Three-dimensional mapping of tellurium inclusions in CdZnTe crystals by means of improved optical microscopy

One of the main problems connected with the exploitation of CdTe and CdZnTe crystals for the preparation of X-ray imaging devices is the presence in the matrix of inclusions ,mainly due to tellurium excess. It is important to setup characterization methods that permit one to map in three dimensions the presence and the diameter of inclusions. This is a key point for (both) a better understanding of the inclusion-formation mechanism and for the evaluation of crystal quality. For this purpose, we developed a system that can be implemented on standard transmission optical microscopes. The use of this tool in the characterization of Bridgman grown CdZnTe samples allowed us to uncover interesting features in the tellurium inclusion distribution.