Electrodeposition and characterization of nanocrystalline cuprous oxide thin films on TiO2 films

The grain size in cuprous oxide (Cu2O) thin films is a key to improve the performance of solar application devices. In this paper, electrochemical deposition of nanocrystalline Cu2O thin films on TiO2 films coated on transparent conducting optically (TCO) glass substrates by cathodic reduction of cupric acetate has been investigated. The deposition kinetics of nanocrystalline Cu2O thin films were studied and the parameters limiting the deposition of the films were determined. Pure Cu2O deposited at bath temperature between 0 and 30 °C produced spherically shaped grains with 40∼50 nm diameters which have not been reported previously. The effect of pH was studied and a solution with a pH between 5.5 and 6 was found to be best. The effect of annealing on bulk structure, electrical resistivity, and optical absorption of nanocrystalline Cu2O thin films was also studied and the results were discussed.