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Open Access Nano Express

The Modulation of Optical Property and its Correlation with Microstructures of ZnO Nanowires

Haohua Li123, Chaolun Liang4, Kuan Zhong123, Meng Liu123, Greg A Hope5, Yexiang Tong123* and Peng Liu123*

Author Affiliations

1 School of Chemistry and Chemical Engineering, Sun Yat-Sen University, 510275, Guangzhou, People’s Republic of China

2 MOE of Key Laboratory of Bioinorganic and Synthetic Chemistry, Sun Yat-Sen University, 510275, Guangzhou, People’s Republic of China

3 Institute of Optoelectronic and Functional Composite Materials, Sun Yat-Sen University, 510275, Guangzhou, People’s Republic of China

4 Instrumental Analysis & Research Center, Sun Yat-Sen University, 510275, Guangzhou, People’s Republic of China

5 School of Science, Griffith University, Nathan, QLD, 4111, Australia

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Nanoscale Research Letters 2009, 4:1183-1190  doi:10.1007/s11671-009-9381-z

Published: 1 July 2009

Abstract

ZnO nanowires with both good crystallinity and oxygen vacancies defects were synthesized by thermal oxidation of Zn substrate pretreated in concentrated sulfuric acid under the air atmosphere, Ar- and air-mixed gas stream. The photoluminescence spectra reveal that only near-band-edge (NBE) emission peak was observed for the sample grown in the air atmosphere; the broad blue–green and the red-shifted NBE emission peaks were observed for the sample grown in the mixed gas stream, indicating that the sample grown in the mixed gas stream has a defective structure and its optical properties can be modulated by controlling its structure. The high-resolution transmission electron microscope and the corresponding structural simulation confirm that the oxygen vacancies exist in the crystal of the nanowires grown in the mixed gas stream. The ZnO nanowires with oxygen vacancies defects exhibit better photocatalytic activity than the nanowires with good crystallinity. The photocatalytic process obeys the rules of first-order kinetic reaction, and the rate constants were calculated.

Keywords:
ZnO nanowires; Thermal oxidation; Oxygen vacancies; Photoluminescence; Photocatalysis