Dr. Yi Wan received her B.Eng. degree in Materials Science and Engineering from the Southern University of Science and Technology and her Ph.D. in Materials Science and Engineering from King Abdullah University of Science and Technology. She subsequently served as a Research Assistant Professor in the Department of Mechanical Engineering at the University of Hong Kong, where her research focuses on elucidating the vapor-phase growth kinetics and thermodynamics that govern crystallization pathways, domain formation, defect generation, and interface properties in 2D materials. In January 2025, she joined the Department of Materials Science and Engineering at National University of Singapore as an Assistant Professor. Her research interests focus on the synthesis and integration of novel low-dimensional semiconductor materials for next-generation electronics and optoelectronics.

Transition metal dichalcogenides (TMDs) such as MoS2 and WSe2 are foundational to the future of 2-dimensional electronics, offering scalable alternatives to silicon for sub-5 nm nodes. However, transitioning from lab-scale flakes to wafer-scale single crystals while maintaining low defect densities remains a significant challenge. This talk is divided into two primary thrusts: the controlled growth of large-area single crystals and the implementation of advanced defect-suppression techniques. First, we discuss the epitaxial growth mechanisms of monolayer MoS2 and WSe2 on sapphire substrates, focusing on grain alignment and the prevention of twin boundaries to achieve continuous single-crystalline films [1-4]. Second, we introduce chemical strategies to minimize intrinsic defects, specifically chalcogen vacancies, during the growth process [5]. We highlight a moisture-assisted transport reaction that utilizes volatile tungsten hydroxide species to lower reaction barriers, alongside other chemical vapor deposition (CVD) optimizations. By combining large-scale growth with atomic-scale defect control, this work paves the way for high-performance p-type and n-type 2D logic devices and optoelectronic.

1. Y. Wan* et al. Nature Nanotechnology, 2023, 1748-3395.
2. Y. Wan* et al. Advanced Materials, 2024, 2404923.
3. Y. Wan* et al. Advanced Functional Materials, 2023, 2311387
4. Y. Wan* et al. ACS Nano, 2026, 20 (2), 2104-2113
5. Y. Wan et al. Nature Communications, 2022, 13, 4149.