Credit: © 2007 IOP

There are several methods to cut and shape carbon nanotubes, but few are precise or can work effectively for all nanotube thicknesses. Now, Qing Chen and co-workers1 at Peking University in Beijing, China, have created a 'nanoknife' that can slice and sharpen nanotubes, both accurately and efficiently.

The 'blade' of the knife is a short carbon nanotube. When a sufficiently large voltage is applied across the nanotube blade, it becomes hot enough to melt and 'slice' through material with which it is in contact, such as another nanotube. When the blade is removed, it carries away a segment of the cut material that can be easily cleaned off before the blade is used again.

The blade can be used to sharpen multiwalled nanotubes by melting away the outer shells of their tips. In addition, Chen and co-workers are able to make complex interconnected structures by leaving cut segments along the edge of the blade — a technique that can be applied in nanoscale electrical circuits and ensures that nothing goes to waste.