Distinct photoluminescence and Raman spectroscopy signatures for identifying highly crystalline WS<sub>2</sub> monolayers produced by different growth methods

McCreary, Amber; Berkdemir, Ayşe; Wang, Junjie; Nguyen, Minh; Elías, Ana Laura; Perea-López, Néstor; Fujisawa, Kazunori; Kabius, B.; Carôzo, Victor; Cullen, David A.; Mallouk, Thomas E.; Zhu, Jun; Terrones, Mauricio

doi:10.1557/jmr.2016.47

Cited by 97 publications

(125 citation statements)

References 95 publications

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“…It should be noted that the PL intensity of T5 is only 20% of T4. Meanwhile, its peak width of 68 meV is also larger than that of T4 (47 meV), which possibly be induced by high density of defects in T5 [31].…”

Section: Optical Characterization Of Ws 2 /Ti 3 C 2 T X Mxenementioning

confidence: 93%

Growth of WS2 flakes on Ti3C2Tx Mxene Using Vapor Transportation Routine

Wang

et al. 2018

Coatings

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Two-dimensional dichalcogenides (TMDs) and mxene junctions had been predicted to possess distinct tunable electronic properties. However, direct synthesis of WS 2 on Ti 3 C 2 T x mxene is still challenging. Herein, we successfully deposited WS 2 onto the surface of Ti 3 C 2 T x mxene by employing the vapor transportation (VT) routine. By modulating pressure and source-sample distance, multilayer and monolayer (1 L) WS 2 flakes were deposited onto the lateral side and top surface of Ti 3 C 2 T x flakes. The 1 L WS 2 flakes growing on lateral side of Ti 3 C 2 T x flake have much higher photoluminescence (PL) intensity than 1 L flakes growing on the top surface. Our study has the potential to benefit the design and preparation of novel electronic and electrochemical devices based on TMDs/mxene junctions.

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Section: Optical Characterization Of Ws 2 /Ti 3 C 2 T X Mxenementioning

confidence: 93%

Growth of WS2 flakes on Ti3C2Tx Mxene Using Vapor Transportation Routine

Wang

et al. 2018

Coatings

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“…The peak intensity of the LA(M) mode is summarized in Figure (b), indicating a growing tendency which also reflects an enhancement of lattice disorder. Generally speaking, the lattice defects and unintentional doping are the most likely reason for the emergence of a LA(M) peak at ambient pressure . In the PL spectrum of monolayer WSe 2 , the LA(M) peak at ambient pressure should arise from the unintentional doping‐induced lattice structural disorder.…”

Section: Resultsmentioning

confidence: 99%

“…The A 1 ′ mode originates from transverse vibration of Se−Se atoms and the E′ mode originates from longitudinal vibration of W−Se atoms in opposite directions; they correspond to the A 1g and E 1 2g modes in bulk WSe 2 , respectively . The LA(M) mode is the longitudinal acoustic phonon at the M symmetry point in the Brillouin zone, it is usually activated by lattice structural disorder …”

Section: Resultsmentioning

confidence: 99%

“…It was reported that the intensity of the LA(M) can reflect the lattice disorder degree in the sample . The higher relative intensity of the LA(M) mode reflects a more disordered structure.…”

Section: Resultsmentioning

confidence: 99%

“…[22] The LA(M) mode is the longitudinal acousticp honon at the Ms ymmetry point in the Brillouin zone, [39,[42][43][44] it is usuallya ctivated by lattice structural disorder. [42][43][44][45][46][47][48][49] From the Raman spectra at 0t o3 1.37 GPa, shown in Figure 4, we can see the LA(M) ando ther second order vibrations give ar elatively weak intensity initially,b ut that as the pressure increases the intensity of the LA(M) mode clearly grows.A ll other main Raman peaks give ab roader width at high pressures;t hey are extracted by Lorentz profile function fittings and the pressure evolution of peak positions are summarized. We noticed that the E' vibration abates after the sample was sealed in DAC with pressure applied, and becomes broader after around1 0GPa.…”

Section: Resultsmentioning

confidence: 99%

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Pressure‐Induced Photoluminescence Adjustment and Lattice Disorder in Monolayer WSe₂

et al. 2017

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Pressure engineering is considered as a novel strategy to modulate the properties of transition metal dichalcogenide materials. Here, through photoluminescence (PL) and Raman measurements, we investigate the electronic band structure variation and lattice vibrational dynamics of monolayer tungsten diselenide (WSe2) under pressure. As the pressure increases, the energy of the direct Κ→Κ interband transition increases, whereas that of the indirect Λ→Κ interband transition decreases, leading to a significant transition from direct to indirect band gap at 3.8 GPa. With the increase of pressure, the intensity of the direct Κ→Κ interband transition constantly decreases and finally vanishes around 12.2 GPa. Moreover, a remarkable transition between A′ and LA(M) modes under pressure has been determined by virtue of Raman spectra variations, which indicate a pressure‐induced lattice disorder. This work provides a deep understanding of the intrinsic variation of WSe2 under pressure, which effectively facilitates the development of device applications.

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Defect Engineering in Ambipolar Layered Materials for Mode‐Regulable Nociceptor

Yang

Hsu

et al. 2020

Adv Funct Materials

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Defect engineering represents a significant approach for atomically thick 2D semiconductor material development to explore the unique material properties and functions. Doping‐induced conversion of conductive polarity is particularly beneficial for optimizing the integration of layered electronics. Here, controllable doping behavior in palladium diselenide (PdSe2) transistor is demonstrated by manipulating its adatom‐vacancy groups. The underlying mechanisms, which originate from reversible adsorption/desorption of oxygen clusters near selenide vacancy defects, are investigated systematically via their dynamic charge transfer characteristics and scanning tunneling microscope analysis. The modulated doping effect allows the PdSe2 transistor to emulate the essential characteristics of photo nociceptor on a device level, including firing signal threshold and sensitization. Interestingly, electrostatic gating, acting as a neuromodulator, can regulate the adaptive modes in nociceptor to improve its adaptability and perceptibility to handle different danger levels. An integrated artificial nociceptor array is also designed to execute unique image processing functions, which suggests a new perspective for extension of the promise of defect engineered 2D electronics in simplified sensory systems toward use in advanced humanoid robots and artificial visual sensors.

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Distinct photoluminescence and Raman spectroscopy signatures for identifying highly crystalline WS₂ monolayers produced by different growth methods

Abstract: Abstract

Cited by 97 publications

References 95 publications

Growth of WS2 flakes on Ti3C2Tx Mxene Using Vapor Transportation Routine

Growth of WS2 flakes on Ti3C2Tx Mxene Using Vapor Transportation Routine

Pressure‐Induced Photoluminescence Adjustment and Lattice Disorder in Monolayer WSe₂

Defect Engineering in Ambipolar Layered Materials for Mode‐Regulable Nociceptor

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Distinct photoluminescence and Raman spectroscopy signatures for identifying highly crystalline WS2 monolayers produced by different growth methods

Abstract: Abstract

Cited by 97 publications

References 95 publications

Growth of WS2 flakes on Ti3C2Tx Mxene Using Vapor Transportation Routine

Growth of WS2 flakes on Ti3C2Tx Mxene Using Vapor Transportation Routine

Pressure‐Induced Photoluminescence Adjustment and Lattice Disorder in Monolayer WSe2

Defect Engineering in Ambipolar Layered Materials for Mode‐Regulable Nociceptor

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Product

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Distinct photoluminescence and Raman spectroscopy signatures for identifying highly crystalline WS₂ monolayers produced by different growth methods

Pressure‐Induced Photoluminescence Adjustment and Lattice Disorder in Monolayer WSe₂