Development of AlGaN-based deep ultraviolet light-emitting diodes and laser diodes

Recently, our group has demonstrated several methods to improve the performance of deep ultraviolet (DUV) LEDs and LDs. A high-quality and crack-free AlN template has been achieved by inserting multiple middle-temperature AlN layers with modulated source flow. Using silicon-doped AlGaN MQWs, the internal quantum efficiency (IQE) has been increased by 41% due to the improvement of crystal and interface quality. An easy-facilitative Al reflector technique has been also proposed to enhance the light extraction efficiency (LEE). We obtained light output power (LOP) of 6.31 mW for the 280-nm LED at 100 mA, and realized optical pumping stimulated emission at 288 nm.