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Layer-number determination in graphene on SiC by reflectance mapping

Ivanov, Ivan G.; Hassan, Jawad Ul; Iakimov, Tihomir; Zakharov, Alexei LU ; Yakimova, Rositsa and Janzen, Erik (2014) In Carbon 77. p.492-500
Abstract
We report a simple, handy and affordable optical approach for precise number-of-layers determination of graphene on SiC based on monitoring the power of the laser beam reflected from the sample (reflectance mapping) in a slightly modified micro-Raman setup. Reflectance mapping is compatible with simultaneous Raman mapping. We find experimentally that the reflectance of graphene on SiC normalized to the reflectivity of bare substrate (the contrast) increases linearly with similar to 1.7% per layer for up to 12 layers, in agreement with theory The wavelength dependence of the contrast in the visible is investigated using the concept of ideal fermions and compared with existing experimental data for the optical constants of graphene. We argue... (More)
We report a simple, handy and affordable optical approach for precise number-of-layers determination of graphene on SiC based on monitoring the power of the laser beam reflected from the sample (reflectance mapping) in a slightly modified micro-Raman setup. Reflectance mapping is compatible with simultaneous Raman mapping. We find experimentally that the reflectance of graphene on SiC normalized to the reflectivity of bare substrate (the contrast) increases linearly with similar to 1.7% per layer for up to 12 layers, in agreement with theory The wavelength dependence of the contrast in the visible is investigated using the concept of ideal fermions and compared with existing experimental data for the optical constants of graphene. We argue also that the observed contrast is insensitive to the doping condition of the sample, as well as to the type of sample (graphene on C- or Si-face of 4H or 6H SiC, hydrogen-intercalated graphene). The possibility to extend the precise layer counting to similar to 50 layers makes reflectivity mapping superior to low-energy electron microscopy (limited to similar to 10 layers) in quantitative evaluation of graphene on the C-face of SiC. The method is applicable for graphene on other insulating or semiconducting substrates. (C) 2014 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Carbon
volume
77
pages
492 - 500
publisher
Elsevier
external identifiers
  • wos:000340689400054
  • scopus:84905643934
ISSN
0008-6223
DOI
10.1016/j.carbon.2014.05.054
language
English
LU publication?
yes
id
df656503-319c-4a54-9931-ab5a83873efd (old id 4648830)
date added to LUP
2014-09-24 08:16:21
date last changed
2017-09-03 03:16:35
@article{df656503-319c-4a54-9931-ab5a83873efd,
  abstract     = {We report a simple, handy and affordable optical approach for precise number-of-layers determination of graphene on SiC based on monitoring the power of the laser beam reflected from the sample (reflectance mapping) in a slightly modified micro-Raman setup. Reflectance mapping is compatible with simultaneous Raman mapping. We find experimentally that the reflectance of graphene on SiC normalized to the reflectivity of bare substrate (the contrast) increases linearly with similar to 1.7% per layer for up to 12 layers, in agreement with theory The wavelength dependence of the contrast in the visible is investigated using the concept of ideal fermions and compared with existing experimental data for the optical constants of graphene. We argue also that the observed contrast is insensitive to the doping condition of the sample, as well as to the type of sample (graphene on C- or Si-face of 4H or 6H SiC, hydrogen-intercalated graphene). The possibility to extend the precise layer counting to similar to 50 layers makes reflectivity mapping superior to low-energy electron microscopy (limited to similar to 10 layers) in quantitative evaluation of graphene on the C-face of SiC. The method is applicable for graphene on other insulating or semiconducting substrates. (C) 2014 Elsevier Ltd. All rights reserved.},
  author       = {Ivanov, Ivan G. and Hassan, Jawad Ul and Iakimov, Tihomir and Zakharov, Alexei and Yakimova, Rositsa and Janzen, Erik},
  issn         = {0008-6223},
  language     = {eng},
  pages        = {492--500},
  publisher    = {Elsevier},
  series       = {Carbon},
  title        = {Layer-number determination in graphene on SiC by reflectance mapping},
  url          = {http://dx.doi.org/10.1016/j.carbon.2014.05.054},
  volume       = {77},
  year         = {2014},
}