Journal of Computational Electronics最新文献

In this paper, the characteristics of the fundamental mode of surface plasmons in a circular cylindrical three-layer graphene waveguide structure are investigated. By using Maxwell equations in the cylindrical coordinate system and applying the boundary conditions, the dispersion relation has been derived for the fundamental mode. In the proposed model, along with the electric field distribution in the waveguide, the effect of different model parameters on the dispersion curve has also been investigated. For instance, the effect of chemical potential, temperature and the separation between the first-second and second-third layers of the graphene has been shown and discussed in detail. Furthermore, the effect of chemical potential, temperature and separation between the first-second and second-third layers of the graphene on the propagation length and phase speed is also discussed.

The pursuit of increasingly efficient and cost-effective solar energy solutions has driven significant advancements in photovoltaic (PV) technologies over the past decade. Among these innovations, bifacial solar cells, which capture sunlight from both the front and back surfaces, with front surface texturing and rear-side optimization playing crucial roles, present a promising avenue for enhancing efficiency compared to conventional designs. The effectiveness of these cells, however, is largely dependent on the optimization of rear surface properties and the material characteristics employed. This study investigates into the pivotal role of surface texture, particularly on silicon wafers, in shaping key performance metrics such as open-circuit voltage, short-circuit current, fill factor, and overall efficiency. Given the complex interdependencies among these parameters, machine learning (ML) tools, specifically random forest regression models, have been utilized to decode these intricate relationships. The findings underscore the significance of surface texture in modulating reflectance from both the rear and front surfaces, which in turn influences the overall performance of the solar cells. By applying ML models, this research provides an improved understanding of the impact of surface characteristics, thereby offering valuable insights into the optimization of design and material selection for next-generation high-performance solar cells. This ML optimization study indicates that the pyramid structures with a height of 3 μm and a base angle of 62° can significantly reduce reflectance to 9% while maximizing solar cell efficiency to 23.61%, marking a substantial advancement over existing designs. This model achieves 75% accuracy on synthetic test data and 78% on experimental data reinforcing model’s applicability despite typical ML limitations in PV systems.

This study introduces a distinctive entwined photonic crystal fiber (PCF) featuring two distinct and independent directed mode sections, collectively supporting a total of 112 orbital angular momentum (OAM) modes, comprising 76 + 36 modes. The confinement loss (CL) ranges approximately between (2.49701times 1{0}^{-11}) and (9.13425times 1{0}^{-9} text{dB}/text{m},) while highest attained OAM purity is (99.31969%) and (98.99258%) at (H{E}_{2, 1}) mode, respectively, for both inner and outer rings. All the modes demonstrate ERIDs exceeding (1{0}^{-4}), and minimum dispersion variation observed is (-856 text{ps}/text{km}-text{nm}). Additionally, we achieved an outstanding isolation performance with the highest attained ISO reaching (294 text{dB}) at ({text{HE}}_{9, 1}) mode and observed a substantial effective mode area of 9.15 μm² and 25.8μm², respectively, for inner and outer rings. This research leverages COMSOL Multiphysics' finite element method (FEM) and perfectly matched layer (PML) capabilities alongside MATLAB processing to calculate all key properties of the proposed fiber. Therefore, the suggested PCF demonstrates promising prospects for extended-range, high-capacity data transmission within optical communications and applications related to OAM sensing.

This study investigates the influence of external hydrostatic pressure on the mechanical, electronic, and magnetic properties of cubic GdAlO₃ using density functional theory (DFT) and Monte Carlo (MC) simulations. Mechanically, upon pressure increase, a sizable increase in the elastic constants C₁₂, C₁₁, and C₄₄, as well as in bulk, Young's, and shear moduli of GdAlO_3, is observed. This indicates an enhanced stiffness and resistance to deformation upon pressure increase. The band gap shows a notable increase in pressure, which is useful in tuning the electronic properties of specific electronic devices for potential applications. In addition, a stable overall magnetic moment is observed under pressure variation, with increased exchange interaction parameters for Gd-Gd pairs, indicating more robust ferromagnetic ordering. Furthermore, the Monte Carlo simulation revealed increased Curie temperature (T_C) from 67K at 0 GPa to 142K at 90 GPa, underscoring strengthened magnetic interactions and thermal resilience under compression.

Metal chalcogenide perovskites have a number of benefits over lead-halide perovskites, including superior moisture resistance, light-induced degradation together with nontoxic elemental composition, higher absorption, and exceptional carrier transport properties. These materials have orthorhombic phase Pnma and are potential candidate materials to be used as absorber materials in solar cells. In this study, we propose metal chalcogenide perovskites CaZrX₃ (X = S, Se) as a candidate absorber material. Therefore, the investigation of the structural, electrical, optical, thermal, and thermoelectric properties of CaZrX₃, where X = S, Se, is being carried out using first principles methods. These proposed semiconducting compounds will meet the requirement for stability against volume change. These materials show a direct band gap of 1.812 eV and 1.117 eV at the Γ point. To better understand the optical transitions in the material, the real and imaginary parts of the dielectric function have been calculated. The remarkable absorption coefficient ((alpha )) exceeding 10⁵ cm⁻¹ above photon energy exceeding bandgap indicates that the materials are suitable for the visible light absorption. For the estimation of photovoltaic performance of CaZrX₃ (X = S, Se) and to demonstrate the high photo-absorptivity, the spectroscopic-limited maximum efficiency has been calculated. The results show a maximum photovoltaic efficiency of 26.4% and 32.4% for CaZrS₃ and CaZrSe₃ respectively at the thickness L = 100 nm. We have also calculated the thermoelectric coefficients. These perovskites are gaining more attention as a thermoelectric material because of their higher Seebeck coefficient, and ultra-low thermal conductivity.

Recent advances in VLSI technology have led to the introduction of Quantum dot Cellular Automata (QCA) technology as a possible alternative to CMOS technology. This is owing mostly to its tiny feature size, high operating frequency, and low power consumption. During the preliminary research stage, QCA has been used to execute diverse models of combinatorial and sequential circuits, which serve as the fundamental functional components in a wide range of applications. Currently, research is focusing on the implementation of application-oriented architectures using QCA. The motivation behind this research work is to incorporate Galois Field (GF) functions into the AES Mix- Columns operation. We have proposed an Xtime multiplier implemented using QCA technology and analyzed the multiplier using various XOR models of QCA.

The concept of optical switching utilizing directional couplers and the electro-optic effect has been leveraged to design various sequential circuits. By applying an appropriate voltage to the core of the couplers, switching of optical pulse signals is achieved through optical tunneling phenomena. This paper presents a comprehensive mathematical analysis of electro-optic effect-based switching, demonstrating its efficacy through 3-D MATLAB simulations of the optical switch layout. A clocked D flip-flop, incorporating an optical delay unit, is examined using 3-D numerical simulations, illustrating the spatial propagation of optical pulses and providing time domain plots for verification. Employing the proposed clocked D flip-flop as a basic module, optically clocked ripple up/down-counters are implemented. Additionally, the design and analysis of an optical 4-bit shift register are discussed, showcasing its ability to effectively shift pulses via 3-D simulations of optical field propagation and time domain plots. This study presents a comprehensive analysis of the extinction ratio, contrast ratio, and amplitude modulation characteristics of the proposed optical code converter circuit. These findings offer an effective methodology for implementing both basic sequential models and complex optical circuits.

The computational characteristics of the fast Fourier transform associated with real-time information signals using traditional techniques is deemed the maximal hardware void with peak power consumption, which is an essential task for any researchers while illustrating the designs of architectures in very large-scale integration circuits. The proposed scheme associated with the pipeline reduces the time of processing at the cost of several registers, and to ensure the efficient contribution for reducing the power, the modification over the complex and critical multiplier has been introduced with minimal internal real-time multipliers, which in turn is reconstructed by canonical signed digit multipliers with the adaptation over the technique of resource sharing. The verification of the results of experimentation has been made. It is inferred that the proposed incorporated design is highly efficient regarding area, speed, and power compared to state-of-the-art techniques.

In this paper, a metal–insulator–metal (MIM) array nanostructure consisting of a bowtie aperture and cylindrical holes is proposed as a field amplifier. This hybrid array consists of a grating film made of gold in which some cylindrical holes are replaced with a bowtie aperture, sapphire substrate, and finally a metal film. The array of cylindrical holes acting as a two-dimensional grating can effectively excite propagating surface plasmon polariton modes along a metal film, but the electric field enhancement inside it is relatively weak. On the other hand, the bowtie aperture, with its sharp corners and small gap, can provide a greater intensity enhancement factor within its gap. The combination of these two MIM nanostructures forms a strong coupling between the propagating and localized surface plasmons, leading to an improvement in field confinement in the bowtie aperture in the sub-diffraction limit and its magnitude increase of 115 times. This effective enhancement can be used in plasmonic sensors, lasers, SERS, etc., applications.

Quantum confinement effects (QCEs) are significant in tunnel field-effect transistors (TFETs) since their operation is based on the mechanism of band-to-band tunneling. This study presents a simple approach for integrating QCEs into the semiclassical TCAD simulations of TFETs. The approach was based on a post-processing computation in which 1D Schrodinger equations were first solved manually, then their solutions were used to modify the conduction and valence band profiles in the 2D TCAD simulations. For each bias condition, only a 1D potential profile at the position of the maximum tunneling generation was adopted to describe the QC through the solutions of Schrodinger equations for electrons and holes. The quantum-simulated results based on this simple method show good agreements with both quantum–mechanical simulations based on a sophisticated approach and experimental data. The analyses also show that the van Dort quantum model available in commercial TCAD simulators is not appropriate for describing QCEs in TFETs. The approach can be practically employed in studying the influences of QCEs on the electrical characteristics, in particular the dependence of QCEs on the body thickness of TFET devices.