Capillary particle assembly (CAPA) for plasmonic devices

Signicant progress has been made to synthesis colloidal particles capable of controlling shape , dimensions and structures. These nanoparticles placement and integration on sur- faces is the main challenges of engineering approaches. Here, we investigate the comple- mentary methods to assemble nanoparticles in two and three dimensional substrate with dierent shape, size and orientation.using hydrophobic substrate to trap and organise par- ticles inside the trenches by capillary forces. we demonstrate that temperature, wetting properties and substrate geometry can be control to achieve high yield assembly with abil- ity to control the arbitrary orientation of particles(nano rods). substrate temperature factor can induce the local phase transition which conne the nanoparticles at three phase contact line required for high yield assembly. wetting properties were determined by silanization of substrate and adjusting surfactant con- centration.Sodium dodecylbenzenesulfonate( SDBS) and cetyltrimethyl ammonium bromide (CTAB) surfactant critical micelle concentration were measured and tuned respectively to stabilise nanospheres and nano rods colloidal solu- tion. substrate template were modied for nano rods to achieve accurate angle orientation by etching assessment and design fabrication (funnel prole with HSQ wall). etching pa- rameters were modied to get accurate nanoscale prole with respect to the design for both silicon and silicon oxide substrate. Eect of substrate orientation and size on the assembly yield were characterised. substrate geometry eect on angular distribution were measured as well.high yield and accurate connement were achieved on the funnel prole templates.the feasibility and reproducibility of this method is demonstrated by assembling nano particles into large area, non close packed arrays. furthermore nanoparticles that are deterministically assembled have the potential to function as nano-plasmonic antennas de- vices. micro uidic chip were fabricated to use in the assembly site to overcome volume limitation in the assembly.