Tin Doping Induced High‐Performance Solution‐Processed Ga 2 O 3 Photosensor toward Neuromorphic Visual System

Abstract Ga 2 O 3 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, Ga 2 O 3 ‐based photosensors with high responsivity and long response decay times are required for efficient NVSs. A solution‐processed doping strategy for fabrication of Ga 2 O 3 is proposed with tin foil as a dopant source. Tin‐doped Ga 2 O 3 (Ga 2 O 3 :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 Ga 2 O 3 :Sn photosensors can mimic photonic synaptic behaviors and image pre‐processing functions. NVSs based on a Ga 2 O 3 :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 Ga 2 O 3 :Sn NVSs and will facilitate developments in artificial intelligence technology.