Temperature-gradient post-growth annealing of CdMnTe wafers for nuclear radiation detection applications

Cadmium Manganese Telluride (CdMnTe) is one of the semiconductor materials recently being developed as X-ray and gamma-ray detectors capable of operating at room temperature. This paper presents the results of temperature-gradient post-growth annealing of CdMnTe crystals grown by Bridgman technique. Migration of Te inclusions from the low-temperature side to the high-temperature side of CdMnTe wafers was recorded for an annealing temperature of 715 °C at a temperature gradient of 24 °C/cm and annealing time of 30 minutes. Size reduction and elimination of Te inclusions were also recorded for a CdMnTe wafer annealed at 730 °C with a temperature gradient of 18 °C/cm for 18 hours. A two-dimensional analysis of an 810 × 1350 μm2 sample area showed a 76% reduction in the Te-inclusion concentration.