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Xu H, Zhu J, Zou G, Liu W, Li X, Li C, Ryu GH, Xu W, Han X, Guo Z, Warner JH, Wu J, Liu H. Spatially Bandgap-Graded MoS 2(1-x)Se 2x Homojunctions for Self-Powered Visible-Near-Infrared Phototransistors. Nanomicro Lett 2020; 12:26. [PMID: 34138072 PMCID: PMC7770748 DOI: 10.1007/s40820-019-0361-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/10/2019] [Indexed: 05/26/2023]
Abstract
Ternary transition metal dichalcogenide alloys with spatially graded bandgaps are an emerging class of two-dimensional materials with unique features, which opens up new potential for device applications. Here, visible-near-infrared and self-powered phototransistors based on spatially bandgap-graded MoS2(1-x)Se2x alloys, synthesized by a simple and controllable chemical solution deposition method, are reported. The graded bandgaps, arising from the spatial grading of Se composition and thickness within a single domain, are tuned from 1.83 to 1.73 eV, leading to the formation of a homojunction with a built-in electric field. Consequently, a strong and sensitive gate-modulated photovoltaic effect is demonstrated, enabling the homojunction phototransistors at zero bias to deliver a photoresponsivity of 311 mA W-1, a specific detectivity up to ~ 1011 Jones, and an on/off ratio up to ~ 104. Remarkably, when illuminated by the lights ranging from 405 to 808 nm, the biased devices yield a champion photoresponsivity of 191.5 A W-1, a specific detectivity up to ~ 1012 Jones, a photoconductive gain of 106-107, and a photoresponsive time in the order of ~ 50 ms. These results provide a simple and competitive solution to the bandgap engineering of two-dimensional materials for device applications without the need for p-n junctions.
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Affiliation(s)
- Hao Xu
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
| | - Juntong Zhu
- School of Energy, Soochow Institute for Energy and Materials Innovations, and Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou, 215006, People's Republic of China
| | - Guifu Zou
- School of Energy, Soochow Institute for Energy and Materials Innovations, and Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou, 215006, People's Republic of China.
| | - Wei Liu
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
- London Centre for Nanotechnology, University College London, London, WC1H 0AH, UK
| | - Xiao Li
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
| | - Caihong Li
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China
| | - Gyeong Hee Ryu
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
| | - Wenshuo Xu
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
| | - Xiaoyu Han
- Department of Chemistry, University College London, 20 Gordon St, Bloomsbury, London, WC1H 0AJ, UK
| | - Zhengxiao Guo
- Department of Chemistry, University College London, 20 Gordon St, Bloomsbury, London, WC1H 0AJ, UK
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, People's Republic of China
- Zhejiang Institute of Research and Innovation, The University of Hong Kong, Qingshan Lake SciTech City, Hangzhou, People's Republic of China
| | - Jamie H Warner
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
| | - Jiang Wu
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, People's Republic of China.
| | - Huiyun Liu
- Department of Electronic and Electrical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK
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