Role of seed layer in van der Waals growth of vanadium dioxide film on mica prepared by chemical solution deposition

Vanadium dioxide (VO2) has unique electrical and optical properties, which have practical applications in many devices. However, preparing high-quality VO2 films and transferring them to flexible substrates by an economic and simple way are still challenging. Functional thin films can be grown on van der Waals (vdW) substrates and then transferred to flexible substrates due to the weak interaction between films and their substrates. Herein, VO2 thin films were grown on mica substrates by using the polymer-assisted deposition technique. By controlling the ion concentration in the polymer precursor solution, a flat seed layer was prepared at the initial growth stage. It was found that the introduction of the seed layer can improve the crystallinity, increase the grain size and reduce the defects of the VO2 thin films. It is believed that less nucleation density and layered growth at the initial growth stage are critical to the formation of large size grains. Our results confirmed that chemical solution deposition can prepared high-quality VO2 films on vdW substrates.