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Highly flexible self-powered photodetectors based on core–shell Sb/CdS nanowires
摘要： Flexible photodetectors have great applications in flexible image sensors, wearable electronics and smart robots. In this work, we reported the fabrication of highly flexible self-powered photodetectors with core-shell Sb/CdS nanowires as the sensing materials. The fabricated device exhibited high Ion/Ioff ratio of 3.54×103 under zero bias, fast speed of photoresponse and great stability. An open-circuit voltage of 0.35 V was generated due to the presence of CdS and CdSb interfaces within the core-shell nanowires. Besides, the photocurrent of the flexible device is nearly invariable at various bending angles and even after thousands of bending cycles, demonstrating the excellent flexibility and bending stability. The results indicated that the self-powered photodetectors are promising candidates for future passive optoelectronic devices.
关键词： core-shell Sb/CdS nanowires,optoelectronic devices,self-powered,flexible photodetectors
更新于2025-11-21 11:03:13
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High-responsivity Two-dimensional p-PbI <sub/>2</sub> /n-WS <sub/>2</sub> Vertical Heterostructure Photodetectors Enhanced by Photogating Effect
摘要： Two-dimensional (2D) vertical p-n heterostructure photodetectors are significant building blocks in nanoscale integrated optoelectronics. However, the unsatisfactory photosensing performance combined with complicated fabrication process still remains a challenge. In this work, the fabrication of high performance vertical photodetectors based on vapor grown p-PbI2/n-WS2 heterostructures is reported, in which the WS2 serves as the photogate to modulate the channel current. Due to the photogating effect in the heterostructures, the recombination of photo-excited electron–hole pairs is effectively suppressed, leading to high photoresponsivity up to 5.57 × 102 A W-1, which represents the highest value among the ever reported vapor-grown vertical p-n heterostructures. Moreover, the photoresponsivity is highly tunable through the gate voltage bias, and can be further improved to 7.1 × 104 A W-1 by applying a negative gate voltage bias of -60 V. The excellent photosensing properties of the PbI2/WS2 heterostructures combined with the facile synthesis method suggest a great potential in developing high performance 2D optoelectronic devices.
关键词： vertical p-n heterostructure,photogating effect,vapor deposition,photodetectors,Two-dimensional
更新于2025-11-14 17:04:02
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High-performance flexible UV photodetectors based on AZO/ZnO/PVK/PEDOT:PSS heterostructures integrated on human hair
摘要： Flexible optoelectronics is an emerging research field that has attracted profound interest in recent years due to the special functions and potential applications of these devices in flexible image sensors, optical computing, energy conversion devices, Internet of Things and other technologies. Here, we demonstrate the high-performance UV photodetectors using AZO/ZnO nanorods/PVK/PEDOT:PSS heterostructures integrated on human hair. Due to the precise interfacial energy-level alignment among all layers and superior mechanical characteristics of human hair, the as-obtained photodetector shows a fast response time, high photoresponsivity and excellent flexibility. According to integrate 7 heterostructures as 7 display pixels, the flexible UV-image sensor has superior device performance and outstanding flexibility and can produce vivid and accurate images of Arabic numerals from 0 to 9. Different combinations of the two heterostructures can also be used to achieve flexible photon-triggered logic functions including AND, OR and NAND gates. The findings in this work indicate the possibility of using the human hair as fibre-shaped flexible substrate and will allow the use of hair-based hierarchical heterostructures as building blocks to create exciting opportunities for next generation high-performance, multifunctional, low-cost, and flexible optoelectronic devices.
关键词： photon-triggered logic gates,fast photoresponse,UV photodetectors,human hair,optical-image sensors
更新于2025-11-14 17:04:02
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Power- and Spectral-Dependent Photon-Recycling Effects in a Double-Junction Gallium Arsenide Photodiode
摘要： Photon recycling effects improve radiative efficiencies of semiconductor materials, and play important roles in the design of high performance optoelectronic devices. Conventional research mostly studies the impact of photon recycling on the voltage of photodiodes. Here we systematically analyze the photon response of a microscale gallium arsenide (GaAs) based double junction photodiode. In such a device, the current matching condition between two subcells is determined by their photon coupling. Photodynamics in the device is examined and reveals the material’s internal quantum efficiencies. By leveraging photon distributions inside the device, we discover that its photocurrent and spectral responses are highly dependent on the illumination intensity. Consistent with theoretical analyses, the device’s photocurrents exhibit linear and superlinear power dependent characteristics under near-infrared and violet-blue illuminations, respectively. Due to strongly enhanced photon recycling effects under strong illumination, broadband photon responses (external quantum efficiency close to 50% from 400 nm to 800 nm) could be achieved in such a strongly current mismatched GaAs dual junction device. The understanding of photon processes in such devices would offer routes to the design of high-performance photodetectors and solar cells.
关键词： photovoltaics,photodetectors,gallium arsenide,photon recycling,multijunction
更新于2025-09-23 15:23:52
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Influence of Cr doping on Schottky barrier height and visible light detection of ZnO thin films deposited by magnetron sputtering
摘要： A comparative study of the electrical and photodetection properties of ZnO and Cr doped ZnO thin films are being reported here. The films were deposited using magnetron sputtering. X-ray diffraction (XRD) revealed hexagonal crystal structure of the films with (002) preferred orientation. Pt/ZnO/Pt and Pt/Cr doped ZnO/Pt Schottky diodes were fabricated for photodetection studies. The Schottky barrier height was lowered for Cr doped ZnO film as compared to ZnO film. The ideality factor was improved upon Cr doping. Pt/ZnO/Pt diode was unresponsive to visible light, however, Pt/Cr doped ZnO/Pt diode showed response to visible light with short response and recovery times. The response of the Pt/Cr doped ZnO/Pt diodes to visible light is attributed to the reduction in band gap of the Cr doped ZnO thin film.
关键词： Thin films,Schottky contact,Chromium-doped Zinc oxide,Sputtering,Photodetectors
更新于2025-09-23 15:23:52
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New modeling method for UV sensor photoelectrical parameters extraction
摘要： In this work, we have developed a new modeling tools based on physical, mathematical and numerical models for the analysis of UV-photodetectors based on ZnO NRs/PPV-C6 hybrid heterojunctions. The photoelectrical equivalent circuit parameters are the series resistance (Rs), the shunt resistance (Rp), the reverse current density (J0), the ideality factor (n) and the photocurrent density (Jph). A combined physical-mathematical-numerical approach based on the modified Schockley model, the Lambert W function and the optimized method of the Root Mean Square error (RMSE) was applied to analyze the different devices performances. The results demonstrate that the incorporation of PPV-C6 polymer to the ZnO NRs structure leads to significant amelioration in the interface and increase of both the Jph and responsivity with a decrease of the Rs. This kind of hybrid heterojunction based UV light sensor is promising for future low cost and high performance optoelectronic devices development.
关键词： Photodetectors,Hybrid heterojunction,UV sensor,Modeling,Photoelectrical properties
更新于2025-09-23 15:23:52
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WaterSpy: A High Sensitivity, Portable Photonic Device for Pervasive Water Quality Analysis
摘要： In this paper, we present WaterSpy, a project developing an innovative, compact, cost-effective photonic device for pervasive water quality sensing, operating in the mid-IR spectral range. The approach combines the use of advanced Quantum Cascade Lasers (QCLs) employing the Vernier effect, used as light source, with novel, fibre-coupled, fast and sensitive Higher Operation Temperature (HOT) photodetectors, used as sensors. These will be complemented by optimised laser driving and detector electronics, laser modulation and signal conditioning technologies. The paper presents the WaterSpy concept, the requirements elicited, the preliminary architecture design of the device, the use cases in which it will be validated, while highlighting the innovative technologies that contribute to the advancement of the current state of the art.
关键词： Quantum Cascade Lasers,photonics,water quality monitoring,photodetectors
更新于2025-09-23 15:22:29
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Bandgap engineering in CuO nanostructures: Dual-band, broadband, and UV-C photodetectors
摘要： In this work, the bandgap of CuO (p-type semiconductor) has been engineered from an indirect bandgap of (cid:2)1 eV to a direct bandgap of 4 eV just by tuning the nanostructure morphology and midgap defect states. The absorption in near-infrared (NIR) and visible regions is ordinarily suppressed by controlling the growth parameters. Considering the increasing scope and demand of varying spectral range (UV-C to NIR) photodetectors, the systematic variation of the available density of states (DOS) at a particular energy level in CuO nanostructures has been utilized to fabricate dual-band (250 nm and 900 nm), broadband (250 nm–900 nm), and UV-C (250 nm) photodetectors. The sensitivity and detectivity of the photodetector for broadband detectors were (cid:2)103 and 2.24 (cid:3) 1011 Jones for the wavelengths of 900 nm and 122 and 2.74 (cid:3) 1010 Jones for 250 nm wavelength light, respectively. The UV-C detector showed a sensitivity of 1.8 and a detectivity of 4 (cid:3) 109 Jones for 250 nm wavelength light. A plausible mechanism for the photoconduction has been proposed for explaining the device operation and the effect of variation in available DOS. The obtained photodetectors are the potential candidates for future optoelectronic applications.
关键词： Broadband photodetectors,Bandgap engineering,CuO nanostructures,Dual-band photodetectors,UV-C photodetectors
更新于2025-09-23 15:21:01
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[IEEE 2019 3rd International Conference on Circuits, System and Simulation (ICCSS) - Nanjing, China (2019.6.13-2019.6.15)] 2019 3rd International Conference on Circuits, System and Simulation (ICCSS) - Research on Deep-UV Photodetectors Based on Carbon Dots as Reactive Layer
摘要： Deep-ultraviolet photodetectors are attracting attention due to their important applications in various fields. In this paper, carbon dots are used as an active layer to fabricate DUV photodetectors. These devices are capable of detecting UV light at wavelengths below 320 nm. Carbon dots are prepared by electrochemical method using distilled water as the electrolyte and their properties were characterized. A planar photoconductive structure is designed using carbon dots as reactive layer to prepare effective device by processes such as thermal evaporation and the performance of the device was estimated. The results show that the absorption peak of the carbon dots prepared by the electrochemical method is around 230 nm. A photodetector fabricated with carbon dots as an active layer has a good response at 254 nm illumination and the ratio of photocurrent to dark current of the device reaches 188.
关键词： wide bandgap,deep ultraviolet,carbon dots,photodetectors
更新于2025-09-23 15:21:01
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Ultra-wide-bandgap (ScGa)2O3 alloy thin films and related sensitive and fast responding solar-blind photodetectors
摘要： Although b-Ga2O3 is considered an excellent candidate for solar-blind photodetectors (PDs) owing to its direct bandgap (4.9 eV) and high stability, the cut-off wavelength often oversteps the DUV region, reducing the rejection ratio of the PD. Moreover, oxygen vacancies, which always appear in b-Ga2O3 ?lms, act as trap centers hindering carrier recombination and signi?cantly lowering response speed. To disentangle these issues, we propose in this work to modify b-Ga2O3 by incorporating Sc to form ternary (ScGa)2O3 alloys. Thanks to the wider bandgap of Sc2O3 (~5.7 eV) than Ga2O3 and stronger SceO bonding than GaeO, the (ScGa)2O3 alloy ?lms exhibit a wider bandgap (5.17 eV) with fewer oxygen vacancies compared with pure-Ga2O3, as expected, which eventually lead to an ultra-low dark current (0.08 pA at 10 V) and faster response times (trise: 41/149 ms; tdecay: 22/153 ms) of the alloy ?lm-based PDs. Furthermore, the peak and cut-off response wavelengths of the (ScGa)2O3 PD are blue shifted relative to the pure Ga2O3 PD, resulting in a higher rejection ratio (>500 vs ~317). The Sc-alloying strategy, taking advantage of wider bandgap of Sc2O3 and stronger SceO bonding to widen the bandgap while reducing the intrinsic carriers and oxygen vacancies in the (ScGa)2O3 alloy, is expected to be generally applicable to the design of other wide-bandgap oxide alloys for developing high-performance UV photodetectors with a low dark current and high response speed.
关键词： Ga2O3 thin ?lms,Pulsed laser deposition,Solar-blind photodetectors,Sc-alloying
更新于2025-09-23 15:21:01