Tin Doping Induced High‐Performance Solution‐Processed Ga₂O₃ Photosensor toward Neuromorphic Visual System

Abstract Ga₂O₃ is an emerging wide‐bandgap semiconductor with high deep ultraviolet absorption, tunable persistent photoconductivity, and excellent stability toward electric fields, making it a promising component for neuromorphic visual systems (NVSs). However, Ga₂O₃‐based photosensors with high responsivity and long response decay times are required for efficient NVSs. A solution‐processed doping strategy for fabrication of Ga₂O₃ is proposed with tin foil as a dopant source. Tin‐doped Ga₂O₃ (Ga₂O₃:Sn) photosensors are obtained with ultrahigh responsivity and extremely long response decay times. These behaviors are attributed to substitutional tin and oxygen vacancies that modulate defect‐related hole trapping. High‐performance Ga₂O₃:Sn photosensors can mimic photonic synaptic behaviors and image pre‐processing functions. NVSs based on a Ga₂O₃:Sn photonic synapse array perform pattern recognition with an accuracy of 97.3% under an unprecedented low‐light pulse stimuli of 0.5 µW cm⁻². This work provides a low‐cost solution‐processed approach to ultrasensitive Ga₂O₃:Sn NVSs and will facilitate developments in artificial intelligence technology.