Transition from Schottky-to-Ohmic contacts in 1T VSe2-based van der Waals heterojunctions: Stacking and strain effects

Abstract For its ultra-high conductivity, room temperature ferromagnetic, and robust stability, monolayer 1T VSe2 acts as a promising two-dimensional (2D) material for new spintronics device. However, Ohmic contact with semiconductor is a desirable property for high-performance devices due to the obstruction of strong Fermi level pinning effect at the Schottky interface. Herein, we employ density functional theory to explore a series of VSe2-based van der Waals heterojunctions, in which Ohmic contact is only found in the VSe2-multilayer MoSSe junctions due to the destruction of depletion region and the increase of electron tunneling probability. Moreover, applying appropriate biaxial tensile stress can also lead to the transition from Schottky-to-Ohmic contact in the VSe2-based metal-semiconductor junctions. Our results provide an avenue for the design of future 2D VSe2-based electronics.