Karaoglan-Bebek, Gulten [Department of Physics and Nano Tech Center, Lubbock, Texas 79409 (United States); Holtz, Mark [Department of Physics and MSEC, Texas State University, San Marcos, Texas 78666 (United States)

    2014-06-16

    We demonstrate that catalyst-assisted hydrogen spillover doping of VO{sub 2} thin films significantly alters the metal-insulator transition characteristics and stabilizes the metallic rutile phase at room temperature. With hydrogen inserted into the VO{sub 2} lattice, high resolution X-ray diffraction reveals expansion of the V-V chain separation when compared to the VO{sub 2}(R) phase. The donated free electrons, possibly from O-H bond formation, stabilize the VO{sub 2}(R) to low temperatures. By controlling the amount of dopants to obtain mixed insulating and metallic phases, VO{sub 2} resistivity can be continuously tuned until a critical condition is achieved that suppresses Fabry-Perot resonances. Our results demonstrate that hydrogen spillover is an effective technique to tune the electrical and optical properties of VO{sub 2} thin films.

  14. Handshake electron transfer from hydrogen Rydberg atoms incident at a series of metallic thin films.

    Science.gov (United States)

    Gibbard, J A; Softley, T P

    2016-06-21

    Thin metallic films have a 1D quantum well along the surface normal direction, which yields particle-in-a-box style electronic quantum states. However the quantum well is not infinitely deep and the wavefunctions of these states penetrate outside the surface where the electron is bound by its own image-charge attraction. Therefore a series of discrete, vacant states reach out from the thin film into the vacuum increasing the probability of electron transfer from an external atom or molecule to the thin film, especially for the resonant case where the quantum well energy matches that of the atom. We show that "handshake" electron transfer from a highly excited Rydberg atom to these thin-film states is experimentally measurable. Thicker films have a wider 1D box, changing the energetic distribution and image-state contribution to the thin film wavefunctions, resulting in more resonances. Calculations successfully predict the number of resonances and the nature of the thin-film wavefunctions for a given film thickness.

  15. Ligand field effect at oxide-metal interface on the chemical reactivity of ultrathin oxide film surface.

    Science.gov (United States)

    Jung, Jaehoon; Shin, Hyung-Joon; Kim, Yousoo; Kawai, Maki

    2012-06-27

    Ultrathin oxide film is currently one of the paramount candidates for a heterogeneous catalyst because it provides an additional dimension, i.e., film thickness, to control chemical reactivity. Here, we demonstrate that the chemical reactivity of ultrathin MgO film grown on Ag(100) substrate for the dissociation of individual water molecules can be systematically controlled by interface dopants over the film thickness. Density functional theory calculations revealed that adhesion at the oxide-metal interface can be addressed by the ligand field effect and is linearly correlated with the chemical reactivity of the oxide film. In addition, our results indicate that the concentration of dopant at the interface can be controlled by tuning the drawing effect of oxide film. Our study provides not only profound insight into chemical reactivity control of ultrathin oxide film supported by a metal substrate but also an impetus for investigating ultrathin oxide films for a wider range of applications.

  16. YBa2Cu3O7 films grown by metal cosputtering

    Science.gov (United States)

    Steinberg, Richard N.; McCambridge, James D.; Prober, Daniel E.; Guenin, Bruce M.

    1992-04-01

    Superconducting YBa2Cu3O7 films have been grown in situ by simultaneously sputtering from Y, BaCu, and Cu targets. One advantage of such metal cosputtering is the higher deposition rate compared to oxide target sputtering. Another advantage is the ability to control the individual element rates to vary composition or to substitute for any of the metals without interrupting film growth and without making additional composite targets. To prevent film damage due to oxygen ion bombardment during film growth which was observed when the sputter guns faced the substrate (on-axis sputtering), an off-axis geometry was used. One disadvantage we found with in situ metal cosputtering was that reproducibility of stoichiometries was difficult because of the presence of oxygen at the targets. To minimize the oxygen partial pressure at the targets during sputtering, the chamber was differentially pumped. Films grown in the off-axis geometry with a substrate temperature near 700 °C, a chamber pressure of 7.5 mT, and an O2:Ar flow ratio of 1:50 had zero resistance at 85 K. Results for on-axis, composite target magnetron sputtering with a high-strength magnet are also presented. These results are not promising.

  17. Composite thin film materials on the basis of silver nanostructures on polymer matrix by methods of chemical metallization and self-assembling

    Science.gov (United States)

    Skoptsov, Evgeniy; Agabekov, Vladimir; Binhussain, Mohammed A.; Egorov, Dmitriy; Ropot, Piotr

    2014-08-01

    The techniques of formation of thin metallic coatings by deposition of silver nanoparticles (NPs) from solution onto the surface of glass and silicon substrates modified by polyelectrolytes were developed. The possibilities of the adsorption of individual silver particles, as well as creation of continuous films on their basis, were shown. The transmission, absorption and reflection spectra of obtained coatings were investigated. The most promising structure for metamaterials creation from the list of formed one was determined—solid thin film of Ag NPs on a glass substrate modified by polyethylenimine.

  18. Improving light harvesting in polymer photodetector devices through nanoindented metal mask films

    NARCIS (Netherlands)

    Macedo, A. G.; Zanetti, F.; Mikowski, A.; Hummelen, J. C.; Lepienski, C. M.; da Luz, M. G. E.; Roman, L. S.

    2008-01-01

    To enhance light harvesting in organic photovoltaic devices, we propose the incorporation of a metal (aluminum) mask film in the system's usual layout. We fabricate devices in a sandwich geometry, where the mask (nanoindented with a periodic array of holes of sizes d and spacing s) is added between

  19. Impermeable flexible liquid barrier film for encapsulation of DSSC metal electrodes

    Science.gov (United States)

    Yang, Junghee; Min, Misook; Yoon, Yeoheung; Kim, Won Jung; Kim, Sol; Lee, Hyoyoung

    2016-06-01

    Encapsulation of electronic devices such as dye-sensitized solar cells (DSSCs) is prone to degradation under normal atmospheric conditions, even with hermetic barriers on the metal electrodes. Overcoming this problem is crucial to increasing DSSC lifetimes and making them commercially viable. Herein, we report a new impermeable flexible liquid barrier film using polyvinyl alcohol (PVA) and partially reduced graphene oxide (PrGO), which dramatically enhances the lifetime of Ag metal electrodes (typically used in DSSCs) immersed in a highly acidic iodolyte solution. The Ag metal electrode encapsulated by the PVA/PrGO film survived for over 500 hrs, superior to existing barriers of glass frits, epoxy resins and polymers. The PVA/PrGO film strongly adheres to the Ag metal surface, and the resulting PVA/PrGO/Ag electrode is stable even on a curved substrate, with a sheet resistance nearly independent of curvature. These results give new insight for the design of high-performance and solution-processable flexible liquid barrier films for a wide range of applications, in particular for the encapsulation of electronic devices with liquid electrolytes.

  20. Characterization of diamond film and bare metal photocathodes as a function of temperature and surface preparation

    Energy Technology Data Exchange (ETDEWEB)

    Shurter, R.P.; Moir, D.C.; Devlin, D.J.

    1996-07-01

    High current photocathodes using bare metal and polycrystalline diamond films illuminated by ultraviolet lasers are being developed at Los Alamos for use in a new generation of linear induction accelerators. These photocathodes must be able to produce multiple 60 ns pulses separated by several to tens of nanoseconds. The vacuum environment in which the photocathodes must operate is 10{sup -5} torr.

  1. Impermeable flexible liquid barrier film for encapsulation of DSSC metal electrodes.

    Science.gov (United States)

    Yang, Junghee; Min, Misook; Yoon, Yeoheung; Kim, Won Jung; Kim, Sol; Lee, Hyoyoung

    2016-06-06

    Encapsulation of electronic devices such as dye-sensitized solar cells (DSSCs) is prone to degradation under normal atmospheric conditions, even with hermetic barriers on the metal electrodes. Overcoming this problem is crucial to increasing DSSC lifetimes and making them commercially viable. Herein, we report a new impermeable flexible liquid barrier film using polyvinyl alcohol (PVA) and partially reduced graphene oxide (PrGO), which dramatically enhances the lifetime of Ag metal electrodes (typically used in DSSCs) immersed in a highly acidic iodolyte solution. The Ag metal electrode encapsulated by the PVA/PrGO film survived for over 500 hrs, superior to existing barriers of glass frits, epoxy resins and polymers. The PVA/PrGO film strongly adheres to the Ag metal surface, and the resulting PVA/PrGO/Ag electrode is stable even on a curved substrate, with a sheet resistance nearly independent of curvature. These results give new insight for the design of high-performance and solution-processable flexible liquid barrier films for a wide range of applications, in particular for the encapsulation of electronic devices with liquid electrolytes.

  2. Metal-insulator phase transition in a VO2 thin film observed with terahertz spectroscopy

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd; Fischer, Bernd M.; Thoman, Andreas

    2006-01-01

    We investigate the dielectric properties of a thin VO2 film in the terahertz frequency range in the vicinity of the semiconductor-metal phase transition. Phase-sensitive broadband spectroscopy in the frequency region below the phonon bands of VO2 gives insight into the conductive properties...

  3. Tuning the work function of ultrathin oxide films on metals by adsorption of alkali atoms.

    Science.gov (United States)

    Martinez, Umberto; Giordano, Livia; Pacchioni, Gianfranco

    2008-04-28

    We report a theoretical investigation of the adsorption of alkali metal atoms deposited on ultrathin oxide films. The properties of Li, Na, and K atoms adsorbed on SiO(2)/Mo(112) and of K on MgO / Ag(100) and TiO(2)/Pt(111) have been analyzed with particular attention to the induced changes in the work function of the system, Phi. On the nonreducible SiO(2) and MgO oxide films there is a net transfer of the outer ns electron of the alkali atom to the metal substrate conduction band; the resulting surface dipole substantially lowers Phi. The change in Phi depends (a) on the adsorption site (above the oxide film or at the interface) and (b) on the alkali metal coverage. Deposition of K on reducible TiO(2) oxide films results in adsorbed K(+) ions and in the formation of Ti(3+) ions. No charge transfer to the metal substrate is observed but also in this case the surface dipole resulting from the K-TiO(2) charge transfer has the effect to considerably reduce the work function of the system.

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

    Science.gov (United States)

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

    2016-08-01

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

  5. Homojunction solution-processed metal oxide thin-film transistors using passivation-induced channel definition.

    Science.gov (United States)

    Kim, Jung Hyun; Rim, You Seung; Kim, Hyun Jae

    2014-04-09

    A simple method of channel passivation and physical definition of solution-processed metal oxide thin-film transistors (TFTs) has been developed for aluminum oxide (AlOx) and indium oxide (InOx) thin films. A photoresist-free-based ultraviolet (UV) patterning process was used to define an InOx layer as the source/drain region and an AlOx layer as a passivation layer on the InOx layer. The Al diffused into the patterned InOx thin film during a thermal annealing step. As an electrode, the patterned InOx thin film had low resistivity, and as a channel, the Al-diffused InOx thin film had a low carrier concentration. Furthermore, the diffused Al behaved as a carrier suppressor by reducing oxygen vacancies within the InOx thin film. We succeeded in forming a coplanar homojunction-structured metal oxide TFT that used the passivation-induced channel-defining (PCD) method with an AlOx/InOx bilayer. The PCD TFT had a field-effect mobility of 0.02 cm(2)/V·s, a threshold voltage of -1.88 V, a subthreshold swing of 0.73 V/decade, and an on/off current ratio of 2.75 × 10(6) with a width/length (W/L) of 2000 μm/400 μm.

  6. Intercalation of two-dimensional graphite films on metals by atoms and molecules

    CERN Document Server

    Gall, N R; Tontegode, A Ya; Usufov, M M

    1999-01-01

    An analysis is made of some general laws governing a new physical effect, i.e., the spontaneous penetration of particles (atoms, C/sub 60/ molecules) adsorbed on a two-dimensional graphite film on a metal (Ir, Re, Pt, Mo, ...) to beneath the graphite film (intercalation). It is shown that atoms having low ionization potentials (Cs, K, Na) intercalate a two-dimensional graphite film on iridium at T=300-400 K with an efficiency Aleph approximately=0.5, accumulating beneath the film to a concentration of up to a monolayer. Atoms having high ionization potentials (Si, Pt, Ni, C, Mo, etc.) intercalate a two- dimensional graphite film on iridium at T approximately=1000 K with an efficiency Aleph approximately=1, forming beneath the film a thick intercalate layer which is strongly bonded chemically to the metal substrate but is probably weakly bonded to the graphite monolayer by van der Waals forces. The presence of a graphite "lid" impeding the escape of atoms from the intercalated state up to record high temperatu...

  7. Elaboration of strontium ruthenium oxide thin films on metal substrates by chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Seveno, R. [Universite de Nantes, Institut de Recherche en Electrotechnique et Electronique de Nantes Atlantique (IREENA), 2, rue de la Houssiniere, BP 92208, 44322 Nantes Cedex 3 (France)]. E-mail: raynald.seveno@univ-nantes.fr; Braud, A. [Universite de Nantes, Institut de Recherche en Electrotechnique et Electronique de Nantes Atlantique (IREENA), 2, rue de la Houssiniere, BP 92208, 44322 Nantes Cedex 3 (France); Gundel, H.W. [Universite de Nantes, Institut de Recherche en Electrotechnique et Electronique de Nantes Atlantique (IREENA), 2, rue de la Houssiniere, BP 92208, 44322 Nantes Cedex 3 (France)

    2005-12-22

    In order to improve the structural interface between a metal substrate and a lead zirconate titanate (Pb(ZrTi)O{sub 3}, PZT) ferroelectric thin film, the elaboration of strontium ruthenium oxide (SrRuO{sub 3}) by chemical solution deposition is studied. The SrRuO{sub 3} thin films were realized by multiple spin-coating technique and the temperature of the rapid thermal annealing process was optimized. The crystallization behavior was examined by X-ray diffraction; surface analyses using scanning electron microscope and atomic force microscope techniques showed the influence of the SrRuO{sub 3} layer at the interface PZT/metal on the morphology of the ferroelectric thin film. From the electrical measurements, a coercive electric field around 25 kV/cm and a remanent polarization of approximately 30 {mu}C/cm were found.

  8. Effects of annealing on mechanical behavior of Zr–Ti–Ni thin film metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chu-Shuan [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Yiu, Pakman [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong (China); Li, Chia-Lin; Chu, Jinn P. [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Shek, Chan-Hung [Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong (China); Hsueh, Chun-Hway, E-mail: hsuehc@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-07-01

    Zr{sub 46}Ti{sub 26}Ni{sub 28} thin film metallic glass was fabricated by radio frequency magnetron single target sputtering on Si and stainless steel substrates. The as-deposited film was found to be fully amorphous with high glass transition and crystallization temperatures of 466 °C and 502 °C, respectively. Its hardness progressively increased from 6.2 GPa to as high as 11.1 GPa when subjected to annealing near the glass-transition temperature at 450 °C. It was also of good adhesive strength and scratch resistance after the annealing treatment at 400 °C. Transmission electron microscopy results revealed annealing-induced nanocrystals that accounted for such superior mechanical properties. With the above unique properties, Zr–Ti–Ni thin film metallic glass has the potential for the fabrication of high strength micro parts and protective coating.

  9. On calculating the energy characteristics of a metal film with a dielectric coating

    Science.gov (United States)

    Babich, A. V.

    2014-02-01

    A method for calculating the characteristics of a metal film in a dielectric surroundings is suggested. The most interesting case of asymmetric metal-dielectric sandwiches, in which the dielectrics on both sides of the film are different, is considered in the context of the Kohn-Sham modified method. The spectrum, the electron work function, and the surface energy of polycrystalline and single-crystal films placed into passive insulators are calculated for the first time. In general, the dielectric surroundings leads to a negative change in the electron work function and the surface energy. In addition to size-effect-related changes, the shift of the work function is determined by the arithmetic mean of the dielectric constants of the surrounding media. Calculations have been performed for Na, Al, and Pb.

  10. Quantum-classical transition in the electron dynamics of thin metal films

    Energy Technology Data Exchange (ETDEWEB)

    Jasiak, R; Manfredi, G; Hervieux, P-A [Institut de Physique et Chimie des Materiaux, CNRS and Universite de Strasbourg, BP 43, F-67034 Strasbourg (France); Haefele, M [INRIA Nancy Grand-Est and Institut de Recherche en Mathematiques Avancees, 7 rue Rene Descartes, F-67084 Strasbourg (France)], E-mail: Giovanni.Manfredi@ipcms.u-strasbg.fr

    2009-06-15

    The quantum electrons dynamics in a thin metal film is studied numerically using the self-consistent Wigner-Poisson equations. The initial equilibrium is computed from the Kohn-Sham equations at finite temperature, and then mapped into the phase-space Wigner function. The time-dependent results are compared systematically with those obtained previously with a classical approach (Vlasov-Poisson equations). It is found that, for large excitations, the quantum and classical dynamics display the same low-frequency oscillations due to ballistic electrons bouncing back and forth on the film surfaces. However, below a certain excitation energy (roughly corresponding to one quantum of plasmon energy {Dirac_h}{omega}{sub p}), the quantum and classical results diverge, and the ballistic oscillations are no longer observed. These results provide an example of a quantum-classical transition that may be observed with current pump-probe experiments on thin metal films.

  11. Coating thickness control in continuously fabricating metallic glass-coated composite wires

    Science.gov (United States)

    Zhang, Bao-yu; Chen, Xiao-hua; Lu, Zhao-ping; Hui, Xi-dong

    2013-05-01

    A continuous production process was developed for coating bulk metallic glasses on the metallic wire surface. The effects of processing parameters, including the drawing velocity and coating temperature, on the coating thickness were investigated. It is found that the coating thickness increases with the increase in drawing velocity but decreases with the increase in coating temperature. A fluid mechanical model was developed to quantify the coating thickness under various processing conditions. By using this theoretical model, the coating thickness was calculated, and the calculated values are in good agreement with the experimental data.

  12. Impact of the epilayer doping on the performance of thin metal film Ni2Si/4H-SiC Schottky photodiodes

    Science.gov (United States)

    Mazzillo, M.; Sciuto, A.; Marchese, S.

    2014-12-01

    In the last few years silicon carbide (SiC) has emerged as a suitable material for the fabrication of ultraviolet light detectors due to lower leakage current, intrinsic visible blindness and mature process technology. In this paper we report on the electro-optical characteristics of continuous thin metal film Ni2Si/4H-SiC photodiodes with very low surface epilayer doping properly designed for ultraviolet (UV) sunlight monitoring.

  13. Achieving Uniform Monolayer Transition Metal Dichalcogenides Film on Silicon Wafer via Silanization Treatment: A Typical Study on WS2.

    Science.gov (United States)

    Chen, Ying; Gan, Lin; Li, Huiqiao; Ma, Ying; Zhai, Tianyou

    2017-02-01

    A silanization reaction is employed to improve the dispersion of precursors on a silicon wafer for a large-size uniform transition metal dichalcogenide (TMD) film synthesis and to achieve a highly crystalline monolayer WS2 film up to 1 cm(2) . The novel strategy is also verified for the synthesis of WSe2 and MoS2 uniform films, suggesting universality for TMD film fabrication.

  14. Passive film formation on metals in thionyl-chloride electrolytes for lithium batteries

    Science.gov (United States)

    Cieslak, W. R.; Delnick, F. M.; Peebles, D. E.; Rogers, J. W., Jr.

    We have studied the anodic behavior of Pt, Mo, Ni, and stainless steel (SS) electrodes in 1.5M LiAlCl/SOCl solution in order to determine the mechanisms by which these metals resist corrosion. Polarization and complex impedance indicate that Pt and Mo behave as inert electrodes, while Ni and SS form passive films in this electrolyte. X-ray Photoelectron Spectroscopy (XPS) confirms the lack of oxidized metal species on the Pt and Mo surfaces following anodic polarization. XPS results also show that the Ni and SS do form passive layers, and identifies these layers as predominantly metal chlorides.

  15. Superresolution observed from evanescent waves transmitted through nano-corrugated metallic films

    CERN Document Server

    Ben-Aryeh, Y

    2015-01-01

    Plane EM waves transmitted through nano-corrugated metallic thin films produce evanescent waves which include the information on the nano-structures. The production of the evanescent waves at the metallic surface are analyzed. A microsphere located above the metallic surface collects the evanescent waves which are converted into propagating waves. The equations for the refraction at the boundary of the microsphere and the use of Snell's law for evanescent waves are developed. The magnification of the nano-structure images is explained by a geometric optics description, but the high resolution is related to the evanescent waves properties.

  16. Quantum Transport and Surface Scattering in Magnetic Metallic Film

    Institute of Scientific and Technical Information of China (English)

    HU Yin; DONG Zheng-Chao

    2008-01-01

    Taking into account the quantum size effect and the spin dependence of the electronic band structure,and including the spin dependence of the scattering from bulk impurities and two different sets of surface roughness,we present a theory on the electronic transport in magnetic film,in which the average autocorrelation function (ACF) for surface roughness is described by a Gaussion model.Our result shows that the conductivity is a sensitive function of surface roughness and exchange energy.It is also found that in the thin film limit and in the lower-order approximation of the surface scattering,the total conductivity is given by a sum of conductivities of all the subbands and the two spin channels,for each subband and each spin channel the scattering rates due to the impurities and two surfaces are additive.

  17. Ferromagnetism and interlayer exchange coupling in thin metallic films

    Energy Technology Data Exchange (ETDEWEB)

    Kienert, Jochen

    2008-07-15

    This thesis is concerned with the ferromagnetic Kondo lattice (s-d,s-f) model for film geometry. The spin-fermion interaction of this model refers to substances in which localized spins interact with mobile charge carriers like in (dilute) magnetic semiconductors, manganites, or rare-earth compounds. The carrier-mediated, indirect interaction between the localized spins comprises the long-range, oscillatory RKKY exchange interaction in the weak-coupling case and the short-range doubleexchange interaction for strong spin-fermion coupling. Both limits are recovered in this work by mapping the problem onto an effective Heisenberg model. The influence of reduced translational symmetry on the effective exchange interaction and on the magnetic properties of the ferromagnetic Kondo lattice model is investigated. Curie temperatures are obtained for different parameter constellations. The consequences of charge transfer and of lattice relaxation on the magnetic stability at the surface are considered. Since the effective exchange integrals are closely related to the electronic structure in terms of the density of states and of the kinetic energy, the discussion is based on the modifications of these quantities in the dimensionally-reduced case. The important role of spin waves for thin film and surface magnetism is demonstrated. Interlayer exchange coupling represents a particularly interesting and important manifestation of the indirect interaction among localized magnetic moments. The coupling between monatomic layers in thin films is studied in the framework of an RKKY approach. It is decisively determined by the type of in-plane and perpendicular dispersion of the charge carriers and is strongly suppressed above a critical value of the Fermi energy. Finally, the temperature-dependent magnetic stability of thin interlayer-coupled films is addressed and the conditions for a temperature-driven magnetic reorientation transition are discussed. (orig.)

  18. Ultra-Thin Metal Films for Enhanced Solar Absorption

    CERN Document Server

    Ahmad, N; Teng, M; Cryan, M J

    2012-01-01

    This paper presents modelled results for optical absorption in ultra-thin films of nickel, gold and silver over the solar spectrum. It is found in the case of nickel there is an optimum thickness for maximum solar absorption around 10-13nm. This effect is not observed for gold or silver. It is postulated that this is an interference effect occurring due the particular real and imaginary refractive profile of nickel across the solar spectrum.

  19. Surface Chemistry of Nano-Structured Mixed Metal Oxide Films

    Science.gov (United States)

    2012-12-11

    Low Temperature Synthesis and Characterization of Nanocrystalline Titanium Carbide with Tunable Porous Architectures, Chemistry of Materials, (01...of the C–H bond to form carboxyl, both of which decompose via a COd 2 intermediate to evolve CO2 and H2. High surface area, porous titanium carbide films...characterization of nanocrystalline titanium carbide with tunable porous architectures” Chem. Mater. 22, 319-329 (2010). http://dx.doi.org/10.1021/cm902184m 3

  20. Preparation and Properties of Cereal-Metal Complex Films

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results Various kinds of biodegradable polymer materials have been researched[1]. In our previous papers,cereals such as wheat,buckwheat,glutinous rice and nonglutinous rice were polycondenced with citric acid and polysilicic acid to prepare copolymer films respectively[2,3].These copolymer fims have relatively good mechanical properties but the water proofness is not so good.Recently,some cereals such as wheat,glutinous rice,nonglutinous rice,kaoliang,millet and maize were reacted with copper chlorid...

  1. Implacable images: why epileptiform events continue to be featured in film and television.

    Science.gov (United States)

    Kerson, Toba Schwaber; Kerson, Lawrence A

    2006-06-01

    Epileptiform events have been portrayed in film since 1900 and on television since the 1950's. Over time, portrayals have not reflected medicine's understanding of epilepsy. At present, it is unlikely that individuals who do not have a close relationship with someone with a seizure-disorder will witness a seizure. Because fictive and often incorrect images appear increasingly, many think of them as accurate depictions. The research addresses three questions in relation to these images: How do directors use the images? Why do uses of seizures in visual media not reflect contemporary scientific knowledge? Why have they persisted and increased in use? Data consist of material from 192 films and television episodes. The general category of seizures includes seizures in characters said to have epilepsy or some other condition, seizures related to drug or alcohol use, pseudoseizures and feigned seizures, and, a category in which, for example, someone is described as "having a fit." The research demonstrates how epileptiform events drive the narrative, support the genre, evoke specific emotional reactions, accentuate traits of characters with seizures, highlight qualities of other characters through their responses to the seizures, act as catalysts for actions, and enhance the voyeuristic experience of the audience. Twenty video sequences are included in the manuscript. The authors conclude that the visual experience of seizures remains so enthralling that its use is most likely to increase particularly on television, and that as the public has less experience with real seizures, depictions in film will continue to be more concerned with what the image can do for the show and less interested in accurate portrayals. Ways to influence depictions are suggested.

  2. Metal-Organic Coordination Network Thin Film by Surface-Induced Assembly.

    Science.gov (United States)

    Laokroekkiat, Salinthip; Hara, Mitsuo; Nagano, Shusaku; Nagao, Yuki

    2016-07-01

    The growth of metal-organic coordination network thin films on surfaces has been pursued extensively and intensively to manipulate the molecular arrangement. For this study, the oriented multilayer thin films based on porphyrinic nanoarchitecture were synthesized toward metal-organic coordination networks using surface-induced assembly (SIA). Nanoscale molecular thin films were prepared at room temperature using cobalt(II) ion and porphyrin building blocks as precursors. Stepwise growth with a highly uniform layer was characterized using UV-vis, AFM, IR, and XPS studies. The grazing incidence small-angle X-ray scattering and X-ray reflectivity results remarkably suggested a periodic structure in in-plane direction with constant and high mass density (ca. 1.5 g/cm(3)) throughout the multilayer formation. We propose that orientation of the porphyrin macrocycle plane with a hexagonal packed model by single anchoring mode was tilted approximately 60° with respect to the surface substrate. It is noteworthy that the well-organized structure of porphyrin-based macrocyclic framework on the amine-terminated surface substrate can be achieved efficiently using a simple SIA approach under mild synthetic conditions. The synthesized thin film provides a different structure from that obtained using bulk synthesis. This result suggests that the SIA technique can control not only the film thickness but also the structural arrangement on the surface. This report of our research provides insight into the ordered porphyrin-based metal-organic coordination network thin films, which opens up opportunities for exploration of unique thin film materials for diverse applications.

  3. Patterned thin metal film for the lateral resolution measurement of photoacoustic tomography

    Directory of Open Access Journals (Sweden)

    Kim Do-Hyun

    2012-07-01

    Full Text Available Abstract Background Image quality assessment method of photoacoustic tomography has not been completely standardized yet. Due to the combined nature of photonic signal generation and ultrasonic signal transmission in biological tissue, neither optical nor ultrasonic traditional methods can be used without modification. An optical resolution measurement technique was investigated for its feasibility for resolution measurement of photoacoustic tomography. Methods A patterned thin metal film deposited on silica glass provides high contrast in optical imaging due to high reflectivity from the metal film and high transmission from the glass. It provides high contrast when it is used for photoacoustic tomography because thin metal film can absorb pulsed laser energy. An US Air Force 1951 resolution target was used to generate patterned photoacoustic signal to measure the lateral resolution. Transducer with 2.25 MHz bandwidth and a sample submerged in water and gelatinous block were tested for lateral resolution measurement. Results Photoacoustic signal generated from a thin metal film deposited on a glass can propagate along the surface or through the surrounding medium. First, a series of experiments with tilted sample confirmed that the measured photoacoustic signal is what is propagating through the medium. Lateral resolution of the photoacoustic tomography system was successfully measured for water and gelatinous block as media: 0.33 mm and 0.35 mm in water and gelatinous material, respectively, when 2.25 MHz transducer was used. Chicken embryo was tested for biomedical applications. Conclusions A patterned thin metal film sample was tested for its feasibility of measuring lateral resolution of a photoacoustic tomography system. Lateral resolutions in water and gelatinous material were successfully measured using the proposed method. Measured resolutions agreed well with theoretical values.

  4. Simulations of enhanced absorption in composite embedded, insulated metal nanopatterns for ultrathin film photovoltaics

    Science.gov (United States)

    Liu, Xinyu; Ye, Fan; Burns, Michael J.; Naughton, Michael J.

    2012-02-01

    In recent work [1], a concept of employing embedded metallic nanopatterns (EMN) in ultrathin film solar cells was discussed. Elsewhere in this conference, Fan et al. advance this with a scheme for embedded insulated metallic nanopatterns (EIMN) that is designed to avoid deleterious carrier recombination as would result from bare metal inclusions in a PV film. However, a practical route to fabricating EIMNs of desired shapes for eventual scale production is nontrivial. Here, we introduce two notions toward that goal, nano-stamping and spin-coating, of compact arrays of metallic core/insulating shell nanoparticles (MNP). We show by simulations that optical absorption of an EIMN composed of arrays of core-shell MNPs having SiO2 coatings is essentially the same as that of an EMN composed of solid metals without insulation, with absorption concentrated in the surrounding PV medium. These concepts may provide practical routes for scalability of EIMN-based ultrathin film plasmonic solar cells.[4pt] [1] F. Ye, M. J. Burns, M. J. Naughton, Proc. SPIE 8111, 811103 (2011), and this conference.

  5. Dynamics of metal-induced crystallization of ultrathin Ge films by rapid thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Yuanxun; Huang, Shujuan; Shrestha, Santosh; Conibeer, Gavin [School of Photovoltaic and Renewable Energy Engineering, UNSW Australia, Sydney 2052 (Australia)

    2015-12-07

    Though Ge crystallization has been widely studied, few works investigate metal-induced crystallization of ultrathin Ge films. For 2 nm Ge films in oxide matrix, crystallization becomes challenging due to easy oxidation and low mobility of Ge atoms. Introducing metal atoms may alleviate these problems, but the functions and the behaviours of metal atoms need to be clarified. This paper investigates the crystallization dynamics of a multilayer structure 1.9 nm Ge/0.5 nm Al/1.5 nm Al{sub 2}O{sub 3} under rapid thermal annealing (RTA). The functions of metal atoms, like effective anti-oxidation, downshifting Raman peaks, and incapability to decrease crystallization temperature, are found and explained. The metal behaviours, such as inter-diffusion and defect generation, are supported with direct evidences, Al-Ge nanobicrystals, and Al cluster in Ge atoms. With these understandings, a two-step RTA process achieves high-quality 2 nm nanocrystal Ge films with Raman peak at 298 cm{sup −1} of FWHM 10.3 cm{sup −1} and atomic smooth interfaces.

  6. Growth, morphology, and conductivity in semimetallic/metallic films on Si(001)

    Energy Technology Data Exchange (ETDEWEB)

    Jnawali, Giriraj

    2009-06-09

    This dissertation deals with the study of epitaxial growth of semimetallic (Bi) and metallic (Ag) films on Si(001) as well as in situ electrical transport study of those films via surface manipulation. The focus of the transport measurements is to study the influence of the surface morphology or structure on the resistance of the film. In spite of the large lattice mismatch and different lattice geometry, it is possible to grow epitaxial Bi(111) films on Si(001) substrates, which are surprisingly smooth, relaxed and almost free of defects. Due to the two-fold symmetry of the substrates, the Bi(111) film is composed of crystallites rotated by 90 with respect to each other. Annealing of 6 nm film from 150 K to 450 K enables the formation of a periodic interfacial misfit dislocations, which accommodates a remaining lattice mismatch of 2.3 %. The surface/interface roughness and the bulk defect density of the film found to be extremely low, indicating the high crystalline quality of the film with atomically smooth surface and abrupt interface. Similar to the Bi films, Ag grows in a (111) orientation on Si(001) with two 90 rotated domains. The remaining strain of 2.2 % (tensile) is accommodated by the formation of an ordered network of dislocations. The Ag film exhibits atomically smooth surface. Those Bi films and Ag films were used as model systems to study the influence of the surface morphology on the electrical resistance. Surprisingly, all the Bi films (3-170 nm thicknesses) have shown an anomalous behavior of conductance with temperature and thickness. As in the case of doped semiconductor, the conductance increases exponentially from 150 K to 300 K and saturates at 350 K before finally decreasing with temperature. In situ measurements of the resistance during additional Bi deposition on the smooth Bi(111) films exhibit a square root dependent with coverage after a linear increase at very low coverage (1 % of a BL). During additional deposition of Bi, carriers are

  7. Self-organized micro-holes on titania based sol-gel films under continuous direct writing with a continuous wave ultraviolet laser

    Energy Technology Data Exchange (ETDEWEB)

    Bakhti, S.; Destouches, N.; Gamet, E.; Reynaud, S. [University of Lyon, F. 42023 Saint-Etienne (France); CNRS, UMR 5516, Laboratoire Hubert Curien, 18 Rue Pr. Lauras F-42000 Saint-Etienne (France); University of Saint-Etienne, Jean Monnet, F-42000 Saint-Etienne (France); Balan, L. [Institut de Sciences des Materiaux de Mulhouse, CNRS UMR 7361, Universite de Haute Alsace, 15 rue Jean Starcky, 68057 Mulhouse (France)

    2013-05-27

    The microstructuring of titania based sol-gel films is investigated by direct writing with a continuous wave ultraviolet laser beam emitting at 244 nm. Depending on the exposure conditions, the films exhibit a volume expansion, a volume shrinkage, a self-shaped delamination, or are damaged. This paper is mainly focused on the regime where spontaneous local delamination occurs, which corresponds to a narrow range of laser irradiances and writing speeds. In this regime, self-organized round-shape micro-holes opened on the substrate are generated.

  8. Spin dependent transport of hot electrons through ultrathin epitaxial metallic films

    Energy Technology Data Exchange (ETDEWEB)

    Heindl, Emanuel

    2010-06-23

    In this work relaxation and transport of hot electrons in thin single crystalline metallic films is investigated by Ballistic Electron Emission Microscopy. The electron mean free paths are determined in an energy interval of 1 to 2 eV above the Fermi level. While fcc Au-films appear to be quite transmissive for hot electrons, the scattering lengths are much shorter for the ferromagnetic alloy FeCo revealing, furthermore, a strong spin asymmetry in hot electron transport. Additional information is gained from temperature dependent studies in combination with golden rule approaches in order to disentangle the impact of several relaxation and transport properties. It is found that bcc Fe-films are much less effective in spin filtering than films made of the FeCo-alloy. (orig.)

  9. Metal screen-film detector MTF at megavoltage x-ray energies.

    Science.gov (United States)

    Droege, R T; Bjärngard, B E

    1979-01-01

    The MTF of metal screen film detectors used in radiation treatment verification has been measured at 4 and 8 MV x-ray energies. The results show that lead screens provide better resolution than copper screens, and a single-emulsion film offers considerable advantage over the traditional double-emulsion film. A rear lead screen was found to seriously degrade the resolution properties of a front lead screen single-emulsion film detector. The detector MTF was found to be energy dependent. In general, both the low and the high spatial frequency response decreased with increasing x-ray energy. This, in part, accounts for the noticeable image quality difference between 4 and 8 MV radiographs.

  10. FTO films deposited in transition and oxide modes by magnetron sputtering using tin metal target.

    Science.gov (United States)

    Liao, Bo-Huei; Chan, Shih-Hao; Lee, Cheng-Chung; Kuo, Chien-Cheng; Chen, Sheng-Hui; Chiang, Donyau

    2014-02-01

    Fluorine-doped tin oxide (FTO) films were prepared by pulsed DC magnetron sputtering with a metal Sn target. Two different modes were applied to deposit the FTO films, and their respective optical and electrical properties were evaluated. In the transition mode, the minimum resistivity of the FTO film was 1.63×10(-3)  Ω cm with average transmittance of 80.0% in the visible region. Furthermore, FTO films deposited in the oxide mode and mixed simultaneously with H2 could achieve even lower resistivity to 8.42×10(-4)  Ω cm and higher average transmittance up to 81.1% in the visible region.

  11. EFFECT OF SMALL CLUSTER DIFFUSION DURING TWO-DIMENSIONAL THIN FILM GROWTH ON METAL SURFACE

    Institute of Scientific and Technical Information of China (English)

    WU FENG-MIN; LI QIAO-WEN; WU ZI-QIN

    2000-01-01

    The diffusion of small clusters such as dimers and trimers on metal surface and the growth of two-dimensional thin films are studied by Monte Carlo simulation, using realistic growth model and physical parameters. It is found that small cluster diffusion plays an important role in the process of thin film growth at not very low temperature. It affects not only the island density and the size of islands but also the critical value of saturation occurring during growth of thin films. The effect of small cluster diffusion depends on both the size of critical nucleus and the growth temperature.The simulation results also show that the larger the cluster allowed to diffuse, the easier the saturation that takes place,giving rise to the lower critical coverage of saturation occurring. It is suggested that the effect of small cluster diffusion should be included in establishing the growth models of thin films.

  12. 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...

  13. Large-Area Nanoparticle Films by Continuous Automated Langmuir-Blodgett Assembly and Deposition.

    Science.gov (United States)

    Li, Xue; Gilchrist, James F

    2016-02-09

    The operating parameters and resulting surface morphology of automated Langmuir-Blodgett deposition of monosized micrometer-scale silica colloids from an aqueous suspension are investigated. This apparatus allows continuous roll-to-roll deposition of particles into well-ordered arrays. The reproducible deposition of particle monolayers at low to moderate deposition rates at web speeds of less than 10 mm/s is possible and accurately characterized by a simple mass balance of particles deposited from solution. At faster deposition rates, Landau-Levich flow increases the film thickness such that flow instabilities hinder uniform particle deposition. A simple phase diagram outlines transitions from dispersed to multilayer coatings and from uniform to erratic deposition patterns. While the threshold of maximum deposition rate is well-defined for these conditions, changing operating parameters, particle size, and fluid viscosity and evaporation rate, the maximum speed can be increased significantly.

  14. The role of oxygen in the deposition of copper–calcium thin film as diffusion barrier for copper metallization

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zhinong, E-mail: znyu@bit.edu.cn [School of Optoelectronics and Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081 (China); Ren, Ruihuang [School of Optoelectronics and Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081 (China); Xue, Jianshe; Yao, Qi; Li, Zhengliang; Hui, Guanbao [Beijing BOE Optoelectronics Technology Co., Ltd, Beijing 100176 (China); Xue, Wei [School of Optoelectronics and Beijing Engineering Research Center of Mixed Reality and Advanced Display, Beijing Institute of Technology, Beijing 100081 (China)

    2015-02-15

    Highlights: • The CuCa film as the diffusion barrier of Cu film improves the adhesion of Cu film. • The introduction of oxygen into the deposition of CuCa film is necessary to improve the adhesion of Cu film. • The CuCa alloy barrier layer deposited at oxygen atmosphere has perfect anti-diffusion between Cu film and substrate. - Abstract: The properties of copper (Cu) metallization based on copper–calcium (CuCa) diffusion barrier as a function of oxygen flux in the CuCa film deposition were investigated in view of adhesion, diffusion and electronic properties. The CuCa film as the diffusion barrier of Cu film improves the adhesion of Cu film, however, and increases the resistance of Cu film. The introduction of oxygen into the deposition of CuCa film induces the improvement of adhesion and crystallinity of Cu film, but produces a slight increase of resistance. The increased resistance results from the partial oxidation of Cu film. The annealing process in vacuum further improves the adhesion, crystallinity and conductivity of Cu film. X-ray diffraction (XRD) and Auger electron spectroscopy (AES) show that the CuCa alloy barrier layer deposited at oxygen atmosphere has perfect anti-diffusion between Cu film and substrate due to the formation of Ca oxide in the interface of CuCa/substrate.

  15. ZnO buffer layer for metal films on silicon substrates

    Science.gov (United States)

    Ihlefeld, Jon

    2014-09-16

    Dramatic improvements in metallization integrity and electroceramic thin film performance can be achieved by the use of the ZnO buffer layer to minimize interfacial energy between metallization and adhesion layers. In particular, the invention provides a substrate metallization method utilizing a ZnO adhesion layer that has a high work of adhesion, which in turn enables processing under thermal budgets typically reserved for more exotic ceramic, single-crystal, or metal foil substrates. Embodiments of the present invention can be used in a broad range of applications beyond ferroelectric capacitors, including microelectromechanical systems, micro-printed heaters and sensors, and electrochemical energy storage, where integrity of metallized silicon to high temperatures is necessary.

  16. Magnetoelectric coupling effect in transition metal modified polycrystalline BiFeO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sreenivas Puli, Venkata, E-mail: pvsri123@gmail.com [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118 (United States); Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States); Kumar Pradhan, Dhiren [Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States); Gollapudi, Sreenivasulu [Department of Physics, Oakland University, Rochester, MI 48309-4401 (United States); Coondoo, Indrani [Department of Materials and Ceramic and CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Panwar, Neeraj [Department of Physics, Central University of Rajasthan, Bandar Sindri, Kishangarh 305801, Rajasthan (India); Adireddy, Shiva; Chrisey, Douglas B. [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118 (United States); Katiyar, Ram S. [Department of Physics and Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, PR 00936 (United States)

    2014-11-15

    Rare-earth (Sm) and transition metal (Co) modified polycrystalline BiFeO{sub 3} (BFO) thin films have been deposited on Pt/TiO{sub 2}/SiO{sub 2}/Si substrate successfully through pulsed laser deposition (PLD) technique. Piezoelectric, leakage current and temperature dependent dielectric and magnetic behaviour were investigated for the films. Typical “butterfly-shaped” loop were observed in BSFCO films with an effective piezoelectric constant (d{sub 33}) ∼94 pm/V at 0.6 MV/cm. High dielectric constant ∼900 and low dielectric loss ∼0.25 were observed at room temperature. M–H loops have shown relatively high saturation magnetization ∼35 emu/cm{sup 3} at a maximum field of H ∼20 kOe. Enhanced magnetoelectric coupling response is observed under applied magnetic field. The multiferroic, piezoelectric, leakage current behaviours were explored. Such studies should be helpful in designing multiferroic materials based on BSFCO films. - Highlights: • Transition metal modified polycrystalline BiFeO{sub 3} thin films prepared using PLD. • High ME-coupling response was observed in co-substituted BiFeO{sub 3} thin films. • High magnetization ∼35 emu/cm{sup 3} at a maximum field of H ∼20 kOe. • Low leakage current might be due to co-substitution in BiFeO{sub 3} thin films. • A notable piezoelectric constant d{sub 33} ∼94 pm/V was found in BiFeO{sub 3} thin films.

  17. Osteogenic activity and antibacterial effect of porous titanium modified with metal-organic framework films.

    Science.gov (United States)

    Chen, Junyu; Zhang, Xin; Huang, Chao; Cai, He; Hu, Shanshan; Wan, Qianbing; Pei, Xibo; Wang, Jian

    2017-03-01

    As a new class of crystalline nanoporous materials, metal-organic frameworks (MOFs) have recently been used for biomedical applications due to their large surface area, high porosity, and theoretically infinite structures. To improve the biological performance of titanium, MOF films were applied to surface modification of titanium. Zn-based MOF films composed of zeolitic imidazolate framework-8 (ZIF-8) crystals with nanoscale and microscale sizes (nanoZIF-8 and microZIF-8) were prepared on porous titanium surfaces by hydrothermal and solvothermal methods, respectively. The ZIF-8 films were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The nanoZIF-8 film exhibited good biocompatibility, whereas the microZIF-8 film showed obvious cytotoxicity to MG63 cells. Compared to pure titanium and alkali- and heat-treated porous titanium, the nanoZIF-8 film not only enhanced alkaline phosphatase (ALP) activity, extracellular matrix mineralization, and expression of osteogenic genes (ALP, Runx2) in MG63 cells but also inhibited the growth of Streptococcus mutans. These results indicate that MOF films or coatings may be promising candidates for bone tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 834-846, 2017.

  18. Electrodeposited porous metal oxide films with interconnected nanoparticles applied as anode of lithium ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Anguo, E-mail: hixiaoanguo@126.com; Zhou, Shibiao; Zuo, Chenggang; Zhuan, Yongbing; Ding, Xiang

    2014-12-15

    Highlights: • Highly porous NiO film is prepared by a co-electrodeposition method. • Porous NiO film is composed of interconnected nanoparticles. • Porous structure is favorable for fast ion/electron transfer. • Porous NiO film shows good lithium ion storage properties. - Abstract: Controllable synthesis of porous metal oxide films is highly desirable for high-performance electrochemical devices. In this work, a highly porous NiO film composed of interconnected nanoparticles is prepared by a simple co-electrodeposition method. The nanoparticles in the NiO film have a size ranging from 30 to 100 nm and construct large-quantity pores of 20–120 nm. As an anode material for lithium ion batteries, the highly porous NiO film electrode delivers a high discharge capacity of 700 mA h g{sup −1} at 0.2 C, as well as good high-rate performance. After 100 cycles at 0.2 C, a specific capacitance of 517 mA h g{sup −1} is attained. The good electrochemical performance is attributed to the interconnected porous structure, which facilitates the diffusion of ion and electron, and provides large reaction surface area leading to improved performance.

  19. Handshake electron transfer from hydrogen Rydberg atoms incident at a series of metallic thin films

    CERN Document Server

    Gibbard, Jemma A

    2016-01-01

    Thin metallic films have a 1D quantum well along the surface normal direction, which yields particle-in-a-box style electronic quantum states. However the quantum well is not infinitely deep and the wavefunctions of these states penetrate outside the surface where the electron is bound by its own image-charge attraction. Therefore a series of discrete, vacant states reach out from the thin film into the vacuum increasing the probability of electron transfer from an external atom or molecule to the thin film, especially for the resonant case where the quantum well energy matches that of the Rydberg atom. We show that `handshake' electron transfer from a highly excited Rydberg atom to these thin-film states is experimentally measurable. Thicker films, have a wider 1D box, changing the energetic distribution and image-state contribution to the thin film wavefunctions, resulting in more resonances. Calculations successfully predict the number of resonances and the nature of the thin-film wavefunctions for a given...

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

    Science.gov (United States)

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

    2013-11-01

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

  1. Spreading of thin-film metal patterns deposited on nonplanar surfaces using a shadow mask micromachined in si (110)

    NARCIS (Netherlands)

    Tiggelaar, R.M.; Berenschot, J.W.; Elwenspoek, M.C.; Gardeniers, J.G.E.; Dorsman, R.; Kleijn, C.R.

    2007-01-01

    The application of a three dimensional, self-aligning shadow mask in (110)-oriented silicon for thin-film metal deposition is discussed. This shadow mask is used for the deposition of metal tracks on the bottom of structures with vertical sidewalls, i.e., the patterning of metal catalytic patches un

  2. Method for nanomodulation of metallic thin films following the replica-antireplica process based on porous alumina membranes

    Science.gov (United States)

    Palma, J. L.; Denardin, J. C.; Escrig, J.

    2017-03-01

    In this paper we have introduced a method for modulation of metallic thin films by sputtering of metals on anodized aluminum templates. Using a high deposition rate during deposition of the non-magnetic metal on the Al pattern, we have separated the two metallic surfaces and, thus, imprinted a pattern of nanohills on a non-magnetic metallic film, such as Au, Ag or Cu. The morphology of the nanostructured metallic films was determined by scanning electron microscopy. Thus, we have confirmed that the ordering degree of the Al template remained after the replication process. Additionally, and as an example of use of these films, we have prepared Supermalloy thin films deposited by sputtering onto these nanostructured non-magnetic metals. The room temperature magnetic behavior of these thin films is also studied. Interestingly, we have found that when the external magnetic field is applied out of plane of the substrate, the coercivity increases linearly as we increase the radius of the nanohills. These soft magnetic films can open new opportunities for magnetic field sensor applications.

  3. Quasi continuous-wave lasing in organic thin-film semiconductors (Conference Presentation)

    Science.gov (United States)

    Sanadanayaka, Atula S. D.; Yoshida, Kou; Ribierre, Jean-Charles; Matsushima, Toshinori; Adachi, Chihaya

    2016-09-01

    Since the discovery of organic solid-state lasers, great efforts have been devoted to the development of continuous-wave (cw) lasing in organic materials. However, the operation of organic solid-state lasers under optical cw excitation or pulse excitation at a very high repetition rate (quasi-cw excitation) is extremely challenging. In this work, we have demonstrated quasi-continuous-wave (quasi-cw) surface-emitting lasing in a distributed feedback device which combines a second-order grating with an organic thin film of a host material 4,4'-bis(N-carbazolyl)-1,1'-biphenyl (CBP) blended with an organic laser dye 4,4'-bis[(N-carbazole)styryl]biphenyl (BSBCz). When pumping the device with optical picosecond pulse excitation, the quasi-cw laser operation maintained up to a repetition rate of 8 MHz. The lasing threshold was around 0.25 μJ cm-2 which was almost independent of the repetition rates. For our laser devices, the maximum repetition rate (8 MHz) is the highest ever reported, and the lasing threshold (0.25 μJ cm-2) is the lowest ever reported. These superior quasi-cw lasing characteristics in BSBCz are accomplished by the less generation of triplet excitons via intersystem crossing because a photoluminescence quantum yield of the blend film is nearly 100% and there is no significant spectral overlap between laser and triplet absorption.[1,2] Triplet quenchers, generally used for the fabrication of organic thin-film lasers, were not necessary in our devices because of negligible accumulation of triplet excitons and a small spectral overlap between emission and triplet absorption. Therefore, we believe that BSBCz is the most promising candidate for the first realization of electrically pumped organic laser diodes in terms of optical characteristics. However, electrical characteristics such as charge carrier mobility, charge carrier capture cross section, etc., are also extremely important and will need further investigation and enhancement for realization of

  4. Ductility of metal thin films in flexible electronics

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Flexible, large area electronics using various organic and inorganic materials are beginning to show great promise. During manufacture and service, large deforma- tion of these hybrid materials will pose significant challenges in terms of high performance and reliability. A deep understanding of the ductility or flexibility of macroelectronics becomes one of the major issues that must be addressed ur- gently. This paper describes the current level of understanding on the thin-film ductility, both free-standing and substrate-supported, and relevant influencing factors.

  5. Thin films of molecular metals TTF-TCNQ

    CERN Document Server

    Fraxedas, J; Figueras, A; Jimenez, I; Gago, R; Auban-Senzier, P; Goffman, M

    2002-01-01

    We present recent results on the characterization of highly ordered polycrystalline thin films of the charge transfer salt TTF-TCNQ (TTF=tetrathiafulvalene, TCNQ=tetracyanoquinodimethane) prepared by thermal sublimation in high vacuum under different conditions. The increase in orientation and microcrystal size as a function of substrate and annealing temperatures is addressed. A consequence of such an increase is the reduction of the conductivity activation energy, which eventually leads to the observation of the Peierls transition by resistivity measurements. X-ray absorption near edge spectroscopy studies performed with synchrotron radiation reveal directly the influence of charge transfer on unoccupied states near the Fermi level.

  6. Lithographically patterned nanowire electrodeposition: a method for patterning electrically continuous metal nanowires on dielectrics.

    Science.gov (United States)

    Xiang, Chenxiang; Kung, Sheng-Chin; Taggart, David K; Yang, Fan; Thompson, Michael A; Güell, Aleix G; Yang, Yongan; Penner, Reginald M

    2008-09-23

    Lithographically patterned nanowire electrodeposition (LPNE) is a new method for fabricating polycrystalline metal nanowires using electrodeposition. In LPNE, a sacrificial metal (M(1)=silver or nickel) layer, 5-100 nm in thickness, is first vapor deposited onto a glass, oxidized silicon, or Kapton polymer film. A (+) photoresist (PR) layer is then deposited, photopatterned, and the exposed Ag or Ni is removed by wet etching. The etching duration is adjusted to produce an undercut approximately 300 nm in width at the edges of the exposed PR. This undercut produces a horizontal trench with a precisely defined height equal to the thickness of the M(1) layer. Within this trench, a nanowire of metal M(2) is electrodeposited (M(2)=gold, platinum, palladium, or bismuth). Finally the PR layer and M(1) layer are removed. The nanowire height and width can be independently controlled down to minimum dimensions of 5 nm (h) and 11 nm (w), for example, in the case of platinum. These nanowires can be 1 cm in total length. We measure the temperature-dependent resistance of 100 microm sections of Au and Pd wires in order to estimate an electrical grain size for comparison with measurements by X-ray diffraction and transmission electron microscopy. Nanowire arrays can be postpatterned to produce two-dimensional arrays of nanorods. Nanowire patterns can also be overlaid one on top of another by repeating the LPNE process twice in succession to produce, for example, arrays of low-impedance, nanowire-nanowire junctions.

  7. Advantageous use of metallic cobalt in the target for pulsed laser deposition of cobalt-doped ZnO films

    Science.gov (United States)

    Ying, Minju; Blythe, Harry J.; Dizayee, Wala; Heald, Steve M.; Gerriu, Fatma M.; Fox, A. Mark; Gehring, Gillian A.

    2016-08-01

    We investigate the magnetic properties of ZnCoO thin films grown by pulsed laser deposition (PLD) from targets made containing metallic Co or CoO precursors instead of the usual Co3O4. We find that the films grown from metallic Co precursors in an oxygen rich environment contain negligible amounts of Co metal and have a large magnetization at room temperature. Structural analysis by X-ray diffraction and magneto-optical measurements indicate that the enhanced magnetism is due, in part, from Zn vacancies that partially compensate the naturally occurring n-type defects. We conclude that strongly magnetic films of Zn0.95Co0.05O that do not contain metallic cobalt can be grown by PLD from Co-metal-precursor targets if the films are grown in an oxygen atmosphere.

  8. ARTICLES: Metal Precursor Influence on Performance of Culn1-xGaxSe2 Films

    Science.gov (United States)

    Wang, Man; Zhang, Zhong-wei; Jiang, Guo-shun; Zhu, Chang-fei

    2010-06-01

    CuIn1-xGaxSe2 (CIGS) films were prepared by a two-stage method, in which Cu-In-Ga metallic precursors were firstly deposited on unheated Mo-coated soda lime glass substrates by direct current sputtering CuGa (20%Ga) and radio frequency sputtering In targets in an Ar atmosphere, followed by selenization at 520 °C for 40 min in Se vapor. By adjusting the sputtering thickness ratio of surface CuGa (20%Ga) and bottom CuGa (20%Ga) alloy layers in metal precursor, different CIGS thin films were fabricated. Through X-ray diffraction spectra, Raman spectra, local energy dispersive spectrometer, planar- and cross-sectional views of scanning electron microscopy measurements, it revealed that the CIGS thin films from selenization of metal precursor with CuGa:In:CuGa thickness ratio of 7:20:3 (sample-2-se) was of chalcopyrite structure with the preferred (112) orientation, and the grains sizes ranged from 0.5 μm to 2 μm, and sample-2-se had no binary compound phase of In-Se and order defect compound phase. Consequently, the results of illuminated current-voltage curve and quantum efficiency measurements showed that the CIGS film device made from sample-2-se had relative higher photo-electric conversion efficiency (3.59%) and good spectrum response.

  9. Investigation of the removal of heavy metals from sediments using rhamnolipid in a continuous flow configuration.

    Science.gov (United States)

    Dahrazma, Behnaz; Mulligan, Catherine N

    2007-10-01

    Heavy metal contamination of sediments is hazardous to benthic organisms and needs more attention in order to prevent entry of these heavy metals into the food chain. Biosurfactants have shown the capability to remove heavy metals from soils and sediments. The objective of this research was to evaluate the performance of rhamnolipid, a glycolipid biosurfactant, in a continuous flow configuration (CFC) for removal of heavy metals (copper, zinc, and nickel) from the sediments taken from Lachine Canal, Canada, to simulate a flow through remediation technique. In this configuration, rhamnolipid solution with a constant rate was passed through the sediment sample within a column. Important parameters such as the concentration of rhamnolipid and the additives, time and the flow rate were investigated. The removal of heavy metals from sediments was up to 37% of Cu, 13% of Zn, and 27% of Ni when rhamnolipid without additives was applied. Adding 1% NaOH to 0.5% rhamnolipid improved the removal of copper by up to 4 times compared with 0.5% rhamnolipid alone. This information is valuable for designing a remediation protocol for sediment washing.

  10. Thin graphite films formation by carbon precipitation in metals: diffusion approach

    Science.gov (United States)

    Shvets, Petr V.; Obraztsov, Alexander N.

    2016-03-01

    Thin graphite films attract significant interest due to their unique physical properties and potential applications. Chemical vapor deposition in the presence of metal catalysts is one of the most promising and widely used techniques to produce these films. There are many experimental works devoted to the material synthesis; however, the results are usually obtained by the trial-and-error method without a proper understanding of the processes behind the experiment. We theoretically analyze the carbon diffusion processes inside a metal substrate during the deposition. The theory allows interconnection of the deposition parameters with the thickness of produced graphite films. Numerically solving the diffusion equations for the real systems, we obtained a good correlation between simulations and experimental data. Based on our simulations, we made some conclusions about the formation of graphite films by the precipitation process. The numerical simulations were mostly done for the popular nickel substrates, but we also made some calculations for iron, showing that it also could be used to form thin graphite films under certain conditions.

  11. Metal-insulator transition in epitaxial NdNiO3 thin film: A structural, electrical and optical study

    Science.gov (United States)

    Shao, Tao; Qi, Zeming; Wang, Yuyin; Li, Yuanyuan; Yang, Mei; Hu, Chuansheng

    2017-03-01

    NdNiO3 thin film has been prepared by pulsed laser deposition on LaAlO3 (001) single crystalline substrate. Temperature-dependent resistivity measurement shows a sharp metal-insulator transition in such thin film. The phase transition temperature can be tuned from 90 K to 121 K by changing the thickness of thin film. The structure evolution during phase transition is studied by Raman spectroscopy. Optical conductivity reveals that the variation carrier density in the process of phase transition. The results of structural, electrical and optical studies provide useful insights to understand the mechanism of metal-insulator transition of NdNiO3 thin film.

  12. Transparent electrode designs based on optimal nano-patterning of metallic films

    KAUST Repository

    Catrysse, Peter B.

    2010-09-10

    Transparent conductive electrodes are critical to the operation of optoelectronic devices, such as photovoltaic cells and light emitting diodes. Effective electrodes need to combine excellent electrical and optical properties. Metal oxides, such as indium tin oxide, are commonly used. There is substantial interest in replacing them, however, motivated by practical problems and recent discoveries regarding the optics of nano-patterned metals. When designing nano-patterned metallic films for use as electrodes, one needs to account for both optical and electrical properties. In general, it is insufficient to optimize nano-structured films based upon optical properties alone, since structural variations will also affect the electrical properties. In this work, we investigate the need for simultaneous optical and electrical performance by analyzing the optical properties of a class of nano-patterned metallic electrodes that is obtained by a constant-sheet-resistance transformation. Within such a class the electrical and optical properties can be separated, i.e., the sheet resistance can be kept constant and the transmittance can be optimized independently. For simple one-dimensional periodic patterns with constant sheet-resistance, we find a transmission maximum (polarization-averaged) when the metal sections are narrow (< 40 nm, ~ 10% metal fill-factor) and tall (> 100 nm). Our design carries over to more complex two-dimensional (2D) patterns. This is significant as there are no previous reports regarding numerical studies on the optical and electrical properties of 2D nano-patterns in the context of electrode design.

  13. Electronic structure and conductivity of nanocomposite metal (Au,Ag,Cu,Mo)-containing amorphous carbon films

    Energy Technology Data Exchange (ETDEWEB)

    Endrino, Jose L.; Horwat, David; Gago, Raul; Andersson, Joakim; Liu, Y.S.; Guo, Jinghua; Anders, Andre

    2008-05-14

    In this work, we study the influence of the incorporation of different metals (Me = Au, Ag, Cu, Mo) on the electronic structure of amorphous carbon (a-C:Me) films. The films were produced at room temperature using a novel pulsed dual-cathode arc deposition technique. Compositional analysis was performed with secondary neutral mass spectroscopy whereas X-ray diffraction was used to identify the formation of metal nanoclusters in the carbon matrix. The metal content incorporated in the nanocomposite films induces a drastic increase in the conductivity, in parallel with a decrease in the band gap corrected from Urbach energy. The electronic structure as a function of the Me content has been monitored by x-ray absorption near edge structure (XANES) at the C K-edge. XANES showed that the C host matrix has a dominant graphitic character and that it is not affected significantly by the incorporation of metal impurities, except for the case of Mo, where the modifications in the lineshape spectra indicated the formation of a carbide phase. Subtle modifications of the spectral lineshape are discussed in terms of nanocomposite formation.

  14. Intrinsic and interfacial effect of electrode metals on the resistive switching behaviors of zinc oxide films.

    Science.gov (United States)

    Xue, W H; Xiao, W; Shang, J; Chen, X X; Zhu, X J; Pan, L; Tan, H W; Zhang, W B; Ji, Z H; Liu, G; Xu, X-H; Ding, J; Li, R-W

    2014-10-24

    Exploring the role of electrode metals on the resistive switching properties of metal electrode/oxide/metal electrode sandwiched structures provides not only essential information to understand the underlying switching mechanism of the devices, but also useful guidelines for the optimization of the switching performance. A systematic study has been performed to investigate the influence of electrodes on the resistive switching characteristics of zinc oxide (ZnO) films in this contribution, in terms of both the intrinsic and interfacial effects. It has been found that the low-resistance state resistances (Ω(LRS)) of all the investigated devices are below 50 Ω, which can be attributed to the formation of highly conductive channels throughout the ZnO films. On the other hand, the high-resistance state resistances (Ω(HRS)) depend on the electronegativity and ionic size of the employed electrode metals. Devices with electrode metals of high electronegativity and large ionic size possess high Ω(HRS) values, while those with electrode metals of low electronegativity and small ionic size carry low Ω(HRS) values. A similar trend of the set voltages has also been observed, while the reset voltages are all distributed in a narrow range close to ±0.5 V. Moreover, the forming voltages of the switching devices strongly depend on the roughness of the metal/ZnO and/or ZnO/metal interface. The present work provides essential information for better understanding the switching mechanism of zinc oxide based devices, and benefits the rational selection of proper electrode metals for the device performance optimization.

  15. Preparation and analysis of anodic aluminum oxide films with continuously tunable interpore distances

    Science.gov (United States)

    Qin, Xiufang; Zhang, Jinqiong; Meng, Xiaojuan; Deng, Chenhua; Zhang, Lifang; Ding, Guqiao; Zeng, Hao; Xu, Xiaohong

    2015-02-01

    Nanoporous anodic aluminum oxides are often used as templates for preparation of nanostructures such as nanodot, nanowire and nanotube arrays. The interpore distance of anodic aluminum oxide is the most important parameter in controlling the periodicity of these nanostructures. Herein we demonstrate a simple and yet powerful method to fabricate ordered anodic aluminum oxides with continuously tunable interpore distances. By using mixed solution of citric and oxalic acids with different molar ratio, the range of anodizing voltages within which self-ordered films can be formed were extended to between 40 and 300 V, resulting in the interpore distances change from 100 to 750 nm. Our work realized very broad range of interpore distances in a continuously tunable fashion and the experiment processes are easily controllable and reproducible. The dependence of the interpore distances on acid ratios in mixed solutions was discussed through analysis of anodizing current and it was found that the effective dissociation constant of the mixed acids is of great importance. The interpore distances achieved are comparable to wavelengths ranging from UV to near IR, and may have potential applications in optical meta-materials for photovoltaics and optical sensing.

  16. Nanogroove array on thin metallic film as planar lens with tunable focusing

    CERN Document Server

    Wellems, L David; Leskova, T A; Maradudin, A A

    2012-01-01

    Numerical results for the distributions of light transmitted through metallic planar lenses composed of symmetric nanogroove arrays on the surfaces of a gold film are presented and explained. Both the near- and far-field distributions of the intensity of light transmitted are calculated by using a Green's function formalism. Results for an optimal transverse focus based on a quadratic variation of groove width are obtained. Meanwhile, a significant dependence of the focal length on the wavelength of light incident from the air side through the gold film into a dielectric substrate is found for this detector configuration.

  17. Cherenkov terahertz surface plasmon excitation by an electron beam over an ultrathin metal film

    Science.gov (United States)

    Kumar, Pawan; Kumar, Rajeev; Rajouria, Satish Kumar

    2016-12-01

    The mechanism of Cherenkov excitation of terahertz (THz) surface plasma wave (SPW), by a relativistic electron beam propagating over an ultrathin metal film deposited on glass, is investigated. The SPW field falls off exponentially in vacuum as well as glass, while the surface plasmon resonant frequency is lowered by the reduction of film thickness. The SPW field causes density bunching of the beam leading to current modulation and generation of THz radiation via the Cherenkov interaction. The frequency of the THz decreases with the energy of the beam, whereas the growth rate increases.

  18. Electron field emission from 2-induced insulating to metallic behaviour of amorphous carbon (-C) films

    Indian Academy of Sciences (India)

    Pitamber Mahanandia; P N Viswakarma; Prasad Vishnu Bhotla; S V Subramanyam; Karuna Kar Nanda

    2010-06-01

    The influence of concentration and size of 2 cluster on the transport properties and electron field emissions of amorphous carbon films have been investigated. The observed insulating to metallic behaviour from reduced activation energy derived from transport measurement and threshold field for electron emission of -C films can be explained in terms of improvements in the connectivity between 2 clusters. The connectivity is resulted by the cluster concentration and size. The concentration and size of 2 content cluster is regulated by the coalescence of carbon globules into clusters, which evolves with deposition conditions.

  19. Multi-Objective Optimization of Thin-Film Silicon Solar Cells with Metallic and Dielectric Nanoparticles

    Directory of Open Access Journals (Sweden)

    Giovanni Aiello

    2017-01-01

    Full Text Available Thin-film solar cells enable a strong reduction of the amount of silicon needed to produce photovoltaic panels but their efficiency lowers. Placing metallic or dielectric nanoparticles over the silicon substrate increases the light trapping into the panel thanks to the plasmonic scattering from nanoparticles at the surface of the cell. The goal of this paper is to optimize the geometry of a thin-film solar cell with silver and silica nanoparticles in order to improve its efficiency, taking into account the amount of silver. An efficient evolutionary algorithm is applied to perform the optimization with a reduced computing time.

  20. Beam Focusing by a Non-Uniformly-Spaced Nanoslit Array in a Metallic Film

    Institute of Scientific and Technical Information of China (English)

    JIAO Xiao-Jin; WANG Pei; ZHANG Dou-Guo; LU Yong-Hua; XIE Jian-Ping; MING Hai

    2006-01-01

    @@ A finite difference time domain simulation has been performed to analyse the optical transmission through a non-uniformly-spaced nanoslit array in silver film. The phase change of surface plasmons propagating on the silver film is used to modulate the initial phase of the output beam. The beam deflection and focusing function are designed, and the focal depth of the focusing metallic structure are mainly considered. It is found that the focal depth can be controlled by altering the effective width of this structure, i.e. the number of slits, when the relative spacing is fixed.

  1. Wake effects of a charged projectile flying above a magnetized metal film

    Science.gov (United States)

    Jafari, M. R.

    2017-03-01

    This research deals with covering of a metal film on the semi-infinite dielectric in the presence of a weak external magnetic field. A charged projectile has been considered flying above the thin film. The surface wave frequencies of the system were derived by means of the quantum hydrodynamic theory through the appropriate boundary conditions. The energy loss of charged particle in the present system was also investigated. It is found that the external magnetic field modifies the distribution of electron gas density as well as the energy loss of flying charged particle.

  2. Nondestructive inspection of organic films on sandblasted metals using diffuse reflectance infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Powell, G.L. [Oak Ridge Y-12 Plant, TN (United States); Cox, R.L. [Oak Ridge National Lab., TN (United States); Barber, T.E. [Sam Houston State Univ., Huntsville, TX (United States); Neu, J.T. [Surface Optics Corp., San Diego, CA (United States)

    1996-07-08

    Diffuse reflectance infrared spectroscopy is a very useful tool for the determination of surface contamination and characterization of films in manufacturing applications. Spectral data from the surfaces of a host of practical materials may be obtained with sufficient insensitivity to characterize relatively thick films, such as paint, and the potential exists to detect very thin films, such as trace oil contamination on metals. The SOC 400 Surface Inspection Machine/InfraRed (SIMIR) has been developed as a nondestructive inspection tool to exploit this potential in practical situations. This SIMIR is a complete and ruggidized Fourier transform infrared spectrometer with a very efficient and robust barrel ellipse diffuse reflectance optical collection system and operating software system. The SIMIR weighs less than 8 Kg, occupies less than 14 L volume, and may be manipulated into any orientation during operation. The surface to be inspected is placed at the focal point of the SIMIR by manipulating the SIMIR or the surface. The SIMIR may or may not contact the surface being inspected. For flat or convex items, there are no size limits to items being inspected. For concave surfaces, the SIMIR geometry limits the surface to those having a radius of curvature greater than 0.2 m. For highly reflective metal surfaces, the SIMIR has a noise level approaching 1 {times} 10{sup {minus}4} absorbance units, which is sufficient for detecting nanometer thick organic film residues on metals. The use of this nondestructive inspection tool is demonstrated by the spatial mapping of organic stains on sand blasted metals in which organic stains such as silicone oils, mineral oils, and triglycerides are identified both qualitatively and quantitatively over the surface of the metal specimen.

  3. Low-Temperature UV-Assisted Fabrication of Metal Oxide Thin Film Transistor

    Science.gov (United States)

    Zhu, Shuanglin

    Solution processed metal oxide semiconductors have attracted intensive attention in the last several decades and have emerged as a promising candidate for the application of thin film transistor (TFT) due to their nature of transparency, flexibility, high mobility, simple processing technique and potential low manufacturing cost. However, metal oxide thin film fabricated by solution process usually requires a high temperature (over 300 °C), which is above the glass transition temperature of some conventional polymer substrates. In order to fabricate the flexible electronic device on polymer substrates, it is necessary to find a facile approach to lower the fabrication temperature and minimize defects in metal oxide thin film. In this thesis, the electrical properties dependency on temperature is discussed and an UV-assisted annealing method incorporating Deep ultraviolet (DUV)-decomposable additives is demonstrated, which can effectively improve electrical properties solution processed metal oxide semiconductors processed at temperature as low as 220 °C. By studying a widely used indium oxide (In2O3) TFT as a model system, it is worth noted that compared with the sample without UV treatment, the linear mobility and saturation mobility of UV-annealing sample are improved by 56% and 40% respectively. Meanwhile, the subthreshold swing is decreased by 32%, indicating UV-treated device could turn on and off more efficiently. In addition to pure In2O3 film, the similar phenomena have also been observed in indium oxide based Indium-Gallium-Zinc Oxide (IGZO) system. These finding presented in this thesis suggest that the UV assisted annealing process open a new route to fabricate high performance metal oxide semiconductors under low temperatures.

  4. Sputter deposition of transition-metal carbide films — A critical review from a chemical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Jansson, Ulf, E-mail: ulf.jansson@kemi.uu.se [Department of Chemistry, Ångström, Uppsala Universitet (Sweden); Lewin, Erik [Laboratory for Nanoscale Materials Science, Empa (Switzerland); Department of Chemistry, Ångström, Uppsala Universitet (Sweden)

    2013-06-01

    Thin films based on transition-metal carbides exhibit many interesting physical and chemical properties making them attractive for a variety of applications. The most widely used method to produce metal carbide films with specific properties at reduced deposition temperatures is sputter deposition. A large number of papers in this field have been published during the last decades, showing that large variations in structure and properties can be obtained. This review will summarise the literature on sputter-deposited carbide films based on chemical aspects of the various elements in the films. By considering the chemical affinities (primarily towards carbon) and structural preferences of different elements, it is possible to understand trends in structure of binary transition-metal carbides and the ternary materials based on these carbides. These trends in chemical affinity and structure will also directly affect the growth process during sputter deposition. A fundamental chemical perspective of the transition-metal carbides and their alloying elements is essential to obtain control of the material structure (from the atomic level), and thereby its properties and performance. This review covers a wide range of materials: binary transition-metal carbides and their nanocomposites with amorphous carbon; the effect of alloying carbide-based materials with a third element (mainly elements from groups 3 through 14); as well as the amorphous binary and ternary materials from these elements deposited under specific conditions or at certain compositional ranges. Furthermore, the review will also emphasise important aspects regarding materials characterisation which may affect the interpretation of data such as beam-induced crystallisation and sputter-damage during surface analysis.

  5. Electrical Conduction Mechanisms in Metal-Insulator-Metal (MIM) Structure with TiO x N y Thin Films Deposited with Different O/N Ratios

    Science.gov (United States)

    Libardi, Juliano; Grigorov, Korneli G.; Moraes, Rodrigo S.; Guerino, Marciel; Da Silva Sobrinho, Argemiro S.; Massi, Marcos

    2015-01-01

    In this work, the current-voltage characteristics of titanium oxynitride thin films were measured and the charge carrier transport mechanisms established as a function of film composition. The films were deposited by magnetron sputtering, where the oxygen/nitrogen ratio was varied via a pulsing technique to enable the achievement of desired concentrations. Thus, the obtained films showed metallic titanium nitrate (TiN) or semiconductor titanium dioxide (TiO2) character and were used to fabricate metal-insulator-metal structures. An ohmic conduction mechanism was identified in the films with higher nitrogen incorporation or presenting TiN-rich phase. Decrease in the nitrogen content resulted in films with TiO2-rich phase. In this case, Poole-Frenkel and space-charge-limited current conduction mechanisms were observed. The dielectric constants were calculated from the high-frequency capacitance-voltage dependences, with a reduction from 10 to 3 being observed due to the stoichiometric changes and probable incorporation of defects into the film structure. Finally, the film composition and structural characteristics of the films were revealed by Rutherford backscattering and x-ray diffraction techniques, respectively.

  6. Gelation Mechanisms and Characterization of Electrochemically Generated Protein Films at Metal Interfaces

    Science.gov (United States)

    Martin, Elizabeth J.

    Although the electrochemical behavior of metals used in orthopedic implants has been studied extensively, the material interactions with proteins during corrosion processes remains poorly understood. Some studies suggest that metal-protein interactions accelerate corrosion, while others suggest that proteins protect the material from degradation. Corrosion of implant materials is a major concern due to the metal ion release that can sometimes cause adverse local tissue reactions and ultimately, failure of the implant. The initial purpose of this research was therefore to study the corrosion behavior of CoCrMo, an alloy commonly used in hip replacements, with a quartz crystal microbalance (QCM) in physiologically relevant media. The QCM enables in situ characterization of surface changes accompanying corrosion and is sensitive to viscoelastic effects at its surface. Results of QCM studies in proteinaceous media showed film deposition on the alloy surface under electrochemical conditions that otherwise produced mass loss if proteins were not present in the electrolyte. Additional studies on pure Co, Cr, and Mo demonstrated that the protein films also form on Mo surfaces after a release of molybdate ions, suggesting that these ions are essential for film formation. The electrochemically generated protein films are reminiscent of carbonaceous films that form on implant surfaces in vivo, therefore a second goal of the research was to delineate mechanisms that cause the films to form. In the second stage of this research, electrochemical QCM tests were conducted on models of the CoCrMo system consisting of Cr electrodes in proteinaceous or polymeric media containing dissolved molybdate ions. Studies indicated that films can be generated through electrochemical processes so long as both amine functional groups and molybdate ions are present in the electrolyte solution. These results suggest that the films form due to an ionic cross-linking reaction between the positively

  7. The Integrity bare-metal stent made by continuous sinusoid technology.

    Science.gov (United States)

    Turco, Mark A

    2011-05-01

    The Integrity Coronary Stent System (Medtronic Vascular, CA, USA) is a low-profile, open-cell, cobalt-chromium-alloy advanced bare-metal iteration of the well-known Driver/Micro-Driver Coronary Stent System (Medtronic Vascular). The Integrity stent is made with a process called continuous sinusoid technology. This process allows stent construction via wrapping a single thin strand of wire around a mandrel in a sinusoid configuration, with laser fusion of adjacent crowns. The wire-forming process and fusion pattern provide the stent with a continuous preferential bending plane, intended to allow easier access to, and smoother tracking within, distal and tortuous vessels while radial strength is maintained. Continuous sinusoid technology represents innovation in the design of stent platforms and will provide a future stent platform for newer technology, including drug-eluting stent platforms, drug-filled stents and core wire stents.

  8. Guest-Induced Two-Way Structural Transformation in a Layered Metal-Organic Framework Thin Film.

    Science.gov (United States)

    Haraguchi, Tomoyuki; Otsubo, Kazuya; Sakata, Osami; Fujiwara, Akihiko; Kitagawa, Hiroshi

    2016-12-28

    Fabrication of thin films made of metal-organic frameworks (MOFs) has been intensively pursued for practical applications that use the structural response of MOFs. However, to date, only physisorption-induced structural response has been studied in these films. Chemisorption can be expected to provide a remarkable structural response because of the formation of bonds between guest molecules and reactive metal sites in host MOFs. Here, we report that chemisorption-induced two-way structural transformation in a nanometer-sized MOF thin film. We prepared a two-dimensional layered-type MOF Fe[Pt(CN)4] thin film using a step-by-step approach. Although the as-synthesized film showed poor crystallinity, the dehydrated form of this thin film had a highly oriented crystalline nature (Film-D) as confirmed by synchrotron X-ray diffraction (XRD). Surprisingly, under water and pyridine vapors, Film-D showed chemisorption-induced dynamic structural transformations to Fe(L)2[Pt(CN)4] thin films [L = H2O (Film-H), pyridine (Film-P)], where water and pyridine coordinated to the open Fe(2+) site. Dynamic structural transformations were also confirmed by in situ XRD, sorption measurement, and infrared reflection absorption spectroscopy. This is the first report of chemisorption-induced dynamic structural response in a MOF thin film, and it provides useful insights, which would lead to future practical applications of MOFs utilizing chemisorption-induced structural responses.

  9. Suppression of continuous lasing in a carbon nanotube polyimide film mode-locked erbium-doped fiber laser.

    Science.gov (United States)

    Gui, Lili; Yang, Xin; Zhao, Guangzhen; Yang, Xu; Xiao, Xiaosheng; Zhu, Jinsong; Yang, Changxi

    2011-01-01

    We demonstrated an erbium-doped mode-locked fiber laser using a single-walled carbon nanotube-dispersed polyimide (SWNT-PI) film. Different mode-locking operations were compared and analyzed utilizing SWNT-PI films with different concentrations (2, 1, and 0.25 wt.%, respectively). It was found that the continuous single-pulse mode-locking operation was often accompanied by a continuous wave oscillation part for the 1 and 0.25 wt.% SWNT-PI films, whereas the 2 wt.% SWNT-PI film presented the most excellent mode-locking performance, thanks to sufficient modulation depth. Using the 2 wt.% SWNT-PI film, a stable pulse train with a pulse width of 840 fs and a repetition rate of 15.3 MHz was achieved. The average output power was 0.33 mW at the pump power of 155 mW under an output coupling ratio of 10%. Operational performance of the laser cavity when employing the 2 wt.% SWNT-PI film was also demonstrated.

  10. Erosion of mylar and protection by thin metal films

    Science.gov (United States)

    Fraundorf, P.; Lindstrom, D.; Sandford, S.; Swan, P.; Walker, R.; Zinner, E.; Pailer, N.

    1983-01-01

    Mylar strips, 2.5 microns thick, uncoated and coated with 50A, 100A and 200A of Al, Pd, and Au/Pd were exposed on STS-5 in order to measure the erosion of mylar and to test means of protecting thin plastic foils commonly used for space experiments in low earth orbit. Analysis by optical microscopy, SEM and STEM investigation, EDX measurements, FTIR spectroscopy and weight loss measurements showed that while up to 75 percent of the uncoated mylar was eroded during exposure, thin coatings of the above metals can protect mylar for integrated oxygen-fluxes of at least 10 to the 21st atoms/sq cm.

  11. Fullerenes as adhesive layers for mechanical peeling of metallic, molecular and polymer thin films.

    Science.gov (United States)

    Wieland, Maria B; Slater, Anna G; Mangham, Barry; Champness, Neil R; Beton, Peter H

    2014-01-01

    We show that thin films of C60 with a thickness ranging from 10 to 100 nm can promote adhesion between a Au thin film deposited on mica and a solution-deposited layer of the elastomer polymethyldisolaxane (PDMS). This molecular adhesion facilitates the removal of the gold film from the mica support by peeling and provides a new approach to template stripping which avoids the use of conventional adhesive layers. The fullerene adhesion layers may also be used to remove organic monolayers and thin films as well as two-dimensional polymers which are pre-formed on the gold surface and have monolayer thickness. Following the removal from the mica support the monolayers may be isolated and transferred to a dielectric surface by etching of the gold thin film, mechanical transfer and removal of the fullerene layer by annealing/dissolution. The use of this molecular adhesive layer provides a new route to transfer polymeric films from metal substrates to other surfaces as we demonstrate for an assembly of covalently-coupled porphyrins.

  12. Heat capacity measurements of atoms and molecules adsorbed on evaporated metal films

    Energy Technology Data Exchange (ETDEWEB)

    Kenny, T.W.

    1989-05-01

    Investigations of the properties of absorbed monolayers have received great experimental and theoretical attention recently, both because of the importance of surface processes in practical applications such as catalysis, and the importance of such systems to the understanding of the fundamentals of thermodynamics in two dimensions. We have adapted the composite bolometer technology to the construction of microcalorimeters. For these calorimeters, the adsorption substrate is an evaporated film deposited on one surface of an optically polished sapphire wafer. This approach has allowed us to make the first measurements of the heat capacity of submonolayer films of /sup 4/He adsorbed on metallic films. In contrast to measurements of /sup 4/He adsorbed on all other insulating substrates, we have shown that /sup 4/He on silver films occupies a two-dimensional gas phase over a broad range of coverages and temperatures. Our apparatus has been used to study the heat capacity of Indium flakes. CO multilayers, /sup 4/He adsorbed on sapphire and on Ag films and H/sub 2/ adsorbed on Ag films. The results are compared with appropriate theories. 68 refs., 19 figs.

  13. Preparation of metal-organic decomposition-derived strontium zirconate dielectric thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chen Changhong; Zhu Weiguang; Yu Ting; Chen Xiaofeng; Yao Xi

    2003-04-30

    Metal-organic decomposition-derived SrZrO{sub 3} dielectric thin films were investigated using differential thermal analysis, thermogravimetric analysis, X-ray diffraction, Fourier transform infrared reflectivity spectroscopy and atomic force microscopy to study the mechanism of phase transformation and crystallinity, and were characterized by electric and dielectric properties as well. The phase transformation and crystallinity results show that the film has amorphous structure with carbonate existing when annealed at 550 deg. C; while when annealed at 600 deg. C and above, the carbonate is decomposed and those films crystallize into perovskite phase without preferred orientation. In addition, the electric properties show these films exhibit very low leakage current density and high breakdown strength. Typically, the film annealed at 600 deg. C has the lowest leakage current density of 4.2x10{sup -10} A cm{sup -2} at the field strength of 580 kV cm{sup -1} and the breakdown strength is close to 1.3 MV cm{sup -1}. Moreover, the dielectric properties show that, at room temperature, these films have their dielectric constants higher than 22.0 with very little dispersion in a frequency range from 100 Hz to 1 MHz and are nearly independent of applied dc bias.

  14. Relative humidity sensing using dye-doped polymer thin-films on metal substrates

    Science.gov (United States)

    Kumari, Madhuri; Ding, Boyang; Blaikie, Richard

    2015-12-01

    We demonstrate humidity sensors based on optical resonances sustained in sub-wavelength thick dye-doped polymer coatings on reflecting surfaces. As a result of coupling between dye molecular absorption and Fabry-Perot resonances in the air-coating-surface cavity, the absorption spectra of such thin-film structures show a strong resonant peak under certain illumination conditions. These resonances are sensitive to the structural and material properties of the thin-film, metal underlayer and ambient conditions and hence can be used for gas and vapor sensing applications. Specifically, we present our proof of principle experimental results for humidity sensing using a thin-film structure comprising Rhodamine6G-doped polyvinyl alcohol (PVA) films on silver substrates. Depending on the PVA film thickness, dye-concertation and angle of incidence, the resonant absorption peak can undergo either red-shift or blue-shift as RH level increases in the range 20% to 60%. Also, the absorption magnitude at certain wavelengths near to resonance show almost linear reduction which can be used as the sensing signal. Our simulation studies show a very good agreement with the experimental data. The spectral and temporal sensitivity of this thin-film structure is attributed to the changes in the thickness of the PVA layer which swells by absorbing water molecules

  15. Site-selective electroless nickel plating on patterned thin films of macromolecular metal complexes.

    Science.gov (United States)

    Kimura, Mutsumi; Yamagiwa, Hiroki; Asakawa, Daisuke; Noguchi, Makoto; Kurashina, Tadashi; Fukawa, Tadashi; Shirai, Hirofusa

    2010-12-01

    We demonstrate a simple route to depositing nickel layer patterns using photocross-linked polymer thin films containing palladium catalysts, which can be used as adhesive interlayers for fabrication of nickel patterns on glass and plastic substrates. Electroless nickel patterns can be obtained in three steps: (i) the pattern formation of partially quaterized poly(vinyl pyridine) by UV irradiation, (ii) the formation of macromolecular metal complex with palladium, and (iii) the nickel metallization using electroless plating bath. Metallization is site-selective and allows for a high resolution. And the resulting nickel layered structure shows good adhesion with glass and plastic substrates. The direct patterning of metallic layers onto insulating substrates indicates a great potential for fabricating micro/nano devices.

  16. Improving catchment scale water quality modelling with continuous high resolution monitoring of metals in runoff

    Science.gov (United States)

    Saari, Markus; Rossi, Pekka; Blomberg von der Geest, Kalle; Mäkinen, Ari; Postila, Heini; Marttila, Hannu

    2017-04-01

    High metal concentrations in natural waters is one of the key environmental and health problems globally. Continuous in-situ analysis of metals from runoff water is technically challenging but essential for the better understanding of processes which lead to pollutant transport. Currently, typical analytical methods for monitoring elements in liquids are off-line laboratory methods such as ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy) and ICP-MS (ICP combined with a mass spectrometer). Disadvantage of the both techniques is time consuming sample collection, preparation, and off-line analysis at laboratory conditions. Thus use of these techniques lack possibility for real-time monitoring of element transport. We combined a novel high resolution on-line metal concentration monitoring with catchment scale physical hydrological modelling in Mustijoki river in Southern Finland in order to study dynamics of processes and form a predictive warning system for leaching of metals. A novel on-line measurement technique based on micro plasma emission spectroscopy (MPES) is tested for on-line detection of selected elements (e.g. Na, Mg, Al, K, Ca, Fe, Ni, Cu, Cd and Pb) in runoff waters. The preliminary results indicate that MPES can sufficiently detect and monitor metal concentrations from river water. Water and Soil Assessment Tool (SWAT) catchment scale model was further calibrated with high resolution metal concentration data. We show that by combining high resolution monitoring and catchment scale physical based modelling, further process studies and creation of early warning systems, for example to optimization of drinking water uptake from rivers, can be achieved.

  17. Metal-Organic Framework Thin Films as Platforms for Atomic Layer Deposition of Cobalt Ions To Enable Electrocatalytic Water Oxidation.

    Science.gov (United States)

    Kung, Chung-Wei; Mondloch, Joseph E; Wang, Timothy C; Bury, Wojciech; Hoffeditz, William; Klahr, Benjamin M; Klet, Rachel C; Pellin, Michael J; Farha, Omar K; Hupp, Joseph T

    2015-12-30

    Thin films of the metal-organic framework (MOF) NU-1000 were grown on conducting glass substrates. The films uniformly cover the conducting glass substrates and are composed of free-standing sub-micrometer rods. Subsequently, atomic layer deposition (ALD) was utilized to deposit Co(2+) ions throughout the entire MOF film via self-limiting surface-mediated reaction chemistry. The Co ions bind at aqua and hydroxo sites lining the channels of NU-1000, resulting in three-dimensional arrays of separated Co ions in the MOF thin film. The Co-modified MOF thin films demonstrate promising electrocatalytic activity for water oxidation.

  18. Preparation of Al-doped ZnO films by aqueous solution process using a continuous circulation reactor

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, Masao; Fukui, Hiroshi; Hirato, Tetsuji [Graduate School of Energy, Kyoto University, Yoshida-hommachi, Sakyo-ku, Kyoto 606-8501 (Japan)

    2012-05-15

    The fabrication of Al-doped ZnO films by an aqueous solution process using a continuous circulation reactor was studied. By heating ZnO-saturated ammonia solutions containing 2-10 mM Al(NO{sub 3}){sub 3} with pH 10.7 at 90 C under ambient pressure, polycrystalline ZnO films with Al content of 1-2 at.% were deposited. The carrier concentration of ZnO films increased with increasing Al content, indicating that Al was successfully incorporated into the ZnO crystals. The Al-doped ZnO films had carrier concentrations of 10{sup 19}-10{sup 20} cm{sup -3} and mobilities of 0.7-7 cm{sup 2}/V/s after annealing at 300 C in air. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Effect of metal coordination on photocurrent response properties of a tetrathiafulvalene organogel film.

    Science.gov (United States)

    Ji, Shu-Fang; Sun, Yong-Gang; Huo, Peng; Shen, Wei-Chun; Huang, Yu-De; Zhu, Qin-Yu; Dai, Jie

    2014-04-07

    Organic low molecular weight gelators with a tetrathiafulvalene (TTF) unit have received considerable attention because the formed gels usually exhibit redox active response and conducting or semiconducting properties. However, to our knowledge, metal coordination systems have not been reported for TTF-derived gels up to date. We have designed and synthesized a series of TTF derivatives with a diamide-diamino moiety that can coordinate to specific metal ions with square coordination geometry. Gelation properties and morphologies of the films prepared by the gelators in different hydrophobic solvents are characterized. The TTF derivative with a dodecyl group shows effective gelation properties, and electrodes with the organogel films are prepared. The effect of the Ni(II) and Cu(II) coordination on the photocurrent response property of the electrodes is examined. The metal square coordination significantly increases the photocurrent response. This gel system is the first metal coordination related TTF-gel-based photoelectric material. The mechanism of the metal coordination-improved photocurrent response property is discussed based on the crystal structural analysis and theoretical calculations.

  20. Diagnostic of the self-healing of metallized polypropylene film by modeling of the broadening emission lines of aluminum emitted by plasma discharge

    Science.gov (United States)

    Tortai, J.-H.; Bonifaci, N.; Denat, A.; Trassy, C.

    2005-03-01

    Metallized-film capacitors have the property, even under high continuous voltage, to self-heal i.e., to clear a defect in the dielectric. The self-healing process is a consequence of a transient arc discharge. It has been previously shown that during the discharge, due to Joule effect, the metal is vaporized until the arc extinguishes. The discharge duration has been found to be inversely proportional to the mechanical pressure applied on the layers of metallized films making up a capacitor. The aim of this study is to understand the physical processes involved in this spontaneous extinction of the arc discharge. Emission spectroscopy has been used to provide information about the physical properties (temperatures, electronic and neutral particles densities, etc.) of the plasma induces by a self-healing. An analysis, based on the broadenings and shifts of Al atomic lines, of the experimental light spectra obtained has shown that the self-healing process leads to the generation, from the vaporized metal, of a high-density and relatively weakly ionized aluminum plasma. The plasma density increases with the pressure applied on the film layers and, consequently, the density power needed to extend the plasma zone increases as well and the arc discharge goes out faster as experimentally observed.

  1. Probing large area surface plasmon interference in thin metal films using photon scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Passian, A.; Wig, A.; Lereu, A.L.; Evans, P.G.; Meriaudeau, F.; Thundat, T.; Ferrell, T.L

    2004-08-15

    The interference of surface plasmons can provide important information regarding the surface features of the hosting thin metal film. We present an investigation of the interference of optically excited surface plasmons in the Kretschmann configuration in the visible spectrum. Large area surface plasmon interference regions are generated at several wavelengths and imaged with the photon scanning tunneling microscope. Furthermore, we discuss the non-retarded dispersion relations for the surface plasmons in the probe-metal system modeled as confocal hyperboloids of revolution in the spheroidal coordinate systems.

  2. Surface structure determinations of crystalline ionic thin films grown on transition metal single crystal surfaces by low energy electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Joel Glenn [Univ. of California, Berkeley, CA (United States)

    2000-05-01

    The surface structures of NaCl(100), LiF(100) and alpha-MgCl2(0001) adsorbed on various metal single crystals have been determined by low energy electron diffraction (LEED). Thin films of these salts were grown on metal substrates by exposing the heated metal surface to a molecular flux of salt emitted from a Knudsen cell. This method of investigating thin films of insulators (ionic salts) on a conducting substrate (metal) circumvents surface charging problems that plagued bulk studies, thereby allowing the use of electron-based techniques to characterize the surface.

  3. Plasmon hybridization in silver nanoislands as semishell arrays coupled to a thin metallic film

    DEFF Research Database (Denmark)

    Maaroof, Abbas; Nygaard, Jens Vinge; Sutherland, Duncan S

    2011-01-01

    interactions for such a nanosystem exhibits two pronounced resonances and interpret the coupling in terms of Fano resonances. The higher energy resonance is identified as a symmetric hybridization mode between localized plasmon resonances in the island semishell array and surface plasmon polaritons...... in the metal film and while the lower energy resonance is identified as a corresponding anti-symmetric hybridization mode. Increasing the size of the particle arrays enhances and red shifts the resonances. We show that adding a dielectric spacer between the semishell island array and the metal film results...... in a red shifting of the resonances and introduce an additional high energy spectral peak. The effect of the spacer layer is interpreted as a reduced hybridization and the generation of additional localized surface plasmon resonances....

  4. Effective Third-Order Nonlinearities in Metallic Refractory Titanium Nitride Thin Films

    CERN Document Server

    Kinsey, Nathaniel; Courtwright, Devon; DeVault, Clayton; Bonner, Carl E; Gavrilenko, Vladimir I; Shalaev, Vladimir M; Hagan, David J; Van Stryland, Eric W; Boltasseva, Alexandra

    2015-01-01

    Nanophotonic devices offer an unprecedented ability to concentrate light into small volumes which can greatly increase nonlinear effects. However, traditional plasmonic materials suffer from low damage thresholds and are not compatible with standard semiconductor technology. Here we study the nonlinear optical properties in the novel refractory plasmonic material titanium nitride using the Z scan method at 1550 nm and 780 nm. We compare the extracted nonlinear parameters for TiN with previous works on noble metals and note a similarly large nonlinear optical response. However, TiN films have been shown to exhibit a damage threshold up to an order of magnitude higher than gold films of a similar thickness, while also being robust, cost-efficient, bio- and CMOS compatible. Together, these properties make TiN a promising material for metal-based nonlinear optics.

  5. Strong spin-orbit fields and Dyakonov-Perel spin dephasing in supported metallic films

    Science.gov (United States)

    Long, Nguyen H.; Mavropoulos, Phivos; Bauer, David S. G.; Zimmermann, Bernd; Mokrousov, Yuriy; Blügel, Stefan

    2016-11-01

    Spin dephasing by the Dyakonov-Perel mechanism in metallic films deposited on insulating substrates is revealed, and quantitatively examined by means of density functional calculations combined with a kinetic equation. The surface-to-substrate asymmetry, probed by the metal wave functions in thin films, is found to produce strong spin-orbit fields and a fast Larmor precession, giving a dominant contribution to spin decay over the Elliott-Yafet spin relaxation up to a thickness of 70 nm. The spin dephasing is oscillatory in time with a rapid (subpicosecond) initial decay. However, parts of the Fermi surface act as spin traps, causing a persistent tail signal lasting 1000 times longer than the initial decay time. It is also found that the decay depends on the direction of the initial spin polarization, resulting in a spin-dephasing anisotropy of 200% in the examined cases.

  6. Composite materials obtained by the ion-plasma sputtering of metal compound coatings on polymer films

    Science.gov (United States)

    Khlebnikov, Nikolai; Polyakov, Evgenii; Borisov, Sergei; Barashev, Nikolai; Biramov, Emir; Maltceva, Anastasia; Vereshchagin, Artem; Khartov, Stas; Voronin, Anton

    2016-01-01

    In this article, the principle and examples composite materials obtained by deposition of metal compound coatings on polymer film substrates by the ion-plasma sputtering method are presented. A synergistic effect is to obtain the materials with structural properties of the polymer substrate and the surface properties of the metal deposited coatings. The technology of sputtering of TiN coatings of various thicknesses on polyethylene terephthalate films is discussed. The obtained composites are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and scanning tunneling microscopy (STM) is shown. The examples of application of this method, such as receiving nanocomposite track membranes and flexible transparent electrodes, are considered.

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

    Science.gov (United States)

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

    2015-10-30

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

  8. Sub-monolayer film growth of a volatile lanthanide complex on metallic surfaces

    Science.gov (United States)

    Chen, Jinjie; Edelmann, Kevin; Wulfhekel, Wulf

    2015-01-01

    Summary We deposited a volatile lanthanide complex, tris(2,2,6,6-tetramethyl-3,5-heptanedionato)terbium(III), onto metal surfaces of Cu(111), Ag(111) and Au(111) in vacuum and observed well-ordered sub-monolayer films with low temperature (5 K) scanning tunneling microscopy. The films show a distorted three-fold symmetry with a commensurate structure. Scanning tunneling spectroscopy reveals molecular orbitals delocalized on the ligands of the molecule. Our results imply that this complex can be transferred onto the metal substrates without molecular decomposition or contamination of the surface. This new rare-earth-based class of molecules broadens the choice of molecular magnets to study with scanning tunneling microscopy. PMID:26733215

  9. Sub-monolayer film growth of a volatile lanthanide complex on metallic surfaces

    Directory of Open Access Journals (Sweden)

    Hironari Isshiki

    2015-12-01

    Full Text Available We deposited a volatile lanthanide complex, tris(2,2,6,6-tetramethyl-3,5-heptanedionatoterbium(III, onto metal surfaces of Cu(111, Ag(111 and Au(111 in vacuum and observed well-ordered sub-monolayer films with low temperature (5 K scanning tunneling microscopy. The films show a distorted three-fold symmetry with a commensurate structure. Scanning tunneling spectroscopy reveals molecular orbitals delocalized on the ligands of the molecule. Our results imply that this complex can be transferred onto the metal substrates without molecular decomposition or contamination of the surface. This new rare-earth-based class of molecules broadens the choice of molecular magnets to study with scanning tunneling microscopy.

  10. Inverse analysis determining interfacial properties between metal film and ceramic substrate with an adhesive layer

    Institute of Scientific and Technical Information of China (English)

    Haifeng Zhao; Yueguang Wei

    2008-01-01

    In the present study, peel tests and inverse analysis were performed to determine the interfacial mechanical parameters for the metal film/ceramic system with an epoxy interface layer between film and ceramic. Al films with a series of thicknesses between 20 and 250μm and three peel angles of 90°,135°and 180°were considered. A finite element model with the cohesive zone elements was used to simulate the peeling process. The finite element results were taken as the training data of a neural network in the inverse analysis. The interfacial cohesive energy and the separation strength can be determined based on the inverse analysis and peel experimental result

  11. Electrical four-point probing of spherical metallic thin films coated onto micron sized polymer particles

    Energy Technology Data Exchange (ETDEWEB)

    Pettersen, Sigurd R., E-mail: sigurd.r.pettersen@ntnu.no, E-mail: jianying.he@ntnu.no; Stokkeland, August Emil; Zhang, Zhiliang; He, Jianying, E-mail: sigurd.r.pettersen@ntnu.no, E-mail: jianying.he@ntnu.no [NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Kristiansen, Helge [NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Conpart AS, Dragonveien 54, NO-2013 Skjetten (Norway); Njagi, John; Goia, Dan V. [Center for Advanced Materials Processing, Clarkson University, Potsdam, New York 13699-5814 (United States); Redford, Keith [Conpart AS, Dragonveien 54, NO-2013 Skjetten (Norway)

    2016-07-25

    Micron-sized metal-coated polymer spheres are frequently used as filler particles in conductive composites for electronic interconnects. However, the intrinsic electrical resistivity of the spherical thin films has not been attainable due to deficiency in methods that eliminate the effect of contact resistance. In this work, a four-point probing method using vacuum compatible piezo-actuated micro robots was developed to directly investigate the electric properties of individual silver-coated spheres under real-time observation in a scanning electron microscope. Poly(methyl methacrylate) spheres with a diameter of 30 μm and four different film thicknesses (270 nm, 150 nm, 100 nm, and 60 nm) were investigated. By multiplying the experimental results with geometrical correction factors obtained using finite element models, the resistivities of the thin films were estimated for the four thicknesses. These were higher than the resistivity of bulk silver.

  12. Light scattering by epitaxial VO{sub 2} films near the metal-insulator transition point

    Energy Technology Data Exchange (ETDEWEB)

    Lysenko, Sergiy, E-mail: sergiy.lysenko@upr.edu; Fernández, Felix; Rúa, Armando; Figueroa, Jose; Vargas, Kevin; Cordero, Joseph [Department of Physics, University of Puerto Rico, Mayaguez, Puerto Rico 00681 (United States); Aparicio, Joaquin [Department of Physics, University of Puerto Rico-Ponce, Ponce, Puerto Rico 00732 (United States); Sepúlveda, Nelson [Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States)

    2015-05-14

    Experimental observation of metal-insulator transition in epitaxial films of vanadium dioxide is reported. Hemispherical angle-resolved light scattering technique is applied for statistical analysis of the phase transition processes on mesoscale. It is shown that the thermal hysteresis strongly depends on spatial frequency of surface irregularities. The transformation of scattering indicatrix depends on sample morphology and is principally different for the thin films with higher internal elastic strain and for the thicker films where this strain is suppressed by introduction of misfit dislocations. The evolution of scattering indicatrix, fractal dimension, surface power spectral density, and surface autocorrelation function demonstrates distinctive behavior which elucidates the influence of structural defects and strain on thermal hysteresis, twinning of microcrystallites, and domain formation during the phase transition.

  13. Mechanism of resonant perfect optical absorption in dielectric film supporting metallic grating structures.

    Science.gov (United States)

    Chen, Xiumei; Yan, Xiaopeng; Li, Ping; Mou, Yongni; Wang, Wenqiang; Guan, Zhiqiang; Xu, Hongxing

    2016-08-22

    The mechanism of resonant perfect optical absorbers is quantitatively revealed by the coupled mode method for the air/grating/dielectric film/air four region system. The sufficient and necessary conditions of the perfect optical absorption are derived from the interface scattering coefficients analyses. The coupling of the Fabry-Perot modes in the grating slits and non-zero order quasi waveguide modes in the dielectric film play a key role for the perfect optical absorption when the light is incident from the grating side. The analytical sufficient and necessary conditions of the perfect optical absorption provide an efficient tool towards geometry design for the perfect optical absorption at the specific wavelengths. The advantages of a widely tunable perfect optical absorption wavelength, a high Q factor and the confined energy loss on metal surfaces make the air/grating/film/air structures promising for applications in sensing, modulation and detection.

  14. Highly textured oxypnictide superconducting thin films on metal substrates

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Kazumasa, E-mail: iida@nuap.nagoya-u.ac.jp; Kurth, Fritz; Grinenko, Vadim; Hänisch, Jens [Institute for Metallic Materials, IFW Dresden, D-01171 Dresden (Germany); Chihara, Masashi; Sumiya, Naoki; Hatano, Takafumi; Ikuta, Hiroshi [Department of Crystalline Materials Science, Nagoya University, Chikusa, Nagoya 464-8603 (Japan); Ichinose, Ataru; Tsukada, Ichiro [Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196 (Japan); Matias, Vladimir [iBeam Materials, Inc., 2778A Agua Fria Street, Santa Fe, New Mexico 87507 (United States); Holzapfel, Bernhard [Institute for Technical Physics, Karlsruhe Institute of Technology, Hermann von Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

    2014-10-27

    Highly textured NdFeAs(O,F) thin films have been grown on ion beam assisted deposition-MgO/Y{sub 2}O{sub 3}/Hastelloy substrates by molecular beam epitaxy. The oxypnictide coated conductors showed a superconducting transition temperature (T{sub c}) of 43 K with a self-field critical current density (J{sub c}) of 7.0×10{sup 4} A/cm{sup 2} at 5 K, more than 20 times higher than powder-in-tube processed SmFeAs(O,F) wires. Albeit higher T{sub c} as well as better crystalline quality than Co-doped BaFe{sub 2}As{sub 2} coated conductors, in-field J{sub c} of NdFeAs(O,F) was lower than that of Co-doped BaFe{sub 2}As{sub 2}. These results suggest that grain boundaries in oxypnictides reduce J{sub c} significantly compared to that in Co-doped BaFe{sub 2}As{sub 2} and, hence biaxial texture is necessary for high J{sub c.}.

  15. Fracture resistance of dental nickel–titanium rotary instruments with novel surface treatment: Thin film metallic glass coating

    Directory of Open Access Journals (Sweden)

    Chih-Wen Chi

    2017-05-01

    Conclusion: The novel surface treatment of Ti-Zr-B thin film metallic glass on dental NiTi rotary files can effectively improve the fatigue fracture resistance by offering a smooth coated surface with amorphous microstructure.

  16. Water Splitting by Thin Film Metal-Oxo Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Nocera, Daniel [Harvard Univ., Cambridge, MA (United States)

    2013-03-15

    The dropping price of silicon photovoltaics in the United States is causing load defection to solar supply at an accelerated pace. This conversion to solar and, more generally, other renewable energy sources has accordingly turned the energy research focus from generation to one of storage. Truly disruptive improvements in energy storage technologies are limited by energy density. This limitation, however, does not apply to fuels, which possess the energy density needed for large-scale energy storage. The first step of the basic science needed to drive such historic restructuring of the U.S. energy infrastructure begins with the solar-driven generation of hydrogen and oxygen from water. The solar-produced hydrogen may then be combined with carbon dioxide to deliver any number of fuels. Obviously, light does not directly act on water to engender its splitting into its elemental components. Hence, catalysts are needed to drive the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Of these two reactions, the four-electron, four-proton oxidation of OER is the more kinetically challenging reaction, and therefore the development of energy efficient solar fuels processes demands that OER be accomplished at a minimal overpotential. The research completed in this program developed catalysts that drive OER and at the same time meet the important criteria of (1) using non-critical materials that (2) are easy to assemble and (3) accomplish OER under simple conditions. Research was designed to uncover the chemical principles that underlie the self-assembly of metal oxide oxygen evolving catalysts (M-OEC) from the metals of M = Mn, Co, and Ni. For example, a dogma of heterogeneous catalysis of any sort is that “edges” matter in promoting catalytic transformations. We provided a rationale for such dogma by showing that the OER in Co-OEC occurred at a dimensionally reduced dicobalt edge site. Edge site reactivity was clearly revealed analyzing 18O labeled

  17. Quantum Electron Plasma, Visible and Ultraviolet P-wave and Thin Metallic Film

    CERN Document Server

    Yushkanov, A A

    2016-01-01

    The interaction of the visible and ultraviolet electromagnetic P-wave with the thin flat metallic film localized between two dielectric media is studied numerically in the framework of the quantum degenerate electron plasma approach. The reflectance, transmittance and absorptance power coefficients are chosen for investigation. It is shown that for the frequencies in the visible and ultraviolet ranges, the quantum power coefficients differ from the ones evaluated in framework of both the classical spatial dispersion and the Drude - Lorentz approaches.

  18. Axisymmetric modeling of ultrashort-pulse laser interactions with thin metal film

    Directory of Open Access Journals (Sweden)

    E. Majchrzak

    2011-10-01

    Full Text Available The hyperbolic two-temperature model is used in order to describe the heat propagation in metal film subjected to an ultrashort-pulse laser heating. An axisymmetric heat soureceewith Gaussian temporeal and spatial distributions has been taken into account. At the stage of numerical computations the finite difference method is used. In the final part of the paper the examples of computations are shown.

  19. Quantum electron plasma, visible and ultraviolet P-wave and thin metallic film

    Science.gov (United States)

    Yushkanov, A. A.; Zverev, N. V.

    2017-02-01

    The interaction of the visible and ultraviolet electromagnetic P-wave with the thin flat metallic film localized between two dielectric media is studied numerically in the framework of the quantum degenerate electron plasma approach. The reflectance, transmittance and absorptance power coefficients are chosen for investigation. It is shown that for the frequencies in the visible and ultraviolet ranges, the quantum power coefficients differ from the ones evaluated in framework of both the classical spatial dispersion and the Drude-Lorentz approaches.

  20. Numerical Modeling of Melting Process of Thin Metal Films Subjected to the Short Laser Pulse

    Directory of Open Access Journals (Sweden)

    E. Majchrzak

    2012-12-01

    Full Text Available Thin metal film subjected to a short-pulse laser heating is considered. The parabolic two-temperature model describing the temporal and spatial evolution of the lattice and electrons temperatures is discussed and the melting process of thin layer is taken into account. At the stage of numerical computations the finite difference method is used. In the final part of the paper the examples of computations are shown.

  1. Quantum electron plasma, visible and ultraviolet P-wave and thin metallic film

    Energy Technology Data Exchange (ETDEWEB)

    Yushkanov, A.A., E-mail: yushkanov@inbox.ru; Zverev, N.V., E-mail: zverev_nv@mail.ru

    2017-02-12

    The interaction of the visible and ultraviolet electromagnetic P-wave with the thin flat metallic film localized between two dielectric media is studied numerically in the framework of the quantum degenerate electron plasma approach. The reflectance, transmittance and absorptance power coefficients are chosen for investigation. It is shown that for the frequencies in the visible and ultraviolet ranges, the quantum power coefficients differ from the ones evaluated in framework of both the classical spatial dispersion and the Drude–Lorentz approaches.

  2. Spin-Hall conductivity and electric polarization in metallic thin films

    KAUST Repository

    Wang, Xuhui

    2013-02-21

    We predict theoretically that when a normal metallic thin film (without bulk spin-orbit coupling, such as Cu or Al) is sandwiched by two insulators, two prominent effects arise due to the interfacial spin-orbit coupling: a giant spin-Hall conductivity due to the surface scattering and a transverse electric polarization due to the spin-dependent phase shift in the spinor wave functions.

  3. Optimization of film synthesized rare earth transition metal permanent magnet systems

    Energy Technology Data Exchange (ETDEWEB)

    Cadieu, F.J.

    1992-01-01

    Progress is reported in three areas: high coercivity Sm-Fe-Ti-V, Sm-Fe-Zr, and two element Sm-Fe Sm{sub 5}(Fe,T){sub 17} type crystalline phases; ThMn{sub 12} type pseudobinary SmFe{sub 12-x}T{sub x}(0{le}{times}{le}1.5); and sputter process control for the synthesis of precisely textured rare earth-transition metal magnetic films. (DLC)

  4. Nanogroove array on thin metallic film as planar lens with tunable focusing

    OpenAIRE

    Wellems, L. David; Huang, Danhong; Leskova, T. A; Maradudin, A. A.

    2012-01-01

    Numerical results for the distributions of light transmitted through metallic planar lenses composed of symmetric nanogroove arrays on the surfaces of a gold film are presented and explained. Both the near- and far-field distributions of the intensity of light transmitted are calculated by using a Green's function formalism. Results for an optimal transverse focus based on a quadratic variation of groove width are obtained. Meanwhile, a significant dependence of the focal length on the wavele...

  5. Jet formation in spallation of metal film from substrate under action of femtosecond laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Inogamov, N. A., E-mail: nailinogamov@googlemail.com [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation); Zhakhovskii, V. V. [Dukhov All-Russia Research Institute of Automatics (Russian Federation); Khokhlov, V. A. [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation)

    2015-01-15

    It is well known that during ablation by an ultrashort laser pulse, the main contribution to ablation of the substance is determined not by evaporation, but by the thermomechanical spallation of the substance. For identical metals and pulse parameters, the type of spallation is determined by film thickness d{sub f}. An important gauge is metal heating depth d{sub T} at the two-temperature stage, at which electron temperature is higher than ion temperature. We compare cases with d{sub f} < d{sub T} (thin film) and d{sub f} ≫ d{sub T} (bulk target). Radius R{sub L} of the spot of heating by an optical laser is the next (after d{sub f}) important geometrical parameter. The morphology of film bulging in cases where d{sub f} < d{sub T} on the substrate (blistering) changes upon a change in radius R{sub L} in the range from diffraction limit R{sub L} ∼ λ to high values of R{sub L} ≫ λ, where λ ∼ 1 μm is the wavelength of optical laser radiation. When d{sub f} < d{sub T}, R{sub L} ∼ λ, and F{sub abs} > F{sub m}, gold film deposited on the glass target acquires a cupola-shaped blister with a miniature frozen nanojet in the form of a tip on the circular top of the cupola (F{sub abs} and F{sub m} are the absorbed energy and the melting threshold of the film per unit surface area of the film). A new physical mechanism leading to the formation of the nanojet is proposed.

  6. Characterization of PZT thin films on metal substrates; Charakterisierung von PZT-Duennschichten auf Metallsubstraten

    Energy Technology Data Exchange (ETDEWEB)

    Dutschke, A.

    2008-02-02

    Lead zirconate titanate (PbZr{sub x}Ti{sub 1-x}O{sub 3},PZT) is one of the most applied ceramic materials because of its distinctive piezo- and ferroelectric properties. Prepared as thin films on flexible, metallic substrates it can be used for various applications as strain gauges, key switches, vibration dampers, microactuators and ultrasonic transducers. The aim of this work is to analyze the microstructure and the phase-content of PZT-thin films deposited on temperature- und acid-resistant hastelloy-sheets, to correlate the results with the ferroelectric and dielectric properties. It is demonstrated, that the specific variation of the microstructure can be achieved by different thermal treatments and the selective addition of Neodymium as dopant. Nd-doping leads to a shift of the maximum nucleation rate towards reduced temperatures and a decrease in the rate of growth compared to undoped films. The PZT-films are prepared by a sol-gel-process in fourfold multilayers with a composition near the morphotropic phase boundary, where the tetragonal und rhombohedral perovskite-phases coexist. The crystallisation in Nd-doped and undoped films takes place heterogeneously, preferentially at the interfaces and on the surface of the multilayered films as well as on the inner surface of pores within the films. For the first time, the Zr:Ti fluctuation phenomena emerging in sol-gel derived PZT films is related to the microstructure and the local phase content on a nanometer scale. In this connection it is proved, that long-distance Zr:Ti gradients arise preferentially before and during the crystallisation of the pyrochlore phase. During the following crystallisation of the perovskite phase, the crystallites grow across these gradients without modifying them. It is pointed out that the fluctuation in the Zr:Ti ratio has only minor influence on the amount of the tetragonal or rhombohedral distortion of the crystallites after the transition from the para- to the ferroelectric

  7. Deposition of metal chalcogenide thin films by successive ionic layer adsorption and reaction (SILAR) method

    Indian Academy of Sciences (India)

    H M Pathan; C D Lokhande

    2004-04-01

    During last three decades, successive ionic layer adsorption and reaction (SILAR) method, has emerged as one of the solution methods to deposit a variety of compound materials in thin film form. The SILAR method is inexpensive, simple and convenient for large area deposition. A variety of substrates such as insulators, semiconductors, metals and temperature sensitive substrates (like polyester) can be used since the deposition is carried out at or near to room temperature. As a low temperature process, it also avoids oxidation and corrosion of the substrate. The prime requisite for obtaining good quality thin film is the optimization of preparative provisos viz. concentration of the precursors, nature of complexing agent, pH of the precursor solutions and adsorption, reaction and rinsing time durations etc. In the present review article, we have described in detail, successive ionic layer adsorption and reaction (SILAR) method of metal chalcogenide thin films. An extensive survey of thin film materials prepared during past years is made to demonstrate the versatility of SILAR method. Their preparative parameters and structural, optical, electrical properties etc are described. Theoretical background necessary for the SILAR method is also discussed.

  8. Unintentional carbide formation evidenced during high-vacuum magnetron sputtering of transition metal nitride thin films

    Science.gov (United States)

    Greczynski, G.; Mráz, S.; Hultman, L.; Schneider, J. M.

    2016-11-01

    Carbide signatures are ubiquitous in the surface analyses of industrially sputter-deposited transition metal nitride thin films grown with carbon-less source materials in typical high-vacuum systems. We use high-energy-resolution photoelectron spectroscopy to reveal details of carbon temporal chemical state evolution, from carbide formed during film growth to adventitious carbon adsorbed upon contact with air. Using in-situ grown Al capping layers that protect the as-deposited transition metal nitride surfaces from oxidation, it is shown that the carbide forms during film growth rather than as a result of post deposition atmosphere exposure. The XPS signature of carbides is masked by the presence of adventitious carbon contamination, appearing as soon as samples are exposed to atmosphere, and eventually disappears after one week-long storage in lab atmosphere. The concentration of carbon assigned to carbide species varies from 0.28 at% for ZrN sample, to 0.25 and 0.11 at% for TiN and HfN, respectively. These findings are relevant for numerous applications, as unintentionally formed impurity phases may dramatically alter catalytic activity, charge transport and mechanical properties by offsetting the onset of thermally-induced phase transitions. Therefore, the chemical state of C impurities in PVD-grown films should be carefully investigated.

  9. Electrical properties of nanoscale metallic thin films on dielectric elastomer at various strain rates

    Science.gov (United States)

    Faisal, Md. Shahnewaz Sabit; Ye, Zhihang; Chen, Zheng; Asmatulu, Ramazan

    2015-04-01

    Dielectric elastomers (DEs) have significant applications in artificial muscle and other biomedical equipment and device fabrications. Metallic thin films by thin film transfer and sputter coating techniques can provide conductive surfaces on the DE samples, and can be used as electrodes for the actuators and other biomedical sensing devices. In the present study, 3M VHB 4910 tape was used as a DE for the coating and electrical characterization tests. A 150 nm thickness of gold was coated on the DE surfaces by sputter coating under vacuum with different pre-strains, ranging from 0 to 100%. Some of the thin films were transferred to the surface of the DEs. Sputter coating, and direct transferring gold leaf coating methods were studied and the results were analyzed in detail in terms of the strain rates and electrical resistivity changes. Initial studies indicated that the metallic surfaces remain conductive even though the DE films were considerably elongated. The coated DEs can be used as artificial muscle by applying electrical stimulation through the conductive surfaces. This study may provide great benefits to the readers, researchers, as well as companies involved in manufacturing of artificial muscles and actuators using smart materials.

  10. Pulsed laser deposition of metallic films on the surface of diamond particles for diamond saw blades

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Chao [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, WuHan, Hubei 430074 (China); Luo Fei [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, WuHan, HuBei 430074 (China); Long Hua [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Hu Shaoliu [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Li Bo [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Wang Youqing [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)]. E-mail: lchwan@hust.edu.cn

    2005-06-15

    Ti or Ni films have been deposited on the diamond particle surfaces by pulsed laser deposition. Compressive resistance of the uncoated and coated diamond particles was measured, respectively, in the experiments. The compressive resistance of the Ti-coated diamonds particles was found much higher than that of the uncoated ones. It increased by 39%. The surface morphology is observed by the metallography microscope. The surface of the uncoated diamonds particles had many hollows and flaws, while the surface of Ni-coated diamond particles was flat and smooth, and the surface of Ti-coated diamond particles had some metal masses that stood out of the surface of the Ti-coated film. The components of the metallic films of diamond particles were examined by X-ray diffractometry (XRD). TiC was found formed on the Ti-coated diamond surface, which resulted in increased surface bonding strength between the diamond particles and the Ti films. Meanwhile, TiC also favored improving the bonding strength between the coated diamond particles and the binding materials. Moreover, the bending resistance of the diamond saw blade made of Ti-coated diamond was drastically higher than that of other diamond saw blades, which also played an important role in improving the blade's cutting ability and lifetime. Therefore, it was most appropriate that the diamond saw blade was made of Ti-coated diamond particles rather than other materials.

  11. Investigation of the preparation and properties of organic dye/metal oxide composite thin films

    Science.gov (United States)

    Jaeger, Steffen; Neumann, F.; Klages, Claus-Peter

    1994-11-01

    In this study the growth, structure and physical, particularly optical properties of composite thin films (copper-phthalocyanine-SiO2) with different dye contents are investigated by means of optical spectroscopy (UV-IR), electron probe micro analysis, atomic force microscopy and scanning electron microscopy measurements and compared with the properties of pure dye thin films of different thicknesses and dye/metal oxide multilayer structures, respectively. The composite thin films show spectral shifts and changes in the extension and the intensity of the typical absorption bands in the visible spectral range depending on the dye concentration in the composites. This behavior is accompanied by pronounced color changes, e.g. from blue-green to green in the CuPc-SiO2 system. The results show, that the CuPc- SiO2 composite properties are mainly influenced by the size and kind of dye aggregates in the films (monomer, dimer) and not by interaction of dye molecules with the metal oxide matrix.

  12. A simplified density functional theory method for charged adsorbates on an ultrathin, insulating film supported by a metal substrate

    OpenAIRE

    Scivetti, Ivan; Persson, Mats

    2013-01-01

    A simplified density functional theory (DFT) method for charged adsorbates on an ultrathin, insulating film supported by a metal substrate is developed and presented. This new method is based on a previous DFT development that uses a perfect conductor (PC) model to approximate the electrostatic response of the metal substrate, while the film and the adsorbate are both treated fully within DFT [I. Scivetti and M. Persson, Journal of Physics: Condensed Matter 25, 355006 (2013)]. The missing int...

  13. Frequency dispersion of the magnetic anisotropy field in metallic magnetic films with the plane anisotropy of electrical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Zimin, A.B.; Kornev, Y.V.; Sementsova, T.M.; Sidorenkov, V.V.

    1986-07-01

    Presence of the frequency dispersion of the field of induced single axis magnetic anisotropy and the angular position of the axis of easy magnetization in the film plane has been determined in metallic magnetic films with plane anisotropy of electrical conductivity. Theoretical dependences have been obtained which given satisfactory agreement with experimental data for cobalt and permalloy films prepared by sputtering on glass substrates and using the incident molecular beam under an angle with the substrate.

  14. Continuous production of carbon nanotubes and diamond films by swirled floating catalyst chemical vapour deposition method

    Directory of Open Access Journals (Sweden)

    S.E. Iyuke

    2010-01-01

    Full Text Available Various techniques for the synthesis of carbon nanotubes (CNTs are being developed to meet an increasing demand as a result of their versatile applications. Swirled floating catalyst chemical vapour deposition (SFCCVD is one of these techniques. This method was used to synthesise CNTs on a continuous basis using acetylene gas as a carbon source, ferrocene dissolved in xylene as a catalyst precursor, and both hydrogen and argon as carrier gases. Transmission electron microscopy analyses revealed that a mixture of single and multi-wall carbon nanotubes and other carbon nanomaterials were produced within the pyrolytic temperature range of 900–1 100°C and acetylene flow rate range of 118–370 ml min–1. Image comparison of raw and purified products showed that low contents of iron particles and amorphous carbon were contained in the synthesised carbon nanotubes. Diamond films were produced at high ferrocene concentration, hydrogen flow rate and pyrolysis temperatures, while carbon nanoballs were formed and attached to the surface of theCNTs at low ferrocene content and low pyrolysis temperature.

  15. STUDY ON THE VIBRATION CHARACTERISTIC OF THE METAL PUSHING BELT CONTINUOUSLY VARIABLE TRANSMISSION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The solid and finite element model of metal pushing type continuously variable transmission are established at speed ratio of i=0.5 and i=2.0.In order to solve the problem of the complicated of structure,the node-node rod discrete finite element model is put forward and the whole system is simplified and established.The natural frequency and mode shape of system are solved by iterative Lanczos-reduce method for sensitivity analysis in finite element model.The new method and the result can be used to improve the smoothness of the variable transmission system and to propose the theory for reducing noise at operation.

  16. Interlayer utilization (including metal borides) for subsequent deposition of NSD films via microwave plasma CVD on 316 and 440C stainless steels

    Science.gov (United States)

    Ballinger, Jared

    . Surface boriding was implemented using the novel method of microwave plasma CVD with a mixture of hydrogen and diborane gases. On 440C bearings, dual phase boride layers of Fe2B and FeB were formed which supported adhered nanostructured diamond films. Continuity of the films was not seamless with limited regions remaining uncoated potentially corresponding to delamination of the film as evidenced by the presence of tubular structures presumably composed of sp2 bonded carbon. Surface boriding of 316 stainless steel discs was conducted at various powers and pressures to achieve temperatures ranging from 550-800 °C. The substrate boriding temperature was found to substantially influence the resultant interlayer by altering the metal boride(s) present. The lowest temperatures produced an interlayer where CrB was the single detected phase, higher temperatures yielded the presence of only Fe2B, and a combination of the two phases resulted from an intermediate boriding temperature. Compared with the more common, commercialized boriding methods, this a profound result given the problems posed by the FeB phase in addition to other advantages offered by CVD processes and microwave generated plasmas in general. Indentation testing of the boride layers revealed excellent adhesion strength for all borided interlayers, and above all, no evidence of cracking was observed for a sole Fe2B phase. As with boriding of 440C bearings, subsequent diamond deposition was achieved on these interlayers with substantially improved adhesion strength relative to diamond coated TiN interlayers. Both XRD and Raman spectroscopy confirmed a nanostructured diamond film with interfacial chromium carbides responsible for enhanced adhesion strength. Interlayers consisting solely of Fe2B have displayed an ability to support fully continuous nanostructured diamond films, yet additional study is required for consistent reproduction. This is in good agreement with initial work on pack borided high alloy steels

  17. The influence of metal interlayers on the structural and optical properties of nano-crystalline TiO 2 films

    KAUST Repository

    Yang, Yong

    2012-03-01

    TiO 2-M-TiO 2 (M = W, Co and Ag) multilayer films have been deposited on glass substrates using reactive magnetron sputtering, then annealed in air for 2 h at 500°C. The structure, surface morphology and optical properties of the films have been studied using X-ray diffraction, Raman spectroscopy, atomic force microscopy and UV-vis spectroscopy. The TiO 2-W-TiO 2 and TiO 2-Co-TiO 2 films showed crystalline phases, whereas the TiO 2-Ag-TiO 2 films remained in the amorphous state. The crystallization temperature for the TiO 2-M-TiO 2 films decreased significantly compared with pure TiO 2 film deposited on quartz. Detailed analysis of the Raman spectra suggested that the crystallization of TiO 2-M-TiO 2 films was associated with the large structural deformation imposed by the oxidation of intermediate metal layers. Moreover, the optical band gap of the films narrowed due to the appearance of impurity levels as the metal ions migrated into the TiO 2 matrix. These results indicate that the insertion of intermediate metal layers provides a feasible access to improve the structural and optical properties of anatase TiO 2 films, leading to promising applications in the field of photocatalysis. © 2011 Elsevier B.V. All rights reserved.

  18. Partial Control of a Continuous Bioreactor: Application to an Anaerobic System for Heavy Metal Removal

    Directory of Open Access Journals (Sweden)

    M. I. Neria-González

    2016-01-01

    Full Text Available This work presents a control strategy for a continuous bioreactor for heavy metal removal. For this aim, regulation of the sulfate concentration, which is considered the measured and controlled state variable, allowed diminishing the cadmium concentration in the bioreactor, where the corresponding controller was designed via nonlinear bounded function. Furthermore, a nonlinear controllability analysis was done, which proved the closed-loop instability of the inner or uncontrolled dynamics of the bioreactor. A mathematical model, experimentally corroborated for cadmium removal, was employed as a benchmark for the proposed controller. Numerical experiments clearly illustrated the successful implementation of this methodology; therefore, cadmium removal amounted to more than 99%, when the initial cadmium concentration was up to 170 mg/L in continuous operating mode.

  19. AFM Study on Interface of HTHP As-grown Diamond Single Crystal and Metallic Film

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The study for the interface of as-grown diamond and metallic film surrounding diamond is an attractive way for understanding diamond growth mechanism at high temperature and high pressure (HTHP), because it is that through the interface carbon atom groups from the molten film are transported to growing diamond surface. It is of great interest to perform atomic force microscopy (AFM) experiment, which provides a unique technique different from that of normal optical and electron microscopy studies, to observe the interface morphology. In the present paper,we report first that the morphologies obtained by AFM on the film are similar to those of corresponding diamond surface, and they are the remaining traces after the carbon groups moving from the film to growing diamond. The fine particles and a terrace structure with homogeneous average step height are respectively found on the diamond (100) and (111) surface. Diamond growth conditions show that its growth rates and the temperature gradients in the boundary layer of the molten film at HTHP result in the differences of surface morphologies on diamond planes,being rough on (100) plane and even on the (111) plane. The diamond growth on the (100) surface at HPHT could be considered as a process of unification of these diamond fine particles or of carbon atom groups recombination on the growing diamond crystal surface. Successive growth layer steps directly suggest the layer growth mechanism of the diamond (111) plane. The sources of the layer steps might be two-dimensional nuclei and dislocations.

  20. Growth of HT-LiCoO2 thin films on Pt-metalized silicon substrates

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yao; CHUNG Chiyuen; ZHU Min

    2008-01-01

    Layered LiCoO2 (HT-LiCoO2) films were grown on Pt-metalized silicon (PMS) substrates and polished bulk nickel (PBN) substrates by pulsed laser deposition. The effects of substrate temperature, oxygen pressure, and substrate surface roughness on the microstructure of LiCoO2 films were investigated. It has been found that a higher substrate temperature and a higher oxygen pressure favor the formation of better crystallized and less lithium-deficient HT-LiCoO2 films. The HT-LiCoO2 film deposited on PBN substrates consists of large randomly orientated equiaxial grains, whereas on PMS substrate, it is made up of loosely packed highly [001] preferential orientated triangular shaped grains with the average grain size less than 100nm. Electrochemical measurements show that the highly [001] preferentially orientated nanostructured HT-LiCoO2 thin film grown on PMS substrate has good structural stability upon lithium insertion/extraction and can deliver an initial discharge capacity of approximately 45 μA·h·cm-2μm-1 with a cycling efficiency of above 99% at the charge/discharge rate of 0.5C.

  1. Electrosprayed Metal Oxide Semiconductor Films for Sensitive and Selective Detection of Hydrogen Sulfide

    Science.gov (United States)

    Ghimbeu, Camelia Matei; Lumbreras, Martine; Schoonman, Joop; Siadat, Maryam

    2009-01-01

    Semiconductor metal oxide films of copper-doped tin oxide (Cu-SnO2), tungsten oxide (WO3) and indium oxide (In2O3) were deposited on a platinum coated alumina substrate employing the electrostatic spray deposition technique (ESD). The morphology studied with scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows porous homogeneous films comprising uniformly distributed aggregates of nano particles. The X-ray diffraction technique (XRD) proves the formation of crystalline phases with no impurities. Besides, the Raman cartographies provided information about the structural homogeneity. Some of the films are highly sensitive to low concentrations of H2S (10 ppm) at low operating temperatures (100 and 200 °C) and the best response in terms of Rair/Rgas is given by Cu-SnO2 films (2500) followed by WO3 (1200) and In2O3 (75). Moreover, all the films exhibit no cross-sensitivity to other reducing (SO2) or oxidizing (NO2) gases. PMID:22291557

  2. Laser-induced spalling of thin metal film from silica substrate followed by inflation of microbump

    Science.gov (United States)

    Inogamov, N. A.; Zhakhovsky, V. V.; Migdal, K. P.

    2016-04-01

    Dynamics of a thin gold film on a silica substrate triggered by fast heating with the use of a subpicosecond laser pulse is studied. The pressure waves generated by such heating may result in spalling (delamination) of the film and its flying away from the substrate after an acoustic time defined by the film thickness and speed of sound in metal. Intensity of the heating laser beam has the spatial Gaussian distribution in a cross section. Therefore, the heating of film surface is non-uniform along cylindrical radius measured from the beam axis. As a result of such heating, the velocity distribution in material flying away from the substrate has a maximum at the beam axis. Thus, the separated film has dome-like shape which inflates with time. Volume of an empty cavity between the separated film and the substrate increases during inflation. Typical flight velocities are in the range of 30-200 m/s. The inflation stage can last from few to several tens of nanoseconds if the diffraction-limited micron-sized laser focal spots are used. Capillary forces acting along the warped flying film decelerate the inflation of dome. Capillary deceleration of a bulging dome focuses mass flow along the dome shell in the direction of its axis. This results in formation of an axial jet and droplet in a tip of the dome. Our new simulation results and comparisons with experiments are presented. The results explain appearance of debris in a form of frozen droplets on a surface of an irradiated spot. This is the consequence of the capillary return of a droplet.

  3. Thermalization time of thin metal film heated by short pulse laser

    Institute of Scientific and Technical Information of China (English)

    Xu Hong-Yu; Zhang Yuan-Chong; Song Ya-Qin; Chen Dian-Yun

    2004-01-01

    Based on the hyperbolic two-step heat conduction model, using the Laplace transform and numerical inverse transform method (Riemann-sum approximation method), the thermal behaviour of thin metal films has been studied during femtosecond pulse laser heating. Also the thermalization time, which is the time for the electron gas and solid lattice to reach thermal balance, has been studied in detail. The values of thermalization time for silver (Ag), gold (Au),copper (Cu) and lead (Pb) are obtained. The effects of material parameters of the thin metal film on the thermalization time are considered for the four kinds of metals by changing one of the parameters and regarding the other parameters as constant. For a typical metal material, the order of the thermalization time is of the order of hundreds of picoseconds.The thermalization time decays exponentially with the increase of phonon-electron coupling factor or electron gas thermal conductivity, and it increases linearly with the increase of the ratio of lattice heat capacity to electron gas heat capacity. However, the relaxation time of the electron gas has very little effect on the thermalization time.

  4. Thermalization time of thin metal film heated by short pulse laser

    Science.gov (United States)

    Xu, Hong-Yu; Zhang, Yuan-Chong; Song, Ya-Qin; Chen, Dian-Yun

    2004-10-01

    Based on the hyperbolic two-step heat conduction model, using the Laplace transform and numerical inverse transform method (Riemann-sum approximation method), the thermal behaviour of thin metal films has been studied during femtosecond pulse laser heating. Also the thermalization time, which is the time for the electron gas and solid lattice to reach thermal balance, has been studied in detail. The values of thermalization time for silver (Ag), gold (Au), copper (Cu) and lead (Pb) are obtained. The effects of material parameters of the thin metal film on the thermalization time are considered for the four kinds of metals by changing one of the parameters and regarding the other parameters as constant. For a typical metal material, the order of the thermalization time is of the order of hundreds of picoseconds. The thermalization time decays exponentially with the increase of phonon-electron coupling factor or electron gas thermal conductivity and it increases linearly with the increase of the ratio of lattice heat capacity to electron gas heat capacity. However, the relaxation time of the electron gas has very little effect on the thermalization time.

  5. Foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for lithium-sulfur batteries

    Science.gov (United States)

    Mao, Yiyin; Li, Gaoran; Guo, Yi; Li, Zhoupeng; Liang, Chengdu; Peng, Xinsheng; Lin, Zhan

    2017-03-01

    Lithium-sulfur batteries are promising technologies for powering flexible devices due to their high energy density, low cost and environmental friendliness, when the insulating nature, shuttle effect and volume expansion of sulfur electrodes are well addressed. Here, we report a strategy of using foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for binder-free advanced lithium-sulfur batteries through a facile confinement conversion. The carbon nanotubes interpenetrate through the metal-organic frameworks crystal and interweave the electrode into a stratified structure to provide both conductivity and structural integrity, while the highly porous metal-organic frameworks endow the electrode with strong sulfur confinement to achieve good cyclability. These hierarchical porous interpenetrated three-dimensional conductive networks with well confined S8 lead to high sulfur loading and utilization, as well as high volumetric energy density.

  6. Foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for lithium-sulfur batteries.

    Science.gov (United States)

    Mao, Yiyin; Li, Gaoran; Guo, Yi; Li, Zhoupeng; Liang, Chengdu; Peng, Xinsheng; Lin, Zhan

    2017-03-06

    Lithium-sulfur batteries are promising technologies for powering flexible devices due to their high energy density, low cost and environmental friendliness, when the insulating nature, shuttle effect and volume expansion of sulfur electrodes are well addressed. Here, we report a strategy of using foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for binder-free advanced lithium-sulfur batteries through a facile confinement conversion. The carbon nanotubes interpenetrate through the metal-organic frameworks crystal and interweave the electrode into a stratified structure to provide both conductivity and structural integrity, while the highly porous metal-organic frameworks endow the electrode with strong sulfur confinement to achieve good cyclability. These hierarchical porous interpenetrated three-dimensional conductive networks with well confined S8 lead to high sulfur loading and utilization, as well as high volumetric energy density.

  7. Foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for lithium–sulfur batteries

    Science.gov (United States)

    Mao, Yiyin; Li, Gaoran; Guo, Yi; Li, Zhoupeng; Liang, Chengdu; Peng, Xinsheng; Lin, Zhan

    2017-01-01

    Lithium–sulfur batteries are promising technologies for powering flexible devices due to their high energy density, low cost and environmental friendliness, when the insulating nature, shuttle effect and volume expansion of sulfur electrodes are well addressed. Here, we report a strategy of using foldable interpenetrated metal-organic frameworks/carbon nanotubes thin film for binder-free advanced lithium–sulfur batteries through a facile confinement conversion. The carbon nanotubes interpenetrate through the metal-organic frameworks crystal and interweave the electrode into a stratified structure to provide both conductivity and structural integrity, while the highly porous metal-organic frameworks endow the electrode with strong sulfur confinement to achieve good cyclability. These hierarchical porous interpenetrated three-dimensional conductive networks with well confined S8 lead to high sulfur loading and utilization, as well as high volumetric energy density. PMID:28262801

  8. Photoluminescence response of colloidal quantum dots on VO2 film across metal to insulator transition.

    Science.gov (United States)

    Kuznetsov, Sergey N; Cheremisin, Alexander B; Stefanovich, Genrikh B

    2014-01-01

    We have proposed a method to probe metal to insulator transition in VO2 measuring photoluminescence response of colloidal quantum dots deposited on the VO2 film. In addition to linear luminescence intensity decrease with temperature that is well known for quantum dots, temperature ranges with enhanced photoluminescence changes have been found during phase transition in the oxide. Corresponding temperature derived from luminescence dependence on temperature closely correlates with that from resistance measurement during heating. The supporting reflectance data point out that photoluminescence response mimics a reflectance change in VO2 across metal to insulator transition. Time-resolved photoluminescence study did not reveal any significant change of luminescence lifetime of deposited quantum dots under metal to insulator transition. It is a strong argument in favor of the proposed explanation based on the reflectance data. 71.30. + h; 73.21.La; 78.47.jd.

  9. Thermal analysis of double-layer metal films during femtosecond laser heating

    Science.gov (United States)

    Chen, A. M.; Jiang, Y. F.; Sui, L. Z.; Liu, H.; Jin, M. X.; Ding, D. J.

    2011-05-01

    In this paper, the primary interest is the heat effect of the bottom-layer metal on the temperature distribution of the top-layer metal in a double-layer metal structure during femtosecond laser irradiation. The evolution of the surface electron and lattice temperature depends a lot on the thermal parameters of the substrate. The damage threshold can be increased by using a substrate material with high electron-lattice coupling factor. Next, we choose chrome as the bottom-layer material. The results of modeling show that the surface lattice temperature of top-layer gold can be reduced remarkably. For a fixed entire thickness of the double-layer film, there is an optimal proportion of top and bottom layers for which the damage threshold is the highest possible. Also, for increasing the damage threshold, a substrate with higher melting temperature should be chosen.

  10. MHD Stability Analysis and Flow Controls of Liquid Metal Free Surface Film Flows as Fusion Reactor PFCs

    Science.gov (United States)

    Zhang, Xiujie; Pan, Chuanjie; Xu, Zengyu

    2016-12-01

    Numerical and experimental investigation results on the magnetohydrodynamics (MHD) film flows along flat and curved bottom surfaces are summarized in this study. A simplified modeling has been developed to study the liquid metal MHD film state, which has been validated by the existing experimental results. Numerical results on how the inlet velocity (V), the chute width (W) and the inlet film thickness (d0) affect the MHD film flow state are obtained. MHD stability analysis results are also provided in this study. The results show that strong magnetic fields make the stable V decrease several times compared to the case with no magnetic field, especially small radial magnetic fields (Bn) will have a significant impact on the MHD film flow state. Based on the above numerical and MHD stability analysis results flow control methods are proposed for flat and curved MHD film flows. For curved film flow we firstly proposed a new multi-layers MHD film flow system with a solid metal mesh to get the stable MHD film flows along the curved bottom surface. Experiments on flat and curved MHD film flows are also carried out and some firstly observed results are achieved. supported by the National Magnetic Confinement Fusion Science Program of China (Nos. 2014GB125003 and 2013GB114002), National Natural Science Foundation of China (No. 11105044)

  11. High strain rate sensitivity of hardness in quinary Ti-Zr-Hf-Cu-Ni high entropy metallic glass thin films

    Science.gov (United States)

    Zhao, Shaofan; Wang, Haibin; Xiao, Lin; Guo, Nan; Zhao, Delin; Yao, Kefu; Chen, Na

    2017-10-01

    Quinary Ti-Zr-Hf-Cu-Ni high-entropy metallic glass thin films were produced by magnetron sputter deposition. Nanoindentation tests indicate that the deposited film exhibits a relatively large hardness of 10.4±0.6 GPa and a high elastic modulus of 131±11 GPa under the strain rate of 0.5 s-1. Specifically, the strain rate sensitivity of hardness measured for the thin film is 0.05, the highest value reported for metallic glasses so far. Such high strain rate sensitivity of hardness is likely due to the high-entropy effect which stabilizes the amorphous structure with enhanced homogeneity.

  12. Influence of the chemical composition and the surface structure imperfection of metal substrates on the zeolite film formation

    Energy Technology Data Exchange (ETDEWEB)

    Valtchev, V.; Mintova, S. [Institute of Applied Mineralogy, Sofia (Bulgaria)

    1995-12-01

    There are several attractive features of zeolites that make-them useful in designing molecular thin films, coatings and membranes. Metal supports axe especially convenient for zeolite containing composite materials due to their high thermal stability, acid resistance and the possibility to form micropore modules of an arbitrary shape. There axe, however, no systematic studies on the effect of the substrate chemical composition and surface structure imperfections on the zeolite film formation. This study is concerned with: (1) the effect of the metal substrate and surface imperfections on the process of film formation; (2) the effect of the surface pretreatment.

  13. Non-conductive ferromagnetic carbon-coated (Co, Ni) metal/polystyrene nanocomposites films

    Science.gov (United States)

    Takacs, H.; Viala, B.; Tortai, J.-H.; Hermán, V.; Duclairoir, F.

    2016-03-01

    This article reports non-conductive ferromagnetic properties of metal/polymer nanocomposite films intended to be used for RF applications. The nanocomposite arrangement is unique showing a core double-shell structure of metal-carbon-polystyrene: M/C//P1/P2, where M = Co, Ni is the core material, C = graphene or carbon is the first shell acting as a protective layer against oxidation, P1 = pyrene-terminated polystyrene is the second shell for electrical insulation, and P2 = polystyrene is a supporting matrix (// indicates actual grafting). The nanocomposite formulation is briefly described, and the film deposition by spin-coating is detailed. Original spin-curves are reported and analyzed. One key outcome is the achievement of uniform and cohesive films at the wafer scale. Structural properties of films are thoroughly detailed, and weight and volume fractions of M/C are considered. Then, a comprehensive overview of DC magnetic and electrical properties is reported. A discussion follows on the magnetic softness of the nanocomposites vs. that of a single particle (theoretical) and the raw powder (experimental). Finally, unprecedented achievement of high magnetization (˜0.6 T) and ultra-high resistivity (˜1010 μΩ cm) is shown. High magnetization comes from the preservation of the existing protective shell C, with no significant degradation on the particle net-moment, and high electrical insulation is ensured by adequate grafting of the secondary shell P1. To conclude, the metal/polymer nanocomposites are situated in the landscape of soft ferromagnetic materials for RF applications (i.e., inductors and antennas), by means of two phase-diagrams, where they play a crucial role.

  14. The effect of illumination on the formation of metal halide perovskite films

    Science.gov (United States)

    Ummadisingu, Amita; Steier, Ludmilla; Seo, Ji-Youn; Matsui, Taisuke; Abate, Antonio; Tress, Wolfgang; Grätzel, Michael

    2017-04-01

    Optimizing the morphology of metal halide perovskite films is an important way to improve the performance of solar cells when these materials are used as light harvesters, because film homogeneity is correlated with photovoltaic performance. Many device architectures and processing techniques have been explored with the aim of achieving high-performance devices, including single-step deposition, sequential deposition and anti-solvent methods. Earlier studies have looked at the influence of reaction conditions on film quality, such as the concentration of the reactants and the reaction temperature. However, the precise mechanism of the reaction and the main factors that govern it are poorly understood. The consequent lack of control is the main reason for the large variability observed in perovskite morphology and the related solar-cell performance. Here we show that light has a strong influence on the rate of perovskite formation and on film morphology in both of the main deposition methods currently used: sequential deposition and the anti-solvent method. We study the reaction of a metal halide (lead iodide) with an organic compound (methylammonium iodide) using confocal laser scanning fluorescence microscopy and scanning electron microscopy. The lead iodide crystallizes before the intercalation of methylammonium iodide commences, producing the methylammonium lead iodide perovskite. We find that the formation of perovskite via such a sequential deposition is much accelerated by light. The influence of light on morphology is reflected in a doubling of solar-cell efficiency. Conversely, using the anti-solvent method to form methyl ammonium lead iodide perovskite in a single step from the same starting materials, we find that the best photovoltaic performance is obtained when films are produced in the dark. The discovery of light-activated crystallization not only identifies a previously unknown source of variability in opto-electronic properties, but also opens up

  15. Performance and Stress Analysis of Metal Oxide Films for CMOS-Integrated Gas Sensors

    Directory of Open Access Journals (Sweden)

    Lado Filipovic

    2015-03-01

    Full Text Available The integration of gas sensor components into smart phones, tablets and wrist watches will revolutionize the environmental health and safety industry by providing individuals the ability to detect harmful chemicals and pollutants in the environment using always-on hand-held or wearable devices. Metal oxide gas sensors rely on changes in their electrical conductance due to the interaction of the oxide with a surrounding gas. These sensors have been extensively studied in the hopes that they will provide full gas sensing functionality with CMOS integrability. The performance of several metal oxide materials, such as tin oxide (SnO2, zinc oxide (ZnO, indium oxide (In2O3 and indium-tin-oxide (ITO, are studied for the detection of various harmful or toxic cases. Due to the need for these films to be heated to temperatures between 250°C and 550°C during operation in order to increase their sensing functionality, a considerable degradation of the film can result. The stress generation during thin film deposition and the thermo-mechanical stress that arises during post-deposition cooling is analyzed through simulations. A tin oxide thin film is deposited using the efficient and economical spray pyrolysis technique, which involves three steps: the atomization of the precursor solution, the transport of the aerosol droplets towards the wafer and the decomposition of the precursor at or near the substrate resulting in film growth. The details of this technique and a simulation methodology are presented. The dependence of the deposition technique on the sensor performance is also discussed.

  16. Performance and stress analysis of metal oxide films for CMOS-integrated gas sensors.

    Science.gov (United States)

    Filipovic, Lado; Selberherr, Siegfried

    2015-03-25

    The integration of gas sensor components into smart phones, tablets and wrist watches will revolutionize the environmental health and safety industry by providing individuals the ability to detect harmful chemicals and pollutants in the environment using always-on hand-held or wearable devices. Metal oxide gas sensors rely on changes in their electrical conductance due to the interaction of the oxide with a surrounding gas. These sensors have been extensively studied in the hopes that they will provide full gas sensing functionality with CMOS integrability. The performance of several metal oxide materials, such as tin oxide (SnO2), zinc oxide (ZnO), indium oxide (In2O3) and indium-tin-oxide (ITO), are studied for the detection of various harmful or toxic cases. Due to the need for these films to be heated to temperatures between 250°C and 550°C during operation in order to increase their sensing functionality, a considerable degradation of the film can result. The stress generation during thin film deposition and the thermo-mechanical stress that arises during post-deposition cooling is analyzed through simulations. A tin oxide thin film is deposited using the efficient and economical spray pyrolysis technique, which involves three steps: the atomization of the precursor solution, the transport of the aerosol droplets towards the wafer and the decomposition of the precursor at or near the substrate resulting in film growth. The details of this technique and a simulation methodology are presented. The dependence of the deposition technique on the sensor performance is also discussed.

  17. Morphology and Optical Properties of Zinc Oxide Films Grown on Metal Coated Glass Substrates by Aqueous Chemical Growth

    Science.gov (United States)

    Bakar, M. A.; Hamid, M. A. A.; Jalar, A.; Shamsudin, R.

    2013-04-01

    Zinc oxide films were deposited on three different metal coated substrates (gold, nickel and platinum) by aqueous chemical growth method. This paper discusses the effect of metal coated substrates on the morphology and optical properties of grown ZnO films. X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and UV-visible spectroscopy (UV-vis) were employed to characterize the samples. All the as-deposited ZnO films exhibit crystalline hexagonal wurzite structure. The crystallite size of the ZnO films were in the range of 29 to 32 nm. FESEM micrographs revealed hexagonal rod, oval-like and flower-like ZnO structures formed on all metal coated substrates. The Pt coated film contains higher density hexagonal rod as compared to others metal coated substrate. Most probably the Pt lattice parameter is the nearest to ZnO compared to nickel and gold. The optical band gap energy, Eg of ZnO films were estimated to be 3.30 eV which is near to bulk Eg, 3.37 eV. This indicates that the ZnO grown by aqueous chemical growth is able to produce similar quality properties to other conventional method either films or bulk size.

  18. Effect of metal-ion doping on the optical properties of nanocrystalline ZnO thin films

    Science.gov (United States)

    Mendoza-Galván, A.; Trejo-Cruz, C.; Lee, J.; Bhattacharyya, D.; Metson, J.; Evans, P. J.; Pal, U.

    2006-01-01

    Optical properties of metal (Al, Ag, Sb, and Sn)-ion-implanted ZnO films have been studied by ultraviolet-visible spectroscopy and spectroscopic ellipsometric techniques. The effects of metal-ion doping on the optical band gap (Eg), refractive index (n), and extinction coefficient (k) of nanocrystalline ZnO films have been studied for the similar implantation dose of all the metal ions. The ellipsometric spectra of the ion-implanted samples could be well described by considering an air/roughness/ZnO-M (layer 1)/ZnO (layer 2)/glass model. The band gap of ZnO films increases with Al ion doping and decreases with doping of Ag, Sb, and Sn ions. The refractive index of ZnO films in the visible spectral region increases substantially on Sb and Sn ion doping, while it decreases to some extent with Al ion doping.

  19. Controllability of self-aligned four-terminal planar embedded metal double-gate low-temperature polycrystalline-silicon thin-film transistors on a glass substrate

    Science.gov (United States)

    Ohsawa, Hiroki; Sasaki, Shun; Hara, Akito

    2016-03-01

    Self-aligned four-terminal n-channel (n-ch) and p-channel (p-ch) planar embedded metal double-gate polycrystalline-silicon (poly-Si) thin-film transistors (TFTs) were fabricated on a glass substrate at a low temperature of 550 °C. This device includes a metal top gate (TG) and a metal bottom gate (BG), which are used as the drive and control gates or vice versa. The BG was embedded in a glass substrate, and a poly-Si channel with large lateral grains was fabricated by continuous-wave laser lateral crystallization. The threshold voltage modulation factors under various control gate voltages (γ = ΔVth/ΔVCG) were nearly equal to the theoretical predictions in both the n- and p-ch TFTs. By exploiting this high controllability, an enhancement depletion (ED) inverter was fabricated, and successful operation at 2.0 V was confirmed.

  20. Fabrication of highly transparent Al-ion-implanted ZnO thin films by metal vapor vacuum arc method

    Science.gov (United States)

    Lee, Han; Sivashanmugan, Kundan; Kao, Chi-Yuan; Liao, Jiunn-Der

    2017-03-01

    In this study, we utilized the metal vapor vacuum arc technique to implant vaporized aluminum (Al) ions in zinc oxide (ZnO) thin films. By adjusting the ion implantation dose and operational parameters, the conductivity and optical properties of the ZnO thin film can be controlled. The electrical sheet resistance of Al-ion-implanted ZnO decreased from 3.02 × 107 to 3.03 × 104 Ω/sq, while the transparency of the film was mostly preserved (91.5% at a wavelength of 550 nm). The ZnO thin-film Young’s modulus significantly increased with increasing Al ion dose.

  1. Tilting of carbon encapsulated metallic nanocolumns in carbon-nickel nanocomposite films by ion beam assisted deposition

    Energy Technology Data Exchange (ETDEWEB)

    Krause, Matthias [Helmholtz-Zentrum Dresden-Rossendorf, PF-510119, 01314 Dresden (Germany); Technische Universitaet Dresden, D-01062 Dresden (Germany); Muecklich, Arndt; Zschornak, Matthias; Wintz, Sebastian; Gemming, Sibylle; Abrasonis, Gintautas [Helmholtz-Zentrum Dresden-Rossendorf, PF-510119, 01314 Dresden (Germany); Oates, Thomas W. H. [Leibniz-Institut fuer Analytische Wissenschaft, ISAS e.V., Albert-Einstein-Str. 9, 12489 Berlin (Germany); Luis Endrino, Jose [Surfaces and Coatings Department, Instituto de Ciencia de Materiales de Madrid, c/Sor Juana Ines de la Cruz 3, Cantoblanco, 28049 Madrid (Spain); Baehtz, Carsten; Shalimov, Artem [Helmholtz-Zentrum Dresden-Rossendorf, PF-510119, 01314 Dresden (Germany); Rossendorf Beamline, European Synchrotron Radiation Facility, F-38043 Grenoble (France)

    2012-07-30

    The influence of assisting low-energy ({approx}50-100 eV) ion irradiation effects on the morphology of C:Ni ({approx}15 at. %) nanocomposite films during ion beam assisted deposition (IBAD) is investigated. It is shown that IBAD promotes the columnar growth of carbon encapsulated metallic nanoparticles. The momentum transfer from assisting ions results in tilting of the columns in relation to the growing film surface. Complex secondary structures are obtained, in which a significant part of the columns grows under local epitaxy via the junction of sequentially deposited thin film fractions. The influence of such anisotropic film morphology on the optical properties is highlighted.

  2. Modeling of stored charge in metallized biaxially oriented polypropylene film capacitors based on charging current measurement

    Science.gov (United States)

    Li, Hua; Wang, Bowen; Li, Zhiwei; Liu, De; Lin, Fuchang; Dai, Ling; Zhang, Qin; Chen, Yaohong

    2013-10-01

    Metallized biaxially oriented polypropylene film (BOPP) capacitors are widely used in pulsed power systems. When the capacitor is used as the energy storage equipment under high electric field, more charges should be provided to maintain the voltage of the capacitor. This should be ascribed to the completion of the slow polarization which may take several hours or even longer. This paper focuses on the stored charge in metallized BOPP film capacitors. The modeling of the stored charge by the equivalent conversion of circuits is conducted to analyse the slow polarization in the BOPP film. The 3-RC network is proposed to represent the time-dependent charge stored in the capacitor. A charging current measurement system is established to investigate the charge storage property of the capacitor. The measurement system can measure the long time charging current with a sampling rate of 300Hz. The total charge calculated by the charging current indicates that the stored charge in the capacitor under the electric field of 400 V/μm is 13.5% larger than the product of the voltage and the capacitance measured by the AC bridge. The nonlinear effect of the electric field on the slow polarization charge is also demonstrated. And the simulation of charge storage based on the 3-RC network can match well with the trend of the stored charge increasing with the time.

  3. Highly Conductive, Transparent Flexible Films Based on Metal Nanoparticle-Carbon Nanotube Composites

    Directory of Open Access Journals (Sweden)

    Wen-Yin Ko

    2013-01-01

    Full Text Available Metallic nanoparticles decorated on MWCNTs based transparent conducting thin films (TCFs show a cheap and efficient option for the applications in touch screens and the replacement of the ITO film because of their interesting properties of electrical conductivity, mechanical property, chemical inertness, and other unique properties, which may not be accessible by their individual components. However, a great challenge that always remains is to develop effective ways to prepare junctions between metallic nanoparticles and MWCNTs for the improvement of high-energy barriers, high contact resistances, and weak interactions which could lead to the formation of poor conducting pathways and result in the CNT-based devices with low mechanical flexibility. Herein, we not only discuss recent progress in the preparation of MNP-CNT flexible TCFs but also describe our research studies in the relevant areas. Our result demonstrated that the MNP-CNT flexible TCFs we prepared could achieve a highly electrical conductivity with the sheet resistance of ~100 ohm/sq with ~80% transmittance at 550 nm even after being bent 500 times. This electrical conductivity is much superior to the performances of other MWCNT-based transparent flexible films, making it favorable for next-generation flexible touch screens and optoelectronic devices.

  4. Nanocomposite metal/plasma polymer films prepared by means of gas aggregation cluster source

    Energy Technology Data Exchange (ETDEWEB)

    Polonskyi, O.; Solar, P.; Kylian, O.; Drabik, M.; Artemenko, A.; Kousal, J.; Hanus, J.; Pesicka, J.; Matolinova, I. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Kolibalova, E. [Tescan, Libusina trida 21, 632 00 Brno (Czech Republic); Slavinska, D. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Biederman, H., E-mail: bieder@kmf.troja.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic)

    2012-04-02

    Nanocomposite metal/plasma polymer films have been prepared by simultaneous plasma polymerization using a mixture of Ar/n-hexane and metal cluster beams. A simple compact cluster gas aggregation source is described and characterized with emphasis on the determination of the amount of charged clusters and their size distribution. It is shown that the fraction of neutral, positively and negatively charged nanoclusters leaving the gas aggregation source is largely influenced by used operational conditions. In addition, it is demonstrated that a large portion of Ag clusters is positively charged, especially when higher currents are used for their production. Deposition of nanocomposite Ag/C:H plasma polymer films is described in detail by means of cluster gas aggregation source. Basic characterization of the films is performed using transmission electron microscopy, ultraviolet-visible and Fourier-transform infrared spectroscopies. It is shown that the morphology, structure and optical properties of such prepared nanocomposites differ significantly from the ones fabricated by means of magnetron sputtering of Ag target in Ar/n-hexane mixture.

  5. Ultrathin magnesia films as support for molecules and metal clusters: Tuning reactivity by thickness and composition

    Energy Technology Data Exchange (ETDEWEB)

    Vaida, Mihai E.; Bernhardt, Thorsten M. [Institute of Surface Chemistry and Catalysis, University of Ulm (Germany); Barth, Clemens [CINAM-CNRS, Marseille (France); Esch, Friedrich; Heiz, Ueli [Department of Chemistry, Technical University of Munich, Garching (Germany); Landman, Uzi [School of Physics, Georgia Institute of Technology, Atlanta, Georgia (United States)

    2010-05-15

    Ultrathin metal oxide films have attracted considerable interest in recent years as versatile substrate for the design of nanocatalytic model systems. In particular, it has been proposed theoretically and confirmed experimentally that the electronic structure of adsorbates can be influenced by the layer thickness and the stoichiometry, i.e., the type and number of defects, of the oxide film. This has important consequences on the chemical reactivity of the oxide surface itself and of oxide supported metal clusters. It also opens new possibilities to influence and to control chemical reactions occurring at the surface of these systems. The present feature focuses on very recent experiments that illustrate the effects of a proper adjustment of layer thickness and composition of ultrathin MgO(100) films on chemical transformations. On the magnesia surface itself, the photodissociation dynamics of methyl iodide molecules is investigated via femtosecond-laser pump-probe mass spectrometry. Furthermore, the catalytic oxidation of carbon monoxide at mass-selected Au{sub 20} clusters deposited on magnesia is explored through temperature programmed reaction measurements. In the latter case, detailed first principles calculations are able to correlate the experimentally observed reactivity with structural dimensionality changes that are induced by the changing thickness and composition of the magnesia support. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  6. Broadband epsilon-near-zero metamaterials based on metal-polymer composite thin films

    Science.gov (United States)

    Pinchuk, Pavlo; Jiang, Ke

    2015-10-01

    Epsilon-near-zero (ENZ) metamaterials are designed to exhibit a near-zero response for the real part of the dielectric permittivity at a given frequency or in a specific frequency range. Typically, this frequency range is relatively small. In this paper, we present an approach to broaden this range by controlling the size of the nanoparticles embedded in a thin film. Noble metal nanoparticles exhibit an external size effect that redshifts the Surface Plasmon Resonance frequency with an increase of the size of the particles. The absorption spectrum of a material can be directly related to its dielectric permittivity via the Kramers-Kronig relations. We use the Kramers-Kronig relations to retrieve the complex effective dielectric permittivity of a composite film, which is designed to exhibit ENZ behavior over a broad frequency range. We synthesize a composite thin film embedded with metal nanoparticles of a broad size distribution. Such a material exhibits a broad SPR, and, in turn, broadband ENZ behavior.

  7. The single molecular precursor approach to metal telluride thin films: imino-bis(diisopropylphosphine tellurides) as examples.

    Science.gov (United States)

    Ritch, Jamie S; Chivers, Tristram; Afzaal, Mohammad; O'Brien, Paul

    2007-10-01

    Interest in metal telluride thin films as components in electronic devices has grown recently. This tutorial review describes the use of single-source precursors for the preparation of metal telluride materials by aerosol-assisted chemical vapour deposition (AACVD) and acquaints the reader with the basic techniques of materials characterization. The challenges in the design and synthesis of suitable precursors are discussed, focusing on metal complexes of the recently-developed imino-bis(diisopropylphosphine telluride) ligand. The generation of thin films and nanoplates of CdTe, Sb(2)Te(3) and In(2)Te(3) from these precursors are used as illustrative examples.

  8. Amino Acid Hydrolysis and Analysis System for Investigation of Site Directed Nucleation and Growth of Ceramic Films on Metallic Surfaces

    Science.gov (United States)

    2008-09-30

    of biomineralization by hemocytes isolated from a bivalve on a metal substrate outside of the organism. These results indicate that it is possible...to deposit a ceramic material onto a metal substrate at ambient temperature and pressure. Figure I A-B. SEM evidence of cellular biomineralization on...hydrolysis and analysis system for investigation of site directed nucleation and growth of cera1nic films on metallic surfaces Sb. GRANT NUMBER

  9. A rapid fractionation method for heavy metals in soil by continuous-flow sequential extraction assisted by focused microwaves.

    Science.gov (United States)

    Nakazato, Tetsuya; Akasaka, Mikio; Tao, Hiroaki

    2006-11-01

    A microwave-assisted continuous-flow sequential extraction system was developed for rapid fractionation analysis of heavy metals in soil. Insertion of pressure-adjusted air between the extractants provided stable flows of the extractants without mutual mixing and back-pressure influence of a column packed with soil, thereby facilitating reliable continuous-flow extractions. In addition, use of pure water as a pumping solvent removed metal contamination because of direct contact between corrosive extractants and the pump containing metallic materials. Focused microwave irradiation to the soil accelerated the selective extractions of the acid-soluble and reducible fractions of heavy metals in soil in the first and second steps of the sequential extraction conditions, as defined by the Commission of the European Bureau of Reference (BCR). The microwave-assisted continuous-flow extraction provided high correlations in amounts of six heavy metals except Zn in the first step and Cu in the second step extracted from a reference sludge soil, BCR CRM 483, with a conventional batchwise extraction proposed by BCR; continuous-flow extraction assisted by conductive heating provided lower correlations for all the six metals. The proposed method drastically reduced the time required for the sequence extraction to ca. 65 min without losing accuracy and precision of the fractionation analysis of heavy metals in soil, whereas the BCR batchwise method requires ca. 33 h.

  10. Direct synthesis of large-area continuous ReS2 films on a flexible glass at low temperature

    Science.gov (United States)

    Kim, Youngchan; Kang, Byunggil; Choi, Yongsuk; Cho, Jeong Ho; Lee, Changgu

    2017-06-01

    Rhenium disulfide (ReS2) has been attracting attentions due to the direct bandgap regardless of the thickness and anisotropic electrical, mechanical and optical properties deriving from its unique crystal lattice structure. In order to utilize these properties, some synthesis methods of ReS2 have been studied for electronic applications. However, their results are not suitable for practical applications because of non-uniformity, discontinuity and difficulty of large-area continuous film growth. Here, we report the synthesis method of layer-controlled wafer-scale (7  ×  2 cm2) ReS2 films by chemical vapor deposition with high uniformity and continuity. Especially, we demonstrate successfully a direct synthesis of ReS2 on a transparent flexible glass substrate at low synthesis temperature (450 °C) without the aid of a catalyst or a plasma enhanced system. The field effect transistors with as-grown ReS2 films on the flexible glass exhibit typical n-type behavior with low threshold voltage of 0.75 V, high on-off ratio of ~105, low subthreshold swing of 260 mV/decade and mobility of 0.13 cm2 V-1 S-1. The direct synthesis of ReS2 films on flexible glass will provide the platform to realize large area transfer-free fabrication of high quality transparent flexible electronic devices.

  11. Determination of photocarrier density under continuous photoirradiation using spectroscopic techniques as applied to polymer: Fullerene blend films

    Energy Technology Data Exchange (ETDEWEB)

    Kanemoto, Katsuichi, E-mail: kkane@sci.osaka-cu.ac.jp; Nakatani, Hitomi; Domoto, Shinya [Department of Physics, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan)

    2014-10-28

    We propose a method to determine the density of photocarrier under continuous photoirradiation in conjugated polymers using spectroscopic signals obtained by photoinduced absorption (PIA) measurements. The bleaching signals in the PIA measurements of polymer films and the steady-state absorption signals of oxidized polymer solution are employed to determine the photocarrier density. The method is applied to photocarriers of poly (3-hexylthiophene) (P3HT) in a blended film consisting of P3HT and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). The photocarrier density under continuous photoirradiation of 580 mW/cm{sup 2} is determined to be 3.5 × 10{sup 16 }cm{sup −3}. Using a trend of the carrier density increasing in proportion to the square root of photo-excitation intensity, we provide a general formula to estimate the photocarrier density under simulated 1 sun solar irradiation for the P3HT: PCBM film of an arbitrary thickness. We emphasize that the method proposed in this study enables an estimate of carrier density without measuring a current and can be applied to films with no electrodes as well as to devices.

  12. New approach for fabricating hybrid-structured metal mesh films for flexible transparent electrodes by the combination of electrospinning and metal deposition

    Science.gov (United States)

    Huh, Jin Woo; Lee, Dong Kyu; Jeon, Hwan-Jin; Ahn, Chi Won

    2016-11-01

    In this study, hybrid-structured metal mesh (HMM) films as potential flexible transparent electrodes, composed of aligned micro-sized metal fibers integrated into random network of metal nanofibers, were fabricated by the combination of electrospinning and metal deposition. These naturally fiber-bridged HMMs, with a gold layer thickness of 85 nm, exhibited a high transmittance of around 90% and a sheet resistance of approximately 10 Ω sq-1, as well as favorable mechanical stability under bending stress. These results demonstrate that the approach employed herein is a simple, highly efficient, and facile process for fabricating, uniform, interconnected fiber networks with potential for producing high-performance flexible transparent electrodes.

  13. Structural, electronic and chemical properties of metal/oxide and oxide/oxide interfaces and thin film structures

    Energy Technology Data Exchange (ETDEWEB)

    Lad, Robert J.

    1999-12-14

    This project focused on three different aspects of oxide thin film systems: (1) Model metal/oxide and oxide/oxide interface studies were carried out by depositing ultra-thin metal (Al, K, Mg) and oxide (MgO, AlO{sub x}) films on TiO{sub 2}, NiO and {alpha}-Al{sub 2}O{sub 3} single crystal oxide substrates. (2) Electron cyclotron resonance (ECR) oxygen plasma deposition was used to fabricate AlO{sub 3} and ZrO{sub 2} films on sapphire substrates, and film growth mechanisms and structural characteristics were investigated. (3) The friction and wear characteristics of ZrO{sub 2} films on sapphire substrates in unlubricated sliding contact were studied and correlated with film microstructure. In these studies, thin film and interfacial regions were characterized using diffraction (RHEED, LEED, XRD), electron spectroscopies (XPS, UPS, AES), microscopy (AFM) and tribology instruments (pin-on-disk, friction microprobe, and scratch tester). By precise control of thin film microstructure, an increased understanding of the structural and chemical stability of interface regions and tribological performance of ultra-thin oxide films was achieved in these important ceramic systems.

  14. Numerical and experimental modeling of liquid metal thin film flows in a quasi-coplanar magentic field

    Energy Technology Data Exchange (ETDEWEB)

    Morley, Neil B. [Univ. of California, Los Angeles, CA (United States)

    1994-01-01

    Liquid metal film protection of plasma-facing surfaces in fusion reactors is proposed in an effort to counter the adverse effects of high heat and particle fluxes from the burning plasma. Concerns still exist about establishing the required flow in presence of strong magnetic fields and plasma momentum flux typical of a reactor environment. In this work, the flow behavior of the film is examined under such conditions. Analysis of MHD equations as they apply to liquid metal flows with a free surface in the fully-developed limit was undertaken. Solution yields data for velocity profiles and uniform film heights vs key design parameters (channel size, magnetic field magnitude/orientation, channel slope, wall conductivity). These results are compared to previous models to determine accuracy of simplifying assumptions, in particular Hartmann averaging of films along {rvec B}. Effect of a plasma momentum flux on the thin films is also analyzed. The plasma momentum is strong enough in the cases examined to seriously upset the film, especially for lighter elements like Li. Ga performed much better and its possible use is bolstered by calculations. In an experiment in the MeGA-loop MHD facility, coplanar, wide film flow was found to be little affected by the magnetic field due to the elongated nature of the film. Both MHD drag and partial laminarization are observed, supporting the fully- developed film model predictions of the onset of MHD drag and duct flow estimations for flow laminarization.

  15. Microstructures of metallic film and diamond growth from Fe-Ni-C system

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The microstructures of metallic film surrounding diamond have been systemically studied using the transmission electron microscopy (TEM) and the atom force microscopy (AFM). The film can be divided into three layers (inner layer near diamond, external layer near graphite and middle layer). The graphite cannot be directly transformed into diamond in the film at HTHP; there exists a parallel relationship between (111) of γ-(Fe,Ni) and (110) of Fe3C in the inner layer; the sawtooth-like step morphology found by AFM on the film is similar to that of corresponding diamond surface. A new model for diamond growth at HPHT is proposed from the parallel relationship and sawtooth-like step morphology. It is believed that Fe3C may be a transitional phase in the course of diamond growth, γ-(Fe,Ni) in the inner layer can absorb carbon atom groups with lamella structure from Fe3C, and then the carbon groups stack on growing diamond.

  16. The influence of chemisorption on the defect equilibrium of metal oxide thin films

    Science.gov (United States)

    Geistlinger, H.

    1996-08-01

    Using the exact charge density of intrinsic point defects of metal oxides (MOs), the phenomenological electron theory of chemisorption, developed by Volkenstein, is applied to acceptorlike and donorlike chemisorption on MO thin films for the whole ξ region (where ξ=D/LD, D is the film thickness, and LD is Debye length). The experimental temperature and oxygen partial pressure dependence of the averaged electron concentration (pO2,T)∝e-EA/kTpO2-m(T) for polycrystalline ZnO films are discussed on the bases of three different models: the Schottky-defect model, the Volkenstein model for electronic equilibrium, and the comprehensive model for complete equilibrium. It turns out that a Schottky-defect model that uses single-crystal-mass action constants will not yield the experimental high temperature limit (T=1000 K: EA=1.6 eV, m=0.26). This limit is obtained using a higher averaged concentration of oxygen vacancies for polycrystalline films (due to the presence of grain boundaries). The comparison between the electronic and complete equilibrium shows that the screening of the surface charge through mobile positively charged oxygen vacancies has a tremendous reducing effect of about 30% of the surface potential in the temperature range considered.

  17. Low Temperature Reactive Sputtering of Thin Aluminum Nitride Films on Metallic Nanocomposites.

    Science.gov (United States)

    Ramadan, Khaled Sayed Elbadawi; Evoy, Stephane

    2015-01-01

    Piezoelectric aluminum nitride thin films were deposited on aluminum-molybdenum (AlMo) metallic nanocomposites using reactive DC sputtering at room temperature. The effect of sputtering parameters on film properties was assessed. A comparative study between AlN grown on AlMo and pure aluminum showed an equivalent (002) crystallographic texture. The piezoelectric coefficients were measured to be 0.5±0.1 C m(-2) and 0.9±0.1 C m(-2), for AlN deposited on Al/0.32Mo and pure Al, respectively. Films grown onto Al/0.32Mo however featured improved surface roughness. Roughness values were measured to be 1.3nm and 5.4 nm for AlN films grown on AlMo and on Al, respectively. In turn, the dielectric constant was measured to be 8.9±0.7 for AlN deposited on Al/0.32Mo seed layer, and 8.7±0.7 for AlN deposited on aluminum; thus, equivalent within experimental error. Compatibility of this room temperature process with the lift-off patterning of the deposited AlN is also reported.

  18. Deposition of highly (111)-oriented PZT thin films by using metal organic chemical deposition

    CERN Document Server

    Bu, K H; Choi, D K; Seong, W K; Kim, J D

    1999-01-01

    Lead zirconate titanate (PZT) thin films have been grown on Pt/Ta/SiNx/Si substrates by using metal organic chemical vapor deposition with Pb(C sub 2 H sub 5) sub 4 , Zr(O-t-C sub 4 H sub 9) sub 4 , and Ti(O-i-C sub 3 H sub 7) sub 4 as source materials and O sub 2 as an oxidizing gas. The Zr fraction in the thin films was controlled by varying the flow rate of the Zr source material. The crystal structure and the electrical properties were investigated as functions of the composition. X-ray diffraction analysis showed that at a certain range of Zr fraction, highly (111)-oriented PZT thin films with no pyrochlore phases were deposited. On the other hand, at low Zr fractions, there were peaks from Pb-oxide phases. At high Zr fractions, peaks from pyrochlore phase were seen. The films also showed good electrical properties, such as a high dielectric constant of more than 1200 and a low coercive voltage of 1.35 V.

  19. Direct observation of atomic-level nucleation and growth processes from an ultrathin metallic glass films

    Energy Technology Data Exchange (ETDEWEB)

    Huang, K. Q.; Cao, C. R.; Sun, Y. T.; Li, J.; Bai, H. Y.; Zheng, D. N., E-mail: l.gu@iphy.ac.cn, E-mail: dzheng@iphy.ac.cn, E-mail: whw@iphy.ac.cn; Wang, W. H., E-mail: l.gu@iphy.ac.cn, E-mail: dzheng@iphy.ac.cn, E-mail: whw@iphy.ac.cn [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Gu, L., E-mail: l.gu@iphy.ac.cn, E-mail: dzheng@iphy.ac.cn, E-mail: whw@iphy.ac.cn [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100190 (China)

    2016-01-07

    Till date, there have been no direct atomic-level experimental observations of the earliest stages of the nucleation and growth processes of nanocrystals formed by thermally induced crystallization in ultrathin metallic glasses (MGs). Here, we present a study of the crystallization process in atomically thin and highly stable MG films using double spherical aberration-corrected scanning transmission electron microscopy (Cs-TEM). Taking advantage of the stability of MG films with a slow crystallization process and the atomic-level high resolution of Cs-TEM, we observe the formation of the nucleus precursor of nanocrystals formed by atom aggregation followed by concomitant coalescence and stepwise evolution of the shape of the nanocrystals with a monodispersed and separated bimodal size distribution. Molecular dynamics simulation of the atomic motion in the glass film on a rigid amorphous substrate confirms the stepwise evolution processes of atom aggregation, cluster formation, cluster movement on the substrate, and cluster coalescence into larger crystalline particles. Our results might provide a better fundamental understanding of the nucleation and growth processes of nanocrystals in thin MG films.

  20. Applications of Cubic MgZnO Thin Films in Metal-Insulator-Silicon Structures

    Institute of Scientific and Technical Information of China (English)

    LIANG Jun; WU Hui-Zhen; LAO Yan-Feng; QIU Dong-Jiang; CHEN Nai-Bo; XU Tian-Ning

    2004-01-01

    @@ Cubic Mgo.55Zno.45O thin film alloys have been deposited on Si substrates at low growth temperature. The topography of the cross section of the epitaxial film by scanning electronic microscope demonstrates good mor phology and high interfacial quality. The high (001) orientation and wide band-gap (Eg > 5.5 eV) of the cubic Mgo.55Zno.45 O thin films accord with the guidelines for metal-insulator-silicon (MIS) device applications. Using the cubic ternary thin films as insulators, MIS structures have been fabricated. The capacitance-voltage measurements show the flat band voltage shift VFB of11.8 V and mobile ion density Dmc of 5.57 × 1010 cm-2 for the MIS structure. Leakage current density as low as ~ 10-7 A/cm2 is obtained at E = 700 kV/cm by the currentvoltage measurements. These unique structural and electrical properties of the fabricated MIS devices indicate that cubic MgZnO materials could become a new candidate for high-κ dielectrics used in silicon integrated circuit technologies.

  1. Active vacuum brazing of CNT films to metal substrates for superior electron field emission performance

    Science.gov (United States)

    Longtin, Rémi; Sanchez-Valencia, Juan Ramon; Shorubalko, Ivan; Furrer, Roman; Hack, Erwin; Elsener, Hansrudolf; Gröning, Oliver; Greenwood, Paul; Rupesinghe, Nalin; Teo, Kenneth; Leinenbach, Christian; Gröning, Pierangelo

    2015-02-01

    The joining of macroscopic films of vertically aligned multiwalled carbon nanotubes (CNTs) to titanium substrates is demonstrated by active vacuum brazing at 820 °C with a Ag-Cu-Ti alloy and at 880 °C with a Cu-Sn-Ti-Zr alloy. The brazing methodology was elaborated in order to enable the production of highly electrically and thermally conductive CNT/metal substrate contacts. The interfacial electrical resistances of the joints were measured to be as low as 0.35 Ω. The improved interfacial transport properties in the brazed films lead to superior electron field-emission properties when compared to the as-grown films. An emission current of 150 μA was drawn from the brazed nanotubes at an applied electric field of 0.6 V μm-1. The improvement in electron field-emission is mainly attributed to the reduction of the contact resistance between the nanotubes and the substrate. The joints have high re-melting temperatures up to the solidus temperatures of the alloys; far greater than what is achievable with standard solders, thus expanding the application potential of CNT films to high-current and high-power applications where substantial frictional or resistive heating is expected.

  2. Fabrication and characterizations of thin film metallic glasses: Antibacterial property and durability study for medical application

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Jinn P., E-mail: jpchu@mail.ntust.edu.tw [Dept. of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Liu, Tz-Yah; Li, Chia-Lin; Wang, Chen-Hao [Dept. of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan (China); Jang, Jason S.C. [Dept. of Mechanical Engineering, National Taiwan Central University, Jhongli 32001, Taiwan (China); Chen, Ming-Jen; Chang, Shih-Hsin; Huang, Wen-Chien [Mackay Memorial Hospital, Taipei 10449, Taiwan (China)

    2014-06-30

    Metallic glasses with the disordered atomic structure have unique properties of high strength, high toughness, good corrosion and abrasion resistances. These materials are thus potentially useful for medical application. In this work, we evaluate the antibacterial property and durability of materials sputter-coated with Zr-based (Zr{sub 53}Cu{sub 33}Al{sub 9}Ta{sub 5}) and Cu-based (Cu{sub 48}Zr{sub 42}Ti{sub 4}Al{sub 6}) thin film metallic glasses (TFMGs). Good adhesive coating of Zr-based TFMG on the dermatome gives rise to blade sharpness improvement of ∼ 27%, substantial surface roughness reduction of ∼ 66% and smoother incised wound on the pig skin. As compared to 48.8° on the bare Si wafer, the water contact angles of 119.5° and 106.6° for Zr- and Cu-based TFMGs, respectively, reveal the hydrophobic characteristic of the coated surfaces. The bacterial adhesion of Escherichia coli and Staphylococcus aureus to both Zr- and Cu-based TFMGs is hindered to different extents. - Highlights: • Thin film metallic glass (TFMG) coatings are evaluated for medical application. • Good adhesive TFMG on the dermatome yields blade sharpness improvement of ∼ 27%. • A reduction of ∼ 66% in surface roughness is observed after coating with TFMG. • Water contact angle measurement reveals the hydrophobic characteristic for TFMGs. • Bacterial adhesion of E. coli and S. aureus to TFMGs is hindered.

  3. Carbon nanotubes paste sensor modified with bismuth film for determination of metallic ions in ethanol fuel

    Directory of Open Access Journals (Sweden)

    Felipe Augusto Gorla

    2015-05-01

    Full Text Available In the present study an anodic stripping voltammetric method using a bismuth film modified carbon nanotubes paste electrode for simultaneous determination of metals Zn2+, Cd2+and Pb2+in ethanol fuel is described. The metallic ions were preconcentrated on the bismuth film in the time and deposition potential of 500 s and -1.2 V and the stripping step was carried out by square wave voltammetry (frequency of 15 Hz, pulse amplitude of 25 mV and potential step of 5 mV. Acetate buffer at 0.1 mol L-1concentration and pH 4.5 was used as support electrolyte. The method showed linearity including the analytical blank up to 48.39 ?g L-1 for the metals and the obtained limits of detection were 3.36, 0.32 and 0.47 ?g L-1for Zn2+, Cd2+and Pb2+, respectively. The proposed method was applied in ethanol fuel samples.

  4. Poly(aryl-ether-ether-ketone) as a Possible Metalized Film Capacitor Dielectric: Accurate Description of the Band Gap Through Ab Initio Calculation

    Science.gov (United States)

    2014-12-01

    Poly(aryl-ether-ether-ketone) as a Possible Metalized Film Capacitor Dielectric: Accurate Description of the Band Gap Through Ab Initio...Possible Metalized Film Capacitor Dielectric: Accurate Description of the Band Gap Through Ab Initio Calculation Janet Ho and Marco Olguin Sensors...a Possible Metalized Film Capacitor Dielectric: Accurate Description of the Band Gap Through Ab Initio Calculation 5a. CONTRACT NUMBER 5b. GRANT

  5. Investigation of superfast deposition of metal oxide and Diamond-Like Carbon thin films by nanosecond Ytterbium (Yb+) fiber laser

    Science.gov (United States)

    Serbezov, V.; Sotirov, S.; Benkhouja, K.; Zawadzka, A.; Sahraoui, B.

    2013-11-01

    Metal oxide (MOx, M: titanium, magnesium) and Diamond-Like Carbon (DLC) thin films were synthesized by Pulsed Laser Deposition (PLD) at room temperature and low vacuum of 2 Pa for MOx and vacuum of 4 × 10-3 Pa for DLC films. A fiber based Ytterbium (Yb+) laser operating in the nanosecond regime at a repetition rate of 20 kHz was used as an ablation source. Dense and smooth thin films with a thickness from 120 to 360 nm and an area of up to 10 cm2 were deposited on glass and stainless steel substrates at high growth rates up to 2 nm/s for a laser intensity of 10-12 J/cm2. The thin films synthesis was compared for two fiber laser modes of operation, at a repetition rate of 20 kHz and with an additional modulation at 1 kHz. The morphology, chemical composition and structure of the obtained thin films were evaluated using optical microscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and Raman spectroscopy. The morphology of the MOx thin films and the deposition rate strongly depend on the fiber laser mode of operation. Very smooth surfaces were obtained for the metal oxide thin films deposited at lower deposition rates in the modulation mode at 1 kHz. The effect of the substrate on the DLC film structure was studied. The films deposited on dielectric substrates were identified as typical tetrahedral (ta-C) DLC with high sp3 content. DLC films on metal substrates were found typical a-C amorphous carbon films with mixing sp2/sp3 bonds.

  6. Flexible strain sensors with high performance based on metallic glass thin film

    Science.gov (United States)

    Xian, H. J.; Cao, C. R.; Shi, J. A.; Zhu, X. S.; Hu, Y. C.; Huang, Y. F.; Meng, S.; Gu, L.; Liu, Y. H.; Bai, H. Y.; Wang, W. H.

    2017-09-01

    Searching strain sensitive materials for electronic skin is of crucial significance because of the restrictions of current materials such as poor electrical conductivity, large energy consumption, complex manufacturing process, and high cost. Here, we report a flexible strain sensor based on the Zr55Cu30Ni5Al10 metallic glass thin film which we name metallic glass skin. The metallic glass skin, synthesized by ion beam deposition, exhibits piezoresistance effects with a gauge factor of around 2.86, a large detectable strain range (˜1% or 180° bending angle), and good conductivity. Compared to other e-skin materials, the temperature coefficient of resistance of the metallic glass skin is extremely low (9.04 × 10-6 K-1), which is essential for the reduction in thermal drift. In addition, the metallic glass skin exhibits distinct antibacterial behavior desired for medical applications, also excellent reproducibility and repeatability (over 1000 times), nearly perfect linearity, low manufacturing cost, and negligible energy consumption, all of which are required for electronic skin for practical applications.

  7. Optimization of synthesis protocols to control the nanostructure and the morphology of metal oxide thin films for memristive applications

    Energy Technology Data Exchange (ETDEWEB)

    Baldi, G., E-mail: giacomo.baldi@cnr.it; Bosi, M.; Attolini, G.; Berzina, T.; Mosca, R.; Ponraj, J. S.; Iannotta, S. [IMEM-CNR Institute, Parco Area delle Scienze 37/A, I-43124 Parma (Italy); Giusti, G.; Nozar, P.; Toccoli, T.; Verucchi, R. [IMEM-CNR Institute, Via alla Cascata 56/C, Povo – I-38123 Trento (Italy); Collini, C.; Lorenzelli, L. [FBK Bruno Kessler Foundation, Via Sommarive 18, I-38123 Trento (Italy)

    2015-03-10

    We propose a multi-technique approach based on in-vacuum synthesis of metal oxides to optimize the memristive properties of devices that use a metal oxide thin film as insulating layer. Pulsed Microplasma Cluster Source (PMCS) is based on supersonic beams seeded by clusters of the metal oxide. Nanocrystalline TiO{sub 2} thin films can be grown at room temperature, controlling the oxide stoichiometry from titanium metal up to a significant oxygen excess. Pulsed Electron beam Deposition (PED) is suitable to grow crystalline thin films on large areas, a step towards producing device arrays with controlled morphology and stoichiometry. Atomic Layer Deposition (ALD) is a powerful technique to grow materials layer-by-layer, finely controlling the chemical and structural properties of the film up to thickness of 50-80 nm. We will present a few examples of metal-insulator-metal structures showing a pinched hysteresis loop in their current-voltage characteristic. The structure, stoichiometry and morphology of the metal oxide layer, either aluminum oxide or titanium dioxide, is investigated by means of scanning electron microscopy (SEM) and by Raman scattering.

  8. Metal/Diamond Composite Thin-Film Electrodes: New Carbon Supported Catalytic Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Greg M. Swain, PI

    2009-03-10

    The DOE-funded research conducted by the Swain group was focused on (i) understanding structure-function relationships at boron-doped diamond thin-film electrodes, (ii) understanding metal phase formation on diamond thin films and developing electrochemical approaches for producing highly dispersed electrocatalyst particles (e.g., Pt) of small nominal particle size, (iii) studying the electrochemical activity of the electrocatalytic electrodes for hydrogen oxidation and oxygen reduction and (iv) conducting the initial synthesis of high surface area diamond powders and evaluating their electrical and electrochemical properties when mixed with a Teflon binder. (Note: All potentials are reported versus Ag/AgCl (sat'd KCl) and cm{sup 2} refers to the electrode geometric area, unless otherwise stated).

  9. Rare-metal-free high-performance Ga-Sn-O thin film transistor

    Science.gov (United States)

    Matsuda, Tokiyoshi; Umeda, Kenta; Kato, Yuta; Nishimoto, Daiki; Furuta, Mamoru; Kimura, Mutsumi

    2017-03-01

    Oxide semiconductors have been investigated as channel layers for thin film transistors (TFTs) which enable next-generation devices such as high-resolution liquid crystal displays (LCDs), organic light emitting diode (OLED) displays, flexible electronics, and innovative devices. Here, high-performance and stable Ga-Sn-O (GTO) TFTs were demonstrated for the first time without the use of rare metals such as In. The GTO thin films were deposited using radiofrequency (RF) magnetron sputtering. A high field effect mobility of 25.6 cm2/Vs was achieved, because the orbital structure of Sn was similar to that of In. The stability of the GTO TFTs was examined under bias, temperature, and light illumination conditions. The electrical behaviour of the GTO TFTs was more stable than that of In-Ga-Zn-O (IGZO) TFTs, which was attributed to the elimination of weak Zn-O bonds.

  10. Metal-assisted chemical etching of CIGS thin films for grain size analysis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Chaowei [Research and Development Centre, Hanergy Thin Film Power Group Limited, Chengdu (China); Loi, Huu-Ha; Duong, Anh; Parker, Magdalena [Failure Analysis Department, MiaSole Hi-Tech Corp., Santa Clara, CA (United States)

    2016-09-15

    Grain size of the CIGS absorber is an important monitoring factor in the CIGS solar cell manufacturing. Electron backscatter diffraction (EBSD) analysis is commonly used to perform CIGS grain size analysis in the scanning electron microscope (SEM). Although direct quantification on SEM image using the average grain intercept (AGI) method is faster and simpler than EBSD, it is hardly applicable on CIGS thin films. The challenge is that, not like polycrystalline silicon, to define grain boundaries by selective chemical etching is not easily realizable for the multi-component CIGS alloy. In this Letter, we present direct quantification of CIGS thin film grain size using the AGI method by developing metal-assisted wet chemical etching process to define CIGS grain boundaries. The calculated value is similar to EBSD result. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. The effect of polyimide imidization conditions on adhesion strength of thin metal films on polyimide substrates

    CERN Document Server

    Yoo, S H

    1999-01-01

    The effects of Ar sup + RF plasma precleaning and polyimide curing conditions on the peel strength between Al thin films and polyimides have been studied. The BPDA-PDA polyimide precursor of PI-2611 (Du pont) was spin-coated and cured under various imidization conditions. The cured polyimide substrates were in-situ AR sup + RF plasma cleaned prior to metal deposition. Al-1 % Si-0.5 % Cu thin films were deposited onto the polyimide substrates by using DC magnetron sputtering. The peel strength was enhanced by Ar sup + RF plasma precleaning. The Al/modified PI specimen failed cohesively in the polyimide. The polyimide curing conditions strongly affect the peel strength in the Al/modified PI system.

  12. Electron scattering characteristics of polycrystalline metal transition films by in-situ electrical resistance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Trindade, I.G. [Faculdade de Ciencias da Universidade do Porto, Physics Department, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); IFIMUP and IN, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)], E-mail: i_trindade@msn.com; Leitao, D. [IFIMUP and IN, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Fermento, R. [Instituto de Microelectronica de Madrid, Isaac Newton 8, 28760 Tres Cantos, Madrid (Spain); Pogorelev, Y.; Sousa, J.B. [Faculdade de Ciencias da Universidade do Porto, Physics Department, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); IFIMUP and IN, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2009-08-15

    In-situ electrical resistance measurements were performed to obtain the scattering characteristics of very thin polycrystalline metal transition magnetic alloys grown by ion beam deposition (IBD) on specific underlayers. The experimental curves show size effects at small film thicknesses and important differences between Co{sub 85}Fe{sub 15} and Ni{sub 81}Fe{sub 19} thin layers grown on identical underlayers of Ta70 A/Ru13 A. The largest difference was observed in Ni{sub 81}Fe{sub 19} films grown on underlayers of amorphous Ta70 A. The experimental curves of electrical resistivity/conductivity variation with layer thickness were well fit within the Mayadas and Shatzkes (M-S) model, assuming specific formulations for grain growth with layer thickness.

  13. Evaluation of the adhesion strength of diamond films brazed on K-10 type hard metal

    Directory of Open Access Journals (Sweden)

    Santos Sérgio Ivan dos

    2004-01-01

    Full Text Available The coating of cutting tools with diamond films considerably increases the tool performance due to the combination of the unique tribological properties of diamond with the bulk properties of the substrate (toughness. The tool performance, however, is strongly related to the adhesion strength between the film and the substrate. In this work our main goal was to propose and to test a procedure, based on a tensile strength test, to evaluate the adhesion strength of a diamond wafer brazed on a hard metal substrate, taking into account the effect of the brazing temperature and time. The temperature range studied was from 800 to 980 °C and the brazing time ranged from 3 to 40 min. The obtained results could be used to optimize the costs and time required to the production of high performance cutting tools with brazed diamond wafers.

  14. New strain states and radical property tuning of metal oxides using a nanocomposite thin film approach

    Directory of Open Access Journals (Sweden)

    Judith MacManus-Driscoll

    2015-06-01

    Full Text Available Auxetic-like strain states were generated in self-assembled nanocomposite thin films of (Ba0.6Sr0.4TiO31−x − (Sm2O3x(BSTO − SmO. A switch from auxetic-like to elastic-like strain behavior was observed for x > 0.50, when the SmO switched from being nanopillars in the BSTO matrix to being the matrix with BSTO nanopillars embedded in it. A simple model was adopted to explain how in-plane strain varies with x. At high x (0.75, strongly enhanced ferroelectric properties were obtained compared to pure BSTO films. The nanocomposite method represents a powerful new way to tune the properties of a wide range of strongly correlated metal oxides whose properties are very sensitive to strain.

  15. Laser Treatment of Nanoparticulated Metal Thin Films for Ceramic Tile Decoration.

    Science.gov (United States)

    Rico, V J; Lahoz, R; Rey-García, F; Yubero, F; Espinós, J P; de la Fuente, G F; González-Elipe, A R

    2016-09-21

    This paper presents a new method for the fabrication of metal-like decorative layers on glazed ceramic tiles. It consists of the laser treatment of Cu thin films prepared by electron-beam evaporation at glancing angles. A thin film of discontinuous Cu nanoparticles was electron-beam-evaporated in an oblique angle configuration onto ceramic tiles and an ample palette of colors obtained by laser treatment both in air and in vacuum. Scanning electron microscopy along with UV-vis-near-IR spectroscopy and time-of-flight secondary ion mass spectrometry analysis were used to characterize the differently colored layers. On the basis of these analyses, color development has been accounted for by a simple model considering surface melting phenomena and different microstructural and chemical transformations of the outmost surface layers of the samples.

  16. Fe-B-Nd-Nb metallic glass thin films for microelectromechanical systems

    Science.gov (United States)

    Phan, T. A.; Oguchi, H.; Hara, M.; Shikida, M.; Hida, H.; Ando, T.; Sato, K.; Kuwano, H.

    2013-10-01

    In the present study, we investigate the mechanical properties, residual stress, and microprocessing compatibility of Fe67.5B22.5Nd6.3Nb3.7 metallic glass thin films (Fe-MGTFs). The mechanical properties are measured using a specially designed microtensile tester. The fracture toughness of the Fe-MGTF (6.36 MPa × m1/2) is more than twice that of Si, and the highest among the thin films developed for microelectromechanical systems (MEMS) to this point. In addition, the fabrication of freestanding microcantilevers illustrates the low residual stress and high microprocessing compatibility of Fe-MGTFs. The present study verifies the great potential of Fe-MGTFs for use in MEMS.

  17. Spin-polarized spin-orbit-split quantum-well states in a metal film

    Energy Technology Data Exchange (ETDEWEB)

    Varykhalov, Andrei; Sanchez-Barriga, Jaime; Gudat, Wolfgang; Eberhardt, Wolfgang; Rader, Oliver [BESSY Berlin (Germany); Shikin, Alexander M. [St. Petersburg State University (Russian Federation)

    2008-07-01

    Elements with high atomic number Z lead to a large spin-orbit coupling. Such materials can be used to create spin-polarized electronic states without the presence of a ferromagnet or an external magnetic field if the solid exhibits an inversion asymmetry. We create large spin-orbit splittings using a tungsten crystal as substrate and break the structural inversion symmetry through deposition of a gold quantum film. Using spin- and angle-resolved photoelectron spectroscopy, it is demonstrated that quantum-well states forming in the gold film are spin-orbit split and spin polarized up to a thickness of at least 10 atomic layers. This is a considerable progress as compared to the current literature which reports spin-orbit split states at metal surfaces which are either pure or covered by at most a monoatomic layer of adsorbates.

  18. Thin film three-dimensional topological insulator metal-oxide-semiconductor field-effect-transistors: A candidate for sub-10 nm devices

    Energy Technology Data Exchange (ETDEWEB)

    Akhavan, N. D., E-mail: nima.dehdashti@uwa.edu.au; Jolley, G.; Umana-Membreno, G. A.; Antoszewski, J.; Faraone, L. [Department of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, WA 6009 (Australia)

    2014-08-28

    Three-dimensional (3D) topological insulators (TI) are a new state of quantum matter in which surface states reside in the bulk insulating energy bandgap and are protected by time-reversal symmetry. It is possible to create an energy bandgap as a consequence of the interaction between the conduction band and valence band surface states from the opposite surfaces of a TI thin film, and the width of the bandgap can be controlled by the thin film thickness. The formation of an energy bandgap raises the possibility of thin-film TI-based metal-oxide-semiconductor field-effect-transistors (MOSFETs). In this paper, we explore the performance of MOSFETs based on thin film 3D-TI structures by employing quantum ballistic transport simulations using the effective continuous Hamiltonian with fitting parameters extracted from ab-initio calculations. We demonstrate that thin film transistors based on a 3D-TI structure provide similar electrical characteristics compared to a Si-MOSFET for gate lengths down to 10 nm. Thus, such a device can be a potential candidate to replace Si-based MOSFETs in the sub-10 nm regime.

  19. CONTROL STRATEGY OF A PARALLEL HYBRID CAR WITH A METAL BELT-PLANETARY GEAR CONTINUOUSLY VARIABLE TRANSMISSION SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The most remarkable characteristic of a metal belt-planetary gear continuously variable transmission is a wider ratio range and a bigger torque capacity than a conventional metal pushing belt continuously variable transmission. A parallel hybrid car with this transmission system not only can reduce fuel consumption and pollutant emission at a ECE city cycle, but also can keep the motor working in the most efficiency area and can be started by a lower power motor by oneself. At the same time, the continuously variable transmission system can realize the smooth switch between the motor and the engine.

  20. Continuous Ultra-Thin MOS2 Films Grown by Low-Temperature Physical Vapor Deposition (Postprint)

    Science.gov (United States)

    2014-07-01

    films are composed of nano -scale domains with strong chemical binding between domain boundaries, allowing lift-off from the substrate and electronic...process yields materials with key optical and electronic properties identical to exfoliated layers. The films are composed of nano -scale domains with...with a layered atomic structure giving rise to remarkable me- chanical (e.g., low shear strength for solid lubrication )1 and catalytic (e.g