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Silicon Oxide (silicon + oxide)
Selected AbstractsPrecise Structure of Pentacene Monolayers on Amorphous Silicon Oxide and Relation to Charge TransportADVANCED MATERIALS, Issue 22 2009Stefan C. B. Mannsfeld The precise molecular packing in pentacene monolayers on silicon oxide is determined for the first time using a combination of grazing incidence X-ray diffraction (GIXD) and crystallographic refinement calculations. The pentacene molecules are found to adopt a completely tilt-free herringbone motif, the charge-transport properties of which are discussed on the basis of density functional theory calculations. [source] Growth of Silicon Oxide in Thin Film Block Copolymer Scaffolds,ADVANCED MATERIALS, Issue 8 2004H. Kim Thin films of asymmetric diblock copolymers have been used as scaffolds to define an ordered array of nanometer-scale reaction vessels in which high density arrays of silicon oxide nanostructures (see Figure) are produced by exposure to silicon tetrachloride. Such site-specific silicon oxide nanostructures could have widespread uses for sensory and optoelectronic applications. [source] Viability study of HL60 cells in contact with commonly used microchip materialsELECTROPHORESIS, Issue 24 2006Floor Wolbers Abstract This paper presents a study in which different commonly used microchip materials (silicon oxide, borosilicate glass, and PDMS) were analyzed for their effect on human promyelocytic leukemic (HL60) cells. Copper-coated silicon was analyzed for its toxicity and therefore served as a positive control. With quantitative PCR, the expression of the proliferation marker Cyclin D1 and the apoptosis marker tissue transglutaminase were measured. Flow cytometry was used to analyze the distribution through the different phases of the cell cycle (propidium iodide, PI) and the apoptotic cascade (Annexin V in combination with PI). All microchip materials, with the exception of Cu, appeared to be suitable for HL60 cells, showing a ratio apoptosis/proliferation (Rap) comparable to materials used in conventional cell culture (polystyrene). These results were confirmed with cell cycle analysis and apoptosis studies. Precoating the microchip material surfaces with serum favor the proliferation, as demonstrated by a lower Rap as compared to uncoated surfaces. The Cu-coated surface appeared to be toxic for HL60 cells, showing over 90% decreased viability within 24,h. From these results, it can be concluded that the chosen protocol is suitable for selection of the cell culture material, and that the most commonly used microchip materials are compatible with HL60 culturing. [source] Large-Scale Synthesis of Water Dispersible Ceria Nanocrystals by a Simple Sol,Gel Process and Their Use as a Chemical Mechanical Planarization SlurryEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2008Taekyung Yu Abstract Ceria nanocrystals with a cube shape were synthesized from the hydrolytic sol,gel reaction of cerium salt in the presence of oleylamine. The overall synthetic process is very simple and readily applicable to the large-scale synthesis of tens of grams of product in a single reaction in air. These ceria nanocrystals are readily dispersible in aqueous media without the addition of any extra dispersing agent. The aqueous dispersion of the ceria nanocrystals was successfully used as a chemical mechanical polishing slurry, and it exhibited high removal selectivity between silicon oxide and silicon nitride at pH 7.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Nanoparticle Arrays on Surfaces Fabricated Using Anodic Alumina Films as Templates,ADVANCED FUNCTIONAL MATERIALS, Issue 5 2003M.S. Sander Abstract High density nanoparticle arrays on surfaces have been created using a template-assisted approach. Templates were produced by evaporating aluminum onto substrates and subsequently anodizing the aluminum to produce nanoporous alumina films. The resulting templates have a narrow distribution of pore sizes tunable from ,,25 to ,,70 nm. To demonstrate the flexibility of this approach for producing nanoparticle arrays on various substrates, templates have been fabricated on silicon oxide, silicon, and gold surfaces. In all cases, a final chemical etching step yielded pores that extended completely through the template to the underlying substrate. Because the templates remain in intimate contact with the substrate throughout processing, they may be used with either vacuum-based or wet chemical deposition methods to direct the deposition of nanoparticles onto the underlying substrates. Here we have produced gold nanodot arrays using evaporation and gold nanorod arrays by electrodeposition. In each case, the diameter and height of the nanoparticles can be controlled using the confining dimensions of the templates, resulting in high density (,,1010,cm,2) arrays of nanoparticles over large areas (>,1 cm2). [source] Precise Structure of Pentacene Monolayers on Amorphous Silicon Oxide and Relation to Charge TransportADVANCED MATERIALS, Issue 22 2009Stefan C. B. Mannsfeld The precise molecular packing in pentacene monolayers on silicon oxide is determined for the first time using a combination of grazing incidence X-ray diffraction (GIXD) and crystallographic refinement calculations. The pentacene molecules are found to adopt a completely tilt-free herringbone motif, the charge-transport properties of which are discussed on the basis of density functional theory calculations. [source] Enhanced Charge Separation by Sieve-Layer Mediation in High-Efficiency Inorganic-Organic Solar CellsADVANCED MATERIALS, Issue 7 2009Chien-Hung Lin The introduction of a thin electronic sieve layer of a material with a wide bandgap, such as lithium fluoride (LiF) or silicon oxide (SiOx), at the inorganic-organic interface of an organic photovoltaic device enhances the charge separation and improves the efficiency by more than an order to a maximum of 6.04%. [source] Fabrication of Highly Ordered Silicon Oxide Dots and Stripes from Block Copolymer Thin Films,ADVANCED MATERIALS, Issue 4 2008S. Park A general route to fabricate highly ordered arrays of nanoscopic silicon oxide dots and stripes (see figure) from block copolymer thin films is described. Poly(styrene- b -4-vinylpyridine) thin films with cylindrical microdomains oriented normal and parallel to the surface were used as templates for the fabrication of nanoscopic silicon oxide, with polydimethylsiloxane as the inorganic precursor. [source] Spin-Coating-Derived Gold-Nanoparticle MemoryJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2010Ching-Chich Leu A metal,oxide,semiconductor (MOS) capacitor embedded with gold nanoparticles (Au NPs) has been successfully fabricated by a spin-coating-derived chemical solution process. The colloidal synthesized Au NPs (,3.5 nm) were self-assembled to 3-aminopropyltrimethoxysilane-modified silicon oxide substrates. With the spin-coating process, Au NPs can be fabricated onto silicon oxide with a high packing density of 1.6 × 1012 cm,2 in a short processing time. The sol,gel-derived HfO2 layer, acting as a control oxide, was also spin coated to construct an Si/SiO2/Au NPs/HfO2 structure. This MOS structure showed good memory effect and retention properties. This study indicates that it is appropriate to utilize the spin-coating process in nanocrystal memory applications. [source] Enhanced performance by inserting ultrathin SiO2 layer in organic light-emitting devicesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2007Lianbin Niu Abstract Improved performance of organic light-emitting devices (OLEDs) has been obtained by insertion of an ultrathin film of silicon oxide (SiO2) at the interface of 8-hydroxyquinoline aluminum (Alq3) and N,N ,-bis(1-naphthyl)- N,N ,-diphenyl-1,1,-biphenyl-4,4,-diamine (NPB) layers. When a 1.0 nm SiO2 film was inserted, for an unoptimized indium,tin oxide (ITO)/NPB/SiO2/Alq3/Al device, the current efficiency was as high as 7.35 cd/A. Compared with conventional devices, a higher efficiency has been achieved. The mechanism of performance enhancement is discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Optimized-geometry ARROW waveguides using TiO2 as anti-resonant layerPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010Daniel O. Carvalho Abstract The simulation, fabrication and characterization of ARROW waveguides using dielectric films deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) and Sputtering techniques, are presented in this work. Amorphous titanium oxide (TiO2) films were used as first cladding layer and silicon oxynitride (SiOxNy) films, as core layer. Furthermore, homemade routines based in two computational methods were used, for numerical simulations: Transfer Matrix Method (TMM) for the determination of the optimum thickness values of the Fabry-Perot layers, and the Finite Difference Method (FDM) for 2D design and determination of the maximum width that allows single-mode operation. The utilization of thermally grown silicon oxide as second anti-resonant layer, along with improvements in the Reactive Ion Etching conditions for the definition of sidewalls of the optical waveguides were responsible for diminishing optical attenuations. Optimization of the waveguide rib height was done both through FDM simulations and experimentally. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Defects and structure of µc-SiOx:H deposited by PECVDPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010Lihong Xiao Abstract Electronic transport and paramagnetic defects detected by Electron Spin Resonance (ESR) in both intrinsic and Microcrystalline silicon n-i-p solar cells prepared with microcrystalline silicon oxide (,c-SiOx:H) n-layerPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3-4 2010Vladimir Smirnov Abstract N-type hydrogenated microcrystalline silicon oxide (,c-SiOx:H) layers were used as window layers in n-side illuminated microcrystalline silicon n,i,p solar cells. Optical, electrical and structural properties of ,c-SiOx:H films were investigated by Photothermal Deflection Spectroscopy, conductivity and Raman scattering measurements. ,c-SiOx:H layers were prepared over a range of carbon dioxide (CO2) flow and film thickness, and the effects on the solar cell performance were investigated. By optimising the ,c-SiOx:H window layer properties, an improved short-circuit current density of 23.4 mA/cm2 is achieved, leading to an efficiency of 8.0% for 1,m thick absorber layer and Ag back contact. The correlation between cell performance and ,c-SiOx:H layer properties is discussed. The results are compared to the performance of solar cells prepared with alternative optimised window layers. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] On dot and out of dot electrical characteristics of silicon oxide nanodots patterned by scanning probe lithographyPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2009Sabar D. Hutagalung Abstract Silicon oxide nanodot arrays were grown on pre-cleaned silicon (100) substrate by scanning probe nanolithography. In this study, a conductive AFM was used to fabricate nanoscale oxide dots in humidity controlled environment. The AFM is equipped with a nanotechnology software package providing the control of tip-sample voltage and tip motion according to pre-designed patterns. The surface topography and size of obtained patterns (diameter and height) were investigated by a noncontact AFM mode. A series of five silicon oxide nanodot array with diameter in the range of 146.05-247.65 nm and height 2.14-4.87 nm had been successfully fabricated. Meanwhile, a contact AFM mode was used to investigate the localized I-V characteristics on the dots and out of dot position. It was found, the on dot characteristics are highly nonohmic due to potential barrier interface between silicon oxide and silicon substrate. However, the out of dot characteristic is linear indicates an ohmic contact between AFM tip and sample. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Multilayer Diffusion Barrier Coatings on Poly(propylene) with Improved Temperature DurabilityPLASMA PROCESSES AND POLYMERS, Issue S1 2009Lutz Körner Abstract The improvement of temperature durability for autoclaving of silicon oxide (SiOx) diffusion barrier coatings on poly(propylene) (PP) by deposition of thin amorphous hydrogenated carbon-nitrogen (a-C:N:H) intermediate layers was investigated. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy revealed terminating amino and nitrile groups responsible for low compressive stress in a-C:N:H. Uniaxial tensile tests showed a higher crack onset strain (COS) for a-C:N:H of 2.7% compared to 0.7% for SiOx. Best temperature durability was achieved by a three-layer coating from a-C:N:H, an intermediate layer deposited by a mixture of N2, C2H2, hexamethyldisiloxane (HMDSO), and a SiOx layer. The oxygen transmission rate (OTR) was only increased from 6 to 22 cm3·m,2·d,1·bar,1 after exposure to 140,°C for 30 min, whereas for single SiOx barrier coatings, severe loss of barrier properties of 1,040 cm3·m,2·d,1·bar,1 was evidenced due to the formation of cracks. [source] SiOx-Based Multilayer Barrier Coatings Produced by a Single PECVD ProcessPLASMA PROCESSES AND POLYMERS, Issue S1 2009Alessandro Patelli Abstract Multilayer organic/inorganic gas barrier coatings on plastics are needed for high performance demanding applications from OLEDs to packaging. In order to simplify the multilayer deposition process, we developed a single step vacuum process where silicon oxide-based PECVD multilayers are obtained by the modulation of the hexamethyldisiloxane (HMDSO) precursor inlet and interfaces are controlled by pumping speed. In this way, depending on O2/HMDSO ratio, ,ceramic' or ,polymeric' layers are deposited, with nanometre control of thickness of layers and interfaces. Permeability behaviour of the multilayer structures obtained is described as a function of the number of layers and their thickness. [source] Site-selective studies of erbium ion defects in thermally grown silicon oxidesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2007Z. Fleischman Abstract Using the site-selective technique of combined excitation emission spectroscopy (CEES), we have studied a variety of Er-doped silicon oxide layers and silicon-rich oxide (SRO) layers which contain silicon nanocrystals. With this technique we identi.ed Er cluster defect sites which are created during thermal annealing and which dominate at high Er concentrations. We investigate the role that Si nanocrystals play in the relative abundance of these cluster sites. In attempts to reduce this clustering effect, we observed mixed results by modifying the growth procedure such that Er is already present in the silicon during oxide growth. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]
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