Grapevine-like growth of single walled carbon nanotubes among vertically aligned multiwalled nanotube arrays

Large arrays of self-oriented, multiwalled carbon nanotubes (MWNTs) have been obtained by chemical vapor deposition. It has so far been impossible to translate this idea for growing single walled nanotubes (SWNTs) but we show here that oriented growth of SWNTs among vertically aligned MWNT arrays can be realized by the catalytic pyrolysis of ferrocene and xylene. The MWNTs act as the support structures for SWNTs, forcing them to grow upward steadily, like grapevines. The growth of vertically aligned SWNT over large areas brings about the possibility of exploring their properties in select configurations.