A powerful approach to develop nitrogen-doped graphene sheets: theoretical and experimental framework

We have reported a novel route to develop highly conductive graphene sheets using camphor as a natural precursor followed by nitrogen doping via low-temperature post-annealing treatment. The effect of nitrogen-doped (N-doped) graphene sheets and undoped graphene sheets on electrical properties has been studied in detail. We reveal that by precise control of post-annealing temperature and nitrogen doping level, the sheet resistance of graphene can be achieved to as low as ~ 280 Ω/□ as well as demonstrating N-type degenerate semiconducting properties. Moreover, we have performed ab initio calculations of undoped and N-doped graphene with varying concentrations of 1%, 2%, 3% and 5% doping in a supercell of 100 atoms. A semi-empirical Extended Hückel Tight Binding model was utilized to study the Bandgap, projected density of states (PDOS) and the Total Energy of all the doped and undoped graphene structures. It was found that with an increase in the dopant concentration in a monolayer graphene supercell leads to an opening in the bandgap at the k-point of the band structure. These results lead to an agreement of N-type behavior of the graphene structure which is supported by the PDOS results of the valence orbitals of graphene.