Thermal instability of a semiconductor in a lasing beam

The thermal balance is considered in an intrinsic semiconductor in the presence of a laser beam with a photon energy less than the width of the forbidden band, as a result of which absorption by free carriers plays the principal role. It is shown that a radiation power threshold exists above which the stationary temperature distribution is impossible. For typical values of the parameters the threshold power is 1 kW, and the time required for instability to develop is 10^–3–1 sec.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 15, No. 1, pp. 33–37, January, 1972.The author is indebted to V. L. Bonch-Bruevich, Yu. V. Gulyaev, I. P. Zvyagin, P. E. Zil'berman and A. G. Mironov for discussing the work.