Dynamics of nonequilibrium electrons on neutral center states of interstitial magnesium donor in silicon

Abstract

Subnanosecond dynamics of optically excited electrons bound to excited states of neutral magnesium donor centers in silicon has been investigated. Lifetimes of nonequilibrium electrons have been derived from the decay of the differential transmission at photon energies matching the intracenter and the impurity-to-conduction band transitions. In contrast to hydrogenlike shallow donors in silicon, significantly longer lifetimes have been observed. This indicates weaker two-phonon and off-resonant interactions dominate the relaxation processes in contrast to the single-intervalley-phonon-assisted impurity-phonon interactions in the case of shallow donors in silicon.