Self-Assembling VO₂ Nanonet with High Switching Performance at Wafer-Scale

Abstract

Technologically controlling nanostructures is essential to tailoring the functionalities and properties of nanomaterials. Various methods free from lithography-based techniques have been employed to fabricate 2D nanostructures; however it is still hard to achieve a well interconnected 2D regular nanostructure. Here, we demonstrate a facile chemical solution method to self-assemble a regular and interconnected VO2 nanonet on the wafer scale. The nanonet shows a well-defined 2D truss network constructed by VO2 nanorods with twinning relationships. The growth direction and crystallographic orientation of nanorods are synchronously controlled, leading to horizontally epitaxial growth of nanorods along three symmetric directions of the (001) single-crystal sapphire substrate. The unique nanonets enable the acquisition of excellent resistance switching properties and dramatic fatigue endurance. A large resistance change of near 5 orders with a 1.7 °C width of the hysteresis loop is characterized comparably to the properties of single crystals without detectable degradation after 500 cycles over the metal-to-insulator transition. It indicates that the nanonet can serve as an exceptional candidate for practical application in switching functional devices. Our findings offer a novel pathway for self-assembly of 2D ordered nanostructures, which would provide new opportunities for the bottom-up integration of nanodevices.

Hydrothermal Synthesis of VO2 Polymorphs: Advantages, Challenges and Prospects for the Application of Energy Efficient Smart Windows

“…By the same method, the phase and thickness of VO 2 film can be controlled simply via changing precursor concentration and reaction time . Without the TiO 2 buffer layer, VO 2 nanonet with high switching performance was obtained on sapphire substrate after a short annealing at 400 °C for 30 s in low vacuum condition …”

Hydrothermal growth of VO2 nanoplate thermochromic films on glass with high visible transmittance

“…The substrates with polarity and crystal orientations were usually used to grow fine organized thin films 26 27 28 . Our recent work has demonstrated that high quality epitaxial VO 2 thin films can be grown on sapphire substrates by hydrothermal method 29 . Compared to the costly single crystal substrate, the buffer layer prepared on glass is an economic way to grow fine films.…”

Vanadium Dioxide: The Multistimuli Responsive Material and Its Applications

“…Meanwhile, the thermomechanical devices like resonator and actuator are based on the crystal contraction along the c ‐axis (≈1%) and expansion on the a ‐axis direction (≈0.6%) when MIT happens . Moreover, as the conductivity of VO 2 changes up to five magnitudes upon the MIT due to the overlapping and separation of energy band in the crystal, the fabrication of temperature sensor and other thermal activated electrical device becomes possible.…”