In semiconductor manufacturing, nucleation, when crystals first begin to form, determines where and how they grow. This is particularly important for two-dimensional (2D) semiconductors, which are promising for next-generation electronics. However, conventional area-selective growth methods cannot reliably control where crystals begin forming within designated regions, making it difficult to produce large single crystals and precisely aligned structures for electronic devices.
In a study published in Volume 658 of Nature on October 7, 2026, Professor Woo-Hee Kim from Hanyang University, Republic of Korea, and colleagues introduced a method called etching-flux-mediated single-centred nucleation (EF-SCN), which uses oxygen released from an oxide barrier to control where crystals begin to form.
Using this approach, the researchers grew molybdenum disulfide (MoS2), a two-dimensional semiconductor, on patterned substrates using metal-organic chemical vapor deposition. They surrounded each designated growth region with a hafnium oxide (HfO2) barrier that releases oxygen when heated to 750°C. The oxygen etches the material near the pattern boundaries, suppressing nucleation in these areas and favoring the formation of a single crystal at the center. As growth continues, the crystal expands outwards to form a larger single-crystal region.
The researchers demonstrated consistent, centrally located nucleation across patterned arrays. As the crystals grew, they filled their designated regions, forming single-crystal domains several micrometers across.
The researchers also modified the method to allow crystal growth at lower temperatures by replacing HfO2 with zirconium dioxide, which has a lower crystallization temperature and serves as an alternative etching-flux barrier. This allowed them to grow uniform, centrally nucleated triangular single-crystal MoS₂ domains at temperatures as low as 430°C.
The researchers further investigated how growth conditions affect crystal formation. They found that the flow rate of diethyl sulfide, which supplies sulfur, primarily controls the number of nuclei that form. Too little can prevent nucleation, while too much can produce multiple crystals. The molybdenum precursor flow rate affects how far the crystals grow. By adjusting these conditions and the pattern dimensions, the researchers produced large crystals and line-shaped channels suitable for transistor integration.
The researchers produced crystals approximately 8 micrometers across and single-crystal films filling 10-micrometre growth regions. Across a 2-centimetre substrate, the method achieved a single-crystal yield exceeding 99%.
“To assess the electronic properties of these crystals, our team fabricated field-effect transistors using the MoS2 grown via our EF-SCN method,” says Prof. Kim. The devices achieved a field-effect mobility of up to 117 cm2 V-1s-1. They integrated four transistors within a single crystal, with just 7.8% variation in electron mobility, demonstrating the potential to build denser electronic circuits with more consistent performance.
These findings establish EF-SCN as a method for controlling where crystals form, how they grow, and how they can be incorporated into electronic devices.
“This approach goes beyond conventional area-selective growth and enables highly reproducible single-crystal growth and provides a general framework for programming nucleation position, crystal geometry and subsequent device integration,” says Prof. Kim.
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Reference
DOI: 10.1038/s41586-026-11095-1
About Hanyang University ERICA
Hanyang University ERICA (Education Research Industry Cluster at Ansan) is a prominent research-focused campus established in 1979 in Ansan, South Korea. ERICA offers undergraduate and graduate programs. ERICA is renowned for its active industry-university cooperation, offering students hands-on experience through partnerships with various industries. This ensures that graduates are well-prepared to meet societal needs and excel in their respective fields. With state-of-the-art facilities and a supportive learning environment, Hanyang University ERICA empowers students to pursue their passions and contribute meaningfully to society, staying true to the university's founding philosophy of "Love in Deed and Truth."
Website: https://www.hanyang.ac.kr/web/eng/erica-campus1
About the Author
Woo-Hee Kim is a professor at Hanyang University ERICA specializing in atomic-scale deposition, surface engineering, and patterning technologies for next-generation semiconductor devices. His research encompasses atomic layer deposition (ALD), chemical vapor deposition, molecular layer deposition, area-selective ALD, and atomic layer etching, with applications in metal and metal-oxide thin films, two-dimensional chalcogenide semiconductors, and inorganic photoresists for extreme ultraviolet patterning. He previously worked at Samsung Electronics and Micron Technology and conducted postdoctoral research at Stanford University.
Nature
Experimental study
Not applicable
Spatially deterministic nucleation of 2D semiconductors by etching flux
7-Oct-2026
Kibum Kang is a co-founder, chief executive officer and equity holder of TDS Innovation Inc., a company engaged in the development of two-dimensional semiconductor materials, processes and equipment. Byungjo Kim and Woo-Hee Kim are unpaid members of the board of directors of TDS Innovation Inc. Jeongwon Park, Seohyun Jeong, Chan Lim, Junhyeok Kim and Chang-Soo Lee are employees of TDS Innovation Inc. The other authors declare no competing interests.