Capillary assisted particle assembly for high aspect ratio nanorods

New developments in nanoparticle synthesis is opening new opportunities in bottom-up assembly. Indeed, monocrystalline and functionalized nanoparticles allow fabrication of metamaterials such as plasmonics and nanogap electrodes. Among the bottom up assembly techniques, capillary-assisted Particle Assembly (CAPA) allows precise placement of nanoparticles on a patterned substrate. This process has been proven to be able to produce high assembly yield for a wide variety of particle configuration. However, while several papers detail the effect of the substrate geometry to assemble nanospheres and small nanorods, few information is available to describe the limits of the nanorods size to guarantee a successful assembly. In this article, CAPA is used to assemble nanorods with three different aspect ratio. To limit the number of parameters, the focus is put on how the assembly traps' dimension affect the assembly yield. The result is used to determine the feasibility of consistently manufacturing nanogap antennas or electrodes from this method.