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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Why and how does car-roof PV create 50 GW/year of new installations? Also, why is a static CPV suitable to this application?
摘要： With this car-roof PV, 70 % of passenger’s may be able to run by solar energy. The potential of the market size is 50 GW/year. However, it is not an easy task to meet the requirement of the main component of EV and the creation of the massive market. It is also apparent that the market will be small as far as we only try to apply the conventional crystalline Si cells. The CPV technology with high power conversion efficiency and capable of coloring and covering on the three-dimensional curved surface is suitable for this market. The static CPV is useful for this application with a better collection of diffused sunlight. One of the problems is the spectrum mismatching. However, this issue is easily solved by adjustment of the bandgap of the bottom cell.
关键词： car-roof PV,multi-junction cells,solar energy,electric vehicles,static CPV
更新于2025-09-23 15:19:57
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Effects of post bonding annealing on GaAs//Si bonding interfaces and its application for sacrificial-layer-etching based multijunction solar cells
摘要： By using the sacrificial layer (SL) etching, GaAs substrates are separated from III–V epi substrate//Si substrate junctions that are made by surface activated bonding (SAB) technologies. The post-bonding low-temperature (300-?C) annealing plays an essential role in achieving a promising (～90%) bonding yield. The effects of the post-bonding annealing are investigated by hard X-ray photoemission spectroscopy and current–voltage measurements of GaAs//Si bonding interfaces. It is found that the concentration of oxygen atoms at interfaces is reduced and the resistance decreases to 1.6–2.1 m??cm2 by the low-temperature annealing. Aluminum fluoride complexes are not observed by X-ray photoelectron spectroscopy on the exposed surfaces of separated GaAs substrates. The roughness average of the surfaces is ≈0.25–0.30 nm. The characteristics of double junction cells fabricated on the GaAs//Si junctions prepared by the SL etching are almost the same as those of cells fabricated by dissolving GaAs substrates after bonding. These results indicate that multijunction cells could be fabricated in a process sequence compatible with reuse of GaAs substrates by combining the SL etching and SAB.
关键词： Sacrificial layer etching,GaAs//Si double junction cells,Surface activated bonding,Low temperature annealing,Epitaxial lift-off
更新于2025-09-23 15:19:57
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[IEEE 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - HangZhou, China (2018.9.5-2018.9.7)] 2018 11th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT) - Input coupling systems for terahertz gyro-TWAs
摘要： Input coupling systems for THz gyrotron traveling wave amplifiers (gyro-TWAs) are presented in this paper. These form one of the most critical parts of the gyro-TWA as it feeds the low power seed signal into the interaction circuit and incorrect design can lead to cessation of the amplification. The T-junction, multihole and multiarm coupler types were simulated in CST Microwave Studio and their optimized reflection and transmission characteristics, operating at a central frequency of 0.37 THz are presented. A scaled multiarm coupler, designed to then operate at 94 GHz, was manufactured and its microwave properties measured on a vector network analyser.
关键词： CST Microwave Studio,multihole coupler,THz gyro-TWAs,T-junction,multiarm coupler,input coupling systems
更新于2025-09-23 15:19:57
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Fully Metallic Anisotropic Lens Crossover-in-Antenna Based on Parallel Plate Waveguide Loaded With Uniform Posts
摘要： This paper describes a compact high-performance orthomode transducer (OMT) with a circular waveguide input and two rectangular waveguide outputs based on the superimposition of three aluminum blocks. Several prototypes operating in the band 1 (31–45 GHz) of the atacama large millimeter array have been fabricated and measured. The design is based on the use of a turnstile junction that is machined in a single block, requiring neither alignment nor a high degree of mechanical tolerances. Thus, a high repeatability of the design is possible for mass production. Across the 31–45 GHz band, the isolation is better than 50 dB and the return losses at the input and outputs of the OMT are better than ?25 dB.
关键词： turnstile junction,orthomode transducer (OMT),polarization diplexer,Radio astronomy
更新于2025-09-23 15:19:57
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Analysis of a single-mode waveguide at sub-terahertz frequencies as a communication channel
摘要： We study experimentally the transmission of an electromagnetic waveguide in the frequency range from 160 to 300 GHz. Photo-mixing is used to excite and detect the fundamental TE10 mode in a rectangular waveguide with two orders-of-magnitude lower impedance. The large impedance mismatch leads to a strong frequency dependence of the transmission, which we measure with a high-dynamic range of up to 80 dB and with high frequency-resolution. The modified transmission function is directly related to the information rate of the waveguide, which we estimate to be about 1 bit per photon. We suggest that the results are applicable to a Josephson junction employed as a single-photon source and coupled to a superconducting waveguide to achieve a simple on-demand narrow-bandwidth free-space number-state quantum channel.
关键词： communication channel,TE10 mode,sub-terahertz frequencies,Josephson junction,impedance mismatch,superconducting waveguide,single-photon source,waveguide
更新于2025-09-23 15:19:57
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[IEEE 2019 International Conference on Electrotechnical Complexes and Systems (ICOECS) - Ufa, Russia (2019.10.21-2019.10.25)] 2019 International Conference on Electrotechnical Complexes and Systems (ICOECS) - Energy efficiency improvement of OFDM-based Radio-over-fiber systems enabled with PAPR decrease method
摘要： The roadmap evolution and historical milestones of electromagnetic energy conversion techniques and related breakthroughs over the years are reviewed and presented with particular emphasis on low-density energy-harvest technologies. Electromagnetic sources responsible for the presence of ambient radio-frequency (RF) energy are examined and discussed. The effective use and recycling of such an ambient electromagnetic energy are the most relevant and critical issue for the current and future practicability of wireless energy-harvesting devices and systems. In this paper, a set of performance criteria and development considerations, required to meet the need of applications of ambient electromagnetic energy harvesting, are also derived from the radiating source analysis. The criteria can be calculated from a simple measurement of the I–V nonlinear behavior of RF rectification devices such as diodes and transistors, as well as linear frequency behavior (S-parameters). The existing rectifying devices are then reviewed in light of the defined performance criteria. Finally, a technological outlook of the performances that can be expected from different device technologies is assessed and discussed. Since the proposed spindiode technology would present the most promising device platform in the development of the most useful ambient energy harvesters, a special highlight of this disruptive scheme is provided in the presentation of this work.
关键词： diodes,metal–insulator–metal (MIM),spindiode,magnetic tunnel junction (MTJ),energy harvesting,Schottky diode,crystal rectifier,Ambient radio-frequency (RF) energy,backward diode
更新于2025-09-23 15:19:57
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Exper?±mental and Numer?±cal Analysis of the Effect of Components on a Double-Sided PCB on LED Junction Temperature and Light Output Using CFD
摘要： In today’s lighting industry, with developing technology and a widened usage area, LEDs have become very popular due to their higher energy efficiency and longer life. In the present study, the effect of electronic components on printed circuits and the radiation level on light output was studied. The performed analysis was validated with an experimental method. For the finite volume method, FloEFD 2019, commercial software, was used. The ambient temperature was assumed to be 23 °C. The value of solar irradiance was taken as 1009 W/cm2. LEDs on a PCB were driven at 70 mA at first and then at 50 mA, and, by exerting power on all electronic components, analyses were performed. Both sides of the PCB were examined, and, in order to achieve efficient heat conduction, the power and distribution of the electronic components on the back side of the LEDs were optimized. With a new electronic circuit design, analyses were performed at 50, 55, 60, 65, and 70 mA. It was determined that the highest light output was achieved at 65 mA and that the distribution of electronic components on a PCB indirectly affects light output through junction temperature (T j).
关键词： Laminar natural convection,Junction temperature,Monte Carlo radiation,LED automotive lamp,Computational fluid dynamics (CFD)
更新于2025-09-23 15:19:57
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The transparent device of CdS quantum dots modified Cu2O/ZnO orderly nano array p-n junction towards the enhanced photovoltaic conversion
摘要： The transparent device of CdS QDs modified Cu2O/ZnO nano array p-n junction is prepared via simple continuous magnetron sputtering method and chemical deposition. The p-n junction device with good stability exhibits decent transparency of about ~80% in visible light, and evident photovoltaic response enhancement of about ~100 times than the unmodified sample, that can be mainly attributed to the CdS QDs with high QY can improve the visible light response, the p-n junction with self-photovoltage and the ZnO order arrays can improve the transport of the photon-generated carriers.
关键词： p-n junction,CdS quantum dots,Orderly nano array,Transparent device
更新于2025-09-23 15:19:57
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Effect of tunnel junction grown at different growth rates on the optical properties and improved efficiency of InGaP/GaAs double-junction solar cells
摘要： The optical properties of InGaP/GaAs double-junction solar cells (DJSCs) grown by metalorganic chemical vapor deposition were investigated using temperature- and excitation power-dependent photoluminescence (PL) measurements. The InGaP/GaAs DJSC samples studied were the same structures; however, the corresponding tunnel junctions were grown at different growth rates (1.0 and 1.5 ?/s). The PL spectrum measured at 10 K for both samples exhibited a strong main peak at ~1.97 eV with a weak shoulder peak at ~1.94 eV, which could be attributed to the emissions of disordered and ordered InGaP, respectively. A PL peak located at ~1.91 eV was observed under a low excitation power, originating from the donoreacceptor pair (DAP) transition. With the increase in the temperature, the emission related to the DAP of the sample grown at a growth rate of 1.0 ?/s was found to be less dominant compared with the sample grown at a growth rate of 1.5 ?/s. The power-conversion ef?ciency of the sample grown at a growth rate of 1.0 ?/s was improved compared to that of the sample grown at a growth rate of 1.5 ?/s, owing to fewer defect states. Our results help understand the luminescence properties of InGaP/GaAs DJSCs, which could be a crucial factor in fabricating high-ef?ciency solar cells.
关键词： InGaP/GaAs,Growth rate,Photoluminescence,Double-junction solar cell
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