What Is The Definition Of Energy Band Theory?
According to the energy band theory, the energy levels split into many closely-spaced levels which they define a band. There are various bands, but most are completely filled or empty. The two at the boundary between filled and empty, determine behaviors of insulators, metals and semiconductors. At zero temperature, the levels are filled by electrons up to Fermi energy, above which all levels are vacant. If the Fermi level is at the top of a band, the material is an insulator and filled bands are called valence bands. If that level is above the bottom of a band, it narrates a “conduction band” which is populated by electrons which are free to move.
