2 research outputs found
In Situ Imaging of an Anisotropic Layer-by-Layer Phase Transition in Few-Layer MoTe<sub>2</sub>
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
In Situ Imaging of an Anisotropic Layer-by-Layer Phase Transition in Few-Layer MoTe<sub>2</sub>
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