Cathodoluminescence investigations of interfaces in InGaN/GaN/sapphire structures

Scanning electron microscopy and cathodoluminescence (CL) in spot and depth -profiling. modes were used to evaluate the in-plane and in-depth uniformit y of light emission from InGaN/GaN quantum well (QW) structures. The struct ures were grown by MOCVD on sapphire with a low-temperature (LT) GaN buffer . Depth-profiling CL investigations were used to identify the observed CL e missions, which show a complicated in-depth evolution. The influence of a L T GaN buffer on the structural and optical properties of the GaN/sapphire i nterface is discussed.