Graphene layers fabricated from the Ni/a-SiC bilayer precursor

Abstract

This paper considers a synthesis of graphene flakes on the Ni surface by vacuum long and nitrogen rapid thermal treatment of the sandwich amorphous (a) SiC/Ni multilayer deposited on silicon wafer by magnetron sputtering technique. The lateral size of graphene flakes was estimated to be about hundreds of micrometers while the thickness estimated using Raman scattering varied from one to few layers in case of vacuum annealing. Rapid thermal annealing (RTA) in nitrogen ambient results in formation of multilayer graphene with surface covering up to 80%. The graphene layers synthesized on Ni during CVD process was used as reference samples. Atomic force microscopy (AFM) is not able to detect graphene flakes in regime of surface topology examination because of large roughness of Ni surface. Employment of scanning Kelvin probe force microscopy (SKPFM) demonstrates correlation of the surface potential and graphene flakes visible in optical microscopy. Using the KPFM method, potential differences between Ni and graphene were determined.