PLASMA OXIDATION OF CU, TI AND NI AND THE PHOTOELECTROCHEMICAL PROPERTIES OF THE OXIDE LAYERS FORMED

Plasma oxidation of Ti, Cu and Ni was carried out using a conventional diode-type glow discharge system. Structural and photoelectrochemical properties of the oxide layers formed were examined. Electron diffrac tion confirmed the formation of a TiO2, Cu2O/CuO, and NiO layer on the Ti, Cu, and Ni surfaces, respectively, after the plasma oxidation. Ph otoelectrochemical solar cells were fabricated using the oxide layers formed as a semiconductor electrode. The TiO2 electrodes showed modera te photoresponse under anodic potentials in a methanol aqueous solutio n, while the Cu2O/CuO and NiO electrodes showed a weak photoresponse u nder cathodic potentials. In conclusion, the TiO2 layers prepared by p lasma oxidation work well as a semiconductor electrode for a photoelec trochemical cell and are stable in methanol solution.