Resonance Raman spectroscopy as a probe of the crystallite size of MoS2 nanoparticles

Blanco, Élodie; Afanasiev, P.; Berhault, Gilles; Uzio, Denis; Loridant, S.

doi:10.1016/j.crci.2015.08.014

Cited by 60 publications

(40 citation statements)

References 28 publications

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“…Figure 10. The Raman spectra with two characteristic modes of vibrations at E 1 2g at 378 cm −1 and A 1 g at 407 cm −1 , in agreement with Kong et al [19].…”

Section: Nanoscale Mechanical Propertiessupporting

confidence: 90%

“…Energy disperse confirms Sulfur-Kα (60%) and Molybdenum-Lα (40%) at 2.4 keV signal; and Raman spectroscopy modes of vibration at surface corresponding to E 1 2g = 378 cm −1 and A 1 g = 407 cm −1 . From high-resolution STEM it was possible to determine a degree of stacking between 7 layers along (002)-basal plane and to confirm vertical growth in agreement with Kong et al [19], and APT preliminary measurements indicate a large quantity of sulfur and molybdenum with no grain boundaries or high impurities within film matrix for specific thin film growth using RF-sputtering conditions. From electrical transport measurements, it was possible to determine a linear Ohmic behavior and excitation when external visible light was on and off during four-point probe measurements as indicated by Figure 16, the resistivity values 26.5 Ω/m versus 35.0 Ω/m for off and on in external visible light, as possible caused by intrinsic semiconductor nature of MoS 2 in agreement with [2,32,33].…”

Section: Discussionsupporting

confidence: 69%

See 1 more Smart Citation

MoS₂ Thin Films for Photo-Voltaic Applications

Ramos¹,

Nogan²,

Ortíz-Díaz³

et al. 2019

2D Materials

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The low dimensional chalcogenide materials with high band gap of ~1.8 eV, specially molybdenum di-sulfide (MoS 2), have been brought much attention in the material science community for their usage as semiconducting materials to fabricate low scaled electronic devices with high throughput and reliability, this includes also photovoltaic applications. In this chapter, experimental data for MoS 2 material towards developing the next generation of high-efficiency solar cells is presented, which includes fabrication of ~100 nm homogeneous thin film over silicon dioxide (SiO 2) by using radio frequency sputtering at 275 W at high vacuum~10 −9 from commercial MoS 2 99.9% purity target. The films were studied by means of scanning and transmission electron microscopy with energy disperse spectroscopy, grazing incident low angle x-ray scattering, Raman spectroscopy, atomic force microscopy, atom probe tomography, electrical transport using four-point probe resistivity measurement as well mechanical properties utilizing nano-indentation with continuous stiffness mode (CSM) approach. The experimental results indicate a vertical growth direction at (101)-MoS 2 crystallites with stacking values of 7-laminates along the (002)-basal plane; principal Raman vibrations at E 1 2g at 378 cm −1 and A 1 g at 407 cm −1. The hardness and elastic modulus values of H = 10.5 ± 0.1 GPa and E = 136 ± 2 GPa were estimated by CSM method from 0 to 90 nm of indenter penetration; as well transport measurements from −3.5 V to +3.5 V indicating linear Ohmic behavior.

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“…Figure 10. The Raman spectra with two characteristic modes of vibrations at E 1 2g at 378 cm −1 and A 1 g at 407 cm −1 , in agreement with Kong et al [19].…”

Section: Nanoscale Mechanical Propertiessupporting

confidence: 90%

Section: Discussionsupporting

confidence: 69%

MoS₂ Thin Films for Photo-Voltaic Applications

Ramos¹,

Nogan²,

Ortíz-Díaz³

et al. 2019

2D Materials

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“…Raman spectroscopy was utilized to characterize crystal phase and structural features of Redoped MoS2 samples. As shown in Figure 3, Raman spectra of all samples display the typical two main lines of 2H-MoS2, corresponding to out-of-plane A1g mode, and an in-plane E 1 2g mode, observed at approximately 409-400 cm −1 and 382-371 cm −1 , respectively [23,26]. By the increase of rhenium content, a remarkable line broadening is observed in the first-order Raman signals.…”

Section: Raman Spectroscopy Analysismentioning

confidence: 85%

“…Additionally, the intensity of the broadened band in the region between 100 and 250 cm −1 can also be attributed to Re content in the samples [28]. In this sense, the rhenium content could affect this Raman region through formation of a ReS 2 single phase (ReS 2 Raman active strongest vibrations are located in the range of 120 to 240 cm −1 ) [29,30] by inducing changes in the MoS 2 phase (from 2H to 1T/1T d ) [16,18,31] or by defect-induced scattering of the MoS 2 small/disordered particles (low-frequency defect-activated modes) [26,28,32]. The overlapping frequencies of these variables preclude a particular identification for the origin of these bands.…”

Section: Raman Spectroscopy Analysismentioning

confidence: 99%

Electrochemical Hydrogen Evolution over Hydrothermally Synthesized Re-Doped MoS2 Flower-Like Microspheres

et al. 2019

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In this research, we report a simple hydrothermal synthesis to prepare rhenium (Re)- doped MoS2 flower-like microspheres and the tuning of their structural, electronic, and electrocatalytic properties by modulating the insertion of Re. The obtained compounds were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Structural, morphological, and chemical analyses confirmed the synthesis of poorly crystalline Re-doped MoS2 flower-like microspheres composed of few stacked layers. They exhibit enhanced hydrogen evolution reaction (HER) performance with low overpotential of 210 mV at current density of 10 mA/cm2, with a small Tafel slope of 78 mV/dec. The enhanced catalytic HER performance can be ascribed to activation of MoS2 basal planes and by reduction in charge transfer resistance during HER upon doping.

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“…The mild modification (L:MoS 2 ≤0.2) likely heals the SVs, resulting in a more robust crystal structure of MoS 2 , while the heavy modification (L:MoS 2 >0.2) introduces local strain, which might weaken the intralayer bonds of MoS 2 , rendering a relatively vulnerable structure and thus possibly more exposed edges. The change of grain size, caused by the high degree of functionalization when L:MoS 2 >0.2, potentially accounts for the different scaling of the Raman intensity ratio across this point. In other words, without disturbing the integrity of MoS 2 nanosheets, the maximum sulfur vacancy modification can be achieved when about 20 % of surface addends are introduced.…”

Section: Resultsmentioning

confidence: 99%

Defect Engineering of Two‐Dimensional Molybdenum Disulfide

Chen

Denninger

Stimpel‐Lindner

et al. 2020

Chemistry A European J

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Two-dimensional (2D) molybdenum disulfide (MoS 2 )h olds great promise in electronic and optoelectronic applicationso wing to its unique structure and intriguing properties. The intrinsic defects such as sulfur vacancies (SVs) of MoS 2 nanosheets are found to be detrimental to the device efficiency.T om itigate this problem, functionalization of 2D MoS 2 using thiols has emerged as one of the key strategies for engineering defects. Herein,w ed emonstrate an approach to controllably engineer the SVs of chemically exfoliated MoS 2 nanosheets using as eries of substituted thio-phenols in solution. The degree of functionalization can be tuned by varying the electron-withdrawing strength of substituents in thiophenols. We find that the intensity of 2LA(M) peak normalized to A 1g peak strongly correlates to the degree of functionalization. Our resultsp rovide as pectroscopici ndicatort om onitora nd quantify the defecte ngineering process. This methodo fM oS 2 defectf unctionalization in solution also benefitst he further exploration of defect-free MoS 2 for aw ide range of applications.[a] Dr.

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Resonance Raman spectroscopy as a probe of the crystallite size of MoS2 nanoparticles

Cited by 60 publications

References 28 publications

MoS₂ Thin Films for Photo-Voltaic Applications

MoS₂ Thin Films for Photo-Voltaic Applications

Electrochemical Hydrogen Evolution over Hydrothermally Synthesized Re-Doped MoS2 Flower-Like Microspheres

Defect Engineering of Two‐Dimensional Molybdenum Disulfide

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Resonance Raman spectroscopy as a probe of the crystallite size of MoS2 nanoparticles

Cited by 60 publications

References 28 publications

MoS2 Thin Films for Photo-Voltaic Applications

MoS2 Thin Films for Photo-Voltaic Applications

Electrochemical Hydrogen Evolution over Hydrothermally Synthesized Re-Doped MoS2 Flower-Like Microspheres

Defect Engineering of Two‐Dimensional Molybdenum Disulfide

Contact Info

Product

Resources

About

MoS₂ Thin Films for Photo-Voltaic Applications

MoS₂ Thin Films for Photo-Voltaic Applications