Small bandgap features achieved in atomically precise 17-atom-wide armchair-edged graphene nanoribbons

TL;DR

This paper reports the successful bottom-up synthesis of 17-atom-wide armchair-edged graphene nanoribbons with small bandgaps, advancing the potential for GNR-based electronic devices by achieving narrower bandgaps than previously possible.

Contribution

It introduces a novel bottom-up synthesis method for 17-AGNRs with smaller bandgaps, improving electronic properties over prior GNRs.

Findings

17-AGNRs have the smallest bandgap among bottom-up GNRs.

17-AGNRs exhibit the smallest electron/hole effective mass.

Successful synthesis on Au(111) demonstrates potential for device applications.

Abstract

Graphene nanoribbons (GNRs) synthesized using a bottom-up technique potentially enable future electronic devices owing to the tunable electronic structures depending on the well-defined width and edge geometry. For instance, armchair-edged GNRs (AGNRs) exhibit width-dependent bandgaps. However, the bandgaps of AGNRs synthesized experimentally thus far are relatively large, well above 1 eV. Such a large bandgap may deteriorate device performances due to large Schottky barriers and carrier effective masses. We describe the bottom-up synthesis of AGNRs with a smaller bandgap using dibromobenzene-based precursors. Two types of AGNRs with different widths of 17 and 13 carbon atoms were synthesized on Au(111), and their atomic and electronic structures were investigated by scanning probe microscopy and spectroscopy. We reveal that the 17-AGNRs has the smallest bandgap as well as the smallest electron/hole effective mass among bottom-up AGNRs reported thus far. The successful synthesis of 17-AGNRs is a significant step toward the development of GNR-based electronic devices.