Preparation and characterization of a ZnO nanowires-based cylindrical hierarchical structure

ZnO nanowires were synthesized with hydrothermal method on an optical fiber core, hence generating a cylindrical hierarchical structure. With a rough surface superimposed on a cylindrical substrate, the morphology of this hierarchical structure was simulated and investigated. SEM images along with relative operators of MatLab software were employed to characterize the morphology of the hierarchical structure and the geometric parameters of ZnO nanowires. Characteristic parameters including root mean square(RMS) roughness, skewness and kurtosis of the line edge profile of ZnO nanowires film were extracted respectively as 39.2 nm, 0.1324 and 2.7146, whilst the surface morphology of the cylindrical hierarchical structure with same values of characteristic parameters were simulated. It was concluded that the properties of the line edge profile were in agreement with that of the simulated surface. Also the effects of the synthesizing parameters on the geometric properties of ZnO nanowires were investigated, resulting in a group of ideal synthesizing parameters as 1.0 mmol/L Zn²⁺ concentration of the seed layer solution, 0.03 mol/L Zn²⁺ concentration of the growth solution, 1.5 h of the growth time and 90 °C of the growth temperature. The results can be used for not only the batch fabrication of this cylindrical hierarchical structure, but also the construction of related ZnO nanowires-based sensors in medical, biological, electrochemical and gas detection applications.