In Situ Imaging of an Anisotropic Layer-by-Layer Phase Transition in Few-Layer MoTe2
Authors:
- 17 January 2023
- journal article
- research article
- Published by American Chemical Society (ACS) in Nano Letters
- Vol. 23 (2) , 677-684
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.Keywords
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Funding Information
- Basic Energy Sciences (DE-SC0020190)
- National Research Foundation of Korea (2017R1A5A1014862, NRF-2021M3F3A2A01037858, NRF-2021R1A2C3014316)
- Japan Society for the Promotion of Science (19H05790, 20H00354)
- Seoul National University
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