Journal of Computational Electronics最新文献

Hydrogen sensors utilizing field-effect transistors (FETs) have been extensively researched in the past few decades. Silicon-based H₂ gas sensors have shown excellent performances. The next generation sensing and computing technologies demand scaling of semiconductor devices for high-density integration and inclusive performance enhancement. However, the dangling bonds and high surface scattering of silicon have restricted its application in an ultra-scaled domain. Thus, in this article, we propose an electrically doped MoTe₂-based H₂ gas sensor. We have used an analytical model to capture variation of work function with gas pressure. Next, technology computer-aided design (TCAD) tools are adopted to investigate the device performance. To understand the quantum transport in sub-10 nm MoTe₂ channel, non-equilibrium green’s function (NEGF) method is deployed. The study exhibits the high potentiality of electrically doped 2D material like MoTe₂-based H₂ sensors which may spur future experiments.

This study investigates the complete failure evolution mechanism in a pseudo-high-electron-mobility transistor (pHEMT) under L-band high-power microwave (HPM) injection, which is revealed to follow the pattern “field breakdown triggering-electrothermal coupling-thermal runaway,” breaking through the traditional understanding that attributes the damage mechanism simply to either field breakdown or thermal breakdown. By improving the multi-physics field algorithm and combining circuit device co-simulation, a pHEMT damage model under high-voltage conditions was established. The research shows that when the critical power threshold is exceeded, field breakdown first occurs inside the device, and hotspots form under the gate on the source side, which in turn triggers thermal runaway. By analyzing the evolution laws of carrier concentration, electric field, and ionization rate, the dynamic process of failure is clarified. Experimental verification indicates that the damaged low-noise amplifier exhibits irreversible gain reduction and S-parameter degradation. This finding provides a theoretical basis for failure prediction and protection design for high-reliability radio frequency systems.

A graphene channel Z-shaped tunnel field-effect transistor (GC-ZTFET) sensor is proposed in this research for detecting hydrogen gas. Faster charge transport and more effective drain current modulation are made possible by graphene’s high carrier mobility and superior electrical conductivity. The unique Z-shaped gate structure efficiently enhances the electric field and interband tunneling rate within the channel region. A palladium metal with a suitable work function is considered as the gate catalyst for better gas sensing. The gas sensor modifies the flat band voltage and capacitance–voltage properties through the adsorption of gas atoms at the interface. This alternately affects the drain current, which is used as a sensing metric. The gas sensitivity is estimated in terms of drain current and current ratio. The suggested gas sensor offers greater sensitivity than TFET and Z-TFET. At HP = 10^–10 torr, the GC-ZTFET exhibits a higher peak current sensitivity of 2.86 × 10³, which is seven times and more than one decade higher than the results in the case of Z-TFET and TFET. It also exhibits exceptional sensitivity to very low gas pressures, making it a promising candidate for advanced gas sensor technologies. The sensitivity analysis is also expanded to explore the effects of variation in temperature and trap charge carriers at the catalyst-gate interface.

Multi-band semiconductors are promising candidates for high-efficiency photovoltaic devices. Various technological methodologies have been explored and put into practice. However, the efficiencies achieved experimentally fall short of expectations. In this study, considering the relative scale of all inter-band absorption coefficients, it has been determined that the anticipated efficiencies are difficult to attain. Furthermore, with all the results and considering the mathematical and boundary properties, a fit as a function of the absorptivities for efficiencies and energies of all examined multi-band solar cell types has been obtained.

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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.

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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.