donor and acceptor level (1 Viewer)

[mreditor16]

Can someone please explain donor and acceptor levels in regard to band theory?

Thanks!

 

[Fade1233]

http://www.halbleiter.org/en/fundamentals/doping/
Hope this helps.
If not then I will explain it:
When a group 3 element, say boron, is added to an intrinsic (pure) semiconductor, silicon, it forms a hole (absence of electron). Now note that the energy required for the electrons to leave the valence band to conduction band in silicon as 1.1 eV. However the dopant, means that there is a hole. And what this hole means that it allows an electron to fill its position. This is possible as per Pauli's Exclusion Principle. Note that the energy required for a electron to go to a hole instead of being moved into conduction band is lower since it is note delocalised completely but rather shared, therefore forming an acceptor level of Boron at fixed energy gap which is a very small ratio of the band gap just above valence band from which it can accept.
The n-type on the other hand has a group 5 element, eg. phosphorus and therefore an extra non-shared electron. Note that this electrons requires minimal energy to go to conduction band as it will readily be delocalised and consumes much less energy than moving delocalising an electron from the silicon shared electron. Hence towards the conduction band with a low energy gap distance since it can readily donate.

 

[anomalousdecay]

http://www.halbleiter.org/en/fundamentals/doping/
Hope this helps.
If not then I will explain it:
When a group 3 element, say boron, is added to an intrinsic (pure) semiconductor, silicon, it forms a hole (absence of electron). Now note that the energy required for the electrons to leave the valence band to conduction band in silicon as 1.1 eV. However the dopant, means that there is a hole. And what this hole means that it allows an electron to fill its position. This is possible as per Pauli's Exclusion Principle. Note that the energy required for a electron to go to a hole instead of being moved into conduction band is lower since it is note delocalised completely but rather shared, therefore forming an acceptor level of Boron at fixed energy gap which is a very small ratio of the band gap just above valence band from which it can accept.
The n-type on the other hand has a group 5 element, eg. phosphorus and therefore an extra non-shared electron. Note that this electrons requires minimal energy to go to conduction band as it will readily be delocalised and consumes much less energy than moving delocalising an electron from the silicon shared electron. Hence towards the conduction band with a low energy gap distance since it can readily donate.

Well this sums it up.

You won't need to know about Pauli's exclusion principle (maybe that's in q2q idk about it though).

Oh and just think of donor level as the point where an electron is ready to be donated to other atoms (so by an n-type) and acceptor level where electrons are accepted (so in a p-type).