ZnO electrodeposition on gold electrode was investigated by electrochemical and optical methods. The deposition was electrochemically generated by local pH enhancement. The influence of temperature, nitrate ions concentration and flow rate on the nucleation growth process was studied. The electrochemical impedance measurement led the high frequency capacity C-HF to be calculated versus time during the ZnO electrodeposition. As C-HF is proportional to the active surface, the correlation between the current and C-HF evolution was investigated. (C) 2011 Elsevier B.V. All rights reserved.