Insights into Multilevel Resistive Switching in Monolayer MoS2

The advent of 2D materials has opened a plethora of opportunities in accessing ultra-scaled device dimensions for future logic and memory applications. In this work we demonstrate that a single layer of large area chemical vapor deposition-grown molybdenum disulfide (MoS2) sandwiched between two metal electrodes can be tuned to show multi-level non-volatile resistive memory states with resistance values separated by 5 orders of magnitude. The switching process is unipolar and thermochemically driven requiring significant Joule heating in the reset process. Temperature dependent electrical measurements coupled with semi-classical charge transport models suggest that that the transport in these devices varies significantly in the initial (pristine) state, high resistance state and low resistance state. In the initial state, the transport is a one-step direct tunneling (at low voltage biases) and Fowler Nordeim tunneling (at higher bias) with an effective barrier height of 0.33 eV, which closely matches the ...