STRUCTURAL AND OPTICAL PROPERTIES OF COPPER - DOPED COBALT OXIDE THIN FILMS PREPARED BY SPRAY PYROLYSIS

Copper - doped cobalt oxide (Cu:Co 3 O 4 ) films have been prepared by spray pyrolysis (SP) method onto glass substrate at (350)  C with different copper doping concentrations (0%, 1%, 3%, 5%, 7%, 9%) M. Structural and optical properties of the films were studied by X - ray diffraction (XRD) and u ltraviolet (UV - Visible) transmission spectra. The X - ray diffraction results revealed that the films consist of Co 3 O 4 phase with perfect orientation (111) crystallite size variation with increasing Cu doping concentration (34.92, 34.02, 30.87, 30.81, 32.35, 34.04)nm respectively, and lattice constant was (8.065, 8.0668, 8.0692, 8.074, 8.0854, 8.0546)A  . It is found from optical measurements that the transmition is inversely proportional with concentration, the absorption coefficient (α) at the fundamental ab sorption region was determined using the spectra data of transmittance. The tow allowed direct energy gaps were varied between (1.4 to 2.06) eV and they are decreasing with increasing the doping concentration. While the two indirect energy gaps were decrea se as doping concentrations were increased with variation between (1.2 to 1.9) eV.