Engineering p-n junctions in grapbene/molybdenum disulfide heterostructures

Engineering p-n junctions in two-dimensional (2D) materials, specifically transition metal dichalcogenides (TMDs), entails choosing the right combination of materials in order to form the appropriate alignment of bands. A bi-polar junction having a heterogenous combinations of materials has traditionally been used for several applications such as rectifiers, photovoltaics, etc, which require separation of charge carriers. Various researchers have studied the synthesis and properties of p-n junctions in TMD-TMD heterostructures, like MoS ₂ /WSe ₂ , Mos ₂ /ws ₂ , etc. ¹ In this work, we show the formation of a low resistance p-n junction between graphene and molybdenum disulfide (MOS ₂ ), which harnesses the high thermal and electronic mobility of graphene, which semiconducting TMDs do not provide. Our work employs epitaxial graphene (EG) on silicon carbide substrates, which has the unique property of doping modulation using hydrogen intercalation. ^2,3 This has not been exploited previously to construct devices using graphene-based heterostructures.