Activity: Talk or presentation › Oral presentation
Oblique incidence ion sputtering has become a widely used method for the creation of highly regular patterns of lines and dots. On a Ag(001) surface oblique incidence sputtering creates a ripple pattern that exhibits plasmonic features. The photon energy of the plasmonic feature depends on the ripple periodicity. The development of these anisotropic features was measured in-situ with the optical technique Reflection Anisotropy Spectroscopy (RAS) for 2 keV Ar ions with a flux of a few µ A/cm2 in a temperature range of 300 - 420K. With RAS, a periodicity of ripples above 200 nm is measured by a shift in photon energy of the plasmon resonance. Features with a smaller periodicity show a plasmon resonance around 3.65 eV. The Rayleigh-Rice description for scattering from a slightly rough surface enables to relate the measured plasmonic feature quantitatively to the ripple’s rms, wavelength and wavelength distribution. Ripple patterns created with ions at 70∘ and 80∘ polar angles of incidence are compared. High resolution LEED measurements after sputtering are used to determine the facet angles of the created ripples.