Transversal plasmon resonance observed in tapered silicon nanowires

It has been recently demonstrated in literature that silicon nanowires (Si-NWs) with a cylindrical shape sustain longitudinal and transversal plasmon resonances. In this work, we present the results about the electron energy loss spectroscopy on Si-NWs with tapered morphology. The Si-NWs present a length of about 300 nm and a diameter, at the base, of around 15 nm, while at the center, of approximately 12 nm. Despite the different geometry, the results confirm the presence of transversal plasmonic resonance, as in the previous study. However, the presence of a continuous signal extending all along the Si-NWs length, and for several energies, is observed here for the first time.