Effect of superheating and fast cooling on Te inclusions of Cd0.9Zn0.1Te:In crystals grown by vertical gradient freezing

The goal of this paper is to study the effect of superheating and fast cooling conditions on the defects of CdZnTe crystals especially Te inclusions.The paper reports characterization of the crystal defects using IR microscopy and Fourier Transform Infrared spectroscopy. Three ingots of CdZnTe doped with Indium were grown by Vertical Gradient Freezing. Ingot A and B were grown with superheating temperatures of 26 °C and 56 °C respectively. In the last case the growth process was followed by a fast cooling.The results show that the size of Te inclusions was greatly reduced and the crystal quality was improved after higher superheating and fast cooling.

► Superheating by 1130 °C was not sufficient to complete the reaction between Cd and Te.
► Low superheating leads to the formation of a conical shaped polycrystalline region.
► Increasing the superheating temperature to 1160 °C improved the material homogeneity.
► Ingot grown using superheating and fast cooling contains the smallest size of Te inclusions.
► FTIR spectra showed excellent uniformity and high value of IR transmission.