Investigation of the Indium migration mechanism in the growth of InGaN quantum wells by MOCVD

Improvement of InGaN quantum wells (QWs) with high In content is crucial for realizing well GaN-based optoelectronic devices, such as laser diodes (LDs) and light-emitting diodes (LEDs). In this paper, the migration mechanism of In atoms and its impact on the luminescence properties of green QWs are studied, and the material and optical quality of high-In-content InGaN QWs can be improved by increasing the Indium migration ability through low-pressure growth method. The experimental results show that the In incorporation into InGaN QWs decreases while the luminescence property increases with the decrease of growth pressure when the growth process is under the surface-reaction-controlled mode. The analysis of the evolution behavior of InGaN/GaN interfaces through TEM measurements reveals that the migration ability of In atoms is a key factor affecting the continuity of InGaN QWs and the formation of In aggregation. Further temperature-dependent photoluminescence (TDPL) analysis and theoretical investigation on the LSE model confirm that the improvement in the luminescence efficiency of QWs is attributed to the enhancement of interface quality and the weakening of localized states. These results provide a new technical direction for the development of high-performance LEDs and LDs.