Graphene–Ruthenium Complex Hybrid Photodetectors with Ultrahigh Photoresponsivity |
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Authors: | Xien Liu Eun Kwang Lee Joon Hak Oh |
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Affiliation: | 1. School of Energy and Chemical Engineering, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), , Ulsan, 689‐798 Republic of Korea;2. Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), , Pohang, 790‐784 Republic of Korea |
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Abstract: | The maximum responsivity of a pure monolayer graphene‐based photodetector is currently less than 10 mA W?1 because of small optical absorption and short recombination lifetime. Here, a graphene hybrid photodetector functionalized with a photoactive ruthenium complex that shows an ultrahigh responsivity of ≈1 × 105 A W?1 and a photoconductive gain of ≈3 × 106 under incident optical intensity of the order of sub‐milliwatts is reported. This responsivity is two orders of magnitude higher than the precedent best performance of graphene‐based photodetectors under a similar incident light intensity. Upon functionalization with a 4‐nm‐thick ruthenium complex, monolayer graphene‐based photodetectors exhibit pronounced n‐type doping effect due to electron transfer via the metal?ligand charge transfer (MLCT) from the ruthenium complex to graphene. The ultrahigh responsivity is attributed to the long lifetime and high mobility of the photoexcited charge carriers. This approach is highly promising for improving the responsivity of graphene‐based photodetectors. |
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Keywords: | graphene– ruthenium complex field‐effect transistors photodetectors phototransistors |
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