UV Plasmonic Behavior of Various Metal Nanoparticles in the Near- and Far-Field Regimes: Geometry and Substrate Effects

The practical efficacy of technologically promising metals for use in ultraviolet plasmonics (3-6 eV) is assessed by an exhaustive numerical analysis. This begins with estimates of the near- and far-field electromagnetic enhancement factors of isolated hemispherical and spherical metallic nanoparticles deposited on typical dielectric substrates like sapphire, from which the potential of each metal for plasmonic applications may be ascertained. The ultraviolet plasmonic behavior of aluminum, chromium, copper, gallium, indium, magnesium, palladium, platinum, rhodium, ruthenium, titanium, and tungsten was compared with the well-known behavior of gold and silver in the visible. After exploring this behavior for each metal as a function of nanoparticle shape and size, the deleterious effect caused by the metal's native oxide is considered, and the potential for applications such as surface-enhanced Raman spectroscopy, accelerated photodegradation and photocatalysis is addressed.