Optical and electrical properties of thermochromic VO₂ thin films on Pt layers

VO₂ thin films have been successfully deposited on Pt(111)/Ti/SiO₂/Si substrate by means of reactive magnetron sputtering technique. The IR reflectance of the as-prepared films exhibited a big contrast (,50%) between the room temperature (258C) and high temperature (1008C) owing to the fancy semiconductor-metal transition of VO₂ thin film. Nevertheless, the initial resistance was very low and the transition cannot be triggered by the electrical field. Authors believe that the rather poor electrical switching behaviour was connected to the leakage current from the large grain boundaries and pores in the surface of the VO₂ thin film. This study may provide insights for VO₂ films grown on Pt(111)/Ti/SiO₂/Si substrates and suggest that Pt layers can serve as a suitable substrate of VO₂ films for optical switching devices but not for electrical switching ones.