Journal of Computational Electronics最新文献

In this paper, based on the first-principles calculation method of density functional theory, the PtS₂/PtSe₂ heterostructure with the lowest formation energy is selected from five different stacking modes. At the same time, the phonon spectrum of PtS₂/PtSe₂ heterostructure has no imaginary frequency, so the structure is stable. After that, the changes of photoelectric properties of heterostructures under tensile and compressive strains were studied. It is concluded that the PtS₂/PtSe₂ heterostructure is a semiconductor with indirect band gap and type II band arrangement. With the increase of tensile strain, the band gap value decreases from 0.927 to 0.565 eV, and the minimum value of the conduction band is transferred from the high symmetry point M point to the K point by 8% biaxial tensile strain. The biaxial tensile strain can effectively improve the dielectric constant of the PtS₂/PtSe₂ heterostructure. When the strain reaches 8%, the dielectric constant is nearly twice as high as the intrinsic value and reaches 11.6, which improves the charge retention ability. The light absorption of PtS₂/PtSe₂ heterostructure reaches 13.7 × 10⁴ cm⁻¹ under compressive strain, and the stability of light absorption is enhanced. The optical reflection ability of PtS₂/PtSe₂ heterostructure is significantly enhanced under tensile strain, indicating that the biaxial strain has a regulatory effect on the absorption and reflection ability of light. The valley values of all systems near the ultraviolet region show a linear increase trend, which changes the transmittance of the heterostructure. These findings broaden the application of PtS₂/PtSe₂ heterostructures in optoelectronic engineering.

In this work, the influence of heavy ions on the performance mechanism of recess gate GaN/AlN-based p-channel HEMT has been investigated using extensive TCAD simulation. The effect of the recess gate depth and position along with the technological misalignment issues has also been addressed. Results show that the transient drain current is more sensitive to heavy ions when it is incident in the gate–drain access region. Also, the device exhibited high susceptibility to heavy ions, with increasing energy and recess gate depth. With the increase in linear energy transfer (LET) value, the peak gate and drain current increase linearly. Further to make the device more robust against heavy ions, MIS-type configuration in GaN/AlN architecture is studied with silicon nitride as the dielectric layer. The insulating layer provides an additional degree of protection against the single-event effects caused by heavy ions or other sources of charge injection mechanism.

We present the characterization of seven newly developed organic dyes tailored for application in dye-sensitized solar cells (DSSCs). At the core of their structures is 8,10-di(thiophen-2-yl) trithieno[3,4-b:3′,2′-f:2″,3″-h] quinoxaline, serving as the electron-donor group across all dyes. Employing density functional theory (DFT) and time-dependent DFT (TD-DFT) techniques with the CAM-B3LYP level and 6-31G(d,p) basis set, we delved into molecular structures, frontier molecular orbitals (FMOs), and various electronic chemical properties. This investigation is aimed at unraveling their ultraviolet–visible (UV–Vis) absorption properties, electron injection free energy, and global hardness (η), electronegativity (χ), and chemical potential (µ). These insights shed light on the stability and potential utility of these dyes as sensitizers in DSSCs. Furthermore, computation and discussion of the open-circuit voltage (({V}_{OC})) underscored the promising nature of these seven new organic dyes with D-A molecules, positioning them as strong contenders for DSSC applications, all anchored around 8,10-di(thiophen-2-yl) trithieno[3,4-b:3′,2′-f:2',3″-h] quinoxaline as the electron-donor group.

Here, the electronic conductance characteristics of naphthopyran were studied using non-equilibrium Green’s function density functional theory (NEGF-DFT) and time-dependent density functional theory (TD-DFT) methods. When naphthopyran is exposed to UV or visible light, the specified structure can switch between its open and closed forms. Molecular geometries, surface material types (platinum, gold, and silver), switching ratios, gaps between HOMO and LUMO levels, transmission spectra, and PDOS at different bias voltages were studied. It was found that the conductance of naphthopyran changed from an off-state (high resistance) to an on-state (low resistance) when the molecular optical junction converted from the open to the closed configuration.

The current study delves into the physical properties and hydrogen storage capabilities of XScH₃ (X = K, Na) using the CASTEP code by leveraging the GGA-PBE method. The examined values of the lattice constants for KScH₃ and NaScH₃, are 4.19 and 4.07 Å, respectively. With a zero band gap revealing the metallic behavior, both compounds are discovered to be mechanically and thermodynamically stable in the cubic phase. Both compounds exhibit substantially enhanced conductivity and absorption in the low-energy range. While comparing NaScH₃ to KScH₃, the reflectivity and refractive index values for the former are significantly higher. Both the materials possess anisotropic and hard nature represented by anisotropic factor, young’s modulus, bulk modulus and mean shear modulus. Both compounds exhibit the brittle nature which is investigated with the help of poisson ratio and Pugh’s ratio. The values of bulk modulus, young’s modulus and mean shear modulus are higher for KScH₃ than NaScH₃ showing more hardness in KScH₃. The ratio of gravimetric hydrogen storage is found 3.48 and 4.27 wt %, for KScH₃ and NaScH₃, respectively which shows that both materials can accommodate a good amount of hydrogen, however, NaScH₃ can be preferred for hydrogen storage applications due to the higher storage capacity of hydrogen.

First-principles calculations combined with the Boltzmann transport theory were used to calculate the thermoelectric characteristics of Zr_1−xNiSnTa_x (x = 0, 1/4, 1/8, 1/12, 1/16, 1/24, 1/32, 1/36, 1/48, and 1/64). Ta-doped ZrNiSn can effectively improve the Seebeck coefficient of Zr_1−xNiSnTa_x, and it can also reduce its thermal conductivity. The maximum Seebeck coefficients of p-type and n-type Zr_3/4NiSnTa_1/4 are 1117.58 μV/K and − 1059.47 μV/K, respectively. The maximum thermoelectric figure of merit of the p-type Zr_3/4NiSnTa_1/4 thermoelectric material is 0.98, and the maximum thermoelectric figure of merit of the n-type Zr_3/4NiSnTa_1/4 thermoelectric material is 0.97. The optimum thermoelectric figure of merit of Zr_1−xNiSnTa_x studied in this paper is higher than those of other studies. Our results demonstrate the good potential thermoelectric material of Zr_1−xNiSnTa_x for thermoelectric device applications.

Density Functional Theory (DFT) is incorporated in this study to examine the thermodynamic, electronic, mechanical, and optical characteristics of antiperovskite compounds A₃BO (A = K, Rb and B = Au, Br). The purpose of the study is to demonstrate a comprehensive understanding of these materials and their potential applications across various fields emphasizing their stability and energetic profiles. The electronic properties, including band structures, and density of states are also analyzed to understand the electrical behavior of these materials, which enables predicting their conductive and semiconductor nature. The band gaps of K₃AuO, K₃BrO, Rb₃AuO, and Rb₃BrO are 0.72 eV, 0.80 eV, 0.15 eV, and 0.29 eV, respectively. The study also investigated the mechanical properties of the antiperovskite structures, including elastic constants, bulk modulus, and shear modulus to provide insights into their mechanical stability and durability. Their Pugh’s ratio (B/G) is below 1.75 and negative Cauchy pressure indicates these compounds are brittle. And machinability index B/C₄₄ > 1.5 implies excellent lubricating properties. This phenomenon extends the potential industrial application of materials with specific mechanical integrity to their structural components. Additionally, the study investigated the optical properties of the A₃BO antiperovskite compounds, including the dielectric function, loss function, reflectivity, conductivity, refractive index, and absorption spectra. These findings provide a comprehensive understanding of how these materials interact with light, which could be useful in the development of optoelectronic devices. Overall, this DFT study provides significant insights into the multifaceted properties of A₃BO antiperovskite compounds, laying the groundwork for further experimental exploration and facilitating the targeted design of materials with tailored properties for specific technological applications.

This paper first presents an application of the war strategy optimization (WSO) algorithm in pattern synthesis of antenna arrays and dimensions optimization of microstrip patch antenna. As a new type of evolutionary algorithm inspired by nature, the WSO algorithm has global optimization ability in solving complex problem including nonlinearity and nonconvexity; therefore, it will exhibit the potential advantages in the above two typical multivariate nonlinear problems. For solving pattern synthesis problem, the sidelobe reduction synthesis and null controlling of linear antenna arrays with different element are selected as numerical cases, and the WSO algorithm achieves the desired main beams width and null depth by optimizing the amplitude-only and the phase-only, respectively. For dimensions optimization of microstrip patch antenna, the WSO algorithm realizes the minimized reflection coefficient (S₁₁) of − 80 dB at 3.1G Hz by optimizing the width and length of rectangle patch antenna. Moreover, compared with the Grasshopper optimization algorithm, the gray wolf optimization algorithm, and the invasive weed optimization algorithm, the WSO algorithm shows higher computational accuracy and faster convergence speed for solving the above two types of optimization problem. Therefore, the WSO algorithm can be widely used to in electromagnetic structure design.

While the demand for electrical energy in the world increases daily, a large part of this demand is still provided by fossil fuels. However, the most significant contribution to solving the economic and environmental problems that arise is the spread of renewable energy production systems. Solar power generation systems are one of these renewable energy generation systems. In this study, cell and module parameters are modeled and estimated in different ways to obtain maximum energy from solar cells used in solar power generation systems. Cell and model vendors need to provide complete information to the end user. Therefore, the systems created turn into a nonlinear problem with many unknown parameters. In this study, single-diode model (SDM), double-diode model (DDM), and triple diode model (TDM) for photovoltaic (PV) cells as well as parameter estimations of four different PV modules produced by other vendors were performed for the first time with the dingo optimization algorithm (DOA). The mathematical model of PV module parameters is derived using open-circuit voltage (V_oc), short-circuit current (I_sc), and maximum power point values (P_mpp). The parameter values obtained by the algorithm aim to get the maximum power point curve for each model and module with minimum error. These values are compared with five traditional and five recent meta-heuristic algorithms, which have extreme positions in the literature.

In this paper, a strain-modified Si/Si_0.97C_0.03 asymmetrical superlattice exotic type (p + -i-p-n +) avalanche photodetector has been designed for applications on the infrared wavelength region. The photoelectric characteristics of the device are studied by developing a self-consistent quantum phenomena-based drift–diffusion model in conjunction with PSpice simulator. The overall performance of the device has been boosted significantly by introducing strain engineering which enhances the out-plane mobility of the charge particles in the intrinsic/active region of the device. The strain is produced in the intrinsic/active region by inclusion of small amount of carbon (C) into the pure Si material. The proposed strain-modified exotic avalanche photodetector exhibits better performance in terms of quantum efficiency (0.671) and photo-responsivity (0.645 A/W) compared to its planer unstrained Si counterpart (quantum efficiency: 0.481, photo-responsivity: 0.524A/W) at 1800 nm wavelength. Additionally, a 3 × 4 array of photodetectors has been designed using this device and its optoelectronic properties are studied in the IR wavelength region. The superiority of the performance of the 3 × 4 array of photodetectors is established in terms of better quantum efficiency (0.872) and better photo-responsivity (0.851 A/W). The validity of quantum phenomena-based drift–diffusion model is established by comparing the simulated data with experimental findings under similar operating conditions. The developed device can be used in defense as well as biomedical industries for sensing applications.