Polarity dependence of In-rich InGaN ternary alloys and InN/InGaN MQWs

摘要

In-rich InGaN films (X_(In) > 0.5) and InN/InGaN multi-quantum wells were grown on Ga- and N-polarity GaN templates by radio-frequency plasma-assisted molecular beam epitaxy. The In-polarity InGaN films grown at 450°C showed superior crystalline quality and smoother surface morphology compared to the N-polarity samples, which were grown at 500～550°C. By using the In-polarity In_(0.7)Ga_(0.3)N as a barrier layer, the InN/InGaN multi-quantum wells were successfully fabricated on the III-element polarity GaN templates at 450°C. Fine periodic structures and strong photoluminescence emission around optical communication wavelength were obtained from the In-polarity MQWs. These results indicate that high quality InGaN films and the InN/InGaN MQWs can be obtained in the In-polarity growth regime in spite of its lower growth temperature.