Semiconductors + p-n junction doubt

In summary, when electrons from the N region diffuse to the P region, they combine with holes to form a negative ion in the P region, leaving behind a positive ion. This results in a neutral charge for the entire structure. The reason why holes do not have a positive charge on induced doping is because they are just positions in the lattice where no electrons are present. Recombination refers to the process where electrons and holes combine to form a neutral charge.
  • #1
HyDraZin3
3
0
When electrons from N region diffuse to P region, the electrons combine with holes to form a -ve negative ion leaving behind a +ve ion in P region.So, my doubt is how the holes accept the electrons and get a negative charge because as the holes are positively charged, when they accept the electron which is negatively charged the net charge should be neutral.


THANKS
 
Physics news on Phys.org
  • #2
The holes do not have a positive charge, if they are induced by your doping. The holes are just positions in the lattice where no electron is present. As you have a different nucleus with a different charge there, doping gives you holes without any charges.
 
  • #3
can you tell me the reason why holes do not have a positive charge on induced doping?
 
  • #4
HyDraZin3 said:
When electrons from N region diffuse to P region, the electrons combine with holes to form a -ve negative ion leaving behind a +ve ion in P region.So, my doubt is how the holes accept the electrons and get a negative charge because as the holes are positively charged, when they accept the electron which is negatively charged the net charge should be neutral.


THANKS

The net charge of the whole structure (p and n regions) is indeed neutral.
The point is that electrons from the n region combine with holes from the p region (so not from the same region). Before recombination both regions were neutral.
As a consequence of recombination, region n looses some electrons so from neutral becomes positive. Region p gains some electrons (or looses some holes) so it becomes negative. Overall, the n and p regions together have zero charge.
 
  • #5
HyDraZin3 said:
can you tell me the reason why holes do not have a positive charge on induced doping?
Imagine a perfect, neutral lattice of silicon. Now, at a single position, remove one proton from a nucleus and one electron. It is still neutral, as you removed one positive charge and one negative charge. The silicon atom became an aluminium atom, and as you removed one electron there is a position where a new electron from somewhere else can fit in.
You have a hole, but no charge. If an electron moves to this position, you have a filled hole, and a negative charge.
 
  • #6
Thank you all for your help but i have a question:-In wikipedia it is stated that electrons recombines with holes, exactly what does recombination mean, do electrons and holes pair together?
 

Related to Semiconductors + p-n junction doubt

1. What is a semiconductor?

A semiconductor is a material that has electrical conductivity between that of a conductor and an insulator. This means that it can conduct electricity to a certain extent, but not as easily as a conductor. Common examples of semiconductors include silicon, germanium, and gallium arsenide.

2. What is a p-n junction?

A p-n junction is the boundary between two different types of semiconductors - p-type and n-type. In a p-n junction, the p-type material has an excess of positively charged particles (holes), while the n-type material has an excess of negatively charged particles (electrons). This creates a depletion region at the junction, with a built-in electric field.

3. How does a p-n junction work?

A p-n junction works by allowing electric current to flow in one direction, but not the other. When a voltage is applied in the forward direction (from p-type to n-type), the depletion region gets smaller and allows current to flow. In the reverse direction, the depletion region gets larger and prevents current flow.

4. What is the purpose of a p-n junction in electronic devices?

P-n junctions are used in electronic devices as diodes, which allow current to flow in one direction but not the other. They are also used as the basis for transistors, which are essential components in modern electronics. P-n junctions also play a crucial role in solar cells, converting light energy into electrical energy.

5. How are p-n junctions made?

P-n junctions are typically made by doping (adding impurities to) a semiconductor material. Doping with an element that has one more electron than the semiconductor (e.g. phosphorus for silicon) creates an n-type semiconductor, while doping with an element that has one less electron (e.g. boron for silicon) creates a p-type semiconductor. These two materials are then joined together to form a p-n junction.

Similar threads

Replies
2
Views
2K
Replies
30
Views
6K
Replies
3
Views
862
Replies
9
Views
3K
  • Classical Physics
Replies
10
Views
2K
  • Atomic and Condensed Matter
Replies
7
Views
1K
Replies
1
Views
1K
  • Atomic and Condensed Matter
Replies
0
Views
601
  • Introductory Physics Homework Help
Replies
18
Views
2K
  • Special and General Relativity
Replies
9
Views
389
Back
Top