Control of thermochromic spectrum in vanadium dioxide by amorphous silicon suboxide layer

Vanadium dioxide ( VO 2 ) is a promising candidate for various thermochromic devices. Layering VO 2 film with amorphous silicon suboxide ( a - SiO x ) is an effective approach for controlling the thermochromic spectrum efficiently, since a - SiO x possesses an easily adjustable refractive index over a wide range. However, the crystalline quality of VO 2 is so sensitive to under- and/or over-coated materials that the a - SiO x coatings may be disadvantageous with respect to material suitability. In this study, the controllability of the thermochromic spectrum of VO 2 by employing a - SiO x layer was evaluated under several fabrication conditions and, as a result, it was found that an a - SiO x layer can control thermochromism well without any decline in the stability of VO 2 crystalline growth, which strongly suggests the possibility of expansion in the optical design for efficient thermochromic control.