REFRACTIVE-INDEXES OF THE TUNGSTEN-OXIDE FILMS PREPARED BY SOL-GEL AND SPUTTERING PROCESSES

Tungsten oxide films were prepared by sol-gel and sputtering processes . The refractive indices and extinction coefficients of the films were calculated from the transmittance and reflectance spectra in the visi ble and infrared regions, The films were transparent in the visible an d infrared regions when they were prepared by the sol-gel process and fired at 300 degrees C and 500 degrees C, and by the sputtering proces s under the conditions of O-2/Ar=0.05 and 0.1 at room temperature. The refractive indices of the films depended on preparation conditions. T he extinction coefficients of the films were almost zero in the visibl e and infrared regions. On the other hand, film prepared by the sputte ring process under the condition of O-2/Ar=0.01 was blue colored, The refractive index of the film increased with increasing wavelength in t he visible and infrared region. The extinction coefficient of the film showed a large value at 1450 nm, which corresponds to the minimum of the transmittance spectrum of the film.