Photo‐synaptic Memristor Devices from Solution‐processed Ga₂O₃ Thin Films

Abstract Hardware integration with biological synaptic function is the key to realizing brain‐like computing. Resistive Random Access Memory (RRAM), with a similar structure to biological synapses, are important candidate for the simulation of biological synaptic function. In this work, Ga 2 O 3 film as a functional layer of RRAM is prepared by the solution method, and an RRAM‐based photo‐synaptic device with an Ag/Ga 2 O 3 /Si structure is constructed subsequently. The device exhibits excellent bipolar resistive switching characteristics, with the merits of a large storage window and long retention time. Furthermore, the devices generated excitatory postsynaptic currents (EPSC) and paired‐pulse facilitation (PPF) behaviors under light pulse stimulation, enabling the simulation of synaptic plasticity. The transformation of synaptic behavior from short‐term memory (STM) to long‐term memory (LTM) is achieved by observing the spike‐duration dependent plasticity (SDDP), spike‐intensity dependent plasticity (SIDP), spike‐number dependent plasticity (SNDP) and spike‐rate dependent plasticity (SRDP) characteristics of photonic synapses under different conditions. The device also simulates the process of successive “learning‐forgotten‐remembering”, revealing that RRAM‐based photonic synapses have great potential in the fields of artificial visual perception and memory storage.