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- 2019
- polycrystalline ferrite-garnet
- magnetoplasmonic crystals
- magnetooptical effects
- deposition
- ion-beam methods
- sputtering
- plasmon resonance
- Physics
- Moscow Technological University
- Moscow State University
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Performance of polycrystalline GaN based metal-semiconductor-metal (MSM) photodetector with different contact
摘要： This paper describes performance of polycrystalline GaN based metal-semiconductor-metal (MSM) photodetector using different contact; Al, ITO, Ni and Pt. The performance of each photodetector was investigated in term of electrical resistivity (r ), signal-to-noise ratio (SNR), responsivity (R), internal quantum efficiency (η) and temporal responsivity. From the results, Ni is suggested to be a good contact for the photodetector. This is due to diffusion of NixO, formed by residual oxides on the GaN layer, into the Ni contact reduced the resistivity, thereby increasing the electrical conductivity of the photodetector. The photodetector with Ni contact demonstrated significant increase in SNR behavior with increasing bias voltage, while its r value was measured to be 2.02 M?.cm2, and η was 3.13%, 2.36% and 1.52%, at λ = 342 nm, 385 nm and 416 nm, respectively. From the temporal responsivity measurement, the rise time = 1.75 sec, the recovery time = 1.87 sec and the sensitivity = 5840%.
关键词： MSM photodetector,electrical contact,resistivity,internal quantum efficiency and temporal responsivity,signal-to-noise ratio,polycrystalline GaN,responsivity
更新于2025-09-12 10:27:22
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Preparation of novel lead-free Ag-doped glass frit for polycrystalline silicon solar cells by sol-gel method
摘要： A novel Ag-doped glass frit is prepared by the sol-gel method. Nitrogen adsorption-desorption isotherms indicate that the frit has a large BET surface area and a small particle size which promotes front contact metallization. When the glass frit is used for the front contact electrode of polycrystalline silicon solar cells (pc-Si solar cells), it exhibits excellent wettability and etching results on the SiNx layer and the Si substrate. The pc-Si solar cells with the as-prepared frit has a better photoelectric conversion efficiency (18.2%) and is 0.8% higher than the solar cells using the conventional frit, which is due to the frit will produce a lot of Ag nanocrystals at the interface of the glass layer, promoting the formation of excellent ohmic contact between the Ag electrode and n-Si layer, and reducing the contact resistance of solar cells.
关键词： Ag-doped glass frit,polycrystalline silicon solar cells,photoelectric conversion efficiency,sol-gel method
更新于2025-09-12 10:27:22
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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) - Characterization of absorption losses in rear side n-type polycrystalline silicon passivating contacts
摘要： Passivating contacts consisting of polycrystalline silicon (poly-Si) and thin silicon-oxide (SiOx) layers facilitate a significant reduction of recombination losses in silicon solar cells. Nevertheless, these gains come with short circuit current density (Jsc) losses due to parasitic absorption by the poly-Si. Even if the passivating contacts are employed at the rear side only, absorption, particularly due to free carriers (FCA) in the heavily doped poly-Si, may still lead to significant Jsc losses. In this work, these losses are characterized as a function of the poly-Si thickness (tpoly) by the analysis of front reflectance spectra in the infrared (IR). For this study, two sets of samples with different n-type full-area poly-Si passivating contacts at the rear are compared to references with a phosphorus(P)-diffused back surface field (BSF) instead. For the two sets, Jsc losses with respect to the references (ΔJsc) are 0.10 mA/cm2 and 0.42 mA/cm2 per 100 nm thick poly-Si, respectively. The difference between the two values is studied by Hall measurements and interpreted to be due to the over three times as high free carrier concentration (ND,act) in the poly-Si layers of the second set of samples as the first set. On the other hand, lifetime measurements showed an excellent passivation yielding an implied open circuit voltage (iVoc) up to 736 mV only for the samples with the more heavily doped poly-Si, whereas iVoc of 683 mV was measured for the first set, which indicates a trade-off between absorption losses and passivation quality.
关键词： infrared reflectance,passivating contacts,solar cells,absorption losses,polycrystalline silicon
更新于2025-09-12 10:27:22
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Comprehensive analysis of blue diode laser-annealing of amorphous silicon films
摘要： The low temperature polycrystalline silicon (LTPS) method has proved to be a technical breakthrough, accomplishing semiconductor thin films with remarkable mobility for a range of high-performance displays, including liquid crystal display and organic light emitting diodes. However, utilizing a conventional excimer laser source for LTPS incurs high cost. In this paper, we demonstrate a comprehensive analysis of the crystallization mechanism of a-Si film (94 nm) and the thermal deformation of the glass substrate induced by Blue diode Laser Annealing (BLA). BLA provides high quality laterally grown crystals over 4 μm × 10 μm on glass substrates, which were examined by optical microscopy, scanning electron microscopy, and Raman spectroscopy. In addition, the permanent deformation introduced by the annealing process is numerically modeled, instantiating how to control the heat conduction from the thin film that affects the substrate. Our findings reveal that the permanent thermal deformation depth that can be obtained is comparable to the roughness of the silicon film for the optimum scanning speed and laser power. The combination of both experimental and numerical results elucidates the manifested physical mechanisms during the BLA process and provides the guidelines to improve the experimental parameters of this process.
关键词： Lateral grain growth,Glass deformation,Silicon thin film,Low Temperature Polycrystalline Silicon (LTPS),Blue diode laser
更新于2025-09-12 10:27:22
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High-performance p-channel thin-film transistors with lightly doped n-type excimer-laser-crystallized germanium films
摘要： High-performance polycrystalline-germanium (poly-Ge) thin-film transistors (TFTs) fabricated with lightly doped Ge thin films by excimer laser crystallization (ELC) and counter doping (CD) have been demonstrated. High-quality n-type Ge thin films with a grain size as large as 1 μm were fabricated by ELC in the super lateral-growth regime and CD at a dose of 1 × 1013 cm?2 or higher. Consequently, a superior field-effect mobility of 271 cm2 V?1 s?1 and a high on/off current ratio of 2.7 × 103 have been obtained for p-channel Ge TFTs with the channel width and length of both 0.5 μm fabricated by ELC at 300 mJ/cm2 and CD at a dose of 1 × 1013 cm?2. The effects of ELC conditions and CD dose on the electrical characteristics of p-channel Ge TFTs were also investigated.
关键词： field-effect mobility,excimer laser crystallization,thin-film transistors,polycrystalline-germanium,counter doping
更新于2025-09-11 14:15:04
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Double-Lattice Magnetoplasmonic Structures Based on BIG and Perforated Gold Films
摘要： A method of manufacturing double-lattice magnetoplasmonic crystals with the structure (Au/BIG)2, in which the plasmon gold lattices are displaced relative to each other by half a period, has been presented. Gold films with thicknesses of about 40 nm have been formed by the ion-beam sputtering–deposition method, while the adhesive properties of the films allow the dimensional etching by a sharp-focused ion beam. It has been shown that the formation of the second plasmon lattice located on top of the 100 nm thick garnet layer allows the preserving of the periodicity of the first Au lattice. However, there is a significant influence of diffusion spreading on the lower lattice material, which leads to a decrease in its density. The dependence of the intensity magnetooptical effect in the geometry on the transmission as a function of the thickness of the upper lattice and presence of an additional layer of Ta2O5 has been studied.
关键词： polycrystalline ferrite-garnet,magnetoplasmonic crystals,magnetooptical effects,deposition,ion-beam methods,sputtering,plasmon resonance
更新于2025-09-11 14:15:04
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All-inorganic Lead Halide Perovskites: A Promising Choice for Photovoltaics and Detectors
摘要： Recent years have witnessed a significant performance breakthrough in all-inorganic perovskite solar cells, but their power conversion efficiencies are still far lower than a theoretical limit and they also suffer from severe moisture instabilities. Based on the discussions on crystal structures, chemical bonds, and optical and electrical properties of all-inorganic perovskites, we have summarized their comprehensive applications in solar cells and detectors. The effects of monovalent and divalent ion doping, morphology, crystallization control and interface engineering on device performance and stability have been carefully evaluated. Narrow-bandgap CsPbI3 polycrystalline bulk film solar cell has achieved the highest power conversion efficiency of 18.4%, while stable CsPbBr3 nanocrystal film is a more successful choice in UV-visible and high-energy ray detections. Finally, we call on boosting the performance and stability of solar cells and shortening response time for tandem photovoltaic and high-speed dynamic detection applications, respectively.
关键词： polycrystalline bulk films,solar cells,All-inorganic perovskites,photodetectors,nanocrystal films
更新于2025-09-11 14:15:04
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Extraction of Uncertain Parameters of Double-Diode Model of a Photovoltaic Panel Using Simulated Annealing Optimization
摘要： In this article, our goal is to improve the estimation of the parameters of solar photovoltaic models by using the simulated annealing (SA) algorithm. The proposed approach takes into account the uncertainties of measurements. This approach consists of three steps. The ?rst is the extraction of the parameters in a conventional manner based on SA. Then, in order to reduce the search interval of parameters, we will determine the uncertainties of the measurements of each parameter. Finally, we will determine the instantaneous parameters, taking into account the results of the ?rst two steps. For the validation of proposed theoretical developments, the proposed approach is applied to two di?erent commercial solar panel parameter estimation problems (the monocrystalline solar module STM6-40/36 and the polycrystalline silicon cells photovoltaic module Sharp ND-R250A5). The results obtained are compared with well-established algorithms to con?rm its e?ectiveness. These comparisons have shown that the proposed method exhibits largely more e?ective performances than existing methods in the literature.
关键词： uncertainties,polycrystalline silicon cells,solar photovoltaic models,simulated annealing,monocrystalline solar module,parameter estimation
更新于2025-09-11 14:15:04
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Performance evaluation of different photovoltaic technologies in the region of Ifrane, Morocco
摘要： This study aims at analyzing and comparing several indices that evaluate the performance of different grid connected photovoltaic technologies, namely amorphous silicon (a-Si), Polycrystalline silicon (pc-Si), and Monocrystalline silicon (mc-Si) generating around 2 kWp each and set up a forecast studies for future perspectives. These technologies are connected to a low voltage (400 V) three phase electrical grid of Al Akhawayn University (33° North, 5° West) facing south on a flat surface, 32° tilted with zero azimuth, and without including any tracking system. This work is done within the framework of Propre.ma project aiming at establishing a photovoltaic yield maps throughout Morocco. The experimental and theoretical horizontal irradiances of Ifrane's region, simulated with the Davies and Hay model on the MATLAB's software, are compared in the following study. Besides, the evaluation of different technologies is based on the (annual/monthly/daily) AC energy output, the performance ratio, the system efficiency, and the capacity factor that are calculated and measured from data gathered between October 2014 and the end of 2018. An economic analysis was carried out in order to define the levelized cost of electricity of the three technologies. Eventually, the obtained results confirm that the polycrystalline technology is the most cost-effective technology for the region of Ifrane.
关键词： Photovoltaic,Polycrystalline,Performance evaluation,Economic analysis,Amorphous,Monocrystalline
更新于2025-09-11 14:15:04
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Mechanism Analysis of PCC Harmonic Resonance Based on Nonlinear Self-Oscillation Concept in a High-Power Grid-Tied Photovoltaic Plant
摘要： Polycrystalline materials can be divided into four types of microstructural components, including grain cell (GC), grain boundary (GB), triple junction (TJ) and vertex points (VP). Nanoindentation at different microstructural components on the polycrystalline materials surface can lead to different plastic deformation behaviors of the polycrystalline materials. Due to experimental limitations, the indentation-induced internal stress and defect evolution process are difficult to investigate directly, especially for the polycrystalline materials with grain size less than 100 nm. The molecular dynamics (MD) simulations were performed to unravel the initial indentation position effect on the elasticity/plastic deformation mechanism of polycrystalline copper. The results reveal that the initial indentation position governs the indentation force variation and defect distribution range due to the different dimensionalities of the microstructural components. The defect propagation as well as the internal stress transmission in the GC regions tend to transfer to the low-dimensional microstructural components of the interfaces. In addition, the atomic internal stress and potential energy accumulation/release of the microstructural component atoms during the nanoindentation process are also investigated, revealing that the atomic internal stress and potential energy in the VPs vary earliest, followed by the TJs, GBs and GCs.
关键词： microstructural component,initial indentation position,molecular dynamics,polycrystalline material,Nanoindentation
更新于2025-09-11 14:15:04