Optical and electrical properties of tin oxide-based thin films prepared by streaming process for electrodeless electrochemical deposition

摘要

Transparent conducting thin-films of SnO_2: F were grown on preheated glass, Al_2O_3 coated glass, and quartz substrates by Streaming Process for Electrodeless Electrochemical Deposition (SPEED). Stannic chloride (SnCl_4) and ammonium fluoride (NH_4F) dissolved in a mixture of deionized water and organic solvents were used as precursors. The preheated substrate temperature was varied between 440 and 500 °C. High quality SnO_2:F films were grown at all the substrate temperatures studied The resulting typical film thickness was 250 nm. X-ray diffraction shows that the grown films are polycrystalline SnO_2 with a tetragonal crystal structure. The average optical transmission of the films was around 93% throughout the wavelength range 400 to 1000 nm. The lowest electrical resistivity achieved was 6 × 10~(-4) Ω-cm. The Hall measurements showed that the film is an n-type semiconductor, with carrier mobility of 8.3 cm~2/V-s, and carrier concentration of 1 × 10~(21) cm~(-3). The direct bandgap was determined to be 4.0 eV from the transmittance spectrum.