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Nano Research

Article Title

Sulfur-doped graphene nanoribbons with a sequence of distinct band gaps

Authors

Yan-Fang Zhang, Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37235, USA
Yi Zhang, Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
Geng Li, Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
Jianchen Lu, Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
Yande Que, Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
Hui Chen, Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
Reinhard Berger, Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany Center for Advancing Electronics Dresden (cfaed) & Department of Chemistry and Food Chemistry, Technische Universitt Dresden, D-01069 Dresden, Germany
Xinliang Feng, Center for Advancing Electronics Dresden (cfaed) & Department of Chemistry and Food Chemistry, Technische Universitt Dresden, D-01069 Dresden, Germany School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Klaus Müllen, Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany
Xiao Lin, Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
Yu-Yang Zhang, Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37235, USA
Shixuan Du, Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
Sokrates T. Pantelides, Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37235, USA Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China
Hong-Jun Gao, Institute of Physics & University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190, China

Keywords

bottom-up fabrication, chevron-type graphene nanoribbons, nanoscale quantum dots, scanning tunneling microscopy, density functional theory

Abstract

ABSTRACT Unlike graphene sheets, graphene nanoribbons (GNRs) can exhibit semiconducting band gap characteristics that can be tuned by controlling impurity doping and the GNR widths and edge structures. However, achieving such control is a major challenge in the fabrication of GNRs. Chevron-type GNRs were recently synthesized via surface-assisted polymerization of pristine or N-substituted oligophenylene monomers. In principle, GNR heterojunctions can be fabricated by mixing two different monomers. In this paper, we report the fabrication and characterization of chevron-type GNRs using sulfur-substituted oligophenylene monomers to produce GNRs and related heterostructures for the first time. First-principles calculations show that the GNR gaps can be tailored by applying different sulfur configurations from cyclodehydrogenated isomers via debromination and intramolecular cyclodehydrogenation. This feature should enable a new approach for the creation of multiple GNR heterojunctions by engineering their sulfur configurations. These predictions have been confirmed via scanning tunneling microscopy and scanning tunneling spectroscopy. For example, we have found that the S-containing GNRs contain segments with distinct band gaps, i.e., a sequence of multiple heterojunctions that results in a sequence of quantum dots. This unusual intraribbon heterojunction sequence may be useful in nanoscale optoelectronic applications that use quantum dots.

Graphical Abstract

Publisher

Tsinghua University Press

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