Chemistry Reference
In-Depth Information
not equal in our measurements, indicating that noise minimum has been
shifted away from charge neutrality in the presence of finite
.Morede-
tailed analysis shows that multiple processes involving the charge traps are
active in producing the resistance noise which is intimately connected to
the BLG band structure, being minimum at ∆
g
∼
E
0 even if it corresponds
.
45
to a nonzero
n
4. Conclusion
In summary, we have done a comparative study of low frequency fluctu-
ations in electrical resistance of graphene based field-effect devices with
varying layer thickness. An analytical model of noise has been proposed
based on the number fluctuation between the interfacial oxide traps and
the correlated mobility fluctuation. Gate voltage dependence of noise in
various graphene devices can well be explained using our model, showing
its intimate connection to the bandstructure. Apart from opposite gate
voltage characteristics between multilayer graphene and SLG, a striking
observation in this study is the extremely low magnitude of noise in case
of multilayer graphene, with Hooge parameter as low as 10
−
6
at low tem-
peratures. This makes few/multilayer graphene an attractive candidate for
future nanoelectronics. Also, we have measured the low-frequency resis-
tance noise in bilayer graphene flakes as a function of charge density and
inter-electrode electric field. The absolute magnitude of noise is intimately
connected with the BLG band structure, and shows a minimum when the
band gap of the system is zero. The experiments also reveal the charge orga-
nization in BLG-based electronic devices, and the microscopic mechanism
of resistance noise.
Acknowledgments
We acknowledge the Department of Science and Technology (DST) for a
funded project, and the Institute Nanoscience Initiative, Indian Institute
of Science, for infrastructural support.
ANP thanks CSIR for financial
support.
References
1. K.S.Novoselov,A.K.Geim,S.V.Morozov,D.Jiang,Y.Zhang,S.V.
Dubonos, I. V. Grigorieva, and A. A. Firsov,
Science
306
, 666 (2004).
