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Symmetry-Driven Band Gap Engineering in Hydrogen Functionalized Graphene

Jørgensen, Jakob Holm; Čabo, Antonija Grubišić; Balog, Richard; Kyhl, Line; Groves, Michael N.; Cassidy, Andrew Martin; Bruix, Albert; Bianchi, Marco; Dendzik, Maciej and Arman, Mohammad Alif LU , et al. (2016) In ACS Nano 10(12). p.10798-10807
Abstract

Band gap engineering in hydrogen functionalized graphene is demonstrated by changing the symmetry of the functionalization structures. Small differences in hydrogen adsorbate binding energies on graphene on Ir(111) allow tailoring of highly periodic functionalization structures favoring one distinct region of the moiré supercell. Scanning tunneling microscopy and X-ray photoelectron spectroscopy measurements show that a highly periodic hydrogen functionalized graphene sheet can thus be prepared by controlling the sample temperature (Ts) during hydrogen functionalization. At deposition temperatures of Ts = 645 K and above, hydrogen adsorbs exclusively on the HCP regions of the graphene/Ir(111) moiré structure. This... (More)

Band gap engineering in hydrogen functionalized graphene is demonstrated by changing the symmetry of the functionalization structures. Small differences in hydrogen adsorbate binding energies on graphene on Ir(111) allow tailoring of highly periodic functionalization structures favoring one distinct region of the moiré supercell. Scanning tunneling microscopy and X-ray photoelectron spectroscopy measurements show that a highly periodic hydrogen functionalized graphene sheet can thus be prepared by controlling the sample temperature (Ts) during hydrogen functionalization. At deposition temperatures of Ts = 645 K and above, hydrogen adsorbs exclusively on the HCP regions of the graphene/Ir(111) moiré structure. This finding is rationalized in terms of a slight preference for hydrogen clusters in the HCP regions over the FCC regions, as found by density functional theory calculations. Angle-resolved photoemission spectroscopy measurements demonstrate that the preferential functionalization of just one region of the moiré supercell results in a band gap opening with very limited associated band broadening. Thus, hydrogenation at elevated sample temperatures provides a pathway to efficient band gap engineering in graphene via the selective functionalization of specific regions of the moiré structure.

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publication status
published
subject
keywords
band gap engineering, functionalization, graphene, hydrogen, Ir(111), photoemission spectroscopy, STM
in
ACS Nano
volume
10
issue
12
pages
10 pages
publisher
The American Chemical Society
external identifiers
  • scopus:85008400956
  • wos:000391079700022
ISSN
1936-0851
DOI
10.1021/acsnano.6b04671
language
English
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yes
id
31af6067-da93-4ea2-a6d2-fe4e3e1ea00a
date added to LUP
2017-01-23 12:26:09
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2017-11-19 04:36:56
@article{31af6067-da93-4ea2-a6d2-fe4e3e1ea00a,
  abstract     = {<p>Band gap engineering in hydrogen functionalized graphene is demonstrated by changing the symmetry of the functionalization structures. Small differences in hydrogen adsorbate binding energies on graphene on Ir(111) allow tailoring of highly periodic functionalization structures favoring one distinct region of the moiré supercell. Scanning tunneling microscopy and X-ray photoelectron spectroscopy measurements show that a highly periodic hydrogen functionalized graphene sheet can thus be prepared by controlling the sample temperature (T<sub>s</sub>) during hydrogen functionalization. At deposition temperatures of T<sub>s</sub> = 645 K and above, hydrogen adsorbs exclusively on the HCP regions of the graphene/Ir(111) moiré structure. This finding is rationalized in terms of a slight preference for hydrogen clusters in the HCP regions over the FCC regions, as found by density functional theory calculations. Angle-resolved photoemission spectroscopy measurements demonstrate that the preferential functionalization of just one region of the moiré supercell results in a band gap opening with very limited associated band broadening. Thus, hydrogenation at elevated sample temperatures provides a pathway to efficient band gap engineering in graphene via the selective functionalization of specific regions of the moiré structure.</p>},
  author       = {Jørgensen, Jakob Holm and Čabo, Antonija Grubišić and Balog, Richard and Kyhl, Line and Groves, Michael N. and Cassidy, Andrew Martin and Bruix, Albert and Bianchi, Marco and Dendzik, Maciej and Arman, Mohammad Alif and Lammich, Lutz and Pascual, José Ignacio and Knudsen, Jan and Hammer, Bjørk and Hofmann, Philip and Hornekaer, Liv},
  issn         = {1936-0851},
  keyword      = {band gap engineering,functionalization,graphene,hydrogen,Ir(111),photoemission spectroscopy,STM},
  language     = {eng},
  month        = {12},
  number       = {12},
  pages        = {10798--10807},
  publisher    = {The American Chemical Society},
  series       = {ACS Nano},
  title        = {Symmetry-Driven Band Gap Engineering in Hydrogen Functionalized Graphene},
  url          = {http://dx.doi.org/10.1021/acsnano.6b04671},
  volume       = {10},
  year         = {2016},
}