Hydrogen-doping Stabilized Metallic VO2 (R) Thin Films and their Application to Suppress Fabry-Perot Resonances in the Terahertz Regime

Abstract

We demonstrate that catalyst-assisted hydrogen spillover doping of VO₂ thin films significantly alters the metal-insulator transition characteristics and stabilizes the metallic rutile phase at room temperature. With hydrogen inserted into the VO₂ lattice, high resolution X-ray diffraction reveals expansion of the V-V chain separation when compared to the VO₂(R) phase. The donated free electrons, possibly from O-H bond formation, stabilize the VO₂(R) to low temperatures. By controlling the amount of dopants to obtain mixed insulating and metallic phases, VO₂ resistivity can be continuously tuned until a critical condition is achieved that suppresses Fabry-Perot resonances. Our results demonstrate that hydrogen spillover is an effective technique to tune the electrical and optical properties of VO₂ thin films.