Cathodoluminescence characterization of [112̄0]-oriented InGaN/GaN thin films grown on r-plane sapphire substrates by metalorganic vapor-phase epitaxy

Abstract

We report the cathodoluminescence (CL) characterization of nonpolar [112̄ 20]-oriented InGaN/GaN thin films grown on r-plane sapphire substrates by atmospheric metalorganic vapor-phase epitaxy. The epitaxial GaN films grown on r-plane sapphire substrates frequently show facet surface morphology. The CL peak wavelength and local indium composition of InGaN grown on them were gradually varied with the probed position from the facet summit to valley. In a-plane InGaN, the facet summit was In-rich area while the valley was In-poor area. This is due to the material transport issue during epitaxial growth. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.