Draft Specifications for the Programmable Quantum Current Generator Wide range quantum-accurate current source e-SI-Amp partner Laboratoire national de métrologie et d’essais (LNE) have been developing a wide range, quantum-accurate current generator which uses a combination of Josephson and Quantum Hall devices. Unlike single-electron based hardware developed within the e-SI-Amp project, which only operates at very low currents, the Programmable Quantum Current Generator (PQCG)… Read More
Single electron pumps @NPL Open Day The UK’s National Physical Laboratory (NPL) holds an open day every two years, inviting members of the public into the laboratory to see the laboratories and talk to measurement scientists. This year more than 3300 visitors were admitted to the site. The tour of the facilities included the laboratories where single electron devices are developed… Read More
Helmholtz Prize awarded for small current research The 2018 Helmholtz prize for “Precision Measurements in Applied Measurement Technology” has been awarded to e-SI-Amp partners PTB for work on improvements in the accurate measurement and generation of small currents. Prizes are awarded by the Helmholtz Foundation (Germany) for outstanding scientific and technological research in the field of “Precision Measurement in Physics, Chemistry and… Read More
Small Current Systems: The Travelling ULCA Secondary/transfer standards used to capture a calibrated quantity (e.g. resistance) need to be stable, as this is something that can easily limit the reliability of a calibration (rather than the source uncertainty for instance). However, what exactly limits the stability, e.g. aging or thermal/mechanical stresses is a complicated question. The Ultrastable Low-Noise Current Amplifier (ULCA)… Read More
CMOS-compatible electron pumps defined by optical lithography Electron pumps are typically fabricated using lithographic masks defined by electron beams. This process has the high resolution and flexibility required to fabricate prototype single electron devices in Si or GaAs systems, but is relatively slow and not compatible with techniques used for larger scale production of devices, or for integration into a larger device… Read More
Controlling the frequency limits of tunable barrier pumping Tunable barrier pumps in semiconductor devices can drive a clock-controlled pump current and thus represent a prototype quantum current standard. A problem facing any practical electron pumping scheme is that accurate pumping cannot take place at arbitrarily high frequency. In practice this limits accurate pumping to a frequency of order 1 GHz. Scientists at KRISS,… Read More
Single carrier trapping and de-trapping in silicon MOSFETs While lithographically engineered charge traps can be used for single-electron transport, ‘accidental’ single-electron trapping behaviour can also occur, particularly in very small semiconductor devices. This can be a nuisance in some circumstances, but might also provide useful access to single-electron transistor (SET) effects in simple devices. Researchers at e-SI-Amp partner University of Southampton (UoS) and National… Read More
Record accuracy for a silicon single-electron pump The NPL single-electron group, in collaboration with the University of New South Wales (UNSW), Australia, has recently measured the current from a silicon single electron pump with an uncertainty of just 0.27 parts per million (ppm) [1]. Previous measurements of a silicon pump measured by NPL and NTT, Japan were limited to an accuracy of… Read More
National Standards Laboratories International: Best Paper Award Dr. Stephen Giblin from e-SI-Amp partner NPL was awarded the best paper award at the NCSLI workshop and symposium (August 2017, Maryland, USA). NCSL International (NCSLI) (from the founding name “National Conference of Standards Laboratories”) is a global, non-profit organization whose membership is open to any organization with an interest in metrology (the science of measurement) and its application in research,… Read More
Small current instrumentation for Single Charge Aerosol Reference e-SI-Amp partner VTT (Finland), PTB (Germany) and e-SI-Amp stakeholder Tampere University of Technology (TUT, Finland) have been improving the measurement techniques and traceability of small electric currents in the Single Charge Aerosol Reference (SCAR) located at TUT. Aerosol particles may play an important role in global climate change. Fine and ultrafine particles have also found… Read More
