Optical spectroscopy of interlayer coupling in artificially stacked MoS
                    <sub>2</sub>
                    layers

Plechinger, Gerd; Mooshammer, Fabian; Castellanos-Gómez, Andrés; Steele, Gary A.; Schüller, Christian; Korn, Tobias

doi:10.1088/2053-1583/2/3/034016

Cited by 21 publications

(23 citation statements)

References 58 publications

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“…None of the samples showed indications of degradation when stored in ambient conditions for several weeks. Raman measurements of the samples are carried out at room temperature in backscattering geometry with a linearly polarized 532 nm cw laser which is coupled into a 100× microscope objective (spot size 1 µm), further experimental details are published elsewhere . All Raman measurements are performed in cross‐polarized geometry to suppress the spectrally broad background of inelastically scattered light which stems from free carriers in the heavily p‐doped Si substrate .…”

Section: Methodsmentioning

confidence: 99%

Observation of anisotropic interlayer Raman modes in few‐layer ReS₂

Nagler

Plechinger

Schüller

et al. 2015

Physica Rapid Research Ltrs

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ReS$_2$ has recently emerged as a new member in the rapidly growing family of two-dimensional materials. Unlike MoS$_2$ or WSe$_2$, the optical and electrical properties of ReS$_2$ are not isotropic due to the reduced symmetry of the crystal. Here, we present layer-dependent Raman measurements of ReS$_2$ samples ranging from monolayers to ten layers in the ultralow frequency regime. We observe layer breathing and shear modes which allow for easy assignment of the number of layers. Polarization-dependent measurements give further insight into the crystal structure and reveal an energetic shift of the shear mode which stems from the in-plane anisotropy of the shear modulus in this material

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Section: Methodsmentioning

confidence: 99%

Observation of anisotropic interlayer Raman modes in few‐layer ReS₂

Nagler

Plechinger

Schüller

et al. 2015

Physica Rapid Research Ltrs

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“…Particularly, the interlayer shear mode has proven as a very sensitive measure for the interlayer coupling in artificially stacked bi-and multilayers [153] as well as for the dependence of the interlayer coupling strength from the twist angel between two monolayers [154] . Not only for monolithic devices but also for van der Waals hetero bi-and multilayers, the interlayer coupling strength can be evaluated by the energy of the interlayer shear and breathing modes [155] .…”

Section: First Order Phonon Modes As Unique Fingerprint For Materials...mentioning

confidence: 99%

Light–matter interaction in transition metal dichalcogenides and their heterostructures

Wurstbauer¹,

Miller²,

Parzinger³

et al. 2017

J. Phys. D: Appl. Phys.

106

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Abstract:The investigation of two-dimensional van der Waals materials is a vibrant, fast moving and still growing interdisciplinary area of research. Two-dimensional van der Waals materials are truly two-dimensional crystals with strong covalent in-plane bonds and weak van der Waals interaction between the layers with a variety of different electronic, optical and mechanical properties. A very prominent class of twodimensional materials are transition metal dichalcogenides and amongst them particularly the semiconducting subclass. Their properties include bandgaps in the near-infrared to the visible range, decent charge carrier mobility together with high (photo-)catalytic and mechanical stability and exotic many body phenomena. These characteristics make the materials highly attractive for both fundamental research as well as innovative device applications. Furthermore, the materials exhibit a strong light matter interaction providing a high sun light absorbance of up to 15% in the monolayer limit, strong scattering cross section in Raman experiments and access to excitonic phenomena in van der Waals heterostructures. This review focuses on the light matter interaction in MoS2, WS2, MoSe2, and WSe2 that is dictated by the materials complex dielectric functions and on the multiplicity of studying the first order phonon modes by Raman spectroscopy to gain access to several material properties such as doping, strain, defects and temperature. Two-dimensional materials provide an interesting platform to stack them into van der Waals heterostructures without the limitation of lattice mismatch resulting in novel devices for application but also to study exotic many body interaction phenomena such as interlayer excitons. Future perspectives of semiconducting transition metal dichalcogenides and their heterostructures for applications in optoelectronic devices will be examined and routes to study emergent fundamental problems and manybody quantum phenomena under excitations with photons will be discussed.

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“…The PC residuals are finally dissolved in chloroform. Raman spectroscopy measurements were performed in a self-built optical setup, experimental details are published elsewhere [19,24]. Briefly, we utilize a continuouswave laser source with wavelength 532 nm filtered with a narrow bandpass.…”

mentioning

confidence: 99%

Air tightness of hBN encapsulation and its impact on Raman spectroscopy of van der Waals materials

et al. 2019

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Raman spectroscopy is a precious tool for the characterization of van der Waals materials, e.g. for the determination of the layer number in thin exfoliated flakes. For sensitive materials, however, this method can be dramatically invasive. In particular, the light intensity required to obtain a significant Raman signal is sufficient to immediately photo-oxidize few-layer thick metallic van der Waals materials. In this work we investigated the impact of the environment on Raman characterization of thin NbSe2 crystals. We show that in ambient conditions the flake is locally oxidized even for very low illumination intensity. On the other hand, we observe no degradation if the Raman measurements are performed either in vacuum or on fully hBN-encapsulated samples. Interestingly, we find that covering samples deposited on the usual SiO2 surface only from the top is not sufficient to prevent diffusion of oxygen underneath the layers.

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Optical spectroscopy of interlayer coupling in artificially stacked MoS ₂ layers

Cited by 21 publications

References 58 publications

Observation of anisotropic interlayer Raman modes in few‐layer ReS₂

Observation of anisotropic interlayer Raman modes in few‐layer ReS₂

Light–matter interaction in transition metal dichalcogenides and their heterostructures

Air tightness of hBN encapsulation and its impact on Raman spectroscopy of van der Waals materials

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Optical spectroscopy of interlayer coupling in artificially stacked MoS 2 layers

Cited by 21 publications

References 58 publications

Observation of anisotropic interlayer Raman modes in few‐layer ReS2

Observation of anisotropic interlayer Raman modes in few‐layer ReS2

Light–matter interaction in transition metal dichalcogenides and their heterostructures

Air tightness of hBN encapsulation and its impact on Raman spectroscopy of van der Waals materials

Contact Info

Product

Resources

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Optical spectroscopy of interlayer coupling in artificially stacked MoS ₂ layers

Observation of anisotropic interlayer Raman modes in few‐layer ReS₂

Observation of anisotropic interlayer Raman modes in few‐layer ReS₂