Fully Optical in Operando Investigation of Ambient Condition Electrical Switching in MoS₂ Nanodevices

Abstract

MoS₂ nanoswitches have shown superb ultra-low switching energies without excessive leakage currents. However, the debate about the origin and volatility of electrical switching is unresolved due to the lack of adequate nano-imaging of devices in operando. Here, we combine three optical techniques to perform the first non-invasive in situ characterization of nanosized MoS₂ devices. Our study reveals volatile threshold resistive switching due to the intercalation of metallic atoms from electrodes directly between Mo and S atoms, without the assistance of sulfur vacancies. We observe a "semi-memristive" effect driven by an organic adlayer adjacent to MoS₂, which suggests that non-volatility can be achieved by careful interface engineering. Our findings provide a crucial understanding of nano-process in vertically biased MoS₂ nanosheets, which opens new routes to conscious engineering and optimization of 2D electronics.