Manipulation of contact type in MoSSe/Ti3C2 heterostructures via the functionalization of chalcogens and halogens

In the light of metallic characters and high conductivity, the newly constructed MXenes show promise as contact electrodes. However, the pristine MXenes often destroy the band dispersion of the 2D semiconductors, reflecting that they are unsuitable electrode materials for prevalent 2D semiconductors. Whether the functionalized MXenes are ideal electrode materials is worthy of being discussed. In this work, we construct MoSSe/Ti3C2 van der Waals (vdW) heterostructures and investigate the influence of functional chalcogens (O, S, Se, Te) and halogens (F, Cl, Br, I) on the electric contact type. We find that the strong interfacial coupling appears in the MoSSe/Ti3C2 heterostructures and the MoSSe layer can be metallized by the pristine Ti3C2. When the Ti3C2 layer is functionalized by the chalcogens and halogens, the interfacial coupling is significantly attenuated and the semiconductor characteristic of MoSSe layer can be maintained. The electric contact type is investigated based on these functionalized heterostructures. The obtained results suggest that those functional atoms with large (small) electronegativity tend to lead to p-type (n-type) electric contact. The current work proposes a practical approach to modulate the interfaces' electric contact type.