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Infrared microscopy and scanning electron microscopy with energy dispersive spectroscopy were employed to characterize etch pits formed on CdTe and (Cd,Zn)Te surfaces with E-solution, EAg, Bagai and Nakagawa etchants. Some of the larger flat-bottomed triangular etch pits on the (111)A or (111)B surfaces originated from precipitates. Thus, the etch pit density may differ from the true dislocation density by the presence of etch pits from precipitates.

Different polishing solutions were tested for exposing precipitates in CdTe and Cd(0.96)Zn(0.04) single crystals grown by vertical Bridgman-Stockbarger technique. A solution of 5-7% Br2 in methanol and E-solution were both effective. High resolution scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) was employed to characterize those exposed precipitates. Most of the polyhedral-shaped Te precipitates with a size range from 3 to 20 microns had voids inside. Partially dissolved Te precipitates were observed in CdTe samples that had been annealed in Cd vapor at 700 C for 10 min. Isolated areas mis-oriented from the matrix were observed in CdTe and Cd(0.96)Zn(0.04)Te that had been annealed in Cd vapor at 700 C for 20 and 50 h, respectively. Te precipitate images were recorded with EDS. By SEM/EDS, Cd-rich precipitates were observed in some Cd-annealed CdTe. C and Na impurities were detected in some Te precipitates.