The influence of surface steps on the formation of Ag-induced reconstructions on Si(111)

Using scanning tunneling microscopy, the influence of Si(111) surface steps on the formation of Ag-induced reconstructions was investigated. For low Ag coverage, both the 3 x 1 and the √ 3 x 3 structures form. at the upper step edge while for increasing coverage, the √ 3 x √ 3 areas grow at the expense of the 3 x 1 and 7 x 7 regions. This growth critically depends on the height of the adjacent step. For a monoatomic step, the √ 3 x √ 3 patch grows uniformly (at the same level) over the upper and lower terrace resulting in a wandering of the step, while higher steps are splitted into two levels due to the formation of high and low Ag-covered areas. Furthermore, a quantitative description of the growth of the √ 3 x √ 3 patches is given, based on the shape evolution of the √ 3 x √-3 regions and from the analysis of antiphase boundaries. © 2005 American Institute of Physics.