Study On LSPR Regulation And Its Application In The Preparation Of Metal Nanostructure Arrays By Ion Beam Etching

Long-range ordered metal nanostructure arrays have excellent optical,electrical and magnetic properties because of their special interaction with light.In recent years,it has been widely used in surface-enhanced Raman,biosensors,optical devices and biological fields.The local surface plasmon resonance(LSPR)effect of nanostructures is mainly affected by its material,size,morphology and other factors,so the LSPR can be regulated on the nanometer scale by changing the structural parameters.In this paper,using polystyrene nanospheres as templates,a variety of periodic arrays were prepared by using the shadow effect of periodic closely arranged nanospheres,combined with magnetron sputtering and ion beam etching,and applied to polarization anisotropy.Structural color labels and biological detection and other fields.This paper mainly explores the following three aspects.(1)Construction of anisotropic Nano-cavity Array and Application of polarized SERSOrdered silver nanocavity arrays were fabricated on polystyrene templates by magnetron sputtering and ion beam etching,which are anisotropic to polarized SERS.Polarized extinction spectra and polarized Raman measurements further show the anisotropy of the nano-cavity array.The nanocavity array can be used as a substrate for polarized Raman scattering to eliminate polarization-independent background clutter.The size of the silver nano-cavity and the position of the hot spot can be adjusted by controlling the etching angle of the ion beam and the thickness of the silver film of the sample.The three-dimensional simulation results of the polarized electric field are consistent with the polarized Raman results,and the root cause of the response of the anisotropic nanostructure to the polarized light is obtained.the hot spots of the thin silver film nanocavity arrays are mainly concentrated on the three vertices of the triangular nanocavities.With the change of the direction of polarized light,the position and intensity of the hot spots change,and the hot spots of the thick silver film nanocavity arrays are coupled to the whole nanocavity.The hot spot intensity is highly responsive to polarized light.(2)LSPR Regulation and structure Color Design in Multi-level structureLight interacts with micro-nanostructures to produce structural colors.With the characteristics of energy saving,adjustable and bright color,structural color label has been applied to the fields of optical data archiving,optical document security,sensing and display technology.In the process of plasma etching,due to the shadow effect of hexagonal dense array of nanospheres,the multi-stage structures of silver cavity and PS colloidal particles can be controlled.Changing the morphology of PS or silver nano-cavity alone can fine-tune the structure color in the same color gamut,and the common change of both will lead to the expansion of the structure color gamut.PS dielectric nanospheres have a certain resonance absorption ability to light.Silver film not only increases the reflection of light,but also induces specific absorption,both of which improve the visibility of color.Based on the regulation of structural color by multi-level structure,we have prepared brightly colored optical tags.(3)Application of SERS of rhomboid synaptic structure in thiramAn efficient,repeatable and sensitive surface-enhanced Raman scattering(SERS)active substrate was fabricated by low-cost ion beam etching.The substrate structure is a diamond-shaped synaptic nano-array with uniaxial symmetry.By controlling the angle between the ion beam and the sample,the morphology of the diamond synaptic nanostructure can be controlled,and the strong electromagnetic field coupling occurs between the synapses between the adjacent nanospheres and the synapses of the nanospheres themselves.The electromagnetic field distribution of diamond-shaped synaptic nanostructures is numerically simulated by using finite-difference time-domain software(FDTD).The simulation results show the hot spot distribution area well.The SERS properties of the samples were characterized by 4-MBA probe molecules,and the rhomboid synaptic nanostructure array has a good detection effect.The nanoarray has realized the ultra-low concentration detection of pesticide thiram(10-11m).The results show that the sample has good repeatability and has great application potential in food safety.