Featured Research

from universities, journals, and other organizations

Switching To Chemistry

Date:
April 22, 2005
Source:
Weizmann Institute
Summary:
Researchers at the Weizmann Institute of Science have demonstrated a new kind of electrical switch, formed of organic molecules, that could be used in the future in nanoscale electronic components.

Researchers at the Weizmann Institute of Science have demonstrated a new kind of electrical switch, formed of organic molecules, that could be used in the future in nanoscale electronic components.

Their approach involved rethinking a phenomenon that drives many of today's high-speed semiconductors. Negative differential resistance (NDR), as the phenomenon is called, works contrary to the normal laws of electricity, in which an increase in voltage translates into a direct increase in current. In NDR, as the voltage steadily increases, the current peaks and then drops off, essentially allowing one to create a switch with no moving parts. But until now, those attempting to recreate NDR at the molecular scale had only managed it at extremely low temperatures.

Prof. David Cahen of the Institute's Materials and Interfaces Department and graduate student Adi Salomon thought research carried out by Salomon and others in Cahen's lab during her M.Sc. studies on connections between metal wires and organic (carbon based) molecules might hold part of the key to usable nanoscale NDR. They had found that, like people, molecules and metal wires need chemistry between them for barriers to be lowered and the juice to really flow. For a given voltage, if the molecules are held to the wire by chemical bonds (in which the two are linked by shared electrons), the current flowing through them will be many times higher than if they are only touching a mere physical bond.

Using this insight, the team designed organic molecules that pass electricity through chemical bonds at a lower voltage, but through physical bonds at a higher voltage. As the voltage approaches the higher level, sulfur atoms at one end of the molecule loosen their chemical bonds with the wire, and the current drops off as the switchover occurs.

But the molecules, once the chemical bond to the wire was broken, tended to move apart, preventing them from switching back to the chemically-bonded state. Prof. Abraham Shanzer of the Organic Chemistry Department, who had worked with the team on the original molecular design, now helped them to create long add-on tails to hold the molecules in place with a weak attraction. Now, the NDR in their molecules was stable, reversible and reproducible at room temperature.

Possible applications include nanoscale electronic memory and heat-sensing switches. The future of miniaturized electronics may lie in methods that combine chemistry with nanoscience, say the scientists. "We don't take human-sized objects and try to scale them down, but create new things from the universe of possibilities open to chemists that are specifically designed to function in the nanoworld."

Prof. David Cahen's research is supported by the Minerva Stiftung Gesellschaft fuer die Forschun M. B. H.; the Wolfson Advanced Research Center; the Philip M. Klutznick Fund for Research; Delores and Eugene M. Zemsky; and the Weizmann-Johns Hopkins Research Program. Prof. Cahen is the incumbent of the Rowland Schaefer Professorial Chair in Energy Research.

###


Story Source:

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


Cite This Page:

Weizmann Institute. "Switching To Chemistry." ScienceDaily. ScienceDaily, 22 April 2005. <www.sciencedaily.com/releases/2005/04/050422000658.htm>.
Weizmann Institute. (2005, April 22). Switching To Chemistry. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/2005/04/050422000658.htm
Weizmann Institute. "Switching To Chemistry." ScienceDaily. www.sciencedaily.com/releases/2005/04/050422000658.htm (accessed August 23, 2014).

Share This




More Matter & Energy News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Is It a Plane? No, It's a Hoverbike

Is It a Plane? No, It's a Hoverbike

Reuters - Business Video Online (Aug. 22, 2014) UK-based Malloy Aeronautics is preparing to test a manned quadcopter capable of out-manouvering a helicopter and presenting a new paradigm for aerial vehicles. A 1/3-sized scale model is already gaining popularity with drone enthusiasts around the world, with the full-sized manned model expected to take flight in the near future. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Coal Gas Boom in China Holds Climate Risks

Coal Gas Boom in China Holds Climate Risks

AP (Aug. 22, 2014) China's energy revolution could do more harm than good for the environment, despite the country's commitment to reducing pollution and curbing its carbon emissions. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Former TSA X-Ray Scanners Easily Tricked To Miss Weapons

Former TSA X-Ray Scanners Easily Tricked To Miss Weapons

Newsy (Aug. 21, 2014) Researchers found the scanners could be duped simply by placing a weapon off to the side of the body or encasing it under a plastic shield. Video provided by Newsy
Powered by NewsLook.com
Flower Power! Dandelions Make Car Tires?

Flower Power! Dandelions Make Car Tires?

Reuters - Business Video Online (Aug. 20, 2014) Forget rolling on rubber, could car drivers soon be traveling on tires made from dandelions? Teams of scientists are racing to breed a type of the yellow flower whose taproot has a milky fluid with tire-grade rubber particles in it. As Joanna Partridge reports, global tire makers are investing millions in research into a new tire source. Video provided by Reuters
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:
from the past week

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