Chloride-intercalated continuous chemical vapor deposited graphene film with discrete adlayers

Heteroatom doping can open the bandgap and increase the carrier density, thus extending the applications of graphene. Iron chloride (FeCl₃) intercalation has proven to be an efficient method for the heavy doping of graphene. In this study, we prepared continuous chemical vapor deposited graphene (CVD-G) consisting of hexagonal adlayer domains to study the FeCl₃ intercalation. The structure of the FeCl₃-treated CVD-G was easily characterized via atomic force microscopy because of the change in the interlayer distance. FeCl₃ crystals several nanometers thick were integrated with the graphene surface, and FeCl₃ layer flakes were intercalated between the CVD-G adlayers. The G-band position and two-dimensional band shape in the Raman spectra confirmed the intercalation of the FeCl₃ between the graphene layers. The FeCl₃ intercalation increased the electrical conductivity of the CVD-G with a well-maintained transmittance, which could be beneficial for a sensitive photodetector.