Influence of carbon coated pBN crucible on crystal growth of Cd0.9Zn0.1Te for radiation detector applications

In the Bridgman and Vertical Gradient Freeze (VGF) techniques, it is common to use a high purity crucible for crystal growth. One disadvantage of pBN crucibles is associated with the crucible material interacting with the melt during the growth cycle. Using pBN crucibles for the growth of CZT, we have observed that the crucible does in fact interact with the CZT melt. To prevent this interaction, a vacuum carbon coating system for applying a carbon coating to pBN crucibles has been developed. The effects of crucible use with time are studied, as are the compositional and device properties of the bulk material. GDMS measurements are used to investigate on broron and nitrogen content, among other trace impurities found in the crystal. Devices harvested from ingots grown using cc-pBN exhibit high resistivity and good functionality as room temperature gamma ray detectors.