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Oxide Thin Films (oxide + thin_film)
Kinds of Oxide Thin Films Selected AbstractsTime,Temperature,Transformation (TTT) Diagrams for Crystallization of Metal Oxide Thin FilmsADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Jennifer L. M. Rupp Abstract Time,temperature,transformation (TTT) diagrams are proposed for the crystallization of amorphous metal oxide thin films and their specific characteristics are discussed in comparison to glass-based materials, such as glass-ceramics and metallic glasses. The films crystallize from amorphous to full crystallinity in the solid state. As an example the crystallization kinetics for a single-phase metal oxide, ceria, and its gadolinia solid solutions are reported made by the precipitation thin-film method spray pyrolysis. The crystallization of an amorphous metal oxide thin film generally follows the Lijschitz,Sletow,Wagner (LSW) Ostwald ripening theory: Below the percolation threshold of 20 vol% single grains crystallize in the amorphous phase and low crystallization rates are measured. In this state no impact of solute on crystallization is measurable. Once the grains form primary clusters above the threshold the solute slows down crystallization (and grain growth) thus shifting the TTT curves of the doped ceria films to longer times and higher temperatures in comparison to undoped ceria. Current views on crystallization of metal oxide thin films, the impact of solute dragging, and primary TTT diagrams are discussed. Finally, examples on how to use these TTT diagrams for better thermokinetic engineering of metal oxide thin films for MEMS are given, for example, for micro-Solid Oxide Fuel Cells and resistive sensors. In these examples the electrical properties depend on the degree of crystallinity and, thereby, on the TTT conditions. [source] The Materials Science of Functional Oxide Thin Films,ADVANCED MATERIALS, Issue 38-39 2009Mark G. Blamire Abstract Research in the area of functional oxides has progressed from study of their basic chemistry and structure to the point at which an enormous range of desirable properties are being explored for potential applications. The primary limitation on exploitation is the difficulty of achieving sufficiently precise control of the properties because of the range of possible defects in such materials and the remarkably strong effect of such defects on the properties. This review outlines the reasons underlying this sensitivity and recent results that demonstrate the levels of control which are now possible. [source] Microelectromechanical Systems: All-Oxide Crystalline Microelectromechanical Systems: Bending the Functionalities of Transition-Metal Oxide Thin Films (Adv. Mater.ADVANCED MATERIALS, Issue 23 200923/2009) Freestanding structures can be employed to induce strain at their surfaces upon bending. Luca Pellegrino and co-workers show on p. 2377 that a crystalline SrTiO3 (001) thin film cantilevered structure that can be used as a flexible substrate for the epitaxial deposition of correlated oxide films. Surface strain generated by bending is transmitted to the epitaxial (La,Sr)MnO3 film producing a reversible change of its electrical resistance. [source] All-Oxide Crystalline Microelectromechanical Systems: Bending the Functionalities of Transition-Metal Oxide Thin FilmsADVANCED MATERIALS, Issue 23 2009Luca Pellegrino A crystalline all-oxide microelectromechanical system is presented. A suspended SrTiO3(001) cantilever is employed as flexible substrate for the deposition of epitaxial transition-metal oxide films. A strain generator device for oxide films is thus demonstrated, changing the conductivity of an overgrown epitaxial (La,Sr-)-MnO3 film by bending downward the SrTiO3 element with an AFM tip or a gate voltage bias. [source] Effects of Individual Layer Thickness on the Microstructure and Optoelectronic Properties of Sol,Gel-Derived Zinc Oxide Thin FilmsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2008Noureddine Bel Hadj Tahar Zinc oxide (ZnO) thin films were prepared under different conditions on glass substrates using a sol,gel process. The microstructure of ZnO films was investigated by means of diffraction analysis, and plan-view and cross-sectional scanning electron microscopy. It was found that the preparation conditions strongly affected the structure and the optoelectronic properties of the films. A structural evolution in morphology from spherical to columnar growth was observed. The crystallinity of the films was improved and columnar film growth became more dominant as the zinc concentration and the substrate withdrawal speed decreased. The individual layer thickness for layer-by-layer homoepitaxy growth that resulted in columnar grains was <20 nm. The grain columns are grown through the entire film with a nearly unchanged lateral dimension through the full film thickness. The columnar ZnO grains are c -axis oriented perpendicular to the interface and possess a polycrystalline structure. Optical transmittance up to 90% in the visible range and electrical resistivity as low as 6.8 × 10,3·,·cm were obtained under optimal deposition conditions. [source] Preparation of Molybdenum, Vanadium, and Tungsten Oxide Thin Films from Self-Assembly Deposited Polyoxometalate,Alkylamine-Layered Hybrid FilmsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2007Tetsuya Kida A novel, simple, and efficient route for preparing MoO3, V2O5, and WO3 films has been developed from layered polyoxometallate (POM)-alkylamine hybrid films by calcination. The highly ordered hybrid films were self-assembly deposited in a one-step process using clear precursor POM solutions, prepared by reacting layered MoO3, V2O5, and WO3·H2O powders with hexylamine in the presence of water. The morphology of the resulting films can be tuned by removing the intercalated hexylamine molecules from the as-prepared hybrid films through UV irradiation before calcination. [source] Nanocrystalline Tin Oxide Thin Films via Liquid Flow DepositionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2003Sitthisuntorn Supothina Nanocrystalline films of SnO2 were deposited by liquid flow deposition (LFD), i.e., by flowing aqueous solutions of SnCl4·5H2O and HCl over single-crystalline silicon substrates at 80°C. The substrates were either oxidized and fully hydrolyzed (bare silicon) or oxidized, hydrolyzed, and then coated with siloxy-anchored organic self-assembled monolayers (SAMs). Continuous, adherent films formed on sulfonate- and thioacetate-functionalized SAMs; adherent but sometimes discontinuous films formed on bare silicon and methyl-functionalized SAMs. The films contained equiaxed cassiterite crystals, ,4,10 nm in size. The film thickness increased linearly with deposition time. The maximum growth rate observed was 85 nm·h,1 on sulfonate SAM, and the maximum film thickness obtained was 1 ,m. A new dimensionless parameter, the normalized residence time, ,, was introduced for the purpose of interpreting the influence of solution conditions (i.e., degree of supersaturation, as controlled via pH, and tin concentration) and flow characteristics (flow rate and the configuration of the deposition chamber) on the growth rate in LFD processes. The results were consistent with a particle attachment mechanism for film growth and inconsistent with heterogeneous nucleation on the substrate. [source] Electrical Conductivity and Lattice Defects in Nanocrystalline Cerium Oxide Thin FilmsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2001Toshio Suzuki The results of the electrical conductivity and Raman scattering measurements of CeO2 thin films obtained by a polymeric precursor spin-coating technique are presented. The electrical conductivity has been studied as a function of temperature and oxygen activity and correlated with the grain size. When compared with microcrystalline samples, nanocrystalline materials show enhanced electronic conductivity. The transition from extrinsic to intrinsic type of conductivity has been observed as the grain size decreases to <100 nm, which appears to be related to a decrease in the enthalpy of oxygen vacancy formation in CeO2. Raman spectroscopy has been used to analyze the crystalline quality as a function of grain size. A direct comparison has been made between the defect concentration calculated from coherence length and nonstoichiometry determined from electrical measurements. [source] A Low-Temperature Molecular Approach to Highly Conductive Tin-Rich Indium Tin Oxide Thin Films with Durable Electro-Optical Performance,ANGEWANDTE CHEMIE, Issue 42 2009Yilmaz Aksu Dr. Spar Energie, lächle! Sehr gut leitende zinnreiche Indiumzinnoxid(ITO)-Komposite lassen sich aus der molekularen Vorstufe Sn(tBuO)3In einfach herstellen. Die nicht weiter bearbeiteten transparenten und hochleitenden dünnen Filme auf Glassubstraten sind atomar flach und liefern die bisher besten Ergebnisse in ITO-basierten Elektrolumineszenzanwendungen. [source] Growth of Praseodymium Oxide Thin Films by Liquid Injection MOCVD Using a Novel Praseodymium Alkoxide Precursor.CHEMINFORM, Issue 52 2003Helen C. Aspinall Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: High Li+ -Ion Storage Capacity and Double-Electrochromic Behavior of Sol,Gel-Derived Iron Oxide Thin Films with Sulfate Residues.CHEMINFORM, Issue 41 2001Zhongchun Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Crystallization and Grain Growth Kinetics for Precipitation-Based Ceramics: A Case Study on Amorphous Ceria Thin Films from Spray PyrolysisADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Jennifer L. M. Rupp Abstract The introductory part reviews the impact of thin film fabrication, precipitation versus vacuum-based methods, on the initial defect state of the material and microstructure evolution to amorphous, biphasic amorphous-nanocrystalline, and fully nanocrystalline metal oxides. In this study, general rules for the kinetics of nucleation, crystallization, and grain growth of a pure single-phase metal oxide thin film made by a precipitation-based technique from a precursor with one single organic solvent are discussed. For this a complete case study on the isothermal and non-isothermal microstructure evolution of dense amorphous ceria thin films fabricated by spray pyrolysis is conducted. A general model is established and comparison of these thin film microstructure evolution to kinetics of classical glass-ceramics or metallic glasses is presented. Knowledge on thermal microstructure evolution of originally amorphous precipitation-based metal oxide thin films allows for their introduction and distinctive microstructure engineering in devices-based on microelectromechanical (MEMS) technology such as solar cells, capacitors, sensors, micro-solid oxide fuel cells, or oxygen separation membranes on Si-chips. [source] Modification of Electronic Structures of a Carbon Nanotube by Hydrogen FunctionalizationADVANCED MATERIALS, Issue 24 2002K.S. Kim A rigorous method to engineer the electronic structure of carbon nanotubes from metallic to semiconducting is reported (see inside front cover). An intramolecular junction in carbon nanotube is fabricated, where half of the nanotube is masked by a silicon oxide thin film. Functionalization of the nanotube by atomic hydrogen leads to the formation of an intramolecular junction, resulting in clear rectifying behavior at room temperature. This represents an important step towards the practical realization of nanotube-based nanotransistors. [source] Time,Temperature,Transformation (TTT) Diagrams for Crystallization of Metal Oxide Thin FilmsADVANCED FUNCTIONAL MATERIALS, Issue 17 2010Jennifer L. M. Rupp Abstract Time,temperature,transformation (TTT) diagrams are proposed for the crystallization of amorphous metal oxide thin films and their specific characteristics are discussed in comparison to glass-based materials, such as glass-ceramics and metallic glasses. The films crystallize from amorphous to full crystallinity in the solid state. As an example the crystallization kinetics for a single-phase metal oxide, ceria, and its gadolinia solid solutions are reported made by the precipitation thin-film method spray pyrolysis. The crystallization of an amorphous metal oxide thin film generally follows the Lijschitz,Sletow,Wagner (LSW) Ostwald ripening theory: Below the percolation threshold of 20 vol% single grains crystallize in the amorphous phase and low crystallization rates are measured. In this state no impact of solute on crystallization is measurable. Once the grains form primary clusters above the threshold the solute slows down crystallization (and grain growth) thus shifting the TTT curves of the doped ceria films to longer times and higher temperatures in comparison to undoped ceria. Current views on crystallization of metal oxide thin films, the impact of solute dragging, and primary TTT diagrams are discussed. Finally, examples on how to use these TTT diagrams for better thermokinetic engineering of metal oxide thin films for MEMS are given, for example, for micro-Solid Oxide Fuel Cells and resistive sensors. In these examples the electrical properties depend on the degree of crystallinity and, thereby, on the TTT conditions. [source] Crystallization and Grain Growth Kinetics for Precipitation-Based Ceramics: A Case Study on Amorphous Ceria Thin Films from Spray PyrolysisADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Jennifer L. M. Rupp Abstract The introductory part reviews the impact of thin film fabrication, precipitation versus vacuum-based methods, on the initial defect state of the material and microstructure evolution to amorphous, biphasic amorphous-nanocrystalline, and fully nanocrystalline metal oxides. In this study, general rules for the kinetics of nucleation, crystallization, and grain growth of a pure single-phase metal oxide thin film made by a precipitation-based technique from a precursor with one single organic solvent are discussed. For this a complete case study on the isothermal and non-isothermal microstructure evolution of dense amorphous ceria thin films fabricated by spray pyrolysis is conducted. A general model is established and comparison of these thin film microstructure evolution to kinetics of classical glass-ceramics or metallic glasses is presented. Knowledge on thermal microstructure evolution of originally amorphous precipitation-based metal oxide thin films allows for their introduction and distinctive microstructure engineering in devices-based on microelectromechanical (MEMS) technology such as solar cells, capacitors, sensors, micro-solid oxide fuel cells, or oxygen separation membranes on Si-chips. [source] Impact of Defect Distribution on Resistive Switching Characteristics of Sr2TiO4 Thin FilmsADVANCED MATERIALS, Issue 3 2010Keisuke Shibuya The resistive switching properties of Sr2TiO4 thin films with specific defect distribution have been studied. Junctions of Sr2TiO4 thin films containing a high density of defects show well-pronounced resistive switching properties while those with well-ordered microstructure exhibited insignificant hysteresis windows. This work clearly demonstrates the crucial role of defects for the microscopic switching mechanisms in oxide thin films. [source] Nanoscale Writing of Transparent Conducting Oxide Features with a Focused Ion BeamADVANCED MATERIALS, Issue 6 2009Norma E. Sosa Embedded, optically transparent, electrically conducting oxide nanowires, and other patterns are written on highly resistive transparent metal oxide thin films with nanoscale spatial control using focused ion beam implantation. The resulting transparent conducting oxide features are 110-160 nm wide, 7 nm deep, and are theoretically limitless in length, connectivity, and shape. [source] Improved Aging Characteristics of NTC Thermistor Thin Films Fabricated by a Hybrid Sol,Gel,MOD ProcessJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2006Dmitry A. Kukuruznyak Negative temperature coefficient thermistor oxide thin films with improved aging characteristics are described. Better thermal stability has been achieved by incorporating sol,gel techniques with metallo-organic decomposition methods. A compositional range was identified whereby borosilicate may incorporate into the thermistor oxides, forming nanocomposites showing thermistor electrical characteristics. Thermistor thin films, with composition Ni0.48Co0.24Cu0.6Mn1.68O4·0.22SiO2·0.15B2O3 were deposited onto glass substrates from a solution containing organic transition metal salts, tetraethyl orthosilicate and triethyl borate. Electrical resistance measurements verified characteristic thermistor behavior. Nanocomposite thin films exhibited a factor of four improvement as compared with pure oxides after aging at 150°C for 500 h. [source] Preparation of ZnO thin film by the sol,gel method using low temperature ozone oxidationPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2010Takashi Ehara Abstract Zinc oxide thin films have been prepared by the sol,gel method from a 2-methoxyethanol solution of zinc acetate dihydrate on SiO2 substrates using air, pure oxygen, and 1% ozone in oxygen as oxygen source. In the cases where air or oxygen was used as the oxygen source for thermal annealing, samples annealed at 600 to 800,°C exhibit a (0002) peak in X-ray diffraction (XRD). A sample annealed at 700,°C exhibited the highest (0002) peak intensity in conventional thermal annealing. However, the case using 1% ozone in oxygen as the atmosphere presented different results. A sample treated in 1% ozone at 100,°C had peak intensity in XRD (0002) comparable with samples annealed at several hundreds of degree in air or oxygen. This result indicates that the high oxidation efficiency of ozone is useful in decreasing the processing temperature of the sol,gel method. [source] Hydrogen effects on crystallinity, photoluminescence, and magnetization of indium tin oxide thin films sputter-deposited on glass substrate without heat treatmentPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2010Suning Luo Abstract Indium tin oxide (ITO) thin films were sputter deposited by using working gas containing hydrogen on glass substrate without any heat treatments. The films demonstrated X-ray diffraction due to polycrystalline ITO, blue-green photoluminescence (PL) due to oxygen defects in nano-structured ITO crystals, and paramagnetic behaviour in temperature dependence of magnetization overlapped with diamagnetic signal from the substrate. The carrier density n of the films was of the order of 1020,cm,3, and varied as an inverse of V-character with the hydrogen concentration [H] in the gas. The n value peaked at [H],=,1%. Spectral features at ,430 and ,470,nm of the PL emission were invariant with [H]. The order of the density of electrons N with spins obeying the Curie law was 1023,cm,3, and the variation in N with [H] was almost parallel to that in n with [H]. [source] Growth and characterization of gallium oxide thin films by radiofrequency magnetron sputteringPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2008P. Marie Abstract Undoped and Neodymium-doped gallium oxide (Ga2O3) thin films of about 500 nm thickness were successfully grown at different temperatures ranging from 100 up to 600 °C by radiofrequency magnetron sputtering. Post-annealing treatments were carried out at 900 °C and 1000 °C. The obtained films were (400) textured and a grain size of a few tens of nanometres was found. Optical and electrical characterizations led to a figure of merit of about 1.9 × 10,4. These films were successfully doped with Neodymium by a co-sputtering method. The photoluminescence experiments for the Nd-doped ,-Ga2O3 films clearly showed the rare-earth emitting signature. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effect of oxygen partial pressure on optical and electrical properties of co-sputtered amorphous zinc indium tin oxide thin filmsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2008K. J. Saji Abstract Transparent thin films of amorphous zinc indium tin oxide were prepared at room temperature by co-sputtering of zinc oxide and indium tin oxide. Effect of oxygen partial pressure on the optical and electrical properties of amorphous zinc indium tin oxide thin films were investigated. Conductivity, carrier concentration and Hall mobility showed strong dependence on the oxygen partial pressure and these parameters decreased with the increase of oxygen pressure. The effect of subgap states caused a sharp difference in measured optical band gap values between the films deposited with and without oxygen partial pressure. Carrier transport studies were carried out by temperature dependent conductivity measurements. At low electron density, the conductivity showed thermally activated behaviour and at higher carrier concentrations it changed to almost degenerate band conduction. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Influence of annealing temperature on the structural and optical properties of sol,gel prepared ZnO thin filmsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2006Mingsong Wang Abstract Zinc oxide thin films have been prepared via a sol,gel process. The influence of annealing temperature on the structural and optical properties of the ZnO thin films has been investigated. The prepared ZnO thin films had a polycrystalline hexagonal wurtzite structure with no preferred orientation. The annealing temperature had a great effect on the optical properties of the ZnO thin films: the optical band gap became narrow due to the increase in crystallite size and the reduction in amorphous phase amount with increasing annealing temperature. Absorption or desorption of oxygen in the annealing process caused the observed yellow or green emission. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Nitridation and reoxidation of high- k metal oxide thin films using argon excimer sourcesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2006J. J. Yu Abstract We report for the first time the nitridation and reoxidation of metal oxide films with the active nitrogen and oxygen species produced by argon excimer sources. Preliminary results on 9 nm Ta2O5 films using this method exhibited excellent electrical properties with the leakage current density being up to 3 orders of magnitude lower than the as-deposited films. Breakdown fields were found to be greater than 13 MV/cm. Accumulation capacitance with the nitrided film increased by 25% compared with the as-deposited film. Optical transmittance was as high as 99% in the visible region and more than 74% in the UV region. The refractive index at 632.8 nm was high up to 2.2. The Ar excimer source emitted energetic VUV photons which could break nitrogen triple bonds to produce active nitrogen species and photodissociate O2 to form strong oxidant O3 and highly reactive O (1S) atoms, leading to the nitridation and reoxidation of Ta2O5 without the need for the use of H2O, NH3 and high temperature substrate heating. The nitridation process for a specific film thickness can be optimised by adjusting the VUV irradiation time to achieve increased accumulation capacitance and improved leakage property simultaneously. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Control of composition and structure of ferroelectric oxide thin films grown by pulsed laser depositionPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 10 2008Maryline Guilloux-Viry Abstract SrBi2Nb2O9 and KTa1,xNbxO3 high quality thin films were grown by pulsed laser deposition. An accurate optimization of deposition conditions is a prerequisite for the control of composition, mainly according to the high volatility of Bi and K. In order to take benefit of the ferroelectric characteristics for new microelectronic devices, thin films were epitaxially grown on various substrates and seed layers adapted to application requirements. For that purpose metal electrodes and ferroelectric oxides were associated in a planar capacitor geometry or in a coplanar configuration depending on the targeted applications. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Flux of Positive Ions and Film Growth in Reactive Sputtering of Al-Doped ZnO Thin FilmsPLASMA PROCESSES AND POLYMERS, Issue S1 2007Florian Ruske Abstract The reactive magnetron sputtering deposition of Al-doped zinc oxide thin films using a dual magnetron has been studied for a flux of positive ions and the total thermal load onto the substrate. The spatial distribution of both quantities has been studied using a thermal probe and a retarding field analyzer mounted onto a moveable carrier system. The positive ions were found to mostly originate from the plasma sheath at the substrate, with the spatial distribution determined by the plasma density distribution in the coating chamber. The total energy flux to the substrate mainly originated from the plasma, with positive ions only contributing a small part of the total plasma irradiation. In the tested conditions and with the coater examined, the quality of the deposited films mainly depends on oxygen distribution on the substrate and is not a direct consequence of the total energy flux to the substrate. [source] | ||||||||||||||||