This method can guide the growth of single crystals to begin in a predefined central region.
Gyeonggi Province, South Korea, November 6, 2026 / PRNewswire / -- In two-dimensional semiconductor manufacturing, controlling the initial formation location of crystals has always been a challenge. Researchers from Hanyang University and collaborating institutions have developed a method called "etching flux-mediated single-center nucleation" ( etching-flux-mediated single-centred nucleation EF-SCN ), which can guide crystal formation to specific locations, achieving over 99% single-crystal growth at 400 positions.
In semiconductor manufacturing, nucleation is the process by which crystals begin to form for the first time; it determines where and how the crystals will grow. This is particularly important for two-dimensional (2D) semiconductors that are expected to be used in next-generation electronic devices. However, traditional regional selective growth methods cannot reliably control the initial formation locations of crystals within designated areas, making it difficult to produce large-sized single crystals and precise aligned structures for electronic devices.
In a study published on October 7, 2026, in Volume 658 of Nature, Professor Woo - Hee Kim from Hanyang University in South Korea and his colleagues introduced a method EF-SCN. This method utilizes oxygen released by an oxide barrier layer to control the location where crystal formation begins.
Using this method, researchers grew two-dimensional semiconductor molybdenum disulfide (MoS₂) on patterned substrates through metal-organic chemical vapor deposition. They established a hafnium oxide (HfO₂) barrier layer around each designated growth area; this barrier layer releases oxygen when heated to 750 degrees Celsius. The oxygen etches the material near the pattern boundaries, inhibiting nucleation in those areas and promoting the formation of single crystals in the central regions. As growth continues, the crystals expand outward, forming larger single-crystal regions.
Researchers demonstrated a stable, centric nucleation phenomenon within pattern arrays. As the crystals grew, they filled their designated areas, forming single-crystal domains with lateral dimensions of several micrometers.
Researchers also made improvements to this method by replacing HfO 2 with zirconia, enabling crystal growth at lower temperatures. Zirconia has a lower crystallization temperature and can be used as an alternative etching flux barrier layer. This allowed them to grow uniform, centrally nucleated triangular single-crystal MoS 2 domains at temperatures as low as 430 degrees Celsius.
Researchers further investigated how growth conditions affect crystal formation. They found that the flow rate of diethyl sulfide, which serves as the sulfur source, primarily controls the number of crystal nuclei formed. Too low a flow rate may result in the inability to form nuclei, while too high a flow rate could lead to the formation of multiple crystals. The flow rate of the molybdenum precursor, on the other hand, affects the growth distance of the crystals. By adjusting these conditions as well as the pattern size, the researchers were able to produce large-sized crystals and linear channels suitable for transistor integration.
The researchers prepared crystals with a lateral dimension of approximately 8 micrometers and obtained single-crystal thin films that filled a growth region of 10 micrometers. On a 2-centimeter substrate, this method achieved a single-crystal yield of over 99%.
Professor Kim stated, "In order to evaluate the electronic properties of these crystals, our team prepared field-effect transistors using MoS 2 grown by the EF-SCN method." These devices achieved a field-effect mobility of up to 117 cm 2 V⁻¹ s⁻¹. The research team integrated 4 transistors within a single crystal, with a difference in electron mobility of only 7.8%, demonstrating the potential for constructing higher-density, more consistently performing electronic circuits.
These findings establish EF-SCN as a method for controlling the formation location of crystals, how crystals grow, and how to integrate them into electronic devices.
Professor Kim stated: "This method breaks through the limitations of traditional regional selective growth, enabling highly reproducible single crystal growth and providing a general framework for programmable control of nucleation sites, crystal geometric shapes, and subsequent device integration."
Reference information
Regarding Hanyang University ERICA Campus, website: https:// www.hanyang.ac.kr / web / eng / erica-campus1
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