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PbTe single crystals doped with monovalent Au or Cu were grown using the Bridgman method. Far infrared reflectivity spectra were measured at room temperature for all samples and plasma minima were registered. These experimental spectra were numerically analyzed and optical parameters were calculated. All the samples of PbTe doped with Au or Cu were of the "n" type. The properties of these compositions were analyzed and compared with PbTe containing other dopants. The samples of PbTe doped with only 3.3 at% Au were the best among the PbTe + Au samples having the lowest plasma frequency and the highest mobility of free carriers-electrons, while PbTe doped with Cu was the opposite. Samples with the lowest Cu concentration of 0.23 at% Cu had the best properties. Thermal diffusivity and electronic transport properties of the same PbTe doped samples were also investigated using a photoacoustic (PA) method with the transmission detection configuration. The results obtained with the far infrared and photoacoustic characterization of PbTe doped samples were compared and discussed. Both methods confirmed that when PbTe was doped with 3.3 at% Au, thermoelectric and electrical properties of this doped semiconductor were both significantly improved, so Au as a dopant in PbTe could be used as a new high quality thermoelectric material. © 2015 Pantelija M. Nikolic et al.

Far infrared reflectivity spectra of polycrystalline In1−xGaxSb were measured and numerically analyzed using the classical dispersion formula and also a fitting procedure based on the modified plasmon-phonon interaction model in the temperature range from 10 K to 300 K. Optical parameters were calculated and discussed. A local mode belonging to the GaSb rich end and two-mode behavior were observed at low temperatures

Single crystals of lead telluride doped with Nd were synthesized using the Bridgeman method. Room temperature far infrared reflectivity spectra were measured for PbTe samples with Nd content in the range 0.2-0.9 at.%. Optical reflectivity in the far infrared range was measured in the temperature range between 10 and 300 K for a highly polished PbTe sample with 0.6 at.% Nd. The experimental diagrams were numerically analyzed with a fitting procedure using a modified plasmon-phonon model. Two local modes were noted and their origin was discussed. Optical electron mobility was calculated for all analyzed samples.

Single crystal samples of PbTe doped with Hg were grown using the Bridgman method. Far infrared reflectivity spectra were measured at room temperature for samples with 0.5 at. % Hg; 0.9 at. % Hg and 1.4 at. % Hg. The plasma frequency decreased when PbTe was doped with Hg and it was lowest for the PbTe sample doped with 0.5 at. % Hg. The values of the determined optical free carrier mobility increased and was the highest for PbTe doped with 0.5 at. % Hg.

Single crystal samples of lead telluride doped with Pr were produced using the Bridgman method. Far infrared spectra of the samples doped with 0.15 at%, 0.25 at% and 0.6 at% Pr are presented. The experimental data were numerically analyzed using a fitting procedure based on the plasmon-phonon interaction model and optical parameters were determined. Two local modes of praseodium were observed at about 158 cm-1 and 257 cm-1 at room temperature. The origin of the local modes was discussed. © 2008 Elsevier B.V. All rights reserved.

The starting mixtures of ZnO, TiO2, and MgO (0, 1.25, and 2.5 wt.%) powders are mechanically activated in a high-energy planetary mill for 15 min and then sintered between 800 and 1100°C for 2 h. The influence of MgO addition on the structure of the samples obtained is analyzed with X-ray diffraction and infrared reflection spectroscopy. Room-temperature far-infrared reflectivity spectra of the samples doped with MgO (0, 1.25, and 2.5 wt.%) and sintered at 1100 °C in the frequency range between 100 and 1200 cm- 1 are measured and analyzed. Optical parameters are determined for seven oscillators belonging to the spinel structure using the four-parameter model of coupled oscillators. Born effective charges are calculated from the transversal/longitudinal splitting. © 2009 Springer Science+Business Media, Inc.

PbTe and Pb0.85Sn0.15Te single crystals, doped with Pd, were grown using the Bridgman method. Far infrared spectra were measured in the temperature range between 10 K and 300 K. The experimental spectra were numerically analyzed using first the Kramers-Krönig method and then a fitting procedure, based on the plasmon-phonon interaction model, and the optical parameters were calculated. Since the electronic structure of the ionized state for Pd, Ni and Pt is of the same type, and the influence of d-shells is very strong, special attention was paid to the influence of the electronic structure of dopants on the final properties PbTe and PbSnTe crystals. © 2008 Elsevier B.V. All rights reserved.

Far infrared reflectivity spectra of sintered Pb 0.9Sn 0.1Te doped with 0.2 and 2 at.% Pd are measured. The experimental results are analyzed using a fitting procedure based on a modified plasmon-phonon interaction model. The values of calculated parameters are compared with literature data for PbTe and PbSnTe single crystal samples doped with palladium and nickel, with the purpose of determining whether the sintered samples can be used in different devices instead of single crystals. © 2009 Springer Science+Business Media, Inc.

Single crystal samples of lead telluride doped with Gd were grown using the Bridgman method. Far infrared reflectivity spectra in the temperature range from 10 K to 300 K were measured. The experimental diagrams were numerically analyzed using a fitting procedure based on the plasma-phonon interaction model and the optical parameters were determined, while two local modes of gadolinium were observed at about 155 cm-1 and 230 cm-1 at room temperature. The origin of these local vibrational impurity modes was discussed. © 2008 Elsevier B.V. All rights reserved.

Single crystal samples of lead-telluride doped with Ytterbium were made using the Bridgman method. Far infrared reflectivity spectra in the temperature range from 10 to 300 K were measured. Analysis of the experimental spectra was made using a fitting procedure based on the model of plasma-phonon interactions and the optical parameters were calculated. Two local impurity modes of Ytterbium were observed at about 160 and 250 cm-1. © 2007.

Single-phase zinc-stannate thin films of different thickness values were prepared by radio frequency magnetron sputtering on a silica substrate. Rietveld analysis of X-ray diffraction data confirmed that the films had an inverse spinel structure, with a cation inversion parameter of 0.8. Room temperature far and mid infrared reflectivity spectra were measured in the range 50-4000 cm- 1. The reflectivity diagrams were analyzed using the four-parameter model of coupled oscillators for optical phonons with a standard multi-layer technique taking into account the thin-film layer and the substrate. The optical parameters were determined for seven oscillators belonging to the spinel structure. Their origin was discussed in relation to non-stoichiometry of the thin film and cation disorder in the crystal lattice. Born effective charges were calculated from the transversal/longitudinal splitting. © 2007 Elsevier B.V. All rights reserved.

Zinc-titanate ceramics were obtained by initial mechanical activation in a high-energy planetary mill for 15 min followed by sintering at temperatures 900-1100°C for 2 h. Room temperature far infrared reflectivity spectra for all samples were measured in the range 100-1200 cm-1. The same ionic oscillators were present in the measured spectra, but their intensities increased with the sintering temperature in correlation with the increase in sample density and microstructure changes. Optical parameters were determined for seven oscillators belonging to the spinel structure using the four-parameter model of coupled oscillators. Born effective charges were calculated from the transversal/longitudinal splitting. © 2008 Springer Science+Business Media, LLC.

Far infrared reflectivity spectra of single crystal PbTe doped with Bi were measured and numerically analyzed using a fitting procedure based on a modified plasmon-phonon interaction model with two additional oscillators at about 140 and 219 cm-1 which represents local Bi impurity modes. The position of observed plasma minimum and the values of the calculated parameters were compared with the literature data for pure single crystal PbTe which shows that bismuth improved the basic properties of the host crystal a lot. © 2008 Springer Science+Business Media, LLC.

The effects of Bi2O3 addition on the phase composition, microstructure and optical properties of ZnO-SnO2 ceramics were investigated. Starting powders of ZnO and SnO2 were mixed in the molar ratio 2:1. After adding Bi2O3 (1.0 mol.%) this mixture was mechanically activated for 10 min in a planetary ball mill, uniaxially pressed and sintered at 1300°C for 2 h. Far-infrared reflection spectra were measured (100-1000 cm-1). To investigate the occurred differences in FTIR spectra, the Bi2O3-doped sample was examined more carefully with a Perkin-Elmer FTIR spectrometer (Perkin Elmer, Waltham, MA, USA) connected with a Perkin-Elmer FTIR microscope and itemized points of interest were also studied with SEM-EDS. © 2008 The Authors.

Room temperature far infrared reflectivity spectra of single phase spinel zinc-stannate thin films, prepared by rf magnetron sputtering on a glass substrate, and bulk sintered samples were measured. The sintered samples were obtained by mechanical activation of starting ZnO and SnO2 powders for 10 min followed by sintering at 1300 degrees C for 2 h. The reflectivity diagrams obtained for bulk samples were numerically analyzed using the four-parameter model of coupled oscillators. The optical parameters were determined for six observed ionic oscillators belonging to the spinel structure and two additional oscillators originating from the sintering procedure resulting from pores and grain boundaries. The reflectivity diagrams obtained for thin film samples were analyzed using the four-parameter model for optical phonons with a standard optical multi-layer technique.

Single phase complex spinel (Mn, Ni, Co, Fe)(3)O-4 samples were sintered at 1050, 1200 and 1300 degrees C for 30 min and at 1200 degrees C for 120 min. Morphological changes of the obtained samples with the siDtering temperature and time were analyzed by X-ray diffraction and scanning electron microscope (SEM). Room temperature far infrared reflectivity spectra for all samples were measured in the frequency range between 50 and 1200 cm(-1). The obtained spectra for all samples showed the presence of the same oscillators, but their intensities increased with the sintering temperature and time in correlation with the increase in sample density and microstructure changes during sintering. The measured spectra were numerically analyzed using the Kramers-Kronig method and the four-parameter model of coupled oscillators. Optical modes were calculated for six observed ionic oscillators belonging to the spinel structure of (Mn, Ni, Co, Fe)(3)O-4 of which four were strong and two were weak.

Polarized far- and mid-infrared reflectance spectra were measured at room temperature for the new mineral species jarandolite, CaB3O4(OH)(3), for the two principal directions. Thirty three vibration modes for (E) over right arrow parallel to(c) over right arrowc and 32 for (E) over right arrow perpendicular to(c) over right arrow were observed and analysed numerically. Symmetry analysis predicts 41 (E) over right arrow parallel to(c) over right arrow and 40 (E) over right arrow perpendicular to(c) over right arrow vibration modes that include lattice and O-H modes. Mode assignment was made based on the structure of jarandolite. The values of the mode frequencies (omega(TO)), the damping factors (gamma) and the oscillator strength (S) of each oscillator were obtained by fitting to a Lorentz model.