Stimulated emission characteristics of InGaN/GaN multiple quantum wells: Excitation length and excitation density dependence

Optically pumped stimulated emission (SE) from InGaN/GaN multiple quantum wells (MQWs) grown by metalorganic chemical vapor deposition has been systematically studied as a function of excitation length (L-exc). Two distinct SE peaks were observed from these structures: one that originates at 425 nm at 10 K (430 nm at 300 K) and another that originates at 433 nm at 10 K (438 nm at 300 K). The SE threshold for the high-energy peak was observed to always be lower than that of the low-energy peak, but the difference was found to decrease greatly with increasing L-exc. A detailed study of the emission intensity of these two SE peaks as a function of excitation density shows that the two peaks compete for gain in the MQW active region. (C) 1998 American Institute of Physics. [S0003-6951(98)00551-8].