Cooling process optimization to control Te inclusions for improving CdZnTe detector performance

Investigation of Te inclusion distribution in CdZnTe crystals treated by the cooling process at different rates indicated that cool slowly at 10–20 K/h caused the emergence of lower concentration but larger size Te inclusions, with a high level total volume fraction, decreasing the IR transmittance. When cooled fast, the dimension of Te inclusions reduced and the concentration increased, even the faster cooling rate, the higher the concentration; moreover the IR transmittance improved. The measurement of energy spectrum demonstrated that Te inclusions of large size or high concentration induced by slow or too fast cooling rate respectively degenerate spectroscopy performance. Cooling at 40–50 K/h presented an optimized process, which retained a certain amount but small size Te inclusions and kept a low total volume fraction, expressing better energy resolution.