Dependency of the band gap of electrodeposited Copper oxide thin films on the concentration of copper sulfate (CuSO4.5H2O) and pH in bath solution for photovoltaic applications

In this study, Copper oxide thin films were deposited on copper plate by electrodeposition process in an electrolytic bath containing CuSO₄.5H₂O, 3M lactic acid and NaOH. Copper oxide films were electrodeposited at different pH and different concentration of CuSO₄.5H₂O and the optical band gap was determined from their absorption spectrum which was obtained from UV-Vis absorption spectroscopy. It was found that copper oxide films which were deposited at low concentration of CuSO₄.5H₂O have higher band gap than those deposited at higher bath concentration. The band gap of copper oxide films also significantly changes with pH of the bath solution. It was also observed that with the increase of the pH of bath solution band gap of copper oxide film decreased.