Ellipsometric study of ZnO/Ag/ZnO optical coatings: Determination of layer thicknesses and optical constants

Variable angle of incidence spectroscopic ellipsometry was used to study the ZnO/Ag/ZnO (dielectric-metal-dielectric) optical coatings. As a result, the three layer thicknesses, the optical constants of the ZnO layers (3000-8000 W), and the optical constants of the Ag layers (3500-8000 Å) measured on three coated glass samples are reported here. The thickness measurements obtained by ellipsometry agreed with those determined from cross sectional TEM photos well within the error margins of the two techniques. In addition, the spectral dependence of the index of refraction of the silver layers were characterized by oscillations absent in the bulk silver optical data, and likely due to the generation of surface and bulk plasmons.