Interaction of terahertz radiation with surface and interface plasmon–phonons in AlGaAs/GaAs and GaN/Al2O3 heterostructures

Surface phonon and plasmon-phonon polari- ton characteristics of GaAs, AlxGa1−xAs/GaAs, and GaN/ Al2O3 layered structures are investigated by means of tera- hertz radiation reflection spectroscopy. The strong resonant absorption peaks and selective emission of the THz radia- tion dependent upon the lattice composition and free elec- tron density in these layered structures are experimentally observed and analyzed.