Featured Research

from universities, journals, and other organizations

Newly Designed Carbon Tubes Could Replace Silicon In Microchips

Date:
August 29, 2001
Source:
American Chemical Society
Summary:
Researchers have created the first functional logic circuit within a single molecule, an achievement that could one day help to replace silicon in microchips. This is a significant step toward smaller, faster and less power-consuming computers, according to the researchers.

Researchers have created the first functional logic circuit within a single molecule, an achievement that could one day help to replace silicon in microchips. This is a significant step toward smaller, faster and less power-consuming computers, according to the researchers.

Related Articles


The finding will be published in the August 26 Web edition of Nano Letters, a peer-reviewed journal of the American Chemical Society, the world’s largest scientific society. The researchers also will present their findings August 26 at the Society’s 222nd national meeting in Chicago.

“We believe that carbon nanotubes are now the top candidate to replace silicon when current chip features just can’t be made any smaller, a physical barrier expected to occur in about 10 to 15 years,” said Phaedon Avouris, manager of Nanometer Scale Science and Technology at the IBM T.J. Watson Research Center in Yorktown Heights, N.Y.

The new circuit works on a miniature scale, using a hollow carbon tube approximately 1.4 nanometers in diameter, or approximately 100,000 times thinner than a human hair. The researchers changed the nanotube’s electrical characteristics so that some sections would allow the flow of electrons (called n-type, or negative, sections), while other sections would allow the flow of electric current using positive entities on the nanotube called positive holes (also known as p-type, or positive, sections).

The sections were turned into transistors that encode the “NOT” logic function along the length of the nanotube, Avouris said. The characteristics of the resulting circuit — its ability to propagate voltage, called gain — allows for more transistors to be placed along the tube to make more complex circuits. Both p- and n-type sections are needed to build a logic circuit.

While working with their previously assembled p-type transistors, the IBM team discovered a very simple way of producing n-type transistors: simply heating a p-type transistor in a vacuum, Avouris said. In the future, the researchers plan to create more complex circuits and to further improve the performance of the individual transistors, he added.

All information stored in a computer is made up of two digits — ones and zeros — which indicate, for example, whether a circuit is on (one) or off (zero). The circuit described in the research can switch the ones to zeros, and vice versa, according to Avouris. Changing from a one to a zero directs the computer to perform separate functions, telling it essentially to do one thing, not another.

The circuit, therefore, is called a “NOT gate” in computer parlance, one of two fundamental combinatorial logic circuits that computers use to perform computations. Also known as a voltage inverter, the gate sends out the opposite voltage from the one it receives. Other logic circuits include the “AND” and “OR” gates, which perform other computations. The “NOT” gate, in combination with either the “AND” or the “OR” gates, can form all other logic circuits. All these functions are currently accomplished using silicon chips in modern computers.

The research would help maintain Moore’s Law, a prediction that suggested computers typically double their capacity and number of circuits every two years. Computers will eventually reach a maximum capacity with silicon that cannot be overcome, forcing the need for new materials capable of adding smaller computer circuits to maintain the advancements in the future, Avouris said.


Story Source:

The above story is based on materials provided by American Chemical Society. Note: Materials may be edited for content and length.


Cite This Page:

American Chemical Society. "Newly Designed Carbon Tubes Could Replace Silicon In Microchips." ScienceDaily. ScienceDaily, 29 August 2001. <www.sciencedaily.com/releases/2001/08/010829083422.htm>.
American Chemical Society. (2001, August 29). Newly Designed Carbon Tubes Could Replace Silicon In Microchips. ScienceDaily. Retrieved November 29, 2014 from www.sciencedaily.com/releases/2001/08/010829083422.htm
American Chemical Society. "Newly Designed Carbon Tubes Could Replace Silicon In Microchips." ScienceDaily. www.sciencedaily.com/releases/2001/08/010829083422.htm (accessed November 29, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Saturday, November 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Magnetic Motors, Not Cables, Power This Elevator

Magnetic Motors, Not Cables, Power This Elevator

Newsy (Nov. 28, 2014) Imagine an elevator without cables. ThyssenKrupp has drafted an elevator concept that would cruise on linear magnetic motors. Video provided by Newsy
Powered by NewsLook.com
NASA's First 3-D Printer In Space Creates Its First Object

NASA's First 3-D Printer In Space Creates Its First Object

Newsy (Nov. 26, 2014) The International Space Station is now using a proof-of-concept 3D printer to test additive printing in a weightless, isolated environment. Video provided by Newsy
Powered by NewsLook.com
Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Bolivian Recycling Initiative Turns Plastic Waste Into School Furniture

Reuters - Innovations Video Online (Nov. 26, 2014) Innovative recycling project in La Paz separates city waste and converts plastic garbage into school furniture made from 'plastiwood'. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Blu-Ray Discs Getting Second Run As Solar Panels

Blu-Ray Discs Getting Second Run As Solar Panels

Newsy (Nov. 26, 2014) Researchers at Northwestern University are repurposing Blu-ray movies for better solar panel technology thanks to the discs' internal structures. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins