Chemistry Reference
In-Depth Information
V
D
is the backgate voltage at CNP. Figure 2(b) clearly
demonstrates the ambipolar transistor action in all devices, although the
effect of gating decreases with increasing layer numbers. Mobility of SLG,
BLG, FLG, and MLG devices was calculated to be 1100
,
1160
,
2450
,
and
1200 cm
2
V
−
1
s
−
1
respectively.
V
bg
− V
D
), where
(
(a)
(b)
(c)
(d)
Fig. 3. The resistance and the normalized noise power spectral density (
N
R
) as func-
tions of back gate voltages are shown for: (a) SLG (b) BLG (c) FLG and (d) MLG
devices at T = 100 K. The thick solid lines are guide to the eye. The insets in each fig-
ure correspond to the bandstructure at particular voltages for corresponding graphene
flake.
3.2.
Noise characteristics in graphene based FET devices
Noise in the graphene devices were measured in low frequency ac four-probe
method.
57
In all devices, the normalized resistance noise PSD behaved
α
,with
as
2.
45
Here, instead
of focusing on noise magnitude at a specific frequency, we compute and
S
R
(
f
)
/R
2
∼
1
/f
α
ranging from 0
.
8
−
1
.
