Detection of microwave radiation by electronic fluid in AlGaN/GaN heterostructure field effect transistors

We demonstrate, for the first time, the operation of a novel microwave detector that utilizes the AlGaN/GaN Heterostructure Field Effect Transistor (HFET). Such a detector can operate in two regions. At high frequencies (typically much higher than the HFET cutoff frequency) and in devices with a high electron mobility, the detector operates in a resonance mode with an extremely high predicted peak responsivity (several orders of magnitude higher than for standard Schottky diode detectors). At low frequencies, the detector operates in a non-resonant mode with a predicted responsivity varying from zero to approximately 600 V/W. The detectors in this paper were fabricated using AlGaN/GaN HFET chip devices with the gate lengths varying from 1 to 5 μm, the gate width of 50 μm, and the gate-to-channel distance of 330 Å. The detectors operated in a non-resonant mode at frequencies from 0.05 to 20 GHz. The measured responsivity was on the order of 300 V/W, which is comparable to the responsivity of the state-of-the-art Schottky diode detector. The dependencies of the measured responsivity on the frequency, gate bias and gate length are in agreement with our theory. These results provide valuable guidelines for the design of plasma wave electronics devices operating in the terahertz range