CW operation of InGaN MQW laser diodes

Major developments in wide-gap III-V nitride semiconductors have recently led to the commercial production of high-brightness blue/green light-emitting diodes (LEDs) and to the demonstration of room-temperature (RT) bluish-purple laser light emission in InGaN/GaN/AlGaN-based heterostructures under pulsed currents and continuous-wave (CW) operation. The radiative recombination of the spontaneous and stimulated emission of the InGaN MQW LEDs and LDs was attributed to excitons (or carriers) localized at deep traps (250 meV) which originated from the In-rich region in the InGaN wells acting as quantum dots. The fundamental properties of semiconductor lasers are specified by the optical gain. Recently, RT CW operation of the InGaN MQW LDs with a lifetime of 35 hours has been achieved. Here, we report the optical gain and the emission characteristics of InGaN single-quantum-well (SQW) LEDs and RT CW-operated MQW LDs.