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Durable and stable UV–Vis perovskite photodetectors based on CH3NH3PbI3 crystals synthesized via a solvothermal method
摘要： The CH3NH3PbI3-based photodetectors were fabricated with a coplanar metal-semiconductor-metal (MSM) IDT patterned Au electrode configuration. The MSM-structured perovskite-based photodetectors exhibited a higher Ion/Ioff of about 3.77 × 102, and a response of 6.66 mA/W. Additionally, the photodetectors worked best under red illumination, and the rise and decay times were estimated to shorter than 0.04 s and 0.05 s. Especially, the durability and stability of these photodetectors were excellent, which can be exposed to the red light illumination over 1000 s. There were still stable photocurrent signal after 90 days. It indicated that the device possessed a longer durability and had a lifetime of exceeding 90 days. These outstanding performances could be potentially applicable for practical applications.
关键词： perovskite,stability,photodetectors,solvothermal method,durability
更新于2025-09-16 10:30:52
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Ultrahigh Responsivity Photodetectors of 2D Covalent Organic Frameworks Integrated on Graphene
摘要： 2D materials exhibit superior properties in electronic and optoelectronic fields. The wide demand for high-performance optoelectronic devices promotes the exploration of diversified 2D materials. Recently, 2D covalent organic frameworks (COFs) have emerged as next-generation layered materials with predesigned π-electronic skeletons and highly ordered topological structures, which are promising for tailoring their optoelectronic properties. However, COFs are usually produced as solid powders due to anisotropic growth, making them unreliable to integrate into devices. Here, by selecting tetraphenylethylene monomers with photoelectric activity, elaborately designed photosensitive 2D-COFs with highly ordered donor-acceptor topologies are in situ synthesized on graphene, ultimately forming COF-graphene heterostructures. Ultrasensitive photodetectors are successfully fabricated with the COFETBC–TAPT-graphene heterostructure and exhibited an excellent overall performance with a photoresponsivity of ≈3.2 × 107 A W?1 at 473 nm and a time response of ≈1.14 ms. Moreover, due to the high surface area and the polarity selectivity of COFs, the photosensing properties of the photodetectors can be reversibly regulated by specific target molecules. The research provides new strategies for building advanced functional devices with programmable material structures and diversified regulation methods, paving the way for a generation of high-performance applications in optoelectronics and many other fields.
关键词： photodetectors,graphene,covalent organic frameworks,2D materials
更新于2025-09-16 10:30:52
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Efficient UV photodetectors based on Ni-doped ZnS nanoparticles prepared by facial chemical reduction method
摘要： Ni-doped ZnS nanoparticles are synthesized by simple hydrothermal process for the utilization in UV photodetectors. Surface morphology of the prepared samples is investigated through high resolution transmission electron microscopy (HRTEM), which reveals that the prepared nanoparticles are smaller than 20 nm. The well visualized selected area electron diffraction rings suggests the nanocrystalline nature of the prepared nanoparticles with (hkl) planes (111), (220) and (311). The structural analysis is done by x-ray diffraction (XRD) studies; which reveal the decrease in crystallite size with increase in Ni-doping concentration. The device performance of the photodetectors is tested under UV-A light (wavelength ?365 nm) and found that the ability of the prepared devices increases with increase in Ni-doping concentration. This can be attributed to the enhanced surface to volume ratio and increase in charge carrier concentration. The adsorption-desorption of oxygen molecules on the nanoparticles’ surface is considered to be the mechanism for UV photodetection.
关键词： Hydrothermal process,UV-Photodetectors,ZnS nanoparticles
更新于2025-09-16 10:30:52
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Interfacea??Induced High Responsivity in Hybrid Graphene/GaAs Photodetector
摘要： Photodetectors based on two-dimensional (2D)/ three-dimensional (3D) semiconductor heterojunction structures are emerging as appealing candidates for high-sensitivity applications. The performances of these hybrid photodetectors are closely correlated with their current gain mechanism. Carrier recirculation is the most commonly reported mechanism. Recently, a Fermi level alignment mechanism was proposed for 2D graphene/0-dimensional (0D) quantum dot heterostructures because of the easy Fermi level tunability of the quantum dot. In this article, an interface-induced gain mechanism using this Fermi level alignment process is proposed and identified based on a 2D graphene/3D GaAs hybrid structure with comparative measurement configurations. Because of the high surface state density of GaAs, the photo-excited holes tend to become trapped at the graphene/GaAs interface, which can easily lower the interface Fermi level and the Fermi level in graphene via an alignment process. When combined with the high carrier mobility characteristics of graphene, a maximum current gain of 2520 and responsivity of 1321 A W?1 are achieved in the devices. This study clarifies the role of the interface states in the gain characteristics of some 2D/3D hybrid devices, with results that are instructive for optimal device design.
关键词： interface-induced gain,GaAs,responsivity,photodetectors,graphene
更新于2025-09-16 10:30:52
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Self-powered perovskite/CdS heterostructure photodetectors
摘要： Methylammonium lead halide perovskites have gained a lot of attention because of their remarkable physical properties and potential for numerous (opto)electronic applications. Here, high-performance photodetectors based on CH3NH3PbI3 (MAPbI3)/CdS heterostructures, are demonstrated. The resulting self-powered MAPbI3/CdS photodetectors show excellent operating characteristics including a maximum detectivity of 2.3×1011 Jones with responsivity of 0.43 A/W measured at 730 nm. A temporal response time of less than 14 ms was achieved. The mechanisms of charge separation and transport at the interface of the MAPbI3/CdS junction were investigated via conductive atomic force microscopy (C-AFM) and photoconductive atomic force microscopy (PC-AFM). Obtained results show that grain boundaries exhibit higher photocurrent than flat regions of the top perovskite layer, which indicates that excitons preferentially separate at the grain boundaries of the perovskite thin film, i.e. at the edges of the MAPbI3 crystals. The study of the photoelectric mechanism at the nanoscale suggests the device performance could potentially be fine-tuned through grain boundary engineering, which provides essential insights for the fabrication of high-performance photodetector. The demonstrated self-powered photodetector is promising for numerous applications in low-energy consumption optoelectronic devices.
关键词： perovskite,photodetector,heterojunction,photovoltaic,self-powered photodetectors,photoconductive atomic force microscopy
更新于2025-09-16 10:30:52
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Self-Powered SnS1-xSex Alloy/Silicon Heterojunction Photodetectors with High Sensitivity in a Wide Spectral Range
摘要： Alloy engineering and heterostructures designing are two efficient methods to improve the photosensitivity of 2D material-based photodetectors. Herein, we report the first-principle calculation about the band structure of SnS1-xSex (0 ≤ x ≤ 1) and synthesize these alloy nanosheets. Systematic measurements indicate that SnS0.25Se0.75 exhibits the highest hole mobility (0.77 cm2·V-1·s-1) and a moderate photoresponsivity (4.44 × 102 A·W-1) with fast response speed (32.1/57.5 ms) under 635 nm irradiation. Furthermore, to reduce the dark current and strengthen the light absorption, a self-driven SnS0.25Se0.75/n-Si device has been fabricated. The device achieved a preeminent photo-responsivity of 377 mA·W-1, a detectivity of ~1011 Jones and Ilight/Idark ratio of ~4.5×102. In addition, the corresponding rising/decay times are as short as 4.7/3.9 ms. Moreover, a broadband sensitivity from 635 nm to 1200 nm is obtained and the related photoswitching curves are stable and reproducibility. Noticeably, the above parameters are comparable or superior to the most of reported group IVA layered materials-based self-driven photodetectors. Last, the synergistic effects between the SnS0.25Se0.75 nanosheets and the n-Si have been discussed by the band alignment. These brilliant results will pave a new pathway for the development of next generation 2D alloy-based photoelectronic devices.
关键词： alloy engineering,photodetectors,Tin chalcogenides,physical vapor deposition,van der Waals heterostructure
更新于2025-09-16 10:30:52
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Ultrahigh Stability 3D TI Bi <sub/>2</sub> Se <sub/>3</sub> /MoO <sub/>3</sub> Thin Film Heterojunction Infrared Photodetector at Optical Communication Waveband
摘要： Infrared (IR) detection at 1300–1650 nm (optical communication waveband) is of great significance due to its wide range of applications in commerce and military. Three dimensional (3D) topological insulator (TI) Bi2Se3 is considered a promising candidate toward high-performance IR applications. Nevertheless, the IR devices based on Bi2Se3 thin films are rarely reported. Here, a 3D TI Bi2Se3/MoO3 thin film heterojunction photodetector is shown that possesses ultrahigh responsivity (Ri), external quantum efficiency (EQE), and detectivity (D*) in the broadband spectrum (405–1550 nm). The highest on–off ratio of the optimized device can reach up to 5.32 × 104. Ri, D*, and the EQE can reach 1.6 × 104 A W?1, 5.79 × 1011 cm2 Hz1/2 W?1, and 4.9 × 104% (@ 405 nm), respectively. Surprisingly, the Ri can achieve 2.61 × 103 A W?1 at an optical communication wavelength (@ 1310 nm) with a fast response time (63 μs), which is two orders of magnitude faster than that of other TIs-based devices. In addition, the device demonstrates brilliant long-term (>100 days) environmental stability under environmental conditions without any protective measures. Excellent device photoelectric properties illustrate that the 3D TI/inorganic heterojunction is an appropriate way for manufacturing high-performance photodetectors in the optical communication, military, and imaging fields.
关键词： photodetectors,Bi2Se3 thin films,infrared optical communication wavebands,heterojunction structures,ultrafast response times
更新于2025-09-16 10:30:52
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Study of Electrophotophysical Characteristics of IR Photodetectors Based on PbS Colloidal Quantum Dots
摘要： The electrophotophysical characteristics of laboratory samples of IR photodetectors obtained by dip coating of PbS colloidal quantum dots with the subsequent exchange of oleic acid molecules that compose their ligand shell by S2? ions have been studied.
关键词： thin layers,electrophysical characteristics of layers,spectral and luminescent properties,dip-coating method,near infrared region,PbS colloidal quantum dots,ligand exchange,IR photodetectors
更新于2025-09-16 10:30:52
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Study of Metala??Semiconductora??Metal CH3NH3PbBr3 Perovskite Photodetectors Prepared by Inverse Temperature Crystallization Method
摘要： Numerous studies have addressed the use of perovskite materials for fabricating a wide range of optoelectronic devices. This study employs the deposition of an electron transport layer of C60 and an Ag electrode on CH3NH3PbBr3 perovskite crystals to complete a photodetector structure, which exhibits a metal–semiconductor–metal (MSM) type structure. First, CH3NH3PbBr3 perovskite crystals were grown by inverse temperature crystallization (ITC) in a pre-heated circulator oven. This oven was able to supply uniform heat for facilitating the growth of high-quality and large-area crystals. Second, the di?erent growth temperatures for CH3NH3PbBr3 perovskite crystals were investigated. The electrical, optical, and morphological characteristics of the perovskite crystals were analyzed by X-ray di?raction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy, and photoluminescence (PL). Finally, the CH3NH3PbBr3 perovskite crystals were observed to form a contact with the Ag/C60 as the photodetector, which revealed a responsivity of 24.5 A/W.
关键词： inverse temperature crystallization,MSM photodetectors,CH3NH3PbBr3 perovskite crystals,large-area crystals
更新于2025-09-16 10:30:52
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Chalcogenide || Lead salt photodetectors and their optoelectronic characterization
摘要： Lead salt photoconductors produced by chemical bath deposition are popular IR photodetectors due to their outstanding performance-to-cost ratio, high room temperature performance (D(cid:3) . 1E10) and availability of large area detectors. History of lead salt detectors has been reviewed recognizing some more recent research developments. The chemical bath deposition technique for production of the lead salt detectors has been outlined, followed by a review of the basics for their characterization. Spectral responses of both PbS and PbSe detectors collected in a wide temperature range and properly corrected have been presented.
关键词： PbSe,chemical bath deposition,photoconductors,Lead salt photodetectors,PbS,infrared spectral range
更新于2025-09-16 10:30:52