Optimized response of the AlGaN/GaN heterostructure with asymmetric gratings at oblique incidence in the terahertz regime

The performance of terahertz (THz) detectors based on two-dimensional electron gas (2DEG) with the aid of a subwavelength gratings coupler depends critically on the amplitude difference of an electric field with positive and negative scattering orders. An efficient method was proposed to enhance the current response of the AlGaN/GaN material in the frequency range from 0 to 5 THz under oblique incidence of THz radiation with asymmetric gratings, where the optimal incidence angle exists. The case of symmetric gratings was also studied for comparison. The results will be useful for the theoretical and experimental optimization of grating-assisted THz detectors without electrical bias.