Iridium oxide films obtained by thermo-chemical transformation

Films of iridium oxide were deposited by the dipping method from a 0.005M Iridium chloride solution in iso-propanol and post-annealed at different temperatures (350, 450 and 550 °C). After three dippings, very thin films, with effective thickness less than 10 nm were obtained. Their effective refractive index at 632.8 nm wavelength changed from 2.495 up to 2.727. X-ray diffraction measurements proved that composite films formed by an amorphous fraction, rutile IrO₂ phase and metallic Ir particles were obtained. AFM images depict a textured surface, mainly for the highest annealing temperature. The Raman and FTIR spectra confirm the rutile phase of iridium oxide as an important component of the films. A possible path for the film formation is proposed.