Characterization and study of high conductivity antimony-doped tin oxide thin films grown by mist chemical vapor deposition

Abstract

Antimony doped tin oxide thin films are grown at atmospheric pressure using a home-built mist chemical vapor deposition system, which is an environmental-friendly technique with low energy consumption. For obtaining high quality Sb:SnO_x films, different solutions are used to support the film fabrication process. The role of each component in supporting solution is also preliminarily analyzed and studied. In this work, the growth rate, density, transmittance, hall effect, conductivity, surface morphology, crystallinity, component and chemical states of Sb:SnO_x films are investigated. Sb:SnO_x films prepared at 400 °C using a mixing solution of H₂O, HNO₃ and HCl show a low electrical resistivity of 6.58 × 10⁻⁴ Ω cm, high carrier concentration of 3.26 × 10²¹ cm⁻³, high transmittance of 90%, and wide optical band gas of 4.22 eV. X-ray photoelectron spectroscopy analyses disclose that the samples with good properties have high [Sn⁴⁺]/[Sn²⁺] and [O–Sn⁴⁺]/[O–Sn²⁺] ratios. Moreover, it is discovered that supporting solutions also affect the CBM–VBM level and Fermi level in the band diagram of thin films. These experimental results confirm that Sb:SnO_x films grown using mist CVD are a mixture of SnO₂ and SnO. The sufficient supply of oxygen from supporting solutions leads to the stronger combination of cations and oxygen, and the combination of cations and impurities disappear, which is one of the reasons for obtaining high conductivity Sb:SnO_x films.