1-D nanostructures grown on the Si(5512) surface

We have used scanning tunneling microscopy (STM) to study the growth behavi or of noble metals deposited on the high-index Si(5 5 12) surface. This uni que surface is tilted 30.5 degrees down from (0 0 1) and forms a single-dom ain reconstruction composed of row-like structures. When low coverages (<0. 25 ML) of noble metals such as Ag and Au are deposited onto Si(5 5 12) and moderately annealed (similar to 450 degreesC), they form overlayer "nanowir es" with the periodicity of the Si surface (54 nm). It is the preferential reactivity of the underlying Si row structures that results in this well-or dered growth behavior. At higher coverages and temperatures, however, these metals can cause significant restructuring of the surface that leads to th e creation of neighboring facet planes. Ag forms nanoscale sawtooth facets at coverages above 0.25 ML, but they are relatively narrow (5-10 nm wide) a nd do not cause the surface to undergo a dramatic restructuring. In contras t, Au deposition induces significant faceting of the surface, resulting in the formation of (1 1 3), (2 2 5), (3 3 7), (5 5 11), or (7 7 15) facet pla nes composed of periodic 1-D nanostructures. (C) 2001 Elsevier Science B.V. All rights reserved.