Engineering Localized Surface Plasmon Interactions in Gold by Silicon Nanowire for Enhanced Heating and Photocatalysis

The field of plasmonics has attracted considerable attention in recent years because of potential applications in various fields such as nanophotonics, photovoltaics, energy conversion, catalysis, and therapeutics. It is becoming increasing clear that intrinsic high losses associated with plasmons can be utilized to create new device concepts to harvest the generated heat. It is therefore important to design cavities, which can harvest optical excitations efficiently to generate heat. We report a highly engineered nanowire cavity, which utilizes a high dielectric silicon core with a thin plasmonic film (Au) to create an effective metallic cavity to strongly confine light, which when coupled with localized surface plasmons in the nanoparticles of the thin metal film produces exceptionally high temperatures upon laser irradiation. Raman spectroscopy of the silicon core enables precise measurements of the cavity temperature, which can reach values as high as 1000 K. The same Si-Au cavity with enhanced plasmonic activity when coupled with TiO