Highly transparent VO2-SiO2 films with excellent infrared characteristics by dual-target magnetron sputtering

With the aim to fabricate high quality and boosting the optical performance of vanadium dioxide (VO 2 ) film, basing on effective medium theory, dual-target magnetron sputtering method is first introduced into VO 2 -SiO 2 composite film on quartz by changing the flow ratio of Argon and oxygen. X-Ray diffraction measurement indicates the purity of the composite film. Atomic force microscopy measurement shows that the minimum grain size is about 45nm. Infrared (IR) switching characteristic is well demonstrated by a double-frequented He-Ne laser at the wavelength of 3mμ,compare to VO 2 film obtained at the same sputtering time, the result reveals that the composite film exhibit excellent IR switching property, furthermore, multi-wavelength tests and calculations show that all of the obtained composite films exhibit high integrate luminous transmittance of 50%, and the transmittance in semiconducting phase of one thin film is 65% and decreases to 24% in metallic phase at the wavelength of 2mμ , with the switching efficiency of 63%. High visible transmittance and excellent infrared switching characteristics make the film an appropriate candidate for laser protection as well as smart windows.