Optical and magnetic characterization of transition metal ion doped ZnO microspheres synthesized via laser ablation in air
TL;DR: In this paper, the synthesis of transition metal doped (TM) ZnO micropsheres using doped znO sintered targets containing Mn 1% dopant was reported.
Abstract: We report the synthesis of transition metal doped (TM) ZnO micropsheres using doped ZnO sintered targets containing Mn 1% dopant. Transition metals are prospective materials for p type acceptor doping in ZnO. Structural and morphology study were conducted using XRD (X-ray diffraction), SEM and Raman spectroscopy. Room temperature Photoluminescence (PL) spectra of the fabricated ZnO microspheres were measured, at an excitation wavelength of 355 nm. In our study, smooth spherical shaped micro particles with different diameters ranging from ~1 to 3 μm were grown in different substrates by using a pulsed N 3+: YAG laser. SEM (Scanning Electron Microscopy) images show the presence of uniform smooth surfaced spheres. Raman scattering measurements from the synthesised samples at 532 nm wavelength excitation provide confirms the wurtzite structure of the fabricated undoped and TM doped ZnO microsphere. The doped microspheres exhibited UV whispering gallery modes (WGM) cavity lasing by optical pumping. Magnetic measurements from TM doped ZnO microparticles using vibrating sample magnetometer (VSM) are in progress.
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TL;DR: In this article, a solid state reaction is used to synthesize doped metal oxides with desired optical properties, and the presence of these oxidation states was confirmed using x-ray photoelectron spectroscopy.
Abstract: Manganese-doped zinc oxide powders were synthesized by solid state reaction of the respective oxides. The high-temperature conditions were chosen such that multiple valence states of manganese were doped in the host zinc oxide lattice. Structural characterization was carried out to confirm the doping and to find the maximum amount of manganese that can be incorporated. Diffuse reflectance spectroscopy was used to measure the optical band gap of the doped sample and the lowering with respect to pure ZnO was attributed to the presence of higher oxidation states of manganese. The presence of these oxidation states was confirmed using x-ray photoelectron spectroscopy. The study shows that a solid state reaction is a viable route for synthesizing doped metal oxides with desired optical properties.
14 citations
TL;DR: In this article, a simple laser ablation method in the air was used to synthesize ZnO nano/microspheres with diameters of up to 10μm.
Abstract: We have succeeded in synthesizing ZnO nano/microspheres by a simple laser ablation method in the air and demonstrated whispering-gallery-mode (WGM) lasing from the ZnO sphere excited by a pulsed-ultraviolet laser beam. The spheres with diameters of up to 10μm were simply prepared by laser ablation of a ZnO sintered target by a Q-switched Nd:YAG laser in the air. In this study, we succeeded synthesizing large microspheres with diameters of larger than 20μm by the Nd:YAG laser without Q-switching. The mode spacing of the large sphere was in good agreement with the WGM theory.
14 citations
TL;DR: In this paper, the growth and low-temperature photoluminescence characteristics of Ni-doped ZnO nanoneedles and V-droneed thin film grown by a modified pulsed laser deposition technique were reported.
Abstract: We report the growth and low-temperature photoluminescent characteristics of well-aligned Ni-doped ZnO nanoneedles and V-doped ZnO nanostructured thin film grown by a modified pulsed laser deposition technique. Low-temperature photoluminescence spectra of the as-grown films show the presence of free excitonic as well as bound excitonic transitions, whose relative intensity changes with increasing temperature. Ni-doped ZnO films show a characteristic fine structure in the visible range (2.6?2.9?meV) attributed to either exciton?polariton longitudinal?transverse splitting or the splitting caused by electron?hole exchange interaction. The excitonic and visible region emission can be clearly seen as can the phonon replicas produced from longitudinal optical phonons. Different possible attributions of the various peaks in the emission band at low temperature have been discussed. The as-grown nanostructures of Ni- and V-doped ZnO thin films also clearly show the effect of doping on the microstructure of ZnO.
13 citations
TL;DR: The structural, optical and magnetic properties of Zn1−xMnxO (x = 0.02, 0.04 and 0.06) prepared by solid state route are presented in this article.
Abstract: The structural, optical and magnetic properties of Zn1−xMnxO (x = 0.02, 0.04 and 0.06) prepared by solid state route are presented. The rietveld refined X-ray data revealed single hexagonal phase with the space group P63mc in all samples. Significant blue shift with Mn doping is observed in UV–Visible studies, supported by photoluminescence spectra showing a high intensity UV emission peak followed by the low intensity green emission band corresponding to oxygen vacancies and defects. Photoluminescence spectra also suggested that doping of Mn can affect defects and oxygen vacancies in ZnO and giving the possibility of band gap tuning for potential applications in optoelectronic devices. All single-phase samples exhibit paramagnetic behaviour at room temperature, involving small proportion of defect mediated ferromagnetic ordering.
8 citations
TL;DR: X-ray diffraction studies show that the crystallinity and purity of electrodeposited ZnO improved by using a moderate thermal annealing, and the potential of the electrochemically-formed ZNO nanostructures as a suitable template for electrochemical deposition of polypyrrole (Ppy) is investigated.
Abstract: The controlled growth of oriented ZnO nanostructures is desirable for their varied applications. In this study, an electrochemical technique is used for deposition of ZnO. The large area morphology shows sheet-like structures oriented perpendicular to the substrate. X-ray diffraction studies show that the crystallinity and purity of electrodeposited ZnO improved by using a moderate thermal annealing. TEM shows randomly oriented rod-like structures. The Raman spectra further confirm the crystallinity of the films. The photoluminescence spectra show emission peaks in the blue-green visible region. Furthermore, we also investigate the potential of the electrochemically-formed ZnO nanostructures as a suitable template for electrochemical deposition of polypyrrole (Ppy).
8 citations