The optical and structural properties of sno2 films deposited by sol gel spin coating method

In this work, tin oxide (SnO2) films were deposited onto the glass substrates by using the sol gel spin coating method. The influence of the molarity and the spin speed on the optical and structural properties of the SnO2 films were investigated. The thicknesses of the films were found to be between 120 and 480nm. The thicknesses of the obtained films changed with the molarity and the spin speed. The thickness increased with increasing of the molarity and decreased with increasing the spin speed. The average crystallite size and d% error values were calculated using the XRD patterns of the SnO2 films. The films have a polycrystalline structure. The molarity and the spin speed played an important role on the crystalline structure of the films. The structure of the films changed from orthorhombic phase to tetragonal phase with increasing of the molarity and the spin speed. The optical band gaps of the SnO2 films were determined by using the analysis of optical absorption spectra. The direct allowed optical band gaps of the films were found to be between 3.63 and 4.25eV. The optical band gap tended to decrease with increasing the molarity. The optical constants of the films such as refractive index and dielectric constants were calculated by using the optical measurements.