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- 摘要
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- 实验方案
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Inserting dome shape microstructure for enhancement of ultraviolet photodetector performance of n-ZnO nanorods/p-Si heterojunction
摘要： A mixed intermediate layer of silica and zinc oxide (SZO) with architecturally dome-shaped microstructure is fabricated and characterized by combining a hydrothermal method and a plasma-enhanced chemical vapor deposition technique. Our results demonstrated that 200 (cid:1)C was an optimum deposition temperature for dome shape architecture SZO layer, acting as an antire?ection layer in the ultraviolet range and buffer layer for growth ZnO nanorods (NRs) arrays. Consequently, at 2.0 V reverse bias, the photo-to-dark current ratio measured with an p-Si/n-ZnONRs photodiode employing the dome-shaped SZO layer is improved by almost three orders of magnitude in the ultraviolet range as compared to that under visible-light illumination.
关键词： ZnO nanorods,Hydrothermal growth,Plasma-enhanced chemical vapor deposition,Photodiodes
更新于2025-09-16 10:30:52
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Pulse Oximetry Using Organic Optoelectronics under Ambient Light
摘要： Light absorption in oxygenated and deoxygenated blood varies appreciably over the visible and near-infrared spectrum. Pulse oximeters use two distinct wavelengths of light to measure oxygen saturation SpO2 of blood. Currently, light-emitting diodes (LEDs) are used in oximeters, which need additional components to drive them and negatively impact the overall size of the sensor. In this work, an ambient light oximeter (ALO) is demonstrated, which can measure photoplethysmography signals and SpO2 using various kinds of ambient light, avoiding the use of LEDs. Spectral filters are combined with organic photodiodes to create the ALO with sensitivity peaks at green (525 nm), red (610 nm), and near-infrared (740 nm) wavelengths. Finally, the wearable ALO is used to measure photoplethysmography signals and SpO2 on the index finger in different indoor and outdoor lighting conditions and the measurements are validated with commercial pulse oximeters under normal and ischemic conditions.
关键词： photoplethysmography,organic photodiodes,oximeters,flexible electronics,wearable sensors
更新于2025-09-16 10:30:52
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Whispering gallery modes enhance the near-infrared photoresponse of hourglass-shaped silicon nanowire photodiodes
摘要： Silicon photodiodes are widely used in applications that require the measurement of the intensity, colour and position of visible light. Silicon is an attractive material for these systems owing to its low cost, low noise, and easy on-chip integration with read-out electronics. However, silicon cannot effectively be used to detect near-infrared (NIR, at wavelengths of 700–1,000 nm) light and short-wave infrared (SWIR, 1,000–1,700 nm) light because of its bandgap of 1.12 eV, which is equivalent to a wavelength of 1,100 nm. Here, we report silicon photodiodes based on hourglass-shaped silicon nanowires that use whispering-gallery-mode resonances to enhance their photoresponse in the NIR–SWIR region of the spectrum. The upper, inverted nanocone of the nanowires increases absorption probability by extending the dwell time of NIR–SWIR photons via the generation of whispering-gallery-mode resonances, whereas the lower nanocone with its low reflectance reabsorbs the light incident from surrounding nanowires. Our devices exhibit a higher responsivity and external quantum efficiency than existing silicon photodiodes at 700–1,100 nm. Furthermore, the responsivity at 1,000 nm is similar to that of commercial InGaAs photodiodes and light at 1,400 nm can also be detected. Using our devices, we demonstrate a heart-rate measurement system that offers performance comparable to commercial setups.
关键词： silicon photodiodes,whispering-gallery-mode resonances,short-wave infrared,near-infrared,hourglass-shaped silicon nanowires
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM) - Hong Kong, China (2019.7.8-2019.7.12)] 2019 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM) - Closed loop controlled optical tracking module for free-space optical communications
摘要： In this paper, a closed loop controlled optical tracking module for free-space optical communication is presented. The motion of the optical tracking module is achieved using a pan-tilt mechanical platform driven by two servomotors. The optical tracking module consists of optical elements including beam splitters and quadrant photodiodes to extract the angular parameters of the incident wave. Optical as well as dynamic modeling is performed to confirm the tracking functionality of the system. Furthermore, to validate the concept, experimentation has been carried out by placing a laser emission module in front of a fixed optical tracking module. The laser was moved in free-space with the help of a mechanical structure and the successful tracking of the optical tracking module has been observed.
关键词： pan-tilt mechanical platform,servomotors,quadrant photodiodes,beam splitters,optical tracking module,free-space optical communication
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - A Compact Circuit Model for Si-Ge Avalanche Photodiodes over a Wide Range of Gain
摘要： A Si-Ge avalanche photodiode circuit model is demonstrated, which includes carrier transit time, avalanche buildup time, and electrical parasitics. Electrical and optical dynamics are accurately captured over a wide range of gain. Excellent matching between simulated and measured 50 Gb/s PAM4 eye diagrams is achieved.
关键词： Avalanche photodiodes (APDs),Optical communication,Modeling
更新于2025-09-12 10:27:22
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Near‐infrared organic photoelectric materials for light‐harvesting systems: Organic photovoltaics and organic photodiodes
摘要： The inherent advantages of organic optoelectronic materials endow light-harvesting systems, including organic photovoltaics (OPVs) and organic photodiodes (OPDs), with multiple advantages, such as low-cost manufacturing, light weight, flexibility, and applicability to large-area fabrication, make them promising competitors with their inorganic counterparts. Among them, near-infrared (NIR) organic optoelectronic materials occupy a special position and have become the subject of extensive research in both academia and industry. The introduction of NIR materials into OPVs extends the absorption spectrum range, thereby enhancing the photon-harvesting ability of the devices, due to which they have been widely used for the construction of semitransparent solar cells with single-junction or tandem architectures. NIR photodiodes have tremendous potential in industrial, military, and scientific applications, such as remote control of smart electronic devices, chemical/biological sensing, environmental monitoring, optical communication, and so forth. These practical and potential applications have stimulated the development of NIR photoelectric materials, which in turn has given impetus to innovation in light-harvesting systems. In this review, we summarize the common molecular design strategies of NIR photoelectric materials and enumerate their applications in OPVs and OPDs.
关键词： organic photodiodes,near infrared,organic optoelectronic materials,organic photovoltaics
更新于2025-09-12 10:27:22
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Response of Waveguide-Integrated Germanium-on-Silicon p-i-n Photodiodes to Neutron Displacement Damage
摘要： The effects of 14-MeV neutron displacement damage (DD) on waveguide-integrated germanium-on-silicon p-i-n photodiodes (PDs) for silicon photonics have been investigated up to fluences of 7.5×1012 n/cm2 (14 MeV), or 1.4×1013 n1-MeVeq /cm2(Si). The study includes measurements of dark current-voltage characteristics across temperature from 150-375 K, measurements of PD junction capacitance, spectral response measurements from 1260 nm to 1360 nm, and frequency response measurements. The devices are found to be susceptible to DD-induced carrier removal effects; however, they also continue to operate without meaningful impact to performance for the DD dose levels examined. Since the PD test chips include silicon photonic integrated grating couplers and waveguides which carry the optical signal to the PD, some assessment of the impact of DD on these passive devices can also be inferred. This work does not examine the short-term annealing or transient behavior of the DD, and instead has only considered the lasting damage that remains after any initial period of room temperature annealing.
关键词： displacement damage,photonics,Radiation effects,neutron radiation,photodiodes,optoelectronic devices
更新于2025-09-12 10:27:22
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Electrical and photoresponse characteristics of 8-(1H-indol-3-ylazo)-naphthalene-2-sulfonic acid/n-Si photodiode
摘要： In this paper, of primary interest is to synthesis 8-(1H-indol-3-ylazo)-naphthalene-2-sulfonic acid (INSA) and to evaluate the main parameters of Au/INSA/n-Si/Al diode in dark and under illumination. Different techniques are used for interpreting the proposed INSA chemical structure. The dark current-voltage measurements were achieved in the temperature range of 293?413 K. It is noticed that INSA films modify the interfacial barrier height of classical Au/n-Si junction. At low applied voltages, the I–V relation shows exponential behavior. The values ideality factor, n, and the barrier height, ?, are improved by heating. The abnormal trend of n and ? is discussed, and a homogenous barrier height of 1.45 eV is evaluated. The series resistance is also calculated using Norde’s function and it changes inversely with temperature. The space charge limited current ruled with exponential trap distribution dominates at relatively high potentials, trap concentration and carriers mobility are extracted. The reverse current of the diode has illumination intensity dependence with a good photosensitivity indicating that the device is promising for photodiode applications.
关键词： Diode parameters,Photodiodes,Conduction mechanism,Azo compounds
更新于2025-09-12 10:27:22
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Photodetector of Shortwave Infrared Range of Format 640 × 512 Elements with Increased Dynamic Range
摘要： The paper substantiates the necessity of expanding the dynamic range in a shortwave infrared (SWIR) photodetector (PD). The traditionally used methods have low efficiency, especially in large-format matrices with a step of not more than 15 μm. The greatest efficiency of expanding the dynamic range (up to 100 dB) is provided by accumulative cells with individually variable transfer characteristic depending on the brightness of the fragments of the observed scene. The paper proposes a simple, in topological implementation, and effective way of expanding the dynamic range based on the auto-tuning of accumulation time individually in each cell of the integrated reading circuit. At the same time, the high steepness and linearity of the transformation in the storage cells with moderate illumination (up to 50–70% of the maximum signal) remains, but the sensitivity in the cells close to saturation decreases. As a result, a linear-log transfer characteristic is formed, providing an extended dynamic range. The paper provides examples of images with an extended dynamic range obtained using the first domestic SWIR camera of format 640 × 512 elements.
关键词： photodiodes,InGaAs,LSI readout,shortwave infrared range,expansion of the dynamic range,photodetectors
更新于2025-09-12 10:27:22
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A High‐Performance Solution‐Processed Organic Photodetector for Near‐Infrared Sensing
摘要： Sensitive detection of near-infrared (NIR) light enables many important applications in both research and industry. Current organic photodetectors suffer from low NIR sensitivity typically due to early absorption cutoff, low responsivity, and/or large dark/noise current under bias. Herein, organic photodetectors based on a novel ultranarrow-bandgap nonfullerene acceptor, CO1-4Cl, are presented, showcasing a remarkable responsivity over 0.5 A W?1 in the NIR spectral region (920–960 nm), which is the highest among organic photodiodes. By effectively delaying the onset of the space charge limited current and suppressing the shunt leakage current, the optimized devices show a large specific detectivity around 1012 Jones for NIR spectral region up to 1010 nm, close to that of a commercial Si photodiode. The presented photodetectors can also be integrated in photoplethysmography for real-time heart-rate monitoring, suggesting its potential for practical applications.
关键词： high responsivity,bulk heterojunctions,photodetectors,organic photodiodes,near-infrared
更新于2025-09-12 10:27:22