Illinois researchers invent light-emitting transistor

Researchers fabricated the light-emitting transistor in the university's Micro and Nanotechnology Laboratory. Light-emitting transistors are made from indium gallium phosphide and gallium arsenide.

"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," Holonyak reported.

"This work is still in the early stage, so it is not yet possible to say what all the applications will be," Holonyak said. "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."

The recombination process in indium gallium phosphide and gallium arsenide materials also creates infrared photons. "In the past, this base current has been regarded as a waste current that generates unwanted heat," Holonyak said. "We've shown that for a certain type of transistor, the base current creates light that can be modulated at transistor speed."