The Effect of Nitrogen on the Structural and Electronic Properties of Graphene Sheet using Density Functional Theory

Abstract The present research focuses on a theoretical study of structural and electronic properties of pure graphene sheet and then adding different number of N2 atoms. The calculations are carried out using the density functional theory (DFT) with hybrid functional B3LYP/6-31G level to investigate the proposed structures. Gauss View 5.0.8 program is used to design the structures of pure and doped graphene sheets. These structures are relaxed by employing the PM6 semi-empirical method with the hybrid functional B3LYPDFT at Gaussian 09 package. The results of the structural properties of the studied graphene sheets showed that good relaxation of the structures, the constant bonds values in the pure graphene sheets in the same ranges of the carbon rings structures. We calculate the total energy, High Occupied Molecular Orbital (HOMO) and Low Unoccupied Molecular Orbital (LUMO) energies and forbidden energy gap. The result of the total energy of that doping graphene sheets is result of the binding energy of each structure and indicates that these structures have relaxation, and the effect of adding N2 atoms in pure graphene sheet on the total energy of the molecule is effective. All doping graphene sheets have small forbidden energy gap, but it vibrates depending on the length and number of each sheet and the position of N2 atoms in the sheets.