Preparation Of Silicon Nanowire Structure And Its SERS Performance

The relevant agencies have gradually increased the supervision of environmental problems and food safety,because they are related to everyone's health,but most of the harmful substances are traceable,so the detection means are highly in demand.There are many problems in the conventional detection methods,such as low detection sensitivity,complex operation,the introduction of other substances,however the surface-enhanced Raman scattering(SERS)technology has proposed to break the bottleneck of the detection technology,this method has been widely used because of its simple operation,high sensitivity and non-destructive testing,so it is positive to seek effective ways to improve the SERS performance.Si NWs structure was prepared by metal assisted chemical etching(MACE)method.The surface of Si NWs was modified by silver nanoparticles to form silver modified nanowires(Ag @ Si NWs)composite structure,and finally the effect of morphological parameters of Si NWs on the SERS performance of Ag @ Si NWs composite substrate was studied.Firstly,the silver nanoparticles were deposited on the surface of the silicon by immersion method.The results showed that the size of the silver nanoparticles increased with the increase of the deposition time.The high temperature annealing could make the distribution of the silver nanoparticles more uniform.Secondly,we prepared silicon nanowires structure by metal-assisted chemical etching,and the pre-prepared silver nanoparticles acted as the catalyst.The results showed that the ratio of etching solution,etching time,etching temperature and silicon substrate orientation could affect the morphology of Si NWs structure.Therefore,we have obtained silicon nanowire structure of different line height,line diameter,line spacing and the line direction by adjusting these factors.Lastly,silver nanoparticles were deposited on the surface of Si NWs structure with different morphology by magnetron sputtering method to form different Ag@Si NWs composite structures.The detection results of Raman signal of 10-5 M R6 G solution showed that the line diameter and line spacing had a great influence on the SERS performance of the substrate,thus adjusting the line diameter to the line spacing ratio could be an effective way to improve the SERS performance of the Ag @ Si NWs substrate.