Understanding the Depletion Layer in p-n Junction Formation

In summary, during p-n junction formation, electrons from the n-type material combine with holes on the p-type material, leaving behind negative ions on the n-type side and positive ions on the p-type side. These ions restrict further movement of electrons and holes due to a balance of electric field and diffusion force. This prevents the ions from being uniformly distributed on opposite sides. This is due to the fact that the impurities in the semiconductor do not allow the ions to migrate through the crystal. For more information and visuals, refer to the provided links.
  • #1
dpacmittal
2
0
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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  • #2
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
 
  • #3
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  • #4
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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1. What is a depletion layer?

A depletion layer, also known as a depletion region, is a region in a semiconductor material where the concentration of free charge carriers (electrons or holes) is greatly reduced due to the presence of an electric field.

2. How is a depletion layer created?

A depletion layer is created when a p-n junction is formed between two different types of semiconductors (p-type and n-type) by doping impurities into the material. The resulting difference in charge carriers creates an electric field that causes the depletion of charge carriers in the region between the two materials.

3. What is depletion layer confusion?

Depletion layer confusion refers to the misunderstanding or misconception about the functioning and behavior of depletion layers in semiconductors. This can occur due to the complex nature of semiconductor devices and the confusion between depletion layers and other types of layers, such as diffusion layers or depletion zones.

4. How does a depletion layer affect the behavior of a semiconductor device?

The presence of a depletion layer can significantly impact the performance of a semiconductor device. It can act as a barrier to the flow of current, control the direction of current flow, and affect the capacitance of the device. It also plays a crucial role in the functioning of diodes, transistors, and other semiconductor devices.

5. Can a depletion layer be intentionally manipulated?

Yes, a depletion layer can be intentionally manipulated by applying an external electric field or by changing the doping levels in the semiconductor material. This is often done in semiconductor device fabrication to control the behavior and performance of the device.

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