An extrinsic semiconductor which has been doped with electron donor atoms is called an n-type semiconductor, because the majority of charge carriers in the crystal are negative electrons.

Why is n-type semiconductor electrically neutral?

An n-type material by itself has mainly negative charge carriers (electrons) which are able to move freely, but it is still neutral because the fixed donor atoms, having donated electrons, are positive.

Why do we prefer N-type semiconductors?

Since the minority carriers are electrons and holes in p-type and n-type semiconductors, respectively, the order of increase in electron density in p-type semiconductor and hole density in n-type one are more sensible than increase in hole density in p-type semiconductor and electron density in n-type one, respectively ...