CeO2 | Optical characterization of thin films

CeO2(Cerium Oxide) is a high-index material in the VIS-to-IR region, with a refractive index near 2.2 at 550 nm and a transmittance range from below 400 nm to 12 μm.

It forms a crystalline film in most cases (depending on the deposition conditions), and is superior in chemical and thermal stability. Compared with other high-index materials for the VIS region, this material evaporates at a lower temperature, which reduces the amount of irradiation required to melt it.

However, the following drawbacks have made CeO2 unpopular compared with other high-index materials in the VIS region: Research has indicated that this material requires a very high substrate temperature to overcome some of the irreproducibility in its behavior: inhomogeneity and variations in refractive index during evaporation are commonly observed. In addition, this material has an absorption edge near the UV end of the VIS region (i.e., 400 nm) as well as low film hardness and low resistance to moisture.