Studies on optical properties of antimony doped SnO₂ films

Highlights: • Antimony doped tin oxide thin films were grown by spray method on glass substrates. • The antimony doping was varied from 0 to 4 at%. • The structural properties of the films were investigated by X-ray diffraction method. • A simple analysis according to Swanepoel's method was applied to derive the real and imaginary parts of the complex index of refraction plus film thickness. • The dispersion of refractive index was investigated in terms of the single-oscillator Wemple and DiDomenico model to determine the optical parameters. - Abstract: Antimony doped tin oxide thin films were grown by spray method on microscope glass substrates. The antimony doping was varied from 0 to 4 at%. The structural properties of the films were investigated by X-ray diffraction method. The optical transmittances of thin films were measured with UV-Vis-NIR spectrometer in the 300–2000 nm wavelength range. A simple analysis according to Swanepoel's method was applied to derive the real and imaginary parts of the complex index of refraction plus film thickness. The dispersion of refractive index was investigated in terms of the single-oscillator Wemple and DiDomenico model and the important oscillating parameters such as the dispersion energy E_d, the oscillation energy E_o, the high frequency dielectric constant ε_∞ were determined. The analysis of the refractive index has been carried out to calculate the lattice dielectric constant ε_L and the ratio of carrier concentration to the effective mass N/m*. The real and imaginary parts of the electronic dielectric constant and optical conductivity were analyzed. The optical band gap, E_g values of the films were obtained from the spectral dependence of the absorption coefficient, using the Tauc relation.