scholarly journals Effect of Nb Doping on Morphology, Optical and Magnetic Behaviors of Ultrasonically Grown Zno Nanostructures

2017 ◽  
Vol 14 (2) ◽  
pp. 79-88 ◽  
Author(s):  
U. PAL ◽  
N. MORALES-FLORES ◽  
E. RUBIO-ROSAS

ZnO nanostructures containing doped with different atom % of Nb are fabricated through ultrasound assisted hydrolysis in water. Effects of Nd incorporation on the structure, morphology, defect structure, optical, and magnetic behaviors of the nanostructures have been studied utilizing X-ray diffraction, scanning electron microscopy, photoluminescence spectroscopy and magnetometry. We demonstrate that while Nb incorporation in ZnO nanostructures drastically modify their morphology and crystallinity, it does not affect the band gap energy of of ZnO significantly. While Nb incorporation in small concentration creates higher oxygen vacancy related defects in ZnO nanostructures, which are responsible for their visible emissions, incorporation of Nb in higher concentration reduces those defect structures from the band gap of the nanostructures. While oxygen vacancies have been frequently associated to the ferromagnetic behavior of ZnO nanostructures, our results indicate that a mere presence of oxygen vacancy in Nb-doped ZnO nanostructure does not guaranty their ferromagnetic behavior.

2021 ◽  
Vol 317 ◽  
pp. 95-99
Author(s):  
Muhammad Noorazlan Abd Azis ◽  
Halimah Mohamed Kamari ◽  
Suriani Abu Bakar ◽  
Azlina Yahya ◽  
Umar Saad Aliyu

Borotellurite glass had been widely applied in the field of optical communications and devices. In this work, holmium oxides doped borotellurite glass had been successfully fabricated via conventional melt-quenched technique. The structural properties of holmium doped tellurite glass were found using x-ray diffraction (XRD) method. The nonexistence of sharp peaks in XRD pattern shows that the inclusion of holmium tellurite glass leads to the formation long range of disorderness. The optical properties of the glass system such as refractive index and optical band gap energy are investigated using UV-Vis spectrophotometer. The value of refractive index is found in nonlinear trend along with holmium oxides concentration. It is found that the refractive index is more than 2 at 0.01, 0.03 and 0.04 of holmium concentrations. The optical band gap energy was found in similar trend with refractive index which is in nonlinear pattern.


2017 ◽  
Vol 36 (8) ◽  
pp. 789-793 ◽  
Author(s):  
Morteza Enhessari

AbstractNanoscale FeAl2O4 was successfully synthesized via sol–gel method. The sol constituents containing iron and aluminum cations were formed homogenously in stearic acid gel (formation of organic precursor). The pure structural analysis and the size of the spinels were confirmed by X-ray diffraction (XRD). It was observed that the size of the nanoscale materials obtained at around 30–40nm. The micrographs of FeAl2O4 evidenced the homogenous and nanosize formation of spinel. The semiconducting behavior of this mixed metal oxide was observed at 3.14eV based on the band gap energy (Eg). The final nanoscale materials exhibited a superparamagnetic behavior with a saturation magnetization of 9.8 emu/g at applied field of 10 kOe.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Maria E. Manríquez ◽  
Luis Enrique Noreña ◽  
Jin An Wang ◽  
Lifang Chen ◽  
Jose Salmones ◽  
...  

The photocatalytic degradation of 4-chlorophenol in water using Ru-doped ZnO mixed oxides (0, 0.5, 1, and 3 wt% RuO2) synthesized by the one-pot homogeneous coprecipitation method is reported. ZnO with wurtzite structure was present in the mixed oxide as corroborated by Raman spectroscopy and X-ray diffraction analysis. All the samples showed nanorod morphological features. The presence of Ru6+/Ru4+ couples on ZnO modified the band gap of the mixed oxides and led to a shift of the band gap energy from 3.20 eV to 3.07 eV. Ru addition increased the surface area and significantly promoted the formation of active surface oxygen species such as hydroradicals evidenced by the fluorescence spectroscopy measurement. In the photodegradation of 4-chlorophenol solution under UV irradiation, a notable increase in photoactivity was obtained as the amount of RuO2 in the mixed oxides increased to 3 wt%. The charge transfer between Ru6+/Ru4+ couples and ZnO nanoparticles together with the formation of free radical oxidant species effectively inhibits electron-hole recombination rate, thus favoring the photodegradation of 4-chlorophenol.


2013 ◽  
Vol 821-822 ◽  
pp. 80-84
Author(s):  
Bin Li ◽  
Xiao Gang Yang ◽  
Fang Lin Du

Bismuth-based oxides have attractive photocatalytic properties under visible light. Bismuth vanadate (BiVO4) particles as a visible light-responsive photocatalyst were prepared by a facile hydrothermal reaction method with the different solvent using Bi(NO3)3·5H2O and NH4VO3 as raw materials at 180°C for 18h. The as-prepared samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis absorption spectra (UV-vis). The photocatalytic activity of BiVO4 crystals was evaluated using the photocatalytic oxidation of methylene blue (MB) at room temperature under visible light irradiation. It was found that the morphology and the band gap adsorption edge of BiVO4 are different with the different solvent. The widest band gap energy of BiVO4 obtained with ethylene glycol as solvent is 2.405eV. In addition, the BiVO4 powders exhibit a certain photocatalytic properties to photodegrade MB and the maximum photocatalytic degradation rate is 34% using BiVO4 prepared with water as solvent for 2h.


2009 ◽  
Vol 609 ◽  
pp. 243-247 ◽  
Author(s):  
H. Moualkia ◽  
S. Hariech ◽  
M.S. Aida

The present work deals with the preparation and characterization of cadmium sulfur (CdS) thin films. These films are prepared by chemical bath deposition on the well cleaned glass substrates. The thickness of the samples was measured by using profilometer DEKTAK, structural and optical properties were studied by X-ray diffraction analysis, and UV-visible spectrophotometry. The optical properties of the films have been investigated as a function of temperature. The band gap energy and Urbach energy were also investigated as a function of temperature. From the transmittance data analysis the direct band gap ranges from 2.21 eV to 2.34 eV. A dependence of band gap on temperature has been observed and the possible raisons are discussed. Transmission spectra indicates a high transmission coefficient (75 %). Structural analysis revealed that the films showed cubic structure, and the crystallite size decreased at a higher deposition temperature.


2017 ◽  
Vol 889 ◽  
pp. 234-238
Author(s):  
Mohd Hasmizam Razali ◽  
Nur Arifah Ismail ◽  
Mahani Yusoff

Pure and F doped TiO2 nanotubes was synthesized using simple hydrothermal method. The hydrothermal was conducted using teflon-liner autoclave and maintained at 150oC for 24 hours. The characterization of synthesised product was carried out using x-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive of x-ray spectroscopy (EDX) and ultra violet – visible light diffuse reflectance spectroscopy (UV-Vis DRS) for band gap measurements. XRD patterns indicated that anatase TiO2 phase was remained after F doping suggested that fluorine was highly dispersed into TiO2 by substituted with O in the TiO2 lattice to formed TiO2-xFx solid solution. Morphology investigation using TEM found out small diameter of nanotubes structure within 8 – 10 nm of pure and F doped TiO2 nanotubes. The band gap energy (Eg) of both nanotubes samples were almost similar proposing that F doping does not modify the band gap energy.


2006 ◽  
Vol 6 (3) ◽  
pp. 845-851 ◽  
Author(s):  
Chitta Ranjan Patra ◽  
Sujata Patra ◽  
Alexandra Gabashvili ◽  
Yitzhak Mastai ◽  
Yuri Koltypin ◽  
...  

In this article, a simple microwave route was applied for the synthesis of nanoflakes and dendrite-type β-indium sulfide (In2S3) in high yield (>97%), using a homogeneous mixture of indium(III)chloride and thiourea in an ethylene glycol (EG)/polyethylene glycol (PEG400) solvent. The reaction was conducted in a simple domestic microwave oven (DMO). Powder X-ray diffraction (XRD), low resolution and high resolution transmission electron microscopy (LRTEM and HRTEM), selected area electron diffraction (SAED), and energy dispersive X-ray spectroscopy (EDS), were applied to investigate the crystallinity, structure, morphology, and composition of the In2S3 nano-materials. Both the as-synthesized and calcined In2S3 products were a body-centered tetragonal (bct) phase, observed by XRD and HRTEM. The length and width of the resulting nanoflakes were in the range of 70–600 nm and 4–10 nm, respectively. The optical band gap of the powder was determined by diffuse reflectance spectroscopy (DRS) and was found to be 2.44 eV. The electronic properties of the products were studied by measuring the optical absorption spectra using photo-acoustic spectroscopy. The band gap calculated by this method was found to be 2.52 eV. A possible mechanism for the formation of nanoflakes/dendrites-type In2S3 was also discussed.


2019 ◽  
Vol 969 ◽  
pp. 433-438 ◽  
Author(s):  
Dattatraya K. Sonavane ◽  
S.K. Jare ◽  
M.A. Shaikh ◽  
R.V. Kathare ◽  
R.N. Bulakhe

Glass substrates are used to deposit thin films utilizing basic and value effective chemical bath deposition (CBD) technique. The films were prepared from the mixture as solutions of manganous acetate tetrahydrate [C4H6MnO44H2O] as a manganese source, thiourea [(H2 N) 2 CS] as a sulfur source and triethanolamine (TEA) [(HOC2H4)3N] as a complexing agent.In the present paper the deposition was successfully done at 60 °C temperature. The absorption properties and band gap energy were determined employing double beam spectrophotometer. The optical band gap value calculated from absorption spectra of MnS thin film is found to be about 3.1eV.The MnS thin film was structurally characterized by X-ray Diffraction (XRD). The MnS thin film was morphologically characterized by Scanning Electron Microscopy (SEM) and elemental analysis was performed using EDS to confirm the formation of MnS.


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