Photoluminescence quenching of CVD grown WS2 monolayers treated with low-power Ar plasma

Barbosa, André do Nascimento; Mendoza, Cesar D.; Lei, Yu; Giarola, Marco; Terrones, Mauricio; Mariotto, G.; Freire, F.L.

doi:10.1016/j.surfin.2022.102220

Cited by 12 publications

(14 citation statements)

References 40 publications

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“…2a 32,[39][40][41] . The firstand second-order longitudinal acoustic modes, LA(M) and 2LA(M), seen here at 175 cm −1 and 349 cm −1 , respectably, are identified as key markers for examining the prevalence of defects within ML WS 2 [42][43][44] . The 2LA(M) mode is deconvolved from a broad peak situated around 355 cm −1 using multi-peak fitting, which also reveals a second sub-peak at 357 cm −1 identified as the in-plane vibrations of tungsten and sulphur atoms ðE 1 2g ðΓÞÞ 32,39-41 .…”

Section: Steady-state Photoluminescence and Raman Spectroscopy Of Fib...mentioning

confidence: 75%

“…2f. Like PL intensities, the Raman peak intensity of 2LA(M) is suppressed around the milled area, further highlighting the increasing density of defects [42][43][44] . Furthermore, analysing the LA(M) mode in the Pristine, the "far-out" zone (@ 200 μm), and the "near" zone (@ 5μm), as shown in Fig.…”

Section: Steady-state Photoluminescence and Raman Spectroscopy Of Fib...mentioning

confidence: 94%

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Understanding the impact of heavy ions and tailoring the optical properties of large-area monolayer WS2 using focused ion beam

et al. 2023

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Focused ion beam (FIB) is an effective tool for precise nanoscale fabrication. It has recently been employed to tailor defect engineering in functional nanomaterials such as two-dimensional transition metal dichalcogenides (TMDCs), providing desirable properties in TMDC-based optoelectronic devices. However, the damage caused by the FIB irradiation and milling process to these delicate, atomically thin materials, especially in extended areas beyond the FIB target, has not yet been fully characterised. Understanding the correlation between lateral ion beam effects and optical properties of 2D TMDCs is crucial in designing and fabricating high-performance optoelectronic devices. In this work, we investigate lateral damage in large-area monolayer WS2 caused by the gallium focused ion beam milling process. Three distinct zones away from the milling location are identified and characterised via steady-state photoluminescence (PL) and Raman spectroscopy. The emission in these three zones have different wavelengths and decay lifetimes. An unexpected bright ring-shaped emission around the milled location has also been revealed by time-resolved PL spectroscopy with high spatial resolution. Our findings open up new avenues for tailoring the optical properties of TMDCs by charge and defect engineering via focused ion beam lithography. Furthermore, our study provides evidence that while some localised damage is inevitable, distant destruction can be eliminated by reducing the ion beam current. It paves the way for the use of FIB to create nanostructures in 2D TMDCs, as well as the design and realisation of optoelectrical devices on a wafer scale.

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Section: Steady-state Photoluminescence and Raman Spectroscopy Of Fib...mentioning

confidence: 75%

Section: Steady-state Photoluminescence and Raman Spectroscopy Of Fib...mentioning

confidence: 94%

Understanding the impact of heavy ions and tailoring the optical properties of large-area monolayer WS2 using focused ion beam

et al. 2023

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“…The quenching and redshift of the PL emission indicate a modulation in the band structure caused either by the formation of defects, substitutional doping, or both. 49 This trend was also observed in WSe 2 and MoS 2 (Supporting Information Figure S1). The PL emission peaks shown in Figure 1f and g are asymmetric, indicating the presence of more than one peak, which is revealed through Lorentzian line shape peak fitting.…”

Section: Resultsmentioning

confidence: 99%

“…After patterning, there is a marked decrease in the PL emission intensity by approximately 36% and a slight redshift in the spectral weight of the emission peak. The quenching and redshift of the PL emission indicate a modulation in the band structure caused either by the formation of defects, substitutional doping, or both . This trend was also observed in WSe 2 and MoS 2 (Supporting Information Figure S1).…”

Section: Results and Discussionmentioning

confidence: 99%

Precision Modification of Monolayer Transition Metal Dichalcogenides via Environmental E-Beam Patterning

Selhorst

Moore

et al. 2023

ACS Nano

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Layered Transition Metal Dichalcogenides (TMDs) are an important class of materials that exhibit a wide variety of optoelectronic properties. The ability to spatially tailor their expansive property-space (e.g., conduction behavior, optical emission, surface interactions) is of special interest for applications including, but not limited to, sensing, bioelectronics, and spintronics/valleytronics. Current methods of property modulation focus on the modification of the basal surfaces and edge sites of the TMDs by the introduction of defects, functionalization with organic or inorganic moieties, alloying, heterostructure formation, and phase engineering. A majority of these methods lack the resolution for the development of next-generation nanoscale devices or are limited in the types of functionalities useful for efficient TMD property modification. In this study, we utilize electron-beam patterning on monolayer TMDs (MoSe2, WSe2 and MoS2) in the presence of a pressure-controlled atmosphere of water vapor within an environmental scanning electron microscope (ESEM). A series of parametric studies show local optical and electronic property modification depending on acceleration voltage, beam current, pressure, and electron dose. The ultimate pattern resolution achieved is 67 ± 9 nm. Raman and photoluminescence spectroscopies coupled with Kelvin Probe Force Microscopy reveal electron dose-dependent p-doping in the patterned regions, which we attribute to functionalization from the products of water vapor radiolysis (oxygen and hydroxyl groups). The modulation of the work function through patterning matches well with Density Functional Theory modeling. Finally, post-functionalization of the patterned areas with an organic fluorophore demonstrates a robust method to achieve nanoscale functionalization with high fidelity.

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“…Slow energy argon (Ar) plasma treatment has been used as a nondestructive preconditioning technique to tailor the electrical and optical properties of TMDs. 41,42 On the other hand, mild Ar plasma is also oen employed to controllably introduce vacancy in 2D system, for example, preferentially sputtering Se in 2D PtSe 2 . 43,44 To this regard, we introduce different amounts of Se vacancies in InSe by changing Ar plasma treatment duration and show the corresponding Raman spectra of InSe in Fig.…”

Section: The Effect Of Vacancy Density On the Evolution Of Plmentioning

confidence: 99%

Revealing the origin of PL evolution of InSe flake induced by laser irradiation

et al. 2023

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Photoluminescence quenching of CVD grown WS2 monolayers treated with low-power Ar plasma

Cited by 12 publications

References 40 publications

Understanding the impact of heavy ions and tailoring the optical properties of large-area monolayer WS2 using focused ion beam

Understanding the impact of heavy ions and tailoring the optical properties of large-area monolayer WS2 using focused ion beam

Precision Modification of Monolayer Transition Metal Dichalcogenides via Environmental E-Beam Patterning

Revealing the origin of PL evolution of InSe flake induced by laser irradiation

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