Gain Dependence of the Noise in the Single Electron Transistor

TL;DR

This paper investigates low frequency noise in single electron transistors, revealing that external charge noise dominates and identifying additional noise sources at low gains, with record low charge noise achieved.

Contribution

It provides a detailed analysis of noise dependence on gain in single electron transistors and introduces a model for excess noise beyond resistance fluctuations.

Findings

External charge noise dominates the output noise.

Additional noise at low gains is not solely due to resistance fluctuations.

Record low charge noise of 9×10^-6 e/√Hz achieved in superconducting and normal states.

Abstract

An extensive investigation of low frequency noise in single electron transistors as a function of gain is presented. Comparing the output noise with gain for a large number of bias points, it is found that the noise is dominated by external charge noise. For low gains we find an additional noise contribution which is compared to a model including resistance fluctuations. We conclude that this excess noise is not only due to resistance fluctuations. For one sample, we find a record low minimum charge noise of qn = 9*10^-6 e/sqrt(Hz) in the superconducting state and qn = 9*10^-6 e/sqrt(Hz) in the normal state at a frequency of 4.4 kHz.