Carrier dynamics studies of III-nitride materials using photo-acoustic and photoluminescence measurements

Abstract

Internal quantum efficiency (IQE) of radiative recombination for photo-excited carriers in compound semiconductor materials is usually estimated from temperature dependence of photoluminescence (PL) intensity by assuming that the IQE at cryogenic temperature is unity. III-nitride semiconductors, however, usually have large defect-density, and the assumption is not necessarily valid. In this study, we developed a new method to estimate accurate IQE values by simultaneous PL and photo-acoustic (PA) measurements, and demonstratively evaluated the IQE values for an InGaN quantum-well sample. The results show that the conventional method cannot give accurate IQE values, and that our method is a promising way for accurate estimation of absolute IQE values, which could lead to the accurate estimation of radiative and nonradiative recombination lifetimes in carrier dynamics studies.