Simultaneous microscopic PA/PL line-scan measurements in InGaN-QWs on a stripe-core GaN Substrate

Abstract

We have conducted simultaneous photoacoustic (PA) and photoluminescence (PL) measurements to accurately estimate the internal quantum efficiency (IQE). The method detects light from radiative recombination through PL measurement and heat from non-radiative recombination through PA measurement. In this study, we have applied the method to an InGaN-QW sample on a “stripe-core” GaN substrate in which the dislocation density periodically changes. Considering that photo-excited carriers recombine either radiatively or non-radiatively, the heat generation will increase in the defective region where emission efficiency is weak. In the line-scan measurement, the position-dependent complementary relationship between the PA and PL intensity is clearly observed.