Structure influenced rapid hydrogenation using metal-acid contacts on crystallographically oriented VO2 thin films

Abstract

We report on the effects of hydrogenation using metal-acid contacts with a simple method using the detachable electrode-like structure on crystallographically oriented VO2 thin films, deposited on single-crystal sapphire substrates. As the temperature increases, these films show insulator to metal transition accompanied by a structural phase transition from monoclinic to rutile phase. The said method of hydrogenation is tested around the room temperature as well as at elevated temperatures for the rutile structure. A rapid diffusion rate of hydrogen is indicated by a drastically reduced resistance of the films hydrogenated at the elevated temperatures. Moreover, when cooled down to the room temperature, the hydrogenated VO2 thin films incline to partially retain a stable rutile phase. In comparison to the hydrogenation in the monoclinic phase of VO2 film, the process of hydrogenation becomes much faster and more effective when VO2 acquires the rutile phase. © 2020