A development that just might revolutionize the computer chip scene was announced this week by two engineering professors at the University of Illinois at Urbana-Champaign.
 
    It's the creation of a superfast transistor that produces both electronic and optical signals. Such an optical/electronic device could radically boost the amount of work individual computer chips can do.
 
    After looking into securing patent rights for the university, the two professors--Nick Holonyak Jr. and Milton Feng--published their work in Applied Physics Letters. The two are well-known in transistor circles.
 
    Feng has been burning up the solid-state world by building transistors that set speed records, and Holonyak invented the light-emitting diode.
 
    Their joint work in producing transistors that emit both electronic and photonic signals grew out of their habit of discussing their work over coffee in Holonyak's office.
 
    Intrigued at Feng's ability to coax ever greater speed from tiny transistors, Holonyak questioned him about the nature of the current running through his devices. Eventually, Holonyak concluded that since Feng's transistors weren't cooking themselves in their own heat, some energy must be given off as light.
 
    "I said there's got to be light given off or the transistor couldn't work," Holonyak recalls. "It's not something people would look for, but we're good at looking for it."
 
    After several months of looking, they found the light and learned that it is emitted at unprecedented high speed set by the transistor's operation. The light signal can be controlled by modifying the electronic signal.

    "A typical transistor has an electrical input and an electrical output," said Feng. "These have electrical input, but they have two outputs: one electronic and one optical."
 
    While the commercial potential of their discovery is huge, neither scientist expects to see products based on their work soon. It could take five or ten years, Feng said.
 
    It was 40 years ago when Holonyak first demonstrated that electrons could reliably produce photons in a solid-state device, and many commercial products, from traffic lights to flashlights, use light-emitting diodes today. But the true potential of LEDs is only starting to blossom, he said.
 
    "Eventually, LEDs will replace most incandescent light bulbs," Holonyak predicted.
 
    Just what will come of the optical/electronic transistor he and Feng discovered is difficult to say right now because much more work lies ahead, but Holonyak said, "I think it's fairly important. There's a good possibility this is something with a big future."
 
    Holonyak's mentor, the late John Bardeen, a co-inventor of the transistor more than 50 years ago, "would have to have a big grin" if he could see the device that may take transistors to a higher level of usefulness, Holonyak said.