Activating impurity effect in edge nitrogen-doped chevron graphene nanoribbons

Abstract

Doping has been regarded as one of the most important band structure engineering methods for graphene and its derivatives. Here, we theoretically investigate the chevron-type graphene nanoribbon (CGNR) which is doped by nitrogen in its edges (N-CGNR). The impurity effect can be activated by hydrogen efficiently. When each N atom is adsorbed by a H atom, the σ bond of N induced by selfhybridization is replaced by the N-H sp 2 bond, leaving two p z electrons perpendicular to the CGNR plane. Only one p z electron can be bonded with the nearest C atom. Therefore, the residual p z electron is delocalized from the N atom and induces the n-type impurity effect. We have calculated the binding energies of N-H bonds and found they are stable and can be manipulated independently without impacting the other bonds. A molecular dynamic (MD) simulation under high temperature further verifies that the N-H bonds in some specific positions can even be stable at 2000 K. Finally, the activated impurity effect is exhibited in the transport properties of CGNR based devices, indicating its wide application prospects.

Preferential Graphitic-Nitrogen Formation in Pyridine-Extended graphene Nanoribbons

“…It is found at the edges of the GNRs and causes a rigid downshift of valence (VB) and conduction bands (CB) which has been exploited to create local p-n junctions in GNRs 7,22,38,39 . On the other end, graphitic-N with three bonds to neighboring C atoms and an extra electron partially shared with the π orbitals 37,40 reduces the bandgap and leads to the formation of a new in-gap state localized at the heteroatom. However, the formation of graphitic-N in GNRs remains elusive.…”

Growth Mechanism of Chevron Graphene Nanoribbons on (111)-Oriented Coinage Metal Surfaces

“…While armchair GNRs (aGNR), and in particular 7-aGNR obtained from 10,10′-dibromo-9,9′-bianthracene, represent by far the most studied GNR type, chevron GNRs (cGNRs) based on 6,11-dibromo-1,2,3,4-tetraphenyltriphenylene (precursor 1 , Figure ) have also attracted particular attention. They have been extensively studied experimentally as well as theoretically, ,− also by considering atomic modifications such as the introduction of heteroatoms − or the addition of bulky edge groups. − ,− While most of these studies highlight the interest of GNR as a final product, the on-surface growth process and the different intermediate states, leading to the GNR formation have been only scarcely studied and rarely systematically addressed.…”

Charge Transport Mechanism in Chevron-Graphene Nanoribbons

“…Recent experimental evidence suggests C-GNRs as promising materials for applications in organic electronics and photovoltaics . Several other works have dealt with the synthesis of C-GNR. − Some studies have shown that C-GNRs share interesting properties that arise in different carbon allotropes while presenting other unique features. , Finally, possible applications of C-GNRs in heterojunctions have also already been reported . However, so far, the literature lacks the theoretical description of its electronic and transport properties.…”