Atypical Defect-Mediated Photoluminescence and Resonance Raman Spectroscopy of Monolayer WS<sub>2</sub>

Li, Jiake; Su, Weitao; Chen, Fei; Fu, Li; Ding, Su; Song, Kaixin; Huang, Xiwei; Zhang, Lijie

doi:10.1021/acs.jpcc.8b11647

Cited by 50 publications

(48 citation statements)

References 53 publications

(114 reference statements)

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“…A negative bias voltage of −300 V was applied to keep glow discharge for 30 min. WS 2 film was prepared through a CVD method (Figure 1b) [45,46]. The WS 2 powders (Aladdin, Shanghai, China) were loaded in the center of the CVD system and heated to 1000 °C from room temperature over 30 min.…”

Section: Methodsmentioning

confidence: 99%

A Bilayer 2D-WS2/Organic-Based Heterojunction for High-Performance Photodetectors

Huang

et al. 2019

Nanomaterials

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Two-dimensional (2D) tungsten disulfide (WS2) has inspired great efforts in optoelectronics, such as in solar cells, light-emitting diodes, and photodetectors. However, chemical vapor deposition (CVD) grown 2D WS2 domains with the coexistence of a discontinuous single layer and multilayers are still not suitable for the fabrication of photodetectors on a large scale. An emerging field in the integration of organic materials with 2D materials offers the advantages of molecular diversity and flexibility to provide an exciting aspect on high-performance device applications. Herein, we fabricated a photodetector based on a 2D-WS2/organic semiconductor materials (mixture of the (Poly-(N,N′-bis-4-butylphenyl-N,N′-bisphenyl) benzidine and Phenyl-C61-butyric acid methyl ester (Poly-TPD/PCBM)) heterojunction. The application of Poly-TPD/PCBM organic blend film enhanced light absorption, electrically connected the isolated WS2 domains, and promoted the separation of electron-hole pairs. The generated exciton could sufficiently diffuse to the interface of the WS2 and the organic blend layers for efficient charge separation, where Poly-TPD was favorable for hole carrier transport and PCBM for electron transport to their respective electrodes. We show that the photodetector exhibited high responsivity, detectivity, and an on/off ratio of 0.1 A/W, 1.1 × 1011 Jones, and 100, respectively. In addition, the photodetector showed a broad spectral response from 500 nm to 750 nm, with a peak external quantum efficiency (EQE) of 8%. Our work offers a facile solution-coating process combined with a CVD technique to prepare an inorganic/organic heterojunction photodetector with high performance on silicon substrate.

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Section: Methodsmentioning

confidence: 99%

A Bilayer 2D-WS2/Organic-Based Heterojunction for High-Performance Photodetectors

Huang

et al. 2019

Nanomaterials

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“…[ 46,47 ] As the doping concentration increases, the intensity of ZA(M) and LA(M) modes at 109 cm –1 and 128 cm –1 become prominent (Figure 1e) corresponding to the defect‐activated bands of WSe 2 . [ 48–50 ] As Re atoms are introduced, they break translational symmetry in the WSe 2 and increase structural disorder leading to these defect activated modes. [ 36,39,48,50 ] BEOL films exhibit similar Raman spectral trends as a function of Re concentration (Figures S6c and S7c, Supporting Information), with the addition of the A 1g 2 mode at 309 cm –1 indicating multilayer growth that is validated by AFM (Figure S2a–c, Supporting Information).…”

Section: Figurementioning

confidence: 99%

Scalable Substitutional Re‐Doping and its Impact on the Optical and Electronic Properties of Tungsten Diselenide

et al. 2020

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Doping is the cornerstone of semiconductor technology, enabling the success of modern digital electronics. 2D transition metal dichalcogenides (TMDCs) are promising material platforms for future electronics applications where its wafer-scale synthesis and controllable doping will be a required prerequisite to drive the next technological revolution. [1-6] Successful realization of wafer-scale, electronic grade, intrinsic 2D TMDCs via common deposition methods is rapidly progressing, however, advances in scalable doping still remain in the "proof-of-concept" stage, delaying the largescale fabrication of logic circuits based on extrinsic 2D semiconductors. [7-12] Moreover, integration of 2D TMDCs with Si complementary metal-oxide-semiconductor at the back-end-of-line (BEOL) is being actively explored for diffusion barriers, liners, and thin-film-transistors to improve the overall integrated circuit performance. [13-16] However, BEOL production lines are Reliable, controlled doping of 2D transition metal dichalcogenides will enable the realization of next-generation electronic, logic-memory, and magnetic devices based on these materials. However, to date, accurate control over dopant concentration and scalability of the process remains a challenge. Here, a systematic study of scalable in situ doping of fully coalesced 2D WSe 2 films with Re atoms via metal-organic chemical vapor deposition is reported. Dopant concentrations are uniformly distributed over the substrate surface, with precisely controlled concentrations down to <0.001% Re achieved by tuning the precursor partial pressure. Moreover, the impact of doping on morphological, chemical, optical, and electronic properties of WSe 2 is elucidated with detailed experimental and theoretical examinations, confirming that the substitutional doping of Re at the W site leads to n-type behavior of WSe 2. Transport characteristics of fabricated back-gated fieldeffect-transistors are directly correlated to the dopant concentration, with degrading device performances for doping concentrations exceeding 1% of Re. The study demonstrates a viable approach to introducing true dopantlevel impurities with high precision, which can be scaled up to batch production for applications beyond digital electronics.

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“…Most importantly, the B 2g 1 phonon (~310 cm −1 ) peak has been reported to correspond to layer-layer interaction, which is active for multilayers but inactive for monolayers 23 . Figure 2d shows that the B 2g 1 phonon peak did not appear in the exfoliated highquality WS 2 thin sheets, indicating that they are monolayer in structure [23][24][25][26][27] . These results validate the successful large-scale production of monolayer WS 2 thin sheets having a relatively high crystallinity.…”

Section: Stability Of Ws 2 Thin Sheet Suspensionmentioning

confidence: 99%

Synthesis of high-quality monolayer tungsten disulfide with chlorophylls and its application for enhancing bone regeneration

et al. 2020

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Due to the population explosion of the 21st century, nearly one billion people are over 64 years of age and bone fracture is one of the most frequent problems facing both sexes because of osteoporosis. However, difficulty in enhancing bone regeneration to repair bone fracture poses challenges and thus, a two-dimensional monolayer material (i.e. tungsten disulfide (WS2)) could be one of the candidates offering a possible solution to the problem. Here, we prepare high-quality monolayer WS2 thin sheets in a large quantity with the assistance of extracted chlorophyll molecules, the natural pigment used in photosynthesis, via a liquid-phase exfoliation method. Then, the exfoliated WS2 sheets were mixed with polycaprolactone (PCL)/calcium silicate (CS) to form a biocompatible WS2-based composite. The in vivo experiments show that the bone regeneration of the WS2-based composite was 120% superior to commercially available mineral trioxide aggregate (MTA) bone cement. Moreover, the mechanical properties of the WS2-based composite exhibited ~300% enhancement over PCL/CS, which is one of the most commonly used bone regeneration materials. Our findings highlight the prospects for the composite of WS2 towards the improvement of bone regeneration applications.

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Atypical Defect-Mediated Photoluminescence and Resonance Raman Spectroscopy of Monolayer WS₂

Cited by 50 publications

References 53 publications

A Bilayer 2D-WS2/Organic-Based Heterojunction for High-Performance Photodetectors

A Bilayer 2D-WS2/Organic-Based Heterojunction for High-Performance Photodetectors

Scalable Substitutional Re‐Doping and its Impact on the Optical and Electronic Properties of Tungsten Diselenide

Synthesis of high-quality monolayer tungsten disulfide with chlorophylls and its application for enhancing bone regeneration

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Atypical Defect-Mediated Photoluminescence and Resonance Raman Spectroscopy of Monolayer WS2

Cited by 50 publications

References 53 publications

A Bilayer 2D-WS2/Organic-Based Heterojunction for High-Performance Photodetectors

A Bilayer 2D-WS2/Organic-Based Heterojunction for High-Performance Photodetectors

Scalable Substitutional Re‐Doping and its Impact on the Optical and Electronic Properties of Tungsten Diselenide

Synthesis of high-quality monolayer tungsten disulfide with chlorophylls and its application for enhancing bone regeneration

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Atypical Defect-Mediated Photoluminescence and Resonance Raman Spectroscopy of Monolayer WS₂