A Bi-doped ZnO layer was prepared by means of electrodeposition. The lattice structure of the deposits examined by grazing-incidence X-ray diffraction showed a ZnO wurtzite structure without impurity phases [metallic Zn, Bi, or Zn (OH)(2)]. It was found that the surface morphology, Bi content, and electrical property of the deposits were strongly dependent on deposition conditions, such as bath composition, applied potential, and even the counter electrode used (Pt-coated Ti gauze or Zn sheet). The Bi content in the deposits is 0.09 - 1.58 atom % Bi as determined by inductively coupled plasma atomic emission spectroscopy. The sheet resistance of the deposit with Bi content 1.58 atom % exhibited a 4 order of magnitude improvement compared to that of undoped ZnO. By X-ray photoelectron spectroscopy it was found that Bi in ZnO matrix is in a mixed state of Bi-0 (26%) and Bi3+ (74%), which contributes to the defect chemistry for better electric conduction. The 1.58 atom% Bi-doped ZnO layer exhibited p-type conduction with carrier concentration and mobility equal to 1.18 x 10(17) cm(3) and 32.7 cm(2) V-1 s(-1), respectively. (c) 2007 The Electrochemical Society.