National Library of Energy BETA

Sample records for thin-film amorphous silicon

  1. Optically activated sub-millimeter dielectric relaxation in amorphous thin film silicon at room temperature

    SciTech Connect (OSTI)

    Rahman, Rezwanur; Ohno, Tim R.; Taylor, P. C.; Scales, John A.

    2014-05-05

    Knowing the frequency-dependent photo-induced complex conductivity of thin films is useful in the design of photovoltaics and other semi-conductor devices. For example, annealing in the far-infrared could in principle be tailored to the specific dielectric properties of a particular sample. The frequency dependence of the conductivity (whether dark or photo-induced) also gives insight into the effective dimensionality of thin films (via the phonon density of states) as well as the presence (or absence) of free carriers, dopants, defects, etc. Ultimately, our goal is to make low-noise, phase-sensitive room temperature measurements of the frequency-dependent conductivity of thin films from microwave frequencies into the far-infrared; covering, the frequency range from ionic and dipole relaxation to atomic and electronic processes. To this end, we have developed a high-Q (quality factor) open cavity resonator capable of resolving the complex conductivity of sub-micron films in the range of 100350?GHz (0.10.35 THz, or 0.41?meV). In this paper, we use a low-power green laser to excite bound charges in high-resistivity amorphous silicon thin film. Even at room temperature, we can resolve both the dark conductivity and photo-induced changes associated with dielectric relaxation and possibly some small portion of free carriers.

  2. Size effects on the thermal conductivity of amorphous silicon thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Thomas Edwin Beechem; Braun, Jeffrey L.; Baker, Christopher H.; Elahi, Miraz; Artyushkova, Kateryna; Norris, Pamela M.; Leseman, Zayd Chad; Gaskins, John T.; Hopkins, Patrick E.; Giri, Ashutosh

    2016-04-01

    In this study, we investigate thickness-limited size effects on the thermal conductivity of amorphous silicon thin films ranging from 3 to 1636 nm grown via sputter deposition. While exhibiting a constant value up to ~100 nm, the thermal conductivity increases with film thickness thereafter. The thickness dependence we demonstrate is ascribed to boundary scattering of long wavelength vibrations and an interplay between the energy transfer associated with propagating modes (propagons) and nonpropagating modes (diffusons). A crossover from propagon to diffuson modes is deduced to occur at a frequency of ~1.8 THz via simple analytical arguments. These results provide empirical evidencemore » of size effects on the thermal conductivity of amorphous silicon and systematic experimental insight into the nature of vibrational thermal transport in amorphous solids.« less

  3. Microstructure factor and mechanical and electronic properties of hydrogenated amorphous and nanocrystalline silicon thin-films for microelectromechanical systems applications

    SciTech Connect (OSTI)

    Mouro, J.; Gualdino, A.; Chu, V. [Instituto de Engenharia de Sistemas e Computadores Microsistemas e Nanotecnologias (INESC-MN) and IN Institute of Nanoscience and Nanotechnology, 1000-029 Lisbon (Portugal); Conde, J. P. [Instituto de Engenharia de Sistemas e Computadores Microsistemas e Nanotecnologias (INESC-MN) and IN Institute of Nanoscience and Nanotechnology, 1000-029 Lisbon (Portugal); Department of Bioengineering, Instituto Superior Tcnico (IST), 1049-001 Lisbon (Portugal)

    2013-11-14

    Thin-film silicon allows the fabrication of MEMS devices at low processing temperatures, compatible with monolithic integration in advanced electronic circuits, on large-area, low-cost, and flexible substrates. The most relevant thin-film properties for applications as MEMS structural layers are the deposition rate, electrical conductivity, and mechanical stress. In this work, n{sup +}-type doped hydrogenated amorphous and nanocrystalline silicon thin-films were deposited by RF-PECVD, and the influence of the hydrogen dilution in the reactive mixture, the RF-power coupled to the plasma, the substrate temperature, and the deposition pressure on the structural, electrical, and mechanical properties of the films was studied. Three different types of silicon films were identified, corresponding to three internal structures: (i) porous amorphous silicon, deposited at high rates and presenting tensile mechanical stress and low electrical conductivity, (ii) dense amorphous silicon, deposited at intermediate rates and presenting compressive mechanical stress and higher values of electrical conductivity, and (iii) nanocrystalline silicon, deposited at very low rates and presenting the highest compressive mechanical stress and electrical conductivity. These results show the combinations of electromechanical material properties available in silicon thin-films and thus allow the optimized selection of a thin silicon film for a given MEMS application. Four representative silicon thin-films were chosen to be used as structural material of electrostatically actuated MEMS microresonators fabricated by surface micromachining. The effect of the mechanical stress of the structural layer was observed to have a great impact on the device resonance frequency, quality factor, and actuation force.

  4. Fluorination of amorphous thin-film materials with xenon fluoride

    DOE Patents [OSTI]

    Weil, Raoul B. (Haifa, IL)

    1988-01-01

    A method is disclosed for producing fluorine-containing amorphous semiconductor material, preferably comprising amorphous silicon. The method includes depositing amorphous thin-film material onto a substrate while introducing xenon fluoride during the film deposition process.

  5. Fluorination of amorphous thin-film materials with xenon fluoride

    DOE Patents [OSTI]

    Weil, R.B.

    1987-05-01

    A method is disclosed for producing fluorine-containing amorphous semiconductor material, preferably comprising amorphous silicon. The method includes depositing amorphous thin-film material onto a substrate while introducing xenon fluoride during the film deposition process.

  6. Picosecond and nanosecond laser annealing and simulation of amorphous silicon thin films for solar cell applications

    SciTech Connect (OSTI)

    Theodorakos, I.; Zergioti, I.; Tsoukalas, D.; Raptis, Y. S.; Vamvakas, V.

    2014-01-28

    In this work, a picosecond diode pumped solid state laser and a nanosecond Nd:YAG laser have been used for the annealing and the partial nano-crystallization of an amorphous silicon layer. These experiments were conducted as an alternative/complementary to plasma-enhanced chemical vapor deposition method for fabrication of micromorph tandem solar cell. The laser experimental work was combined with simulations of the annealing process, in terms of temperature distribution evolution, in order to predetermine the optimum annealing conditions. The annealed material was studied, as a function of several annealing parameters (wavelength, pulse duration, fluence), as far as it concerns its structural properties, by X-ray diffraction, SEM, and micro-Raman techniques.

  7. Impact of solid-phase crystallization of amorphous silicon on the chemical structure of the buried Si/ZnO thin film solar cell interface

    SciTech Connect (OSTI)

    Bar, M.; Wimmer, M.; Wilks, R. G.; Roczen, M.; Gerlach, D.; Ruske, F.; Lips, K.; Rech, B.; Weinhardt, L.; Blum, M.; Pookpanratana, S.; Krause, S.; Zhang, Y.; Heske, C.; Yang, W.; Denlinger, J. D.

    2010-04-30

    The chemical interface structure between phosphorus-doped hydrogenated amorphous silicon and aluminum-doped zinc oxide thin films is investigated with soft x-ray emission spectroscopy (XES) before and after solid-phase crystallization (SPC) at 600C. In addition to the expected SPC-induced phase transition from amorphous to polycrystalline silicon, our XES data indicates a pronounced chemical interaction at the buried Si/ZnO interface. In particular, we find an SPC-enhanced formation of Si-O bonds and the accumulation of Zn in close proximity to the interface. For an assumed closed and homogeneous SiO2 interlayer, an effective thickness of (5+2)nm after SPC could be estimated.

  8. Research on high-efficiency, multiple-gap, multijunction, amorphous-silicon-based alloy thin-film solar cells

    SciTech Connect (OSTI)

    Guha, S. )

    1989-06-01

    This report presents results of research on advancing our understanding of amorphous-silicon-based alloys and their use in small-area multijunction solar cells. The principal objectives of the program are to develop a broad scientific base for the chemical, structural, optical, and electronic properties of amorphous-silicon-based alloys; to determine the optimum properties of these alloy materials as they relate to high-efficiency cells; to determine the optimum device configuration for multijunction cells; and to demonstrate proof-of-concept, multijunction, a-Si-alloy-based solar cells with 18% efficiency under standard AM1.5 global insolation conditions and with an area of at least 1 cm{sup 2}. A major focus of the work done during this reporting period was the optimization of a novel, multiple-graded structure that enhances cell efficiency through band-gap profiling. The principles of the operation of devices incorporating such a structure, computer simulations of those, and experimental results for both single- and multijunction cells prepared by using the novel structure are discussed in detail. 14 refs., 35 figs., 7 tabs.

  9. Method of producing amorphous thin films

    DOE Patents [OSTI]

    Brusasco, Raymond M.

    1992-01-01

    Disclosed is a method of producing thin films by sintering which comprises: a. coating a substrate with a thin film of an inorganic glass forming parulate material possessing the capability of being sintered, and b. irridiating said thin film of said particulate material with a laser beam of sufficient power to cause sintering of said material below the temperature of liquidus thereof. Also disclosed is the article produced by the method claimed.

  10. Understanding the Structure of Amorphous Thin Film Hafnia - Final Paper

    SciTech Connect (OSTI)

    Miranda, Andre

    2015-08-27

    Hafnium Oxide (HfO2) amorphous thin films are being used as gate oxides in transistors because of their high dielectric constant (κ) over Silicon Dioxide. The present study looks to find the atomic structure of HfO2 thin films which hasn’t been done with the technique of this study. In this study, two HfO2 samples were studied. One sample was made with thermal atomic layer deposition (ALD) on top of a Chromium and Gold layer on a silicon wafer. The second sample was made with plasma ALD on top of a Chromium and Gold layer on a Silicon wafer. Both films were deposited at a thickness of 50nm. To obtain atomic structure information, Grazing Incidence X-ray diffraction (GIXRD) was carried out on the HfO2 samples. Because of this, absorption, footprint, polarization, and dead time corrections were applied to the scattering intensity data collected. The scattering curves displayed a difference in structure between the ALD processes. The plasma ALD sample showed the broad peak characteristic of an amorphous structure whereas the thermal ALD sample showed an amorphous structure with characteristics of crystalline materials. This appears to suggest that the thermal process results in a mostly amorphous material with crystallites within. Further, the scattering intensity data was used to calculate a pair distribution function (PDF) to show more atomic structure. The PDF showed atom distances in the plasma ALD sample had structure up to 10 Å, while the thermal ALD sample showed the same structure below 10 Å. This structure that shows up below 10 Å matches the bond distances of HfO2 published in literature. The PDF for the thermal ALD sample also showed peaks up to 20 Å, suggesting repeating atomic spacing outside the HfO2 molecule in the sample. This appears to suggest that there is some crystalline structure within the thermal ALD sample.

  11. Near single-crystalline, high-carrier-mobility silicon thin film on a polycrystalline/amorphous substrate

    DOE Patents [OSTI]

    Findikoglu, Alp T.; Jia, Quanxi; Arendt, Paul N.; Matias, Vladimir; Choi, Woong

    2009-10-27

    A template article including a base substrate including: (i) a base material selected from the group consisting of polycrystalline substrates and amorphous substrates, and (ii) at least one layer of a differing material upon the surface of the base material; and, a buffer material layer upon the base substrate, the buffer material layer characterized by: (a) low chemical reactivity with the base substrate, (b) stability at temperatures up to at least about 800.degree. C. under low vacuum conditions, and (c) a lattice crystal structure adapted for subsequent deposition of a semiconductor material; is provided, together with a semiconductor article including a base substrate including: (i) a base material selected from the group consisting of polycrystalline substrates and amorphous substrates, and (ii) at least one layer of a differing material upon the surface of the base material; and, a buffer material layer upon the base substrate, the buffer material layer characterized by: (a) low chemical reactivity with the base substrate, (b) stability at temperatures up to at least about 800.degree. C. under low vacuum conditions, and (c) a lattice crystal structure adapted for subsequent deposition of a semiconductor material, and, a top-layer of semiconductor material upon the buffer material layer.

  12. Amorphous silicon ionizing particle detectors

    DOE Patents [OSTI]

    Street, R.A.; Mendez, V.P.; Kaplan, S.N.

    1988-11-15

    Amorphous silicon ionizing particle detectors having a hydrogenated amorphous silicon (a--Si:H) thin film deposited via plasma assisted chemical vapor deposition techniques are utilized to detect the presence, position and counting of high energy ionizing particles, such as electrons, x-rays, alpha particles, beta particles and gamma radiation. 15 figs.

  13. Amorphous silicon ionizing particle detectors

    DOE Patents [OSTI]

    Street, Robert A.; Mendez, Victor P.; Kaplan, Selig N.

    1988-01-01

    Amorphous silicon ionizing particle detectors having a hydrogenated amorphous silicon (a--Si:H) thin film deposited via plasma assisted chemical vapor deposition techniques are utilized to detect the presence, position and counting of high energy ionizing particles, such as electrons, x-rays, alpha particles, beta particles and gamma radiation.

  14. The silicon/zinc oxide interface in amorphous silicon-based thin-film solar cells: Understanding an empirically optimized contact

    SciTech Connect (OSTI)

    Gerlach, D.; Wilks, R. G.; Wimmer, M.; Felix, R.; Gorgoi, M.; Lips, K.; Rech, B.; Wippler, D.; Mueck, A.; Meier, M.; Huepkes, J.; Lozac'h, M.; Ueda, S.; Sumiya, M.; Yoshikawa, H.; Kobayashi, K.; Baer, M.

    2013-07-08

    The electronic structure of the interface between the boron-doped oxygenated amorphous silicon 'window layer' (a-SiO{sub x}:H(B)) and aluminum-doped zinc oxide (ZnO:Al) was investigated using hard x-ray photoelectron spectroscopy and compared to that of the boron-doped microcrystalline silicon ({mu}c-Si:H(B))/ZnO:Al interface. The corresponding valence band offsets have been determined to be (-2.87 {+-} 0.27) eV and (-3.37 {+-} 0.27) eV, respectively. A lower tunnel junction barrier height at the {mu}c-Si:H(B)/ZnO:Al interface compared to that at the a-SiO{sub x}:H(B)/ZnO:Al interface is found and linked to the higher device performances in cells where a {mu}c-Si:H(B) buffer between the a-Si:H p-i-n absorber stack and the ZnO:Al contact is employed.

  15. Silicon Oxynitride Thin Film Barriers for PV Packaging (Poster)

    SciTech Connect (OSTI)

    del Cueto, J. A.; Glick, S. H.; Terwilliger, K. M.; Jorgensen, G. J.; Pankow, J. W.; Keyes, B. M.; Gedvilas, L. M.; Pern, F. J.

    2006-10-03

    Dielectric, adhesion-promoting, moisture barriers comprised of silicon oxynitride thin film materials (SiOxNy with various material stoichiometric compositions x,y) were applied to: 1) bare and pre-coated soda-lime silicate glass (coated with transparent conductive oxide SnO2:F and/or aluminum), and polymer substrates (polyethylene terephthalate, PET, or polyethylene napthalate, PEN); plus 2) pre- deposited photovoltaic (PV) cells and mini-modules consisting of amorphous silicon (a-Si) and copper indium gallium diselenide (CIGS) thin-film PV technologies. We used plasma enhanced chemical vapor deposition (PECVD) process with dilute silane, nitrogen, and nitrous oxide/oxygen gas mixtures in a low-power (< or = 10 milliW per cm2) RF discharge at ~ 0.2 Torr pressure, and low substrate temperatures < or = 100(degrees)C, over deposition areas ~ 1000 cm2. Barrier properties of the resulting PV cells and coated-glass packaging structures were studied with subsequent stressing in damp-heat exposure at 85(degrees)C/85% RH. Preliminary results on PV cells and coated glass indicate the palpable benefits of the barriers in mitigating moisture intrusion and degradation of the underlying structures using SiOxNy coatings with thicknesses in the range of 100-200 nm.

  16. Flexible Thin-Film Silicon Solar Cells

    SciTech Connect (OSTI)

    Vijh, Aarohi; Cao, Simon; Mohring, Brad

    2014-01-11

    High fuel costs, environmental concerns and issues of national energy security have brought increasing attention to a distributed generation program for electricity based on solar technology. Rooftop photovoltaic (PV) systems provide distributed generation since the power is consumed at the point of production, thus eliminating the need for costly additional transmission lines. However, most current photovoltaic modules are heavy and require a significant amount of labor and accessory hardware such as mounting frames for installation on rooftops. This makes rooftop systems impractical or cost prohibitive in many instances. Under this project, Xunlight has advanced its manufacturing process for the production of lightweight, flexible thin-film silicon based photovoltaic modules, and has enhanced the reliability and performance of Xunlights products. These modules are easily unrolled and adhered directly to standard commercial roofs without mounting structures or integrated directly into roofing membrane materials for the lowest possible installation costs on the market. Importantly, Xunlight has now established strategic alliances with roofing material manufacturers and other OEMs for the development of building integrated photovoltaic roofing and other PV-enabled products, and has deployed its products in a number of commercial installations with these business partners.

  17. Method for producing silicon thin-film transistors with enhanced forward current drive

    DOE Patents [OSTI]

    Weiner, Kurt H.

    1998-01-01

    A method for fabricating amorphous silicon thin film transistors (TFTs) with a polycrystalline silicon surface channel region for enhanced forward current drive. The method is particularly adapted for producing top-gate silicon TFTs which have the advantages of both amorphous and polycrystalline silicon TFTs, but without problem of leakage current of polycrystalline silicon TFTs. This is accomplished by selectively crystallizing a selected region of the amorphous silicon, using a pulsed excimer laser, to create a thin polycrystalline silicon layer at the silicon/gate-insulator surface. The thus created polysilicon layer has an increased mobility compared to the amorphous silicon during forward device operation so that increased drive currents are achieved. In reverse operation the polysilicon layer is relatively thin compared to the amorphous silicon, so that the transistor exhibits the low leakage currents inherent to amorphous silicon. A device made by this method can be used, for example, as a pixel switch in an active-matrix liquid crystal display to improve display refresh rates.

  18. Method for producing silicon thin-film transistors with enhanced forward current drive

    DOE Patents [OSTI]

    Weiner, K.H.

    1998-06-30

    A method is disclosed for fabricating amorphous silicon thin film transistors (TFTs) with a polycrystalline silicon surface channel region for enhanced forward current drive. The method is particularly adapted for producing top-gate silicon TFTs which have the advantages of both amorphous and polycrystalline silicon TFTs, but without problem of leakage current of polycrystalline silicon TFTs. This is accomplished by selectively crystallizing a selected region of the amorphous silicon, using a pulsed excimer laser, to create a thin polycrystalline silicon layer at the silicon/gate-insulator surface. The thus created polysilicon layer has an increased mobility compared to the amorphous silicon during forward device operation so that increased drive currents are achieved. In reverse operation the polysilicon layer is relatively thin compared to the amorphous silicon, so that the transistor exhibits the low leakage currents inherent to amorphous silicon. A device made by this method can be used, for example, as a pixel switch in an active-matrix liquid crystal display to improve display refresh rates. 1 fig.

  19. NREL: Energy Analysis - Crystalline Silicon and Thin Film Photovoltaic

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Results - Life Cycle Assessment Harmonization Crystalline Silicon and Thin Film Photovoltaic Results - Life Cycle Assessment Harmonization Life Cycle Greenhouse Gas Emissions from Solar Photovoltaics (Fact Sheet) Cover of the Life Cycle Greenhouse Gas Emissions from Solar Photovoltaics factsheet Download the Fact Sheet Over the last 30 years, hundreds of life cycle assessments (LCAs) have been conducted and published for a variety of residential and utility-scale solar photovoltaic (PV)

  20. Formation of thin-film resistors on silicon substrates

    DOE Patents [OSTI]

    Schnable, George L.; Wu, Chung P.

    1988-11-01

    The formation of thin-film resistors by the ion implantation of a metallic conductive layer in the surface of a layer of phosphosilicate glass or borophosphosilicate glass which is deposited on a silicon substrate. The metallic conductive layer materials comprise one of the group consisting of tantalum, ruthenium, rhodium, platinum and chromium silicide. The resistor is formed and annealed prior to deposition of metal, e.g. aluminum, on the substrate.

  1. Progress in thin film solar photovoltaic technologies

    SciTech Connect (OSTI)

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

    1991-01-01

    This paper focuses on the rapid recent advances made by thin film solar cell technologies, namely, amorphous silicon, copper indium diselenide, and cadmium telluride. It also indicates the several advantages of thin films. Various consumer products and power applications using thin film solar cells are also discussed. The increasing interest among the utilities for PV system applications is also elucidated.

  2. Spectroscopic ellipsometry characterization of thin-film silicon nitride

    SciTech Connect (OSTI)

    Jellison, G.E. Jr.; Modine, F.A.; Doshi, P.; Rohatgi, A.

    1997-05-01

    We have measured and analyzed the optical characteristics of a series of silicon nitride thin films prepared by plasma-enhanced chemical vapor deposition on silicon substrates for photovoltaic applications. Spectroscopic ellipsometry measurements were made by using a two-channel spectroscopic polarization modulator ellipsometer that measures N, S, and C data simultaneously. The data were fit to a model consisting of air / roughness / SiN / crystalline silicon. The roughness was modeled using the Bruggeman effective medium approximation, assuming 50% SiN, 50% voids. The optical functions of the SiN film were parameterized using a model by Jellison and Modine. All the {Chi}{sup 2} are near 1, demonstrating that this model works extremely well for all SiN films. The measured dielectric functions were used to make optimized SiN antireflection coatings for crystalline silicon solar cells.

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

    DOE Patents [OSTI]

    Perkins, John; Van Hest, Marinus Franciscus Antonius Maria; Ginley, David; Taylor, Matthew; Neuman, George A.; Luten, Henry A.; Forgette, Jeffrey A.; Anderson, John S.

    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.

  4. The electron beam hole drilling of silicon nitride thin films

    SciTech Connect (OSTI)

    Howitt, D. G.; Chen, S. J.; Gierhart, B. C.; Smith, R. L.; Collins, S. D.

    2008-01-15

    The mechanism by which an intense electron beam can produce holes in thin films of silicon nitride has been investigated using a combination of in situ electron energy loss spectrometry and electron microscopy imaging. A brief review of electron beam interactions that lead to material loss in different materials is also presented. The loss of nitrogen and silicon decreases with decreasing beam energy and although still observable at a beam energy of 150 keV ceases completely at 120 keV. The linear behavior of the loss rate coupled with the energy dependency indicates that the process is primarily one of direct displacement, involving the sputtering of atoms from the back surface of the specimen with the rate controlling mechanism being the loss of nitrogen.

  5. Strongly enhanced tunable photoluminescence in polymorphous silicon carbon thin films via excitation-transfer mechanism

    SciTech Connect (OSTI)

    Wang Junzhuan; Suendo, V.; Abramov, A.; Yu Linwei; Roca i Cabarrocas, Pere

    2010-11-29

    Here, we investigate the enhanced tunable photoluminescence (PL) of hydrogenated polymorphous silicon carbon (pm-Si{sub 1-x}C{sub x}:H) thin films fabricated in a plasma enhanced chemical vapor deposition system. The silicon nanocrystal (nc-Si) inclusions are formed during gas-phase nucleation and incorporated in the hydrogenated amorphous silicon carbon (a-SiC:H) matrix. The nc-Si provides high-quality recombination centers for the photogenerated carriers in the pm-Si{sub 1-x}C{sub x}:H material, while the a-SiC:H matrix plays a role of sensitizer. We elucidate and provide experimental evidence for this excitation-transfer mechanism. Strongly enhanced PL performance can be achieved by effective matrix passivation that favors a diffusion-driven carrier recombination in the nc-Si centers.

  6. Optical limiting effects in nanostructured silicon carbide thin films

    SciTech Connect (OSTI)

    Borshch, A A; Starkov, V N; Volkov, V I; Rudenko, V I; Boyarchuk, A Yu; Semenov, A V

    2013-12-31

    We present the results of experiments on the interaction of nanosecond laser radiation at 532 and 1064 nm with nanostructured silicon carbide thin films of different polytypes. We have found the effect of optical intensity limiting at both wavelengths. The intensity of optical limiting at ? = 532 nm (I{sub cl} ? 10{sup 6} W cm{sup -2}) is shown to be an order of magnitude less than that at ? = 1064 nm (I{sub cl} ? 10{sup 7} W cm{sup -2}). We discuss the nature of the nonlinearity, leading to the optical limiting effect. We have proposed a method for determining the amount of linear and two-photon absorption in material media. (nonlinear optical phenomena)

  7. Materials and Electrical Characterization of Physical Vapor Deposited LaxLu1-xO3 Thin Films on 300 mm Silicon

    SciTech Connect (OSTI)

    L Edge; T Vo; V Paruchuri; R Iijima; J Bruley; J Jordan-Sweet; B Linder; A Kellock; T Tsunoda; S Shinde

    2011-12-31

    La{sub x}Lu{sub 1-x}O{sub 3} thin films were deposited on 300 mm silicon wafers by physical vapor deposition and fabricated into field-effect transistors using a gate-first process flow. The films were characterized using transmission electron microscopy, Rutherford backscattering spectrometry, and synchrotron x-ray diffraction. The results show the films remain amorphous even at temperatures of 1000 C. The dielectric properties of La{sub x}Lu{sub 1-x}O{sub 3} (0.125 {<=} x {<=} 0.875) thin films were evaluated as a function of film composition. The amorphous La{sub x}Lu{sub 1-x}O{sub 3} thin films have a dielectric constant (K) of 23 across the composition range. The inversion thickness (T{sub inv}) of the La{sub x}Lu{sub 1-x}O{sub 3} thin films was scaled to <1.0 nm.

  8. Record Makes Thin-Film Solar Cell Competitive with Silicon Efficiency...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Record Makes Thin-Film Solar Cell Competitive with Silicon Efficiency March 24, 2008 Researchers at the U.S. Department of Energy's National Renewable Energy Laboratory have moved ...

  9. Silicon-integrated thin-film structure for electro-optic applications

    DOE Patents [OSTI]

    McKee, Rodney A.; Walker, Frederick Joseph

    2000-01-01

    A crystalline thin-film structure suited for use in any of an number of electro-optic applications, such as a phase modulator or a component of an interferometer, includes a semiconductor substrate of silicon and a ferroelectric, optically-clear thin film of the perovskite BaTiO.sub.3 overlying the surface of the silicon substrate. The BaTiO.sub.3 thin film is characterized in that substantially all of the dipole moments associated with the ferroelectric film are arranged substantially parallel to the surface of the substrate to enhance the electro-optic qualities of the film.

  10. Progress in thin film solar photovoltaic technologies

    SciTech Connect (OSTI)

    Ullal, H.S.; Zweibel, K.

    1989-12-01

    This paper focuses on the rapid recent advances made by thin film solar cell technologies, namely, amorphous silicon, copper indium diselenide, and cadmium telluride. It also indicates the several advantages of thin films. Various consumer products and power applications using thin film solar cells are also discussed. The increasing interest among the utilities for PV system applications is also elucidated. 29 refs., 8 figs., 3 tabs.

  11. Ambipolar charge transport in microcrystalline silicon thin-film transistors

    SciTech Connect (OSTI)

    Knipp, Dietmar; Marinkovic, M.; Chan, Kah-Yoong; Gordijn, Aad; Stiebig, Helmut

    2011-01-15

    Hydrogenated microcrystalline silicon ({mu}c-Si:H) is a promising candidate for thin-film transistors (TFTs) in large-area electronics due to high electron and hole charge carrier mobilities. We report on ambipolar TFTs based on {mu}c-Si:H prepared by plasma-enhanced chemical vapor deposition at temperatures compatible with flexible substrates. Electrons and holes are directly injected into the {mu}c-Si:H channel via chromium drain and source contacts. The TFTs exhibit electron and hole charge carrier mobilities of 30-50 cm{sup 2}/V s and 10-15 cm{sup 2}/V s, respectively. In this work, the electrical characteristics of the ambipolar {mu}c-Si:H TFTs are described by a simple analytical model that takes the ambipolar charge transport into account. The analytical expressions are used to model the transfer curves, the potential and the net surface charge along the channel of the TFTs. The electrical model provides insights into the electronic transport of ambipolar {mu}c-Si:H TFTs.

  12. Project Summary of the NREL Amorphous Silicon Team

    SciTech Connect (OSTI)

    Nelson, B. P.; Branz, H. M.; Crandall, R. S.; Iwaniczko, E.; Mahan, A. H.; Stradins, P.; Wang, Q.; Xu, Y.

    2003-05-01

    The Amorphous Silicon Team at NREL has improved the properties of many materials, increased solar cell device performance, and improved the fundamental understanding of thin-film silicon based materials and devices since the last NCPV Program Review Meeting. In this paper we present a summary of the work of the team since that last meeting.

  13. Crystallization study of amorphous sputtered NiTi bi-layer thin film

    SciTech Connect (OSTI)

    Mohri, Maryam; Nili-Ahmadabadi, Mahmoud; Chakravadhanula, Venkata Sai Kiran

    2015-05-15

    The crystallization of Ni-rich/NiTiCu bi-layer thin film deposited by magnetron sputtering from two separate alloy targets was investigated. To achieve the shape memory effect, the NiTi thin films deposited at room temperature with amorphous structure were annealed at 773 K for 15, 30, and 60 min for crystallization. Characterization of the films was carried out by differential scanning calorimetry to indicate the crystallization temperature, grazing incidence X-ray diffraction to identify the phase structures, atomic force microscopy to evaluate surface morphology, scanning transmission electron microscopy to study the cross section of the thin films. The results show that the structure of the annealed thin films strongly depends on the temperature and time of the annealing. Crystalline grains nucleated first at the surface and then grew inward to form columnar grains. Furthermore, the crystallization behavior was markedly affected by composition variations. - Highlights: • A developed bi-layer Ni45TiCu5/Ni50.8Ti was deposited on Si substrate and crystallized. • During crystallization, The Ni{sub 45}TiCu{sub 5} layer is thermally less stable than the Ni-rich layer. • The activation energy is 302 and 464 kJ/mol for Cu-rich and Ni-rich layer in bi-layer, respectively.

  14. Sequential lateral solidification of silicon thin films on low-k dielectrics for low temperature integration

    SciTech Connect (OSTI)

    Carta, Fabio Hlaing, Htay; Kymissis, Ioannis; Gates, Stephen M.; Edelstein, Daniel C.; Limanov, Alexander B.; Im, James S.

    2014-12-15

    We present the excimer laser crystallization of amorphous silicon on a low dielectric constant (low-k) insulator for very large scale integration monolithic 3D integration and demonstrate that low dielectric constant materials are suitable substrates for 3D integration through laser crystallization of silicon thin films. We crystallized 100 nm amorphous silicon on top of SiO{sub 2} and SiCOH (low-k) dielectrics, at different material thicknesses (1 μm, 0.75 μm, and 0.5 μm). The amorphous silicon crystallization on low-k dielectric requires 35% less laser energy than on an SiO{sub 2} dielectric. This difference is related to the thermal conductivity of the two materials, in agreement with one dimensional simulations of the crystallization process. We analyzed the morphology of the material through defect-enhanced microscopy, Raman spectroscopy, and X-ray diffraction analysis. SEM micrographs show that polycrystalline silicon is characterized by micron-long grains with an average width of 543 nm for the SiO{sub 2} sample and 570 nm for the low-k samples. Comparison of the Raman spectra does not show any major difference in film quality for the two different dielectrics, and polycrystalline silicon peaks are closely placed around 517 cm{sup −1}. From X-ray diffraction analysis, the material crystallized on SiO{sub 2} shows a preferential (111) crystal orientation. In the SiCOH case, the 111 peak strength decreases dramatically and samples do not show preferential crystal orientation. A 1D finite element method simulation of the crystallization process on a back end of line structure shows that copper (Cu) damascene interconnects reach a temperature of 70 °C or lower with a 0.5 μm dielectric layer between the Cu and the molten Si layer, a favorable condition for monolithic 3D integration.

  15. Tunable giant magnetic anisotropy in amorphous SmCo thin films

    SciTech Connect (OSTI)

    Magnus, F.; Moubah, R.; Roos, A. H.; Kapaklis, V.; Hjoervarsson, B.; Andersson, G.; Kruk, A.; Hase, T.

    2013-04-22

    SmCo thin films have been grown by magnetron sputtering at room temperature with a composition of 2-35 at. % Sm. Films with 5 at. % or higher Sm are amorphous and smooth. A giant tunable uniaxial in-plane magnetic anisotropy is induced in the films which peaks in the composition range 11-22 at. % Sm. This cross-over behavior is not due to changes in the atomic moments but rather the local configuration changes. The excellent layer perfection combined with highly tunable magnetic properties make these films important for spintronics applications.

  16. Effect of medium range order on pulsed laser crystallization of amorphous germanium thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, T. T.; Bayu Aji, L. B.; Heo, T. W.; Santala, M. K.; Kucheyev, S. O.; Campbell, G. H.

    2016-06-03

    Sputter deposited amorphous Ge thin films had their nanostructure altered by irradiation with high-energy Ar+ ions. The change in the structure resulted in a reduction in medium range order (MRO) characterized using fluctuation electron microscopy. The pulsed laser crystallization kinetics of the as-deposited versus irradiated materials were investigated using the dynamic transmission electron microscope operated in the multi-frame movie mode. In conclusion, the propagation rate of the crystallization front for the irradiated material was lower; the changes were correlated to the MRO difference and formation of a thin liquid layer during crystallization.

  17. Nitrogen effects on crystallization kinetics of amorphous TiOxNy thin films

    SciTech Connect (OSTI)

    Hukari, Kyle; Dannenberg, Rand; Stach, E.A.

    2001-03-30

    The crystallization behavior of amorphous TiOxNy (x>>y) thin films was investigated by in-situ transmission electron microscopy. The Johnson-Mehl-Avrami-Kozolog (JMAK) theory is used to determine the Avrami exponent, activation energy, and the phase velocity pre-exponent. Addition of nitrogen inhibits diffusion, increasing the nucleation temperature, while decreasing the growth activation energy. Kinetic variables extracted from individual crystallites are compared to JMAK analysis of the fraction transformed and a change of 6 percent in the activation energy gives agreement between the methods. From diffraction patterns and index of refraction the crystallized phase was found to be predominantly anatase.

  18. NREL: Photovoltaics Research - Thin Film Photovoltaic Partnership Project

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Thin Film Photovoltaic Partnership Project NREL's Thin Film Photovoltaic (PV) Partnership Project led R&D on emerging thin-film solar technologies in the United States from 1994 to 2009. The project made many advances in thin-film PV technologies that allowed the United States to attain world leadership in this area of solar technology. Three national R&D teams focused on thin-film semiconductor materials: amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium

  19. Overview and Challenges of Thin Film Solar Electric Technologies

    SciTech Connect (OSTI)

    Ullal, H. S.

    2008-12-01

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

  20. Demonstration of thin film pair distribution function analysis (tfPDF) for the study of local structure in amorphous and crystalline thin films

    SciTech Connect (OSTI)

    Jensen, K. M.Ø.; Blichfeld, A. B.; Bauers, S. R.; Wood, S. R.; Dooryhee, E.; Johnson, D. C.; Iversen, B. B.; Billinge, S.

    2015-07-05

    By means of normal incidence, high flux and high energy x-rays, we have obtained total scattering data for Pair Distribution Function (PDF) analysis from thin films (tf), suitable for local structure analysis. By using amorphous substrates as support for the films, the standard Rapid Acquisition PDF setup can be applied and the scattering signal from the film can be isolated from the total scattering data through subtraction of an independently measured background signal. No angular corrections to the data are needed, as would be the case for grazing incidence measurements. We illustrate the ‘tfPDF’ method through studies of as deposited (i.e. amorphous) and crystalline FeSb3 films, where the local structure analysis gives insight into the stabilization of the metastable skutterudite FeSb3 phase. The films were prepared by depositing ultra-thin alternating layers of Fe and Sb, which interdiffuse and after annealing crystallize to form the FeSb3 structure. The tfPDF data show that the amorphous precursor phase consists of corner-sharing FeSb6 octahedra with motifs highly resembling the local structure in crystalline FeSb3. Analysis of the amorphous structure allows predicting whether the final crystalline product will form the FeSb3 phase with or without excess Sb present. The study thus illustrates how analysis of the local structure in amorphous precursor films can help to understand crystallization processes of metastable phases and opens for a range of new local structure studies of thin films.

  1. Demonstration of thin film pair distribution function analysis (tfPDF) for the study of local structure in amorphous and crystalline thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Jensen, K. M.Ø.; Blichfeld, A. B.; Bauers, S. R.; Wood, S. R.; Dooryhee, E.; Johnson, D. C.; Iversen, B. B.; Billinge, S.

    2015-07-05

    By means of normal incidence, high flux and high energy x-rays, we have obtained total scattering data for Pair Distribution Function (PDF) analysis from thin films (tf), suitable for local structure analysis. By using amorphous substrates as support for the films, the standard Rapid Acquisition PDF setup can be applied and the scattering signal from the film can be isolated from the total scattering data through subtraction of an independently measured background signal. No angular corrections to the data are needed, as would be the case for grazing incidence measurements. We illustrate the ‘tfPDF’ method through studies of as depositedmore » (i.e. amorphous) and crystalline FeSb3 films, where the local structure analysis gives insight into the stabilization of the metastable skutterudite FeSb3 phase. The films were prepared by depositing ultra-thin alternating layers of Fe and Sb, which interdiffuse and after annealing crystallize to form the FeSb3 structure. The tfPDF data show that the amorphous precursor phase consists of corner-sharing FeSb6 octahedra with motifs highly resembling the local structure in crystalline FeSb3. Analysis of the amorphous structure allows predicting whether the final crystalline product will form the FeSb3 phase with or without excess Sb present. The study thus illustrates how analysis of the local structure in amorphous precursor films can help to understand crystallization processes of metastable phases and opens for a range of new local structure studies of thin films.« less

  2. Hydrogen passivation of electron trap in amorphous In-Ga-Zn-O thin-film transistors

    SciTech Connect (OSTI)

    Hanyu, Yuichiro Domen, Kay; Nomura, Kenji; Hiramatsu, Hidenori; Kamiya, Toshio; Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama ; Kumomi, Hideya; Hosono, Hideo; Frontier Research Center, Tokyo Institute of Technology, Yokohama; Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama

    2013-11-11

    We report an experimental evidence that some hydrogens passivate electron traps in an amorphous oxide semiconductor, a-In-Ga-Zn-O (a-IGZO). The a-IGZO thin-film transistors (TFTs) annealed at 300?C exhibit good operation characteristics; while those annealed at ?400?C show deteriorated ones. Thermal desorption spectra (TDS) of H{sub 2}O indicate that this threshold annealing temperature corresponds to depletion of H{sub 2}O desorption from the a-IGZO layer. Hydrogen re-doping by wet oxygen annealing recovers the good TFT characteristic. The hydrogens responsible for this passivation have specific binding energies corresponding to the desorption temperatures of 300430?C. A plausible structural model is suggested.

  3. Process For Direct Integration Of A Thin-Film Silicon P-N Junction Diode With A Magnetic Tunnel Junction

    DOE Patents [OSTI]

    Toet, Daniel; Sigmon, Thomas W.

    2005-08-23

    A process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction for use in advanced magnetic random access memory (MRAM) cells for high performance, non-volatile memory arrays. The process is based on pulsed laser processing for the fabrication of vertical polycrystalline silicon electronic device structures, in particular p-n junction diodes, on films of metals deposited onto low temperature-substrates such as ceramics, dielectrics, glass, or polymers. The process preserves underlayers and structures onto which the devices are typically deposited, such as silicon integrated circuits. The process involves the low temperature deposition of at least one layer of silicon, either in an amorphous or a polycrystalline phase on a metal layer. Dopants may be introduced in the silicon film during or after deposition. The film is then irradiated with short pulse laser energy that is efficiently absorbed in the silicon, which results in the crystallization of the film and simultaneously in the activation of the dopants via ultrafast melting and solidification. The silicon film can be patterned either before or after crystallization.

  4. Process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction

    DOE Patents [OSTI]

    Toet, Daniel; Sigmon, Thomas W.

    2003-01-01

    A process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction for use in advanced magnetic random access memory (MRAM) cells for high performance, non-volatile memory arrays. The process is based on pulsed laser processing for the fabrication of vertical polycrystalline silicon electronic device structures, in particular p-n junction diodes, on films of metals deposited onto low temperature-substrates such as ceramics, dielectrics, glass, or polymers. The process preserves underlayers and structures onto which the devices are typically deposited, such as silicon integrated circuits. The process involves the low temperature deposition of at least one layer of silicon, either in an amorphous or a polycrystalline phase on a metal layer. Dopants may be introduced in the silicon film during or after deposition. The film is then irradiated with short pulse laser energy that is efficiently absorbed in the silicon, which results in the crystallization of the film and simultaneously in the activation of the dopants via ultrafast melting and solidification. The silicon film can be patterned either before or after crystallization.

  5. Process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction

    DOE Patents [OSTI]

    Toet, Daniel; Sigmon, Thomas W.

    2004-12-07

    A process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction for use in advanced magnetic random access memory (MRAM) cells for high performance, non-volatile memory arrays. The process is based on pulsed laser processing for the fabrication of vertical polycrystalline silicon electronic device structures, in particular p-n junction diodes, on films of metals deposited onto low temperature-substrates such as ceramics, dielectrics, glass, or polymers. The process preserves underlayers and structures onto which the devices are typically deposited, such as silicon integrated circuits. The process involves the low temperature deposition of at least one layer of silicon, either in an amorphous or a polycrystalline phase on a metal layer. Dopants may be introduced in the silicon film during or after deposition. The film is then irradiated with short pulse laser energy that is efficiently absorbed in the silicon, which results in the crystallization of the film and simultaneously in the activation of the dopants via ultrafast melting and solidification. The silicon film can be patterned either before or after crystallization.

  6. Advances in amorphous silicon photovoltaic technology

    SciTech Connect (OSTI)

    Carlson, D.E.; Rajan, K.; Arya, R.R.; Willing, F.; Yang, L.

    1998-10-01

    With the advent of new multijunction thin film solar cells, amorphous silicon photovoltaic technology is undergoing a commercial revival with about 30 megawatts of annual capacity coming on-line in the next year. These new {ital a}{endash}Si multijunction modules should exhibit stabilized conversion efficiencies on the order of 8{percent}, and efficiencies over 10{percent} may be obtained in the next several years. The improved performance results from the development of amorphous and microcrystalline silicon alloy films with improved optoelectronic properties and from the development of more efficient device structures. Moreover, the manufacturing costs for these multijunction modules using the new large-scale plants should be on the order of {dollar_sign}1 per peak watt. These new modules may find widespread use in solar farms, photovoltaic roofing, as well as in traditional remote applications. {copyright} {ital 1998 Materials Research Society.}

  7. Method of fabrication of display pixels driven by silicon thin film transistors

    DOE Patents [OSTI]

    Carey, Paul G.; Smith, Patrick M.

    1999-01-01

    Display pixels driven by silicon thin film transistors are fabricated on plastic substrates for use in active matrix displays, such as flat panel displays. The process for forming the pixels involves a prior method for forming individual silicon thin film transistors on low-temperature plastic substrates. Low-temperature substrates are generally considered as being incapable of withstanding sustained processing temperatures greater than about 200.degree. C. The pixel formation process results in a complete pixel and active matrix pixel array. A pixel (or picture element) in an active matrix display consists of a silicon thin film transistor (TFT) and a large electrode, which may control a liquid crystal light valve, an emissive material (such as a light emitting diode or LED), or some other light emitting or attenuating material. The pixels can be connected in arrays wherein rows of pixels contain common gate electrodes and columns of pixels contain common drain electrodes. The source electrode of each pixel TFT is connected to its pixel electrode, and is electrically isolated from every other circuit element in the pixel array.

  8. The future of amorphous silicon photovoltaic technology

    SciTech Connect (OSTI)

    Crandall, R; Luft, W

    1995-06-01

    Amorphous silicon modules are commercially available. They are the first truly commercial thin-film photovoltaic (PV) devices. Well-defined production processes over very large areas (>1 m{sup 2}) have been implemented. There are few environmental issues during manufacturing, deployment in the field, or with the eventual disposal of the modules. Manufacturing safety issues are well characterized and controllable. The highest measured initial efficiency to date is 13.7% for a small triple-stacked cell and the highest stabilized module efficiency is 10%. There is a consensus among researchers, that in order to achieve a 15% stabilized efficiency, a triple-junction amorphous silicon structure is required. Fundamental improvements in alloys are needed for higher efficiencies. This is being pursued through the DOE/NREL Thin-Film Partnership Program. Cost reductions through improved manufacturing processes are being pursued under the National Renewable Energy Laboratory/US Department of Energy (NREL/DOE)-sponsored research in manufacturing technology (PVMaT). Much of the work in designing a-Si devices is a result of trying to compensate for the Staebler-Wronski effect. Some new deposition techniques hold promise because they have produced materials with lower stabilized defect densities. However, none has yet produced a high efficiency device and shown it to be more stable than those from standard glow discharge deposited material.

  9. Near-field radiative heat transfer between metamaterials coated with silicon carbide thin films

    SciTech Connect (OSTI)

    Basu, Soumyadipta Yang, Yue; Wang, Liping

    2015-01-19

    In this letter, we study the near-field radiative heat transfer between two metamaterial substrates coated with silicon carbide (SiC) thin films. It is known that metamaterials can enhance the near-field heat transfer over ordinary materials due to excitation of magnetic plasmons associated with s polarization, while strong surface phonon polariton exists for SiC. By careful tuning of the optical properties of metamaterial, it is possible to excite electrical and magnetic resonances for the metamaterial and surface phonon polaritons for SiC at different spectral regions, resulting in the enhanced heat transfer. The effect of the SiC film thickness at different vacuum gaps is investigated. Results obtained from this study will be beneficial for application of thin film coatings for energy harvesting.

  10. PEDOT:PSS emitters on multicrystalline silicon thin-film absorbers for hybrid solar cells

    SciTech Connect (OSTI)

    Junghanns, Marcus; Plentz, Jonathan Andrä, Gudrun; Gawlik, Annett; Höger, Ingmar; Falk, Fritz

    2015-02-23

    We fabricated an efficient hybrid solar cell by spin coating poly(3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS) on planar multicrystalline Si (mc-Si) thin films. The only 5 μm thin Si absorber layers were prepared by diode laser crystallization of amorphous Si deposited by electron beam evaporation on glass. On these absorber layers, we studied the effect of SiO{sub x} and Al{sub 2}O{sub 3} terminated Si surfaces. The short circuit density and power conversion efficiency (PCE) of the mc-Si/Al{sub 2}O{sub 3}/PEDOT:PSS solar cell increase from 20.6 to 25.4 mA/cm{sup 2} and from 7.3% to 10.3%, respectively, as compared to the mc-Si/SiO{sub x}/PEDOT:PSS cell. Al{sub 2}O{sub 3} lowers the interface recombination and improves the adhesion of the polymer film on the hydrophobic mc-Si thin film. Open circuit voltages up to 604 mV were reached. This study demonstrates the highest PCE so far of a hybrid solar cell with a planar thin film Si absorber.

  11. Amorphous silicon photovoltaic devices

    DOE Patents [OSTI]

    Carlson, David E.; Lin, Guang H.; Ganguly, Gautam

    2004-08-31

    This invention is a photovoltaic device comprising an intrinsic or i-layer of amorphous silicon and where the photovoltaic device is more efficient at converting light energy to electric energy at high operating temperatures than at low operating temperatures. The photovoltaic devices of this invention are suitable for use in high temperature operating environments.

  12. Properties of boron-doped thin films of polycrystalline silicon

    SciTech Connect (OSTI)

    Merabet, Souad

    2013-12-16

    The properties of polycrystalline-silicon films deposited by low pressure chemical vapor deposition and doped heavily in situ boron-doped with concentration level of around 2×10{sup 20}cm{sup −3} has been studied. Their properties are analyzed using electrical and structural characterization means by four points probe resistivity measurements and X-ray diffraction spectra. The thermal-oxidation process are performed on sub-micron layers of 200nm/c-Si and 200nm/SiO{sub 2} deposited at temperatures T{sub d} ranged between 520°C and 605°C and thermally-oxidized in dry oxygen ambient at 945°C. Compared to the as-grown resistivity with silicon wafers is known to be in the following sequence <ρ{sub 200nm/c−Si}> < <ρ{sub 200nm/SiO2}> and <ρ{sub 520}> < <ρ{sub 605}>. The measure X-ray spectra is shown, that the Bragg peaks are marked according to the crystal orientation in the film deposited on bare substrates (poly/c-Si), for the second series of films deposited on bare oxidized substrates (poly/SiO{sub 2}) are clearly different.

  13. Amorphous silicon radiation detectors

    DOE Patents [OSTI]

    Street, R.A.; Perez-Mendez, V.; Kaplan, S.N.

    1992-11-17

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification. 13 figs.

  14. Amorphous silicon radiation detectors

    DOE Patents [OSTI]

    Street, Robert A.; Perez-Mendez, Victor; Kaplan, Selig N.

    1992-01-01

    Hydrogenated amorphous silicon radiation detector devices having enhanced signal are disclosed. Specifically provided are transversely oriented electrode layers and layered detector configurations of amorphous silicon, the structure of which allow high electric fields upon application of a bias thereby beneficially resulting in a reduction in noise from contact injection and an increase in signal including avalanche multiplication and gain of the signal produced by incoming high energy radiation. These enhanced radiation sensitive devices can be used as measuring and detection means for visible light, low energy photons and high energy ionizing particles such as electrons, x-rays, alpha particles, beta particles and gamma radiation. Particular utility of the device is disclosed for precision powder crystallography and biological identification.

  15. Effects of ion energy on the crystal size and hydrogen bonding in plasma-deposited nanocrystalline silicon thin films

    SciTech Connect (OSTI)

    Lebib, S.; Roca i Cabarrocas, P.

    2005-05-15

    We present a detailed study of the effects of the substrate temperature, radio-frequency (rf) power, and total pressure on the crystal size and hydrogen bonding in nanocrystalline silicon thin films codeposited on the grounded and rf electrodes of an asymmetric radio frequency glow discharge reactor. Raman spectroscopy, x-ray diffraction, and spectroscopic ellipsometry measurements show that by varying the deposition parameters we can obtain crystal sizes in the range of 3-10 nm and crystalline fractions in the range of 20% up to 97%. The obtaining of small crystallite sizes (4-5 nm) in films submitted to high-energy (100-300 eV) ion bombardment is highlighted by infrared-absorption and hydrogen evolution measurements, which display characteristic features of hydrogen bonded at the surface of the crystallites. Therefore, hydrogen bonding is a unique way to demonstrate the presence of small crystallites in films at the transition between amorphous and nanocrystalline, films which look amorphous when characterized by standard techniques such as Raman spectroscopy and x-ray diffraction.

  16. Development of Thin Film Silicon Solar Cell Using Inkjet Printed Silicon and Other Inkjet Processes: Cooperative Research and Development Final Report, CRADA Number CRD-07-260

    SciTech Connect (OSTI)

    Sopori, B.

    2012-04-01

    The cost of silicon photovoltaics (Si-PV) can be greatly lowered by developing thin-film crystalline Si solar cells on glass or an equally lower cost substrate. Typically, Si film is deposited by thermal evaporation, plasma enhanced chemical vapor deposition, and sputtering. NREL and Silexos have worked under a CRADA to develop technology to make very low cost solar cells using liquid organic precursors. Typically, cyclopentasilane (CPS) is deposited on a glass substrate and then converted into an a-Si film by UV polymerization followed by low-temperature optical process that crystallizes the amorphous layer. This technique promises to be a very low cost approach for making a Si film.

  17. Microscopic silicon-based lateral high-aspect-ratio structures for thin film conformality analysis

    SciTech Connect (OSTI)

    Gao, Feng; Arpiainen, Sanna; Puurunen, Riikka L.

    2015-01-15

    Film conformality is one of the major drivers for the interest in atomic layer deposition (ALD) processes. This work presents new silicon-based microscopic lateral high-aspect-ratio (LHAR) test structures for the analysis of the conformality of thin films deposited by ALD and by other chemical vapor deposition means. The microscopic LHAR structures consist of a lateral cavity inside silicon with a roof supported by pillars. The cavity length (e.g., 20–5000 μm) and cavity height (e.g., 200–1000 nm) can be varied, giving aspect ratios of, e.g., 20:1 to 25 000:1. Film conformality can be analyzed with the microscopic LHAR by several means, as demonstrated for the ALD Al{sub 2}O{sub 3} and TiO{sub 2} processes from Me{sub 3}Al/H{sub 2}O and TiCl{sub 4}/H{sub 2}O. The microscopic LHAR test structures introduced in this work expose a new parameter space for thin film conformality investigations expected to prove useful in the development, tuning and modeling of ALD and other chemical vapor deposition processes.

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

    SciTech Connect (OSTI)

    Kesim, M. T.; Zhang, J.; Alpay, S. P.; Trolier-McKinstry, S.; Mantese, J. V.; Whatmore, R. W.

    2013-11-28

    Ferroelectric lead zirconate titanate [Pb(Zr{sub x}Ti{sub 1-x}O){sub 3}, (PZT x:1-x)] has received considerable interest for applications related to uncooled infrared devices due to its large pyroelectric figures of merit near room temperature, and the fact that such devices are inherently ac coupled, allowing for simplified image post processing. For ferroelectric films made by industry-standard deposition techniques, stresses develop in the PZT layer upon cooling from the processing/growth temperature due to thermal mismatch between the film and the substrate. In this study, we use a non-linear thermodynamic model to investigate the pyroelectric properties of polycrystalline PZT thin films for five different compositions (PZT 40:60, PZT 30:70, PZT 20:80, PZT 10:90, PZT 0:100) on silicon as a function of processing temperature (25800?C). It is shown that the in-plane thermal stresses in PZT thin films alter the out-of-plane polarization and the ferroelectric phase transformation temperature, with profound effect on the pyroelectric properties. PZT 30:70 is found to have the largest pyroelectric coefficient (0.042??C cm{sup ?2}?C{sup ?1}, comparable to bulk values) at a growth temperature of 550?C; typical to what is currently used for many deposition processes. Our results indicate that it is possible to optimize the pyroelectric response of PZT thin films by adjusting the Ti composition and the processing temperature, thereby, enabling the tailoring of material properties for optimization relative to a specific deposition process.

  19. Thin film polycrystalline silicon: Promise and problems in displays and solar cells

    SciTech Connect (OSTI)

    Fonash, S.J.

    1995-08-01

    Thin film polycrystalline Si (poly-Si) with its carrier mobilities, potentially good stability, low intragrain defect density, compatibility with silicon processing, and ease of doping activation is an interesting material for {open_quotes}macroelectronics{close_quotes} applications such as TFTs for displays and solar cells. The poly-Si films needed for these applications can be ultra-thin-in the 500{Angstrom} to 1000{Angstrom} thickness range for flat panel display TFTs and in the 4{mu}m to 10{mu}m thickness range for solar cells. Because the films needed for these microelectronics applications can be so thin, an effective approach to producing the films is that of crystallizing a-Si precursor material. Unlike cast materials, poly-Si films made this way can be produced using low temperature processing. Unlike deposited poly-Si films, these crystallized poly-Si films can have grain widths that are much larger than the film thickness and almost atomically smooth surfaces. This thin film poly-Si crystallized from a-Si precursor films, and its promise and problems for TFTs and solar cells, is the focus of this discussion.

  20. Synthesis and characterization of large-grain solid-phase crystallized polycrystalline silicon thin films

    SciTech Connect (OSTI)

    Kumar, Avishek, E-mail: avishek.kumar@nus.edu.sg, E-mail: dalapatig@imre.a-star.edu.sg [Solar Energy Research Institute of Singapore, National University of Singapore, 7 Engineering Drive 1, Block E3A, #06-01, Singapore 117574 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore); Law, Felix; Widenborg, Per I. [Solar Energy Research Institute of Singapore, National University of Singapore, 7 Engineering Drive 1, Block E3A, #06-01, Singapore 117574 (Singapore); Dalapati, Goutam K., E-mail: avishek.kumar@nus.edu.sg, E-mail: dalapatig@imre.a-star.edu.sg; Subramanian, Gomathy S.; Tan, Hui R. [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore); Aberle, Armin G. [Solar Energy Research Institute of Singapore, National University of Singapore, 7 Engineering Drive 1, Block E3A, #06-01, Singapore 117574 and Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore)

    2014-11-01

    n-type polycrystalline silicon (poly-Si) films with very large grains, exceeding 30??m in width, and with high Hall mobility of about 71.5?cm{sup 2}/V s are successfully prepared by the solid-phase crystallization technique on glass through the control of the PH{sub 3} (2% in H{sub 2})/SiH{sub 4} gas flow ratio. The effect of this gas flow ratio on the electronic and structural quality of the n-type poly-Si thin film is systematically investigated using Hall effect measurements, Raman microscopy, and electron backscatter diffraction (EBSD), respectively. The poly-Si grains are found to be randomly oriented, whereby the average area weighted grain size is found to increase from 4.3 to 18??m with increase of the PH{sub 3} (2% in H{sub 2})/SiH{sub 4} gas flow ratio. The stress in the poly-Si thin films is found to increase above 900?MPa when the PH{sub 3} (2% in H{sub 2})/SiH{sub 4} gas flow ratio is increased from 0.025 to 0.45. Finally, high-resolution transmission electron microscopy, high angle annular dark field-scanning tunneling microscopy, and EBSD are used to identify the defects and dislocations caused by the stress in the fabricated poly-Si films.

  1. Solution-processed amorphous silicon surface passivation layers

    SciTech Connect (OSTI)

    Mews, Mathias Sontheimer, Tobias; Korte, Lars; Rech, Bernd; Mader, Christoph; Traut, Stephan; Wunnicke, Odo

    2014-09-22

    Amorphous silicon thin films, fabricated by thermal conversion of neopentasilane, were used to passivate crystalline silicon surfaces. The conversion is investigated using X-ray and constant-final-state-yield photoelectron spectroscopy, and minority charge carrier lifetime spectroscopy. Liquid processed amorphous silicon exhibits high Urbach energies from 90 to 120?meV and 200?meV lower optical band gaps than material prepared by plasma enhanced chemical vapor deposition. Applying a hydrogen plasma treatment, a minority charge carrier lifetime of 1.37?ms at an injection level of 10{sup 15}/cm{sup 3} enabling an implied open circuit voltage of 724?mV was achieved, demonstrating excellent silicon surface passivation.

  2. Compensated amorphous silicon solar cell

    DOE Patents [OSTI]

    Carlson, David E.

    1980-01-01

    An amorphous silicon solar cell incorporates a region of intrinsic hydrogenated amorphous silicon fabricated by a glow discharge wherein said intrinsic region is compensated by P-type dopants in an amount sufficient to reduce the space charge density of said region under illumination to about zero.

  3. Compensated amorphous silicon solar cell

    DOE Patents [OSTI]

    Devaud, Genevieve

    1983-01-01

    An amorphous silicon solar cell including an electrically conductive substrate, a layer of glow discharge deposited hydrogenated amorphous silicon over said substrate and having regions of differing conductivity with at least one region of intrinsic hydrogenated amorphous silicon. The layer of hydrogenated amorphous silicon has opposed first and second major surfaces where the first major surface contacts the electrically conductive substrate and an electrode for electrically contacting the second major surface. The intrinsic hydrogenated amorphous silicon region is deposited in a glow discharge with an atmosphere which includes not less than about 0.02 atom percent mono-atomic boron. An improved N.I.P. solar cell is disclosed using a BF.sub.3 doped intrinsic layer.

  4. The state of the art of thin-film photovoltaics

    SciTech Connect (OSTI)

    Surek, T.

    1993-10-01

    Thin-film photovoltaic technologies, based on materials such as amorphous or polycrystalline silicon, copper indium diselenide, cadmium telluride, and gallium arsenide, offer the potential for significantly reducing the cost of electricity generated by photovoltaics. The significant progress in the technologies, from the laboratory to the marketplace, is reviewed. The common concerns and questions raised about thin films are addressed. Based on the progress to date and the potential of these technologies, along with continuing investments by the private sector to commercialize the technologies, one can conclude that thin-film PV will provide a competitive alternative for large-scale power generation in the future.

  5. Surface smoothing effect of an amorphous thin film deposited by atomic layer deposition on a surface with nano-sized roughness

    SciTech Connect (OSTI)

    Lau, W. S. Wan, X.; Xu, Y.; Wong, H.; Zhang, J.; Luo, J. K.; Institute of Renewable Energy and Environment Technology, Bolton University, Deane Road, Bolton BL3 5 AB

    2014-02-15

    Previously, Lau (one of the authors) pointed out that the deposition of an amorphous thin film by atomic layer deposition (ALD) on a substrate with nano-sized roughness probably has a surface smoothing effect. In this letter, polycrystalline zinc oxide deposited by ALD onto a smooth substrate was used as a substrate with nano-sized roughness. Atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (XTEM) were used to demonstrate that an amorphous aluminum oxide thin film deposited by ALD can reduce the surface roughness of a polycrystalline zinc oxide coated substrate.

  6. Optimal design of one-dimensional photonic crystal back reflectors for thin-film silicon solar cells

    SciTech Connect (OSTI)

    Chen, Peizhuan; Hou, Guofu Zhang, Jianjun Zhang, Xiaodan; Zhao, Ying

    2014-08-14

    For thin-film silicon solar cells (TFSC), a one-dimensional photonic crystal (1D PC) is a good back reflector (BR) because it increases the total internal reflection at the back surface. We used the plane-wave expansion method and the finite difference time domain (FDTD) algorithm to simulate and analyze the photonic bandgap (PBG), the reflection and the absorption properties of a 1D PC and to further explore the optimal 1D PC design for use in hydrogenated amorphous silicon (a-Si:H) solar cells. With identified refractive index contrast and period thickness, we found that the PBG and the reflection of a 1D PC are strongly influenced by the contrast in bilayer thickness. Additionally, light coupled to the top three periods of the 1D PC and was absorbed if one of the bilayers was absorptive. By decreasing the thickness contrast of the absorptive layer relative to the non-absorptive layer, an average reflectivity of 96.7% was achieved for a 1D PC alternatively stacked with a-Si:H and SiO{sub 2} in five periods. This reflectivity was superior to a distributed Bragg reflector (DBR) structure with 93.5% and an Ag film with 93.4%. n-i-p a-Si:H solar cells with an optimal 1D PC-based BR offer a higher short-circuit current density than those with a DBR-based BR or an AZO/Ag-based BR. These results provide new design rules for photonic structures in TFSC.

  7. Photoelectron emission yield experiments on evolution of sub-gap states in amorphous In-Ga-Zn-O thin films with post deposition hydrogen treatment

    SciTech Connect (OSTI)

    Hayashi, Kazushi Hino, Aya; Tao, Hiroaki; Ochi, Mototaka; Goto, Hiroshi; Kugimiya, Toshihiro

    2015-09-14

    Total photoyield emission spectroscopy (TPYS) was applied to study the evolution of sub-gap states in hydrogen-treated amorphous In-Ga-Zn-O (a-IGZO) thin films. The a-IGZO thin films were subjected to hydrogen radicals and subsequently annealed in ultra-high vacuum (UHV) conditions. A clear onset of the electron emission was observed at around 4.3 eV from the hydrogen-treated a-IGZO thin films. After successive UHV annealing at 300 °C, the onset in the TPYS spectra was shifted to 4.15 eV, and the photoelectron emission from the sub-gap states was decreased as the annealing temperature was increased. In conjunction with the results of thermal desorption spectrometer, it was deduced that the hydrogen atoms incorporated in the a-IGZO thin films induced metastable sub-gap states at around 4.3 eV from vacuum level just after the hydrogenation. It was also suggested that the defect configuration was changed due to the higher temperature UHV annealing, and that the hydrogen atoms desorbed with the involvement of Zn atoms. These experiments produced direct evidence to show the formation of sub-gap states as a result of hydrogen incorporation into the a-IGZO thin films.

  8. Cathodic cage plasma deposition of TiN and TiO{sub 2} thin films on silicon substrates

    SciTech Connect (OSTI)

    Sousa, Romulo R. M. de; Sato, Patricia S.; Nascente, Pedro A. P.; Viana, Bartolomeu C.; Alves, Clodomiro; Nishimoto, Akio

    2015-07-15

    Cathodic cage plasma deposition (CCPD) was used for growing titanium nitride (TiN) and titanium dioxide (TiO{sub 2}) thin films on silicon substrates. The main advantages of the CCPD technique are the uniformity, tridimensionality, and high rate of the film deposition that occurs at higher pressures, lower temperatures, and lower treatment times than those used in conventional nitriding treatments. In this work, the influence of the temperature and gas atmosphere upon the characteristics of the deposited films was investigated. The TiN and TiO{sub 2} thin films were characterized by x-ray diffraction, scanning electron microscopy, and Raman spectroscopy to analyze their chemical, structural, and morphological characteristics, and the combination of these results indicates that the low-cost CCPD technique can be used to produce even and highly crystalline TiN and TiO{sub 2} films.

  9. Cermet layer for amorphous silicon solar cells

    DOE Patents [OSTI]

    Hanak, Joseph J.

    1979-01-01

    A transparent high work function metal cermet forms a Schottky barrier in a Schottky barrier amorphous silicon solar cell and adheres well to the P+ layer in a PIN amorphous silicon solar cell.

  10. Optical properties of amorphous and crystalline Sb-doped SnO{sub 2} thin films studied with spectroscopic ellipsometry: Optical gap energy and effective mass

    SciTech Connect (OSTI)

    So, Hyeon Seob; Park, Jun-Woo; Jung, Dae Ho; Ko, Kun Hee; Lee, Hosun

    2015-08-28

    We investigated the optical properties of amorphous and crystalline antimony (Sb)-doped tin dioxide (SnO{sub 2}) thin films grown using the co-sputtering deposition method at room temperature. We used undoped and Sb-doped (8 wt. %) SnO{sub 2} targets. Varying the relative power ratio of the two targets, we controlled the Sb-composition of the SnO{sub 2}:Sb thin films up to 2.3 at. % of Sb contents. Through annealing, the as-grown amorphous SnO{sub 2}:Sb thin films were transformed to crystalline thin films. Dielectric functions were obtained from the measured ellipsometry angles, Ψ and Δ, using the Drude and parametric optical constant models. We determined the absorption coefficients and optical gap energies of the SnO{sub 2}:Sb thin films from the dielectric functions. We found increasing optical gap energy with increasing Sb composition. Increases in the Drude tail amplitudes, a signature of free carrier concentrations, were found in annealed, crystalline thin films with increasing Sb composition. The increase in the optical gap energy with increasing Sb composition was mainly attributed to the Burstein-Moss effect. Using Hall effect measurements, we obtained Hall carrier concentrations (N{sub Hall}) and electron Hall mobilities (μ{sub Hall}). The carrier concentrations and mobilities increased from 2.6 × 10{sup 19 }cm{sup −3} and 1.0 cm{sup 2}/(V s) to 2.0 × 10{sup 20 }cm{sup −1} and 7.2 cm{sup 2}/(V s), respectively, with increasing Sb contents. This result suggests that the nominally undoped SnO{sub 2} films are unintentionally n-type doped. Assuming that the N{sub Hall} and optical carrier concentrations (N{sub opt}) were the same, we obtained the effective masses of the SnO{sub 2}:Sb thin films with increasing Sb compositions. The effective masses of the SnO{sub 2}:Sb thin films increased from 0.245 m{sub 0} to 0.4 m{sub 0} with increasing Sb doping contents, and the nonparabolicity of the conduction band was estimated. We

  11. Tandem junction amorphous silicon solar cells

    DOE Patents [OSTI]

    Hanak, Joseph J.

    1981-01-01

    An amorphous silicon solar cell has an active body with two or a series of layers of hydrogenated amorphous silicon arranged in a tandem stacked configuration with one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon arranged in tandem configuration can have the same bandgap or differing bandgaps.

  12. Permeability of CoNbZr amorphous thin films over a wide frequency range

    SciTech Connect (OSTI)

    Koyama, H.; Tsujimoto, H.; Shirae, K.

    1987-09-01

    CoNbZr amorphous films have attracted the attention of many researchers because of their high saturation magnetization, high permeability, low coercivity, and nearly zero magnetostriction. For these films to be used, one of the important magnetic properties is the behavior of the permeability over a wide frequency range. We have measured the permeability of a square-shaped magnetic film (13 mm x 55 mm) sputtered on a glass substrate from 1 MHz to 400 MHz using a stripline. Over 400 MHz, the permeability of the magnetic film was measured using a ring-shaped sample mounted in a coaxial fixture. The wall motion permeability of CoNbZr amorphous films decreases from 1 kHz to nearly zero at 1 MHz. The rotation permeability is constant to 100 MHz and ferromagnetic resonance is observed near 1 GHz.

  13. Low work function, stable thin films

    DOE Patents [OSTI]

    Dinh, Long N.; McLean, II, William; Balooch, Mehdi; Fehring, Jr., Edward J.; Schildbach, Marcus A.

    2000-01-01

    Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

  14. Growth direction of oblique angle electron beam deposited silicon monoxide thin films identified by optical second-harmonic generation

    SciTech Connect (OSTI)

    Vejling Andersen, Søren; Lund Trolle, Mads; Pedersen, Kjeld

    2013-12-02

    Oblique angle deposited (OAD) silicon monoxide (SiO) thin films forming tilted columnar structures have been characterized by second-harmonic generation. It was found that OAD SiO leads to a rotationally anisotropic second-harmonic response, depending on the optical angle of incidence. A model for the observed dependence of the second-harmonic signal on optical angle of incidence allows extraction of the growth direction of OAD films. The optically determined growth directions show convincing agreement with cross-sectional scanning electron microscopy images. In addition to a powerful characterization tool, these results demonstrate the possibilities for designing nonlinear optical devices through SiO OAD.

  15. Dual mechanical behaviour of hydrogen in stressed silicon nitride thin films

    SciTech Connect (OSTI)

    Volpi, F. Braccini, M.; Pasturel, A.; Devos, A.; Raymond, G.; Morin, P.

    2014-07-28

    In the present article, we report a study on the mechanical behaviour displayed by hydrogen atoms and pores in silicon nitride (SiN) films. A simple three-phase model is proposed to relate the physical properties (stiffness, film stress, mass density, etc.) of hydrogenated nanoporous SiN thin films to the volume fractions of hydrogen and pores. This model is then applied to experimental data extracted from films deposited by plasma enhanced chemical vapour deposition, where hydrogen content, stress, and mass densities range widely from 11% to 30%, ?2.8 to 1.5?GPa, and 2.0 to 2.8?g/cm{sup 3}, respectively. Starting from the conventional plotting of film's Young's modulus against film porosity, we first propose to correct the conventional calculation of porosity volume fraction with the hydrogen content, thus taking into account both hydrogen mass and concentration. The weight of this hydrogen-correction is found to evolve linearly with hydrogen concentration in tensile films (in accordance with a simple mass correction of the film density calculation), but a clear discontinuity is observed toward compressive stresses. Then, the effective volume occupied by hydrogen atoms is calculated taking account of the bond type (N-H or Si-H bonds), thus allowing a precise extraction of the hydrogen volume fraction. These calculations applied to tensile films show that both volume fractions of hydrogen and porosity are similar in magnitude and randomly distributed against Young's modulus. However, the expected linear dependence of the Young's modulus is clearly observed when both volume fractions are added. Finally, we show that the stiffer behaviour of compressive films cannot be only explained on the basis of this (hydrogen?+?porosity) volume fraction. Indeed this stiffness difference relies on a dual mechanical behaviour displayed by hydrogen atoms against the film stress state: while they participate to the stiffness in compressive films, hydrogen atoms mainly behave like

  16. Amorphous alumina thin films deposited on titanium: Interfacial chemistry and thermal oxidation barrier properties

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Baggetto, Loic; Charvillat, Cedric; Thebault, Yannick; Esvan, Jerome; Lafont, Marie-Christine; Scheid, Emmanuel; Veith, Gabriel M.; Vahlas, Constantin

    2015-12-02

    Ti/Al2O3 bilayer stacks are used as model systems to investigate the role of atomic layer deposition (ALD) and chemical vapor deposition (CVD) to prepare 30-180 nm thick amorphous alumina films as protective barriers for the medium temperature oxidation (500-600⁰C) of titanium, which is employed in aeronautic applications. X-ray diffraction (XRD), transmission electron microscopy (TEM) with selected area electron diffraction (SAED), and X-ray photoelectron spectroscopy (XPS) results show that the films produced from the direct liquid injection (DLI) CVD of aluminum tri-isopropoxide (ATI) are poor oxygen barriers. The films processed using the ALD of trimethylaluminum (TMA) show good barrier properties butmore » an extensive intermixing with Ti which subsequently oxidizes. In contrast, the films prepared from dimethyl aluminum isopropoxide (DMAI) by CVD are excellent oxygen barriers and show little intermixing with Ti. Overall, these measurements correlate the effect of the alumina coating thickness, morphology, and stoichiometry resulting from the preparation method to the oxidation barrier properties, and show that compact and stoichiometric amorphous alumina films offer superior barrier properties.« less

  17. Amorphous alumina thin films deposited on titanium: Interfacial chemistry and thermal oxidation barrier properties

    SciTech Connect (OSTI)

    Baggetto, Loic; Charvillat, Cedric; Thebault, Yannick; Esvan, Jerome; Lafont, Marie-Christine; Scheid, Emmanuel; Veith, Gabriel M.; Vahlas, Constantin

    2015-12-02

    Ti/Al2O3 bilayer stacks are used as model systems to investigate the role of atomic layer deposition (ALD) and chemical vapor deposition (CVD) to prepare 30-180 nm thick amorphous alumina films as protective barriers for the medium temperature oxidation (500-600⁰C) of titanium, which is employed in aeronautic applications. X-ray diffraction (XRD), transmission electron microscopy (TEM) with selected area electron diffraction (SAED), and X-ray photoelectron spectroscopy (XPS) results show that the films produced from the direct liquid injection (DLI) CVD of aluminum tri-isopropoxide (ATI) are poor oxygen barriers. The films processed using the ALD of trimethylaluminum (TMA) show good barrier properties but an extensive intermixing with Ti which subsequently oxidizes. In contrast, the films prepared from dimethyl aluminum isopropoxide (DMAI) by CVD are excellent oxygen barriers and show little intermixing with Ti. Overall, these measurements correlate the effect of the alumina coating thickness, morphology, and stoichiometry resulting from the preparation method to the oxidation barrier properties, and show that compact and stoichiometric amorphous alumina films offer superior barrier properties.

  18. Development of Commercial Technology for Thin Film Silicon Solar Cells on Glass: Cooperative Research and Development Final Report, CRADA Number CRD-07-209

    SciTech Connect (OSTI)

    Sopori, B.

    2013-03-01

    NREL has conducted basic research relating to high efficiency, low cost, thin film silicon solar cell design and the method of making solar cells. Two patents have been issued to NREL in the above field. In addition, specific process and metrology tools have been developed by NREL. Applied Optical Sciences Corp. (AOS) has expertise in the manufacture of solar cells and has developed its own unique concentrator technology. AOS wants to complement its solar cell expertise and its concentrator technology by manufacturing flat panel thin film silicon solar cell panels. AOS wants to take NREL's research to the next level, using it to develop commercially viable flat pane, thin film silicon solar cell panels. Such a development in equipment, process, and metrology will likely produce the lowest cost solar cell technology for both commercial and residential use. NREL's fundamental research capability and AOS's technology and industrial background are complementary to achieve this product development.

  19. Multi-jump magnetic switching in ion-beam sputtered amorphous Co{sub 20}Fe{sub 60}B{sub 20} thin films

    SciTech Connect (OSTI)

    Raju, M.; Chaudhary, Sujeet; Pandya, D. K.

    2013-08-07

    Unconventional multi-jump magnetization reversal and significant in-plane uniaxial magnetic anisotropy (UMA) in the ion-beam sputtered amorphous Co{sub 20}Fe{sub 60}B{sub 20}(5–75 nm) thin films grown on Si/amorphous SiO{sub 2} are reported. While such multi-jump behavior is observed in CoFeB(10 nm) film when the magnetic field is applied at 10°–20° away from the easy-axis, the same is observed in CoFeB(12.5 nm) film when the magnetic field is 45°–55° away from easy-axis. Unlike the previous reports of multi-jump switching in epitaxial films, their observance in the present case of amorphous CoFeB is remarkable. This multi-jump switching is found to disappear when the films are crystallized by annealing at 420 °C. The deposition geometry and the energy of the sputtered species appear to intrinsically induce a kind of bond orientation anisotropy in the films, which leads to the UMA in the as-grown amorphous CoFeB films. Exploitation of such multi-jump switching in amorphous CoFeB thin films could be of technological significance because of their applications in spintronic devices.

  20. Narrow band gap amorphous silicon semiconductors

    DOE Patents [OSTI]

    Madan, A.; Mahan, A.H.

    1985-01-10

    Disclosed is a narrow band gap amorphous silicon semiconductor comprising an alloy of amorphous silicon and a band gap narrowing element selected from the group consisting of Sn, Ge, and Pb, with an electron donor dopant selected from the group consisting of P, As, Sb, Bi and N. The process for producing the narrow band gap amorphous silicon semiconductor comprises the steps of forming an alloy comprising amorphous silicon and at least one of the aforesaid band gap narrowing elements in amount sufficient to narrow the band gap of the silicon semiconductor alloy below that of amorphous silicon, and also utilizing sufficient amounts of the aforesaid electron donor dopant to maintain the amorphous silicon alloy as an n-type semiconductor.

  1. Improvement of thermal stability of amorphous CoFeSiB thin films

    SciTech Connect (OSTI)

    Jimbo, M. Shimizu, T.; Fujiwara, Y.

    2015-05-07

    The excellent soft magnetic properties of amorphous (a-) CoFeSiB films make it suited for use in the yoke of granular-in-gap sensors, but only if their thermal stability can be improved. To this end, this study investigated the effects of adding small amounts of other metals on the magnetic and structural properties of a-CoFeSiB films. It was found that adding metals with relatively large atomic radii is an effective way to increase thermal stability, with both Ta and Hf showing good thermal stability after annealing at temperatures of 473 to 573?K. Indeed, a -(CoFeSiB){sub 96.2}Hf{sub 3.8} film was found to maintain its initial coercivity of 0.2?Oe without very little decrease in magnetization after annealing at 623?K. Furthermore, even after annealing at 673?K a -(CoFeSiB){sub 93.0}Hf{sub 7.0} film still had a relatively low coercivity of approximately 0.5?Oe.

  2. Amorphous silicon solar cell allowing infrared transmission

    DOE Patents [OSTI]

    Carlson, David E.

    1979-01-01

    An amorphous silicon solar cell with a layer of high index of refraction material or a series of layers having high and low indices of refraction material deposited upon a transparent substrate to reflect light of energies greater than the bandgap energy of the amorphous silicon back into the solar cell and transmit solar radiation having an energy less than the bandgap energy of the amorphous silicon.

  3. Superconducting nanowire single photon detectors fabricated from an amorphous Mo{sub 0.75}Ge{sub 0.25} thin film

    SciTech Connect (OSTI)

    Verma, V. B.; Lita, A. E.; Vissers, M. R.; Marsili, F.; Pappas, D. P.; Mirin, R. P.; Nam, S. W.

    2014-07-14

    We present the characteristics of superconducting nanowire single photon detectors (SNSPDs) fabricated from amorphous Mo{sub 0.75}Ge{sub 0.25} thin-films. Fabricated devices show a saturation of the internal detection efficiency at temperatures below 1?K, with system dark count rates below 500 cps. Operation in a closed-cycle cryocooler at 2.5?K is possible with system detection efficiencies exceeding 20% for SNSPDs which have not been optimized for high detection efficiency. Jitter is observed to vary between 69 ps at 250 mK and 187 ps at 2.5?K using room temperature amplifiers.

  4. Compensated amorphous-silicon solar cell

    DOE Patents [OSTI]

    Devaud, G.

    1982-06-21

    An amorphous silicon solar cell including an electrically conductive substrate, a layer of glow discharge deposited hydrogenated amorphous silicon having regions of differing conductivity with at least one region of intrinsic hydrogenated amorphous silicon. The layer of hydrogenated amorphous silicon has opposed first and second major surfaces where the first major surface contacts the elecrically conductive substrate and an electrode for electrically contacting the second major surface. The intrinsic hydrogenated amorphous silicon region is deposited in a glow discharge with an atmosphere which includes not less than about 0.02 atom percent mono-atomic boron. An improved N.I.P. solar cell is disclosed using a BF/sub 3/ doped intrinsic layer.

  5. Method of producing hydrogenated amorphous silicon film

    DOE Patents [OSTI]

    Wiesmann, Harold J.

    1980-01-01

    This invention relates to hydrogenated amorphous silicon produced by thermally decomposing silane (SiH.sub.4) or other gases comprising H and Si, from a tungsten or carbon foil heated to a temperature of about 1400.degree.-1600.degree. C., in a vacuum of about 10.sup.-6 to 19.sup.-4 torr, to form a gaseous mixture of atomic hydrogen and atomic silicon, and depositing said gaseos mixture onto a substrate independent of and outside said source of thermal decomposition, to form hydrogenated amorphous silicon. The presence of an ammonia atmosphere in the vacuum chamber enhances the photoconductivity of the hydrogenated amorphous silicon film.

  6. Towards high efficiency thin-film crystalline silicon solar cells: The roles of light trapping and non-radiative recombinations

    SciTech Connect (OSTI)

    Bozzola, A. Kowalczewski, P.; Andreani, L. C.

    2014-03-07

    Thin-film solar cells based on silicon have emerged as an alternative to standard thick wafers technology, but they are less efficient, because of incomplete absorption of sunlight, and non-radiative recombinations. In this paper, we focus on the case of crystalline silicon (c-Si) devices, and we present a full analytic electro-optical model for p-n junction solar cells with Lambertian light trapping. This model is validated against numerical solutions of the drift-diffusion equations. We use this model to investigate the interplay between light trapping, and bulk and surface recombination. Special attention is paid to surface recombination processes, which become more important in thinner devices. These effects are further amplified due to the textures required for light trapping, which lead to increased surface area. We show that c-Si solar cells with thickness of a few microns can overcome 20% efficiency and outperform bulk ones when light trapping is implemented. The optimal device thickness in presence of light trapping, bulk and surface recombination, is quantified to be in the range of 1080??m, depending on the bulk quality. These results hold, provided the effective surface recombination is kept below a critical level of the order of 100?cm/s. We discuss the possibility of meeting this requirement, in the context of state-of-the-art techniques for light trapping and surface passivation. We show that our predictions are within the capability of present day silicon technologies.

  7. Mechanism of tailored magnetic anisotropy in amorphous Co{sub 68}Fe{sub 24}Zr{sub 8} thin films

    SciTech Connect (OSTI)

    Fu, Yu E-mail: cangcangzhulin@gmail.com; Meckenstock, R.; Farle, M.; Barsukov, I.; Lindner, J.; Raanaei, H.; Hjörvarsson, B.

    2014-02-17

    The mechanism of tailored magnetic anisotropy in amorphous Co{sub 68}Fe{sub 24}Zr{sub 8} thin films was investigated by ferromagnetic resonance (FMR) on samples deposited without an applied magnetic field, with an out-of-plane field and an in-plane field. Analysis of FMR spectra profiles, high frequency susceptibility calculations, and statistical simulations using a distribution of local uniaxial magnetic anisotropy reveal the presence of atomic configurations with local uniaxial anisotropy, of which the direction can be tailored while the magnitude remains at an intrinsically constant value of 3.0(2) kJ/m{sup 3}. The in-plane growth field remarkably sharpens the anisotropy distribution and increases the sample homogeneity. The results benefit designing multilayer spintronic devices based on highly homogeneous amorphous layers with tailored magnetic anisotropy.

  8. Electrical properties and surface morphology of electron beam evaporated p-type silicon thin films on polyethylene terephthalate for solar cells applications

    SciTech Connect (OSTI)

    Ang, P. C.; Ibrahim, K.; Pakhuruddin, M. Z.

    2015-04-24

    One way to realize low-cost thin film silicon (Si) solar cells fabrication is by depositing the films with high-deposition rate and manufacturing-compatible electron beam (e-beam) evaporation onto inexpensive foreign substrates such as glass or plastic. Most of the ongoing research is reported on e-beam evaporation of Si films on glass substrates to make polycrystalline solar cells but works combining both e-beam evaporation and plastic substrates are still scarce in the literature. This paper studies electrical properties and surface morphology of 1 µm electron beam evaporated Al-doped p-type silicon thin films on textured polyethylene terephthalate (PET) substrate for application as an absorber layer in solar cells. In this work, Si thin films with different doping concentrations (including an undoped reference) are prepared by e-beam evaporation. Energy dispersion X-ray (EDX) showed that the Si films are uniformly doped by Al dopant atoms. With increased Al/Si ratio, doping concentration increased while both resistivity and carrier mobility of the films showed opposite relationships. Root mean square (RMS) surface roughness increased. Overall, the Al-doped Si film with Al/Si ratio of 2% (doping concentration = 1.57×10{sup 16} atoms/cm{sup 3}) has been found to provide the optimum properties of a p-type absorber layer for fabrication of thin film Si solar cells on PET substrate.

  9. Amorphous InGaZnO thin-film transistor active pixel sensor x-ray imager for digital breast tomosynthesis

    SciTech Connect (OSTI)

    Zhao, Chumin; Kanicki, Jerzy

    2014-09-15

    Purpose: The breast cancer detection rate for digital breast tomosynthesis (DBT) is limited by the x-ray image quality. The limiting Nyquist frequency for current DBT systems is around 5?lp/mm, while the fine image details contained in the high spatial frequency region (>5?lp/mm) are lost. Also today the tomosynthesis patient dose is high (0.673.52?mGy). To address current issues, in this paper, for the first time, a high-resolution low-dose organic photodetector/amorphous InGaZnO thin-film transistor (a-IGZO TFT) active pixel sensor (APS) x-ray imager is proposed for next generation DBT systems. Methods: The indirect x-ray detector is based on a combination of a novel low-cost organic photodiode (OPD) and a cesium iodide-based (CsI:Tl) scintillator. The proposed APS x-ray imager overcomes the difficulty of weak signal detection, when small pixel size and low exposure conditions are used, by an on-pixel signal amplification with a significant charge gain. The electrical performance of a-IGZO TFT APS pixel circuit is investigated by SPICE simulation using modified Rensselaer Polytechnic Institute amorphous silicon (a-Si:H) TFT model. Finally, the noise, detective quantum efficiency (DQE), and resolvability of the complete system are modeled using the cascaded system formalism. Results: The result demonstrates that a large charge gain of 31122 is achieved for the proposed high-mobility (520 cm{sup 2}/V?s) amorphous metal-oxide TFT APS. The charge gain is sufficient to eliminate the TFT thermal noise, flicker noise as well as the external readout circuit noise. Moreover, the low TFT (<10{sup ?13} A) and OPD (<10{sup ?8} A/cm{sup 2}) leakage currents can further reduce the APS noise. Cascaded system analysis shows that the proposed APS imager with a 75??m pixel pitch can effectively resolve the Nyquist frequency of 6.67 lp/mm, which can be further improved to ?10?lp/mm if the pixel pitch is reduced to 50??m. Moreover, the detector entrance exposure per projection

  10. Phonon renormalization and Raman spectral evolution through amorphous to crystalline transitions in Sb{sub 2}Te{sub 3} thin films

    SciTech Connect (OSTI)

    Secor, Jeff; Zhao, Lukas; Krusin-Elbaum, Lia; Harris, Matt A.; Deng, Haiming; Raoux, Simone

    2014-06-02

    A symmetry specific phonon mode renormalization is observed across an amorphous to crystalline phase transformation in thin films of the topological material Sb{sub 2}Te{sub 3} using Raman spectroscopy. We present evidence for local crystalline symmetry in the amorphous state, eventhough, the q = 0 Raman selection rule is broken due to strong structural disorder. At crystallization, the in-plane polarized (E{sub g}{sup 2}) mode abruptly sharpens while the out-of-plane polarized (A{sub 1g}) modes are only weakly effected. This effect unique to the E{sub g} symmetry is exceptional considering that polarized spectra and comparison of the single phonon density of states between the amorphous and crystalline phases suggest that short range order of the amorphous phase is, on the average, similar to that of the crystalline material while electrical transport measurements reveal a sharp insulator-to-metal transition. Our findings point to the important role of anisotropic disorder affecting potential applications of topological and phase-change based electronics.

  11. Radiation resistance of thin-film solar cells for space photovoltaic power

    SciTech Connect (OSTI)

    Woodyard, J.R.; Landis, G.A.

    1991-01-01

    Copper indium diselenide, cadmium telluride, and amorphous silicon alloy solar cells have achieved noteworthy performance and are currently being studied for space power applications. Cadmium sulfide cells had been the subject of much effort but are no longer considered for space applications. A review is presented of what is known about the radiation degradation of thin film solar cells in space. Experimental cadmium telluride and amorphous silicon alloy cells are reviewed. Damage mechanisms and radiation induced defect generation and passivation in the amorphous silicon alloy cell are discussed in detail due to the greater amount of experimental data available.

  12. Photovoltaic Polycrystalline Thin-Film Cell Basics | Department...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Thin films are unlike single-crystal silicon cells, which must be individually interconnected into a module. Thin-film devices can be made as a single unit-that is, ...

  13. Effects of low-temperature (120 °C) annealing on the carrier concentration and trap density in amorphous indium gallium zinc oxide thin film transistors

    SciTech Connect (OSTI)

    Kim, Jae-sung; Piao, Mingxing; Jang, Ho-Kyun; Kim, Gyu-Tae; Oh, Byung Su; Joo, Min-Kyu; Ahn, Seung-Eon

    2014-12-28

    We report an investigation of the effects of low-temperature annealing on the electrical properties of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs). X-ray photoelectron spectroscopy was used to characterize the charge carrier concentration, which is related to the density of oxygen vacancies. The field-effect mobility was found to decrease as a function of the charge carrier concentration, owing to the presence of band-tail states. By employing the transmission line method, we show that the contact resistance did not significantly contribute to the changes in device performance after annealing. In addition, using low-frequency noise analyses, we found that the trap density decreased by a factor of 10 following annealing at 120 °C. The switching operation and on/off ratio of the a-IGZO TFTs improved considerably after low-temperature annealing.

  14. Crystallization and doping of amorphous silicon on low temperature plastic

    DOE Patents [OSTI]

    Kaschmitter, J.L.; Truher, J.B.; Weiner, K.H.; Sigmon, T.W.

    1994-09-13

    A method or process of crystallizing and doping amorphous silicon (a-Si) on a low-temperature plastic substrate using a short pulsed high energy source in a selected environment, without heat propagation and build-up in the substrate is disclosed. The pulsed energy processing of the a-Si in a selected environment, such as BF3 and PF5, will form a doped micro-crystalline or poly-crystalline silicon (pc-Si) region or junction point with improved mobilities, lifetimes and drift and diffusion lengths and with reduced resistivity. The advantage of this method or process is that it provides for high energy materials processing on low cost, low temperature, transparent plastic substrates. Using pulsed laser processing a high (>900 C), localized processing temperature can be achieved in thin films, with little accompanying temperature rise in the substrate, since substrate temperatures do not exceed 180 C for more than a few microseconds. This method enables use of plastics incapable of withstanding sustained processing temperatures (higher than 180 C) but which are much lower cost, have high tolerance to ultraviolet light, have high strength and good transparency, compared to higher temperature plastics such as polyimide. 5 figs.

  15. Crystallization and doping of amorphous silicon on low temperature plastic

    DOE Patents [OSTI]

    Kaschmitter, James L.; Truher, Joel B.; Weiner, Kurt H.; Sigmon, Thomas W.

    1994-01-01

    A method or process of crystallizing and doping amorphous silicon (a-Si) on a low-temperature plastic substrate using a short pulsed high energy source in a selected environment, without heat propagation and build-up in the substrate. The pulsed energy processing of the a-Si in a selected environment, such as BF3 and PF5, will form a doped micro-crystalline or poly-crystalline silicon (pc-Si) region or junction point with improved mobilities, lifetimes and drift and diffusion lengths and with reduced resistivity. The advantage of this method or process is that it provides for high energy materials processing on low cost, low temperature, transparent plastic substrates. Using pulsed laser processing a high (>900.degree. C.), localized processing temperature can be achieved in thin films, with little accompanying temperature rise in the substrate, since substrate temperatures do not exceed 180.degree. C. for more than a few microseconds. This method enables use of plastics incapable of withstanding sustained processing temperatures (higher than 180.degree. C.) but which are much lower cost, have high tolerance to ultraviolet light, have high strength and good transparency, compared to higher temperature plastics such as polyimide.

  16. Medium-range order in hydrogenated amorphous silicon measured by fluctuation microscopy

    SciTech Connect (OSTI)

    Voyles, P. M.; Treacy, M. M. J.; Jin, H.-C.; Abelson, J. R.; Gibson, J. M.; Guha, S.; Crandall, R. S.

    2000-04-17

    The authors have characterized with fluctuation electron microscopy the medium-range order of hydrogenated amorphous silicon thin films deposited by a variety of methods. Films were deposited by reactive magnetron sputtering, hot-wire chemical vapor deposition, and plasma enhanced chemical vapor deposition with and without H{sub 2} dilution of the SiH{sub 4} precursor gas. All of the films show the signature of the paracrystalline structure typical of amorphous Si. There are small variations in the degree of medium-range order with deposition methods and H{sub 2} content. The PECVD film grown with high H{sub 2} dilution contains Si crystals {approximately} 5 nm in diameter at a density of {approximately} 10{sup 9} cm{sup 2}. The amorphous matrix surrounding these crystals shows no difference in medium-range order from the standard PECVD film.

  17. Method for formation of thin film transistors on plastic substrates

    DOE Patents [OSTI]

    Carey, P.G.; Smith, P.M.; Sigmon, T.W.; Aceves, R.C.

    1998-10-06

    A process for formation of thin film transistors (TFTs) on plastic substrates replaces standard thin film transistor fabrication techniques, and uses sufficiently lower processing temperatures so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The process relies on techniques for depositing semiconductors, dielectrics, and metals at low temperatures; crystallizing and doping semiconductor layers in the TFT with a pulsed energy source; and creating top-gate self-aligned as well as back-gate TFT structures. The process enables the fabrication of amorphous and polycrystalline channel silicon TFTs at temperatures sufficiently low to prevent damage to plastic substrates. The process has use in large area low cost electronics, such as flat panel displays and portable electronics. 5 figs.

  18. Method for formation of thin film transistors on plastic substrates

    DOE Patents [OSTI]

    Carey, Paul G.; Smith, Patrick M.; Sigmon, Thomas W.; Aceves, Randy C.

    1998-10-06

    A process for formation of thin film transistors (TFTs) on plastic substrates replaces standard thin film transistor fabrication techniques, and uses sufficiently lower processing temperatures so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The process relies on techniques for depositing semiconductors, dielectrics, and metals at low temperatures; crystallizing and doping semiconductor layers in the TFT with a pulsed energy source; and creating top-gate self-aligned as well as back-gate TFT structures. The process enables the fabrication of amorphous and polycrystalline channel silicon TFTs at temperatures sufficiently low to prevent damage to plastic substrates. The process has use in large area low cost electronics, such as flat panel displays and portable electronics.

  19. Growing antiphase-domain-free GaAs thin films out of highly ordered planar nanowire arrays on exact (001) silicon

    SciTech Connect (OSTI)

    Li, Qiang; Ng, Kar Wei; Lau, Kei May

    2015-02-16

    We report the use of highly ordered, dense, and regular arrays of in-plane GaAs nanowires as building blocks to produce antiphase-domain-free GaAs thin films on exact (001) silicon. High quality GaAs nanowires were grown on V-grooved Si (001) substrates using the selective aspect ratio trapping concept. The 4.1% lattice mismatch has been accommodated by the initial GaAs, a few nanometer-thick with high density stacking faults. The bulk of the GaAs wires exhibited smooth facets and a low defect density. An unusual defect trapping mechanism by a tiara-like structure formed by Si undercuts was discovered. As a result, we were able to grow large-area antiphase-domain-free GaAs thin films out of the nanowires without using SiO{sub 2} sidewalls for defect termination. Analysis from XRD ?-rocking curves yielded full-width-at-half-maximum values of 238 and 154?arc sec from 900 to 2000?nm GaAs thin films, respectively, indicating high crystalline quality. The growth scheme in this work offers a promising path towards integrated III-V electronic, photonic, or photovoltaic devices on large scale silicon platform.

  20. Thin, High Lifetime Silicon Wafers with No Sawing; Re-crystallization in a Thin Film Capsule

    SciTech Connect (OSTI)

    Emanuel Sachs Tonio Buonassisi

    2013-01-16

    The project fits within the area of renewable energy called photovoltaics (PV), or the generation of electricity directly from sunlight using semiconductor devices. PV has the greatest potential of any renewable energy technology. The vast majority of photovoltaic modules are made on crystalline silicon wafers and these wafers accounts for the largest fraction of the cost of a photovoltaic module. Thus, a method of making high quality, low cost wafers would be extremely beneficial to the PV industry The industry standard technology creates wafers by casting an ingot and then sawing wafers from the ingot. Sawing rendered half of the highly refined silicon feedstock as un-reclaimable dust. Being a brittle material, the sawing is actually a type of grinding operation which is costly both in terms of capital equipment and in terms of consumables costs. The consumables costs associated with the wire sawing technology are particularly burdensome and include the cost of the wire itself (continuously fed, one time use), the abrasive particles, and, waste disposal. The goal of this project was to make wafers directly from molten silicon with no sawing required. The fundamental concept was to create a very low cost (but low quality) wafer of the desired shape and size and then to improve the quality of the wafer by a specialized thermal treatment (called re-crystallization). Others have attempted to create silicon sheet by recrystallization with varying degrees of success. Key among the difficulties encountered by others were: a) difficulty in maintaining the physical shape of the sheet during the recrystallization process and b) difficulty in maintaining the cleanliness of the sheet during recrystallization. Our method solved both of these challenges by encapsulating the preform wafer in a protective capsule prior to recrystallization (see below). The recrystallization method developed in this work was extremely effective at maintaining the shape and the cleanliness of the

  1. Structural characterisation of BaTiO{sub 3} thin films deposited on SrRuO{sub 3}/YSZ buffered silicon substrates and silicon microcantilevers

    SciTech Connect (OSTI)

    Colder, H.; Jorel, C. Mchin, L.; Domengs, B.; Marie, P.; Boisserie, M.; Guillon, S.; Nicu, L.; Galdi, A.

    2014-02-07

    We report on the progress towards an all epitaxial oxide layer technology on silicon substrates for epitaxial piezoelectric microelectromechanical systems. (101)-oriented epitaxial tetragonal BaTiO{sub 3} (BTO) thin films were deposited at two different oxygen pressures, 5.10{sup ?2} mbar and 5.10{sup ?3} mbar, on SrRuO{sub 3}/Yttria-stabilized zirconia (YSZ) buffered silicon substrates by pulsed laser deposition. The YSZ layer full (001) orientation allowed the further growth of a fully (110)-oriented conductive SrRuO{sub 3} electrode as shown by X-ray diffraction. The tetragonal structure of the BTO films, which is a prerequisite for the piezoelectric effect, was identified by Raman spectroscopy. In the BTO film deposited at 5.10{sup ?2} mbar strain was mostly localized inside the BTO grains whereas at 5.10{sup ?3} mbar, it was localized at the grain boundaries. The BTO/SRO/YSZ layers were finally deposited on Si microcantilevers at an O{sub 2} pressure of 5.10{sup ?3} mbar. The strain level was low enough to evaluate the BTO Young modulus. Transmission electron microscopy (TEM) was used to investigate the epitaxial quality of the layers and their epitaxial relationship on plain silicon wafers as well as on released microcantilevers, thanks to Focused-Ion-Beam TEM lamella preparation.

  2. Thin Film Transistors On Plastic Substrates

    DOE Patents [OSTI]

    Carey, Paul G.; Smith, Patrick M.; Sigmon, Thomas W.; Aceves, Randy C.

    2004-01-20

    A process for formation of thin film transistors (TFTs) on plastic substrates replaces standard thin film transistor fabrication techniques, and uses sufficiently lower processing temperatures so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The silicon based thin film transistor produced by the process includes a low temperature substrate incapable of withstanding sustained processing temperatures greater than about 250.degree. C., an insulating layer on the substrate, a layer of silicon on the insulating layer having sections of doped silicon, undoped silicon, and poly-silicon, a gate dielectric layer on the layer of silicon, a layer of gate metal on the dielectric layer, a layer of oxide on sections of the layer of silicon and the layer of gate metal, and metal contacts on sections of the layer of silicon and layer of gate metal defining source, gate, and drain contacts, and interconnects.

  3. Neutron irradiation induced amorphization of silicon carbide

    SciTech Connect (OSTI)

    Snead, L.L.; Hay, J.C.

    1998-09-01

    This paper provides the first known observation of silicon carbide fully amorphized under neutron irradiation. Both high purity single crystal hcp and high purity, highly faulted (cubic) chemically vapor deposited (CVD) SiC were irradiated at approximately 60 C to a total fast neutron fluence of 2.6 {times} 10{sup 25} n/m{sup 2}. Amorphization was seen in both materials, as evidenced by TEM, electron diffraction, and x-ray diffraction techniques. Physical properties for the amorphized single crystal material are reported including large changes in density ({minus}10.8%), elastic modulus as measured using a nanoindentation technique ({minus}45%), hardness as measured by nanoindentation ({minus}45%), and standard Vickers hardness ({minus}24%). Similar property changes are observed for the critical temperature for amorphization at this neutron dose and flux, above which amorphization is not possible, is estimated to be greater than 130 C.

  4. Inverted amorphous silicon solar cell utilizing cermet layers

    DOE Patents [OSTI]

    Hanak, Joseph J.

    1979-01-01

    An amorphous silicon solar cell incorporating a transparent high work function metal cermet incident to solar radiation and a thick film cermet contacting the amorphous silicon opposite to said incident surface.

  5. An amorphous phase formation at palladium / silicon oxide (Pd...

    Office of Scientific and Technical Information (OSTI)

    An amorphous phase formation at palladium silicon oxide (PdSiOsub x) interface ... Title: An amorphous phase formation at palladium silicon oxide (PdSiOsub x) interface ...

  6. Metal electrode for amorphous silicon solar cells

    DOE Patents [OSTI]

    Williams, Richard

    1983-01-01

    An amorphous silicon solar cell having an N-type region wherein the contact to the N-type region is composed of a material having a work function of about 3.7 electron volts or less. Suitable materials include strontium, barium and magnesium and rare earth metals such as gadolinium and yttrium.

  7. Fabricating amorphous silicon solar cells by varying the temperature _of the substrate during deposition of the amorphous silicon layer

    DOE Patents [OSTI]

    Carlson, David E.

    1982-01-01

    An improved process for fabricating amorphous silicon solar cells in which the temperature of the substrate is varied during the deposition of the amorphous silicon layer is described. Solar cells manufactured in accordance with this process are shown to have increased efficiencies and fill factors when compared to solar cells manufactured with a constant substrate temperature during deposition of the amorphous silicon layer.

  8. Microstructure of amorphous-silicon-based solar cell materials by small-angle x-ray scattering. Annual subcontract report, 6 April 1994--5 April 1995

    SciTech Connect (OSTI)

    Williamson, D.L.

    1995-08-01

    The general objective of this research is to provide detailed microstructural information on the amorphous-silicon-based, thin-film materials under development for improved multijunction solar cells. The experimental technique used is small-angle x-ray scattering (SAXS) providing microstructural data on microvoid fractions, sizes, shapes, and their preferred orientations. Other microstructural features such as alloy segregation, hydrogen-rich clusters and alloy short-range order are probed.

  9. Electromechanical response of amorphous LaAlO{sub 3} thin film probed by scanning probe microscopies

    SciTech Connect (OSTI)

    Borowiak, Alexis S.; Baboux, Nicolas; Albertini, David; Gautier, Brice; Vilquin, Bertrand; Saint Girons, Guillaume; Pelloquin, Sylvain

    2014-07-07

    The electromechanical response of a 3 nm thick amorphous LaAlO{sub 3} layer obtained by molecular beam epitaxy has been studied using scanning probe microscopies. Although this kind of sample is not ferroelectric due to its amorphous nature, the resulting images are identical to what is generally obtained on truly ferroelectric samples probed by piezoresponse force microscopy: domains of apparently opposite polarisation are detected, and perfect, square shaped hysteresis loops are recorded. Moreover, written patterns are stable within 72 h. We discuss in the general case the possible origins of this behaviour in terms of charge injection, ionic conduction and motion of oxygen vacancies. In the case presented in this paper, since the writing process has been conducted with applied voltages lower than the injection threshold measured by conductive atomic force Microscopy, allowing to withdraw the hypothesis of charge injection in the sample, we propose that a bistable distribution of oxygen vacancies is responsible for this contrast.

  10. Crystalline to amorphous transformation in silicon

    SciTech Connect (OSTI)

    Cheruvu, S.M.

    1982-09-01

    In the present investigation, an attempt was made to understand the fundamental mechanism of crystalline-to-amorphous transformation in arsenic implanted silicon using high resolution electron microscopy. A comparison of the gradual disappearance of simulated lattice fringes with increasing Frenkel pair concentration with the experimental observation of sharp interfaces between crystalline and amorphous regions was carried out leading to the conclusion that when the defect concentration reaches a critical value, the crystal does relax to an amorphous state. Optical diffraction experiments using atomic models also supported this hypothesis. Both crystalline and amorphous zones were found to co-exist with sharp interfaces at the atomic level. Growth of the amorphous fraction depends on the temperature, dose rate and the mass of the implanted ion. Preliminary results of high energy electron irradiation experiments at 1.2 MeV also suggested that clustering of point defects occurs near room temperature. An observation in a high resolution image of a small amorphous zone centered at the core of a dislocation is presented as evidence that the nucleation of an amorphous phase is heterogeneous in nature involving clustering or segregation of point defects near existing defects.

  11. In situ spectroscopic study of the plastic deformation of amorphous silicon under nonhydrostatic conditions induced by indentation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gerbig, Yvonne B.; Michaels, C. A.; Bradby, Jodie E.; Haberl, Bianca; Cook, Robert F.

    2015-12-17

    Indentation-induced plastic deformation of amorphous silicon (a-Si) thin films was studied by in situ Raman imaging of the deformed contact region of an indented sample, employing a Raman spectroscopy-enhanced instrumented indentation technique (IIT). The occurrence and evolving spatial distribution of changes in the a-Si structure caused by processes, such as polyamorphization and crystallization, induced by indentation loading were observed. Furthermore, the obtained experimental results are linked with previously published work on the plastic deformation of a-Si under hydrostatic compression and shear deformation to establish a model for the deformation behavior of a-Si under indentation loading.

  12. High resolution amorphous silicon radiation detectors

    DOE Patents [OSTI]

    Street, Robert A.; Kaplan, Selig N.; Perez-Mendez, Victor

    1992-01-01

    A radiation detector employing amorphous Si:H cells in an array with each detector cell having at least three contiguous layers (n type, intrinsic, p type), positioned between two electrodes to which a bias voltage is applied. An energy conversion layer atop the silicon cells intercepts incident radiation and converts radiation energy to light energy of a wavelength to which the silicon cells are responsive. A read-out device, positioned proximate to each detector element in an array allows each such element to be interrogated independently to determine whether radiation has been detected in that cell. The energy conversion material may be a layer of luminescent material having a columnar structure. In one embodiment a column of luminescent material detects the passage therethrough of radiation to be detected and directs a light beam signal to an adjacent a-Si:H film so that detection may be confined to one or more such cells in the array. One or both electrodes may have a comb structure, and the teeth of each electrode comb may be interdigitated for capacitance reduction. The amorphous Si:H film may be replaced by an amorphous Si:Ge:H film in which up to 40 percent of the amorphous material is Ge. Two dimensional arrays may be used in X-ray imaging, CT scanning, crystallography, high energy physics beam tracking, nuclear medicine cameras and autoradiography.

  13. High resolution amorphous silicon radiation detectors

    DOE Patents [OSTI]

    Street, R.A.; Kaplan, S.N.; Perez-Mendez, V.

    1992-05-26

    A radiation detector employing amorphous Si:H cells in an array with each detector cell having at least three contiguous layers (n-type, intrinsic, p-type), positioned between two electrodes to which a bias voltage is applied. An energy conversion layer atop the silicon cells intercepts incident radiation and converts radiation energy to light energy of a wavelength to which the silicon cells are responsive. A read-out device, positioned proximate to each detector element in an array allows each such element to be interrogated independently to determine whether radiation has been detected in that cell. The energy conversion material may be a layer of luminescent material having a columnar structure. In one embodiment a column of luminescent material detects the passage therethrough of radiation to be detected and directs a light beam signal to an adjacent a-Si:H film so that detection may be confined to one or more such cells in the array. One or both electrodes may have a comb structure, and the teeth of each electrode comb may be interdigitated for capacitance reduction. The amorphous Si:H film may be replaced by an amorphous Si:Ge:H film in which up to 40 percent of the amorphous material is Ge. Two dimensional arrays may be used in X-ray imaging, CT scanning, crystallography, high energy physics beam tracking, nuclear medicine cameras and autoradiography. 18 figs.

  14. Effect of top gate bias on photocurrent and negative bias illumination stress instability in dual gate amorphous indium-gallium-zinc oxide thin-film transistor

    SciTech Connect (OSTI)

    Lee, Eunji; Chowdhury, Md Delwar Hossain; Park, Min Sang; Jang, Jin

    2015-12-07

    We have studied the effect of top gate bias (V{sub TG}) on the generation of photocurrent and the decay of photocurrent for back channel etched inverted staggered dual gate structure amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film-transistors. Upon 5 min of exposure of 365 nm wavelength and 0.7 mW/cm{sup 2} intensity light with negative bottom gate bias, the maximum photocurrent increases from 3.29 to 322 pA with increasing the V{sub TG} from −15 to +15 V. By changing V{sub TG} from negative to positive, the Fermi level (E{sub F}) shifts toward conduction band edge (E{sub C}), which substantially controls the conversion of neutral vacancy to charged one (V{sub O} → V{sub O}{sup +}/V{sub O}{sup 2+} + e{sup −}/2e{sup −}), peroxide (O{sub 2}{sup 2−}) formation or conversion of ionized interstitial (O{sub i}{sup 2−}) to neutral interstitial (O{sub i}), thus electron concentration at conduction band. With increasing the exposure time, more carriers are generated, and thus, maximum photocurrent increases until being saturated. After negative bias illumination stress, the transfer curve shows −2.7 V shift at V{sub TG} = −15 V, which gradually decreases to −0.42 V shift at V{sub TG} = +15 V. It clearly reveals that the position of electron quasi-Fermi level controls the formation of donor defects (V{sub O}{sup +}/V{sub O}{sup 2+}/O{sub 2}{sup 2−}/O{sub i}) and/or hole trapping in the a-IGZO /interfaces.

  15. Thin-film Rechargeable Lithium Batteries

    DOE R&D Accomplishments [OSTI]

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

    1995-06-01

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

  16. Porous thin films

    DOE Patents [OSTI]

    Xu, Ting

    2015-11-17

    Compositions of porous thin films and methods of making are provided. The methods involve self-assembly of a cyclic peptide in the presence of a block copolymer.

  17. Three dimensional amorphous silicon/microcrystalline silicon solar cells

    DOE Patents [OSTI]

    Kaschmitter, J.L.

    1996-07-23

    Three dimensional deep contact amorphous silicon/microcrystalline silicon (a-Si/{micro}c-Si) solar cells are disclosed which use deep (high aspect ratio) p and n contacts to create high electric fields within the carrier collection volume material of the cell. The deep contacts are fabricated using repetitive pulsed laser doping so as to create the high aspect p and n contacts. By the provision of the deep contacts which penetrate the electric field deep into the material where the high strength of the field can collect many of the carriers, thereby resulting in a high efficiency solar cell. 4 figs.

  18. Three dimensional amorphous silicon/microcrystalline silicon solar cells

    DOE Patents [OSTI]

    Kaschmitter, James L.

    1996-01-01

    Three dimensional deep contact amorphous silicon/microcrystalline silicon (a-Si/.mu.c-Si) solar cells which use deep (high aspect ratio) p and n contacts to create high electric fields within the carrier collection volume material of the cell. The deep contacts are fabricated using repetitive pulsed laser doping so as to create the high aspect p and n contacts. By the provision of the deep contacts which penetrate the electric field deep into the material where the high strength of the field can collect many of the carriers, thereby resulting in a high efficiency solar cell.

  19. NMR Studies of Molecular Hydrogen in Hydrogenated Amorphous Silicon

    SciTech Connect (OSTI)

    Su, T.; Chen, S.; Taylor, P. C.; Crandall, R. S.; Mahan, A. H.

    2000-01-01

    Using NMR, the concentrations of molecular hydrogen have been measured directly in hydrogenated amorphous silicon made by the hot wire chemical vapor deposition (HWCVD) technique.

  20. Subtleties of capacitance transients in amorphous silicon

    SciTech Connect (OSTI)

    Crandall, R.S.; Lips, K.

    1996-12-31

    Using junction capacitance methods, the authors describe the effect of contacts on charge emission transients in n-type hydrogenated amorphous silicon. The results demonstrate some of the difficulties encountered in observing and interpreting anomalous temperature independent emission transients (slow relaxation). In this paper, the authors present additional data and reconcile the absence of anomalous emission transients in some cases with a discussion of the dynamics of depletion width filling. The authors show that the transient capacitance response of Schottky structure is not only related to the contact configuration but is connected to the rate of charge injection into the depletion region.

  1. Air stable n-doping of WSe{sub 2} by silicon nitride thin films with tunable fixed charge density

    SciTech Connect (OSTI)

    Chen, Kevin; Kiriya, Daisuke; Hettick, Mark; Tosun, Mahmut; Ha, Tae-Jun; Madhvapathy, Surabhi Rao; Desai, Sujay; Sachid, Angada; Javey, Ali

    2014-09-01

    Stable n-doping of WSe{sub 2} using thin films of SiN{sub x} deposited on the surface via plasma-enhanced chemical vapor deposition is presented. Positive fixed charge centers inside SiN{sub x} act to dope WSe{sub 2} thin flakes n-type via field-induced effect. The electron concentration in WSe{sub 2} can be well controlled up to the degenerate limit by simply adjusting the stoichiometry of the SiN{sub x} through deposition process parameters. For the high doping limit, the Schottky barrier width at the metal/WSe{sub 2} junction is significantly thinned, allowing for efficient electron injection via tunneling. Using this doping scheme, we demonstrate air-stable WSe{sub 2} n-MOSFETs with a mobility of ?70 cm{sup 2}/V?s.

  2. Superlattice doped layers for amorphous silicon photovoltaic cells

    DOE Patents [OSTI]

    Arya, Rajeewa R.

    1988-01-12

    Superlattice doped layers for amorphous silicon photovoltaic cells comprise a plurality of first and second lattices of amorphous silicon alternatingly formed on one another. Each of the first lattices has a first optical bandgap and each of the second lattices has a second optical bandgap different from the first optical bandgap. A method of fabricating the superlattice doped layers also is disclosed.

  3. Method for improving the stability of amorphous silicon

    DOE Patents [OSTI]

    Branz, Howard M.

    2004-03-30

    A method of producing a metastable degradation resistant amorphous hydrogenated silicon film is provided, which comprises the steps of growing a hydrogenated amorphous silicon film, the film having an exposed surface, illuminating the surface using an essentially blue or ultraviolet light to form high densities of a light induced defect near the surface, and etching the surface to remove the defect.

  4. Thin film hydrogen sensor

    DOE Patents [OSTI]

    Cheng, Y.T.; Poli, A.A.; Meltser, M.A.

    1999-03-23

    A thin film hydrogen sensor includes a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end. 5 figs.

  5. Thin film hydrogen sensor

    DOE Patents [OSTI]

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

    1999-01-01

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

  6. Generation of low work function, stable compound thin films by laser ablation

    DOE Patents [OSTI]

    Dinh, Long N.; McLean, II, William; Balooch, Mehdi; Fehring, Jr., Edward J.; Schildbach, Marcus A.

    2001-01-01

    Generation of low work function, stable compound thin films by laser ablation. Compound thin films with low work function can be synthesized by simultaneously laser ablating silicon, for example, and thermal evaporating an alkali metal into an oxygen environment. For example, the compound thin film may be composed of Si/Cs/O. The work functions of the thin films can be varied by changing the silicon/alkali metal/oxygen ratio. Low work functions of the compound thin films deposited on silicon substrates were confirmed by ultraviolet photoelectron spectroscopy (UPS). The compound thin films are stable up to 500.degree. C. as measured by x-ray photoelectron spectroscopy (XPS). Tests have established that for certain chemical compositions and annealing temperatures of the compound thin films, negative electron affinity (NEA) was detected. The low work function, stable compound thin films can be utilized in solar cells, field emission flat panel displays, electron guns, and cold cathode electron guns.

  7. Structural characterization of impurified zinc oxide thin films

    SciTech Connect (OSTI)

    Trinca, L. M.; Galca, A. C. Stancu, V. Chirila, C. Pintilie, L.

    2014-11-05

    Europium doped zinc oxide (Eu:ZnO) thin films have been obtained by pulsed laser deposition (PLD). 002 textured thin films were achieved on glass and silicon substrates, while hetero-epilayers and homo-epilayers have been attained on single crystal SrTiO{sub 3} and ZnO, respectively. X-ray Diffraction (XRD) was employed to characterize the Eu:ZnO thin films. Extended XRD studies confirmed the different thin film structural properties as function of chosen substrates.

  8. Amorphous silicon carbide passivating layers for crystalline-silicon-based heterojunction solar cells

    SciTech Connect (OSTI)

    Boccard, Mathieu; Holman, Zachary C.

    2015-08-14

    With this study, amorphous silicon enables the fabrication of very high-efficiency crystalline-silicon-based solar cells due to its combination of excellent passivation of the crystalline silicon surface and permeability to electrical charges. Yet, amongst other limitations, the passivation it provides degrades upon high-temperature processes, limiting possible post-deposition fabrication possibilities (e.g., forcing the use of low-temperature silver pastes). We investigate the potential use of intrinsic amorphous silicon carbide passivating layers to sidestep this issue. The passivation obtained using device-relevant stacks of intrinsic amorphous silicon carbide with various carbon contents and doped amorphous silicon are evaluated, and their stability upon annealing assessed, amorphous silicon carbide being shown to surpass amorphous silicon for temperatures above 300C. We demonstrate open-circuit voltage values over 700 mV for complete cells, and an improved temperature stability for the open-circuit voltage. Transport of electrons and holes across the hetero-interface is studied with complete cells having amorphous silicon carbide either on the hole-extracting side or on the electron-extracting side, and a better transport of holes than of electrons is shown. Also, due to slightly improved transparency, complete solar cells using an amorphous silicon carbide passivation layer on the hole-collecting side are demonstrated to show slightly better performances even prior to annealing than obtained with a standard amorphous silicon layer.

  9. Amorphous silicon carbide passivating layers for crystalline-silicon-based heterojunction solar cells

    SciTech Connect (OSTI)

    Boccard, Mathieu; Holman, Zachary C.

    2015-08-14

    With this study, amorphous silicon enables the fabrication of very high-efficiency crystalline-silicon-based solar cells due to its combination of excellent passivation of the crystalline silicon surface and permeability to electrical charges. Yet, amongst other limitations, the passivation it provides degrades upon high-temperature processes, limiting possible post-deposition fabrication possibilities (e.g., forcing the use of low-temperature silver pastes). We investigate the potential use of intrinsic amorphous silicon carbide passivating layers to sidestep this issue. The passivation obtained using device-relevant stacks of intrinsic amorphous silicon carbide with various carbon contents and doped amorphous silicon are evaluated, and their stability upon annealing assessed, amorphous silicon carbide being shown to surpass amorphous silicon for temperatures above 300°C. We demonstrate open-circuit voltage values over 700 mV for complete cells, and an improved temperature stability for the open-circuit voltage. Transport of electrons and holes across the hetero-interface is studied with complete cells having amorphous silicon carbide either on the hole-extracting side or on the electron-extracting side, and a better transport of holes than of electrons is shown. Also, due to slightly improved transparency, complete solar cells using an amorphous silicon carbide passivation layer on the hole-collecting side are demonstrated to show slightly better performances even prior to annealing than obtained with a standard amorphous silicon layer.

  10. Amorphous silicon materials and solar cells

    SciTech Connect (OSTI)

    Stafford, B.L. )

    1991-01-01

    An International Meeting on Stability of Amorphous Silicon Materials and Solar Cells was held in Denver, CO on February 20--22, 1991. The main objectives of the meeting were to bring to light-and stimulate discussion on-recent advances in (1) understanding the underlying mechanisms of light-induced instability and (2) engineering approaches to stable solar cells. Several of the experimental and theoretical papers presented here, particularly those regarding low-hydrogen-content materials, give cause for optimism that the performance may finally be yielding to worldwide concerted efforts to understand and mitigate it. The four main topics discussed are modeling metastability, experimental data and model verification, materials studies, and solar cell studies.

  11. Direct-patterned optical waveguides on amorphous silicon films

    DOE Patents [OSTI]

    Vernon, Steve; Bond, Tiziana C.; Bond, Steven W.; Pocha, Michael D.; Hau-Riege, Stefan

    2005-08-02

    An optical waveguide structure is formed by embedding a core material within a medium of lower refractive index, i.e. the cladding. The optical index of refraction of amorphous silicon (a-Si) and polycrystalline silicon (p-Si), in the wavelength range between about 1.2 and about 1.6 micrometers, differ by up to about 20%, with the amorphous phase having the larger index. Spatially selective laser crystallization of amorphous silicon provides a mechanism for controlling the spatial variation of the refractive index and for surrounding the amorphous regions with crystalline material. In cases where an amorphous silicon film is interposed between layers of low refractive index, for example, a structure comprised of a SiO.sub.2 substrate, a Si film and an SiO.sub.2 film, the formation of guided wave structures is particularly simple.

  12. Thin film tritium dosimetry

    DOE Patents [OSTI]

    Moran, Paul R.

    1976-01-01

    The present invention provides a method for tritium dosimetry. A dosimeter comprising a thin film of a material having relatively sensitive RITAC-RITAP dosimetry properties is exposed to radiation from tritium, and after the dosimeter has been removed from the source of the radiation, the low energy electron dose deposited in the thin film is determined by radiation-induced, thermally-activated polarization dosimetry techniques.

  13. Multifunctional thin film surface

    DOE Patents [OSTI]

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

    2015-10-13

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

  14. RF Sputtering for preparing substantially pure amorphous silicon monohydride

    DOE Patents [OSTI]

    Jeffrey, Frank R.; Shanks, Howard R.

    1982-10-12

    A process for controlling the dihydride and monohydride bond densities in hydrogenated amorphous silicon produced by reactive rf sputtering of an amorphous silicon target. There is provided a chamber with an amorphous silicon target and a substrate therein with the substrate and the target positioned such that when rf power is applied to the target the substrate is in contact with the sputtering plasma produced thereby. Hydrogen and argon are fed to the chamber and the pressure is reduced in the chamber to a value sufficient to maintain a sputtering plasma therein, and then rf power is applied to the silicon target to provide a power density in the range of from about 7 watts per square inch to about 22 watts per square inch to sputter an amorphous silicon hydride onto the substrate, the dihydride bond density decreasing with an increase in the rf power density. Substantially pure monohydride films may be produced.

  15. Amorphous silicon carbide passivating layers for crystalline-silicon-based heterojunction solar cells

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Boccard, Mathieu; Holman, Zachary C.

    2015-08-14

    With this study, amorphous silicon enables the fabrication of very high-efficiency crystalline-silicon-based solar cells due to its combination of excellent passivation of the crystalline silicon surface and permeability to electrical charges. Yet, amongst other limitations, the passivation it provides degrades upon high-temperature processes, limiting possible post-deposition fabrication possibilities (e.g., forcing the use of low-temperature silver pastes). We investigate the potential use of intrinsic amorphous silicon carbide passivating layers to sidestep this issue. The passivation obtained using device-relevant stacks of intrinsic amorphous silicon carbide with various carbon contents and doped amorphous silicon are evaluated, and their stability upon annealing assessed, amorphousmore » silicon carbide being shown to surpass amorphous silicon for temperatures above 300°C. We demonstrate open-circuit voltage values over 700 mV for complete cells, and an improved temperature stability for the open-circuit voltage. Transport of electrons and holes across the hetero-interface is studied with complete cells having amorphous silicon carbide either on the hole-extracting side or on the electron-extracting side, and a better transport of holes than of electrons is shown. Also, due to slightly improved transparency, complete solar cells using an amorphous silicon carbide passivation layer on the hole-collecting side are demonstrated to show slightly better performances even prior to annealing than obtained with a standard amorphous silicon layer.« less

  16. Process for producing amorphous and crystalline silicon nitride

    DOE Patents [OSTI]

    Morgan, P.E.D.; Pugar, E.A.

    1985-11-12

    A process for producing amorphous or crystalline silicon nitride is disclosed which comprises reacting silicon disulfide ammonia gas at elevated temperature. In a preferred embodiment silicon disulfide in the form of whiskers'' or needles is heated at temperature ranging from about 900 C to about 1,200 C to produce silicon nitride which retains the whisker or needle morphological characteristics of the silicon disulfide. Silicon carbide, e.g. in the form of whiskers, also can be prepared by reacting substituted ammonia, e.g. methylamine, or a hydrocarbon containing active hydrogen-containing groups, such as ethylene, with silicon disulfide, at elevated temperature, e.g. 900 C. 6 figs.

  17. Process for producing amorphous and crystalline silicon nitride

    DOE Patents [OSTI]

    Morgan, Peter E. D.; Pugar, Eloise A.

    1985-01-01

    A process for producing amorphous or crystalline silicon nitride is disclosed which comprises reacting silicon disulfide ammonia gas at elevated temperature. In a preferred embodiment silicon disulfide in the form of "whiskers" or needles is heated at temperature ranging from about 900.degree. C. to about 1200.degree. C. to produce silicon nitride which retains the whisker or needle morphological characteristics of the silicon disulfide. Silicon carbide, e.g. in the form of whiskers, also can be prepared by reacting substituted ammonia, e.g. methylamine, or a hydrocarbon containing active hydrogen-containing groups, such as ethylene, with silicon disulfide, at elevated temperature, e.g. 900.degree. C.

  18. Amorphous silicon passivated contacts for diffused junction silicon solar cells

    SciTech Connect (OSTI)

    Bullock, J. Yan, D.; Wan, Y.; Cuevas, A.; Demaurex, B.; Hessler-Wyser, A.; De Wolf, S.

    2014-04-28

    Carrier recombination at the metal contacts is a major obstacle in the development of high-performance crystalline silicon homojunction solar cells. To address this issue, we insert thin intrinsic hydrogenated amorphous silicon [a-Si:H(i)] passivating films between the dopant-diffused silicon surface and aluminum contacts. We find that with increasing a-Si:H(i) interlayer thickness (from 0 to 16?nm) the recombination loss at metal-contacted phosphorus (n{sup +}) and boron (p{sup +}) diffused surfaces decreases by factors of ?25 and ?10, respectively. Conversely, the contact resistivity increases in both cases before saturating to still acceptable values of ? 50 m? cm{sup 2} for n{sup +} and ?100 m? cm{sup 2} for p{sup +} surfaces. Carrier transport towards the contacts likely occurs by a combination of carrier tunneling and aluminum spiking through the a-Si:H(i) layer, as supported by scanning transmission electron microscopyenergy dispersive x-ray maps. We explain the superior contact selectivity obtained on n{sup +} surfaces by more favorable band offsets and capture cross section ratios of recombination centers at the c-Si/a-Si:H(i) interface.

  19. NMR characterization of thin films

    DOE Patents [OSTI]

    Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2010-06-15

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  20. NMR characterization of thin films

    DOE Patents [OSTI]

    Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2008-11-25

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  1. Method of producing solution-derived metal oxide thin films

    DOE Patents [OSTI]

    Boyle, Timothy J.; Ingersoll, David

    2000-01-01

    A method of preparing metal oxide thin films by a solution method. A .beta.-metal .beta.-diketonate or carboxylate compound, where the metal is selected from groups 8, 9, 10, 11, and 12 of the Periodic Table, is solubilized in a strong Lewis base to form a homogeneous solution. This precursor solution forms within minutes and can be deposited on a substrate in a single layer or a multiple layers to form a metal oxide thin film. The substrate with the deposited thin film is heated to change the film from an amorphous phase to a ceramic metal oxide and cooled.

  2. Thin film photovoltaic cell

    DOE Patents [OSTI]

    Meakin, John D.; Bragagnolo, Julio

    1982-01-01

    A thin film photovoltaic cell having a transparent electrical contact and an opaque electrical contact with a pair of semiconductors therebetween includes utilizing one of the electrical contacts as a substrate and wherein the inner surface thereof is modified by microroughening while being macro-planar.

  3. Epitaxial thin films

    DOE Patents [OSTI]

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

    2006-04-25

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

  4. Amorphous Silicon Carbide Passivating Layers to Enable Higher Processing Temperature in Crystalline Silicon Heterojunction Solar Cells

    SciTech Connect (OSTI)

    Boccard, Mathieu; Holman, Zachary

    2015-04-06

    "Very efficient crystalline silicon (c-Si) solar cells have been demonstrated when thin layers of intrinsic and doped hydrogenated amorphous silicon (a-Si:H) are used for passivation and carrier selectivity in a heterojunction device. One limitation of this device structure is the (parasitic) absorption in the front passivation/collection a-Si:H layers; another is the degradation of the a-Si:H-based passivation upon temperature, limiting the post-processes to approximately 200°C thus restricting the contacting possibilities and potential tandem device fabrication. To alleviate these two limitations, we explore the potential of amorphous silicon carbide (a-SiC:H), a widely studied material in use in standard a-Si:H thin-film solar cells, which is known for its wider bandgap, increased hydrogen content and stronger hydrogen bonding compared to a-Si:H. We study the surface passivation of solar-grade textured n-type c-Si wafers for symmetrical stacks of 10-nm-thick intrinsic a-SiC:H with various carbon content followed by either p-doped or n-doped a-Si:H (referred to as i/p or i/n stacks). For both doping types, passivation (assessed through carrier lifetime measurements) is degraded by increasing the carbon content in the intrinsic a-SiC:H layer. Yet, this hierarchy is reversed after annealing at 350°C or more due to drastic passivation improvements upon annealing when an a-SiC:H layer is used. After annealing at 350°C, lifetimes of 0.4 ms and 2.0 ms are reported for i/p and i/n stacks, respectively, when using an intrinsic a-SiC:H layer with approximately 10% of carbon (initial lifetimes of 0.3 ms and 0.1 ms, respectively, corresponding to a 30% and 20-fold increase, respectively). For stacks of pure a-Si:H material the lifetimes degrade from 1.2 ms and 2.0 ms for i/p and i/n stacks, respectively, to less than 0.1 ms and 1.1 ms (12-fold and 2-fold decrease, respectively). For complete solar cells using pure a-Si:H i/p and i/n stacks, the open-circuit voltage (Voc

  5. Thin-film optical initiator

    DOE Patents [OSTI]

    Erickson, Kenneth L.

    2001-01-01

    A thin-film optical initiator having an inert, transparent substrate, a reactive thin film, which can be either an explosive or a pyrotechnic, and a reflective thin film. The resultant thin-film optical initiator system also comprises a fiber-optic cable connected to a low-energy laser source, an output charge, and an initiator housing. The reactive thin film, which may contain very thin embedded layers or be a co-deposit of a light-absorbing material such as carbon, absorbs the incident laser light, is volumetrically heated, and explodes against the output charge, imparting about 5 to 20 times more energy than in the incident laser pulse.

  6. Rechargeable Thin-film Lithium Batteries

    DOE R&D Accomplishments [OSTI]

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

    1993-08-01

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

  7. Thin film superconductor magnetic bearings

    DOE Patents [OSTI]

    Weinberger, Bernard R.

    1995-12-26

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

  8. Effect of Dual-Function Nano-Structured Silicon Oxide Thin Film on Multi-Junction Solar Cells

    SciTech Connect (OSTI)

    Yan, B.; Sivec, L.; Yue, G.; Jiang, C. S.; Yang, J.; Guha, S.

    2011-01-01

    We present our recent study of using nano-structured hydrogenated silicon oxide films (nc-SiO{sub x}:H) as a dual-function layer in multi-junction solar cells. The nc-SiO{sub x}:H films were deposited using very high frequency glow discharge of a SiH{sub 4} (or Si{sub 2}H{sub 6}), CO{sub 2}, PH{sub 3}, and H{sub 2} gas mixture. By optimizing deposition parameters, we obtained 'dual function' nc-SiO{sub x}:H material characterized by a conductivity suitable for use as an n layer and optical properties suitable for use as an inter-reflection layer. We tested the nc-SiO{sub x}:H by replacing the normal n-type material in the tunnel junction of a multi-junction structure. The advantage of the dual-function nc-SiO{sub x}:H layer is twofold; one is to simplify the cell structure, and the other is to reduce any optical loss associated with the inter-reflection layer. Quantum efficiency measurements show the gain in top cell current is equal to or greater than the loss in bottom cell current for a-Si:H/nc-Si:H structures. In addition, a thinner a-Si:H top cell with the nc-SiO{sub x}:H n layer improves the top-cell stability, thereby providing higher stabilized solar cell efficiency. We also used the dual-function layer between the middle and the bottom cells in a-Si:H/a-SiGe:H/nc-Si:H triple-junction structures. The gain in the middle cell current is {approx}1.0 mA/cm{sup 2}, leading to an initial active-area efficiency of 14.8%.

  9. High-Efficiency Amorphous Silicon Alloy Based Solar Cells and Modules; Final Technical Progress Report, 30 May 2002--31 May 2005

    SciTech Connect (OSTI)

    Guha, S.; Yang, J.

    2005-10-01

    The principal objective of this R&D program is to expand, enhance, and accelerate knowledge and capabilities for development of high-efficiency hydrogenated amorphous silicon (a-Si:H) and amorphous silicon-germanium alloy (a-SiGe:H) related thin-film multijunction solar cells and modules with low manufacturing cost and high reliability. Our strategy has been to use the spectrum-splitting triple-junction structure, a-Si:H/a-SiGe:H/a-SiGe:H, to improve solar cell and module efficiency, stability, and throughput of production. The methodology used to achieve the objectives included: (1) explore the highest stable efficiency using the triple-junction structure deposited using RF glow discharge at a low rate, (2) fabricate the devices at a high deposition rate for high throughput and low cost, and (3) develop an optimized recipe using the R&D batch large-area reactor to help the design and optimization of the roll-to-roll production machines. For short-term goals, we have worked on the improvement of a-Si:H and a-SiGe:H alloy solar cells. a-Si:H and a-SiGe:H are the foundation of current a-Si:H based thin-film photovoltaic technology. Any improvement in cell efficiency, throughput, and cost reduction will immediately improve operation efficiency of our manufacturing plant, allowing us to further expand our production capacity.

  10. Thin film composite electrolyte

    DOE Patents [OSTI]

    Schucker, Robert C. (The Woodlands, TX)

    2007-08-14

    The invention is a thin film composite solid (and a means for making such) suitable for use as an electrolyte, having a first layer of a dense, non-porous conductive material; a second layer of a porous ionic conductive material; and a third layer of a dense non-porous conductive material, wherein the second layer has a Coefficient of thermal expansion within 5% of the coefficient of thermal expansion of the first and third layers.

  11. Effective interface state effects in hydrogenated amorphous-crystalline silicon heterostructures using ultraviolet laser photocarrier radiometry

    SciTech Connect (OSTI)

    Melnikov, A.; Mandelis, A.; Halliop, B.; Kherani, N. P.

    2013-12-28

    Ultraviolet photocarrier radiometry (UV-PCR) was used for the characterization of thin-film (nanolayer) intrinsic hydrogenated amorphous silicon (i-a-Si:H) on c-Si. The small absorption depth (approximately 10?nm at 355?nm laser excitation) leads to strong influence of the nanolayer parameters on the propagation and recombination of the photocarrier density wave (CDW) within the layer and the substrate. A theoretical PCR model including the presence of effective interface carrier traps was developed and used to evaluate the transport parameters of the substrate c-Si as well as those of the i-a-Si:H nanolayer. Unlike conventional optoelectronic characterization methods such as photoconductance, photovoltage, and photoluminescence, UV-PCR can be applied to more complete quantitative characterization of a-Si:H/c-Si heterojunction solar cells, including transport properties and defect structures. The quantitative results elucidate the strong effect of a front-surface passivating nanolayer on the transport properties of the entire structure as the result of effective a-Si:H/c-Si interface trap neutralization through occupation. A further dramatic improvement of those properties with the addition of a back-surface passivating nanolayer is observed and interpreted as the result of the interaction of the increased excess bulk CDW with, and more complete occupation and neutralization of, effective front interface traps.

  12. Flexoelectricity in barium strontium titanate thin film

    SciTech Connect (OSTI)

    Kwon, Seol Ryung; Huang, Wenbin; Yuan, Fuh-Gwo; Jiang, Xiaoning; Shu, Longlong; Maria, Jon-Paul

    2014-10-06

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

  13. Transmissive metallic contact for amorphous silicon solar cells

    DOE Patents [OSTI]

    Madan, A.

    1984-11-29

    A transmissive metallic contact for amorphous silicon semiconductors includes a thin layer of metal, such as aluminum or other low work function metal, coated on the amorphous silicon with an antireflective layer coated on the metal. A transparent substrate, such as glass, is positioned on the light reflective layer. The metallic layer is preferably thin enough to transmit at least 50% of light incident thereon, yet thick enough to conduct electricity. The antireflection layer is preferably a transparent material that has a refractive index in the range of 1.8 to 2.2 and is approximately 550A to 600A thick.

  14. The origin of white luminescence from silicon oxycarbide thin...

    Office of Scientific and Technical Information (OSTI)

    origin of white luminescence from silicon oxycarbide thin films Citation Details In-Document Search Title: The origin of white luminescence from silicon oxycarbide thin films ...

  15. Laterally inherently thin amorphous-crystalline silicon heterojunction photovoltaic cell

    SciTech Connect (OSTI)

    Chowdhury, Zahidur R. Kherani, Nazir P.

    2014-12-29

    This article reports on an amorphous-crystalline silicon heterojunction photovoltaic cell concept wherein the heterojunction regions are laterally narrow and distributed amidst a backdrop of well-passivated crystalline silicon surface. The localized amorphous-crystalline silicon heterojunctions consisting of the laterally thin emitter and back-surface field regions are precisely aligned under the metal grid-lines and bus-bars while the remaining crystalline silicon surface is passivated using the recently proposed facile grown native oxide–plasma enhanced chemical vapour deposited silicon nitride passivation scheme. The proposed cell concept mitigates parasitic optical absorption losses by relegating amorphous silicon to beneath the shadowed metallized regions and by using optically transparent passivation layer. A photovoltaic conversion efficiency of 13.6% is obtained for an untextured proof-of-concept cell illuminated under AM 1.5 global spectrum; the specific cell performance parameters are V{sub OC} of 666 mV, J{sub SC} of 29.5 mA-cm{sup −2}, and fill-factor of 69.3%. Reduced parasitic absorption, predominantly in the shorter wavelength range, is confirmed with external quantum efficiency measurement.

  16. Thin film hydrogen sensor

    DOE Patents [OSTI]

    Lauf, Robert J.; Hoffheins, Barbara S.; Fleming, Pamela H.

    1994-01-01

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed.

  17. Thin film photovoltaic device

    DOE Patents [OSTI]

    Catalano, Anthony W.; Bhushan, Manjul

    1982-01-01

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids.

  18. Thin film photovoltaic device

    DOE Patents [OSTI]

    Catalano, A.W.; Bhushan, M.

    1982-08-03

    A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids. 5 figs.

  19. Yttria-stabilized zirconia buffered silicon to optimize in-plane electrical conductivity of [Ca{sub 2}CoO{sub 3}]{sub 0.62}[CoO{sub 2}] thin films

    SciTech Connect (OSTI)

    Kraus, T.; Griesser, A.; Klein, O.; Fischer, M.; Schreck, M.; Karl, H.

    2014-05-05

    The monolithic integration of thermoelectric generators and magnetoresistive functionality on the basis of misfit cobaltate [Ca{sub 2}CoO{sub 3}]{sub 0.62}[CoO{sub 2}] thin films into silicon technology is a prerequisite for their application in miniaturized electric circuits. Here, we report on [Ca{sub 2}CoO{sub 3}]{sub 0.62}[CoO{sub 2}] thin films grown by pulsed laser deposition on (001)-silicon with a thin epitaxial yttria-stabilized zirconia (YSZ) buffer layer. X-ray diffraction and cross-sectional high resolution transmission electron microscopy analysis reveal that high quality c-axis oriented heteroepitaxial [Ca{sub 2}CoO{sub 3}]{sub 0.62}[CoO{sub 2}] films with a 12-fold in-plane rotational symmetry can be grown, which exhibit remarkable lower electrical resistivity compared to those with random in-plane orientation. This result is explained by energetically preferred epitaxial growth directions of the pseudo hexagonal [CoO{sub 2}] sublayer in monoclinic [Ca{sub 2}CoO{sub 3}]{sub 0.62}[CoO{sub 2}] onto the cubic (001)-YSZ surface leading to a highly symmetric in-plane mutual orientation of the charge transporting CoO{sub 2} sublayer domains.

  20. Deposition of device quality low H content, amorphous silicon films

    DOE Patents [OSTI]

    Mahan, Archie H.; Carapella, Jeffrey C.; Gallagher, Alan C.

    1995-01-01

    A high quality, low hydrogen content, hydrogenated amorphous silicon (a-Si:H) film is deposited by passing a stream of silane gas (SiH.sub.4) over a high temperature, 2000.degree. C., tungsten (W) filament in the proximity of a high temperature, 400.degree. C., substrate within a low pressure, 8 mTorr, deposition chamber. The silane gas is decomposed into atomic hydrogen and silicon, which in turn collides preferably not more than 20-30 times before being deposited on the hot substrate. The hydrogenated amorphous silicon films thus produced have only about one atomic percent hydrogen, yet have device quality electrical, chemical, and structural properties, despite this lowered hydrogen content.

  1. Deposition of device quality low H content, amorphous silicon films

    DOE Patents [OSTI]

    Mahan, A.H.; Carapella, J.C.; Gallagher, A.C.

    1995-03-14

    A high quality, low hydrogen content, hydrogenated amorphous silicon (a-Si:H) film is deposited by passing a stream of silane gas (SiH{sub 4}) over a high temperature, 2,000 C, tungsten (W) filament in the proximity of a high temperature, 400 C, substrate within a low pressure, 8 mTorr, deposition chamber. The silane gas is decomposed into atomic hydrogen and silicon, which in turn collides preferably not more than 20--30 times before being deposited on the hot substrate. The hydrogenated amorphous silicon films thus produced have only about one atomic percent hydrogen, yet have device quality electrical, chemical, and structural properties, despite this lowered hydrogen content. 7 figs.

  2. Thin film photovoltaic device with multilayer substrate

    DOE Patents [OSTI]

    Catalano, Anthony W.; Bhushan, Manjul

    1984-01-01

    A thin film photovoltaic device which utilizes at least one compound semiconductor layer chosen from Groups IIB and VA of the Periodic Table is formed on a multilayer substrate The substrate includes a lowermost support layer on which all of the other layers of the device are formed. Additionally, an uppermost carbide or silicon layer is adjacent to the semiconductor layer. Below the carbide or silicon layer is a metal layer of high conductivity and expansion coefficient equal to or slightly greater than that of the semiconductor layer.

  3. Thin film ion conducting coating

    DOE Patents [OSTI]

    Goldner, Ronald B.; Haas, Terry; Wong, Kwok-Keung; Seward, George

    1989-01-01

    Durable thin film ion conducting coatings are formed on a transparent glass substrate by the controlled deposition of the mixed oxides of lithium:tantalum or lithium:niobium. The coatings provide durable ion transport sources for thin film solid state storage batteries and electrochromic energy conservation devices.

  4. Innovative Thin Films LLC | Open Energy Information

    Open Energy Info (EERE)

    Thin Films LLC Place: Toledo, Ohio Zip: 43607 Product: Provider of altnernative energy thin film deposition technology. Coordinates: 46.440613, -122.847838 Show Map Loading...

  5. Thin Film Solar Technologies | Open Energy Information

    Open Energy Info (EERE)

    help OpenEI by expanding it. Thin Film Solar Technologies is a company located in South Africa . References "Thin Film Solar Technologies" Retrieved from "http:...

  6. High-Efficiency Polycrystalline CdTe Thin-Film Solar Cells with an Oxygenated Amorphous CdS (a-CdS:O) Window Layer: Preprint

    SciTech Connect (OSTI)

    Wu, X.; Dhere, R. G.; Yan, Y.; Romero, M. J.; Zhang, Y.; Zhou, J.; DeHart, C.; Duda, A.; Perkins, C.; To, B.

    2002-05-01

    In the conventional CdS/CdTe device structure, the poly-CdS window layer has a bandgap of {approx}2.4 eV, which causes absorption in the short-wavelength region. Higher short-circuit current densities (Jsc) can be achieved by reducing the CdS thickness, but this can adversely impact device open-circuit voltage (Voc) and fill factor (FF). Also, poly-CdS film has about 10% lattice mismatch related to the CdTe film, which limits the improvement of device Voc and FF. In this paper, we report a novel window material: oxygenated amorphous CdS film (a-CdS:O) prepared at room temperature by rf sputtering. The a-CdS:O film has a higher optical bandgap (2.5-3.1 eV) than the poly-CdS film and an amorphous structure. The preliminary device results have demonstrated that Jsc of the CdTe device can be greatly improved while maintaining higher Voc and FF. We have fabricated a CdTe cell demonstrating an NREL-confirmed Jsc of 25.85 mA/cm2 and a total-area efficiency of 15.4%.

  7. Ferromagnetic thin films

    DOE Patents [OSTI]

    Krishnan, K.M.

    1994-12-20

    A ferromagnetic [delta]-Mn[sub 1[minus]x]Ga[sub x] thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4[+-]0.05. 7 figures.

  8. Thin film hydrogen sensor

    DOE Patents [OSTI]

    Lauf, R.J.; Hoffheins, B.S.; Fleming, P.H.

    1994-11-22

    A hydrogen sensor element comprises an essentially inert, electrically-insulating substrate having a thin-film metallization deposited thereon which forms at least two resistors on the substrate. The metallization comprises a layer of Pd or a Pd alloy for sensing hydrogen and an underlying intermediate metal layer for providing enhanced adhesion of the metallization to the substrate. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors, and at least one of the resistors is left uncovered. The difference in electrical resistances of the covered resistor and the uncovered resistor is related to hydrogen concentration in a gas to which the sensor element is exposed. 6 figs.

  9. Structure disorder degree of polysilicon thin films grown by different processing: Constant C from Raman spectroscopy

    SciTech Connect (OSTI)

    Wang, Quan; Zhang, Yanmin; Hu, Ran; Ren, Naifei; Ge, Daohan

    2013-11-14

    Flat, low-stress, boron-doped polysilicon thin films were prepared on single crystalline silicon substrates by low pressure chemical vapor deposition. It was found that the polysilicon films with different deposition processing have different microstructure properties. The confinement effect, tensile stresses, defects, and the Fano effect all have a great influence on the line shape of Raman scattering peak. But the effect results are different. The microstructure and the surface layer are two important mechanisms dominating the internal stress in three types of polysilicon thin films. For low-stress polysilicon thin film, the tensile stresses are mainly due to the change of microstructure after thermal annealing. But the tensile stresses in flat polysilicon thin film are induced by the silicon carbide layer at surface. After the thin film doped with boron atoms, the phenomenon of the tensile stresses increasing can be explained by the change of microstructure and the increase in the content of silicon carbide. We also investigated the disorder degree states for three polysilicon thin films by analyzing a constant C. It was found that the disorder degree of low-stress polysilicon thin film larger than that of flat and boron-doped polysilicon thin films due to the phase transformation after annealing. After the flat polysilicon thin film doped with boron atoms, there is no obvious change in the disorder degree and the disorder degree in some regions even decreases.

  10. High Thermal Conductivity of a Hydrogenated Amorphous Silicon Film

    SciTech Connect (OSTI)

    Liu, X.; Feldman, J. L.; Cahill, D. G.; Crandall, R. S.; Bernstein, N.; Photiadis, D. M.; Mehl, M. J.; Papaconstantopoulos, D. A.

    2009-01-23

    We measured the thermal conductivity {kappa} of an 80 {micro}m thick hydrogenated amorphous silicon film prepared by hot-wire chemical-vapor deposition with the 3{omega} (80-300 K) and the time-domain thermoreflectance (300 K) methods. The {kappa} is higher than any of the previous temperature dependent measurements and shows a strong phonon mean free path dependence. We also applied a Kubo based theory using a tight-binding method on three 1000 atom continuous random network models. The theory gives higher {kappa} for more ordered models, but not high enough to explain our results, even after extrapolating to lower frequencies with a Boltzmann approach. Our results show that this material is more ordered than any amorphous silicon previously studied.

  11. The reliability and stability of multijunction amorphous silicon PV modules

    SciTech Connect (OSTI)

    Carlson, D.E.

    1995-11-01

    Solarex is developing a manufacturing process for the commercial production of 8 ft{sup 2} multijunction amorphous silicon (a-Si) PV modules starting in 1996. The device structure used in these multijunction modules is: glass/textured tin oxide/p-i-n/p-i-n/ZnO/Al/EVA/Tedlar where the back junction of the tandem structure contains an amorphous silicon germanium alloy. As an interim step, 4 ft{sup 2} multijunction modules have been fabricated in a pilot production mode over the last several months. The distribution of initial conversion efficiencies for an engineering run of 67 modules (4 ft{sup 2}) is shown. Measurements recently performed at NREL indicate that the actual efficiencies are about 5% higher than those shown, and thus exhibit an average initial conversion efficiency of about 9.5%. The data indicates that the process is relatively robust since there were no modules with initial efficiencies less than 7.5%.

  12. Micro/nano devices fabricated from Cu-Hf thin films

    DOE Patents [OSTI]

    Luber, Erik J; Ophus, Colin; Mitlin, David; Olsen, Brian; Harrower, Christopher; Radmilovi, Velimir

    2013-06-04

    An all-metal microdevice or nanodevice such as an atomic force microscope probe is manufactured from a copper-hafnium alloy thin film having an x-ray amorphous microstructure.

  13. Deposition of device quality, low hydrogen content, amorphous silicon films by hot filament technique using "safe" silicon source gas

    DOE Patents [OSTI]

    Mahan, Archie Harvin; Molenbroek, Edith C.; Nelson, Brent P.

    1998-01-01

    A method of producing hydrogenated amorphous silicon on a substrate by flowing a stream of safe (diluted to less than 1%) silane gas past a heated filament.

  14. Efficient nanorod-based amorphous silicon solar cells with advanced light trapping

    SciTech Connect (OSTI)

    Kuang, Y.; Lare, M. C. van; Polman, A.; Veldhuizen, L. W.; Schropp, R. E. I.; Rath, J. K.

    2015-11-14

    We present a simple, low-cost, and scalable approach for the fabrication of efficient nanorod-based solar cells. Templates with arrays of self-assembled ZnO nanorods with tunable morphology are synthesized by chemical bath deposition using a low process temperature at 80 °C. The nanorod templates are conformally coated with hydrogenated amorphous silicon light absorber layers of 100 nm and 200 nm thickness. An initial efficiency of up to 9.0% is achieved for the optimized design. External quantum efficiency measurements on the nanorod cells show a substantial photocurrent enhancement both in the red and the blue parts of the solar spectrum. Key insights in the light trapping mechanisms in these arrays are obtained via a combination of three-dimensional finite-difference time-domain simulations, optical absorption, and external quantum efficiency measurements. Front surface patterns enhance the light incoupling in the blue, while rear side patterns lead to enhanced light trapping in the red. The red response in the nanorod cells is limited by absorption in the patterned Ag back contact. With these findings, we develop and experimentally realize a further advanced design with patterned front and back sides while keeping the Ag reflector flat, showing significantly enhanced scattering from the back reflector with reduced parasitic absorption in the Ag and thus higher photocurrent generation. Many of the findings in this work can serve to provide insights for further optimization of nanostructures for thin-film solar cells in a broad range of materials.

  15. Rechargeable thin-film lithium batteries

    SciTech Connect (OSTI)

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

    1993-09-01

    Rechargeable thin-film batteries consisting of lithium metal anodes, an amorphous inorganic electrolyte, and cathodes of lithium intercalation compounds have been fabricated and characterized. These include Li-TiS{sub 2}, Li-V{sub 2}O{sub 5}, and Li-Li{sub x}Mn{sub 2}O{sub 4} cells with open circuit voltages at full charge of about 2.5 V, 3.7 V, and 4.2 V, respectively. The realization of these robust cells, which can be cycled thousands of times, was possible because of the stability of the amorphous lithium electrolyte, lithium phosphorus oxynitride. This material has a typical composition of Li{sub 2.9}PO{sub 3.3}N{sub 0.46}and a conductivity at 25 C of 2 {mu}S/cm. The thin-film cells have been cycled at 100% depth of discharge using current densities of 5 to 100 {mu}A/cm{sup 2}. Over most of the charge-discharge range, the internal resistance appears to be dominated by the cathode, and the major source of the resistance is the diffusion of Li{sup +} ions from the electrolyte into the cathode. Chemical diffusion coefficients were determined from ac impedance measurements.

  16. Thin-film Rechargeable Lithium Batteries

    DOE R&D Accomplishments [OSTI]

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

    1993-11-01

    Rechargeable thin films batteries with lithium metal anodes, an amorphous inorganic electrolyte, and cathodes of lithium intercalation compounds have been fabricated and characterized. The cathodes include TiS{sub 2}, the {omega} phase of V{sub 2}O{sub 5}, and the cubic spinel Li{sub x}Mn{sub 2}O{sub 4} with open circuit voltages at full charge of about 2.5 V, 3.7 V, and 4.2 V, respectively. The development of these robust cells, which can be cycled thousands of times, was possible because of the stability of the amorphous lithium electrolyte, lithium phosphorus oxynitride. This material has a typical composition of Li{sub 2.9}PO{sub 3.3}N{sub 0.46} and a conductivity at 25 C of 2 {mu}S/cm. Thin film cells have been cycled at 100% depth of discharge using current densities of 2 to 100 {mu}A/cm{sup 2}. The polarization resistance of the cells is due to the slow insertion rate of Li{sup +} ions into the cathode. Chemical diffusion coefficients for Li{sup +} ions in the three types of cathodes have been estimated from the analysis of ac impedance measurements.

  17. Enhanced electrical and magnetic properties in La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films deposited on CaTiO{sub 3}-buffered silicon substrates

    SciTech Connect (OSTI)

    Adamo, C.; Méchin, L.; Guillet, B.; Wu, S.; Routoure, J.-M.; Heeg, T.; Katz, M.; Pan, X. Q.; Mercone, S.; Schubert, J.; Zander, W.; Misra, R.; Schiffer, P.; and others

    2015-06-01

    We investigate the suitability of an epitaxial CaTiO{sub 3} buffer layer deposited onto (100) Si by reactive molecular-beam epitaxy (MBE) for the epitaxial integration of the colossal magnetoresistive material La{sub 0.7}Sr{sub 0.3}MnO{sub 3} with silicon. The magnetic and electrical properties of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} films deposited by MBE on CaTiO{sub 3}-buffered silicon (CaTiO{sub 3}/Si) are compared with those deposited on SrTiO{sub 3}-buffered silicon (SrTiO{sub 3}/Si). In addition to possessing a higher Curie temperature and a higher metal-to-insulator transition temperature, the electrical resistivity and 1/f noise level at 300 K are reduced by a factor of two in the heterostructure with the CaTiO{sub 3} buffer layer. These results are relevant to device applications of La{sub 0.7}Sr{sub 0.3}MnO{sub 3} thin films on silicon substrates.

  18. TEM characterization of nanodiamond thin films.

    SciTech Connect (OSTI)

    Qin, L.-C.; Zhou, D.; Krauss, A. R.; Gruen, D. M.; Chemistry

    1998-05-01

    The microstructure of thin films grown by microwave plasma-enhanced chemical vapor deposition (MPCVD) from fullerene C{sub 60} precursors has been characterized by scanning electron microscopy (SEM), selected-area electron diffraction (SAED), bright-field electron microscopy, high-resolution electron microscopy (HREM), and parallel electron energy loss spectroscopy (PEELS). The films are composed of nanosize crystallites of diamond, and no graphitic or amorphous phases were observed. The diamond crystallite size measured from lattice images shows that most grains range between 3-5 nm, reflecting a gamma distribution. SAED gave no evidence of either sp2-bonded glassy carbon or sp3-bonded diamondlike amorphous carbon. The sp2-bonded configuration found in PEELS was attributed to grain boundary carbon atoms, which constitute 5-10% of the total. Occasionally observed larger diamond grains tend to be highly faulted.

  19. Electron-beam-induced information storage in hydrogenated amorphous silicon devices

    DOE Patents [OSTI]

    Yacobi, B.G.

    1985-03-18

    A method for recording and storing information in a hydrogenated amorphous silicon device, comprising: depositing hydrogenated amorphous silicon on a substrate to form a charge collection device; and generating defects in the hydrogenated amorphous silicon device, wherein the defects act as recombination centers that reduce the lifetime of carriers, thereby reducing charge collection efficiency and thus in the charge collection mode of scanning probe instruments, regions of the hydrogenated amorphous silicon device that contain the defects appear darker in comparison to regions of the device that do not contain the defects, leading to a contrast formation for pattern recognition and information storage.

  20. Improved method of preparing p-i-n junctions in amorphous silicon semiconductors

    DOE Patents [OSTI]

    Madan, A.

    1984-12-10

    A method of preparing p/sup +/-i-n/sup +/ junctions for amorphous silicon semiconductors includes depositing amorphous silicon on a thin layer of trivalent material, such as aluminum, indium, or gallium at a temperature in the range of 200/sup 0/C to 250/sup 0/C. At this temperature, the layer of trivalent material diffuses into the amorphous silicon to form a graded p/sup +/-i junction. A layer of n-type doped material is then deposited onto the intrinsic amorphous silicon layer in a conventional manner to finish forming the p/sup +/-i-n/sup +/ junction.

  1. Structural origin of bulk molecular hydrogen in hydrogenated amorphous silicon

    SciTech Connect (OSTI)

    Liu, X.; Pohl, R.O.; Crandall, R.S.

    1999-07-01

    The elastic anomaly observed previously at the triple point of bulk molecular hydrogen in hydrogenated amorphous silicon films prepared by hot-wire chemical-vapor deposition has also been observed in deuterated films at the triple point of D{sub 2}. The origin of this anomaly has now been traced to bubbles formed at the crystalline-amorphous interface. An upper limit of the pressure in these bubbles at their formation temperature, 440 C, has been estimated to be 11 MPa, and is suggested to be a measure of the bonding strength between film and substrate at that temperature. Bubble formation after heat treatment at 400 C has also been observed in films prepared by plasma-enhanced chemical-vapor deposition. The internal friction anomalies resemble those observed previously in cold-worked hydrogenated iron where they have been interpreted through plastic deformation of solid hydrogen in voids.

  2. Thinner Film Silicon Solar Cells - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    thin film silicon solar cells with a potential increase in photon energy conversion of up to 20%, a significant improvement over conventional thin film photovoltaic technologies. ...

  3. Enhanced electrochemical etching of ion irradiated silicon by localized amorphization

    SciTech Connect (OSTI)

    Dang, Z. Y.; Breese, M. B. H.; Lin, Y.; Tok, E. S.; Vittone, E.

    2014-05-12

    A tailored distribution of ion induced defects in p-type silicon allows subsequent electrochemical anodization to be modified in various ways. Here we describe how a low level of lattice amorphization induced by ion irradiation influences anodization. First, it superposes a chemical etching effect, which is observable at high fluences as a reduced height of a micromachined component. Second, at lower fluences, it greatly enhances electrochemical anodization by allowing a hole diffusion current to flow to the exposed surface. We present an anodization model, which explains all observed effects produced by light ions such as helium and heavy ions such as cesium over a wide range of fluences and irradiation geometries.

  4. Properties of hydrogenated amorphous silicon produced at high temperature

    SciTech Connect (OSTI)

    Crandall, R.S.; Mahan, A.H.; Nelson, B. ); Vanecek, M. ); Balberg, I. )

    1992-12-01

    A comprehensive study of hydrogenated amorphous silicon ([ital a]-Si:H) deposited by hot wire and conventional glow discharge suggests that temperatures above the so called optimum 250 [degree]C substrate temperature can produce device-quality films. These films show enhanced transport properties and improved structural order. In addition we show that hot wire material can be produced with just as many hydrogen atoms as are needed to passivate most of the dangling bonds present in unhydrogenated [ital a]-Si:H.

  5. Cathodic deposition of amorphous alloys of silicon, carbon, and fluorine

    SciTech Connect (OSTI)

    Lee, C.H.; Kroger, F.A.

    1982-05-01

    Amorphous silicon containing fluorine and carbon, pure and doped with boron or phosphorus, was deposited cathodically from solutions of K/sub 2/SiF/sub 6/ in acetone with HF. The conditions for optimum deposition were determined, and the deposits were characterized by electron microprobe x-ray emission, electrical conductivity, and infrared absorption. Doping with phosphorus causes a change from p- to n-type semiconductor behavior, with a maximum of resistivity >10/sup 13/ /OMEGA/ cm at the compensation point. 48 refs.

  6. Low Cost Thin Film Building-Integrated Photovoltaic Systems

    SciTech Connect (OSTI)

    Dr. Subhendu Guha; Dr. Jeff Yang

    2012-05-25

    The goal of the program is to develop 'LOW COST THIN FILM BUILDING-INTEGRATED PV SYSTEMS'. Major focus was on developing low cost solution for the commercial BIPV and rooftop PV market and meet DOE LCOE goal for the commercial market segment of 9-12 cents/kWh for 2010 and 6-8 cents/kWh for 2015. We achieved the 2010 goal and were on track to achieve the 2015 goal. The program consists of five major tasks: (1) modules; (2) inverters and BOS; (3) systems engineering and integration; (4) deployment; and (5) project management and TPP collaborative activities. We successfully crossed all stage gates and surpassed all milestones. We proudly achieved world record stable efficiencies in small area cells (12.56% for 1cm2) and large area encapsulated modules (11.3% for 800 cm2) using a triple-junction amorphous silicon/nanocrystalline silicon/nanocrystalline silicon structure, confirmed by the National Renewable Energy Laboratory. We collaborated with two inverter companies, Solectria and PV Powered, and significantly reduced inverter cost. We collaborated with three universities (Syracuse University, University of Oregon, and Colorado School of Mines) and National Renewable Energy Laboratory, and improved understanding on nanocrystalline material properties and light trapping techniques. We jointly published 50 technical papers in peer-reviewed journals and International Conference Proceedings. We installed two 75kW roof-top systems, one in Florida and another in New Jersey demonstrating innovative designs. The systems performed satisfactorily meeting/exceeding estimated kWh/kW performance. The 50/50 cost shared program was a great success and received excellent comments from DOE Manager and Technical Monitor in the Final Review.

  7. Properties of zirconia thin films deposited by laser ablation

    SciTech Connect (OSTI)

    Cancea, V. N.; Filipescu, M.; Colceag, D.; Dinescu, M.; Mustaciosu, C.

    2013-11-13

    Zirconia thin films have been deposited by laser ablation of a ceramic ZrO{sub 2} target in vacuum or in oxygen background at 0.01 mbar. The laser beam generated by an ArF laser (λ=193 nm, ν=40 Hz) has been focalized on the target through a spherical lens at an incident angle of 45°. The laser fluence has been established to a value from 2.0 to 3.4 Jcm{sup −2}. A silicon (100) substrate has been placed parallel to the target, at a distance of 4 cm, and subsequently has been heated to temperatures ranging between 300 °C and 600 °C. Thin films morphology has been characterized by atomic force microscopy and secondary ion mass spectrometry. Biocompatibility of these thin films has been assessed by studying the cell attachment of L929 mouse fibroblasts.

  8. Uncooled thin film pyroelectric IR detector with aerogel thermal isolation

    SciTech Connect (OSTI)

    Ruffner, J.A.; Clem, P.G.; Tuttle, B.A. [and others

    1998-01-01

    Uncooled pyroelectric IR imaging systems, such as night vision goggles, offer important strategic advantages in battlefield scenarios and reconnaissance surveys. Until now, the current technology for fabricating these devices has been limited by low throughput and high cost which ultimately limit the availability of these sensor devices. We have developed and fabricated an alternative design for pyroelectric IR imaging sensors that utilizes a multilayered thin film deposition scheme to create a monolithic thin film imaging element on an active silicon substrate for the first time. This approach combines a thin film pyroelectric imaging element with a thermally insulating SiO{sub 2} aerogel thin film to produce a new type of uncooled IR sensor that offers significantly higher thermal, spatial, and temporal resolutions at a substantially lower cost per unit. This report describes the deposition, characterization and optimization of the aerogel thermal isolation layer and an appropriate pyroelectric imaging element. It also describes the overall integration of these components along with the appropriate planarization, etch stop, adhesion, electrode, and blacking agent thin film layers into a monolithic structure. 19 refs., 8 figs., 6 tabs.

  9. Direct Evidence of Phosphorus-Defect Complexes in n -Type Amorphous Silicon and Hydrogenated Amorphous Silicon

    SciTech Connect (OSTI)

    Petkov, M.P.; Weber, M.H.; Lynn, K.G.; Crandall, R.S.; Ghosh, V.J.

    1999-05-01

    We use positron annihilation spectroscopy (PAS) to identify the phosphorus-defect complex ({sup {asterisk}}D{sup {minus}}) in n -type hydrogenated amorphous Si (a -Si:H). The positrons are attracted and localized at the small open volume associated with the dangling bond defects. The radiation detected after annihilation gives a characteristic P signature, regarded as a {sup {asterisk}}D{sup {minus}} {open_quotes}fingerprint.{close_quotes} Additional evidence is obtained from a comparison to P-implanted amorphized Si, as well as from theoretical calculations. This work lays the foundation for PAS studies of impurity-defect related processes in a -Si:H. {copyright} {ital 1999} {ital The American Physical Society}

  10. Sputtered pin amorphous silicon semi-conductor device and method therefor

    DOE Patents [OSTI]

    Moustakas, Theodore D.; Friedman, Robert A.

    1983-11-22

    A high efficiency amorphous silicon PIN semi-conductor device is constructed by the sequential sputtering of N, I and P layers of amorphous silicon and at least one semi-transparent ohmic electrode. A method of construction produces a PIN device, exhibiting enhanced physical integrity and facilitates ease of construction in a singular vacuum system and vacuum pump down procedure.

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

    SciTech Connect (OSTI)

    Li, Qin; Song, Zhong Xiao; Ma, Fei E-mail: liyhemail@gmail.com; Li, Yan Huai E-mail: liyhemail@gmail.com; Xu, Ke Wei

    2015-03-15

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

  12. Electron-beam-induced information storage in hydrogenated amorphous silicon device

    DOE Patents [OSTI]

    Yacobi, Ben G.

    1986-01-01

    A method for recording and storing information in a hydrogenated amorphous silicon device, comprising: depositing hydrogenated amorphous silicon on a substrate to form a charge-collection device; and generating defects in the hydrogenated amorphous silicon device, wherein the defects act as recombination centers that reduce the lifetime of carriers, thereby reducing charge-collection efficiency; and thus in the charge-collection mode of scanning probe instruments, regions of the hydrogenated amorphous silicon device that contain the defects appear darker in comparison to regions of the device that do not contain the defects, leading to a contrast formation for pattern recognition and information storage, in the device, which darkened areas can be restored to their original charge-collection efficiency by heating the hydrogenated amorphous silicon to a temperature of about 100.degree. C. to 250.degree. C. for a sufficient period of time to provide for such restoration.

  13. Highly featured amorphous silicon nanorod arrays for high-performance lithium-ion batteries

    SciTech Connect (OSTI)

    Soleimani-Amiri, Samaneh; Safiabadi Tali, Seied Ali; Azimi, Soheil; Sanaee, Zeinab; Mohajerzadeh, Shamsoddin

    2014-11-10

    High aspect-ratio vertical structures of amorphous silicon have been realized using hydrogen-assisted low-density plasma reactive ion etching. Amorphous silicon layers with the thicknesses ranging from 0.5 to 10 μm were deposited using radio frequency plasma enhanced chemical vapor deposition technique. Standard photolithography and nanosphere colloidal lithography were employed to realize ultra-small features of the amorphous silicon. The performance of the patterned amorphous silicon structures as a lithium-ion battery electrode was investigated using galvanostatic charge-discharge tests. The patterned structures showed a superior Li-ion battery performance compared to planar amorphous silicon. Such structures are suitable for high current Li-ion battery applications such as electric vehicles.

  14. Semiconductor-nanocrystal/conjugated polymer thin films

    DOE Patents [OSTI]

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

    2010-08-17

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

  15. Semiconductor-nanocrystal/conjugated polymer thin films

    DOE Patents [OSTI]

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

    2014-06-17

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

  16. Thin film-coated polymer webs

    DOE Patents [OSTI]

    Wenz, Robert P.; Weber, Michael F.; Arudi, Ravindra L.

    1992-02-04

    The present invention relates to thin film-coated polymer webs, and more particularly to thin film electronic devices supported upon a polymer web, wherein the polymer web is treated with a purifying amount of electron beam radiation.

  17. Thin film polymeric gel electrolytes

    DOE Patents [OSTI]

    Derzon, Dora K.; Arnold, Jr., Charles; Delnick, Frank M.

    1996-01-01

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

  18. Thin film polymeric gel electrolytes

    DOE Patents [OSTI]

    Derzon, D.K.; Arnold, C. Jr.; Delnick, F.M.

    1996-12-31

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

  19. Producing thin film photovoltaic modules with high integrity interconnects and dual layer contacts

    DOE Patents [OSTI]

    Jansen, Kai W.; Maley, Nagi

    2001-01-01

    High performance photovoltaic modules are produced with improved interconnects by a special process. Advantageously, the photovoltaic modules have a dual layer back (rear) contact and a front contact with at least one layer. The front contact and the inner layer of the back contact can comprise a transparent conductive oxide. The outer layer of the back contact can comprise a metal or metal oxide. The front contact can also have a dielectric layer. In one form, the dual layer back contact comprises a zinc oxide inner layer and an aluminum outer layer and the front contact comprises a tin oxide inner layer and a silicon dioxide dielectric outer layer. One or more amorphous silicon-containing thin film semiconductors can be deposited between the front and back contacts. The contacts can be positioned between a substrate and an optional superstrate. During production, the transparent conductive oxide layer of the front contact is scribed by a laser, then the amorphous silicon-containing semiconductors and inner layer of the dual layer back contact are simultaneously scribed and trenched (drilled) by the laser and the trench is subsequently filled with the same metal as the outer layer of the dual layer back contact to provide a superb mechanical and electrical interconnect between the front contact and the outer layer of the dual layer back contact. The outer layer of the dual layer back contact can then be scribed by the laser. For enhanced environmental protection, the photovoltaic modules can be encapsulated.

  20. Producing thin film photovoltaic modules with high integrity interconnects and dual layer contacts

    DOE Patents [OSTI]

    Jansen, Kai W.; Maley, Nagi

    2000-01-01

    High performance photovoltaic modules are produced with improved interconnects by a special process. Advantageously, the photovoltaic modules have a dual layer back (rear) contact and a front contact with at least one layer. The front contact and the inner layer of the back contact can comprise a transparent conductive oxide. The outer layer of the back contact can comprise a metal or metal oxide. The front contact can also have a dielectric layer. In one form, the dual layer back contact comprises a zinc oxide inner layer and an aluminum outer layer and the front contact comprises a tin oxide inner layer and a silicon dioxide dielectric outer layer. One or more amorphous silicon-containing thin film semiconductors can be deposited between the front and back contacts. The contacts can be positioned between a substrate and an optional superstrate. During production, the transparent conductive oxide layer of the front contact is scribed by a laser, then the amorphous silicon-containing semiconductors and inner layer of the dual layer back contact are simultaneously scribed and trenched (drilled) by the laser and the trench is subsequently filled with the same metal as the outer layer of the dual layer back contact to provide a superb mechanical and electrical interconnect between the front contact and the outer layer of the dual layer back contact. The outer layer of the dual layer back contact can then be scribed by the laser. For enhanced environmental protection, the photovoltaic modules can be encapsulated.

  1. Deposition of device quality, low hydrogen content, amorphous silicon films by hot filament technique using ``safe`` silicon source gas

    DOE Patents [OSTI]

    Mahan, A.H.; Molenbroek, E.C.; Nelson, B.P.

    1998-07-07

    A method is described for producing hydrogenated amorphous silicon on a substrate by flowing a stream of safe (diluted to less than 1%) silane gas past a heated filament. 7 figs.

  2. Research on stable, high-efficiency amorphous silicon multijunction modules

    SciTech Connect (OSTI)

    Ghosh, M.; DelCueto, J.: Kampas, F.; Xi, J. )

    1993-02-01

    This report describes results from the first phase of a three-phase contract for the development of stable, high-efficiency, same-band-gap, amorphous silicon (a-Si) multijunction photovoltaic (PV) modules. The program involved improving the properties of individual layers of semiconductor and non-semiconductor materials and small-area single-junction and multijunction devices, as well as the multijunction modules. The semiconductor materials research was performed on a-Si p, i, and n layers, and on microcrystalline silicon n layers. These were deposited using plasma-enhanced chemical vapor deposition. The non-semiconductor materials studied were tin oxide, for use as a transparent-conducting-oxide (TCO), and zinc oxide, for use as a back reflector and as a buffer layer between the TCO and the semiconductor layers. Tin oxide was deposited using atmospheric-pressure chemical vapor deposition. Zinc oxide was deposited using magnetron sputtering. The research indicated that the major challenge in the fabrication of a-Si multijunction PV modules is the contact between the two p-i-n cells. A structure that has low optical absorption but that also facilitates the recombination of electrons from the first p-i-n structure with holes from the second p-i-n structure is required. Non-semiconductor layers and a-Si semiconductor layers were tested without achieving the desired result.

  3. Oriented niobate ferroelectric thin films for electrical and optical devices

    DOE Patents [OSTI]

    Wessels, Bruce W.; Nystrom, Michael J.

    2001-01-01

    Sr.sub.x Ba.sub.1-x Nb.sub.2 O.sub.6, where x is greater than 0.25 and less than 0.75, and KNbO.sub.3 ferroelectric thin films metalorganic chemical vapor deposited on amorphous or cyrstalline substrate surfaces to provide a crystal axis of the film exhibiting a high dielectric susceptibility, electro-optic coefficient, and/or nonlinear optic coefficient oriented preferentially in a direction relative to a crystalline or amorphous substrate surface. Such films can be used in electronic, electro-optic, and frequency doubling components.

  4. Thin film composition with biological substance and method of making

    SciTech Connect (OSTI)

    Campbell, A.A.; Song, L.

    1999-09-28

    The invention provides a thin-film composition comprising an underlying substrate of a first material including a plurality of attachment sites; a plurality of functional groups chemically attached to the attachment sites of the underlying substrate; and a thin film of a second material deposited onto the attachment sites of the underlying substrate, and a biologically active substance deposited with the thin-film. Preferably the functional groups are attached to a self assembling monolayer attached to the underlying substrate. Preferred functional groups attached to the underlying substrate are chosen from the group consisting of carboxylates, sulfonates, phosphates, optionally substituted, linear or cyclo, alkyl, alkene, alkyne, aryl, alkylaryl, amine, hydroxyl, thiol, silyl, phosphoryl, cyano, metallocenyl, carbonyl, and polyphosphate. Preferred materials for the underlying substrate are selected from the group consisting of a metal, a metal alloy, a plastic, a polymer, a proteic film, a membrane, a glass or a ceramic. The second material is selected from the group consisting of inorganic crystalline structures, inorganic amorphous structures, organic crystalline structures, and organic amorphous structures. Preferred second materials are phosphates, especially calcium phosphates and most particularly calcium apatite. The biologically active molecule is a protein, peptide, DNA segment, RNA segment, nucleotide, polynucleotide, nucleoside, antibiotic, antimicrobial, radioisotope, chelated radioisotope, chelated metal, metal salt, anti-inflammatory, steroid, nonsteroid anti-inflammatory, analgesic, antihistamine, receptor binding agent, or chemotherapeutic agent, or other biologically active material. Preferably the biologically active molecule is an osteogenic factor consisting of the compositions listed above.

  5. Schottky barrier amorphous silicon solar cell with thin doped region adjacent metal Schottky barrier

    DOE Patents [OSTI]

    Carlson, David E.; Wronski, Christopher R.

    1979-01-01

    A Schottky barrier amorphous silicon solar cell incorporating a thin highly doped p-type region of hydrogenated amorphous silicon disposed between a Schottky barrier high work function metal and the intrinsic region of hydrogenated amorphous silicon wherein said high work function metal and said thin highly doped p-type region forms a surface barrier junction with the intrinsic amorphous silicon layer. The thickness and concentration of p-type dopants in said p-type region are selected so that said p-type region is fully ionized by the Schottky barrier high work function metal. The thin highly doped p-type region has been found to increase the open circuit voltage and current of the photovoltaic device.

  6. RF sputtering for controlling dihydride and monohydride bond densities in amorphous silicon hydride

    DOE Patents [OSTI]

    Jeffery, F.R.; Shanks, H.R.

    1980-08-26

    A process is described for controlling the dihydride and monohydride bond densities in hydrogenated amorphous silicone produced by reactive rf sputtering of an amorphous silicon target. There is provided a chamber with an amorphous silicon target and a substrate therein with the substrate and the target positioned such that when rf power is applied to the target the substrate is in contact with the sputtering plasma produced thereby. Hydrogen and argon are fed to the chamber and the pressure is reduced in the chamber to a value sufficient to maintain a sputtering plasma therein, and then rf power is applied to the silicon target to provide a power density in the range of from about 7 watts per square inch to about 22 watts per square inch to sputter an amorphous solicone hydride onto the substrate, the dihydride bond density decreasing with an increase in the rf power density. Substantially pure monohydride films may be produced.

  7. Sputtered Thin Film Photovoltaics - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Solar Photovoltaic Solar Photovoltaic Find More Like This Return to Search Sputtered Thin Film Photovoltaics Naval Research Laboratory Contact NRL About This Technology ...

  8. Superhydrophobic Thin Film Coatings - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Solar Thermal Solar Thermal Solar Photovoltaic Solar Photovoltaic Industrial Technologies ... Find More Like This Return to Search Superhydrophobic Thin Film Coatings Oak Ridge ...

  9. Amorphous silicon solar cells techniques for reactive conditions

    SciTech Connect (OSTI)

    Shimizu, Satoshi; Okawa, Kojiro; Kamiya, Toshio; Fortmann, C.M.; Shimizu, Isamu

    1999-07-01

    The preparation of amorphous silicon films and solar cells using SiH{sub 2}Cl{sub 2} source gas and electron cyclotron resonance assisted chemical vapor deposition (ECR-CVD) was investigated. By using buffer layers to protect previously deposited layers improved a-Si:H(Cl) solar cells were prepared and studied. The high quality a-Si:H(Cl) films used in this study exhibited low defect densities ({approximately}10{sup 15} cm{sup {minus}3}) and high stability under illumination even when the deposition rate was increased to {approximately} 15A/s. The solar cells were deposited in the n-i-p sequence. These solar cells achieved V{sub oc} values of {approximately}0.89V and {approximately}3.9% efficiency on Ga doped ZnO (GZO) coated specular substrate. The a-Si:H(Cl) electron and hole {mu}{tau} products were {approximately}10{sup {minus}8} cm{sup 2}/V.

  10. Hot wire deposited hydrogenated amorphous silicon solar cells

    SciTech Connect (OSTI)

    Mahan, A.H.; Iwaniczko, E.; Nelson, B.P.; Reedy, R.C. Jr.; Crandall, R.S.

    1996-05-01

    This paper details the results of a study in which low H content, high deposition rate hot wire (HW) deposited amorphous silicon (a-Si:H) has been incorporated into a substrate solar cell. The authors find that the treatment of the top surface of the HW i layer while it is being cooled from its high deposition temperature is crucial to device performance. They present data concerning these surface treatments, and correlate these treatments with Schottky device performance. The authors also present first generation HW n-i-p solar cell efficiency data, where a glow discharge (GD) {mu}c-Si(p) layer was added to complete the partial devices. No light trapping layer was used to increase the device Jsc. Their preliminary investigations have yielded efficiencies of up to 6.8% for a cell with a 4000 {Angstrom} thick HW i-layer, which degrade less than 10% after a 900 hour light soak. The authors suggest avenues for further improvement of their devices.

  11. Research on stable, high-efficiency amorphous silicon multijunction modules

    SciTech Connect (OSTI)

    Guha, S. )

    1991-12-01

    This report describes research to improve the understanding of amorphous silicon alloys and other relevant non-semiconductor materials for use in high-efficiency, large-area multijunction modules. The research produced an average subcell initial efficiency of 8.8% over a 1-ft{sup 2} area using same-band-gap, dual-junction cells deposited over a ZnO/AlSi back reflector. An initial efficiency of 9.6% was achieved using a ZnO/Ag back reflector over smaller substrates. A sputtering machine will be built to deposit a ZnO/Ag back reflector over a 1-ft{sup 2} area so that a higher efficiency can also be obtained on larger substrates. Calculations have been performed to optimize the grid pattern, bus bars, and cell interconnects on modules. With our present state of technology, we expect a difference of about 6% between the aperture-area and active-area efficiencies of modules. Preliminary experiments show a difference of about 8%. We can now predict the performance of single-junction cells after long-term light exposure at 50{degree}C by exposing cells to short-term intense light at different temperatures. We find that single-junction cells deposited on a ZnO/Ag back reflector show the highest stabilized efficiency when the thickness of the intrinsic layers is about 2000 {angstrom}. 8 refs.

  12. Amorphous silicon cell array powered solar tracking apparatus

    DOE Patents [OSTI]

    Hanak, Joseph J.

    1985-01-01

    An array of an even number of amorphous silicon solar cells are serially connected between first and second terminals of opposite polarity. The terminals are connected to one input terminal of a DC motor whose other input terminal is connected to the mid-cell of the serial array. Vane elements are adjacent the end cells to selectively shadow one or the other of the end cells when the array is oriented from a desired attitude relative to the sun. The shadowing of one cell of a group of cells on one side of the mid-cell reduces the power of that group substantially so that full power from the group of cells on the other side of the mid-cell drives the motor to reorient the array to the desired attitude. The cell groups each have a full power output at the power rating of the motor. When the array is at the desired attitude the power output of the two groups of cells balances due to their opposite polarity so that the motor remains unpowered.

  13. Hot wire deposited hydrogenated amorphous silicon solar cells

    SciTech Connect (OSTI)

    Mahan, A.H.; Nelson, B.P.; Iwaniczko, E.; Wang, Q.; Molenbroek, E.C.; Asher, S.E.; Reedy, R.C. Jr.; Crandall, R.S.

    1996-01-01

    This paper details preliminary results obtained in incorporating low H content, high substrate temperature hot wire (HW) deposited amorphous silicon material into a substrate solar cell structure. By necessity, since the learning curve for this complete structure involves metal/{ital n}-{ital i}/Schottky barrier structure optimization, a large part of the results are focused on this (partial) structure. We have found that the treatment of the top surface of the HW {ital i} layer during cooling is crucial to device performance. Without any particular attention paid to the treatment of this surface while the sample is cooling from its high deposition temperature, a significant amount of H diffuses out of the sample during the cooling process, particularly near the surface, resulting in devices with very poor photovoltaic properties. By designing a surface treatment to address this problem, we have been able to deposit HW Schottky structures with device characteristics as good as the best glow discharge devices produced in our laboratory. We present data concerning these surface treatments, and how they influence the H content at the {ital i}/Pd interface. {copyright} {ital 1996 American Institute of Physics.}

  14. Hot wire deposited hydrogenated amorphous silicon solar cells

    SciTech Connect (OSTI)

    Mahan, A.H.; Iwaniczko, E.; Nelson, B.P.; Reedy, R.C., Jr.; Unold, T.; Crandall, R.S.; Guha, S.; Yang, J. |

    1997-02-01

    This paper details the results of a study in which low H content, high deposition rate hot wire (HW) deposited amorphous silicon (a-Si:H) has been incorporated into a substrate solar cell. We find that the treatment of the top surface of the HW i-layer while it is cooled from its high deposition temperature is crucial to device performance. We present data concerning these surface treatments, and correlate these treatments with Schottky device performance. We also present first generation HW n-i-p solar cell data, where a glow discharge (GD) {mu}c-Si(p) layer completes the partial devices. No light trapping layer is used to increase the device Jsc. Our preliminary results yield efficiencies of up to 6.8{percent} for a cell with a 4000 {Angstrom} thick HW i-layer, which degrade less than 10{percent} after a 900h AM1 light soak. We suggest areas for further improvement of our devices. {copyright} {ital 1997 American Institute of Physics.}

  15. Hot wire deposited hydrogenated amorphous silicon solar cells

    SciTech Connect (OSTI)

    Mahan, A.H.; Iwaniczko, E.; Nelson, B.P.; Reedy, R.C. Jr.; Crandall, R.S.; Guha, S.; Yang, J.

    1996-09-01

    This paper details the results of a study in which low H content, high deposition rate hot wire (HW) deposited amorphous silicon (a-Si:H) has been incorporated into a substrate solar cell. The authors find that the treatment of the top surface of the HW i layer while it is being cooled from its high deposition temperature is crucial to device performance. They present data concerning these surface treatments, and they correlate these treatments with Schottky device performance. They also present first generation HW n-i-p solar cell efficiency data, where a glow discharge (GD) {mu}c-Si(p) layer was added to complete the partial devices. No light trapping layer was used to increase the device Jsc. The preliminary investigations have yielded efficiencies of up to 6.8% for a cell with a 4,000 {angstrom} thick HW i-layer, which degrade less than 10% after a 900 hour light soak. They suggest avenues for further improvement of the devices.

  16. Hydrogenated amorphous silicon barriers for niobium-niobium Josephson junctions

    SciTech Connect (OSTI)

    Kroger, H.; Aucoin, R.; Currier, L.W.; Jillie, D.W.; Potter, C.N.; Shaw, D.W.; Smith, L.N.; Thaxter, J.B.; Willis, P.H.

    1985-03-01

    The authors report on further studies of the effects of hydrogenation of sputtered amorphous silicon barriers upon the current-voltage (I-V) characteristics of Nb-Nb Josephson tunnel junctions. For composite trilayer barriers (a-Si/a-Si:H/a-Si) which are deposited using 8 mT of Ar, we find that there is an abrupt improvement in device characteristics when the central hydrogenated layer is deposited using a hydrogen partial pressure which exceeds about 0.5 mT. They attribute this to the reduction in the density of localized states in the a-Si:H layer. We have observed excellent I-V characteristics with trilayer barrier devices whose central hydrogenated layer is only about 1/7 of the thickness of the entire barrier. This observation suggests that localized states near the geometric center of the barrier are the most significant in degrading device characteristics. Annealing experiments and published data on the diffusion of deuterium in a-Si suggest that the composite barriers will be extremely stable during processing and storage. Zero bias anomalies in device I-V characteristics and spin density in the a-Si and a-Si:H layers have been measured.

  17. A NOVEL LOW THERMAL BUDGET THIN-FILM POLYSILICON FABRICATION PROCESS FOR LARGE-AREA, HIGH-THROUGHPUT SOLAR CELL PRODUCTION

    SciTech Connect (OSTI)

    Yue Kuo

    2010-08-15

    A novel thin-film poly-Si fabrication process has been demonstrated. This low thermal budget process transforms the single- and multi-layer amorphous silicon thin films into a poly-Si structure in one simple step over a pulsed rapid thermal annealing process with the enhancement of an ultrathin Ni layer. The complete poly-Si solar cell was fabricated in a short period of time without deteriorating the underneath glass substrate. The unique vertical crystallization process including the mechanism is discussed. Influences of the dopant type and process parameters on crystal structure will be revealed. The poly-Si film structure has been proved using TEM, XRD, Raman, and XPS methods. The poly-Si solar cell structure and the performance have been examined. In principle, the new process is potentially applicable to produce large-area thin-film poly-Si solar cells at a high throughput and low cost. A critical issue in this process is to prevent the excessive dopant diffusion during crystallization. Process parameters and the cell structure have to be optimized to achieve the production goal.

  18. Method of preparing high-temperature-stable thin-film resistors

    DOE Patents [OSTI]

    Raymond, L.S.

    1980-11-12

    A chemical vapor deposition method for manufacturing tungsten-silicide thin-film resistors of predetermined bulk resistivity and temperature coefficient of resistance (TCR) is disclosed. Gaseous compounds of tungsten and silicon are decomposed on a hot substrate to deposit a thin-film of tungsten-silicide. The TCR of the film is determined by the crystallinity of the grain structure, which is controlled by the temperature of deposition and the tungsten to silicon ratio. The bulk resistivity is determined by the tungsten to silicon ratio. Manipulation of the fabrication parameters allows for sensitive control of the properties of the resistor.

  19. Method of preparing high-temperature-stable thin-film resistors

    DOE Patents [OSTI]

    Raymond, Leonard S.

    1983-01-01

    A chemical vapor deposition method for manufacturing tungsten-silicide thin-film resistors of predetermined bulk resistivity and temperature coefficient of resistance (TCR). Gaseous compounds of tungsten and silicon are decomposed on a hot substrate to deposit a thin-film of tungsten-silicide. The TCR of the film is determined by the crystallinity of the grain structure, which is controlled by the temperature of deposition and the tungsten to silicon ratio. The bulk resistivity is determined by the tungsten to silicon ratio. Manipulation of the fabrication parameters allows for sensitive control of the properties of the resistor.

  20. Thin film solar energy collector

    DOE Patents [OSTI]

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

    1983-11-22

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

  1. Thin film buried anode battery

    DOE Patents [OSTI]

    Lee, Se-Hee; Tracy, C. Edwin; Liu, Ping

    2009-12-15

    A reverse configuration, lithium thin film battery (300) having a buried lithium anode layer (305) and process for making the same. The present invention is formed from a precursor composite structure (200) made by depositing electrolyte layer (204) onto substrate (201), followed by sequential depositions of cathode layer (203) and current collector (202) on the electrolyte layer. The precursor is subjected to an activation step, wherein a buried lithium anode layer (305) is formed via electroplating a lithium anode layer at the interface of substrate (201) and electrolyte film (204). The electroplating is accomplished by applying a current between anode current collector (201) and cathode current collector (202).

  2. Atmospheric Pressure Plasma CVD of Amorphous Hydrogenated Silicon Carbonitride (a-SiCN:H) Films Using Triethylsilane and Nitrogen

    SciTech Connect (OSTI)

    Srinivasan Guruvenket; Steven Andrie; Mark Simon; Kyle W. Johnson; Robert A. Sailer

    2011-10-04

    Amorphous hydrogenated silicon carbonitride (a-SiCN:H) thin films are synthesized by atmospheric pressure plasma enhanced chemical vapor (AP-PECVD) deposition using the Surfx Atomflow{trademark} 250D APPJ source with triethylsilane (HSiEt{sub 3}, TES) and nitrogen as the precursor and the reactive gases, respectively. The effect of the substrate temperature (T{sub s}) on the growth characteristics and the properties of a-SiCN:H films was evaluated. The properties of the films were investigated via scanning electron microscopy (SEM), atomic force microscopy (AFM) for surface morphological analyses, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) for chemical and compositional analyses; spectroscopic ellipsometry for optical properties and thickness determination and nanoindentation to determine the mechanical properties of the a-SiCN:H films. Films deposited at low T{sub s} depict organic like features, while the films deposited at high T{sub s} depict ceramic like features. FTIR and XPS studies reveal that an increases in T{sub s} helps in the elimination of organic moieties and incorporation of nitrogen in the film. Films deposited at T{sub s} of 425 C have an index of refraction (n) of 1.84 and hardness (H) of 14.8 GPa. A decrease in the deposition rate between T{sub s} of 25 and 250 C and increase in deposition rate between T{sub s} of 250 and 425 C indicate that the growth of a-SiCN:H films at lower T{sub s} are surface reaction controlled, while at high temperatures film growth is mass-transport controlled. Based on the experimental results, a potential route for film growth is proposed.

  3. Substrate-dependent thermal conductivity of aluminum nitride thin-films processed at low temperature

    SciTech Connect (OSTI)

    Belkerk, B. E.; Bensalem, S.; Soussou, A.; Carette, M.; Djouadi, M. A.; Scudeller, Y.; Al Brithen, H.

    2014-12-01

    In this paper, we report on investigation concerning the substrate-dependent thermal conductivity (k) of Aluminum Nitride (AlN) thin-films processed at low temperature by reactive magnetron sputtering. The thermal conductivity of AlN films grown at low temperature (<200 °C) on single-crystal silicon (Si) and amorphous silicon nitride (SiN) with thicknesses ranging from 100 nm to 4000 nm was measured with the transient hot-strip technique. The k values for AlN films on SiN were found significantly lower than those on Silicon consistently with their microstructures revealed by X-ray diffraction, high resolution scanning electron microscopy, and transmission electron microscopy. The change in k was due to the thermal boundary resistance found to be equal to 10 × 10{sup −9} Km{sup 2}W{sup −1} on SiN against 3.5 × 10{sup −9} Km{sup 2}W{sup −1} on Si. However, the intrinsic thermal conductivity was determined with a value as high as 200 Wm{sup −1}K{sup −1} whatever the substrate.

  4. Amorphous silicon Schottky barrier solar cells incorporating a thin insulating layer and a thin doped layer

    DOE Patents [OSTI]

    Carlson, David E.

    1980-01-01

    Amorphous silicon Schottky barrier solar cells which incorporate a thin insulating layer and a thin doped layer adjacent to the junction forming metal layer exhibit increased open circuit voltages compared to standard rectifying junction metal devices, i.e., Schottky barrier devices, and rectifying junction metal insulating silicon devices, i.e., MIS devices.

  5. New results on the microstructure of amorphous silicon as observed by internal friction

    SciTech Connect (OSTI)

    Crandall, R.S.; Mahan, A.H.; Iwaniczko, E.; Jones, K.M.; Liu, X.; White, B.E. Jr.; Pohl, R.O.

    1997-07-01

    The authors have measured the low temperature internal friction (Q{sup {minus}1}) of amorphous silicon (a-Si) films. Electron-beam evaporation leads to the well-known temperature-independent Q{sub 0}{sup {minus}1} plateau common to all amorphous solids. For hydrogenated amorphous silicon (a-Si:H) with about 1 at.% H produced by hot wire chemical vapor deposition, however, the value of Q{sub 0}{sup {minus}1} is over two hundred times smaller than for e-beam a-Si. This is the first observation of an amorphous solid without any significant low energy excitations. This finding offers the opportunity to study amorphous solids containing controlled densities of tunneling defects, and thus to explore their nature.

  6. Thin-Film Reliability Trends Toward Improved Stability: Preprint

    SciTech Connect (OSTI)

    Jordan, D. C.; Kurtz, S. R.

    2011-07-01

    Long-term, stable performance of photovoltaic (PV) modules will be increasingly important to their successful penetration of the power grid. This paper summarizes more than 150 thin-film and more than 1700 silicon PV degradation rates (Rd) quoted in publications for locations worldwide. Partitioning the literature results by technology and date of installation statistical analysis shows an improvement in degradation rate especially for thin-film technologies in the last decade. A CIGS array deployed at NREL for more than 5 years that appears to be stable supports the literature trends. Indoor and outdoor data indicate undetectable change in performance (0.2+/-0.2 %/yr). One module shows signs of slight degradation from what appears to be an initial manufacturing defect, however it has not affected the overall system performance.

  7. Zinc Oxide Thin Films Fabricated with Direct Current Magnetron Sputtering Deposition Technique

    SciTech Connect (OSTI)

    Hoon, Jian-Wei; Chan, Kah-Yoong; Krishnasamy, Jegenathan; Tou, Teck-Yong

    2011-03-30

    Zinc oxide (ZnO) is a very promising material for emerging large area electronic applications including thin-film sensors, transistors and solar cells. We fabricated ZnO thin films by employing direct current (DC) magnetron sputtering deposition technique. ZnO films with different thicknesses ranging from 100 nm to 1020 nm were deposited on silicon (Si) substrate. The deposition pressure was varied from 12 mTorr to 25 mTorr. The influences of the film thickness and the deposition pressure on structural properties of the ZnO films were investigated using Mahr surface profilometer and atomic force microscopy (AFM). The experimental results reveal that the film thickness and the deposition pressure play significant role in the structural formation of the deposited ZnO thin films. ZnO films deposited on Si substrates are promising for variety of thin-film sensor applications.

  8. Thin films of mixed metal compounds

    SciTech Connect (OSTI)

    Mickelsen, Reid A.; Chen, Wen S.

    1985-01-01

    A compositionally uniform thin film of a mixed metal compound is formed by simultaneously evaporating a first metal compound and a second metal compound from independent sources. The mean free path between the vapor particles is reduced by a gas and the mixed vapors are deposited uniformly. The invention finds particular utility in forming thin film heterojunction solar cells.

  9. Zinc oxide thin film acoustic sensor

    SciTech Connect (OSTI)

    Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah; Mansour, Hazim Louis

    2013-12-16

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

  10. Fatigue failure in thin-film polysilicon is due to subcriticalcracking within the oxide layer

    SciTech Connect (OSTI)

    Alsem, D.H.; Muhlstein, C.L.; Stach, E.A.; Ritchie, R.O.

    2005-01-11

    structure (i.e. a resonator) or those which arise from the service environment. While the reliability of MEMS has received extensive attention, the physical mechanisms responsible for these failure modes have yet to be conclusively determined. This is particularly true for fatigue, where the mechanisms have been subject to intense debate. Recently we have proposed that the fatigue of micron-scale polysilicon is associated with stress-induced surface oxide thickening and moisture-assisted subcritical cracking in the amorphous SiO{sub 2} oxide layer (''reaction-layer'' fatigue). The mechanism of oxide thickening is as yet unknown, but is likely related to some form of stress-assisted diffusion. Allameh et al. suggest a complementary mechanism involving stress-assisted oxide thickening, caused by dissolution of the surface oxide which forms deep grooves that are sites for crack initiation. Kahn et al. have criticized these mechanisms and proposed that, instead, fatigue is caused by subcritical cracking due to contacting surface asperities in the compressive part of the cycle. To the authors' knowledge, there is no direct experimental observation of such asperity contact. Also, their model cannot explain why micron-scale silicon, and not bulk silicon, is susceptible to fatigue. Moreover, Kahn et al. do not acknowledge the role of stress-induced oxide thickening, which has been observed directly using TEM and indirectly using atomic-force microscope measurements by several investigators, and have questioned whether the materials utilized by Muhlstein et al. and Allameh et al. were representative due to the relatively thick oxide scales. Accordingly, the goal of the present research is to seek a definitive understanding of the physical mechanisms responsible for fatigue in polysilicon structural thin-films. Our approach is to combine on-chip testing methods with electron microscopy by fatiguing thin-film samples and observing them, in an unthinned condition, using high

  11. Multilayer Thin-Film Thermoelectric Materials for Vehicle Applications...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Multilayer Thin-Film Thermoelectric Materials for Vehicle Applications Multilayer Thin-Film Thermoelectric Materials for Vehicle Applications 2004 Diesel Engine Emissions Reduction ...

  12. Solvothermal Thin Film Deposition of Electron Blocking Layers...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Solvothermal Thin Film Deposition of Electron Blocking Layers Home > Research > ANSER Research Highlights > Solvothermal Thin Film Deposition of Electron Blocking Layers...

  13. Partial Shade Stress Test for Thin-Film Photovoltaic Modules...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Partial Shade Stress Test for Thin-Film Photovoltaic Modules Preprint Timothy J. ... Partial shade stress test for thin-film photovoltaic modules Timothy J Silverman , ...

  14. Partial Shading in Monolithic Thin Film PV Modules: Analysis...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Partial Shading in Monolithic Thin Film PV Modules: Analysis and Design Partial Shading in Monolithic Thin Film PV Modules: Analysis and Design Presented at the PV Module ...

  15. High Temperature Thin Film Polymer Dielectric Based Capacitors...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Thin Film Polymer Dielectric Based Capacitors for HEV Power Electronic Systems High Temperature Thin Film Polymer Dielectric Based Capacitors for HEV Power Electronic Systems 2009 ...

  16. Nucleation of fcc Ta when heating thin films

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Janish, Matthew T.; Mook, William M.; Carter, C. Barry

    2014-10-25

    Thin tantalum films have been studied during in-situ heating in a transmission electron microscope. Diffraction patterns from the as-deposited films were typical of amorphous materials. Crystalline grains were observed to form when the specimen was annealed in-situ at 450°C. Particular attention was addressed to the formation and growth of grains with the face-centered cubic (fcc) crystal structure. As a result, these observations are discussed in relation to prior work on the formation of fcc Ta by deformation and during thin film deposition.

  17. Thin film solar cell including a spatially modulated intrinsic layer

    SciTech Connect (OSTI)

    Guha, Subhendu; Yang, Chi-Chung; Ovshinsky, Stanford R.

    1989-03-28

    One or more thin film solar cells in which the intrinsic layer of substantially amorphous semiconductor alloy material thereof includes at least a first band gap portion and a narrower band gap portion. The band gap of the intrinsic layer is spatially graded through a portion of the bulk thickness, said graded portion including a region removed from the intrinsic layer-dopant layer interfaces. The band gap of the intrinsic layer is always less than the band gap of the doped layers. The gradation of the intrinsic layer is effected such that the open circuit voltage and/or the fill factor of the one or plural solar cell structure is enhanced.

  18. Passivation of c-Si surfaces by sub-nm amorphous silicon capped with silicon nitride

    SciTech Connect (OSTI)

    Wan, Yimao Yan, Di; Bullock, James; Zhang, Xinyu; Cuevas, Andres

    2015-12-07

    A sub-nm hydrogenated amorphous silicon (a-Si:H) film capped with silicon nitride (SiN{sub x}) is shown to provide a high level passivation to crystalline silicon (c-Si) surfaces. When passivated by a 0.8 nm a-Si:H/75 nm SiN{sub x} stack, recombination current density J{sub 0} values of 9, 11, 47, and 87 fA/cm{sup 2} are obtained on 10 Ω·cm n-type, 0.8 Ω·cm p-type, 160 Ω/sq phosphorus-diffused, and 120 Ω/sq boron-diffused silicon surfaces, respectively. The J{sub 0} on n-type 10 Ω·cm wafers is further reduced to 2.5 ± 0.5 fA/cm{sup 2} when the a-Si:H film thickness exceeds 2.5 nm. The passivation by the sub-nm a-Si:H/SiN{sub x} stack is thermally stable at 400 °C in N{sub 2} for 60 min on all four c-Si surfaces. Capacitance–voltage measurements reveal a reduction in interface defect density and film charge density with an increase in a-Si:H thickness. The nearly transparent sub-nm a-Si:H/SiN{sub x} stack is thus demonstrated to be a promising surface passivation and antireflection coating suitable for all types of surfaces encountered in high efficiency c-Si solar cells.

  19. Growth of solid and hollow gold particles through the thermal annealing of nanoscale patterned thin films

    SciTech Connect (OSTI)

    Lin, Junhao; He, Weidong; Vilayur Ganapathy, Subramanian; Peppernick, Samuel J.; Wang, Bin; Palepu, Sandeep; Remec, Miroslav; Hess, Wayne P.; Hmelo, Anthony B.; Pantelides, Sokrates T.; Dickerson, James

    2013-11-27

    Through thermally annealing well-arrayed, circular, nanoscale thin films of gold, deposited onto [111] silicon/silicon dioxide substrates, both solid and hollow gold particles of different morphologies with controllable sizes were obtained. The thin film could form individual particle or clusters of particles by tuning the diameter of it. Hollow gold particles were featured by their large size whose diameter was larger than 500 nm and confirmed by a cross-section view. Hollow gold particles show greater plasmonic field enhancement under photoemission electron microscopy. Potential growth mechanisms for these structures are explored

  20. Internal Friction of Amorphous and Nanocrystalline Silicon Containing Hydrogen: Preprint

    SciTech Connect (OSTI)

    Merithew, R. D.; Liu, X.; Wang, Q.; Crandall, R. S.; Pohl, R. O.

    2001-10-01

    Presented at the 2001 NCPV Program Review Meeting: Using methods of elastic properties to study disorder of thin silicon films.

  1. The origins of growth stresses in amorphous semiconductor thin...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: The origins of growth stresses in amorphous semiconductor thin films. Citation Details In-Document ... Publication Date: 2003-03-01 OSTI Identifier: 917484 Report ...

  2. Geometric shape control of thin film ferroelectrics and resulting structures

    DOE Patents [OSTI]

    McKee, Rodney A.; Walker, Frederick J.

    2000-01-01

    A monolithic crystalline structure and a method of making involves a semiconductor substrate, such as silicon, and a ferroelectric film, such as BaTiO.sub.3, overlying the surface of the substrate wherein the atomic layers of the ferroelectric film directly overlie the surface of the substrate. By controlling the geometry of the ferroelectric thin film, either during build-up of the thin film or through appropriate treatment of the thin film adjacent the boundary thereof, the in-plane tensile strain within the ferroelectric film is relieved to the extent necessary to permit the ferroelectric film to be poled out-of-plane, thereby effecting in-plane switching of the polarization of the underlying substrate material. The method of the invention includes the steps involved in effecting a discontinuity of the mechanical restraint at the boundary of the ferroelectric film atop the semiconductor substrate by, for example, either removing material from a ferroelectric film which has already been built upon the substrate, building up a ferroelectric film upon the substrate in a mesa-shaped geometry or inducing the discontinuity at the boundary by ion beam deposition techniques.

  3. Stable, high-efficiency amorphous silicon solar cells with low hydrogen content

    SciTech Connect (OSTI)

    Fortmann, C.M.; Hegedus, S.S. )

    1992-12-01

    Results and conclusions obtained during a research program of the investigation of amorphous silicon and amorphous silicon based alloy materials and solar cells fabricated by photo-chemical vapor and glow discharge depositions are reported. Investigation of the effects of the hydrogen content in a-si:H i-layers in amorphous silicon solar cells show that cells with lowered hydrogen content i-layers are more stable. A classical thermodynamic formulation of the Staebler-Wronski effect has been developed for standard solar cell operating temperatures and illuminations. Methods have been developed to extract a lumped equivalent circuit from the current voltage characteristic of a single junction solar cell in order to predict its behavior in a multijunction device.

  4. Electron-beam-evaporated thin films of hafnium dioxide for fabricating electronic devices

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Xiao, Zhigang; Kisslinger, Kim

    2015-06-17

    Thin films of hafnium dioxide (HfO2) are widely used as the gate oxide in fabricating integrated circuits because of their high dielectric constants. In this paper, the authors report the growth of thin films of HfO2 using e-beam evaporation, and the fabrication of complementary metal-oxide semiconductor (CMOS) integrated circuits using this HfO2 thin film as the gate oxide. The authors analyzed the thin films using high-resolution transmission electron microscopy and electron diffraction, thereby demonstrating that the e-beam-evaporation-grown HfO2 film has a polycrystalline structure and forms an excellent interface with silicon. Accordingly, we fabricated 31-stage CMOS ring oscillator to test themore » quality of the HfO2 thin film as the gate oxide, and obtained excellent rail-to-rail oscillation waveforms from it, denoting that the HfO2 thin film functioned very well as the gate oxide.« less

  5. Electron-beam-evaporated thin films of hafnium dioxide for fabricating electronic devices

    SciTech Connect (OSTI)

    Xiao, Zhigang; Kisslinger, Kim

    2015-06-17

    Thin films of hafnium dioxide (HfO2) are widely used as the gate oxide in fabricating integrated circuits because of their high dielectric constants. In this paper, the authors report the growth of thin films of HfO2 using e-beam evaporation, and the fabrication of complementary metal-oxide semiconductor (CMOS) integrated circuits using this HfO2 thin film as the gate oxide. The authors analyzed the thin films using high-resolution transmission electron microscopy and electron diffraction, thereby demonstrating that the e-beam-evaporation-grown HfO2 film has a polycrystalline structure and forms an excellent interface with silicon. Accordingly, we fabricated 31-stage CMOS ring oscillator to test the quality of the HfO2 thin film as the gate oxide, and obtained excellent rail-to-rail oscillation waveforms from it, denoting that the HfO2 thin film functioned very well as the gate oxide.

  6. Structural characterization of thin film photonic crystals

    SciTech Connect (OSTI)

    Subramania, G.; Biswas, R.; Constant, K.; Sigalas, M. M.; Ho, K. M.

    2001-06-15

    We quantitatively analyze the structure of thin film inverse-opal photonic crystals composed of ordered arrays of air pores in a background of titania. Ordering of the sphere template and introduction of the titania background were performed simultaneously in the thin film photonic crystals. Nondestructive optical measurements of backfilling with high refractive index liquids, angle-resolved reflectivity, and optical spectroscopy were combined with band-structure calculations. The analysis reveals a thin film photonic crystal structure with a very high filling fraction (92{endash}94%) of air and a substantial compression along the c axis ({similar_to}22{endash}25%).

  7. Pulsed energy synthesis and doping of silicon carbide

    DOE Patents [OSTI]

    Truher, Joel B.; Kaschmitter, James L.; Thompson, Jesse B.; Sigmon, Thomas W.

    1995-01-01

    A method for producing beta silicon carbide thin films by co-depositing thin films of amorphous silicon and carbon onto a substrate, whereafter the films are irradiated by exposure to a pulsed energy source (e.g. excimer laser) to cause formation of the beta-SiC compound. Doped beta-SiC may be produced by introducing dopant gases during irradiation. Single layers up to a thickness of 0.5-1 micron have been produced, with thicker layers being produced by multiple processing steps. Since the electron transport properties of beta silicon carbide over a wide temperature range of 27.degree.-730.degree. C. is better than these properties of alpha silicon carbide, they have wide application, such as in high temperature semiconductors, including hetero-junction bipolar transistors and power devices, as well as in high bandgap solar arrays, ultra-hard coatings, light emitting diodes, sensors, etc.

  8. Pulsed energy synthesis and doping of silicon carbide

    DOE Patents [OSTI]

    Truher, J.B.; Kaschmitter, J.L.; Thompson, J.B.; Sigmon, T.W.

    1995-06-20

    A method for producing beta silicon carbide thin films by co-depositing thin films of amorphous silicon and carbon onto a substrate is disclosed, whereafter the films are irradiated by exposure to a pulsed energy source (e.g. excimer laser) to cause formation of the beta-SiC compound. Doped beta-SiC may be produced by introducing dopant gases during irradiation. Single layers up to a thickness of 0.5-1 micron have been produced, with thicker layers being produced by multiple processing steps. Since the electron transport properties of beta silicon carbide over a wide temperature range of 27--730 C is better than these properties of alpha silicon carbide, they have wide application, such as in high temperature semiconductors, including HETEROJUNCTION-junction bipolar transistors and power devices, as well as in high bandgap solar arrays, ultra-hard coatings, light emitting diodes, sensors, etc.

  9. Permanent laser conditioning of thin film optical materials

    DOE Patents [OSTI]

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

    1995-01-01

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

  10. Permanent laser conditioning of thin film optical materials

    DOE Patents [OSTI]

    Wolfe, C.R.; Kozlowski, M.R.; Campbell, J.H.; Staggs, M.; Rainer, F.

    1995-12-05

    The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold. 9 figs.