Temperature-dependent inhomogeneous optical behavior of AlInGaN quaternary alloys

The temperature-dependent anomalous optical properties of AlInGaN quaternary alloys have been studied using Monte Carlo simulation of phonon-assisted exciton hopping. The simulation results agreed well with the experimental photoluminescence linewidths and the peak energy positions while considering the additional inhomogeneous broadening with band potential fluctuation and the phonon-induced radiative lifetime of the exciton. The incorporation of band-gap shrinkage into the conventional Monte Carlo simulation shows a good fit for the photoluminescence peak energy positions in AlInGaN quaternary alloys with temperature-induced experimental unusual behavior (redshift-blueshift-redshift). The W-shaped temperature-dependent inhomogeneities are observed for the PL linewidths. The temperature-induced S-shaped photoluminescence band peaks and W-shaped linewidth have been attributed to the change of exciton dynamics due to the indium aggregated potentials and the exciton localization effects. These results could be important to understanding the realistic optical properties of AlInGaN quaternary alloy-based electronic and optoelectronic devices.