All‐In‐One Sensing‐Memory‐Computing System Based on a Self‐Powered MoS 2 P‐N Homojunction Transistor

ABSTRACT Transition metal chalcogenides are promising for integrated sensing‐memory‐computing optoelectronics, owing to their atomic‐scale thickness and outstanding electrostatic control. However, the fast charge dynamics required for sensing conflict with the long charge retention needed for storage and synapses, hindering their functional integration in a single device. This work demonstrates a multifunctional MoS 2 P‐N homojunction ambipolar transistor, formed by vertically stacking intrinsic MoS 2 with uniform P‐type MoS 2‐x O δ prepared by ultraviolet‐ozone photochemical doping. This type‐II homojunction exhibits gate‐tunable ambipolarity, enabled by oxygen‐doping‐modulated band structure and interfacial charge transfer. Kelvin probe force microscope (KPFM) measurement directly corroborate the built‐in electric field and efficient photogenerated charge separation in the junction region, confirming its type‐II band alignment and self‐powered operation. Simply by switching the gate polarity, the device can be reversibly reconfigured. Under negative gate bias, it acts as a fast, sensitive self‐powered photodetector. Under positive gate bias, it exhibits self‐powered persistent photoconductivity, nonvolatile multilevel memory, and synaptic plasticity. Based on these reconfigurable functions, the platform integrates on‐chip high‐contrast single‐pixel imaging, long‐term optical storage, and an optical front‐end bionic visual neural network. This work provides a high‐performance compact, low‐power platform for brain‐inspired perception and computing from 2D materials defect engineering perspective.