Dry pick-and-flip assembly of van der Waals heterostructures for microfocus angle-resolved photoemission spectroscopy

Satoru Masubuchi; Masato Sakano; Yuma Tanaka; Yusai Wakafuji; Takato Yamamoto; Shota Okazaki; Kenji Watanabe; Takashi Taniguchi; Jincai Li; Hirotaka Ejima; Takao Sasagawa; Kyoko Ishizaka; Tomoki Machida

doi:10.1038/s41598-022-14845-z

Dry pick-and-flip assembly of van der Waals heterostructures for microfocus angle-resolved photoemission spectroscopy

Sci Rep. 2022 Jun 29;12(1):10936. doi: 10.1038/s41598-022-14845-z.

Authors

Satoru Masubuchi^#¹, Masato Sakano^#², Yuma Tanaka^#², Yusai Wakafuji³, Takato Yamamoto², Shota Okazaki⁴, Kenji Watanabe⁵, Takashi Taniguchi^{3

6}, Jincai Li⁷, Hirotaka Ejima⁷, Takao Sasagawa⁴, Kyoko Ishizaka^{2

8}, Tomoki Machida⁹

Affiliations

¹ Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan. msatoru@iis.u-tokyo.ac.jp.
² Quantum-Phase Electronics Center and Department of Applied Physics, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan.
³ Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
⁴ Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Kanagawa, 226-8503, Japan.
⁵ Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
⁶ International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan.
⁷ Department of Materials Engineering, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8656, Japan.
⁸ RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama, 351-0198, Japan.
⁹ Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan. tmachida@iis.u-tokyo.ac.jp.

^# Contributed equally.

Abstract

We present a dry pick-and-flip assembly technique for angle-resolved photoemission spectroscopy (ARPES) of van der Waals heterostructures. By combining Elvacite2552C acrylic resin and 1-ethyl-3-methylimidazolium ionic liquid, we prepared polymers with glass transition temperatures (T_g) ranging from 37 to 100 ℃. The adhesion of the polymer to the 2D crystals was enhanced at [Formula: see text]. By utilizing the difference in [Formula: see text], a 2D heterostructure can be transferred from a high-[Formula: see text] polymer to a lower-[Formula: see text] polymer, which enables flipping its surface upside down. This process is suitable for assembling heterostructures for ARPES, where the top capping layer should be monolayer graphene. The laser-based micro-focused ARPES measurements of 5-layer WTe₂, 3-layer MoTe₂, 2-layer WTe₂/few-layer Cr₂Ge₂Te₆, and twisted double bilayer WTe₂ demonstrate that this process can be utilized as a versatile sample fabrication method for investigating the energy spectra of 2D heterostructures.

Abstract

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