Ab-Initio and experimental study of the electronic and optical properties of layered 2D molybdenum disulphide.

Abstract

Molybdenum disulphide (MoS2) in its two-dimensional (2D) mono-to few layers is applied in numerous photonic applications owing to its wide bandgap. In this work, the electronic and optical properties of monolayer MoS2 were successfully investigated by ab initio study through density functional theory (DFT) calculation and experimental work. A 2D monolayer MoS2 model was simulated using CASTEP in the framework of plane-wave pseudopotential. The simulated bandgap is 1.7 eV which is interestingly close to those determined bandgap of MoS2 prepared through the liquid-phase exfoliation method. This confirmed the successful formation of 2D layered MoS2 in the proposed fabrication process. The MoS2 model also predict well the experimentally derived absorption range which has a significant peak at around ~600 nm wavelength ascribed to the excitonic property.