γ‐Ga 2 O 3 Quantum Dots/Graphene Heterostructure Enabling Bidirectional All‐Optical Artificial Synapses for Ultraviolet Motion Recognition

ABSTRACT Artificial intelligence vision systems require the seamless integration of sensing, memory, and computing to overcome the latency and power consumption bottlenecks of traditional von Neumann architectures. While optoelectronic memristors offer a promising solution, most existing devices rely on hybrid optical‐electrical modulation, limiting their efficiency and speed. Here, we present an all optical‐modulated artificial synapse based on a γ ‐Ga 2 O 3 quantum dots/graphene heterostructure. This device leverages the reversible, wavelength‐selective oxygen adsorption/desorption of the γ ‐Ga 2 O 3 QDs. Specifically, 365 nm ultraviolet light triggers oxygen desorption, reducing graphene conductivity to mimic inhibitory synaptic behavior, while 690 nm red light promotes oxygen re‐adsorption, enhancing conductivity to simulate excitatory behavior. In situ Kelvin probe force microscopy and environmental controls experiments confirm this mechanism is driven by interfacial charge transfer modulated by surface oxygen dynamics. The device emulates essential synaptic plasticities, including paired‐pulse facilitation/depression and the transition from short‐term to long‐term plasticity. Furthermore, by leveraging the light‐induced conductance changes of synaptic devices, we demonstrate bio‐inspired visual preprocessing capabilities such as retinal‐mimetic edge detection and bionic motion tracking within a foraging scene simulation. This work offers a feasible strategy for developing power‐efficient, all‐optical‐controlled neuromorphic vision prototypes at the device level, bridging surface defect engineering with advanced visual perception.