Suppression the formation of V-pits in InGaN/GaN multi-quantum well growth and its effect on the performance of GaN based laser diodes

The mechanism for the formation of V-pits in InGaN/GaN multi-quantum well (MQW) growth and its effect on the performance of GaN based laser diodes (LDs) are investigated in detail. It is observed that the V-pits in InGaN/GaN MQWs begin at the GaN barrier layer rather than InGaN well layer due to the low atomic migration ability of Ga atoms at low growth temperature. In addition, it is found that the formation of V-pits can be suppressed remarkably when a small amount of In atoms is introduced during GaN barrier layer growth. This may be attributed to the decrease of the potential barrier for atom migration around the dislocation region. In this way, the thermal stability of InGaN/(In)GaN MQWs is enhanced. Therefore, the threshold current decreases abruptly when using InGaN/InGaN MQWs instead of InGaN/GaN MQWs. (C) 2020 Elsevier B.V. All rights reserved.