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Forum: Analog Circuits LED from Silicon Carbide

Author: Leuchti (Guest)
Posted on:

Hello,

I replicated the experiments of H.J. Round and Oleg Losev, the inventors
of the LED and build an LED from a mineral substance myself. If you
like, have a look on it, you might also want to try it ;-)

http://www.dlip.de/?p=99

Cheers!
Michael
Author: Andreas Schwarz (andreas) (Admin) Flattr this
Posted on:

Nice idea! I have a big chunk of this stuff lying around (although I
could never figure out what it was, now I know) and I'm definitely going
to try the LED.
Author: Eddy Current (chrisi)
Posted on:

Shouldn't the rear side of an old (maybe destroyed) processor work for
such an experiment? I think about those CPUs, where the chip is mounted
in flip chip technology without heat spreader. CPU goes LED :-)
Author: Jörg Wunsch (dl8dtl) (Moderator)
Posted on:

I don't think plain Silicon emits visible light.
Author: Leuchti (Guest)
Posted on:

No, doesnt work! It needs a semiconducting material with
electroluminescent properties. Like SiC or SnO. What I really wonder is
whether SiC grains from sand paper can be made working. That would allow
a much greater audience to replicate the experiment. Is it plain SiC or
coated somehow?
Author: Leuchti (Guest)
Posted on:

Unbelievable! The article made it to hackaday.com!
http://hackaday.com/2009/05/07/make-your-own-leds/
Author: faustian (Guest)
Posted on:

Author: Leuchti (Guest)
Posted on:

oh, nice idea! It seems he smoked the setup pretty badly but it worked.
A little more power and he would have had a incandescent lamp...
Author: Andreas Schwarz (andreas) (Admin) Flattr this
Posted on:
Attached files:
  • preview image for 2.jpg
    2.jpg
    2 MB, 664 downloads

I tried it, but I can't say I had a lot of success.

A picture of my material is attached. It is from a ceramics factory that
works with SiC, and it looks like the SiC picture I found on Wikipedia,
so it probably is SiC. Can anyone confirm?

The conductivity of the nice, big crystals on top is very low, I could
only measure a finite resistance at the lower part of the material. When
I connected my power supply and traced the material with the needle (a
few mm from the connection) I had to crank the voltage to 30 V to get to
10 mA. I do see a tiny light occasionally, but I also see some faint
smoke, so what I'm seeing is probably the contact point overheating. I
will give it another try tomorrow.
Author: Knut Ballhause (Company: TravelRec.) (travelrec)
Posted on:

For me it looks like more or less "pure" silicon. Not SiC.
Author: Jens G. (jensig)
Posted on:

pure silicon is grey, not black. Pure SiC normally is colorless, but
normally black because of impurities (technical SiC). I think, these
impurities (if not to much) causes the lighting like a LED.
Author: Leuchti (Guest)
Posted on:

It depends on the material surface properties. As I wrote, I have a few
boxes of the stuff and not all crystals work well. The LED effect can
easily be distinguished from overheating by the green light. Overheating
is orange and the LED orange or green. If it is green it's certainly not
overheating. For your material I'd guess that it is not pure enough...
Author: Leuchti (Guest)
Posted on:

Hi again, I just tried a bigger chunk just like yours. The molten
surfaces seem to be ideal. They give much brighter light then the
crystal surfaces. And what can make like almost every crytal work: use
30 V, limit the current to 30 mA and attack the negative lead to a fine
tip pencil (Feinminenbleistift). When tracing the crystal with that
sucess rate is much greater, although there might be a lot of sparks
having nothing to do with the LED effect. But typically for the LED
effect a larger region lights up green or orange. Like a little crack or
so in the crystal. These regions are reproducible and always give the
same light in the same place and with the same shape.

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