Defects, band bending and ionization rings in MoS2

Iolanda Di Bernardo, James Blyth, Liam Watson, Kaijian Xing, Yi Hsun Chen, Shao Yu Chen, Mark T. Edmonds, Michael S. Fuhrer

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Chalcogen vacancies in transition metal dichalcogenides are widely acknowledged as both donor dopants and as a source of disorder. The electronic structure of sulphur vacancies in MoS2however is still controversial, with discrepancies in the literature pertaining to the origin of the in-gap features observed via scanning tunneling spectroscopy (STS) on single sulphur vacancies. Here we use a combination of scanning tunnelling microscopy and STS to study embedded sulphur vacancies in bulk MoS2 crystals. We observe spectroscopic features dispersing in real space and in energy, which we interpret as tip position- and bias-dependent ionization of the sulphur vacancy donor due to tip induced band bending. The observations indicate that care must be taken in interpreting defect spectra as reflecting in-gap density of states, and may explain discrepancies in the literature.

Original languageEnglish
Article number174002
Number of pages8
JournalJournal of Physics: Condensed Matter
Volume34
Issue number17
DOIs
Publication statusPublished - 24 Feb 2022

Keywords

  • defects
  • ionization rings
  • MoS2
  • STM
  • TMDs

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