Hot-phonon effect on intersubband absorption in GaN/AlGaN quantum well structures

In this work, we demonstrate the direct modeling of hot-phonon effect on the intersubband optical absorption. The numerical method is based on the simulation of optical pumping process in a GaN/AlGaN quantum well structure and temporal sampling of intersubband absorptions at various delay times. We find that the hot-phonon can significantly influence the absorption shapes when the quantum well is doped with higher impurity density. The change of optical absorption detuning is found originating from the enhanced optical phonon absorption scatterings. On the other hand, our results show that the broadening of absorption shapes results from the stronger intersubband optical phonon scatterings due to the hot-phonon effect. Our findings suggest that the hot-phonon effect should be included in the study of intersubband absorptions in GaN/AlGaN quantum well systems with higher doping density.