Top-gate engineering of field-effect transistors based on single layers of MoS2 and graphene

Abstract

Field-effect transistors (FETs) were fabricated with use of vertical heterostructures of graphene and MoS2 monolayers with top-gate and back-gate configurations. Nanodiamonds/poly(vinylidene difluoride) (1:1) and SiO2 were used as the top-gate and back-gate dielectric, respectively. The novel top-gate electrode and gate dielectric assembly consisting of polyaniline and nanodiamonds/poly(vinylidene difluoride) were synthesized by a chemical oxidative polymerization approach. Our MoS2 FETs showed a high linear mobility of approximately 212 cm2/V s and a high on/off current ratio of up to 107 at 10 V for top-gated FETs, which is much greater than for conventional back-gated FETs. The devices were stable under elevated temperatures up to 100 °C, with a decrease in the on/off current ratio. The devices showed good stability without any additional encapsulation after an elapsed time of 10 days, as the results on the first and tenth days were identical. This work will pave the way for the design of high-performance FETs for applications in electronics and optoelectronics.