Ionized Acceptor Bound Exciton States in Wurtzite GaN/AlxGa1−xN Cylindrical Quantum Dot

Abstract

Based on the framework of the effective-mass approximation, the ionized acceptor bound exciton (A−, X) binding energy and the emission wavelength are investigated for a cylindrical wurtzite (WZ) GaN/AlxGa1−xN quantum dot (QD) with finite potential barriers by means of a variational method. Numerical results show that the binding energy and the emission wavelength highly depend on the QD size, the position of the ionized acceptor and the Al composition x of the barrier material AlxGa1−xN. The binding energy and the emission wavelength are larger when the acceptor is located in the vicinity of the left interface of the QD. In particular, the binding energy of (A−, X) complex is insensitive to the dot height when the acceptor is located at the left boundary of the QD. The ionized acceptor bound exciton binding energy and the emission wavelength are both increased if Al composition x is increased.