Resonant acceptor states and terahertz stimulated emission of uniaxially strained germanium

The stimulated emission spectrum of uniaxially strained p-Ge is presented. The energy spectrum of the states of a shallow acceptor in Ge under uniaxia l compression is calculated. The threshold pressure at which the acceptor s tate split off from the ground state becomes resonant is found. The pressur e dependence of the width of this resonant level is calculated. The stimula ted emission lines are identified. In particular, it is shown that the prin cipal emission peak corresponds to the transition of holes from the resonan t 1s (1s(r)) state to the local p(+/-1) state. The probabilities of optical transitions are calculated. A mechanism of population inversion due to the intense resonant scattering of hot holes with an energy corresponding to t he position of the 1s(r) level is proposed. (C) 1999 American Institute of Physics. [S1063-7761(99)00901-4].