Energy spectrum of centres in spherical quantum dots

Abstract

The properties of negatively charged donor centres have been studied for semiconductor quantum dots with the finite spherically symmetric confinement potential. The energy levels of the ground state and the excited states of both the spin-singlet and spin-triplet configurations have been calculated by variational means. It has been shown that the excited states of the centre in quantum dots are bound for sufficiently strong confinement potential. The conditions of binding for the excited states have been determined as functions of the potential-well depth and quantum-dot radius. The formation of the bound excited states of the centre is a new property, which results from the confinement of electrons in the quantum dot. A possible application of the present results to the ion trapped in a microcavity is discussed.