Photoionization of deep impurity centers in quantum well structures

The absorption of light by photoionization of deep impurity centers in quantum well heterostructures is studied theoretically using a model with a maximally localized potential. Analytic expressions are found for the photoionization cross sections for light polarized perpendicular and parallel to the axis of the structure, disregarding the effect of the impurity potential on the continuum electronic states. The dependence of the frequency variation of the cross section on the charge state of the impurity after photoionization, as well as on the position of the impurity in the structure and the doping profile, is studied qualitatively near the absorption threshold. Fiz. Tekh. Poluprovodn. 33, 451–455 (April 1999)