γ-Ray irradiation-induced unprecedent optical, frictional and electrostatic performances on CVD-prepared monolayer WSe₂

Abstract

Kelvin probe force microscopy. Due to different environments, molecular collisions lead to an increase in the concentration of vacancy defects, which made our results different from those previously reported. The first principles calculation suggests that an increase in the selenium vacancy population is generally accompanied by a transition from a direct gap material to an indirect one. This opens up a new venue to engineer the optical, frictional and electronic properties of transition metal dichalcogenides using irradiation.