Semi-conductors: Diode

Thread Starter


Joined Oct 20, 2010
Hi All,

Maybe my questions are too specific to google, or maybe there's just an error in my logic such that I don't fully comprehend my research because I find the answer to be the same all the time and it still doesn't help.

I get basically what a p/n junction is, what a depletion zone is and how forward bias works. According to my research, reverse bias applies a positive charge to the electron rich side of diode, thus attracting electrons even further from the depletion zone. But if the source of the positive charge provides somewhere for the electrons to go when attracted to the end of the diode, why don't they exit the diode and have all the electrons in the depletion zone start filtering out? Kinda like what happens to the material short on electrons during forward bias.

The only reason I could think of is because the depletion zone breaks the circuit to begin with. Is that really the only reason? If a negative charge is supplied to a spot with holes, electrons can't fill those holes while the electron rich area depletes itself through the drain thus diminishing the depletion zone? What are your thoughts?

Thanks in advance for your contribution. I appreciate it.


Joined Dec 5, 2009
Read about charge separation and breakdown voltages.

Also read up on zener diodes. These are designed to operate in reverse bias. The theory and operation of zener diodes will help answer your question.