Swiss bring atomic realm into focus

Images of graphite from a pencil magnified by an electron microscope, demonstrates the size of nano-scale swissinfo.ch

Microscopes developed in Zurich more than 20 years ago have put Switzerland in the vanguard of the nanoscience revolution.

In 1981, scientists at IBM’s Zurich research laboratory invented the scanning tunnelling microscope, which allowed them to view individual molecules and atoms for the first time.

They were awarded a Nobel prize in physics for their efforts, which opened up new fields for the study of the structure of matter. Nanoscientists deal with objects which measure just a few nanometres (millionths of a millimetre) across.

Spine-tingling discovery

“When I saw the first atom appearing, it sent shivers down my spine,” said Christoph Gerber of IBM Zurich, whose collaboration with Gerd Binnig and Heinrich Rohrer, proved so successful. “It was incredible to see an atom in three dimensions for the first time.”

A 20-strong Swiss delegation of scientists and businesspeople toured the United States in May to showcase Switzerland’s expertise in nanotechnology.

Gerber said Switzerland has continued to maintain its competitive edge when it comes to producing instruments for the “nano-age”.

“We still have a great lead in the basic physics. Using this instrumentation in the institute of biochemistry at Basel university, it was possible to show for the first time how a cell membrane operates.

“You can literally see life, and that is a fascinating achievement. So in the application of this instrumentation, we still have a great advantage.”

New vision

The principle of the scanning tunnelling microscope (STM) differs completely from that of other microscopes.

To get an image, the STM uses a quantum mechanical effect called electron tunnelling. If a sharp tip is brought within one nanometre of a surface, a very small current flows between them.

By scanning the tip over the sample at a constant distance and recording its movements, researchers can draw an image of the surface on a computer screen. New variations of this device continue to be developed even today.

“It opened the nano world to visualisation,” said Gerber. “It gave the scientific community a much broader view of what is happening at the nanometre scale simply because you can see it. Not all scientists are like Albert Einstein who can picture things in an abstract way.”

Building an instrument of the precision and stability required was a laborious task. To eliminate disturbing vibrations from the environment, the team assembled the microscope on a heavy permanent magnet floating freely in a dish of superconducting lead.

Revolution in the making

The development of the scanning tunnelling microscope enabled scientists not only to view individual molecules and atoms but also to move them from place to place.

The ability to study the atomic structure of surfaces is an important part of physics with particular applications in semiconductor physics and microelectronics. In chemistry, surface reactions play an important role in processes like catalysis.

“What we’re doing at the moment is a worldwide effort to put the science of the nanoscale on a solid foundation and obviously it is inevitable that a new technology will emerge,” said Gerber.

“I’m still hesitant to use the word nanotechnology because it is nanoscience that we’re doing at the moment. Nanotechnology has been hyped up tremendously in the last few years by scientists and politicians and it could create a false image. There is no doubt that it will revolutionise the world but we are not there yet.”

by Vincent Landon