Enhancing Gamma-Ray\nSpectral Resolution in Perovskite\nCsPbBr<sub>3</sub> Detectors through Dark Current Reduction with Guard\nRing Electrodes

Halide perovskites, considered a new generation of semiconductors,\nhave demonstrated notable advancements in nuclear radiation detection,\nhighlighting their cost-effectiveness in fabrication. However, great\nchallenges can arise from crystal edge effects associated with imperfect\nsurface status, likely resulting in high surface leakage currents\nand incomplete charge collections, which greatly impede the obtaining\nof excellent spectroscopic capability. In this work, a guard ring\nconfiguration for shielding edge effects was designed on a perovskite\nCsPbBr<sub>3</sub> detector for spectral optimization and long-term\nstabilization. The implementation of a guard ring resulted in significantly\ndecreased and stable leakage currents passing through the central\ncollecting electrode. As a result, the bulk leakage current from the\nactive region was reduced by approximately 80%. Consequently, the\n122 and 136 keV photopeaks in <sup>57</sup>Co γ-ray spectra\nwere well resolved, with an energy resolution improvement from ∼9.8\nto 4.8% at 122 keV. Notably, the low energy tailing of the photopeak\nhas been greatly weakened by reducing the edge effects.