Raman scattering study on fullerene derived intermediates formed within single-wall carbon nanotube: from peapod to double-wall carbon nanotube

By heating of C60 peapods at 900 °C in vacuum, eight or more Raman peaks associated with the inner tubes were observed in the frequency range of the radial breathing mode vibration. An analysis of time traces of the peak intensities led to the growing mechanism of double-wall nanotubes: inner tubes with ≈0.7 nm diameters are first formed and then increase their diameters. To explain these phenomena, we propose a model based on formation of short achiral zig-zag nanotubes in the beginning of C60 coalescence.