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Preparation of visible-enhanced PbI2/MgO/ Si heterojunction photodetector
摘要： Fabrication and characterization of p-PbI2/MgO/n-Si photodetectors by pulsed laser deposition within (2.7-2.5) eV. The current-voltage and capacitance-voltage properties of PbI2/MgO/Si photodetector were investigated. The best responsivity of p-PbI2/MgO/n-Si photodetectors was ~ investigated using x-ray diffraction XRD, UV-Vis absorption and scanning electron microscope SEM. The XRD results revealed a single crystalline MgO with cubic structure along the (200) PLD under different deposition temperatures Ts were demonstrated for the first time. Structural, optical and morphological properties of nanostructured MgO and PbI2/MgO films were plane, while the PbI2 film deposited on MgO was a single crystalline with hexagonal phase along (001) plane. The optical energy gaps of PbI2 films deposited on MgO film were found to be perovskite solar cells, photodetectors, X-ray detectors, photoconductors, biological labeling and diagnostics, active matrix flat panel imagers, and γ-ray detectors [3, 4]. PbI2 films are usually prepared thermal evaporation, chemical methods, pulsed laser deposition, atomic layer deposition, and electron beam evaporation [5-8]. The wider optical energy gap MgO (7.3 eV at room temperature) is a non-toxic, high specific surface reactivity and cubic crystal structure with Fm-3m space group and transparent at the visible light. MgO films have been used in many [1, 2]. Lead iodide has been used in numerous applications, for example, light emitting diodes, Lead iodide has a hexagonal structure with optical band gap around 2.2eV at room temperature Keywords: PbI2; MgO; PLD; Heterojunction; Silicon; photodetector; Deposition temperature 0.88A/W at 410nm when the photodetector was prepared at Ts = 45°C.
关键词： Silicon,photodetector,MgO,Deposition temperature,PbI2,Heterojunction,PLD
更新于2025-09-11 14:15:04
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Template-Confined Growth of Ruddlesden-Popper Perovskite Micro-Wire Arrays for Stable Polarized Photodetectors
摘要： The detection of the polarization states of light is of great significance for analysis of biological tissue morphology, image display systems and sensors. Although organic-inorganic hybrid perovskite crystals have excellent photoelectric properties which make them very suitable for the preparation of photodetectors, their application for polarized light detection are hindered by their isotropy and instability. Here, we solved this problem by fabricating stable 2D layered Ruddlesden-Popper perovskite into anisotropic micro-wire arrays with a template-confined method. Based on this anisotropic structure, high performance photodetector with dark current as low as 10-12 A, high responsivity of 3.5 AW-1，detectivity exceeding 1×1015 Jones and fast response time of 4.1 ms for rising and 3.3 ms for decay had been achieved and successfully applied to high-performance polarization detection. More importantly, the device maintained superior performance even after being exposured in an environment of a relative humidity of 60% without encapsulation.
关键词： perovskite,micro-wire arrays,template-confined growth,photodetector,polarization detection
更新于2025-09-11 14:15:04
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Self‐Polarized BaTiO <sub/>3</sub> for Greatly Enhanced Performance of ZnO UV Photodetector by Regulating the Distribution of Electron Concentration
摘要： ZnO film ultraviolet photodetectors (UV PDs) have always suffered from slow speed and low photosensitivity that restrict their broader applications. To break through those barriers, high-performance ZnO UV PD based on self-polarized BaTiO3 (BTO) is first introduced through a facile one-step spin-coating method. Compared with pure ZnO film UV PD with low on/off ratio (65) and slow speed (4.1/7.5 s) at 3 V bias under 350 nm UV light, the BTO-ZnO bilayer film device exhibits an ultrahigh on/off ratio (14 300) and ultrafast response speed (0.11/5.80 ms), which is much faster than that of the most reported ZnO film-based UV PDs. The numerical simulation demonstrates that the spatial distribution of electron concentration of ZnO film is regulated by the self-polarization of BTO film, resulting in low dark current and fast response time of the BTO-ZnO PD. This work provides a new approach to fabricate high-performance PDs based on self-polarized ferroelectric materials.
关键词： ZnO film,self-polarization,UV photodetector,BaTiO3 film
更新于2025-09-11 14:15:04
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Dual-Polarity Response in Self-Powered ZnO NWs/Sb2Se3 Film Heterojunction Photodetector Array for Optical Communication
摘要： Self-powered photodetectors (PD) have great potential applications in visible light communication (VLC) systems due to their unique advantages such as energy saving and low cost, where color shift keying (CSK) is widely utilized to meet the requirements of non-negative light intensity modulation. However, at least two PDs with filters are needed to decode the optical signals, greatly increasing the device cost and complicating the communication system. Here, we report a new type of dual-polarity response PD with an adjustable polarity switching wavelength, where the output signals are positive and negative in long and short wavelength regions, respectively. The dual-polarity response is a consequence of the competition between photovoltaic (PV) effect of ZnO NWs/Sb2Se3 film p-n junction and pohtothermoelectric (PTE) effect of Sb2Se3 thin film. As compared with current PDs in CSK systems, our PD can work without any filter and one PD can realize the function of two traditional PDs. This new PDs have the potential applications in optical communication systems and filterless color discrimination.
关键词： Photodetector,ZnO,self-powered,Sb2Se3,dual-polarity
更新于2025-09-11 14:15:04
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Metamaterial grating-integrated graphene photodetector with broadband high responsivity
摘要： Graphene has some outstanding properties in the photoelectric field, especially ultra fast response and broad spectrum absorption, which have led to strong attraction on graphene photodetector. However, the photo-responsivity of pure graphene device is below 10 mA W?1. It would limit the application of graphene photodetector. Here, we design a metamaterial structure with a broadband high absorption spectrum. And by integrating it into the graphene photodetector, the high photoresponsivity of a pure graphene photodetector in a broadband range could be acquired. The photoresponsivity of photodetector can achieve nearly 200 mA W?1, which is two orders higher than the one of pure monolayer graphene photodetector. Besides, the photodetector also keeps the broadband photoresponse. The hot carriers can be generated by coupling of multiple resonances and effectively transported to graphene with the advantage of ultrathin metal film. Based on this work, more potential applications of graphene photodetector could be developed in some related fields.
关键词： Metamaterial,Graphene,Photodetector,Photoresponsivity
更新于2025-09-11 14:15:04
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Layer-Dependent Properties of Ultrathin GeS Nanosheets and Application in UV-vis Photodetector
摘要： Two-dimensional germanium sulfide (GeS), an analogous of phosphorene, has attracted broad attention owing to its excellent environmental stabilities, fascinating electronic, optical properties and applications in various nanodevices. In spite of the current achievements on 2D GeS, the report of ultrathin few-layer GeS nanosheets within 5 nm are still lack. Here in this contribution, we have achieved preparation of ultrathin few-layer GeS nanosheets with thicknesses of 1.3 ± 0.1 nm (~3L), 3.2 ± 0.2 nm (~6L) and 4.2 ± 0.3 nm (~8L) via typical liquid phase exfoliation (LPE) method. Based upon various experimental characterizations and first principles calculations, the layer-dependent electronic, transport and optical properties are investigated. For the few-layer GeS nanosheets, enhanced light absorption in UV-vis region and superior photoresponse behavior with increasing layer number is observed, while for the thin films above 10 nm, the properties degenerate to the bulk feature. In addition, the as-prepared ultrathin nanosheets manifest great potential in the applications of photoelectrochemical (PEC)-type photodetectors, exhibiting excellent and stable periodic photoresponse behavior under the radiation of white light. The ~8L-GeS based photodetector performs superior performance than the thinner GeS nanosheets (<4 nm), even better as compared to the bulk or film (above 10 nm) counterparts, in terms of higher photoresponsivity along with remarkable photodetection performance in the UV-vis region. This work not only provides direct and solid evidence of layer-number evolutional band structure, mobility and optical properties of ultrathin 2D GeS nanosheets, but also promotes the foreseeable applications of 2D GeS as energy-related photoelectric devices.
关键词： photoresponse performance,layer-dependent property,2D material,few-layer GeS,photodetector
更新于2025-09-11 14:15:04
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Two-Dimensional Covalent Organic Framework–Graphene Photodetectors: Insight into the Relationship between the Microscopic Interfacial Structure and Performance
摘要： Graphene is an attractive material for photodetection and optoelectronic applications because it offers a broad spectral bandwidth and ultrafast response speed. However, because of the broad light absorption characteristic, graphene has a lack of selectivity to the wavelength, which limits the performance of graphene-based photodetectors. Here, we demonstrate a novel hybrid photodetector with monolayer graphene covered with an ultrathin film of surface covalent organic frameworks (COFs) with variable structures as the light-harvesting materials. Photodetectors based on surface COF?G show enhanced responsivity in comparison with unmodified graphene and graphene modified with monomers. The submolecular resolution of scanning tunneling microscopy allows us to get a direct insight into the relationship between the microscopic interfacial structure and the performance of the device. We prove that the enhancement in the device performance is directly related with the orderliness of surface COFs, which influences the interfacial charge transfer by tuning π?π stacking between surface COF and graphene.
关键词： covalent organic frameworks,photodetector,charge transfer,interfacial structure,graphene
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - First Principles Investigation into Graphene-PbSe MidWave IR (MWIR) Photodetector Physics
摘要： Polycrystalline PbSe is an established low cost material for mid wave-IR photodetection. In this work, we describe a novel design of PbSe MWIR detector that incorporates a graphene layer resulting in three possible distinct modes of operation, depending on the interface design between the functionalized PbSe and Graphene. Using Density Functional Theory (DFT) based simulations we investigate the chemistry of this interface, in terms of back-bonding as well as van-der Waals force, that give rise to rich behavior that is obtainable from this material stack, promising radical new designs for scaled high performance CMOS integrable MWIR photodetectors.
关键词： Photodetector,Graphene,PbSe,Mid-Wave IR,Density Functional Theory
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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SnS <sub/>2</sub> quantum dots: Facile synthesis, properties, and applications in ultraviolet photodetector
摘要： Tin sulfide quantum dots (SnS2 QDs) are n-type wide band gap semiconductor. They exhibit a high optical absorption coefficient and strong photoconductive property in the ultraviolet and visible regions. Therefore, they have been found to have many potential applications, such as gas sensors, resistors, photodetectors, photocatalysts, and solar cells. However, the existing preparation methods for SnS2 QDs are complicated and require a high temperature and high pressure environments; hence they are unsuitable for large-scale industrial production. An effective method for the preparation of monodispersed SnS2 QDs at normal temperature and pressure will be discussed in this paper. The method is facile, green, and low-cost. In this work, the structure, morphology, optical, electrical, and photoelectric properties of SnS2 QDs are studied. The synthesized SnS2 QDs are homogeneous in size and exhibit good photoelectric performance. A photoelectric detector based on the SnS2 QDs is fabricated and its J–V and C–V characteristics are also studied. The detector responds under λ = 365 nm light irradiation and reverse bias voltage. Its detectivity approximately stabilizes at 1011 Jones at room temperature. These results show the possible use of SnS2 QDs in photodetectors.
关键词： photodetector,photoelectric properties,quantum dots,SnS2
更新于2025-09-11 14:15:04