Hydrogenic Donor in a Spherical Quantum Dot with Different Confinements

Binding energies of a hydrogenic donor in a spherical GaAs quantum dot surrounded by Ga_1-xAl_xAs matrix are calculated. The results are presented for realistic barrier heights corresponding to different values of x (x<0.4). The calculations are performed under two different conditions: (i) a spherical dot with square well confinement and (ii) a dot with parabolic potential well confinement. The results show that (i) the donor ionization energies are always higher under parabolic confinement as compared to a dot of the same radius under square well confinement and (ii) the oscillator strengths coupling ground state with excited states are two orders larger under parabolic confinement. Our results are in agreement with the results of other researchers.