Evaluation of alkali-induced band-bending inhomogeneity and charge transfer trend from core-level analysis

We present a method for evaluating the spatial inhomogeneity of adsorbate-induced band bending on semiconductors from the substrate core-level lineshape. As a case study we consider the first stages of accumulation layer formation due to K adsorption on the H:Si(lll) surface at 300 K. The observed Si 2p core-level lineshape variation is accounted for considering each randomly distributed adatom as a source,of a screened Coulomb potential. We determine the coverage: dependence of the band-bending distribution, and the parameters characterizing the local K-induced potential.