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Flexible and Selfa??Powered Photodetector Arrays Based on Alla??Inorganic CsPbBr <sub/>3</sub> Quantum Dots
摘要： Flexible devices are garnering substantial interest owing to their potential for wearable and portable applications. Here, flexible and self-powered photodetector arrays based on all-inorganic perovskite quantum dots (QDs) are reported. CsBr/KBr-mediated CsPbBr3 QDs possess improved surface morphology and crystallinity with reduced defect densities, in comparison with the pristine ones. Systematic material characterizations reveal enhanced carrier transport, photoluminescence efficiency, and carrier lifetime of the CsBr/KBr-mediated CsPbBr3 QDs. Flexible photodetector arrays fabricated with an optimum CsBr/KBr treatment demonstrate a high open-circuit voltage of 1.3 V, responsivity of 10.1 A W?1, specific detectivity of 9.35 × 1013 Jones, and on/off ratio up to ≈104. Particularly, such performance is achieved under the self-powered operation mode. Furthermore, outstanding flexibility and electrical stability with negligible degradation after 1600 bending cycles (up to 60°) are demonstrated. More importantly, the flexible detector arrays exhibit uniform photoresponse distribution, which is of much significance for practical imaging systems, and thus promotes the practical deployment of perovskite products.
关键词： self-powered devices,perovskites,flexible devices,photodetector arrays
更新于2025-09-23 15:19:57
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Surface modification of AlN using organic molecular layer for improved deep UV photodetector performance
摘要： Direct wide bandgap of 6.2 eV, high temperature robustness and radiation hardness make aluminum nitride (AlN) a preferable semiconductor for deep ultraviolet (UV) photodetection. However, the performance and reliability of AlN- based devices is adversely affected by a large density of surface states present in AlN. In this work, we have investigated the potential of a monolayer of organic molecules in passivating the surface states of AlN which improved the performance of AlN- based metal- semiconductor- metal (MSM) deep UV photodetectors. The organic molecules of Meso-5,10,15-triphenyl-20-(p-hydroxyphenyl)porphyrin Zn(II) complex (ZnTPP(OH)) were successfully adsorbed on AlN surface, forming a self- assembled monolayer (SAM). The molecular layer was characterized by contact angle measurement, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The surface modification of AlN effectively reduced dark current of the photodetector by ten times without degrading the magnitude of photo current, especially at low voltages. Photo to dark current ratio (PDCR) was enhanced from 930 to 7835 at -2V and the responsivity doubled from 0.3 mA/W to 0.6 mA/W at 5V. Moreover, the rise and fall times of the detector were found to decrease after the surface modification process. Our results suggest that SAM of porphyrin molecules effectively passivated the surface states in AlN which resulted in improved photodetector performance.
关键词： Dark current,PDCR,MSM UV photodetector,Surface states,SAM,Responsivity,Temporal response
更新于2025-09-23 15:19:57
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Nonvolatile Programmable WSe <sub/>2</sub> Photodetector
摘要： Optoelectronic devices with nonvolatile memory are an important component in a wide variety of applications ranging from optoelectronic random-access-memories, with the advantage of using optical stimuli as an added parameter, to complex artificial neuromorphic networks that pretend to mimic the working schemes of the human brain. In the past few years, 2D materials have been proposed as attractive candidates to build such optoelectronic devices with memory due to their excellent optoelectronic properties and high sensitivity to external electric fields. Here, a WSe2 monolayer p–n junction working as a nonvolatile programmable photodetector is reported, that, enabled by a split-gate configuration with embedded charge-trapping layers, is capable of retaining custom responsivity values over time, prior configuration by the user. Once configured, this photodetector can operate without external applied bias voltage as a self-driven photodetector, as well as without external back-gate voltage thanks to the charge stored in the floating gates. Furthermore, the device shows a remarkable performance, with open-circuit voltage around 1 V at approximately 270 W m?2 white light, fill factor higher than 30%, and fast response times. This programmable photodetector sets a new concept as a building block in more complex image-sensing systems.
关键词： programmable photodetector,tungsten-diselenide,2D materials,photodetectors,floating gates,nonvolatile memories
更新于2025-09-23 15:19:57
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Compact Graphene Plasmonic Slot Photodetector on Silicon-on-insulator with High Responsivity
摘要： Graphene has extraordinary electro-optic properties and is therefore a promising candidate for monolithic photonic devices such as photodetectors. However, the integration of this atom-thin layer material with bulky photonic components usually results in a weak light-graphene interaction leading to large device lengths, limiting electro-optic performance. In contrast, here we demonstrate a plasmonic slot graphene photodetector on silicon-on-insulator platform with high responsivity of 0.7 A/W given a just 5 μm-short device length. We observe that the maximum photocurrent, and hence the highest responsivity, scales inversely with the slot width. Using a dual-lithography step, we realize 15 nm narrow slots that show a 30-times higher responsivity per unit device-length compared to photonic graphene photodetectors. Furthermore, we reveal that the back-gated electrostatics is overshadowed by channel-doping contributions induced by the contacts of this ultra-short channel graphene photodetector. This leads to quasi charge neutrality, which explains both the previously-unseen offset between the maximum photovoltaic-based photocurrent relative to graphene’s Dirac point and the observed non-ambipolar transport. Such micrometer compact and absorption-efficient photodetectors allow for short-carrier pathways in next-generation photonic components, while being an ideal testbed to study short-channel carrier physics in graphene optoelectronics.
关键词： plasmonics,photovoltaic effect,graphene,photodetector,bolometric effect,Silicon photonics
更新于2025-09-23 15:19:57
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High-performance monolayer MoS2 photodetector enabled by oxide stress liner using scalable chemical vapor growth method
摘要： MoS2, as a typical representative of two-dimensional semiconductors, has been explored extensively in applications of optoelectronic devices because of its adjustable bandgap. However, to date, the performance of the fabricated photodetectors has been very sensitive to the surrounding environment owing to the large surface-to-volume ratio. In this work, we report on large-scale, high-performance monolayer MoS2 photodetectors covered with a 3-nm Al2O3 layer grown by atomic layer deposition. In comparison with the device without the Al2O3 stress liner, both the photocurrent and responsivity are improved by over 10 times under 460-nm light illumination, which is due to the tensile strain induced by the Al2O3 layer. Further characterization demonstrated state-of-the-art performance of the device with a responsivity of 16.103 A W?1, gain of 191.80, NEP of 7.96?×?10?15 W Hz?1/2, and detectivity of 2.73?×?1010 Jones. Meanwhile, the response rise time of the photodetector also reduced greatly because of the increased electron mobility and reduced surface defects due to the Al2O3 stress liner. Our results demonstrate the potential application of large-scale strained monolayer MoS2 photodetectors in next-generation imaging systems.
关键词： photodetector,Al2O3,stress liner,monolayer MoS2
更新于2025-09-23 15:19:57
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Morphology Effect of 1D ZnO Nanostructures Designed by Hydrothermal and Thermal Annealing for Fast Ultraviolet Photodetector Applications
摘要： Zinc oxide (ZnO) nanorods were grown on a ZnO seed layer using the hydrothermal method and subsequently annealed at temperatures of 400–800 °C. The ZnO nanorods annealed at 400 °C exhibited morphology similar to that of the unannealed ZnO nanorods. However, the tips of the ZnO nanorods gradually became rounded and their density and diameter increased with an increase in the annealing temperature. The intensity of the near-band-edge emission increased gradually with an increase in the annealing temperature from 400 to 600 °C but decreased sharply in the case of the nanorods annealed at 800 °C. With respect to the deep-level emissions, broad yellow, orange, and green emissions were observed. Further, the low-temperature photoluminescence spectrum measured at 12 K of the ZnO nanorods annealed at 600 °C contained a donor-bound exciton emission, as well as emissions related to the donor-acceptor pair transition and the first-order and second-order longitudinal optical phonon replicas of the donor-acceptor pair transition. Finally, with respect to the photoresponse, the dark current and photocurrent of the nanorods decreased and their photosensitivity increased with the increase in the annealing temperature.
关键词： Ultraviolet photodetector,Zinc oxide,Photosensitivity,Photoluminescence,Hydrothermal method
更新于2025-09-23 15:19:57
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Investigation of modulation transfer function in InGaAs photodetector small pitch array based on three-dimensional numerical analysis
摘要： Three-dimensional numerical simulation technology was used to investigate the influence of structural and material parameters on the modulation transfer function (MTF) of lattice matched InGaAs/InP planar small pitch arrays. We found that extending depletion zone through increasing depth of diffusion junction and reducing the doping concentration in the absorption layer plays a critical role in optimizing the MTF of arrays. And it is highly worth noting that the very optimization effects become even more pronounced in smaller pitch arrays, which offers valuable references to restrain crosstalk in highly dense array and strengthen the imaging ability of large format photodetector system in future. However, the inevitable cost of deteriorating the specific detectivity should not be ignored. And hence, junction depth and doping concentration of the absorption layer need to be balanced in actual preparation. In addition, the effects of lattice temperature on MTF and crosstalk in arrays were also discussed. The inter-pixel crosstalk deteriorates seriously as rising lattice temperature. A stronger impact of lattice temperature on MTF of larger pitch arrays has been confirmed. This work offers important reference to suppress inter-pixel crosstalk in obtaining the high-resolution imaging for InGaAs photodetector focal plane array.
关键词： InGaAs photodetector array,Three-dimensional numerical analysis,Modulation transfer function,Crosstalk
更新于2025-09-23 15:19:57
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Effective shape-controlled synthesis of gallium selenide nanosheets by vapor phase deposition
摘要： The controlled synthesis of large and uniform gallium selenide (GaSe) crystals is crucial for its various applications based on the attractive properties of this emerging material. In this work, vapor phase growth of high-quality monolayer GaSe nanosheets with multiple shape and size is achieved by tuning the Ga/GaSe ratio in the precursor. A theoretical model based on density functional theory calculations and kinetic Wulff construction theory describe the observed shape evolution of the GaSe nanosheets. Results show that the Ga/Se ratio plays a critical role in the evolution of the domain shape and size. Moreover, the as-grown GaSe nanosheets show improved performance with photoresponse time less than 0.7 ms and responsibility up to 3,000 A/W. This study presents a previously unexplored strategy for the controlled growth of two-dimensional (2D) GaSe nanosheets for promising applications in next-generation optoelectronics.
关键词： shape-evolution,gallium selenide,photodetector,growth dynamics,controllable growth
更新于2025-09-23 15:19:57
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CdS core-Au/MXene-based photodetectors: Positive deep-UV photoresponse and negative UVa??Vis-NIR photoresponse
摘要： Exploring photodetectors with higher responsitivity and broader spectral response is crucial for optoelectronic applications. Inverse photoresponse is discovered from photodetectors based on cadmium sulfide modified by Au (CdS core-Au). The devices are capable of detecting photons with a broader spectrum from deep-ultraviolet to near-infrared. Under the illumination of visible light at 405 nm, negative photoresponse with higher responsivity (86 mA/W) and larger specific detectivity (1.34×1011 Jones) are observed owing to the thermal mechanism. Upon deep-ultraviolet light illumination, the photodetectors exhibit positive photoresponse. These findings provide a new approach to broad spectral photodetectors and other inventive optoelectronic devices.
关键词： broader spectrum,positive photoresponse,negative photoresponse,photodetector,CdS core-Au
更新于2025-09-23 15:19:57
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High-performing self-driven ultraviolet photodetector by TiO2/Co3O4 photovoltaics
摘要： Ultraviolet (UV) may provide the essential to maintain the human body and metabolism, however, excessive exposure to UV light is absolutely harmful. We may take advantage of the strong UV energy for energy conversion devices. A stable, simple and scalable heterojunction (TiO2/Co3O4) thin film was developed for UV-absorbing and visible-blind photovoltaic. Effective hole transport layer (HTL, NiO) insertion established photovoltaics, having a power conversion efficiency of 15.8%. The heterojunction exhibits the improved carrier lifetime from 1.94 ms to 9 ms, resulting in the enhancement of both photovoltage and photocurrent from 0.17 V to 0.78 V and from 0.54 mA cm-2 to 13.5 mA cm-2, respectively. The TiO2/Co3O4 device exhibits a photoresponse to a UV light intensity of 60 μW cm-2 in the presence of sunlight and works stable for over a year. The results indicate metal oxide heterojunction (TiO2/Co3O4) photovoltaic device could be useful for monitoring UV radiation exposure and cost-effective self-powered UV optoelectronics. The functional utilization of metal oxide layers would provide strong benefits for photoelectric devices, such as photodetectors and transparent solar cells.
关键词： Metal oxide,Visible-blind UV photodetector,TiO2/Co3O4 photovoltaics,Long-term stability
更新于2025-09-23 15:19:57