Wafer-size VO2 film prepared by water-vapor oxidant

TL;DR

This paper presents a water-vapor oxidation method for producing high-quality, wafer-scale VO2 films with uniform surface and sharp phase transition, broadening the oxidation parameter window and simplifying the process.

Contribution

The study introduces a water-vapor oxidation technique that enables large-scale, uniform VO2 film growth with an expanded temperature window and improved film quality.

Findings

Water-vapor oxidation broadens the VO2 growth temperature window.

The resulting VO2 films are uniform with sharp resistance changes.

Water-vapor acts as an effective, modest oxidant for large-scale VO2 film fabrication.

Abstract

The growth of wafer-scale and uniform monoclinic VO2 film was a challenge if considering the multivalent vanadium atom and the various phase structures of VO2 compound. Directly oxidizing metallic vanadium film in oxygen gas seemed to be an easy way, while the oxidation parameters were extremely sensitive due to the critical preparation window. Here we proposed a facile thermal oxidation by water-vapor to produce wafer-scale VO2 films with high quality. Results indicated that by using the water-vapor oxidant, the temperature window for VO2 growth was greatly broadened. In addition, the obtained wafer-size VO2 film showed very uniform surface and sharp resistance change. The chemical reaction routes with water-vapor were calculated, which favored the VO2 film growth. Our results not only demonstrated that the water-vapor could be used as a modest oxidizing agent, but also showed the unique advantage for large size VO2 film preparation.