Microscopic theory of erbium ion de-excitation processes in silicon

Abstract

Abstract There are some evidences that Er related optically active centers in silicon form donors with binding energy about 150–250 meV, and the excitation of erbium occurs in a result of Auger recombination process of the electron bound to the donor and a free hole or bound exciton. It is supposed that there are two effective de-excitation processes: (i) back transfer process to recombination of electron–hole pair and (ii) collision with free carriers. Both of them are being theoretically studied in this paper. The probability of back transfer increases dramatically with temperature rising. The collision with free carriers is the dominating de-excitation process at low temperature. It was shown that the perturbation of wave function of free carriers by the ionized Coulomb donor center associated with Er ion increases the probability of the Er-ion de-excitation by free electrons dramatically and practically supresses the de-excitation by holes. The Auger de-excitation process, in which the energy from Er ion is consumed by electron going from Er related donor to the conduction band, has been investigated as well.