Electrografted Fluorinated Organic Ultrathin Film as Efficient Gate Dielectric in MoS2 Transistors

Abstract

Dielectric films with nanometer thickness play a central role in the performances of field effect transistors (FETs). In this article, a new class of organic gate dielectric based on the electrochemical grafting of diazonium salts on metallic electrodes is investigated. The versatile diazonium salt strategy is a local and room-temperature process that provides robustness and performances. Moreover, this process produces ultrathin (4–8 nm) and smooth films. To prove their efficiency as gate dielectric, they were integrated in MoS2–FETs gate stacks. The devices display excellent switching behavior for reduced gate bias swing (down to 1 V) and suppressed hysteresis thanks to the highly hydrophobic nature of the fluorinated grafted film. Furthermore, the devices exhibit steep subthreshold slopes (as low as 110 mV/decade), demonstrating excellent gate coupling.