Synthesis of graphene layers on polycrystalline Ni foil using liquid ethanol.

In our manuscript we demonstrate an easy and technologically relevant approach to the successful growth of monolayer and multilayer graphene layers on polycrystalline nickel (Ni-poly) substrates using liquid ethanol (C2H5OH) as a carbon precursor. The ex situ immersed in liquid ethanol Ni foils were subsequently in situ thermally annealed in UHV conditions. The graphene formation process and the layer's quality are analyzed using X-ray spectroscopy techniques (XPS and NEXAFS) as well as Raman spectroscopy, complemented by scanning electron microscopy for morphology assessment. This study demonstrates that graphene growth occurs through the decomposition of C2H5OH molecules at low annealing temperatures, partially releasing -OH and H2O, followed by the formation of C-C dimers, which aggregate into graphene layers at high annealing temperatures. The role of nickel carbide (Ni2C) during the graphene synthesis is also discussed. The obtained data provide precise insights into the graphene formation mechanisms giving information on the optimal synthesis temperature as well as on the layer thicknesses, quality, and electronic structure.