Influence of Annealed Temperature on Optical Properties of Nanostructured CdO Thin Films

Abstract

Nanostructures of cadmium oxide (CdO) thin films were deposited by sol-gel dip coating technique on glass and Si substrates. X-ray diffraction patterns and selected area electron diffraction patterns confirmed the nanocrystalline cubic CdO phase formation. Transmission Electron Micrograph (TEM) of the film revealed the manifestation of nano CdO phase with average particle size lies in the range 1.6 nm to 9.3 nm. From the measurements of transmittance spectra of the films the direct allowed bandgap values have been calculated and they lie in the range 2.85 eV to 3.69 eV with high transparency (~ 75% in the wavelength range 500 -800 nm) of the film. Particle size have also been calculated from the shift of bandgap from that of bulk value for those films for which the particles are compearable to Bohr exitonic radius.