- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Regenerable Bead-Based Microfluidic Device with integrated THIN-Film Photodiodes for Real Time Monitoring of DNA Detection
摘要： Nanoporous microbead-based microfluidic systems for biosensing applications allow enhanced sensitivities, while being low cost and amenable for miniaturization. The regeneration of the microfluidic biosensing system results in a further decrease in costs while the integration of on-chip signal transduction enhances portability. Here, we present a regenerable bead-based microfluidic device, with integrated thin-film photodiodes, for real-time monitoring of molecular recognition between a target DNA and complementary DNA (cDNA). High-sensitivity assay cycles could be performed without significant loss of probe DNA density and activity, demonstrating the potential for reusability, portability and reproducibility of the system.
关键词： microfluidics,regenerable biosensor,DNA detection,a-Si:H photodiodes,fluorescence
更新于2025-09-23 15:23:52
-
Design of InP Based High Speed Photodiode for 2 μm Wavelength Application
摘要： In this paper, we proposed and designed the high speed uni-traveling carrier photodiodes operating beyond 2 μm. InGaAs/GaAsSb type-II multiple quantum wells (MQWs) were used as the absorption region of uni-traveling carrier photodiode to have optical response beyond 2 μm. A rate equation model was developed to study the bandwidth characteristics of this photodiode. The carrier dynamics of the carrier sweeping out process was discussed, and the structure parameters of the quantum wells were optimized. Result shows a 3-dB bandwidth over 40 GHz can be achieved with the optimized design. We also studied the feasibility of dual depletion PIN (DD-PIN) photodiode with MQWs absorber. The optimized DD-PIN photodiode could achieve similar bandwidth under relatively high-bias condition.
关键词： high speed photodiodes,type-II quantum well,Carrier dynamic,uni-traveling carrier photodiode
更新于2025-09-23 15:22:29
-
AlGaN Solar-Blind Avalanche Photodiodes with p-Type Hexagonal Boron Nitride
摘要： To improve the performances of AlGaN solar-blind avalanche photodiodes (APD), we propose a separate absorption and multiplication AlGaN APD with a p-hBN layer. The simulated results show that the p-hBN/AlGaN APD significantly decreases the breakdown voltage almost by 23% in comparison with the conventional AlGaN APD due to the use of p-hBN which has a wider bandgap, a higher p-type doping efficiency, and a smaller spontaneous polarization. Moreover, the designed APD keeps an intrinsic solar-blind characteristic even at large reverse bias because the h-BN is completely transparent in the long wavelength direction outside the solar-blind region. The result also confirms that the p-hBN/AlGaN APD has the lower Flicker and impact ionization noise at low and medium frequency under breakdown voltage.
关键词： h-BN,solar-blind,avalanche photodiodes,AlGaN
更新于2025-09-23 15:21:21
-
Investigation of arc dynamics during vacuum arc remelting of a Ti64 alloy using a photodiode based instrumentation
摘要： Understanding the arc dynamics during VAR is important for controlling the final quality of the ingot, as the spatial and temporal distribution of the arc dictates the electric current and energy inputs at the ingot top, which in turn affect the hydrodynamics of the metal in the molten pool and the solidification conditions of the ingot. The arc dynamics during vacuum arc remelting was quantitatively investigated based on the analysis of the light emitted by the arc and reflected by the molten pool using photodiodes placed inside a full-scale furnace. The measurements allowed us to determine the location of the arc luminosity centroid and to follow its displacement as a function of time. They were made during the melt of a Ti64 alloy with an imposed alternated electromagnetic stirring of high intensity. The arc dynamics was found to be most of the time periodic, asymmetrical, and strongly correlated to the evolution of the stirring magnetic field. The arc centroid exhibited three regular displacement patterns throughout the melt. A common characteristic to all three patterns was the relative stability of the centroid during stirring plateaus and its rapid motion during stirring ramps. An evolution towards a much more centered distribution of the centroid was observed with the arc power decrease during the hot-topping phase. Possible implications of the observed arc dynamics on the final quality of the VAR ingot are discussed.
关键词： Electric arc,Photodiodes,Titanium alloy,Vacuum arc remelting,Dynamics
更新于2025-09-23 15:21:21
-
[ACM Press the 24th Annual International Conference - New Delhi, India (2018.10.29-2018.11.02)] Proceedings of the 24th Annual International Conference on Mobile Computing and Networking - MobiCom '18 - Battery-Free Eye Tracker on Glasses
摘要： This paper presents a battery-free wearable eye tracker that tracks both the 2D position and diameter of a pupil based on its light absorption property. With a few near-infrared (NIR) lights and photodiodes around the eye, NIR lights sequentially illuminate the eye from various directions while photodiodes sense spatial patterns of reflected light, which are used to infer pupil’s position and diameter on the fly via a lightweight inference algorithm. The system also exploits characteristics of different eye movement stages and adjusts its sensing and computation accordingly for further energy savings. A prototype is built with off-the-shelf hardware components and integrated into a regular pair of glasses. Experiments with 22 participants show that the system achieves 0.8-mm mean error in tracking pupil position (2.3 mm at the 95th percentile) and 0.3-mm mean error in tracking pupil diameter (0.9 mm at the 95th percentile) at 120-Hz output frame rate, consuming 395μW mean power supplied by two small, thin solar cells on glasses side arms.
关键词： photodiodes,near-infrared,pupil tracking,energy savings,wearable,battery-free,eye tracker
更新于2025-09-23 15:21:21
-
Wearable, Luminescent Oxygen Sensor for Transcutaneous Oxygen Monitoring
摘要： We present a new concept for a wearable oxygen (O2) sensor for transcutaneous O2 pressure (tcpO2) monitoring by combining the technologies of luminescent gas sensing and wearable devices. O2 monitoring has been exhaustively studied given its central role in diagnosing various diseases. The ability to quantify the physiological distribution and real-time dynamics of O2 from subcellular to the macroscopic level is required to fully understand mechanisms associated with both normal physiological and pathological conditions. Despite its profound biological and clinical importance, few effective methods exist for noninvasively quantifying O2 in a physiological setting. The wearable sensor developed here consists of three components: a luminescent sensing film attached onto skin by a carbon tape, an organic light-emitting diode (OLED) as a light source, and an organic photodiode (OPD) as a light detector. All the components are solution-processable and integrated on a plane in a bandage-like configuration. To verify the performance, tcpO2 variations by pressure-induced occlusion were measured in the lower arm and a thumb by the wearable sensor, and the results were comparable to those measured by a commercial instrument. In addition to its flexibility, other features of this sensor render it a potential low-cost solution for the simultaneous monitoring of tcpO2 in any part of a body.
关键词： organic light-emitting diodes,transcutaneous oxygen monitoring,wearable sensors,luminescent oxygen sensing,organic photodiodes
更新于2025-09-23 15:21:21
-
Analysis on different detection mechanisms involved in ZnO-based photodetector and photodiodes
摘要： The present study reports on the comparison between the ultraviolet (UV) light detection mechanisms in ZnO-based photodetectors and ZnO/PEDOT:PSS hybrid photodiodes. Using spray pyrolysis method, ZnO thin films were deposited upon glass substrates. The deposition temperature was varied from 350 to 425 °C and the physical properties of ZnO thin films were investigated. The structural analysis reveals that all the prepared ZnO thin films have a preferred orientation along the (002) plane with hexagonal wurtzite structure. The morphological analysis reveals that the grains are uniformly distributed. Electrical properties reveal that the ZnO thin film deposited at 425 °C shows a higher carrier concentration of 3.76 × 1016 cm?3 with low electrical resistivity value of 2.59 × 102 ? cm. For fabrication of UV photodetectors, the optimum ZnO layer with good electrical and optical property was deposited on ITO substrate with substrate temperature maintained at 425 °C. For the fabrication of hybrid UV photodiodes, poly (3,4 ethylene dioxythiophene):poly (styrene sulphonate) (PEDOT:PSS) and zinc oxide (ZnO) was used as the hole and electron transporting layers, respectively. The current–voltage (I–V) and photoresponse switching characteristics under UV light of the fabricated ZnO-based photodetector and photodiodes were studied and the detection mechanisms of such devices were analysed. It was observed that the ZnO-based photodiodes show higher photoresponsivity (R) value of 0.25 A/W with fast photoresponse switching speed.
关键词： UV light detection,PEDOT:PSS,ZnO,photodetector,spray pyrolysis,photodiodes
更新于2025-09-23 15:21:01
-
Vein detection with near-infrared organic photodetectors for biometric authentication
摘要： We combine a low dark current and high-detectivity near-infrared (NIR)-sensitive organic photodetector with a high-resolution 508 pixels per inch (ppi) oxide thin-film transistor (TFT) backplane to create a large-area thin NIR detector, using processes that are compatible with flat-panel display fabrication. The detector is characterized showing high uniformity and linearity. With the use of a NIR light source, the detector is capable of imaging the (pattern of) veins under the skin in reflection, leading to improved biometric authentication.
关键词： near-infrared organic photodiodes,vein detection,biometric authentication,large-area photodetector arrays
更新于2025-09-23 15:21:01
-
Evaluation of electronic transport and optical response of two-dimensional Fe-doped TiO2 thin films for photodetector applications
摘要： We have carried out the structural, electronic and optical properties of Iron (Fe)-doped TiO2 thin films by sol-gel technique. The results reveal that the thin films form in a granular structure where particle-like grains cover the surface. Photophysical features of the thin films are performed by UV–vis spectrometry. The optical bandgap of undoped TiO2 thin film decreases from 3.17 eV to 3.05 eV with an increase in atomic ratios of Fe content, so the electron transfer is easier from the valence band to the conduction band. The current-voltage (I–V) and capacitance-voltage (C–V) characteristics of the undoped and Fe-doped TiO2 thin films are investigated under dark and various lighting intensities. Our results show that the photocurrents increase with increasing intensities of illumination. The photodiodes also show a decreasing capacitance with increasing frequency. From I–V and C–V plots, the photodiodes show rectifying properties and good photovoltaic behavior. Herein, the results display that the produced new Fe-doped TiO2 thin film samples can be used for photodetector applications.
关键词： Fe-doped TiO2,I-V,Photodiodes,Bandgap
更新于2025-09-23 15:21:01
-
Structural and optoelectronic characterization of Cu2CoSnS4 quaternary functional photodetectors
摘要： Al/p-Si/Cu2CoSnS4/Al quaternary functional semiconductor photodetectors showing solar detector properties were produced via sol-gel method. SEM, EDS and XRD techniques were used in the confirmation of the chemical composition of the photodiodes where nanoparticle like characteristics of Cu2CoSnS4 was seen. UV-vis spectroscopy was used in the investigation of optoelectronic characteristics. It was seen that photodiodes have a high absorption rate with minimum reflectance, bandgap energy was calculated as 1.19 eV. Current – time and current – voltage characteristics of the photodiodes revealed that photodiodes are sensitive to daylight; photodiodes present rectifying characteristics. Thermionic emission theory was used in the calculation of barrier height, ideality factor, photoresponse, photosensitivity, and linear dynamic rate characteristics. Capacitance – voltage, conductance – voltage, corrective capacitance – voltage, corrective conductance – voltage graphs were used to investigate the electrical properties of the Al/p-Si/Cu2CoSnS4/Al photodiodes. The electrical characteristics of the photodiodes reflect frequency dependent characteristics. Such a behaviour was found to be an indication of the existence of interface states. The density of interface (Dit) calculations revealed that the density of interface states strongly depends on AC signal frequency where diminished Dit was seen for increased signal frequency.
关键词： photodetector,photoresponse,Cu2NiSnS4 photodiodes,quaternary functional photodiodes,solar detectors
更新于2025-09-23 15:19:57