- 标题
- 摘要
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- 实验方案
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Direct Imaging of Current‐Induced Transformation of a Perovskite/Electrode Interface
摘要： Formamidinium-lead-iodide (FAPbI3) perovskite films are subjected to a long-term action of the constant electrical current in the dark, using planar vacuum-deposited gold electrodes. The current-induced transformation is monitored by the time-of-flight secondary ion mass spectrometry (ToF-SIMS) mapping complemented by microscopic, spectroscopic methods, and X-ray diffraction. The migration of chemical species inside the lateral interelectrode gap is clearly visualized by ToF-SIMS. Those species correspond to both electrode material and perovskite itself, so that the perovskite/electrode interface becomes disrupted. As a result, the interelectrode gap shrinks, which is reflected in the surface images.
关键词： interfaces,dark current,gold electrodes,perovskites,ToF-SIMS mapping
更新于2025-11-25 10:30:42
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Dark current in long-wave cascade-transport infrared up-converters
摘要： Reducing the dark current in an infrared (IR) photodetector is one of the most important aspects in improving the detector’s performance. This article attempts to clarify the dominant paths of dark current and reduce it in a long-wave cascade-transport IR up-converter (CIUP), which has been reported to be a potential candidate for very-large-scale IR detection/imaging. The four paths of the dark current are considered, including the ground state sequential tunneling, thermionic emission onto the continuum, thermally-assisted transition onto the excited state of the absorption quantum well (QW) or some energy levels in the transport region. Accordingly three designs of the band structure are proposed for long-wave CIUPs, with miniband-to-miniband intersubband transition, bound-to-miniband transition and step-bound-to-miniband transition. Samples based on these designs are fabricated and measured. Both the calculated electron concentration distributions and the measured dark currents show that the step-bound-to-miniband structure is the most effective in cutting down the dark current, in which the superlattice barrier and InGaAs absorption QWs help to reduce dark current related to tunneling, thermionic emission and thermally-assisted tunneling.
关键词： Dark current,Up-converter,Step-bound-to-miniband,Long-wave infrared,Cascade
更新于2025-09-23 15:23:52
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43- and 50-Mp High-Performance Interline CCD Image Sensors
摘要： This paper describes the design and performance of two new high-resolution interline charge-coupled device image sensors for use in industrial, machine vision, and aerial photography applications. These sensors feature 4.5-μm pixels, 4 outputs, fast dump gate, horizontal lateral overflow drain, and vertical electronic shutter. The 43-Mp sensor has a 35-mm optical format and the 50-Mp sensor has a larger format with a 2.175:1 aspect ratio that matches many modern mobile phone displays. This paper discusses the challenges and solutions to manufacture such large sensors with superior image quality such as uniformity, read noise, dark current, smear, transfer gate blooming, lag, and so on.
关键词： dark current,lithography stitching,interline transfer (IT),stepper,multiple outputs,image sensor,large format,charge-coupled device (CCD),smear,Blooming
更新于2025-09-23 15:22:29
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AlInSb/InSb Heterostructures for IR Photodetectors Grown by Molecular-Beam Epitaxy
摘要： A photodetector heterostructure based on AlInSb/InSb was grown by molecular-beam epitaxy. Mesostructures of different diameters were fabricated. The temperature dependence of the dark current was measured. It was demonstrated that the built-in barrier blocks the flow of majority charge carriers, thus reducing the dark-current density (relative to that for a pin structure based on InSb). The measured dependence of the dark current on the mesostructure size revealed that the bulk current component prevails over the surface one.
关键词： nBn detector,molecular-beam epitaxy,dark current,InSb,IR photodetector
更新于2025-09-23 15:21:01
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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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Surface modification of AlN using organic molecular layer for improved deep UV photodetector performance
摘要： Direct wide bandgap of 6.2 eV, high temperature robustness and radiation hardness make aluminum nitride (AlN) a preferable semiconductor for deep ultraviolet (UV) photodetection. However, the performance and reliability of AlN- based devices is adversely affected by a large density of surface states present in AlN. In this work, we have investigated the potential of a monolayer of organic molecules in passivating the surface states of AlN which improved the performance of AlN- based metal- semiconductor- metal (MSM) deep UV photodetectors. The organic molecules of Meso-5,10,15-triphenyl-20-(p-hydroxyphenyl)porphyrin Zn(II) complex (ZnTPP(OH)) were successfully adsorbed on AlN surface, forming a self- assembled monolayer (SAM). The molecular layer was characterized by contact angle measurement, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The surface modification of AlN effectively reduced dark current of the photodetector by ten times without degrading the magnitude of photo current, especially at low voltages. Photo to dark current ratio (PDCR) was enhanced from 930 to 7835 at -2V and the responsivity doubled from 0.3 mA/W to 0.6 mA/W at 5V. Moreover, the rise and fall times of the detector were found to decrease after the surface modification process. Our results suggest that SAM of porphyrin molecules effectively passivated the surface states in AlN which resulted in improved photodetector performance.
关键词： Dark current,PDCR,MSM UV photodetector,Surface states,SAM,Responsivity,Temporal response
更新于2025-09-23 15:19:57
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A comparison of mechanisms for improving dark current characteristics in barrier infrared photodetectors
摘要： The dark current characteristics in InAs/GaSb type-II superlattice (SL) barrier infrared photodetectors are theoretically investigated using the drift-diffusion-based device simulator. It is shown that both structures can effectively reduce the dark current compared to the p-i-n photodiode without barrier, and the dependence on the barrier doping density are discussed in detail. There exists an optimum doping density to minimize the dark current in active region (n type), for which two different engineered structures, i.e., called pBn and nBn, are evaluated.
关键词： dark current,pBn,InAs/GaSb type-II superlattice,barrier infrared photodetectors,nBn
更新于2025-09-23 15:19:57
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Dark-current reduction accompanied photocurrent enhancement in p-type MnO quantum-dot decorated n-type 2D-MoS <sub/>2</sub> -based photodetector
摘要： A highly crystalline single- or few-layered 2D-MoS2 induces a high dark current, due to which an extremely small photocurrent generated by a few photons can be veiled or distorted. In this report, we show that suppression in the dark current with the enhancement in the photocurrent of a 2D-based photodetector, which is a prerequisite for photoresponse enhancement, can be achieved by constructing an ideal p-n junction based on functionalizing n-type 2D-MoS2 with p-type quantum dots (QDs). Highly crystalline solution-processed manganese oxide QDs (MnO QDs) are synthesized via the pulsed femtosecond laser ablation technique in ethanol. The ablated MnO QDs are spray-coated on an exfoliated 2D-MoS2 substrate with interdigitated Au electrodes through N2-assisted spraying. In the resulting MnO QD-decorated 2D-MoS2 photodetector with a heterojunction, dark current is reduced and is accompanied by photocurrent enhancement, thereby markedly improving the photoresponsivity and detectivity of MoS2-based devices. To elucidate the underlying mechanisms contributing to this enhancement, power- and wavelength-dependent photoresponses, along with material characterizations based on spectroscopic, chemical, morphological measurements, and analyses, are discussed.
关键词： dark current,quantum dots,2D-MoS2,p-n junction,photodetector,photocurrent
更新于2025-09-23 15:19:57
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Reducing the Dark Current of Cuprous Oxide/Au Schottky Photodetector for High Signal-to-noise Ratio Imaging
摘要： Photodetectors (PDs) as image sensors have been widely used in imaging system due to their outstanding photosensitivity. The improvement of imaging quality (signal-to-noise ratio, SNR) can be realized by reducing the dark current of PDs. Conventionally, interfacial engineering can effectively suppress the dark current of PDs. Nevertheless, these techniques are hard to be applied in practical imaging systems owing to their complicated process. In this work, we proposed a facile method to reduce the dark current of Cu2O/Au Schottky PDs, and further demonstrated its application in high SNR imaging system. By applying a small external bias of -120 μV, the dark current of PDs decreases from 27 nA to 0.6 nA, with 4023% improvements of ON/OFF ratio. Additonaly, a model based on free carriers generated by rich trap-state and thermal excitation under asymmetric internal electric field was proposed to understand this phenomenon. Finally, a high-resolution image with high SNR (48 dB) was acquired, which is close to that of commercial Si-CDD and CMOS. Our results provide a convenient way to reduce the dark current and improve the image quality, also suggest Cu2O is potentially an attractive candidate to be applied in optical imaging applications.
关键词： SNR,dark current,photodetectors,imaging,Cu2O/Au Schottky
更新于2025-09-23 15:19:57
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Low Dark Current 1.55 Micrometer InAs Quantum Dash Waveguide Photodiodes
摘要： Photodiodes and integrated optical receivers operating at 1.55 micrometer (μm) wavelength are crucial for long-haul communication and data transfer systems. In this paper, we report C-band InAs quantum dash (Qdash) waveguide photodiodes (PDs) with a record-low dark current of 5 pA, a responsivity of 0.26 A/W at 1.55 μm, and open eye diagrams up to 10 Gb/s. These Qdash-based PDs leverage the same epitaxial layers and processing steps as Qdash lasers and can thus be integrated with laser sources for power monitors or amplifiers for pre-amplified receivers, manifesting themselves as a promising alternative to their InGaAs and Ge counterparts in low-power optical communication links.
关键词： C-band communication,photodiodes,optoelectronics,low dark-current,quantum dashes
更新于2025-09-23 15:19:57