Thermomigration of Tellurium Precipitates in CdZnTe Crystals Grown by Vertical Bridgman Method

摘要

Te precipitates in CdZnTe have been characterized by x-ray diffraction at room and higher temperatures. From the x-ray results at room temperature, it has been confirmed that Te precipitates in CdZnTe have the same structural phase as observed in elemental Te under high pressure. The x-ray results at higher temperature indicate that Te precipitates melt around 440℃. CdZnTe samples containing Te precipitates have been annealed at temperatures below and above 440℃ with thermal gradient of ～70℃/cm. Results of the observation with infrared microscope before and after the annealings indicate distinct occurrence of thermomigration of Te precipitates in samples annealed at temperature above 440℃ compared with ones annealed at temperature below 440℃. Thermomigration velocity obtained from these results is ～50 μm/h. The average value for the effective diffusion coefficient of the metallic atoms in Te precipitates calculated by using the thermomigration velocity is ～3 x 10~(-5) cm~2/s.