Effect of oxidation temperature on the properties of copper oxide thin films prepared from thermally oxidised evaporated copper thin films

Abstract

Copper thin films were deposited on glass substrates using thermal vacuum evaporation at 100 oC substrate temperature and then thermally oxidized in air at varying temperatures of 150 oC, 250 oC, 35 0 oC and 450 oC for 2h each. The structural, electrical, and optical properties of the film are determined using X-ray diffraction (XRD), scanning electron microscopy (SEM), four point probe and UV-visible spectroscopy. The XRD pattern show the formation of fine grain Cuprous Oxide (Cu2O) at 250 oC and Cupric Oxide CuO at 350 and 450 oC. Resistivities were calculated to be 4.1x10-6 Ω-cm, 1.92x10-6 Ω-cm, 1076.76 Ω-cm, 127.51 Ω-cm and 205.16 Ω-cm for the as-deposited and Cu Films oxidised at 150, 250, 350 and 450 oC respectively. The Optical band gap value varied between 1.78 eV and 2.2 eV.