On mechanism of the growth of the optical transitions strengths in Ge-quantum dots embedded in Si matrix

Abstract

The Si/Ge heterostructure, the active area of which is composed of the Ge quantum dots (QD), is investigated theoretically. The high density of the Ge QDs array cannot be the dominant feature in the choice of an adequate model that can explain the experimentally observed increase in the intensity of luminescence. In the basis of such model the conditions are laid that increase the oscillator strength of exciton due to the ‘retraction’ of electronic states into the Ge QD core.