Formation of Monolayer Graphene by Annealing Sacrificial Nickel Thin Films

Graphene films have been formed by annealing Ni thin films at 800 degrees C under vacuum conditions. The Ni thin films are deposited on Si/SiO2 and, following annealing, have a polycrystalline morphology with grain sizes on the order of 1 mu m. Following growth, the Ni is removed by etching, and the graphene is transferred as a single continuous layer onto a separate surface. The fraction of monolayer graphene is investigated using optical and electron microscopy and Raman spectroscopy and is shown to be >75%.