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Pulsed Laser Deposition (pulsed + laser_deposition)
Selected AbstractsOptimization of Cr8O21 targets for Pulsed Laser DepositionCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2005L. Tortet Abstract This work describes the preparation of Cr8O21 pellets with optimised mass density to be used as targets for Pulsed Laser Deposition (PLD) of chromium dioxide thin films. Cr8O21 is synthesised by thermal decomposition of CrO3, at 270 °C. An attempt to reduce the grain size of the Cr8O21 powder to the nanometer scale has been made in order to increase the density of the pressed and sintered pellets serving as targets. The morphology of those starting fine powders as well as of targets (before and after laser ablation) and the corresponding thin films were characterized and studied using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Raman spectroscopy. The composition of the films is a mixture of crystallised Cr2O3 and amorphous CrO2. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A General Approach for Fabricating Arc-Shaped Composite Nanowire Arrays by Pulsed Laser DepositionADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Yue Shen Abstract Here, a new method is demonstrated that uses sideways pulsed laser deposition to deliberately bend nanowires into a desired shape after growth and fabricate arc-shaped composite nanowire arrays of a wide range of nanomaterials. The starting nanowires can be ZnO, but the materials to be deposited can be metallic, semiconductor, or ceramic depending on the application. This method provides a general approach for rational fabrication of a wide range of side-by-side or "core,shell" nanowire arrays with controllable degree of bending and internal strain. Considering the ZnO is a piezoelectric and semiconductive material, its electrical properties change when deformed. This technique has potential applications in tunable electronics, optoelectronics, and piezotronics. [source] Novel Fabrication of Ca-Doped LaNbO4 Thin-Film Proton-Conducting Fuel Cells by Pulsed Laser DepositionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2010Anna Magrasó Thin films of 0.5% Ca-doped La0.995Ca0.005NbO4,, (LCNO) proton-conducting electrolytes of ,2 ,m thickness were obtained by pulsed laser deposition on NiO,LaNbO4 composite substrates. The morphology of the films was granular after annealing at T,1000°C and evolved to spherical-like grains at 1100°C and above. The structure and composition of the films were characterized by X-ray diffraction and X-ray photoelectron spectrocopy. LCNO films showed the monoclinic fergusonite-type structure at room temperature. The area-specific resistance for a ,2-,m-thick electrolyte was in the order of 0.4 ,·cm2 at 600°C based on estimates of the electrode area. Temperature dependency of the electrical conductivity at 600°,700°C was comparable with that of bulk disks of the material. [source] Photobleaching of Ga2S3 -GeS2 films prepared with pulsed laser depositionLASER PHYSICS LETTERS, Issue 5 2007A. Tverjanovich Abstract Influence of the illumination with energy above band gap on optical properties of the thin (x)(Ga2S3)(1-x)(GeS2) films prepared with Pulsed Laser Deposition was investigated. Observed photo-induced bleaching is due to photo-oxidation of Ge and possible Ga atoms. Increasing of Ga content in the film results in increasing of the bleaching effect. This process is limited by the rate of diffusion of oxygen. (© 2007 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] Investigation of ZnTe thin films grown by Pulsed Laser Deposition methodPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 5 2007B. Kotlyarchuk Abstract This paper is devoted to optimization of the Pulsed Laser Deposition (PLD) growth condition of ZnTe films on various substrates and subsequent investigation of relevant parameters of growth process, structural, optical and electrical properties of grown films. Studies of the effect of growth parameters on the structural quality and properties of grown films were carried out. X-ray diffraction measurements showed that the ZnTe films, which have been deposited at optimal substrate temperatures, were characterized by a (111) preferred orientation with large average grain size. The optical transmission and reflectance in the energy range 1.5,5.5 eV for films grown at various substrate temperatures were measured. We calculated the variation in the absorption coefficient with the photon energy from the transmittance spectrum for samples grown at various substrate temperatures. Obtained data were analyzed and the value of the absorption coefficient, for allowed direct transitions, has been determined as a function of photon energy. We found that the undoped ZnTe films, which were grown by the PLD method, are typically p-type and possess resistivity in the range of 103 , cm at room temperature. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Electrical Properties of MIS Capacitors with AlN Films Synthesized by Pulsed Laser DepositionPLASMA PROCESSES AND POLYMERS, Issue 2 2006Silvia Bakalova Abstract Summary: We manufactured for the first time MIS capacitors based on aluminium nitride (AlN) thin films synthesized by Pulsed Laser Deposition (PLD). AlN films were deposited on Si substrates by PLD from AlN targets in nitrogen ambient by multi-pulse ablation using a UV KrF excimer laser source (,,=,248 nm, ,,=,7 ns). The structures we prepared were electrically characterized by C-V and I-V complementary measurements. Our studies evidence the formation of good interfaces, and of defects into the film bulk which are electrically active. This justifies further developments in view of future applications of PLD synthesized AlN thin films as a dielectric alternatives to SiO2. The distribution of the interface trap densities (Dit) in Si bandgap for AlN/Si structures synthesized at different N2 pressures. [source] Advances of pulsed laser deposition of ZnO thin filmsANNALEN DER PHYSIK, Issue 1-2 2004M. Lorenz Abstract Advances in Pulsed Laser Deposition (PLD) equipment and process design for the epitaxy of ZnO thin films on a-, and c-oriented sapphire substrates are reported. The achieved improvement of device relevant ZnO layer properties is directly related to our equipment design and novel process schemes. First results on growth and reflectivity of ZnO-MgO based dielectric Bragg resonators for future ZnO-based light emitter devices are shown. [source] Synthesis and Characterization of Superconducting ,-Mo2N Crystalline Phase on a Si Substrate: An Application of Pulsed Laser Deposition to Nitride Chemistry.CHEMINFORM, Issue 8 2006Kei Inumaru Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF. [source] Properties of InAs co-doped ZnO thin films prepared by pulsed laser depositionCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2009J. Elanchezhiyan Abstract InAs co-doped ZnO films were grown on sapphire substrates by pulsed laser deposition. The grown films have been characterized using X-ray diffraction (XRD), Hall effect measurements, Atomic force microscope (AFM) and Field emission scanning electron microscope (FESEM) in order to investigate the structural, electrical, morphological and elemental properties of the films respectively. XRD analysis showed that all the films were highly orientated along the c-axis. It was observed from Hall effect measurements that InAs co-doped ZnO films were of n-type conductivity. In addition, the presence of In and As has been confirmed by Energy dispersive X-ray analysis. AFM images revealed that the surface roughness of the films was decreased upon the co-doping. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Anomalous Oxidation States in Multilayers for Fuel Cell ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 16 2010James M. Perkins Abstract Significant recent interest has been directed towards the relationship between interfaces and reports of enhanced ionic conductivity. To gain a greater understanding of the effects of hetero-interfaces on ionic conductivity, advanced analytical techniques including electron microscopy (TEM/STEM), electron energy loss spectroscopy (EELS), and secondary ion mass spectrometry (SIMS) are used to characterize CeO2/Ce0.85Sm0.15O2 multilayer thin films grown by pulsed laser deposition. High quality growth is observed, but ionic conductivity measured by impedance spectroscopy and 18O tracer experiments is consistent with bulk materials. EELS analysis reveals the unusual situation of layers containing only Ce(IV) adjacent to layers containing both Ce(III) and Ce(IV). Post oxygen annealing induced oxygen diffusion and mixed oxidation states in both layers, but only in the vicinity of low angle grain boundaries perpendicular to the layers. The implications of the anomalous behavior of the Ce oxidation states on the design of novel electrolytes for solid oxide fuel cells is discussed. [source] A General Approach for Fabricating Arc-Shaped Composite Nanowire Arrays by Pulsed Laser DepositionADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Yue Shen Abstract Here, a new method is demonstrated that uses sideways pulsed laser deposition to deliberately bend nanowires into a desired shape after growth and fabricate arc-shaped composite nanowire arrays of a wide range of nanomaterials. The starting nanowires can be ZnO, but the materials to be deposited can be metallic, semiconductor, or ceramic depending on the application. This method provides a general approach for rational fabrication of a wide range of side-by-side or "core,shell" nanowire arrays with controllable degree of bending and internal strain. Considering the ZnO is a piezoelectric and semiconductive material, its electrical properties change when deformed. This technique has potential applications in tunable electronics, optoelectronics, and piezotronics. [source] Vertically Aligned Nanocomposite Thin Films as a Cathode/Electrolyte Interface Layer for Thin-Film Solid Oxide Fuel CellsADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Jongsik Yoon Abstract A thin layer of a vertically aligned nanocomposite (VAN) structure is deposited between the electrolyte, Ce0.9Gd0.1O1.95 (CGO), and the thin-film cathode layer, La0.5Sr0.5CoO3 (LSCO), of a thin-film solid-oxide fuel cell (TFSOFC). The self-assembled VAN nanostructure contains highly ordered alternating vertical columns of CGO and LSCO formed through a one-step thin-film deposition process that uses pulsed laser deposition. The VAN structure significantly improves the overall performance of the TFSOFC by increasing the interfacial area between the electrolyte and cathode. Low cathode polarization resistances of 9,×,10,4 and 2.39,, were measured for the cells with the VAN interlayer at 600 and 400,°C, respectively. Furthermore, anode-supported single cells with LSCO/CGO VAN interlayer demonstrate maximum power densities of 329, 546, 718, and 812,mW cm,2 at 550, 600, 650, and 700,°C, respectively, with an open-circuit voltage (OCV) of 1.13,V at 550,°C. The cells with the interlayer triple the overall power output at 650,°C compared to that achieved with the cells without an interlayer. The binary VAN interlayer could also act as a transition layer that improves adhesion and relieves both thermal stress and lattice strain between the cathode and the electrolyte. [source] Optimized La0.6Sr0.4CoO3,, Thin-Film Electrodes with Extremely Fast Oxygen-Reduction KineticsADVANCED FUNCTIONAL MATERIALS, Issue 19 2009Judith Januschewsky Abstract La0.6Sr0.4CoO3,, (LSC) thin-film electrodes are prepared on yttria-stabilized zirconia (YSZ) substrates by pulsed laser deposition at different deposition temperatures. The decrease of the film crystallinity, occurring when the deposition temperature is lowered, is accompanied by a strong increase of the electrochemical oxygen exchange rate of LSC. For more or less X-ray diffraction (XRD)-amorphous electrodes deposited between ca. 340 and 510,°C polarization resistances as low as 0.1,, cm2 can be obtained at 600,°C. Such films also exhibit the best stability of the polarization resistance while electrodes deposited at higher temperatures show a strong and fast degradation of the electrochemical kinetics (thermal deactivation). Possible reasons for this behavior and consequences with respect to the preparation of high-performance solid oxide fuel cell (SOFC) cathodes are discussed. [source] Periodic TiO2 Nanorod Arrays with Hexagonal Nonclose-Packed Arrangements: Excellent Field Emitters by Parameter OptimizationADVANCED FUNCTIONAL MATERIALS, Issue 15 2009Yue Li Abstract Periodic TiO2 nanorod arrays with hexagonal nonclose-packed (hncp) arrangements are synthesized by pulsed laser deposition (PLD) using polystyrene colloidal monolayers as templates and with subsequent annealing in air. The hncp-array formation is governed by in situ volume shrinkage of amorphous TiO2 nanorods in the crystallizing process during annealing. The array periodicity can easily be tuned by different sphere sizes of the colloidal template, whereas the distance between neighboring nanorods can be controlled by altering the background gas pressure during the PLD process, at a given periodicity for the nanorod array. Parameter-controlled growth is helpful for investigating and optimizing the parameter-dependent field-emission properties. The hncp nanorod array exhibits an enhanced field-emission (FE) performance compared to both particle films and nanorod arrays with top aggregation. With an increase in periodicity of a hncp nanorod array, the field-enhancement factor decreases and the turn-on FE field increases. FE characteristics can be further enhanced by increasing the distance between adjacent nanorods while maintaining the same periodicity. The parameter-optimized results suggest that the arrays with a smaller periodicity and a larger distance display the best FE performance and could be highly valuable for designing field-emission devices based on these periodic nanorod arrays. [source] Photoelectrochemical Study of Nanostructured ZnO Thin Films for Hydrogen Generation from Water SplittingADVANCED FUNCTIONAL MATERIALS, Issue 12 2009Abraham Wolcott Abstract Photoelectrochemical cells based on traditional and nanostructured ZnO thin films are investigated for hydrogen generation from water splitting. The ZnO thin films are fabricated using three different deposition geometries: normal pulsed laser deposition, pulsed laser oblique-angle deposition, and electron-beam glancing-angle deposition. The nanostructured films are characterized by scanning electron microscopy, X-ray diffraction, UV-vis spectroscopy and photoelectrochemical techniques. Normal pulsed laser deposition produces dense thin films with ca. 200,nm grain sizes, while oblique-angle deposition produces nanoplatelets with a fishscale morphology and individual features measuring ca. 900 by 450,nm on average. In contrast, glancing-angle deposition generates a highly porous, interconnected network of spherical nanoparticles of 15,40,nm diameter. Mott-Schottky plots show the flat band potential of pulsed laser deposition, oblique-angle deposition, and glancing-angle deposition samples to be ,0.29, ,0.28 and +0.20,V, respectively. Generation of photocurrent is observed at anodic potentials and no limiting photocurrents were observed with applied potentials up to 1.3,V for all photoelectrochemical cells. The effective photon-to-hydrogen efficiency is found to be 0.1%, 0.2% and 0.6% for pulsed laser deposition, oblique-angle deposition and glancing-angle deposition samples, respectively. The photoelectrochemical properties of the three types of films are understood to be a function of porosity, crystal defect concentration, charge transport properties and space charge layer characteristics. [source] Functional Perovskites , From Epitaxial Films to Nanostructured Arrays,ADVANCED FUNCTIONAL MATERIALS, Issue 24 2008Ionela Vrejoiu Abstract Functional perovskite materials gain increasing significance due to their wide spectrum of attractive properties, including ferroelectric, ferromagnetic, conducting and multiferroic properties. Due to the developments of recent years, materials of this type can conveniently be grown, mainly by pulsed laser deposition, in the form of epitaxial films, multilayers, superlattices, and well-ordered arrays of nanoislands. These structures allow for investigations of preparation,microstructure,property relations. A wide variation of the properties is possible, determined by strain, composition, defect contents, dimensional effects, and crystallographic orientation. An overview of our corresponding work of recent years is given, particularly focusing on epitaxial films, superlattices and nanoisland arrays of (anti)ferroelectric and multiferroic functional perovskites. [source] Formation of Metal Nano- and Micropatterns on Self-Assembled Monolayers by Pulsed Laser Deposition Through Nanostencils and Electroless Deposition,ADVANCED FUNCTIONAL MATERIALS, Issue 10 2006A. Speets Abstract Patterns of noble-metal structures on top of self-assembled monolayers (SAMs) on Au and SiO2 substrates have been prepared following two approaches. The first approach consists of pulsed laser deposition (PLD) of Pt, Pd, Au, or Cu through nano- and microstencils. In the second approach, noble-metal cluster patterns deposited through nano- and microstencils are used as catalysts for selective electroless deposition (ELD) of Cu. Cu structures are grown on SAMs on both Au and SiO2 substrates and are subsequently analyzed using X-ray photoelectron spectroscopy element mapping, atomic force microscopy, and optical microscopy. The combination of PLD through stencils on SAMs followed by ELD is a new method for the creation of (sub)-micrometer-sized metal structures on top of SAMs. This method minimizes the gas-phase deposition step, which is often responsible for damage to, or electrical shorts through, the SAM. [source] Intrinsic Ferroelectric Properties of Strained Tetragonal PbZr0.2Ti0.8O3 Obtained on Layer,by,Layer Grown, Defect,Free Single,Crystalline Films,ADVANCED MATERIALS, Issue 13 2006I. Vrejoiu Ferroelectric single,crystalline PbZr0.2Ti0.8O3 thin films, free from extended defects, are grown by pulsed laser deposition onto vicinal SrTiO3(001) single crystals. The PbZr0.2Ti0.8O3 films are strained and exhibit enhanced tetragonality, c/a,,,1.06. They have a remnant polarization, Pr,,,110,,C,cm,2, dielectric constant, ,33,,,90, and piezoelectric coefficient, d33, up to 50,pm,V,1 (see figure). [source] Polarization switching in BaTiO3 thin films measured by X-ray diffraction exploiting anomalous dispersionJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2004S. J. Van Reeuwijk Films of BaTiO3 ranging from 20,nm to 300,nm in thickness were grown with pulsed laser deposition on Nb:SrTiO3. The quality of the layers was investigated using atomic force microscopy, X-ray reflectivity and X-ray diffraction. Both the micrographs and the X-ray reflectivity spectra indicate a smooth surface of the layers. The X-ray diffraction profiles measured using synchrotron radiation show features characteristic for highly crystalline thin films. The application of an external electric field parallel to the c axis changes an hkl reflection of BaTiO3 to an hk reflection. Due to the anomalous dispersion, the intensities of these two reflections are not equal and the atomic displacements can be determined from the intensity differences. The electric field-induced intensity changes can be as large as a few percent, which makes data collection from a 100,nm film using Cu K, radiation from an X-ray tube feasible. The ,I/I values of a number of reflections from the 20 and 50,nm films were measured using synchrotron radiation. The observed ,I/I values were in good agreement with the intensity changes expected for polarization switching in the bulk. [source] Implant Surface Modification Using Laser Guided Coatings: In Vitro Comparison of Mechanical PropertiesJOURNAL OF PROSTHODONTICS, Issue 5 2008Asvin Vasanthan DDS Abstract Purpose: Plasma-sprayed hydroxyapatite (HA)-coated implants show failures along the coating,substrate interface due to poor bond strength. We analyzed HA coatings obtained by pulsed laser deposition (PLD) and compared them to commercially used plasma-sprayed coatings with respect to their bond strength to titanium alloy (Ti-6Al-4V), as well as surface roughness alterations produced by each of the two deposition methods. Materials and Methods: Twelve titanium alloy disks were plasma-sprayed under commercial implant coating conditions, and 24 titanium alloy disks were coated using PLD. All coatings were characterized by the presence of the different calcium phosphate (CaP) phases. The plasma-sprayed coatings (n = 12) were predominantly HA, and the pulsed laser-deposited coatings were hydroxydyapatite (n = 12) and HA coating with a tetra calcium phosphate (TTCP) phase (n = 12). The surface roughness was analyzed before and after the coating processes to assess roughness changes to the surface by the coatings. The adhesive bond strengths of these coatings to the substrate titanium alloy was tested and compared. Scheffé's test was used to analyze the statistical significance of the data. Results: The surface roughness alteration following PLD was a decrease of 0.2 ,m, whereas following plasma spraying the decrease was 1.0 ,m. Bond strengths were as follows [mean (SD) in MPa]: pulsed laser-deposited HA coatings: 68.3 (17.8); pulsed laser-deposited HA with tetra-CaP: 55.2 (21.1); plasma-sprayed HA 17.0 (2.8). The multivariate Scheffé's test revealed that HA coatings obtained by PLD had significantly increased bond strengths compared with the plasma sprayed ones (p, 0.05). Conclusions: HA coatings obtained by PLD showed greater adherence to titanium alloy. PLD offers an alternative method to produce thinner coatings with better adherence properties, along with precise control over the deposition process. [source] Orientation and Phase Relationships between Titania Films and Polycrystalline BaTiO3 Substrates as Determined by Electron Backscatter Diffraction MappingJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2010Nina V. Burbure Titania films have been grown on polycrystalline BaTiO3 (BTO) substrates at 700°C by pulsed laser deposition. Electron backscatter diffraction (EBSD) was used to determine grain orientations in the substrate before growth, and the phase and orientation of the supported films after growth. All BaTiO3 grains within 26° of (001) were covered by anatase films with an orientation relationship of (001)Anatase||(001)BTO and [100]Anatase||[100]BTO. Rutile with a variety of orientations grew on BaTiO3 grains with orientations closer to (110) and (111). EBSD mapping provides an efficient means for determining phase and orientation relationships of films over all orientation parameters. [source] Novel Fabrication of Ca-Doped LaNbO4 Thin-Film Proton-Conducting Fuel Cells by Pulsed Laser DepositionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2010Anna Magrasó Thin films of 0.5% Ca-doped La0.995Ca0.005NbO4,, (LCNO) proton-conducting electrolytes of ,2 ,m thickness were obtained by pulsed laser deposition on NiO,LaNbO4 composite substrates. The morphology of the films was granular after annealing at T,1000°C and evolved to spherical-like grains at 1100°C and above. The structure and composition of the films were characterized by X-ray diffraction and X-ray photoelectron spectrocopy. LCNO films showed the monoclinic fergusonite-type structure at room temperature. The area-specific resistance for a ,2-,m-thick electrolyte was in the order of 0.4 ,·cm2 at 600°C based on estimates of the electrode area. Temperature dependency of the electrical conductivity at 600°,700°C was comparable with that of bulk disks of the material. [source] Photobleaching of Ga2S3 -GeS2 films prepared with pulsed laser depositionLASER PHYSICS LETTERS, Issue 5 2007A. Tverjanovich Abstract Influence of the illumination with energy above band gap on optical properties of the thin (x)(Ga2S3)(1-x)(GeS2) films prepared with Pulsed Laser Deposition was investigated. Observed photo-induced bleaching is due to photo-oxidation of Ge and possible Ga atoms. Increasing of Ga content in the film results in increasing of the bleaching effect. This process is limited by the rate of diffusion of oxygen. (© 2007 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source] PS-NH2 + PMMA-COOH blend: A promising substrate material for the deposition of densely packed gold nanoparticlesPHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 3-4 2010D. K. Bo Abstract Densely packed gold nanoparticles with narrow size distribution were fabricated by pulsed laser deposition using a blend of amino-terminated polystyrene (PS-NH2) and carboxyl-terminated polymethylmethacrylate (PMMA-COOH) as a deposition substrate. Transmission electron microscopy showed spherical Au nanoparticles with an average size of 5 nm. UV,vis absorption spectra of the Au/blend nanocomposite films exhibited a strong resonance band at 658 nm. The analyses of the spectrum using the effective medium Bergman theory showed that the nanocomposite is comprised of isolated and randomly arranged nanoparticles. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Low-temperature growth of high quality AlN films on carbon face 6H-SiCPHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 1 2008Myunghee Kim Abstract AlN films have been grown on atomically flat carbon face 6H-SiC (000) substrates by pulsed laser deposition and their structural properties have been investigated. In-situ reflection high-energy electron diffraction observations have revealed that growth of AlN at 710 °C proceeds in a Stranski,Krastanov mode, while typical layer-by-layer growth occurs at room temperature (RT) with atomically flat surfaces. It has been revealed that the crystalline quality of the AlN film is dramatically improved by the reduction in growth temperature down to RT and the full width at half maximum values in the X-ray rocking curves for 0004 and 102 diffractions of the RT-grown AlN film are 0.05° and 0.07°, respectively. X-ray reciprocal space mapping has revealed that the introduction of misfit dislocations is suppressed in the case of RT growth, which is probably responsible for the improvement in crystalline quality. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Textured growth and microstructure of pulsed laser deposited Nb/Cr/SmCo5 hybrid structuresPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2010R. Schaarschuch Abstract Hybrid structures based on superconducting Nb and highly coercive ferromagnetic SmCo5 films grown on MgO(100) substrates were fabricated by pulsed laser deposition under UHV conditions. Thin film architectures of SmCo5 on Nb and the reversed system both with and without Cr spacer layer between superconductor and ferromagnet were examined by transmission electron microscopy and X-ray diffraction concerning their microstructure and epitaxial relationship, respectively. For SmCo5 on Nb with thick intermediate Cr spacer the epitaxial relationship MgO(001)[100]//Cr(001)[110]//Nb(001)[110]//Cr(001)[110]//SmCo5(11,,,20)[0001]//Cr(001)[110] was found. With decreasing thickness of the Cr spacer layer the strength of the texture decreases and finally crystallinity of SmCo5 is lost. In the reversed layer system, Nb on Cr on SmCo5, with decreasing thickness of the Cr spacer layer the epitaxial relationships change from SmCo5(11,,,20)[0001]//Nb(001)[110] to local SmCo5(11,,,20) [0001]//Nb(110)[1,,,11] and the Nb texture changes from the (001)[110] component to a ,110, fibre. The orientation relationships observed are discussed with regard to elastic strain energy minimization. [source] A comprehensive investigation of the structural properties of ferroelectric PbZr0.2Ti0.8O3 thin films grown by PLDPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2009David Walker Abstract X-Ray diffraction investigations were made of high-quality epitaxial thin films of the ferroelectric material lead zirconate titanate, PbZr0.2Ti0.8O3 (PZT), grown by pulsed laser deposition (PLD). Layers from 7 to 200,nm in thickness were studied, deposited on a 30,nm SrRuO3 (SRO) electrode on a [001] oriented SrTiO3 (STO) substrate. The out-of-plane lattice parameters of the PZT films were measured by high-resolution X-ray diffraction using CuK,1 radiation. A significant enhancement of the c lattice parameter with film thickness was observed, the maximum value of 4.25,Å reached in the 30,50,nm thick films. For film thicknesses greater than 100,nm, the c lattice parameter is relaxed, towards the bulk value of 4.13,Å at this composition. The in-plane lattice parameters were studied by Grazing incidence X-ray scattering (GIXS), using 15,keV synchrotron radiation at I16, Diamond. The a lattice parameter of domains with [001] oriented normal to the sample surface was effectively lattice matched to the SRO layer in the 7,nm ultra-thin film, but relaxed compared to the SRO in thicker films. The tetragonality of the [001] oriented domains decreases with increasing film thickness, approaching the bulk value of 1.05 in the thickest films. Evidence for the presence of [100] oriented a -domains was found in PZT films as thin as 30,nm, the proportion of which increased with increasing film thickness, suggesting they grow in order to relieve stresses that would prevent the epitaxial growth of thicker PZT films. The a -domains in the thicker films were found to be located nearer to the PZT/SRO interface than to the top surface of the PZT. [source] Crystalline ZnO/SrTiO3 transparent field effect transistorPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2008E. Bellingeri Abstract We fabricated field effect transistors which are transparent at visible wavelength, by realizing epitaxial ZnO/SrTiO3 heterostructures. High crystalline quality ZnO layers were grown by pulsed laser deposition on 110 oriented strontium titanate single crystals. By conventional photolithographic techniques we realized micrometric sized devices in both bottom-gate stacked layers geometry and planar side-gate configuration. Our transistors show 80% light transmittance, on/off ratios up to 106 and field effect mobilities up to 30 cm2/Vs at 77 K. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effects of growth temperature on exciton lifetime and structural properties of ZnO films on sapphire substratePHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 15 2006S. Cho Abstract We report on optimization of growth conditions by studying the structural and optical properties of ZnO films grown on sapphire substrate by pulsed laser deposition at different growth temperatures. The crystallographic structure and surface morphology were studied by X-ray diffraction and atomic force microscopy, respectively. The flattest surface was observed in the sample grown at substrate temperature of 500 °C. The optical characterization was performed by steady state and time resolved photoluminescence spectroscopy. Photoluminescence of the samples was studied at low CW excitation and at high-power-density pulsed excitation in picosecond domain. Stimulated emission was observed at pulsed excitation. Carrier lifetimes were found to significantly depend on the growth temperature reaching the peak value also in the samples grown at approximately 500 °C. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Growth and characterization of Sn doped ZnO thin films by pulsed laser depositionPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2006E. López-Ponce Abstract Sn:ZnO thin films with different Sn concentrations were grown by pulsed laser deposition (PLD) onto single-crystal Si(001) substrates at an oxygen pressure of 2 × 10,2 mbar and substrate temperature of 600 °C. The targets used were high density Sn:ZnO pellets with different Sn concentrations produced by mixing ZnO and SnO2 by conventional ceramic routes. A deep structural and electrical characterization was carried out in order to determine the role of an increasing Sn nominal concentration on the ZnO film transport properties. Only films with a nominal 0.1 at% Sn show an improvement of the transport properties, lower resistivity and higher donor concentration, with respect to pure ZnO thin films. For films with larger Sn nominal concentrations segregated SnZnO phases appear that lead to larger film resistivities and no increase in donor concentration. The 0.1 at% Sn film is accordingly a good candidate to study the possible room temperature ferromagnetism when co doping with Mn. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||||||||||||||||||||