Hanyang team sets where crystals start
Researchers at Hanyang University in South Korea and collaborating institutions have introduced a method they call etching-flux-mediated single-centred nucleation, or EF-SCN, which directs single crystals of a two-dimensional semiconductor to begin forming in predefined central regions. Professor Woo-Hee Kim of Hanyang University and colleagues described the approach in Volume 658 of Nature on 7 October 2026.
Oxygen barrier holds back edge growth
The team grew molybdenum disulfide on patterned substrates using metal-organic chemical vapour deposition. Each designated growth region was surrounded by a hafnium oxide barrier that releases oxygen when heated to 750°C; the oxygen etches material near the pattern boundaries, suppressing nucleation there and favouring a single crystal at the centre, which then expands outwards. Substituting zirconium dioxide, which has a lower crystallisation temperature, allowed centrally nucleated triangular domains to be grown at temperatures as low as 430°C. The flow of the sulfur-supplying precursor controlled how many nuclei formed, while the molybdenum precursor flow affected how far crystals grew.
Yield above 99% across 400 sites
Crystals reached roughly 8 micrometres across, and single-crystal films filled 10-micrometre growth regions. The method gave over 99% single-crystal growth across 400 sites, and a single-crystal yield above 99% on a 2-centimetre substrate. Transistors made from the material reached field-effect mobility of up to 117 cm2 V-1s-1, and four devices integrated within one crystal showed 7.8% variation in electron mobility.
What the researchers say it is for
Kim said the approach goes past conventional area-selective growth, supporting reproducible single-crystal growth and offering a general framework for setting nucleation position, crystal geometry and later device integration, according to the release.
