Understanding the Depletion Layer in p-n Junction Formation

Click For Summary

Discussion Overview

The discussion revolves around the formation of the depletion layer in p-n junctions, specifically addressing the behavior of ions and charge carriers within the junction. Participants explore the forces at play, including electric fields and diffusion, and the implications for the movement of ions in the semiconductor lattice.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions why negative ions and positive ions in the depletion layer are not influenced by repulsive forces from electrons and holes, suggesting a misunderstanding of the forces involved.
  • Another participant points out that there are both electric fields and diffusion forces acting on charge carriers, which balance out in the space charge region without an external electric field.
  • A third participant emphasizes that the doping ions in the semiconductor lattice do not migrate, as they are part of a crystal structure, and provides links to external resources for further clarification.
  • Some participants express confusion regarding the original question, indicating a need for clearer understanding of the concepts involved.

Areas of Agreement / Disagreement

Participants do not reach a consensus, as there are differing interpretations of the forces acting on the ions and charge carriers in the depletion layer. Some participants provide clarifications while others remain uncertain about the original question.

Contextual Notes

There are limitations in the discussion regarding the assumptions about the behavior of ions and the balance of forces, which are not fully resolved. The complexity of the semiconductor's crystal lattice and the role of doping ions are also noted but not exhaustively explained.

dpacmittal
Messages
2
Reaction score
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?
 
Engineering news on Phys.org
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
 
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 :)
 
Last edited by a moderator:

Similar threads

What Explains the Lack of Current in a PN Junction at Equilibrium?
  • · Replies 3 ·
Replies
3
Views
2K
Electron Current/movement in P-N junction under forward bias
  • · Replies 3 ·
Replies
3
Views
2K
Effect of Doping on Depletion Region Width
  • · Replies 8 ·
Replies
8
Views
17K
What is the polarity of a Pn junction diode
  • · Replies 42 ·
2
Replies
42
Views
10K
Fundamentals of the PN Junction
  • · Replies 12 ·
Replies
12
Views
3K
Depletion zone and current in forward-biased PN junction
  • · Replies 3 ·
Replies
3
Views
3K
Is my understanding of the working principle of a solar cell correct?
  • · Replies 1 ·
Replies
1
Views
1K
Understanding the width of the depletion region in a p-n junction
  • · Replies 6 ·
Replies
6
Views
16K
Undergrad The Role of Doping and Electric Fields in P-N Junction Formation?
  • · Replies 30 ·
2
Replies
30
Views
8K
Non uniformly distributed p-n junction related problem
  • · Replies 3 ·
Replies
3
Views
2K