Novel heterostructures by stacking layered molybdenum disulfides and nitrides for solar energy conversion

Two-dimensional graphene-like materials have attracted considerable attention for the further development of nanoscale devices. In this work, the structural, electronic and optical properties of freestanding, graphene-like nitrides XN (X = B, Al and Ga) are studied by density functional calculations with the inclusion of the nonlocal van der Waals correction. The results show that all the studied nitrides are thermodynamically stable and their electronic structures can be easily tuned by forming the heterostructure with MoS2 monolayer. Although GaN and AlN monolayers retain the indirect band gap of bulk, MoS2-AlN and MoS2-GaN heterostructures have suitable direct gaps, complete electron-hole separation and fascinating visible light adsorption, which is promising for solar energy applications. Moreover, the MoS2-AlN heterostructure is a good candidate for enhanced photocatalytic activity of hydrogen generation from water.