Facile Route to the Controlled Synthesis of Tetragonal and Orthorhombic SnO₂ Films by Mist Chemical Vapor Deposition

Two types of tin dioxide (SnO₂) films were grown by mist chemical vapor deposition (Mist-CVD), and their electrical properties were studied. A tetragonal phase is obtained when methanol is used as the solvent, while an orthorhombic structure is formed with acetone. The two phases of SnO₂ exhibit different electrical properties. Tetragonal SnO₂ behaves as a semiconductor, and thin-film transistors (TFTs) incorporating this material as the active layer exhibit n-type characteristics with typical field-effect mobility (μ_FE) values of approximately 3-4 cm²/(V s). On the other hand, orthorhombic SnO₂ is found to behave as a metal-like transparent conductive oxide. Density functional theory calculations reveal that orthorhombic SnO₂ is more stable under oxygen-rich conditions, which correlates well with the experimentally observed solvent effects. The present study paves the way for the controlled synthesis of functional materials by atmospheric pressure growth techniques.