Wang Jialong, Lu Yue, Quan Wenzhi, Hu Jingyi, Yang Pengfei, Song Ge, Fu Jiatian, Peng You, Tong Lianming, Ji Qingqing, Zhang Yanfeng
School of Materials Science and Engineering, Peking University, Beijing 100871, People's Republic of China.
School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China.
ACS Nano. 2024 Sep 12. doi: 10.1021/acsnano.4c09187.
The epitaxial growth of wafer-scale two-dimensional (2D) semiconducting transition metal dichalcogenides (STMDCs) single crystals is the key premise for their applications in next-generation electronics. Despite significant advancements, some fundamental factors affecting the epitaxy growth have not been fully uncovered, e.g., interface coupling strength, adlayer-substrate lattice matching, substrate step-edge-guiding effects, etc. Herein, we develop a model system to tackle these issues concurrently, and realize the epitaxial growth of wafer-scale monolayer tungsten disulfide (WS) single crystals on the Au(111) substrate. This epitaxial system is featured with good adlayer-substrate lattice matching, obvious step-edge-guiding effect for the unidirectionally aligned nucleation/growth, and relatively weaker interfacial interaction than that of monolayer MoS/Au(111), as evidenced by the evolution of a uniform Moiré pattern and an intrinsic band gap, according to on-site scanning tunneling microscopy/spectroscopy (STM/STS) characterizations and density functional theory calculations. Intriguingly, the unidirectionally aligned monolayer WS domains along the Au(111) steps can behave as ultrasensitive templates for surface-enhanced Raman scattering detection of organic molecules, due to the obvious charge transfer occurred at substrate step edges. This work should hereby deepen our understanding of the epitaxy mechanism of 2D STMDCs on single-crystal substrates, and propel their wafer-scale production and applications in various cutting-edge fields.
晶圆级二维（2D）半导体过渡金属二硫属化物（STMDCs）单晶的外延生长是其在下一代电子器件中应用的关键前提。尽管取得了显著进展，但一些影响外延生长的基本因素尚未完全揭示，例如界面耦合强度、吸附层 - 衬底晶格匹配、衬底台阶边缘引导效应等。在此，我们开发了一个模型系统来同时解决这些问题，并实现了在Au(111)衬底上晶圆级单层二硫化钨（WS）单晶的外延生长。根据现场扫描隧道显微镜/光谱（STM/STS）表征和密度泛函理论计算，这种外延系统具有良好的吸附层 - 衬底晶格匹配、对单向排列的成核/生长具有明显的台阶边缘引导效应，并且与单层MoS/Au(111)相比界面相互作用相对较弱，这由均匀莫尔条纹图案的演变和固有带隙所证明。有趣的是，由于在衬底台阶边缘发生明显的电荷转移，沿Au(111)台阶单向排列的单层WS域可作为用于有机分子表面增强拉曼散射检测的超灵敏模板。这项工作应加深我们对二维STMDCs在单晶衬底上外延机制的理解，并推动其在各种前沿领域的晶圆级生产和应用。
