Researchers have developed a new two-step method for growing a rare quasi-one-dimensional van der Waals material called W₆Te₆ across a 1-inch wafer, opening new possibilities for advanced nanomaterials and next-generation electronic devices.
The work was led by Yeliang Wang and Xiaolong Xu from the Beijing Institute of Technology and published in Nano Research.
Quasi-one-dimensional van der Waals materials are attracting growing interest because they can show unusual electronic, optical, and transport behavior. Their properties are highly directional, meaning they may conduct or interact with light differently along different structural directions.
However, some of the most interesting versions of these materials are metastable, meaning they are not the most energetically favored form. Because of this, they are very difficult to synthesize using conventional growth methods.
One example is W₆Te₆, a tungsten telluride material predicted to host unusual physics. Under normal tellurization conditions, tungsten tends to form the more stable WTe₂ phase instead, preventing researchers from isolating W₆Te₆.
To overcome this problem, the research team developed a kinetically controlled anion-exchange strategy. Instead of directly converting tungsten into a telluride, they first transformed a magnetron-sputtered tungsten film into a stable 2H-WS₂ template through sulfurization.
This WS₂ template has vertically aligned grains, exposing many reactive layer edges while reducing the presence of chemically inert basal planes. These exposed edges create a better pathway for controlled chemical conversion.
In the second step, the researchers introduced tellurium. Through a carefully controlled anion-exchange reaction, sulfur atoms in the WS₂ template were gradually replaced with tellurium atoms.
The key to the method is the strong W–S bonds in WS₂. These bonds create a kinetic barrier that slows the reaction, preventing the material from rapidly converting straight into the stable WTe₂ phase. This slower reaction gives researchers enough time to capture the metastable W₆Te₆ phase before the system reaches thermodynamic equilibrium.
Using atomic-resolution high-angle annular dark-field scanning transmission electron microscopy, the team directly observed the quasi-1D structure of W₆Te₆. The material consists of an inner core of six tungsten atoms surrounded by an outer sheath of six tellurium atoms. These chains are covalently bonded and stacked together through van der Waals forces.
Large-area elemental mapping confirmed that tungsten and tellurium were distributed uniformly across the material. Quantitative analysis showed a tungsten-to-tellurium ratio close to 1:1, matching the expected W₆Te₆ composition.
The researchers also mapped the growth conditions needed to control the process. Their phase diagram showed when the material remained as WS₂, when partial conversion occurred, and when phase-pure W₆Te₆ could be obtained.
Using this guide, the team successfully produced a 1-inch wafer-scale W₆Te₆ film with uniform Raman signals across the entire wafer, confirming strong macroscopic consistency.
The method is also compatible with standard photolithography. Pre-patterned tungsten structures were first converted into WS₂ and then into W₆Te₆, producing complex patterns with good uniformity and structural integrity.
This makes the approach especially promising for future device fabrication, where patternability and wafer-scale growth are essential.
Beyond W₆Te₆, the study introduces a broader strategy for creating metastable van der Waals materials that have been difficult or impossible to access through traditional methods.
The breakthrough could support future research into low-dimensional quantum materials, nanoscale electronics, anisotropic transport systems, and other advanced technologies built from wafer-scale van der Waals materials.
Journal Reference:
Xu, M., Huang, M., Ding, Y., Zhang, B., Wang, S., Fu, W., Yang, H., Zhang, Y., Ma, Y., Shao, R., Yang, S., Ye, Y., Wang, Y., & Xu, X. (2026). Kinetically-controlled synthesis of wafer-scale quasi-1D W₆Te₆. Nano Research. https://doi.org/10.26599/NR.2026.94908711