Ferroelectric Localized Field–Enhanced ZnO Nanosheet Ultraviolet Photodetector with High Sensitivity and Low Dark Current |
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| Authors: | Peng Wang Yang Wang Lei Ye Mingzai Wu Runzhang Xie Xudong Wang Xiaoshuang Chen Zhiyong Fan Jianlu Wang Weida Hu |
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| Affiliation: | 1. School of Physics and Materials Science, Anhui University, Hefei, China;2. State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, China;3. School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei, China;4. Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China SAR |
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| Abstract: | Zinc oxide (ZnO) nanosheets have demonstrated outstanding electrical and optical properties, which are well suited for ultraviolet (UV) photodetectors. However, they have a high density of intrinsically unfilled traps, and it is difficult to achieve p‐type doping, leading to the poor performance for low light level switching ratio and a high dark current that limit practical applications in UV photodetection. Here, UV photodetectors based on ZnO nanosheets are demonstrated, whose performance is significantly improved by using a ferroelectric localized field. Specifically, the photodetectors have achieved a responsivity of up to 3.8 × 105 A W?1, a detectivity of 4.4 × 1015 Jones, and a photocurrent gain up to 1.24 × 106. These device figures of merit are far beyond those of traditional ZnO ultraviolet photodetectors. In addition, the devices' initial dark current can be easily restored after continuous photocurrent measurement by using a positive gate voltage pulse. This study establishes a new approach to produce high‐sensitivity and low‐dark‐current ultraviolet photodetectors and presents a crucial step for further practical applications. |
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| Keywords: | dark current detectivity ferroelectric localized field ultraviolet photodetectors zinc oxide nanosheet |
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