Search results for "Epitaxy"
showing 10 items of 287 documents
Low Temperature Growth of High Purity, Low Resistivity Copper Films by Atomic Layer Deposition
2011
The atomic layer deposition of copper metal thin films was achieved using a three precursor sequence entailing Cu(OCHMeCH2NMe2)2, formic acid, and hydrazine. A constant growth rate of 0.47−0.50 A/cycle was observed at growth temperatures between 100 and 170 °C. The resulting films are high purity and have low resistivities.
Atomic layer deposition of ferroelectric LiNbO3
2013
The ferroelectric and electro-optical properties of LiNbO3 make it an important material for current and future applications. It has also been suggested as a possible lead-free replacement for present PZT-devices. The atomic layer deposition (ALD) technique offers controlled deposition of films at an industrial scale and thus becomes an interesting tool for growth of LiNbO3. We here report on ALD deposition of LiNbO3 using lithium silylamide and niobium ethoxide as precursors, thereby providing good control of cation stoichiometry and films with low impurity levels of silicon. The deposited films are shown to be ferroelectric and their crystalline orientations can be guided by the choice of…
Colloidal lithography and Metal-Organic Chemical Vapor Deposition process integration to fabricate ZnO nanohole arrays
2010
A complete set up of optimal process conditions for an effective colloidal lithography/catalyst assisted MOCVD process integration is presented. It mainly focuses on the determination of the deposition temperature threshold for ZnO Metal-Organic Chemical Vapour Deposition (MOCVD) as well as the concentration of metal-organic silver (Ag) catalyst. Indeed, the optimization of such process parameters allows to tailor the ZnO film morphology in order to make the colloidal lithography/catalyst assisted MOCVD approach a valuable bottom up method to fabricate bi-dimensional ordered ZnO nanohole arrays. (C) 2010 Elsevier B.V. All rights reserved.
Effects of Metal-Organic Chemical Vapour Deposition grown seed layer on the fabrication of well aligned ZnO nanorods by Chemical Bath Deposition
2011
Well aligned, long and uniform ZnO nanorods have been reproducibly fabricated adopting a two-steps Metal-Organic Chemical Vapour Deposition (MOCVD) and Chemical Bath Deposition (CBD) fabrication approaches. Thin (<100 nm) ZnO buffer layers have been seeded on silicon substrates by MOCVD and ZnO layers have been subsequently grown, in form of well textured nanorods, using CBD. It has been found that the structure and thickness of the seed layer strongly influence the final morphology and the crystal texturing of ZnO nanorods as well as the CBD growth rate. There is, in addition, a strong correlation between morphologies of CBD grown ZnO nanorods and those of the seed layer underneath. Thus, …
Structural characterization of original 3D gallium structures grown by LP‐MOCVD
2004
This study is concerned with the growth and characterization of metallic gallium 3D structures, obtained with a single growth step, by the LP-MOCVD technique on various substrates. Commercial organo-metallic is used as gallium precursor and nitrogen as carrier gas. The growth temperature and the reactor pressure are ranking between 500 and 700 °C, and between 150 and 700 torr, respectively. Depending on the elaboration conditions, different 3D structures are obtained such as droplets, cauliflowers, aggregates or thin stems, with micrometer sizes. The morphology, substrate surface density and thermal stability are studied by optical and scanning electron microscopy. At last, X-ray microanaly…
Single quantum dot emission at telecom wavelengths from metamorphic InAs/InGaAs nanostructures grown on GaAs substrates
2011
3 figuras, 3 páginas.
Electroburning of few-layer graphene flakes, epitaxial graphene, and turbostratic graphene discs in air and under vacuum
2015
Graphene-based electrodes are very promising for molecular electronics and spintronics. Here we report a systematic characterization of the electroburning (EB) process, leading to the formation of nanometer-spaced gaps, on different types of few-layer graphene (namely mechanically exfoliated graphene on SiO2, graphene epitaxially grown on the C-face of SiC and turbostratic graphene discs deposited on SiO2) under air and vacuum conditions. The EB process is found to depend on both the graphene type and on the ambient conditions. For the mechanically exfoliated graphene, performing EB under vacuum leads to a higher yield of nanometer-gap formation than working in air. Conversely, for graphene…
Molybdenum thin film growth on a TiO2 (1 1 0) substrate.
2009
International audience; We report a first principles study on the structure and energetics of thin films of molybdenum on a (1 1 0) surface of rutile TiO2. Mo films with 1 × 1 epitaxy in the coverage range between 0.5 and 2 monolayer are investigated. The most stable structures are those which maximize the number of Mo–Mo bonds. This leads to two-dimensional structures with zigzag Mo–Mo coordination for 1 monolayer coverage and three-dimensional structures with approximately body-centered cubic coordination for higher coverage. For a coverage up to 1.5 monolayers, the interface Mo atoms preferentially occupy the so-called upper hollow adsorption site with three Mo–O bonds
Morphology of ZnO grown by MOCVD on sapphire substrates
2004
A quantitative roughness and microstructural analysis of ZnO grown on sapphire by atmospheric metalorganic chemical vapor deposition (MOCVD) is presented. In order to investigate the influence of the substrate on the morphology, different sapphire orientations have been employed. Scanning force microscopy data have been analyzed for a variety of thicknesses to elucidate, if possible, the growth mechanisms involved in the growth process. Our study reveals significant differences between morphologies depending on whether the substrate surface exhibits steps (misoriented a-, c- and r-planes) or not (m-plane); however, no major differences on the calculated roughness coefficients have been foun…
Vapor phase epitaxy of Hg1−xCdxI2 layers on CdTe substrates
1997
Vapor phase epitaxy (VPE) has been studied to grow Hg1 − xCdxI2 epitaxial layers on CdTe bulk substrates. The effect of the VPE growth conditions on the morphology, composition and crystalline quality of Hg1 − xCdxI2CdTe heterostructures has been investigated. It has been shown that 10–30 μm thick Hg1 − xCdxI2 layers can be successfully grown using an α-HgI2 polycrystalline source under isothermal conditions at a temperature in the range 170–240°C for the time period 20–50 h. Interestingly, the VPE growth was found to consist of two successiv stages with different kinetics as follows: (1) a fast growth of an HgI2 platelet layer on the CdTe substrate surface and (2) a slow growth of an Hg1 −…