Zener Diode Breakdown: Effects on PN Junction & Holes/Electrons

[Dr. Manoj]

Once the zener Diode is formed by breakdown of pn junction Diode, potential across Diode remains constant. If we again change the configurations from reverse bias to forward bias, is it possible to get back the normal pn junction as before the breakdown and will potential across junction be adjustable again as before? If no, why and what all happens after breakdown to holes and electrons? Please explain

 

[Svein]

This characteristic diagram of the current vs. voltage of a Zener diode should answer your questions.

 

[DarkBabylon]

I think the answer is within the name for it. The Zener breakdown.
In a breakdown of a diode the depletion layer can no longer resist the electrons and holes wanting to move due to the potential difference. A diode that has a reverse bias of 5 volts and still doesn't give in, it is basically a capacitor (with a leak). What happens to a capacitor when it can't resist the charges will to move? It would allow the current to flow, as it breaks down, the diode as well.
The difference between a Zener diode and a regular diode is that it is built to handle high currents (typically mA) in reverse bias, whereas a regular diode would make a puff and not work anymore.