Binding energies and photoionization cross-sections of donor impurities in GaN/AlxGa1−xN spherical quantum dot under hydrostatic pressure

Abstract

In this paper, the binding energy and photoionization cross-section of donor impurity state in [Formula: see text] quantum dot structure are studied theoretically by using variational method. The variation of binding energy and photoionization cross-section with core and shell sizes at different impurity locations under hydrostatic pressure is calculated numerically. The results show that the binding energy decreases monotonously with the core size at different impurity locations for [Formula: see text] core/shell quantum dot. In contrast, for the inverted core/shell quantum dot, the binding energy exhibits different trends with the increase of core size at different impurity locations. But the binding energy decreases monotonically with the shell size for both of them. Moreover, when the photon energy is approximately equal to the donor binding energy, the peak of the photoionization cross-section appears. There will be different peak shifts under different conditions, and its peak intensity increases with the increase of core and shell sizes. When the hydrostatic pressure is applied, the binding energy and the peak strength of the photoionization cross-section increase with the increase of the pressure.