Coverage measurements of the Si(100)2 × 1:Cs and Si(100)2 × 1:K surfaces: resolution of structural models

Abstract

In this study, medium energy ion scattering has been used in conjunction with Auger electron spectroscopy and LEED to measure the saturation coverage of Cs and K on Si(100) at room temperature, for which distinct 2 × 1 surface structures are observed. Defining one monolayer as the density of Si in a single (100) crystal plane (6.78 × 1014atomscm2), the overlayer coverages in these systems are 0.97 ± 0.05 ML for Si(100)2 × 1:Cs and 0.98 ± 0.05 ML for Si(100)2 × 1:K. These results clearly discriminate between proposed models containing 0.5 and 1.0 ML alkali coverage for the saturated surface.