Electrical, structural and optical properties of SnO2 thin films prepared by spray pyrolysis

This study investigated the effect of the substrate temperature on the structural, optical, morphological, and electrical properties of undoped SnO2 films prepared by a spray deposition method. The films were deposited at various substrate temperatures ranging from 300–500 °C in steps of 50 °C and characterized by different optical and structural techniques. X-ray diffraction studies showed that the crystallite size and preferential growth directions of the films were dependent on the substrate temperature. These studies also indicated that the films were amorphous at 300 °C and polycrystalline at the other substrate temperatures used. Infrared and visible spectroscopic studies revealed that a strong vibration band, characteristic of the SnO2 stretching mode, was present around 630 cm−1 and that the optical transmittance in the visible region varied over the range 75–95% with substrate temperature, respectively. The films deposited at 400 °C exhibited the highest electrical conductivity property.