Cu2O: Electrodeposition and characterization

Well-defined polycrystalline Cu2O was electrodeposited on transparent condu cting substrates from alkaline Cu(II) lactate solutions. The morphology of the layers could be controlled by choosing the appropriate experimental con ditions; the pH and temperature of the deposition solution were especially important. The growth of the oxide involves a thermally activated process, for which an activation energy of 0.8 eV was found. A mechanism for the dep osition is proposed. The optical absorption of the electrodeposited oxide i n the visible range was much weaker than expected for a direct semiconducto r with a band gap of 2.0 eV. Finally, we show that it is possible to grow C u2O inside an n-type TiO2 nanoporous matrix.