Cryogenic GaAs high-electron-mobility-transistor amplifier for current noise measurements

TL;DR

This paper introduces a cryogenic GaAs HEMT amplifier that significantly improves current-noise measurements in mesoscopic devices at very low temperatures by offering lower noise and higher resolution than commercial alternatives.

Contribution

The work presents a homemade GaAs HEMT amplifier optimized for cryogenic conditions, demonstrating enhanced noise performance and measurement resolution over commercial HEMTs.

Findings

Lower noise floor achieved with homemade HEMT

Enhanced resolution in current-noise measurements

Successful application to quantum point contact measurements

Abstract

We show that a cryogenic amplifier composed of a homemade GaAs high-electron-mobility transistor (HEMT) is suitable for current-noise measurements in a mesoscopic device at dilution-refrigerator temperatures. The lower noise characteristics of our homemade HEMT leads to a lower noise floor in the experimental setup and enables more efficient current-noise measurement than is available with a commercial HEMT. We present the dc transport properties of the HEMT and the gain and noise characteristics of the amplifier. With the amplifier employed for current-noise measurements in a quantum point contact, we demonstrate the high resolution of the measurement setup by comparing it with that of the conventional one using a commercial HEMT.