Structural and optical properties of ZnO thin films prepared by molecular precursor and sol–gel methods

Theopolina Amakali, Likius S. Daniel, Veikko Uahengo, Nelson Y. Dzade, Nora H. de Leeuw

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18 Scopus citations


Zinc oxide (ZnO) is a versatile and inexpensive semiconductor with a wide direct band gap that has applicability in several scientific and technological fields. In this work, we report the synthesis of ZnO thin films via two simple and low-cost synthesis routes, i.e., the molecular precursor method (MPM) and the sol–gel method, which were deposited successfully on microscope glass substrates. The films were characterized for their structural and optical properties. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for piezoelectric applications. The surface roughness derived from atomic force microscopy (AFM) analysis indicates that films prepared via MPM were relatively rough with an average roughness (Ra) of 2.73 nm compared to those prepared via the sol–gel method (Ra = 1.55 nm). Thin films prepared via MPM were more transparent than those prepared via the sol–gel method. The optical band gap of ZnO thin films obtained via the sol–gel method was 3.25 eV, which falls within the range found by other authors. However, there was a broadening of the optical band gap (3.75 eV) in thin films derived from MPM.

Original languageEnglish (US)
Article number132
Issue number2
StatePublished - Feb 2020

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Inorganic Chemistry

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