Schematics of calculated band structure of crystalline Si (NOT TO SCALE) Reference: 

Chelikowsky, J.R. &amp; Cohen, M.L.: Electronic structure of silicon. Physical Review B 10, 5095-5107(1974).
Chelikowsky, J.: Silicon in all its forms. MRS Bulletin(USA) 27, 951-960(2002).
Si-band-schematics.PNG
derivative work: Cepheiden (talk)
Si-band-schematics.PNG: S-kei