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- NEW YORK - Researchers
have developed a chemical process that could lead to computer components
no thicker than a single molecule, an important step toward the creation
of ultrafast machines.
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- A team from Hewlett-Packard Co. and the University of
California at Los Angeles says its work could ultimately lead to computers
100 billion times faster than today's most powerful personal computers.
Their findings were published Friday in Science magazine.
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- Until now, integrated circuits - the on-off switches
that are the basis for computing - have been made by etching silicon wafers
with beams of light. The ability to shrink those circuits is limited by
the wavelength of light.
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- But the researchers said they found a way to construct
the circuits using a chemical process, making the switches as small as
a molecule. They believe the process could lead to components much smaller
than today's smallest transistors.
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- Smaller transistors consume less power and generally
switch on and off more quickly. They also can be produced in greater quantities
without raising production costs.
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- The team at UCLA and at Hewlett-Packard created a molecular
"logic gate," which forms the basis of how a computer works.
"We have actually built the very simplest gates used in computers
- logic gates - and they work," Phil Kuekes, a computer architect
at Hewlett-Packard in Palo Alto, said in a telephone interview.
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- Logic gates switch between "on" and "off"
positions, creating the changes in electrical voltage that represent "bits"
of information.
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- James Heath, a UCLA chemistry professor who worked on
the project, said his team did this by creating a new compound, called
rotaxane, which grows in a crystalline structure. Writing in Science, Heath's
and Kuekes' teams said the rotaxane molecules, sandwiched between metal
electrodes, functioned as logic gates.
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- Computers are now based on silicon chips. The information
they carry is etched onto them, and it is becoming harder and harder to
do this precisely on ever-smaller chips.
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- But a crystal can absorb information, in the form of
an electrical charge, and organize it more efficiently.
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- The "chips" made using this molecular technology
could be as small as a grain of dust, Kuekes said. "When you walk
into a room, it will turn the TV to your favorite channel. Or instead of
getting carpal tunnel syndrome pushing a mouse around, your finger becomes
the mouse," he said.
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- The next step will be structuring the chip. Instead of
etching this structure onto the surface, as is done now with silicon chips,
it will be downloaded electrically.
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- "We can download all the complexity, by wire, attached
to a bigger computer," Kuekes said.
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- But currently available wires are too big - much bigger
than the rotaxane molecules - to do this. "So the next step is going
to be to shrink the wires until they are the same diameter as the molecules,
and then we will have the miniaturized technology," he said.
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- It might be possible to use carbon nanotubes - long thin
tubes made of pure carbon. Also known as "Bucky tubes," they
are no thicker than most molecules.
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- The researchers said their findings are only a first
step. For example, the current device can switch only from one state to
another and cannot switch repeatedly, which it must do if it is to replace
silicon-based chips.
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