Effects of SiO₂ Barrier and N₂ Annealing on Sb-Doped SnO₂ Transparent Conducting Film Prepared by Sol-Gel Dip Coating

Abstract

The transparent conducting thin film of the ATO (antimony-doped tin oxide) was successfully fabricated on bare glass and SiO₂/glass substrates by the sol-gel dip coating method. Optical transmittance and electrical resistivity for the 400 nm thick ATO thin film on SiO₂/glass annealed under nitrogen atmosphere were 84% and 5.0 × 10⁻³ Ω cm, respectively. The XPS analysis confirmed that SiO₂ buffer layer inhibited Na ion diffusion from the substrate, resulting in prohibiting the formation of secondary phase such as Na₂SnO₃ and SnO and increasing Sb ion concentration and higher ratio of Sb⁵⁺/Sb ³⁺ in the film. It was found that N₂ annealing treatment leads to the reduction of Sn⁴⁺ as well as Sb⁵⁺, however the reduction of Sn⁴⁺ is more effective, and consequently results in a decrease in the electrical resistivity to produce excellent electrical properties in the film.