A cryogenic amplifier for fast real-time detection of single-electron tunneling

TL;DR

This paper presents a cryogenic HEMT amplifier that significantly enhances the bandwidth and speed of single-electron tunneling detection in quantum dot systems, enabling real-time monitoring of rapid charge fluctuations.

Contribution

The work introduces a cryogenic HEMT amplifier operating at 1K with a 1 MHz bandwidth, improving detection speed and sensitivity for single-electron tunneling events.

Findings

Achieved 400 ns resolution in monitoring charge fluctuations.

Amplifier noise is only a few times higher than shot noise.

Enabled real-time detection of single-electron tunneling.

Abstract

We employ a cryogenic High Electron Mobility Transistor (HEMT) amplifier to increase the bandwidth of a charge detection setup with a quantum point contact (QPC) charge sensor. The HEMT is operating at 1K and the circuit has a bandwidth of 1 MHz. The noise contribution of the HEMT at high frequencies is only a few times higher than that of the QPC shot noise. We use this setup to monitor single-electron tunneling to and from an adjacent quantum dot and we measure fluctuations in the dot occupation as short as 400 nanoseconds, 20 times faster than in previous work.