Tunable Band Structures of Heterostructured Bilayers with Transition-Metal Dichalcogenide and MXene Monolayer

Forming bilayer or multilayer heterostructures via interlayer van der Waals interactions is a superior preparation strategy for two-dimensional heterojunctions. In this work, by employing density functional theory computations, we investigated heterostructured bilayers of transition-metal dichalcogenides (TMDs) (including MoS2, WS2, MoSe2, and WSe2) and MXene (exemplified by Sc2CF2) monolayer. All TMD and Sc2CF2 materials are hexagonal with little mismatch. Compared with separate TMD and Sc2CF2 monolayers, TMD–Sc2CF2 bilayers can be tuned to indirect semiconductors with the band gaps of 0.13–1.18 eV; more importantly, they are type-II heterostructures with the valence band maximum and conduction band minimum located at Sc2CF2 and TMDs, respectively. Stretching or compressing would reduce or enlarge the band gaps of the heterostructures, respectively. The tunable band structures make TMD–Sc2CF2 bilayers pomising candidates for electronic device applications.