Study of the physical properties of polycrystalline thin films of CdO deposited by a chemical bath

Polycrystalline thin films of CdO were prepared by chemical bath deposition using aqueous solutions containing cadmium chloride, amonniunn hidroxide and hidrogen peroxide. The X-ray diffract:ion studies and IR-transmitance measurements reveal that the as-grown material is amorphous or polycrystalline depending upon the growing temperature. Polycristalline as-grown material is cubic cadmium peroxide oriented preferentially in the (011) direction containing free hidroxide and amonnia ions, After annealing at temperatures higher than 200 degrees C, the polycristalline as-grown films become cadmium oxide free from hidroxide and amonnia, ions. These films crystallize in the NaCl structure with the same preferential orientation of the as-grown material, Hall measurements indicated that the annealed polycristalline films had an N type conductivity with an electron concentration around 10(19)cm(-3), and mobilities of the order of 50 cm(2)/Vs. The energy value for direct band-gap, calculated from UV-transmittance data, was about 2.67 eV. In addition, in the low energy range it was possible to observe indirect transitions with a characteristic energy of the order of 1.09 eV. This value. is in good agreement with the theoretical value reported previously by other researchers.