Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High-speed nanotube transistors could lead to better cell phones, faster computers

28.04.2004


Scientists have demonstrated, for the first time, that transistors made from single-walled carbon nanotubes can operate at extremely fast microwave frequencies, opening up the potential for better cell phones and much faster computers, perhaps as much as 1,000 times faster.



The findings, reported in the April issue of Nano Letters, a peer-reviewed journal of the American Chemical Society, the world’s largest scientific society, add to mounting enthusiasm about nanotechnology’s revolutionary potential.

"Since the invention of nanotube transistors, there have been theoretical predictions that they can operate very fast," says Peter Burke, Ph.D., a professor of electrical engineering and computer science at the University of California, Irvine, and lead author of the paper. "Our work is the first to show that single-walled nanotube transistor devices can indeed function at very high speeds."


Burke and his colleagues built an electrical circuit with a carbon nanotube between two gold electrodes. When they varied the voltage, the circuit operated at a frequency of 2.6 gigahertz (GHz), which means electrical current could be switched on and off in about one billionth of a second. This is the first demonstration of a nanotube operating in the frequency range of microwaves — electromagnetic waves with faster frequencies than radio waves.

Although Burke’s group demonstrated that nanotube transistors could work in the GHz range, he believes that much faster speeds are possible. "I estimate that the theoretical speed limit for these nanotube transistors should be terahertz [1 THz=1,000 GHz], which is about 1,000 times faster than modern computer speeds." His team is currently doing related research on the theoretical prediction of the cutoff frequency, or so-called speed limit, for these transistors.

Every transistor has a cutoff frequency, which is the maximum speed at which it can operate. For silicon, the cutoff is about 100 GHz, but current circuits typically operate at much slower speeds, according to Burke. For example, some of today’s newest processor chips still operate below 5 GHz.

Nanotechnology is the science of the very small: a nanometer is one billionth of a meter, or about 1,000 times smaller than the width of a human hair. A nanotube is another form of carbon, like graphite or diamond, where the atoms are arranged like a rolled-up tube of chicken wire.

Electrons move without losing energy inside nanotubes, which makes them perfect candidates for connections in electrical devices. A semiconducting carbon nanotube can act as a transistor — the key component in all modern electronics — because it can be switched on and off.

High-speed nanotube transistors could be useful in a number of applications. "Theoretically, this can translate into very low noise microwave amplifiers that could increase the range in which cell phones operate," Burke says. A cell phone receives its radio signal at a very low strength, so a microwave amplifier is needed to boost the signal for further processing.

Nanotube transistors could also lead to very high quality microwave filters that can separate out many different phone conversations more efficiently than current filters, and at lower cost, according to Burke. "Right now, this one function requires a separate chip inside a cell phone," he says. If the filter could be integrated with the other processing parts, the entire radio system would be on one chip, saving power, space and cost.

This type of "integrated nanosystem" is a goal of Burke’s research. "Ultimately, we would like more sophisticated circuits on a single chip," he says. "Our nanotube transistor is on a silicon substrate, but there are no active silicon devices." If all the transistors and electrical connections on a chip were made of nanotubes or nanowires, there would be no silicon parts to slow things down.

Burke expects to have a prototype transistor available within two years. "We still need to demonstrate operation at room temperature, which we are working on in my lab now. Also, we need to show that we can achieve amplification," he says. "But these are both achievable goals given one or two years of work."

The Army Research Office, the Office of Naval Research, and the Defense Advanced Research Projects Agency provided funding for this research.

Michael Bernstein | EurekAlert!
Further information:
http://www.acs.org/

More articles from Power and Electrical Engineering:

nachricht Producing electricity during flight
20.09.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Solar-to-fuel system recycles CO2 to make ethanol and ethylene
19.09.2017 | DOE/Lawrence Berkeley National Laboratory

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>