Impact of substrate temperature on the physical properties of (222) oriented CdIn2O4 thin films by nebulized spray pyrolysis technique

The cadmium indium oxide thin film (CdIn₂O₄) was formed onto a micro glass substrate using the nebulized spray pyrolysis process at substrate temperatures ranging from 350 to 550 °C with a 50 °C interval. The X-ray diffraction investigation revealed the polycrystalline nature of the films with a cubic structure and the preferred orientation along the (222) plane. The optical transmission and optical spectra were obtained using optical analysis and the multiple interference effect was significant in all of these films within the wavelength range of 300–1100 nm. These films were highly adhesive, homogeneous, and shining. Bandgap values ranging from 2.71 to 3.37 eV with direct allowed nature were obtained. The Urbach energy values and skin depth were observed for all the films. The surface ratio of the elements was analyzed using the EDAX spectrum. Scanning electron microscope images exhibited flower-shaped grains. Photoluminescence spectra at room temperature explain the four emission bands in all the samples, such as the sharp dominant peak at 490 nm in the UV–visible region. The electrical parameters were analyzed; the minimum resistivity was 0.51 × 102 Ω cm, and the mobility was 158 cm²/Vs for the film deposited at the substrate temperature of 500 °C.