Interface‐Driven Control of Vanadium Carbide Micro‐ and Nanocrystal Growth During Chemical Vapor Deposition

ABSTRACT Transition metal carbides are important functional materials because of their high electrical conductivity, thermal stability, mechanical robustness, and potential in catalysis, energy storage, and electronics. Interface engineering is essential for controlling their growth during chemical vapor deposition, yet vanadium‐based systems remain insufficiently explored. Here, an interface‐driven strategy is demonstrated for growing vanadium carbide micro‐ and nanocrystals using a fully wrapped Cu/V foil configuration that stabilizes vanadium surfaces and suppresses competing reactions at high temperature. Growth at 1083°C, just below the melting point of copper (∼1085°C), creates a stable, reproducible interfacial environment without additional metal supports. Varying carbon supply and growth time reveals two distinct growth regimes. A higher methane flow rate favors continued nucleation, resulting in increased crystal density with limited lateral expansion, whereas a lower methane flow rate favors lateral crystal growth and domain merging, resulting in larger crystal domains. Increasing the growth time results in higher surface coverage at both CH 4 flow rates and may influence the amount of vanadium reaching the exposed Cu surface. Beyond vanadium carbide, this concept provides a broadly applicable framework for diffusion‐mediated synthesis, enabling control over morphology and surface coverage in transition metal carbides and related low‐dimensional materials.