Effect of heat treatment on the properties of Cd(OH)2 and CdO films grown by chemical bath deposition

Nanostructured cadmium hydroxide (Cd(OH)2) thin films have been fabricated on glass substrates by the chemical bath deposition method and converted into cadmium oxide (CdO) films by heat treatments. Some of the films were studied as-grown and the others were annealed in air at 150, 300 and 450 degrees C. The effects of various annealing processes on the structural, morphological and optical properties of the Cd(OH)2 and CdO films were studied. The band gaps of the films vary from 2.74eV to 2.32eV for different annealing temperatures. It was observed that there is a direct dependence of the structural, morphological and optical properties on the annealing temperature of the films. X-ray diffraction (XRD) measurements showed that as-grown and annealed film at 150 degrees C fully consist of Cd(OH)2 and the annealed films at 300 and 450 degrees C consist of CdO nanoparticles. The size of the nanoparticles, which were calculated from the scanning electron microscopy (SEM) figures by using a pixels program, was found to lie between 460 and 600nm.