Perturbation calculation of donor states in a spherical quantum dot

An attempt is made to derive the donor states associated with the ground and a few higher levels in spherical quantum dot (QD) using the perturbation method. The binding energies are computed for GaAs QD as functions of the dot size and the impurity position. The results show that the impurity binding energies decrease with the increase in dot dimension. The binding energies are also found to show a strong dependence on the location of the impurity within the dot. For s-levels, the donor binding energy is maximum for an on-centre impurity, while for p and d-levels, the binding energy maxima occur for a donor located off the dot centre. (C) 1998 Published by Elsevier Science Ltd: All rights reserved.