- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Graphene Heterostructure Integrated Optical Fiber Bragg Grating for Light Motion Tracking and Ultrabroadband Photodetection from 400 nm to 10.768 μm
摘要： Integrated photonics and optoelectronics devices based on graphene and related 2D materials are at the core of the future industrial revolution, facilitating compact and flexible nanophotonic devices. Tracking and detecting the motion of broadband light in millimeter to nanometer scale is an unfold science which has not been fully explored. In this work, tracking and detecting the motion of light (millimeter precision) is first demonstrated by integrating graphene with an optical fiber Bragg grating device (graphene-FBG). When the incident light moves toward and away from the graphene-FBG device, the Bragg wavelength red-shifts and blue-shifts, indicating its light motion tracking ability. Such light tracking capability can be further extended to an ultrabroad wavelength range as all-optical photodetectors show the robust response from 400 nm to 10.768 μm with a linear optical response. Interestingly, it is found that graphene-Bi2Te3 heterostructure on FBG shows 87% higher photoresponse than graphene-FBG at both visible and telecom wavelengths, due to stronger phonon-electron coupling and photo-thermal conversion in the heterostructure. The device also shows superior stability even after 100 d. This work may open up amazing integrated nanophotonics applications such as astrophysics, optical communication, optical computing, optical logic gating, spectroscopy, and laser biology.
关键词： 2D materials,graphene,ultrabroadband photodetection,heterostructures,optical fiber Bragg grating,light motion tracking
更新于2025-11-28 14:24:03
-
Single-Crystal ZnO/AlN Core/Shell Nanowires for Ultraviolet Emission and Dual-Color Ultraviolet Photodetection
摘要： Core–shell nanostructures can combine the advantages of different functional materials to realize property tunability and enhance optical and optoelectrical performance. Here, vertically aligned ZnO/AlN core/shell nanowires have been facilely fabricated by sputtering AlN layer onto the ZnO nanowires grown by vapor phase transport. The morphological and structural characterization reveals that single-crystal AlN shell layer with thickness of ≈15 nm is coated uniformly on the single-crystal ZnO nanowire with diameters of ≈330 nm. The core/shell nanowire exhibits 24 times enhancement of ultraviolet emission and quenching of the deep level emission from ZnO. Moreover, under ultraviolet irradiation (325 nm), the photodetector based on the core/shell nanowire displays higher photoresponsivity (from 3.8 × 103 to 2.05 × 104 A W?1), faster response speed (from 397 to 28 ms), and higher I325nm/Idark ratio (from 453 to 1.1 × 104) than that bare ZnO nanowire device. Under the vacuum ultraviolet (193 nm) illumination, the I193nm/Idark ratio and photoresponsivity are 300 and 381 A W?1, respectively. In one word, this paper employs a facile and general technique to solve a challenging fabrication issue, and obtains perfect crystal core/shell structure with high performance for ultraviolet emission and detection.
关键词： single-crystal core/shell,AlN,ZnO nanowires,ultraviolet emission,dual-color ultraviolet photodetection
更新于2025-09-23 15:23:52
-
Planar hot-electron photodetector utilizing high refractive index MoS<sub>2</sub> in fabry-p??rot perfect absorber
摘要： Hot electron photodetection (HEPD) excited by surface plasmon can circumvent bandgap limitations, opening pathways for additional energy harvesting. However, the costly and time-consuming lithography and electron beam lithography-free hot electron photodetector based on the Fabry-Pérot resonance has long been a barrier for large-area and mass production of HEPD. In this paper, we proposed a planar and electron beam lithography-free hot electron photodetector based on the Fabry-Pérot resonance composed of Au/MoS2/Au cavity. The hot electron photodetector has a nanoscale thickness, high spectral tenability, and multicolour photoresponse in the near-infrared region due to the increased round-trip phase shift by using high refractive index MoS2. We predict that the photoresponsivity can achieve up to 23.6 mA/W when double cavities are integrated with the Fabry-Pérot cavity. The proposed hot electron photodetector that has a nanoscale thickness and planar stacking is a perfect candidate for large-area and mass production of HEPD.
关键词： Hot electron,photodetection,Molybdenum disulphide,Fabry-Pérot resonance,perfect absorption
更新于2025-09-23 15:21:01
-
[IEEE 2019 Device Research Conference (DRC) - Ann Arbor, MI, USA (2019.6.23-2019.6.26)] 2019 Device Research Conference (DRC) - Tunable WSe <sub/>2</sub> phototransistor enabled by electrostatically doped lateral p-n homojunction
摘要： This study demonstrates an approach to tune the responsivity and detectivity of a WSe2 phototransistor by incorporating an electrostatically doped lateral p-n junction in the form of side gates to the transistor channel. The resulting decrease in dark current and enhancement in photocurrent by externally injected carriers into the conduction channel leads to improved photodetection with a fast response time (τ).
关键词： photodetection,phototransistor,lateral p-n junction,electrostatic doping,WSe2
更新于2025-09-23 15:21:01
-
Quantum dot based mid-infrared photodetector enhanced by a hybrid metal-dielectric optical antenna
摘要： Surface plasmon waves and Rayleigh anomaly are characteristic optical phenomena exhibited by periodic subwavelength grating structures. In this paper, a hybrid metal-dielectric metasurface is proposed to improve the photoresponse of Ge/Si quantum dot infrared photodetectors (QDIPs) with the limited absorption layer thickness. The composite metasurface consists of a regular array of silicon pillars. The pillars protrude through subwavelength holes in a perforated gold ?lm on detector top. We demonstrate that by combining e?ects of dielectric and plasmonic metal components, the QDIP photoresponse can be signi?cantly improved compared to case when all-dielectric and metal gratings work alone. We observe about 4 times photoresponse enhancement with the hybrid metasurface device relative to a common plasmonic design with the two-dimensional metal hole array. Compared with a bare QDIP, the peak responsivity of the hybrid detector at a wavelength of 4.4 μm is increased by a factor of 15. The enhanced sensitivity is supposed to arise from coupling of the surface plasmon resonance and di?ractive e?ect related to the Rayleigh anomaly.
关键词： infrared photodetection,quantum dots,surface plasmons,enhancement,near-?eld
更新于2025-09-23 15:21:01
-
Wafer-Scale Fabrication of 2D PtS <sub/>2</sub> /PtSe <sub/>2</sub> Heterojunctions for Efficient and Broadband Photodetection
摘要： The fabrication of van der Waals heterostructures have mainly extends to two-dimensional materials that are exfoliated from their bulk counterparts, which is greatly limited by high-volume manufacturing. Here, we demonstrate multilayered PtS2/PtSe2 heterojunctions covering a large area on SiO2/Si substrate with a maximum size of 2" in diameter, offering throughputs that can meet the practical application demand. Theoretical simulation was carried out to understand the electronic properties of the PtS2/PtSe2 heterojunctions. Zero-bias photoresponse in the heterojunctions is observed under laser illumination of different wavelengths (405 to 2200 nm). The PtS2/PtSe2 heterojunctions exhibit broadband photoresponse, high quantum efficiency at infrared wavelengths with lower bounds for the external quantum efficiencies (EQE) being 1.2% at 1064 nm, 0.2% at 1550 nm and 0.05% at 2200 nm, and also relatively fast response time at the dozens of millisecond level. The large area, broadband 2D heterojunction photodetector demonstrated in this work further corroborating the great potential of 2D materials in the future low-energy optoelectronics.
关键词： van der Waals heterostructures,self-driving operation,quantum efficiency,broadband photodetection,photoresponsivity,wafer-scale fabrication
更新于2025-09-23 15:21:01
-
Near-direct bandgap WSe <sub/>2</sub> /ReS <sub/>2</sub> type-II pn heterojunction for enhanced ultrafast photodetection and high-performance photovoltaics
摘要： PN heterojunctions comprising layered van der Waals (vdW) semiconductors have been used to demonstrate current-rectifiers, photodetectors, and photovoltaic devices. However, a direct or near-direct heterointerface bandgap for enhanced photogeneration in high light-absorbing few-layer vdW materials remains unexplored. In this work, for the first time, density functional theory calculations show that the heterointerface of few-layer group-6 transition metal dichalcogenide (TMD) WSe2 with group-7 ReS2 results in a sizeable (0.7 eV) near-direct type-II bandgap. The interlayer IR bandgap is confirmed through IR photodetection and micro-photoluminescence measurements demonstrate type-II alignment. Few-layer flakes exhibit ultrafast response time (5 μs) and high responsivity (3 A/W) and large photocurrent-generation and responsivity-enhancement at the hetero-overlap region (10-100×). Large open-circuit voltage of 0.64 V and short-circuit current of 2.6 μA enable high output electrical power. Finally, long term air-stability and facile single contact metal fabrication process make the multi-functional few-layer WSe2/ReS2 heterostructure diode technologically promising for next-generation optoelectronics.
关键词： van der Waals heterostructure,pn heterojunction,ultrafast photodetection,near-direct bandgap,infrared photodetection,interlayer bandgap
更新于2025-09-23 15:19:57
-
Improved Photoresponse of UV Photodetectors by the Incorporation of Plasmonic Nanoparticles on GaN Through the Resonant Coupling of Localized Surface Plasmon Resonance
摘要： Very small metallic nanostructures, i.e., plasmonic nanoparticles (NPs), can demonstrate the localized surface plasmon resonance (LSPR) effect, a characteristic of the strong light absorption, scattering and localized electromagnetic field via the collective oscillation of surface electrons upon on the excitation by the incident photons. The LSPR of plasmonic NPs can significantly improve the photoresponse of the photodetectors. In this work, significantly enhanced photoresponse of UV photodetectors is demonstrated by the incorporation of various plasmonic NPs in the detector architecture. Various size and elemental composition of monometallic Ag and Au NPs, as well as bimetallic alloy AgAu NPs, are fabricated on GaN (0001) by the solid-state dewetting approach. The photoresponse of various NPs are tailored based on the geometric and elemental evolution of NPs, resulting in the highly enhanced photoresponsivity of 112 A W?1, detectivity of 2.4 × 1012 Jones and external quantum efficiency of 3.6 × 104% with the high Ag percentage of AgAu alloy NPs at a low bias of 0.1 V. The AgAu alloy NP detector also demonstrates a fast photoresponse with the relatively short rise and fall time of less than 160 and 630 ms, respectively. The improved photoresponse with the AgAu alloy NPs is correlated with the simultaneous effect of strong plasmon absorption and scattering, increased injection of hot electrons into the GaN conduction band and reduced barrier height at the alloy NPs/GaN interface.
关键词： UV photodetection,NP-based photodetectors,Plasmonic enhancement,Nanoparticles
更新于2025-09-23 15:19:57
-
Interplay of charge transfer and disorder in optoelectronic response in Graphene/hBN/MoS<sub>2</sub> van der Waals heterostructures
摘要： Strong optoelectronic response in the binary van der Waals heterostructures of graphene and transition metal dichalcogenides (TMDCs) is an emerging route towards high-sensitivity light sensing. While the high sensitivity is an effect of photogating of graphene due to inter-layer transfer of photo-excited carriers, the impact of intrinisic defects, such as traps and mid-gap states in the chalcogen layer remain largely unexplored. Here we employ graphene/hBN (hexagonal boron nitride)/MoS2 (molybdenum disulphide) trilayer heterostructures to explore the photogating mechanism, where the hBN layer acts as interfacial barrier to tune the charge transfer timescale. We find two new features in the photoresponse: First, an unexpected positive component in photoconductance upon illumination at short times that preceeds the conventional negative photoconductance due to charge transfer, and second, a strong negative photoresponse at infrared wavelengths (up to 1720 nm) well-below the band gap of single layer MoS2. Detailed time and gate voltage-dependence of the photoconductance indicates optically-driven charging of trap states as possible origin of these observations. The responsivity of the trilayer structure in the infrared regime was found to be extremely large (> 108 A/W at 1550 nm using 20 mV source drain bias at 180 K temperature and ≈ ?30 V back gate voltage). Our experiment demonstrates that interface engineering in the optically sensitive van der Waals heterostructures may cast crucial insight onto both inter- and intra-layer charge reorganization processes in graphene/TMDC heterostructures.
关键词： defects and disorders in TMDCs,monolayer MoS2,phototransistor,graphene,infrared photodetection,Van der Waals heterostructures
更新于2025-09-23 15:19:57
-
In Situ Formed Gradient Bandgapa??Tunable Perovskite for Ultrahigha??Speed Color/Spectruma??Sensitive Photodetectors via Electrona??Donor Control
摘要： Integration of various photodetectors with different light-sensitive materials and detection capacity is an inevitable way to achieve entire color/spectrum detection. However, the uneven capacity of each photodetector would drag the overall performance behind, especially the response speed. A response time down to nanosecond level has not previously been reported for a filter-free color/spectrum-sensitive photodetector, as far as is known. Here, a self-powered filterless color-sensitive photodetection array based on an in situ formed gradient perovskite absorber film with continuously tunable bandgap is demonstrated. Ultrahigh-speed response at nanosecond level is achieved in all the ingredient photodetectors. The junction capacitance being influenced by carrier concentration in the absorber is identified to be responsible for the detection speed. Without any optic or mechanical supporting system, the designed color detector exhibits an external quantum efficiency (EQE) up to 94% and a high spectral resolution of around 80 nm for the whole visible spectrum. This work offers a guidance to achieve fast response of perovskite-based photodetectors from the point of view of carrier-donor control and demonstrates a new avenue to establish color-sensitive photodetectors/spectrometers.
关键词： photodetectors,self-powered devices,color-sensitive photodetection,spectrum analysis,perovskites
更新于2025-09-23 15:19:57