Comparison of GaN and InGaAs high electron mobility transistors as zero-bias microwave detectors

We report on the measurements of the two main figures of merit for microwave detection, namely, responsivity and noise equivalent power (NEP), in HEMTs based on two of the most broadly used material systems AlGaN/GaN and AlInAs/InGaAs. A comparison between their performances as RF detectors in a wide temperature range is provided by means of experiments made under probes with direct connection to the drain contact. InGaAs HEMTs exhibit much better responsivity and NEP, which are further improved when lowering the working temperature. Moreover, we analyze the possibility of optimizing the current-mode detection of the transistors by improving the impedance matching conditions through an adequate choice of the device width W.