(a) Confocal image of the G band integrated intensity ( eV, spatial resolution ~500 nm) for SWNT serpentine on () quartz. The spectral intensity is stronger in segments aligned along the steps because of the light polarization dependence for the Raman scattering [8]. (b) The G band at different points on the same serpentine shown in (a). An additional broad peak at the G band (~1540 cm−1) has been observed on the flat sections (spectra 1, 3, and 5), indicating a metallic character. This additional peak disappears in spectra 2 and 4, indicating a semiconducting character (adapted from [30]).
