The role of intrinsic atomic defects in a Janus MoSSe/XN (X = Al, Ga) heterostructure: a first principles study

The interactions between different layers in van der Waals heterostructures have a significant impact on the electronic and optical characteristics. By utilizing the intrinsic dipole moment of Janus transition metal dichalcogenides (TMDs), it is possible to tune these interlayer interactions. We systematically investigate structural and electronic properties of Janus MoSSe monolayer/graphene-like Aluminum Nitrides (MoSSe/g-AlN) heterostructures with point defects by employing density functional theory calculations with the inclusion of the nonlocal van der Waals correction. The findings indicate that the examined heterostructures are energetically and thermodynamically stable, and their electronic structures can be readily modified by creating a heterostructure with the defects in g-AlN monolayer. This heterostructure exhibits an indirect semiconductor with the band gap of 1.627 eV which is in the visible infrared region. It can be of interest for photovoltaic applications. When a single N atom or Al atom is removed from a monolayer of g-AlN in the heterostructure, creating vacancy defects, the material exhibits similar electronic band structures with localized states within the band gap which can be used for deliberately tailoring the electronic properties of the MoSSe/g-AlN heterostructure. These tunable results can offer exciting opportunities for designing nanoelectronics devices based on MoSSe/g-AlN heterojunctions.