Structural, electrical and optical studies on chemically deposited tin oxide films from inorganic precursors

Two inorganic tin compounds SnCl4·5H2O and SnCl2·2H2O were used to prepare highly oriented undoped tin oxide (SnO2) thin films. By spray pyrolysis, ethanolic solution of SnCl4·5H2O and SnCl2·2H2O led to the deposition of (2 0 0) and (1 1 0) oriented SnO2 films, respectively. Microstructural parameters, electrical and optical properties of these films as a function of substrate temperature are reported. The films deposited at optimum deposition conditions have 170 nm thickness and exhibited a resistivity of 29.2 × 10−6 Ωm along with refractive index 2.03 at 550 nm. The analytical expressions enabling the derivation of the optical constants of these films from their transmission spectrum only have successfully been applied. Finally, the refractive index dispersion is discussed in terms of the single-oscillator Wemple and Didomenico model.