Microstructural and chemical properties of ZnO films formed using electrodeposition

We investigated the effect of bath temperature and electrodeposition potential on the microstructural and chemical properties of ZnO films formed on Mo-coated soda-lime glass substrates using electrodeposition. The electrodeposition was performed using an electrolytic solution containing 0.05 M Zn(NO₃)₂ for 6 min. The ZnO islands grew larger to impinge with other islands until the bath temperature was increased up to 40 °C, above which continuous ZnO film was eventually formed. An increase in the electrodeposition potential resulted in enhancement of the growth rate of the electrodeposited ZnO film with the facilitation of film texturation. The c-axis was perpendicular to surface, which could be associated with the preferential orientation along the (002) direction. At the electrodeposition potential of -1.3 V (vs. a saturated calomel electrode), significant amounts of hydrogen bubbles that electrochemically evolved near the surface of the working electrode hampered the homogenous growth of the ZnO film, which could be responsible for morphological degradation of the ZnO film.