SAINT

12/11(목) 전문가초청특강은 성신여자대학교 한혁진 교수님을 모시고 진행합니다.

관심있는 분들의 많은 참석 부탁드립니다.

ㅁ주제: Towards Energy-Efficient Materials: From Topological Metal Nanowires to Single-Crystal Synthesis

ㅁ일시: 12/11 (목) 16:00

ㅁ장소: 제2종합연구동 83188호

ㅁ약력: 

ㅁ초록: 

Information and communication technology is projected to account for more than 20percent of global electricity usage by 2030, underscoring the need for energy efficient computing systems. A central bottleneck lies in on chip interconnects, where copper suffers from severe resistivity increases as dimensions shrink. Topological semimetals offer an alternative due to high conductivity, high mobility, and topologically protected surface states that suppress electron scattering at the nanoscale. Molybdenum phosphide (MoP), a triple point topological semimetal with excellent transport properties, exemplifies this potential. Our studies on MoP nanowires synthesized by reacting oxide nanostructures with phosphorus precursors show that their resistivity scaling surpasses Cu (with TaN liner) and Ru, with line resistance becoming comparable to, or superior to, state-of-the-art interconnect metals.

As this research progressed, it became clear that understanding intrinsic transport in topological metals requires controlled access to high-quality single crystals, including metastable phases inaccessible through conventional synthesis. To address this challenge, we developed a liquid metal-assisted CVD strategy using liquid gallium as a growth medium. The high surface energy and enhanced atomic mobility in liquid Ga promote Mo diffusion and controlled reaction with phosphorus vapor, enabling phase-pure single crystals of both stable MoP and metastable Mo₄P₃.

By tuning synthesis conditions, distinct facet-defined MoP morphologies—nanoplates enriched with (0001) facets and pillar structures dominated by (10-10) facets—were obtained. Electrochemical measurements show that MoP pillars achieve over 92percent selectivity in the two-electron oxygen reduction reaction to H₂O₂, with sustained Faradaic efficiency above 90percent. Density functional theory calculations reveal that facet-dependent OOH adsorption governs this enhanced performance. The successful synthesis of metastable Mo₄P₃ further demonstrates that the liquid metal-assisted method provides a general platform for stabilizing quasi-stable TMP phases and enabling detailed structure–property studies previously out of reach.

Together, these research directions establish a unified framework linking topological metal nanowires for low-resistance interconnects with a liquid metal-enabled platform for discovering and stabilizing new TMP phases. This integrated approach supports the development of energy-efficient interconnect technologies while opening broader opportunities in catalysis, sustainable chemical production, and metastable material design.