Fermi Level Position at Semiconductor Surfaces

Abstract

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 between the semiconductor conduction band edge and Fermi level at the interface,φ_(Bn), was essentially independent of the metal, which indicates that the Fermi level is fixed by surface states. In the present work barrier height measurements have 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 energy at the interface and the band gap E_g.