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Local electronic structure of stable monolayers of α-MoO3−x grown on graphite substrate

Kowalczyk, Dorota A. ; Rogala, Maciej ; Szałowski, Karol ; Kozłowski, Witold ; Lutsyk, Iaroslav ; Piskorski, Michał ; Krukowski, Paweł ; Dabrowski, Paweł ; Belić, Domagoj LU and Cichomski, Michał , et al. (2021) In 2D Materials 8(2).
Abstract

We report on van der Waals epitaxy of two-dimensional (2D) molybdenum trioxide (MoO3−x) with monolayer thickness directly grown on highly oriented pyrolytic graphite by thermal evaporation under ultrahigh vacuum. The chemical composition, electronic and crystalline lattice structures of the mono-and few-layer MoO3−x sheets are analysed. Using scanning tunnelling microscopy and spectroscopy, we investigate the electronic properties of MoO3−x as a function of the number of layers and measure the apparent energy gap to be 0.4 eV for the first three layers of MoO3−x on graphite. We carried out density functional theory calculations to shed light on the mechanism underlying the observed narrow... (More)

We report on van der Waals epitaxy of two-dimensional (2D) molybdenum trioxide (MoO3−x) with monolayer thickness directly grown on highly oriented pyrolytic graphite by thermal evaporation under ultrahigh vacuum. The chemical composition, electronic and crystalline lattice structures of the mono-and few-layer MoO3−x sheets are analysed. Using scanning tunnelling microscopy and spectroscopy, we investigate the electronic properties of MoO3−x as a function of the number of layers and measure the apparent energy gap to be 0.4 eV for the first three layers of MoO3−x on graphite. We carried out density functional theory calculations to shed light on the mechanism underlying the observed narrow bandgap with oxygen deficiency. Moreover, the air exposure effect on monolayer MoO3−x is investigated confirming that the apparent bandgap closes, and additionally we show the reduction of the work function from 5.7 to 4.7 eV. We prove that it is possible to synthesize the 2D, non-stoichiometric, and electrically conductive MoO3−x.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
2D material, Electronic structure, Molybdenum oxide, Scanning tunnelling spectroscopy, Transition metal oxides, Work function
in
2D Materials
volume
8
issue
2
article number
025005
publisher
IOP Publishing
external identifiers
  • scopus:85098682063
ISSN
2053-1583
DOI
10.1088/2053-1583/abcf10
language
English
LU publication?
yes
id
be2522d0-a8f8-4fdc-8b4f-266a21d7227d
date added to LUP
2021-01-12 14:14:44
date last changed
2022-04-26 23:24:28
@article{be2522d0-a8f8-4fdc-8b4f-266a21d7227d,
  abstract     = {{<p>We report on van der Waals epitaxy of two-dimensional (2D) molybdenum trioxide (MoO<sub>3−x</sub>) with monolayer thickness directly grown on highly oriented pyrolytic graphite by thermal evaporation under ultrahigh vacuum. The chemical composition, electronic and crystalline lattice structures of the mono-and few-layer MoO<sub>3−x</sub> sheets are analysed. Using scanning tunnelling microscopy and spectroscopy, we investigate the electronic properties of MoO<sub>3−x</sub> as a function of the number of layers and measure the apparent energy gap to be 0.4 eV for the first three layers of MoO<sub>3−x</sub> on graphite. We carried out density functional theory calculations to shed light on the mechanism underlying the observed narrow bandgap with oxygen deficiency. Moreover, the air exposure effect on monolayer MoO<sub>3−x</sub> is investigated confirming that the apparent bandgap closes, and additionally we show the reduction of the work function from 5.7 to 4.7 eV. We prove that it is possible to synthesize the 2D, non-stoichiometric, and electrically conductive MoO<sub>3−</sub>x.</p>}},
  author       = {{Kowalczyk, Dorota A. and Rogala, Maciej and Szałowski, Karol and Kozłowski, Witold and Lutsyk, Iaroslav and Piskorski, Michał and Krukowski, Paweł and Dabrowski, Paweł and Belić, Domagoj and Cichomski, Michał and Kłusek, Zbigniew and Kowalczyk, Paweł J.}},
  issn         = {{2053-1583}},
  keywords     = {{2D material; Electronic structure; Molybdenum oxide; Scanning tunnelling spectroscopy; Transition metal oxides; Work function}},
  language     = {{eng}},
  number       = {{2}},
  publisher    = {{IOP Publishing}},
  series       = {{2D Materials}},
  title        = {{Local electronic structure of stable monolayers of α-MoO<sub>3−x</sub> grown on graphite substrate}},
  url          = {{http://dx.doi.org/10.1088/2053-1583/abcf10}},
  doi          = {{10.1088/2053-1583/abcf10}},
  volume       = {{8}},
  year         = {{2021}},
}