Compensation mechanism of bromine dopants in cadmium telluride single crystals

Cadmium telluride single crystals, doped by Bromine, were grown by Bridgman method and annealed under cadmium overpressure (PCd=102−105Pa) at 800–1100K. Their electrical properties at high- and low-temperature have been investigated. The influence of impurities on the crystal electrical properties has been analyzed by using the defective subsystem model, which includes the possibility of formation of point intrinsic (VCd2−, Cdi2+, VTe2+, Tei2−) and replacement defects (BrTe0, BrTe+), and also point defects complexes (BrTe+VCd2−), (2Br+Te VCd−)0. It was established that the concentration dependence between free charge carriers and annealing process parameters (n(T), n(PCd)) are determined by two dominant defects −BrTe+ and (2Br+Te V2−Cd)0. Their content varies with the annealing temperature and the vapor pressure of the component; the concentration of other defects is much smaller and almost does not influence the electron density. •CdTe crystals, doped by bromine, were grown by the Bridgman method.•Samples were annealed under constant thermodynamic conditions.•Treatment conditions: ~500–1100K under Cd overpressure.•Electrical properties were measured “in situ” using the Hall effect measurements.•A theoretical model for point defect structure of CdTe:Br crystals is proposed.