We conduct a study on the superlinear transport of multilayer graphene channels that partially or completely locate on silicon which is pre-etched by inductively coupled plasma (ICP). By fabricating a multilayer-gra...We conduct a study on the superlinear transport of multilayer graphene channels that partially or completely locate on silicon which is pre-etched by inductively coupled plasma (ICP). By fabricating a multilayer-graphene field-effect transistor on a Si/SiO2 substrate, we obtain that the superlinearity results from the interaction between the multilayer graphene sheet and the ICP-etched silicon, In addition, the observed superlinear transport of the device is found to be consistent with the prediction of Schwinger's mechanism. In the high bias regime, the values of a increase draxnatically from 1.02 to 1.40. The strength of the electric field corresponding to the on-start of electron-hole pair production is calculated to be 5 × 10^4 Vim. Our work provides an experimental observation of the nonlinear transport of the multilayer graphene.展开更多
We theoretically investigate the transport property of graphene surface plasmon polaritons(GSPPs) on curved graphene substrates. The dispersion relationship, propagation length, and field confinement are calculated by...We theoretically investigate the transport property of graphene surface plasmon polaritons(GSPPs) on curved graphene substrates. The dispersion relationship, propagation length, and field confinement are calculated by an analytical method and compared with those on planar substrates. Based on our theory, the bend of graphene nearly does not affect the property of GSPPs except for an extremely small shift to the lower frequency for the same effective mode index. The field distributions and the eigenfrequencies of GSPPs on planar and cylindrical substrates are calculated by the finite element method, which validates our theoretical analysis. Moreover, three types of graphene-guided optical interconnections of GSPPs, namely, planar to curved graphene film, curved to planar graphene film, and curved to curved graphene film, are proposed and examined in detail. The theoretical results show that the GSPPs propagation on curved graphene substrates and interconnections will not induce any additional losses if the phase-matching condition is satisfied. Additionally, the extreme tiny size of curved graphene for interconnection at a certain spectra range is predicted by our theory and validated by the simulation of 90° turning of GSPPs. The bending effect on the property of GSPPs is systematically analyzed and identified. Our studies would be helpful to instruct design of plasmonic devices involving curved GSPPs, such as nanophotoniccircuits, flexible plasmonic, and biocompatible devices.展开更多
Inspired by nature,precise spatial organization of enzyme cascades of interest is crucial to the improvement of catalytic performance.Herein,DNA scaffolds were introduced to construct a toolkit for versatile immobiliz...Inspired by nature,precise spatial organization of enzyme cascades of interest is crucial to the improvement of catalytic performance.Herein,DNA scaffolds were introduced to construct a toolkit for versatile immobilization of enzyme pairs on dextran-coated magnetic nanoparticles(MNPs).After the glucose oxidase(GOx)and horseradish peroxidase(HRP)pair was immobilized through random cova-lent,DNA-directed and DNA tile-directed strategies,the immobilized GOx/HRP pair on the MNP-based carrier assembled with DNA tile(TD@MNPs)exhibited the highest activity due to rational spatial organization and less conformational change of constituent enzymes.With a decrease in interenzyme distance on TD@MNPs,furthermore,the catalytic efficiency of the HRP/GOx pair increased further for both substrates,2,2'-azinobis(3-ethyl-benzthiazoline-6-sulfonate)(ABTS)and 3,3',5,5'-tetramethyl benzidine(TMB).As the assembled HRP was closer to the carrier surface,the catalytic efficiency of the GOx/HRP pair increased by 6.2-fold for positively charged TMB and only by 62%for negatively charged ABTS compared with the free GOx/HRP pair.Moreover,a reversal of catalytic efficiency was found after the GOx/HRP pair was assembled on a positively charged carrier(TD@pMNPs).This research demonstrated that MNP-based car-riers had the potential to become a versatile toolkit for shedding an insight into catalytic performance and the development of new biocatalysts.展开更多
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFB0402404the High-Tech Research and Development Program of China under Grant Nos 2013AA031401,2015AA016902 and 2015AA016904the National Natural Science Foundation of China under Grant Nos 61674136,61176053,61274069 and 61435002
文摘We conduct a study on the superlinear transport of multilayer graphene channels that partially or completely locate on silicon which is pre-etched by inductively coupled plasma (ICP). By fabricating a multilayer-graphene field-effect transistor on a Si/SiO2 substrate, we obtain that the superlinearity results from the interaction between the multilayer graphene sheet and the ICP-etched silicon, In addition, the observed superlinear transport of the device is found to be consistent with the prediction of Schwinger's mechanism. In the high bias regime, the values of a increase draxnatically from 1.02 to 1.40. The strength of the electric field corresponding to the on-start of electron-hole pair production is calculated to be 5 × 10^4 Vim. Our work provides an experimental observation of the nonlinear transport of the multilayer graphene.
基金supported by the 973 Program of China (nos. 2013CB632704 and 2011CB922002)the National Natural Science Foundation of China (no. 11204365)
文摘We theoretically investigate the transport property of graphene surface plasmon polaritons(GSPPs) on curved graphene substrates. The dispersion relationship, propagation length, and field confinement are calculated by an analytical method and compared with those on planar substrates. Based on our theory, the bend of graphene nearly does not affect the property of GSPPs except for an extremely small shift to the lower frequency for the same effective mode index. The field distributions and the eigenfrequencies of GSPPs on planar and cylindrical substrates are calculated by the finite element method, which validates our theoretical analysis. Moreover, three types of graphene-guided optical interconnections of GSPPs, namely, planar to curved graphene film, curved to planar graphene film, and curved to curved graphene film, are proposed and examined in detail. The theoretical results show that the GSPPs propagation on curved graphene substrates and interconnections will not induce any additional losses if the phase-matching condition is satisfied. Additionally, the extreme tiny size of curved graphene for interconnection at a certain spectra range is predicted by our theory and validated by the simulation of 90° turning of GSPPs. The bending effect on the property of GSPPs is systematically analyzed and identified. Our studies would be helpful to instruct design of plasmonic devices involving curved GSPPs, such as nanophotoniccircuits, flexible plasmonic, and biocompatible devices.
基金the National Key Research and Development Program of China(No.2021YFC2102801)the National Natural Science Foundation of China(No.21878221)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.21621004).
文摘Inspired by nature,precise spatial organization of enzyme cascades of interest is crucial to the improvement of catalytic performance.Herein,DNA scaffolds were introduced to construct a toolkit for versatile immobilization of enzyme pairs on dextran-coated magnetic nanoparticles(MNPs).After the glucose oxidase(GOx)and horseradish peroxidase(HRP)pair was immobilized through random cova-lent,DNA-directed and DNA tile-directed strategies,the immobilized GOx/HRP pair on the MNP-based carrier assembled with DNA tile(TD@MNPs)exhibited the highest activity due to rational spatial organization and less conformational change of constituent enzymes.With a decrease in interenzyme distance on TD@MNPs,furthermore,the catalytic efficiency of the HRP/GOx pair increased further for both substrates,2,2'-azinobis(3-ethyl-benzthiazoline-6-sulfonate)(ABTS)and 3,3',5,5'-tetramethyl benzidine(TMB).As the assembled HRP was closer to the carrier surface,the catalytic efficiency of the GOx/HRP pair increased by 6.2-fold for positively charged TMB and only by 62%for negatively charged ABTS compared with the free GOx/HRP pair.Moreover,a reversal of catalytic efficiency was found after the GOx/HRP pair was assembled on a positively charged carrier(TD@pMNPs).This research demonstrated that MNP-based car-riers had the potential to become a versatile toolkit for shedding an insight into catalytic performance and the development of new biocatalysts.