Plasmonic Nanowelding Based On The Photothermal Effect

Nanowelding of nanowires opens up a new emerging set of applications in transparent conductors, thin-film solar cells, nanocatalysis, cancer therapy and nanoscale patterning. In particular, nanowire-based electronic and photonic circuits may significantly enhance the performance through welding of nanowires. However, previous works are mostly focused on large-scale nanowire meshes and large area welding, the nanowelding for functional electronics and photonics devices is much less studied but highly demanded. This paper first introduces the fabrication process of metal nanowires, the manipulation and assembling methods, as well as the different types of excitation of surface plasmons. In the second chapter, we review the main nanowire-based functional devices at state-of-the-art, including nanowire waveguides, active and passive nanophotonic devices. The nanowire-joining methods proposed by researchers recently are then presented in Chapter Three, which deal with two categories:nanowire-nanowire joining and nanowire networks joining. Finally, we develop a novel plasmonic nanowelding method based on the photothermal effect. The surface plasmon resonance occurs when the structures are shined by a focused continuous-wave laser beam, which further transfers the light energy into heat energy. This localized heat causes the nanowire to be surface-melted, leading to the welding of two nanowires. It is shown that the illumination position is a critical factor for the nanowelding process, and our thermodynamic analysis confirms the finding. Our nanowelding technique shows great potentials for high-performance electronic and photonic devices based on nanowires, such as nanoelectronic circuits and plasmonic nanodevices.