From defect to effect: controlling electronic transport in chevron graphene nanoribbons

Abstract

While bottom-up synthesis allows for precise control over the properties of graphene nanoribbons (GNRs), the use of certain precursor molecules can result in edge defects, such as missing benzene rings that resemble a ``bite''. We investigate the adverse effect of the ``bite'' defects on the electronic transport properties in three chevron-type GNRs and discover that the extent of scattering is governed by the different defect positions. Applying the concepts learned in single GNRs, we engineer defects in two nanostructures to construct prototypical components for nanoelectronics. First, we design a switch, consisting of three laterally fused fluorenyl-chevron GNRs, and place a pair of ``bite'' defects to effectively allow the switching between 4 binary states corresponding to distinct current pathways. Second, we show that conscientious placement of a ``bite'' defect pair can increase conductance between two leads in a triple chevron GNR junction. Overall, we outline how the incorporation of ``bite'' defects affects transport properties in chevron-type nanostructures and provide a guide on how to design nanoelectronic components.

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.…”