It was shown that the location of chemical defects in single-walled carbon nanotubes could be easily identified. The method relied upon the formation of Se nanoparticles via site-selective oxidation of H2Se, which worked under soft conditions at room temperature and was able to reveal the defects; even in individual tubes.

Chemical Defect Decoration of Carbon Nanotubes. Y.Fan, M.Burghard, K.Kern: Advanced Materials, 2002, 14[2], 130-3