Monolayer SnS2 Schottky barrier field effect transistors: effects of electrodes.

Abstract

Achieving Ohmic contacts with low resistance is quite desirable for two-dimensional (2D) Schottky barrier field effect transistors (SBFETs). We verify the electrode effect on monolayer (ML) SnS2 SBFETs using ab initio calculations. With the aforeselected ML electrodes from matching lattices and work functions, we obtain n-type Ohmic contacts or quasi-Ohmic contacts to ML SnS2 with ML 1T-NbTe2, Sc2NF2, Mo2NF2, Nb2CF2, and graphene electrodes. The n-type ML SnS2 SBFET with the Ohmic-contact 1T-NbTe2 electrode exhibits remarkably better device performance than that with a Schottky-contact 2H-NbTe2 electrode, and their on-state currents of 629/1048 μA μm-1, delay times of 0.236/0.169 ps, and power dissipations of 0.074/0.089 fJ μm-1 exceed the International Roadmap for Devices and Systems targets for low-power/high-performance application. This study reports on Ohmic-contact electrodes for n-type ML SnS2 SBFETs and can give hints for future theoretical and experimental studies on 2D SBFETs.