N-type and P-type Semiconductors
d) Difference between N-type and P-type semiconductors
In these the impurity of some pentavalent element like P, As, Sb, Bi, etc. is mixed
In these, the impurity of some trivalent element like b, Al, In, Ga etc. is mixed
in these the impurity atom donates one electrons, hence these are known as donor type semiconductors
In these, the impurity atom can accept one electron, hence these are known as acceptor type semiconductors.
In these the electrons are majority current carriers and holes are minority current carriers, (i.e. the electron density is more than hole density nn >> np)
In these the holes are majority current carriers and electrons are minority current carriers i.e. np >> nn
In these there is majority of negative particles (electrons) and hence are known as N-type semiconductors
In these there is majority of positive particles (cotters) and hence are known as P-type semiconductors.
in these the donor energy level is close to the conduction band and far away from valence band.
In these the acceptor energy level is close to the valence band and far away from conduction band.
(e) Conductivity formulae:
(f) Resistivity formulae:
(vii) Characterizes Si and Ge at 300 K
Electron mobility (μn)
Cotter mobility (μp)
Intrinsic current concentration
ni = 2.4 x 1019 cm-3
ni = 1.5 x 1016 cm-3