A comparative study of the optical properties of zirconia thin films prepared by ion-assisted deposition

Abstract

Thin films of zirconia have been prepared using ion-assisted deposition over a wide range of ion energies from 0 to 700 eV and their optical properties such as refractive index and absorption investigated. The ions were produced using two different ion sources: (1) a Heitmann-type low energy source; (2) a Kaufman-type broad beam ion source to produce ions in the energy range 100–700 eV. It was observed that the refractive index value increased with increasing ion energy. However, the extinction coefficient showed lower values at lower energies than at higher energies. A bulk-like value of 2.2 for the refractive index at a wavelength of 650 nm has been obtained at 500eV energy. The absorption at this energy is fairly high (0.008), but films with negligible absorption have been obtained at lower energies.