Growth of IIIN microLEDS on Si(100) substrates would enable direct integration with Si based CMOS. An oxide buffer is used to translate the crystal symmetry so that GaN(0001) can be grown on Si(100) in a wurtzite form. InGaN quantum dots (QDs) are presented as a novel solution to obtaining a red LED from the III-N material system. An engineered bottom contact is demonstrated by the addition of an epitaxial metal layer below the QDs.
Plasma spraying technique was used for deposition of Al and Ni-Al coatings with special electrochemical characteristics. Influence of the plasma spraying process on characteristics of plasma stream and properties of the deposited coatings was investigated. Temperature field in the plasma torch, dependence of temperature of the probe placed in the plasma stream on the gas flux, pressure in the deposition chamber and arc discharge output power were measured experimentally. Surface morphology of th3 coatings by optical microscope and scanning electron microscope was investigated. It was found high dependence of the morphology on composition of the plasma gas. X-ray technique for investigation of chemical composition of the coatings was used. It was found that inter-diffusion of nickel and aluminum during deposition of the coatings takes part. This phenomenon influences chemical composition of the surface and electro-chemical characteristics of the coatings.
Thermal annealing of plasma sprayed Ni/Al coatings used as the catalyst was investigated. The coatings were plasma sprayed on Cu substrate at low vacuum conditions (approximately 1 Pa) and were heated at temperatures of 600 degree(s)C and 800 degree(s)C in Ar atmosphere for 5 hours. Scanning electron microscopy and X-ray diffraction were used to study influence of annealing on the morphology and phase transformation in the Ni/Al coatings. A change of morphology of the coatings to smoother and less porous during thermal treatment was observed. Grain size number changes from n equals 5.52 for annealed coatings to n equals 5.37 and n equals 5.26 for coatings annealed at 600 degree(s)C and 800 degree(s)C, respectively. At the same time phase transformation with appearance of new alloys took place. These changes greatly influence other properties of the Ni/Al coatings.
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