Preparation And Optical Properties Of Metal/High-Permittivity Hybrid Nanoparticles

Surface enhancement Raman scattering(SERS)as a specific material analysis technology,because of its characteristics,for example,Raman spectrum with a wide range,which can detect inorganic and organic matter.What's more,it has a little effect on aqueous solution materials,so it can analyze the solution of the materials.The Raman peak is sharp and clear so that the ability of test samples can be accurate to micron level,which can adapt to analyze the material with a small size,therefore,it also has a low requirement for sample size and shape;at the same time,the process of test can be repeated and low damage to the sample.Since its appearance,SERS has been widely applied in chemistry,biology and environmental science.So far,the active substrate of SERS is generally noble metal material,such as gold,silver,copper and other metals,however,those metal nano-materials are easy to be oxidized in the air,which leads to the samples difficult to preserve.Consequencely,due to the shortcomings of single metal nanoparticles that traditional substrates always are oxidized easily,we come up witn a typical substrate that it composes metal with high-permittivity materials for the study of SERS in this paper.For one thing,through using rhodamine molecules(R6G)as probe molecules for testing in the experiment,we prove that the metal and high-permittivity hybrid nanoparticles has high stability,thus it greatly improve the service life of the samples.For another,compared with the traditional substrate,the sensitivity of this hybrid nanoparticles gets improved well,and the Raman signal of R6 G molecules also becomes enhanced.What's more,in this paper,the process of preparating the hybrid substrate is convienent,and we use the R6 G molecules to characterize the samples with the properties of Raman spectrum,the results indicates the hybrid substrate we prepared is highly sensitive.The paper mainly includes the following aspects:1.Based on the traditional metal substrate for SERS,we design a type of gold and silicon nanostructures as a new substrate for enhancing Raman scattering.By changing the parameters of the sample structure,such as particles size and distance with each other,then,we can realize the optical regulation of sample structure.As well as,compared to the traditional metal substrate for SERS that are not contained with high-permittivity materials,the composite structure can greatly improve the singnal of Raman spectrum with R6 G molecules in this paper.2.In our experiment,we obtain different thickness of gold film with magnetron sputtering deposition,then,it can form gold nanoparticles(AuNPs)after thermally annealing treatment,finally,we deposit ultra-thin Si layer onto the sample,in this process,we change the size of the metal nanoparticles and the thickness of high-permittivity materials through controlling the temperature of annealing,as a result,we can explore the best conditions of the substrate for SERS,in this method,we can get substrate with the large area and high stability.3.We design the metal-high-permittivity hybrid nanostructures that can effectively detect the Raman spectum of fluorescence dye molecules of R6 G,furthermore,we can receive the minimum detection limit of this structure by changing the concentration of R6 G molecules adsorbed on the sample.The hybrid nanostructures we prepared can be used for biomedicine,food detection and other aspects in this way.