Energy spectra of an exciton bound to a charged impurity in quantum dots

The energies of the low-lying states for an exciton (X) trapped in a two-dimensional quantum dot by a charged impurity are calculated by using the method of few-body physics. This configuration is called a (D+,X) center or a (A−,X) center. The dependences of the energies of the low-lying states of the (D+,X) and the (A−,X) centers on the electron-to-hole mass ratio σ, the dot radius R and the dot thickness are obtained. We compare our results with those of X+ and X−.