Anisotropic Raman scattering and mobility in monolayer 1T d -ReS 2 controlled by strain engineering

Zhou, Zhenjia; Wei, Bochao; He, Chao; Min, Yuho; Chen, C.H.; Liu, L.Z.; Wu, Xiaoqiang

doi:10.1016/j.apsusc.2017.01.305

Cited by 24 publications

(20 citation statements)

References 33 publications

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“…Recently, the electrical transport properties of n-type field effect transistor devices have been reported to be strongly anisotropic [8,35,36], and the conduction band electron mobility was found to be about three times larger along the rhenium chains compared to the direction perpendicular to them [8]. In the Supplemental Material, Fig.…”

Section: Resultsmentioning

confidence: 99%

Electronic band structure of ReS2 by high-resolution angle-resolved photoemission spectroscopy

et al. 2017

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The rhenium-based transition metal dichalcogenides (TMDs) are atypical of the TMD family due to their highly anisotropic crystalline structure and are recognized as promising materials for two-dimensional heterostructure devices. The nature of the band gap (direct or indirect) for bulk, few-, and single-layer forms of ReS 2 is of particular interest, due to its comparatively weak interplanar interaction. However, the degree of interlayer interaction and the question of whether a transition from indirect to direct gap is observed on reducing thickness (as in other TMDs) are controversial. We present a direct determination of the valence band structure of bulk ReS 2 using high-resolution angle-resolved photoemission spectroscopy. We find a clear in-plane anisotropy due to the presence of chains of Re atoms, with a strongly directional effective mass which is larger in the direction orthogonal to the Re chains (2.2m e ) than along them (1.6m e ). An appreciable interplane interaction results in an experimentally measured difference of ≈100−200 meV between the valence band maxima at the Z point (0,0, 1 2 ) and the point (0,0,0) of the three-dimensional Brillouin zone. This leads to a direct gap at Z and a close-lying but larger gap at , implying that bulk ReS 2 is marginally indirect. This may account for recent conflicting transport and photoluminescence measurements and the resulting uncertainty about the nature of the band gap in this material.

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Section: Resultsmentioning

confidence: 99%

Electronic band structure of ReS2 by high-resolution angle-resolved photoemission spectroscopy

et al. 2017

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“…Previous reports have suggested that the E g -3 mode involves out-of-plane vibrations of the S atoms along with in-plane vibrations of Re atoms and that the A 1g -4 mode results from the out-of-plane vibrations of S atoms. 10,15 As the distortion of Re4 units occurs at a much lower pressure (6.8 GPa), as discussed above, the splitting phenomena at 15.4 GPa should be attributed to the changes of force constants of S atoms. Previous theoretical calculations have indicated that ambient ReS 2 is randomly stacked, because shifting one ReS 2 monolayer over another does not lead to any significant change in total energy owing to its weak interlayer coupling.…”

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confidence: 83%

Associated Lattice and Electronic Structural Evolutions in Compressed Multilayer ReS₂

Yan

Jin

Wang

et al. 2017

J. Phys. Chem. Lett.

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The transition metal dichalcogenide (TMD) ReS is a promising material for optoelectronic devices because of its remarkable quantum yield. Pressure can effectively tune the optoelectronic properties of TMDs through control of the atomic displacement. Here, we systematically investigated the lattice and electronic structural evolutions of compressed multilayer ReS. Both Raman spectra and first-principles calculations suggest the occurrence of an intralayer phase transition followed by an interlayer transition. A transition from one indirect to another indirect bandgap at 2.7 GPa was revealed by both high-pressure photoluminescence (PL) measurements and first-principles calculations, this behavior was elucidated by considering the fundamental relationship between lattice variation and electronic evolution. Moreover, by comparing the high-pressure behavior of MoS and ReS, we demonstrated interlayer coupling plays a critical role in determining the lattice and electronic structures in compressed TMDs. Our findings suggest the potential application of ReS in fabricating various stacking devices with tailored properties.

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“…For ReS 2 materials, there are 36 vibrational modes which can be written as Γ Raman = 18(A g + A u ) being the cause of 12 atoms in the primitive cell . Getting rid of 15 infrared-active modes and 3 zero-frequency modes, the 18 Raman-active modes which belong to the symmetric A g modes can be detected. , All the Raman-active modes of the ReS 2 films are shown in Figure . These Raman spectra of the ReS 2 films display more complex peaks than those of conventional TMDs such as MoS 2 and WS 2 .…”

Section: Results and Discussionmentioning

confidence: 99%

Temperature Dependence of Phonon Modes, Optical Constants, and Optical Band Gap in Two-Dimensional ReS₂ Films

et al. 2018

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Effects of temperature on the optical properties of large-area ReS2 films (10 layers), which are prepared by chemical vapor deposition, have been investigated by Raman and reflectance spectra. The phonon frequencies of 18 Raman modes red-shift about 3 cm–1 by increasing the temperature from 140 to 320 K. The optical constants (n and k) at a photon energy region of 0.46–6.52 eV are obtained, and the values blue-shift with increasing temperature. Four interband transitions (E p1, E p2, E p3, and E p4) are observed at 1.53, 2.98, 4.25, and 5.37 eV at 303 K, respectively, and the values increase with increasing the temperature. The physical origins have been assigned to the different band-to-band direct electronic transitions. The optical band gap of the ReS2 films increases from 1.36 eV at 303 K to 1.38 eV at 383 K. Based on the first-principles calculation results, the band gap increases from 1.32 eV at a normal lattice constant to 1.40 eV at 1.1 times lattice constant. This is because the energy levels present the tendencies of degeneracy, due to which the coupling between the Re 5d orbital and S 3p orbital is weaker and the energy level splitting is smaller with increasing temperature.

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Anisotropic Raman scattering and mobility in monolayer 1T d -ReS 2 controlled by strain engineering

Cited by 24 publications

References 33 publications

Electronic band structure of ReS2 by high-resolution angle-resolved photoemission spectroscopy

Electronic band structure of ReS2 by high-resolution angle-resolved photoemission spectroscopy

Associated Lattice and Electronic Structural Evolutions in Compressed Multilayer ReS₂

Temperature Dependence of Phonon Modes, Optical Constants, and Optical Band Gap in Two-Dimensional ReS₂ Films

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Anisotropic Raman scattering and mobility in monolayer 1T d -ReS 2 controlled by strain engineering

Cited by 24 publications

References 33 publications

Electronic band structure of ReS2 by high-resolution angle-resolved photoemission spectroscopy

Electronic band structure of ReS2 by high-resolution angle-resolved photoemission spectroscopy

Associated Lattice and Electronic Structural Evolutions in Compressed Multilayer ReS2

Temperature Dependence of Phonon Modes, Optical Constants, and Optical Band Gap in Two-Dimensional ReS2 Films

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Product

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Associated Lattice and Electronic Structural Evolutions in Compressed Multilayer ReS₂

Temperature Dependence of Phonon Modes, Optical Constants, and Optical Band Gap in Two-Dimensional ReS₂ Films