Tuning the electronic structure of graphene through nitrogen doping: experiment and theory

Abstract

Tuning the electronic properties of graphene by doping atoms into its lattice makes it more applicable for electronic devices. We present a study of nitrogen doped graphene samples grown using chemical vapor deposition with a variety of synthesis conditions. Soft X-ray absorption and emission spectroscopy, which are techniques sensitive to the unoccupied and occupied partial electronic density of states, respectively, were used to study the electronic structure of N-doped graphene. Complementary full-potential, all-electron density functional theory calculations of the measured spectra reveal the existence of graphitic, pyridinic and nitrilic-like sites in the samples studied. Although our study shows that the defect type is sensitively related to the synthesis conditions, the graphitic configuration is found to be the most dominant one in each system studied. The dependence of the defect type on the sample growth conditions and the corresponding shifts in the Fermi energy level from the Dirac point, result in n- or p-type material being obtained.