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 similar to380 mK. The minimum noise temperature of the first amplifier version is below 110+/-25 mK(similar to80+/-20 hf/k(B)) at 28.6 MHz, estimated from the noise of input 10 kOmega resistance and coupled input tank circuit with an active resistance at the resonant frequency R-S(f(0))approximate to17.9 kOmega. 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(similar to100+/-25 hf/k(B)) at 26.8 MHz was estimated when coupled to an input tank circuit with R-S(f(0))approximate to61.8 kOmega. The power consumption of the amplifiers is in the range of 100-600 muW. (C) 2004 American Institute of Physics.