Ion migration in monolayer MoS2 memristors

Abstract

Memristors hold great promise as building blocks for future computing architectures where memory andlogic are combined at the hardware level. However, scaling down the dimensions of memristive devices has been limited by high leakage currents, thus inhibiting further progress. Recent studies have demon-strated memristors with monolayers of MoS2 and large high-to-low resistance ratios. Defects combined with metallic ion migrations are often seen as a possible explanation for this behavior. A detailed under-standing of the switching mechanisms, in particular the role of metal ion diffusion into vacancy sites and crystal defects, remains elusive. Here we investigate how defect densities affect the performance of mono-layer MoS2 memristors. We experimentally demonstrate that the resistive switching ratio becomes largerif the defect density in MoS2 is increased. Furthermore, by means ofab initioquantum transport simulations, we reveal the existence of an optimum range of defect densities and explore the theoretical limits of monolayer MoS2 memristors. Our results highlight the importance of defect engineering and control in transition metal dichalcogenides memristors.