P and N-type semiconductors (1 Viewer)

[passion89]

I need some more info on them. Could someone clarify the concept of P- and N-type semiconductors?

 

[BigBear_25]

I need some more info on them. Could someone clarify the concept of P- and N-type semiconductors?

• In p-type semiconductors there are more positive holes than negative charge carriers. Elements such as aluminium and gallium (3 valence electrons) are used as doping agents with silicon to produce p-type semiconductors.

• In n-type semiconductors there are more negative charge carriers than positive holes. Elements, such as arsenic and phosphorus (5 valence electrons), are used as doping agents with silicon to produce n-type semiconductors.

This is from: http://www.hsc.csu.edu.au/physics/core/implementation/9_4_3/943net.html#net12

Hope this helps.
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[passion89]

So in other words, p type semiconductors aren't actually positive they're just more positive because there are more holes. And n type semiconductors are more negative because there are less holes?

I think I've got it. Thanks!

 

[helper]

They are not positive at all, there are holes in the lattice, where electrons would normally be. It is these wholes that move.

The semiconductor is still neutral.

 

[del pietro]

i'm a bit confused as to why the semiconductor still remains neutral after it has been doped??

something to do with the metallic holder??

 

[alcalder]

They are still neutral after being doped because they are being doped with atoms that, while they have 5 electrons in the outer valence shell, they also have an extra proton in the nucleus to counterbalance the extra doped electron.


Likewise, when you dope with an atom with only 3 electrons in the outer valence shell, there is one less proton in the nucleus to counterbalance that.

Does that help?

 

[del pietro]

ok thanx for that!