- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Integrated microsensor for precise, real-time measurement of junction temperature of surface-mounted light-emitting diode
摘要： Light-emitting diodes (LEDs) are widely used in many industrial applications owing to their high performance and efficiency compared with conventional lighting systems. However, a considerable amount of input power is inevitably dissipated into heat at the LED junction, which can degrade the performance and reliability of the LED; thus, it is important to monitor the change in the junction temperature of the LED. In this study, we present a micro-temperature sensor-integrated surface-mounted device (SMD) for accurate and real-time measurement of the junction temperature of an LED. The LED is mounted on a microfabricated Pt sensor in a similar way to the typical SMD assembly. The heat generated at the LED junction is conductively transferred to the microsensor, increasing the temperature and changing its electrical resistance. In contrast to the conventional techniques for thermal characterization of LEDs, the integrated microsensor provides real-time information on the junction temperature with high precision, reproducibility, and simplicity. Additionally, the temperature of the solder, which is not easily accessible but is closely related to the reliability of the LED, can be estimated by analyzing the thermal resistance of the LED package. Experimental and numerical results indicate a linear correlation (R2 = 0.988) between the junction and sensor temperatures, which is practically useful for the thermal management of the miniaturized SMD-LED.
关键词： Junction temperature,Light-emitting diode,Thermal transient test,Microsensor,Surface-mounted device,Thermal management
更新于2025-09-12 10:27:22
-
Back-to-back Schottky junction photodetectors based on CVD grown CsPbBr <sub/>3</sub> microcrystalline striped films
摘要： In recent years, a new type of lead halide perovskite has attracted a lot of attention for next-generation photodetectors (PDs) with high responsivity, good detectivity, and fast photoresponse speed. Specifically, cesium based all-organic perovskites exhibit better photostability and therefore have achieved increasing success in PDs recently. For reducing the leak current and increasing the response speed of photo-conductive PDs, back-to-back Schottky junction PD is designed and fabricated through a direct growth approach of CsPbBr3 microcrystal (MC) films on indium tin oxide (ITO) electrodes by the chemical vapor deposition (CVD) method. Due to the enhanced Schottky barrier height and threshold voltage between CsPbBr3 and ITO electrodes, the PD exhibits the on/off ratio of up to 104, peak responsivity of 3.9 AW?1, detectivity of 3.8 × 1012, and fast response speed of 0.22 ms (rise time) and 0.45 ms (decay time). In addition, the stability of PD is also enhanced by the high crystal quality of CVD grown CsPbBr3 MCs.
关键词： microcrystalline films,Schottky junction,photodetectors,CsPbBr3,chemical vapor deposition
更新于2025-09-12 10:27:22
-
High-Concentration, Low-Temperature, and Low-Cost Excimer Laser Doping for 4H-SiC Power Device Fabrication
摘要： We developed a novel KrF excimer laser doping system for 4H-SiC power devices, and demonstrated laser doping of SiC with Al thin film deposited on the surface. As seen from the results of the Al depth profile, high concentration implantation (~ 1021 cm-3 at the surface) of Al was achieved by laser ablation of the Al thin film. A high, built-in-potential (~3.5 V) of the pn junction diode was clearly seen in the I-V curve. In addition, the contact resistivity of the deposited Al/Ti electrodes on the surface was 1.9 × 10?4 Ωcm2 by TLM (Transmission Line Model). It was confirmed that a high concentration of Al doping and low contact resistivity were achieved by the KrF excimer laser doping system.
关键词： excimer laser doping,4H-SiC,Al thin film,pn junction diode
更新于2025-09-12 10:27:22
-
Light intensity and spectral dependence characteristics of silicon nanowire/PEDOT:PSS heterojunctions solar cells
摘要： Recently, research on Si/conducting organic polymer heterojunction solar cells has gained prominence owing to their low fabrication cost and potential for reasonably good efficiency. Poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) coated over n-type Si forms such heterojunction which has theoretical capabilities comparable to the conventional p-n Si junction. However these devices still need fabrication parameters optimization in order to compete with conventional p-n junction silicon solar cells. Here, we report the photoresponse of Ag/PEDOT:PSS/n-SiNW/Al solar cell at different light intensities and different wavelengths. The device is fabricated by spin coating the PEDOT:PSS over n-Si NW based Si substrates. It is further noted that the short circuit current is significantly lower in J-V response than that derived from external quantum efficiency measurements. It is observed that the photocurrent density and fill factor deteriorates significantly at higher intensities. This is suggestive of some space charge build up at Si-PEDOT:PSS interface at higher intensities because of difference in hole mobility in Si and PEDOT:PSS. This could also be strongly attributed to structural changes in the PEDOT:PSS layer which might change the charge carrier dynamics and hence the electrical response of the layer. The response of cell with varying intensity can help to optimize the illumination condition for the cell. The wavelength response of the cell can help us better understand the solar cell working and can help in optimizing the fabrication parameters. This opens up new area of intensive research required in order to optimize polymer layer properties and improving the performance of PEDOT:PSS/SiNW-based solar cell.
关键词： PEDOT:PSS,Hetero-junction solar cells,Silicon nanowires,Light trapping
更新于2025-09-12 10:27:22
-
[IEEE 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - St. Petersburg, Russia (2019.10.17-2019.10.18)] 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - The Multi-Criteria Optimization in the LTspice Simulation Software of a JFet class AB Buffer Amplifier for Operation at Low Temperatures
摘要： A high-speed buffer amplifier (BA) for analog microcircuits field-effect transistors is proposed. The scheme differs from the known circuit solutions by a small number of elements and can operate within the range of cryogenic temperatures. In the LTSpice simulation software, the optimal control parameters were selected using the DEAP (Distributed Evolutionary Algorithm in Python) library of distributed evolutionary calculations and the NSGA-II multi-criteria optimization algorithm. Minimization of offset voltage, static current consumption and dead band width on the amplitude characteristic at low temperatures were chosen as the priority parameters of the control unit.
关键词： low-temperature electronics,class AB operation,optimization of analog electronic circuit,operational amplifier,LTspice environment,buffer amplifier,junction field-effect transistors
更新于2025-09-12 10:27:22
-
[IEEE 2019 International Conference on Power Generation Systems and Renewable Energy Technologies (PGSRET) - Istanbul, Turkey (2019.8.26-2019.8.27)] 2019 International Conference on Power Generation Systems and Renewable Energy Technologies (PGSRET) - Performance Comparison of (GaAS/GaAs) and (InGaP/GaAs) Tunnel Junction in Multi-Junction Solar Cells
摘要： This study presents a comparison of the performance of two multi-junction solar cells in terms of simulated short-circuit current density, open circuit voltage, efficiency and fill factor one of these cells with an InGaP / GaAs structure with a GaAs / GaAs junction tunnel and the other with the same structure but with an InGaP / GaAs hetrojunction tunnel. The silvaco-ticad software has been used to analyze and study these performances for both solar cells, the total thickness is specified to 0.66μm of top solar cell (GaInP), and the thickness of bottom solar cell (GaAs) is 2.64 μm and the tunnel junction with thickness 0.040 μm. He result of the simulation exposures for these multiple junction solar cells gives a conversion efficiency maximum of 24.2343% (AM1.5) would be obtained by choosing the p-In0.5Ga0.5P/n-GaAs tunnel heterojunction.
关键词： silvaco-ticad,tunnel junction,conversion efficiency,InGaP/GaAs,multi-junction solar cell
更新于2025-09-11 14:15:04
-
[IEEE 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Sydney, Australia (2018.11.10-2018.11.17)] 2018 IEEE Nuclear Science Symposium and Medical Imaging Conference Proceedings (NSS/MIC) - Laser Doped Layer in CdTe Diode Detectors Revealed by Synchrotron XPS
摘要： The X-ray photoelectron spectroscopy (XPS) with 650 eV synchrotron radiation was applied to study the modified surface in the CdTe diode-type X/γ-ray detectors fabricated by the laser-induced doping techniques. Semi-insulating (111)-oriented p-like CdTe single crystals, pre-coated with an In dopant film, were irradiated by nanosecond pulses of a YAG:Nd laser (λ = 1064 nm). The activation of the In/CdTe interface and doping were carried out by laser irradiation of the metalized samples from the In side or through the semiconductor which was transparent for such wavelength. In the first case, laser-induced doping was attributed to the generation of laser-stimulated stress and shock waves which incorporated In atoms into the CdTe surface region. In the second case, it was possible to directly affect the In/CdTe interface because laser radiation was strongly absorbed by a thin layer of the deposited In dopant film and the CdTe was dissolved in molten In. The distribution of In and Cd atoms with the depth and atomic bonding in the In/CdTe interface were analyzed based on the high resolution In 3d and Cd 3d peaks in the XPS spectra of the formed In/CdTe diode structures subjected to Ar-ion sputtering. The stoichiometry and transformation of electronic structure in the modified CdTe layer were analyzed. Rectification properties of the created In/CdTe/Au diodes were due to the formation of an In enriched submicron layer as result of laser-induced solid-phase or liquid-phase doping that depended on irradiation of the In/CdTe structure from the metalized or semiconductor side, respectively. The created In/CdTe/Au diodes have been promising for X/γ-ray detector application.
关键词： laser doping,XPS spectra,synchrotron radiation,CdTe crystals,p-n junction
更新于2025-09-11 14:15:04
-
Filterless Polarization‐Sensitive 2D Perovskite Narrowband Photodetectors
摘要： An important factor for the high performance of light-harvesting devices is the presence of surface trappings. Therefore, understanding and controlling the carrier recombination of the organic?inorganic hybrid perovskite surface is critical for the device design and optimization. Here, we report the use of aluminum zinc oxide (AZO) as the anode to construct a p?n junction structure MAPbBr3 nuclear radiation detector. The AZO/MAPbBr3/Au detector can tolerate an electrical field of 500 V·cm?1 and exhibit a very low leakage current of ～9 nA, which is 1 order of magnitude lower than that of the standard ohmic contact device. The interface state density of AZO/MAPbBr3 contact was reduced from 2.17 × 1010 to 8.7 × 108 cm?2 by annealing at 100 °C under an Ar atmosphere. Consequently, a photocurrent to dark current ratio of 190 was realized when exposed to a green light-emitting diode with a wavelength of 520 nm (～200 mW·cm?2). Simultaneously, a high X-ray sensitivity of ～529 μC·Gyair?1 cm?2 was achieved under 80 kVp X-ray at an electric field of 50 V·cm?1. These results demonstrate the use of surface engineering to further optimize the performance of MAPbBr3 detectors, which have many potential applications in medical and security detection with low radiation dose brought to the human body.
关键词： p?n junction,X-ray detector,interface state density,MAPbBr3 PSC,annealing
更新于2025-09-11 14:15:04
-
Interface Defect Engineering for Improved Graphene-Oxide-Semiconductor Junction Photodetectors
摘要： The deeply depleted graphene-oxide-semiconductor (D2GOS) junction detector provides an effective architecture for photodetection enabling direct readout of photogenerated charge. Due to an inherent gain mechanism proportional to graphene’s high mobility (μ), this detector architecture exhibits large responsivities and signal-to-noise ratios (SNR). The ultimate sensitivity of the D2GOS junction detector may be limited, however, due to the generation of dark charge originating from interface states at the semiconductor/dielectric junction. Here, we examine the performance limitations caused by dark charge and demonstrate its mitigation via the creation of low interface defect junctions enabled by surface passivation. The resulting devices exhibit responsivities exceeding 10,000 A/W—a value which is 10x greater than that of analogous devices without the passivating thermal oxide. With cooling of the detector, the responsivity further increases to over 25,000 A/W, underscoring the impact of surface generation on performance and thus the necessity of minimizing interfacial defects for this class of photodetector.
关键词： 2D Materials,Photodetector,Interface Defects,GOS Junction,2D Detector,Graphene,High Responsivity
更新于2025-09-11 14:15:04
-
Physics of Energy Conversion () || 10. Photovoltaic energy conversion
摘要： In a photovoltaic device, solar energy is converted into electricity along a path very different from the one taken in a solarthermal power plant. Here, in a first step the energy of the solar photons is converted into chemical energy in a solid state absorber. This means that the absorber is brought into an electronically excited state involving a reconfiguration of its charge carriers by the generation of electron/hole (e?/h+)-pairs, i.e. by the following reaction: Ground state + ?? → e? + h+. Here, ?? represents a photon with sufficient energy to bring an electron to the excited state. The chemical energy of the charge carrier ensembles in the conduction and valence bands is then converted into electrical energy by spatially separating the e?/h+-pairs via electrical contacts of the absorber which are electron or hole selective, respectively. In general such selective contacts can only be realized by a jump in the material properties between the two contacts, an example for this being a pn-junction. Since under illumination electrons and holes have different electrochemical potentials in the absorber material, this separation leads to a voltage drop between the contacts selective for the different charge carrier types. It is thus the selectivity of the contacts that introduces the built-in asymmetry into the solar cell, making it a usable voltage source (see Section 5.2). This basic working principle is true for all types of solar cells, ranging from conventional solar cells built from crystalline silicon (c-Si) over thin film solar cells fabricated from different materials such as, e.g. Cu(In,Ga)Se2 (CIGS) to organic or dye sensitized solar cells, and is schematically shown in Figure 10.1.
关键词： electricity,solid state absorber,solar energy,photovoltaic,pn-junction,dye sensitized solar cells,organic solar cells,CIGS,thin film solar cells,crystalline silicon,electron/hole pairs
更新于2025-09-11 14:15:04