Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > UK nanodevice builds electricity from tiny pieces: Scientists from the UK's National Physical Laboratory have developed a nano-device which could change the way we define electrical current

Abstract:
A team of scientists at the National Physical Laboratory (NPL) and University of Cambridge has made a significant advance in using nano-devices to create accurate electrical currents. Electrical current is composed of billions and billions of tiny particles called electrons. NPL scientists have developed an electron pump - a nano-device - which picks these electrons up one at a time and moves them across a barrier, creating a very well-defined electrical current.

UK nanodevice builds electricity from tiny pieces: Scientists from the UK's National Physical Laboratory have developed a nano-device which could change the way we define electrical current

Cambridge, UK | Posted on July 11th, 2012

The device drives electrical current by manipulating individual electrons, one-by-one at very high speed. This technique could replace the traditional definition of electrical current, the ampere, which relies on measurements of mechanical forces on current-carrying wires.

The key breakthrough came when scientists experimented with the exact shape of the voltage pulses that control the trapping and ejection of electrons. By changing the voltage slowly while trapping electrons, and then much more rapidly when ejecting them, it was possible to massively speed up the overall rate of pumping without compromising the accuracy.

By employing this technique, the team were able to pump almost a billion electrons per second, 300 times faster than the previous record for an accurate electron pump set at the National Institute of Standards and Technology (NIST) in the USA in 1996.

Although the resulting current of 150 picoamperes is small (ten billion times smaller than the current used when boiling a kettle), the team were able to measure the current with an accuracy of one part-per-million, confirming that the electron pump was accurate at this level. This result is a milestone in the precise, fast, manipulation of single electrons and an important step towards a re-definition of the unit ampere.

As reported in Nature Communications, the team used a nano-scale semiconductor device called a 'quantum dot' to pump electrons through a circuit. The quantum dot is a tiny electrostatic trap less than 0.0001 mm wide. The shape of the quantum dot is controlled by voltages applied to nearby electrodes.

The dot can be filled with electrons and then raised in energy. By a process known as 'back-tunneling', all but one of the electrons fall out of the quantum dot back into the source lead. Ideally, just one electron remains trapped in the dot, which is ejected into the output lead by tilting the trap. When this is repeated rapidly this gives a current determined solely by the repetition rate and the charge on each electron - a universal constant of nature and the same for all electrons.

The research makes significant steps towards redefining the ampere by developing the application of an electron pump which improves accuracy rates in primary electrical measurement.

Supporting quotes:

Masaya Kataoka of the Quantum Detection Group at NPL said.

"Our device is like a water pump in that it produces a flow by a cyclical action. The tricky part is making sure that exactly the same number of electronic charge is transported in each cycle."

"The way that the electrons in our device behave is quite similar to water; if you try and scoop up a fixed volume of water, say in a cup or spoon, you have to move slowly otherwise you'll spill some. This is exactly what used to happen to our electrons if we went too fast."

Stephen Giblin part of the Quantum Detection Group at NPL said:

"For the last few years, we have worked on optimising the design of our device, but we made a huge leap forward when we fine-tuned the timing sequence. We've basically smashed the record for the largest accurate single-electron current by a factor of 300.

Although moving electrons one at a time is not new, we can do it much faster, and with very high reliability - a billion electrons per second, with an accuracy of less than one error in a million operations.

Using mechanical forces to define the ampere has made a lot of sense for the last 60 or so years, but now that we have the nanotechnology to control single electrons we can move on."

The technology might seem more complicated, but actually a quantum system of measurement is more elegant, because you are basing your system on fundamental constants of nature, rather than things which we know aren't really constant, like the mass of the standard kilogram."

####

For more information, please click here

Contacts:
Natasha Warren

084-568-01869

Copyright © National Physical Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

The full paper, published in Nature Communications, can be found here:

Related News Press

News and information

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

Iranians Present Model to Predict Photocatalytic Process in Removal of Pollutants October 30th, 2014

Production of Biocompatible Polymers in Iran October 30th, 2014

Physics

Sussex physicists find simple solution for quantum technology challenge October 28th, 2014

New evidence for an exotic, predicted superconducting state October 27th, 2014

Solid nanoparticles can deform like a liquid: Unexpected finding shows tiny particles keep their internal crystal structure while flexing like droplets October 12th, 2014

Unconventional photoconduction in an atomically thin semiconductor: New mechanism of photoconduction could lead to next-generation excitonic devices October 9th, 2014

Govt.-Legislation/Regulation/Funding/Policy

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

'Electronic skin' could improve early breast cancer detection October 29th, 2014

New solar power material converts 90 percent of captured light into heat: SunShot Project aims to make solar cost competitive October 29th, 2014

Tiny carbon nanotube pores make big impact October 29th, 2014

Discoveries

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

Iranians Present Model to Predict Photocatalytic Process in Removal of Pollutants October 30th, 2014

Production of Biocompatible Polymers in Iran October 30th, 2014

Announcements

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

Iranians Present Model to Predict Photocatalytic Process in Removal of Pollutants October 30th, 2014

Production of Biocompatible Polymers in Iran October 30th, 2014

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

Super stable garnet ceramics may be ideal for high-energy lithium batteries October 21st, 2014

Graphenea opens US branch October 16th, 2014

NTU develops ultra-fast charging batteries that last 20 years October 14th, 2014

Electrically conductive plastics promising for batteries, solar cells October 10th, 2014

Research partnerships

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

Sussex physicists find simple solution for quantum technology challenge October 28th, 2014

Molecular beacons shine light on how cells 'crawl' October 27th, 2014

New evidence for an exotic, predicted superconducting state October 27th, 2014

Quantum nanoscience

NIST quantum probe enhances electric field measurements October 8th, 2014

Quantum environmentalism: Putting a qubit's surroundings to good use October 2nd, 2014

Rice launches Center for Quantum Materials: RCQM will immerse global visitors in cross-disciplinary research September 30th, 2014

Big Results Require Big Ambitions: Three young UCSB faculty receive CAREER awards from the National Science Foundation September 18th, 2014

NanoNews-Digest
The latest news from around the world, FREE





  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE