ABSTRACT
A combined theoretical and experimental study on the adsorption of an isolated benzonitrile molecule on the Si(001) surface, followed by the adsorption of Al (group III), Pb (carbon group) and Ag (transition metal) is presented. It is shown that two new adsorption sites with enhanced reactivity are formed on the surface in the vicinity of the pre-adsorbed molecule. This is evidenced by the increase of the calculated binding energy of the metallic ad-atoms adsorbed at these sites. Experimentally, this enhanced local reactivity of the modified surface is only partially retained when more metallic atoms are adsorbed on the modified surface at room temperature. This is evidenced by the formation of 1-dimensional atomic chains (Pb, Al) attached to one side of the pre-adsorbed molecule.
ABSTRACT
Photofield emission (PFE) measurements are employed to examine modifications of the surface electronic structure of the tungsten (1 1 1) facet upon deposition of thin films (1-3 monolayers) of titanium. With the help of DFT simulations, the observed PFE features are interpreted as adsorbate-induced resonance states with energies just below the Fermi level, localized predominantly at the exposed surface atoms. Comparison between the computed surface DOS distributions and the measured PFE spectra is also used to verify various possible arrangements of the Ti adatoms, supporting the DFT-favored model of Ti growth in registry with the W(1 1 1) substrate until a full physical overlayer of the adsorbate is completed.
ABSTRACT
Photofield emission (PFE) measurements are employed to examine modifications of the surface electronic structure of the tungsten (111) facet upon deposition of thin films (1-3 monolayers) of titanium. With the help of DFT simulations, the observed PFE features are interpreted as adsorbate-induced resonance states with energies just below the Fermi level, localized predominantly at the exposed surface atoms. Comparison between the computed surface DOS distributions and the measured PFE spectra is also used to verify various possible arrangements of the Ti adatoms, supporting the DFT-favored model of Ti growth in registry with the W(111) substrate until a full physical overlayer of the adsorbate is completed.
