Growth of Ag nanowires on Au-pre-facetted 4° vicinal Si(0 0 1)

Abstract

We studied the self-assembly of wire-shaped Ag islands at high temperature with low energy electron microscopy and photoemission electron microscopy. A Au-faceted vicinal Si(001) surface was used as a substrate. The initial Ag deposit at 600–620°C induces a surface phase change from the (5×3.2) reconstruction of the Au-covered (001) terraces, to a (3×2) reconstruction, but leaves the structure of the Au-induced step bunches intact. Subsequent Ag growth produces two distinct types of 3D crystalline islands: compact and wire-like. The total Ag deposit is comprised mostly of compact islands, with only a small minority of wire-like islands. We attribute the wire formation to local step bunches that create the proper quasi-one-dimensional diffusion environment for the Ag islands to grow with a high aspect ratio.