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Abstract: Polycrystalline In x Ga1−x N thin films were prepared by mixed source modified activated reactive evaporation (MARE) technique. The films were deposited at room temperature on glass substrates without any buffer layer. All the films crystallize in the hexagonal wurtzite structure. The indium concentration calculated from XRD peak shift using Vegard''s law was found to be varying from 2% to 92%. The band gap varies from 1.72eV to 3.2eV for different indium compositions. The indium rich films have higher refractive indices as compared to the gallium rich films. The near infra-red absorption decreases with gallium incorporation into InN lattice which is mainly due to decrease in the free carrier concentration in the alloy system. This fact is further supported from Hall effect measurements. MARE turns out to be a promising technique to grow In x Ga1−x N films over the entire composition range at room temperature. [Copyright &y& Elsevier]

Abstract: We report the effect of rf power on the structural, optical and electrical properties of InN films grown by modified activated reactive evaporation. In this technique, the substrates were kept on the cathode instead of ground electrode. The films grown at higher rf power shows preferential c-axis orientations for both silicon and glass substrates. The films prepared at 100W show best structural, electrical and optical properties. The c-axis lattice constant was found to decrease with increase in rf power which can be attributed to reduction in excess nitrogen in the films. The band gap decreases with increase in rf power due to Moss–Burstein shift. The decrease in carrier concentration and optical band gap with increase in rf power can also be related to excess nitrogen in the film. The Raman spectra shows a red shift in the A1(LO) and E2 (high) mode from the reported value. The possible origin of the present large band gap is due to Moss–Burstein shift. The new film growth method opens opportunities for integrating novel substrate materials with group III nitride technologies. [Copyright &y& Elsevier]