Metal-Induced Surface States during Schottky-Barrier Formation on Si, Ge, and GaAs

We report evidence for extrinsic metal-induced surface states during the early stages of Schottky-barrier formation on Si(111), $\mathrm{GaAs}\left(\overline{1}\overline{1}\overline{1}\right)$, Ge(111), and Ge(100). Results on Ge(110) are related to those of Eastman and Freeouf for GaAs(110) and GaSb(110) and we propose a simple structural model to account for the anomalous results on (110) semiconductor surfaces.