BINDING-ENERGIES AND DENSITY OF IMPURITY STATES IN SPHERICAL GAAS-(GA,AL)AS QUANTUM DOTS

The binding energies of hydrogenic donor in both finite and infinite G aAs-(Ga,Al)As spherical quantum dots are calculated as a function of t he donor position for different radii within the effective-mass approx imation. It is observed an enhancement of the binding energy of donors in quantum dots when compared to results in quantum wells and quantum -well wires, which is an expected consequence of the higher geometrica l electronic confinement in these systems. The density of impurity sta tes as a function of the donor binding energy was also calculated. As a general feature it presents structures associated with special impur ity positions that may be important in the understanding of the absorp tion and photoluminescence experiments of doped quantum dots.