Photoionization cross-section in a GaAs spherical quantum shell: the effect of parabolic confining electric potentials

Abstract

Theoretical study on binding energies due to a centred charged impurity and the associated photoionization cross-section (PCS) in a spherical shell are presented. This was achieved by solving the Schrödinger equation within the effective mass approach. Intrinsic to the spherical quantum shell may be the parabolic potential or the shifted parabolic potential, each superimposed on an infinite spherical square well. Results indicate that the parabolic potential enhances binding energies while the shifted parabolic potential diminishes them. These electric potentials considerably modify photoionization cross section in two ways. One, the parabolic potential blueshifts peaks of PCS while the shifted parabolic potential redshifts the peaks. Second, the parabolic potential decreases the magnitude of the peaks of the PCS while the shifted parabolic potential increases the magnitudes of the peaks. In essence, these two potential may be used to manipulate PCS in quantum structures.