Tip-enhanced Raman investigation of extremely localized semiconductor-to-metal transition of a carbon nanotube.

The electronic properties of single walled carbon nanotubes (SWNTs) can change with a slight deformation, such as the one caused by the pressure of one SWNT crossing over the other in an "X" shape. The effect, however, is extremely localized. We present a tip-enhanced Raman investigation of the extremely localized semiconductor-to-metal transition of SWNTs in such a situation, where we can see how the Fano interaction, which is a Raman signature of metallic behavior, grows towards the junction and is localized within a few nanometers of its vicinity. After exploring the deconvoluted components of the G-band Raman mode, we were able to reveal the change in electronic properties of a SWNT at extremely high spatial resolution along its length.