Plasmonic behavior of Ag/dielectric nanowires and the effect of geometry

Recently, the authors have shown that dielectric/metal composite nanowires exhibit very strong surface enhanced Raman (SERS) signals when arranged in a random three-dimensional geometry. Since they believe that the intersections of nanowires are critical in generating the high electric fields necessary for this enhancement, they have investigated the effect of crossing geometry under more controlled conditions. Thus, they will discuss the formation of nanowire arrays by in situ growth achieved by the control of nanowire material/substrate combination, as well as ex situ nanowire array formation involving e-beam lithography. They have examined the plasmonic effects, both longitudinal and transverse, due to changes in crossing geometry by specific placements of dielectric/metal nanowires on the fabricated arrays. The effects of nanowire geometry and the resulting SERS behavior show the importance of the dielectric/metal configuration, as well as the importance of nanowire angular geometry in the SERS enhancement.