In situ raman measurements of suspended individual single-walled carbon nanotubes under strain

We present a technique for in situ Raman measurements of suspended individual single-walled carbon nanotubes (SWNTs) under strain. We observe a strong change in the radial breathing mode intensity with increasing strain as the nanotube moves out of (or into) resonance, and for strain greater than ∼2%, there is a clear irreversible upshift in the G-mode frequencies accompanied by an increase in intensity of a broad peak at a position associated with the D mode. For lower strain, the G-mode peaks (A₁, E ₁, and E₂) do not change significantly in position but change in relative intensity.