Analysis of efficiency curves in near-UV, blue, and green-emitting InGaN-based multiple quantum wells using rate equations of exciton recombination

Abstract

The internal quantum efficiency (IQE) of near-UV, blue, and green-emitting InGaN-based multiple quantum wells was evaluated as functions of excitation power density and temperature using photoluminescence spectroscopy. The IQE curves under weak excitation densities were analyzed using a rate equation model based on the radiative and nonradiative recombination of excitons. The analysis clarified that the initial increase in the estimated IQE could be explained by the filling of nonradiative recombination centers. Moreover, the analysis elucidated that the nonradiative recombination process of excitons was independent of the emission wavelength and that the radiative recombination rate of excitons was strongly affected by the exciton localization and depended on the emission wavelength. Furthermore, the analysis suggested that the maximum IQE reached was 100% in all the samples at a low temperature.