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The effects of annealing temperatures and chelating agents on the structural and optical properties of ZnO nanoparticles were investigated. The average particle size of ZnO nanoparticles increased with increase of annealing temperatures. The decrease of the full width at half maximum (FWHM) with increasing annealing temperatures inferred increase of particle/grain growth. The grain sizes were also observed to be increased with increase of annealing temperatures. From the absorption spectra of the samples, the absorption was red-shifted and the energy band gap was blue-shifted with increase of annealing temperatures. A sharp UV emission peak was observed and the intensity of this peak increased with annealing temperatures corresponding to the high crystallinity in the samples. At high annealing temperature of 700 ℃, ZnO exhibited a less intense deep level emission. This negligible deep level emission was attributed to the oxygen vacancies created at higher annealing temperatures.


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Annealing effects on the structural and optical properties of ZnO nanoparticles with PVA and CA as chelating agents

Show Author's information A. N. MALLIKA( )A. Ramachandra REDDYK. Venugopal REDDY
Department of Physics, Materials Science Laboratory, National Institute of Technology, Warangal-506004, Telangana, India

Abstract

The effects of annealing temperatures and chelating agents on the structural and optical properties of ZnO nanoparticles were investigated. The average particle size of ZnO nanoparticles increased with increase of annealing temperatures. The decrease of the full width at half maximum (FWHM) with increasing annealing temperatures inferred increase of particle/grain growth. The grain sizes were also observed to be increased with increase of annealing temperatures. From the absorption spectra of the samples, the absorption was red-shifted and the energy band gap was blue-shifted with increase of annealing temperatures. A sharp UV emission peak was observed and the intensity of this peak increased with annealing temperatures corresponding to the high crystallinity in the samples. At high annealing temperature of 700 ℃, ZnO exhibited a less intense deep level emission. This negligible deep level emission was attributed to the oxygen vacancies created at higher annealing temperatures.

Keywords: scanning electron microscopy (SEM), optical properties, polyvinyl alcohol (PVA), ZnO nanostructures, citric acid (CA), chelating agents

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Publication history
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Publication history

Received: 14 November 2014
Revised: 30 December 2014
Accepted: 24 January 2015
Published: 30 May 2015
Issue date: June 2015

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© The author(s) 2015

Acknowledgements

The authors are thankful to the dean of School of Physics, University of Hyderabad, for providing XRD facility. The authors also would like to thank the Sophisticated Analytical Instrument Facility (SAIF) STIC India, Cochin, for the characterization of absorption spectra of the samples.

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Open Access: This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.

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