Composition and temperature-dependent phase transition in miscible Mo1−xWxTe2 single crystals

Lv, Yang‐Yang; Cao, Lushuai; Xiao, Li; Zhang, Bin-Bin; Wang, Kang; Pang, Bin; Ma, Ligang; Lin, Dongqing; Yao, Shu‐Hua; Zhou, Jian; Chen, Y. B.; Dong, Song‐Tao; Li, Wenchao; Lu, Ming‐Hui; Chen, Yulin; Chen, Yanfeng

doi:10.1038/srep44587

Cited by 64 publications

(45 citation statements)

References 52 publications

(75 reference statements)

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“…13c ). The reason why WS 2 was not produced at this stage is that the bond energy of Sn–S was likely to be lower than that of W–S due to the larger ionic radius of Sn 4+ compared to that of W 4+ 50 , 51 . As the reaction proceeded further, the amount of the Sn 0.17 WO 3 nanorods decreased, and nanosheets started to form on the surfaces of the SnS 2 nanoplates (Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

Realization of vertical metal semiconductor heterostructures via solution phase epitaxy

Wang

Zhang

et al. 2018

Nat Commun

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The creation of crystal phase heterostructures of transition metal chalcogenides, e.g., the 1T/2H heterostructures, has led to the formation of metal/semiconductor junctions with low potential barriers. Very differently, post-transition metal chalcogenides are semiconductors regardless of their phases. Herein, we report, based on experimental and simulation results, that alloying between 1T-SnS2 and 1T-WS2 induces a charge redistribution in Sn and W to realize metallic Sn0.5W0.5S2 nanosheets. These nanosheets are epitaxially deposited on surfaces of semiconducting SnS2 nanoplates to form vertical heterostructures. The ohmic-like contact formed at the Sn0.5W0.5S2/SnS2 heterointerface affords rapid transport of charge carriers, and allows for the fabrication of fast photodetectors. Such facile charge transfer, combined with a high surface affinity for acetone molecules, further enables their use as highly selective 100 ppb level acetone sensors. Our work suggests that combining compositional and structural control in solution-phase epitaxy holds promises for solution-processible thin-film optoelectronics and sensors.

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Section: Resultsmentioning

confidence: 99%

Realization of vertical metal semiconductor heterostructures via solution phase epitaxy

Wang

Zhang

et al. 2018

Nat Commun

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“…This hysteretic behavior has already been reported 76 − 80 and is a signature of a phase transition between the room-temperature metastable monoclinic phase (1T′) and the orthorhombic (T d ) phase, which is stable at lower temperature. 81 , 82 For further investigation of this signature, Raman spectroscopy was also carried out at different temperatures. It has in fact been reported that due to the change of symmetry from 1T′ to T d structure, this phase transition is also accompanied by a splitting of the A g peak at 129 cm –1 (also known as the P 6 peak), in P 6A and P 6B peaks.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Large-Scale Monolayer 1T′-MoTe₂ and Its Stabilization via Scalable hBN Encapsulation

et al. 2021

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Out of the different structural phases of molybdenum ditelluride (MoTe 2 ), the distorted octahedral 1T′ possesses great interest for fundamental physics and is a promising candidate for the implementation of innovative devices such as topological transistors. Indeed, 1T′-MoTe 2 is a semimetal with superconductivity, which has been predicted to be a Weyl semimetal and a quantum spin Hall insulator in bulk and monolayer form, respectively. Large instability of monolayer 1T′-MoTe 2 in environmental conditions, however, has made its investigation extremely challenging so far. In this work, we demonstrate homogeneous growth of large single-crystal (up to 500 μm) monolayer 1T′-MoTe 2 via chemical vapor deposition (CVD) and its stabilization in air with a scalable encapsulation approach. The encapsulant is obtained by electrochemically delaminating CVD hexagonal boron nitride (hBN) from copper foil, and it is applied on the freshly grown 1T′-MoTe 2 via a top-down dry lamination step. The structural and electrical properties of encapsulated 1T′-MoTe 2 have been monitored over several months to assess the degree of degradation of the material. We find that when encapsulated with hBN, the lifetime of monolayer 1T′-MoTe 2 successfully increases from a few minutes to more than a month. Furthermore, the encapsulated monolayer can be subjected to transfer, device processing, and heating and cooling cycles without degradation of its properties. The potential of this scalable heterostack is confirmed by the observation of signatures of low-temperature phase transition in monolayer 1T′-MoTe 2 by both Raman spectroscopy and electrical measurements. The growth and encapsulation methods reported in this work can be employed for further fundamental studies of this enticing material as well as facilitate the technological development of monolayer 1T′-MoTe 2 .

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“…Comparison to experimental results is hindered by the fact, that to the best of our knowledge, all the experimental T'-Mo (1−x) W x Te 2 alloy results are from bulk samples [4,35,36,65]. Monolayer data is only available for pure MoTe 2 and WTe 2 [57][58][59].…”

Section: B T'-(mow)te2mentioning

confidence: 99%

Efficient method for calculating Raman spectra of solids with impurities and alloys and its application to two-dimensional transition metal dichalcogenides

Hashemi

Krasheninnikov

Puska

et al. 2019

Phys. Rev. Materials

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Raman spectroscopy is a widely used, powerful, and nondestructive tool for studying the vibrational properties of bulk and low-dimensional materials. Raman spectra can be simulated using first-principles methods, but due to the high computational cost calculations are usually limited only to fairly small unit cells, which makes it difficult to carry out simulations for alloys and defects. Here, we develop an efficient method for simulating Raman spectra of alloys, benchmark it against full density-functional theory calculations, and apply it to several alloys of two-dimensional transition metal dichalcogenides. In this method, the Raman tensor for the supercell mode is constructed by summing up the Raman tensors of the pristine system weighted by the projections of the supercell vibrational modes to those of the pristine system. This approach is not limited to 2D materials and should be applicable to any crystalline solids with defects and impurities. To efficiently evaluate vibrational modes of very large supercells, we adopt mass approximation, although it is limited to chemically and structurally similar atomic substitutions. To benchmark our method, we first apply it to MoxW (1−x) S2 monolayer in the H-phase, where several experimental reports are available for comparison. Second, we consider MoxW (1−x) Te2 in the T'-phase, which has been proposed to be 2D topological insulator, but where experimental results for the monolayer alloy are still missing. We show that the projection scheme also provides a powerful tool for analyzing the origin of the alloy Raman-active modes in terms of the parent system eigenmodes. Finally, we examine the trends in characteristic Raman signatures for dilute concentrations of impurities in MoS2. :1902.02143v1 [cond-mat.mtrl-sci] arXiv

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Composition and temperature-dependent phase transition in miscible Mo1−xWxTe2 single crystals

Cited by 64 publications

References 52 publications

Realization of vertical metal semiconductor heterostructures via solution phase epitaxy

Realization of vertical metal semiconductor heterostructures via solution phase epitaxy

Synthesis of Large-Scale Monolayer 1T′-MoTe₂ and Its Stabilization via Scalable hBN Encapsulation

Efficient method for calculating Raman spectra of solids with impurities and alloys and its application to two-dimensional transition metal dichalcogenides

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Composition and temperature-dependent phase transition in miscible Mo1−xWxTe2 single crystals

Cited by 64 publications

References 52 publications

Realization of vertical metal semiconductor heterostructures via solution phase epitaxy

Realization of vertical metal semiconductor heterostructures via solution phase epitaxy

Synthesis of Large-Scale Monolayer 1T′-MoTe2 and Its Stabilization via Scalable hBN Encapsulation

Efficient method for calculating Raman spectra of solids with impurities and alloys and its application to two-dimensional transition metal dichalcogenides

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Product

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Synthesis of Large-Scale Monolayer 1T′-MoTe₂ and Its Stabilization via Scalable hBN Encapsulation