Demonstration of Energy-Resolved γ-Ray Detection at Room Temperature by the CsPbCl3 Perovskite Semiconductor

The detection of γ-rays at room temperature with high-energy resolution using semiconductors is one of the most challenging applications. The presence of even the smallest amount of defects is sufficient to kill the signal generated from γ-rays which makes the availability of semiconductors detectors a rarity. Lead halide perovskite semiconductors exhibit unusually high defect tolerance leading to outstanding and unique optoelectronic properties and are poised to strongly impact applications in photoelectric conversion/detection. Here we demonstrate for the first time that large size single crystals of the all-inorganic perovskite CsPbCl 3 semiconductor can function as a high-performance detector for γ-ray nuclear radiation at room temperature. CsPbCl 3 is a wide-gap semiconductor with a bandgap of 3.03 eV and possesses a high effective atomic number of 69.8. We identified the two distinct phase transitions in CsPbCl 3 , from cubic ( Pm -3 m ) to tetragonal ( P 4/ mbm ) at 325 K and finally to orthorhombic ( Pbnm ) at 316 K. Despite crystal twinning induced by phase transitions, CsPbCl 3 crystals in detector grade can be obtained with high electrical resistivity of ∼1.7 × 10 9 Ω·cm. The crystals were grown from the melt with volume over several cubic centimeters and have a low thermal conductivity of 0.6 W m -1 K -1 . The mobilities for electron and hole carriers were determined to ∼30 cm 2 /(V s). Using photoemission yield spectroscopy in air (PYSA), we determined the valence band maximum at 5.66 ± 0.05 eV. Under γ-ray exposure, our Schottky-type planar CsPbCl 3 detector achieved an excellent energy resolution (∼16% at 122 keV) accompanied by a high figure-of-merit hole mobility-lifetime product (3.2 × 10 -4 cm 2 /V) and a long hole lifetime (16 μs). The results demonstrate considerable defect tolerance of CsPbCl 3 and suggest its strong potential for γ-radiation and X-ray detection at room temperature and above.