Time-resolved photoluminescence measurements of InGaN light-emitting diodes

We have used time-resolved photoluminescence (PL) to examine light-emitting diodes made of InGaN/GaN multiple quantum wells (MQWs) before the final st ages of processing. The time-resolved photoluminescence from a dim MQW was quenched by nonradiative recombination centers. The PL kinetics from a brig ht MQW were not single exponential but stretched exponential, with the stre tch parameter beta = 0.59 +/- 0.05. The emission lifetime varied with energ y, within error beta was independent of the emission energy. The stretched exponential kinetics are consistent with significant disorder in the materi al. We attribute the disorder to spatial fluctuations of the local indium c oncentration. (C) 1998 American Institute of Physics. [S00036951(98)02450-4 ].