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Fast Photoelectric Conversion in the Near‐Infrared Enabled by Plasmon‐Induced Hot‐Electron Transfer
摘要： Interfacial charge transfer is a fundamental and crucial process in photoelectric conversion. If charge transfer is not fast enough, carrier harvesting can compromise with competitive relaxation pathways, e.g., cooling, trapping, and recombination. Some of these processes can strongly affect the speed and efficiency of photoelectric conversion. In this work, it is elaborated that plasmon-induced hot-electron transfer (HET) from tungsten suboxide to graphene is a sufficiently fast process to prevent carrier cooling and trapping processes. A fast near-infrared detector empowered by HET is demonstrated, and the response time is three orders of magnitude faster than that based on common band-edge electron transfer. Moreover, HET can overcome the spectral limit of the bandgap of tungsten suboxide (≈2.8 eV) to extent the photo-response to the communication band of 1550 nm (≈0.8 eV). These results indicate that plasmon-induced HET is a new strategy for implementation of efficient and high-speed photoelectric devices.
关键词： localized surface plasmon resonance,infrared photodetection,photoelectric conversion,hot-electron transfer,graphene
更新于2025-09-11 14:15:04
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Integration of MoS <sub/>2</sub> with InAlAs/InGaAs Heterojunction for Dual Color Detection in Both Visible and Near‐Infrared Bands
摘要： At present, dual-channel or even multi-channel recording is a developing trend in the field of photodetection, which is widely applied in environment protection, security, and space science and technology. This paper proposes a novel MoS2/InAlAs/InGaAs n–i–n heterojunction phototransistor by integrating multi-layered MoS2 with InGaAs-based high electron mobility transistors (InGaAs-HEMTs). Due to the internal photocurrent amplification in the InGaAs channels with a narrow energy bandgap of 0.79 eV, this device exhibits high photoresponsivity (R) of over 8 × 105 A W–1 under near-infrared illumination of 1550 nm at 500 pW. Furthermore, with the combination of the photoconductance effect in the vertical MoS2/InAlAs/InGaAs n–i–n heterojunction and the photogating effect in the lateral phototransistor, this device possesses a unique characteristic under visible illumination that its photoresponsivity can be tuned by the top gate electrode from 6 × 105 A W–1 to -4 × 105 A W–1 by gate voltage. This may lead to a new application as an optically controlled electronic inverter, which needs further study in depth. This MoS2/InAlAs/InGaAs phototransistor builds up a new bridge between 2D materials and conventional ternary compounded semiconductor devices.
关键词： MoS2/InAlAs/InGaAs van der Waals heterojunction,gate-tunable negative/positive responsivity,dual-band photodetection,2D electron gas
更新于2025-09-11 14:15:04
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Hot-electron photodetector with wavelength selectivity in near-infrared via Tamm plasmon
摘要： Tamm plasmonic (TP) structures, consisting of a metallic film and a distributed Bragg reflector (DBR), can exhibit pronounced light confinement allowing for enhanced absorption in the metallic film at the wavelength of the TP resonance. This wavelength dependent absorption can be converted into an electrical signal through the internal photoemission of energetic hot-electrons from the metallic film. Here, by replacing the metallic film at the top of a TP structure with a hot-electron device in a metal-semiconductor-ITO (M-S-ITO) configuration, for the first time, we experimentally demonstrate a wavelength-selective photoresponse around the telecommunication wavelength of 1550 nm. The M-S-ITO junction is deliberately designed to have a low energy barrier and an asymmetrical hot-electron generation, in order to guarantee a measurable net photocurrent even for sub-bandgap incident light with a photon energy of 0.8 eV (1550 nm). Due to the excitation of TPs between the metallic film in the M-S-ITO structure and the underlying DBR, the fabricated TP coupled hot-electron photodetector exhibits a sharp reflectance dip with a bandwidth of 43 nm at a wavelength of 1581 nm. The photoresponse matches the absorptance spectrum, with a maximum value of 8.26 nA/mW at the absorptance peak wavelength that decreases by more than 80% when the illumination wavelength is varied by only 52 nm (from 1581 to 1529 nm), thus realizing a high modulation wavelength-selective photodetector. This study demonstrates a high-performance, lithography-free, and wavelength-selective hot-electron near-infrared photodetector structure.
关键词： hot-electron photodetector,near-infrared,wavelength-selective photodetection,Tamm plasmonic structures,telecommunication wavelength
更新于2025-09-11 14:15:04
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High-performance nitrogen doped carbon quantum dots: Facile green synthesis from waste paper and broadband photodetection by coupling with ZnO nanorods
摘要： High-performance N-doped carbon quantum dots (NCQDs) were synthesized by a proposed green route based on hydrothermal treatments using waste paper and urea as C and N sources. The single-crystalline NCQDs demonstrated strong blue-green luminescence with the maximum intensity enhancement of 6.5 times when compared with undoped CQDs under UV and visible light excitations. XPS spectra results suggested that the enhanced photoluminescence might be attributed to pyridinic N, which could be controlled by adjusting hydrothermal temperature, time, and urea concentration. The NCQDs having excellent optoelectronic properties were fabricated into broadband photodetectors by incorporating ZnO nanorod arrays. Owing to the NCQDs, the detectors demonstrated broadband photoresponse with significantly enhanced photoresponsivity, faster response, and better sensitivity in visible range. The work provides a low-cost, environment friendly route to fabricate excellent NCQD-based broadband photodetectors for various technological applications.
关键词： Photodetection,ZnO,Broadband,Nitrogen,Carbon quantum dot
更新于2025-09-11 14:15:04
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Low-cost photodetector architectures fabricated at room-temperature using nano-engineered silicon wafer and sol-gel TiO2 – based heterostructures
摘要： In the last decades, significant research has been done on the nanocrystalline forms of titanium dioxide (tio2). Amorphous TiO2 has not been studied intensively despite being significantly less expensive compared to crystalline TiO2. This study reveals significant improvement in UV-VIS photodetection properties from heterostructures fabricated in ambient environment using n-type silicon nanowire arrays and amorphous TiO2 sol-gel. Our ultra-low-cost UV-VIS photodetectors can cover a wide range of applications. We report fast rise/decay time constants of 0.23 ms/0.17 ms and high responsivity up-to 6.0 A/W in the UV and 25.0 A/W in the visible range under low (1 V) external bias. The large surface area due to the nanowire array architecture leads to 2 orders of magnitude enhancement in photo-response. Besides the final electrode deposition, the entire device fabrication is performed using low-cost, all solution-based methods in ambient conditions. These low-cost UV-Visible broadband photodetectors can potentially serve a wide range of applications.
关键词： heterostructures,UV-VIS photodetection,TiO2,silicon nanowire,photodetector
更新于2025-09-11 14:15:04
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High-Performance Organic Photodetectors by Introducing a Non-Fullerene Acceptor to Broaden Long Wavelength Detective Spectrum
摘要： We demonstrate the broadband visible organic photodetectors (OPDs) by introducing a non-fullerene acceptor of 3,9-bis(2-methylene-(3-(1,1dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3d:2,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITIC) into the bulk heterojunction (BHJ) based on a conventional system of poly(3-hexylthiophene-2,5-diyl) (P3HT):[6,6]-phenyl C71-butyric acid methyl ester (PC71BM) .The resultant OPDs exhibit a specific detectivity beyond 1012 Jones in the whole visible region ranged from 380 nm to 760 nm, and the highest detectivity reaches 2.67 × 1012 Jones at 710 nm. UV-Vis absorption spectrum, steady-state photoluminescence, atomic force microscopy, and space-charge-limited current property were applied to analyze the film characteristics of obtained OPDs. Owing to the long-wavelength absorption band of ITIC, the spectral photodetection range has been broadened effectively, and better film morphology, more effective energy transfer, and the reduced electron mobility in the active layer are responsible for the excellent photodetection capability. The proposed scheme provides a reliable strategy for implementing high-performance broadband visible OPDs.
关键词： Organic photodetectors,UV-Vis absorption,Non-fullerene acceptor,Surface morphology,Full visible light photodetection
更新于2025-09-11 14:15:04
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Ultrawide‐Bandgap Amorphous MgGaO: Nonequilibrium Growth and Vacuum Ultraviolet Application
摘要： New ultrawide-bandgap (>6.0 eV) photosensitive materials are in urgent need to meet the requirements of vacuum-ultraviolet (VUV) photodetection applied in deep space exploration. Here, a nonequilibrium growth method is reported to fabricate amorphous MgGaO (a-MgGaO) films with an ultrawide bandgap of 6.0 eV and an ultrashort absorption edge of 206 nm by alloying MgO and Ga2O3. By combining the as-grown films with p-type graphene (p-Gr) which serves as a transparent conductor, a vacuum-ultraviolet photovoltaic detector of p-Gr/a-MgGaO/n-SiC (n-type SiC) is constructed. The device exhibits an excellent VUV spectral selectivity with a VUV (185 nm)/UV (250 nm) rejection ratio exceeding 103, high photoresponsivity (≈10.3 mA W?1) under 0 V bias, and ultrafast response and recovery time of 1.94 μs and 0.6 ms, respectively. The reported nonequilibrium growth method is expected to have tremendous potential in fabricating ultrawide-bandgap oxide compounds, and finally facilitate future deep space exploration.
关键词： nonequilibrium growth,vacuum-ultraviolet photodetection,graphene,band engineering,MgGaO
更新于2025-09-04 15:30:14
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Omnidirectional sub-bandgap photo-detection using functionalized moulded composite flexible platforms
摘要： The substrate is an optically functional component of a thin film organic optoelectronic device. In the well-known context of photovoltaics, the functionality of substrate is relatively simple – that of a broadband transmittance which allows almost all the incoming light into the absorber. A less explored idea is that of incorporating other optical functionalities in the substrate bulk. Such unconventional design can help surpass the performance limitations of commonly available optoelectronic materials to achieve novel functionality. Bulk functionalization of substrates is particularly easy when the substrates are made using moldable transparent materials which allow mixing of optically functional materials into a composite substrate bulk. In this paper, the example of photonic-upconversion is considered as a representative optical function, to make organic photo-detectors which detect up-converted infrared light. By incorporating this functionality in a composite substrate two advantages are demonstrated in which the composite substrate architecture surpasses the performance of the conventional thin film device design. First, the composite substrate preserves the electronic performance of the device by spatially isolating the optical and the charge transport functions. Second, the composite architecture enables sub-bandgap photo-detection which is invariant with respect to the angle of incidence of the infrared input light, by placing the optical function before the light can encounter optically reflecting interfaces. In summary, the unconventional design employing a composite optically functional substrate can be extended to multiple optical functionalities and represents a key design finding that can enable considerably more efficient optoelectronic device designs.
关键词： Functionalization,Optoelectronic device,Moulded substrate,Composite,Up-conversion,Photodetection
更新于2025-09-04 15:30:14
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Photodetection probability in quantum systems with arbitrarily strong light-matter interaction
摘要： Cavity-QED systems have recently reached a regime where the light-matter interaction strength amounts to a non-negligible fraction of the resonance frequencies of the bare subsystems. In this regime, it is known that the usual normal-order correlation functions for the cavity-photon operators fail to describe both the rate and the statistics of emitted photons. Following Glauber’s original approach, we derive a simple and general quantum theory of photodetection, valid for arbitrary light-matter interaction strengths. Our derivation uses Fermi’s golden rule, together with an expansion of system operators in the eigenbasis of the interacting light-matter system, to arrive at the correct photodetection probabilities. We consider both narrow- and wide-band photodetectors. Our description is also valid for point-like detectors placed inside the optical cavity. As an application, we propose a gedanken experiment confirming the virtual nature of the bare excitations that enrich the ground state of the quantum Rabi model.
关键词： Cavity-QED,light-matter interaction,ultrastrong coupling,quantum Rabi model,photodetection
更新于2025-09-04 15:30:14