Synthesis and properties of pure and antimony-doped tin dioxide thin films fabricated by sol–gel technique on silicon wafer

High-quality antimony-doped tin dioxide (SnO2:Sb) thin films with various concentrations of Sb have been prepared on Si (1 1 1) wafer by sol–gel technique. The microstructure, surface morphology, composition and optical properties of the films are characterized using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. It is found that the films are the dominant orientation of (1 0 1) with rutile structure of SnO2, Sb dopant causes the peak positions in XRD patterns to shift slightly instead of introducing new phases, and the average grain size of the films is about 26 nm. Optical constant, refraction index n from 1.55 to 1.95 in the visible spectral region, was determined through multilayer analyses on their respective pseudo-dielectric functions. It is also found that the optical constants depend strongly on the layers of films, annealing temperature and the concentration of Sb dopant.