Verzhak I. Effect of heat treatment on the defect spectra in CdTe crystals, doped with donor impurities

Using the method of high-temperature Hall effect measurements, the time dependence of the CdTe crystal electrical parameters as a function of heat treatment conditions were studied. Donor (indium or bromine) doped CdTe was grown by the Bridgman method. The optimal concentration of dopant in CdTe:In crystal allowed to obtain the material with a high resistance. A two-stage annealing procedure of these samples was proposed in order to obtain high-resistance and structurally perfect material with no visible (in the IR microscope) second phase inclusions. Using annealing under Cd overpressure the inclusions of second phase were eliminated. The next treatment under Te saturation conditions restored the initial material high resistance. The model of point defect ensemble in CdTe:In crystals at high and room temperatures were constructed. It allowed predicting and creating a material with low concentration of charge carriers. The high- and low-temperature measurements of CdTe, heavily doped by bromine, under cadmium and tellurium overpressure were studied. The results, obtained for this donor impurity, were explained in the framework of dopant self-compensation phenomena and Kroger’s theory.