Thermal radiation intensities in mid-infrared region from semiconductor-metal micro-grating structure

Thermal emissions from metal/dielectric-material stripe structures on the surface of dielectric materials are observed. These emissions are attributed to electric-dipole emissions induced by coherent thermal lattice vibrations in the surface structures of a few micrometers. The structures on undoped GaAs and GaP show the emission close to the longitudinal optical (LO) phonon energy, while the peak energy of emission from the structures on ZnO and GaN is located in between the LO and transverse optical (TO) mode energies. The emission intensities from GaN and ZnO are stronger than that of GaAs.