Silicon's successor lurks in the lab
Published: 20 Oct 2003 16:05 BST
Silicon strikes back
In the end, silicon compatibility could tip the balance toward silicon nanowires.
Silicon nanowires are made by siphoning molecules of SiH4 (a single silicon atom surrounded by four hydrogen atoms) through a gold particle, said Andre DeHon, a professor at the California Institute of Technology. The gold strips off the hydrogen atoms and allows the naked silicon atoms to form into a wire.
"Our goal is to build interesting-size memories out of these things," he said at the Hot Chips industry conference in August. "This is something that could come through in single-digit years -- three to five years, if someone really wanted to push it."
As futuristic as it sounds, the technique was first described by researchers at Bell Labs in 1964.
Although nanowires may not exhibit the same electrical properties as nanotubes, silicon nanowires may be easier to grow on the wafer itself, DeHon added. Nonetheless, the process cannot be done overnight.
"It will be a number of years before we see a change," said Pat Gelsinger, chief technology officer at Intel, which is working with university researchers on both approaches. "It is preliminary to say it is either one."
Despite the challenges, researchers and companies are optimistic about nanotubes, buoyed by positive experimental results that are occurring at a fairly rapid pace.
"We have made enormous progress," Appenzeller said. "Everything is working out so far fine." What makes researchers giddy about nanotubes? Here are some of their properties and how they could be used.
Ballistic transport means that electrons in nanotubes travel much faster than in metals, and they don't dissipate. This conductivity could be useful in making electric paint, absorbing static, storing energy or replacing chips' silicon circuits.
The best material ever discovered for moving heat from one place to another, nanotubes are potentially handy for cooling confined spaces like PCs.
For their small size, nanotubes are six times lighter than steel but more than 500 times stronger. They could be used to replace copper wires or to create superstrong plastics.
Because they emit light, nanotubes could be used in optical fiber.
Nanotubes can be bent 120 degrees and snap back. Potential failure is therefore reduced.
Strong covalent bonds mean that if an atom goes missing, the remaining carbon atoms will fill the gap.
Unlike silicon circuits, which need to be "drawn," nanotubes form on their own in the presence of a catalyst.
Almost chemically inert, nanotubes won't prompt reactions in other materials. That quality is potentially useful in atomic microscopes or for drug delivery.
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your efforts are appriciated to provide thew usefu... Moazzam Ali Kausar
