Journal Article

Bilayers of transition metal dichalcogenides: Different stackings and heterostructures

Terrones, Humberto, Terrones, Mauricio

2014

Overview

Besides graphene and hexagonal boron nitride, transition metal dichalcogenides (TMDs) also exhibit a layered structure in which the layers weakly interact via van der Waals forces. Semiconducting TMDs in bulk are indirect band gap materials. However, an isolated sheet exhibits a direct gap. This particular behavior makes them very attractive in terms of optical properties. Moreover, NbS2 and NbSe2 in bulk and their monolayers are metallic. Density functional theory calculations were carried out to study different TMD bilayer systems. First, different bilayer geometries with different stackings were considered. It was found that the indirect and direct band gaps compete; however, the indirect band gap always dominates. Surprisingly, bilayer heterostructures of different TMDs have been found to possess direct band gaps. Finally, heterobilayers composed of one metallic monolayer and a semiconducting layer are predicted as novel metallic van der Waals solids that might find applications in new two-dimensional nanodevices.

• Publisher: Cambridge University Press,Springer International Publishing,Springer Nature B.V
• Subject: Applied and Technical Physics / Biomaterials / Density functional theory / Electrons / Energy gaps (solid state) / Graphene / Heterostructures / Inorganic Chemistry / Invited Paper / Invited Papers / Materials Engineering / Materials research / Materials Science / Monolayers / Nanotechnology / Nanotubes / Optical properties / Semiconductor research / Stacking / Studies / Sulfur / Thin films / Transition metals / Van der Waals forces