A photoelectrochemical investigation of the n- and p-type semiconducting behaviour of copper(I) oxide films

Copper(I) oxide films were prepared on copper substrates by exposing them to solutions containing Cu2+ ions, and it was observed that the photoresponse of these films electrodes in a photoelectrochemical cell is both n- and p-type. However, it was observed that the n-type behaviour of these film electrodes could be enhanced and the p-type behaviour could be reduced by adjusting the pH of the solution in which the oxide films had been prepared. The simultaneous existence of spatially separated n- and p-type regions in the Cu2O film is suggested as the possible reason for these observations. The anodic oxidation of copper was considered to be the origin of the p-type regions while the n-type regions were considered to be the result of the cathodic deposition of Cu2O.