Optical properties of GaN/AlGaN nanostructures in the terahertz frequency range

Optical transmission and reflection for a single GaN/AlGaN heterojunction grown on sapphire have been investigated with high and low spectral resolution in the spectral range of 8–47 meV. For comparison, the same spectra have been measured for the sapphire substrate. Refractive index dispersion has been determined for sapphire from the spectra measured with high resolution. Then the data on 2D electron absorption in the GaN/AlGaN heterojunction were obtained from the low resolution spectra. The spectra of terahertz emission from the GaN/AlGaN heterojunction under 2D electron heating in strong electric field have been measured for the first time.