(Cu, Fe, Co, or Ni)-doped tin dioxide films deposited by spray pyrolysis: doping influence on film morphology

摘要

The results of structural characterization of SnO₂ films doped by impurities such as Fe, Cu, Ni, and Co during spray pyrolysis deposition from 0.2 M SnCl₄–water solutions are presented. The change of parameters such as film morphology, the grain size, texture, and the intensity of X-ray diffraction peaks were controlled. For structural analysis of tested films, we used X-ray Diffraction, Scanning Electron Microscopy, and Atomic Force Microscopy techniques. It was shown that the doping promoted the change of the film morphology and the decrease of the SnO₂ grain size; however, these changes were not great. The doping influence becomes apparent more obviously for thin films and the films deposited at low temperatures (T _pyr ∼ 350 °C). At higher pyrolysis temperatures (T _pyr ∼ 450 °C), the influence of the doping on both the grain size and the film morphology was weakened. We concluded that used additives had dominant influence on the structural properties of SnO₂ at the initial stages of the film growth, as well as at the stages of twinning and agglomeration of the SnO₂ crystallites. It was shown that the increase in the contents of the fine dispersion phase in as-deposited film is an important consequence of the SnO₂ doping.