Understanding the Depletion Layer in p-n Junction Formation

AI Thread Summary
In p-n junction formation, electrons from the n-type material combine with holes in the p-type, creating negative ions in the p-type and leaving positive ions in the n-type. The discussion highlights that these ions are not attracted to each other due to the presence of both an electric field and a diffusion force that balance in the space charge region. The ions do not migrate through the semiconductor's crystal lattice, which is made of silicon or germanium with impurities. This balance prevents the uniform distribution of ions across the junction. Understanding these forces is crucial for grasping the behavior of charge carriers in semiconductors.
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In p-n junction formation,
Electron from n-type combine with holes on p-type to form negative ions leaving behind positive ions on n-type.

Now, why aren't these negative ions and positive ions attracted by electron on n-type and holes on p-type respectively?

They restrict further movement of electrons or holes but why these ions themselves aren't moved with repulsive forces?

Both the above factors would've uniformly distributes the negative ions on positive side and positive ions on negative side. But this doesn't happens... why?
 
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I don't fully understand your question but I think you're confused because you don't realize there is both an electric field and a diffusion force on the charge carriers, and in the space charge region, with no external electric field, they balance.

This page is very good and has more details (and lot's of great images).
See Figure A in particular.
http://en.wikipedia.org/wiki/P-n_junction
 
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es1 said:
I don't fully understand your question but I think you're confused because you don't realize there is both an electric field and a diffusion force on the charge carriers, and in the space charge region, with no external electric field, they balance.

This page is very good and has more details (and lot's of great images).
See Figure A in particular.
http://en.wikipedia.org/wiki/P-n_junction
Thanks :)



dlgoff said:
Remember that the semiconductor is a crystal lattice of silicon or germanium with an impurity that is http://hyperphysics.phy-astr.gsu.edu/hbase/solids/dope.html#c1", so these doping ions don't actually migrate through the crystal.

Take a look at this explanation of http://hyperphysics.phy-astr.gsu.edu/hbase/solids/pnjun.html#c2".

Welcome to PF

Yes, this was what I was looking for. Thanks :)
 
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