The stabilizing effect of indium on (Ag,In) doped CdSe quantum dots and the influence of the Ag precursor Ag4Cl4(PPh3)4 on morphology have been revealed.

Vibrational properties of PbTe single crystals doped with Ni are determined using far - infrared spectroscopy in wide temperature range. Far - infrared reflection spectra were analyzed using a fitting procedure based on the modified plasmon - ionised impurity - phonon interaction model. Together with the strong coupling we obtained three local modes of Ni at about 130, 165 and 190 cm(-1), which correspond to the impurity atoms in different valence states. The positions of these modes depend on the impurity center charge, while their intensities depend on the temperature and Ni concentration.

Far - infrared and magnetic properties of Co doped PbTe (ZCo = 4 x 10(19) at./cm(3)) single crystal are investigated in a broad range of temperature and magnetic fields. Far - infrared reflection spectra were analyzed using a fitting procedure based on the modified plasmon - ionised impurity - phonon interaction model. Together with the strong coupling we obtained three local modes of Co at about 125, 190 and 275 cm(-1), which corresponded to the impurity atoms in different valence states. A magnetic measurement shows that doping PbTe by Co causes appearance of paramagnetic properties

Sols of stabilized copper-doped CdSe nanocrystals in a nonpolar high-boiling solvent have been synthesized using cadmium oleate, copper stearate, and trioctylphosphine selenide as starting reagents. The average size of the nanocrystals is 2.8–2.9 nm, with a 10% variance, as evaluated from their absorption spectra. The samples show excitonic luminescence and bright near-IR (700–900 nm) luminescence with a lifetime on the order of 0.5–1 μs. The luminescence spectroscopy data are consistent with the assumption that the copper distribution over the nanocrystals follows Poisson’s law. The average copper content of the samples is 0.1–2 atoms per nanocrystal.

In this paper, we present room temperature unpolarized Raman scattering spectra of Ni doped PbTe single crystal sample. Crystal of PbTe(Ni) was grown by the Bridgman method. The Ni concentration in the sample used here was 1 x 10(19) at./cm(3). Well resolved peaks appear at about 126, 143, 181, 362 and 724 cm(-1). The modes at 126 and 143 cm(-1), which are also observed in other telluride compounds, originate from vibrations in TeO2. We assume that the mode at about 181 cm(-1) is connected to excitations of a local phonon mode in the vicinity of an impurity atom (donor Ni3+ state). Modes at about 362 cm(-1) and 724 cm(-1) are the second and fourth harmonic of a local phonon mode, registered here due to multiphonon emission.

Far-infrared reflection spectra in wide temperature range were used to investigate the vibrational properties of the PbTe single crystals doped with Co. In the analysis of the experimental results we used dielectric function that took into account the existence of plasmon-ionised impurity–phonon interaction. The results obtained from the experimental spectra as the best fit, are in very good agreement with the theoretical prediction. Together with the strong coupling we obtained three local modes of Co at about 125, 190 and 275cm−1, which corresponded to the impurity atoms in different valence states. The positions of these modes depend on the impurity center charge, and their intensities depend on the temperature and Co concentration.

The T-x phase diagram along the PbTe-VTe2 join of the Pb-V-Te system has been studied. Vanadium-doped lead telluride crystals have been grown, and the longitudinal vanadium and carrier profiles in the crystals have been investigated. The temperature dependences of resistivity for the crystals lend support to the conclusion drawn earlier that PbTe〈V〉 is in a semi-insulating state at low temperatures. The crystals offer a high 20-K electron mobility, on the order of 105 cm2/(V s), which attests to high electrical homogeneity of the material and stabilization of the Fermi level.

In this paper, we present far-infrared reflection spectra of Ni doped PbTe single crystal samples. Crystals of PbTe(Ni) were grown by the Bridgman method. These spectra were analyzed using a fitting procedure based on the modified plasmon–phonon interaction model. Together with the strong plasmon–phonon coupling we obtained three local modes of Ni at about 130, 165 and 190cm−1 which correspond to the impurity atoms in different valence states. The positions of these modes depend on impurity center charge, and their intensities depend on temperature and Ni concentration.

We have studied a portion of the ternary system Pb-V-Te. Pseudobinary joins have been identified, the vanadium solubility along the V3Te4-PbTe join has been determined, and the lattice parameter of the solid solution has been measured as a function of vanadium content at 800 and 870°C. Six PbTe〈V〉 crystals have been grown by the Bridgman method, and their microstructure and transport properties have been investigated. The results indicate that vanadium in PbTe is not a simple donor: its effect depends on those growth conditions that determine the degree of compensation of the donor effect of vanadium and native defects. PbTe〈V〉 samples have been found to pass into a high-resistivity state on cooling and to be photosensitive. The depth of the vanadium donor level in the band gap of lead telluride has been evaluated.

Based on experimental data, we have found conditions for the melt growth of Tm-doped PbTe crystals without phase segregation and for the synthesis of a homogeneous growth charge. The longitudinal thulium distribution in the grown crystals has been assessed. The results indicate the formation of an extended diffusion layer in the melt during crystal growth. The crystals are found to contain various types of inclusions. At high concentrations of Tm in PbTe crystals, it acts as a donor.

The phase compatibility diagram of the Pb-Tm-Te system is constructed, and the pseudobinary joins in the Pb-TmTe-Te system at 850°C are identified. A partial phase diagram of the PbTe-Tm2Te3 join is mapped out using x-ray diffraction and differential thermal analysis data. The lattice parameter of PbTe〈Tm〉 solid solutions is determined as a function of thulium content at the Pb- and Te-rich phase boundaries of lead telluride.

Vapor growth of In-doped PbTe crystals by the sublimation–condensation and vapor–liquid–solid (VLS) processes is examined. Well-faceted Pb 1 – x In x Te crystals with x = 0.04–0.06 are prepared by the sublimation method. The effects of the charge composition on the facial development and growth rate in the range 0 ≤ x ≤ 0.02 are discussed. The growth process at x ≥ 0.02 is shown to follow the VLS mechanism. Bulk Pb 1 – x In x Te crystals with x ≤ 0.05 are grown by a vertical VLS process. The crystal composition is shown to depend significantly on the rate of ampule translation through the temperature field of the furnace and the separation between the evaporation and condensation zones. The longitudinal indium profiles in the crystals are correlated with growth kinetics.

Kinetic analysis of the vapor–liquid–solid growth of crystals of solid solutions is carried out in terms of a directional solidification model, using Pb0.8Sn0.2Te as an example. The growth regimes are analyzed which favor the formation of a diffusion layer at interfaces, and the conditions are identified which allow one to grow crystals with a uniform longitudinal SnTe distribution. The conclusions drawn from the analysis are supported by experimental data on the crystal growth of Pb0.8Sn0.2Te from a fully or partially molten charge.

A relationship between the real crystal structure and the doping level was proposed based on experimental data on the real structures of PbTe crystals with different Cr, Co, Ni, and In contents. Two composition regions were revealed for these crystals. One region is characterized by the presence of impurity atmospheres at dislocations as the main type of impurity inhomogeneity, whereas impurity-rich microprecipitates prevail in the second region. Possible reasons for the formation of solid solutions supersaturated with impurity ions were analyzed. The influence of thermal treatment on the real structure and galvanomagnetic properties of the crystals was investigated.

The longitudinal dopant distributions in PbTe crystals are analyzed. The experimental indium profiles in Bridgman-grown PbTe〈In〉 crystals are well fitted by the Tiller equation. The Sn distribution in the PbTe〈Sn〉 crystals grown by the vapor-liquid-solid mechanism depends strongly on the rate-limiting process. If the growth rate is controlled by processes other than mass transport, the Sn distribution is more uniform

The effect of isothermal annealing on the microstructure of PbTe crystals doped with Cr, Co, Ni, Ga, and In was studied. The materials studied differed in dopant content and real structure (density of dislocations, inclusions, and precipitates). Annealing was found to promote dopant outdiffusion and the growth of microprecipitates, reducing the concentration of electrically active, donor impurities. The effect of annealing depends on the nature and concentration of the dopant.

Pure and copper-doped tin dioxide films were prepared by pulsed laser ablation of metallic targets, followed by oxidation. The optimal deposition and oxidation conditions were found. The composition of the metallic and oxidized films was determined by Auger electron spectroscopy and ICP emission spectrometry. Structural characterization;vas performed by x-ray diffraction. Scanning electron microscopy, x-ray diffraction, and high-temperature optical microscopy data demonstrate that the microstructure of the films depends on laser-beam power density as well as on substrate temperature. Most uniform grain-size distributions were obtained at substrate temperatures from 50 to 70 and from 280 to 300 degrees C. The copper dopant has no effect on film microstructure. Long-term oxidizing annealing leads to copper enrichment in the near-surface region.