Electrodeposition and dependency of optical properties on operating voltage and bath temperature of Copper oxide (II) thin films for photovoltaic applications

In our current research, thin films of Copper oxide (CuO) were deposited on copper plate in an electrolytic bath containing CuSO4.5H2O, 3M lactic acid and NaOH by electrodeposition process. CuO thin films were electrodeposited at different voltage and different temperature whereas bath concentration, pH and time were kept constant. The characterization of the CuO thin films deposited at different electrodeposition conditions were conducted by Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS). The SEM study showed the grain sizes of CuO thin films decreased at more negative potentials. Film thickness with regards to voltage and temperature are analysed. Absorption spectrum was obtained from UV-Vis absorption spectroscopy. Subsequently, the optical band gap was determined from their absorption spectrum by using Tauc´s equation. It was found that CuO thin films deposited at low voltage have lower band gap than that of films deposited at higher voltage due to crystalline, uniform and compact grains. The band gap decreases with increasing operating temperature.