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Title: On-Surface Synthesis and Characterization of 9-Atom Wide Armchair Graphene Nanoribbons

The bottom-up approach to synthesize graphene nanoribbons strives not only to introduce a band gap into the electronic structure of graphene but also to accurately tune its value by designing both the width and edge structure of the ribbons with atomic precision. Within this paper, we report the synthesis of an armchair graphene nanoribbon with a width of nine carbon atoms on Au(111) through surface-assisted aryl–aryl coupling and subsequent cyclodehydrogenation of a properly chosen molecular precursor. By combining high-resolution atomic force microscopy, scanning tunneling microscopy, and Raman spectroscopy, we demonstrate that the atomic structure of the fabricated ribbons is exactly as designed. Angle-resolved photoemission spectroscopy and Fourier-transformed scanning tunneling spectroscopy reveal an electronic band gap of 1.4 eV and effective masses of ≈0.1 m e for both electrons and holes, constituting a substantial improvement over previous efforts toward the development of transistor applications. We use ab initio calculations to gain insight into the dependence of the Raman spectra on excitation wavelength as well as to rationalize the symmetry-dependent contribution of the ribbons’ electronic states to the tunneling current. Lastly, we propose a simple rule for the visibility of frontier electronic bands of armchair graphene nanoribbons in scanning tunneling spectroscopy.
Authors:
ORCiD logo [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ; ORCiD logo [4] ;  [5] ;  [6] ;  [6] ;  [7] ;  [2] ; ORCiD logo [2] ;  [8] ; ORCiD logo [1]
  1. Swiss Federal Laboratories for Materials Science and Technology (Empa) (Switzerland). nanotech@surfaces Laboratory
  2. Max Planck Institute for Polymer Research (Germany)
  3. Swiss Federal Laboratories for Materials Science and Technology (Empa) (Switzerland). nanotech@surfaces Laboratory and NCCR MARVEL
  4. Rensselaer Polytechnic Institute, Troy, NY (United States). Department of Physics, Applied Physics, and Astronomy; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
  5. Rensselaer Polytechnic Institute, Troy, NY (United States). Department of Physics, Applied Physics, and Astronomy
  6. Paul Scherrer Institute (Switzerland). Swiss Light Source
  7. Dresden Univ. of Technology (Germany). Center for Advancing Electronics Dresden and Department of Chemistry and Food Chemistry
  8. Swiss Federal Laboratories for Materials Science and Technology (Empa) (Switzerland). nanotech@surfaces Laboratory; University of Bern (Switzerland). Department of Chemistry and Biochemistry
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 11; Journal Issue: 2; Journal ID: ISSN 1936-0851
Publisher:
American Chemical Society (ACS)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org:
USDOE Office of Science (SC); USDOE Laboratory Directed Research and Development (LDRD) Program
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; bottom-up synthesis; graphene nanoribbons; on-surface chemistry; Raman spectroscopy; scanning tunneling spectroscopy
OSTI Identifier:
1346658