Chiral structure determination of aligned single-walled carbon nanotubes on graphite surface

Chiral structure determination of single-walled carbon nanotube (SWNT), including its handedness and chiral index (n,m), has been regarded as an intractable issue for both fundamental research and practical application. For a given SWNT, the n and m values can be conveniently deduced if an arbitrary two of its three crucial structural parameters, that is, diameter d, chiral angle θ, and electron transition energy E_ii, are obtained. Here, we have demonstrated a novel approach to derive the (n,m) indices from the θ, d, and E_ii of SWNTs. Handedness and θ were quickly measured based on the chirality-dependent alignment of SWNTs on graphite surface. By combining their measured d and E_ii, (n,m) indices of SWNTs can be independently and uniquely identified from the (θ,d) or (θ,E _ii) plots, respectively. This approach offers intense practical merits of high-efficiency, low-cost, and simplicity.