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Piezo-phototronic effect enhanced polarization-sensitive photodetectors based on cation-mixed organica??inorganic perovskite nanowires
摘要： Piezo-phototronic effect has been extensively investigated for the third generation semiconductor nanowires. Here, we present a demonstration that piezo-phototronic effect can even be applied to tune polarization-sensitive photodetectors based on cation-mixed organic–inorganic perovskite nanowires. A big anisotropic photoluminescence (PL) with linearly polarized light-excitation was found due to a strong spontaneous piezoelectric polarization besides the anisotropic crystal structure and morphology. The piezo-phototronic effect was utilized to tune the PL intensity, and an improved anisotropic PL ratio from 9.36 to 10.21 for linearly polarized light-excitation was obtained thanks to the modulation by piezo-potential. And a circularly polarization-sensitive PL characterized with circular dichroism ratio was also discovered, which was found to be modulated from 0.085 to 0.555 (with a 5.5-fold improvement) within the range of applied strain. The circular dichroism was resulted from the joint effects of the modulated Rashba spin–orbit coupling and the asymmetric carriers separation and recombination for right- and left-handed helicity due to the presence of effective piezo-potential. These findings not only reveal the promising optoelectronic applications of piezo-phototronic effect in perovskite-based polarization-sensitive photodetectors, but also illuminate fundamental understandings of their polarization properties of perovskite nanowires.
关键词： polarization-sensitive photodetectors,perovskite nanowires,Rashba spin–orbit coupling,Piezo-phototronic effect,photoluminescence
更新于2025-09-23 15:21:01
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High-performance amorphous BeZnO-alloy-based solar-blind ultraviolet photodetectors on rigid and flexible substrates
摘要： In this study, the bandgap of ternary alloy BeZnO was modulated to make the material applicable to solar-blind ultraviolet (UV) radiation detection. This was done by preparing amorphous films with high Be doping contents on rigid c-sapphire and flexible polyethylene terephthalate (PET) and polyethylene naphthalene (PEN) substrates. After depositing a pair of parallel Al electrodes, amorphous BeZnO-alloy-based solar-blind UV photodetectors (PDs) with peak responsivity occurring at around 230 nm were constructed and their cut-off wavelengths are less than 284 nm. The PDs constructed on three substrates exhibit extremely low dark currents of 58.7 pA, 2.9 pA, and 1.8 pA, respectively. Time-dependent photoresponse cycling confirmed devices reproducible, and sensitive to solar-blind UV radiation. More importantly, the devices exhibited fast response speeds with rise times of approximately 40 ms and particularly fast recovery speeds with decay times of approximately 10 ms. Our research provides a method of constructing high-performance PDs on various substrates. And constructing amorphous solar-blind UV PDs on flexible substrate in this work is expected to be guiding significance to the design of PDs with deformability.
关键词： Amorphous BeZnO alloy,Fast recovery speed,Solar blind photodetectors,Flexible substrate,High Be content
更新于2025-09-23 15:21:01
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Lead-free perovskite/organic semiconductor vertical heterojunction for highly sensitive photodetectors
摘要： In recent years, photodetectors based on organic-inorganic lead halide perovskites have been studied extensively. However, the inclusion of lead in those materials can cause severe human health and environmental problems, which is undesirable for practical applications. Here, we report high-performance photodetectors with a tin-based perovskite/PEDOT:PSS vertical heterojunction. The device demonstrates broadband photo-response from NIR to UV. The maximum responsivity and gain are up to 2.6 × 106 A/W and 4.7 × 106, respectively. Moreover, a much shorter response time and higher detectivity can be achieved by reducing the thickness of PEDOT:PSS. The outstanding performance is due to the excellent optoelectronic properties of the perovskite and the photo-gating effect originated from the heterojunction. Furthermore, devices fabricated on flexible substrates can demonstrate not only high sensitivity but also excellent bending stability. This work opens up the opportunity of using lead-free perovskite in highly sensitive photodetectors with vertical heterojunctions.
关键词： Photo-gating,heterojunction,organic semiconductors,Photodetectors,Lead free perovskites
更新于2025-09-23 15:21:01
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[IEEE 2018 23rd Opto-Electronics and Communications Conference (OECC) - Jeju Island, Korea (South) (2018.7.2-2018.7.6)] 2018 23rd Opto-Electronics and Communications Conference (OECC) - 2.8?μm infrared photodetectors based on PbSe colloidal quantum dot films
摘要： In this study, we synthesized monodisperse and high purity PbSe CQDs and then demonstrated the photodetectors working at different wavelengths up to 2.8 μm. Colloidal quantum dots (CQDs) have been studied extensively due to their attractive optoelectronic properties such as high luminescence efficiency, large dipole moment, strong light absorption, good photo-stability, and multiple electron hole pair generation. More importantly, the strong quantum confinement effect allows us to tailor the energy band gap of these materials by controlling their size in a cost-effective wet chemical synthesis. These advantages bring CdSe-based CQDs to a competitive market of lighting and display technology today. The research on lead based chalcogenide (PbTe, PbS, and PbSe) CQDs for infrared applications has also received much scientific and technological attention because of the possibility to tune the bandgap in the infrared wavelength range. Among lead based chalcogenide family, lead selenide (PbSe) CQDs have received more attention in not only photodetectors but also many infrared optoelectronic applications like solar cells, light emitting diodes, etc [1-4]. In the present work, we report about high performance photodetectors at a broad spectral range, for the first time, up to 2.8 μm based on our high quality, monodisperse PbSe CQDs. We deposited thin films of synthesized PbSe CQDs on the patterned interdigitated platinum electrodes by a drop casting method to create photodetectors. These photodetectors with different thicknesses of the PbSe CQD film were studied and optimized in detail for the best performance. The photocurrent responses were recorded as a function of bias voltage using infrared LED illuminations with wavelengths of up to 2.8 μm.
关键词： infrared photodetectors,detectivity,responsivity,PbSe colloidal quantum dots,photocurrent
更新于2025-09-23 15:21:01
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Surface Engineered Hybrid Corea??Shell Sia??Nanowires for Efficient and Stable Broadband Photodetectors
摘要： Silicon nanostructures have gained intensive interest to develop broadband photodetectors at a large-scale due to their excellent electronic properties. Herein, Si-nanowires (SiNWs) decorated with reduced graphene oxide:carbon quantum dots (rGO:CQDs) nanocomposite (NC), as core–shell heterojunction building blocks for broadband (ultraviolet (UV)–near infrared (NIR)) photodetectors (PDs), are demonstrated. The SiNWs and CQDs are synthesized by wet-chemical etching and facile pyrolysis methods, respectively. Photogenerated carriers are transported through rGO because of its high electron mobility and favorable band alignment with CQDs and Si. Further, to minimize the recombination of photogenerated carriers, and enhance the response in the visible region, plasmon-enhanced AuCQDs are incorporated in the shell matrix. The optimized heterostructure (rGO:AuCQDs/undoped CQDs/SiNWs) is sensitive to a broad wavelength range covering the UV to NIR (360 to 940 nm) region, manifests the excellent responsivity of 16 A W?1 at 360 nm, detectivity (D*) of 2.2 × 1013 Jones, and noise equivalent power as low as 2.8 fW Hz?1/2. The optimized PDs heterostructure demonstrates excellent air-stability after 8 days of illumination without any encapsulation or protective coating. The proposed simple, cost-effective, and Si-process-line compatible fabrication of Si-based PD device structure imposes a great promise for highly efficient and stable advanced futuristic optoelectronic devices.
关键词： core–shell heterostructure,detectivity,responsivity,broadband photodetectors,reduced graphene oxide,carbon quantum dots,Si nanowires
更新于2025-09-23 15:21:01
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Ultra-long high quality catalyst-free WO<sub>3</sub> nanowires for fabricating high-performance visible photodetectors
摘要： This work presents a study on the controlled growth of WO3 nanowires via chemical vapor deposition without catalyst, and their potential applications in visible photodetectors. The influence of growth conditions on the morphology of WO3 nanowires is studied in order to understand the growth mechanism of WO3 nanowires, and ultra-long (60 μm, the longest one ever reported) WO3 nanowires with a spindle shape are achieved by optimizing the growth conditions. The photoconductor detectors based on WO3 single nanowires present excellent device performance with a responsivity as high as 19 A/W at a bias of 0.1 V, a detectivity as high as 1.06 × 1011 Jones, and a response (rising and decay) time as short as 8 ms under the illumination of a 404 nm laser. These results indicate the great potential of WO3 nanowires for applications in fabricating high performance visible photodetectors.
关键词： visible light,high performance,photodetectors,chemical vapor deposition,WO3 nanowires
更新于2025-09-23 15:21:01
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Transparent, flexible MAPbI3 perovskite microwire array passivated with ultra-hydrophobic supramolecular assembly for stable and high-performance photodetectors
摘要： The emergence of organic-inorganic hybrid perovskites (OHPs) has revolutionised the potential performance of optoelectronic devices, most perovskites are opaque and hence incompatible with transparent optoelectronics, and sensitive to environmental degradation. Here, a single-step fabrication of ultra-long MAPbI3 perovskite microwire array over a large-area using stencil lithography based on a sequential vacuum sublimation. The environmental stability of MAPbI3 is empowered a newly designed and synthesized transparent supramolecular self-assembly, based on a mixture of two tripodal L-Phe-C11H23/C7F15 molecules, which showed a contact angle of 105° and served as ultra-hydrophobic passivation layer for more than 45 days in ambient atmosphere. The MAPbI3 microwire array passivated with supramolecular self-assembly demonstrate for the first time both excellent transparency of ~89% at 550 nm and remarkable photoresponse with photo-switching ratio of ~104, responsivity of 789 A/W, detectivity of 1014 Jones, linear dynamic range of ~ 122 dB, and rise time of 432 μs. Furthermore, the photodetector fabricated on flexible PET substrate demonstrated robust mechanical flexibility even beyond 1200 bending cycles. Therefore, the scalable stencil lithography and supramolecular passivation approaches have the potential to deliver next-generation transparent, flexible, and stable optoelectronics.
关键词： transparency,stencil lithography,photodetectors,MAPbI3,supramolecular self-assembly,flexibility,organic-inorganic hybrid perovskites,environmental stability
更新于2025-09-23 15:21:01
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Photogating-controlled ZnO photodetector response for visible to near-infrared light
摘要： Over the last several decades, as a direct wide band gap semiconductor, zinc oxide (ZnO) nanomaterial has attracted lots of attention. However, the widely investigated ZnO materials are strongly limited in fast-response and broadband photodetectors due to their inherent weaknesses, so effective structure or mechanism of ZnO nanostructure photodetector is urgent. In this work, a photogating-controlled photodetector based on ZnO nanosheet-HfO2-lightly doped Si architecture was demonstrated. Its performance was improved significantly by the photogating-controlled local field at Si and HfO2 interfaces compared to other published work of ZnO. Consequently, the photodetector not only effectively balance the responsivity (as high as 5.6 A W-1) and response time (400 μs), but also broadens the response wavelength of the ZnO-based photodetectors from visible to near-infrared (~1200 nm). Additionally, the photogating-controlled ZnO photodetector enables high-resolution imaging both in visible and near-infrared bands. Our photogating-controlled ZnO photodetectors not only exemplify the control ability of the gate electrode in high mobility materials but also provide ideas for fast speed and high responsivity detection of high mobility materials.
关键词： ZnO nanosheet,photogating-controlled photodetectors,response wavelength,high-resolution imaging
更新于2025-09-23 15:21:01
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Laser-Induced Optoelectronic and Crystallographic Tuning of Methyl Ammonium Iodobismuthate Perovskite for Improved Performance of Sandwiched a?? Type Photodetectors
摘要： Towards development of high-performance perovskite based photodetectors, it is required that optical and crystallographic properties of perovskites materials be enhanced through perovskites materials modification. Many attempts on this quest result in alteration of chemical structure of perovskites materials through introduction of dopants. Here in, we present a clean and structural preservative technique of tuning optical and crystallographic properties of bismuth based lead free perovskite materials through irradiation with 2.5 mJ laser pulses ejected from Nd:YAG LASER operating in its second harmonics. XRD spectra show improved crystallinity and reduced crystallite size, SEM images show defect – minimized surface morphology, PL spectra show minimized rate of Auger recombination and absorbance spectra show improved absorbance at a constant band gap value. Consequently, simplified sandwiched architectural type photodetectors fabricated with the modified bismuth based perovskite materials display maximum photodetectivity of 4.5 × 109 Jones, maximum photoresponsivity of 25 μA/W, maximum photosensitivity of about 104 and minimum optical switching times of 10 ms under testing conditions of -2 V bias voltage, 15 mW/cm2 incident solar light and room temperature. Thus, laser pulses irradiation presents an alternative method of enhancing optical and crystallographic properties of perovskite materials from which highly efficient classes of photonics and photovoltaic devices can be developed.
关键词： Laser Irradiation,crystallographic properties,optical properties,perovskite photodetectors,lead free perovskites materials
更新于2025-09-23 15:21:01
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Colloidal Quantum-Dots/Graphene/Silicon Dual-Channel Detection of Visible Light and Short-Wave Infrared
摘要： Integration of infrared detectors with current silicon-based imagers would not only extend their spectral sensing range but also enables numerous applications including thermal imaging, machine vision, and spectrometers. Here, we report the development of a dual-channel photodetector by depositing a colloidal quantum dot (CQDs) infrared photodiode onto a graphene/p-Silicon Schottky diode to provide simultaneous visible and infrared photoresponse channels. The HgTe photodiode is patterned into a semitransparent mesh-structure so that the visible light reaches the Silicon substrate with varying fill factors. The graphene/silicon Schottky junction has a responsivity of ~0.9 A/W in the visible and the infrared CQDs photodiode has a detectivity of ~5×109 Jones at 2.4μm, for a filling factor of 0.1.
关键词： Photodetectors,Graphene/silicon Schottky junction,Visible/infrared,Colloidal quantum dots
更新于2025-09-23 15:21:01