The possibility of creating silicon lasers based on specific few-atomic structural imperfections of a silicon crystal is discussed. These imperfections differ substantially from other defects of the crystal in their high photon emissivity, which is a consequence of zero-phonon optical transitions between the localized electron states of the defects considered. A simple model of basic electron processes in the active region of the laser crystal is proposed. Such lasers can operate in the quantum energy range from 0.4 to 1.1 eV at temperatures less than 100 K in a continuous mode. An injection way of excitation and current modulation of the emission intensity up to gigahertz frequencies are possible. The main difficulty in manufacturing such devices is the nonselectivity of today's radiation methods of forming emissive centers in silicon crystals. This difficulty may be obviated by using promising nanotechnology methods of fabrication of the lasers considered. (C) 2007 Elsevier Ltd. All rights reserved.