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

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.