Photoemission thresholds and linewidths in semiconductors: the contributions of electrostatics

It's often considered that the linewidth, for a core level, or the edge width, for a band, is governed by the lifetime of the hole left upon excitation of the photo emitted electron. In the most cases, the line profiles are actually driven by hardly controlled surface parameters. In the present paper, the particular case of semiconductors is considered: the presence of fixed-point charges, both along the surface and in the bulk, is shown to significantly contribute to linewidths (and edge widths) 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