AVS 45th International Symposium
    Surface Science Division Monday Sessions
       Session SS1-MoM

Paper SS1-MoM7
Fermi Surface and Metallization of the Ag/Si(111)7x7 Interface

Monday, November 2, 1998, 10:20 am, Room 308

Session: Issues in Surface Electronic Structure
Presenter: J. Avila, LURE, Centre Universitaire Paris Sud and ICMM, France
Authors: J. Avila, LURE, Centre Universitaire Paris Sud and ICMM, France
M. DeSeta, III Univerista di Roma, Italy
M.C. Asensio, LURE, Centre Universitaire Paris Sud and ICMM, France
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The determination of the metallization onset of metal/semiconductor interfaces is an important goal for diverse applications as well as for its fundamental interest. In this field, the early stage of nucleation and growth plays an essential role in determining the final morphology and electronic structure of the interfaces. In this work, we address this particular issue for the epitaxial growth of silver overlayers on Si(111)7x7 surfaces studied by LEED, Photoelectron Diffraction and High Energy Resolution Angular Resolved Photoemission. The films were prepared by Ag deposition at room temperature and the silicon substrates were chemically treated previously to be introduced to the ultra high vacuum system. The evolution of the valence band as a function of the silver coverage, at particular high symmetry points of the reciprocal space, has put clearly in evidence the onset of the metallization of this interface. The presence of Si features even at 4 silver monolayers is consistent with the existence of Ag islands since the first layers. The Fermi Surface of the Ag/Si(111)7x7 interface, measured in situ, shows the coexistence of two domains of Ag(111) rotated 60° each others. In addition, the valence bands recorded along the @GAMMA@K, @GAMMA@M and @GAMMA@M' azimuths are in excellent agreement with band theoretical calculations.