Activity Report 2010 - CNRS

SCIENTIFIC REPORT
FURTHER READING:
J. Phys. D: Appl. Phys. 43 374008 (2010)
Interface structure of graphene on SiC : an
ab initio and STM approach
Fig. 2: Silicium nanowires used for
photoluminescence studies (the scale marker
equals 10 μm)
Please read the corresponding Highlight
at the end of this report for further
information
Graphene
RTRA Project 2008 : “Graphene : from
materials to test devices ”
Coordinator: Laurence MAGAUD (Institut
Néel)
Post-doctoral Fellow: Vincent RENARD
Since 2005, interest in graphene has
been growing among condensed matter
physicists, due to exceptional
fundamental properties, promising a high
potential for the development of future
nanoelectronics. As silicon reaches its
limits, it becomes crucial to find new
alternative materials and graphene is a
very serious candidate for that purpose.
Fig. 3: Graphene on the C-face of SiC
observed by AFM (sample grown in LMGP)
Finally the team has modelled the effect
of ripples in quantum transport
calculations for both zigzag (ZGNR) and
armchair (AGNR) graphene nanoribbons
and extracted relevant physical quantities
such as band structure, conductance and
mobility of nanoribbons with different
lateral width.
In that purpose, the active part of the
device is defined either by an armchair or
a zigzag graphene nanoribbon of length
≈ 20 nm, for the simulation of a realistic
device. An example of the simulated
ripples is shown in Figure 4 for the case
of 1D and 2D ripples.
The RTRA project “DISPOGRAPH” aims to
unify the community in Grenoble and to
design devices based on the unique
properties of this material.
An original endeavour focused on the
elaboration of graphene led to a new
synthesis method on SiC carbon face -
instead of the commonly used silicon
face. Thick layers of graphene were
obtained and characterized by Raman
spectroscopy and AFM. (Fig. 3)
Thin films obtained under ultrahigh
vacuum were characterized by STM,
showing in this case a weak coupling
between graphene and the substrate, and
thus the formation of a quasi-ideal layer
graphene. Magneto transport
measurements at low temperatures also
show a weak anti-localization in
agreement with the theory WAL.
Fig.4: Examples of nanoribbons with 1D
ripples (up) and 2D ripples (down).
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