Where is the PN junction of point contact diode?
I think so, the band gap of metal wire drawing; and N type germanium band gap is relatively wide, there are a large number of free electrons near the bottom of the conduction band; when the two contact, N type electronic piece of germanium in the conduction band are more likely to run to the metal conduction band, which is equivalent to the directional movement of free electrons.So the PN junction should be on both sides of the contact surface.
After adding the voltage, the fine aluminum wire melts at the contact point and penetrates into the melted part. In this way, the contact point is actually a p type semiconductor and attaches to the N type semiconductor to form a PN junction.
The manufacturing process is like this: as shown in the picture, one end of the fine aluminum wire is attached to the anode lead, and the other end is pressed on the doped n type semiconductor.
