Nanoscale Probing of Image-Potential States and Electron Transfer Doping in Borophene Polymorphs

Xiaolong Liu, Luqing Wang, Boris I. Yakobson, Mark C. Hersam*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Because synthetic 2D materials are generally stabilized by interfacial coupling to growth substrates, direct probing of interfacial phenomena is critical for understanding their nanoscale structure and properties. Using field-emission resonance spectroscopy with an ultrahigh vacuum scanning tunneling microscope, we reveal Stark-shifted image-potential states of the v1/6 and v1/5 borophene polymorphs on Ag(111) with long lifetimes, suggesting high borophene lattice and interface quality. These image-potential states allow the local work function and interfacial charge transfer of borophene to be probed at the nanoscale and test the widely employed self-doping model of borophene. Supported by apparent barrier height measurements and density functional theory calculations, electron transfer doping occurs for both borophene phases from the Ag(111) substrate. In contradiction with the self-doping model, a higher electron transfer doping level occurs for denser v1/6 borophene compared to v1/5 borophene, thus revealing the importance of substrate effects on borophene electron transfer.

Original languageEnglish (US)
Pages (from-to)1169-1174
Number of pages6
JournalNano letters
Volume21
Issue number2
DOIs
StatePublished - Jan 27 2021

Keywords

  • density functional theory
  • field-emission resonance spectroscopy
  • scanning tunneling microscopy
  • two-dimensional boron
  • work function

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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