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High Detectivity Graphene‐Silicon Heterojunction Photodetector
Author(s) -
Li Xinming,
Zhu Miao,
Du Mingde,
Lv Zheng,
Zhang Li,
Li Yuanchang,
Yang Yao,
Yang Tingting,
Li Xiao,
Wang Kunlin,
Zhu Hongwei,
Fang Ying
Publication year - 2016
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.201502336
Subject(s) - graphene , photodetector , heterojunction , materials science , responsivity , dark current , optoelectronics , specific detectivity , silicon , oxide , nanotechnology , metallurgy
A graphene/n‐type silicon (n‐Si) heterojunction has been demonstrated to exhibit strong rectifying behavior and high photoresponsivity, which can be utilized for the development of high‐performance photodetectors. However, graphene/n‐Si heterojunction photodetectors reported previously suffer from relatively low specific detectivity due to large dark current. Here, by introducing a thin interfacial oxide layer, the dark current of graphene/n‐Si heterojunction has been reduced by two orders of magnitude at zero bias. At room temperature, the graphene/n‐Si photodetector with interfacial oxide exhibits a specific detectivity up to 5.77 × 10 13 cm Hz 1/2 W ‐1 at the peak wavelength of 890 nm in vacuum, which is highest reported detectivity at room temperature for planar graphene/Si heterojunction photodetectors. In addition, the improved graphene/n‐Si heterojunction photodetectors possess high responsivity of 0.73 A W −1 and high photo‐to‐dark current ratio of ≈10 7 . The current noise spectral density of the graphene/n‐Si photodetector has been characterized under ambient and vacuum conditions, which shows that the dark current can be further suppressed in vacuum. These results demonstrate that graphene/Si heterojunction with interfacial oxide is promising for the development of high detectivity photodetectors.