Tight binding model study of boron/nitrogen doped graphene

Abstract

The pristine graphene is a zero band gap semiconductor, where conduction and valence bands touch each other at the Dirac point. We report here the effect of fifty percent doping of graphene by boron/nitrogen on the electron density of states. We propose a tight binding model Hamiltonian of boron/nitrogen doped graphene consisting of nearest neighbor, next nearest neighbor and next to next nearest neighbor pz - electron hoppings in the graphene plane. We have doped graphene with electronegative atom like nitrogen and electropositive atom like boron in the Hamiltonian. The total Hamiltonian is solved by Zubarev’s double time single particle Green’s function technique. The electron density of states is calculated from the imaginary part of the electron Green’s functions and computed numerically. It is observed that the electron density of states in doped graphene exhibits a clear gap near the Dirac point as compared to zero band gap in pristine graphene and a reduced gap as compared to pure hexagonal boron nitride.