Surface Profile and Optical Properties of Sb-doped SnO2 Thin Films

Tin oxide (SnO₂) and antimony-doped tin oxide (SnO₂:Sb) thin films were deposited on the microscope slide glass substrates by sol-gel dip coating technique. Precursor solution was prepared using tin(IV) chloride pentahydrate, antimony chloride, urea, and hydrochloric acid. The Sb dopant concentration was varied from 1 to 4 mol% to investigate the effect of doping on the optical and surface roughness of the films. AFM image showed that undoped films having a very smooth surface morphology with nanostructure grain size in the range of 37.6 to 56.3 nm. Meanwhile, Sb-doped SnO₂ was more roughness if compared to undoped one. The optical properties of the films have been studied from transmission spectra in the ultraviolet-visible wavelength range. Energy gap of Sb-doped SnO₂ thin films are in the range of 4.07-4.11 eV, shifted to the lower value with increased doping concentration.