Fochuk P. The nature of point defects in doped CdTe

The thesis is devoted to the investigation of point defect formation and interaction processes, chemical nature determination in CdTe single crystals, undoped and doped by ІІІА, IVA, VA і VІІA group elements. On the base of quasichemical reaction theory the dominant native point defects in CdTe in homogeneity regions were determined by experiment at high temperature equilibrium. The formation enthalpies for the two native and three foreign donors were calculated. The thermodynamic constants set optimization allows us to carry out the modeling of point defects concentration vs temperature and component vapor pressure. It was revealed four main point defects behavior types in CdTe<In> crystals, what is determined mainly by In content. It was established that Tl forms the substitution solid solution and acts as a donor. Ge, Sn and Pb form proportionate quantities of associates with Cd vacancies and substitution defects. Sb replaces Te atoms and produces a level located at 0.29 eV above the valence gap. CdTe doping by halogens leads to the self-compensation processes intensification and substantial Cd vacancy content increasing.