Effect of pH Values on the Morphology of Zinc Oxide Nanostructures and their Photoluminescence Spectra

Authors

  • Wan-Yu Wu,

    1. Department of Materials Science, National University of Tainan, Tainan 70101, Taiwan
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  • Wen-Yen Kung,

    1. Department of Materials Science and Engineering, National Cheng Kung University, Tainan 70101, Taiwan
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  • Jyh-Ming Ting

    Corresponding author
    1. Department of Materials Science and Engineering, National Cheng Kung University, Tainan 70101, Taiwan
    2. Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, Tainan 70101, Taiwan
      †Author to whom correspondence should be addressed. e-mail: jting@mail.ncku.edu.tw
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  • S. Priya—contributing editor

  • This work was financially supported by the Top University Program at the National Cheng Kung University under R048/D97-3360 and the National Science Council under Grand No. NSC 98-2622-E-006-012-CC2.

†Author to whom correspondence should be addressed. e-mail: jting@mail.ncku.edu.tw

Abstract

Morphology-controlled zinc oxide (ZnO) structures, including micrometer-sized rods, nanorods, urchin-like structure, flower-like structure, and fan-shaped structure, have been synthesized by a hydrothermal method without the use of a surfactant or an amine salt. The morphology control has been achieved by simply varying the solution pH value. The precursor used in the hydrothermal process was zinc carbonate hydroxide hydrate (Zn4CO3(OH)6·H2O). The solution pH value was varied through the addition of NaOH(aq) or HCl(aq). The mechanisms for the formation of different morphologies are discussed. Despite the difference in the morphology, the resulting ZnO nanostructures all exhibit violet emission from 379.7 nm (3.27 eV) to 404.9 nm (3.06 eV), which suggests the application of the ZnO nanostructures in violet light-emitting diodes.

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