Effect of annealing on near-stoichiometric and non-stoichiometric CdZnTe wafers

The effect of annealing on near-stoichiometric and non-stoichiometric CdZnTe crystals was investigated by means of various optical and structural techniques including infrared (IR) transmission, transmission electron microscopy (TEM), X-ray double crystal rocking curve, secondary ion mass spectroscopy (SIMS), Raman scattering (RS), and Rutherford backscattering spectroscopy (RBS). Results indicate that annealing can effectively reduce Te precipitates, especially larger ones, through thermomigration process, and purify the wafers by gettering some impurities. Additionally, annealing improves slightly the crystallinity of near-stoichiometric crystals but degrades the microstructure of non-stoichiometric wafers. The investigation implies that the annealed near-stoichiometric CdZnTe wafers are suitable as substrates for the growth of quality Hg_{1 - x}Cd_xTe epitaxial films.