Abstract

The capture of free carriers by shallow impurities in doped crystalline semiconductors represents an important relaxation process which is of particular relevance for hot carrier transport. Until now, those phenomena have been investigated by stationary transport or noise measurements, giving the approximate cross sections of electron or hole trapping for a number of shallow donors or acceptors, respectively [1]. However, very limited information exists on the underlying scattering dynamics by which carriers are transferred from continuum states in the respective bands to localized states of the impurity atoms. In this paper, we discuss the first direct time-resolved observation of the ultrafast recombination of free holes with ionized shallow acceptors in a III-V semiconductor. Our data give evidence of hole capture on a time scale of 50 ps where emission of single longitudinal-optical phonons leads to a direct population of the acceptor ground state.

© 1992 The Author(s)