Coordination determination of In on Si(100) from synchrotron photoemission studies

High-resolution core-level photoemission spectroscopy was used to study the initial growth and interaction of In on Si(100). The In---Si bonding coordination number, determined by quantification of the number of Si surface atoms selectively modified in the presence of an In adatom, is 3 for very low In coverages, and decreases to 2 for (1/2) -monolayer coverage. The results are consistent with a structural model deduced from electron diffraction, Auger, and scanning electron microscopy studies.