Graphene synthesis on Fe foil using thermal CVD

Graphene synthesis was performed on Fe foil at low temperature. A 100 μm-thick Fe foil as a catalyst and acetylene as a hydrocarbon source were used for graphene growth. With a low acetylene flow rate (5 sccm) and short exposure time (5 min), single- to few-layer graphene sheets partially covering the Fe substrate were obtained. With sufficient exposure times (15–30 min), and acetylene flow rates (25–50 sccm), continuous graphene layers were obtained at temperatures ranging from 600 °C to 800 °C. The measured Raman spectra showed that defects decreased with an increasing synthesis temperature. Even though the 2D and G peak intensities of the Raman spectrum appeared to be similar, the thickness of the graphene layers synthesized at 700 °C and 750 °C was measured to be as thick as ∼15 nm and ∼29 nm, respectively. Considering that the estimated number of graphene layers should be less than 2–3 without creating stacking disorder between the interlayers, it appears that an ordered stacking, (i.e., ABAB stacking) and therefore electronic coupling between layers, may not occur in the synthesized graphene layers on Fe foil under those process conditions.