Microsteganography on WS<sub>2</sub> Monolayers Tailored by Direct Laser Painting

Venkatakrishnan, Ashwin; Chua, Hou; Tan, Pinxi; Hu, Zhenliang; Liu, Hongwei; Liu, Yanpeng; Carvalho, Alexandra; Lu, Jinren; Sow, Chorng Haur

doi:10.1021/acsnano.6b07118

Cited by 44 publications

(44 citation statements)

References 32 publications

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“…On the one hand, according to the density functional theory (DFT) calculation results, the interaction between defect sites and gas molecules could renormalize the mid-gap trap states (Fig. 3(c)) [16,50]. On the other hand, the adsorption of gas molecules could lift the screening of excitons, which could stabilize the neutral excitons and defectbound excitons by electron depletion.…”

Section: Defect-bound Exciton Emissionmentioning

confidence: 99%

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How defects influence the photoluminescence of TMDCs

et al. 2020

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Two-dimensional (2D) transition metal dichalcogenide (TMDC) monolayers, a class of ultrathin materials with a direct bandgap and high exciton binding energies, provide an ideal platform to study the photoluminescence (PL) of light-emitting devices. Atomically thin TMDCs usually contain various defects, which enrich the lattice structure and give rise to many intriguing properties. As the influences of defects can be either detrimental or beneficial, a comprehensive understanding of the internal mechanisms underlying defect behaviour is required for PL tailoring. Herein, recent advances in the defect influences on PL emission are summarized and discussed. Fundamental mechanisms are the focus of this review, such as radiative/nonradiative recombination kinetics and band structure modification. Both challenges and opportunities are present in the field of defect manipulation, and the exploration of mechanisms is expected to facilitate the applications of 2D TMDCs in the future.

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Section: Defect-bound Exciton Emissionmentioning

confidence: 99%

“…Defect engineering, such as thermal annealing [17], oxygen plasma bombard (Fig. 5(b)) [17], and laser irradiation [50,75], can make the O atom of the O2/H2O molecules chemically bond to chalcogen vacancies and hence passivate the defect states (shown in Fig. 5(c)) [76].…”

Section: Defect Healingmentioning

confidence: 99%

How defects influence the photoluminescence of TMDCs

et al. 2020

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“…Strong decrease in PL emission has often been found at the oxidized/damaged regions . On the contrary, increase in PL intensity was suggested to occur when oxygen‐related functional groups adsorb on the TMDCs surface . To solve these puzzling PL variation effects, it is necessary to find the relationship between the PL signals and local atomic structures especially taking into account that TMDCs synthesized by chemical vapor deposition (CVD) often show considerable variations in PL intensities even within the single crystal domain.…”

Section: Introductionmentioning

confidence: 99%

Revealing the Atomic Defects of WS₂ Governing Its Distinct Optical Emissions

Lin

Komsa

et al. 2017

Adv Funct Materials

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Defects and their spatial distribution are crucial factors in controlling the electronic and optical properties of semiconductors. By using scanning transmission electron microscopy and electron energy loss spectroscopy, the type of impurities/defects in WS 2 subdomains with different optical properties is successfully assigned. A higher population of Cr impurities is found in the W-terminated edge domain, while the S-terminated domain contains more Fe impurities, in accordance with the luminescence characteristics of chemical-vapor-grown WS 2 of a hexagonal shape. In agreement with the firstprinciples calculations, the domains with Cr substitutional dopants exhibit strong trion emission. Fe atoms tend to gather into trimer configuration and introduce deep acceptor levels which compensate the n-type doping and suppress trion emission. It is also discovered that the domain with higher luminescence but smaller defect concentration tends to get oxidized more rapidly and degrade the 2D structure with many triangular holes. Excitons tend to accumulate at the edges of the oxidized triangular holes and results in enhanced PL emission. The findings indicate that choosing stable elements as dopant and controlling the number of specific edge structures within a crystal domain of 2D transitional metal dichalcogenides can be a new route to improve the optical properties of these materials.

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“…Venkatakrishnan et al . 13 reported a laser thinning of WS 2 flake down to single-layer with revealing improvement of the fluorescence emission intensity and micro-encryption by surface modification. Ni et al .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of uniform single layer WS2 for tunable photoluminescence

Park

Kim

Cha

et al. 2017

Sci Rep

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Two-dimensional transition metal dichalcogenides (2D TMDs) have gained great interest due to their unique tunable bandgap as a function of the number of layers. Especially, single-layer tungsten disulfides (WS2) is a direct band gap semiconductor with a gap of 2.1 eV featuring strong photoluminescence and large exciton binding energy. Although synthesis of MoS2 and their layer dependent properties have been studied rigorously, little attention has been paid to the formation of single-layer WS2 and its layer dependent properties. Here we report the scalable synthesis of uniform single-layer WS2 film by a two-step chemical vapor deposition (CVD) method followed by a laser thinning process. The PL intensity increases six-fold, while the PL peak shifts from 1.92 eV to 1.97 eV during the laser thinning from few-layers to single-layer. We find from the analysis of exciton complexes that both a neutral exciton and a trion increases with decreasing WS2 film thickness; however, the neutral exciton is predominant in single-layer WS2. The binding energies of trion and biexciton for single-layer WS2 are experimentally characterized at 35 meV and 60 meV, respectively. The tunable optical properties by precise control of WS2 layers could empower a great deal of flexibility in designing atomically thin optoelectronic devices.

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Microsteganography on WS₂ Monolayers Tailored by Direct Laser Painting

Cited by 44 publications

References 32 publications

How defects influence the photoluminescence of TMDCs

How defects influence the photoluminescence of TMDCs

Revealing the Atomic Defects of WS₂ Governing Its Distinct Optical Emissions

Synthesis of uniform single layer WS2 for tunable photoluminescence

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Microsteganography on WS2 Monolayers Tailored by Direct Laser Painting

Cited by 44 publications

References 32 publications

How defects influence the photoluminescence of TMDCs

How defects influence the photoluminescence of TMDCs

Revealing the Atomic Defects of WS2 Governing Its Distinct Optical Emissions

Synthesis of uniform single layer WS2 for tunable photoluminescence

Contact Info

Product

Resources

About

Microsteganography on WS₂ Monolayers Tailored by Direct Laser Painting

Revealing the Atomic Defects of WS₂ Governing Its Distinct Optical Emissions