Carrier localization and defect-insensitive optical behaviors of ultraviolet multiple quantum wells grown on patterned AlN nucleation layer

Abstract

In this work, we report a significantly boosted defect-insensitive ultraviolet emission from InGaN/GaN multiple quantum wells (MQWs) grown on patterned AlN nucleation layer (NL) compared to samples grown on uniform NL. Carrier localization is clearly illustrated for MQWs grown on patterned AlN NL as evidenced by an S-shape profile from temperature-dependent photoluminescence characterization. The underlying mechanism for the carrier localization is demonstrated to correlate with partial relaxation of compressive strains inside epitaxial thin films. This work illustrates that carrier localization can be achieved in MQWs with very low indium content by the adoption of patterned NL during growth, and provides a promising route towards the realization of high-efficiency ultraviolet emitter.