In the present paper, an analysis of laser action in semiconductors is made, and a condition for population inversion is established. The radiation output is found to be proportional to the deviation from the equilibrium value of the occupancy of the allowed states including the states in the conduction and valence band and also the donor and acceptor states. Possible laser levels are discussed.Following the general analysis, a scheme is proposed for laser action in covalent semiconductors where the top of the valence band and the bottom of the conduction band do not occur at the same value ofk. The scheme consists of simultaneously tunneling electrons into the (000) valley of the conduction band and injecting holes into the valence band. The outstanding feature of the proposed scheme is that it offers a definite possibility for separate amplitude and frequency modulation of the laser output. Various losses associated with the proposed scheme are also discussed.