Electrochemical deposition of ZnO film and its photoluminescence properties

ZnO thin films were prepared by the electrochemical deposition method on conductive substrates. The as-deposited film was ZnO crystallites of the wurzite structure highly oriented along the (0 0 2) plane. The specific crystalline morphology may be attributed to the growth mechanism through the orientation attachment mode, which is one of the characteristics peculiar for the present process, because the terrace has been clearly observed in high-resolution AFM images. The film shows high transmittance and an optical band gap energy of 3.3 eV. After annealing in N2 or Ar, strong green emission was observed, which should be related to the generation of singly ionized oxygen defects. Improving emission intensity further by optimizing the annealing conditions, this method may be promising to replace the traditional method for preparation of ZnO green phosphor.