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1.3 PHYSICAL SCIENCES
Carbon nanotubes, long, thin cylinders of carbon are intriguing structures and
have sparked much excitement in recent years. It is clear that understanding the fundamental properties of nanotubes is necessary to get a realisation of the full potential of these materials. Processing and purification on a mass scale will need to be carried out if these materials are to have large scale industrial applications and move beyond the laboratory bench. Highly sensitive, capital intensive equipment such as TEM and AFM, have been used to identify the state and morphology of tube samples as well as their levels of purity, however for large scale industrial applications there is a need for routine, high throughput, cost effective methods to give the same kind of detail. In this thesis organic solvents are used to debundle single walled nanotubes. The debundling is confirmed and the degree measured using absorption spectroscopy and also the capitally intensive and low throughput techniques, TEM and AFM. Although Raman spectroscopy is a well established technique for characterising tube bundles and single tubes little is know about what subtle changes occur in the Raman spectrum as one goes from a highly bundled state to a lower degree of bundling. In this thesis these changes are examined and the use of previously unidentified spectral markers for the degree of debundling are identified. Finally, using Raman spectroscopy a temperature dependent study was carried out. Mean free paths due to plasmon-phonon scattering in nanotube bundles and electron-phonon scattering in debundled tubes are calculated and found to be different.
Gregan, E.:The Use of Raman Spectroscopy in the Characterization of Single Walled Carbon Nanotubes. Doctoral Thesis. Dublin Institute of Technology, 2009.