Optical properties of zinc-iridium oxide thin films

We present the results of an investigation of ultraviolet, visible, near-infrared (UV-Vis-NIR) and X-ray absorption spectroscopy absorption spectra for zinc-iridium oxide (Zn-Ir- O) thin films with various iridium concentrations deposited by reactive DC magnetron sputtering. It is found that the absorption spectra of zinc-iridium oxide thin films contain a broad band with maxima at 446 nm and 710 nm in the visible region, bands with maxima at about 1100 nm and 3300 nm, and a low-intensity absorption band at 1570 nm in the near-infrared region. The obtained absorption bands are associated with iridium ions at valences of Ir³⁺, Ir⁴⁺ and Ir⁵⁺. Changes in the oxidation state of iridium ions from 5+ to 4+ are observed.