Graphene light modulators working at near-infrared wavelengths

Aznakayeva, D. E.; Rodríguez, Francisco; Marshall, Owen; Григоренко, А. Н.

doi:10.1364/oe.25.010255

Cited by 16 publications

(5 citation statements)

References 16 publications

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“…i.e., to achieve the same chemical potential μ c in the case of a SiO 2 layer, one needs to apply a voltage 6.4 times higher than that for the HfO 2 layer. In addition, taking into account the supercapacity effect shown for HfO 2 in [20], in a real experiment this difference can be even bigger. However, it is worth of noting that dielectric permittivity of a material chosen for the buffer layer should not be very high due to the fact that this will lead to high remnant polarization, high hysteresis, and long retention times of the buffer layer [29] which, in turn, will lead to a slowdown in operation of the device.…”

Section: Resultsmentioning

confidence: 97%

“…Moreover, graphene-supported devices have recently been considered as a subject for combining with a relatively well-established research field such as plasmonic biosensors, which also revealed new intriguing features [15]. Additionally, because the graphene layer itself can support different kind of plasmonic resonances, graphene plasmonics has emerged recently as a promising field to further advance the applications [16][17][18][19][20][21][22]. In the present work, we aimed to further increase the actively controlled modulation depth of graphene-based optical modulators/switchers and to simultaneously reduce the applied voltage V g required to achieve maximum modulation values.…”

Section: Introductionmentioning

confidence: 99%

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Temperature-dependent effect of modulation in graphene-supported metamaterials

et al. 2022

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We report on a novel effect of temperature-dependent modulation in graphene-supported metamaterials. The effect was observed during the theoretical analysis of a model graphene-supported electro-optical modulator having silicon dioxide (SiO2) or hafnium dioxide (HfO2) as a buffer dielectric layer. Comparative analysis of the two materials showed that they provide approximately the same maximum values for transmission and reflection modulation depths. However, in the case of a HfO2 buffer layer, a lower chemical potential of the graphene is required to achieve the maximum value. Moreover, theoretical calculations revealed that a lower gate voltage (up to 6.4 times) is required to be applied in the case of a HfO2 layer to achieve the same graphene chemical potential. The graphene layer was found to possesses high absorption (due to the additional resonance excitation) for some values of chemical potential and this effect is extremely temperature dependent. The discovered modulation effect was demonstrated to further increase the transmission modulation depth for the simple model structure up to 2.7 times (from 18.4 to 50.1 %), while for the reflection modulation depth, this enhancement was equal to 2.2 times (from 24.4 to 52.8 %). The novel modulation effect could easily be adopted and applied over a wide range of metadevices which would serve as a quick booster for the development of related research areas.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Temperature-dependent effect of modulation in graphene-supported metamaterials

et al. 2022

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“…This implies that the graphene flake increases the charge induced by a given gating voltage with time (which shifts the CNP voltage further away from the applied voltage position). Hence, one can describe the negative hysteresis of an undoped graphene sample by an increase of the capacitance of the dielectric layer with time, 23 which leads to the formation of a supercapacitor. 24 Alternatively, the negative gating hysteresis of an originally undoped sample could be observed at a fixed applied gate voltage as a decrease of the graphene resistance with time caused by the shift of CNP voltage away from the applied voltage position.…”

Section: Resultsmentioning

confidence: 99%

Effect of Dielectric Fabrication Techniques on Graphene Gating

Kravets

Imaizumi

et al. 2020

J. Phys. Chem. C

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One of the exciting features of graphene is a possibility to affect its electrical, optical, and chemical properties by gating, that is, by application of an electric field. This requires reasonably large fields (at the level of 1 V/nm necessary to induce relevant electron density changes) applied over a gating dielectric material. At these fields, most dielectrics show some conduction, which leads to an important question: what is the best dielectric to gate graphene? Here, we show that this question is imprecise as a dielectric material produced by different fabrication methods can exhibit dramatically different gating properties. Namely, we show that two oxide dielectrics (hafnia and alumina) result in positive hysteresis of graphene gating characteristics being fabricated by atomic layer deposition and negative hysteresis being fabricated by electron beam evaporation. We attribute this behavior to the stoichiometry of the samples and oxygen ion migration. It implies that oxide dielectrics should be avoided in graphene gated devices working at room temperatures.

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“…The presence of an additional dielectric layer in a SPR structure can lead to complications connected with large electric fields induced in the layers. In our recent works [21][22][23], we have shown that electric double-layers (or ion traps) at the interfaces of metal-dielectric and dielectricgraphene can be easily formed. Due to this effect, it is possible to enhance the charge induced in graphene and hence to affect its properties.…”

Section: Introductionmentioning

confidence: 99%

Metal-Dielectric-Graphene Hybrid Heterostructures with Enhanced Surface Plasmon Resonance Sensitivity Based on Amplitude and Phase Measurements

Kravets

et al. 2022

Plasmonics

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Metal-dielectric-graphene hybrid heterostructures based on oxides Al2O3, HfO2, and ZrO2 as well as on complementary metal–oxide–semiconductor compatible dielectric Si3N4 covering plasmonic metals Cu and Ag have been fabricated and studied. We show that the characteristics of these heterostructures are important for surface plasmon resonance biosensing (such as minimum reflectivity, sharp phase changes, resonance full width at half minimum and resonance sensitivity to refractive index unit (RIU) changes) can be significantly improved by adding dielectric/graphene layers. We demonstrate maximum plasmon resonance spectral sensitivity of more than 30,000 nm/RIU for Cu/Al2O3 (ZrO2, Si3N4), Ag/Si3N4 bilayers and Cu/dielectric/graphene three-layers for near-infrared wavelengths. The sensitivities of the fabricated heterostructures were ~ 5–8 times higher than those of bare Cu or Ag thin films. We also found that the width of the plasmon resonance reflectivity curves can be reduced by adding dielectric/graphene layers. An unexpected blueshift of the plasmon resonance spectral position was observed after covering noble metals with high-index dielectric/graphene heterostructures. We suggest that the observed blueshift and a large enhancement of surface plasmon resonance sensitivity in metal-dielectric-graphene hybrid heterostructures are produced by stationary surface dipoles which generate a strong electric field concentrated at the very thin top dielectric/graphene layer.

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Graphene light modulators working at near-infrared wavelengths

Cited by 16 publications

References 16 publications

Temperature-dependent effect of modulation in graphene-supported metamaterials

Temperature-dependent effect of modulation in graphene-supported metamaterials

Effect of Dielectric Fabrication Techniques on Graphene Gating

Metal-Dielectric-Graphene Hybrid Heterostructures with Enhanced Surface Plasmon Resonance Sensitivity Based on Amplitude and Phase Measurements

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