Ultrasensitive radio-frequency pseudomorphic high-electron-mobility-transistor readout for quantum devices

Two versions of a cryogenic multistage pseudomorphic high-electron-mobility field-effect transistor amplifier (based on the AlGaAs/InGaAs/GaAs heterostructure) have been designed for quantum device readout and tested at an ambient temperature ∼ 380 mK . The minimum noise temperature of the first amplifier version is below 110 ± 25 mK ( ∼ 80 ± 20 h f ∕ k B ) at 28.6 MHz, estimated from the noise of input 10 kΩ resistance and coupled input tank circuit with an active resistance at the resonant frequency R S ( f 0 ) ≈ 17.9 k Ω . Its minimum voltage spectral noise density, with respect to the input, is about 200 pV ∕ ( Hz ) 1 ∕ 2 and the corner frequency of the 1 ∕ f noise is close to 300 kHz. For the amplifier with the lowest designed back action, the minimum noise temperature below 130 ± 30 mK ( ∼ 100 ± 25 h f ∕ k B ) at 26.8 MHz was estimated when coupled to an input tank circuit with R S ( f 0 ) ≈ 61.8 k Ω . The power consumption of the amplifiers is in the range of 100-600 μW.