Photoionization cross section of a D-2(+) complex in quantum dots: the role of donor atoms configuration

Abstract

This study reports a theoretical investigation on the electronic spectrum and the photoionization cross section of a singly ionized double donor complex D_2^+ confined in a two-dimensional quantum dot with Gaussian confinement potential. Using the diagonalization method and the effective mass approach, the energy spectrum, binding energy, and photoionization cross section of the D_2^+ complex were obtained for different quantum dot sizes and internuclear distances. The numerical results obtained reveal that the size of the geometric confinement and the configuration of the donor atoms significantly affect the binding energy, equilibrium distance and photoionization cross section of the D_2^+ complex. As a result, the electronic spectrum and optical responses of the artificial molecule D_2^+ complex can be fine-tuned simply by controlling the confinement size and impurity configuration. Also, we conclude that a significant increase in the amplitude of the photoionization cross section is observed when the donor atoms are symmetrically positioned on the x-axes. In addition, the exact convergence of the results obtained in the limiting case to the known results demonstrated the suitability of the method used in this study.