Comparative analysis of sub-THz detection in graphene, GaN HEMT, and FinFET devices

We studied temperature-dependent photo response in the sub-THz regime (0.14 THz) of graphene and AlGaN/GaN-based field-effect transistors (FETs). Instead of measuring the voltage response using a lock-in amplifier, the current induced by the incoming sub-THz radiations was measured directly using the semiconductor parameters analyzer (SPA). Such an approach allows fast and multiple measurements as a function of temperature. We have observed that, while responsivity increase saturates at 50-100K, depending on the device, the noise equivalent power continues to decrease with the temperature decrease. Our results show the advantage of the graphene-based detectors over the GaN-based ones while operating at low temperatures.