ENERGY-SPECTRUM OF D--CENTERS IN SPHERICAL QUANTUM DOTS

The properties of negatively charged D- donor centres have been studie d for semiconductor quantum dots with the finite spherically symmetric confinement potential. The energy levels of the ground state (1(1)S) and the excited states of both the spin-singlet (1(1)P, 1(1)D, 2(1)S) and spin-triplet (1(3)P, 1(3)D, 2(3)S) configurations have been calcul ated by variational means. It has been shown that the excited states o f the D- centre in quantum dots are bound for sufficiently strong conf inement potential. The conditions of binding for the excited states ha ve been determined as functions of the potential-well depth and quantu m-dot radius. The formation of the bound excited states of the D- cent re is a new property, which results from the confinement of electrons in the quantum dot. A possible application of the present results to t he H- ion trapped in a microcavity is discussed.