Charge transfer in copper oxide thin films deposited at different electrodeposition potential

The deposition potential affects the structural, morphological, optical, and electrochemical impedance spectroscopy properties of cuprous oxide (Cu₂O) thin films formed on copper (Cu) substrates adopting a three-electrode electrochemical deposition procedure. XRD data revealed that the deposited films have a cubic structure established with desired (111) growth orientation. Scanning electron microscopy (SEM) images reveal that Cu₂O film has very well three-sided pyramid-shaped grains which are equally spread over the surface of the Cu substrates and change substantially when the plating potential is changed. The photo-current density of prepared Cu₂O thin films was increased from −1.41 × 10⁻⁴ to −3.01 × 10⁻⁴ A/cm² with increasing the deposition potential of −0.3 to −0.6 V, respectively. Further, Cu₂O thin films obtained at −0.6 V have the minimum charge transfer resistance (R_ct) than Cu₂O thin films synthesized at −0.3 to −0.5 V, suggesting that Cu₂O thin films produced at −0.6 V have the highest electron transfer efficiency.