Carbon nanotubes represent an important model system in nanoscience and nanotechnology. The tubes are essentially one-dimensional, typically 1-2 nm in diameter and up to 1 mm long and combine nanoscale and macroscopic physics. Besides their extreme mechanical and thermal properties, the electronic conductance can vary from insulating to metallic depending on the tube chirality or helicity. Despite the large amount of research carried out on nanotubes, there are several key aspects of the electronic and optical properties that are poorly understood. These include the sensitivity of nanotubes to their local environment such as their light emitting and absorption properties. There is a large discrepancy between theoretical models and the observed emission spectra. Most current emission data comes from ensemble measurements of tubes surrounded by a surfactant, suspended in a solution. We present resonant inelastic light scattering (Raman) studies of individual tubes suspended in air. These results differ significantly from earlier measurements from tubes in solution. The energy down-shift and resonance profile indicate exciton than rather band edge optical excitations. Individual and suspended tubes are mapped spatially. We will discuss the experimental results with respect to results obtained from solution measurements.
Journal: TechConnect Briefs
Volume: 2, Technical Proceedings of the 2005 NSTI Nanotechnology Conference and Trade Show, Volume 2
Published: May 8, 2005
Pages: 155 - 158
Industry sector: Advanced Materials & Manufacturing
Topic: Carbon Nano Structures & Devices