Evidence of Carrier Localization in AlGaN/GaN-Based UV Multiple Quantum Wells with Opposite Polarity Domains Provided by Nanoscale Imaging

Abstract

AlGaN-based multiple quantum wells (MQWs) incorporating opposite polarity domains are grown by metal–organic chemical vapor deposition (MOCVD). A direct demonstration of the carrier localization effect is provided by a combination analysis of space-resolved luminescence peak position and Ga/Al composition distribution. Furthermore, through Raman spectroscopy, it is found that compressive strain plays a key role in improving the optical properties of UV-MQWs despite the inferior crystalline quality in the N-polar domains. This suggests that incorporating sub-micrometer-scale polarity domains in the MQWs is promising for the development of efficient UV emitters.