The Bloch Oscillations and THz Electroluminescence in Natural Superlattices of 6H-, 8H-SiC Polytypes

We report on the observation of the THz electroluminescence in 6H-SiC and 8H-SiC n+–n-–n+ structures of hexagonal crystals with natural superlattice, caused by applied electrical field along the lattice and natural superlattice axis. It is shown that there are the terahertz electroluminescence correspond to the narrow lines at 5.3–12.7 meV. The emission channel can be well explained by the optical intraladder transitions in the Bloch oscillations regime.