The growth mechanism of VO2 multilayer thin films with high thermochromic performance prepared by RTA in air

Abstract In this paper, the multilayer thin films with SiN x /NiCr/NiCrO x /VO 2 /NiCrO x /NiCr/SiN x structure were prepared by reactive magnetron sputtering at room temperature and subsequently rapid thermal annealing (RTA) in air. The effects of annealing temperature on the microstructure and thermocheromic performance of the VO 2 multilayer thin films were systemacially investigated by UV–Vis-NIR, XRD, SEM, XPS and TEM. The results showed that the crystalline VO 2 multilayer thin films can be obtained as the temperature rose from room temperature to 301 °C within 6 s, and the high thermochromic performance with solar modulation (∆ T sol ) of 17.2%, luminous transmittance ( T lum ) of 26.9% and phase transition temperature ( T c ) of 60 °C can be acquired as the temperature rose from room temperature to 571 °C within 10 s, which indicates the VO 2 multilayer thin films show the good antioxidation. Based on growth mechanism of VO 2 multilayer thin films, it can be found that the atomic diffusion may form crystal nucleation and induce the rapid crystallization of VO 2 thin film at low temperature, the drastic diffusion reaction results in the degeneration of crystallinity and performance of VO 2 film with increasing temperature. Finally, the unbalance of interfacial stress lead to the rupture of the films, and the VO 2 was completely oxidized into V 2 O 5 . The exploration of the growth mechanism provides the basis for the optimization of the film structure and annealing parameters, so as to promote the practical application of VO 2 multilayer thin films with high thermochromic performance.