Tin dioxide (SnO 2 ) thin films have been deposited using chemical spray pyrolysis on non-conducting glass substrates at temperature 400 o C with different solution concentration from 0.2M to 0.5M.The structural , optical and surface morphological properties of deposited films were studied using scanning electron microscope (SEM), Xray diffraction (XRD), UV-Vis spectrometry techniques. SEM studies reveal that SnO 2 films exhibited the irregular grains over the surface and the amount of grain

more »

... reases with increase in the solution concentration. The XRD studies reveal that films are crystalline and structure of tetragonal phase. Micro structural parameters such as crystallite size, micro strain, and dislocation density are calculated and found to depend on solution concentrations. The optical band gap of SnO 2 thin films is calculated using transmittance and reflectance data using UV-Vis spectrometry. From the data, energy band gap lies between 2.72 eV to 2.95eV. And refractive index of the thin film is decreases with decrease in solution concentration. Refractive index for tin dioxide thin films were evaluated from the transmittance and reflectance measurements and its variation with wavelength are shown in Fig. 5 . From the plot, it is clear that the refractive index decreases with decrease in solution concentration. For all films, the refractive index is found to decrease in the wavelength region 200 nm to 450 nm and thereafter remains more or less constant. The refractive index lies between 1.68 and 1.89 for 0.2 M SnO 2 films and 1.73 and 1.94 for 0.5 M SnO 2 films. This may be due to solution concentration, mobility and coarse surface effect of thin films.