Researchers from the University of Southern California (USC)
and the National Institute of Standards and Technology (NIST) have demonstrated
a technique for growing virtually pure samples of single-wall carbon nanotubes
(SWCNTs) with identical structures, a process they liken to "cloning"
the nanotubes.* If it can be suitably scaled up, their approach could solve an
important materials problem in nanoelectronics: producing carbon nanotubes of a
specific structure to order.
Single-wall carbon nanotubes are hollow cylinders of carbon
atoms bound together in a hexagonal pattern, usually about a nanometer in
diameter. One fascinating feature of nanotubes is that there are many ways to
wrap the hexagon sheet into a cylinder, from perfectly even rows of hexagons
that wrap around in a ring, to rows that wrap in spirals at various
angles—"chiralities," to be technical. Even more interesting,
chirality is critical to the electronic properties of carbon nanotubes. Some
structures are electrical conductors—essentially a nanoscale wire—others are
semiconductors.