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Nano Research 2018, 11(6): 3371-3384 https://doi.org/10.1007/s12274-017-1941-4
Research Article | Issue | Published: 22 May 2018

Wafer-scale synthesis of monolayer WS2 for high-performance flexible photodetectors by enhanced chemical vapor deposition

Show Author's Information Changyong Lan1,2,  Ziyao Zhou1,3,  Zhifei Zhou2,  Chun Li2,  Lei Shu1,3,  Lifan Shen3,4,  Dapan Li1,3,  Ruoting Dong1,  SenPo Yip1,3,4,  Johnny C. Ho1,3,4,5( )
Department of Materials Science and EngineeringCity University of Hong KongHong Kong999077China
School of Optoelectronic InformationUniversity of Electronic Science and Technology of ChinaChengdu610054China
Shenzhen Research InstituteCity University of Hong KongShenzhen518057China
State Key Laboratory of Millimeter WavesCity University of Hong KongKowloonHong Kong999077China
Centre for Functional PhotonicsCity University of Hong KongKowloonHong Kong999077China
Keywords:
chemical vapor deposition, monolayer, flexible optoelectronics, WS2, wafer-scale
Cite this article:
Lan C, Zhou Z, Zhou Z, et al. Wafer-scale synthesis of monolayer WS2 for high-performance flexible photodetectors by enhanced chemical vapor deposition. Nano Research, 2018, 11(6): 3371-3384. https://doi.org/10.1007/s12274-017-1941-4
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Abstract Full text Electronic supplementary material About this article

Two-dimensional (2D) nanomaterials have recently attracted considerable attention due to their promising applications in next-generation electronics and optoelectronics. In particular, the large-scale synthesis of high-quality 2D materials is an essential requirement for their practical applications. Herein, we demonstrate the wafer-scale synthesis of highly crystalline and homogeneous monolayer WS2 by an enhanced chemical vapor deposition (CVD) approach, in which precise control of the precursor vapor pressure can be effectively achieved in a multi-temperature zone horizontal furnace. In contrast to conventional synthesis methods, the obtained monolayer WS2 has excellent uniformity both in terms of crystallinity and morphology across the entire substrate wafer grown (e.g., 2 inches in diameter), as corroborated by the detailed characterization. When incorporated in typical rigid photodetectors, the monolayer WS2 leads to a respectable photodetection performance, with a responsivity of 0.52 mA/W, a detectivity of 4.9 × 109 Jones, and a fast response speed (< 560 μs). Moreover, once fabricated as flexible photodetectors on polyimide, the monolayer WS2 leads to a responsivity of up to 5 mA/W. Importantly, the photocurrent maintains 89% of its initial value even after 3, 000 bending cycles. These results highlight the versatility of the present technique, which allows its applications in larger substrates, as well as the excellent mechanical flexibility and robustness of the CVD-grown, homogenous WS2 monolayers, which can promote the development of advanced flexible optoelectronic devices.


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Electronic supplementary material
About this article

Wafer-scale synthesis of monolayer WS2 for high-performance flexible photodetectors by enhanced chemical vapor deposition

Show Author's information Changyong Lan1,2, Ziyao Zhou1,3, Zhifei Zhou2, Chun Li2, Lei Shu1,3, Lifan Shen3,4, Dapan Li1,3, Ruoting Dong1, SenPo Yip1,3,4, Johnny C. Ho1,3,4,5( )
Department of Materials Science and EngineeringCity University of Hong KongHong Kong999077China
School of Optoelectronic InformationUniversity of Electronic Science and Technology of ChinaChengdu610054China
Shenzhen Research InstituteCity University of Hong KongShenzhen518057China
State Key Laboratory of Millimeter WavesCity University of Hong KongKowloonHong Kong999077China
Centre for Functional PhotonicsCity University of Hong KongKowloonHong Kong999077China

Abstract

Two-dimensional (2D) nanomaterials have recently attracted considerable attention due to their promising applications in next-generation electronics and optoelectronics. In particular, the large-scale synthesis of high-quality 2D materials is an essential requirement for their practical applications. Herein, we demonstrate the wafer-scale synthesis of highly crystalline and homogeneous monolayer WS2 by an enhanced chemical vapor deposition (CVD) approach, in which precise control of the precursor vapor pressure can be effectively achieved in a multi-temperature zone horizontal furnace. In contrast to conventional synthesis methods, the obtained monolayer WS2 has excellent uniformity both in terms of crystallinity and morphology across the entire substrate wafer grown (e.g., 2 inches in diameter), as corroborated by the detailed characterization. When incorporated in typical rigid photodetectors, the monolayer WS2 leads to a respectable photodetection performance, with a responsivity of 0.52 mA/W, a detectivity of 4.9 × 109 Jones, and a fast response speed (< 560 μs). Moreover, once fabricated as flexible photodetectors on polyimide, the monolayer WS2 leads to a responsivity of up to 5 mA/W. Importantly, the photocurrent maintains 89% of its initial value even after 3, 000 bending cycles. These results highlight the versatility of the present technique, which allows its applications in larger substrates, as well as the excellent mechanical flexibility and robustness of the CVD-grown, homogenous WS2 monolayers, which can promote the development of advanced flexible optoelectronic devices.

Keywords: chemical vapor deposition, monolayer, flexible optoelectronics, WS2, wafer-scale

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Publication history
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Acknowledgements

Publication history

Received: 22 October 2017
Revised: 23 November 2017
Accepted: 29 November 2017
Published: 22 May 2018
Issue date: June 2018

Copyright

© Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2017

Acknowledgements

Acknowledgements

We acknowledge the General Research Fund of the Research Grants Council of Hong Kong SAR, China (CityU 11275916), the National Natural Science Foundation of China (Nos. 51672229, 61605024 and 61522403), the Science Technology and Innovation Committee of Shenzhen Municipality (No. JCYJ20160229165240684) and a grant from the Shenzhen Research Institute, City University of Hong Kong.

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