Photoelectronic transport imaging of individual semiconducting carbon nanotubes

Photoconductivity in individual semiconducting single-wall carbon nanotubes was investigated, using a confocal scanning optical microscope. The magnitude of the photocurrent was found to increase linearly with the laser intensity, and,to be maximum for parallel orientation between the light polarization and the tube axis. Larger currents were obtained upon illuminating the tubes at 514.5 nm in comparison:to those at 647.1 nm, consistent with the semiconducting tubes having a resonant absorption energy at the former wavelength. Moreover, the determination of the photoresponse as a function of position along single nanotubes has proven to be a useful tool to monitor local electronic structure effects. (C) 2004 American Institute of Physics.