Single-Nanoparticle Plasmonic Electro-optic Modulator Based on

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Single Nanoparticle Plasmonic ElectroOptic Modulator Based on MoS2 Monolayers Bowen Li, Shuai Zu, Jiadong Zhou, Qiao Jiang, Bowen Du, Hangyong Shan, Yang Luo, Zheng Liu, Xing Zhu, and Zheyu Fang ACS Nano, Just Accepted Manuscript • DOI: 10.1021/acsnano.7b05479 • Publication Date (Web): 01 Sep 2017 Downloaded from http://pubs.acs.org on September 2, 2017

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Single Nanoparticle Plasmonic Electro-Optic Modulator Based on MoS2 Monolayers Bowen Li 1†, Shuai Zu1†, Jiadong Zhou2, Qiao Jiang1, Bowen Du1, Hangyong Shan1, Yang Luo1, Zheng Liu2, Xing Zhu1, and Zheyu Fang1,* 1

School of Physics, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China. 2

Center for Programmable Materials, School of Electrical and Electronic Engineering, Nanyang Technology University, Singapore 639798. [email protected] †These authors contributed equally to this work.

ABSTRACT: The manipulation of light in an integrated circuit is crucial for the developing of high speed electro-optic device. Recently, molybdenum disulfide (MoS2) monolayers generated broad interests for the opto-electronics because of its huge exciton binding energy, tunable optical emission, direct electronic bandgap structure, etc. Miniaturization and multi-functionality of the electro-optic device further requires the manipulation of light-matter interaction at single nanoparticle level. The strong exciton-plasmon interaction that generated between the MoS2 monolayers and metallic nanostructures, may be a possible solution for the compact electro-optic device at nanoscale. Here, we demonstrate a nanoplasmonic modulator 1 ACS Paragon Plus Environment

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in the visible spectral region by combining the MoS2 monolayers with a single Au nanodisk. The narrow MoS2 excitons coupled with broad Au plasmons results in a deep Fano resonance, which can be switched on and off by applying different gate-voltages on the MoS2 monolayers. A reversible display device that based on this single nanoparticle modulator is demonstrated with a heptamer pattern that actively controlled by the external gates. Our work provides a potential application for the electro-optic modulation in the nanoscale, and promotes the development of gate-tunable nanoplasmonic devices in the future.

KEYWORDS: MoS2, exciton-plasmon interaction, electro-optic modulator, Fano resonance, trions

Plasmonics and transition metal dichalcogenides (TMDCs) are two of the most rapidly advancing research areas in nanophononics.1-4 Surface plasmons, with properties of nanoscale light confinement5 and electromagnetic field enhancement,6 have induced great applications in the plasmonic focusing,7 integrated waveguide,8 active modulation,9,10 hot electron photodetection,11 etc. Plasmonic Fano resonance as a coherent scattering phenomenon with an asymmetric line-shape, is caused by the interference between a bright broad mode and a dark narrow state,12 which has been widely used for biosensing,13 optical switching,14 and electromagnetically induced transparency (EIT).15 Recently, the Fano resonance was further investigated by using 2 ACS Paragon Plus Environment

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the metallic nanostructure interacted with the semiconductor quantum dots, where the strong coupling between the plasmon and exciton can generate a so-called ‘plexciton’ resonance,16-17 which provides potential applications for the quantum optical device. Meanwhile, the extraordinary properties of TMDCs materials have generated great interests in the opto-electronics community.18-20 Molybdenum disulfide (MoS2) monolayers have attracted tremendous interests in recent years because of their direct electronic bandgap structure,21-24 versatile optical transitions,25-27 and tunable mechanical properties.28, 29 Moreover, tightly bound excitons in the MoS2 monolayers makes it a good candidate for fundamental physical studies, and provides a significant opportunity to realize electro-optic device that operated in the visible spectral region.26, 30-34 The combination of plasmonic nanostructures with MoS2 monolayers shows a great application promise.23,

27, 35

The strong electromagnetic field associated with the

localized surface plasmon (LSP) resonance can be confined to the deep sub-wavelength space. Depositing metallic nanostructures onto the MoS2 monolayers can realize a stronger light-matter interaction,36-39 and has been used to produce significant advances for the photovoltaics,38 photodetection40, 41 and sensing.42 On the other side, the tightly bound trions (a quasi-particle that composed of two electrons and a hole) and excitons of the MoS2 monolayers can be tuned by the electrical doping, which has been successfully used to control the optical properties of MoS2 with an applied gate voltage.43 Therefore, the combination of the MoS2 monolayers and designed metallic nanostructure to realize the control of exciton-plasmon 3 ACS Paragon Plus Environment

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coupling could potentially generate broad interests in the design of compact plasmonic electro-optic modulator. However, the nanoscale modulator with ultra-high tunability and optical sensitivity requires the exciton-plasmon coupling at single nanoparticle level, thus the precisely control of the metallic particle size and position, as well as the electrode contacts, are quite challenging for the device design and fabrication. In this letter, we experimentally demonstrate a hybrid Au nanodisk/MoS2 platform that can realize nanoplasmonic electro-optic modulation at single particle level in the visible spectral region. The narrow MoS2 exciton coupled with the single plasmon dipole can result in an asymmetric Fano resonance, with its intensity and spectral position ultra-sensitive to the local perturbation, such as the refractive index change of the MoS2 monolayers, which can be effectively tuned by the applied gate voltage.43

RESULTS AND DISCUSSION

Figure 1a is the schematic of our nanoplasmonic electro-optic modulator. The chemical vapor deposition (CVD) grown MoS2 monolayers were exfoliated onto the SiO2/Si substrate by using the polymethylmethacrylate (PMMA) nanotransfer method, then the Au nanodisk with radius of 60 nm and thickness of 30 nm was fabricated on the MoS2 monolayers via E-beam lithography and following Au evaporation, as shown in the scanning electron microscopy (SEM) image of Figure S1. To improve the conductivity of the contact, the electrodes were deposited by 5 nm Ti followed by 70 nm Au, and then annealed at 200 °C in the Ar environment for 1 hr. 4 ACS Paragon Plus Environment

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The contact resistance between the MoS2 monolayers and electrodes was measured as 2.598 MΩ, which demonstrates a fine ohmic contact (see Figure S2). The Au electrode, far away from the sample area, is mainly used for bias voltage control. Figure 1b is the Raman and photoluminescence (PL) spectra of the tested MoS2 monolayers, where a strong PL emission shows at ~680 nm, and the in-plane (E12g) and out-of-plane (A1g) Raman modes appear at 390 cm-1 and 411 cm-1, respectively. Figure 1c is the absorption spectrum of the MoS2 monolayers with its characteristic peaks of A and B excitons at ~660 nm and ~610 nm, respectively (green line). The LSP resonance of the Au nanodisk is shown in the same panel as the yellow line. When the LSP is tuned close to the MoS2 A exciton, the near-field coupling strength between the MoS2 exciton and Au nanodisk plasmon can be dramatically increased, and finally results in a strong Fano resonance (orange line).

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Figure 1. (a) Schematic of the electro-optic modulator, where a single Au nanodisk with radius of 60 nm is deposited on the MoS2 monolayers. The coupling strength between single Au plasmon and MoS2 exciton can be effectively tuned by the gate voltage. (b) The PL spectrum of the MoS2 monolayers on the SiO2/Si substrate, which shows a strong emission peak at ~680 nm. Inset: corresponding Raman spectrum of the MoS2 monolayers. (c) Scattering spectra of the Au nanodisk with and without the MoS2 monolayers, and the absorption spectrum of the MoS2 monolayers (green line). The black dashed line represents the exciton-plasmon coupling region at ~660 nm. (d) The coupled oscillator model, which includes the LSP, neutral exciton and trion as three oscillators.

In the room temperature, the MoS2 A exciton usually is contributed from both the neutral exciton (A0) and trion (A-). With a negative gate bias, the MoS2 absorption is dominated by the enhanced neutral exciton resonance. The contribution of the trion 6 ACS Paragon Plus Environment

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emerges gradually when the applied voltage changes to zero and further increases to the positive value. Therefore, the MoS2 absorption can be continually tuned by the electrical doping, and further to be used for the modulation of the plasmon-exciton coupling strength. To intuitively understand this tunability, we can consider the Au LSP, MoS2 neutral exciton and trion as three classical coupled oscillators, as shown in Figure 1d. The oscillation strength of the neural exciton and trion can be effectively modified by the electrical doping, which can induce the change of coupling constants g1 and g2, and finally affects the intensity of the Fano resonance. More details about our oscillator model can be found in the Methods of theory calculation. A series of single Au nanodisks with different radii were fabricated to systematically investigate the exciton-plasmon interaction of this Au-MoS2 hybrid nanostructures, and the generated Fano resonance based on single nanodisk was measured by using the commercial hyperspectral dark-field imaging system (HIS V3, CytoViva Co.)

(see Figure S3a-c). The coupling efficiency of single nanoparticle

modulator is mainly determined by the scattering cross section in Au/MoS2 hybrids (see Figure S3 d-f). To achieve best coupling of incident photon, the size of the Au nanodisk need to be carefully tailored. The Au nanodisk with radius of 60 nm was selected for the following experiment, because its plasmon resonance overlaps with the MoS2 A exciton in the frequency domain and thus can be used for the strong plasmon-exciton coupling, which is also confirmed by the finite-difference time-domain (FDTD) simulations (see Figure S3d-f). To investigate the gate-dependence of this Fano resonance, reflection spectra 7 ACS Paragon Plus Environment

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of the pristine MoS2 monolayers at different gate voltages (Vg) were first tested as shown in Figure 2a and 2b, respectively, where the characteristic A exciton peak is found at ~668 nm when Vg = 0V. With the Vg changed from 0V to +8V, the absorption intensity of the A exciton decreases gradually, and with its spectrum peak red-shifted from 668 nm to 673 nm. When increasing the gate bias from 0V to -8V, the A exciton absorption increases, and a spectral blue-shifting from 668 nm to 665 nm is found.

Figure 2. (a,b) Reflection spectra of MoS2 monolayers with the gate voltage changed from +8V to -8V. An obvious and continuous spectral tuning was found under either positive (a) or negative gate voltages (b). (c,d) Scattering spectra of single Au nanodisk on the MoS2 monolayers with positive and negative gate voltages. As shown in (c), by increasing positive voltage from 0V to 8V, the Fano resonance is gradually


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weakened and finally turned off. Conversely, an enhanced Fano resonance is turned on by increasing negative voltage as shown in (d).

By exciting the single Au nanodisk that fabricated on the MoS2 monolayers, an asymmetric Fano resonance was recorded, as the narrow MoS2 excitons coupled with the broad Au dipolar mode. From Figure 2c, we can see that, for the positive gates, the coupling strength between the MoS2 A exciton and the single Au plasmon dipole decreases as the increasing of the gate bias. For the negative gates, the coupling between the exciton and plasmon was effectively enhanced when the voltage changed from 0V to -8V, and led to a deeper Fano resonance (Figure 2d). The Fano resonance usually has a frequency difference with the absorption dip of the MoS2, and due to the broadening of MoS2 exciton linewidth, the shift of the Fano resonance in Figure 2d could hardly be observed. To see more clearly the relation between the reflectance and scattering spectra, the reflectivity and scattering dip were extracted from Figure 2, and we plotted their variation as a function of the applied gate voltages in Figure S4. With the gate voltage increased from -8V to +8V, the reflectivity increases and the absorption of MoS2 decreases. The scattering dip of Au/MoS2 hybrids shows the similar tendency. These results demonstrate that this gate-dependent Fano resonance is strongly sensitive to the exciton-plasmon coupling strength. By controlling the MoS2 exciton absorption with different external gate voltages, one can realize this Fano resonance switched on and off, as shown in Figure 2c and 2d, respectively.


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As mentioned above, the absorption of the MoS2 monolayers for the A exciton is mainly contributed from both the neutral exciton and trion. To quantitatively investigate this gate-dependent Fano resonance, the behavior of both the neutral exciton and trion over the spectral range from 1.78 eV to 1.89 eV was fitted from the experimental measured MoS2 absorption spectra,44 as shown in Figure 3a. An overall suppression of the MoS2 A exciton absorption can be found within this spectral range when the gate voltage Vg is changed from -8V to +8V, where the neutral exciton diminishes rapidly and finally disappears to the background. For the trion, on the other hand, the resonance broadens gradually with the increasing of the gate voltage, and keeps its intensity almost unchanged. This dependency of the MoS2 absorption on the electronic doping level shows the gate-dependent tunability of the MoS2 A exciton, which is further used for the tuning of the plasmon-exciton coupling. After the Au nanodisk was fabricated on the MoS2 monolayers, the plasmon-exciton coupling happens under the excitation of incident light. The modified coupled oscillator model that introduced in Figure 1d, now can be used to describe the plasmon-exciton coupling behavior, and explain the origin of this gate-dependent Fano resonance. Because the dielectric constant ε(ω) of the MoS2 monolayers can be considered by a multi-Lorentzian model, both MoS2 absorption bands and LSP mode can be represented as multiple oscillators. As shown in Figure 1d, the LSP, neutral exciton (A0) and trion (A-) as three oscillators can have their respective resonance frequencies as ωLSP, ωAo and ωA-, and damping constants as γLSP, γAo and γA-.These three oscillators can be driven by the harmonic external forces as 10 ACS Paragon Plus Environment

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a1 e iω t , a 2 e iω t and a 3 e iω t . By coupling the LSP with the neutral exciton and trion

respectively via the spring with the real coupling constants as g1 and g2, the motion equation of this coupled oscillator model can be written as, 2  −ω 2 + iγ LSPω + ω LSP  g1   g2 

g1

  x1   a1      0   x2  =  a 2  ,  −ω 2 + iγ A− ω + ω A2 −   x3   a3  g2

−ω + iγ A0 ω A0 + ω 2

0

2 A0

where xi (i=1,2,3) represents the oscillation amplitude of each coupled oscillator. By solving the above equation, we can further calculate the sum of the squared modulus 3

2

of the amplitudes ∑ xi ( ω ) , which represents the overall light scattering, and can be i =1

used to fit the line-shape and intensity of the Fano resonance that measured in the experiment. As shown in Figure 3b, there is an excellent agreement between the experimental recorded Fano resonance and the fitted spectrum that based on the calculation of our coupled oscillator model. At this moment, all of the parameters for our calculation model, such as ai, ωi, γi, etc., can be obtained from the fitted line-shape and intensity of the Fano resonance (see Supplementary Table S1). If the coupling constants g1 and g2 equal zero, the oscillation intensity for each of the free oscillator 2

ai can be descripted as , by which we calculated the MoS2 A exciton 2 −ω + iγ iω + ωi2 absorption and its corresponding neutral exciton and trion contributions as Figure 3c. The gate-dependent scattering and absorption spectra of the sample under gate voltages of -6V, -2V, 2V and 6V were plotted in Supporting Information (see Figure S5).


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Figure 3. (a) Experimental measured MoS2 A exciton intensity in the energy range of 1.78 eV to 1.9 eV for the gate voltage changed from -8 V to +8 V. Neutral exciton (green line) and trion (orange line) that contribute to A exciton (yellow line) are fitted in the Lorentzian shape.44 The solid arrows represent the trend of the energy evolution of the neutral exciton and trion, respectively. (b) Measured (solid line) and calculated (dashed line) scattering spectra of Fano resonance in the range of 1.78eV to 1.95 eV under the same gate voltage as (a). (c) The calculated MoS2 A exciton intensity and its corresponding neutral exciton and trion contributions.

In order to get a detailed comparison between the experimental and calculation results, the photon energy and spectral intensity of the neutral exciton and trion under different gate voltages are extracted respectively from Figure 3a and 3c and plotted in Figure 4, where we can see more clearly that as the applied voltage changed from -8V to +8V, the photon energy of neutral exciton increased from 1.86 eV to 1.89 eV, 12 ACS Paragon Plus Environment

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while the energy of trion keeps at ~1.84 eV (Figure 4a). For the spectral intensity, both MoS2 A exciton and neutral exciton decrease, while trion approximately preserves its spectral weight (Figure 4b). The calculated results from our three-oscillator model show an excellent agreement with the experimental data.

Figure 4. (a,b) Resonance energies (a) and intensity (b) of the MoS2 A exciton, neutral exciton and trion that extracted from Figure 3a and 3c. The calculation results show an excellent agreement with experimental measurements.

In comparison with the previous two-oscillator model45 that described exciton-plasmon coupling, we consider the contribution of the MoS2 trion to the calculation, which makes our three-oscillator model more precisely to describe the interaction between the MoS2 excitons and Au LSP. This excellent agreement further confirms our calculation model with the fitted parameters is more effective to describe this gate-dependent Fano resonance, and can be used to explore the physics insight of this MoS2 exciton-plasmon coupling.


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In order to exploit the switch time of our single nanoparticle plasmonic modulator, we first measured the electric response of the MoS2 monolayers. As illustrated in Figure 1a, the top and bottom Au electrodes form a plate capacitor, where the MoS2 monolayers can be effectively doped by applying the back-gate bias. As shown in Figure 5a, a fast voltage pulse train (+8V) was applied to the modulator with period of 1 ms and 50% duty cycle, and the oscilloscope was used to monitor the voltage variation. The response time of this MoS2-loaded capacitor was estimated as ~50 ns by extracting the rise and decay regions as plotted in Figure 5b and Figure 5c, respectively, which has the same order of magnitude as the previous reported works.46-47 A negative electrical pulse train (-8V) was also applied and measured (see Figure S6), which shows the same electric response for our modulator. To theoretical estimate the rise and decay time of the modulator, the back gate was modeled as a parallel plate capacitor because the size of electrode is much larger than the thickness of SiO2 layer. 18 The rise or decay time can be calculated using the expression τ =RC, where C=1.15×10-11 F is the capacitance between the electrode and the back gate (C=ε0εrS/d; εr=3.9; S=100*100µm2; d=30 nm), R is resistance. Because the resistance of Au is much smaller than Si substrate, R can approximately equal to the resistance of Si as R=3kΩ (R=ρL/Ssi; ρ= 3 Ω∗cm; L=1mm; S=1*1cm2). Therefore, the calculated rise or decay time was 34.5ns, which has a good agreement with experimental results. We further exploited the electro-optic response time of our modulator by recording the time-resolved reflectance of the MoS2 monolayers around the A exciton resonance 14 ACS Paragon Plus Environment

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with a series of squared electrical voltage pulses in milliseconds. The experimental setup is illustrated in Figure S7. A ‘trigger’ was implemented by applying an 8V-high and 700ms-wide pulse train to detect the optical response of the device, as shown in Figure 5d. The exposure time of the detection CCD camera (Acton SP2500, Princeton Instruments Co.) is set at 200 ms, which is the limit of the spectrometer real-time sampling rate for the valid signal detection. An obvious reflectance switching was observed as Figure 5e. And the electro-optic switch time of our device can be estimated less than 200 ms. In fact, the response time of our modulator should be much faster than 200 ms, because the measured timescale is seriously limited by the integration time of the camera for the signal processing. The plasmon scattering from the nanostructure is directly related with the dielectric permittivity of the MoS2 monolayers, which can be effectively tuned by the back-gate bias, thus we believe the practical switch time should be at the nanosecond scale as shown in Figure 5b and 5c.

Figure 5. (a) The measured voltage variation of the device by applying a fast pulse train (+8V) with period of 1 ms and 50% duty cycle. (b) Rise and (c) decay region of the electric response of MoS2 monolayers, which shows the response time is about 50 15 ACS Paragon Plus Environment

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ns. (d) The 8V-high and 700 ms-wide electrical voltage pulse, which was used as a ‘trigger’ to tune the optical response of the MoS2 monolayers. (e) The time-resolved reflectance of our modulator, which indicates the device switch time is less than 200 ms. With the understanding of this gate-dependent exciton-plasmon coupling, we fabricated a two-dimensional display device by patterning the single Au nanodisks as an array on the MoS2 monolayers. Figure 6a-c are SEM images of our electro-optic modulator with different zoom-in scales. The Au nanodisks with radius of 60 nm and period of 1 µm (as the image pixel size) were deposited as a rectangular array on the MoS2 monolayers, where a portion of the MoS2 was removed by the reactive ion etching (RIE), showing a heptamer pattern as Figure 6b. The detail information about the fabrication process of the heptamer reversible display device is shown in Figure S8. Inside of this heptamer pattern, the isolated Au nanodisks and MoS2 cannot be directly modulated by the external gate voltage. Under the incident light illumination, each of the Au plasmon scattering was homogeneously recorded by the dark-field microscope with a 660 nm bandpass filter placed at the collection optical path (more details can be found in the Methods). When the gate voltage is changed to -8V, the coupling strength between the MoS2 A exciton and Au plasmon increases, and results in a strong Fano resonance at wavelength of ~660 nm, which weakens the scattering of Au nanodisks that fabricated on the surrounding MoS2 monolayers, and displays the heptamer pattern as shown in Figure 6d. When the gate voltage is decreased to zero, the heptamer pattern disappears in the background as shown in Figure 6e. For the positive gate bias as +8V, an inverse control of heptamer pattern display by 16 ACS Paragon Plus Environment

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subtracting the background signal (the intensity of inside heptamer) is demonstrated as Figure 6f. By plotting the spatial distribution of scattering intensity along the nanodisk array, the quantitative modulation of the plasmon scattering intensity are indicated as Figure 6 g-i, where the far-field scattering light of the single particle can be clearly distinguished, and the full width at half maximum (FWHM) of the scattering beam width can be calculated as 370 nm that approaching the optical diffraction limit. This reversible display device is different from the traditional electro-optic modulator, because our gate-voltage control is achieved at a single nanoparticle level (~120 nm) with an ultra-high sensitivity, which can be explained as the reason of directly coupling between the single Au plasmon dipole and the MoS2 A exciton. The strong Fano resonance that generated from this exciton-plasmon coupling is the key for the device tuning. The reversible heptamer pattern display in the work realized an image pixel size of 1 µm, which breaks through the resolution bottleneck of the state-of-the-art display device, and benefits a more sensitive and faster electro-optic modulator prototype at nanoscale. People can further achieve a subwavelength resolution display with the pixel size at λLSP/2 based on our single nanodisk modulator configuration in theory.


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Figure 6. (a) SEM image of the fabricated electro-optic display device with Au nanodisks patterned on the MoS2 monolayers, the scale bar is 10 µm. (b) and (c) the magnified SEM image to show a heptamer pattern with a portion of the MoS2 removed from the substrate. The Au nanodisks and MoS2 inside of the heptamer pattern are isolated, and can hardly be tuned by the gate voltage. The scale bar: 3 µm (b) and 1 µm (c). (d-f) The far-field scattering images of our display device under different gate voltages. (d) as Vg=-8V, the heptamer appears and become a convex 18 ACS Paragon Plus Environment

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image; (e) as Vg=0V, the heptamer pattern is invisible and hided in the background; (f) as Vg=+8V, the heptamer pattern turned to be a concave one with the background intensity subtracted. (g-i) The corresponding scattering intensities along the lines that marked on (d-f) to show the contrast degree of our display device.

CONCLUSIONS In summary, we realized gate-dependent electro-optic modulator with single Au nanodisk that fabricated on the MoS2 monolayers. The plasmon-exciton coupling in this Au/MoS2 hybrid nanostructure generates an excitonic Fano resonance which can be effectively tuned by the applied gate voltage. This electro-optic modulation was explained and calculated by our coupled three-oscillator model, which shows an excellent agreement between the experimental measurements and the calculated results. By controlling the strength of the excitonic Fano resonance at single particle level, a reversible and ultra-sensitive optical display device that based on this nanoscale modulator was successfully demonstrated. Our proposed single nanoparticle modulator configuration provides an effect way to actively manipulate exciton-plasmon interaction, which offers a possible solution for the ultrathin and nanoscale electro-optic device in the future.

MATERIALS AND METHODS

Optical Measurement. The Raman, reflection and PL spectra were measured by a home-built optical microscope equipped with a 100× objective lens (MPlanFL, Olympus Co.). The white light source with fiber illumination (MI-150, Dolan-Jenner 19 ACS Paragon Plus Environment

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Co.) was focused onto the back focal plane of the objective for the reflection spectrum measurement. The surface plasmon resonance and reflection spectra of the Au/MoS2 hybrid structure were collected by the spectrometer (iHR550, Horiba Co.). Commonly, Fano resonance in nanostructures was characterized by using white light illumination and detected by the scattering light. The scattering spectrum of the sample was measured by the commercial dark-field imaging system (HIS v3, CytoViva Co.), and far-field scattering images shown in Figure 6 were obtained by the dark-field optical spectra mapping with a 660 nm bandpass filter (FB660-10, Thorlabs Co.) placed in the detection optical path. The Au electrode is far away from the sample area, and the reflection from the surface of the Au electrode is filtered out by the slit of the spectrometer.

Numerical Simulations. Full-field electromagnetic wave simulations were performed using the Finite-Difference Time-Domain Method solver (FDTD solutions, Lumerical). The investigated structure was simulated using perfectly matched layers along all directions. Total-Field Scattering-Filed source was launched and illuminated the structure along the -z direction. In the simulations, we used Palik data for the Au and Si complex refractive index. The dielectric permittivity of MoS2 monolayers was extracted by parametrizing experimental data into a band and exciton transition (Brunaur-Emmett-Teller) model as reported in previous works.48

Acknowledgement 20 ACS Paragon Plus Environment

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This work is supported by the National Key Research and Development Program of China (grant no. 2017YFA0206000), National Basic Research Program of China (grant no. 2015CB932403, 2017YFA0205700), National Science Foundation of China (grant nos. 61422501, 11674012, 11374023, 61176120, 61378059 and 61521004), and Foundation for the Author of National Excellent Doctoral Dissertation of PR China (grant no. 201420), National Program for Support of Top-notch Young Professionals.

Supporting Information Available: Figure S1: SEM image of Au nanodisk with radius of 60 nm that fabricated on the MoS2 monolayers. Figure S2: The contact resistance between the MoS2 monolayers and fabricated electrodes. Figure S3: The experimental and simulation scattering spectra of MoS2-Au hybrid structure with different sized Au nanodisks. Figure S4: The variation of reflectivity and scattering dip as a function of the applied gate voltages. Figure S5: The gate-dependent scattering and absorption spectra of the sample under gate voltages of -6V, -2V, 2V and 6V. Figure S6: The measured response time of single plasmonic nanoparticle modulator with a negative voltage pulse train (-8V) applied. Figure S7: The schematic illustration of the home-built optical system to measure time-resolved reflectance spectra. Figure S8: Schematic flowchart illustrating the fabrication process of the heptamer reversible display device. Figure S9: The U-shaped electro-optic display device and its far-field emission. Figure S10: The curves of the direct multiplication of the MoS2 reflectivity at different gate voltages in Figure 2 (a,b) and the Au nanoparticle scattering intensity in Figure 1 (c). Table S1: The detailed parameter values for the oscillator model calculation.

REFERENCES 21 ACS Paragon Plus Environment

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

1.

Page 22 of 27

Wang, Q. H.; Kalantar-Zadeh, K.; Kis, A.; Coleman, J. N.; Strano, M. S.,

Electronics

and

Optoelectronics

of

Two-Dimensional

Transition

Metal

Dichalcogenides. Nat. Nanotechnol. 2012, 7, 699-712. 2.

Liu, X.; Galfsky, T.; Sun, Z.; Xia, F.; Lin, E.-c.; Lee, Y.-H.; Kéna-Cohen, S.;

Menon, V. M., Strong Light-Matter Coupling in Two-Dimensional Atomic Crystals.

Nat. Photonics 2015, 9, 30-34. 3.

Komsa, H.-P.; Kotakoski, J.; Kurasch, S.; Lehtinen, O.; Kaiser, U.;

Krasheninnikov, A. V., Two-Dimensional Transition Metal Dichalcogenides under Electron Irradiation: Defect Production and Doping. Phys. Rev. Lett. 2012, 109, 035503. 4.

Kim, S.; Konar, A.; Hwang, W.-S.; Lee, J. H.; Lee, J.; Yang, J.; Jung, C.; Kim,

H.; Yoo, J.-B.; Choi, J.-Y., High-Mobility and Low-Power Thin-Film Transistors Based on Multilayer MoS2 Crystals. Nat. Commun. 2012, 3, 1011. 5.

Barnes, W. L.; Dereux, A.; Ebbesen, T. W., Surface Plasmon Subwavelength

Optics. Nature 2003, 424, 824-830. 6.

Kim, S.; Jin, J.; Kim, Y.-J.; Park, I.-Y.; Kim, Y.; Kim, S.-W., High-Harmonic

Generation by Resonant Plasmon Field Enhancement. Nature 2008, 453, 757-760. 7.

Becker, J.; Zins, I.; Jakab, A.; Khalavka, Y.; Schubert, O.; Sönnichsen, C.,

Plasmonic Focusing Reduces Ensemble Linewidth of Silver-Coated Gold Nanorods.

Nano Lett. 2008, 8, 1719-1723. 8.

Gramotnev, D. K.; Bozhevolnyi, S. I., Plasmonics Beyond the Diffraction Limit.

Nat. Photonics 2010, 4, 83-91. 9.

Temnov, V. V.; Armelles, G.; Woggon, U.; Guzatov, D.; Cebollada, A.;

Garcia-Martin, A.; Garcia-Martin, J.-M.; Thomay, T.; Leitenstorfer, A.; Bratschitsch, R., Active Magneto-Plasmonics in Hybrid Metal-Ferromagnet Structures. Nat.

Photonics 2010, 4, 107-111. 10. Khatua, S.; Chang, W.-S.; Swanglap, P.; Olson, J.; Link, S., Active Modulation of Nanorod Plasmons. Nano Lett. 2011, 11, 3797-3802.


Page 23 of 27

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

11. Clavero,

C.,

Plasmon-Induced

Hot-Electron

Generation

at

Nanoparticle/Metal-Oxide Interfaces for Photovoltaic and Photocatalytic Devices.

Nat. Photonics 2014, 8, 95-103. 12. Luk'yanchuk, B.; Zheludev, N. I.; Maier, S. A.; Halas, N. J.; Nordlander, P.; Giessen, H.; Chong, C. T., The Fano Resonance in Plasmonic Nanostructures and Metamaterials. Nat. Mater. 2010, 9, 707-715. 13. Wu, C.; Khanikaev, A. B.; Adato, R.; Arju, N.; Yanik, A. A.; Altug, H.; Shvets, G., Fano-Resonant Asymmetric Metamaterials for Ultrasensitive Spectroscopy and Identification of Molecular Monolayers. Nat. Mater. 2012, 11, 69-75. 14. Emani, N. K.; Chung, T.-F.; Kildishev, A. V.; Shalaev, V. M.; Chen, Y. P.; Boltasseva,

A.,

Electrical

Modulation

of

Fano

Resonance

in

Plasmonic

Nanostructures Using Graphene. Nano Lett. 2013, 14, 78-82. 15. Zhang, S.; Genov, D. A.; Wang, Y.; Liu, M.; Zhang, X., Plasmon-Induced Transparency in Metamaterials. Phys. Rev. Lett. 2008, 101, 047401. 16. Fofang, N. T.; Park, T.-H.; Neumann, O.; Mirin, N. A.; Nordlander, P.; Halas, N. J., Plexcitonic Nanoparticles: Plasmon-Exciton Coupling in Nanoshell−J-aggregate Complexes. Nano Lett. 2008, 8, 3481-3487. 17. Nan, F.; Zhang, Y.-F.; Li, X.; Zhang, X.-T.; Li, H.; Zhang, X.; Jiang, R.; Wang, J.; Zhang, W.; Zhou, L., Unusual and Tunable One-Photon Nonlinearity in Gold-Dye Plexcitonic Fano Systems. Nano Lett. 2015, 15, 2705-2710. 18. Radisavljevic, B.; Radenovic, A.; Brivio, J.; Giacometti, i. V.; Kis, A., Single-Layer MoS2 Transistors. Nat. Nanotechnol. 2011, 6, 147-150. 19. Wang, H.; Zhang, C.; Chan, W.; Tiwari, S.; Rana, F., Ultrafast Response of Monolayer Molybdenum Disulfide Photodetectors. Nat. Commun. 2015, 6, 8831. 20. Eginligil, M.; Cao, B.; Wang, Z.; Shen, X.; Cong, C.; Shang, J.; Soci, C.; Yu, T., Dichroic Spin-Valley Photocurrent in Monolayer Molybdenum Disulphide. Nat.

Commun. 2015, 6,7636. 21. Mak, K. F.; Lee, C.; Hone, J.; Shan, J.; Heinz, T. F., Atomically Thin MoS2: A New Direct-Gap Semiconductor. Phys. Rev. Lett. 2010, 105, 136805. 23 ACS Paragon Plus Environment

ACS Nano

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 27

22. Tsai, M.-L.; Su, S.-H.; Chang, J.-K.; Tsai, D.-S.; Chen, C.-H.; Wu, C.-I.; Li, L.-J.; Chen, L.-J.; He, J.-H., Monolayer MoS2 Heterojunction Solar Cells. ACS Nano

2014, 8, 8317-8322. 23. Li, Z.; Xiao, Y.; Gong, Y.; Wang, Z.; Kang, Y.; Zu, S.; Ajayan, P. M.; Nordlander, P.; Fang, Z., Active Light Control of the MoS2 Monolayer Exciton Binding Energy. ACS Nano 2015, 9, 10158-10164. 24. Lee, H. S.; Luong, D. H.; Kim, M. S.; Jin, Y.; Kim, H.; Yun, S.; Lee, Y. H., Reconfigurable Exciton-Plasmon Interconversion for Nanophotonic Circuits. Nat.

Commun. 2016, 7,13663. 25. Splendiani, A.; Sun, L.; Zhang, Y.; Li, T.; Kim, J.; Chim, C.-Y.; Galli, G.; Wang, F., Emerging Photoluminescence in Monolayer MoS2. Nano Lett. 2010, 10, 1271-1275. 26. Zeng, H.; Dai, J.; Yao, W.; Xiao, D.; Cui, X., Valley Polarization in MoS2 Monolayers by Optical Pumping. Nat. Nanotechnol. 2012, 7, 490-493. 27. Kang, Y.; Najmaei, S.; Liu, Z.; Bao, Y.; Wang, Y.; Zhu, X.; Halas, N. J.; Nordlander, P.; Ajayan, P. M.; Lou, J., Plasmonic Hot Electron Induced Structural Phase Transition in a MoS2 Monolayer. Adv. Mater. 2014, 26, 6467-6471. 28. Castellanos‐Gomez, A.; van Leeuwen, R.; Buscema, M.; van der Zant, H. S.; Steele, G. A.; Venstra, W. J., Single-Layer MoS2 Mechanical Resonators. Adv. Mater.

2013, 25, 6719-6723. 29. Kibsgaard, J.; Chen, Z.; Reinecke, B. N.; Jaramillo, T. F., Engineering the Surface Structure of MoS2 to Preferentially Expose Active Edge Sites for Electrocatalysis. Nat. Mater. 2012, 11, 963-969. 30. Liu, C.-H.; Kim, I. S.; Lauhon, L. J., Optical Control of Mechanical Mode-Coupling within a MoS2 Resonator in the Strong-Coupling Regime. Nano Lett.

2015, 15, 6727-6731. 31. Mak, K. F.; He, K.; Shan, J.; Heinz, T. F., Control of Valley Polarization in Monolayer MoS2 by Optical Helicity. Nat. Nanotechnol. 2012, 7, 494-498.


Page 25 of 27

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Nano

32. Radisavljevic, B.; Kis, A., Mobility Engineering and a Metal-Insulator Transition in Monolayer MoS2. Nat. Mater. 2013, 12, 815-820. 33. Radisavljevic, B.; Whitwick, M. B.; Kis, A., Integrated Circuits and Logic Operations Based on Single-Layer MoS2. ACS Nano 2011, 5, 9934-9938. 34. Sundaram, R.; Engel, M.; Lombardo, A.; Krupke, R.; Ferrari, A.; Avouris, P.; Steiner, M., Electroluminescence in Single Layer MoS2. Nano Lett. 2013, 13, 1416-1421. 35. Hong, T.; Chamlagain, B.; Hu, S.; Weiss, S. M.; Zhou, Z.; Xu, Y.-Q., Plasmonic Hot Electron Induced Photocurrent Response at MoS2-Metal Junctions. ACS Nano

2015, 9, 5357-5363. 36. Liu, W.; Lee, B.; Naylor, C. H.; Ee, H.-S.; Park, J.; Johnson, A. C.; Agarwal, R., Strong Exciton-Plasmon Coupling in MoS2 Coupled with Plasmonic Lattice. Nano

Lett. 2016, 16, 1262-1269. 37. Zheng, D.; Zhang, S.; Deng, Q.; Kang, M.; Nordlander, P.; Xu, H., Manipulating Coherent Plasmon-Exciton Interaction in Single Silver Nanorod on Monolayer WSe2.

Nano Lett. 2017,17, 3809–3814. 38. Butun, S.; Tongay, S.; Aydin, K., Enhanced Light Emission from Large-Area Monolayer MoS2 Using Plasmonic Nanodisc Arrays. Nano Lett. 2015, 15, 2700-2704. 39. Li, Z.; Li, Y.; Han, T.; Wang, X.; Yu, Y.; Tay, B.; Liu, Z.; Fang, Z., Tailoring MoS2 Exciton-Plasmon Interaction by Optical Spin-Orbit Coupling. ACS Nano 2017,

11, 1165-1171. 40. Miao, J.; Hu, W.; Jing, Y.; Luo, W.; Liao, L.; Pan, A.; Wu, S.; Cheng, J.; Chen, X.; Lu, W., Surface Plasmon-Enhanced Photodetection in Few Layer MoS2 Phototransistors with Au Nanostructure Arrays. Small 2015, 11, 2392-2398. 41. Lin, J.; Li, H.; Zhang, H.; Chen, W., Plasmonic Enhancement of Photocurrent in MoS2 Field-Effect-Transistor. Appl. Phys. Lett. 2013, 102, 203109. 42. Mulpur, P.; Yadavilli, MoS2/WS2/BN-Silver

S.; Rao, A. M.; Kamisetti, V.; Podila, R.,

Thin-Film

Hybrid

Architectures

Displaying

Enhanced


ACS Nano

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 26 of 27

Fluorescence via Surface Plasmon Coupled Emission for Sensing Applications. ACS

Sensors 2016, 1, 826-833. 43. Mak, K. F.; He, K.; Lee, C.; Lee, G. H.; Hone, J.; Heinz, T. F.; Shan, J., Tightly Bound Trions in Monolayer MoS2. Nat. Mater. 2013, 12, 207-211. 44. Chernikov, A.; van der Zande, A. M.; Hill, H. M.; Rigosi, A. F.; Velauthapillai, A.; Hone, J.; Heinz, T. F., Electrical Tuning of Exciton Binding Energies in Monolayer WS2. Phys. Rev. Lett. 2015, 115, 126802. 45. Abid, I.; Bohloul, A.; Najmaei, S.; Avendano, C.; Liu, H.-L.; Péchou, R.; Mlayah, A.; Lou, J., Resonant Surface Plasmon-Exciton Interaction in Hybrid MoSe2@ Au Nanostructures. Nanoscale 2016, 8, 8151-8159. 46. Krasnozhon, D.; Lembke, D.; Nyffeler, C.; Leblebici, Y.; Kis, A., MoS2 Transistors Operating at Gigahertz Frequencies. Nano Lett. 2014, 14, 5905-5911. 47. Zhou, Y.; Liu, W.; Huang, X.; Zhang, A.; Zhang, Y.; Wang, Z. L., Theoretical Study on Two-Dimensional MoS2 Piezoelectric Nanogenerators. Nano Res. 2016, 9, 800-807. 48. Zu, S.; Li, B.; Gong, Y.; Li, Z.; Ajayan, P. M.; Fang, Z., Active Control of Plasmon-Exciton Coupling in MoS2-Ag Hybrid Nanostructures. Adv. Opt.

Mater.2016, 4, 1463-1469.


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