Detection of ethanol vapours with Al-incorporated ZnO thin films

Huan Hsung Hsu, Chun Kuo Tsai, Michelle Wang, Yeu Juin Tuan, H. Paul Wang

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1 Citation (Scopus)

Abstract

Al2O3 has been incorporated in the nanosize ZnO (Al/ZnO) thin film to enhance its sensitivity (Rair/RC2H5OH) to C2H5OH vapour. It is found that the Al/ZnO thin film has a high sensitivity (>20), which is much greater than the plain ZnO by at least 50%. The speciation of zinc in the Al/ZnO thin films during detection of C2H5OH (200 ppm) has also been studied by in situ X-ray absorption near edge structure (XANES) spectroscopy. The least-square fitted XANES spectra indicate that the main zinc species in the thin film are bulky ZnO (4100 nm) (5%) and nanosize ZnO (95%). At the temperature of 300 K, during sensing of C2H5OH, a small amount of Zn(OH)2 (7%) is formed in the thin film. The chemical interaction between C2H5OH and ZnO has also been found by in situ extended X-ray absorption fine structure (EXAFS) spectroscopy. The bond distance of Zn-O is decreased to 1.93Å during sensing of C2H5OH, which may be caused by the electron donating to ZnO during adsorption of C2H5OH (C2H5HO→Zn-O). In the absence of C2H5OH, the Zn-O bond distance is restored to 1.92Å.

Original languageEnglish
Pages (from-to)7-12
Number of pages6
JournalJournal of Experimental Nanoscience
Volume6
Issue number1
DOIs
Publication statusPublished - 2011 Feb 1

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Biomedical Engineering
  • Materials Science(all)

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