Nanoscale welding

Sheffield University researchers have developed nanowelding, an innovative technique that joins together nanoscale-objects.

Drs Yong Peng and Beverley Inkson, from the Department of Engineering Materials, developed the technique, which uses tiny blobs of metal solder less than 250 atoms across to weld individual nano-objects a thousand times smaller than a human hair.

Nanowelding is becoming important as a way to allow engineers to make nanoelectronic devices.

Most manufactured objects, from aeroplanes to electronic devices, require complex joining processes to link materials into a single working structure.

However, most everyday joining techniques cannot be applied at the nanoscale, as nano-objects are easily destroyed by heat.

The new technique works by heating a tiny metal wire which is in contact with the materials to be joined.

The solder wire melts and flows onto the join.

The welding can be watched in real-time inside an electron microscope, allowing the choice of exactly where, and how much, nanosolder is deposited.

Dr Inkson said: 'Previous research has concentrated on developing ways to make individual nanoscale objects, but not many ways to join them together.

‘Our new technique is particularly exciting because the chemistry, strength and conductivity of the join can be engineered at the nanoscale.'

The research has been published in the online journal Nano Letters.