Pen writes micro wires

Researchers from the Swiss Federal Institute of Technology and the University of California have devised a way to write stripes of gold onto glass to produce microscopic wires.

The researchers' prototype has produced continuous gold stripes as narrow as five microns wide and a few tenths of a micron high. A micron is one-thousandth of a millimeter.

The current prototype has the potential to write features on the order of a single micron wide, according to the researchers. A micron is about 75 times narrower than a human hair. This is about ten times narrower than microstructures produced using inkjet printing techniques, according to the researchers.

The method could eventually be used manufacture conductors for tiny electronics devices.

The method calls for using a micropipette to write liquid that contains suspended gold nanoparticles on glass, then using a laser to evaporate the liquid and sinter the nanoparticles together. The tricky part was working out the optimum laser intensity and focus, and the optimum scanning speed, according to the researchers.

The researchers are working on improving the system to write stripes as narrow as 100 nanometers, which is 750 times narrower than a human hair.

The method could be used practically in two to five years, according to the researchers. The work appeared in the July 5, 2004 issue of Applied Physics Letters.