Annealing temperature investigation on electrodeposited Cu2O properties

Thin films of Cu2O were deposited on ITO glass substrates by using the electrodeposition method. The prepared samples were annealed at different temperatures range varying from 200 to 350 degrees C. Chemical, structural and optical properties of samples were studied using XRD, Raman spectroscopy, U-V-visible and photoluminescence spectroscopies. The results revealed that all samples at temperatures lower than 300 degrees C are mainly single cubic Cu2O phase. However, after increasing the annealing temperature to 350 degrees C, Cu2O films are partially oxidized and contain two phases of Cu2O and CuO. Raman results agree with the crystallite size results where the intensity of Raman peaks increases simultaneously with increasing grain size. The optical measurements showed that the band gaps values of the electrodeposited samples increase from 2.12 to 2.24 eV. Two optical gaps were observed at 1.58 and 2.26 eV for the sample annealed at 350 degrees C which confirms the presence of two phases CuO and Cu2O.