Journal of Computational Electronics最新文献

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.

A double-barrier quantum well is created using a larger band gap V-cut modified armchair graphene nanoribbon (AGNR) for the barrier region and a pristine AGNR with a smaller bandgap for the channel region. The numerical non-equilibrium Green’s function (NEGF) method, based on the pi-orbital tight-binding model, is employed to study the quantum transport properties of the device. The effects of various dimensional parameters, such as contact width, channel length, and distance between V-cuts in the barrier region, are investigated. The plot of the local density of states (LDOS) shows the formation of a single quantized quasi-energy state in the channel region, corresponding to a peak in transmission. The V–I characteristics of the device exhibit negative differential resistance (NDR) regions for a certain range of bias values. This device’s resonant tunneling performance parameters are compared with those of a similar, previously reported structure.

This paper presents a novel photonic crystal structure for designing all-optical photonic crystal logic gates and functions based on threshold logic concept. The structure offers two- and three-input AND/NAND logic gates as well as three-input majority/minority functions. In this method, the summation of inputs values connects to a threshold detector with varying threshold values in order to achieve different logic gates and functions. Furthermore, the impact of variations in the diameter and position of rods on the performance of the proposed structures has been examined. Simulation results demonstrate the successful operation of the proposed structures even in the presence of 14% variation in rod diameter, indicating that the presented logic gates exhibit minimal sensitivity to process variations. The finite difference time domain method was used to evaluate the performance of the proposed structures with a switching power requirement of is 2.5 W.