LEED-AES-TDS characterization of Sb overlayers on GaAs(110)

The GaAs(110)-Sb system is studied with Auger Electron Spectroscopy, Low Energy Electron Diffraction, Soft X-Ray Photoemission Spectroscopy and Thermal Desorption. Sb evaporated at room temperature forms a continuous film and a sharp interface with the substrate. For a coverage of one monolayer, LEED indicates a well ordered (1 × 1) structure which produces diffracted intensities very different from those measured from the clean substrate. Thermal desorption experiments show the particularly strong bonding between the first Sb monolayer and the substrate, confirming the large chemical stability observed during photoemission experiments. Two types of structures were considered for GaAs(110)-Sb(1 ML). Sb chains extending along the (110) direction, parallel and anti-parallel to the top layer Ga-As chains, and Sb dimers placed above the surface with one Sb bond to the surface Ga. The preliminary LEED analysis favors the later model.