Resonant Detection and Modulation of Terahertz Radiation by 2DEG Plasmons in GaN Grating-Gate Structures

We observed, for the first time, resonant absorption and modulation of THz radiation by 2DEG plasmons in GaN-based large area grating-gate structures. Transmission spectra of the fabricated grating-gate devices were measured by a commercial FTIR system using a blackbody emitter as broadband radiation source and a CW FIR gas laser. Obtained spectra clearly showed the absorption peaks, which were attributed to the resonance plasmon excitation in the 2DEG at the AlGaN/GaN heterointerface. The results demonstrate the potential of using GaN-based plasmonic device for THz applications.