Structural (n,m) Determination of Isolated Single-Wall Carbon Nanotubes by Resonant Raman Scattering

We show that the Raman scattering technique can give complete structural information for one-dimensional systems, such as carbon nanotubes. Resonant confocal micro-Raman spectroscopy of an $(n,m)$ individual single-wall nanotube makes it possible to assign its chirality uniquely by measuring one radial breathing mode frequency ωRBM and using the theory of resonant transitions. A unique chirality assignment can be made for both metallic and semiconducting nanotubes of diameter dₜ, using the parameters γ₀0ex0ex=0ex0ex2.9eV and ωRBM0ex0ex=0ex0ex248/dₜ. For example, the strong RBM intensity observed at 156cm^-1 for 785 nm laser excitation is assigned to the $(13,10)$ metallic chiral nanotube on a Si/SiO₂ surface.