Core-level photoemission studies of the sulphur-terminated Si(100) surface

A core-level photoemission spectroscopy study of the deposition of sulphur on the Si(100) surface has been performed. The sulphur is deposited from an electrochemical cell onto the clean Si surface at 1200–1300 K in an ultra-high vacuum. The Si surface dimers are broken, and the sulphur-terminated surface displays a (1×1) reconstruction. Analysis of the core-level spectra reveals that both +1 and +2 oxidation states of the silicon are present, while the adsorbed sulphur exists in a single well-defined chemical state. The results are interpreted in terms of a submonolayer sulphur coverage, approximating to 3/4 monolayer, displaying a (1×1) bulk-like surface termination.