 If the electron affinity "E"EA and the surface's band-referenced Fermi level "E"F-"E"C are known, then the work function is given by
where "E"C is taken at the surface.From this one might expect that by doping the bulk of the semiconductor, the work function can be tuned.In reality, however, the energies of the bands near the surface are often pinned to the Fermi level, due to the influence of surface states.