Semipolar GaN grown on m-plane sapphire using MOVPE

Abstract

We have investigated the MOVPE growth of semipolar gallium nitride (GaN) films on (1010) m-plane sapphire substrates. Specular GaN films with a RMS roughness (10x10 μm2) of 15.2 nm were obtained and an arrowhead like structure aligned along [2113] is prevailing. The orientation relationship was determined by XRD and yielded (2112)GaN ∥ (1010) sapphire and [2113]GaN ∥ [0001]sapphire as well as [2113]GaN ∥ [0001]sapphire. PL spectra exhibited near band edge emission accompanied by a strong basal plane stacking fault emission. In addition lower energy peaks attributed to prismatic plane stacking faults and donor acceptor pair emission appeared in the spectrum. With similar growth conditions also (1013) GaN films on m-plane sapphire were obtained. In the later case we found that the layer was twinned, crystallites with different c-axis orientation were present. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.