Influence of Applied Potential on The Structural and Optical Properties of Cu2O Thin Films Grown by Electrochemical Deposition

Abstract

Cu₂O thin films have been deposited on indium-tin-oxide (ITO) coated glass substrate by electrochemical method or electrodeposition. The effect of deposition potential on the microstructure and optical properties of Cu₂O thin films was studied. Electrodeposition for two Cu₂O thin films was carried out at –0.5V and –0.6V relative to the standard calomel electrode (SCE) as a reference electrode. Cu₂O thin films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and UV-Visible spectroscopy. The diffraction pattern indicated the cubic structure of the Cu₂O crystal has been well grown. The lattice parameters of Cu₂O films slightly increased as the potential of electrodeposition increased. The crystallite size of Cu₂O films significantly increased as the applied potential increased. Cu₂O thin films showed a smooth and flat surface morphology based on SEM images. The optical transmittance of the Cu₂O thin films drastically decreased as the applied potential increased due to the film thickness increasing. The bandgap energy of Cu₂O films based on the Tauc plot increased as the applied potential increased, that is 2.0 eV for the film deposited at -0.5V and 2.13 eV deposited at -0.6V.