The Application Research And Adjustment On Plasma Coupling Of Curved Surface Micro-nanostructure

Since the discovery of the SERS effect on roughed silver elec-trode surface,many studies have been conducted to explore diverse promising SERS substrates.Currently,most investigations have been focused on exploring various nanostructures with different shapes,sizes and nanogaps between nano-particles so as to achieve high SERS detection sensitivity.The performance of the substrate is a crucial factor for practical application.Therefore,how to fabricate a valuable SERS substrate remains a challenge on the road.After a period of study found that the nature of the nanocomposite material is good,and it provides researchers with a promising direction.In this paper,we use the magnetron sputtering to prepare a"pillar-cap"nanostructure on the colloidal template,in which the high-density hot spots are generated by heating Ag/SiO₂multilayer.A corona-like structure consisting of SiO₂-trapped Ag nanoparticles forms on the surface of nanopillar-cap array after annealing.The corona-like structure and nanoparticle sizes can be modulated by annealing.With the increasing temperature,the SiO2-trapped Ag nanoparticles grow from 2 nm to 5 nm.In comparison with as-fabricated Ag/SiO₂ multilayer,the annealed multilayers enhance the plasmon coupling and result high SERS intensity.The nanopillar-cap arrays annealed at 600?show the roughest surface,from which the strongest SERS signals are observed,about one order of magnitude higher than that of as-fabricated substrate.We provide a simple,scalable method for preparation of Ag/SiO₂ multilayer array for SERS applications and other plasma technologies,such as plasma photocatalysis.Secondly,the diameter 200 nm polystyrene spheres array as the substrate,and combine plasma etching with magnetron sputtering technology,prepared Ag nanocaps,nanocaps-nanotriangles,and nanorings-nanoparticles with high density of hot spots.It is easy to change the structure by controlling the etching time of PS colloid spheres array in silver nanobowls.The strongest SERS signals are observed in the hybrid array of silver nanocaps and nanotriangles?etched for 120 s?,for which the EF is estimated to be1.87×10⁵.Experimental results indicate that these SERS signals are reproducible and uniform across the sample surface.The FDTD simulation demonstrates that the large SERS signals stem from the high density of hot spots and enhanced electromagnetic field.This work provides a promising way to prepare the SERS-active substrates with good performance.Finally,we prepared Ag-SiO₂ nanobowl substrate through self-assembly method,etching technology and magnetron sputtering technology.The bowl diameter is controlled by changing the etching time.The incident light in the pore structure couple with the metal cavity and produced localized surface plasmon resonance.In addition to,there are a lot of hot spots on the wall of the bowl and the gaps between the bowls.We choose 4-MBA as a probe molecule to detecte SERS properties of the substrate and get different SERS enhancement demonstrate it has highly SERS activity,and it can be applied to molecular detection and recognition technology.