Ultra-high phase transition amplitude of Fe-doped high-performance VO2 films manufactured by DC-magnetron sputtering for modulation application

In the field of electronic modulation, vanadium dioxide (VO₂) is a potential material owing to its function of automatic insulator-to-metal transition (MIT) which can induce rapid changes in electrical resistivity through MIT. Nevertheless, the application of modulator based on VO₂ is limited by some performance shortcomings, including wide hysteresis loop width (ΔH), high phase transition temperature (T_c) as well as low phase transition amplitude (A_MIT). In this work, by DC (DirectCurrent)-magnetron sputtering with doping Fe³⁺ into VO₂ films, narrowed ΔH and decreased Tc are observed. Interestingly, the Fe doped VO₂ films show ultra-high phase transition amplitude despite the low T_c due to the influence of Fe dopants. Specifically, the 0.5% Fe-doped VO₂ film shows the best MIT characteristics with ultra-high phase transition amplitude of 10⁴, narrow ΔH decreased to 9.8° and low T_c around 60.02°C, which is considered to be the first time to highly heighten the electrical MIT properties by Fe doping. In addition, we also comprehensively studied the influences of doping with Fe element on the MIT properties and microstructures based on characterization such as SEM, XRD, Raman shift and XPS results. These results show that our unique preparation method can manufacture VO₂ thin films with excellent MIT properties, which will be beneficial to the popularization and publicity of VO₂ based electrical modulator.