11. The intrinsic Fermi level does not change. 12. This pins the Fermi level in the semiconductor to a position in the bulk gap. 13. In nominally doped semiconductors, the Fermi level lies between the conduction and valence bands. 14. The two quasi-Fermi levels do not coincide except deep in the bulk materials. 15. When the Fermi level of graphene is tuned, its optical absorption can be changed. 16. The characteristic energy level up to which the electrons have filled is called the Fermi level . 17. The Fermi level of an intrinsic semiconductor is exactly in the middle of the band gap. 18. The isosurface of states with energy equal to the Fermi level is known as the Fermi surface. 19. When a material's Fermi level falls in a bandgap, there is no Fermi surface. 20. A more convenient definition of'voltage'can be found instead in the concept of Fermi level .
