| 1. Valence band or conduction band are partially filled.||Valence Band is completely filled with electrons and conduction band is empty.||At 0K, electrons in valence band do not have sufficient energy to jump to conduction band.|
|2. Valence and conduction bands overlap.|
Energy gap ~ 0 eV.
|Valence and conduction band have Energy gap ~ 6 eV.|| Forbidden gap in between conductors and insulators. Energy gap ~ 3 eV.|
|3. Conductivity is highest.||Conductivity is very low.||Conductivity is in between conductors and insulators.|