Journal of Materials Research

Articles

Effect of surface defects on the visible emission from ZnO nanoparticles

Harish Kumar Yadava1, K. Sreenivasa1, Vinay Guptaa1 c1, S.P. Singha2 and R.S. Katiyara3

a1 Department of Physics and Astrophysics, University of Delhi, Delhi-110007, India

a2 National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi-110012, India

a3 Department of Physics, University of Puerto Rico, San Juan, Puerto Rico 00931-3343

Abstract

The luminescent property of ZnO nanoparticles prepared using the wet chemical method has been investigated. The ZnO nanoparticles in the range 5–10 nm exhibit hexagonal Wurtzite structure, and the photoluminescence (PL) spectrum at room temperature shows a broad visible luminescence band and insignificant near-bandgap emission. The broad green luminescence is dominant at both room and boiled off liquid-nitrogen temperature, while the ultraviolet band edge emission is strongly quenched. The prepared ZnO nanoparticles have residual intermediate compound on the surface in the form of an acetate group, which acts as defect centers for the emission of green luminescence. A trace amount of zinc hydroxide is observed in one of the samples and is found to further enhance the intensity of the green luminescence. Raman scattering studies on nanoparticles indicate that the acetate/hydroxyl groups are loosely bound on the surface and are not present in the interior of the ZnO crystal structure

(Received August 29 2006)

(Accepted December 20 2006)

Key Words:

  • Nanostructure;
  • Photoemission;
  • Oxide

Correspondence:

c1 Address all correspondence to this author. e-mail: vgupta@physics.du.ac.in

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