Optoelectronic synapse based on the Bi2O2Se/Cs3Cu2I5 heterojunction for neuromorphic computing

In this work, we report an optoelectronic synapse based on the Bi2O2Se/Cs3Cu2I5 heterojunction formed by consequently depositing Bi2O2Se and Cs3Cu2I5 thin films by chemical vapor deposition methods. The fabricated Au/Bi2O2Se/Cs3Cu2I5/Au devices exhibit the light-tunable photoresponse under visible light illumination. Synaptic functions including paired-pulse facilitation, the transition from short-term plasticity to long-term plasticity, associative learning and optical encoding, are conveniently reproduced on one single synaptic device by utilizing the light-tunable evolution of photocurrent. Furthermore, the front-end image preprocessing to enhance the accuracy and efficiency of image recognition was demonstrated based on the constructed device array (5 × 7). This indicates the potential application of Bi2O2Se/Cs3Cu2I5 optoelectronic synapses for the forthcoming neuromorphic computing.