Résumé
We have investigated the heteroepitaxy of indium nitride (InN) directly grown on nitridated sapphire substrates having different orientations. Growths were performed on C, A, M and R-plane oriented sapphire in order to analyse the substrate orientation effect on the structural, optical and electronic properties of as-grown InN. Atomic force microscopy imaging on the InN epilayers revealed different surface morphologies with crystallites well organized along a crystalline orientation of the layer. We have studied the structural anisotropy observed in these layers analysing high-resolution X-ray diffraction rocking curve experiments as a function of the in-plane beam orientation. A-plane oriented InN grown on R-plane sapphire substrate shows a polarized photoluminescence anisotropy, with an anisotropy percentage of about 33%. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim