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Significant enhancement of infrared transmittance by the presence of a graphene layer on a plasmonic metasurface (PLM) has been demonstrated. PLMs with different configurations were fabricated, and their transmittance with and without graphene was compared. Selective enhancement by graphene occurred at the plasmon resonance wavelength. The degree o...
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This paper proposes a realization of an easy to manufacture graphene device with a low-cost and solvent-free procedure. It is obtained by depositing few layer graphene in a gap between to electrodes in a microstrip-like circuit. The device is characterized in DC at room temperature, and the results show a satisfactory stability of its electrical re...
Citations
... Additionally, graphene can be fabricated at a low cost using nontoxic processes. Various graphene-based photodetectors have been developed using performance enhancement methods such as asymmetric electrodes [20,28,29], plasmonic metasurfaces [30][31][32][33][34], p-n junctions [35][36][37], Schottky junctions [38][39][40], tunneling currents between parallel graphene sheets [41], nanoribbons [42,43], carrier multiplication [44,45], bolometers [46,47], photonic cavities [48][49][50], and photogating. Among these, the photogating is the most promising technique in terms of improving the photodetectors performance, which cannot be achieved using conventional methods used to increase absorption efficiency. ...
This study demonstrates that graphene can boost the performance of type-II superlattice (T2SL) infrared photodetectors. The devices were fabricated by simply forming graphene transistors or graphene diodes on InAs/GaInSb T2SLs, in contrast to recent structures that are grown using complex crystal growth and bandgap engineering techniques. The long wavelength infrared performance of the T2SL was improved by a factor of 5.5, and the T2SL-based graphene diodes exhibited the lowest noise equivalent power value of 4.09 pW/Hz½ while the T2SL diodes without the graphene exhibited that of 26.7 pW/Hz½. These findings indicate the potential to improve infrared image sensor performance by incorporating graphene.
... Additionally, graphene can be fabricated at a low cost using nontoxic processes. Various graphene-based photodetectors have been developed using performance enhancement methods such as asymmetric electrodes [20,28,29], plasmonic metasurfaces [30][31][32][33][34], p-n junctions [35][36][37], Schottky junctions [38][39][40], tunneling currents between parallel graphene sheets [41], nanoribbons [42,43], carrier multiplication [44,45], bolometers [46,47], photonic cavities [48][49][50], and photogating. Among these, the photogating is the most promising technique in terms of improving the photodetectors performance, which cannot be achieved using conventional methods used to increase absorption efficiency. ...
This study demonstrates that graphene can boost the performance of type-II superlattice (T2SL) infrared photodetectors. The devices were fabricated by simply forming graphene transistors or graphene diodes on InAs/GaInSb T2SLs, in contrast to recent structures that are grown using complex crystal growth and bandgap engineering techniques. The long wavelength infrared performance of the T2SL was improved by a factor of 5.5, and the T2SL-based graphene diodes exhibited the lowest noise equivalent power value of 4.09 pW/Hz½ while the T2SL diodes without the graphene exhibited that of 26.7 pW/Hz½. These findings indicate the potential to improve infrared image sensor performance by incorporating graphene.
... An alternate approach is to combine graphene with other plasmonic materials to form hybrid plasmonic structures, through near-field coupling [30][31][32][33]. Taking this approach one step further, the plasmonic nanoantenna can also be precision designed and patterned to form sub-wavelength arrays of quasi-2D metastructures or metasurfaces [34][35][36][37]. ...
We integrated graphene with asymmetric metal metasurfaces and optimised the geometry dependent photoresponse towards optoelectronic molecular sensor devices. Through careful tuning and characterisation, combining finite-difference time-domain simulations, electron-beam lithography-based nanofabrication, and micro-Fourier transform infrared spectroscopy, we achieved precise control over the mid-infrared peak response wavelengths, transmittance, and reflectance. Our methods enabled simple, reproducible and targeted mid-infrared molecular sensing over a wide range of geometrical parameters. With ultimate minimization potential down to atomic thicknesses and a diverse range of complimentary nanomaterial combinations, we anticipate a high impact potential of these technologies for environmental monitoring, threat detection, and point of care diagnostics.
... 9 In particular, graphene is applicable to photodetectors, which require a broadband photoresponse from the ultraviolet to terahertz regions, high-speed operation, and low fabrication costs. [10][11][12] Numerous methods, including those employing asymmetric electrodes, 13 plasmonics, [14][15][16][17] p − n junctions, 18,19 bolometers, 20,21 photonic cavities, [22][23][24] waveguides, [25][26][27] Schottky junctions, [28][29][30] and photogating, [31][32][33][34][35][36][37][38][39][40] have been proposed to enhance the response of graphene-based photodetectors. Among them, photogating is the most promising approach because it can realize the highest performance. ...
... In terms of the second drawback, plasmonic metasurfaces (PMs) are a promising approach for enhancing the optical absorption of graphene at surface plasmon resonance (SPR) wavelengths [27]. Many methods have been proposed to enhance the photoresponsivity of graphene-based photodetectors using PMs, such as nanoantennas or meta-atoms [28][29][30][31][32][33][34] and metalinsulator-metal-based (MIM) metamaterial structures [35]. ...
... However, we considered C P of up to 1.5 eV considering previous studies [47,48] to determine the theoretical property. Figures 6(a)-6(c) demonstrate that the peak absorption wavelength shifted to shorter wavelengths with increasing C P , independent of the p and w values, because the LSPR is produced in the vicinity of graphene, as shown in Fig. 5(a), where a change in the C P of graphene can modify the LSPR wavelength [29,49]. Figure 6(d) shows the relationship between C P and the peak absorption wavelength. ...
Graphene has promising applications for novel optoelectronic devices. However, graphene-based photodetectors have two major drawbacks that need attention. The first is how to preserve graphene’s original high carrier mobility, and the second is how to enhance graphene’s absorption to improve its performance. Hexagonal boron nitride (hBN)/graphene van der Waals (vdW) heterostructure-based plasmonic metasurfaces (PMs) are proposed for wavelength-selective infrared (IR) photodetectors. hBN preserves graphene’s high carrier mobility, and PMs enhance graphene’s absorption. Numerical calculations demonstrate sufficient wavelength-selective absorption in the broadband IR wavelength range. Such optical properties are realized by coupling the localized surface plasmon resonance (SPR) of PMs and propagating SPR of graphene. The proposed vdW heterostructure-based PMs could be used for high-performance multi-spectral IR photodetectors.
... An important issue limiting the practical application of graphene is its minimal optical absorbance (2.3% [3]). Previously proposed approaches for increasing its responsivity have employed dissimilar electrodes [5,7], p-n junctions [8,9], bolometers, [10] thermopiles [11], optical cavities [12,13], plasmonic resonance devices [14][15][16], dual graphene sheets with tunneling morphologies [17], nanoribbons [18], and photogates [19][20][21][22][23][24][25][26][27][28]. The use of photogates may be the most viable solution, because this technique yields the largest increase in responsivity, as well as a higher quantum efficiency [24]. ...
We employ turbostratic stacked chemical vapor deposition (CVD) graphene for a mid-wavelength infrared (MWIR) photodetector using the photogating effect. Turbostratic stacked CVD graphene was fabricated by multiple transfer processes. Graphene field effect transistor-based MWIR photodetectors were developed using an InSb substrate. The effect of the three layers of turbostratic stacked graphene enhanced both the field-effect mobility and MWIR response by approximately three times, compared to that of a conventional single-layer graphene photodetector in vacuum at 77 K. Our results may contribute to the realization of low-cost, mass-producible, high-responsivity graphene-based infrared sensors.
... However, graphene has a low absorbance (~2.3%). Various methods have been proposed to enhance its responsivity, including those based on hetero-electrodes 9, 10 , optical cavities 11,12 , plasmonic structures [13][14][15][16][17] , nano-patterned graphene for graphene plasmons [18][19][20][21][22] , the bolometric effect 23 , PN junctions 24 , quantum dots [25][26][27] , heterostructures with semidonductors [28][29][30][31][32] , and photogating [33][34][35][36][37] . Among them, photogating is the most effective method for achieving ultra-high responsivity, which cannot be achieved using conventional technologies. ...
... As discussed in Section 2.2, the optical conductivity of graphene can be tuned by applying a voltage, such that the modulation of SPP wavelengths can be achieved using metallic nanostructures. Typically, this modulation is associated with the integration of graphene with metasurfaces [120][121][122][123][124][125][126][127], split rings [122,128,129] or other metamaterials [130][131][132][133][134] or with metallic nanoparticles [135,136]. Figure 8 shows a typical example of the modulation of the device reflection and the reflection phase by adjusting the extent of doping of the graphene. ...
Surface plasmon polaritons (SPPs) can be generated in graphene at frequencies in the mid-infrared to terahertz range, which is not possible using conventional plasmonic materials such as noble metals. Moreover, the lifetime and confinement volume of such SPPs are much longer and smaller, respectively, than those in metals. For these reasons, graphene plasmonics has potential applications in novel plasmonic sensors and various concepts have been proposed. This review paper examines the potential of such graphene plasmonics with regard to the development of novel high-performance sensors. The theoretical background is summarized and the intrinsic nature of graphene plasmons, interactions between graphene and SPPs induced by metallic nanostructures and the electrical control of SPPs by adjusting the Fermi level of graphene are discussed. Subsequently, the development of optical sensors, biological sensors and important components such as absorbers/emitters and reconfigurable optical mirrors for use in new sensor systems are reviewed. Finally, future challenges related to the fabrication of graphene-based devices as well as various advanced optical devices incorporating other two-dimensional materials are examined. This review is intended to assist researchers in both industry and academia in the design and development of novel sensors based on graphene plasmonics.
... However, since graphene has a low light-absorption value of ∼2.3%, 21 a method is required to enhance the responsivity, such as the use of plasmonic antennas, 22 optical waveguides, 23 or photocarrier injection. 24 We have previously investigated various techniques for this purpose, including the use of p-n junctions, 25 plasmonic metamaterial absorbers, [26][27][28] and the photogating effect. [29][30][31][32][33][34] Here, we report a detailed mechanism for the photogating effect that significantly improves the responsivity of graphene photodetectors operating in the MWIR spectral band. ...
... Unfortunately, graphene shows low responsivity, as its optical absorbance is just 2.3%, 3) and so the real-world applicability of this material will require improvements to this property. Dissimilar electrodes, 5,7) pn-junctions, 8,9) bolometers, 10) thermopiles, 11) optical cavities, 12,13) plasmonic resonance, [14][15][16] tunneling structures based on dual graphene sheets, 17) nanoribbons, 18) and photogating [19][20][21][22][23][24][25] have all been assessed as means of improving the responsivity of graphene-based photodetectors. Among these, photogating perhaps has the most potential, since this technique can improve the responsivity to a degree that is not possible with standard approaches, including increasing the quantum efficiency. ...
High-responsivity graphene photodetectors were fabricated using turbostratic stacked graphene, which provided enhanced photogating. Photogating is a promising means of increasing the responsivity of graphene photodetectors, and this effect is proportional to carrier mobility. Turbostratic stacked graphene exhibits higher carrier mobility than conventional monolayer graphene because it has the same band structure as monolayer graphene while preventing scattering by the underlying SiO 2 layer. The photoresponse of these devices at a wavelength of 642 nm was approximately twice that obtained for a conventional monolayer graphene photodetector. The results reported show the feasibility of producing high-responsivity graphene-based photodetectors using a simple fabrication technique.
