Summary: Physicists Show Electrons Can Travel More Than 100 Times
Faster in Graphene
Michael S. Fuhrer
University of Maryland physicists have shown that in graphene the intrinsic limit to the mobility, a measure of how well a
material conducts electricity, is higher than any other known material at room temperature. Graphene, a single-atom-thick
sheet of graphite, is a new material which combines aspects of semiconductors and metals.
Their results, published online in the journal Nature Nanotechnology, indicate that graphene holds great promise for
replacing conventional semiconductor materials such as silicon in applications ranging from high-speed computer chips to
An optical microscope image of the graphene device.The yellow parts are gold electrodes, the slightly darker purple area is
the graphene, and the lighter purple is the bare SiO2/Si substrate.
A team of researchers led by physics professor Michael S. Fuhrer of the university's Center for Nanophysics and Advanced
Materials, and the Maryland NanoCenter said the findings are the first measurement of the effect of thermal vibrations on
the conduction of electrons in graphene, and show that thermal vibrations have an extraordinarily small effect on the
electrons in graphene.
In any material, the energy associated with the temperature of the material causes the atoms of the material to vibrate in
place. As electrons travel through the material, they can bounce off these vibrating atoms, giving rise to electrical resistance.
This electrical resistance is 'intrinsic' to the material: it cannot be eliminated unless the material is cooled to absolute zero
temperature, and hence sets the upper limit to how well a material can conduct electricity.
In graphene, the vibrating atoms at room temperature produce a resistivity of about 1.0 microOhm-cm (resistivity is a