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Abstract: In the present work, we report the growth of wurtzite InN epilayers on GaN/Si (111) substrate by plasma-assisted molecular beam epitaxy (PAMBE). The growth parameters such as indium flux, substrate temperature and RF power affect the crystallographic and morphological properties of InN layers, which were evaluated using high resolution X-ray diffraction (HRXRD) analysis and atomic force microscopy (AFM). It is found that excess indium (In) concentrations and surface roughness were increased with increase in In flux and growth temperature. The intensity of HRXRD (0002) peak, corresponding to c-axis orientation has been increased and full width at half maxima (FWHM) has decreased with increase in RF power. It was found that highly c-axis oriented InN epilayers can be grown at 450°C growth temperature, 450W RF power and 1.30×10−7 mbar In beam equivalent pressure (BEP). The energy gap of InN layers grown by optimizing growth conditions was determined by photoluminescence and optical absorption measurement. [Copyright &y& Elsevier]

Abstract: The effect of substrate bias on the structural, morphological, electrical and mechanical properties of hydrogenated amorphous carbon films having embedded nanocrystallites deposited by cathodic jet carbon arc technique has been investigated. X-ray diffraction exhibits predominantly an amorphous nature of the film with nanocrystallites of diamond embedded in the amorphous carbon matrix. High resolution transmission electron microscope investigations reveal largely a uniform amorphous structure. However, an ultra fine microstructure with the average grain size between 8 and 25nm was constituting the entire film with the diffused grain boundaries between the grains. Majority of the individual grains are single crystallite with the preferred inter planar spacing of about 0.213nm and 0.208nm corresponding to the diamond planes of 102 and 103, respectively. All the evaluated parameters were seen to depend strongly on the negative substrate bias and exhibit maxima or minima in the properties of the films deposited at −60V substrate bias. [Copyright &y& Elsevier]