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The concept and theoretical basis of the three-component zone melting method is given for growing single crystals of semiconductor solid solutions using seeds from constituent components. In the Pfann approximation, the problem of the axial concentration distribution of components in Ge–Si single crystals grown at different values of the operating parameters such as the length of the melted zone and the composition of the initial macrohomogeneous rods of solid solutions is solved. Analysis of the obtained results determines the potentialities of the method and the optimal conditions for growing single crystals with given homogeneous and graded compositions in the entire continuous series of Ge–Si solid solutions. It is shown that the three-component zone-melting method is promising for the growth of single crystals of semiconductor solid solutions.

In this study one-pot synthesis of zinc-aluminum mixed oxide/polyvinyl alcohol (ZnAl mixed oxide/PVA) nanocomposite and its adsorption behavior for efficient removal of lead (II) ions from aqueous ...

Cobalt oxide nanoparticles were synthesized using a facile and convenient sonochemical method, followed by a calcination process. For the synthesis, cobalt nitrate, and sodium borohydride w...

Convenient and environmentally friendly synthesis of Co9S8/PVA, CoxSy/EG and CoxSy/3-MPA nanocomposites were carried out in the presence of ultrasonic irradiation by the liquid phase synthesis of the sonochemical method. For the synthesis, cobalt acetate tetrahydrate [Co(CH3COO)2·4H2O] and sodium sulfide (Na2S·9H2O) were used as a cobalt and sulfur precursor, respectively. Polyvinyl alcohol (PVA), ethylene glycol (EG) and 3-mercaptopropionic acid (3-MPA) were used as a capping agent and surfactant. The structural, optical properties and morphology of nanocomposites were characterized using X-ray diffractometer (XRD), Ultraviolet/Visible Spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The optical band gap of Co9S8/PVA is 1.81 eV and for CoxSy/EG is 2.42 eV, where the direct band gap of bulk cobalt sulfide is (0.78–0.9 eV). The wide band gap indicates that synthesised nanocomposites can be used in the fabrication of optical and photonic devices. The growth mechanisms of the Co9S8, CoS2 and Co3S4 nanoparticles were discussed by the reactions. The effects of sonication time and annealing temperature on the properties of the nanoparticles have been studied in detail.

β-NiS nanoparticles (NPs) grown through SILAR technique into functionalized nitrile butadiene rubber (FNBR) were used for the synthesis of CuS-NiS/FNBR and Cu1.8S-Ni3S4/FNBR nanocomposites (NCs). The evaluated band gap decreased from 2.8 eV to 2.3 eV and 2.21 eV using 0.25 M of CuSO4 × 5H2O and 0.5 M of CuCl2 × 2H2O, respectively. The effect of copper precursors and concentration of Cu2+ ions on the particle size, chemical composition of NCs and properties has been discussed in detail. Different structural phases of nickel sulfide and copper sulfide were obtained using NiS/FNBR nanocomposites as a precursor for ion exchange reaction by Cu2+ ions. Properties of CuxS-NiySz/FNBR and CuS-NiySz/FNBR nanocomposites obtained after modification have been studied and compared with initial nanocomposite of NiS/FNBR. The average particle size increased from 8.5 nm to 13.5 nm and 15 nm after ion exchange modification. By EPR spectrum the superhyperfine splitting is seen in the spectrum of CuS-NiySz/FNBR, ACu = 107.3 G. In perpendicular section the bandwidth of the spectrum (ΔH) is equal to 930 G. Recording to SEM images very clearly imaged spherical nanoparticles have been observed.

Here is reported the synthesis of o-phenylenediamine functionalized graphite (OPDFG) using the phosphorus trichloride surface modified graphite (PCl3-SMG) and the o-phenylenediamine (OPD). PCl3-SMG was obtained via chlorophosphorylation of graphite for the study. PCl3-SMG and OPDFG were analyzed using ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD) and Scanning Electron Microscope (SEM). UV-Vis analysis shows that OPDFG have higher absorbance than graphite and PCl3-SMG. According to FTIR analysis, PCl3-SMG has –PCl2 functional groups, which shows that PCl3 reacts with sp2 C-H groups on graphite's edge planes during the formation of PCl3-SMG. Synthesis of OPDFG can be explained by a replacement reaction of amine groups of OPD with –PCl2 groups. XRD data show that after modification of graphite with PCl3 and after amine treatment of PCl3-SMG, crystallite sizes of PCl3-SMG and OPDFG decrease. SEM analysis shows that both PCl3-S...

Ni/NiO nanochains were successfully synthesized by a facile and environmentally friendly chemical reduction method under different magnetic fields, followed by thermal oxidation at high temperatures. For the synthesis of Ni nanoparticles, hydrazine hydrate and sodium borohydride were used as reducing agents. In order to determine the size, structure, optical properties and morphology, the obtained products were characterized by X-ray diffraction (XRD), ultraviolet–visible Spectroscopy (UV–Vis), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Additionally, the effect of reaction time, different magnetic field intensity and oxidation temperature on the size and morphology of synthesized nanoparticles was investigated in detail. The average size of as-prepared Ni nanoparticles in nanochain decreases with increasing magnetic force. After oxidation of samples at 600 °C, the size of NiO formed on the surface of Ni nanochains increases with increasing magnetic force. This is related to the faster oxidation of small particles due to their high surface energy. According to TEM measurements, the average diameter of Ni/NiO nanochains (synthesized at 25 mT after oxidized at 600 °C) is in the range of 97–133 nm and spherical particles are assembled in the form of a chain-like, which confirms SEM results.

Mathematical modeling of the distribution of Ga and Sb impurities in homogeneous (with respect to the content of the main components) single crystals of Ge–Si alloys, grown by double feeding of the melt, has been performed in the Pfann approximation. It is shown that the axial gradient of impurity concentration in Ge–Si crystals can be controlled in wide limits by changing the ratio of crystallization rate and the rates of feeding of the melt by silicon and germanium rods. The conditions for growing alloy single crystals, homogeneous both with respect to the content of the main components and to the impurity concentration distribution, have been determined.

Nickel sulfide nanostructures have been successfully prepared with two different sulfur sources like thiourea (S C(NH 2 ) 2 ) and sodium sulfide by the successive ionic layer adsorption and reaction (SILAR) method. The functionalized nitrile-butadiene rubber (F-NBR) was used as stabilizing agent for formation of nickel sulfide semiconductor nanoparticles. The nanoparticle sizes correspond to 8.5 nm and 7 nm using thiourea and sodium sulfide respectively. The as-synthesized NiS and Ni 3 S 4 nanostructures were characterized by XRD, SEM, EDX, UV–vis and FTIR spectroscopy methods. A systematic investigation of the final end products has been done to elucidate the formation mechanism at different experimental parameters. Using thiourea the optical band gap of NiS for 4, 6 and 8 cycles were determined to be 3.12, 2.93 and 2.81 eV, respectively. The optical band gap of Ni 3 S 4 for 6 and 8 cycles were determined to be 2.8 and 2.15 eV, respectively.

The synthesis of nanoparticles by microorganisms is environmentally safe method. The silver nanoparticles produced by fungi is complex material having different size, shape and other properties depending on the producer. İt is necessary to study new microbial strains to synthesize silver nanoparticles with important properties. The synthesis of different stable silver nanoparticles by the mold fungi was investigated in this work. To achieve this goal different strains (isolates) of Aspergillus niger were used. The most intensive formation of nanoparticles was observed in strains Aspergillus niger BDU-A4, BDU-K8, BDU-UB1 and BDU-UB5.While examining nanoparticles the following analysis methods were used: UV-Visible Spectroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy. Electron microscopic examination showed that the shape, size and nature of nanoparticles’ clusters were dependent on fungal strains. The shape of nanoparticles is usually circular but it may be oval like in case of nanoclusters consisting of a few spherical nanoparticles. Their size varies from 20 to 100 nm.The formation of free ellipsoidal shape nanoparticles was observed at strain of Aspergillus niger BDU-K8, that varies in the range 62,9 - 68,4 nm.