Semiconductors- interesting questions (1 Viewer)

[corpse]

So, we all know that n-type and p-type semiconductors are different because of the way current flows through them; either by positive holes, or negative electrons.

n-type semiconductors are doped with elements from Group V (5) of the periodic table, and these atoms replace some of the atoms in the semiconduter. These atoms have an extra electron, which is free to move, making the electrons in the doped semiconductor the main carriers of electricity.

p-type semiconductors are doped with elements from Group III (3) of the periodic table, and these replace some of the atoms from doped semiconductor with atoms with LESS electrons; there are now positive holes in the covalent bonds, which are the main carriers of electricity.



Are there any differences between these two types of semiconductors?

They both effectively increase the conducting properties of a semiconductor, but is there any reason you would use an n-type over a p-type? Or the other way around?

Or is it just to increase the amount of different materials avaliable, for a wider variety?

Is it strictly only elements from groups 3 and 5 that can be used for doping?


Not exactly part of the syllabus, but I'm interested...

 

[helper]

The selection is normally based on the use of them to make a junction and the resultant bias you want to apply to it.

Think of your answerr to how solar cells work.

 

[azn-drew]

between the two types of doping I don't think there is a difference, after all they both cause extrinsic conduction. within each type though, different elements are used for different properties such as control.
not very useful info though. =]

 

[corpse]

Thanks

Should probably be getting on with more important stuff anyway...

good luck anyone/everyone for Tuesday!

 

[independantz]

N-type> P-type in terms of conduction

N-type semiconductors use a flow of electrons as a primary means of conduction whilst P-type use the holes, as conduction is generally a flow of charge.

Other than that the main difference is the impurity used to dope the semiconductor.