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.
Xu et al. (Wed,) studied this question.