Reduction of Te-rich phases in Cd_1-xZn_xTe (x = 0.04) crystals

Cd_1-xZn_xTe crystals are annealed in Cd/Zn vapours to eliminate Te-rich phases. During the saturated Zn partial pressure annealing and the high-temperature annealing under low P_Zn, large Te-rich phases gather at the slice surface through thermo-migration. This process increased the stress in the bulk crystals and caused the formation of defects such as twins, stacking faults, and dislocations. The IR transmission is greatly improved by annealing the slices under saturated P_Zn and then removing a layer from the surface of the slices with a thickness of about 50 μm. For Cd_1-xZn_xTe slices annealed at low temperature and low Zn partial pressure, the reduction of the Te-rich phases greatly depends on the diffusion of the atomic defects.