Physicists use electron beam to carve worlds tiniest metal nanostructures

Physicists at the University of Pennsylvania are using a new technique to craft the world tiniest metal nanostructure: no larger than 10 nanometers, or 10,000 times smaller than the width of a single human hair.

Washington, June 26 : Physicists at the University of Pennsylvania are using a new technique to craft the world tiniest metal nanostructure: no larger than 10 nanometers, or 10,000 times smaller than the width of a single human hair.

The technique employs transmission electron beam ablation lithography, or TEBAL, to "carve" nanostructures from thin sheets of gold, silver, aluminium and other metals.

Scientists say TEBAL provides a more dependable method for producing quality versions of these microscopic devices. The method also permits simultaneous, real-time atomic imaging of the devices as they are made.

On the other hand, traditional techniques for building nanodevices, while also employing electron beam lithography, further require the use of polymers and chemicals in which the metal is evaporated.

Typical results are closer to 50 nanometers in size and rarely as small as 10.

Using the new technique, Marija Drndie, professor of physics at Penn, and her team, have now created nanodisks, nanorings, nanowires, nanoholes and multi-terminal nano-transistors.

The team used the superior control of the electron beam to reproduce multiple, identical copies of each structure.

"Many different approaches have been undertaken to fabricate the small structures needed to probe the phenomena that take place at the nanoscale, but the most widely used and versatile techniques are limited to tens of nanometers," said Prof. Drndie.

"Reliably and consistently fabricating devices at the sub-10-nanometer scale from the top down is generally still challenging, but our technique offers a route to this regime," she said.

Prof. Drndie said the TEBAL method also created a resistance-free connection between the nanostructure and an electrical lead that might provide power to the device.

The more parts involved, the greater the chance of a drop in electrical conduction between parts. Plus, structures made from bottom-up techniques, that is, assembled from smaller components, typically first need to be placed on a chip and then connected to larger circuitry, she said.

Working with a single piece of metal means there are no additional parts to reduce efficiency, she added.

The results were published in the journal Nano Letters.

ANI