Local and Nonlocal Optically Induced Transparency Effects in Graphene–Silicon Hybrid Nanophotonic Integrated Circuits

Yu, Longhai; Zheng, Jiajiu; Xu, Yang; Dai, Daoxin; He, Sailing

doi:10.1021/nn504377m

Cited by 64 publications

(58 citation statements)

References 43 publications

(82 reference statements)

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“…The results are displayed in Figure 4 d. Even when the laser spot is not in the region of the heterostructure, whereas on the silicon, a photocurrent still exists, which is consistent with the very recent report. [ 41 ] As the laser spot comes close to graphene, the response time becomes shorter. The time scale is about hundreds microsecond, which is relevant to the response time of the third process in the photoresponse under 632 nm laser illumination.…”

Section: Communicationmentioning

confidence: 99%

High Responsivity, Broadband, and Fast Graphene/Silicon Photodetector in Photoconductor Mode

Chen

Cheng

Wang

et al. 2015

Advanced Optical Materials

147

102

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COMMUNICATIONIn this paper, we present a highly broadband (from visible to infrared) photodetector based on chemical vapor deposition (CVD) graphene-silicon heterostructure, together to be operated in photoconductor mode. This device shows very high responsivity (>10 4 A W −1 ) at wavelength of 632 nm, where light absorption relies on silicon. More importantly, even in the infrared region (1550 nm), where light absorption only depends on the graphene, the responsivity of our detector can be as high as 0.23 A W −1 , which is much higher those by pure monolayer graphene-based devices without optically assisted structure in this spectral region. [ 13,15,24 ] The signifi cant response is mainly due to the fact that the built-in fi eld in heterostructure can effectively prolong the ultrashort lifetime of photon-induced carriers. Besides, we also fi nd three dynamic processes in the transient response: photo-induced carriers sweeping into graphene by the built-in fi eld, electrons in the depletion region diffusion back to graphene, and photo-induced carriers in the bulk silicon diffusion to graphene. Due to the fi rst mechanism, the response time of our detector is less than 3 µs, which has not been reported among graphene photoconductor/ phototransistors. [ 1 ] The structure of graphene-silicon heterostructural photodetector is schematically shown in Figure 1 a. The start wafer we employed is a lightly doped p-type silicon wafer (>100 Ω). A thin layer of SiO 2 is grown on silicon and patterned a window on top. Then, the CVD graphene (the Raman spectra is shown in Figure S1, Supporting Information) is transferred, and both electrodes are deposited on graphene. The SiO 2 layer can avoid the overlap between the electrode and silicon. A Schottky junction is thus formed at the interface between graphene and silicon. The Fermi level differences are measured by Kelvin probe force microscopy (KPFM) in the dark. As shown in Figure 1 b, the surface potential differences (approximately similar to the work function misalignment for clean samples) between graphene and silicon, and between graphene and gold are about 0.08 and 0.16 eV, respectively. Under ambient conditions, the work function of gold is around 4.8 to 4.9 eV. [ 25,26 ] By taking the intrinsic work function of graphene (≈4.56 eV) [30][31][32] into consideration, an energy band diagram is depicted in Figure 1 c. The Fermi energy of graphene should be around 0.16 to 0.26 eV. A built-in fi eld forms at the surface, which directs from silicon to graphene. The graphene not only functions as the charge transport channel, but also works as the light absorber for the light with photon energy lower than the Fermi energy.In the visible light experiment, the photodetector is characterized by the laser at wavelength of 625 nm. Optical attenuators are introduced to change the input power. DOI: 10.1002/adom.201500127Graphene is thought to be an ideal material for novel photodetectors due to its unique properties. [1][2][3] For example, its zero bandgap affords the benefi t of ultr...

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Section: Communicationmentioning

confidence: 99%

High Responsivity, Broadband, and Fast Graphene/Silicon Photodetector in Photoconductor Mode

Chen

Cheng

Wang

et al. 2015

Advanced Optical Materials

147

102

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“…Due to its unique electronic and optical properties, graphene has offered a new paradigm for extremely fast and active optoelectronic devices [1][2][3][4][5][6][7], e.g., the tunability of graphene conductivity [8][9][10] allows to realize efficient electro-optical (E/O) modulation [11], and all-optical switching [12,13]. With the combination of high-index dielectric waveguides/resonators, several integrated graphene-based optical modulators have already been realized [14][15][16][17][18][19][20][21].…”

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confidence: 99%

Efficient electro-optic modulation in low-loss graphene-plasmonic slot waveguides

et al. 2017

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Surface plasmon polaritons enable light concentration within subwavelength regions, opening thereby new avenues for miniaturizing the device and strengthening light-matter interactions. Here we realize effective electro-optic modulation in low-loss plasmonic waveguides with the aid of graphene, and the devices are fully integrated in the silicon-on-insulator platform. By advantageously exploiting low-loss plasmonic slot-waveguide modes, which weakly leak into a substrate while feature strong fields within the two-layer-graphene covered slots in metal, we successfully achieve a tunability of 0.13 dB/µm for our fabricated graphene-plasmonic waveguide devices with extremely low insertion loss, which outperforms previously reported graphene-plasmonic devices. Our results highlight the potential of graphene plasmonic leaky-mode hybrid waveguides to realized active ultra-compact devices for optoelectronic applications.

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“…Furthermore, graphene can co-work with some conventional semiconductors to form a Schottky junction101112. When light illuminates the semiconductor/graphene Schottky junction13, the photo-carriers can transport from the conductor layer to the graphene layer by the build-in field. As a result, the graphene conduction changes according to equation, Δ σ = Δ neμ 14, where Δ n is the carrier- concentration variation in graphene, μ is the carrier mobility, e is the electron charge.…”

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confidence: 99%

Silicon-graphene conductive photodetector with ultra-high responsivity

Liu

Yin

et al. 2017

Sci Rep

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Graphene is attractive for realizing optoelectronic devices, including photodetectors because of the unique advantages. It can easily co-work with other semiconductors to form a Schottky junction, in which the photo-carrier generated by light absorption in the semiconductor might be transported to the graphene layer efficiently by the build-in field. It changes the graphene conduction greatly and provides the possibility of realizing a graphene-based conductive-mode photodetector. Here we design and demonstrate a silicon-graphene conductive photodetector with improved responsivity and response speed. An electrical-circuit model is established and the graphene-sheet pattern is designed optimally for maximizing the responsivity. The fabricated silicon-graphene conductive photodetector shows a responsivity of up to ~105 A/W at room temperature (27 °C) and the response time is as short as ~30 μs. The temperature dependence of the silicon-graphene conductive photodetector is studied for the first time. It is shown that the silicon-graphene conductive photodetector has ultra-high responsivity when operating at low temperature, which provides the possibility to detect extremely weak optical power. For example, the device can detect an input optical power as low as 6.2 pW with the responsivity as high as 2.4 × 107 A/W when operating at −25 °C in our experiment.

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Local and Nonlocal Optically Induced Transparency Effects in Graphene–Silicon Hybrid Nanophotonic Integrated Circuits

Cited by 64 publications

References 43 publications

High Responsivity, Broadband, and Fast Graphene/Silicon Photodetector in Photoconductor Mode

High Responsivity, Broadband, and Fast Graphene/Silicon Photodetector in Photoconductor Mode

Efficient electro-optic modulation in low-loss graphene-plasmonic slot waveguides

Silicon-graphene conductive photodetector with ultra-high responsivity

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