X-ray Diffraction Patterns Of ZnO Research Articles

Intrinsic defect-induced magnetism and enhanced photocatalytic activity in Zn1−xZrxO (0.0 ≤ x ≤ 0.07) nanoparticles for spintronic device and photocatalytic application

In this study, ZnO nanoparticles were synthesized by sol-gel auto combustion technique with and without Zr4+ doping. The synthesized nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), selected area diffraction pattern (SAED), transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance spectroscopy (EPR). A rietveld refinement analysis was performed using fullprof software on the XRD patterns of ZnO and Zr4+ doped ZnO nanoparticles, analysis showed a hexagonal wurtzite structure with an average crystallite size between 19 and 15 nm. SEM were employed to examine the surface morphology. TEM used to determine the particle size and size distribution histogram. SAED pattern confirmed the single-crystalline wurtzite structure. The compositional stoichiometry was verified by energy dispersive spectroscopy (EDAX). The PL spectrum reveals UV emission at the near band edge, as well as defect-related blue and green emission. In the PL spectrum, the green emission of Zr doped ZnO nanoparticles correlates strongly with their magnetic properties.An oxygen vacancy defect was confirmed by EPR studies for Zr doped ZnO nanoparticles. Sample (x = 0.03) exhibited very high coercivity value due to higher oxygen vacancies (Vo). X-ray photoelectron spectroscopy showed the oxidation state of Zn and Zr4+ atoms exist as Zn2+ and Zr4+ in the ZnO structure respectively. A vibrating sample magnetometer (VSM) was used to quantify the magnetic properties. Field-dependent magnetization measurements show diamagnetic behavior for pristine and Zr (x = 0.01 mol) doped ZnO. However, other doped samples (x = 0.03, 0.05, and 0.07 mol) exhibited ferromagnetic behavior at room temperature due to intrinsic defects (Zni and Vo). A UV–visible absorption spectrum was used to determine the energy band gap. Compared with pristine ZnO nanoparticles, doped samples exhibit a redshift in absorption edge. In addition, the photocatalytic activity of synthesized samples was determined by degrading the dye methylene blue (M.B.) in the presence of sunlight. An extensive evaluation of the effect of Zr concentrations on photocatalytic degradation was conducted. Zr4+ doped ZnO nanoparticles exhibit emission peaks detected at 424, 446, and 573 nm. These emission peaks result from electron movement from the deep donor level, zinc interstitial (Zni), and oxygen vacancy(Vo), which ultimately leads to higher photocatalytic efficiency.

Facile synthesis of hierarchical ZnO structure for photocatalytic degradation of dimethyl phthalate

A facile co-precipitation method was employed to fabricate hierarchical ZnO structure and characterized by various analytical instruments. The images of ZnO from field-emission scanning electron microscopy exhibited spheroidal morphology which composed of numerous layers of nanosheets and formed a hierarchical structure. Energy dispersive X-ray spectrum validated the presence of Zn and O atoms and its purity. X-ray diffraction pattern of ZnO revealed the establishment of hexagonal wurtzite structure. Optical property analysis disclosed that the as-fabricated ZnO had strong absorbance of wavelength from 350-410 nm with an absorption band edge of 367 nm. In this paper, the photocatalytic activity of hierarchical ZnO structure was confirmed by degradation of endocrine disrupting chemical, namely dimethyl phthalate under UV lamp irradiation. The photodegradation of dimethyl phthalate in aqueous solution over as-fabricated ZnO reached 55.9% after 60 min irradiation. The photocatalytic degradation of DMP obeyed the pseudo first-order kinetic reaction with a rate constant of 0.0166 min−1.

Structural, morphological, antimicrobial, and cytotoxicity study of spindle-shaped ZnO submicron particles for potential biomedical applications

In the present study, spindle-shaped ZnO submicron particles were synthesized by hydrothermal method. The single-phase X-ray diffraction pattern of ZnO revealed a hexagonal wurtzite structure and the crystallite size of 25 nm was obtained by analyzing x-ray diffraction pattern. The field emission-scanning electron microscopy and transmission electron microscopy analysis revealed the spindle-shaped morphology of ZnO powder having a random orientation with 160 nm average particle size. The elemental dispersive spectra and elemental mapping quantize only two elements Zn and O, confirming the ZnO powder. The fourier transform infra-red spectroscopy revealed the existence of ZnO and OH groups in ZnO. The biological studies were performed to investigate the cytotoxic and anti-microbial activities of ZnO submicron particles The spindle-shaped ZnO submicron particles did not alter the viability of human PBMCs reflecting the biocompatible nature of ZnO submicron particles and the material is investigated as generally recognized as safe (GARS). The ZnO particles showed cytotoxicity against human liver cancer (HepG2) and breast cancer (MCF-7) cell lines.These ZnO particles (submicron) also showed significant anti-microbial activity against gram-negative (E. coli) and gram-positive (S. aureus) bacteria. The cumulative data present biocompatible spindle-shaped ZnO particles with anti-microbial and cytotoxic properties, suggesting these submicron particles as a safe candidate for biomedical applications.

Modifications in structure, surface morphology, optical and electrical properties of ZnO thin films with low boron doping

Boron doped zinc oxide (ZnO:B) thin films with low B concentration, varied between 0.50 and 1.50 atomic percentages (at%) are prepared at substrate temperatures (TS) between 300 and 450 °C using spray pyrolysis technique. Polycrystalline wurtzite structure is observed in the X-ray diffraction patterns of ZnO:B thin films, where (002) is the predominant peak. Texture coefficient corresponding to (002) peak increases with B concentration from 0.50 to 1.00 at%. Crystallite size is found between 22 and 64 nm. Nanofibrous surface morphology is observed in the field emission scanning electron microscopic images of ZnO:B thin films. The average nanofiber thickness value varies from 198 to 498 nm. Atomic force microscopic images show the nanotip-like topology of ZnO:B thin films. The average surface roughnesses of the films are found in the range of 2.99–12.45 nm. ZnO:B thin films are found to be highly transparent between visible to near infrared region of the electromagnetic spectrum. The highest transmittance of 87% is noticed for the 1.00 at% ZnO:B thin film prepared at the TS of 450 °C. Optical band gaps of ZnO:B thin films vary between 3.15 and 3.31 eV. 1.00 at% ZnO:B thin films prepared at various TS show lower values of the band gap, refractive index and extinction coefficient at the photon wavelength of 750 nm. Electrical resistivity of ZnO:B thin films are found to be between 0.25 × 104 and 1.39 × 104 Ω m. 1.00 at% ZnO:B thin films prepared at various TS show less electrical resistivity. Arrhenius plots of ZnO:B thin films prepared at various TS show two conduction regions and activation energies of ZnO:B thin films are higher for the films deposited at lower TS. ZnO:B thin films show n-type conductivity and carrier concentration increases with the increase of B concentration.

Electronic and Magnetic Field Dependent Dielectric Properties of Zn0.95Fe0.05O

We report a magneto-dielectric effect in Zn0.95Fe0.05O, which was synthesized by the microwave-assisted combustion method. The x-ray diffraction (XRD) pattern of Zn0.95Fe0.05O shows the shift in peaks towards lower theta values in comparison to the XRD pattern of ZnO. Rietveld analysis of XRD data shows the presence of 99.29% of Zn0.95Fe0.05O along with 0.71% ZnFe2O4 in Fe doped ZnO. Infrared spectroscopic studies show the shift in absorption peak towards lower wavenumber with Fe doping at Zn sites in ZnO. Soft x-ray absorption spectroscopy studies show the mixed valence states of Fe (Fe+2 and Fe+3). Magnetic properties show paramagnetic behaviour of Zn0.95Fe0.05O at room temperature. The magneto-dielectric effect is originated in Zn0.95Fe0.05O due to the decrease in space polarization effect in the presence of Fe+2 at the Zn site in a magnetic field. The dielectric constant er is found to be 4.09 × 105 in 1 Hz and 11.65 in 1 MHz frequency in the absence of a magnetic field for Zn0.95Fe0.05O. The dielectric constant er is found to be 2.88 × 105 in 1 Hz and 10.37 in 1 MHz frequency in the 500 Gauss magnetic field for Zn0.95Fe0.05O. Magnetic field sensitivity is found as ~ 16% in the 15 kG magnetic field and 30 MHz frequency for Zn0.95Fe0.05O.

Review on X-ray diffraction patterns of ZnO

Review on X-ray diffraction patterns of ZnO

Shock-wave synthesis of high-density modifications of zinc oxide (review)

The results of x-ray diffraction studies of preserved zincite samples subjected to dynamic compression (28 GPa) and the powder patterns of hydrothermally grown ZnO crystals are presented. Three new modifications have been synthesized: ZnO(I, II, III). The x-ray diffraction pattern of ZnO(I) is indexed in the hexagonal unit cell with a = 4.121(2) A, c = 15.114(5) A, V = 222.3 A3, Z = 12, ρcalc = 7.293 g/cm3, Fedorov group P63/mmc. The x-ray diffraction data for ZnO(II) are indexed in an orthorhombic subcell with a = 5.997(2) A, b = 5.267(1) A, c = 2.369(1) A, V = 74.8 A3, Z = 4, ρcalc = 7.222 g/cm3. The x-ray diffraction pattern of ZnO(III) is indexed in the primitive monoclinic cell with a = 7.931(8) A, b = 7.911(4) A, c = 2.995(1) A, β = 91.07(4)°, V = 188 A3, Z = 8, ρcalc = 5.749 g/cm3