Performance of the Pentagonal PdSe₂ Sheet as a Channel Material in Contact with Metal Surfaces and Graphene

Motivated by the recent synthesis of the pentagonal PdSe2 sheet [J. Am. Chem. Soc. 2017, 139, 14090], here using first-principles calculations, we have systematically carried out simulations to investigate the PdSe2 sheet’s performance as a channel material when in contact with metal surfaces and graphene. We find that the PdSe2 sheet can almost retain its pentagonal feature with small distortions when in contact with Au(111), Ag(111), Cu(111), and Pb(111) surfaces. However, it is severely distorted on the Ti(0001) surface undergoing metallization. Band structure analysis suggests that the vertical Schottky barrier disappears in all of the metal contacts. Au, Ag, Cu, Ti, and Pb are of the Schottky type contacts with barriers of 0.62, 0.87, 0.79, 0.58, and 0.76 eV in the lateral direction for electrons, whereas both monolayer and bilayer PdSe2 maintain their intrinsic properties when in contact with graphene forming a weak van der Waals interaction with no charge transfer between the two surfaces. Our study provides insights into selecting high-performance monolayer PdSe2 device evaluations based on the orbital overlap, tunneling barrier, and Schottky barrier.