Inorganic Materials (v.46, #4)

Interaction of copper atoms with radiation-induced defects in silicon by L. I. Murin; I. F. Medvedeva; V. P. Markevich (333-338).
The annealing behavior of radiation-induced defects in Czochralski-grown n-type Si crystals doped with copper via high-temperature (600 and 650°) indiffusion has been studied using Hall effect measurements and deep level transient spectroscopy. The results indicate that radiation-induced vacancy-type defects (divacancies V 2 and vacancy-oxygen complexes VO) are effective traps for copper atoms. The inter- action of Cu with VO and V 2 reduces their annealing temperature and leads to the formation of electrically active centers at E c − 0.60 eV and E c − 0.17 eV, which are assumed to be Cu-VO and Cu-V 2 complexes. The enhanced annealing of the radiation-induced vacancy-type defects in Si〈Cu〉 is due to the fact that these defects capture Cu interstitials released from neutral Cu-containing associates at temperatures above 150°C.

We report the structure, microhardness, and stability of rapidly solidified In-Sb foils. The foils have a (101) texture and contain fine InSb particles. Annealing reduces their texture and leads to coalescence of the indium antimonide particles. The InSb particles increase the microhardness of the foils.

A spectrophotometric procedure for hydrogen sulfide determination has been developed and utilized to study the phase diagram of the In-S system using hydrogen as an auxiliary component. Elemental analysis of the hydrogen-containing vapor phase allows the principal thermodynamic properties of the indium sulfides in equilibrium with the vapor phase to be assessed in wide temperature and composition ranges. Our results confirm the existence of a narrow two-phase field between In3−x S4 and In2S′3 (low-temperature phase), which is bounded from above by the peritectic decomposition temperature of (about 415°C). We have determined the temperature-dependent sulfur (S2) vapor pressure over condensed indium sulfides. For the equilibria studied in greatest detail, the present results correlate well with mass spectrometry data for indium sulfides.

ZnIn2S4 and ZnIn2S4:Cu2+ single crystals are shown to exhibit considerable photoconductivity and luminescence anisotropy. The mechanism of carrier recombination in the crystals is polarization-dependent. Their spectra can be understood in terms of optical transitions involving donor and acceptor levels. The degree and spectral distribution of the anisotropy can be tuned via doping and alternating growth of the three- and one-layer polytypes.

Electrical properties and microstructure of Cd x Hg1 − xy Cr y Se crystals by S. Yu. Paranchich; L. D. Paranchich; V. N. Makogonenko; M. D. Andriichuk; V. R. Romanyuk; V. N. Strebezhev; Yu. K. Obedzinskii; E. V. Shchepetil’nikova (349-352).
Crystals of the Cd x Hg1 − xy Cr y Se (x = 0.4, y = 0.1) quaternary solid solution have been grown by the Bridgman method, and their microstructure and electrical properties have been studied. The crystals are shown to contain various types of inclusions in the form of filaments and triangles.

Conductivity piezomodulation in InGaTe2 single crystals by E. M. Gojaev; K. D. Gyul’mamedov; A. R. Ibragimova; A. A. Movsumov (353-357).
An InGaTe2 single crystal has been grown by the Bridgman-Stockbarger method and characterized by X-ray diffraction. The piezomodulation and piezophotomodulation effects in the crystal have been studied as functions of strain and illumination intensity.

Impurities in monosilanes synthesized by different processes by P. G. Sennikov; A. P. Kotkov; S. A. Adamchik; N. D. Grishnova; L. A. Chuprov; S. A. Ignatov (358-363).
Using high-resolution IR spectroscopy, we have compared the impurity compositions of monosilane (SiH4) fractions enriched in impurities in the process of cryofiltration and low-temperature distillation of monosilanes derived from silicon tetrafluoride (SiF4) and trichlorosilane (SiCl3H). The results demonstrate that the more volatile impurities present in both monosilanes are methane (CH4) and carbon dioxide (CO2), whereas the impurities specific to the fluoride-derived monosilane are SiF4, SiF3H, and SiF2H2. The less volatile impurities common to both monosilanes are ethane (C2H6), disiloxane (Si2H6O), and disilane (Si2H6); the impurities specific to the fluoride-derived monosilane are tetrafluoroethylene (C2F4) and monofluorosilane (SiFH3); and those specific to the chloride-derived monosilane are hydrogen chloride (HCl) and the chlorosilanes SiClH3, SiCl2H2, and SiCl3H.

Magnetic properties of the intermetallic compounds RNi (R=Gd, Tb, Dy, Sm) and their hydrides by Yu. L. Yaropolov; V. N. Verbetsky; A. S. Andreenko; K. O. Berdyshev; S. A. Nikitin (364-371).
Hydrogen interaction with RNi intermetallic compounds and the influence of hydrogen on magnetic properties of these compounds were investigated. Ternary hydrides GdNiH3.2, TbNiH3.4, DyNiH3.4 and SmNiH3.7 were prepared by hydrogenation of the initial alloys at room temperature and hydrogen pressure up to 0.1 MPa. Hydrides possess orthorhombic CrB-type structure (S.G. Cmcm). The formation of hydrides results in substantial expansion of the metallic sublattices, weakening of the ferromagnetic interactions and decreasing of the paramagnetic Curie temperatures. The article was translated by the author.

Interaction of ZrFe2 doped with Ti and Al with hydrogen by R. B. Sivov; T. A. Zotov; V. N. Verbetsky (372-376).
The influence of doping with Ti and Al on the structure and hydrogen sorption properties of ZrFe2 was studied by XRD, XRSMA, and measurement of hydrogen absorption and desorption isotherms at pressure up to 300 MPa. The hydrogen capacity and equilibrium desorption pressures of hydrides decrease with increasing Al content at a constant ratio of Ti and Zr. The increase in the Ti content at a constant content of Al in alloys also leads to a decrease in hydrogen capacity; however, the equilibrium desorption pressures of hydrides increase considerably. Zr1−x Ti x (Fe1−y Al y )2 (x= 0.2–0.8; y = 0.05–0.4) alloys were investigated.

Carbon doped titania nanotubes were prepared by anodization of titanium in a fluoride containing ethylene glycol based electrolyte. Anatase crystallization temperature of the nanotubes varied with respect to anodization voltage. A detailed characterization study and mechanistic analysis of formation and stability of anatase phase of the nanotubes is reported. The findings suggest useful heat treatment parameters for obtaining pure anatase phases of the carbon doped titania nanotubes synthesized by anodization at 40 and 60 V.

Synthesis and catalytic performance of V2O5 nanoislands produced on the surface of InP crystals by electroexplosion by I. Ya. Mittova; E. V. Tomina; A. A. Lapenko; B. V. Sladkopevtsev (383-388).
We report the deposition of chemostimulator nanoislands on the surface of indium phosphide by an electroexplosion process and the effect of experimental conditions (ambient composition, pressure, and source-substrate distance) on their size distribution and surface density. Vanadium oxide and vanadium islands are shown to have a catalytic effect on the surface oxidation of indium phosphide, ensuring one of the most effective interactions between a chemostimulator and a III–V semiconductor in an oxidizing atmosphere.

Morphology and optical properties of Sb2O3 by A. E. Panasenko; L. A. Zemnukhova; N. N. Barinov (389-392).
The chemical and phase compositions of antimony(III) oxide samples prepared under various conditions have been determined. The size and shape of their particles have been assessed by scanning electron microscopy, and the effect of UV irradiation on their diffuse reflectance spectra has been studied. The results are used to determine the whiteness index, integrated reflectance, and lightfastness of the samples.

The effect of high-energy mechanical processing on the adsorption behavior of the hydrophilic polymer ethyl hydroxyethyl cellulose (EHEC) on the surface of the inorganic pigments TiO2 and Fe2O3 has been studied by IR spectroscopy. High-energy processing of aqueous disperse systems of TiO2 and Fe2O3 activates the surface of the inorganic oxides and promotes polymer adsorption. We present the first evidence that the interaction of EHEC with oxide surfaces is accompanied by conformational changes in the adsorbed EHEC molecules. The conformational transitions depend on the lattice parameters of the inorganic oxides and lead to the formation of special adsorbed solvated EHEC layers, which determine the sedimentation stability of the disperse system.

Preparation of Er3+:YAlO3/ZnO coating compound by sol-gel method and photocatalytic degradation of organic dyes under sun light irradiation by Jun Wang; Jia Li; Yingpeng Xie; Liqun Zhang; Guangxi Han; Ying Li; Rui Xu; Xiangdong Zhang (399-404).
In this work, the Er3+:YAlO3, as upconversion luminescence agent, was prepared and coated by ZnO film through sol-gel technique and the Er3+:YAlO3/ZnO coating compound, a novel photocatalyst, with high activity under sun light irradiation was subsequently prepared. The Er3+:YAlO3 and Er3+:YAlO3/ZnO were characterized by XRD. The activity of Er3+:YAlO3/ZnO was tested by photocatalytic degradation of acid red B in aqueous solution. The experimental results proved that the Er3+:YAlO3/ZnO was able to decompose the acid red B efficiently, and it is promising to use the idea to develop new photocatalyst with high activity for degradation under sun light irradiation.

The formation of nanocrystalline calcium carbonate phosphates doped with Fe2+, Mg2, Zn2+, K+, Si4+, and Mn2+ has been studied by X-ray diffraction, IR spectroscopy, differential thermal analysis, and energy dispersive X-ray fluorescence analysis. The results indicate that the synthesis involves the formation of hydroxy carbonate complexes from the three calcium carbonate polymorphs (calcite, vaterite, and aragonite) in a solution of ammonium chloride and ammonium carbonate, followed by reaction with orthophosphoric acid. This ensures the preparation of a bioactive material based on chlorophosphates, octacalcium hydrogen phosphate, and calcium chloride hydroxide phosphates containing cation vacancies. Particle-size analysis data show that the materials contain nanoparticles down to 10 nm in size. Heat treatment of the doped calcium carbonate phosphates produces calcium hydroxyapatite containing cation vacancies, which can be used as a bioactive ceramic.

We have synthesized materials based on a silver titanium phosphate with partial substitution of tri-, tetra-, or pentavalent cations for titanium: Ag1±x Ti2−x M x (PO4)3 (M = Nb5+, Ga3+) and AgTi2−x Zr x (PO4)3. The materials have been characterized by X-ray diffraction and impedance spectroscopy and have been shown to have small thermal expansion coefficients. Their ionic conductivity has been determined. Silver ions in these materials are difficult to replace with protons.

Periodic micro- and nanostructures in LiNbO3〈Gd〉 single crystals grown under unsteady-state conditions by M. N. Palatnikov; O. B. Shcherbina; V. V. Efremov; N. V. Sidorov; V. T. Kalinnikov (418-423).
Gd-doped lithium niobate single crystals having a regular domain structure with a period from 100 to 1 μm have been grown under highly unsteady thermal conditions. Examination by atomic force microscopy shows that such lithium niobate single crystals contain periodic nanostructures with a period from 10 to 100 nm in the region of regular domain structures. Raman scattering data suggest that the cation sublattice of the lithium niobate crystals contains a superstructural sublattice of defect clusters with a step of 1–2 nm. We conclude that lanthanide-doped lithium niobate single crystals contain periodic fractal structures in a range of length scales, from ≃ 1 nm to 100 μm.

Magnetic properties of Bi(Fe1 − x M x )O3 (M = Mn, Ti) by I. O. Troyanchuk; A. N. Chobot; O. S. Mantytskaya; N. V. Tereshko (424-428).
The magnetic properties of Bi(Fe1 − x M x )O3(M = Mn, Ti) solid solutions have been studied in magnetic fields of up to 11.2 × 103 kA/m, and the composition stability range of the R3c ferroelectric phase has been determined. The results indicate that partial Ti4+ substitution for Fe3+ leads to a transition from a modulated antiferromagnetic state to a homogeneous weakly ferromagnetic ferroelectric state (x = 0.08), whereas the Bi(Fe 1−x 3+ Mn x 3+ )O3 solid solutions do not exhibit weak ferromagnetism. Charge compensation in is assumed to be ensured by cation vacancies.

Properties of Mg(Fe1 − x Ga x )2O4 + δ solid solutions in stable and metastable states by G. D. Nipan; V. A. Ketsko; A. I. Stognij; A. V. Trukhanov; T. N. Kol’tsova; M. A. Kop’eva; L. V. Elesina; N. T. Kuznetsov (429-433).
Using pyrohydrolytic synthesis, we have obtained a continuous series of Mg(Fe1 − x Ga x )2O4 + δ solid solutions, as checked by X-ray diffraction. The magnetization and coercivity of the samples have been determined from field dependences in applied magnetic fields of ±5 T, and their conductivity has been assessed using current-voltage measurements at 300 K in electric fields from −200 to +200 V. The effective band gap of the solid solutions has been evaluated from their absorption spectra obtained by diffuse reflectance measurements. The optimal composition for spintronic applications is Mg(Fe0.8Ga0.2)2O4 + δ.

Synthesis of nanocomposites based on MO-Bi2O3-B2O3 (M = Ca, Sr, Ba) glasses by A. V. Egorysheva; V. D. Volodin; V. M. Skorikov; G. Yu. Yurkov; N. I. Sorokin (434-438).
This work examines the effect of KBF4 additions on the crystallization behavior of glasses based on the multicomponent systems MO-Bi2O3-B2O3 with M = Ca, Sr, and Ba. The glass-ceramic composites obtained contain a δ-Bi2O3-based crystalline phase with a crystallite size of ≃7 nm, evenly distributed over the glass matrix. The 400°C electrical conductivity of the nanocomposites reaches 2 × 10−4 S/cm, and the activation energy is 1.1 eV, typical of anion conduction. These values are comparable to those reported for δ-Bi2O3 ceramics.

Fabrication of heavily Er2O3 doped aluminophosphosilicate glass fibers by A. N. Abramov; M. M. Bubnov; N. N. Vechkanov; A. N. Guryanov; K. V. Zotov; D. S. Lipatov; M. E. Likhachev; M. V. Yashkov (439-444).
This work examines vapor-phase doping of aluminophosphosilicate (APS) glasses with erbium oxide using Er(dpm)3 (erbium dipivaloylmethanate) as a metalorganic precursor. We describe two vapor-phase processes for Er2O3 doping of APS glasses for fiber cores. In one of them, a standard MCVD procedure, all the oxides of the glass core are deposited simultaneously. With this procedure, the erbium content of the APS glasses does not exceed 1 wt % because of the reaction of AlCl3 with POCl3 and Er(dpm)3. In the other procedure, a porous Al2O3-P2O5-SiO2 layer is infiltrated with Er2O3 from the vapor phase. Owing to the separation of the reactant flows, this procedure ensures considerably higher rare-earth doping levels in the APS glasses, up to several weight percent.

Corundum/lanthanum hexaaluminate/alumina nanofiber ceramic composite by B. N. Dudkin; A. Yu. Bugaeva; G. G. Zainullin; V. N. Filippov (445-448).
We describe a corundum-matrix ceramic composite loaded with layered lanthanum hexaaluminate microparticles and reinforced with alumina nanofibers. The components of the composite are prepared by sol-gel processing. Scanning electron microscopy results indicate that the microparticles and nanofibers are uniformly distributed over the matrix. Surface-modified alumina nanofibers are shown to have the best effect on the strength of the matrix.