Insight of the high switching window and data retention in lead-free 2D layered double perovskite resistive memory device

Abstract

Lead-free robust halides double perovskites (DPs) are evolving as the key materials for the multi-functional resistive memory application. Herein, we aimed to enhance the switching window, i.e., current On/Off ratio by the cutting edge dimensional reduction of the three dimensional Cs2AgBiBr6 DP into two dimensional (2D) BA4AgBiBr8 (BA = butylammonium) DP and studied the insight of their resistive switching anomaly. We affirmed that the improved On/Off ratio (∼103 to ∼106) is attributed to the restricted charge transport in the high resistance state (HRS) of the BA4AgBiBr8 based switching device. The low HRS current can be ascribed to the synergies of higher Schottky barrier at the Au/BA4AgBiBr8 junction and higher thermal activation energy in the layered DP. Owing to the higher switching window in the 2D DP device, reproducible endurance (tested up to 500 cycles) and retentivity (tested up to 104 s) of the resistance states establish that the high On/Off ratio could be retained without significant deviation. The resistive memory behavior could be hypothesized by the charge trapping phenomenon in the BA4AgBiBr8 DP, as the charge retention was persisted over 60 min as evident from surface potential images of Kelvin probe force microscopy.