WSe2 Monolayer: A Stable Two-Dimensional Heterostructure Material from First-Principles of Simulation Calculations

Abstract

P-N junctions or heterostructures are commonly used in the fabrication of self-driven photodetectors because they serve critical roles in influencing the electrical characteristics of two-dimensional (2D) materials. For stable 2D heterostructures, planar WSe2 monolayers have attracted a lot of interest. Using first-principles energetic and dynamic calculations, we find that the transition from the indirect band gap of WSe2 bulk phase to the direct band gap of a two-dimensional plane is caused by the formation of p-n hetero junctions. Furthermore, it affects the carrier concentration transport mode and results in a significant orbital spin coupling. There is no virtual frequency in the phonon dispersion curve across the Brillouin zone at zero pressure. The interaction of the nearest neighbour atoms causes the frequency of the two acoustic modes of the G-point to be zero, as well as the frequency of the two optical films to merge. The theoretical analysis can provide support for the transport of two-dimensional planar carriers in electronics and photonics.