Self-rectifying bipolar resistive switching memory based on an iron oxide and graphene oxide hybrid

Abstract

A resistive random access memory (RRAM) device with self-rectifying I–V characteristics was fabricated by inserting a silicon nitride (Si₃N₄) layer between the bottom electrode and solution-processed active material of an iron oxide–graphene oxide (FeO_x–GO) hybrid. The fabricated Au/Ni/FeO_x–GO/Si₃N₄/n⁺-Si memory device exhibited an excellent resistive switching ratio and a rectification ratio higher than 10⁴. In the Au/Ni/FeO_x–GO/Si₃N₄/n⁺-Si device, resistive switching occurs in both the FeO_x–GO and Si₃N₄ layers separately, resulting in a highly uniform and stable switching performance. The resistive switching from a high resistance state to a low resistance state in the Au/Ni/FeO_x–GO/Si₃N₄/n⁺-Si device occurs through a trap-assisted tunneling process in the Si₃N₄ layer, enabled by the FeO_x–GO layer which prevents diffusion of the migrating Ni metal into the switching nitride layer. The intrinsic self-rectifying characteristics of our memory devices arise from the asymmetric barriers for electrons tunneling into the traps of the Si₃N₄ layer which is sandwiched between the top and bottom electrodes having dissimilar work functions. Our study confirmed that integrating a suitable dielectric layer into the conventional RRAM cell is an innovative strategy to simplify the architecture and fabrication process to realize self-rectifying crossbar arrays.