Theoretical characterization of strain and interfacial electronic effects in donor-acceptor bilayers of 2D transition metal dichalcogenides

Two-dimensional (2D) materials and their van der Waals (vdW) stacked hetero-structures are promising candidates for highly efficient (opto)-electronic applications. The performance of vdW heterostructures in devices strongly depend on electronic processes at their interfaces. Here, using first–principle calculations, we have explored systematically the structural and electronic properties of two-dimensional transition metal dichalcogenide (TMDs) monolayers and the way these properties are affected when building a bilayer. We focus on MoS2-based bilayers, including MoS2/MoS2, WS2/MoS2, MoSe2/MoS2 and WSe2/MoS2 structures. The impact of vacancies on the interlayer interactions is also investigated. The main finding of our calculations is that changes in the properties of 2D monolayers upon building stack do occur and are driven by both strain effects and interfacial electronic processes.