Photoionization Cross Section in Low-Dimensional Systems

Abstract

A theoretical investigation of the effects of the parabolic, shifted parabolic, hill-like, and cup-like parabolic confining electric potentials on photoionization cross section (PCS) in a spherical quantum dot is presented. Each of the parabolic potentials is superimposed on an infinite spherical square quantum well (ISSQW) potential. The parabolic potential blueshifts the peaks of the PCS, while the shifted parabolic potential causes a redshift. As the so-called strength of cup-like parabolic potential is increased, the peak of the PCS becomes redshifted for the s ! p transition, but blueshifted for the p ! d, d ! f (and so forth) transitions. On the contrary, an increase in the strength of the hill-like parabolic potential blueshifts peaks of the PCS for s ! p transitions, while it redshifts those of transitions between higher states.

Variation of the Photoionization Cross-Section with the Position of a Hydrogenic Donor Impurity in a Gallium Arsenide Quantum Well Dot of Square Cross-Section

“…They observed that both the binding energy and the photoionization cross-section depended strongly on the layer thickness and photon energies. Based on the aforementioned observations that electronic and opto-electronic devices depend upon how electrons inside materials behave and how they are influenced by external perturbations which may be electrical [29][30][31], magneti c [32], electromagnetic, mechanical, hydrostatic pressure, this study has looked into the dynamic behavior of the photoionization cross-section. The variation of the photoionization cross-section with the incident photon frequency and with the position of the hydrogenic donor impurity in a square quantum well dot is determined using variational technique.…”