Reviewed by Lexie CornerFeb 18 2025
A recent study published in Applied Physics Express by researchers from SANKEN (The Institute of Scientific and Industrial Research) at Osaka University identified a method for preserving the electrical properties of complex materials at the nanoscale.
Raman spectra of VO2 with different thicknesses at room temperature. The right images show the corresponding optical images of VO2 grown on hBN. Image Credit: CC BY, ©2025 The Author(s). Published on behalf of The Japan Society of Applied Physics by IOP Publishing Ltd
Electronic devices capable of adapting to changes in temperature, pressure, or impact in real-time could enhance functionality and durability. Advances in quantum material miniaturization are contributing to this possibility.
A research team led by Osaka University successfully synthesized an ultrathin vanadium dioxide (VO2) film on a flexible substrate while preserving its electrical properties.
Vanadium dioxide is known for its ability to transition from an insulator to a conductor near room temperature. This property supports the development of smart and flexible electronics capable of responding to environmental changes. However, reducing the thickness of VO2 films can compromise their electrical conductivity and insulating properties.
Ordinarily, when a film is placed on a hard substrate, strong surface forces interfere with the atomic structure of the film and degrade its conductive properties.
Boyuan Yu, Study Lead Author, Osaka University
The research team synthesized VO2 films on two-dimensional hexagonal boron nitride (hBN) crystals to address thickness limitations. hBN is a stable material with weak bonding to oxides, minimizing strain on the film and preserving its structure.
The results are truly surprising. We find that by using this soft substrate, the material structure is very nearly unaffected.
Hidekazu Tanaka, Study Senior Author, Osaka University
Spectroscopy measurements confirmed that the phase transition temperature of the VO2 layers remained nearly constant at thicknesses as low as 12 nm.
This discovery significantly improves our ability to manipulate quantum materials in practical ways. We have gained a new level of control over the transition process, which means we can now tailor these materials to specific applications like sensors and flexible electronics.
Boyuan Yu, Study Lead Author, Osaka University
Quantum materials such as vanadium dioxide are integral to the design of microsensors and related devices. The research team is developing these devices and investigating methods to use thinner substrates and films for broader integration and application.
Journal Reference:
Yu, B., et al. (2025) Strain-free thin film growth of vanadium dioxide deposited on 2D atomic layered material of hexagonal boron nitride investigated by their thickness dependence of insulator–metal transition behavior. Applied Physics Express. doi.org/10.35848/1882-0786/adaf09