Large-area bilayer graphene synthesis in the hot filament chemical vapor deposition reactor

• To obtain double layer graphene, we start by synthesizing polycrystalline graphene by hot filament chemical vapor deposition (HFCVD).
• We fabricated transparent and conductive graphene films.
• Hot filament chemical vapor deposition technique is reliable for yielding graphene material with large area coverage.

We fabricated large area bilayer graphene by hot filament chemical vapor deposition (HFCVD) on Cu foil. The HFCVD technique can represent a significant advantage over other techniques for industrial scaling at low cost. We performed systematic experiments to determine the best parameters to obtain uniform graphene coverage over an area of ~ 16 cm2. The experimental growth parameters are grouped into two distinct regions according to the products obtained: (A) continuous bilayer graphene with low defect density and (B) continuous bilayer graphene with high defect density. The optimum graphene films obtained are uniform bilayer with low defect density, greater than 90% transmittance in the visible region, and no gaps. The high quality of the bilayer graphene was confirmed by Raman spectroscopy mapping. The results show that the ratio of 2D to G peak intensities (I2D/IG) is in the 0.9–1.6 range over 90% of the area. Moreover, we employed the static cling property of polyethylene terephthalate (PET) to preserve the integrity of the as-grown graphene films in the transfer process, showing that the graphene films become well attached to the SiO2/Si substrates while the PET films were completely peeled off.