Journal of Computational Electronics最新文献

This paper introduces a SPICE-compatible photonic–electronic co-simulation framework based on the complex vector fitting (CVF) algorithm, developed for accurate representation of multi-wavelength behavior in linear and passive photonic integrated circuits (PICs). The proposed wavelength-tunable equivalent circuit models feature a fixed network topology, yet comprise components whose values are parameterized with respect to the optical carrier frequency. This enables both frequency- and time-domain simulations at arbitrary wavelengths, making the framework particularly suited for modeling multi-wavelength photonic systems. To support intricate co-simulation with electronic subsystems, a novel interface circuit is introduced, allowing seamless interconnection with third-party active and passive SPICE models. The capability of the framework to capture complex photonic–electronic interactions is demonstrated through three application examples, highlighting its effectiveness for co-simulating photonic devices with control and receiver electronics.

This paper presents a novel GaAs/AlGaAs-based Quantum Well Photodetector (QWP) for Terahertz (THz) detection. The photodetector is optimized to operate in the 3.9–4.6 THz frequency range, with peak performance at 4.3 THz (69.7 µm). The performance of the QWP is analyzed in terms of quantum efficiency, responsivity, dark current, and capture probability in the high-frequency terahertz region using simulation tools MATLAB and TCAD. The optimized structure corresponds to a quantum well width of L_w = 180 Å and an aluminum mole fraction of x = 0.019, yield a high responsivity of 0.31 A/W, a low dark current of 0.99 mA, and a nearly constant capture probability 0.351 in the 3.9–4.6 THz range. These optimized values lead to enhanced wavelength detection sensitivity of the device, which arises from improved carrier transport, higher electrical conductivity, and stronger photoconductive gain. The simulation results are consistent with previously reported experimental studies, confirming the validity of the proposed model. The developed QWP demonstrates promising potential for next-generation terahertz applications, including 6G wireless and satellite communication systems. A key novelty of this work lies in the optimized GaAs/AlGaAs quantum well parameters, which improve responsivity, and quantum efficiency and reduce dark current for THz detection. Notably, the capture probability's slope remains negative and decreasing with quantum well width and exhibiting a low constant value between 3.9–4.6 THz. This observation is believed to enhance the electrical conductivity of the detector and hence, its gain increases. This study presents a novel observation and is being reported for the first time. The developed model is a strong contender for high-speed free-space optical and wireless communications.

This study presents a novel microwave absorber design based on the Aizawa chaotic system, with deep analysis through mathematical modeling, simulation, and experimental analysis. The chaotic dynamics are used to generate complex fractal patterns with broadband absorption potential, derived via numerical solutions and processed with the 2D Julia set algorithm. Advanced image processing techniques further refine these patterns with high precision. The optimized fractal pattern is then transferred into an electromagnetic simulation environment to assess its wideband absorption capabilities. The absorber is fabricated by printing a resistive ink pattern (0.04 mm thick) onto an RO3003 substrate (0.51 mm thick), chosen for its flexibility and balanced electromagnetic performance. An equivalent circuit model is also developed to evaluate resistive, inductive, and capacitive properties, it follows a parametric study on material optimization. Simulations demonstrate effective absorption across the 1.82–34 GHz range, and measurements in the 3–34 GHz range using horn antennas show strong harmony with the simulation results. Compared to similar designs, this absorber demonstrates superior broadband performance.

In this research, a new structure of the Feynman gate based on two-dimensional photonic crystals is designed and simulated. Our circuit is simpler and smaller because we have not included a ring resonator in its design. The optical propagation time is shortened by not using the resonator ring. Additionally, this structure has increased the speed of data transmission. We used linear and point defects based on the Feynman gate accuracy table while simulating the design. The gate has a working wavelength of 1550 nm, and zero and one are determined by the amount of light that reaches the outputs. These devices make designing processors with high speed and low power consumption possible. By removing the ring resonator from our simulation, we were able to include one of the significant design considerations for optical gates: achieving small dimensions.

Research on designing compounds with effective nonlinear optics responsiveness is fascinating. The present research examines how quinacridone can improve nonlinear optical characteristics in conjugated D-π-A and D-π-A-π-A systems based on ferrocene. Through an analysis of the photophysical behavior, theoretical calculations, and structural features, we uncover notable increases in higher-order hyperpolarizabilities (β, γ) and polarizability (α). New quinacridone-based (FR1-FR8) compounds are designed with the demand and uses of NLO materials in mind. The Nd:-YAG laser with a fundamental wavelength of 1064 nm is used to calculate the frequency-dependent NLO response of R (ferrocene as donor and cyanovinylene as acceptor with phenyl as π-spacer) compound. The theoretical calculation of the absorption maximum λ_max of reference compound (R) was 389 nm, while the experimental calculation was 365 nm. The experimental calculation produced Eg = 2.76 eV, but the theoretical prediction of the energy gap of R was Eg = 2.98 eV. The theoretical and actual values of β frequency-dependent second-harmonic generation (SHG) for R were 1.46 × 10^–30 esu and 10.49 × 10^–30 esu, respectively. The CAM (Coulomb-attenuating method)-B3LYP functional with gen 6-311G (d,p)//cc-pVDZ basis set was utilized for additional theoretical investigation because the results were close to the experimental results. Every chemical from FR1 to FR6 was exhibiting an improved NLO response. Their β values increased from 208.92 × 10^–30 to 6822.86 × 10^–30 esu, while their energy gap Eg decreased from 2.38 to 1.40 eV. γ values were also computed to support the NLO response. With a maximum β = 6822.86 × 10^–30 esu, FR7 was deemed the most appropriate material for NLO response out of all the designed derivatives. Thus, quinacridone has been used to improve nonlinear optical responses by stabilizing the electronic state and facilitating intramolecular charge transfer. Our results imply that novel materials with improved performance for optical applications can be designed by utilizing the synergistic impact of ferrocene and quinacridone.

Graphical abstract

Double-junction tandem solar cells (TSCs) outperform single-junction photovoltaics by combining a wide-bandgap top cell and a narrow-bandgap bottom cell. Potassium-based double perovskites, K₂XAuCl₆ (X = Al, Ga), are investigated for sustainable energy applications using WIEN2k and SCAPS-1D simulations. Stability is verified via tolerance factor and formation energy analysis, while electronic structure studies reveal suitable bandgaps, except for K₂GaAuCl₆ under PBE. Optical evaluations show strong visible absorption, and thermoelectric analysis indicates high ZT values with excellent mechanical properties. SCAPS-1D simulations demonstrate that the tandem design achieves a J_SC of 12.85 mA/cm², V_OC of 2.20 V, and a superior PCE of 22.39%, outperforming individual subcells. These results highlight K₂XAuCl₆ as a prospective material for future-generation inorganic perovskite solar cells.

Two dimensional (2D) materials carry great potential for future nanoelectronics and optoelectronics applications. These applications are very much based on the electrical properties of 2D materials. Therefore, study of the important properties of such materials is necessary for active advancement in the field. Based on this understanding, our work focuses on the study and comparison of the optical characteristics of MoTe₂, hetero bilayer 2H-type MoTe₂/MoSe_2, and MoTe₂/WSe₂ double gate MOSFET (DGMOSFET) photodetectors in the near infrared region (212-400 THz). A hybrid simulation method that uses both QuantumWise ATK and Sentaurus TCAD is used for the study. In this method, first the electrical parameters such as bandgap, effective mass, and mobility of 2H-bilayer MoTe₂ and heterobilayer MoTe₂/MoSe₂ and MoTe₂/WSe₂ are obtained using the QuantumWise ATK. Second, they are transported to Sentaurus TCAD for device simulation. To obtain accurate device characteristics, appropriate models such as the kinetic velocity model (KVM) and quantum model to account for the ballistic mobility and quantum effects in the device are used in TCAD to account for the ballistic mobility and quantum effects. The drain current characteristics, electric field, threshold voltage, electron concentration, and electron mobility are obtained for the photodetectors. Other parameters such as sensitivity, responsivity, quantum efficiency, and signal-to-noise ratio (S/N) of the photodetectors have also been estimated. The heterostructure MoTe₂ DGMOSFET offers superior performance with higher I_on/I_off ratio (67.713 × 10⁵ A/µm), sensitivity, and responsivity.

Solar cells in space are exposed to high-energy particles and ionizing radiation, which aggravate stability and exacerbate lattice defects which are detrimental to performance. A computational analysis of the radiation hardness of kesterite CZTS-based solar cells for their potential application in space is undertaken. We simulated the CZTS degradation under radiation using experimentally reported donor–acceptor defect pairs. Under proton irradiation, the deterioration pattern of CZTS current–voltage characteristics exhibited a significant decrease in short-circuit current (J_SC) and a slight reduction in open-circuit voltage (V_OC) with increasing fluence. Performance decay is observed for fluence beyond 10¹⁴ particles/cm². The simulated results provide a qualitative representation of CZTS degradation under 1 MeV proton irradiation, highlighting its remarkable radiation resistance. Simulation results substantiate the pragmatic prospects of CZTS space applicability.

In this work, we examine the transmission spectrum and band structure of a one-dimensional (1D) periodic structure composed of loops and resonators. This structure exhibits passbands separated by wide band gaps in which the propagation of electromagnetic waves is forbidden. In particular, the number of passbands and band gaps increases with the values of the system’s geometrical parameters. Furthermore, the insertion of defects at the level of the loops and resonators leads to the appearance of one or two highly localized modes within the band gaps. These modes are characterized by high transmission rates (greater than 50%) and are highly sensitive to the geometrical parameters of the structure. Their number depends on the number of introduced defects. This structure enables the design of a high-performance multi-frequency filter. The results are obtained using the Green’s Function Method (GFM) and validated through electromagnetic simulations using the Finite Element Method (FEM).

Organic photodetectors (OPDs) have attracted significant attention owing to their flexible structures, high operational capabilities, and potential for low-cost fabrication, making them promising candidates for next-generation optoelectronic applications. Herein, we investigated a novel OPD configuration comprising a PTB7-Th:PC71BM matrix blended with BPQDs with GO as hole transport layer (HTL) and PDINO as electron transport layer (ETL). The optimized OPD achieved a responsivity of 0.33 A/W coupled with a detectivity of 3.35 × 10¹² Jones. The device demonstrated a short-circuit current density (J_sc) of 19.35 mA/cm², an open-circuit voltage (V_oc) of 0.89 V, and a fill factor (FF) of 68.06%, resulting in a power conversion efficiency (PCE) of 11.75% under AM 1.5G illumination (100 mW cm⁻², 300 K). The incorporation of BPQDs into PTB7-Th:PC71BM resulted in superior charge transport capabilities and reduced recombination, which improved the device performance metrics. Machine learning-assisted modeling revealed that ensemble algorithms significantly enhance the predictive accuracy of the photodetector responsivity. Random Forest Regression achieved the highest performance, with an MSE of 0.0001362, RMSE of 0.0117, and R² of 0.9108, followed by XGBoost with an R² of 0.9028. Feature importance analysis identified the active-layer thickness (t-active) and HTL thickness (t-htl) as the most influential parameters. These findings underscore the value of combining simulations with machine learning to optimize organic photodetector design.