Adsorption of partially and fully dissociated H2S molecules on the Si(001) and
Ge(001) surfaces
School of Physics, University of Exeter, Stocker Road, Exeter
EX4 4QL, UK
Abstract
Ab initio calculations, based on pseudopotentials and the
density functional theory, have been made to investigate the
equilibrium atomic geometry, electronic states and bonding of the
H2S molecule on the Si(001) and Ge(001) surfaces within two
dissociative adsorption geometries. First we consider adsorption of
partially dissociated species (SH)- and H+ onto
the Si- or Ge-dimer with a (1 x 2) surface periodicity. Secondly, we
consider adsorption of fully dissociated species S and 2H on the
surface with a (1 x 2) periodicity but without dimer formation. In
general, the adsorption of H2S on the Si(001) and Ge(001)
surfaces shows similar behaviour. For both geometries studied here,
the fundamental band gap is free of surface states, with the highest
occupied state lying below the valence band maximum.