- 标题
- 摘要
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- 实验方案
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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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Spatiotemporal Adaptive Nonuniformity Correction Based on BTV Regularization
摘要： The residual nonuniformity response, ghosting artifacts, and over-smooth effects are the main defects of the existing nonuniformity correction (NUC) methods. In this paper, a spatiotemporal feature-based adaptive NUC algorithm with bilateral total variation (BTV) regularization is presented. The primary contributions of the innovative method are embodied in the following aspects: BTV regularizer is introduced to eliminate the nonuniformity response and suppress the ghosting effects. The spatiotemporal adaptive learning rate is presented to further accelerate convergence, remove ghosting artifacts, and avoid over-smooth. Moreover, the random projection-based bilateral filter is proposed to estimate the desired target image more accurately which yields more details in the actual scene. The experimental results validated that the proposed algorithm achieves outstanding performance upon both simulated data and real-world sequence.
关键词： infrared image sensors,Infrared imaging,neural networks,image denoising
更新于2025-09-23 15:23:52
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[Advances in Intelligent Systems and Computing] Advanced Computing and Systems for Security Volume 883 (Volume Eight) || Remote Sensing Technology for Evaluation of Variations in Land Surface Temperature, and Case Study Analysis from Southwest Nigeria
摘要： Recent studies have shown that evaluation of the changes in the Land Surface Temperature (LST) of any area can be a re?ector of changes in urbanisation trend, industrial activities, population change and natural factors. Subsequently, many researches have evolved over time, especially with development in remote sensing, digital image processing and geographical information systems. This chapter is aimed at providing information on the relevance and challenges of remote sensing as a geospatial technology that is capable of being used for monitoring LST at different spatial and timescales. The case study analysis indicated that the results from the remote sensing processing of the imageries re?ect signi?cant in?uence of the spatial resolutions of selected imageries. The challenges of huge image data gaps, cloud cover, coarse spatial and temporal resolution, limited night-time data for evaluation of night-time urban heat island—for both technical and security reasons, in?uenced the reliability of the study results. The study recommended policies for improvement in the applications and utilisation of the geospatial technology in many developing countries, including Nigeria based on its strengths.
关键词： Nigeria,Image sensors,Land surface temperature,Image analysis
更新于2025-09-23 15:22:29
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Digital Circuit Methods to Correct and Filter Noise of Nonlinear CMOS Image Sensors
摘要： Nonlinear complementary metal-oxide semiconductor (CMOS) image sensors (CISs), such as logarithmic (log) and linear–logarithmic (linlog) sensors, achieve high/wide dynamic ranges in single exposures at video frame rates. As with linear CISs, fixed pattern noise (FPN) correction and salt-and-pepper noise (SPN) filtering are required to achieve high image quality. This paper presents a method to generate digital integrated circuits, suitable for any monotonic nonlinear CIS, to correct FPN in hard real time. It also presents a method to generate digital integrated circuits, suitable for any monochromatic nonlinear CIS, to filter SPN in hard real time. The methods are validated by implementing and testing generated circuits using field-programmable gate array (FPGA) tools from both Xilinx and Altera. Generated circuits are shown to be efficient, in terms of logic elements, memory bits, and power consumption. Scalability of the methods to full high-definition (FHD) video processing is also demonstrated. In particular, FPN correction and SPN filtering of over 140 megapixels per second are feasible, in hard real time, irrespective of the degree of nonlinearity.
关键词： FPGA,salt-and-pepper noise,digital circuits,real-time processing,fixed pattern noise,CMOS image sensors
更新于2025-09-23 15:22:29
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<i>(Invited)</i> Proximity Gettering Design of Hydrocarbon Molecular Ion Implanted Silicon Wafers Using Direct Bonding Technique for Advanced CMOS Image Sensors: A Review
摘要： We developed high gettering capability silicon wafers for advanced CMOS image sensors using hydrocarbon molecular ion implantation and surface activated direct wafer bonding (SAB). We found that this novel wafer has three unique characteristics for the improvement of CMOS image sensor device performance. The first is metallic impurity gettering capability in the hydrocarbon ion implantation projection range during CMOS device fabrication. The second is the oxygen out-diffusion barrier effect; this wafer can control out-diffusion to the device active region from the CZ grown silicon substrate during CMOS device heat treatment. The third is the hydrogen passivation effect; hydrogen passivates to the Si/SiO2 gate oxide interface state defects which out-diffuse to the device active region from the hydrocarbon ion implantation projection range during the CMOS device fabrication. Moreover, we demonstrated that this novel wafer can improve the pn-junction leakage current under the actual device fabrication.
关键词： CMOS image sensors,hydrocarbon molecular ion implantation,surface activated direct wafer bonding,gettering capability,oxygen out-diffusion barrier,hydrogen passivation
更新于2025-09-23 15:21:21
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Radiation Hardness Comparison of CMOS Image Sensor Technologies at High Total Ionizing Dose Levels
摘要： The impact of the manufacturing process on the radiation induced degradation effects observed in CMOS image sensors at the MGy total ionizing dose levels is investigated. Moreover, the vulnerability of the partially pinned photodiodes at moderate to high total ionizing doses is evaluated for the first time to our knowledge. It is shown that the 3T standard partially pinned photodiode has the lowest dark current before irradiation, but its dark current increases to ~1 pA at 10 kGy(SiO2). Beyond 10 kGy(SiO2), the pixel functionality is lost. The comparison between several CIS technologies points out that the manufacturing process impacts the two main radiation induced degradations: the threshold voltage shift of the readout chain MOSFETs and the dark current increase. For all the tested technologies, 1.8V MOSFETs exhibit the lower threshold voltage shift and the N MOSFETs are the most radiation tolerant. Among all the tested devices, 1.8V sensors achieve the best dark current performance. Several radiation-hard-by-design solutions are evaluated at MGy level to improve further the understanding of CIS radiation hardening at extreme total ionizing dose.
关键词： Gate Overlap,Radiation Effects,Drain,CMOS Image sensors,Partially Pinned Photodiode,Dark Current,TID,Threshold shift,RHBD
更新于2025-09-23 15:21:01
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Analysis and Design of a CMOS Ultra-High-Speed Burst Mode Imager with In-Situ Storage Topology Featuring In-Pixel CDS Amplification
摘要： This paper presents an in-situ storage topology for ultra-high-speed burst mode imagers, enabling low noise operation while keeping a high frame depth. The proposed pixel architecture contains a 4T pinned photodiode, a correlated double sampling (CDS) amplification stage, and an in-situ memory bank. Focusing on the sampling noise, the system level trade-off of the proposed pixel architecture is discussed, showing its advantages on the noise, power, and scaling capability. Integrated with an AC coupling CDS stage, the amplification is obtained by exploiting the strong capacitance to the voltage relation of a single NMOS transistor. A comprehensive noise model is developed for optimizing the trade-off between the area and noise. As a proof-of-concept, a prototype imager with a 30 μm pixel pitch was fabricated in a CMOS 130 nm technology. A 108-cell memory bank is implemented allowing dense layout and parallel readout. Two types of CDS amplification stages were investigated. Despite the limited memory capacitance of 10 fF/cell, the photon transfer curves of both pixel types were measured over different operation speeds up to 20 Mfps showing a noise performance of 8.4 e?.
关键词： burst mode,million frames per second,ultra-high-speed imaging,in-pixel amplification,in-situ storage,image sensors
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia) - Chengdu, China (2019.5.21-2019.5.24)] 2019 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia) - Designs and Applications for the Controller Parameters of the Photovoltaic System
摘要： Many economically important minerals have absorption features in the short-wave infrared (SWIR; 2000–2500 nm). Sensors which measure this part of the spectrum cannot detect the wavelength minimum of a feature at ～900 nm (F900), indicative of ferric iron mineralogy. A method based on Gaussian processes (GPs) was developed and compared with multiple linear regression (MLR) to estimate the wavelength position of F900 from SWIR data (1002–1355 nm). SWIR data with different signal-to-noise ratios were acquired from crushed rock samples by a nonimaging spectrometer and an imaging spectrometer. GP estimates of wavelength position were converted to the proportion of goethite using coefficients from a regression of the proportion of goethite determined from X-ray diffraction (XRD) on wavelength position measured directly from spectra. GP-estimated wavelength positions were within the 2-nm and ～4-nm root-mean-square error of measurements made directly from spectra for nonimaging and imaging spectrometer data, respectively. Proportions of goethite derived from these estimates were respectively within 4% and 6% of the values measured by XRD. MLR performed poorly compared to GPs when applied to data with no added noise and failed when applied to data with added noise or to imaging spectrometer data. These findings indicate that the wavelength position of F900—an indicator of ferric iron mineralogy—can be estimated from data acquired at SWIR wavelengths (1002–1355 nm). This opens up possibilities for using a single (SWIR) sensor to acquire information on ferric iron mineralogy (using F900) and other minerals with diagnostic absorptions between 1000 and 2500 nm.
关键词： geology,infrared spectroscopy,iron,image sensors,remote sensing,Gaussian processes (GPs),mining industry,Electromagnetic radiation,spectral analysis,signal processing
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Evaluation of Carrier Trapping in SiN <sub/>x</sub> Towards Ion Migration Measurements
摘要： A low temporal read noise and high conversion gain reset-gate-less CMOS image sensor (CIS) has been developed and demonstrated for the first time at photoelectron-counting-level imaging. To achieve a high pixel conversion gain without fine or special processes, the proposed pixel has two unique structures: 1) coupling capacitance between the transfer gate and floating diffusion (FD) and 2) coupling capacitance between the reset gate and FD, for removing parasitic capacitances around the FD node. As a result, a CIS with the proposed pixels is able to achieve a high pixel conversion gain of 220 μV/e? and a low read noise of 0.27e? rms using correlated multiple-sampling-based readout circuitry.
关键词： low read noise,high conversion gain,photoelectron counting histogram (PCH),CMOS image sensors (CISs),photon counting
更新于2025-09-16 10:30:52
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Organic Photodetectors and their Application in Large Area and Flexible Image Sensors: The Role of Dark Current
摘要： Organic photodetectors (OPDs) have gained increasing interest as they offer cost-effective fabrication methods using low temperature processes, making them particularly attractive for large area image detectors on lightweight flexible plastic substrates. Moreover, their photophysical and optoelectronic properties can be tuned both at a material and device level. Visible-light OPDs are proposed for use in indirect-conversion X-ray detectors, fingerprint scanners, and intelligent surfaces for gesture recognition. Near-infrared OPDs find applications in biomedical imaging and optical communications. For most applications, minimizing the OPD dark current density (Jd) is crucial to improve important figures of merits such as the signal-to-noise ratio, the linear dynamic range, and the specific detectivity (D*). Here, a quantitative analysis of the intrinsic dark current processes shows that charge injection from the electrodes is the dominant contribution to Jd in OPDs. Jd reduction is typically addressed by fine-tuning the active layer energetics and stratification or by using charge blocking layers. Yet, most experimental Jd values are higher than the calculated intrinsic limit. Possible reasons for this deviation are discussed, including extrinsic defects in the photoactive layer and the presence of trap states. This provides the reader with guidelines to improve the OPD performances in view of imaging applications.
关键词： large area image sensors,charge injection,trap states,dark current,flexible image sensors,organic photodetectors
更新于2025-09-12 10:27:22