Optical and structural properties of Fe2O3 thin films prepared by ion-beam assisted deposition

We studied the optical and structural properties of Fe2O3 thin films deposited by conventional evaporation and ion-beam assisted deposition (IBAD). In IBAD, the anode voltage and filament current were varied to investigate the properties of Fe2O3 thin films. It is found that the refractive index of Fe2O3 thin films deposited by ion-beam assisted deposition is higher than that by electron-beam deposition, and Fe2O3 films are more stable and denser after heat treatment. Fe2O3 has a high refractive index as well as a high absorption at short wavelength region among conventional high refractive index materials. Therefore, for a long-wave pass filter, it has an advantage of not only reducing the total number of layers, but also absorbing the short wavelength light. As an application, long-wave pass filters of 12-layers were also fabricated by using electron-beam deposition and ion-beam assisted deposition. The long-wave pass filter by IBAD shows the excellent optical and mechanical properties after annealing. It indicates that the long-wave pass filters using IBAD Fe2O3 thin films can be widely used to the surfaces for high temperature applications.