Valence
band energies are low as compared to conduction band energies All
energy levels in the valence band are filled while energy levels in the
conduction band may be fully empty or partially filled The electrons in
the conduction band are free to move in a solid and are responsible for
the conductivity The extent of conductivity depends upon the energy
gap (Eg) between the top of valence band (EV ) and the bottom of the
conduction band EC