Thin films of Al 2 O 3 were prepared by the sol–gel process. Dip-coating technique was used for deposition of the Al 2 O 3 thin films onto glass substrates. Optical and structural properties of the films were investigated with respect to the annealing temperature (100–500°C). The structure of these films was determined by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was performed for the analysis of surface morphology. For determination of the optical constants of Al 2 O 3 thin films, UV-Visible spectrophotometry measurements were carried out. Annealing temperature affects the structural and optical properties of the Al 2 O 3 thin films. The refractive index and extinction coefficient of the films at 550 nm wavelength increase from 1.56 to 1.66, and from 3.41 × 10-5 to 5.54 × 10-5, respectively while optical band gap and thickness of the films decrease from 4.15 eV to 4.11 eV, and 360 nm to 260 nm, respectively, by increasing annealing temperature from 100°C to 500°C.
Effect of Annealing Temperature on Structural and Optical properties of Mn doped SnO2 Thin Films Prepared by Sol-Gel Technique