Magnesium hydroxide thin films are deposited using cathodic electrochemical deposition, with different concentration of copper as catalyst. The influences of deposition variables on film composition and structural, morphological, and optical properties are investigated. The optical transmission is larger than 90% in the visible range. X-ray photoelectron spectroscopy results indicate fabrication of Mg(OH)(2) films. X-ray diffraction results show that the films are amorphous. All the deposited films show an n-type behavior, with photoelectrochemical characterizations. Electrical conduction is clearly observed for the films with resistivity between 10(3) and 10(4) Omega cm. Thus, transparent Mg(OH)(2) films with n-type conductivity are electrochemically deposited with Cu added as catalyst in the solution.