Vacancy and strain effects on electronic structures of monolayer hexagonal 1T-phase pdSe2

Abstract

Two-dimensional transition metal dichalcogenides (TMDs) such as MoS2 and WS2 have traditionally been used, but Group-10 TMDs have recently attracted attention due to their small and tunable band gap and high mobility. This paper investigates the impact of vacancy and strain on the structure of hexagonal single-layer PdSe2 using density functional theory (DFT) calculations. The sublayers can introduce strain into the structure when building these 2D surfaces. Structures with chalcogen vacancies are more stable than those with metallic vacancies. When Se atoms are removed, the band gap disappears, and the semiconductor phase changes from semiconductor to conductor. The band gap can be recreated by applying a suitable percentage of strain using the vacancy mode. The work function (WF) was also calculated. WF decreases with compressive strain but increases with Se removal and tensile strain.