White light-modulated bipolar resistive switching characteristics of Cu/MoS2 NRs/Pt MIM structure

Abstract

The present work explores the white light controlled resistive switching functionality of MoS2 nanorods (NRs) by fabricating a metal-insulator-metal stack configuration. The Cu/MoS2 NRs/Pt/Si device demonstrates the reproducible two-state bipolar resistive switching characteristics under both dark and light environments. In the dark condition, the resistive switching behavior of the NR device could be attributed to the metallic path formation/rupture between top and bottom electrodes. Whereas the applied white light causes the lowering of SET and RESET voltages by inducing conducting path formation/rupture via electron trapping/detrapping in sulfur vacancies across the MoS2 NRs. The formation of a conducting path under dark and light illumination conditions is well explained by proposing a conceptual model and analyzing the resistance vs temperature measurements. It is observed that the white light acts as an external tool to modulate the resistive switching behavior of the fabricated NR device. The correlation between the applied light intensity and the SET voltage is also demonstrated. The NR structure of the MoS2 device provides good endurance of 1500 cycles and a long retention time of 103 s at room temperature under light illumination because of straight conducting path formation through NRs. These results demonstrate that the optically active MoS2 NR based devices have potential for next generation tunable nonvolatile resistive random access memory applications with additional functionality such as photosensors and optoelectronic switches.