Quick Optical Identification of the Defect Formation in Monolayer WSe2 for Growth Optimization

Long, Fang; Chen, Haitao; Yuan, Xiaoming; Huang, Han; Chen, Gen; Li, Lin; Ding, Junnan; He, Jun; Tao, Shaohua

doi:10.1186/s11671-019-3110-z

Cited by 28 publications

(20 citation statements)

References 65 publications

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“…Considering that defects could decompose TMDs (Fang et al, 2019;Gao et al, 2016), we confirmed the stability of our multi-domain WS 2 monolayer. The confocal Raman and PL and optical microscope images S4 show that the sample is stable over two years without significant decomposition.…”

Section: Resultssupporting

confidence: 76%

Bandgap modulation in the two-dimensional core-shell-structured monolayers of WS2

et al. 2022

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Tungsten disulfide (WS 2 ) has tunable bandgaps, which are required for diverse optoelectronic device applications. Here, we report the bandgap modulation in WS 2 monolayers with two-dimensional core-shell structures formed by unique growth mode in chemical vapor deposition (CVD). The core-shell structures in our CVD-grown WS 2 monolayers exhibit contrasts in optical images, Raman, and photoluminescence spectroscopy. The strain and doping effects in the WS 2 , introduced by two different growth processes, generate PL peaks at 1.83 eV (at the core domain) and 1.98 eV (at the shell domain), which is distinct from conventional WS 2 with a primary PL peak at 2.02 eV. Our density functional theory (DFT) calculations explain the modulation of the optical bandgap in our coreshell-structured WS 2 monolayers by the strain, accompanying a direct-to-indirect bandgap transition. Thus, the core-shell-structured WS 2 monolayers provide a practical method to fabricate lateral heterostructures with different optical bandgaps, which are required for optoelectronic applications.

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Section: Resultssupporting

confidence: 76%

Bandgap modulation in the two-dimensional core-shell-structured monolayers of WS2

et al. 2022

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“…The full-width half maxima (FWHM) of BP were measured to be 93 meV and that of MoS 2 is 252 meV, which is about 2.7 times higher than that of the BP layer. The lower FWHM of BP compared to that of the MoS 2 is likely to arise from the more tightly bound atoms in BP's puckered structure compared to MoS 2 and the presence of a higher defect density in the latter, compared to BP [42].…”

Section: Resultsmentioning

confidence: 99%

Black Phosphorus-Molybdenum Disulfide Hetero-Junctions Formed with Ink-Jet Printing for Potential Solar Cell Applications with Indium-Tin-Oxide

Mehta

Kaul

2021

Crystals

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In this work, we implemented liquid exfoliation to inkjet-print two-dimensional (2D) black phosphorous (BP) and molybdenum disulfide (MoS2) p–n heterojunctions on a standard indium tin oxide (ITO) glass substrate in a vertical architecture. We also compared the optical and electrical properties of the inkjet-printed BP layer with that of the MoS2 and the electrical properties of the mechanically exfoliated MoS2 with that of the inkjet-printed MoS2. We found significant differences in the optical characteristics of the inkjet-printed BP and MoS2 layers attributed to the differences in their underlying crystal structure. The newly demonstrated liquid exfoliated and inkjet-printed BP–MoS2 2D p–n junction was also compared with previous reports where mechanically exfoliated BP–MoS2 2D p–n junction were used. The electronic transport properties of mechanically exfoliated MoS2 membranes are typically better compared to inkjet-printed structures but inkjet printing offers a cost-effective and quicker way to fabricate heterostructures easily. In the future, the performance of inkjet-printed structures can be further improved by employing suitable contact materials, amongst other factors such as modifying the solvent chemistries. The architecture reported in this work has potential applications towards building solar cells with solution processed 2D materials in the future.

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“…Overall, the relationship among the peak intensities of the free (X 0 ), charged (X ‐ ), and bound (X B ) exciton emissions (note that these peaks are located at different energies) can be an indicator of the defect density in monolayer TMDCs. [ 117 , 118 ] In general, a lower intensity for the neutral emission and a higher intensity for the emission of the charged or bound exciton corresponds to a higher number of defects; [ 119 , 120 ] this correlation has been applied to monitor structural quality during optimization of the growth of monolayer TMDCs (Figure 3d ). [ 120 ]…”

Section: Identifying Defects In 2d Materialsmentioning

confidence: 99%

“…[ 117 , 118 ] In general, a lower intensity for the neutral emission and a higher intensity for the emission of the charged or bound exciton corresponds to a higher number of defects; [ 119 , 120 ] this correlation has been applied to monitor structural quality during optimization of the growth of monolayer TMDCs (Figure 3d ). [ 120 ]…”

Section: Identifying Defects In 2d Materialsmentioning

confidence: 99%

“…Briefly, for h‐BN‐encapsulated graphene and BP, [ 220 , 223 ] the narrower FWHMs of their characteristic Raman peaks suggested superior quality; [ 106 ] the narrower FWHMs of the excitonic PL peaks of TMDCs [ 222 ] meant that h‐BN could effectively suppress fluctuations and the introduction of defects arising from the SiO 2 surface; [ 121 ] and the enhanced PL intensities and lower PL decay rates of encapsulated InSe and GaSe [ 221 ] demonstrated their high quality and long‐term stability. [ 120 ]…”

Section: Optical Inspection Of Vdw Integration Of 2d Materialsmentioning

confidence: 99%

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Optical Inspection of 2D Materials: From Mechanical Exfoliation to Wafer‐Scale Growth and Beyond

et al. 2021

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Optical inspection is a rapid and non-destructive method for characterizing the properties of two-dimensional (2D) materials. With the aid of optical inspection, in situ and scalable monitoring of the properties of 2D materials can be implemented industrially to advance the development and progress of 2D material-based devices toward mass production. This review discusses the optical inspection techniques that are available to characterize various 2D materials, including graphene, transition metal dichalcogenides (TMDCs), hexagonal boron nitride (h-BN), group-III monochalcogenides, black phosphorus (BP), and group-IV monochalcogenides. First, the authors provide an introduction to these 2D materials and the processes commonly used for their fabrication. Then they review several of the important structural properties of 2D materials, and discuss how to characterize them using appropriate optical inspection tools. The authors also describe the challenges and opportunities faced when applying optical inspection to recently developed 2D materials, from mechanically exfoliated to wafer-scale-grown 2D materials. Most importantly, the authors summarize the techniques available for largely and precisely enhancing the optical signals from 2D materials. This comprehensive review of the current status and perspective of future trends for optical inspection of the structural properties of 2D materials will facilitate the development of next-generation 2D material-based devices.

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Quick Optical Identification of the Defect Formation in Monolayer WSe2 for Growth Optimization

Cited by 28 publications

References 65 publications

Bandgap modulation in the two-dimensional core-shell-structured monolayers of WS2

Bandgap modulation in the two-dimensional core-shell-structured monolayers of WS2

Black Phosphorus-Molybdenum Disulfide Hetero-Junctions Formed with Ink-Jet Printing for Potential Solar Cell Applications with Indium-Tin-Oxide

Optical Inspection of 2D Materials: From Mechanical Exfoliation to Wafer‐Scale Growth and Beyond

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