Deposition of thin films of cobalt oxides by MOCVD

The Co(hfa)(2).2H(2)O (hfa = CF3C(O)CHC(O)CF3) precursor was used in MOCVD experiments to deposit cobalt oxides, on optically transparent SiO2 substrates. CoO and Co3O4 films have been obtained depending on the adopted deposition conditions. XRD measurements provided evidence that CoO consists of cubic, (100) oriented crystals, whilst Co3O4 films are only partially oriented along the (311) direction. Mean crystallite sizes were evaluated from the XRD line broadening and the band-gap for Co3O4 was determined from the optically induced transitions. Both optical spectra and resistivity measurements of Co3O4 thin films showed that they are semi-conducting. The surface structure of the films was investigated by XPS.