This letter presents a graphene field effect transistor (GFET) nanosensor that, with a solid gate provided by a high-κ dielectric, allows analyte detection in liquid media at low gate voltages. The gate is embedded within the sensor and thus is isolated from a sample solution, offering a high level of integration and miniaturization and eliminating errors caused by the liquid disturbance, desirable for both in vitro and in vivo applications. We demonstrate that the GFET nanosensor can be used to measure pH changes in a range of 5.3–9.3. Based on the experimental observations and quantitative analysis, the charging of an electrical double layer capacitor is found to be the major mechanism of pH sensing.

1.
Z. G.
Cheng
,
Q.
Li
,
Z. J.
Li
,
Q. Y.
Zhou
, and
Y.
Fang
,
Nano Lett.
10
(
5
),
1864
(
2010
).
2.
W. G.
Xu
,
X.
Ling
,
J. Q.
Xiao
,
M. S.
Dresselhaus
,
J.
Kong
,
H. X.
Xu
,
Z. F.
Liu
, and
J.
Zhang
,
Proc. Natl. Acad. Sci. U. S. A.
109
(
24
),
9281
(
2012
).
3.
X. H.
Kang
,
J.
Wang
,
H.
Wu
,
J.
Liu
,
I. A.
Aksay
, and
Y. H.
Lin
,
Talanta
81
(
3
),
754
(
2010
).
4.
B.
Unnikrishnan
,
S.
Palanisamy
, and
S. M.
Chen
,
Biosens. Bioelectron.
39
(
1
),
70
(
2013
).
5.
Y.
Ohno
,
K.
Maehashi
,
Y.
Yamashiro
, and
K.
Matsumoto
,
Nano Lett.
9
(
9
),
3318
(
2009
).
6.
Y.
Ohno
,
S.
Okamoto
,
K.
Maehashi
, and
K.
Matsumoto
,
Jpn. J. Appl. Phys., Part 1
52
(
11
),
110107
(
2013
).
7.
K.
Maehashi
,
Y.
Sofue
,
S.
Okamoto
,
Y.
Ohno
,
K.
Inoue
, and
K.
Matsumoto
,
Sens. Actuators, B
187
,
45
(
2013
).
8.
S.
Mao
,
G. H.
Lu
,
K. H.
Yu
,
Z.
Bo
, and
J. H.
Chen
,
Adv. Mater.
22
(
32
),
3521
(
2010
).
9.
F.
Schwierz
,
Nat. Nanotechnol.
5
(
7
),
487
(
2010
).
10.
W. J.
Yuan
and
G. Q.
Shi
,
J. Mater. Chem. A
1
(
35
),
10078
(
2013
).
11.
B. J.
Kim
,
H.
Jang
,
S. K.
Lee
,
B. H.
Hong
,
J. H.
Ahn
, and
J. H.
Cho
,
Nano Lett.
10
(
9
),
3464
(
2010
).
12.
J. H.
Chen
,
C.
Jang
,
S.
Adam
,
M. S.
Fuhrer
,
E. D.
Williams
, and
M.
Ishigami
,
Nat. Phys.
4
(
5
),
377
(
2008
).
13.
See supplementary material at http://dx.doi.org/10.1063/1.4916341 for further details of fabrication and measurements.
14.
15.
J. R.
Williams
,
T.
Low
,
M. S.
Lundstrom
, and
C. M.
Marcus
,
Nat. Nanotechnol.
6
(
4
),
222
(
2011
).
16.
J. L.
Xia
,
F.
Chen
,
P.
Wiktor
,
D. K.
Ferry
, and
N. J.
Tao
,
Nano Lett.
10
(
12
),
5060
(
2010
).
17.
B.
Mailly-Giacchetti
,
A.
Hsu
,
H.
Wang
,
V.
Vinciguerra
,
F.
Pappalardo
,
L.
Occhipinti
,
E.
Guidetti
,
S.
Coffa
,
J.
Kong
, and
T.
Palacios
,
J. Appl. Phys.
114
(
8
),
084505
(
2013
).
18.
A. S.
Feiner
and
A. J.
Mcevoy
,
J. Chem. Educ.
71
(
6
),
493
(
1994
).
19.
S.
Kim
,
J.
Nah
,
I.
Jo
,
D.
Shahrjerdi
,
L.
Colombo
,
Z.
Yao
,
E.
Tutuc
, and
S. K.
Banerjee
,
Appl. Phys. Lett.
94
(
6
),
062107
(
2009
).
20.
I.
Meric
,
M. Y.
Han
,
A. F.
Young
,
B.
Ozyilmaz
,
P.
Kim
, and
K. L.
Shepard
,
Nat. Nanotechnol.
3
(
11
),
654
(
2008
).
21.
J. L.
Xia
,
F.
Chen
,
J. H.
Li
, and
N. J.
Tao
,
Nat. Nanotechnol.
4
(
8
),
505
(
2009
).
22.
I.
Heller
,
S.
Chatoor
,
J.
Mannik
,
M. A. G.
Zevenbergen
,
C.
Dekker
, and
S. G.
Lemay
,
J. Am. Chem. Soc.
132
(
48
),
17149
(
2010
).
23.
H. M.
Wang
,
Y. H.
Wu
,
C. X.
Cong
,
J. Z.
Shang
, and
T.
Yu
,
ACS Nano
4
(
12
),
7221
(
2010
).

Supplementary Material

You do not currently have access to this content.