Evolution of the optical and structural properties in ZnS/MgS₂ multilayers as the number of layers increases

A multiple sample holder has been designed to obtain multilayer samples of ZnS and MgF₂, with different numbers of layers in the same evaporation process. The grown samples were optically analysed by measuring the transmittance in the Vis-NIR range, from where the complex refractive index is extracted by using a parametric program of fitting. The properties of the multilayers have been studied in relation to the number of layers, and also in relation to the first deposited layer material on the substrate. It has been found that the transmittance minimum diminishes and goes to higher wavelengths as the number of layers increases. Also, variations on the structure of both ZnS and MgF₂ materials were observed by x-ray diffraction, and were correlated with the number of layers of the sample.