Design And Research Of Surface-Enhanced Raman Scattering Substrate Based On Nanoarray Structure

Surface-enhanced Raman scattering(SERS),as a new method of spectral detection,overcomes the shortcoming of low Raman scattering intensity.SERS has the characteristic of high sensitivity,is not easily interfered by fluorescence and can provide the characteristic spectrum of the detector.It has been widely used in the field of low concentration detection and single molecule level detection.The relationship between hot spots and excitation wavelength of Au nanoparticles dimer or Ag nanoparticles dimer is discussed firstly in this paper.The result shows that the electric field enhancement factor between nanoparticles and the location of resonance peak changes when the geometric parameters of metal nanoparticles change.Then,a substrate based on triangular wedge enhanced Raman spectroscopy(WERS)is proposed.The electric field enhancement factor and the effective mode field radius with varying geometric parameters and excitation wavelength are theoretically analyzed.The average SERS enhancement factor of WERS can reach up to 1.824×10~9 at the optimal parameter conditions.Furthermore,this paper discusses the practical application conditions of WERS substrate and proposes a possible fabrication protocol.Finally,the SERS effect of the silver nanoparticles/pyramid silicon(Ag NPs/PSi)substrate is discussed.The influence of electric field enhancement factor with varying geometric parameters of nanoparticles and excitation wavelength is theoretically analyzed and the maximum SERS enhancement factor can reach up to 2.401×10~7.The sensitivity,repeatability and stability of Ag NPs/PSi enhanced substrate are validated by selecting crystal violet as the Raman probe.In addition,the test of mercury ions is designed by using Ag NPs/PSi enhanced substrate.When the spectral signal"from on to off",the existence of mercury ions can be proved by choosing sodium 2-mercaptoethanesulfonate as masking agent.This paper not only makes a detailed analysis of the correlation between Au nanoparticles or Ag nanoparticles and wavelength,which provides a reference for the selection of metallic materials at different wavelengths,but also proposes and studies two new nanoarray SERS substrates which can provide high SERS enhancement factors.These conclusions provide a new practical method for the development of SERS detection technology,which can be widely used in cell detection,food safety and environmental monitoring.