We present a detailed theoretical investigation of resonant states induced
by shallow accepters in uniaxially strained semiconductors. By applying Dir
ac's approach and using the Coulomb potential of an acceptor impurity, we h
ave obtained the amplitude of resonant scattering, the probability of coher
ent capture and emission of holes by resonant state, and the characteristic
features of the resonant state. The modified dispersion law and density-of
-states of valence band by the resonant states have also been derived. The
energy dependence of optical transition probability between resonant and lo
calized impurity state have been calculated. The theoretical investigation
of a new mechanism for carrier population inversion in strained semiconduct
ors under an electric field has been presented. It has been shown that the
mechanism is the result of a coherent capture emission type inelastic scatt
ering of holes by resonant states. The calculation based on our theory for
uniaxially strained p-Ge explains the recently observed lasing phenomena in
THz frequency region.