Creating complex 3D metallic structures at nanoscale

October 21, 2012

Microparticles of lactose are trapped in self-organized structures made from thin-film metal. (credit: Khattiya Chalapat, et al./Aalto University)

Scientists from Aalto University in Finland and the University of Washington have demonstrated how to create complex 3D structures at nanoscale by combining ion processing and nanolithography.

The fabrication of many objects, machines, and devices rely on the controlled deformation of metals by industrial processes such as bending, shearing, and stamping. Is this technology transferrable to nanoscale? Can we build similarly complex devices and machines with very small dimensions?

When dandelion flowers bloom, if you cut the flower stem into small strips and put them in water, the strips will fold with observable width-dependent curvatures due to differences in the water absorption between the inside and outside parts of the stem.

“Our idea was to find a way to adapt these natural processes to nanofabrication,” said Khattiya Chalapat of Aalto University. “This led us to an incidental finding that a focused ion beam can locally induce bending with nanoscale resolution.

Folding of metal thin films by reactive ion etching  (credit: Khattiya Chalapat, et al./Aalto University)

“The technology has applications in the fabrication of nanoscale devices. The structures are surprisingly resilient:­ the team found them to be quite sturdy and robust under a variety of adverse conditions, such as electrostatic discharge and heating.

Because the structures are so small, the coupling and the magnitude of typical nanoscale forces acting on them would be commensurately small.

“We have demonstrated so far that these structures can capture and retain particles with dimensions of the order of a micrometer,” said Sorin Paraoanu of Aalto University.