title: High Detectivity Graphene-Silicon Heterojunction Photodetector.
abstract: 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.
authors.affiliation: National Center for Nanoscience and Technology, Zhongguancun, Beijing, 100190, P. R. China.
authors.forename: Xinming
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China.
authors.forename: Miao
authors.initials: M
authors.lastname: Zhu
authors.affiliation: National Center for Nanoscience and Technology, Zhongguancun, Beijing, 100190, P. R. China.
authors.forename: Mingde
authors.initials: M
authors.lastname: Du
authors.affiliation: Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P. R. China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Lv
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: National Center for Nanoscience and Technology, Zhongguancun, Beijing, 100190, P. R. China.
authors.forename: Yuanchang
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Yang
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China.
authors.forename: Kunlin
authors.initials: K
authors.lastname: Wang
authors.affiliation: State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, P. R. China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zhu
authors.affiliation: National Center for Nanoscience and Technology, Zhongguancun, Beijing, 100190, P. R. China.|CAS Center for Excellence in Brain Science and Intelligence Technology, 320 Yue Yang Road, Shanghai, 200031, P. R. China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Fang
keywords: detectivity; graphene; heterojunctions; noise spectra; photodetectors