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In this work, an atomic force microscope (AFM) is combined with a confocal Raman spectroscopy setup to follow in situ the evolution of the G-band feature of isolated single-wall carbon nanotubes (SWNTs) under transverse deformation. The SWNTs are pressed by a gold AFM tip against the substrate where they are sitting. From eight deformed SWNTs, five exhibit an overall decrease in the Raman signal intensity, while three exhibit vibrational changes related to the circumferential symmetry breaking. Our results reveal chirality dependent effects, which are averaged out in SWNT bundle measurements, including a previously elusive mode symmetry breaking that is here explored using molecular dynamics calculations.

The electromechanical behavior of single-walled carbon nanotubes (SWNTs) in contact with different materials is investigated by scanning probe microscopy. An anomalous diamond/semiconducting nanotube behavior is observed, which is consistent with ab initio calculations: the formation of a broken-gap heterojunction between semiconducting SWNTs and a hydrogenated diamond surface results in a metallic response for such SWNTs.

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