Abstract

In this study, we investigate In composition and the carrier density dependences of radiative and nonradiative recombination lifetimes for a series of c-plane InGaN quantum well (QW) samples with different emission wavelengths (450 nm to 620 nm). The two lifetimes can be separately evaluated using photoluminescence (PL) decay time, obtained by time-resolved PL measurement, combined with the value of internal quantum efficiency (IQE) obtained by simultaneous photoacoustic and PL measurements. It is found that the decrease in IQE with increasing In composition is caused by the reduction in radiative recombination lifetime, not by the enhancement of nonradiative lifetime, which shows little dependence on In composition. In addition, it is found that the carrier density dependence of IQE is also mainly determined by the change in radiative recombination lifetime. These findings will lead to a comprehensive understanding of carrier dynamics in InGaN-QW optical devices.