Semiinsulating CdTe

Experimental conditions for the growth of near stoichiometric high-resistivity CdTe single crystals with a minimal concentration of point defects are investigated. The position of the stoichiometric line in the pressure temperature (P-T) phase diagram is evaluated from high-temperature in situ galvanomagnetic, measurements. Calculations based on a model of two major native defects (Cd vacancy and Cd interstitial) show, that a very small variation of Cd pressure P-Cd results in a strong generation of uncompensated native defects. Modelling of room temperature carrier density dependence on the deep defect density N-DD, P-Cd, and annealing temperature T shows, that the range of optimal P-Cd, at which high resistivity can be reached, broadens with increasing N-DD or decreasing T. It is shown that at low T<450degreesC the deep defect density <10(15) cm(-3) is sufficient to grow the high-resistivity CdTe. (C) 2002 Elsevier Science B.V. All rights reserved.