Direct formation of graphene films on dielectric substrates is investigated by the “etching-precipitation” method which converts metal-carbon mixed films to graphene films by etching metal away by Cl 2 at 600–650 °C. Here we report a new approach for improved control of the layer number and continuity of the graphene films. Reactive sputtering of Fe in C 2 H 4 /Ar enabled fine control of the carbon concentrations and thicknesses of the initial Fe-C films, which yielded continuous multilayer graphene films of controllable average layer numbers of ~10–40, low resistivity down to ~240 μΩ cm, and high Raman G-band to D-band intensity ratio up to 16 directly on SiO 2 substrates. We also show that the carbon concentration of the initial Fe-C films determines the film continuity and crystallinity of the graphene.
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