In n-type semiconductor the impurities are added to the intrinsic
semiconductor in small traces.To the semiconductor the pentavalent
elements such as phosphorous(p),arsenic(As) or antimony(sb) have five
electrons in their outer most shells, so these are added to
semiconductor as the impurities. And from this pentavalent element the
four electrons are engaged in covalent bonding to parent atom. Since
these pentavalent elements donate negative charges(electrons) to the
semiconductor they are called as N-type impurities and the
semiconductors doped with pentavalent impurities are called N-type
semiconductors. If
there is high thermal energy and sufficient doped impurity atoms,then
there occurs the breakage of covalent bonds, by this they generate
electron-hole pairs. In N-type semiconductors electrons are majority
carriers and holes are minority carriers. 04:53
