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UIUC Researchers Create Light Emitting Transistor

Posted by timothy on from the I-want-it-to-take-aa-batteries dept.

thesilverbail writes "Researchers at the University of Illinois have demonstrated light emission from the base layer of a Bipolar Transistor. This discovery could be the beginning of an era in which photons are directed around a chip in much the same fashion as electrons have been maneuvered on conventional chips. It's reminiscent of the exciting days of the Miracle month November, 1947, when the transistor was first invented."

7 of 37 comments (clear)

  1. Cool! Lights! by YouHaveSnail · · Score: 1, Interesting

    From Univac to the Connection Machine, computers have always had lights that show what they're doing. I'd love to see a PowerPC or Pentium processor built with this tech and a little window on the chip package so you could look inside and see what the chip is doing! Cheesy, I know, but it'd be a fun and retro nod to our computing heritage. I'm not sure where you'd put the heat sink, though...

  2. End of interchip communincation problem era! by stj · · Score: 2, Interesting

    This is great. It's not to do computations. Really, silicon is good and fast enough for that right now (of course it would be real cool if possible, but that won't work). However, couple this effect with phototransistors which already are in the domain of high frequency (at least theoretical results suggest so - 10 GHz here) and you end of with the dream of board engineers - forget wiring chips with metal. Interconnect them with fiber! Certainly with germanium it's gonna bit a bit difficult, but it's worth it: all you need to wire to chips is power, end of distance limit between chips, and forget problems of spilling something on the board! Even with current germanium version it'll work perfect for connectors between boards.

    --
    iThink iHate iMod
  3. just higher switching speeds by ndevice · · Score: 2, Interesting

    Since switching speed is also a function of the size of the device (capacitance), this transistor probably wouldn't produce any benefit over the LED version.

    The article seems to be saying that they could get higher switching speeds out of this transistor, but we still have inefficiencies here: either the amplified output is used, or the optical output is used. Why would it be necessary to use both? And if the benefits come from not having to drive interconnects between the transistor and LED, we already have integrated transistor/led packages on the same substrate. It might be a better idea to make the emitter current the light emmiting part because then you'd be able to save on component costs.

  4. While this is kind on impressive... by blankinthefill · · Score: 2, Interesting

    I don't think it heralds in any type of light passed processing age. There is still the unresolved problem of creating a sensor that is sesitive to pick up a small amount of light, let alone making such a sensor small amd efficient. Untill that occurs, then this is just another advance that we probably can't use for what we think we can.

  5. Re:This isn't what you think by jralls · · Score: 3, Interesting

    The main reason that FETs are used instead of BJTs in logic devices is that FETs are voltage devices while BJTs are current devices. Logic is much easer to implement with voltage. Amplification, on the other hand, works better with current devices. Hence the BiCMOS processes which are common in the mixed-signal world.

    As for these light-emitting BJTs, unless the light is emitted instead of heat from the resistance losses (which I'd think unlikely), the gain and efficiency of the transistor will be reduced by the light emission.

  6. Nothing to get excited about by JGski · · Score: 3, Interesting
    Since this was done on GaAs/InP, it pretty much assures that the massive adoption date is anywhere from Today+20years to Today+infinity. In case you hadn't heard, GaAs, and III-V in general, has been the "next big thing" in semductors for nearly 30 years now. It's pretty much a niche technology only used when Si absolutely can't do the job at any price because the price to do III-V is usually so high in capital and tech issues that Si, even when price inflated 1-2 orders of magnitude, is *still* overall cheaper.

    Things that would get my attention:

    implemented in SiGe instead of III-V materials

    bidirectional transduction in O->E not just O->E at usable efficiencies

    demonstration of integration into "conventional" manufacturing processes

    Otherwise, it's an interesting academic exercise that might lead to the above points, which is "A Good Thing".

  7. Where this may be useful... by hobit · · Score: 3, Interesting
    The idea that this is somehow enabling optical computing is incorrect as these things can't take light as input. One could use a photodetector of course, but it doesn't seem like a big deal, one could use LEDs to do this today...

    Debugging hardware could become simpler however. You could "see" (or have a computer watch) exactly what each transistor is doing. This could greatly enhance the ability to test real chips. Of course the transistors are usually buried under the metal layers, so I guess it depends on how bright the transistors are or if the designers are willing to leave (lots) of gaps in the metal layer for at least the "important" transistors.

    Mark

    --
    As Nietsche famously said, "If you stare too long into the Abyss, 1d4 Tanar'ri of random type will attack you."