Big future for very small machines
(Reuters; 11/09/98)
By Niall McKay SAN FRANCISCO (Wired) - Imagine a tiny machine
travelling along inside the capillaries of your hand, entering and
repairing damaged cells as it rides along on a current of blood. It's not
happening yet. But more than 300 scientists will discuss this and other
future applications for nanotechnology at the Foresight Conference on
Molecular Nanotechnology, this week in Santa Clara, Calif. "If Moore's law
is correct, microprocessors will reach the atomic level by about 2015,"
said Christine Peterson, director of the Foresight Institute and co-author
of Unbounding the Future: the Nanotechnology Revolution. For the past six
years, the Foresight Conference has been at the center of the effort to
transform molecular nanotechnology, still largely a science fiction
fantasy, into scientific reality. Companies such IBM, Lucent, and Sun will
join scientists from NASA and academics from Stanford University and MIT to
discuss how to fabricate equipment one-thousandth of the diameter of a
human hair. This year, nanotech startup Zyvex and Washington University
will demonstrate one of the basic building blocks for a molecular
assembler: a nanomanipulator, which can manipulate atoms or very small
particles. Zyvex is using the technique to suspend tiny materials, known as
carbon nanotubes-sheets of hexagonal carbon atoms wrapped into a
cylinder-and attempting to measure their properties and manipulate them. In
the past, researchers have been able to pick up atoms with an atomic force
microscope, but it has been impossible to lift or move them with any
precision.
"Until now, all we have been able to do is to examine carbon nanotubes on a
flat surface," said Rod Ruoff, director of the Laboratory for the Study of
Novel Carbon Materials at Washington University. Nanotechnology may enable
scientists to develop machines small enough to be injected into the human
blood stream and sent to attack cancerous growth, a scenario straight out
of the 1966 science fiction movie Fantastic Voyage. "Nature is already good
a creating these tiny structures," said Ralph Merkle, a research scientist
at Xerox's Palo Alto Research Center, in Palo Alto, California. Scientists,
too, are "slowly getting to a stage where we can place atoms with some
precision." The short term practical applications for nanotechnology, while
somewhat less dramatic, could be more lucrative. For example,
microprocessor manufacturers could one day use nanotechnology to etch
silicon or make tiny resistors and capacitors.
---Already, IBM and Sun are beginning to investigate the use of carbon nanotubes in silicon-based microprocessors. "With carbon nanotubes, the flow of electricity can be ballistic, meaning that it can flow without collision," says Phaedon Avouris, a research scientist at IBM's Thomas J. Watson Research Center, in Yorktown Heights, New York. "We believe that they can be used as field-effect transistors or on/off switches in computing devices." The concept of molecular nanotechnology was first raised by Richard Feynman in a 1959 paper, There's Plenty of Room at the Bottom. The concept was expanded in 1992 by scientist K. Eric Drexler in his book Nanosystems. "I don't have any illusions about what we are trying to achieve here," said Von Ehr, founder and CEO of Zyvex, based in Richardson, Texas. He estimates it will take 10 years for Zyvex to build a molecular nanotechnology assembler. So far, it is the only commercial venture with the people and financing to make it happen. "We are just learning to do the science that is required to lay the foundation for an assembler," said Von Ehr. For about a year, Zyvex researchers have used conventional scanning probe microscopes in conjunction with computer aided design (CAD) software. Together they provide a computer-generated representation of the atoms as they are being moved by the atomic force microscope. Von Ehr said it has been difficult to place atoms with any precision because of a scientific principle known as the Van der Waalf force, which describes the force atoms feel for one another. In the case of carbon nanotubes, the Van der Waalf force explains why the atoms stick to the tip of a scanning probe microscope. "When we first discovered this it was spoiling our experiment, but you have to use physics they way that physics wants to be used," said Von Ehr. "We then discovered that we could use it to move and manipulate the atoms." Von Ehr is pleased with the discovery, but it is only the beginning. There are three major hurdles that need to be overcome, Von Ehr said. First, Zyvex needs to develop the chemistry that will bond atoms together; second, it needs to develop a tool that will position atoms to within a tenth of a nanometer; finally, Zyvex needs to combine both capabilities in a single piece of equipment. "Zyvex is one of the few companies that is really aware of what is involved," said Paterson, of the Foresight Institute. "But with science, you never know who is going to have one of those happy accidents that leads to a breakthrough." (Reuters/Wired)
{Reuters:Wired-1109.00364} 11/09/98
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