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Multi-scale investigation of interface properties, stacking order and decoupling of few layer graphene on C-face 4H-SiC

Bouhafs, C.; Zakharov, A. A. LU ; Ivanov, Ivan G.; Giannazzo, F.; Eriksson, J.; Stanishev, V.; Kühne, P.; Iakimov, T.; Hofmann, T. and Schubert, M., et al. (2017) In Carbon 116. p.722-732
Abstract

In this work, we report a multi-scale investigation using several nano-, micro and macro-scale techniques of few layer graphene (FLG) sample consisting of large monolayer (ML) and bilayer (BL) areas grown on C-face 4H-SiC (000-1) by high-temperature sublimation. Single 1 × 1 diffraction patterns are observed by micro-low-energy electron diffraction for ML, BL and trilayer graphene with no indication of out-of-plane rotational disorder. A SiOx layer is identified between graphene and SiC by X-ray photoelectron emission spectroscopy and reflectance measurements. The chemical composition of the interface layer changes towards SiO2 and its thickness increases with aging in normal ambient conditions. The formation... (More)

In this work, we report a multi-scale investigation using several nano-, micro and macro-scale techniques of few layer graphene (FLG) sample consisting of large monolayer (ML) and bilayer (BL) areas grown on C-face 4H-SiC (000-1) by high-temperature sublimation. Single 1 × 1 diffraction patterns are observed by micro-low-energy electron diffraction for ML, BL and trilayer graphene with no indication of out-of-plane rotational disorder. A SiOx layer is identified between graphene and SiC by X-ray photoelectron emission spectroscopy and reflectance measurements. The chemical composition of the interface layer changes towards SiO2 and its thickness increases with aging in normal ambient conditions. The formation mechanism of the interface layer is discussed. It is shown by torsion resonance conductive atomic force microscopy that the interface layer causes the formation of non-ideal Schottky contact between ML graphene and SiC. This is attributed to the presence of a large density of interface states. Mid-infrared optical Hall effect measurements revealed Landau-level transitions in FLG that have a square-root dependence on magnetic field, which evidences a stack of decoupled graphene sheets. Contrary to previous works on decoupled C-face graphene, our BL and FLG are composed of ordered decoupled graphene layers without out-of-plane rotation.

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publication status
published
subject
in
Carbon
volume
116
pages
11 pages
publisher
Elsevier
external identifiers
  • scopus:85013805277
  • wos:000397549300083
ISSN
0008-6223
DOI
10.1016/j.carbon.2017.02.026
language
English
LU publication?
yes
id
9e35de48-bdf9-437b-8ec9-0515f44fc9a7
date added to LUP
2017-03-08 08:57:05
date last changed
2017-09-18 11:37:53
@article{9e35de48-bdf9-437b-8ec9-0515f44fc9a7,
  abstract     = {<p>In this work, we report a multi-scale investigation using several nano-, micro and macro-scale techniques of few layer graphene (FLG) sample consisting of large monolayer (ML) and bilayer (BL) areas grown on C-face 4H-SiC (000-1) by high-temperature sublimation. Single 1 × 1 diffraction patterns are observed by micro-low-energy electron diffraction for ML, BL and trilayer graphene with no indication of out-of-plane rotational disorder. A SiO<sub>x</sub> layer is identified between graphene and SiC by X-ray photoelectron emission spectroscopy and reflectance measurements. The chemical composition of the interface layer changes towards SiO<sub>2</sub> and its thickness increases with aging in normal ambient conditions. The formation mechanism of the interface layer is discussed. It is shown by torsion resonance conductive atomic force microscopy that the interface layer causes the formation of non-ideal Schottky contact between ML graphene and SiC. This is attributed to the presence of a large density of interface states. Mid-infrared optical Hall effect measurements revealed Landau-level transitions in FLG that have a square-root dependence on magnetic field, which evidences a stack of decoupled graphene sheets. Contrary to previous works on decoupled C-face graphene, our BL and FLG are composed of ordered decoupled graphene layers without out-of-plane rotation.</p>},
  author       = {Bouhafs, C. and Zakharov, A. A. and Ivanov, Ivan G. and Giannazzo, F. and Eriksson, J. and Stanishev, V. and Kühne, P. and Iakimov, T. and Hofmann, T. and Schubert, M. and Roccaforte, F. and Yakimova, R and Darakchieva, V.},
  issn         = {0008-6223},
  language     = {eng},
  month        = {05},
  pages        = {722--732},
  publisher    = {Elsevier},
  series       = {Carbon},
  title        = {Multi-scale investigation of interface properties, stacking order and decoupling of few layer graphene on C-face 4H-SiC},
  url          = {http://dx.doi.org/10.1016/j.carbon.2017.02.026},
  volume       = {116},
  year         = {2017},
}