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.
@article{arxiv.2102.11999,
title = {Cryogenic GaAs high-electron-mobility-transistor amplifier for current noise measurements},
author = {Sanghyun Lee and Masayuki Hashisaka and Takafumi Akiho and Kensuke Kobayashi and Koji Muraki},
journal= {arXiv preprint arXiv:2102.11999},
year = {2021}
}