2018/11/19 by Martin Rothe, Rothe, Martin, Yuhang Zhao +16
Engineering · Physics and Astronomy · #Plasmonic and Surface Plasmon Research #Photonic and Optical Devices #Photonic Crystals and Applications
paper · pdf · doi:10.48550/arxiv.1811.07671
Metal nanoparticles are the most frequently used nanostructures in\nplasmonics. However, besides nanoparticles, metal nanowires feature several\nadvantages for applications. Their elongation offers a larger interaction\nvolume, their resonances can reach higher quality factors, and their mode\nstructure provides better coupling into integrated hybrid dielectric-plasmonic\ncircuits. It is crucial though, to control the distance of the wire to a\nsupporting substrate, to another metal layer or to active materials with\nsub-nanometer precision. A dielectric coating can be utilized for distance\ncontrol, but it must not degrade the plasmonic properties. In this paper, we\nintroduce a controlled synthesis and coating approach for silver nanowires to\nfulfill these demands. We synthesize and characterize silver nanowires of\naround 70 nm in diameter. These nanowires are coated with nm-sized silica\nshells using a modified St "ober method to achieve a homogeneous and smooth\nsurface quality. We use transmission electron microscopy, dark-field microscopy\nand electron-energy loss spectroscopy to study morphology and plasmonic\nresonances of individual nanowires and quantify the influence of the silica\ncoating. Thorough numerical simulations support the experimental findings\nshowing that the coating does not deteriorate the plasmonic properties and thus\nintroduce silver nanowires as usable building blocks for integrated hybrid\nplasmonic systems.\n