Electron energy-loss spectroscopy on individual nanotubes

Different spatially resolved electron energy-loss spectroscopy (EELS) exper iments on individual nanotubes performed in the context of a scanning trans mission electron microscope (STEM) are presented. The capabilities of EELS for probing the local anisotropy of the unoccupied electronic states are de monstrated and the effects of the graphite network curvature on the nature of the chemical bonding is investigated. The peculiarity of the valence ele ctron excitation modes in carbon nanotubes due to the curved anisotropy is also pointed out through near-field EELS experiments. (C) 2001 Elsevier Sci ence B.V; All rights reserved.