Advantages of Ultrathin AlN/GaN/AlN Quantum Wells for Excitonic Population Distribution and Transition Features Studied by Phononic–Excitonic–Radiative Model

Abstract

Excitons are expected to be a high‐efficiency emission source in UV light‐emitting devices. However, the damping of the excitonic laser oscillation has been reported under conditions where the excitonic states are expected to be populated in the conventional theory. In order to understand the exciton dynamics under the thermal nonequilibrium state, a theoretical model including various energy species in semiconductors such as electrons, phonons, and photons is required. Herein, a 2D phononic–excitonic–radiative model is constructed to analyze the exciton dynamics in a 2D system. 2D excitons with four principal quantum number states and the continuum in the lowest energy level of the AlN/GaN/AlN quantum wells are considered. It is found that the 2D phonon significantly augments the excitation transition rate. When the high recombination rate corresponding to stimulated emission is considered, the exciton binding energy of 108 meV is not enough to reduce the population in the high‐order discreet states and the continuum states, while the binding energy of 215 meV corresponding to the one monolayer GaN has an advantage of reducing these populations. The analysis of population flux has an advantage in discussing the increase in the kinetic energy transfer to the 1S exciton.