An international group of researchers from the University of Minnesota, Argonne National Laboratory and Seoul National University have discovered a groundbreaking technique in manufacturing nanostructures that has the potential to make electrical and optical devices smaller and better than ever before. A surprising low-tech tool of Scotch Magic tape ended up being one of the keys to the discovery. The research is published today in Nature Communications, an international online research journal.

Combining several standard nanofabrication techniques -- with the final addition of the Scotch Magic tape -- researchers at the University of Minnesota created extremely thin gaps through a layer of metal and patterned these tiny gaps over the entire surface of a four-inch silicon wafer. The smallest gaps were only one nanometer wide, much smaller than most researchers have been able to achieve. In addition, the widths of the gaps could be controlled on the atomic level. This work provides the basis for producing new and better nanostructures that are at the core of advanced electronic and optical devices.

One of the potential uses of nanometer-scale gaps in metal layers is to squeeze light into spaces much smaller than is otherwise possible. Collaborators at Seoul National University, led by Prof. Dai-Sik Kim, and Argonne National Laboratory, led by Dr. Matthew Pelton, showed that light could readily be squeezed through these gaps, even though the gaps are hundreds or even thousands of times smaller than the wavelength of the light used. Researchers are very interested in forcing light into small spaces because this is a way of boosting the intensity of the light. The collaborators found that the intensity inside the gaps is increased by as much as 600 million times.

"Our technology, called atomic layer lithography, has the potential to create ultra-small sensors with increased sensitivity and also enable new and exciting experiments at the nanoscale like we've never been able to do before," said Sang-Hyun Oh, one of the lead researchers on the study and a professor of electrical and computer engineering in the University of Minnesota's College of Science and Engineering. "This research also provides the basis for future studies to improve electronic and photonic devices."