Determination of the thickness and orientation of few-layer tungsten ditelluride using polarized Raman spectroscopy

Abstract

Orthorhombic tungsten ditelluride (WTe2), with a distorted 1T structure, exhibits a large magnetoresistance that depends on the orientation, and its electrical characteristics changes rom semimetallic to insulating as the thickness decreases. Through polarized Raman spectroscopy in combination with transmission electron diffraction, we establish a reliable method to determine the thickness and crystallographic orientation of few-layer WTe2. The Raman spectrum shows a pronounced dependence on the polarization of the excitation laser. We found that the separation between two Raman peaks at ~90 cm-1 and at 80-86 cm-1, depending on thickness, is a reliable fingerprint for determination of the thickness. For determination of the crystallographic orientation, the polarization dependence of the A1 modes, measured with the 632.8-nm excitation, turns out to be the most reliable. We also discovered that the polarization behaviors of some of the Raman peaks depend on the excitation wavelength as well as thickness, indicating a close interplay between the band structure and anisotropic Raman scattering cross section.

16 pages, 4 figures

References in corpus (9)

• Anomalous Lattice Vibrations of Single and Few-Layer MoS2
• Titanic Magnetoresistance in WTe2
• Phonon and Raman scattering of two-dimensional transition metal dichalcogenides from monolayer, multilayer to bulk material
• Quantum oscillations, thermoelectric coefficients and the Fermi surface of semi-metallic WTe2
• Anisotropic Magnetotransport and Exotic Longitudinal Linear Magnetoresistance in WTe2 Crystals
• Anomalous excitonic resonance Raman effects in few-layer MoS2
• Double resonance Raman modes in mono- and few-layer MoTe${}_2$
• Excitation Energy Dependent Raman Signatures of ABA- and ABC-stacked Few-layer Graphene
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• Determination of the spin axis in quantum spin Hall insulator monolayer WTe2
• Orbital polarization and third-order anomalous Hall effect in WTe2
• Strong and Tunable Electrical-Anisotropy in Type-II Weyl Semimetal Candidate WP2 with Broken Inversion Symmetry
• Quantitatively predicting angle-resolved polarized Raman intensity of anisotropic layered materials
• Nonlinear spin and orbital Edelstein effect in WTe2
• Unidirectional Alignment of AgCN Microwires on Distorted Transition Metal Dichalcogenide Crystals
• Large change of interlayer vibrational coupling with stacking in Mo${}_{1-x}$W${}_x$Te${}_2$
• Strain-Mediated Lattice Reconstruction Enhances Ferromagnetism in Cr2Ge2Te6/WTe2 van der Waals Heterobilayers