Two dimensional MoS₂/graphene p-n heterojunction diode: Fabrication and electronic characteristics

Molybdenum disulfide (MoS₂) films are currently the most potential semiconductor materials of the two-dimensional nano-material heterojunction. Few-layer MoS₂ is an n-type semiconductor that has good mechanical strength, high carrier mobility, and has similar thickness as graphene. Graphene is presently the thinnest two-dimensional material with good thermal conductivity and high carrier mobility. The graphene Fermi level can be precisely controlled using the oxygen adsorption. Therefore, graphene can be tuned from zero-gap to p-type semiconductor material using the amount of adsorbed oxygen. In this study we combine few-layer MoS₂ and graphene to produce a heterojunction and exhaustively study the interface properties for heterojunction diode application. According to the results, the MoS₂ band-gap increases with decreasing thickness. The I–V characteristics of the MoS₂/Graphene p-n junction diodes can be precisely tuned by adjusting different thicknesses of the MoS₂ films. By applying our fabricating method, MoS₂/Graphene heterojunction diode can be easily constructed and have potential to different applications. - Highlights: • We controlled the layer thickness of MoS₂ by different exfoliation times. • We presented Raman scattering of MoS₂ and define their layers number. • The few-layer MoS₂/graphene pn junction diode was synthesized. • We measured the device current and voltage characteristics. • The built-in potential barrier could be adjusted by controlling MoS₂ thicknesses.