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Room-temperature transistor laser is step closer to commercialization
James E.
Kloeppel, Physical Sciences Editor
217-244-1073; kloeppel@illinois.edu
9/26/2005
|
CHAMPAIGN, Ill.
— Researchers at the University of Illinois at Urbana-Champaign
have demonstrated the room-temperature operation of a heterojunction
bipolar transistor laser, moving it an important step closer to commercialization.
The scientists describe their work in the Sept. 26 issue of the journal
Applied Physics Letters.
“We have shown that the transistor laser, even in its early state
of development, is capable of room-temperature operation at a speed
of 3 gigahertz,” said Nick Holonyak Jr., a John Bardeen Chair
Professor of Electrical and Computer
Engineering and Physics at Illinois. “We expect the device will operate at much higher
speeds when it is more fully developed, as well as play an important
role in electronic-photonic integrated circuits.”
Room-temperature transistor lasers “could facilitate faster signal
processing, large capacity seamless communications, and higher performance
electrical and optical integrated circuits,” said Milton Feng,
the Holonyak Chair Professor of Electrical and Computer Engineering
at Illinois. Feng’s research on heterojunction bipolar transistors
has produced the world’s fastest bipolar transistor, a device
that operates at a frequency of 600 gigahertz or more, and is a natural
platform on which to develop a transistor laser.
The Illinois researchers first reported the demonstration of a light-emitting
transistor in the Jan. 5, 2004, issue of Applied Physics Letters. They
described the first laser operation of the light-emitting transistor
in the Nov. 15, 2004, issue of the same journal. At that time, the transistor
laser had to be chilled with liquid nitrogen to minus 73 degrees Celsius.
Room-temperature operation is ultimately required for large-scale commercial
applications, said Holonyak, who also is a professor in the university’s Center for Advanced Study, one
of the highest forms of campus recognition. “If this device operated
only at low temperature, nobody would want it, except as a laboratory
curiosity or for very limited applications.”
After the demonstration of the first semiconductor laser (as well as
the first practical light-emitting diode) in 1962, “it took the
effort of many people eight years to get the diode laser to operate
at room temperature,” Holonyak said. “Then it took an additional
two years to make it reliable. But the big payoff has only now just
begun, after more than 40 years of additional work.”
In comparison, it has taken the Illinois researchers less than a year
to move the transistor laser from cold operation to room-temperature
operation. “Who knows where this new transistor laser technology
will be in another 40 years,” Holonyak said. “The payoff
part of scientific and technological advances never occurs rapidly,
at least not the ‘big payoff.’
“The transistor laser is still a primitive, laboratory device
that will require a lot more work,” Holonyak said. “Eventually,
optimizing the design and fabrication will result in higher speed laser
operation and improved performance, as well as a naturally advantageous
way to realize electronic-photonic integrated circuits.”
Co-authors of the paper with Feng and Holonyak are postdoctoral research
associates Gabriel Walter and Richard Chan. The Defense Advanced Research
Projects Agency funded the work.
Editor’s note: To reach Nick Holonyak, call 217-333-4149
To reach Milton Feng, call 217-333-8080; e-mail: mfeng@illinois.edu.
