The Optical Resonances in Carbon Nanotubes Arise from Excitons

✍ Scribed by Wang, F.

• Book ID: 111929878
• Publisher: American Association for the Advancement of Science
• Year: 2005
• Tongue: English
• Weight: 266 KB
• Volume: 308
• Category: Article
• ISSN: 0036-8075
• DOI: 10.1126/science.1110265

✦ Synopsis

Optical transitions in carbon nanotubes are of central importance for nanotube characterization. They also provide insight into the nature of excited states in these one-dimensional systems. Recent work suggests that light absorption produces strongly correlated electron-hole states in the form of excitons. However, it has been difficult to rule out a simpler model in which resonances arise from the van Hove singularities associated with the one-dimensional bond structure of the nanotubes. Here, two-photon excitation spectroscopy bolsters the exciton picture. We found binding energies of ∼400 millielectron volts for semiconducting single-walled nanotubes with 0.8-nanometer diameters. The results demonstrate the dominant role of many-body interactions in the excited-state properties of one-dimensional systems.