On March 20 and 21, 2019, the workshop “Ultrastable Low-Noise Current Amplifier (ULCA) in Laboratory Practice” was held at PTB. The ULCA is a commercially available instrument, developed by PTB, that enables the measurement and generation of small currents with the highest accuracy. This was attended by sixteen participants from national metrology institutes, the international metrology coordinating body… Read More


OSRAM is a large multinational lighting manufacturer and lighting solution-provider. Historically producing incandescent light bulbs – their name is a portmanteau of filament materials Osmium and Wolfram – they are now one of the largest manufacturers of optoelectronic semiconductors in the world. Supported by e-SI-Amp partners PTB, the OSRAM reference laboratory are now using the ULCA… Read More


The Ultra-Low DC Current source (ULCS) is a small current generating tool developed at Tubitak/UME. This provides a small reference current for the calibration of measuring instruments at very low currents. This instrument has recently been integrated into usage in the TUBITAK UME Optical calibration lab. This ULCS is based on ‘capacitor ramp’ methods (a linear… Read More


During the e-SI-Amp project there have been many opportunities for in-depth training, typically in the operation of electron pumps, or in high accuracy small current measurements (and associated noise debugging). One particular example, which includes many of these activities, is the training that PhD student Ilaria Finardi (INRiM) received while a guest at PTB, Braunschweig.… Read More


The e-SI-Amp sample package Working with the manufacturer of bespoke cryogenic components Aivon, we have developed a sample enclosure for electron pump samples compatible with cryostats at VTT, NPL and Aalto. This can be used to test the universality of different electron pump architectures and the robustness of electron pump performance when the same device… Read More


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


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


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


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


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