Electro-thermal control of aluminum-doped zinc oxide/vanadium dioxide multilayered thin films for smart-device applications

Abstract

We demonstrate the electro-thermal control of aluminum-doped zinc oxide (Al:ZnO) /vanadium dioxide (VO ₂) multilayered thin films, where the application of a small electric field enables precise control of the applied heat to the VO ₂ thin film to induce its semiconductor-metal transition (SMT). The transparent conducting oxide nature of the top Al:ZnO film can be tuned to facilitate the fine control of the SMT of the VO ₂ thin film and its associated properties. In addition, the Al:ZnO film provides a capping layer to the VO ₂ thin film, which inhibits oxidation to a more energetically favorable and stable V ₂O ₅ phase. It also decreases the SMT of the VO ₂ thin film by approximately 5–10 °C because of an additional stress induced on the VO ₂ thin film and/or an alteration of the oxygen vacancy concentration in the VO ₂ thin film. These results have significant impacts on technological applications for both passive and active devices by exploiting this near-room-temperature SMT.