Semi-conducting materials
1) Semi-conducting are the materials whose valence electrons are bounded somewhat loosely to their atom.
2) They needs energy less than dielectrics and more than good conductors to take away an electron from the parent atom.
3)They have:
(i) An empty conduction band
(ii) Almost filled valence band
(iii) Very narrow energy gap (of about 1eV) separating the two bands.