The effect of surface morphology upon the optical response of Au(1 1 0)

The effect of surface morphology upon the optical response of Au(1 1 0) has been studied using reflection anisotropy spectroscopy (RAS) and scanning tunnelling microscopy (STM). Starting from a clean and well-characterised Au(1 1 0)-(1 × 2) surface, changes in surface morphology due to increasing Ar ion bombardment have been observed using STM and correlated to changes in the RA spectrum. It is found that the RA spectrum is particularly sensitive to surface morphology in the photon energy region 3.0–5.0 eV. The study highlights the sensitivity of surface optical properties to surface structure and reveals the length scale on which surface roughness starts to influence the RA response.