Enhancing Gamma-Ray Spectral Resolution in Perovskite CsPbBr3 Detectors through Dark Current Reduction with Guard Ring Electrodes

Halide perovskites, considered a new generation of semiconductors, have demonstrated notable advancements in nuclear radiation detection, highlighting their cost-effectiveness in fabrication. However, great challenges can arise from crystal edge effects associated with imperfect surface status, likely resulting in high surface leakage currents and incomplete charge collections, which greatly impede the obtaining of excellent spectroscopic capability. In this work, a guard ring configuration for shielding edge effects was designed on a perovskite CsPbBr3 detector for spectral optimization and long-term stabilization. The implementation of a guard ring resulted in significantly decreased and stable leakage currents passing through the central collecting electrode. As a result, the bulk leakage current from the active region was reduced by approximately 80%. Consequently, the 122 and 136 keV photopeaks in 57Co γ-ray spectra were well resolved, with an energy resolution improvement from ∼9.8 to 4.8% at 122 keV. Notably, the low energy tailing of the photopeak has been greatly weakened by reducing the edge effects.