Characterizations of the prepared pseudo penta-glass system 60 PbO – (40-x) SiO₂ – x (0.1 Li₂O – 0.86 B₂O₃ – 0.04 Dy₂O₃) with 0 ≤ x ≤ 30 mol% were performed in terms of the ultrasonic and spectroscopic techniques. The increase of (0.1 Li₂O – 0.86 B₂O₃ – 0.04 Dy₂O₃) content causes borate structural variations such as the transformation of [BO₃] to [BO₄] structural units and enhancement of the compactness of the glasses. These physical parameters play an important role in modifying the mechanical and the optical properties of the lead silicate glasses. The improvement of the mechanical properties is indicated from the increment of the density, the ultrasonic velocities, the elastic moduli (experimentally determined and theoretically computed) and the glass transition temperature. The borate structural variations along with the presence of Dy₂O₃ decrease both the UV transmission and the optical energy gap, increase the refractive index and created several transitions at different wavelengths.

The structural, electrical, optical, and magnetic properties of Zn_0.95M_0.05O samples (M = Zn, Ni, Cu, Fe, and Mn) are investigated. X-ray diffraction pattern revealed pure hexagonal wurtzite structure for all samples with an (210) additional peak formed only at 2 ~ 43.5° for Ni sample. The average crystalline diameter decreased from 20 nm for ZnO to 11.35 nm by the dopants, while the lattice and U parameters are nearly unchanged. Furthermore, the nonlinear coefficient and breakdown field are increased from 370.37 and 21.91 for ZnO up to 2291.67 and 55.96 by the dopants. The electrical conductivity of the upturn region is also increased by the dopants as compared to ZnO. There are two different values of the energy bandgap for each sample. The first gap is called fundamental gap E_gh and its value above 3 eV, while the second gap is called optical gap E_gL and its value below 2.6 eV. On the other hand, the UV band edges of photoluminescence intensity are 394, 402, 372, 390, and 404 nm, for Zn, Ni, Cu, Fe, and Mn samples. The Green shift is only recorded for Cu sample at 562 nm corresponding to 2.21 eV energy gap. The exciton energy, loss factor tan δ, and (N/m*) parameter are generally decreased by the dopants and follow the order Ni, Cu, Fe, Mn, and Zn, while lattice dielectric constant and inter-atomic distance are increased and follow the orders Zn, Mn, Fe, Cu, and Ni, and Zn, Ni, Cu, Mn, and Fe, respectively. Magnetization curves revealed clear room temperature ferromagnetism (RTFM) for Mn, Ni, and Fe samples, while they are showed weakly RTFM for Zn and Cu samples. Saturated magnetization M_s, remnant magnetization M_r, magnetization width, magnetic moment, coercivity of the field, and magneto-crystalline anisotropy factor are also affected by the dopants. Our results are discussed in terms of oxygen vacancies, valance state, and recombination of carriers, exhibited by the dopants to ZnO, rather than individual RTFM.

Structural and Electrical Properties of ZnO Varistor with Different Particle Size for Initial Oxides Materials - NASA/ADS Now on home page ads icon ads Enable full ADS view NASA/ADS Structural and Electrical Properties of ZnO Varistor with Different Particle Size for Initial Oxides Materials Amin, Susan A. Abstract Publication: Nanoscale Reports Pub Date: April 2019 DOI: 10.26524/nr1923 Bibcode: 2019NanoR...2...20A full text sources Publisher | © The SAO/NASA Astrophysics Data System adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A NASA logo Smithsonian logo Resources About ADS ADS Help What's New Careers@ADS Social @adsabs ADS Blog Project Switch to full ADS Is ADS down? (or is it just me...) Smithsonian Institution Smithsonian Privacy Notice Smithsonian Terms of Use Smithsonian Astrophysical …

We report here the structure, electrical, optical and magnetic properties of Zn_1−xPr_xO nanoparticles with various x values (0.00 ≤ x ≤ 0.50). X-ray diffraction pattern revealed wurtzite structure for all samples with an additional unknown peak formed at 2Ɵ = 28° for Pr = 0.00, 0.05, 0.10 samples. The cell parameters and dislocation density are increased with increasing Pr up to 0.30, followed by a decrease at Pr = 0.50. While a little bit decrease in the average grain size and an increase in the ZnO bond length are obtained. The nonlinear coefficient β, breakdown field E_B and barrier voltage V_ab are gradually shifted to lower values as Pr increases. They are decreased from 31.3, 2333 V cm⁻¹ and 0.005 V for ZnO to 8.9, 750 V cm⁻¹ and 0.001 V for 0.50 of Pr. The electrical conductivity versus temperature shows two conduction mechanisms and it is generally increased by increasing Pr and temperature. The conduction mechanisms are obtained at a temperatures width of (300–540 K) and (540–620 K), respectively. The activation energy E_a is decreased from 0.42 eV to 0.13 eV by 0.50 of Pr in the first region, while it is increased from 0.42 eV to 0.93 eV in the second region. The optical band gap E_g and exaction photon energy E_ex are decreased by increasing Pr up to 0.50. They are decreased from 3.1 eV and 3.4 eV for ZnO to 1.62 eV and 2.79 eV by 0.50 of Pr, while Urbach energy E_u increased from 0.32 eV to 1.13 eV. Magnetization curves revealed room temperature ferromagnetism (RTFM) as Pr increases. The coercivity of the field H_c, saturated and remnant magnetization, magnetic moment are also increased by Pr up to 0.50. Our results are discussed in terms of oxygen vacancies, the density of states and local spin-polarized electrons exhibited by Pr as a dopant to ZnO.

Zn_1-x Co_x O (0≤ x≤ 0.10) nano-particles were fabricated successfully via ball milling procedure. The influence of [Co]/[Zn] on the properties of nano-particles was examined employing X-ray diffraction, the energy dispersion of the X-ray (EDX), Scan Electron Microscope (SEM), these measurements exhibit the growth hexagonal wurtzite crystal phase Zn_1-xCo_xO nano-particles with the successfully incorporation of Co⁺² ions in the ZnO lattice. The optical characterization investigated utilizing Ultraviolet-Visible (UV) absorption spectroscopy for Zn_1-xCo_xO nano-particles refers to a red-shift in the optical bandgap with increasing Co ion inside ZnO matrix, this result confirm the bandgap is considerably narrowed with increasing Co ratio. The measurements of magnetization applying vibrating sample magnetometer illustrated a hysteresis loop in Co-doped ZnO nano-particles. Thanks to the variation values of bandgap E_g^opt and magnetic measurements of ZnO nano-particles doped Co% plays a major role for selective coatings of optoelectronics; use as antireflective coating materials, and fabrication of optoelectronic devices.

Glasses of (Se₉₀Te₁₀)₉₅M₅ (where M = Zn and Bi) were prepared using a melt–quench procedure. These incorporated elements were chosen as examples of transition metals and basic metal groups, respectively. Thin films of these glasses at a thickness of 100 nm were evaporated onto cleaned glass substrates. Structural investigations were studied using XRD, SEM, and DSC. The glass transition, T_g, and Onset crystallization behavior of glasses, T_c of (Se₉₀Te₁₀)₉₅M₅ (M = Zn and Bi) alloys were analyzed using DSC at a heating rate of 15 K min⁻¹. XRD patterns confirmed the amorphous nature of the films. The absorption coefficient, α, and refractive index, n, were obtained for (Se₉₀Te₁₀)₉₅M₅ (M = Zn and Bi) films. The E_g values of Se₉₀Te₁₀ increase as dopant by Zn. Conversely, it decreases as dopant by Bi. Moreover, the optical constants of (Se₉₀Te₁₀)₉₅M₅ (M = Zn and Bi) films were estimated. The estimated results confirm the applicability of modifying samples to be used using in optoelectronics applications.

Initially, Sulfur (S) doping in Se₉₀Te₁₀ glassy alloy was utilized for clarifying the effects produced by minerals on its glass mesh and kinetic characteristics. The crystallization kinetics of bulk Se₉₀Te₁₀ and (Se₉₀Te₁₀)₉₅S₅ with different heating rates were analyzed by the differential scanning calorimetry. The processes of the alloy recrystallization after the thermal treatment were recognized by X-ray diffraction. The activation of energy, E_g, of glass transition crystallization, E_c, was utilized for determining various kinetic models. The analysis and experimental data revealed that E_g and E_C differ for the additive elements. The effective E_c of crystallization was calculated based on the Kissinger formula. Thus, the Sestak–Berggren model was used for characterizing the DSC crystallization information when it agreed to the experimental results. Consequently, it was found that the Johnson–Mehl–Avrami model can be applied at high heating rates.

The antimony tri-sulphide (Sb₂S₃) films were prepared by thermal evaporation technique. Four thicknesses (300, 521, 643 and 789 nm) were investigated. X-ray diffraction (XRD) analysis showed the amorphous structure of Sb₂S₃ films. Optical analyses revealed that Sb₂S₃ films exhibited optical energy gap between (1.98–1.16 eV) relaying on the film thickness. The films absorption coefficient was found to be higher than 2 × 10⁴ cm⁻¹(above its related optical energy gap) which makes these films reliable absorbers in photovoltaic applications. Optical constants were analyzed using Swanipole's method. The dark dc conductivity measurements of Sb₂S₃ thin films were conducted in the temperature range 298–503 K. The conduction mechanize was analyzed via Mott's variable -range hopping in three dimensions model. The correlated conductivity mechanize with increasing film thickness changed from extended states to localized states. The results revealed that both optical gap and activation energy decreased as the film thickness enhanced.

Glasses of (Se₉₀Te₁₀)₉₅M₅ (M = In, Sb, and S) are set by melt-quench procedure. The incorporated elements were selected as examples from basic metal, semimetal, and nonmetal groups, respectively. Films of these glasses were evaporated onto glass substrates. The nature of the films was affirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The amorphous nature of the prepared films was confirmed by XRD measurements. Absorption coefficient, α, and refractive index, n, were estimated for all (Se₉₀Te₁₀)₉₅M₅ (M = In, Sb, and S) films. It is found that the optical band gap E_g decreases in the basic metal and semimetal groups, whereas it increases in the nonmetal group. The optical constants were estimated according to the single-oscillator model. The estimated results confirmed that the modified samples can be employed in the optoelectronic applications.