Study On Surface Enhanced Raman Scattering Of Aluminum Nanostructure

UV-SERS has higher sensitivity in detecting DNA molecules with absorption band in ultraviolet region.Besides,it can avoid harmful fluorescence background,which offers an effective and precise way to obtain vibration information in complex mixtures.For metallic materials,aluminum nanostructures can extend the LSPR response to the ultraviolet region,so it can be used in UV-SERS to effectively enhance the Raman scattering mode of probe molecules.Firstly,the basic model of aluminum nanostructures is established,and the LSPR characteristics of aluminum nanostructures are analyzed by FDTD method.The results show that the LSPR response of aluminum nanostructures can be extended to the ultraviolet region with the decrease of the size of the nanostructures.For aluminum nanostructures,aluminum nanostructures with"hot spots"possess high enhancement,and the theoretical value of electromagnetic field enhancement is as high as 7.83×10 ~6.Compared with the single larger aluminum nanoparticles,smaller and larger density particles which form a"hot spot"region yield higher enhancement.Secondly,according to the results of simulation analysis,Al nanostructures were prepared by rapid annealing self-assembly method.Based on the Volmer-Webber growth model,aluminum nanoparticles with small size and high density can be directly formed during the deposition process.With the increase of annealing temperature,the size of aluminum nanostructures increases,and with the increase of deposition thickness,the morphology of aluminum nanostructures changes from nanoparticles to long aluminum nanomounds.Finally,the UV SERS spectra of adenine were obtained on the prepared Al nanostructures,and the relationship between the SERS enhancement and the Al nanostructures was studied.The experimental results show that the SERS enhancement of aluminum nanoparticles directly formed after evaporation is the strongest,and the maximum enhancement is 3.49×10~7.Through the performance test and stability analysis of the SERS substrate,it is found that the detection limit of the substrate can reach 10~-77 M with excellent reproducibility,which is of great significance to the industrialization and large area preparation of the UV SERS substrate.