In this article, first, we show that by contact work function engineering, electrostatic doping and proper scaling of both the oxide thickness and the flake thickness, high performance p- and n-type WSe2 field effect transistors (FETs) can be realized. We report record high drive current of 98 μA/μm for the electron conduction and 110 μA/μm for the hole conduction in Schottky barrier WSe2 FETs. Then, we combine high performance WSe2 PFET with WSe2 NFET in double gated transistor geometry to demonstrate a fully complementary logic inverter. We also show that by adjusting the threshold voltages for the NFET and the PFET, the gain and the noise margin of the inverter can be significantly enhanced. The maximum gain of our chemical doping free WSe2 inverter was found to be ∼25 and the noise margin was close to its ideal value of ∼2.5 V for a supply voltage of VDD = 5.0 V.
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It is important to mention here that the use of h-BN as the insulating substrate might improve the electrostatic gating and the mobility of the WSe2 FETs as has been observed for graphene.20 This could potentially lead to even higher gain for the transistor.
