Effect of valency in metal adsorption on Si(111): The case of Sb on the cleaved surface

Sb adsorption on Si(111)2×1 surfaces in ultrahigh vacuum is studied by LEED, Auger and photoemission yield spectroscopies. The results are compared to the adsorption of lower valency elements In and Sn. A Volmer-Weber growth process with no ordered structure at low coverage is observed, different from the In and Sn cases. Ionization energy, band bending and surface state density show also somewhat different behaviour from those of In and Sn but consistent with the growth process and the formation of covalent bonds at the abrupt interface. High initial surface mobility of Sb has been observed.