Thin films deposited by Atomic Layer Deposition can have very interesting characteristics. In particular, certain metal oxide films can have significantly different optical properties than the bulk material. Zinc oxide as a UV absorber, for instance, can display characteristics of quantum confinement dependent on the thickness of the film. This allows the user to effectively “tune” the bandgap of the material, based upon the thickness of the zinc oxide film. Similar films can be used for oxidation protection, in the example of alumina films. Both uses have applications in photovoltaics, pigment sciences, and in high-temperature ceramics.