Electrochemical deposition of copper oxide nanowires for photoelectrochemical applications

We report a two-step electrochemical process to grow copper oxide nanowires without the use of templates and surfactants. The first step is to electrochemically corrode amorphous Cu-W oxides pre-sputtered on fluorine-doped tin oxide (FTO) coated glass substrates under positive potentials. The second step is to use the corroded samples to grow copper oxide nanowires electrochemically under negative potentials. We find that copper oxide nanowires grown by this method exhibit excellent contact with the FTO-coated substrates leading to good charge transfer. The oxidation states, i.e., CuO or Cu2O, and morphology of nanowires can be controlled by the applied potentials. Cu2O nanowires grown using this method reveal moderate photoelectrochemical response and stability under illumination and under cathodic bias.