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Studies of Li intercalation of hydrogenated graphene on SiC(0001)

Watcharinyanon, S.; Johansson, L. I.; Zakharov, Alexei LU and Virojanadara, C. (2012) In Surface Science 606(3-4). p.401-406
Abstract
The effects of Li deposition on hydrogenated bilayer graphene on SiC(0001) samples, i.e. on quasi-freestanding bilayer graphene samples, are studied using low energy electron microscopy, micro-low-energy electron diffraction and photoelectron spectroscopy. After deposition, some Li atoms form islands on the surface creating defects that are observed to disappear after annealing. Some other Li atoms are found to penetrate through the bilayer graphene sample and into the interface where H already resides. This is revealed by the existence of shifted components, related to H-SiC and Li-SiC bonding, in recorded core level spectra. The Dirac point is found to exhibit a rigid shift to about 1.25 eV below the Fermi level, indicating strong... (More)
The effects of Li deposition on hydrogenated bilayer graphene on SiC(0001) samples, i.e. on quasi-freestanding bilayer graphene samples, are studied using low energy electron microscopy, micro-low-energy electron diffraction and photoelectron spectroscopy. After deposition, some Li atoms form islands on the surface creating defects that are observed to disappear after annealing. Some other Li atoms are found to penetrate through the bilayer graphene sample and into the interface where H already resides. This is revealed by the existence of shifted components, related to H-SiC and Li-SiC bonding, in recorded core level spectra. The Dirac point is found to exhibit a rigid shift to about 1.25 eV below the Fermi level, indicating strong electron doping of the graphene by the deposited Li. After annealing the sample at 300-400 degrees C formation of LiH at the interface is suggested from the observed change of the dipole layer at the interface. Annealing at 600 degrees C or higher removes both Li and H from the sample and a monolayer graphene sample is re-established. The Li thus promotes the removal of H from the interface at a considerably lower temperature than after pure H intercalation. (C) 2011 Elsevier B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Graphene, Bilayer, Hydrogenation, Li, LEEM, PES, LEED, ARPES
in
Surface Science
volume
606
issue
3-4
pages
401 - 406
publisher
Elsevier
external identifiers
  • wos:000300458600045
  • scopus:84855467601
ISSN
0039-6028
DOI
10.1016/j.susc.2011.10.023
language
English
LU publication?
yes
id
ef71aa13-2a58-4992-a773-ceb65e430ea1 (old id 2384449)
date added to LUP
2012-03-30 14:29:44
date last changed
2017-04-09 03:52:36
@article{ef71aa13-2a58-4992-a773-ceb65e430ea1,
  abstract     = {The effects of Li deposition on hydrogenated bilayer graphene on SiC(0001) samples, i.e. on quasi-freestanding bilayer graphene samples, are studied using low energy electron microscopy, micro-low-energy electron diffraction and photoelectron spectroscopy. After deposition, some Li atoms form islands on the surface creating defects that are observed to disappear after annealing. Some other Li atoms are found to penetrate through the bilayer graphene sample and into the interface where H already resides. This is revealed by the existence of shifted components, related to H-SiC and Li-SiC bonding, in recorded core level spectra. The Dirac point is found to exhibit a rigid shift to about 1.25 eV below the Fermi level, indicating strong electron doping of the graphene by the deposited Li. After annealing the sample at 300-400 degrees C formation of LiH at the interface is suggested from the observed change of the dipole layer at the interface. Annealing at 600 degrees C or higher removes both Li and H from the sample and a monolayer graphene sample is re-established. The Li thus promotes the removal of H from the interface at a considerably lower temperature than after pure H intercalation. (C) 2011 Elsevier B.V. All rights reserved.},
  author       = {Watcharinyanon, S. and Johansson, L. I. and Zakharov, Alexei and Virojanadara, C.},
  issn         = {0039-6028},
  keyword      = {Graphene,Bilayer,Hydrogenation,Li,LEEM,PES,LEED,ARPES},
  language     = {eng},
  number       = {3-4},
  pages        = {401--406},
  publisher    = {Elsevier},
  series       = {Surface Science},
  title        = {Studies of Li intercalation of hydrogenated graphene on SiC(0001)},
  url          = {http://dx.doi.org/10.1016/j.susc.2011.10.023},
  volume       = {606},
  year         = {2012},
}