Binding energy of charged excitons bound to interface defects of semiconductor quantum wells

We present a model that takes into account the interface-defects contribution to the binding energy of charged excitons (trions). We use Gaussian defect potentials and one-particle Gaussian basis set. All the Hamiltonian defect terms are analytically calculated for the s-like trial wave functions. The dependence of the binding energy and of the trion size on the quantum-well width and on the defect size are investigated using a variational method for ${\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}/\mathrm{A}\mathrm{l}}_{0.3}{\mathrm{Ga}}_{0.7}\mathrm{As}$ quantum wells. We show that even in the case of strictly structural defects the trion is more strongly affected than the exciton.