Nanomaterials Group, University of Southampton

Nanomaterials Group

Carbon Nanotube Raman

Single walled carbon nanotubes are effectively "drinking straws" where the walls of the "straw" are made from a single atomic layer of graphite. They have many exciting properties, e.g. they are the strongest "ropes" per unit mass ever discovered. Another key property is that electrons travelling along them can travel many microns before scattering, i.e. they are ballistic conductors, which opens up possible applications in quantum computing and other quantum systems.

There is a huge interest in carbon nanotubes around the world. Our research on these materials includes measuring the properties of their lattice vibrations, phonons, using time resolve incoherent Raman scattering. Raman scattering is the process by which a photon of light interacting with a material loses or gains energy creating or destroying an elementary excitation within the material. A Raman spectra for single walled carbon nanotubes is shown below with the number of scattered photons measured per sec plotted against the difference in energy between the incoming and scattered photons. A discussion of the various peaks (vibrational modes) can be found on the next page.