Sun Shuwen, Jarillo-Herrero Pablo
Department of Physics, Massachusetts Institute of Technology.
Department of Physics, Massachusetts Institute of Technology;
J Vis Exp. 2025 Jul 11(221). doi: 10.3791/68230.
Moiré superlattices constitute a versatile platform to investigate emergent phenomena arising from the interplay of strong correlations and topology, while offering flexible in situ tunability. However, the fabrication of such moiré superlattices is challenging. It is difficult to achieve highly uniform devices with a precise twist angle because of the unintentional introduction of heterostrain, twist angle disorder, and angle/lattice relaxation during the nanofabrication process. This article introduces an optimized, experience-informed protocol for fabricating high-quality graphene-based moiré superlattice devices, focusing on a modified dry transfer technique. The transfer process is performed in a highly tunable, custom-built transfer setup that enables precise position, angle, and temperature control. By combining rigorous flake selection criteria, pre-cleaned bubble-free bottom gates, and graphene laser ablation, the moiré superlattice is constructed by deliberately overlaying twisted graphene flakes at a submicron speed at room temperature. Through precise control of the transfer process, the resulting graphene moiré superlattice devices exhibit high uniformity and desired twist angles. This optimized protocol addresses existing challenges in the fabrication of graphene-based moiré superlattice devices and paves the way for further advances in the rapidly evolving field of moiré materials.
莫尔超晶格构成了一个通用平台，用于研究由强关联和拓扑相互作用产生的新兴现象，同时提供灵活的原位可调性。然而，制造这种莫尔超晶格具有挑战性。由于在纳米制造过程中无意引入了异质应变、扭转角无序以及角度/晶格弛豫，很难实现具有精确扭转角的高度均匀的器件。本文介绍了一种优化的、基于经验的协议，用于制造高质量的基于石墨烯的莫尔超晶格器件，重点是一种改进的干法转移技术。转移过程在一个高度可调的定制转移装置中进行，该装置能够实现精确的位置、角度和温度控制。通过结合严格的薄片选择标准、预清洁的无气泡底部栅极和石墨烯激光烧蚀，在室温下以亚微米速度故意叠加扭曲的石墨烯薄片来构建莫尔超晶格。通过精确控制转移过程，所得的石墨烯莫尔超晶格器件表现出高均匀性和所需的扭转角。这种优化的协议解决了基于石墨烯的莫尔超晶格器件制造中现有的挑战，并为莫尔材料快速发展的领域中的进一步进展铺平了道路。
