Article PreviewArticle PreviewArticle PreviewWe present the results obtained using Cr 2 O 3 as selective absorbing layer on aluminium film substrate. The thin films were deposited by electron beam evaporation using a multiple crucible e-gun able to deposit 4 materials in sequence without breaking the vacuum. Optical characterization of the multilayer films is based on ellipsometry and hemispherical reflectivity. The complex refractive index has been determinate and it has been used to design a selective solar absorber with high absorptance.