Structural and optical characterization of Sm-doped ZnO nanoparticles (original) (raw)
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Nanosystems: Physics, Chemistry, Mathematics
Wet chemical techniques have been used to synthesize undoped and Mn-doped nanoparticles at room temperature. Highly stable pure and 5.0 weight% Mn-doped ZnO nanoparticles have been prepared. The morphologies, structures and optical properties of the as-prepared samples were characterized by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy and UV-Vis spectra. The results clearly reveled that both the pure and doped samples had a wurtzite hexagonal phase. The SEM studies illustrated that grain size decreases with Mn doping, with average diameter ∼30 nm, which is in good agreement with the average crystalline size calculated by Scherrer's formula. The strong absorption band in the UV region for the prepared samples can be attributed to the band edge absorption of the wurtzite hexagonal ZnO.
Structural and Optical Properties of Mn Doped ZnO Nanoparticles
Nanostructured semiconductors are of great interest due to their fascinating physiochemical properties, contrary to their bulk counterparts. Zinc oxide is a potential material for spintronic devices. That can also be used for fabrication of gas sensors, piezoelectric transducers and solar cell windows. We have synthesized the Mn doped zinc oxide nanoparticles using sol gel technique for Mn concentration x = 0.01, 0.02, 0.03 and 0.05. The samples are characterized with powder x-ray diffraction for phase purity. All the samples are found in single phase with wurtzite lattice structure. The UV/V spectra of nanoparticles indicate a decrease in the band gap from 3.08 eV to 3.05 eV with 1 % change in Mn concentration. But further increase in Mn concentration results in the increase of band gap to 3.12 eV. The Photoluminescence spectra are recorded in order to observe the effect of Mn doping on emission bands of ZnO.
Growth, X-ray peak broadening studies, and optical properties of Mg-doped ZnO nanoparticles
Materials Science in Semiconductor Processing, 2013
Undoped and Mg-doped ZnO nanoparticles (NPs) (Zn 1 À x Mg x O, x ¼0.01, 0.03, and 0.05) were grown by the sol-gel method. X-ray results showed that the products were crystalline with a hexagonal wurtzite phase. Microscopy studies revealed that the undoped ZnO NPs and Zn 1 À x Mg x O NPs had nearly spherical and hexagonal shapes. The size-strain plot (SSP) method was used to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of the undoped and Mg-doped ZnO NPs. Some physical parameters such as strain, stress, and energy-density values were calculated for all reflection peaks of the XRD corresponding to the wurtzite hexagonal phase of ZnO in the 20-1001 range from the SSP results. The effect of doping on the bandgap was also investigated by a photoluminescence (PL) spectrometer. The PL results showed that Mg 2 þ is a good dopant to control band gap of the ZnO properties.
Structural and optical properties of pure and Al doped ZnO nanocrystals
Pure and Al doped zinc oxide (ZnO) were prepared by co-precipitation method. The dopant concentration [Al/Zn in atomic percentage (wt%)] was varied from 0 to 3 wt%. Structural characterisation of the samples performed with XRD and SEM–EDAX confirmed that polycrystalline nature of samples containing ZnO nanoparticles of size in the range of 97–47 nm. UV–Vis studies showed that the absorbance peaks, observed in the wavelength range of 800–250 nm, decreased with the increase in dopant concentration indicating widening of the band gap. The calculations of band gap (analyzed in terms of Burstein–Moss shift) from the reflectance showed an increase from 3.37 to 3.49 eV with increasing Al concentration.
Optik, 2019
Doping of group II elements in ZnO is an efficient way to enhance the optical properties of ZnO nanoparticles. For this purpose, Zn 1-x Mg x O nanoparticles (x = 0, 0.02, 0.04, 0.06, 0.08 and 0.1) are synthesized using co-precipitation technique. Effect of 'Mg' doping on structural, morphological, optical and thermal properties of ZnO nanoparticles is investigated. XRD results verify that synthesized nanoparticles are poly-crystalline with typical hexagonal wurtzite structure and possess no other impurity or dopant phases. Crystallite size is increased with the increase in 'Mg' content. SEM analysis reveals that polyhedral grains are aggregated with the increase in doping concentration of Mg. For the highest dopant concentration, surface morphology is entirely changed with the formation of nanowires. Optical band gap energy of Mg-doped ZnO nanoparticles is greater than that of pristine ZnO nanoparticles. The blue shift in band gap is observed with Mg content x ≤ 0.04, followed by red shift for higher Mg content. The decrease in phase transition and increase in decomposition temperature for Mg-doped ZnO nanoparticles suggest their thermal stability. Tailoring of band gap makes ZnO nanoparticles a promising material for photocatalysis, optoelectronic and display devices. 1. Introduction Zinc oxide (ZnO) is considered as one of the front runners among different metal oxide semiconductors due to its fascinating physical and chemical properties. It has wide direct band gap energy (˜3.2-3.37 eV) and high exciton binding energy (60 meV). These properties make ZnO an efficient material for short wavelength optoelectronic and nanoelectronic devices [1,2]. Its superior piezoelectric property and stability against photo-corrosion make it attractive for surface acoustic wave devices, gas sensors, solar cells and transparent electrodes [3-5]. Its non-toxicity, biocompatibility, chemical stability and photochemical properties make it suitable for drug delivery, antibacterial and photo-catalytic applications [6-8]. ZnO, at nanoscale, exhibits unique structural, optical, electronic and chemical properties, entirely different from its bulk counterpart. The properties of ZnO nanostructures depend on crystalline structure and morphology, particle size and their shape, which in turn are dependent on synthesis methods of ZnO nanostructures. In general, physical, chemical and green methods are employed to fabricate ZnO nanomaterials [9-12]. Among these, chemical method is a simple and cost-effective technique. It can be performed at room or low temperature, using a wide range of precursors and synthesis conditions such as concentration of reactants, time, temperature etc. Control of these parameters results into ZnO nanostructures with different geometries and sizes. These
Synthesis and study of structural properties of Sn doped ZnO nanoparticles
Materials Science Poland, 2016
Pure and Sn-doped ZnO nanostructures were synthesized by simple chemical solution method. In this method we used zinc nitrate and NaOH as precursors. Sn doping content in ZnO was taken with the ratio 0, 5, 10, 15 and 20 percent by weight. Physical properties of Sn-doped ZnO powder were studied by XRD analysis which revealed that Sn doping had a significant effect on crystalline quality, grain size, intensity, dislocation density and strain. The calculated average grain size of pure ZnO was 21 nm. The best crystalline structure was found for 0 wt.%, 5 wt.% and 10 wt.% Sn doping as observed by FESEM and XRD. However, higher Sn-doping (>10 wt.%) degraded the crystallinity and the grain size of 27.67 nm to 17.76 nm. The structures observed in FESEM images of the samples surfaces were irregular and non-homogeneous. EDX depicted no extra peak of impurity and confirmed good quality of the samples.
Structural and optical properties of Mn doped Zinc oxide
2011
Nanostructured semiconductors are of great interest due to their fascinating physiochemical properties, contrary to their bulk counterparts. Zinc oxide is a potential material for spintronic devices. That can also be used for fabrication of gas sensors, piezoelectric transducers and solar cell windows. We have synthesized the Mn doped zinc oxide nanoparticles using sol gel technique for Mn concentration x = 0.01, 0.02, 0.03 and 0.05. The samples are characterized with powder x-ray diffraction for phase purity. All the samples are found in single phase with wurtzite lattice structure. The UV/V spectra of nanoparticles indicate a decrease in the band gap from 3.08 eV to 3.05 eV with 1 % change in Mn concentration. But further increase in Mn concentration results in the increase of band gap to 3.12 eV. The Photoluminescence spectra are recorded in order to observe the effect of Mn doping on emission bands of ZnO.
Physica E: Low-dimensional Systems and Nanostructures, 2014
Mn-doped ZnO nanoparticles (NPs) of different compositions have been synthesized by chemical co-precipitation method. The products were sintered at 800 � C. X-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), scanning electron microscopy (SEM), photoluminescence spectroscopy (PL) and UV-Vis spectroscopy have been used to characterize the samples. The XRD studies revealed that Mn-doped ZnO has Wurtzite structure. The SEM images show different morphology for different compositions. Violet, blue and green emissions have been observed for Mn-doped ZnO NPs as evidenced from the photoluminescence spectra. The optical energy band gap of the NPs has no correlation with Mn concentration.
Transition metal (Co, Mn) co-doped ZnO nanoparticles: Effect on structural and optical properties
Journal of Alloys and Compounds, 2017
Pure ZnO and Co/Mn co-doped ZnO {Zn 0.98-x Co 0.02 Mn x O (0≤x≤0.06)} nanoparticles were synthesized by co-precipitation method. The structural, morphological and optical properties of prepared samples were explored in detail. Rietveld refinement of x-ray diffraction (XRD) data revealed the single phase, hexagonal wurtzite structure without any impurity phase. XRD and Fourier transform infra-red (FTIR) analysis confirmed the incorporation of Co/Mn ions at Zn site into host lattice structure. The morphology of samples was examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. The particle size from TEM results was corroborated well with XRD data. The absorption spectra showed the initial decrease in optical energy band gap for low Mn concentration. The optical energy band gap further increased with a higher Mn concentration in codoped ZnO samples. Photoluminescence (PL) spectra showed five emission peaks due to different defect states. The paper enhances the understanding of structural, optical properties of Co/Mn co-doped nanocrystals. This paves the path for its potential application in the optoelectronic devices e.g. solar cell.