Journal of Crystal Growth, Vol.311, No.9, 2641-2647, 2009
Preferential orientation of Te particles in melt-grown CZT
Cadmium zinc telluride (Cd1-xZnxTe or CZT) has proved to be a useful material for semiconductor gamma-ray spectrometers and other electro-optic devices. It is often grown Te-rich to optimize its electrical characteristics, but this off-stoichiometric growth leads to the formation of semimetallic Te particles in the semiconducting host crystal. These particles can impair device performance and their formation needs to be inhibited, if possible, during growth. In this study, characterization of several particles of different faceted shapes revealed that most of the Te particles were preferentially oriented with the {101}(CZT)parallel to{(1) over bar2 (1) over bar0}(Te). A secondary orientation relationship was also observed as {11 (1) over bar}(CZT)parallel to{01 (1) over bar1}(Te) for one of the {111}(CZT) family of planes. One of the particles exhibited {110}(CZT)parallel to{01 (1) over bar0}Te, and (001)(CZT)parallel to{0001}(Te). Particles were often found on {111}(CZT) twin boundaries and, in these cases, it was possible to assign specific orientations with respect to the twin plane. Ab initio calculations predicted a good lattice match between the {0001}-plane of Te aligned with the {111}-plane of CZT, however, no such particle orientation was observed. Observations of strained and polycrystalline Te particles are also discussed with relevance to the ab initio model and to impacts on electronic properties. (C) 2009 Published by Elsevier B.V.
Keywords:Characterization;Crystal morphology;Interfaces;Bridgman technique;Semiconducting cadmium compounds