Elektrodepozisyon Yapılan ZnO İnce Filmlerinin Korozyon Davranışı

Abstract

Electrochemical deposition method (ECD) has been widely used due to its advantages in stoichiometry control, large area growth, easy to form nano-structures, being low coast, possible formation of homogeneous thin films. In this study, nanostructured zinc oxide (ZnO) thin films were deposited on Indium tin oxide (ITO)-coated glass substrate using ECD. The effects of cathodic potential, time, temperature and pH on quality of the films were examined. ZnO thin films were achieved with in cathodic potential with -1.0 V and deposition time with 3600 seconds at temperature 130°C in dimethyl sulfoxide (DMSO). X-ray diffraction (XRD) analysis confirmed clearly that the ZnOthin films have sinle crystalline properties with a strong c-axis (0002) preferential orientation. According to the absorption measurements, the optical bandgap of the ZnOfilm was calculated as Eg 3.4 eV. ZnO thin films electrodeposited on ITO substrate were studied with Electrochemical Impedance Spectroscopy (EIS) and Tafel measurements. Nyquist, open circuit potential and Bode analysis were evaluated to find out the structural changing of ZnOand its corrosion behavior. With the help of these plots, solution resistance (Rs), polarization resistance (Rp), a constant phase element (CPE) and a CPE exponent (n) were calculated as 49.61 Ω, 4.97x106 Ω, 6.75x10-6 Ω-1.s.cm-2, 0.940, respectively. Also, we examined the ZnO thin films corrosion features with the help of tafel measurements. Considering all these measurement, the possible reason of increasing corrosion resistance can be interpreted as surface passivation depending on increasing defects caused by deposition.