Photocarrier distribution and photomagnetoelectric effect in semiconductors near the threshold of stimulated emission

Photoconductivity experiments with pulsed laser radiation and experiments on optically excited laser action in semiconductors are closely related. In this paper the photomagnetoelectric current, which is given by the surface concentration of non-equilibrium carriers is analyzed within the phenomenological coupled rate equations for electrons and photons, respectively. A saturation of surface concentration near the laser threshold is predicted, which should be observable at low temperatures. From gain calculations for the small-gap semiconductor PbSnTe the linear relationship between maximum gain and nonequilibrium carrier concentration is confirmed.