Measuring the uniaxial strain of individual single-wall carbon nanotubes: Resonance Raman spectra of atomic-force-microscope modified single-wall nanotubes

The use of resonant Raman spectroscopy of individual single-wall nanotubes (SWNT) to measure the phonon frequencies at various degrees of strain was discussed. It was shown by the spatially resolved Raman spectra that the strain extends over the length of the nanotube despite the van der Waals binding which tends to hold the nanotubes in place on the substrate. It was observed that the Raman intensity was not sensitive to strain, indicating that the strain-induced shift of the transition energies do not exceed the resonance window. The micro-Raman spectroscopy was found to be insensitive to the strain-induced defects.