PHOTOEMISSION THRESHOLDS AND LINEWIDTHS IN SEMICONDUCTORS - THE CONTRIBUTIONS OF ELECTROSTATICS

It is often considered that the linewidth, for a core level, or the ed gewidth, for a band, is governed by the lifetime of the hole left upon excitation of the photoemitted electron. In most cases, the line prof iles are actually driven by hardly controlled surface parameters. In t he present paper, the particular case of semiconductors is considered: the presence of fixed-point charges, both along the surface and in th e bulk, is shown to significantly contribute to linewidths (and edgewi dths) in the photoemission process. A numerical treatment is presented in the specific case of n-type silicon. The effect of surface dipoles on photoemission peak profiles is discussed.