Ohmic/Schottky barrier engineering in metal/SnP3 heterostructures

Abstract

Abstract Using the density functional theory, we systemically investigate the structural and electronic properties of SnP3 monolayer and bilayer adsorbed on metallic substrates, including graphene (Gr), Cu(111), and Ni(111). Our main findings indicate that the SnP3 layers develop a stack with graphene through the van der Waals interaction, in contrast to strongly chemical binding, observed with the transition metals, such as Cu(111) and Ni(111). Upon building Gr/SnP3 heterostructures, we found that the Dirac cone in graphene is well preserved, forming an n-type Schottky contact with a small Schottky Barrier Height (SBH), which in turn is very sensitive to the external conditions. By reducing the interfacial distance between Gr and SnP3 layers, a Schottky contact to a p-type ohmic contact transition can be effectively realized, while an n-type ohmic contact can be generated by applying a finite external electrical field. By contrast, strong interaction with Ni(111) and Cu(111) seriously disrupts the electronic structure of SnP3 layers, that can be avoided by introducing graphene or h-BN as buffer layers between SnP3 layers and transition metal substrates. Furthermore, increasing the layer number of the inserted Gr or BN, up to bilayers, is found to be enough to achieve an n-type ohmic contact. These findings provide useful insights for designing novel SnP3-based field effect transistors (FETs) devices with n- or p-type ohmic contacts.