Homemade semiconductor - Galena crystal detector diode on a curve tracer

[@hamedfarsad]

Homemade diodes has a small breakdown voltage, i made a galena diode with graphite cat whisker with just 2v of breakdown voltage

[@franzliszt3195]

Looks like galena has about half the current for a given voltage of the Schottky diode. I guess that's why we use Schottey's today.

[@MrSlehofer]

that is mainly affected by the surface of the junction, in this case being tiny (contact point of a wire) results in low current capabilities, not to mention other impurities increasing overall resistance

[@franzliszt3195]

@@MrSlehofer Interesting. A galena crystal found in nature I would think would have fewer impurities and having a flat surface might be able to get a bigger contact area. Of course, no one is going to use galena any more due to the Pb in it.

[@MrSlehofer]

@@franzliszt3195 Indeed a natural galena could work a lot better and I should mention that galena is not the only mineral with semiconductive properties, most of metal sulfides (such as galena) and metal oxides (zinc oxide, corundum) can serve as semiconductors.

[@franzliszt3195]

@@MrSlehofer More interesting still. Saw on wikipedia that Gray tin, α-Sn has an eV band gaps about one-7th that of Germanium. I sure its been tried, and failed. I'm getting pretty motivated to make a crystal radio. Thank you -- you got me motivated, which is rather rare.