Post Thermal Annealing Effect on the Optical Properties of SnO2 Films Prepared by Electron Beam Evaporation Technique

Abstract

This work reports on the effect of post thermal annealing on the optical properties of SnO2 films. The films were deposited using electron beam evaporation technique. The films were annealed in air in the temperature range 200-550 oC. It was found that the annealing temperature has a significant effect on the optical properties of these films. The films are transparent in the visible region with average transmission of 83%. A high optical energy-gap of 3.65 eV was achieved at temperature 500 oC. Many optical parameters such as: refractive index; extinction coefficient; degree of inhomogeneity; dielectric constants; single oscillator energy; dispersion energy; oscillator strength; average oscillator wavelength; static dielectric constant; high frequency dielectric constant; thermal emissivity and optical resistivity were calculated as a function of annealing temperature. Finally, SnO2 films can be used in transparent heat mirror coatings applications due to their low thermal emissivity at high annealing temperature.