This thesis reports the study of electronic structures for single-walled carbon nanotubes, single layer graphene and thin graphite. A brief introduction is given in Chapter 1 for the geometric and electronic structures of the materials studied while a review for the theory and experimental results relevant to this thesis is given in Chapter 2. The effects of hydrostatic pressure on surfactant-wrapped-single walled carbon nanotubes are studied in Chapter 3 by using photoluminscence and photoluminscence excitation mapping. It is found that the changes to the optical properties can be explained by the compression in carbon-carbon bonds, an effective uniaxial strain exerted on the nanotubes and changes in the surrounding environment leading to changes in the many-body interactions experienced by the nanotubes. Chapter 4 reports the study of cross-polarized photoluminescence of nanotubes isolated by conjugated polymers dispersed in solvents. The effects of Coulomb interactions on the optical bandgaps of the nanotubes are discussed here. Chapter 5 reports Cyclotron resonances studies of graphene monolayers. It is found that a significant asymmetry exists between the electron and hole band structures near the Dirac point, and the asymmetry is bigger than that is expected in a simple tight-binding model. Chapter 6 reports a magnetoabsorption study of the electronic structures near the K- and H- points. It is found that the transitions are not describe well by the conventional Slonczewski-Weiss-McClure model, but can be described instead with a simplified asymmetric effective bilayer model.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:525270 |
| Date | January 2009 |
| Creators | Chuang, Kai-Chieh |
| Contributors | Nicholas, Robin J. |
| Publisher | University of Oxford |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://ora.ox.ac.uk/objects/uuid:590ccfa7-2737-40c4-9a9c-ddb1b710cfef |
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