In this work, using Density Functional, Hartree-Fock and Extended H uckel Theories together with the supercell and cluster model approaches, we present our preliminary results for the simulation of the adsorption of Si and C atoms over the (111) SiC surfaces as well as the torsion of SiC molecules at that surfaces. Our results shown that, before and after the adsorption, the cubic structure ar...

We have explored the properties of SiC-based epitaxial graphene grown in a cold wall UHV chamber. The effects of the SiC surface orientation and silicon loss rate were investigated by comparing the characteristics of each formed graphene. Graphene was grown by thermal decomposition on both the silicon (0001) and carbon (000-1) faces of on-axis semi-insulating 6H-SiC with a "face-down" and "face...

4H-SiC is a wide-bandgap semiconductor with potential applications in power devices. The lack of a liquid phase in SiC hinders conventional crystal growth from the melt; consequently, SiC wafers still have low quality and are nearly 100 times more expensive than Si wafers. To take advantage of the solution growth for improving the quality and reducing the cost of SiC, Ni addition to Si-Ti flux ...

SiC is a candidate material for microand nano-electromechanical systems (MEMS and NEMS). In order to understand the impact that the growth rate has on the residual stress of CVDgrown 3C-SiC hetero-epitaxial films on Si substrates, growth experiments were performed and the resulting stress was evaluated. The film thickness was held constant at ~2.5 μm independent of the growth rate so as to allo...

This study investigated the contamination of abraded Ti surfaces. Using a polishing machine, specimens were abraded with waterproof SiC grit papers under water cooling. The abraded surfaces were examined using element analysis, X-ray diffraction, and hardness tests. Contaminant deposits with dimensions reaching about 30 microns were observed throughout the surface. In these deposits, Ti was app...

Thermal reactions of Co(200 A) /Si0,76Ge0,24( 1500 A) /Si and Co(200 A) /Si0,54Ge0,46( 1000 A) /Si systems in a vacuum of l2 X 10m6 Torr were studied. At temperatures above 200°C Ge segregation appeared even though no silicides and/or germanosilicides were formed. At a temperature of 225-550°C Co(Si, -vGe,) was formed, in which the Ge concentration was deficient. The formation temperatures of C...

Composites based on two aluminium alloys (A536 and 6061) reinforced with 10% or 20% volume fraction of SiC particles were produced by gravity casting and a novel two-step mixing method was applied successfully to improve the wettability and distribution of the particles. The SiC particles were observed to be located predominantly in the interdendrit ic regions, and a thermal lag model is propos...

X-ray absorption spectroscopy on the Si k-edge was performed on a-Sic (6H) to monitor the evolution of the local structure around the Si atoms after ion bombardment. The samples were irradiated by 50 keV Na ions at fluences of 10" 10" ions/cma at a temperature of 80 K. EXAFS analysis clearly reveals that the hetero-atomic short range order of the crystalline matrix is almost completely conserve...

We report a simple, handy and affordable optical approach for precise number-oflayers determination of graphene on SiC based on monitoring the power of the laser beam reflected from the sample (reflectance mapping) in a slightly modified micro-Raman setup. Reflectance mapping is compatible with simultaneous Raman mapping. We find experimentally that the reflectance of graphene on SiC normalized...

Presolar SiC grains of the types mainstream, Y, and Z are believed to have formed in thermally pulsing asymptotic giant branch stars with a range of metallicity: mainstream grains in stars of close-to-solar metallicity, Y grains in stars of around half-solar metallicty, and Z grains in stars of around one-third solar metallicity. From their Si and Ti isotopic ratios, it is possible to obtain in...