Direct Synthesis of Large‐Scale WTe₂ Thin Films with Low Thermal Conductivity

Large‐scale, polycrystalline WTe 2 thin films are synthesized by atmospheric chemical vapor reaction of W metal films with Te vapor catalyzed by H 2 Te intermediates, paving a way to understanding the synthesis mechanism for low bonding energy tellurides and toward synthesis of single‐crystalline telluride nanoflakes. Through‐plane and in‐plane thermal conductivities of single‐crystal WTe 2 flakes and polycrystalline WTe 2 thin films are measured for the first time. Nanoscale grains and disorder in WTe 2 thin films suppress the in‐plane thermal conductivity of WTe 2 greatly, which is at least 7.5 times lower than that of the single‐crystalline flakes.