MoS2 transistors have been electrically characterized and analyzed in terms of their vulnerability to short channel effects and their response to various environments. We find that the electrical performance of MoS2 flakes is governed by an unexpected dependence on the effective body thickness of the devices that in turn depends on the amount of intercalated water molecules that exist in the layered structure. In particular, a decrease in effective body thickness is observed in air compared to the "water-free" scenario. Moreover, we find that the doping stage of a MoS2 field-effect transistor (FET) is p-type despite the appearance of electron conduction, and the amount of p-doping is higher in air than in vacuum. Most importantly, our results indicate that device characteristics of MoS2 can be substantially impacted by tuning the device electrostatics. This can be accomplished by controlling the effectively active body thickness of the MoS2 FET employing intercalation and engineering of the effective barrier between individual MoS2 layers.
Keywords: 2D-layered materials; MoS2; dielectric constant; short channel effects; ultrathin body devices.