Semiconducting carbon nanotubes could be the centerpiece of low-
power, ultra-fast electronics of the future. The challenge is
getting them to work with today’s manufacturing processes. Now
researchers at Stanford University have made an important
advance toward large-scale nanotube electronics. They have
created functional transistors using an etching process that can
be integrated with the methods used to carve out silicon-based
computer chips. A major roadblock to making carbon-nanotube
transistors has been the difficulty of separating semiconducting
tubes from a typical batch of nanotubes, in which about a third
of the material is metallic. Even a tiny percentage of metallic
tubes would short a device, causing it to fail. The established
but tricky approach to making transistors involves separating
out semiconducting nanotubes and then arranging them into
circuits. Hongjie Dai and his colleagues take a new approach.
They grow a mixed bunch of semiconducting and metallic nanotubes
on a silicon wafer and hav