Fermi Level Position at Semiconductor Surfaces

There have been several recent reports of barrier height studies on metal-semiconductor interfaces. Metals of widely different work functions evaporated onto Si and GaAs surfaces indicated that in each case the energy difference the semiconductor conduction band edge Fermi level at the interface, φ_ (Bn), was essentially of the metal, which indicates the Fermi level is fixed by surface. In the present work barrier height measurements been made on a number of zinc-blende semiconductors to determine (a) if the barriers are in all cases determined by surface states, and (b) the relation between the Fermi at the interface and the band gap Eg.