| Summary: | Raman spectroscopic studies on individual single-walled carbon nanotubes (SWNTs) were conducted by analysing the Radial Breathing Modes (RBMs) and other Raman bands of SWNTs prepared both from separating commercial SWNTs and from a chemical vapour deposition (CVD) process. Tentative chirality assignments of the CVD grown SWNTs were made by combining the findings from the RBM spectra and the G- or G'-band spectra obtained using various laser energies, and the diameter distributions of the samples were determined. In addition, polarised Raman studies were performed on the CVD grown SWNTs, and samples containing aligned SWNTs were also investigated to determine the degree of the alignment and to correlate with FE-SEM image analysis of the samples. SWNT networks decorated with Ag nanoparticles using electrochemical deposition were characterised using various laser wavelengths to probe the surface-enhanced Raman scattering (SERS) effect of this nanostructure. The Raman intensity enhancements of the SWNTs were found to be dependent on the density and size of the Ag particles, and the dependence of the enhancement varied with the laser energies used. The findings were further correlated with the localised surface plasmon resonance (LSPR) of the Ag nanoparticles, showing that the stimulation of the LSPR using various lasers wavelength is responsible for the different Raman intensity enhancement of the SWNTs. The SWNT/Ag nanostructure was also used as a SERS substrate for the detection of pyridine absorbed on the substrate. The results demonstrate the possibility of using this nanostructure for generic SERS sensing purposes.
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