Synthesis of integrated graphene films with self-assembled single-layer channels and multi-layer electrodes via a single process

Integrated graphene films (IGFs) with self-assembled single-layer graphene as a channel and multi-layer graphene as an electrode material were synthesized simultaneously using a one-step process by thermal chemical vapor deposition. The prominent difference in graphene growth rate between Ni and Cu catalytic substrates made enable to synthesize the IGFs with self-assembled single-layer and multi-layer graphene on a Cu foil with pre-patterned Ni films. The thickness of multi-layer graphene for IGFs was precisely controlled by optimizing conditions including the injection temperature of carbon feedstock and the surface concentration of Ni atoms affected by the inter-diffusion related to the growth temperature and time. The thickness and crystallinity of synthesized IGFs were evaluated by resonant Raman spectroscopy. We fabricated the IGFs-based field effect transistors (FETs) to examine electrical transport properties of the films. These results suggest that the synthesis technique for IGFs could lead to mass fabrication of wearable graphene-based FETs in the near future.