Effects of Deposition Parameters on the Electrochemical Behaviour of ZnO Thin Film

In this work, the electrochemical deposition of zinc oxide (ZnO) thin film on indium tin oxide (ITO) glass substrate from aqueous zinc nitrate was studied. Among the deposition parameters employed were deposition temperature, deposition potential, and deposition time. The morphology of the ZnO thin film was studied via FESEM.The electrochemical behaviour of the deposited ZnO thin flim was studied via cyclic voltammetry (CV) experiments. The deposition parameters lead to significant influence on the morphology and electrochemical behaviour of the thin films. The coverage area of the nanorods increased with the increase of temperature. Irregular structures of ZnO were obtained at lower deposition temperature at 60 °C. However, as the temperature increased to 90 °C, hexagonal shaped nanorods could be observed. As for the deposition potential, as the potential becomes more negative, more nucleation centers are activated and the rods are more vertical. The surface coverage is small, and increases with the deposition time. The compactness of the ZnO deposited is the highest with hexagonal rods covering the substrate at higher deposition time. The optimum electrochemical behavior of ZnO modified electrode was obtained from the deposition temperature of 60 °C using a deposition potential of -0.9 V for 900 seconds