When
you write with a pencil, you are using a form of nanotechnology. The graphite
commonly known as “pencil lead” is the purest form of carbon. It is composed
of ultra-thin sheets of carbon atoms, made of hexagonal patterns of atoms known
as benzene rings.
As
you press down on the pencil to write, those sheets slide against one another
and adhere to the page. Most of the marks you make consist of millions of
those sheets stacked on top of one another. They are held loosely together by
the forces among the molecules, known as van der Waals forces.
But
a few of the flakes slide off as individual sheets, a single atom in
thickness. Those sheets, the thinnest substance in the universe, are known as graphene.
And according to an article in Scientific American,1 they are exciting physicists and
engineers the world over.
At
a recent meeting of the American Physical Society, more than 100 papers on
graphene were presented. And according to The New York Times,2 the house was packed.
The
laboratory quest to make and understand graphene has been going on for less
than a decade. Until 2004, researchers had only been able to cleave layers of
graphene about 10 atoms thick using high-tech tools, such as atomic force
microscopes. Then, a researcher at the University of Manchester placed
graphite on ordinary Scotch tape and folded it over. Pulling it apart split
the flake in two. By doing this repeatedly, he was able to make the graphite
thinner and thinner. Then he stuck the tape to a silicon wafer and successfully
rubbed off flakes of graphene just one atom thick.
Ironically,
graphene is the basic component from which all other carbon nanomaterials are
made. For example, buckyballs are assembled out of graphene sheets. A carbon
nanotube is a graphene sheet rolled into a cylinder.
Already,
scientists at the School of Physics and Astronomy (University of Manchester)
have reported in Science3 that they were able to create the world’s smallest transistor with graphene — a
mere one atom thick and ten atoms wide.
Previous
attempts to build transistors smaller than 10 nanometers have failed because
quantum effects...
