Mitra Shuva, Avazpour Laleh, Knezevic Irena
Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Dr., Madison, WI 53706, United States of America.
J Phys Condens Matter. 2025 Feb 13;37(13). doi: 10.1088/1361-648X/adab6a.
Two-dimensional (2D) van der Waals materials are shaping the landscape of next-generation devices, offering significant technological value thanks to their unique, tunable, and layer-dependent electronic and optoelectronic properties. Time-domain spectroscopic techniques at terahertz (THz) frequencies offer noninvasive, contact-free methods for characterizing the dynamics of carriers in 2D materials. They also pave the path toward the applications of 2D materials in detection, imaging, manufacturing, and communication within the increasingly important THz frequency range. In this paper, we overview the synthesis of 2D materials and the prominent THz spectroscopy techniques: THz time-domain spectroscopy, optical-pump THz-probe technique, and optical pump-probe THz spectroscopy. Through a confluence of experimental findings, numerical simulation, and theoretical analysis, we present the current understanding of the rich ultrafast physics of technologically significant 2D materials: graphene, transition metal dichalcogenides, MXenes, perovskites, topological 2D materials, and 2D heterostructures. Finally, we offer a perspective on the role of THz characterization in guiding future research and in the quest for ideal 2D materials for new applications.
二维（2D）范德华材料正在塑造下一代器件的格局，由于其独特、可调节且依赖于层的电子和光电特性，具有重大的技术价值。太赫兹（THz）频率下的时域光谱技术为表征二维材料中载流子的动力学提供了非侵入性、非接触式方法。它们还为二维材料在日益重要的太赫兹频率范围内的检测、成像、制造和通信应用铺平了道路。在本文中，我们概述了二维材料的合成以及突出的太赫兹光谱技术：太赫兹时域光谱、光泵浦太赫兹探测技术和光泵浦-探测太赫兹光谱。通过实验结果、数值模拟和理论分析的融合，我们展示了目前对具有重要技术意义的二维材料（石墨烯、过渡金属二硫属化物、MXenes、钙钛矿、拓扑二维材料和二维异质结构）丰富的超快物理现象的理解。最后，我们对太赫兹表征在指导未来研究以及寻找适用于新应用的理想二维材料方面的作用提出了看法。
