Hydrothermal synthesis and cathodoluminescence of ZnO crystalline powders and coatings
Nanocrystalline ZnO powders and coatings of ZnO were obtained under soft hydrothermal conditions. The growth systems contained various ZnO-precursors (as-prepared Zn-hydroxide, chemical ZnO, Zn(NO 3) 2), solvents (LiOH, KOH, NH 4OH) and Zn-substrate. ZnO growth morphology was found to depend on the...
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Veröffentlicht in: | Journal of crystal growth 2006-01, Vol.287 (1), p.23-27 |
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Hauptverfasser: | , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Nanocrystalline ZnO powders and coatings of ZnO were obtained under soft hydrothermal conditions. The growth systems contained various ZnO-precursors (as-prepared Zn-hydroxide, chemical ZnO, Zn(NO
3)
2), solvents (LiOH, KOH, NH
4OH) and Zn-substrate. ZnO growth morphology was found to depend on the chemical composition of the solvent: Li
+ suppresses the growth of (0
0
0
1) faces, NH
4
+ promotes it. Aspect ratio of crystals is controlled by solvent type and concentration. Luminescent properties have been studied using impulse laser or cathode excitation. The ratio
I
UV/
I
VIS in luminescence spectra was found to depend on the excitation mode. Laser excitation allows to obtain UV-band with higher intensity in comparison with cathode excitation. The most intensive UV luminescence was found for polycrystalline coatings on Zn-substrates obtained in the systems with KOH as a solvent. Mathematic treatment of the ICL spectra was carried out; the wide VIS-band was found to consist of the series of overlapping bands. UV luminescence quenching centers were suggested to be connected mainly with the irradiation in VIS-region with
c
λ
>
700
nm
. |
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ISSN: | 0022-0248 1873-5002 |
DOI: | 10.1016/j.jcrysgro.2005.10.036 |