Electronic and Transport Properties of Unbalanced Sublattice N-Doping in Graphene

Abstract

Using both first-principles techniques and a real-space Kubo-Greenwood approach, electronic and transport properties of nitrogen-doped graphene with a single sublattice preference are investigated. Such a breaking of the sublattice symmetry leads to the appearance of a true band gap in graphene electronic spectrum even for a random distribution of the N dopants. More surprisingly, a natural spatial separation of both types of charge carriers at the band edge is predicted, leading to a highly asymmetric electronic transport. Both the presence of a band gap, allowing large on/off ratio, and an asymmetric transport pave a new route toward efficient graphene-based field-effect transistors.

Electronic transport in graphene nanoribbons with sublattice-asymmetric doping

“…This is further evidenced by the hole-side transmission, which is significantly reduced relative to the pristine case and has its plateau features almost completely smeared out. This electron-hole asymmetry is consistent with results in graphene sheets, where reduced mobility on the hole side is associated with a pseudospin polarization giving a higher occupation of the undoped (doped) sublattice on the electron (hole) side [22]. We have confirmed that this feature is also present in the AGNR case by examining the sublattice dependent averaged DOS.…”

“…We take |t| as the unit of energy and include substitutional N dopants by a change of on-site energy = −|t|. More accurate parametrizations can be achieved [22,46,47], but the qualitative behavior described here is reasonably independent of impurity species or parametrization. We will discuss the change in carrier density induced by such dopants at the end of Sec.…”

“…Such doping leads to different average potentials on each sublattice and is equivalent to introducing an effective mass term. Extended graphene sheets with sublattice-asymmetric impurity distributions are predicted to display electronic and transport band gaps, and electron-hole asymmetry in their conductivity [18][19][20][21][22].…”

Epitaxial B-Graphene: Large-Scale Growth and Atomic Structure

“…The prediction of a gap is consistent with our ARPES study of N-graphene, grown on Ni(111), 7 but transport measurements are still required to provide indisputable evidence. In the case of B-graphene/SiO 2 the transport studies revealed notable band gap, depending on the boron concentration, 27 but the origin of the gap is not clear in view of ref 5. It should be noticed that there is another surface, which is very similar to Ni(111) regarding its crystal structure and properties, namely Co(0001).…”

Boron and nitrogen doping in graphene antidot lattices

“…34 The transport properties of boron or nitrogen doped graphene were studied theoretically by Lherbier et al 35 while the effect of unbalanced sublattice nitrogen doping was studied by Lherbier and other coworkers. 36 Isolated boron and nitrogen doping in GNRs and near graphene edges has also been studied theoretically. 37,38 Nitrogen doped carbon nanotubes 39 and GNRs 40 have been realized experimentally, and doped GNRs have been studied theoretically to a large extent.…”