Vacuum-ultraviolet light irradiation under a high vacuum is a facile method to reduce graphene oxide (GO) sheets and therefore to enhance their electrical conductivity. The aim of this study was to investigate the local electrical properties of a reduced graphene oxide (rGO) monolayer and bilayer by using conductive atomic force microscopy (CAFM). Both the lateral and vertical CAFM measurements showed a higher current signal on the rGO bilayer than on the rGO monolayer. The enlargement of the tip contact area significantly affected the vertical CAFM measurements and enhanced the current signal in the bilayer regions. However, when performing the lateral CAFM measurements, the enlarged tip contact area had no obvious influence on the current signal. The increase in the current signal can be ascribed to the intrinsic enhancement of the electrical conductivity on the rGO bilayer. These results suggested that the stacked rGO sheets formed the new conductive paths for the carrier transportation in the lateral direction. This process can be further applied in producing microconductive patterns in multilayered GO.

1.
S.
Park
and
R. S.
Ruoff
,
Nat. Nanotechnol.
4
,
217
(
2009
).
2.
D. R.
Dreyer
,
S.
Park
,
C. W.
Bielawski
, and
R. S.
Ruoff
,
Chem. Soc. Rev.
39
,
228
(
2010
).
3.
Y.
Zhu
,
D. K.
James
, and
J. M.
Tour
,
Adv. Mater.
24
,
4924
(
2012
).
4.
S.
Pei
and
H.-M. M.
Cheng
,
Carbon
50
,
3210
(
2012
).
5.
Y. L.
Zhang
,
L.
Guo
,
H.
Xia
,
Q. D.
Chen
,
J.
Feng
, and
H. B.
Sun
,
Adv. Opt. Mater.
2
,
10
(
2014
).
6.
V. A.
Smirnov
,
A. A.
Arbuzov
,
Y. M.
Shul'ga
,
S. A.
Baskakov
,
V. M.
Martynenko
,
V. E.
Muradyan
, and
E. I.
Kresova
,
High Energy Chem.
45
,
57
(
2011
).
7.
Y.
Tu
,
T.
Ichii
,
O. P.
Khatri
, and
H.
Sugimura
,
Appl. Phys. Express
7
,
75101
(
2014
).
8.
A.
Schreiber
,
B.
Kühn
,
E.
Arnold
,
F.-J.
Schilling
, and
H.-D.
Witzke
,
J. Phys. D: Appl. Phys.
38
,
3242
(
2005
).
9.
Y.
Tu
,
T.
Ichii
,
T.
Utsunomiya
, and
H.
Sugimura
,
Appl. Phys. Lett.
106
,
133105
(
2015
).
10.
J. M.
Mativetsky
,
E.
Treossi
,
E.
Orgiu
,
M.
Melucci
,
G. P.
Veronese
,
P.
Samorì
,
V.
Palermo
,
P.
Samorì
, and
V.
Palermo
,
J. Am. Chem. Soc.
132
,
14130
(
2010
).
11.
Y.
Kanamori
,
S.
Obata
, and
K.
Saiki
,
Chem. Lett.
40
,
255
(
2011
).
12.
Y.
Zhu
,
W.
Cai
,
R. D.
Piner
,
A.
Velamakanni
, and
R. S.
Ruoff
,
Appl. Phys. Lett.
95
,
103104
(
2009
).
13.
B. L. M.
Hendriksen
 et al,
Nano Lett.
11
,
4107
(
2011
).
14.
R. R.
Nair
,
P.
Blake
,
A. N.
Grigorenko
,
K. S.
Novoselov
,
T. J.
Booth
,
T.
Stauber
,
N. M. R.
Peres
, and
A. K.
Geim
,
Science
320
,
1308
(
2008
).
15.
J. O.
Hwang
 et al,
ACS Nano
6
,
159
(
2012
).
16.
H. A.
Becerril
,
J.
Mao
,
Z.
Liu
,
R. M.
Stoltenberg
,
Z.
Bao
, and
Y.
Chen
,
ACS Nano
2
,
463
(
2008
).
17.
H.
Hwang
,
P.
Joo
,
M. S.
Kang
,
G.
Ahn
,
J. T.
Han
,
B. S.
Kim
, and
J. H.
Cho
,
ACS Nano
6
,
2432
(
2012
).
18.
M.
Hirata
,
T.
Gotou
,
S.
Horiuchi
,
M.
Fujiwara
, and
M.
Ohba
,
Carbon
42
,
2929
(
2004
).
19.
Y.
Tu
,
T.
Utsunomiya
,
T.
Ichii
, and
H.
Sugimura
,
ACS Appl. Mater. Interfaces
8
,
10627
(
2016
).
20.
H.
Sano
,
T.
Yaku
,
T.
Ichii
,
K.
Murase
, and
H.
Sugimura
,
J. Vac. Sci. Technol., B
27
,
858
(
2009
).
21.
Y.
Yamada
,
H.
Yasuda
,
K.
Murota
,
M.
Nakamura
,
T.
Sodesawa
, and
S.
Sato
,
J. Mater. Sci.
48
,
8171
(
2013
).
22.
C.-C.
Teng
,
C.-C. M.
Ma
,
C.-H.
Lu
,
S.-Y.
Yang
,
S.-H.
Lee
,
M.-C.
Hsiao
,
M.-Y.
Yen
,
K.-C.
Chiou
, and
T.-M.
Lee
,
Carbon
49
,
5107
(
2011
).
23.
K. N.
Kudin
,
B.
Ozbas
,
H. C.
Schniepp
,
R. K.
Prud'homme
,
I. A.
Aksay
, and
R.
Car
,
Nano Lett.
8
,
36
(
2008
).
24.
A. C.
Ferrari
and
D. M.
Basko
,
Nat. Nanotechnol.
8
,
235
(
2013
).
25.
L. G.
Cançado
 et al,
Nano Lett.
11
,
3190
(
2011
).
26.
H. P.
Mungse
,
Y.
Tu
,
T.
Ichii
,
T.
Utsunomiya
,
H.
Sugimura
, and
O. P.
Khatri
,
Adv. Mater. Interfaces
3
,
1500410
(
2016
).
27.
K. L.
Johnson
,
Contact Mechanics
(
Cambridge University
,
Cambridge
,
1987
).
28.
J. I.
Paredes
,
S.
Villar-Rodil
,
P.
Solís-Fernández
,
A.
Martínez-Alonso
, and
J. M. D.
Tascón
,
Langmuir
25
,
5957
(
2009
).
29.
C.
Gómez-Navarro
,
J. C.
Meyer
,
R. S.
Sundaram
,
A.
Chuvilin
,
S.
Kurasch
,
M.
Burghard
,
K.
Kern
, and
U.
Kaiser
,
Nano Lett.
10
,
1144
(
2010
).
30.
C.
Gómez-Navarro
,
R. T.
Weitz
,
A. M.
Bittner
,
M.
Scolari
,
A.
Mews
,
M.
Burghard
, and
K.
Kern
,
Nano Lett.
7
,
3499
(
2007
).
31.
H. E.
Romero
,
N.
Shen
,
P.
Joshi
,
H. R.
Gutierrez
,
S. A.
Tadigadapa
,
J. O.
Sofo
, and
P. C.
Eklund
,
ACS Nano
2
,
2037
(
2008
).
32.
J. S.
Bunch
,
S. S.
Verbridge
,
J. S.
Alden
,
A. M.
Van Der Zande
,
J. M.
Parpia
,
H. G.
Craighead
, and
P. L.
McEuen
,
Nano Lett.
8
,
2458
(
2008
).
33.
M. F.
El-Kady
,
V.
Strong
,
S.
Dubin
, and
R. B.
Kaner
,
Science
335
,
1326
(
2012
).
34.
L. J.
Cote
,
R.
Cruz-Silva
, and
J.
Huang
,
J. Am. Chem. Soc.
131
,
11027
(
2009
).
35.
Y.
Matsumoto
,
M.
Koinuma
,
S. Y.
Kim
,
Y.
Watanabe
,
T.
Taniguchi
,
K.
Hatakeyama
,
H.
Tateishi
, and
S.
Ida
,
ACS Appl. Mater. Interfaces
2
,
3461
(
2010
).
36.
Y.
Zhang
,
L.
Guo
,
S.
Wei
,
Y.
He
,
H.
Xia
,
Q.
Chen
,
H.-B. B.
Sun
, and
F.-S. S.
Xiao
,
Nano Today
5
,
15
(
2010
).
37.
See supplementary material at http://dx.doi.org/10.1116/1.4982722 for (a) estimation of the mechanical tip contact area on rGO monolayer, (b) two-dimensional triangle model, (c) electrical conductivity of rGO patterns.

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