Metal Nanoparticle-Nanowire Assisted SERS On Metal Film

Surface plasmon polaritons(SPPs) are propagating electromagnetic waves associated with the collective motions of the conduction electrons confined to the metal-dielectric interfaces. Metal nanoparticles are widely used because localized surface plasmon resonance can generate enormous electromagnetic field enhancement on nanoparticles. In metal nanostructures- film systems, redistribution of electromagnetic field exhibits excellent ability to limit light. It is significant to surface enhanced Raman scattering(SERS) of two-dimensional material and molecular. In this paper, SERS of single-molecule is studied in metal nanoparticles- nanowire structures. Combining theory and experiment, we discussed SERS?catalysis recation and effect of substrate on SERS.Surface-enhanced Raman scattering(SERS) effect refers the phenomenon that Raman scattering signal of the adsorbed molecules is stronger than ordinary Raman scattering signal in the surface of rough metal. Enhanced Raman can overcome the shortcomings of low sensitivity. Some structural information can be obtained accurately through enhanced Raman, but it is difficult to get by ordinary Raman. It is widely used in surface studies, interfacial adsorption, biological molecules oriented and other fields. Metal nanoparticles-nanowires and film system was designed in this paper. By this system, Raman scattering signals of 4-nitrobenzenethiol(4NBT) and p-aminothiophenol(PATP) absorbed on metal surface were significantly enhanced.Surface plasmon can drive surface-catalyzed reactions of molecules absorbed on metal surface. A large number of experimental and theoretical results show that PATP molecules and 4NBT molecules can be coupled generated p, p'-dimercaptoazobenzene(DMAB) under the action of the electromagnetic field. The results of the catalytic reaction can be expressed by surface-enhanced Raman scattering spectroscopy. The results indicated that the SERS intensity was much greater at the adjacent part of the nanoparticle-nanowire system for the electromagnetic field distribution. Furthermore, the results also pointed out the shape independence of the nanoparticle in this phenomenon. This result reduces the limitations of such structural in applications. We chose different substrates to do comparison tests for the study of substrate-dependent. Since the surface roughness is different of metal and non-metallic film. We predict the effect of enhanced and catalytic were different for the same molecule. Experimental results shown the Raman enhancement effect of molecules were remarkable on metal surfaces.