Characterization of precipitates in CdTe and Cd 1− xZn xTe grown by vertical Bridgman-Stockbarger technique

Abstract

Different polishing solutions were tested for exposing precipitates in CdTe and Cd 0.96Zn 0.04 single crystals grown by vertical Bridgman-Stockbarger technique. A solution of 5–7% Br 2 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 μm 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 0.96Zn 0.04Te 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.