Room temperature tunable detection of subterahertz radiation by plasma waves in nanometer InGaAs transistors

The authors report on the demonstration of room temperature, tunable terahertz detection obtained by 50nm gate length AlGaAs∕InGaAs high electron mobility transistors (HEMTs). They show that the physical mechanism of the detection is related to the plasma waves excited in the transistor channel and that the increasing of the drain current leads to the transformation of the broadband detection to the resonant and tunable one. They also show that the cap layer regions significantly affect the plasma oscillation spectrum in HEMTs by decreasing the resonant plasma frequencies.