摘要
Resistive random-access memory (RRAM) is a promising technology for nonvolatile applications and neuromorphic computing. 2D bismuth oxyselenide (Bi2O2Se) exhibits high air stability, carrier mobility, and process compatibility. Moreover, Bi2O2Se naturally oxidizes into a high-kappa insulating oxide, Bi2O5Se, making it an ideal candidate for fabricating a dielectric layer in RRAM devices with tunable resistive properties. In this study, RRAM devices based on Bi2O2Se/Bi2O5Se bilayer dielectric thin films were epitaxially grown on (001) Nb-doped SrTiO3 substrates. The devices exhibited an exceptional nonvolatile performance, including an endurance of 3 & times; 106 pulse cycles, retention exceeding 104 s, and stable multilevel resistance states. Additionally, the synaptic-like behavior was explored by applying pulses to the devices. High-resolution in situ transmission electron microscopy and aberration-corrected scanning transmission electron microscopy were used to examine the bilayer structural evolution before and after electric-field application. The electric-field-driven oxidation of Bi2O2Se was demonstrated, and a new oxygen-deficient phase was explored during switching. These results established a resistance-switching mechanism in the Bi2O2Se/Bi2O5Se platform for fast and reliable RRAM and neuromorphic operations.