Electron-beam-irradiated rhenium disulfide memristors with low variability for neuromorphic computing

Abstract

State-of-the-art memristors are mostly formed by vertical metal-insulator-metal (MIM) structure, which rely on the formation of conductive filaments for resistive switching (RS). However, owing to the stochastic formation of filament, the set/reset voltage of vertical MIM memristors are difficult to control, which results in poor temporal and spatial switching uniformity. Here, a two-terminal lateral memristor based on electron beam irradiated rhenium disulfide (ReS2) is realized, which unveil a unique resistive switching mechanism based on Schottky barrier height (SBH) modulation. The devices exhibit a forming-free, stable gradual RS characteristic, and simultaneously achieve a small transition voltage variation during positive and negative sweeps (6.3%/5.3%). The RS is attributed to the motion of sulfur vacancies induced by voltage bias in the device, which modulates the ReS2/metal SBH. The gradual SBH modulation stabilizes the temporal variation in contrast to the abrupt RS in MIM-based memristors. Moreover, the emulation of long-term synaptic plasticity of biological synapses is demonstrated using the device, manifesting its potential as artificial synapse for energy-efficient neuromorphic computing applications.