Self-assembly of highly ordered plasmonic gallium nanoparticles driven by nanopatterning

Abstract

Ordered porous anodic alumina has become a popular template for the nanopatterning of different materials due to its ease for manufacturing. However, an aluminium nanopatterned template obtained after removing the alumina has not been widely used despite it maintains its hexagonal periodicity. In this work, we use that nanopatterned aluminium to deposit gallium nanoparticles (NPs) by thermal evaporation, resulting in highly ordered arrays of spherical-like NPs. The size and shape of the NPs are investigated by scanning electron microscopy in order to best match the template pattern. Furthermore, the improvement of the plasmonic properties of the NPs is confirmed by spectroscopic ellipsometry compared to the ones deposited on silicon substrates. Reported results show that the plasmonic intensity is increased, as well as the full width at half maximum reducing. This effect could have a direct impact on the sensing applications of these NPs.