Optical response of Ag-induced reconstructions on vicinal Si(111)

The optical response of the Si(I 11)-(3 x l)-Ag surface has been studied for the first time with reflectance anisotropy spectroscopy (RAS). A single domain surface was obtained by depositing < 1 ML of Ag onto a vicinal Si(I 11) substrate at 870 K. A significant optical anisotropy develops around 2.2 eV which is related to the formation of the 3 x I structure. This surface was then used as a template to grow one-dimensional (ID) arrays of Ag nanodots, and also 3D Ag islands, by depositing 0.5 ML, and higher, coverages of Ag at room temperature. RAS of these structures showed a different response in the 2.2 eV region, with a broadened and reduced anisotropy. By extending the RA spectra into the infra-red region (0.5-1.5 eV), substantial differences between the structures were observed below I eV, which may be linked to a difference in the metallic character of the nanodots and islands. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.