Quantifying Charge Sharing in Pixelated FAPbBr 3 Single Crystal Radiation Detectors

ABSTRACT Charge sharing is known to limit the spatial resolution of pixelated semiconductor radiation detectors. While halide perovskite single‐crystal detectors have demonstrated excellent sensitivity for x‐ray detection, a systematic, mechanism‐resolved study of charge sharing in these materials has been lacking. Here, we investigate the origins, suppression, and residual limits of charge sharing in single‐crystal FAPbBr 3 detectors using a combination of electrode architecture, bias control, and multi‐modal illumination. Weighting‐potential analysis establishes the geometric origin of induced neighbor signals, while spatially resolved laser measurements isolate diffusive and inductive contributions under controlled conditions. Current‐mode x‐ray experiments demonstrate substantial confinement of shared current, depending on device geometry and operating conditions, through the introduction of a guarding electrode, reducing neighbor signal fractions to an average of 4.8%. Extending this framework to γ ‐ray detection with 57 Co and 241 Am sources reveals energy and bias‐dependent residual sharing, with probabilities of measuring a coincident event on the reference and neighbor pixels of 8.2% and 5.8%, respectively. Devices have pixel gaps of 100 µm, guard ring widths of 200 µm, crystal thickness of 2 mm, and an applied electric field of 300 V/mm. These results elucidate how the physical mechanisms govern charge sharing in FAPbBr 3 detectors, thereby defining practical limits and optimization strategies for pixelated perovskite‐based radiation detection systems.