Journal of Physics: Conference Series

Comparison of ZrO2:Y Nanocrystals and Macroscopic Single Crystal Luminescence

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Krisjanis Smits, Donats Millers, Larisa Grigorjeva, Janusz D. Fidelus, Witold Lojkowski

Abstract. The luminescence spectra of a tetragonally structured ZrO2:Y single crystal and
nanocrystals were compared. It was found that the number of luminescence centers contributed
to the spectra. The excitation of luminescence within the band gap region led to different
luminescence spectra for the single crystal and nanocrystal samples, whereas recombinative
luminescence spectra were the same for both samples. The origin of this difference is that in
the nanocrystals, even under excitation within the band gap, charge carriers were created.
Zirconium- oxygen complexes distorted by intrinsic defects were proposed to be the
luminescence centres responsible for the wide luminescence band observed.

Journal of Physics: Conference Series 93 (2007) 012035

doi:10.1088/1742-6596/93/1/012035

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The Luminescence Properties of ZnO nanopowders

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Aleksandr Kalinko, Janusz D. Fidelus, Larisa Grigorjeva, Donats Millers, Claude J. Monty, Adam Presz and Krisjanis Smits

Abstract. Pure and Al3+ doped ZnO nanopowders were studied by means of time-resolved
luminescence spectroscopy. The powders were synthesized by hydrothermal and plasma
methods. These powders were used as a raw material for vaporization-condensation process
inside the Solar reactor. The commercially available ZnO nanopowder was studied for a
comparison. Exciton to defect band luminescence intensity ratio was estimated in different
types of ZnO nanopowders. It was found that nanopowders with whiskers morphology show
superlinear luminescence intensity depending on excitation density. The observed effect
depends on the average nanoparticle size and on the powder morphology.

IOP Publishing
Journal of Physics: Conference Series 93 (2007) 012044

doi:10.1088/1742-6596/93/1/012044

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