Cathodoluminescence Studies of InGaN/GaN Multiple Quantum Well Structure Grown by Metal Organic Chemical Vapor Deposition

Abstract

Scanning Electron Microscope (SEM) - Cathodoluminescence (CL) system is applied to blue emission InGaN/GaN Multiple Quantum Well (MQW) structure grown by Metal Organic Chemical Vapor Deposition (MOCVD) to study the luminescence properties of v-pit features and surface compositional variations. Emission from MQW layer and bulk n-GaN layer beneath are captured at various electron beam voltages and show that the luminescence efficiency of latter grown MQW layer may be related to that of the former grown n-GaN layer. Emission intensity variations are observed at v-pit free areas in the CL images, and it is observed that areas with higher emission intensity always show a red shift in emission wavelength. It may therefore indicate that high resolution CL system is able to image the indium inhomogeneities formed during the epitaxial growth process in nanoscale.