Van der Waals epitaxy suppresses thermal rupture in ultrathin metals

Metal films are indispensable to modern electronics, yet their continued downscaling is fundamentally limited by thermodynamic instability. In particular, ultrathin metals can exhibit liquid-like Plateau–Rayleigh instability and rupture at temperatures far below their bulk melting point, creating a long-standing challenge for both integrated circuits and emerging 2D-material devices. Here we show that the liquid-like instabilities of thin metals can be suppressed at the microstructural origin by using graphene as a van der Waals (vdW) template. The vdW template induces a highly uniform texture and reorganizes grain boundaries into a low-energy network, thereby shifting capillary driving forces from rupture-promoting to self-healing. Remarkably, while conventional 20-nm-thick gold films break up into islands below 300 °C, templated films not only remain continuous above 600 °C but also evolve into atomically flat structures. We show that this exceptional stability greatly broadens the processing window for nanoscale interconnects and electrodes, and enables high-quality integration of metals with 2D materials. Ultrathin metal films are necessary for future electronics, but their thickness downscaling is normally limited by thermodynamic instability. Here the authors demonstrate the van der Waals epitaxy of 20-nm thick metallic films on graphene templates with improved thermal stability and structural/electrical properties.