Development of Large Size and Low Cost Cadmium Zinc Telluride Single Crystals for Improved Room Temperature Radiation Detectors used for National Security

60972 Cadmium Zinc Telluride (CdZnTe) is an important material for detectors used for national security. However, the production of CdZnTe, dominated by the High Pressure Bridgman technique for a decade, has suffered from low-yields (1-4%) and small device sizes (1-3 cm3). This project will develop an alternative Modified Vertical Bridgman, CdZnTe crystal growth technique with higher yield and larger-sizes, leading to higher volume detectors which are not available today. In Phase I, 50 cm3 large-size single CdZnTe crystals were produced with a high yield of over 50%. The crystals demonstrated an unprecedented mobility-lifetime product for electrons without compromising bulk resistivity. The pixellated and co-planar grid detectors performed with excellent energy resolutions. In Phase-II, a 3¿ diameter growth technique will be developed. Commercial Applications and Other Benefit as described by the awardee: These large-size single crystals, coupled with higher yields of CdZnTe single crystals should lower costs and further improve detector performances, especially for high-resolution room temperature radiation detectors with low-cost for national security and nuclear medicine