Author: Dietrich R.T. Zahn
Requested Type: Either Oral or Poster
Submitted: 2015-03-30 15:09:53
Co-authors: R. Rodriguez, S. Moras, E. Sheremet
Technische Universität Chemnitz
This work aims at a systematic comparison of enhancement factors in surface enhanced Raman scattering (SERS) experiments by preparing ultra-thin films of semiconducting molecules with identical thicknesses (2 nm of cobalt phthalocyanine) by molecular beam deposition on arrays of ordered metallic nanostructures. The latter were fabricated by nanosphere lithography using 450 nm spheres on silicon substrates. Subsequently metals were evaporated using the closed packed sphere monolayer as shadow mask. After removal of the spheres regular arrays of triangular shaped nanostructures were obtained. Here we compare the results obtained for the conventional SERS metals gold and silver with copper and aluminium. Cu and Al nanostructures show Raman enhancements and chemical stability similar to those obtained with Au and Ag. When the excitation wavelength is in the green spectral range Al performs surprisingly well as Al should be the worst choice of all metals when taking into account its dielectric function. Under red excitation Cu provides an enhancement close to that of Au and considerably higher enhancement than Ag and Al. In addition to the photochemical and catalytic properties of Cu and the convenience of Al, these results are promising for large-scale plasmonic applications using metals compatible with mass-production fabrication in microelectronics.