A high-performance temperature sensor based on a p-GaN/AlGaN/GaN hybrid anode diode (HPT-HAD) fabricated by hydrogen plasma treatment is demonstrated. The sensor exhibits accurate and stable temperature responses from 73 to 573 K. The forward anode voltage is linearly proportional to the temperature over the measured temperature range at a fixed current. At a forward current density of 10−7 mA/mm, the device achieves a maximum sensitivity of 1.93 mV/K. The long-time anode current stress measurement reveals that the HPT-HAD shows almost no degradation even at 573 K for 1 h at a current of 100 μA, and the anode voltage shifts only 120 mV at 573 K for 1000 s at 1 nA. This work shows that the HPT-HAD temperature sensor can be reliably operated over a wide temperature range from cryogenic to high temperatures, so can be used in a variety of extreme environments.

We describe the temperature-dependence polarization properties of grating-gated AlGaN/GaN heterostructures at terahertz frequencies. Using the finite-difference time-domain method, it was demonstrated that as the temperature increases, the resonant frequency of the incident light was red-shifted. Simultaneously, a shorter gate length leads to a higher resonant frequency. In addition, at a lower temperature, the coupling efficiency of terahertz radiation and plasmon is higher. In our simulation results, the maximum modulation depth is 88%; at a gate length of 800 nm and lattice temperature of 77 K. For the same gate length, with higher electron gas concentrations and filling factor, greater modulation depths were produced. Studies on these properties may help in the design and optimization of terahertz detectors and modulators.

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