Plasmonic Photodetectors Research Articles

High-performance single SiC nanocable-based plasmonic photodetectors for ultraviolet communication systems

High-performance single SiC nanocable-based plasmonic photodetectors for ultraviolet communication systems

Flexible transparent conductors with a percolated Ag nanostructure and its application as efficient self-bias plasmonic photodetector

A percolated silver (Ag) nanostructured-based transparent conductor has been deposited by physical vapor deposition (PVD) technique where lateral growth of Ag has been enhanced by a pre-deposited Ag-TiO2 thin film. This Ag-TiO2 film has embedded Ag nanoparticles (NPs) within TiO2 thin film which is grown in a low temperature (100 °C) solution processed technique. This process includes Li4Ti5O12 (LTO) thin film deposition by a sol–gel method followed by ion-exchange (Li+ → Ag+) process to yield an Ag-TiO2 thin film. The percolated Ag network has appeared as soon film mass-thickness reaches close to 10 nm, resulting in an abrupt drop of electrical resistivity of the film. This percolated Ag nanostructured thin film (10 nm Ag/Ag-TiO2/plastic) has resistivity of ∼50 Ω/□ and an average visual transmittance of >70 % up to 450 nm. In higher wavelength range, transparency gradually reduces, and it reaches to ∼50 % at 600 nm which is mostly due to the plasmon absorption of this film. By utilizing its combined optical transparency and surface plasmon absorption, this film has been used to develop plasmonic hot electron photodetectors where Ag-thin film works as transparent electrode as well as plasmon induced photo-excited hot electron generation. Device has been fabricated on a heavily doped n type Si (n++-Si) with a metal–semiconductor-metal (M−S−M) device geometry. External quantum efficiency (EQE) data reveal that photocurrent of this device is mostly generated in the plasmonic absorption region with a peak detectivity of 2.84 × 1012 Jones at 510 nm under −3V external bias. Besides, the device shows fast response with a response time of ∼25 ms.

High operating temperature HgCdTe coupled cavity plasmonic infrared photodetectors.

Increasing the operating temperature while enhancing detectivity is paramount for the advancement of HgCdTe infrared detectors. In this context, the integration of plasmonic nanostructures emerges as one of the most intriguing avenues, promising breakthroughs in infrared sensing capabilities. Multiphysics TCAD simulations of pin nanostructured focal plane photodetector arrays unveil the potential benefits of submicron absorber thicknesses, that promise detectivities more than twice as large as those provided by conventional 5μm-thick absorbers, besides enabling operating temperatures up to 260 K. Such performance increase is discussed through the combination of numerical simulations and quantum mechanical treatment based on the occupation number formalism, describing the interaction between plasmonic and optical cavity modes responsible for the spectral broadening of the optical response, allowing for good coverage of the entire mid-infrared band (λ∈[3,5]μm).

Tunable mid-infrared photodetector based on graphene plasmons controlled by ferroelectric polarization for micro-spectrometer

Surface plasmonic detectors have the potential to be key components of miniaturized chip-scale spectrometers. Graphene plasmons, which are highly confined and gate-tunable, are suitable for in situ light detection. However, the tuning of graphene plasmonic photodetectors typically relies on the complex and high operating voltage based on traditional dielectric gating technique, which hinders the goal of miniaturized and low-power consumption spectrometers. In this work, we report a tunable mid-infrared (MIR) photodetector by integrating of patterned graphene with non-volatile ferroelectric polarization. The polarized ferroelectric thin film provides an ultra-high surface electric field, allowing the Fermi energy of the graphene to be manipulated to the desired level, thereby exciting the surface plasmon polaritons effect, which is highly dependent on the free carrier density of the material. By exciting intrinsic graphene plasmons, the light transmittance of graphene is greatly enhanced, which improves the photoelectric conversion efficiency of the device. Additionally, the electric field on the surface of graphene enhanced by the graphene plasmons accelerates the carrier transfer efficiency. Therefore, the responsivity of the device is greatly improved. Our simulations show that the detectors have a tunable resonant spectral response of 9–14 μm by reconstructing the ferroelectric domain and exhibit a high responsivity to 5.67 × 105 A W−1 at room temperature. Furthermore, we also demonstrate the conceptual design of photodetector could be used for MIR micro-spectrometer application.

Aluminum-Based Plasmonic Photodetector for Sensing Applications

Plasmonic sensors have great potential for widespread usage. However, the prohibitive cost of noble metals restrains the wider adoption of these devices. The aim of our study is to develop a cost-effective Al-based alternative to common noble metal-based plasmonic detectors. We considered a structure consisting of an n-type doped Si wafer with a shallow p-n junction and an overlying Al grating with a trapezoidal groove profile. The RCWA (rigorous coupled-wave analysis) method was used to numerically calculate the distribution of absorbed light energy in the plasmonic detector layers and to optimize the grating parameters. Based on the simulation results, experimental samples of plasmonic photodetectors with optimal grating parameters (period—633 nm, relief depth—50 nm, groove filling factor—0.36, and thickness of the intermediate Al layer—14 nm) were manufactured, and their properties were studied. For these samples, we obtained a polarization sensitivity value of Ip/Is = 8, an FWHM of the resonance in the photocurrent spectrum ranging from 50 to 100 nm, a sensitivity at the resonance maximum of Iph = 0.04–0.06 A/W, and an angular half-width of photocurrent resonance of Δθ = 5°, which are comparable to noble metal-based analogs. Our results may be used for creating cost-effective high-sensitivity plasmonic sensors.

High-Efficiency and Polarization-Independent Waveguide-Integrated Graphene Plasmonic Photodetectors Operating at 2 μm

High-Efficiency and Polarization-Independent Waveguide-Integrated Graphene Plasmonic Photodetectors Operating at 2 μm

Optimizing geometry and metal-dependent performance of Si-based Schottky plasmonic photodetectors

In this study, different Schottky photodetectors with a plasmonic assist which receives Near-infrared (NIR) light at room temperature were demonstrated. We achieved remarkable detection over a wide range of wavelengths through a comparative study of Schottky plasmonic photodetectors employing Au, Ti, Mo, and Cr as a Schottky metal, a diffusion barrier, an adhesion promoter, and to suppress the formation of intermetallic compounds and plasmonic resonance shifts. The device structure is determined by extensive experimental and modeling results, ensuring a wavelength-specific plasmonic photodetection and a near one-to-one correspondence between incident angles and wavelengths within the NIR region. The combination of different metals in the plasmonic structure efficiently broadened the SPR response, due to the variation of junction barrier height and enhanced interface properties. It exhibited exceptional photocurrent response under room temperature and zero biasing conditions, characterized by high linearity and sensitivity. Light acquisition for longer NIR wavelengths became possible, and applicable in gas sensing, particularly within the vibrational absorption bands of alkane groups. These findings provide valuable design guidelines for optimizing device structures and insights into their application for various scenarios.

Superior Visible Photoelectric Response with Au/Cu2NiSnS4 Core-Shell Nanocrystals.

The incorporation of plasmonic metal nanostructures into semiconducting chalcogenides in the form of core-shell structures provides a promising approach to enhancing the performance of photodetectors. In this study, we combined Au nanoparticles with newly developed copper-based chalcogenides Cu2NiSnS4 (Au/CNTS) to achieve an ultrahigh optoelectronic response in the visible regime. The high-quality Au/CNTS core-shell nanocrystals (NCs) were synthesized by developing a unique colloidal hot-injection method, which allowed for excellent control over sizes, shapes, and elemental compositions. The as-synthesized Au/CNTS hybrid core-shell NCs exhibited enhanced optical absorption, carrier extraction efficiency, and improved photosensing performance owing to the plasmonic-induced resonance energy transfer effect of the Au core. This effect led to a significant increase in the carrier density of the Au/CNTS NCs, resulting in a measured responsivity of 1.2 × 103 AW-1, a specific detectivity of 6.2 × 1011 Jones, and an external quantum efficiency of 3.8 × 105 % at an incident power density of 318.5 μW cm-2. These results enlighten a new era in the development of plasmonic core-shell nanostructure-based visible photodetectors.

Waveguide-Integrated Plasmonic Photodetectors and Activation Function Units With Phase Change Materials

Waveguide-Integrated Plasmonic Photodetectors and Activation Function Units With Phase Change Materials

Wafer‐Scale Fabrication of Graphene‐Based Plasmonic Photodetector with Polarization‐Sensitive, Broadband, and Enhanced Response

AbstractGraphene‐based photodetectors draw tremendous interests for broadband photodetection in optical communications, sensing, and hyperspectral imaging. However, the extremely low light absorption coefficient of graphene posts a great challenge for high‐efficiency photodetection. Although plasmonic nanostructures provide resonant absorption enhancement and impressive responsivity, the current fabrication techniques suffer from being time‐consuming, low‐yield, and potentially high‐cost. In this work, a wafer‐scale graphene‐Au nanogratings (Gra‐Au NGs) plasmonic photodetector array is fabricated via two‐beam holographic lithography, which achieves a photosensitive area of 1 mm2, showing balanced abilities of polarization‐sensitive, broadband, and enhanced photoresponse from visible to near‐infrared regions. The maximum polarization extinction ratio and responsivity of the Gra‐Au NGs photodetector reach 6.65 and 2.95 mA W−1. The surface plasmon resonance of Au NGs and near‐field coupling with graphene render strong electric field confinement and enhanced light absorption, which improve the device photoresponse and polarization sensitivity. The hot electrons generation and transportation models in the Gra‐Au NGs heterojunction are proposed, perfectly matching with the photocurrent mapping and equalized energy band distribution. This work enlightens the wafer‐scale fabrication of graphene‐based plasmonic photodetectors, and it can trigger the advances of free‐space detection, such as remote sensing and satellite communication.

Mid-infrared circular-polarization-sensitive photodetector based on a chiral metasurface with a photothermoelectric effect.

Photothermoelectric conversion in chiral metasurfaces with thermoelectric material provides an effective way to achieve circular polarization recognition. In this paper, we propose a circular-polarization-sensitive photodetector in a mid-infrared region, which is mainly composed of an asymmetric silicon grating, a film of gold (Au), and the thermoelectric B i 2 T e 3 layer. The asymmetric silicon grating with the Au layer achieves high circular dichroism absorption due to a lack of mirror symmetry, which results in a different temperature increasing on the surface of the B i 2 T e 3 layer under right-handed circularly polarized (RCP) and left-handed circularly polarized (LCP) excitation. Then the chiral Seebeck voltage and output power density are obtained, thanks to the thermoelectric effect of B i 2 T e 3. All the works are based on the finite element method, and the simulation results are conducted by the Wave Optics module of COMSOL, which is coupled with the Heat Transfer module and Thermoelectric module of COMSOL. When the incident flux is 1.0W/c m 2, the output power density under RCP (LCP) light reaches 0.96m W/c m 2 (0.01m W/c m 2) at a resonant wavelength, which achieves a high capability of detecting circular polarization. Besides, the proposed structure shows a faster response time than that of other plasmonic photodetectors. Our design provides a novel, to the best of our knowledge, method for chiral imaging, chiral molecular detection, and so on.

Electromechanically reconfigurable plasmonic photodetector with a distinct shift in resonant wavelength

Plasmonic photodetectors have received increasing attention because their detection properties can be designed by tailoring their metal structures on surfaces without using any additional components. Reconfiguration of the plasmonic resonant state in a photodetector is relevant for various applications, including investigating in situ adaptive detection property changes, depending on the situation, and performing single-pixel spectroscopy in geometrically limited regions. However, the spectral responsivity change with conventional reconfiguration methods is relatively small. Here, we propose a plasmonic photodetector that reconfigures its spectral responsivity with electromechanical deformation instead of bias tuning. The photodetector consists of a gold plasmonic grating formed on an n-type silicon cantilever, and the spectral responsivity is reconfigured by electromechanically scanning at an incident angle to the grating on the cantilever. The photodetector exhibits peak shifts in spectral responsivity in a wavelength range from 1250 to 1310 nm after electromechanical reconfiguration. Finally, for potential future applications, we demonstrate near-infrared spectroscopy using the photodetector. This photodetector has the potential to be adopted as a near-infrared spectrometer in industrial silicon imaging systems because its structure enables subbandgap photodetection on silicon by a Schottky junction.

Enhancing Hot Electron Injection in Plasmonic Photodetectors through Roughened Interfaces

Ongoing efforts have been made to improve the photoresponsivity of plasmonic photodetectors. In this work, the photodetectors based on transparent conductive oxide (TCO)/Semiconductor/Metal configuration especially with a roughened interface were investigated numerically, and the effect of the roughness on the injection efficiency of hot electrons was analyzed. The simulated results indicate that a roughened structure alleviates effectively the momentum mismatch of hot electrons at the metal/semiconductor interface due to asymmetry factor, and greatly improves the injection efficiency as well as photoresponsivity. At the incidence wavelength of 1550 nm, the photoresponsivity increased by about 8 times. Meanwhile, the influence on the resonant wavelength shift is negligible where the roughness is nano-scale. Our work provides a valuable guidance for the theoretical and experimental research of plasmonic photodetectors.

On-chip mid-infrared photothermoelectric detectors for full-Stokes detection

On-chip polarimeters are highly desirable for the next-generation ultra-compact optical and optoelectronic systems. Polarization-sensitive photodetectors relying on anisotropic absorption of natural/artificial materials have emerged as a promising candidate for on-chip polarimeters owing to their filterless configurations. However, these photodetectors can only be applied for detection of either linearly or circularly polarized light, not applicable for full-Stokes detection. Here, we propose and demonstrate three-ports polarimeters comprising on-chip chiral plasmonic metamaterial-mediated mid-infrared photodetectors for full-Stokes detection. By manipulating the spatial distribution of chiral metamaterials, we could convert polarization-resolved absorptions to corresponding polarization-resolved photovoltages of three ports through the photothermoelectric effect. We utilize the developed polarimeter in an imaging demonstration showing reliable ability for polarization reconstruction. Our work provides an alternative strategy for developing polarization-resolved photodetectors with a bandgap-independent operation range in the mid-infrared.

Improving plasmonic photodetector based on ITO/TiO2/Ag configuration and roughened interface

In this work, plasmonic photodetector based on ITO/TiO2/Ag grating configuration specially with nano-scale roughened interface is proposed to achieve high photoresponsivity, in which hot-electron are effectively excited by taking advantages of the narrow distribution of excitation energy in Ag and the high density of states in TiO2 conduction band. Simultaneously, a roughened structure is introduced at Ag/TiO2 interface to alleviate the momentum mismatch of hot-electron. The influences of the grating structures on incident light absorption and hot-electron excitation are simulated by using finite-difference time-domain method. The thicknesses of both metallic Ag and spacer layers modulate the absorption characteristics, and the introduction of the nano-scale roughened interface does not have effect obviously on the absorptivity and response wavelength. The present work provides a valuable guidance in the fields of interface design and structure optimization of high-efficiency plasmonic photodetectors.

Photocurrent detection of radially polarized optical vortex with hot electrons in Au/GaN

We report a GaN based metal–semiconductor–metal (MSM) infrared photodetector enabled with azimuthally distributed sub-wavelength gratings fabricated on one of the working electrodes. Under illumination, hot electron transfer is introduced by the plasmonic resonance in the infrared waveband formed at the interface of Au/GaN. Without the help of using any external optical polarizers, the device is able to detect radial polarization vortices in the form of photocurrents with a prescribed response spectrum. The detector exhibits a 10%–90% rise and fall time of 0.9 ms under modulated light, much faster than that of conventional ultraviolet GaN MSM photodetectors based on the band edge absorption. This work provides a viable way to measure spatially variant polarization beams with a compact plasmonic photodetectors fabricated from wide bandgap semiconductors.

Nanophotonic Materials for Twisted-Light Manipulation.

Twisted light, an unbounded set of helical spatial modes carrying orbital angular momentum (OAM), offers not only fundamental new insights into structured light-matter interactions, but also a new degree of freedom to boost optical and quantum information capacity. However, current OAM experiments still rely on bulky, expensive, and slow-response diffractive or refractive optical elements, hindering today's OAM systems to be largely deployed. In the last decade, nanophotonics has transformed the photonic design and unveiled a diverse range of compact and multifunctional nanophotonic devices harnessing the generation and detection of OAM modes. Recent metasurface devices developed for OAM generation in both real and momentum space, presenting design principle and exemplary devices, are summarized. Moreover, recent development of whispering-gallery-mode-based passive and tunable microcavities, capable of extracting degenerate OAM modes for on-chip vortex emission and lasing, is summarized. In addition, the design principle of different plasmonic devices and photodetectors recently developed for on-chip OAM detection is discussed. Current challenges faced by the nanophotonic field for twisted-light manipulation and future advances to meet these challenges are further discussed. It is believed that twisted-light manipulation in nanophotonics will continue to make significant impact on future development of ultracompact, ultrahigh-capacity, and ultrahigh-speed OAM systems-on-a-chip.

Room temperature plasmonic graphene hot electron bolometric photodetectors: A comparative analysis

The performance of a recently proposed integrated graphene-bolometric photodetector is assessed. The responsivity of hundreds of A/W and speed on the scale of hundreds of GHz are predicted. The impressive performance is attributed to the small length over which the energy is absorbed by graphene. The short length leads to a highly enhanced energy density, which causes the increase of the electron temperature in graphene. The model has been validated against recently published experimental results from high-speed graphene photodetectors and found to be in good agreement.

Engineering Surface Plasmons in Metal/Nonmetal Structures for Highly Desirable Plasmonic Photodetectors

Recently, small-size photodetectors have attracted considerable attention, because of their promising potential for superintegrated circuits in the photoelectric sensor system. However, the small size may disable the photodetectors or result in low photoelectric conversion efficiency, because of the optical diffraction limit and the inefficient light absorption. Encouragingly, plasmonic nanostructures take excellent advantage of light-confinement effect and electric fields enhancement at the nanoscale, providing huge opportunities to achieve small-size photodetectors while maintaining high device performance (broad photodetection range, high photoresponsivity, and fast response speed). This Review highlights the state-of-the art progress in the development of photodetectors based on various plasmonic structures. Since surface plasmons are well-controlled by the shape, size, and component of nanostructures, special emphasis will be put on the rational regulation of plasmonic nanostructures including metal nanostructures, doped semiconductors, and graphene to achieve high-performance photodetectors. In addition, the underlying enhanced mechanism is also discussed. Finally, we highlight the challenges that require deeper insights into the underlying plasmon enhanced mechanism, develop inexpensive plasmonic nanostructures for practical application, and need more research on plasmonic photodetectors based on nonmetal nanostructures and provide perspectives for future research. This Review may provide guidance for rational design of plasmonic nanostructures for small-size photodetectors with high performance.

Stretchable Broadband Plasmonic Photodetector Based on a Hybrid and Composite of Metal Nanoparticles and Organic Semiconductor

AbstractThe development of stretchable broadband photodetectors for applications in wearable optoelectronics and personal healthcare still has some limitations in obtaining materials, designing device structures, and developing reliable fabrication processes. Here, stretchable broadband plasmonic photodetectors (SBPPDs) by fabricating plasmonic photodetectors on a stress‐adaptable modulated polydimethylsiloxane (PDMS) substrate are proposed. The plasmonic photodetectors are developed via two approaches for the sensing layers: (i) hybrid of silver nanoparticles (AgNPs) with poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and (ii) nanocomposite of AgNPs embedded into PEDOT:PSS. These sensing layers are directly formed on the substrate to be capable of sustaining tensile strain. The working principle of SBPPDs is based on the injection of hot‐carriers generated from surface plasmon decay on AgNPs to PEDOT:PSS under visible (Vis) and near‐infrared (NIR) illumination. Both SBPPDs show high responsivity to wavelengths of Vis (565 nm), Vis (660 nm), NIR (880 nm), and NIR (970 nm) as well as reliable electrical performance under applied stretching up to 30%. The proposed SBPPDs are promising for future stretchable wearable optoelectronics.