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

Quaternary Cd
_0.9
Zn
_0.1
Te
_1-y
Se
_y
(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 ( 4.4×4.4×10.7 mm $^{3}$ ) produced a highly resolved pulse height spectra (PHS) with a resolution of ~1.06% for 662-keV gamma rays without any correction, the VBM-grown detector ( 10×10×2 mm $^{3}$ ) offered a high-energy resolution of ~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 Cd
_0.9
Zn
_0.1
Te (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 ~ 3×10
¹⁰
Ω-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.