Time-resolved photoluminescence measurements of InGaN light-emitting diodes

Abstract

We have used time-resolved photoluminescence (PL) to examine light-emitting diodes made of InGaN/GaN multiple quantum wells (MQWs) before the final stages of processing. The time-resolved photoluminescence from a dim MQW was quenched by nonradiative recombination centers. The PL kinetics from a bright MQW were not single exponential but stretched exponential, with the stretch parameter β=0.59±0.05. The emission lifetime varied with energy, within error β was independent of the emission energy. the stretched exponential kinetics are consistent with significant disorder in the material. We attribute the disorder to spatial fluctuations of the local indium concentration.