Influence of high electron concentration on band gap and effective electron mass of InN

Effects of high electron concentration on the band gap energy of InN films having different layer thicknesses as 600 and 800 nm are investigated experimentally and theoretically. Electron concentrations of the samples are obtained through the Hall measurements accomplished between 77K and room temperature. Optical characterization of the samples is carried out using the photoluminescence (PL) measurements and the observed PL spectra are explained considering the high electron concentration related effects, i.e. Burstein-Moss shift, band renormalization and band tailing in non-parabolic k.p model. Extracted PL results indicate that the samples have approximately 0.685 eV band gap energy at 77 K. Effective mass of the carriers, which is calculated as 0.097m(0) for electron concentration of similar to 10(19) cm(-3), are also observed to be influenced by the high carrier concentration. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei