Using surface and interface optics to probe the capping, with amorphous Si, of Au atomchains grown on vicinal Si(111)

Abstract

The distinct optical signatures of aligned single and double Au atom chain structures,grown on vicinal Si(111) substrates, have been identified using reflectance anisotropyspectroscopy (RAS). Deposition of 0.04 monolayers (ML) of amorphous Si (a-Si) atroom temperature perturbs the anisotropic optical response of the double chainstructure. By one third of a monolayer, no significant optical anisotropy associatedwith the chains remains. No anisotropic response re-emerges at higher coverages,up to 4.6 nm (14.5 ML) where there is recent evidence that the crystal structureof the double chain phase is maintained under the cap. The RAS results showthat the anisotropic properties of the phase are quenched by a-Si adsorption,even though the crystal structure of the capped phase appears to be preserved.