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Friday October 29 1:53 AM ET
IBM Team Makes Flexible Transistor
By Maggie Fox, Health and Science Correspondent
WASHINGTON (Reuters) - Researchers at International
Business Machines Corp (NYSE:IBM - news). said Thursday
they had created a thin, flexible kind of transistor that could one
day be used to make, for instance, a computer screen that could
be rolled up.
Their invention is cheap and can be sprayed onto plastic, making
it useful in a variety of areas, they said.
``We are really talking about a new class of materials for
transistors,'' Cherie Kagan, a materials scientists at IBM in
Yorktown Heights, New York, who led the study, said in a
telephone interview.
Their new transistors are made out of very thin layers of materials
that can be laid down onto plastic. ``You might be able to
basically build devices on something that is flexible,'' Kagan said.
Transistors currently are made out of materials that have to be
processed at very high temperatures. That means that have to go
onto hard, unmeltable surfaces.
``The display on your laptop is silicon and requires much higher
temperatures,'' Kagan said. ``Plastic couldn't stand up to those
temperatures. You would just obliterate the thing.''
Writing in the journal Science, Kagan and her colleagues describe
their technique, which uses layers of both organic and inorganic
chemicals.
``In this material, you get the benefits of both worlds,'' Kagan
said. ``You get the benefit of an inorganic semiconductor that
(conducts electricity) and an organic material that helps modulate
the structure, and the combination makes them easy to handle out
of solution,'' she added.
``It means that we can take these materials, put them in solution
and spin-coat them. It is a pretty cheap process. The idea is that
it is low-cost and makes it possible to do it at room temperature.''
For their report, Kagan's team used a compound called
phenethylammonium tin iodide. It combines the organic
compound phenethylammonium with the inorganic tin iodide, each
in its own layer, in a coating thinner than a human hair.
Kagan said IBM is looking to see if other metals and organic
compounds will also work.
She said the transistor can basically replace amorphous silicon --
the glasslike version of silicon that is used in computer displays
and elsewhere. It will not replace silicon chips.
``It has device characteristics that are comparable to amorphous
silicon, which is the benchmark,'' she said.
Other scientists are working on materials that could replace the
lighted part of the display.
