Synthesis of Graphene Nanoribbons on a Kinked Au Surface: Revealing the Frontier Valence Band at the Brillouin Zone Center

• Published in: Journal of physical chemistry. C 2020-07, Vol.124 (28), p.15474-15480
• Main Authors: El-Sayed, Afaf, Piquero-Zulaica, Ignacio, Abd El-Fattah, Zakaria M, Kormoš, Lukáš, Ali, Khadiza, Weber, Andrew, Brede, Jens, de Oteyza, Dimas G, Lobo-Checa, Jorge, Ortega, J. Enrique, Corso, Martina
• Format: Article
• Language: English
• Subjects: C: Physical Processes in Nanomaterials and Nanostructures
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.0c02801

Graphene nanoribbons (GNRs) can be synthesized with atomic precision through on-surface chemistry of self-assembled organic precursors on metal surfaces. Here, we examine the growth of seven-armchair GNRs (7-AGNRs) on the Au(16 14 15) vicinal surface, namely, a surface vicinal to Au(111) that features kinked steps. During the thermal activation of the polymerization and cyclodehydrogenation processes that produce the GNRs, the kinked substrate undergoes a strong step-edge reshaping, accompanied by a massive missing-row reconstruction within (111) terraces that aligns GNRs preferentially along two equivalent [11̅0] directions. Using angle-resolved photoemission, we are able to detect the occupied frontier band of the 7-AGNR at the center of the first Brillouin zone, as predicted by theoretical calculations. This allows to unambiguously determine the relevant 7-AGNR band properties, namely, energy and effective mass.