High-density growth of single-crystal CoSi nanowires via plasma-driven synergistic surface engineering

초록

Cobalt monosilicide (CoSi), a chiral topological semimetal, is a promising candidate for next-generation nanoscale interconnects, but the synthesis of high-quality nanowires is hindered by low nucleation density and poor uniformity. Here, we demonstrate a substrate-engineering strategy using a mixed Ar/SF6 plasma pretreatment on Si substrates that enables the growth of dense, uniform, single-crystal CoSi nanowires. This mixed plasma synergistically creates a dual-scale surface morphology with controlled nanoscale roughness and low oxygen content, providing a high density of uniformly distributed nucleation sites. Consequently, the engineered surfaces yield a high nanowire density of similar to 22.6 wires/mu m(2), over two orders of magnitude greater than on untreated Si. The resulting nanowires are phase-pure, single-crystalline B20 CoSi with a preferential [2 1 1] growth direction. This work establishes a balanced physical-chemical plasma modification route that is broadly applicable to other metal silicide and topological nanowire systems, providing a scalable pathway for integrating chiral topological materials into advanced electronic and interconnect technologies.

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