Highly active single-layer MoS<sub>2</sub> catalysts synthesized by swift heavy ion irradiation

Madauß, Lukas; Zegkinoglou, Ioannis; Muíños, Henrique Vázquez; Choi, Young‐Ae; Kunze, Sebastian; Zhao, Meng‐Qiang; Naylor, Carl H.; Ernst, Philipp; Pollmann, Erik; Ochedowski, Oliver; Lebius, H.; Benyagoub, A.; Ban-d’Etat, B.; Johnson, A. T. Charlie; Djurabekova, Flyura; Cuenya, Beatriz Roldán; Schleberger, Marika

doi:10.1039/c8nr04696d

Cited by 49 publications

(52 citation statements)

References 58 publications

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“…More recently, the catalytic properties of such SHI irradiated Mo2

single layers have been addressed in more detail. Madauss et al analyzed the irradiated samples by means of AFM, SEM, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements and complemented their study by theoretical simulations based on the TTM [ 137 ]. From the data, it was deduced that the irradiation with SHI not only produces nano-incisions with molybdenum-rich edges but that sulfur is removed from the basal planes as well due to the thermal spike in the underlying substrate.…”

Section: Defect Engineering By Particle Irradiation: State Of the mentioning

confidence: 99%

2D Material Science: Defect Engineering by Particle Irradiation

Schleberger

Kotakoski

2018

Materials

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Two-dimensional (2D) materials are at the heart of many novel devices due to their unique and often superior properties. For simplicity, 2D materials are often assumed to exist in their text-book form, i.e., as an ideal solid with no imperfections. However, defects are ubiquitous in macroscopic samples and play an important – if not imperative – role for the performance of any device. Thus, many independent studies have targeted the artificial introduction of defects into 2D materials by particle irradiation. In our view it would be beneficial to develop general defect engineering strategies for 2D materials based on a thorough understanding of the defect creation mechanisms, which may significantly vary from the ones relevant for 3D materials. This paper reviews the state-of-the-art in defect engineering of 2D materials by electron and ion irradiation with a clear focus on defect creation on the atomic scale and by individual impacts. Whenever possible we compile reported experimental data alongside corresponding theoretical studies. We show that, on the one hand, defect engineering by particle irradiation covers a wide range of defect types that can be fabricated with great precision in the most commonly investigated 2D materials. On the other hand, gaining a complete understanding still remains a challenge, that can be met by combining advanced theoretical methods and improved experimental set-ups, both of which only now begin to emerge. In conjunction with novel 2D materials, this challenge promises attractive future opportunities for researchers in this field.

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“…More recently, the catalytic properties of such SHI irradiated Mo2

Section: Defect Engineering By Particle Irradiation: State Of the mentioning

confidence: 99%

2D Material Science: Defect Engineering by Particle Irradiation

Schleberger

Kotakoski

2018

Materials

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“…The exposure to low-energy electrons and/or ions can modify the electronic properties of the 2D materials or their interfaces. 9 , 17 , 26 Indeed, structural defects can locally modify the band structure and behave as charge traps, thereby changing the device characteristics both in the case of e-beam 27 , 28 and ion beam irradiation. 29 , 30 Conversely, electron beam, ion irradiation, or plasma treatments can be intentionally used for nanoincisions, 31 for pores, 32 or to purposely create defects, for instance, to reduce the contact resistance.…”

Section: Introductionmentioning

confidence: 99%

Electron Irradiation of Metal Contacts in Monolayer MoS₂ Field-Effect Transistors

Pelella

Kharsah

Grillo

et al. 2020

ACS Appl. Mater. Interfaces

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Metal contacts play a fundamental role in nanoscale devices. In this work, Schottky metal contacts in monolayer molybdenum disulfide (MoS 2 ) field-effect transistors are investigated under electron beam irradiation. It is shown that the exposure of Ti/Au source/drain electrodes to an electron beam reduces the contact resistance and improves the transistor performance. The electron beam conditioning of contacts is permanent, while the irradiation of the channel can produce transient effects. It is demonstrated that irradiation lowers the Schottky barrier at the contacts because of thermally induced atom diffusion and interfacial reactions. The simulation of electron paths in the device reveals that most of the beam energy is absorbed in the metal contacts. The study demonstrates that electron beam irradiation can be effectively used for contact improvement through local annealing.

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“…While both first‐order phonon modes

E_{2 g}^{1}

and A 1g can clearly be identified for all (pristine and patterned) samples, we observe a decrease in Raman intensity with the increase of fluence, indicating an increase in the number of defects such as chalcogen (here sulfur) vacancies induced by the ion beam, [ 38,41 ] and/or amorphization of edges in patterned‐MLs. [ 33,44 ] Furthermore, the positions of the two Raman peaks as well as their separation (

Δ = pos (A_{1 g}) - pos (E_{2 g}^{1})

) are summarized in Figure 3b,c, respectively, as a function of fluence. While a slight blueshift of both first‐order phonon modes

E_{2 g}^{1}

and A 1g can be seen with the increase in the ion fluence, the variation of their spectral separation is negligible and does not follow any trend as a function of fluence.…”

Section: Resultsmentioning

confidence: 99%

“…The remaining TMD-ML material suffers partial damage, in particular close to their edges, due to the impact of stray ions from the etching process. [33,44] Considering the ever-increasing importance of patterned TMD-MLs, it is highly desirable to realize a simple nanopatterning method and at the same time understand how nanopatterning influences the optical characteristics of TMD-MLs.…”

Section: Nanopatterning Of Monolayers Of Transition Metal Dichalcogenmentioning

confidence: 99%

Facile Resist‐Free Nanopatterning of Monolayers of MoS₂ by Focused Ion‐Beam Milling

Mupparapu

Steinert

George

et al. 2020

Adv Materials Inter

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Nanopatterning of monolayers of transition metal dichalcogenides offers a new avenue for the creation of nanoscale light sources and their integration into hybrid nanophotonic systems. Here, focused gallium ion‐beam milling is employed as a resist‐free and simple nanofabrication approach to pattern MoS2 monolayers grown by chemical vapor deposition into nanoribbons. Using photoluminescence (PL), Raman, and valley polarization spectroscopy, it is investigated how the optoelectronic properties of the MoS2 monolayers are affected by the nanopatterning as a function of the ion fluence used for milling. Characteristic spectral shifts in the Raman and PL peaks are observed, which are indicative of a release of strain in patterned MoS2 monolayers as compared to the as‐grown monolayers. Furthermore, while the total PL signal is reduced in the patterned monolayers, using circular‐polarization‐resolved cryogenic PL spectroscopy it is shown that the valley polarization is well preserved for monolayers patterned within an optimal ion‐fluence range. The results and in particular the observed robustness of the valley polarization indicate that focused ion‐beam nanopatterned MoS2 monolayers are interesting candidates for their integration into hybrid quantum systems consisting of designed photonic nanostructures and precisely placed nanoscale excitonic light sources.

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Highly active single-layer MoS₂ catalysts synthesized by swift heavy ion irradiation

Abstract: Swift heavy ion irradiation as a precise tool for nanostructuring materials allows the modification of ultrathin two-dimensional MoS2 such that the number of catalytically active edges is drastically increased, leading to a strongly enhanced performance in the hydrogen evolution reaction.

Cited by 49 publications

References 58 publications

2D Material Science: Defect Engineering by Particle Irradiation

2D Material Science: Defect Engineering by Particle Irradiation

Electron Irradiation of Metal Contacts in Monolayer MoS₂ Field-Effect Transistors

Facile Resist‐Free Nanopatterning of Monolayers of MoS₂ by Focused Ion‐Beam Milling

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Highly active single-layer MoS2 catalysts synthesized by swift heavy ion irradiation

Abstract: Swift heavy ion irradiation as a precise tool for nanostructuring materials allows the modification of ultrathin two-dimensional MoS2 such that the number of catalytically active edges is drastically increased, leading to a strongly enhanced performance in the hydrogen evolution reaction.

Cited by 49 publications

References 58 publications

2D Material Science: Defect Engineering by Particle Irradiation

2D Material Science: Defect Engineering by Particle Irradiation

Electron Irradiation of Metal Contacts in Monolayer MoS2 Field-Effect Transistors

Facile Resist‐Free Nanopatterning of Monolayers of MoS2 by Focused Ion‐Beam Milling

Contact Info

Product

Resources

About

Highly active single-layer MoS₂ catalysts synthesized by swift heavy ion irradiation

Electron Irradiation of Metal Contacts in Monolayer MoS₂ Field-Effect Transistors

Facile Resist‐Free Nanopatterning of Monolayers of MoS₂ by Focused Ion‐Beam Milling