Studies on cadmium oxide sprayed thin films deposited through non-aqueous medium

In the present investigation thin films of cadmium oxide (CdO) have been deposited onto the glass substrates by spray pyrolysis technique using 0.2 M non-aqueous solution of the cadmium acetate. Cadmium acetate has been used as a precursor due to its relatively lower decomposition temperature. The films were deposited by using air as a carrier gas with the spray rate of 6 ml min(-1). The films were deposited onto the ultrasonically cleaned glass substrates at different substrate temperatures ranging from 573 to 773 K at the step of 25 K. The X-ray diffraction (XRD) studies show that the films are polycrystalline with preferred orientation along (111) plane. It is further revealed that the films deposited at 623 K show better crystallinity as compared to the films deposited at lower and higher substrate temperatures. The dc electrical resistivity measurement was carried out in the temperature range 300-500K and it is found that films prepared at 623 K substrate temperature exhibit lower resistivity which is complementary to XRD results. Optical absorption studies of the films have been carried out in the wavelength range 350-850 nm and the data were analyzed to determine the band gap energy of the deposited material. The band gap energy is estimated to be 2.31 eV. These results are in good agreement with those reported earlier by others. (C) 2003 Published by Elsevier B.V.