  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.
