An ultra-high vacuum system for fabricating clean two-dimensional material devices
Shuaifei Guo, Mingyan Luo, Gang Shi, Ning Tian, Zhe Huang, Fangyuan Yang, Liguo Ma, Naizhou Wang, Qinzhen Shi, Kailiang Xu, Zihan Xu, Kenji Watanabe, Takashi Taniguchi, Xian Hui Chen, Dawei Shen, Liyuan Zhang, Wei Ruan, Yuanbo Zhang
Abstract
High mobility electron gases confined at material interfaces have been a venue for major discoveries in condensed matter physics. Ultra-high vacuum (UHV) technologies played a key role in creating such high-quality interfaces. The advent of two-dimensional (2D) materials brought new opportunities to explore exotic physics in flat lands. UHV technologies may once again revolutionize research in low dimensions by facilitating the construction of ultra-clean interfaces with a wide variety of 2D materials. Here, we describe the design and operation of a UHV 2D material device fabrication system, in which the entire fabrication process is performed under pressure lower than 5 × 10−10 mbar. Specifically, the UHV system enables the exfoliation of atomically clean 2D materials. Subsequent in situ assembly of van der Waals heterostructures produces high-quality interfaces that are free of contamination. We demonstrate functionalities of this system through exemplary fabrication of various 2D materials and their heterostructures.