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Effect of pH on Crystal Size and Photoluminescence Property of ZnO Nanoparticles Prepared by Chemical Precipitation Method

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Acta Metallurgica Sinica(English Letters) 2015年第3期28卷 394-404页

作者： M.Jay Chithra M.Sathya K.Pushpanathan pg & research department of physics Government Arts College

The effects of pH value on crystal size and optical property of zinc oxide nanoparticles prepared by chemical precipitation method were investigated.Prepared samples have been characterized by means of X-ray diffraction,scanning electron microscopy,ultraviolet-visible spectrometer and photoluminescence spectrometer.From X-ray diffraction profile,it is found that the particle size of sample increases from 13.8 to 33 nm when the pH value of the solution was increased from 6 to 13.Microstructural study also shows that the particle size increases with pH value.Hexagonal shape of the zinc oxide nanoparticle has been confirmed by the scanning electron microscopy image.The recorded ultraviolet-visible spectrum shows excitonic absorption peaks around 381 nm.The energy gap of the prepared samples has been determined from the ultraviolet-visible absorption spectrum,effective mass model equation and Tauc＇s relation.It was found that the energy gap of the prepared samples decreases with increase in pH value.The recorded blue shift confirmed the quantum confinement effect in the prepared zinc oxide samples.Photoluminescence spectrum infers that the increase in pH value shifts the ultraviolet-visible emission but not the violet and green emissions.

关键词： Zinc oxide nanoparticles pH value Crystal structure Microstructure Energy gap Photoluminescence

Reply to Comments on "Structural,Optical,and Electrical Properties of Zn-Doped CdO Thin Films Fabricated by a Simplified Spray Pyrolysis Technique'' by K.Usharani and A.R.Balu published in Acta Metall.Sin.(Engl.Lett.) 28(1),64–71(2015)

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Acta Metallurgica Sinica(English Letters) 2018年第9期31卷 1007-1008页

作者： A.R.Balu pg and research department of physics AVVM Sri Pushpam College

Following are the comments for the queries raised by Prof. Pawel E. Tomaszewski on our published paper entitled ＂Structural, Optical, and Electrical Properties of Zn-Doped CdO Thin Films Fabricated by a Simplified Sp... 详细信息

关键词： Cd Engl.Lett Structural,Optical,and Electrical Properties of Zn-Doped CdO Thin Films Fabricated by a Simplified Spray Pyrolysis Technique by K.Usharani and A.R.Balu published in Acta Metall.Sin Zn

Effect of Fuel to Oxidant Molar Ratio on Structural and DC Electrical Conductivity of ZnO Nanoparticles Prepared by Simple Solution Combustion Method

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Journal of Materials Science & Technology 2013年第10期29卷 898-902页

作者： C.S.Naveen M.L.Dinesha H.S.Jayanna department of pg Studies and research in physics Kuvempu University

ZnO nanoparticles of different sizes were prepared by varying the molar ratio of glycine and zinc nitrate hexahydrate as fuel and oxidizer （0.1, 0.8, 1.11, 1.3, 1.5, 1.7, 2.0） by simple solution combustion method. UV-Visible spectrophotometry studies show that, the band gap of the prepared ZnO nanoparticles increases with increasing fuel to oxidant （F/O） molar ratio up to 1.7 revealing the formation of ZnO nanoparticles. The decrease in band gap for the sample of F/O molar ratio 2.0 is due to an increase in particle size. Powder X-ray diffraction patterns of the prepared samples show the formation of single phase ZnO nanoparticles and the particle size decreases with increasing F/O molar ratio up to 1.7. Surface morphology of the prepared samples was studied by scanning electron microscopy and it was observed that, the porosity increases with increasing F/O molar ratio. DC electrical conductivity at room temperature and in the temperature range of 303-563 K was studied for all the samples and the results revealed that, the sample of F/O molar ratio 1.7 has low electrical conductivity at room temperature and high EAR （high temperature activation energy） compared to other samples.

关键词： ZnO nanoparticles Structural characterization Electrical conductivity

Flower-shaped CuO Nanostructures: Synthesis,Characterization and Antimicrobial Activity

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Journal of Materials Science & Technology 2013年第10期29卷 909-914页

作者： K.Mageshwari R.Sathyamoorthy pg & research department of physics Kongunadu Arts and Science College

In the present work, flower-like CuO nanostructures were synthesized by reflux condensation method without using any surfactants or templates. Structural analysis by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR） and Raman studies revealed the formation of highly crystalline single phase CuO, exhibiting monoclinic structure. Morphological analysis by field emission scanning electron microscopy （FESEM） showed flower-shaped CuO hierarchical architecture made up of interpenetrating self-assembled nanosheets. Optical analysis by UV-Vis diffused reflectance spectra （DRS） exhibited considerable blue-shift in the optical band gap due to quantum confinement effect. Photoluminescence （PL） spectrum showed both UV as well as visible emissions. The antibacterial activity of flower-shaped CuO nanostructures were tested against gram-positive （Bacillus subtilis, Bacillus thuringiensis） and gram-negative （Salmonella paratyphi, Salmonella paratyphi-a, Salmonella paratyphi-b, Escherichia coil and Pseudomonas aeruginosa） bacteria. Also, the antifungal activity of CuO was investigated against Aspergillus niger, Rhizopus oryzae, Aspergi/lus flavus, Cladosporium carrionii, Mucor, Penicilliurn notatum and Alternaria alternata. Results demonstrate that the flower-shaped CuO nanostructures act as an effective antimicrobial agent against pathogenic bacteria and fungi.

关键词： CuO nanosheets Hierarchical X-ray diffraction Photoluminescence Antibacterial Antifungal

Influence of Annealing on Physical Properties of CdO Thin Films Prepared by SILAR Method

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Journal of Materials Science & Technology 2013年第1期29卷 17-21页

作者： B.Gokul P.Matheswaran R.Sathyamoorthy pg and research department of physics Kongunadu Arts and Science College (Autonomous)

Cadmium oxide （CdO） thin films were prepared by successive ionic layer adsorption and reaction （SILAR） method and annealed at 250-450 ℃ for 2 h. The prepared films were characterized by X-ray diffraction （XRD）, optical spectroscopy, scanning electron microscopy （SEM） and Hall effect measurement. The XRD analysis reveals that the films were polycrystalline with cubic structure. Both crystallinity and the grain size were found to increase with increasing annealing temperature. SEM analysis shows the porous nature of the surface with spherical nanoclusters. Energy dispersive spectroscopic analysis （EDS） confirmed the presence of Cd and O elements without any additional impurities. The films exhibited maximum transmittance （82%-86%） in infra-red （IR） region. Transmittance was found to decrease with increasing annealing temperature （Eg） was in the range of 2.24-2.44 eV. Hall effect measurement shows an and the estimated band gap energy ncrease in carrier concentration and a decrease in resistivity with increasing annealing temperature. The carrier concentration （N） and resistivity （p） of about 1.26 × 1022 cm-3 and 8.71 × 10 3 Ω cm are achieved for the film annealed at 450 ℃ for 2 h.

关键词： Annealing Porous structure Hall effect Electrical resistivity

Electronic structure and bonding interactions in Ba1-xSrxZr0.1Ti0.9O3 ceramics

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Frontiers of Materials Science 2017年第2期11卷 182-189页

作者： Jegannathan MANGAIYARKKARASI Subramanian SASIKUMAR Olai Vasu SARAVANAN Ramachandran SARAVANAN pg and research department of physics NMSSVN College Nagamalai Madurai-625 019 Tamil Nadu India research Centre and pg department of physics The Madura College Madurai-625 011 Tamil Nadu India

An investigation on the precise electronic structure and bonding interactions has been carried out on Ba1-xSrxZr0.1Ti0.9O3 （short for BSZT, x = 0, 0.05, 0.07 and 0.14） ceramic systems prepared via high-temperature solid state reaction technique. The influence of Sr doping on the BSZT structure has been examined by characterizing the prepared samples using PXRD, UV-visible spectrophotometry, SEM and EDS. Powder profile refinement of X-ray data confirms that all the synthesized samples have been crystallized in cubic perovskite structure with single phase. Charge density distribution of the BSZT systems has been completely analyzed by the maximum entropy method （MEM）. Co-substitution of Sr at the Ba site and Zr at the Ti site into the BaTiOz structure presents the ionic nature between Ba and O ions and the covalent nature between Ti and O ions, revealed from MEM calculations. Optical band gap values have been evaluated from UV-visible absorption spectra. Particles with irregular shapes and well defined grain boundaries are clearly visualized from SEM images. The phase purity of the prepared samples is further confirmed by EDS qualitative spectral analysis.

关键词： barium titanate X-ray diffraction Rietveld refinement maximum entropy method bonding

Effect of chlorine doping on the structural, morphological, optical and electrical properties of spray deposited CdS thin films

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Progress in Natural Science:Materials International 2015年第5期25卷 392-398页

作者： T.Sivaraman V.Narasimman V.S.Nagarethinam A.R.Balu pg and research department of physics A.V.V.M Sri Pushpam College

CdS and chlorine doped CdS(CdS:Cl) thin films with different Cl-doping levels(0,2,4,6 and 8 at%) have been deposited on glass substrates by a spray pyrolysis technique using a perfume atomizer.The effect of Cl doping on the structural,morphological,optical and electrical properties of the films was investigated.XRD patterns revealed that all the films exhibit hexagonal crystal structure with a preferential orientation along the(0 0 2) plane irrespective of the Cl doping level.The particle size value decreases from 22.03 nm to 18.12 nm with increase in Cl concentration.Optical band gap is blue-shifted from 2.48 eV to 2.73 eV with increase in Cl doping concentration.All the films have resistivity in the order of 10~4 Ω cm.The obtained results confirm that chlorine as an anionic dopant material can enhance the physical properties of CdS thin films to a large extent.

关键词： X-ray diffraction Crystal structure Preferential orientation Thin films Optical band gap

Characteristic analysis on the physical properties of nanostructured Mg-doped CdO thin films—Doping concentration effect

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Progress in Natural Science:Materials International 2015年第3期25卷 251-257页

作者： K.Usharani A.R.Balu V.S.Nagarethinam M.Suganya pg and research department of physics A.V.V.M Sri Pushpam College

Highly conductive and transparent magnesium-doped cadmium oxide(CdO :Mg) thin films have been deposited on suitably cleaned glass substrates maintained at 375℃ by spray pyrolysis technique using perfume atomizer. The magnesium content in the films is varied from 0 to 8 at%in steps of 2 at%. The effect of Mg doping on the structural, morphological, optical and electrical properties of the CdO thin films has been studied.All the films exhibited cubic structure with a preferential orientation along the(1 1 1) plane irrespective of the Mg doping level. SEM analysis showed that the film morphology modifies from spherical shaped grains to closely packed cauliflower shaped nanostructures with Mg doping.Except for the film coated with 2 at% Mg dopant, all the other doped films exhibited a blue shift in the optical band gap. Electrical studies revealed that the Cd O:Mg film coated with 8 at% Mg dopant had a minimum resistivity of 0.0853*10~1Ω-cm.

关键词： X-ray diffraction Texture coefficient Thin films Optical band gap Electrical properties

Structural, Optical, and Electrical Properties of Zn-Doped CdO Thin Films Fabricated by a Simplified Spray Pyrolysis Technique

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Acta Metallurgica Sinica(English Letters) 2015年第1期28卷 64-71页

作者： K.Usharani A. R.Balu pg and research department of physics AVVM Sri Pushpam College Poondi 613 503 Tamilnadu India pg and research department of physics AVVM Sri Pushpam College 757 MIG Colony New Housing UnitThanjavur 613 005 Tamilnadu India

Thin films of zinc-doped cadmium oxide with different Zn-doping levels（0, 2, 4, 6, and 8 at%） were deposited on glass substrates by employing an inexpensive, simplified spray technique using perfume atomizer at relatively low substrate temperature（375 °C） compared with the conventional spray method. The effect of Zn doping on the structural,morphological, optical, and electrical properties of the films was investigated. XRD patterns revealed that all the films are polycrystalline in nature having cubic crystal structure with a preferential orientation along the（1 1 1） plane irrespective of Zn-doping level. Zn-doping level causes a slight shift in the（1 1 1） diffraction peak toward higher angle. The crystallite size of the films was found to be in the range of 28–37 nm. The band gap value increases with Zn doping and reaches a maximum of 2.65 eV for the film coated with 6 at% Zn doping and for further higher doping concentration it decreases.Electrical studies indicate that Zn doping causes a reduction in the resistivity of the films and a minimum resistivity of15.69 X cm is observed for the film coated with 6 at% Zn.

关键词： Semiconductors Thin films Crystal structure Optical properties X-ray diffraction