Effect of substrate temperature on the stress and blue light emission of nanostructured In2O3-F thin films prepared by spray pyrolysis

Nanocrystalline Fluorine-doped indium oxide (IFO) thin films have been deposited with various substrate temperatures by reactive chemical pulverization spray pyrolysis technique onto glass substrates. The effect of substrate temperature (Ts) on the stress and luminescence properties was investigated in detail using X-ray diffraction, transmission, photoluminescence spectroscopy, electrical resistivity and scanning electron microscopy (SEM). XRD analysis confirmed the cubic structure of polycrystalline In₂O₃. The preferred growth orientation along (222) plane shifts to (400) and the compressive stress decreases from 1.20 to 0.11 GPa when the substrate temperature was increased from 400 to 500 °C. The photoluminescence (PL) spectra of (IFO) present two blue and a yellow emission. Intensive blue PL bands at 414 and 436 nm were observed in the samples deposited at 500°C, which present the strongest orientation along (400) peak and a lower resistivity of 1.4 × 10^-2 Q cm. A shift of blue peaks to shorter wavelength of (IFO) films has also been observed with the increase of Ts and this may be attributed to the change of stress present in the films.