INVERSE PHOTOEMISSION AT SEMICONDUCTOR SURFACES.

Abstract

Inverse photoemission is used as a novel probe for unoccupied electronic states. We observe unoccupied surface states on silicon and study their dependence on crystallographic orientation. Critical points of the conduction bands of bulk silicon are determined, e. g. , L//1**C at 2. 30 ev and L//3**C at 4. 15 ev above the valence band maximum. New high-resolution data from cleaved GaP(110) surfaces show a surface state located at 0. 3 ev below the conduction band minimum. For Pd//2Si the density of unoccupied antibonding states is determined.