Re: Silicon LEDs ?

dplatt@[EMAIL PROTECTED]
 (Dave Platt) wrote in news:ngv1s5-k2f.ln1@[EMAIL PROTECTED]
> According to Pease, it occurs because the forward-biased junction is
> acting as an LED, and the junction you're measuring is picking up the
> photons and acting as a photodiode.
> 

I remember reading a long time back that all transistors could be 
phototransistors to some extent, hence light sealing capsules for them
being 
used unless you wanted that to happen. If it is also true that like many 
transducers they work both eays, then few transistors would be incapable
of 
making some light at some wavelength. I don't know if it is a generally 
reversible thing though.

One thing I did find was that an phototransistor and a couple of button
cells 
and a green LED made a great IR sniffer (with part of a dark IR LED's
plastic 
as filter). Given the high gain that allowed me to avoid any other 
components, even unoptimised semiconductors might show light output for 
electrical input if you go looking for it. I've wondered if solar panels
glow 
slightly if you put power into them in reverse, but haven't felt like
trying 
it out on mine...