Electronic properties of graphene nanoribbons with line-edge roughness doped with nitrogen and boron

摘要

Graphene has enormous potential in nanoelectronics because of its remarkable electronic properties. Pristine graphene is a zero-bandgap semimetal nanomaterial unsuitable for logic devices. Graphene nanoribbons (GNRs), which are strips of graphene, have gained considerable research attention. During the fabrication of GNRs, a number of carbon atoms are removed from the ribbons' edges by cutting processes, thereby causing line-edge roughness, which is common in typical graphene. Substitution doping is a crucial method to adjust the electronic properties of materials. Based on the nearest-neighbour tight-binding method and non-equilibrium Green's function formalism, a GNR tight-binding model is presented. This research focuses on 13-armchair-edged GNRs with line-edge roughness that are doped with nitrogen or boron. Furthermore, the band structure and local density of states of both pristine and non-pristine GNRs are analysed. This study confirms that the line-edge roughness effect causes band-gap reduction. In addition, p-type doping decreases the band gap further than n-type doping. Nevertheless, the line-edge roughness effect is more prominent than the effect caused by doping. The study determines the effects and interaction of non-idealities, namely, substitutional impurities and vacancies, in GNRs having edge roughness.