In Situ Imaging of an Anisotropic Layer-by-Layer Phase Transition in Few-Layer MoTe2

Chia Hao Lee; Huije Ryu; Gillian Nolan; Yichao Zhang; Yangjin Lee; Siwon Oh; Hyeonsik Cheong; Kenji Watanabe; Takashi Taniguchi; Kwanpyo Kim; Gwan Hyoung Lee; Pinshane Y. Huang

doi:10.1021/acs.nanolett.2c04550

In Situ Imaging of an Anisotropic Layer-by-Layer Phase Transition in Few-Layer MoTe₂

Chia Hao Lee, Huije Ryu, Gillian Nolan, Yichao Zhang, Yangjin Lee, Siwon Oh, Hyeonsik Cheong, Kenji Watanabe, Takashi Taniguchi, Kwanpyo Kim, Gwan Hyoung Lee, Pinshane Y. Huang

Research output: Contribution to journal › Article › peer-review

Abstract

Understanding the phase transition mechanisms in two-dimensional (2D) materials is a key to precisely tailor their properties at the nanoscale. Molybdenum ditelluride (MoTe₂) exhibits multiple phases at room temperature, making it a promising candidate for phase-change applications. Here, we fabricate lateral 2H-T_d interfaces with laser irradiation and probe their phase transitions from micro- to atomic scales with in situ heating in the transmission electron microscope (TEM). By encapsulating the MoTe₂ with graphene protection layers, we create an in situ reaction cell compatible with atomic resolution imaging. We find that the T_d-to-2H phase transition initiates at phase boundaries at low temperatures (200-225 °C) and propagates anisotropically along the b-axis in a layer-by-layer fashion. We also demonstrate a fully reversible 2H-T_d-2H phase transition cycle, which generates a coherent 2H lattice containing inversion domain boundaries. Our results provide insights on fabricating 2D heterophase devices with atomically sharp and coherent interfaces.

Original language	English
Pages (from-to)	677-684
Number of pages	8
Journal	Nano letters
Volume	23
Issue number	2
DOIs	https://doi.org/10.1021/acs.nanolett.2c04550
Publication status	Published - 2023 Jan 25

Bibliographical note

Funding Information:
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under award number DE-SC0020190, which supported the electron microscopy and related data analysis. This work was carried out in part in the Materials Research Laboratory Central Facilities at the University of Illinois at Urbana–Champaign. G.-H.L. acknowledges support by the Creative-Pioneering Researchers Program through Seoul National University (SNU), the National Research Foundation (NRF) of Korea (NRF-2021R1A2C3014316, SRC program: vdWMRC center 2017R1A5A1014862, NRF-2021M3F3A2A01037858), the Research Institute of Advanced Materials (RIAM), Institute of Engineering Research, Inter-university of Semiconductor Research Center, and Institute of Applied Physics at SNU, which supported the sample fabrication and ex situ characterization. K.W. and T.T. acknowledge support from the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant Numbers 19H05790 and 20H00354) and A3 Foresight by JSPS, which supported the h-BN synthesis.

Funding Information:
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under award number DE-SC0020190, which supported the electron microscopy and related data analysis. This work was carried out in part in the Materials Research Laboratory Central Facilities at the University of Illinois at Urbana-Champaign. G.-H.L. acknowledges support by the Creative-Pioneering Researchers Program through Seoul National University (SNU), the National Research Foundation (NRF) of Korea (NRF-2021R1A2C3014316, SRC program: vdWMRC center 2017R1A5A1014862, NRF-2021M3F3A2A01037858), the Research Institute of Advanced Materials (RIAM), Institute of Engineering Research, Inter-university of Semiconductor Research Center, and Institute of Applied Physics at SNU, which supported the sample fabrication and ex situ characterization. K.W. and T.T. acknowledge support from the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant Numbers 19H05790 and 20H00354) and A3 Foresight by JSPS, which supported the h-BN synthesis.

Publisher Copyright:
© 2023 American Chemical Society.

All Science Journal Classification (ASJC) codes

Bioengineering
Chemistry(all)
Materials Science(all)
Condensed Matter Physics
Mechanical Engineering

Access to Document

10.1021/acs.nanolett.2c04550

Cite this

@article{0125af45af654414a48295a79ae1eb0e,

title = "In Situ Imaging of an Anisotropic Layer-by-Layer Phase Transition in Few-Layer MoTe2",

abstract = "Understanding the phase transition mechanisms in two-dimensional (2D) materials is a key to precisely tailor their properties at the nanoscale. Molybdenum ditelluride (MoTe2) exhibits multiple phases at room temperature, making it a promising candidate for phase-change applications. Here, we fabricate lateral 2H-Td interfaces with laser irradiation and probe their phase transitions from micro- to atomic scales with in situ heating in the transmission electron microscope (TEM). By encapsulating the MoTe2 with graphene protection layers, we create an in situ reaction cell compatible with atomic resolution imaging. We find that the Td-to-2H phase transition initiates at phase boundaries at low temperatures (200-225 °C) and propagates anisotropically along the b-axis in a layer-by-layer fashion. We also demonstrate a fully reversible 2H-Td-2H phase transition cycle, which generates a coherent 2H lattice containing inversion domain boundaries. Our results provide insights on fabricating 2D heterophase devices with atomically sharp and coherent interfaces.",

author = "Lee, {Chia Hao} and Huije Ryu and Gillian Nolan and Yichao Zhang and Yangjin Lee and Siwon Oh and Hyeonsik Cheong and Kenji Watanabe and Takashi Taniguchi and Kwanpyo Kim and Lee, {Gwan Hyoung} and Huang, {Pinshane Y.}",

note = "Funding Information: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under award number DE-SC0020190, which supported the electron microscopy and related data analysis. This work was carried out in part in the Materials Research Laboratory Central Facilities at the University of Illinois at Urbana–Champaign. G.-H.L. acknowledges support by the Creative-Pioneering Researchers Program through Seoul National University (SNU), the National Research Foundation (NRF) of Korea (NRF-2021R1A2C3014316, SRC program: vdWMRC center 2017R1A5A1014862, NRF-2021M3F3A2A01037858), the Research Institute of Advanced Materials (RIAM), Institute of Engineering Research, Inter-university of Semiconductor Research Center, and Institute of Applied Physics at SNU, which supported the sample fabrication and ex situ characterization. K.W. and T.T. acknowledge support from the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant Numbers 19H05790 and 20H00354) and A3 Foresight by JSPS, which supported the h-BN synthesis. Funding Information: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under award number DE-SC0020190, which supported the electron microscopy and related data analysis. This work was carried out in part in the Materials Research Laboratory Central Facilities at the University of Illinois at Urbana-Champaign. G.-H.L. acknowledges support by the Creative-Pioneering Researchers Program through Seoul National University (SNU), the National Research Foundation (NRF) of Korea (NRF-2021R1A2C3014316, SRC program: vdWMRC center 2017R1A5A1014862, NRF-2021M3F3A2A01037858), the Research Institute of Advanced Materials (RIAM), Institute of Engineering Research, Inter-university of Semiconductor Research Center, and Institute of Applied Physics at SNU, which supported the sample fabrication and ex situ characterization. K.W. and T.T. acknowledge support from the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant Numbers 19H05790 and 20H00354) and A3 Foresight by JSPS, which supported the h-BN synthesis. Publisher Copyright: {\textcopyright} 2023 American Chemical Society.",

year = "2023",

month = jan,

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doi = "10.1021/acs.nanolett.2c04550",

language = "English",

volume = "23",

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T1 - In Situ Imaging of an Anisotropic Layer-by-Layer Phase Transition in Few-Layer MoTe2

AU - Lee, Chia Hao

AU - Ryu, Huije

AU - Nolan, Gillian

AU - Zhang, Yichao

AU - Lee, Yangjin

AU - Oh, Siwon

AU - Cheong, Hyeonsik

AU - Watanabe, Kenji

AU - Taniguchi, Takashi

AU - Kim, Kwanpyo

AU - Lee, Gwan Hyoung

AU - Huang, Pinshane Y.

N1 - Funding Information: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under award number DE-SC0020190, which supported the electron microscopy and related data analysis. This work was carried out in part in the Materials Research Laboratory Central Facilities at the University of Illinois at Urbana–Champaign. G.-H.L. acknowledges support by the Creative-Pioneering Researchers Program through Seoul National University (SNU), the National Research Foundation (NRF) of Korea (NRF-2021R1A2C3014316, SRC program: vdWMRC center 2017R1A5A1014862, NRF-2021M3F3A2A01037858), the Research Institute of Advanced Materials (RIAM), Institute of Engineering Research, Inter-university of Semiconductor Research Center, and Institute of Applied Physics at SNU, which supported the sample fabrication and ex situ characterization. K.W. and T.T. acknowledge support from the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant Numbers 19H05790 and 20H00354) and A3 Foresight by JSPS, which supported the h-BN synthesis. Funding Information: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under award number DE-SC0020190, which supported the electron microscopy and related data analysis. This work was carried out in part in the Materials Research Laboratory Central Facilities at the University of Illinois at Urbana-Champaign. G.-H.L. acknowledges support by the Creative-Pioneering Researchers Program through Seoul National University (SNU), the National Research Foundation (NRF) of Korea (NRF-2021R1A2C3014316, SRC program: vdWMRC center 2017R1A5A1014862, NRF-2021M3F3A2A01037858), the Research Institute of Advanced Materials (RIAM), Institute of Engineering Research, Inter-university of Semiconductor Research Center, and Institute of Applied Physics at SNU, which supported the sample fabrication and ex situ characterization. K.W. and T.T. acknowledge support from the Japan Society for the Promotion of Science (JSPS) KAKENHI (Grant Numbers 19H05790 and 20H00354) and A3 Foresight by JSPS, which supported the h-BN synthesis. Publisher Copyright: © 2023 American Chemical Society.

PY - 2023/1/25

Y1 - 2023/1/25

N2 - Understanding the phase transition mechanisms in two-dimensional (2D) materials is a key to precisely tailor their properties at the nanoscale. Molybdenum ditelluride (MoTe2) exhibits multiple phases at room temperature, making it a promising candidate for phase-change applications. Here, we fabricate lateral 2H-Td interfaces with laser irradiation and probe their phase transitions from micro- to atomic scales with in situ heating in the transmission electron microscope (TEM). By encapsulating the MoTe2 with graphene protection layers, we create an in situ reaction cell compatible with atomic resolution imaging. We find that the Td-to-2H phase transition initiates at phase boundaries at low temperatures (200-225 °C) and propagates anisotropically along the b-axis in a layer-by-layer fashion. We also demonstrate a fully reversible 2H-Td-2H phase transition cycle, which generates a coherent 2H lattice containing inversion domain boundaries. Our results provide insights on fabricating 2D heterophase devices with atomically sharp and coherent interfaces.

AB - Understanding the phase transition mechanisms in two-dimensional (2D) materials is a key to precisely tailor their properties at the nanoscale. Molybdenum ditelluride (MoTe2) exhibits multiple phases at room temperature, making it a promising candidate for phase-change applications. Here, we fabricate lateral 2H-Td interfaces with laser irradiation and probe their phase transitions from micro- to atomic scales with in situ heating in the transmission electron microscope (TEM). By encapsulating the MoTe2 with graphene protection layers, we create an in situ reaction cell compatible with atomic resolution imaging. We find that the Td-to-2H phase transition initiates at phase boundaries at low temperatures (200-225 °C) and propagates anisotropically along the b-axis in a layer-by-layer fashion. We also demonstrate a fully reversible 2H-Td-2H phase transition cycle, which generates a coherent 2H lattice containing inversion domain boundaries. Our results provide insights on fabricating 2D heterophase devices with atomically sharp and coherent interfaces.

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