Negative differential resistance induced by sulfur vacancies in monolayer MoS2 transistors

Extensive research has been conducted on the negative differential resistance (NDR) behavior in various electronic applications. Theoretical simulations suggest that defects in monolayer 2D materials could impact the NDR phenomenon. In this study, we experimentally validated this theoretical prediction using straightforward fabrication methods on monolayer MoS2. To create MoS2 transistors with a specific amount of sulfur vacancy, we employed techniques such as KOH solution treatment, electron beam irradiation, and chemical vapor deposition (CVD) using low sulfur supply. Through comprehensive analysis of the devices’ electrical characteristics and spectroscopic examination, we successfully observed the NDR in the defective monolayer MoS2 field-effect transistors (FETs) with approximately 5% sulfur vacancy, as confirmed by X-ray photoelectron spectroscopy (XPS). Moreover, this NDR effect remains stable and can be controlled by the gate electric field or light intensity at room temperature. This discovery suggests that the NDR effect in monolayer MoS2 transistors holds promising potential for future electronic applications.