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 Generating needs-led electricity with biogas plants
17.10.2018 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

nachricht Ultra-light gloves let users 'touch' virtual objects
16.10.2018 | Ecole Polytechnique Fédérale de Lausanne

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: Goodbye, silicon? On the way to new electronic materials with metal-organic networks

Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.

Silicon, a so called semiconductor, is currently widely employed for the development of components such as solar cells, LEDs or computer chips. High purity...

Im Focus: Storage & Transport of highly volatile Gases made safer & cheaper by the use of “Kinetic Trapping"

Augsburg chemists present a new technology for compressing, storing and transporting highly volatile gases in porous frameworks/New prospects for gas-powered vehicles

Storage of highly volatile gases has always been a major technological challenge, not least for use in the automotive sector, for, for example, methane or...

Im Focus: Disrupting crystalline order to restore superfluidity

When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.

We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...

Im Focus: Micro energy harvesters for the Internet of Things

Fraunhofer IWS Dresden scientists print electronic layers with polymer ink

Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...

Im Focus: Dynamik einzelner Proteine

Neue Messmethode erlaubt es Forschenden, die Bewegung von Molekülen lange und genau zu verfolgen

Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Conference to pave the way for new therapies

17.10.2018 | Event News

Berlin5GWeek: Private industrial networks and temporary 5G connectivity islands

16.10.2018 | Event News

5th International Conference on Cellular Materials (CellMAT), Scientific Programme online

02.10.2018 | Event News

 
Latest News

Robot-assisted sensor system for quality assurance of press-hardened components

17.10.2018 | Trade Fair News

Sensory Perception Is Not a One-Way Street

17.10.2018 | Life Sciences

Plant Hormone Makes Space Farming a Possibility

17.10.2018 | Agricultural and Forestry Science

VideoLinks
Science & Research
Overview of more VideoLinks >>>