Yang Kyungmin, Lee Yuna, Rhee Dongjoon, Choi Bongjun, Alfieri Adam, Drndić Marija, Jariwala Deep, Lee Gwan-Hyoung
Department of Materials Science and Engineering, Seoul National University, Seoul, 18826, South Korea.
Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Adv Sci (Weinh). 2025 Aug 11:e06488. doi: 10.1002/advs.202506488.
Transition metal dichalcogenides (TMDs) are promising materials for next-generation electronics due to their atomically thin body and exceptional optoelectronic properties. Their ultrathin and stiff nature make them highly sensitive to strain, enabling modulation of lattice and band structures and enhancing carrier mobility via tensile strain. While uniform strain degrades optical properties of MoS due to the indirect bandgap, localized strain enhances them through the funnel effect, highlighting the importance of localized strain engineering. In this study, localized strain is achieved in monolayer MoS using geometrically confined quasi-van der Waals (qvdW) recrystallization of patterned gold nanopillars. After transferring hBN-encapsulated MoS onto the pillars and annealing, the gold recrystallizes into thicker, more crystalline structures, inducing ≈0.15% local tensile strain. This results in a 65-fold increase in photoluminescence (PL) intensity due to the funnel effect, Fabry-Pérot interference, and Purcell effect. Additionally, field-effect mobility is significantly enhanced to 100 cmVs, a two-order of magnitude improvement. The work shows a way to apply local strain in MoS using geometrically confined gold pillars via qvdW recrystallization, offering a possibility for advanced optoelectronic devices.
过渡金属二硫属化物（TMDs）因其原子级薄的结构和优异的光电特性，是下一代电子器件的理想材料。它们超薄且坚硬的特性使其对应变高度敏感，能够通过拉伸应变调节晶格和能带结构并提高载流子迁移率。虽然均匀应变由于间接带隙会降低MoS的光学性能，但局部应变通过漏斗效应增强其光学性能，凸显了局部应变工程的重要性。在本研究中，通过图案化金纳米柱的几何受限准范德华（qvdW）再结晶，在单层MoS中实现了局部应变。将hBN封装的MoS转移到柱子上并退火后，金再结晶形成更厚、结晶度更高的结构，诱导出约0.15%的局部拉伸应变。由于漏斗效应、法布里 - 珀罗干涉和珀塞尔效应，这导致光致发光（PL）强度增加了65倍。此外，场效应迁移率显著提高到100 cm²V⁻¹s⁻¹，提高了两个数量级。这项工作展示了一种通过qvdW再结晶利用几何受限金柱在MoS中施加局部应变的方法，为先进光电器件提供了可能性。
