Effect of post-annealing temperature on structural, morphological, optical, and electrical properties of Sb-doped SnO₂ thin films for optoelectronic applications

Antimony(Sb)-doped tin oxide (SnO2) thin films were grown by sol-gel spin coating and post-annealed from 150 to 350 °C. XRD, FESEM, AFM, XPS, UV-VIS-NIR spectroscopy, and four-point probe technique were used to study the physical properties of Sb-doped SnO2 (ATO) films. XRD studies of Sb-doped SnO2 films exhibit a tetragonal rutile structure. The crystallite size of ATO films increased from 19 to 45 nm with post-annealing temperature. The morphology of ATO films shows a dense structure with a homogeneous grain distribution. The optical bandwidth of Sb-doped SnO2 films decreased from 3.36 to 3.08 eV due to reduced defect densities and grain boundaries. The electrical resistance of Sb-doped SnO2 films reduces from 2.64×10-3 to 1.74×10-3 Ω.cm due to improved crystallinity and decreased interstitial atoms with increased post-annealing temperature.