Sub-3 nm Ruthenium Nanopatterns Enabled by Pattern Transfer From Supramolecular Dendrimer Templates

The fabrication of inorganic-based nanopatterns with feature sizes below 3 nm remains a fundamental challenge in nanoscience and advanced manufacturing. Existing approaches, including extreme ultraviolet lithography, block copolymer self-assembly, and colloidal nanocrystal patterning, struggle to reliably achieve such dimensions while maintaining long-range order and structural fidelity. Here, we present a pattern transfer technique from a supramolecular dendrimer templating strategy that enables highly ordered sub-3 nm ruthenium-based nanostructures over large areas (1 µm × 1 µm). The pristine dendrimer template forms a hexagonally packed cylindrical morphology with sub-5 nm periodicity, exhibiting structural stability and long-range order. Thermal annealing induces cooperative self-assembly into a single-domain array, which is selectively stained with RuO₄ to generate an inorganic RuO₂ core while preserving structural registry. This Ru-incorporated dendrimer architecture shows markedly enhanced thermal and structural stability. Electron microscopy and elemental mapping confirm vertically aligned cylindrical domains with high pattern fidelity. Subsequent calcination at 250°C removes unstained organic components without structural collapse, yielding periodic Ru-based nanostructures with a characteristic feature size of ∼2.5 nm. This work establishes a versatile bottom-up platform for ultrahigh-resolution patterning beyond current lithographic limits and provides a scalable route toward next-generation nanoelectronic, catalytic, and quantum device architectures.