Compensating effect of Sn impurity in cadmium telluride

The equilibrium characteristics of CdTe:Sn crystals grown by the Bridgman method are investigated. The impurity content in the samples was in the range N_Sn=10¹⁶-10¹⁸ cm^–3. It is established that for a specific (critical) Sn concentration (N_cr) a sharp increase in the resistivity occurs and the material becomes semi-insulating with n-type conductivity. The value of N_cr is determined (7·.10¹⁶ cm^–3). No correlation is noted between the properties of the semi-insulating CdTe:Sn samples and the impurity content. The effect of heat treatment (800°C, P_Cd=min) on the properties of the semi-insulating CdTe:Sn samples is studied, and it is established that the equilibrium characteristics of the crystals (mobility, carrier concentration) are practically unchanged.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 66–69, April, 1986.