Multilevel resistive switching memory based on GO/MoS2/GO stack

Abstract

Resistive switching memory is one of the promising candidates for the next generation non-volatile memory due to its simple fabrication process as well as outstanding memory performance including fast switching speed and low power consumption [1-3]. As a strategy for maximizing information storage density, the multilevel cell (MLC) devices have been extensively studied in the past decades such that the MLCs of resistive switching memory has been reported from various materials, such as polymers and binary metal oxides [4-6]. However, there only exists few study of the MLC operation based on only two dimensional (2D) materials.

We report a multilevel resistive switching memory based on 2D materials of graphene oxide (GO) thin film and MoS2 nanasheets. MoS2 nanosheets, exfoliated by Li intercalation process, were readily embedded between two GO thin films using a simple spin-coating process. The GO/MoS2/GO stacks provide the significant On/Off current ratio increase from 102 to 104 with the addition of MoS2 nanosheet, and the excellent multilevel non-volatile memory performance including at least 104 s retention time, 102 endurance cycle without severe degradation, and four multiple resistance states. Furthermore, we confirmed the resistive switching mechanism that trapped space charges in MoS2 deep trap sites determine the number of resistance states, which could be modulated by electrical bias. This work proposes that MoS2 nanosheets could be utilized as good charge storage materials giving MLC operation in GO-based memristors.