Electronic properties and tunable Schottky barrier of non-Janus MoSSe/graphene heterostructures

We investigate the stability and electronic properties of van der Waals junctions composed with graphene and non-Janus MoSSe in comparison with graphene/Janus MoSSe configuration, and furthermore explore its Schottky barrier as well as the effect of external electric field. Based on first-principles calculations, we compare the interlayer distance and binding energy between them. It is found that with the adhesion of graphene, the less-stable Janus MoSSe becomes the most stable configuration. The graphene/non-Janus MoSSe configuration has the minimum interlayer distance, and the weak vdW interactions indicates the preservation of unique electronic properties in both two materials. An n-type Schottky contact with the Schottky barrier height (SBH) of 0.38 eV is formed at the equilibrium state for graphene/non-Janus MoSSe, while the n-type SBH for two configurations of graphene/Janus MoSSe is 0.67 and 0.10 eV, respectively. With the application of an external electric field perpendicularly to the surface, not only the Schottky barrier height but also the transition of n-type and p-type Schottky contacts as well as Ohmic contacts can be modulated within a relatively small electric field strength. This property distinguishes graphene/non-Janus MoSSe from graphene/Janus MoSSe configuration, and provides great potential for applications in optoelectronic and nanoelectronic and devices.