Chemistry Reference
In-Depth Information
Chapter 13
Noise in Graphene Transistors
Atindra Nath Pal
∗
and Arindam Ghosh
†
Department of Physics, Indian Institute of Science,
Bangalore 560 012, India
∗
atin@physics.iisc.ernet.in
†
arindam@physics.iisc.ernet.in
Graphene, single atomic layer of hexagonal carbon atoms, has drawn
a lot of interest because of its unusual electronic properties. As an
emerging new material, an investigation of the effect of time dependent
disorder of graphene devices is hence necessary for both application and
fundamental understanding. Here, we present a systematic study of low-
frequency noise in graphene-based field-effect transistors with varying
number of layers. In single-layer devices, the noise magnitude decreases
with increasing carrier density, which behaved oppositely in the devices
with two or larger number of layers. We have developed a theoretical
model of noise based on a correlated number and mobility fluctuations
due to the underlying traps inside SiO
2
substrate. We show that the
variation of noise with carrier density is opposite for linear and parabolic
band structure, and hence can act as a sensitive transport-based tool to
separate single layer graphene from others.
1. Introduction
Graphene, a single sheet of carbon atoms, has become a potential candidate
for future electronics.
1-6
It is the thinnest available material in the world
and the strongest
7
ever measured. Its charge carriers have the zero effective
mass and can travel micrometer-long distances without scattering at room
temperature. Carrier mobilities as high as 1
×
10
4
cm
2
/Vs are now obtained
on SiO
2
10
5
cm
2
/Vs) in
suspended graphene.
9-11
Graphene can sustain 2 orders higher current
densities than copper,
12
shows record thermal conductivity
13
and stiff-
ness. Electron transport in graphene is described by a Dirac-like equation,
substrate,
8
which is considerably enhanced (2
×
199
