Optical properties of thermochromic VO2 thin films on stainless steel: Experimental and theoretical studies

Thermochromic films of VO₂ were deposited by DC reactive magnetron sputtering on stainless steel substrate. Complex refractive indexes of VO₂ were determined by ellipsometric spectroscopy (0.35-16.5 μm) for different film thicknesses. Optical simulations were performed to model the spectral reflectance of the film/substrate system for a film thickness of 100 nm and 200 nm and to monitor the optical contrast of the thermochromic layers by comparing the spectral reflectance at 25 °C and 100 °C. The good agreement observed between experimental and theoretical spectra demonstrates the adequacy of the model for predicting the optical properties of the samples.