Low-temperature wafer-scale fabrication of vertical VO2 nanowire arrays

Single-crystalline vanadium dioxide nanowires (VO2 NWs) have attracted significant interest due to their unique characteristics, which originate from the single-domain metal-insulator phase transition (MIT) property. However, the lack of facile technologies to produce vertical nanowire arrays (NAs) in a large area has limited the mass fabrication of VO2-based devices. Here, an antimony-assisted hydrothermal method is developed for the low-temperature production of wafer-scale vertical VO2 NAs on arbitrary substrates of glass, quartz, and silicon. Sb2O3 plays a key role in the controlled growth of pure VO2 (M1) by modulating the size, density, alignment, and MIT properties of VO2 NAs. Furthermore, the growth mechanism of vertical VO2 NAs is explained. In contrast to conventional fabrication technologies, the weak interaction between NA films and substrates enables a much easier transfer of VO2 NAs for various potential applications.