Fabrication and characterization of Cu₂O/TiO₂thin film heterojunction with chemical bath deposition

In this study, heterojunction n-TiO2/ p-Cu2O has been fabricated. TiO2 was coated on FTO glass followed by Cu2O deposition by the chemical bath deposition method. In order to determine the effect of thickness on optical properties, as-annealed Cu2O thickness was varied, i.e. 10 cycles, 20 cycles, and 50 cycles. The physical properties of the copper oxide films were measured by an X-ray diffraction (XRD), a scanning electron microscope (SEM), a thermogravimetry analysis (TGA), and a UV-Vis spectroscopy. The XRD pattern of Cu2O showed almost pure Cu2O with some traces of CuO. The morphology of obtained Cu2O after 50 cycles indicated two distinguished morphologies, namely small edge- and corner truncated octahedra and larger all-corner truncated rhombic dodecahedra. While the selected annealing temperature was found withn the range of stable Cu2O. An increase in thickness as the cycles applied was calculated, but it resulted in no significant change in optical band gap.