High-Resolution γ -Ray Spectroscopy in Capacitive Frisch Grid CdZnTeSe Detectors

The quaternary semiconductor Cd $_{{0}.{9}}$ Zn $_{{0}.{1}}$ Te $_{\text {1-{y}}}$ Se _y (y =0.02–0.03), exhibiting exceptionally high compositional homogeneity and low trap concentrations, has recently emerged as a robust semiconductor crystal for room-temperature detection of gamma-rays. In this letter, we report a high energy resolution of 1.4% achieved for a 3.4 mm $\times 3.4$ mm $\times 9.7$ mm virtual Frisch grid detector when exposed to 662-keV gamma rays, without any digital correction. The above energy resolution was obtained at a fraction of the bias voltage needed to obtain such high energy resolution in most CZTS detectors. A mobility-lifetime product of $4.42\times 10^{-{3}}$ cm ² /V and a drift mobility of 882 cm ² /V-s for electrons were obtained using a single polarity Hecht plot and the time-of-flight method, respectively. The superior electron transport properties enabled us to calculate the electron-hole pair creation energy (4.47 eV) experimentally for the first time in CZTS. Biparametric correlation studies were performed, which revealed the extraordinary potential of further improvement in the detection performance through digital corrections and can be applied to other wide or ultra-wide bandgap semiconductors.