Kinetically-controlled wafer-scale synthesis of quasi-one-dimensional W₆Te₆ via a WS₂ template anion-exchange strategy

Quasi-one-dimensional (quasi-1D) van der Waals (vdW) materials represent an emerging frontier in nanoscience, yet the synthesis of their metastable phases remains a significant challenge, as exemplified by W₆Te₆, whose formation is precluded by the thermodynamically favored growth of the stable WTe₂ phase. Here, we report a robust, kinetically-controlled anion-exchange (KCAE) strategy, involving a two-step process: A sputtered tungsten (W) film is converted into a stable, vertically-grained 2H-WS₂ template, followed by controlled tellurization. The high activation energy required to break the W–S bonds acts as a kinetic barrier that inhibits the formation of the WTe₂ phase, enabling the precise isolation of the metastable W₆Te₆ phase. Mechanistic studies indicate that the conversion initiates via heterogeneous nucleation at the exposed edges of the vertical WS₂ grains. This KCAE framework enables the first-ever synthesis of uniform, 1-inch wafer-scale W₆Te₆ films. Furthermore, this template-based method is fully compatible with standard photolithography, allowing for the pre-patterning of complex W₆Te₆ nanostructures. Our work establishes a generalizable platform for the wafer-scale synthesis of metastable vdW materials previously inaccessible by conventional methods.