Photoelectrochemical Behavior of Electrodeposited CuO and Cu[sub 2]O Thin Films on Conducting Substrates

Cuprous oxide has been prepared by the photoelectrochemical reduction of a CuO film formed on a conducting substrate by the anodic deposition from an alkaline solution of a Cu(II)-amino acid complex. Both copper oxide films thus prepared are found to be typical p-type semiconductors. The onset of the cathodic photocurrent due to the reduction of on CuO/ITO (ITO, indium tin oxide) and electrodes give positive shifts of about 0.2 and 0.03 V, respectively, from the dark current rises. Optical bandgap energies of CuO films depend on the amino acids used, 1.56 (glycine), 1.40 (alanine), 1.38 (isoleucine), 1.38 eV (valine), and the value of for the film is 2.17 eV. The relationship between the flatband potential and the pH for CuO and films are both linear with the slope of about −60 mV/pH in agreement with the Nernstian expression for the of a semiconductor. © 2004 The Electrochemical Society. All rights reserved.