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Ferroelectric Localized Field–Enhanced ZnO Nanosheet Ultraviolet Photodetector with High Sensitivity and Low Dark Current
Author(s) -
Wang Peng,
Wang Yang,
Ye Lei,
Wu Mingzai,
Xie Runzhang,
Wang Xudong,
Chen Xiaoshuang,
Fan Zhiyong,
Wang Jianlu,
Hu Weida
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201800492
Subject(s) - photodetector , dark current , responsivity , photocurrent , photodetection , optoelectronics , materials science , ultraviolet , nanosheet , doping , photoconductivity , nanotechnology
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 × 10 5 A W −1 , a detectivity of 4.4 × 10 15 Jones, and a photocurrent gain up to 1.24 × 10 6 . 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.