Control of Cu2O Film Morphology Using Potentiostatic Pulsed Electrodeposition

The formation of Cu2O films from an alkaline copper-lactate electrolyte using potentiostatic pulse electrodeposition has been conducted. The effects of the frequency, duty cycle, potential amplitude and electrolyte composition during pulsed electrodeposition on the resulting Cu2O morphology, crystal structure and orientation have been investigated in detail. Comparisons are made with films produced by potentiostatic DC deposition in the same electrolyte. An increase in the pulse frequency or reduction in the duty cycle causes the Cu2O grains to become less cubic and more spherical as the crystal growth in the 〈111〉 direction becomes less dominant and growth in the 〈100〉 direction becomes more favored. Higher Cu(II) concentration, lower electrolyte pH and smaller cathodic overpotential have a similar effect and leads to the formation of Cu2O crystals with distinct or truncated octahedral shapes through pulsed electrodeposition. Overall, the application of a pulsed potential waveform during Cu2O electrodeposition in alkaline electrolyte enables the formation of Cu2O films with controllable morphology with lesser need to alter the electrolyte composition or temperature.