Temperature-dependent optical dispersion of composite oxide multi-layers

Characterizing thin-film materials with high refractive index, high thermal stability and infrared transparency is important for designing thermophotovoltaic (TPV) selective emitters and thermal barrier coatings (TBCs). Here, we report spectroscopic ellipsometer measurements of several thin films in the wavelength range 210 nm to 2500 nm from room temperature to 1000 deg C. Our findings provide insights into the potential impacts of temperature change on the aforementioned applications, induced by the underlying changes in their electronic band structures. In the first step, we present the properties of magnesium oxide and strontium titanate substrates. Next, we consider layers of cerium oxide and barium zirconate deposited on top of these substrates. Finally, we apply these initial characterizations to understand data obtained from multilayer samples comprised of a combination of layers from all these materials, and project the potential performance for TPV and TBC applications.