A Resonant Raman Study of SWNTs under Electrochemical Doping

The first and second‐order high‐energy Raman modes of single‐walled carbon nanotubes were investigated as a function of electrochemical doping for excitation energies in the range 477 – 780 nm. In the metallic resonance window (560 – 740 nm) a new peak was detected in the HEM region and found to exhibit spectacular shifts upon doping. For excitation energies above and below the metallic resonance range this new peak is absent. The second‐order D mode also shifts with doping; the shift, however, strongly depends on excitation energy. In double resonance this corresponds to a wave‐vector dependence of the doping‐induced shift of the phonon branches.