3D Microstructured Inorganic Perovskite Materials for Thermal Neutron Detection

Abstract A combination of novel techniques such as a solvent‐free thin‐film deposition, perovskite patterning, and ¹⁰B back‐fill technique enables the high neutron detection efficiency in a perovskite‐based microstructured thermal neutron detector. High‐efficiency cesium lead bromide (CsPbBr₃) perovskite‐based microstructured detectors are demonstrated here. Trenches up to 10 µm deep are etched into the CsPbBr₃ thin films using a novel dry etching process involving a combination of HBr and Ar plasma. The microstructured diodes are then backfilled with isotopically enriched boron as neutron conversion material via a sedimentation process to preserve the perovskite integrity. The fabricated microstructured CsPbBr₃ thermal neutron detectors show an efficiency of 4.3%. This represents >1.2x efficiency improvement over planar silicon (3.5%) and >2x efficiency improvement over planar CsPbBr₃ (2.1%) detectors, respectively. More importantly, gamma‐ray discrimination of 10⁷ is measured in CsPbBr₃‐based microstructured neutron detectors.