Effect of crossing geometry on the plasmonic behavior of dielectric core/metal sheath nanowires

We have shown that dielectric/metal composite nanowires exhibit very strong surface enhanced Raman spectroscopy (SERS) signals when arranged in a random three-dimensional geometry. Since the intersections of the nanowires are critical in generating the high electric fields necessary for this enhancement, we are investigating this effect under more controlled conditions. We examined nanowire arrays formed by e-beam lithography and we have examined the plasmonic effects, both longitudinal and transverse, due to changes in crossing geometry by specific placements of dielectric/metal nanowires on these arrays. Results indicate significant angular effects on the SERS enhancement supported by electric field calculations.