Characterization of graphene synthesized by low-pressure chemical vapor deposition using N-Octane as precursor

We report single-layer graphene synthesis using high-carbon content N-Octane as precursor. Unlike methanol, ethanol and other liquid carbon precursors, N-Octane is oxygen free and its molecular structure is simply a common hydrocarbon. Optimal precursor pressure for synthesis was found to be at 5-20 mTorr range, as at higher partial pressures we have achieved bilayer and few-layer coverage of the copper substrates with {111} plane parallel to the surface, as revealed by Raman spectroscopy. We could lower the synthesis temperature down to 850 °C and still obtained graphene layers with low concentration of defects. For the complete coverage of the substrates, we report shorter than usual synthesis time, of no more than 5 min. Characterization of graphene layers were performed using Raman scattering spectroscopy and mapping, UV-vis transmittance as well as atomic force microscopy, scanning tunneling microscopy and scanning tunneling spectroscopy.