Towards shot noise-limited detection of a Single-Electron Transistor

A Single-Electron Transistor (SET) is a highly sensitive charge amplifier based on the Coulomb blockade that can operate near the quantum limit: amplification can be accomplished with a back-action close to that required by the uncertainty principle. Its charge sensitivity is ultimately limited to about 1micre/sqrt(Hz) by the shot noise in the source-drain current. Despite the fact that such sensitivity has been approached by some, the shot-noise limit has yet to be reached for either the SET and its RF version, the RF-SET. A scheme is proposed and realized in this thesis for the shot noise-limited detection of a Single-Electron Transistor, based on a DC-SQUID impedance-matched with a DC-biased SET. SQUIDs can operate at the quantum limit, and a microstrip SQUID amplifier has already been demonstrated to operate at almost twice the quantum-limited noise temperature at about 500MHz by M. Muck and collaborators, with a sensitivity sufficient to resolve the SET shot noise. The device has been fabricated and characterized. A 50KOhm resistor has been used as a noise source at low temperature and the measured noise levels have been estimated. Moreover, the detection noise temperature of about 110mK was derived corresponding to a current sensitivity of about 8fA/sqrt(Hz) for the detection of a 100KOhm resistor

Electron Counting Capacitance Standard with an improved five-junction R-pump

The Electron Counting Capacitance Standard currently pursued at PTB aims to close the Quantum Metrological Triangle with a final precision of a few parts in 10^7. This paper reports the considerable progress recently achieved with a new generation of single-electron tunnelling devices. A five-junction R-pump was operated with a relative charge transfer error of five electrons in 10^7, and was used to successfully perform single-electron charging of a cryogenic capacitor. The preliminary result for the single-electron charge quantum has an uncertainty of less than two parts in 10^6 and is consistent with the value of the elementary charge.Comment: 16 pages, 9 figures, 1 tabl

Quantum Metrology Triangle Experiments: A Status Review

Quantum Metrology Triangle experiments combine three quantum electrical effects (the Josephson effect, the quantum Hall effect and the single-electron transport effect) used in metrology. These experiments allow important fundamental consistency tests on the validity of commonly assumed relations between fundamental constants of nature and the quantum electrical effects. This paper reviews the history, results and the present status and perspectives of Quantum Metrology Triangle experiments. It also reflects on the possible implications of results for the knowledge on fundamental constants and the quantum electrical effects.Comment: 36 pages, 8 figure