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

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.