CANADA -- A scientist at the U.S. Department of Energy's
Brookhaven National Laboratory, working with colleagues
at the IBM
T.J. Watson Research Center, has caused an individual
to emit light for the first time. This step in research
on carbon nanotubes may help to materialize many of
the proposed applications for carbon nanotubes, such
as in electronics and photonics development.
light emission is the result of a process called "electron-hole
recombination." By running an electric current
through a carbon nanotube -- a long, hollow cylindrical
molecule that is only one and a half nanometers (a
billionth of a meter) in diameter -- negatively charged
electrons in the nanotube molecule combine with positively
charged "holes," which are locations in
the molecule where electrons are missing. When an
electron fills a hole, it emits a photon -- a tiny
burst of light.
produced infrared light by applying voltages to a
specific type of nanotube such that many electrons
and holes end up in the nanotube, where they combine.
This makes the nanotube the world's smallest electrically-controllable
light emitter," said James Misewich, a materials
scientist at Brookhaven. "It's an exciting result,
and my colleagues and I plan to continue studying
to determine the mechanisms behind it. For example,
we hope to understand how to make the nanotubes emit
other types of light, such as visible light, and how
to increase the efficiency of the emission."
nanotubes do not yet have any mainstream practical
applications, but researchers are investigating ways
to use them in flat-panel displays, such as televisions
and computer monitors, or as reinforcements in building
materials, due to their exceptional mechanical strength.
Misewich also suggested that, if additional research
leads to an increased efficiency of nanotube light
the nanotubes could possibly be used in lighting applications.
of the ten national laboratories overseen and primarily
funded by the Office of Science of the U.S. Department
of Energy (DOE), Brookhaven National Laboratory conducts
research in the physical, biomedical, and environmental
sciences, as well as in energy technologies and national
security. Brookhaven Lab also builds and operates
major scientific facilities available to university,
industry and government researchers. Brookhaven is
operated and managed for DOE's Office of Science by
Brookhaven Science Associates, a limited-liability
company founded by Stony Brook University, the largest
academic user of Laboratory facilities, and Battelle,
a nonprofit, applied science and technology organization.
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