Robin Nicholas

Abstract:

We have studied the mangeto-photoluminescence (PL) of single-walled carbon nanotubes (SWCNTs) with different chiral vector indices (n,m). A novel strain method is used to assign the quantum number q and chiral vector indices. The PL intensities and energies were found to be a strong function of magnetic field at low temperature, but were field independent up to 19.5T at 300K. All emission energies show a significant red shift caused by the action of Aharanov-Bohm flux threading the tubes.

Abstract:

The room temperature electroluminescence (EL) between 1.7-2.6 μ from coupled quantum dots and quantum wells in the InAs/InSb/GaSb materials system was investigated. The samples which were investigated consisted of a single narrow InAs quantum well grown below a layer of InSb quantum dots in a GaSb matrix. It was found that the thickness of the GaSb space layer lowers the energy from that of a quantum well alone. The results reveal the occurrence of a sharp transition after a single monolayer coverage of GaSb either due to structural changes in the quantum dots or from the shrinkage of the quantum well.

Abstract:

A clear understanding of the interactions between the building blocks of self-assembled molecular materials is essential for rational design of functional nanostructures. Intermolecular interactions have been investigated for three different classes of fullerenes in single-walled carbon nanotubes (SWNTs); van der Waals molecule -molecule and molecule-SWNT interactions control the geometry of the molecular arrays inside nanotubes; electrostatic intermolecular forces influence the alignment of polar endohedral fullerenes M@C-82; and hydrogen bonding between functionalised fullerenes has a significant effect on the selectivity of insertion of functionalised fullerenes into SWNTs.