an n type semiconductor has majority charge carriers as the electrons then why is it said to be neutral and not negatively charged?

Asked by ABHINAV SHARMA | 19th Nov, 2012, 12:33: PM

Expert Answer:

If we see the lattice structure of n type semiconductors we can see that the original silicon atoms and also the doped ie , impurity atoms(pentavalent atoms)both are neutral.not ionised. but when impurity is added to the original semiconductor, then 4 out of the 5 valence electrons of the impurity atom get bonded with the 4 valence eletrons of the semiconductor.So one of the 5 outer most valence electrons of the impurity atom remains unpaired,ie, free to move. So in these n type semiconductors a number of such unpaired electrons are available for conduction.
We talk about these free electrons as majority charge carriers.

Answered by  | 19th Nov, 2012, 02:36: PM

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