Reduction of Epitaxial MoO₂ to Mo by High-temperature Hydrogen Annealing

The molybdenum oxide (MoO₂) reduction process using hydrogen gas at elevated temperatures is commonly used to purify Mo metal. We report a methodology to reduce epitaxial MoO₂ films using diluted hydrogen gas comprising 3% hydrogen and 97% argon. Under the reaction temperature that is similar to the reduction process of bulk MoO₂, it is remarkable that oxygen-free epitaxial Mo metal films are created according to structural characterizations and spectroscopic studies. The result of this study helps in understanding the reduction process of epitaxial binary oxides.