Abstract
Single phase Cu2O films have been prepared via an electrodeposition technique onto ITO glass substrates at room temperature. Likewise, Cu2O films were deposited using a potentiostatic process from an alkaline electrolyte containing copper (II) nitrate and 1 M sodium citrate. Single phase Cu2O films were electrodeposited at a cathodic deposition potential of -500 mV for a reaction period of 90 min, and pH of 12 to yield a film thickness of 0.49 mu m. The mechanism for nucleation of Cu2O films was found to vary with deposition potential. Applying the Scharifi<er and Hills model at -500 and -600 mV to describe the mechanism of nucleation for the electrochemical reaction, the nucleation mechanism consisted of a mix between instantaneous and progressive growth mechanisms at -500 mV, while above -600 mV the growth mechanism was instantaneous. Using deposition times from 30 to 90 min at -500 mV deposition potential, pure Cu2O films with different microstructures were electrodeposited. Changing the deposition time from 30 to 90 min varied the microstructure from cubic to more complex polyhedra. The transmittance of electrodeposited Cu2O films ranged from 20 to 70% in visible range, and samples exhibited a 2.4 eV band gap. The electrical resistivity for electrodeposited Cu2O films was found to decrease with increasing deposition time from 0.854 x 10(5) Omega-cm at 30 min to 0.221 x 10(5) Omega-cm at 90 min without any thermal treatment following the electrodeposition process. (C) 2016 Elsevier B.V. All rights reserved.