Nano Electronics Researcher Decodes Radio Signals Using Atom-Sized Component

By Alexis Madrigal

An electron microscope image of a carbon nanotube with electrodes from
an earlier Peter Burke nanotube radio experiment.

Image: American Chemical Society

A
scientist has unveiled a working radio built from carbon nanotubes that
are only a few atoms across, or almost 1,000 times smaller than today’s
radio technology.

The nanotech device is a demodulator, a simple circuit that decodes
radio waves and turns them into audio signals. By hooking the decoder
up to two metal wires, University of California at Irvine professor
Peter Burke transmitted music via AM radio waves from an iPod to
speakers across the room.

“People have been working on nanoelectronics for many years, and there
have been advances at the device level on switches and wires,” said Burke, who reported his findings in the November 14 issue of the American Chemical Society’s Nano Letters. “This work takes a step towards showing nanoelectronics in systems.”

The process centers on working with tiny tubes of carbon only
discovered in the 1980s. They are sometimes called buckytubes, after
the noted inventor Buckminster Fuller.

Nanoelectronic systems are considered crucial to the continued
miniaturization of electronic devices. Many companies are interested in the
long-term potential of the technology. Nanomix has received over $15 million in
venture capital to commercialize various nanoelectronic devices from Okapi Venture Capital. The company
intends to commercialize carbon nanotubes that will work with standard
semiconductor technologies.

Burke’s system is not wholly constructed of nanomaterials. Aside from
the demodulator, the rest of the radio setup was off-the-shelf. But the
nanocomponent is a crucial step in developing a fully nano-sized radio.

“Though we have only demonstrated the critical component of the entire
radio system out of a nanotube (the demodulator), it is conceivable in
the future that all components could be nanoscale, thus allowing a
truly nanoscale wireless communications system,” Burke wrote in the
paper.

François Baneyx, director of the Center for Nanotechnology at the
University of Washington, said nanotubes have attracted a lot of
attention because of unique electrical properties that arise at the
atomic scale.

“They can behave as a semiconductor or metallic system and they have a
very high physical strength,” he said. “Researchers are actively
working on a large number of nanotechnology applications. In
nanoelectronics the focus is on the unique properties that arise at the
nanoscale. They are looking to
take advantage of the electronic properties of the nanotubes.”

While the potential for nanoelectronics is big, major manufacturing
problems remain. When scientists are working at the atomic scale,
imperfections of a couple of atoms have drastic repercussions.

“If one atom is out of place in a regular transistor, it’s not a big
deal,” Burke said. “If one atom is out of place in the nanotube, it has
a big impact on the electronic properties.”

That impact means that it is nearly impossible to make identical
components time and again, an obvious necessity for commercial
production.

“The cost and manufacturability are the big unsolved issues in nanotechnology,” Burke said.

Burke’s team is also looking at the interfaces between biological
systems and nanotechnologies. He sees opportunities in manipulating
human proteins, since they are about the same size as the
nanoelectronics.

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