Professors Holonyak & Feng Shed Light on Next Gen Transistors

The News Bureau at the USA’s University of Illinois Urbana-Champaign has posted
an exciting and well written story
covering Nick Holonyak Jr.’s and Milton Feng’s newly published research on what
appears to be a “light emitting” HBT. The new genre optoelectronic
device was grown by MOCVD, layering InGaP, InGaAs, and GaAs on a GaAs substrate.
As those in the compound semi research community well know, Nick is regarded
as the true “inventor” of the LED and Milton is noted for his record-breaking
transistors. Both are undisputed compound semi industry epitaxy experts. The
full story on the
U of Ill site is titled New Light Emitting Transistor Could Revolutionize
Electronics Industry
and is authored by Physical Sciences Editor, James
E. Kloeppel. In it, Nick was quoted as saying, “We have demonstrated light
emission from the base layer of a heterojunction bipolar transistor, and showed
that the light intensity can be controlled by varying the base current. This
work is still in the early stage, so it is not yet possible to say what all
the applications will be. But a light-emitting transistor opens up a rich domain
of integrated circuitry and high-speed signal processing that involves both
electrical signals and optical signals.
” In outlining how their new
device works, Milton explained that, whereas a transistor usually has two ports
(one for input, one for output), “Our new device has three ports: an
input, an electrical output and an optical output. This means that we can interconnect
optical and electrical signals for display or communication purposes
.”
Giving credit where credit is due, it was their graduate student, Walid Hafez,
who fabricated the new light-emitting transistor in the university’s Micro and
Nanotechnology Laboratory. The team has demonstrated the modulation of light
emission in phase with a base current in transistors operating at a frequency
of 1 megahertz, and reported that much higher speeds are considered certain.
In regard to the application potential, Milton Feng surmised that, “At such
(higher) speeds, optical interconnects could replace electrical wiring between
electronic components on a circuit board.”
The researchers pointed
out that their work was rooted the original Nobel prize-winning work on Ge transistors
by John Bardeen and Walter Brattain. Nick Holonyak was Bardeen’s first grad
student. Nick cleverly closed the news bureau coverage pointing out that his
mentor couldn’t see what they now see in GaAs. “The direct recombination
involving a photon is weak in germanium materials, and John and Walter just
wouldn’t have seen the light – even if they had looked. If John were alive and
we showed him this device, he would have to have a big grin
.”