Vanadium Dioxide Thin Films Synthesized Using Low Thermal Budget Atmospheric Oxidation

TL;DR

This paper presents a rapid atmospheric oxidation method to synthesize high-quality VO2 thin films with significant resistance and optical reflectance switching, reducing oxidation time by over tenfold compared to previous methods.

Contribution

The authors introduce a modified atmospheric oxidation process that significantly shortens VO2 film synthesis time while maintaining desirable phase transition and optical properties.

Findings

VO2 films exhibit ~3 orders of magnitude resistance change.

Optical reflectance switching observed in long-wave infrared.

Reduced oxidation duration by over an order of magnitude.

Abstract

Vanadium dioxide is a complex oxide material, which shows large resistivity and optical reflectance change while transitioning from the insulator to metal phase at ~68 {\deg}C. In this work, we use a modified atmospheric thermal oxidation method to oxidize RF-sputtered Vanadium films. Structural, surface-morphology and phase-transition properties of the oxidized films as a function of oxidation duration are presented. Phase-pure VO2 films are obtained by oxidizing ~130 nm Vanadium films in short oxidation duration of ~30 seconds. Compared to previous reports on VO2 synthesis using atmospheric oxidation of Vanadium films of similar thickness, we obtain a reduction in oxidation duration by more than one order. Synthesized VO2 thin film shows resistance switching of ~3 orders of magnitude. We demonstrate optical reflectance switching in long-wave infrared wavelengths in VO2 films synthesized using atmospheric oxidation of Vanadium. The extracted refractive index of VO2 in the insulating and in the metallic phase is in good agreement with VO2 synthesized using other methods. The considerable reduction in oxidation time of VO2 synthesis while retaining good resistance and optical switching properties will help in integration of VO2 in limited thermal budget processes, enabling further applications of this phase-transition material.