First-principle investigation of Ti wetting layer influence on metal-graphene contact

Metal (M) /grapheme (Gr) contact has attracted much attention since the contact resistance (R_c) between Gr and metal electrode is crucially important for achieving high performance of grapheme-based devices [[1]-[15]]. Published experimental works on metal/graphene contacts generally adopted Gr/Ti/Metal structure to enhance the interfacial adhesion [[1]-[8]]. However, how the presence of Ti wetting layer can influence the global response of Gr-based device remains unclear. To present a clear physical understanding and optimizing transport between metal electrodes and graphene with Ti wetting layer, the binding energy, band structure, interface potential profile and contact resistance of the Gr/Ti/Metal (Al, Cu, Au, Pt, Pd) systems were studied for the first time by first-principle and NEGF methods in this paper. The results provide insights into contact resistance optimization and the ultimate scalability of graphene-based devices.