Spectroscopic investigation of nitrogen doped graphene

Current research efforts are aimed at controlling the electronic properties via doping graphene. Previously, dopant-induced changes in the Fermi velocity were observed to result in an effectively downshifted Raman peak below the G′-band for n-doped carbon nanotubes. However, in the case of N-doped graphene, we find that several Raman features vary depending upon both dopant concentration and its bonding environment. For instance, only pyridinic/pyrrolic dopants were observed to result in intense D/D′-bands with a concomitant downshift in the G′-band. Here, we correlate x-ray photoelectron measurements with Raman spectra to elucidate effects of dopant bonding configuration on vibrational properties of graphene.