Jet-laser tandem prints gold

Researchers from the Swiss Federal Institute of Technology (ETH) and the University of California at Berkeley have found a way to print gold structures.

The researchers suspended gold nanoparticles, which have a lower melting point then bulk gold, in a solution and used a modified ink-jet printer to print patterns of the solution onto a surface. At the same time, they melted the gold and evaporated the solvent with a laser whose wavelength matched the absorption properties of gold and was precisely focused on the metal.

The researchers' prototype produced gold lines that measured 10 to several hundred microns across and 20 to 200 nanometers thick. A human hair, in contrast, is about 75 microns in diameter.

The method could also be used with other materials to print microelectronics devices like resistors, capacitors and interconnections using relatively low temperatures, according to the researchers.

They are working on integrating a CAD program into the system to control the gold-printing process, and are studying the quality and durability of the printed structures.

The method could be used in practical applications within two years, according to the researchers. The work appeared in the May 19, 2003 issue of Applied Physics Letters.