Core level spectroscopy of MoS2

Mattila, S.; Leiro, J.A.; Heinonen, M.H.; Laiho, Taina

doi:10.1016/j.susc.2006.08.038

Cited by 41 publications

(45 citation statements)

References 43 publications

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“…The doublet structure of the Mo3d and S2p spectra illustrated in Figure 2 reflects the characteristic spin-orbit splitting between Mo3d 3/2 and 3d 5/2 states and S2p 1/2 and 2p 3/2 , respectively. The peaks of the reference MoS 2 (0001) surface were sharply resolved and symmetric with positions recorded at 229.6 eV for Mo3d 5/2 and at 162.5 eV for S2p 3/2 , in excellent agreement with literature values for MoS 2 (0001) 23 . For the MoS 2 /Au samples the Mo3d 5/2 main peak lies ~0.4 eV lower in BE at 229.2 eV and the approximately same peak shift is also seen in the S2p signals.…”

Section: X-ray Photoemission Spectroscopy At Ultra-high Vacuum Conditsupporting

confidence: 88%

In Situ Detection of Active Edge Sites in Single-Layer MoS₂ Catalysts

et al. 2015

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MoS2 nanoparticles are proven catalysts for processes such as hydrodesulfurization and hydrogen evolution, but unravelling their atomic-scale structure under catalytic working conditions has remained significantly challenging. Ambient pressure X-ray Photoelectron Spectroscopy (AP-XPS) allows us to follow in situ the formation of the catalytically relevant MoS2 edge sites in their active state. The XPS fingerprint is described by independent contributions to the Mo 3d core level spectrum whose relative intensity is sensitive to the thermodynamic conditions. Density Functional Theory (DFT) is used to model the triangular MoS2 particles on Au(111) and identify the particular sulphidation state of the edge sites. A consistent picture emerges in which the core level shifts for the edge Mo atoms evolve counterintuitively toward higher binding energies when the active edges are reduced. The shift is explained by a surprising alteration in the metallic character of the edge sites, which is a distinct spectroscopic signature of the MoS2 edges under working conditions.

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Section: X-ray Photoemission Spectroscopy At Ultra-high Vacuum Conditsupporting

confidence: 88%

In Situ Detection of Active Edge Sites in Single-Layer MoS₂ Catalysts

et al. 2015

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“…The Mo 3d and S 2p spectra were fitted by sums of Voigt curves, i.e, the convolution of a Gaussian (of fullwidth at half-maximum GW) by a Lorentzian (of full-width at halfmaximum LW). The LW was fixed at 90 meV for Mo 3d and S 2p [51]. The Mo 3d peak was reconstituted with a 3d 5/2 :3d 3/2 ratio of 0.66 and a spin-orbit splitting of 3.10 eV.…”

Section: Methodsmentioning

confidence: 99%

Bandgap inhomogeneity of MoS2 monolayer on epitaxial graphene bilayer in van der Waals p-n junction

Aziza

Henck

Felice

et al. 2016

Carbon

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a b s t r a c tAtomically thin MoS 2 /graphene vertical heterostructures are promising candidates for nanoelectronic and optoelectronic technologies. In this work, we studied the optical and electronic properties of n doped single layer MoS 2 on p doped bilayer graphene vdW heterostructures. We demonstrate a non-uniform strain between two different orientation angles of MoS 2 monolayer on top of epitaxial bilayer graphene. A significant downshift of the E 1 2g mode, a slight downshift of the A 1g mode, and photoluminescence shift and quenching are observed between two MoS 2 monolayers differently oriented with respect to graphene; This could be mostly attributed to the strain-induced transition from direct to indirect bandgap in monolayer MoS 2 . Moreover, our theoretical calculations about differently-strained MoS 2 monolayers are in a perfect accordance with the experimentally observed behavior of differently-oriented MoS 2 flakes on epitaxial bilayer graphene. Hence, our results show that straininduced bandgap engineering of single layered MoS 2 is dependent on the orientation angle between stacked layers. These findings could be an interesting novel way to take advantage of the possibilities of MoS 2 and deeply exploit the capabilities of MoS 2 /graphene van der Waals heterostructures.© 2016 Elsevier Ltd. All rights reserved.Ever since the technique to isolate stable single-layer graphene was reported, the study of two-dimensional (2D) materials has gained a lot of research interest. Hence, a broad family of 2D materials like graphene, transition metal dichalcogenides (TMDCs), and topological insulators have been explored so far [1]. For the sake of exploring their fundamental interfacial interactions and conceiving novel electronic functionalities, vertical heterostructures composed of 2D materials stacked together by van der Waals (vdW) forces have attracted a great attention lately [2]. Among these combined structures, the MoS 2 /graphene heterostructure, among other heterostructures combining graphene with different layered 2D materials [3], shows a promising potential for next generation nanoelectronic and optoelectronic devices thanks to the outstanding carrier mobilities on one hand and the excellent optical responsivities on the other hand [4e6].However, research work about the structural quality, the band alignment and the optical emission properties of MoS 2 /graphene or graphene/MoS 2 vdW heterostructures are still limited. The exploration of such characteristic properties are fundamental to make possible the assembling of MoS 2 with graphene, pave the way for the realization of a well-ordered MoS 2 /graphene structure, and enable opportunities for a wide spectrum of optoelectronic functionalities. Inspirations of this present work arise from the fact that some of the theoretical calculations have predicted the crossover between a direct and indirect bandgap of MoS 2 originating from the modification of interlayer orientation [7e9]. Since the properties of MoS 2 /graphene heterostructure depend st...

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“…The LW was fixed at 90 meV for Mo 3d and S 2p. 30 Angle-resolved Photoemission spectroscopy: The ARPES measurements were conducted at the CASSIOPEE beamline of Synchrotron SOLEIL (Saint-Aubin, France). We used horizontally linearly polarized photons of 50 eV and a hemispherical electron analyzer with vertical slits to allow band mapping.…”

Section: Hr-xpsmentioning

confidence: 99%

Tunable Doping in Hydrogenated Single Layered Molybdenum Disulfide

et al. 2017

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Structural defects in the molybdenum disulfide (MoS) monolayer are widely known for strongly altering its properties. Therefore, a deep understanding of these structural defects and how they affect MoS electronic properties is of fundamental importance. Here, we report on the incorporation of atomic hydrogen in monolayered MoS to tune its structural defects. We demonstrate that the electronic properties of single layer MoS can be tuned from the intrinsic electron (n) to hole (p) doping via controlled exposure to atomic hydrogen at room temperature. Moreover, this hydrogenation process represents a viable technique to completely saturate the sulfur vacancies present in the MoS flakes. The successful incorporation of hydrogen in MoS leads to the modification of the electronic properties as evidenced by high resolution X-ray photoemission spectroscopy and density functional theory calculations. Micro-Raman spectroscopy and angle resolved photoemission spectroscopy measurements show the high quality of the hydrogenated MoS confirming the efficiency of our hydrogenation process. These results demonstrate that the MoS hydrogenation could be a significant and efficient way to achieve tunable doping of transition metal dichalcogenides (TMD) materials with non-TMD elements.

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Core level spectroscopy of MoS2

Cited by 41 publications

References 43 publications

In Situ Detection of Active Edge Sites in Single-Layer MoS₂ Catalysts

In Situ Detection of Active Edge Sites in Single-Layer MoS₂ Catalysts

Bandgap inhomogeneity of MoS2 monolayer on epitaxial graphene bilayer in van der Waals p-n junction

Tunable Doping in Hydrogenated Single Layered Molybdenum Disulfide

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Core level spectroscopy of MoS2

Cited by 41 publications

References 43 publications

In Situ Detection of Active Edge Sites in Single-Layer MoS2 Catalysts

In Situ Detection of Active Edge Sites in Single-Layer MoS2 Catalysts

Bandgap inhomogeneity of MoS2 monolayer on epitaxial graphene bilayer in van der Waals p-n junction

Tunable Doping in Hydrogenated Single Layered Molybdenum Disulfide

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In Situ Detection of Active Edge Sites in Single-Layer MoS₂ Catalysts

In Situ Detection of Active Edge Sites in Single-Layer MoS₂ Catalysts