Influence of annealing treatment on the optical properties and structure of Cd2SnO4 thin films

The optical properties of Cd2SnO4 films were investigated after annealing treatment. Cd2SnO4 thin films on glass substrates were prepared by r.f. reactive sputtering from Cd–Sn alloy target in an Ar–O2 atmosphere. The films obtained were characterized by scanning electron microscopy, X-ray diffraction and optical transmission spectra. The experimental results showed that the post-deposition annealing treatment has a significant influence on the properties and structure of the films. The transmittance and optical gap energy were increased with increasing annealing temperature. These results can be explained by the changes in the oxygen vacancies and the Burstein shift effect of Cd2SnO4 films.