The Experts below are selected from a list of 99978 Experts worldwide ranked by ideXlab platform
Gregor Schwartz - One of the best experts on this subject based on the ideXlab platform.
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large area transparent and flexible infrared Photodetector fabricated using p n junctions formed by n doping chemical vapor deposition grown graphene
Nano Letters, 2014Co-Authors: He Tian, Gregor SchwartzAbstract:Graphene is a highly promising material for high speed, broadband, and multicolor photodetection. Because of its lack of bandgap, individually gated P- and N-regions are needed to fabricate Photodetectors. Here we report a technique for making a large-area Photodetector on the basis of controllable fabrication of graphene P-N junctions. Our selectively doped chemical vapor deposition (CVD) graphene Photodetector showed a ∼5% modulation of conductance under global IR irradiation. By comparing devices of various geometries, we identify that both the homogeneous and the P-N junction regions contribute competitively to the photoresponse. Furthermore, we demonstrate that our two-terminal graphene Photodetector can be fabricated on both transparent and flexible substrates without the need for complex fabrication processes used in electrically gated three-terminal devices. This represents the first demonstration of a fully transparent and flexible graphene-based IR Photodetector that exhibits both good photoresp...
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Large-area, transparent, and flexible infrared Photodetector fabricated using P-N junctions formed by N-doping chemical vapor deposition grown graphene
Nano Letters, 2014Co-Authors: Nan Liu, Gregor Schwartz, Jeffrey B.-h. Tok, Tian-ling Ren, He Tian, Zhenan BaoAbstract:Graphene is a highly promising material for high speed, broadband, and multicolor photodetection. Because of its lack of bandgap, individually gated P- and N-regions are needed to fabricate Photodetectors. Here we report a technique for making a large-area Photodetector on the basis of controllable fabrication of graphene P-N junctions. Our selectively doped chemical vapor deposition (CVD) graphene Photodetector showed a ∼5% modulation of conductance under global IR irradiation. By comparing devices of various geometries, we identify that both the homogeneous and the P-N junction regions contribute competitively to the photoresponse. Furthermore, we demonstrate that our two-terminal graphene Photodetector can be fabricated on both transparent and flexible substrates without the need for complex fabrication processes used in electrically gated three-terminal devices. This represents the first demonstration of a fully transparent and flexible graphene-based IR Photodetector that exhibits both good photoresponsivity and high bending capability. This simple approach should facilitate the development of next generation high-performance IR Photodetectors.
Li Zhang - One of the best experts on this subject based on the ideXlab platform.
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high detectivity graphene silicon heterojunction Photodetector
Small, 2016Co-Authors: Xinming Li, Mingde Du, Yuanchang Li, Zheng Lv, Yao Yang, Xiao Li, Tingting Yang, Kunlin Wang, Li Zhang, Ying FangAbstract:: 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.
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High Detectivity Graphene-Silicon Heterojunction Photodetector
Small, 2016Co-Authors: Xinming Li, Mingde Du, Yuanchang Li, Miao Zhu, Zheng Lv, Yao Yang, Xiao Li, Tingting Yang, Li Zhang, Kunlin WangAbstract: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 $5.77\times10^{13}$ cm Hz1/2 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.
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pentacene based Photodetector in visible region with vertical field effect transistor configuration
IEEE Photonics Technology Letters, 2015Co-Authors: Dan Yang, Li Zhang, Haowei Wang, Yishan Wang, Zhixiao Li, Taojian Song, Chunjie Fu, Shengyi YangAbstract:Electrical and detection performances of pentacene-based Photodetector with vertical field-effect transistor (VFET) configuration were investigated in full visible region. By comparing with planar FET-based Photodetector ITO/ PMMA(520 nm)/Pentacene(35 nm)/Au, the VFET-based photo-detector ITO/Pentacene(80 nm)/Al(15 nm)/Pentacene(80 nm)/ Au exhibits better performance. At an output current of ca. $-8\times 10^{-7}$ A, the threshold voltage ( $V_{\rm th}$ ) was −0.61 V for the VFET-based device at $V_{\mathrm {DS}} = -2$ V, but $V_{\mathrm {th}} = -7.1$ V for the planar one at $V_{\mathrm {DS}} = -12$ V. The performance of Photodetectors depends on incident monochromatic light, and the VFET-based Photodetector showed a maximum responsivity of 188 mA/W and a photosensitivity peak of 588 under 350-nm light, which were $\sim 11.75$ and 2.83 times as that of the planar one, respectively. Therefore, it provides an easy way to get the VFET-based organic Photodetectors in full visible region with excellent photosensitivity, responsivity, and light selectivity, showing its promising application in all-organic image sensors working at low voltages.
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Pentacene-Based Photodetector in Visible Region With Vertical Field-Effect Transistor Configuration
IEEE Photonics Technology Letters, 2015Co-Authors: Dan Yang, Li Zhang, Haowei Wang, Yishan Wang, Zhixiao Li, Taojian Song, Chunjie Fu, Shengyi YangAbstract:Electrical and detection performances of pentacene-based Photodetector with vertical field-effect transistor (VFET) configuration were investigated in full visible region. By comparing with planar FET-based Photodetector ITO/ PMMA(520 nm)/Pentacene(35 nm)/Au, the VFET-based Photodetector ITO/Pentacene(80 nm)/Al(15 nm)/Pentacene(80 nm)/ Au exhibits better performance. At an output current of ca. -8 × 10-7 A, the threshold voltage (Vth) was -0.61 V for the VFET-based device at VDS = -2 V, but Vth = -7.1 V for the planar one at VDS = -12 V. The performance of Photodetectors depends on incident monochromatic light, and the VFET-based Photodetector showed a maximum responsivity of 188 mA/W and a photosensitivity peak of 588 under 350-nm light, which were ~11.75 and 2.83 times as that of the planar one, respectively. Therefore, it provides an easy way to get the VFET-based organic Photodetectors in full visible region with excellent photosensitivity, responsivity, and light selectivity, showing its promising application in all-organic image sensors working at low voltages.
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influence of the dielectric pmma layer on the detectivity of pentacene based Photodetector with field effect transistor configuration in visible region
IEEE Photonics Journal, 2013Co-Authors: Dan Yang, Li Zhang, Shengyi YangAbstract:In this paper, the influence of dielectric polymethylmethacrylate (PMMA) layer on the detectivity of pentacene-based Photodetectors with field-effect transistor (FET) configuration were investigated in a visible region. By changing the thickness of the PMMA layer, from 230 nm to 520 nm and 800 nm, electrical parameters, such as the capacitance, “on/off” current ratio, and carrier mobility, of the pentacene-based Photodetector decrease with increasing the thickness of the PMMA layer, which influences its detectivity directly. The photosensitivity and responsivity of the FET-based pentacene Photodetector with 520-nm PMMA varied with incident monochromatic light from 350 nm to 750 nm, and it showed a maximum responsivity of 149 mA/W with a photosensitivity peak of 1.7 ×104 at 450 nm, which is of the same order as that of the standard Si-based Photodetector. Therefore, it is an applicable way to get such kind of FET-based full-organic Photodetectors in a full visible region with excellent photosensitivity, responsivity, and selectivity.
Shengyi Yang - One of the best experts on this subject based on the ideXlab platform.
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pentacene based Photodetector in visible region with vertical field effect transistor configuration
IEEE Photonics Technology Letters, 2015Co-Authors: Dan Yang, Li Zhang, Haowei Wang, Yishan Wang, Zhixiao Li, Taojian Song, Chunjie Fu, Shengyi YangAbstract:Electrical and detection performances of pentacene-based Photodetector with vertical field-effect transistor (VFET) configuration were investigated in full visible region. By comparing with planar FET-based Photodetector ITO/ PMMA(520 nm)/Pentacene(35 nm)/Au, the VFET-based photo-detector ITO/Pentacene(80 nm)/Al(15 nm)/Pentacene(80 nm)/ Au exhibits better performance. At an output current of ca. $-8\times 10^{-7}$ A, the threshold voltage ( $V_{\rm th}$ ) was −0.61 V for the VFET-based device at $V_{\mathrm {DS}} = -2$ V, but $V_{\mathrm {th}} = -7.1$ V for the planar one at $V_{\mathrm {DS}} = -12$ V. The performance of Photodetectors depends on incident monochromatic light, and the VFET-based Photodetector showed a maximum responsivity of 188 mA/W and a photosensitivity peak of 588 under 350-nm light, which were $\sim 11.75$ and 2.83 times as that of the planar one, respectively. Therefore, it provides an easy way to get the VFET-based organic Photodetectors in full visible region with excellent photosensitivity, responsivity, and light selectivity, showing its promising application in all-organic image sensors working at low voltages.
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Pentacene-Based Photodetector in Visible Region With Vertical Field-Effect Transistor Configuration
IEEE Photonics Technology Letters, 2015Co-Authors: Dan Yang, Li Zhang, Haowei Wang, Yishan Wang, Zhixiao Li, Taojian Song, Chunjie Fu, Shengyi YangAbstract:Electrical and detection performances of pentacene-based Photodetector with vertical field-effect transistor (VFET) configuration were investigated in full visible region. By comparing with planar FET-based Photodetector ITO/ PMMA(520 nm)/Pentacene(35 nm)/Au, the VFET-based Photodetector ITO/Pentacene(80 nm)/Al(15 nm)/Pentacene(80 nm)/ Au exhibits better performance. At an output current of ca. -8 × 10-7 A, the threshold voltage (Vth) was -0.61 V for the VFET-based device at VDS = -2 V, but Vth = -7.1 V for the planar one at VDS = -12 V. The performance of Photodetectors depends on incident monochromatic light, and the VFET-based Photodetector showed a maximum responsivity of 188 mA/W and a photosensitivity peak of 588 under 350-nm light, which were ~11.75 and 2.83 times as that of the planar one, respectively. Therefore, it provides an easy way to get the VFET-based organic Photodetectors in full visible region with excellent photosensitivity, responsivity, and light selectivity, showing its promising application in all-organic image sensors working at low voltages.
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influence of the dielectric pmma layer on the detectivity of pentacene based Photodetector with field effect transistor configuration in visible region
IEEE Photonics Journal, 2013Co-Authors: Dan Yang, Li Zhang, Shengyi YangAbstract:In this paper, the influence of dielectric polymethylmethacrylate (PMMA) layer on the detectivity of pentacene-based Photodetectors with field-effect transistor (FET) configuration were investigated in a visible region. By changing the thickness of the PMMA layer, from 230 nm to 520 nm and 800 nm, electrical parameters, such as the capacitance, “on/off” current ratio, and carrier mobility, of the pentacene-based Photodetector decrease with increasing the thickness of the PMMA layer, which influences its detectivity directly. The photosensitivity and responsivity of the FET-based pentacene Photodetector with 520-nm PMMA varied with incident monochromatic light from 350 nm to 750 nm, and it showed a maximum responsivity of 149 mA/W with a photosensitivity peak of 1.7 ×104 at 450 nm, which is of the same order as that of the standard Si-based Photodetector. Therefore, it is an applicable way to get such kind of FET-based full-organic Photodetectors in a full visible region with excellent photosensitivity, responsivity, and selectivity.
He Tian - One of the best experts on this subject based on the ideXlab platform.
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large area transparent and flexible infrared Photodetector fabricated using p n junctions formed by n doping chemical vapor deposition grown graphene
Nano Letters, 2014Co-Authors: He Tian, Gregor SchwartzAbstract:Graphene is a highly promising material for high speed, broadband, and multicolor photodetection. Because of its lack of bandgap, individually gated P- and N-regions are needed to fabricate Photodetectors. Here we report a technique for making a large-area Photodetector on the basis of controllable fabrication of graphene P-N junctions. Our selectively doped chemical vapor deposition (CVD) graphene Photodetector showed a ∼5% modulation of conductance under global IR irradiation. By comparing devices of various geometries, we identify that both the homogeneous and the P-N junction regions contribute competitively to the photoresponse. Furthermore, we demonstrate that our two-terminal graphene Photodetector can be fabricated on both transparent and flexible substrates without the need for complex fabrication processes used in electrically gated three-terminal devices. This represents the first demonstration of a fully transparent and flexible graphene-based IR Photodetector that exhibits both good photoresp...
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Large-area, transparent, and flexible infrared Photodetector fabricated using P-N junctions formed by N-doping chemical vapor deposition grown graphene
Nano Letters, 2014Co-Authors: Nan Liu, Gregor Schwartz, Jeffrey B.-h. Tok, Tian-ling Ren, He Tian, Zhenan BaoAbstract:Graphene is a highly promising material for high speed, broadband, and multicolor photodetection. Because of its lack of bandgap, individually gated P- and N-regions are needed to fabricate Photodetectors. Here we report a technique for making a large-area Photodetector on the basis of controllable fabrication of graphene P-N junctions. Our selectively doped chemical vapor deposition (CVD) graphene Photodetector showed a ∼5% modulation of conductance under global IR irradiation. By comparing devices of various geometries, we identify that both the homogeneous and the P-N junction regions contribute competitively to the photoresponse. Furthermore, we demonstrate that our two-terminal graphene Photodetector can be fabricated on both transparent and flexible substrates without the need for complex fabrication processes used in electrically gated three-terminal devices. This represents the first demonstration of a fully transparent and flexible graphene-based IR Photodetector that exhibits both good photoresponsivity and high bending capability. This simple approach should facilitate the development of next generation high-performance IR Photodetectors.
Xinming Li - One of the best experts on this subject based on the ideXlab platform.
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Synergistic Effects of Plasmonics and Electron Trapping in Graphene Short-Wave Infrared Photodetectors with Ultrahigh Responsivity
ACS Nano, 2017Co-Authors: Zefeng Chen, Lay Kee Ang, Chester Shu, Shi Jun Liang, Mingzhu Long, Xinming Li, Li Tao, Jiaqi Wang, Hon Ki Tsang, Jian-bin XuAbstract:Graphene’s unique electronic and optical properties have made it an attractive material for developing ultrafast short-wave infrared (SWIR) Photodetectors. However, the performance of graphene SWIR Photodetectors has been limited by the low optical absorption of graphene as well as the ultrashort lifetime of photoinduced carriers. Here, we present two mechanisms to overcome these two shortages and demonstrate a graphene-based SWIR Photodetector with high responsivity and fast photoresponse. In particular, a vertical built-in field is employed in the graphene channel for trapping the photoinduced electrons and leaving holes in graphene, which results in prolonged photoinduced carrier lifetime. On the other hand, plasmonic effects were employed to realize photon trapping and enhance the light absorption of graphene. Thanks to the above two mechanisms, the responsivity of this proposed SWIR Photodetector is up to a record of 83 A/W at a wavelength of 1.55 μm with a fast rising time of less than 600 ns. This ...
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high detectivity graphene silicon heterojunction Photodetector
Small, 2016Co-Authors: Xinming Li, Mingde Du, Yuanchang Li, Zheng Lv, Yao Yang, Xiao Li, Tingting Yang, Kunlin Wang, Li Zhang, Ying FangAbstract:: 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.
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High Detectivity Graphene-Silicon Heterojunction Photodetector
Small, 2016Co-Authors: Xinming Li, Mingde Du, Yuanchang Li, Miao Zhu, Zheng Lv, Yao Yang, Xiao Li, Tingting Yang, Li Zhang, Kunlin WangAbstract: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 $5.77\times10^{13}$ cm Hz1/2 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.
