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The defect structure of donor-doped Te-rich CdTe is studied theoretically within quasi-chemical formalism and experimentally in heavily In-doped CdTe by in situ high temperature galvanomagnetic measurements in the temperature interval 900 -200 °C. The experimental data are evaluated within defect model optimized to recent high temperature experiments and assuming doping-induced band gap renormalization. We show that a proper thermal treatment can be conveniently used for the optimization of room temperature electric properties and for a preparation of the semi-insulating detector grade material with a deep level doping below the limit 10 13 cm -3 demanded in the detector industry.

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CdTe crystals are used widely for manufacturing gamma-ray radiation sensors, and we can improve their properties if we eliminate as many as possible of their Te inclusions. In this paper, we describe our two modes of removing them; first, we used the traveling heater method for growing them, and then we applied post-growth cooling, for which we used a special slow-cooling program. Here, we placed the CdTe ingot, containing inclusions, into a quartz container, and moved a narrow heater zone along it. The molten inclusions moved together with the hot zone, and, at end of the process, they were concentrated heavily at the ingot's surface. Consequently, very few inclusions were observed in much of the CdTe ingot. Hall effect measurements showed that after such annealing the value of the carrier mobility was increased significantly, and the concentration of ionized centers was reduced. One major advantage of this treatment, compared to thermal annealing alone, is that both the inclusions and impurities are eliminated simultaneously.

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