Structural and optical properties of Ga-doped CdO nanocrystalline thin films

In the present work, a systematic study has been carried out to understand the effect of gallium doping on the various properties of the CdO nanocrystalline thin films. Ga-doped CdO nanocrystalline thin films with different gallium concentrations (0.01 M, 0.03 M, 0.05 M, 0.07 M and 0.09 M) have been synthesized by sol-gel method. The X-ray diffraction (XRD) patterns show that the CdO and Ga-doped CdO films exhibit cubic structure. The chemical composition of the Ga-doped CdO films was studied using X-ray photoelectron spectroscopy (XPS). XPS results clearly showed the existence of Ga as a doping element in the CdO crystal lattice. Optical absorption spectra of Ga-doped CdO films shows that absorption edge is slightly shifted toward longer wavelength side (red shift) when compared to that of CdO. The optical band gap of CdO film was found to decrease with increasing Ga-doping concentration.