An Optical Artificial Synapse Based on Single‐Crystal Se‐Vacancy Bi2O2Se

Abstract The optical synaptic device is a novel nonvolatile memory device that combines optical sensing function with synaptic plasticity to simulate the basic biomimetic behaviors of the human visual system. It shows a great potential application in artificial vision. However, most of the current optical synaptic devices are either structurally special or complex, which are quite difficult to prepare especially for mass production. In this work, a submillimeter single‐crystal Bi 2 O 2 Se flake with selenium vacancies (Bi 2 O 2 Se‐V Se ) grown by physical vapor deposition is presented. Upon the Bi 2 O 2 Se‐V Se flake, an optical synaptic device is designed with the persistent photoconductivity (PPC) effect induced by selenium vacancies. The device can simulate the biological synapses with an obvious synaptic plasticity. Moreover, an artificial vision system consisting of a 3 × 4 array of optical synaptic devices has been fabricated. The intensity of the image pattern can keep at a high memory level of 54.64% and 19.31% for 532 and 1060 nm waiting for 400 s after illumination of 100 s, which demonstrates the devices exhibit excellent image sensing, learning, and memory storage. This work opens up a new route for fabricating the optical synaptic device with a simple structure and provides new ideas for studying artificial vision systems.