Evaluation of internal quantum efficiency and stimulated emission characteristics in AlGaN-based multiple quantum wells

Based on our recent studies, we review our proposed experimental method for evaluating internal quantum efficiency, which is a critical parameter for semiconductor light-emitting device performance. We validated our evaluation method by comparing the results of the efficiency curve analysis using an exciton rate equation model with the results of radiative and nonradiative recombination dynamics obtained by time-resolved photoluminescence spectroscopy. We also review the characteristics of the stimulated emission observed from optically pumped Al x Ga 1− x N-based multiple quantum wells. The most important finding was the contribution of excitons to optical gain formation. The excitonic gain is expected to decrease the threshold carrier density for stimulated emission and lead to higher performance of semiconductor laser diodes.