Formation Process of Antimony-Doped Stannic Oxide Film from Organometallic Compounds by Thermal Decomposition

Abstract

Antimony-doped stannic oxide film was prepared as follows; butanol solution of stannous caprylate containing di-isoamyloxy ethoxy antimony was coated on a glass substrate, and dried at room temperature for thirty minutes. The resultant film was dried at 110° C in a drying oven for thirty minutes, then it was heated in a electric furnace at the temperature up to 200-600° C for twenty minutes. The film formation process was examined by thermogravimetric analysis, infrared spectro-metry, and X-ray diffraction and electron diffraction methods. The effects of the amounts of antimony oxide and coating-heating repetition on the electric resistivity of prepared film was also examined. When a film of organic stannous compound solution was dried at 110° C, it showed an iridescent interference color and an amorphous stannous oxide phase deposited in it. This amor-phous stannous oxide phase change to crystalline stannic oxide phase by heating at 350° C. The higher the antimony oxide content in the film, the higher the changing temperature of stannous oxide to stannic oxide and the deeper the blue color of prepared film. The film became harder by heating at a temperature above 400° C. Surface resistivity of undoped stannic oxide film was about 6 meg-ohm at room temperature showing non-metallic conduction. In the case of the antimony-doped stannic oxide film, however, the surface resistivity was about 5-50 k-ohm at room temperature showing metallic conduction. The resistivity of the latter film was reduced remarkably by the repetition of coating and heating procedure.