Artificial visual perception neural system using a solution-processable MoS_(2)-based in-memory light sensor

摘要

Optoelectronic devices are advantageous in in-memory light sensing for visual information processing,recognition,and storage in an energy-efficient manner.Recently,in-memory light sensors have been proposed to improve the energy,area,and time efficiencies of neuromorphic computing systems.This study is primarily focused on the development of a single sensing-storage-processing node based on a two-terminal solution-processable MoS2 metal-oxide-semiconductor(MOS)charge-trapping memory structure—the basic structure for charge-coupled devices(CCD)—and showing its suitability for in-memory light sensing and artificial visual perception.The memory window of the device increased from 2.8 V to more than 6V when the device was irradiated with optical lights of different wavelengths during the program operation.Furthermore,the charge retention capability of the device at a high temperature(100 ℃)was enhanced from 36 to 64%when exposed to a light wavelength of 400 nm.The larger shift in the threshold voltage with an increasing operating voltage confirmed that more charges were trapped at the Al_(2)O_(3)/MoS_(2) interface and in the MoS_(2) layer.A small convolutional neural network was proposed to measure the optical sensing and electrical programming abilities of the device.The array simulation received optical images transmitted using a blue light wavelength and performed inference computation to process and recognize the images with 91%accuracy.This study is a significant step toward the development of optoelectronic MOS memory devices for neuromorphic visual perception,adaptive parallel processing networks for in-memory light sensing,and smart CCD cameras with artificial visual perception capabilities.