Chemical Route to Synthesis Hierarchical ZnO Thick Films for Sensor Application

ZnO hierarchical structure has been synthesis by using chemical routs method. Hydra zinc nitrate, oleic acid, ethanol was used as row materials for the chemical reaction in the presence of NaOH. The Reaction took place at room temperature under stirrer. The prepared ZnO powder is collected and mixed with PVA to make a proper paste, then the paste was screen-printed in 1 cm square pattern to make thick films. Afterwards, the films are annealed at 500 C˚ for an hour. The morphology, crystallinity and structural properties are studied by X-ray diffraction, the experimental pattern of the films show very fine peaks indicate a good crystallization, also the morphology of the films studied by atomic force microscope and field emission scanning electron microscope. The sensitivity of zinc oxide NRs films to 100 ppm vapor methanol, ethanol and NH3 gas as a function of working temperature. As evident, the sensitivity increases with the temperature and reaches a maximum value in correspondence of T = 200-300 °C. If the temperature increases again, the sensitivity decreases.