Oh no, you're thinking, yet another cookie pop-up. Well, sorry, it's the law. We measure how many people read us, and ensure you see relevant ads, by storing cookies on your device. If you're cool with that, hit “Accept all Cookies”. For more info and to customize your settings, hit “Customize Settings”.

Review and manage your consent

Here's an overview of our use of cookies, similar technologies and how to manage them. You can also change your choices at any time, by hitting the “Your Consent Options” link on the site's footer.

Manage Cookie Preferences
  • These cookies are strictly necessary so that you can navigate the site as normal and use all features. Without these cookies we cannot provide you with the service that you expect.

  • These cookies are used to make advertising messages more relevant to you. They perform functions like preventing the same ad from continuously reappearing, ensuring that ads are properly displayed for advertisers, and in some cases selecting advertisements that are based on your interests.

  • These cookies collect information in aggregate form to help us understand how our websites are being used. They allow us to count visits and traffic sources so that we can measure and improve the performance of our sites. If people say no to these cookies, we do not know how many people have visited and we cannot monitor performance.

See also our Cookie policy and Privacy policy.

This article is more than 1 year old

NTT thinks it's defined the PERFECT AMPERE with a cunning trap

Take one electron, a silicon nanowire and pay very close attention

Researchers from NTT in Japan have demonstrated what they hope will be that company's contribution to the definition of a new ampere: single electron transfer in silicon, at relatively high speed in a charge-confining trap.

The accurate transfer of electrons in one direction provides a high-accuracy measurement of current flow, which is an important part of the long, ongoing international effort to find a more accurate standard of the ampere.

As readers of The Register will be aware, international efforts to tie down our measurement units to basic physical units have been going on for some time, with the kilogram's silicon globes also key to a better standard.

As NTT writes, “In the new SI units, the value of the elementary charge e, which has so far been determined from measurements, is fixed and the ampere is set from the fixed value. It is therefore desirable to realise the current standard using single-electron transfer because it directly connects e to the ampere”.

The NTT researchers are particularly pleased that they've been able to handle single-electron transfers at frequencies up to 3.5 GHz, since trying to count off enough electrons for an ampere one-at-a-time would take an unfeasibly long time. Achieving the feat at 17 Kelvin is a plus as well, and NTT believes it's going to be able to achieve an error rate below 10 -8, which would also satisfy the gods of international standards.

The company hit the mark by fabricating two transistors with fine gate electrodes on a silicon nanowire. Applying a negative voltage to the gates forms a “single-electron island”, and the clock signal is used to control the release of single electrons from the gates. ®

 

Similar topics

TIP US OFF

Send us news


Other stories you might like