Mechanism of trench defect formation in InGaN/GaN single quantum well grown on single-crystal GaN substrate

Abstract

The light emission property of InGaN quantum wells is seriously deteriorated in the red wavelength with high indium concentration, which is accompanied by structural defects called trench defects. However, the formation mechanism of trench defects has not been fully understood. In this study, we reveal the origin of this defect by utilizing the simplest system, one consisting of a single InGaN quantum well on a single-crystal GaN substrate to extract the effect solely from indium addition. Trench defects are found to be associated with a stacking fault in the cap GaN layer right above InGaN and with an excess layer in InGaN.