Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

Flipping the switch on supramolecular electronics August 14th, 2018

New technology can detect hundreds of proteins in a single sample: Improvement of barcoding technique offers cost-effective alternative to current technology August 13th, 2018

Biomimetic micro/nanoscale fiber reinforced composites August 10th, 2018

Breaking down the Wiedemann-Franz law: In a study exploring the coupling between heat and particle currents in a gas of strongly interacting atoms, physicists at ETH Zurich find puzzling behaviours August 10th, 2018

Physics

Yale-NUS scientist and collaborators solve open theoretical problem on electron interactions August 10th, 2018

World-first quantum computer simulation of chemical bonds using trapped ions: Quantum chemistry expected to be one of the first applications of full-scale quantum computers July 25th, 2018

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern July 21st, 2018

World's fastest man-made spinning object could help study quantum mechanics July 20th, 2018

Govt.-Legislation/Regulation/Funding/Policy

Flipping the switch on supramolecular electronics August 14th, 2018

New technology can detect hundreds of proteins in a single sample: Improvement of barcoding technique offers cost-effective alternative to current technology August 13th, 2018

Breaking down the Wiedemann-Franz law: In a study exploring the coupling between heat and particle currents in a gas of strongly interacting atoms, physicists at ETH Zurich find puzzling behaviours August 10th, 2018

Yale-NUS scientist and collaborators solve open theoretical problem on electron interactions August 10th, 2018

Discoveries

Flipping the switch on supramolecular electronics August 14th, 2018

New technology can detect hundreds of proteins in a single sample: Improvement of barcoding technique offers cost-effective alternative to current technology August 13th, 2018

Biomimetic micro/nanoscale fiber reinforced composites August 10th, 2018

Breaking down the Wiedemann-Franz law: In a study exploring the coupling between heat and particle currents in a gas of strongly interacting atoms, physicists at ETH Zurich find puzzling behaviours August 10th, 2018

Announcements

Flipping the switch on supramolecular electronics August 14th, 2018

New technology can detect hundreds of proteins in a single sample: Improvement of barcoding technique offers cost-effective alternative to current technology August 13th, 2018

Biomimetic micro/nanoscale fiber reinforced composites August 10th, 2018

Breaking down the Wiedemann-Franz law: In a study exploring the coupling between heat and particle currents in a gas of strongly interacting atoms, physicists at ETH Zurich find puzzling behaviours August 10th, 2018

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

Breaking down the Wiedemann-Franz law: In a study exploring the coupling between heat and particle currents in a gas of strongly interacting atoms, physicists at ETH Zurich find puzzling behaviours August 10th, 2018

Carbon is the new black: Researchers use carbon nanotubes to develop clothing that can double as batteries July 10th, 2018

NIST Researchers Simulate Simple Logic for Nanofluidic Computing June 30th, 2018

BNAs improve performance of Li-ion batteries June 27th, 2018

Research partnerships

Breaking down the Wiedemann-Franz law: In a study exploring the coupling between heat and particle currents in a gas of strongly interacting atoms, physicists at ETH Zurich find puzzling behaviours August 10th, 2018

Yale-NUS scientist and collaborators solve open theoretical problem on electron interactions August 10th, 2018

Scientists squeeze nanocrystals in a liquid droplet into a solid-like state and back again: Simple chemical technique transforms crystal mixture where 2 liquids meet August 9th, 2018

Quantum chains in graphene nanoribbons: Breakthrough in nanoresearch August 9th, 2018

Quantum nanoscience

Breaking down the Wiedemann-Franz law: In a study exploring the coupling between heat and particle currents in a gas of strongly interacting atoms, physicists at ETH Zurich find puzzling behaviours August 10th, 2018

Quantum chains in graphene nanoribbons: Breakthrough in nanoresearch August 9th, 2018

World-first quantum computer simulation of chemical bonds using trapped ions: Quantum chemistry expected to be one of the first applications of full-scale quantum computers July 25th, 2018

World's fastest man-made spinning object could help study quantum mechanics July 20th, 2018

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project