High-resolution Si 2p core-level photoemission spectroscopy on Sb-terminated Si(100) surfaces: evidence for a strong interfacial component

Abstract

High-resolution core level spectroscopy using a third-generation synchrotron light source has been used to characterize the Sb-terminated Si(100) surface. On the Sb-terminated surfaces, all the components of the Si 2p core level related to the clean surface have disappeared, and one new Sb-induced component could be identified at a binding energy +0.20±0.01 eV with respect to the bulk peak. On the Sb-1×1 reconstruction, we found a very narrow bulk component [Gaussian full-width half maximum (FWHM) of 150 meV and Lorentzian FWHM of 85 meV], indicative of an ideal bulk termination. On the Sb-2×1 reconstruction, a broader bulk component is needed to fit the Si 2p line (Gaussian FWHM of 180 meV), indicative of some reorganization of the topmost silicon atoms following Sb–Sb dimers formation. A small component, probably due to local disorder, is present on the high-kinetic-energy side for both surfaces at −0.2 eV. The Sb 4d core-level spectrum is well represented by one doublet, thus suggesting that each Sb atom is adsorbed in a unique environment, i.e. there is no multisite adsorption.