Showing papers on "Oxide published in 2005"
TL;DR: In this paper, the authors developed a new type of solar cell that is based on a photoelectrochemical process, where the light absorption is performed by a monolayer of dye (i.e., a Ruthenium complex) that is adsorbed chemically at the surface of a semiconductor.
Abstract: During the past five years, the authors have developed in their laboratory a new type of solar cell that is based on a photoelectrochemical process. The light absorption is performed by a monolayer of dye (i.e., a Ruthenium complex) that is adsorbed chemically at the surface of a semiconductor (i.e., titanium oxide (TiO{sub 2})). When excited by a photon, the dye has the ability to transfer an electron to the semiconductor. The electric field that is inside the material allows extraction of the electron, and the positive charge is transferred from the dye to a redox mediator that is present in solution. A respectable photovoltaic efficiency (i.e., 10%) is obtained by the use of mesoporous, nanostructured films of anatase particles. The authors show how the TiO{sub 2} electrode microstructure influences the photovoltaic response of the cell. More specifically, they focus on how processing parameters such as precursor chemistry, temperature for hydrothermal growth, binder addition, and sintering conditions influence the film porosity, pore-size distribution, light scattering, and electron percolation and consequently affect the solar-cell efficiency.
1,552 citations
Patent•
09 Nov 2005TL;DR: In this paper, a P-type and N-type region was defined for transparent oxide film-based semiconductor devices and circuits with use of transparent oxide films, where amorphous oxides with electron carrier concentration less than 10 18 /cm 3 were used for the N-Type region.
Abstract: Semiconductor devices and circuits with use of transparent oxide film are provided. The semiconductor device having a P-type region and an N-type region, wherein amorphous oxides with electron carrier concentration less than 10 18 /cm 3 is used for the N-type region.
1,073 citations
TL;DR: In this article, a correlation between the particle size and the lattice parameter has been established in nanocerium oxide particles (3-30nm) and the variation in lattice parameters is attributed to lattice strain induced by the introduction of Ce3+ due to the formation of oxygen vacancies.
Abstract: A correlation between the particle size and the lattice parameter has been established in nanocerium oxide particles (3–30nm). The variation in the lattice parameter is attributed to the lattice strain induced by the introduction of Ce3+ due to the formation of oxygen vacancies. Lattice strain was observed to decrease with an increase in the particle size. Ce3+ ions concentration increased from 17% to 44% with the reduction in the particle size.
966 citations
TL;DR: This work has developed a method for preparing highly uniform monodisperse nanocrystals of Cu(2)O, and confirmed the thin layer of CuO, which is blue-shifted, and appears to increase in energy as a function of decreasing particle size.
Abstract: It is well-known that inorganic nanocrystals are a benchmark model for nanotechnology, given that the tunability of optical properties and the stabilization of specific phases are uniquely possible at the nanoscale. Copper (I) oxide (Cu(2)O) is a metal oxide semiconductor with promising applications in solar energy conversion and catalysis. To understand the Cu/Cu(2)O/CuO system at the nanoscale, we have developed a method for preparing highly uniform monodisperse nanocrystals of Cu(2)O. The procedure also serves to demonstrate our development of a generalized method for the synthesis of transition metal oxide nanocrystals. Cu nanocrystals are initially formed and subsequently oxidized to form highly crystalline Cu(2)O. The volume change during phase transformation can induce crystal twinning. Absorption in the visible region of the spectrum gave evidence for the presence of a thin, epitaxial layer of CuO, which is blue-shifted, and appears to increase in energy as a function of decreasing particle size. XPS confirmed the thin layer of CuO, calculated to have a thickness of approximately 5 A. We note that the copper (I) oxide phase is surprisingly well-stabilized at this length scale.
845 citations
TL;DR: Osteoblasts grown on modified Ti surfaces exhibited a more differentiated phenotype characterized by increased alkaline phosphatase activity and osteocalcin and generated an osteogenic microenvironment through higher production of PGE2 and TGF-beta1 and 1alpha,25OH2D3 increased these effects in a manner that was synergistic with high surface energy.
Abstract: Titanium (Ti) is used for implantable devices because of its biocompatible oxide surface layer. TiO2 surfaces that have a complex microtopography increase bone-to-implant contact and removal torque forces in vivo and induce osteoblast differentiation in vitro. Studies examining osteoblast response to controlled surface chemistries indicate that hydrophilic surfaces are osteogenic, but TiO2 surfaces produced until now exhibit low surface energy because of adsorbed hydrocarbons and carbonates from the ambient atmosphere or roughness induced hydrophobicity. Novel hydroxylated/hydrated Ti surfaces were used to retain high surface energy of TiO2. Osteoblasts grown on this modified surface exhibited a more differentiated phenotype characterized by increased alkaline phosphatase activity and osteocalcin and generated an osteogenic microenvironment through higher production of PGE2 and TGF-beta1. Moreover, 1alpha,25OH2D3 increased these effects in a manner that was synergistic with high surface energy. This suggests that increased bone formation observed on modified Ti surfaces in vivo is due in part to stimulatory effects of high surface energy on osteoblasts.
844 citations
TL;DR: In this article, anatase Ti1−xNbxO2 films with x = 0.002-0.2 have been shown to have high resistivity and transport and optical properties comparable to those of typical TCOs, such as In2−xSnxO3 and ZnO.
Abstract: This Letter focuses on the discovery of a transparent conducting oxide (TCO), anatase Ti1−xNbxO2 films with x=0.002–0.2. The resistivity of films with x⩾0.03 is 2–3×10−4Ωcm at room temperature. The carrier density of Ti1−xNbxO2 can be controlled in a range of 1×1019to2×1021cm−3. The internal transmittance for films with x⩽0.03 (40nm thickness) is about 97% in the visible light region. The transport and optical parameters are comparable to those of typical TCOs, such as In2−xSnxO3 and ZnO.
737 citations
25 Apr 2005-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the authors compared the performance and cost-effectiveness of solid oxide fuel cells (SOFCs) with two approaches (metallic and ceramic) to the development of interconnect materials.
Abstract: One of the challenges in improving the performance and cost-effectiveness of solid oxide fuel cells (SOFCs) is the development of suitable interconnect materials. The interconnect material is in contact with both the anode and the cathode, and thus must be stable with both electrode materials and in oxidizing and reducing environments. The interconnect material must also maintain a low electrical resistance during cell operation to avoid decreased efficiency due to ohmic losses. The common feature of the two approaches (metallic and ceramic) to the development of interconnect materials is the presence of chromium. The most promising ceramic materials are chromites, while the most promising metallic materials are chromia-forming alloys. The focus of this paper is comparison of metallic alloys for use as interconnects in solid oxide fuel cells, in terms of properties including oxidation resistance, volatility, electrical resistance and thermal expansion.
692 citations
TL;DR: The controlled organization of molecules and molecular assemblies on silicon oxide will have a prominent place in "bottom-up" nanofabrication, which could revolutionize fields such as nanoelectronics and biotechnology in the near future.
Abstract: Although a molecular monolayer is only a few nanometers thick it can completely change the properties of a surface. Molecular monolayers can be readily prepared using the Langmuir-Blodgett methodology or by chemisorption on metal and oxide surfaces. This Review focuses on the use of chemisorbed self-assembled monolayers (SAMs) as a platform for the functionalization of silicon oxide surfaces. The controlled organization of molecules and molecular assemblies on silicon oxide will have a prominent place in bottom-up nanofabrication, which could revolutionize fields such as nanoelectronics and biotechnology in the near future. In recent years, self-assembled monolayers on silicon oxide have reached a high level of sophistication and have been combined with various lithographic patterning methods to develop new nanofabrication protocols and biological arrays. Nanoscale control over surface properties is of paramount importance to advance from 2D patterning to 3D fabrication.
666 citations
Patent•
21 Jul 2005TL;DR: In this article, a mixing layer is constituted that Ru is diffused in an LaNiO 3 -based film in order to raise adhesiveness of an Ru-based layer to the interface of the LaNiOs 3-based film, using lower electrodes wherein perovskite type conductivity oxide La NiO 3 and Ru which is noble metal are laminated, and moreover the orientation degree of Ru (002) is 90% or more.
Abstract: PROBLEM TO BE SOLVED: To enable mixed mounting with a highly efficient electrical body capacitative element and a highly efficient logic circuit, by forming a dielectrics capacitative element of perovskite structure at low temperature, as well as by suppressing characteristic fluctuation and characteristics degradation of an integrated circuit. SOLUTION: In Pb-based perovskite dielectrics capacitative element, a mixing layer is so constituted that Ru is diffused in an LaNiO 3 -based film in order to raise adhesiveness of an Ru-based layer to the interface of the LaNiO 3 -based film, using lower electrodes wherein perovskite type conductivity oxide LaNiO 3 and Ru which is noble metal are laminated, and moreover the orientation degree of Ru (002) is 90% or more, and LaNiO 3 has a preference orientation degree (100), so that the orientation and grain size of a PZT film are controlled. Thus, the PZT film excellent in flatness and orientation is obtained. COPYRIGHT: (C)2005,JPO&NCIPI
651 citations
TL;DR: In this paper, the structural and physical properties of nanoscaled metal oxide films (SnO2 and In2O3) aimed for solid state chemical sensors were analyzed and the methods suitable for control of these structural-and physical-chemical parameters have been discussed.
Abstract: In this review the structural and physical–chemical properties of nanoscaled metal oxide films (SnO2 and In2O3), aimed for solid state chemical sensors were analyzed. It has been shown that structural factor even for nanoscaled materials is complicated conception. One has to consider not only size, but also such a parameters as crystallite shape; nanoscopic structure; crystallographic orientation of nanocrystallites planes, forming gas sensing surface; film agglomeration; phase composition; surface architecture. The methods suitable for control of these structural and physical–chemical parameters have been discussed. Results, mainly obtained during study of both SnO2 and In2O3 thin films deposited by spray pyrolysis have been used for showing an opportunity of structural engineering of metal oxides for optimization of gas sensing characteristics.
601 citations
TL;DR: Two methodic concepts, symmetric and asymmetric Ostwald ripening, are elucidated by solution-route syntheses of oxide and sulfide semiconductors, which will allow the construction of complex architectures, including nonspherical configurations.
Abstract: Two methodic concepts, symmetric and asymmetric Ostwald ripening, are elucidated by solution-route syntheses of oxide and sulfide semiconductors. While the original shape of a crystallite aggregate forms the exterior appearance, the preorganization of the crystallites determines the ultimate interior space structure of the aggregate upon Ostwald ripening. Further investigations on the design of crystallite preorganization and control of the solution process will allow the construction of complex architectures, including nonspherical configurations.
TL;DR: In this paper, the authors report on blue-light emission at room temperature from Ar+-irradiated, metallic SrTiO3 (STO) and propose a model by which the doped conduction electrons and the in-gap state produce a radiative process that results in blue light emission.
Abstract: Oxide-based electronic devices are expected to have fascinating properties, unlike those made from conventional semiconductors. SrTiO3 (STO) is a key material for this new field of electronics1,2,3,4,5,6,7,8,9,10,11. Here we report on blue-light emission at room temperature from Ar+-irradiated, metallic STO. The irradiation introduces oxygen deficiencies to a depth of ∼20 nm from the crystal surface. These deficiencies generate conduction carriers and stabilize a hole level in a self-trapped state. We propose a model by which the doped conduction electrons and the in-gap state produce a radiative process that results in blue-light emission. The emitting region can be patterned into any size and shape with conventional microscopic fabrication techniques.
TL;DR: The most significant finding of the study is that the anion exchanger as a substrate containing dispersed HFO offered substantially higher arsenate removal capacity as compared to the cation exchanger, all other conditions remaining identical.
Abstract: The conditions leading to the Donnan membrane equilibrium arise from the inability of ions to diffuse out from one phase in a heterogeneous system. In a polymeric cation exchanger, negatively charged sulfonic acid groups are covalently attached to the polymer chains, and thus, they cannot permeate out of the polymer phase. Conversely, a polymeric anion exchanger contains a high concentration of non-diffusible positively charged quaternary ammonium functional groups. It is well-established that submicron or nanoscale hydrated iron(III) oxide (HFO) particles exhibit high sorption affinity toward both arsenates and arsenites. In this study, commercially available cation and anion exchangers were used as host materials for dispersing HFO nanoparticles within the polymer phase using a technique previously developed. The resulting polymeric/inorganic hybrid sorbent particles were subsequently used for arsenic removal in the laboratory. The most significant finding of the study is that the anion exchanger as a s...
TL;DR: The catalysis science of mixed metal oxides has undergone dramatic paradigm changes over the past 25 years as new characterization techniques became available (X-ray absorption spectroscopy (EXAFS/XANES/soft XANES), Raman, solidstate NMR, HR-TEM, UV-vis DRS and LEISS) to catalysis researchers as discussed by the authors.
TL;DR: It is demonstrated that cuprous oxide Cu(2)O nanospheres with hollow interiors can be fabricated from a reductive conversion of aggregated CuO nanocrystallites without using templates, and can be potentially useful for harvesting solar energy in the visible range.
Abstract: In this work, we demonstrate that cuprous oxide Cu2O nanospheres with hollow interiors can be fabricated from a reductive conversion of aggregated CuO nanocrystallites without using templates. A detailed process mechanism has been revealed: (i) formation of CuO nanocrystallites; (ii) spherical aggregation of primary CuO crystallites; (iii) reductive conversion of CuO to Cu2O; and (iv) crystal aging and hollowing of Cu2O nanospheres. In this template-free process, Ostwald ripening is operative in (iv) for controlling crystallite size in shell structures and thus for precisely tuning the optical band gap energy (Eg) of resultant semiconductor nanostructures. For the first time, a wealth of colorful Cu2O hollow nanospheres (outer diameters in 100−200 nm), with variable Eg in the range of 2.405−2.170 eV, has been fabricated via this novel chemical route. Considering their unique hollow structure and facile tuning in band gap energy, the prepared Cu2O hollow spheres can be potentially useful for harvesting so...
TL;DR: High-quality ultralong copper nanowires can be synthesized in large scale with a facile aqueous reduction route at low cost and can be used as starting solid precursor for fabrication of polycrystalline oxide nanotubes via direct oxidation in air.
Abstract: The present difficulties in synthesis of one-dimensional copper are short length, nonlinear morphology, polydispersivity, poor crystallinity, low yield, and process complexity. In this work, we demonstrate that high-quality ultralong copper nanowires (90-120 nm in diameter, 40-50 microm in length; aspect ratio >350-450) can be synthesized in large scale with a facile aqueous reduction route at low cost. The prepared copper nanowires can also be used as starting solid precursor for fabrication of polycrystalline oxide nanotubes via direct oxidation in air.
TL;DR: In this paper, the authors used X-ray diffraction to study the oxidation of aluminum powders at elevated temperatures and found that the oxide layer thickness exceeds the critical thickness of amorphous alumina of about 4 nm, when the oxide transforms into γ-Al2O3.
TL;DR: In this paper, the energy levels of the oxygen vacancy and oxygen interstitial defects in HfO2 were calculated using density functional methods that do not need an empirical band gap correction.
Abstract: This letter presents calculations of the energy levels of the oxygen vacancy and oxygen interstitial defects in HfO2 using density functional methods that do not need an empirical band gap correction The levels are aligned to those of the Si channel using the known band offsets The oxygen vacancy gives an energy level nearer the HfO2 conduction band and just above the Si gap, depending on its charge state It is identified as the main electron trap in HfO2 The oxygen interstitial gives levels just above the oxide valence band
TL;DR: In this paper, the authors focus on those studies that have resulted in changed views of the importance of various mechanisms of corrosion in water-cooled PWRs and present a review of these studies.
TL;DR: In this paper, an attempt is made to rationalise the various factors and the interconnections to the structure, the texture, and the effects of the nanometre scale, which all contribute to the properties of these materials.
Abstract: Nanostructured CeO2–ZrO2 mixed oxides have attracted great interest in the past 10 years, in particular as redox or oxygen storage promoters in the three-way catalysts. However, it has now became clear that both the chemistry of the simple oxides and the complex metal–CeO2-based oxide interactions can play a critical role in developing novel and highly active materials for a number of processes, ranging from catalysts for H2 production from fuels up to ceramic materials and solid state conductors for fuel cells. Despite the apparent simplicity of these systems, extreme variability of their chemical and textural properties has been observed. An attempt is made here to rationalise the various factors and the inter-connections to the structure, the texture, and the effects of the nanometre scale, which all contribute to the properties of these materials.
24 Aug 2005
TL;DR: In this article, the authors investigated the physical properties of surface metal oxides and their properties in terms of the number of active sites in a supported and bulk metal oxide catalysts through Methanol Chemisorption.
Abstract: Molecular Structures of Surface Metal Oxide Species: Nature of Catalytic Active Sites in Mixed Metal Oxides I.E. Wachs Nanostructured Supported Metal Oxides M.S. Wong Defect Chemistry and Transport in Metal Oxides A. Thursfield, A. Kruth, J.T.S Irvine, and I.S. Metcalfe Cation Valence States of Transitional Metal Oxides Analyzed by Electron Energy-Loss Spectroscopy Z..L. Wang Surface Processes and Composition of Metal Oxide Surfaces B. Pawelec The Electronic Structure of Metal Oxides P.M. Woodward, H. Mizoguchi, Y.-I. Kim, and M.W. Stoltzfus Optical and Magnetic Properties of Metal Oxides S. Ishihara Redox Properties of Metal Oxides B.M. Reddy The Surface Acidity and Basicity of Solid Oxides and Zeolites G. Busca Optical Basicity: A Scale of Acidity/Basicity of Solids and Its Application to Oxidation Catalysis E. Bordes-Richard and P. Courtine Investigation of the Nature and Number of Surface Active Sites of Supported and Bulk Metal Oxide Catalysts through Methanol Chemisorption L.E. Briand Combinatorial Approaches to Design Complex Metal Oxides F. Schuth and S.A. Schunk Propane Selective Oxidation to Propene and Oxygenates on Metal Oxides E.K. Novakova and J.C. Vedrine Methane Oxidation on Metal Oxides R.M. Navarro, M.A. Pena, and J.L.G. Fierro Oxidative Dehydrogenation (ODH) of Alkanes over Metal Oxide Catalysts G. Deo, M. Cherian, and T.V.M. Rao Metathesis of Olefins on Metal Oxides J.L.G. Fierro and J.C. Mol Applications of Metal Oxides for Volatile Organic Compound Combustion D.P. Dissanayake Hydrogenation of Carbon Oxides on Metal Oxides J.L.G. Fierro Photocatalysis: Photocatalysis on Titanium Oxide-Based Catalysts M. Anpo, S. Dohshi, M. Kitano, and Y. Hu Photocatalytic Activity forWater Decomposition of RuO2-Dispersed p-Block Metal Oxides with d10 Electronic Configuration Y. Inoue Selective Catalytic Reduction (SCR) Processes on Metal Oxides G. Centi and S. Perathoner Gas Sensors Based on Semiconducting Metal Oxides A. Gurlo, N. Barsan, and U. Weimar Fuel Electrodes for Solid Oxide Fuel Cells S.W. Tao and J.T.S. Irvine Index
TL;DR: In this paper, the authors focus on the case of gate dielectrics of interest for current Si microelectronics, i.e., Si oxides or oxynitrides of thickness ranging from some tens of nanometers down to about 1nm.
Abstract: In this paper we review the subject of oxide breakdown (BD), focusing our attention on the case of the gate dielectrics of interest for current Si microelectronics, i.e., Si oxides or oxynitrides of thickness ranging from some tens of nanometers down to about 1nm. The first part of the paper is devoted to a concise description of the subject concerning the kinetics of oxide degradation under high-voltage stress and the statistics of the time to BD. It is shown that, according to the present understanding, the BD event is due to a buildup in the oxide bulk of defects produced by the stress at high voltage. Defect concentration increases up to a critical value corresponding to the onset of one percolation path joining the gate and substrate across the oxide. This triggers the BD, which is therefore believed to be an intrinsic effect, not due to preexisting, extrinsic defects or processing errors. We next focus our attention on experimental studies concerning the kinetics of the final event of BD, during whi...
TL;DR: In this paper, the anodic formation of nanoporous TiO2 on titanium was investigated in Na2SO4 electrolytes containing low concentrations of NaF (0.1-1/1/5%).
TL;DR: In this article, the authors report on the high activity and stability of low-content gold-cerium oxide catalysts for the water-gas shift reaction (WGS) and show that the determining factor for the retention of active gold in ceria is the surface properties of the latter.
Abstract: We report here on the high activity and stability of low-content gold–cerium oxide catalysts for the water–gas shift reaction (WGS). These catalysts are reversible in cyclic reduction–oxidation treatment up to 400 8C, are non-pyrophoric, and are thus potential candidates for application to hydrogen generation for fuel cell power production. Low-content (0.2–0.9 at.%) gold–ceria samples were prepared by singlepot synthesis by the urea gelation/coprecipitation method; and by sodium cyanide leaching of high-content (2–8 at.%) gold–ceria materials prepared by various techniques. The low-content gold–ceria catalysts are free of metallic gold nanoparticles. Gold is present in oxidized form, as verified by a variety of analytical techniques. However, these materials display the same WGS activity as the high-content gold ones, and remain free of gold nanoparticles after use in a reaction gas stream composed of 11% CO–26% H2O–26% H2–7% CO2–balance He up to 300 8C. We show that the determining factor for the retention of active gold in ceria is the surface properties of the latter. Measurements of lattice constant expansion indicate gold ion substitution in the ceria lattice. The turnover frequency of WGS under the assumption of fully dispersed gold is the same for a variety of low-content gold–ceria preparations. The stability of gold–ceria in various gas compositions and temperatures was good. The most serious stability issue is formation of cerium hydroxycarbonate in shutdown operation. # 2004 Elsevier B.V. All rights reserved.
TL;DR: In this paper, the authors demonstrate bilayer source-drain (S-D) electrodes for organic thin film transistors (OTFTs), which consists of a transition metal oxide (MoO3,WO3 or V2O5) layer and a metal layer.
Abstract: We demonstrate bilayer source-drain (S-D) electrodes for organic thin film transistors (OTFT). The bilayer consists of a transition metal oxide (MoO3,WO3, or V2O5) layer and a metal layer. The metal oxide layer, directly contacting the organic semiconducting layer, serves as the charge-injection layer. The overcoated metal layer is responsible for the conduction of charge carriers. We found that the metal oxide layer coupled between pentacene and metal layers played an important role in improving the field-effect transistor characteristics of OTFTs. Devices with the bilayer S-D electrodes showed enhanced hole-injection compared to those with only metal electrode. High field-effect mobility of 0.4cm2∕Vs and on/off current ratios of 104 were obtained in the pentacene based TFTs using the bilayer S-D electrodes at a gate bias of −40V. The improvement is attributed to the reduction in the contact barrier and the prevention of metal diffusion into the organic layer and/or unfavorable chemical reaction between ...
TL;DR: It is concluded that such a large acceleration of electron dynamics within the metal oxide films of DSSCs may in general be detrimental to device efficiency due to the limited rate of dye regeneration by the redox couple and the implications of this conclusion for strategies to optimize device performance.
Abstract: We report a comparison of charge transport and recombination dynamics in dye-sensitized solar cells (DSSCs) employing nanocrystalline TiO(2) and SnO(2) films and address the impact of these dynamics upon photovoltaic device efficiency. Transient photovoltage studies of electron transport in the metal oxide film are correlated with transient absorption studies of electron recombination with both oxidized sensitizer dyes and the redox couple. For all three processes, the dynamics are observed to be 2-3 orders of magnitude faster for the SnO(2) electrode. The origins of these faster dynamics are addressed by studies correlating the electron recombination dynamics to dye cations with chronoamperometric studies of film electron density. These studies indicate that the faster recombination dynamics for the SnO(2) electrodes result both from a 100-fold higher electron diffusion constant at matched electron densities, consistent with a lower trap density for this metal oxide relative to TiO(2), and from a 300 mV positive shift of the SnO(2) conduction band/trap states density of states relative to TiO(2). The faster recombination to the redox couple results in an increased dark current for DSSCs employing SnO(2) films, limiting the device open-circuit voltage. The faster recombination dynamics to the dye cation result in a significant reduction in the efficiency of regeneration of the dye ground state by the redox couple, as confirmed by transient absorption studies of this reaction, and in a loss of device short-circuit current and fill factor. The importance of this loss pathway was confirmed by nonideal diode equation analyses of device current-voltage data. The addition of MgO blocking layers is shown to be effective at reducing recombination losses to the redox electrolyte but is found to be unable to retard recombination dynamics to the dye cation sufficiently to allow efficient dye regeneration without resulting in concomitant losses of electron injection efficiency. We conclude that such a large acceleration of electron dynamics within the metal oxide films of DSSCs may in general be detrimental to device efficiency due to the limited rate of dye regeneration by the redox couple and discuss the implications of this conclusion for strategies to optimize device performance.
TL;DR: In this article, the Ni-YSZ anode supported direct-methane SOFCs on methane fuel was described and power densities as high as 0.52 W/cm2 at 700 °C and 1.27 W/ cm2 at 800 °C were observed.
TL;DR: A critical review of the present state of the knowledge in the field of dc reactive magnetron sputtering of compound films is given in this article, where the conditions under which oxides are reactively sputtered with high deposition rates aD oxide achieving up to approximately 77% of that of a pure metal aD Me.
TL;DR: In this paper, the authors have studied hafnium oxide and aluminum oxide grown on gallium arsenide by atomic layer deposition and showed that as-deposited films are continuous and predominantly amorphous.
Abstract: High-performance metal-oxide-semiconductor field effect transistors (MOSFETs) on III–V semiconductors have long proven elusive. High-permittivity (high-κ) gate dielectrics may enable their fabrication. We have studied hafnium oxide and aluminum oxide grown on gallium arsenide by atomic layer deposition. As-deposited films are continuous and predominantly amorphous. A native oxide remains intact underneath HfO2 during growth, while thinning occurs during Al2O3 deposition. Hydrofluoric acid etching prior to growth minimizes the final interlayer thickness. Thermal treatments at ∼600°C decompose arsenic oxides and remove interfacial oxygen. These observations explain the improved electrical quality and increased gate stack capacitance after thermal treatments.
TL;DR: In this article, a thermochemical study of the temperature effects on the Zn-Cl-H 2 O system by means of potential-pH, solubility and species repartition diagrams is presented with the view to better understand the effect of temperature on the deposition mechanism and composition of zinc oxide thin films.