Journal of Computational Electronics最新文献

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.

In this research, an efficient two-valley Monte Carlo model simulates the Schottky junction. Impurity and phonon scatterings are considered, and impact ionization is included in the scattering matrix. Non-parabolic energy bands are assumed, and tunneling and thermionic emission are the current components. By adding a thin layer, it is shown that the formation of an electric field opposite to the electron motion direction at the junction boundary increases the effective height of the Schottky barrier. By changing the impurity concentration density of this thin layer, the change in the effective height of the Schottky barrier and consequently the simulated passing current is studied. A comparison of the results obtained from the simulation with valid scientific data confirms the correctness of the presented model. The proposed model can be widely used in the analysis of Schottky-based devices.

The present work aims at developing a new design strategy based on optimizing light trapping management in the CsSnI₃ perovskite active layer using back groove engineering, to tune the broadband photoresponsivity. To do so, an extensive numerical simulations based on 2D-Finite Difference Time Domain (FDTD)-SILVACO calculations are carried out to assess the optoelectronic properties of the proposed sensor, including the impact of back grooves engineering. The effect of the groove geometry on the photosensing characteristics of the photodetector (PD) is analyzed. It is found that the depth, width and the period of the back grooves can modulate the optical behavior of the CsSnI₃ perovskite active layer, showing a great potential for improving the light harvesting capabilities over a wide spectral range. A Genetic Algorithm Optimization (GAO) technique is implemented to find out the best groove geometry and period, offering the highest photoresponse over UV to NIR spectral bands. The obtained results show the ability of the proposed strategy to improve and tune the optoelectronic properties of the device, demonstrating a high responsivity of 78 mA/W and an improved I_ON/I_OFF ratio of 61 dB. Therefore, the proposed approach can open new paths to enhance the optical and electrical performances of thin film perovskite photodetectors by optimizing the light trapping management using back groove engineering and metaheuristic calculations.

This study introduces a dual core photonic crystal fiber (DC-PCF) based biosensing approach for early detection of malaria in individuals by monitoring the variations in the red blood cells (RBCs). The proposed DC-PCF comprises four layers of a hexagonal lattice with circular air holes. In the proposed DC-PCF, we have used a central elliptical hole to infiltrate RBCs samples. The proposed study helps to detect various stages of malaria, such as infected RBCs, including the Ring stage, Trophozoite stage, and Schizont stage, by analyzing the changes in the peak wavelength. The proposed refractive index (RI) based sensor is designed to operate within an RI range of 1.33 to 1.41, enabling the detection of malaria. The numerical analysis indicate that our biosensor demonstrates significant sensitivity across different stages, such as 12,00000 nm/RIU for the ring stage, 11,15,263.15 nm/RIU for the trophozoite stage, and 11,13,793.10 nm/RIU for the schizont stage under x-polarization. Similarly, under y-polarization, the sensitivity is observed to be 10,50,000 nm/RIU for the ring stage, 10,54,736.84 nm/RIU for the trophozoite stage, and 10,32,758.62 nm/RIU for the schizont stage. The proposed DC-PCF-based biosensor is highly suitable for biological analysis and early malaria detection because it has a low detection limit and superior sensing performance.

We use an improved shift operator finite-difference time-domain (ISO-FDTD) algorithm, previously proposed by others, to further process more complex dielectric functions including critical models and several higher-order Lorentz models that we fitted ourselves. These function models have a total of 6–8 sub-terms, and each sub-term consists of two complex poles (Lorentz model). This work supports the universal applicability of the ISO-FDTD algorithm for processing higher-order complex dispersive materials. We applied this ISO-FDTD algorithm in split-field FDTD (SF-FDTD) to simulate dispersion media under oblique incidence. The simulation results agree well with the analytical solutions. Thus, this approach provides researchers with an alternative option apart from auxiliary differential equations (ADE) or piecewise linear recursive convolution (PLRC) methods when processing high-order dispersive media in SF-FDTD.