Title: Hierarchical On-Surface Synthesis of Graphene Nanoribbon Heterojunctions

Abstract

Bottom-up graphene nanoribbon (GNR) heterojunctions are nanoscale strips of graphene whose electronic structure abruptly changes across a covalently bonded interface. Their rational design offers opportunities for profound technological advancements enabled by their extraordinary structural and electronic properties. Thus far, the most critical aspect of their synthesis, the control over sequence and position of heterojunctions along the length of a ribbon, has been plagued by randomness in monomer sequences emerging from step-growth copolymerization of distinct monomers. All bottom-up GNR heterojunction structures created so far have exhibited random sequences of heterojunctions and, while useful for fundamental scientific studies, are difficult to incorporate into functional nanodevices as a result. In contrast, we describe a hierarchical fabrication strategy that allows the growth of bottom-up GNRs that preferentially exhibit a single heterojunction interface rather than a random statistical sequence of junctions along the ribbon. Such heterojunctions provide a viable platform that could be directly used in functional GNR-based device applications at the molecular scale. Our hierarchical GNR fabrication strategy is based on differences in the dissociation energies of C-Br and C-I bonds that allow control over the growth sequence of the block copolymers from which GNRs are formed and consequently yields a significantly higher proportionmore » of single-junction GNR heterostructures. In conclusion, scanning tunneling spectroscopy and density functional theory calculations confirm that hierarchically grown heterojunctions between chevron GNR (cGNR) and binaphthyl-cGNR segments exhibit straddling Type I band alignment in structures that are only one atomic layer thick and 3 nm in width.« less

Authors:

Bronner, Christopher  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-0083-5089"

Durr, Rebecca A. ^[2]; Rizzo, Daniel J. ^[1]; Lee, Yea-Lee ^[3]; Marangoni, Tomas ^[2]; Kalayjian, Alin Miksi ^[2]; Rodriguez, Henry ^[1]; Zhao, William ^[1]; Louie, Steven G. ^[4]; Fischer, Felix R.  ^[5];

• Search DOE PAGES for author "Fischer, Felix R."
• Search DOE PAGES for ORCID "0000-0003-4723-3111"

Crommie, Michael F.  ^[6]

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• Search DOE PAGES for ORCID "0000-0001-8246-3444"

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1. Univ. of California, Berkeley, CA (United States). Dept. of Physics
2. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry
3. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Pohang Univ. of Science and Technology (POSTECH) (Korea, Republic of). Dept. of Physics
4. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
5. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Kavli Energy NanoSciences Inst.
6. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division; Univ. of California, Berkeley, CA (United States). Kavli Energy NanoSciences Inst.

Publication Date:

Tue Jan 30 00:00:00 EST 2018

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)

OSTI Identifier:

1461135

Grant/Contract Number:  

AC02-05CH11231; SC0010409; DMR-1508412; LPDS 2014-09

Resource Type:

Accepted Manuscript

Journal Name:

ACS Nano

Additional Journal Information:

Journal Volume: 12; Journal Issue: 3; Journal ID: ISSN 1936-0851

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; bottom-up fabrication; electronic structure; graphene nanoribbon; heterojunction; hierarchical growth; on-surface synthesis