Tuning the doping ratio and phase transition temperature of VO₂ thin film by dual-target co-sputtering

A new simple way for tuning the phase transition temperature (PTT) of VO₂ thin films has been proposed to solve the problem of changing the doping ratio by using the dual-target co-sputtering method. A series of samples with W doping ratios of 0%, 0.5%, 1%, 1.5% and 2% have been fabricated by sputtering V films with the power of pure and 2% W-doped V targets from 500 W: 0W, 500W: 250W, 500W: 500W, 250W: 500Wto 0 W: 500W respectively and then annealed in an oxygen atmosphere to form VO₂. The XRD results of both pure and W-doped VO₂ samples reveal that VO₂ forms and is the main component after annealing. The PTT can be tuned by controlling the sputtering power ratio of the pure and doped targets. It can be tuned easily from 64.3 °C to 36.5 °C by using the pure and 2% W-doped targets for demonstration, with W doping ratios from 0% to 2%. It is also valid for other doping elements and is a promising approach for the large-scale production of sputtering.