Scanning near-field microscopy of carrier lifetimes in m-plane InGaN quantum wells

Abstract

Time-resolved scanning near-field photoluminescence (PL) spectroscopy was applied to map carrier lifetimes in wide m-plane InGaN/GaN quantum wells grown on on-axis and miscut substrates. Both radiative and nonradiative lifetimes were found to be spatially nonuniform. Lifetime variations were smaller for quantum wells grown on miscut, as compared to on-axis substrates. Correlation with surface topography showed that largest deviations of recombination times occur at +c planes of pyramidal hillocks of the on-axis sample. Observed correlation between radiative lifetimes and PL peak wavelength was assigned to a partial electron localization.