AVS 53rd International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP16
Chemisorption of Cl on Si(114)

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Surface Science Poster Session
Presenter: R.E. Butera, University of Illinois at Urbana-Champaign
Authors: R.E. Butera, University of Illinois at Urbana-Champaign
A. Agrawal, University of Illinois at Urbana-Champaign
J.H. Weaver, University of Illinois at Urbana-Champaign
Correspondent: Click to Email
The dissociative chemisorption of Cl@sub 2@ on Si(114) has been studied at room temperature using scanning tunneling microscopy. The three distinct structural units of the clean Si(114) surface (monomer, dimer, and tetramer) make it an ideal template to study the selective adsorption of a reactive species on a semiconductor surface. A mild anneal to 400-500 K following Cl@sub 2@ exposure allows the adsorbed Cl to interrogate the surface to find the most energetically favored adsorption site. With increasing exposure, Cl adsorbs on the monomer (@theta@@sub Cl@ @<=@ 0.25 ML), then the dimer (0.25 ML @<=@ @theta@@sub Cl@ @<=@ 0.50 ML), and finally the tetramer (@theta@@sub Cl@ > 0.50 ML). The difference in reactivity is attributed to @pi@ bonds within the dimer and tetramer units but not along the monomer row. The low reactivity of the tetramers reflects the presence of a @pi@-bonded ring-like structure composed of single @pi@ bonds along each of the tetramer arms as well as between the tetramer bridge. The adsorption of Cl removes the buckling of each surface unit transforming the surface from a mixed (2x1)-c(2x2) phase to a complete (2x1) phase at @theta@@sub Cl@ = 1 ML.