Direct physical exfoliation and transfer of graphene grown via ethanol chemical vapor deposition

摘要

A standard exfoliation process of graphene involves several problems associated with damage of graphene and long-time consumption. Here we demonstrate a direct physical exfoliation and transfer processes of graphene grown via ethanol-chemical vapor deposition (CVD). Our exfoliation process exploits a polydimethylsiloxane (PDMS) stamp for conformal contact with graphene. Moreover, it rapidly exfoliates a few-layer graphene (FLG) film with high quality from entire graphene layers on Ni within 5 min. Indeed, the process time is significantly faster than few hours for a standard process. Even after exfoliation, our graphene shows high quality which is verified by the high intensity ratio of G band to D band (IG / ID >; 20) in Raman spectra. IG / ID of our graphene is approximately five times higher than that of standard graphene (IG / ID <; 4) that implies low defects in our graphene. The technology for exfoliating a FLG film can be used for highly desired layer-by-layer manipulation of graphene because it is still difficult to synthesize appropriate layers of graphene on an arbitrary substrate. Through the graphene transfer process, we integrate the exfoliated graphene film to a silicon dioxide (SiO₂) surface with low damage for various N/MEMS applications. Also, by employing ethanol vapor (i.e., cheap and stable) as a source of carbon for graphene synthesis, we improve a conventional synthesis process of graphene using methane gas (i.e., expensive and explosive).