Scholarlink

<p>Magnesium doped nano zinc aluminate spinel samples (Zn<sub>1-x</sub>Mg<sub>x</sub>Al<sub>2</sub>O<sub>4</sub>; x = 0.0, 0.1, 0.3, 0.5, 0.7 and 1) were fabricated using the solid-state reaction approach. The synchrotron X-ray diffraction technique was utilized with Rietveld refinement to find out the percentage of formed phases, crystallite size, lattice parameters and cation distribution. For all analyzed samples, in addition to the principal phase ZnAl<sub>2</sub>O<sub>4</sub>, a minor proportion of the ZnO phase was identified. At elevated concentrations of Mg, an additional phase, MgO, was discerned. The crystallite dimensions decreased as the Mg content increased, transitioning from nanoscale (11.9&#xa0;nm) to quantum dot scale (2.1&#xa0;nm). The ZnAl<sub>2</sub>O<sub>4</sub> sample exhibited a partially inverse cation distribution, which was further augmented by Mg doping. For x ≤ 0.3, Mg ions were located at the octahedral sites; however, for x &gt; 0.3, Mg ions were found to be distributed between octahedral and tetrahedral positions. Excluding the sample with x = 0.1, the absorption of all doped samples was enhanced, particularly within the range of 200–370&#xa0;nm, consistently increasing with Mg content, reaching maximum for x = 0.7 before exhibiting a slight reduction for x = 1.0. The pure ZnAl<sub>2</sub>O<sub>4</sub> sample revealed two energy gaps: 3.27&#xa0;eV corresponding to the minor ZnO phase and 4.23&#xa0;eV for ZnAl<sub>2</sub>O<sub>4</sub>, which changed upon Mg doping. The sample with x = 0.1 exhibited the highest refractive index values and the lowest absorption within the UV–visible spectrum, rendering it suitable for various optical applications. Except for x = 0.1, the optical conductivity in the UV–visible range increased with Mg doping, but the enhancement was irregular with respect to wavelength. The sample with Mg content x = 0.1 displayed significantly improved nonlinear optical (NLO) properties in the 200–700&#xa0;nm range, whereas for λ &gt; 700&#xa0;nm, the sample with x = 1 achieved the utmost NLO values, which nominates these samples for a variety of nonlinear optical and photonic applications. The photoluminescence (PL) spectra were fully investigated under two excitation wavelengths λ<sub>exc</sub> = 280 and 450&#xa0;nm to trace the potential defects that may be present in obtained samples.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Structural and optical investigations of magnesium doped nano zinc aluminate spinel samples

  • 期刊论文

  • 发表日期：

    2025年7月16日

查看全文
  • Zein K. Heiba,
  • M. M. Ghannam,
  • Hadeer Mohamed Helal,
  • Essam E. Ali,
  • Ali Badawi,
  • Mohamed Bakr Mohamed

摘要

Magnesium doped nano zinc aluminate spinel samples (Zn1-xMgxAl2O4; x = 0.0, 0.1, 0.3, 0.5, 0.7 and 1) were fabricated using the solid-state reaction approach. The synchrotron X-ray diffraction technique was utilized with Rietveld refinement to find out the percentage of formed phases, crystallite size, lattice parameters and cation distribution. For all analyzed samples, in addition to the principal phase ZnAl2O4, a minor proportion of the ZnO phase was identified. At elevated concentrations of Mg, an additional phase, MgO, was discerned. The crystallite dimensions decreased as the Mg content increased, transitioning from nanoscale (11.9 nm) to quantum dot scale (2.1 nm). The ZnAl2O4 sample exhibited a partially inverse cation distribution, which was further augmented by Mg doping. For x ≤ 0.3, Mg ions were located at the octahedral sites; however, for x > 0.3, Mg ions were found to be distributed between octahedral and tetrahedral positions. Excluding the sample with x = 0.1, the absorption of all doped samples was enhanced, particularly within the range of 200–370 nm, consistently increasing with Mg content, reaching maximum for x = 0.7 before exhibiting a slight reduction for x = 1.0. The pure ZnAl2O4 sample revealed two energy gaps: 3.27 eV corresponding to the minor ZnO phase and 4.23 eV for ZnAl2O4, which changed upon Mg doping. The sample with x = 0.1 exhibited the highest refractive index values and the lowest absorption within the UV–visible spectrum, rendering it suitable for various optical applications. Except for x = 0.1, the optical conductivity in the UV–visible range increased with Mg doping, but the enhancement was irregular with respect to wavelength. The sample with Mg content x = 0.1 displayed significantly improved nonlinear optical (NLO) properties in the 200–700 nm range, whereas for λ > 700 nm, the sample with x = 1 achieved the utmost NLO values, which nominates these samples for a variety of nonlinear optical and photonic applications. The photoluminescence (PL) spectra were fully investigated under two excitation wavelengths λexc = 280 and 450 nm to trace the potential defects that may be present in obtained samples.