Thickness-Controlled Growth of Multilayer Graphene on Ni(111) Using an Approximate Equilibrium Segregation Method for Applications in Spintronic Devices

Thickness-controlled multilayer graphene has been attracting wide interest in electronic and spintronic devices due to its tunable electronic structure and spin transport properties. In particular, the strong spin filtering effect in a lattice-matched Ni(111)/multilayer graphene heterostructure provides an ideal platform for developing high-performance spin valves and magnetic tunnel junctions. However, the thickness-controlled synthesis of multilayer graphene on Ni(111) substrates is still a large challenge, which seriously restricts the development of graphene spintronic devices. Here, we report an approximate equilibrium segregation method for large-area multilayer graphene films on Ni(111) substrates by regulating the growth process of carbon dissolution and segregation. The uniformity and coverage of multilayer graphene films are controlled precisely in an atmospheric tube furnace system by modulating the Ni film thickness, gas atmosphere, and cooling rate. Characterization results systematically confirm the production of high-coverage, high-quality multilayer graphene on Ni(111) substrates. This work provides a reliable method for the controllable fabrication of multilayer graphene on single-crystal ferromagnetic substrates, which would contribute to the application of graphene spintronic devices.