Interfacial electronic states and self-formed p–n junctions in hydrogenated MoS2/SiC heterostructure

Abstract

It is difficult to generate p–n junctions in atomically thin transition metal dichalcogenides (TMDs) because of the great challenge of selective doping. First-principles calculations demonstrate that the electronic states in monolayer MoS₂ could be substantially tuned through contact with hydrogenated SiC sheets, as a result of interface-induced electronic doping. Specifically, monolayer MoS₂ exhibits metallic characteristics when put in contact with the Si termination of SiC–H (MoS₂/SiC–H), but exhibits ambipolar type polarization when in contact with the C termination of CSi–H (MoS₂/CSi–H). Furthermore, monolayer MoS₂ can be switched from p-type on H–Si terminations (MoS₂/H–SiC and MoS₂/H–SiC–H) to n-type on H–C terminations (MoS₂/H–CSi and MoS₂/H–CSi–H). Accordingly, p–n junctions can be generated in bilayer MoS₂ if a fully hydrogenated monolayer SiC is inserted between the layers. In addition, the staggered band alignment of the top and bottom monolayers of MoS₂ leads to considerable rectification of current. The results are helpful for the design of TMD based nanoelectronic devices.