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Structure-design strategy of 0–3 type (Bi0.32Sr0.42Na0.20)TiO3/MgO composite to boost energy storage density, efficiency and charge-discharge performance
摘要： A novel 0–3 type (Bi0.32Sr0.42Na0.20)TiO3/MgO composite is investigated in this work, which possesses a high stored energy storage density ws?2.50 J/cm3, recoverable energy storage density WR?2.09 J/cm3 with high efficiency η?84% under low electric field (20 kV/mm). The excellent performance is owning to the increase of breakdown strength (BDS) value and the intrinsic mechanism for enhanced BDS value by MgO incorporation is disclosed by numerical simulations (COMSOL). Moreover, the studied composite exhibits excellent charge-discharge performance, the current density (CD) and power density (PD) are 1671 A/cm2 and 150 MW/cm3, respectively, which are much superior to that of other ceramics. Besides, most of the stored energy is discharged within ?0.15 μs via charge-discharge tests. This work not only provides a novel technique to designing bismuth-based ceramic capacitors with simultaneously high Wd, η and excellent charge-discharge performance, but also deepens the understandings of the role for the metallic oxide in the composite.
关键词： 0–3 Composite,Energy storage,Numerical simulations,Charge-discharge,Lead-free
更新于2025-11-14 17:28:48
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[IEEE 2018 International Semiconductor Conference (CAS) - Sinaia (2018.10.10-2018.10.12)] 2018 International Semiconductor Conference (CAS) - Interface Trap Effects in the Design of a 4H-SiC MOSFET for Low Voltage Applications
摘要： The current-voltage characteristics of a 4H-SiC MOSFET dimensioned for a breakdown voltage of 650 V are investigated by means of a numerical simulation study that takes into account the defect state distribution at the oxide-semiconductor interface in the channel region. The modelling analysis reveals that, for these low-voltage devices, the channel resistance component plays a key role in determining the MOSFET specific ON-state resistance (RON) under different voltage biases and temperatures. The RON value is in the order of a few mΩ×cm2.
关键词： numerical simulations,power devices,ON-state resistance,4H-SiC,defects states
更新于2025-09-23 15:23:52
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High order harmonic generation in solids: a review on recent numerical methods
摘要： Interaction of intense lasers with solid materials offers an alternative way to achieve high-order harmonic generation (HHG). Since the underlying mechanisms of the harmonic emission remain uncertain, a large number of theoretical studies have been proposed to explain the experimental findings in this fast-growing field. Here, we review the primary numerical methods and present a brief perspective of HHG in solids.
关键词： Ultrafast laser,strong field,numerical simulations,laser-crystal interaction,solid materials,high-order harmonic generation
更新于2025-09-23 15:23:52
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Numerical analysis of single-point spectroscopy curves used in photo-carrier dynamics measurements by Kelvin probe force microscopy under frequency-modulated excitation
摘要： In recent years, the investigation of the complex interplay between the nanostructure and photo-transport mechanisms has become of crucial importance for the development of many emerging photovoltaic technologies. In this context, Kelvin probe force microscopy under frequency-modulated excitation has emerged as a useful technique for probing photo-carrier dynamics and gaining access to carrier lifetime at the nanoscale in a wide range of photovoltaic materials. However, some aspects about the data interpretation of techniques based on this approach are still the subject of debate, for example, the plausible presence of capacitance artifacts. Special attention shall also be given to the mathematical model used in the data-fitting process as it constitutes a determining aspect in the calculation of time constants. Here, we propose and demonstrate an automatic numerical simulation routine that enables to predict the behavior of spectroscopy curves of the average surface photovoltage as a function of a frequency-modulated excitation source in photovoltaic materials, enabling to compare simulations and experimental results. We describe the general aspects of this simulation routine and we compare it against experimental results previously obtained using single-point Kelvin probe force microscopy under frequency-modulated excitation over a silicon nanocrystal solar cell, as well as against results obtained by intensity-modulated scanning Kelvin probe microscopy over a polymer/fullerene bulk heterojunction device. Moreover, we show how this simulation routine can complement experimental results as additional information about the photo-carrier dynamics of the sample can be gained via the numerical analysis.
关键词： Kelvin probe force microscopy,nanostructured photovoltaics,numerical simulations,photo-carrier dynamics,carrier dynamics,carrier recombination,carrier lifetime
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Investigation of Doppler Spectra of Sea Backscatter Through Large-Scale Monte Carlo Simulations: Direct Numerical Solution And Approximate Models
摘要： The study simulates and analyses backscattering of a time-harmonic (continuous-wave) X-band signal from evolving ocean-like surfaces in the 2D space. For the same surface realization, the scattered field is evaluated using the direct numerical solution of a first-principles boundary integral equation, and with two approximate models: the coherent Two-Scale Model (CTSM) and the second-order Small Slope Approximation (SSA2). Large Monte Carlo ensembles are built up to evaluate well-averaged Doppler spectra. The investigation focuses on the two spectral parameters: centroid and width, with alternative definitions for the latter being discussed. A broad and finely sampled range of incidence angles is considered, providing a comprehensive and detailed view at the behavior of these quantities from nadir to low grazing. Using the same set of surfaces when calculating backscattered fields according to the exact and approximate methods provides a rigorous test for the accuracy of the chosen scattering models. The reported high-quality data from direct numerical simulations can serve as a benchmark for other scattering formulations.
关键词： numerical simulations,sea surface electromagnetic scattering,Doppler spectrum
更新于2025-09-23 15:21:21
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[IEEE 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Kyoto, Japan (2018.7.9-2018.7.13)] 2018 31st International Vacuum Nanoelectronics Conference (IVNC) - Discrepancies and universality in the fractional reduction of the apex-field enhancement factor considering small clusters of field emitters
摘要： Numerical simulations are important when assessing the many characteristics of field emission related phenomena. In this work, we analyze the fractional change of the apex-Field Enhancement Factor (FEF), ??, from a single emitter, with apex-FEF ??1, and a pair, with apex-FEF ??2. We show, based on finite element technique, that the functional dependence ??(??) (?? corresponding to the distance between the axis of the emitters) obeys a recently proposed power law decay [1], at sufficient large distances in the limit of infinite domain size, which is not observed by using a long time established exponential decay [2] or a more sophisticated fitting formula proposed recently by Harris et al. [3]. This inverse-third power law functional dependence is respected for various systems like infinity arrays and small clusters of emitters with different shapes. Thus, ??? ～ ?????, with ?? = 3, is suggested to be a universal signature of the charge-blunting (CB) effect in small clusters or arrays, at sufficient large distances between emitters with any shape. These results improve the physical understanding of the field electron emission theory to accurately characterize emitters in small clusters or arrays.
关键词： charge-blunting effect,power law decay,apex-Field Enhancement Factor,field emission,numerical simulations
更新于2025-09-23 15:21:21
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Graphene on an optical waveguide: comparison of simulation approaches
摘要： Recently, unusual properties of novel two-dimensional materials like graphene have revolutionized many branches of science and technology. Adequate numerical simulations of photonic devices comprising graphene layers require new approaches or modified methods. In this paper we present comparison of results obtained with three representations of a graphene monolayer: (1) an infinitely thin sheet with a finite surface complex conductivity, (2) a thin layer of a finite thickness exhibiting uniaxially anisotropic complex permittivity, and (3) anisotropic permittivity perturbation in an infinitely small volume. Numerical solutions of rigorous dispersion equations were compared to each other and also with the results obtained with several commercial as well as proprietary software packets. Under proper conditions, all approaches provide comparable results.
关键词： Perturbation method,Volumetric method,Optical waveguides,Graphene,Boundary condition method,Numerical simulations
更新于2025-09-23 15:21:01
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Numerical Investigation of the Impact of ITO, AlInN, Plasmonic GaN and Top Gold Metalization on Semipolar Green EELs
摘要： In this paper, we present the results of a computational analysis of continuous-wave (CW) room-temperature (RT) semipolar InGaN/GaN edge-emitting lasers (EELs) operating in the green spectral region. In our calculations, we focused on the most promising materials and design solutions for the cladding layers, in terms of enhancing optical mode con?nement. The structural modi?cations included optimization of top gold metalization, partial replacement of p-type GaN cladding layers with ITO and introducing low refractive index lattice-matched AlInN or plasmonic GaN regions. Based on our numerical ?ndings, we show that by employing new material modi?cations to green EELs operating at around 540 nm it is possible to decrease their CW RT threshold current densities from over 11 kA/cm2 to less than 7 kA/cm2.
关键词： edge-emitting lasers,InGaN/GaN,numerical simulations,semiconductor devices
更新于2025-09-23 15:19:57
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High‐Efficiency Interdigitated Back Contact Silicon Solar Cells with Front Floating Emitter
摘要： Silicon interdigitated back contact (IBC) solar cells with front floating emitter (FFE-IBC) put forward a new carrier transport concept of “pumping effect” for minority carriers compared with traditional IBC solar cells with front surface field (FSF-IBC). Herein, high-performance FFE-IBC solar cells are achieved theoretically combining superior crystalline silicon quality, front surface passivation, and shallow groove structure using 2D device model. The improvement of minority carrier transport capacity is realized in the conductive FFE layer through optimizing the doping concentration and junction depth. It is shown that the shallow groove on the rear side of FFE-IBC solar cells can effectively enhance the carrier collection ability by means of minimizing the negative impact of undiffused gap or surface p–n junction. The high efficiency exceeding 25% can be realized on silicon FFE-IBC solar cells with the novel cell structure and optimized cell parameters, where the back surface field and emitter region width can be made for the same with only a slight sacrifice of photocurrent density and conversion efficiency. It is demonstrated theoretically that the realization of high-efficiency and low-cost silicon IBC solar cells is feasible due to the increase of the module fabrication tolerance.
关键词： shallow grooves,numerical simulations,high performance,front floating emitters,silicon interdigitated back contact solar cells
更新于2025-09-19 17:13:59
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On the issue of neutron source development for a laser-driven nuclear-thermonuclear reactor
摘要： We discuss the feasibility of developing a high-power thermonuclear neutron source driven by laser pulses. Using one-dimensional numerical simulations for targets made in the form of double-sided cones, for an absorbed Nd-laser energy of ~ 1 MJ (at the second and third harmonics) and pulse duration of 10 – 20 ns it is possible to achieve a neutron yield at a level of 1016 – 1017 per shot. This neutron yield is a prerequisite to the commencement of work to develop a hybrid nuclear-thermonuclear reactor.
关键词： numerical simulations,conic target,neutron source
更新于2025-09-16 10:30:52