Two-dimensional (2D) molybdenum ditelluride (MoTe 2 ) is an interesting material for fundamental study and applications, due to its ability to exist in different polymorphs of 2H, 1T, and 1T′, their phase change behavior, and unique electronic properties. Although much progress has been made in the growth of high-quality flakes and films of 2H and 1T′-MoTe 2 phases, phase-selective growth of all three phases remains a huge challenge, due to the lack of enough information on their growth mechanism. Herein, we present a novel approach to growing films and geometrical-shaped few-layer flakes of 2D 2H-, 1T-, and 1T′-MoTe 2 by atmospheric-pressure chemical vapor deposition (APCVD) and present a thorough understanding of the phase-selective growth mechanism by employing the concept of thermodynamics and chemical kinetics involved in the growth processes. Our approach involves optimization of growth parameters and understanding using thermodynamical software, HSC Chemistry. A lattice strain-mediated mechanism has been proposed to explain the phase selective growth of 2D MoTe 2 , and different chemical kinetics-guided strategies have been developed to grow MoTe 2 flakes and films.
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This content will become publicly available on December 1, 2024
Emergent layer stacking arrangements in c-axis confined MoTe2
The layer stacking order in 2D materials strongly affects functional properties and holds promise for next-generation electronic devices. In bulk, octahedral MoTe2possesses two stacking arrangements, the ferroelectric Weyl semimetal Tdphase and the higher-order topological insulator 1T′ phase. However, in thin flakes of MoTe2, it is unclear if the layer stacking follows the Td, 1T′, or an alternative stacking sequence. Here, we use atomic-resolution scanning transmission electron microscopy to directly visualize the MoTe2layer stacking. In thin flakes, we observe highly disordered stacking, with nanoscale 1T′ and Tddomains, as well as alternative stacking arrangements not found in the bulk. We attribute these findings to intrinsic confinement effects on the MoTe2stacking-dependent free energy. Our results are important for the understanding of exotic physics displayed in MoTe2flakes. More broadly, this work suggests
- Award ID(s):
- 2039380
- NSF-PAR ID:
- 10488987
- Publisher / Repository:
- SpringerNature
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 14
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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