Intrinsic electronic switching time in ultrathin epitaxial vanadium dioxide thin film

This letter investigates the intrinsic electronic switching time associated with the insulator-to-metal phase transition in epitaxial single crystal vanadium dioxide (VO₂) thin films using impedance spectroscopy and ac conductivity measurements. The existence of insulating and metallic phase coexistence, intrinsic to the epitaxial (001) oriented VO₂ thin film grown on a (001) rutile TiO₂ substrate, results in a finite capacitance being associated with the VO₂ films in their insulating phase that limits the electronic switching speed. Insights into the switching characteristics and their correlation to the transport mechanism in the light of phase coexistence are obtained by performing a detailed scaling study on VO₂ two-terminal devices.