High Infrared Reflectance Modulation in VO2 Films Synthesized on Glass and ITO coated Glass substrates using Atmospheric Oxidation of Vanadium

TL;DR

This study demonstrates high infrared reflectance modulation in VO2 films synthesized via atmospheric oxidation on glass and ITO substrates, showing potential for optical applications with a simple, low-cost process.

Contribution

It introduces a low thermal budget atmospheric oxidation method to synthesize VO2 films with high infrared reflectance switching on common substrates.

Findings

Peak reflectance switching of ~76% on glass

Peak reflectance switching of ~79% on ITO coated glass

Refractive index data aligns with other synthesis methods

Abstract

Vanadium Dioxide (VO2) is a strongly correlated material, which exhibits insulator to metal transition at ~68 C along with large resistivity and infrared optical reflectance modulation. In this work, we use atmospheric pressure thermal oxidation of Vanadium to synthesize VO2 films on glass and ITO coated glass substrates. With the optimized short oxidation durations of 2 min and 4 min, the synthesized VO2 film shows high optical reflectance switching in long-wavelength infrared on glass substrates and mid-wavelength infrared on ITO coated glass substrates, respectively. Peak reflectance switching values of ~76% and ~79% are obtained on the respective substrates, which are among the highest reported values. Using the reflectance data, we extract VO2 complex refractive index in infrared wavelengths, in both the insulating and metallic phases. The extracted refractive index shows good agreement with VO2 synthesized using other methods. This demonstration of high optical reflectance switching in VO2 thin films, grown on low cost glass and ITO coated glass substrates, using a simple low thermal budget process will aid in enhancing VO2 applications in the optical domain.