Self-build of C 60-C 70 molecular heterojunctions on highly oriented pyrolytic graphite

Research output: Contribution to journalArticlepeer-review

Authors

  • Luan Guo
  • Yitao Wang
  • Dogan Kaya
  • Zhiming Wang
  • Min Zhang

Colleges, School and Institutes

Abstract

Building a novel heterojunction with hybrid structures can create new physical properties and enable unique functionality. We investigated the build of C60-C70 heterojunction between C60 and C70 molecular layers by Scanning Tunnelling Microscopy (STM). The C60-C70 organic molecular heterojunction was successfully built by layer-by-layer growth method on the HOPG surface using ultra-high vacuum STM. Both molecules can rotate freely within their corresponding molecular layers at room temperature. When C70 molecules are deposited onto a preformed first layer of C60, the C70 molecules assemble into a close-packed second layer with a lattice-matched to the underlying C60 layer. The C70 molecules in the second layer adopt a standing up configuration with its long molecular axis perpendicular to the substrate which is accompanied by the elimination of the energy component associated with the rotation around the short molecular axis. C70 and C60 molecules at layers margins become mobile due to annealing processes and can jump up and form a new packing layer on its origin layer, C70 molecules remain as isolated molecules standing with their long axis perpendicular to the layers. The C60-C70 molecular heterojunctions allow building a lateral/vertical van der Waals heterojunctions.

Bibliographic note

Funding Information: Chinese Scholarship Council for providing a scholarship to Lu’an Guo. Special thanks to Dogan Kaya who generously volunteered his time and expertise during the revision. The authors also acknowledge the support from the National Key Research and Development Program (No. 2019YFB2203400), UESTC Shared Research Facilities of Electromagnetic Wave and Matter Interaction (Y0301901290100201) and Young Scientists Fund of the Basic and Applied Basic Research of Guangdong (2019A1515110021). Funding Information: Chinese Scholarship Council for providing a scholarship to Lu'an Guo. Special thanks to Dogan Kaya who generously volunteered his time and expertise during the revision. The authors also acknowledge the support from the National Key Research and Development Program (No. 2019YFB2203400), UESTC Shared Research Facilities of Electromagnetic Wave and Matter Interaction (Y0301901290100201) and Young Scientists Fund of the Basic and Applied Basic Research of Guangdong (2019A1515110021). Publisher Copyright: © 2020 Elsevier B.V. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

Details

Original languageEnglish
Article number148142
JournalApplied Surface Science
Volume538
Early online date13 Oct 2020
Publication statusPublished - 1 Feb 2021

Keywords

  • Fullerene, HOPG, Heterojunctions, Scanning tunnelling microscopy, Self-build