Boron–carbon nanotubes from the pyrolysis of <font>C</font>₂ <font>H</font>₂–<font>B</font>₂ <font>H</font>₆ mixtures

Boron-doped carbon nanotubes have been prepared by the pyrolysis of acetylene-diborane mixtures in a stream of helium and hydrogen. The nanotubes so obtained have compositions around C35B. The presence of boron favours nanotube formation and the boron content does not vary with the depth. Considering that the nitrogen-doped nanotubes, reported recently (Chem. Phys. Lett. 287 (1997) 671) have the average composition C35N, it may be possible to use a combination of these p-type and n-type nanotubes for certain applications. (C) 1999 Elsevier Science B.V. All rights reserved.