Reduced Transition Temperature in Al:ZnO/VO₂ Based Multi-Layered Device for low Powered Smart Window Application

The metal-to-insulator transition (MIT) closest to room temperature of 68-70 °C as shown by vanadium oxide (VO₂), compared with other transition metal oxides, makes it a potential candidate for smart window coating. We have successfully fabricated a potential smart window device after the optimum design of a multilayered thin film structure made out of transparent conducting oxide (aluminum doped zinc oxide) and pure VO₂ using pulsed laser deposition technique. This comprehensive study is based on two different configurations for multi-layered structure approach, with the intention to reduce the transition temperature, as well as to maintain the MIT properties that would strengthen the potential of the structure to be used for a smart window device. By creating a multi-layered structure, we were able to create a low powered device that can operate less than 15 V that leads to significant decline in the infrared transmission by a magnitude of over 40% and provided sufficient heat to trigger the MIT at a temperature around 60 °C, which is almost 10 °C lower than its bulk counterpart. This finding would positively impact the research on VO₂ thin films, not only as smart windows but also for numerous other applications like bolometers, infrared detectors, Mott transistors and many more.