Resistive switching in 2D bismuth oxyhalide nanosheets for nonvolatile memory and emulation of leaky integrate-and-fire functions

The resistive switching (RS) behaviors have been widely studied in a large number of two-dimensional (2D) materials. Bismuth oxyhalides have emerged as a typical ternary 2D layered material recently. However, the studies focusing on the RS behaviors in 2D bismuth oxyhalides are still limited. Herein, the RS behaviors in 2D BiOX (X = Cl, Br and Cl + Br) nanosheets have been systematically studied. 2D BiOX nanosheets are exfoliated from their bulk materials which are synthesized by a hydrothermal method. Vertical memristors with Pt/BiOX/Pt sandwiched structures have been fabricated for RS measurements. Among them, 2D BiOCI nanosheet has no RS behaviors. BiOBr nanosheet demonstrates non-volatile bipolar RS behaviors with a large ON/OFF ratio (similar to 10(5)), long time retention (10(4) s) and good endurance (280 cycles) as well as good environmental stability, suggesting potential applications in nonvolatile memory. Furthermore, BiOBr0.7Cl0.3 nanosheet shows volatile threshold switching (TS) behaviors with the ON/OFF ratio up to 10(5). The device with TS behaviors can be utilized to emulate the leaky integrate-and-fire (LIF) functions in biological synapses. This work demonstrates a new material with non-volatile or volatile RS behaviors, providing a new TS device for emulation of LIF activity. (C) 2022 The Authors. Published by Elsevier Ltd.

Automated summary

In this study, the resistive switching behaviors in 2D BiOX nanosheets were systematically investigated, with BiOBr nanosheet demonstrating non-volatile bipolar RS behaviors and BiOBr0.7Cl0.3 nanosheet showing volatile threshold switching behaviors. These findings provide a new material foundation for research on novel memory devices and biomimetic synapses.