Annealing effects on the properties of copper oxide thin films prepared by chemical deposition

We have investigated the annealing effect on the structural, optical and electrical properties of copper oxide films prepared on glass substrates by chemical deposition. The films were annealed in air for different temperatures ranging from 200 to 350 degrees C. X-ray diffraction patterns showed that the films as-deposited and annealed at 200 and 250 degrees C are of cuprite structure with composition CU2O. Annealing at 300 degrees C converts these films to CuO. This conversion is accompanied by a shift in the optical band gap from 2.20 eV to 1.35 eV. Also this conversion was obtained by the dc electrical conductivity and FTIR spectroscopy measurements.