Growth of Cd0.9Zn0.1Te1-ySey Single Crystals for Room-Temperature Gamma Ray Detection

Quaternary Cd0.9Zn0.1Te1-ySey (CZTS) single crystals, a novel room-temperature nuclear radiation detector semiconductor material, have been grown using a modified vertical Bridgman method (VBM) and a traveling heater method (THM). The percentage concentration of selenium in the VBM-grown crystal was 3% and that in the THM-grown crystal was 2%. While the THM Frisch collar detector (4.4 x 4.4 x 10.7 mm(3)) produced a highly resolved pulse height spectra (PHS) with a resolution of similar to 1.06% for 662-keV gamma rays without any correction, the VBM-grown detector (10 x 10 x 2 mm(3)) offered a high-energy resolution of similar to 2% after the application of a digital bi-parametric correction. The high-resolution performance of these detectors has been attributed to the addition of Se in the Cd0.9Zn0.1Te (CZT) matrix. Ab-initio calculations based on density functional theory (DFT) also confirmed that the addition of Se in the CZT matrix helps to reduce the formation of Te-Cd and the Te-Zn antisites. The VBM-grown crystals were characterized using powder X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). While the XRD results revealed sharp diffraction peaks confirming the crystalline nature of the grown crystal, the EDS results confirmed the targeted stoichiometry of the elemental composition. The bulk resistivity of the grown crystal was calculated to be similar to 3 x 10(10) Omega-cm from the current-voltage characteristics recorded at room temperature in a planar configuration, ensuring that the grown CZTS crystals have low, dark current as required for detector-grade crystals.

Automated summary

Novel room-temperature nuclear radiation detector semiconductor material Quaternary Cd0.9Zn0.1Te1-ySey (CZTS) single crystals were successfully grown using modified vertical Bridgman method and traveling heater method. The addition of selenium in the Cd0.9Zn0.1Te (CZT) matrix improved the resolution performance of the detectors by reducing the formation of Te-Cd and Te-Zn antisites, confirmed by ab-initio calculations. The grown crystals were characterized using powder X-ray diffraction and energy dispersive X-ray spectroscopy, showing high purity and targeted stoichiometry.