Silicon surface reconstruction lost upon cobalt adsorption

We have studied the room-temperature adsorption of cobalt in the range of submonolayer coverages on a reconstructed Si(100)2×1 surface. The measurements were performed by methods of high-resolution (∼140 meV) photoelectron spectroscopy using synchrotron radiation (hν=130 eV). An analysis of changes in the Si 2p line shape in the course of cobalt deposition showed that the metal adsorption leads to the loss of the initial substrate surface reconstruction. The results are interpreted using a model whereby adatoms arriving at the silicon surface are incorporated into the uppermost atomic monolayer, occupying positions between four Si atoms and forming rows parallel to the 〈110〉 directions in the substrate.