Synthesis And Studied Structural and Morphological Properties of 1-Dimensional Zno-Ag2O-Ag Nanowire

1-dimensional zinc oxide (ZnO) - silver oxide (Ag2O) – silver (Ag) nanowire was prepared using a simple and inexpensive bottom-up chemical method. X-ray diffraction (XRD) results showed the presence of diffraction peaks of ZnO and Ag2O with hexagonal wurtzite phase of ZnO. Energy Dispersive X-ray (EDX) results showed the presence of energy peaks of Zinc (Zn), Silver (Ag), and Oxygen (O) elements. Filed Emission Scanning Electron Microscopy (FE-SEM) results showed that the surface morphology is nanowire (1-dimensional structure) with shapes similar to hedgehog spines and have small nanoscale diameters. The present work represents a promising step in the preparation of a 1-dimensional nanowire.

First-principles calculations of elastic and optical properties of Aluminum Nitride (AlN) in cubic and hexagonal phase

Investigation of elastic and optical properties of AlN in rock salt, zinc blende, and wurtzite phase is done under the framework of Density Functional Theory (DFT) with modified Becke Johnson Generalised Gradient Approximation (mBJ-GGA) as exchange-correlation functional. Elastic properties conclude the bonding nature of the AlN in the rock salt phase is covalent and stiffest, while the bonding nature in the zinc blende and wurtzite phase is found to be ionic and less stiff. The ratio of bulk modulus to shear modulus indicates AlN is brittle in all three phases. The calculated Debye temperature in all three phases is in good agreement with the available theoretical and experimental works. The optical properties calculation shows the AlN is transparent in the low energy range and it has the metallic behavior in the energy range 7.5eV to 10 eV. At the same time, the compound loses its transparency at the high energy range. Our calculated value of the refractive index of AlN in the rock salt, zinc blende, and wurtzite phases is in good agreement with the available experimental and theoretical works.

Quantitative analysis of metastable wurtzite phase into the self-catalyzed GaP NWs

In this letter, we report the growth of the self-catalyzed GaP nanowires with a high concentration of wurtzite phase by molecular beam epitaxy. Formation of rotational twins and wurtzite polymorph in vertical nanowires was observed by the developed a complex approach based on the transmission electron microscopy and X-ray diffraction method. Microstructural analysis performed by high resolution transmission electron microscopy and micro-Raman spectroscopy gives us insights on the nanowire formation mechanism and vibrational properties of nanowires with mixed crystal phase. We obtained wurtzite polytype segments with thicknesses lying in the range from several tens up to 500 nm. The results of the work open new perspectives for high phase purity phosphide NWs synthesis and its fast investigation with XRD technique using a laboratory X-Ray source.

Two-dimensional ZnS@N-doped carbon nanoplates for complete lithium ion batteries

Metal sulfides are attractive anode materials for lithium ion batteries due to the high specific capacities and better electrochemical kinetics comparing to their oxide counterparts. In this paper, novel monocrystalline wurtzite ZnS@N-doped carbon (ZnS@N-C) nanoplates, whose morphology and phase are different from the common ZnS particles with cubic phase, are successfully synthesized. The ZnS@N-C nanoplates exhibit good cycling stability with a high reversible specific capacity of 536.8 mAh∙g-1 after 500 cycles at a current density of 500 mA∙g-1, which is superior to the pure ZnS nanoplates, illustrating the obvious effect of the N-doped carbon coating for alleviating volume change of the ZnS nanoplates and enhancing the electronic conductivity during charge/discharge processes. Furthermore, it is revealed that the ZnS single crystals with wurtzite phase in the ZnS@N-C nanoplates are transformed to the polycrystalline cubic phase ZnS after charge/discharge processes. In particular, the ZnS@N-C nanoplates are combined with the commercial LiNi0.6Co0.2Mn0.2O2 cathode to fabricate a new type of LiNi0.6Co0.2Mn0.2O2/ZnS@N-C complete battery, which exhibits good cycling stability up to 120 cycles at 1C rate after the prelithiation treatment on the ZnS@N-C anode, highlighting the potential of the ZnS@N-C nanoplates as an anode material for lithium ion battery.

Optical Properties of Magnesium-Zinc Oxide for Thin Film Photovoltaics

Motivated by their utility in CdTe-based thin film photovoltaics (PV) devices, an investigation of thin films of the magnesium-zinc oxide (MgxZn1−xO or MZO) alloy system was undertaken applying spectroscopic ellipsometry (SE). Dominant wurtzite phase MZO thin films with Mg contents in the range 0 ≤ x ≤ 0.42 were deposited on room temperature soda lime glass (SLG) substrates by magnetron co-sputtering of MgO and ZnO targets followed by annealing. The complex dielectric functions ε of these films were determined and parameterized over the photon energy range from 0.73 to 6.5 eV using an analytical model consisting of two critical point (CP) oscillators. The CP parameters in this model are expressed as polynomial functions of the best fitting lowest CP energy or bandgap E0 = Eg, which in turn is a quadratic function of x. As functions of x, both the lowest energy CP broadening and the Urbach parameter show minima for x ~ 0.3, which corresponds to a bandgap of 3.65 eV. As a result, it is concluded that for this composition and bandgap, the MZO exhibits either a minimum concentration of defects in the bulk of the crystallites or a maximum in the grain size, an observation consistent with measured X-ray diffraction line broadenings. The parametric expression for ε developed here is expected to be useful in future mapping and through-the-glass SE analyses of partial and complete PV device structures incorporating MZO.

Annealing Temperature Dependence of Various Properties of ZnO Nanoparticles Investigated with Soft XAS

In this paper, structural, optical and electronic properties of ZnO nanoparticles were investigated with the variation in the annealing temperature. X-ray diffraction, High-Resolution Transmission Electron Spectroscopy, Absorption spectroscopy, Raman Spectroscopy and Soft X-ray spectroscopy techniques were invoked to investigate and gauge the effect of annealing temperature on these properties. Intact Hexagonal Wurtzite phase of the nanoparticles with increasing crystallinity and spherical shape with particle size between 20[Formula: see text]nm and 23[Formula: see text]nm [using both X-ray Diffractometer (XRD) and High-resolution Transmission of electron microscopy (HRTEM)], blue shift of absorption peak from 372[Formula: see text]nm to 366[Formula: see text]nm and Optical Band Gap from 3.24[Formula: see text]eV to 3.17[Formula: see text]eV (UV-Vis-NIR), narrowing of [Formula: see text] mode in Raman Spectra; all indicated enhanced crystallinity with increased annealing temperature. Effects produced by the sole variable such as annealing temperature on the indicative parameters in a definite order catapult the annealing conditions as a significant candidate for customized properties. To have a deeper insight at the electronic levels, Synchrotron-based X-ray absorption spectroscopic studies of ZnO nanoparticles were undertaken. The analysis of Soft XAS spectra showed the change in number of O 2[Formula: see text] and Zn 4[Formula: see text] unoccupied states with increasing particle size and crystallinity of ZnO nanoparticles for varying annealing temperature.

Synthesis of photocatalytic zinc oxide nanoflowers using Peltophorum pterocarpum pod extract and their characterization

Zinc oxide nanoflowers (ZnONFs) were prepared by employing the pod extract of Peltophorum pterocarpum as a green resource and characterized by various methods. UV–vis spectrum displayed a peak at 361 nm which confirmed the formation of ZnO nanoparticles. The optical band gap was calculated as 3.43 eV. FE-SEM images exposed the flower-like morphology and EDX portrayed strong signals for Zn and O. XRD studies substantiated signature peaks for the wurtzite phase of ZnONFs and the lattice parameters matched well with the literature. Mesoporous nature was confirmed by BET analysis which yielded a high specific surface area of 19.61 m2/g. FTIR bands at 420.48 and 462.92 cm−1affirmed the Zn and O bonding vibrations. The photocatalytic potential of the ZnONFs was successfully examined for the removal of methylene blue dye under natural solar light. The experimental data were fitted to Langmuir–Hinshelwood’s first-order equation and the kinetic constant was calculated as 0.0114 min–1.

ZnS Quantum Dot Based Acetone Sensor for Monitoring Health-Hazardous Gases in Indoor/Outdoor Environment

This study reports the ZnS quantum dots (QDs) synthesis by a hot-injection method for acetone gas sensing applications. The prepared ZnS QDs were characterized by X-ray diffraction (XRD) and transmission electron microscopy analysis. The XRD result confirms the successful formation of the wurtzite phase of ZnS, with a size of ~5 nm. Transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and fast Fourier transform (FFT) images reveal the synthesis of agglomerated ZnS QDs with different sizes, with lattice spacing (0.31 nm) corresponding to (111) lattice plane. The ZnS QDs sensor reveals a high sensitivity (92.4%) and fast response and recovery time (5.5 s and 6.7 s, respectively) for 100 ppm acetone at 175 °C. In addition, the ZnS QDs sensor elucidates high acetone selectivity of 91.1% as compared with other intrusive gases such as ammonia (16.0%), toluene (21.1%), ethanol (26.3%), butanol (11.2%), formaldehyde (9.6%), isopropanol (22.3%), and benzene (18.7%) for 100 ppm acetone concentration at 175 °C. Furthermore, it depicts outstanding stability (89.1%) during thirty days, with five day intervals, for 100 ppm at an operating temperature of 175 °C. In addition, the ZnS QDs acetone sensor elucidates a theoretical detection limit of ~1.2 ppm at 175 °C. Therefore, ZnS QDs can be a promising and quick traceable sensor nanomaterial for acetone sensing applications.