Epitaxial growth of low temperature GaN using metal migration enhanced epitaxy for high-quality InGaN/GaN heterojunctions

An effective method for high-quality molecular beam epitaxy growth of InGaN/GaN multiple quantum wells is demonstrated by inserting an ultrathin low temperature GaN (LT-GaN) interlayer between InGaN well and conventional high temperature GaN (HT-GaN) barrier layers. The LT-GaN interlayer is fabricated using metal migration enhanced epitaxy at the same growth temperature for InGaN. A smooth LT-GaN surface with a low defect density is obtained and indium decomposition is not observed. Large emission blueshift is significantly suppressed and narrow linewidth photoluminescence emission is achieved. The improved optical properties of the InGaN/GaN MQWs with LT-GaN interlayers are due to reduced compositional fluctuation and improved interface roughness.