Morphological and Structural Study of Vertically Aligned Zinc Oxide Nanorods Grown on Spin Coated Seed Layers

Abstract

In this study, vertically aligned zinc oxide (ZnO) nanorod (NR) arrays were grown with the 2-step method. Spin coating was used to apply the seed layer, and by increasing the number of repetitions (n), higher thickness of the seed layer was achieved. The effects of different seed layer thicknesses, spin coated at different rotational speeds (v) and how the variables (v and n) influence the morphological and crystal properties of the resulting ZnO NRs were analyzed. The effects of 1, 3, and 5 (n), with (v) of 3000 or 4000 rpm were investigated, and the formed seed layers were characterized by using scanning electron microscopy (SEM) and X-ray diffraction (XRD) profiles. The ZnO NR arrays were grown by a chemical bath deposition method because of its simplicity and ease of use. Full width at half maximum (FWHM) analysis was conducted on the XRD chart and Raman spectrum to analyze the grain size and Wurtzite distortion of the ZnO NRs. A lower FWHM value was attributed to the lower number of structural disorders in the ZnO NRs, which equated to the most stable or structured Wurtzite structures in the ZnO NRs, achieved at the lowest FWHM value. The lowest FWHM for (002) XRD peak was obtained at 0.35° for ZnO NRs grown with a seed layer spin coated at 4000 rpm once. The crystallite size calculated by Scherrer’s equation gave a size of 25.14 nm. The lowest FWHM for E2(High) Raman peak was obtained at 6.00 cm–1 for ZnO NRs grown with a seed layer spin coated at 4000 rpm three times.

Keywords

• Chemical bath deposition
• Nanorods
• Spin coating
• Vertical growth
• ZnO