Simple catalyst for the growth of small-diameter carbon nanotubes

We describe a simple technique to grow small (approximately 1–4 nm) diam carbon nanotubes both in and out of the plane of a silicon substrate using the decomposition of ethylene and a nickel–iron thin film catalyst. This procedure can be used to produce nanotubes for ultrasharp atomic force microscope probes as well as for nanotube-based electronic devices. The technique is compatible with the patterned growth of nanotubes and with standard device microfabrication processes.