Measurement of sub-picoampere direct currents with uncertainties below ten           attoamperes

Krause, Christian; Drung, D.; Scherer, H.

doi:10.1063/1.4975826

Cited by 26 publications

(16 citation statements)

References 19 publications

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“…One variant with a particularly low noise of 1.7 fA/√Hz is now available. In combination with a suitable low‐noise wiring in the cryogenic setup, experiments have indicated that a current of 100 pA sourced by an SEP can realistically be measured with a relative standard uncertainty lower than 0.1 µA A −1 within less than one day: as shown in ref. [] the Allan deviation of the current measured reaches the 0.1 µA A −1 level after about 15 h. Possible strategies for directly involving a QHR together with a JVS in a QMT setup are discussed in ref.…”

Section: Applications Of Single‐electron Pumps As Quantum Current Stamentioning

confidence: 98%

Single‐Electron Pumps and Quantum Current Metrology in the Revised SI

Scherer

Schumacher

2019

Annalen der Physik

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Section: Applications Of Single‐electron Pumps As Quantum Current Stamentioning

confidence: 98%

Single‐Electron Pumps and Quantum Current Metrology in the Revised SI

Scherer

Schumacher

2019

Annalen der Physik

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“…The strength of the additional intra-doublet transition which we propose to exploit in our short QD is 10 4 in the same units, leading to a photocurrent of the order of 5-10 fA, which is already measurable. [86][87][88][89] Increasing the coupling to the leads decreases the amplitude of the broadened absorption peaks, but enhances the current. As shown in Fig.…”

Section: A Short Qd -Tunable Thz Sensormentioning

confidence: 99%

Metallic carbon nanotube quantum dots with broken symmetries as a platform for tunable terahertz detection

Buchs

Margańska

González

et al. 2021

Applied Physics Reviews

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Generating and detecting radiation in the technologically relevant range of the so-called terahertz gap (0.1 − 10 THz) is challenging because of a lack of efficient sources and detectors. Quantum dots in carbon nanotubes have shown great potential to build sensitive terahertz detectors usually based on photon-assisted tunnelling. A recently reported mechanism combining resonant quantum dot transitions and tunnelling barriers asymmetries results in a narrow linewidth photocurrent response with a large signal-to-noise ratio under weak THz radiation. That device was sensitive to one frequency, corresponding to transitions between equidistant quantized states. In this work we show, using numerical together with scanning tunnelling spectroscopy studies of a defect-induced metallic zigzag single-walled carbon nanotube quantum dot that simultaneously breaking various symmetries in metallic nanotube quantum dots of arbitrary chirality strongly relaxes the selection rules in the electric dipole approximation, and removes energy degeneracies. This leads to a richer set of allowed optical transitions spanning frequencies from 1 THz to several tens of THz, for a ∼10 nm quantum dot. Based on these findings, we propose a terahertz detector device based on a metallic single-walled carbon nanotube quantum dot defined by artificial defects. Depending on its length and contacts transparency, the operating regimes range from a high-resolution gate-tunable terahertz sensor to a broadband terahertz detector. Our calculations indicate that the device is largely unaffected by temperatures up to 100 K, making carbon nanotube quantum dots with broken symmetries a promising platform to design tunable terahertz detectors that could operate at liquid nitrogen temperatures.

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“…In the process of SET development, not only SET devices but also other measurement instruments have been drastically improved. At the PTB, the so‐called ultrastable low‐noise current amplifier (ULCA) has been recently developed and commercialized. This will be a key component in making SI traceable measurements of small DC currents as low as attoamperes with a reasonably low uncertainty of ∼10 ppm, not only in laboratories but in real industrial applications .…”

Section: Set Effect and Current Standardsmentioning

confidence: 99%

Review of quantum electrical standards and benefits and effects of the implementation of the ‘revised SI’

Kaneko

2017

IEEJ Transactions Elec Engng

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In the present International System of Units (SI), the Josephson effect and quantum Hall effect have been utilized for voltage and resistance primary standards, and the electrical current standard has been derived from a combination of the two quantum standards. In 2018, it is planned that the SI will be revised based on the latest measurements results of the Planck constant, elementary charge, Avogadro constant, and Boltzmann constant. The adoption of the 'Revised SI' means we shall finally terminate the traceability of the kilogram tied to an artifact (the international prototype of the kilogram) and start a new traceability of the kilogram to the Planck constant h. In electricity and magnetism metrology, and related precision measurements, the traceability presently based on the 'conventional values' of the Josephson constant and the von Klitzing constant is going to be switched to the revised traceability based on the Planck constant and elementary charge. In this article, the foundation of the quantum electrical measurements and how the Revised SI, which is based purely on fundamental physical constants and quantum effects, will bring us a long-term benefit with negligible impact to industry are detailed.

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Measurement of sub-picoampere direct currents with uncertainties below ten attoamperes

Cited by 26 publications

References 19 publications

Single‐Electron Pumps and Quantum Current Metrology in the Revised SI

Single‐Electron Pumps and Quantum Current Metrology in the Revised SI

Metallic carbon nanotube quantum dots with broken symmetries as a platform for tunable terahertz detection

Review of quantum electrical standards and benefits and effects of the implementation of the ‘revised SI’

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