Oxidation and opening of well-aligned carbon nanotube tips

We report here that well-aligned carbon nanotubes with open tips can be directly obtained by introducing carbon dioxide during the chemical vapor deposition process. In-situ oxidation of carbon nanotubes by carbon dioxide results in the strip off of nanotube tips, however, without damaging the nanotube alignment. Such oxidation of aligned nanotube arrays, whose tips are all on the array surface, is more efficient than the oxidation of disordered nanotubes. Aligned carbon nanotube arrays with open tips have potential applications in field emission, filter membrane, and energy storage.