Identification of Polytypism and Their Dislocations in Bilayer MoS2 Using Correlative Transmission Electron Microscopy and Raman Spectroscopy

Fuente: arXiv
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Hauptverfasser: Zhou, Xin, Dierke, Tobias, Wu, Mingjian, You, Shengbo, Götz, Klaus, Unruh, Tobias, Pelz, Philipp, Will, Johannes, Maultzsch, Janina, Spiecker, Erdmann
Format: Preprint
Veröffentlicht: 2025
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author Zhou, Xin
Dierke, Tobias
Wu, Mingjian
You, Shengbo
Götz, Klaus
Unruh, Tobias
Pelz, Philipp
Will, Johannes
Maultzsch, Janina
Spiecker, Erdmann
author_facet Zhou, Xin
Dierke, Tobias
Wu, Mingjian
You, Shengbo
Götz, Klaus
Unruh, Tobias
Pelz, Philipp
Will, Johannes
Maultzsch, Janina
Spiecker, Erdmann
contents Stacking orders and topological defects substantially influence the physical properties of 2D van der Waals (vdW) materials. However, the inherent features of 2D materials challenge the effectiveness of single characterization techniques in identifying stacking sequences, necessitating correlative approaches. Using bilayer MoS2 as a benchmark, we differentiate its polytypism and specific dislocations through transmission electron microscopy (TEM) and Raman spectroscopy. Perfect and partial dislocations were revealed in TEM, which are closely linked to the stacking sequences, thus indirectly indicating the 2H and 3R polytypes. 3D electron diffraction reconstruction on relrods and low-frequency Raman spectroscopy further validated these polytypes owing to their reliance on crystal symmetry. Surprisingly, we unexpectedly resolved both polytypes despite starting with 2H bulk crystal, pointing to a possible phase transition during mechanical exfoliation. The correlative TEM-Raman approach can be extended to other 2D materials, paving the way for property alteration via stacking and defect engineering.
format Preprint
id arxiv_https___arxiv_org_abs_2502_11977
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Identification of Polytypism and Their Dislocations in Bilayer MoS2 Using Correlative Transmission Electron Microscopy and Raman Spectroscopy
Zhou, Xin
Dierke, Tobias
Wu, Mingjian
You, Shengbo
Götz, Klaus
Unruh, Tobias
Pelz, Philipp
Will, Johannes
Maultzsch, Janina
Spiecker, Erdmann
Materials Science
Stacking orders and topological defects substantially influence the physical properties of 2D van der Waals (vdW) materials. However, the inherent features of 2D materials challenge the effectiveness of single characterization techniques in identifying stacking sequences, necessitating correlative approaches. Using bilayer MoS2 as a benchmark, we differentiate its polytypism and specific dislocations through transmission electron microscopy (TEM) and Raman spectroscopy. Perfect and partial dislocations were revealed in TEM, which are closely linked to the stacking sequences, thus indirectly indicating the 2H and 3R polytypes. 3D electron diffraction reconstruction on relrods and low-frequency Raman spectroscopy further validated these polytypes owing to their reliance on crystal symmetry. Surprisingly, we unexpectedly resolved both polytypes despite starting with 2H bulk crystal, pointing to a possible phase transition during mechanical exfoliation. The correlative TEM-Raman approach can be extended to other 2D materials, paving the way for property alteration via stacking and defect engineering.
title Identification of Polytypism and Their Dislocations in Bilayer MoS2 Using Correlative Transmission Electron Microscopy and Raman Spectroscopy
topic Materials Science
url https://arxiv.org/abs/2502.11977