Papers by Keyword: Infrared Reflectance

Abstract: Polarized infrared (IR) reflectance measurement was carried out to investigate the optical phonon modes of wurtzite structure In_0.92Ga_0.08N thin film grown by molecular beam epitaxy. Composition dependence of IR reststrahlen features was observed. Theoretical polarized IR reflectance spectrum was simulated using the standard multilayer optics technique with a multi-oscillator dielectric function model. By obtaining the best fit of experimental and theoretical spectrum, the Brillouin zone center E₁ optical phonon modes together with the dielectric constant, layer thickness, free carriers concentration and mobility were extracted non-destructively. The extracted E₁ optical phonon modes were compared with those generated from modified random element isodisplacement (MREI) model.

Abstract: We study the conditions for appearance and observation of surface and interface phonon-polariton (SPP and IPP) modes in thin InN layers grown on sapphire using AlN buffer. Theoretical dispersion relations of the IPP modes in the system air/InN/AlN/sapphire for different thickness of the InN layer are obtained. Features in the experimentally measured infrared reflectance were associated with the appearance of interface phonon-polariton excitations at wave-numbers between the TO and LO modes.

Abstract: Glasses reflective in the spectral range of long-wave infrared radiation operate as heat mirrors. These glasses have found wide applications in architecture. Special thin film coatings on glass panes reflect long wave infrared radiation back to building interiors. The reflective thin films limit absorption of infrared radiation within the glass pane and reduce radiation heat losses of glazings. Heat losses of windows could be significantly limited with the coated glasses which are called low-emissivity glazings. The study of materials convenient for infrared reflective coatings, the optimal composition of thin films and their thicknesses is the main topic of the presented paper. The study is based on measurements of spectral characteristics of selected glasses and computer simulations of the thin film composition for applications of window infrared reflective coatings.

Abstract: We have performed a combined investigation of experiment and theory on the infrared reflectance from cubic SiC grown on Si by chemical vapor deposition. A damping behavior of the interference fringes away from the reststrahlen band and a dip or notch within the “flat top” are observed from some samples while they does not occur in high quality 3C-SiC/Si samples. The former is interpreted due to an interfacial transition layer existed between SiC-Si and a rough surface, while the latter can be demonstrated by a three-component effective medium model.