Effect of high temperature and interface treatments on photoluminescence from InGaN/GaN multiple quantum wells with green light emissions

InGaN/GaN multiple quantum wells (MQWs) with emission peaks in the green light region were grown by metalorganic chemical vapor deposition. Photoluminescence (PL) measurements on these samples showed extra peaks in the spectrum beside the green emission due to reactor temperature ramping up to 1000 °C after the MQWs growth. It was found that growth interruption at the upper interface of MQWs combining with interface treatment by H2 flow could eliminate these extra peaks. Our analysis of the PL spectra suggested that these extra emission peaks originate due to the occurrence of In segregation in the upper part of the quantum wells induced by partial strain relaxation in the processes of high temperature treatment, and the interface treatment with H2 flow can suppress this phase separation phenomenon.