Alessandra Lanzara talks with
ScienceWatch.com and answers a few questions about
this month's Fast Breaking Paper in the field of Materials
Article Title: Substrate-induced bandgap opening in
Authors: Zhou, SY;Gweon, GH;Fedorov, AV;First, PN;De Heer,
WA;Lee, DH;Guinea, F;Neto,
Journal: NAT MATER
Year: OCT 2007
* Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720
(addresses have been truncated)
Why do you think your paper is highly
Graphene, a single layer of carbon atoms arranged in a honeycomb lattice,
has shown great application potential as a host material for
next-generation electronic devices, with properties that may exceed current
silicon-based technology. For example, electrons in graphene can move 100
times faster than those in silicon. However, despite its intriguing
properties, graphene is a zero-gap semiconductor, which limits its
Therefore, how to engineer graphene in order to have a finite bandgap is an
important issue that needs to be resolved. Although several approaches have
been proposed so far, each one requires complex engineering of the graphene
sheet down to a few nanometers and hence, a low reproducibility rate. Our
work proposes a novel and relatively easy way to induce a finite bandgap in
graphene by epitaxially growing graphene on a substrate.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
Although the epitaxial growth of graphene was studied previously, our work
is the first one to show how one can use the graphene/substrate interaction
to induce a finite bandgap in the graphene spectra. This provides a much
easier method to induce a bandgap in a large epitaxial graphene sample
without requiring the complicated engineering of graphene nanostructures.
Would you summarize the significance of your paper in
Our study points out that graphene-substrate interaction can be an
effective way of engineering the bandgap in graphene, and also suggests
that, by growing graphene on different substrates, tuning of the bandgap in
a large range could possibly be achieved.
How did you become involved in this research, and were
there any problems along the way?
I have been working on high-temperature superconductors for 10 years. It is
an intriguing system which shares many similarities in its fundamental
electronic structure with that of graphene.
When Shuyun Zhou joined my group in 2002 for her Ph.D., she immediately
realized the potential of carbon materials and how they could be used to
help us understand several of the still obscure aspects of the physics of
She soon became involved working with graphite—an infinite stack of
graphene layers—as graphene had not been discovered at that time.
With her enthusiasm and determination, she brought significant and novel
contributions to a field which, in some ways, was thought of as
Soon thereafter, graphene was discovered and we both were quite prepared to
expand the parameters of our previous research so as to include this
emerging field. The extensive application potential of graphene was another
important factor which had attracted us immediately to its study and also
led to the idea of how to engineer graphene in order to tune a finite
bandgap in its electronic spectra.
Where do you see your research leading in the
Graphene is a new emerging material which has the potential to marry the
high-quality performance of our best semiconductors to the novel
functionality of our best nanostructures, thus promising revolutionary new
applications that span a broad range of technologies and have the potential
to change our world.
Because of this, my research group is currently involved in several aspects
of the physics of graphene: from exploring new ways of synthesizing
graphene on a desired substrate, which will also allow a more targeted
control on the engineering of the gap, using graphene engineered with
magnetic systems for spintronics applications, and to combine graphene with
other materials in order to generate high-strength materials and new
systems for use in alternative energy.
Do you foresee any social or political implications for
I hope that, with more research activities turning toward graphene bandgap
engineering, we can eventually achieve a finer control of semiconducting
graphene with a bandgap tunable in a large energy range. This should
eventually make graphene quite useful in the manufacture of electronic
devices and also in the making of solar cells.
Professor Alessandra Lanzara
Department of Physics
University of California Berkeley
Berkeley, CA, USA
Keywords: graphene, graphene sheet, a single layer of carbon
atoms arranged in a honeycomb lattice, host material for next-generation
electronic devices, silicon-based technology, finite bandgap, graphene
substrate interaction, epitaxially growing graphene on a substrate,
graphene nanostructures, graphene-substrate interaction, physics of