Structural stability of indium oxide films deposited by spray pyrolysis during thermal annealing

The results of the analysis of In2O3 film properties' stability during thermal annealing in the temperature range from 500 to 1100 °C are presented in this article. In2O3 films were deposited by spray pyrolysis from 0.2 M InCl3-water solution. Annealing was carried out in the atmosphere of usual air. The change of parameters, such as film morphology, grain size, texture, intensity of cathodoluminescence, and Raman scattering, was controlled. For structural analysis of tested films, we used X-ray diffraction, scanning electron microscopy, and Atomic force microscopy techniques. It was determined that the change of In2O3 film structure during thermal treatment in oxygen-containing atmosphere goes through the following four standard stages of structure transformation of polycrystalline materials: the stage of structural stability of the film (25-500 °C); the stage of coalescence of grains forming agglomerates (500-700 °C); the stage of local structural reconstruction (700-1000 °C); and the stage of global (comprehensive) structural reconstruction (>1000 °C). The influence of grain size (10-60 nm), film thickness (20-400 nm), and deposition parameters (Tpyr=390-520 °C) on structural stability of In2O3 films is discussed as well.