First-Principles Calculations on Janus MoSSe/Graphene van der Waals Heterostructures: Implications for Electronic Devices

In the preparation and characterization of experiments, it is easy to introduce miscellaneous items and defects that often have impacts on the physical properties of materials. In the MoSSe monolayer, Mo, S, Se, and S–Se vacancy defects all reduce the band gap, and the static potential difference and magnetic properties also change accordingly. On this basis, S and Se single-vacancy defects are introduced into MoSSe/graphene (G) heterostructures to compare the effect of the electronic properties in two different stacking modes. The Schottky barrier is greatly reduced by either S or Se single-vacancy defects in the SMoSe/G stacking mode. In the SeMoS/G stacking mode, the generation of vacancy defects leads to p-type doping of graphene, and the graphene carrier density can reach 0.900 × 1013 and 1.117 × 1013 cm–2 for S and Se vacancy defects, respectively. Meanwhile, the biaxial strain applied to the defective heterostructures can effectively modulate the carrier density of graphene. Our results may provide some trending guidance in tunable nanoelectronic devices based on two-dimensional Janus/G heterostructure materials.