Star-like' defects in Cd-annealed CdZnTe crystalsan experimental study of their origin and formation mechanism

Abstract

We conducted low-temperature annealing experiments at temperatures slightly above and below the melting point of Te to clarify the effects of the state of Te inclusions (solid or liquid) upon the formation of star-like' defects in Cd-annealed CdZnTe (CZT). We also carried out post-growth annealing experiments with and without using Cd vapor to clarify the mechanism of formation of such defects. We demonstrated that these star-like' defects are due to the reaction between in-diffused Cd atoms and the molten Te inclusions, but we found no observable one-to-one' correlation between star-like' defects and Te inclusions. The non-uniform distribution of Te inclusions in the CZT matrix could account for this phenomenon since the punching distance of the dislocations depends on the volume fraction of inclusions within the matrix.