I need a Germanium Zener diode for a shot noise generator circuit. If I am correct, Silicon replaced Germanium for use in diodes and other semiconductors because of the fact that Germanium diodes have a much higher reverse leakage and are much noisier. But due to the smaller band gap of Germanium as compared to Silicon, this makes them more useful in shot noise generators since at the Zener voltage, a Germanium Zener diode has a depletion region that is smaller than the electron wavelength and as electrons tunnel through it, their energy levels spread out due to the uncertainty principle.

  • \$\begingroup\$ Also, well actually, from what I've read(and correct me if I'm wrong about this!)is that Germanium is somewhat more metallic than Silicon even they're both metalloids because the conduction and valence bands of Germanium actually overlap(but the overlap region is much smaller than with most metals)whereas with silicon there isn't normally an overlap but a very small band gap. \$\endgroup\$
    – Mr X
    Apr 9 '15 at 3:34
  • \$\begingroup\$ They're still around in small quantities, e.g. e-bay, but I wouldn't base an industrial product on them. \$\endgroup\$
    – user207421
    Apr 9 '15 at 3:39
  • \$\begingroup\$ EJP, can you give me some makes and model numbers of Zener diodes that are actually made of Germanium? \$\endgroup\$
    – Mr X
    Apr 9 '15 at 3:47
  • \$\begingroup\$ 1N34A appears to still be available from several different suppliers. That's after a 15-second Google search, which you perhaps should do. \$\endgroup\$ Apr 9 '15 at 4:13
  • 2
    \$\begingroup\$ @DwayneReid: the 1N34A is a signal diode, not a Zener. \$\endgroup\$ Apr 9 '15 at 4:22

oa126 is a germanium zener diode.


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