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.