Structural, optical properties and optical modelling of hydrothermal chemical growth derived ZnO nanowires

Abstract

ZnO nanowire films were produced at 90 °C using a hydrothermal chemical deposition method, and were characterised with scanning electron microscopy, optical transmission spectrometry and X-ray diffraction. The results showed that the optical band gap is 3.274–3.347 eV. Film porosity and microstructure can be controlled by adjusting the pH of the growth solution. ZnO nanowire films comprise a 2-layer structure as demonstrated by SEM analysis, showing different porosities for each layer. XRD analysis shows preferential growth in the (002) orientation. A comprehensive optical modelling method for nanostructured ZnO thin films was proposed, consisting of Bruggeman effective medium approximations, rough surface light scattering and O'Leary-Johnson-Lim models. Fitted optical transmission of nanostructured ZnO films agreed well with experimental data.