East European Journal of Physics

Advancements in Antiperovskite Structured Solids: A Comprehensive Review

2025-12-07T22:07:22+00:00

Antiperovskite-structured solids are attracting growing attention as a new class of multifunctional materials. Unlike conventional perovskites, their inverted cubic framework gives rise to unusual and highly tunable properties, from fast-ion conduction and giant magnetoresistance to superconductivity and negative thermal expansion. These different behaviors indicate promise for applications in areas such as solid-state batteries, energy-harvesting refrigeration, superconducting electronics, and thermal management. This review collates recent work in both experimental and theoretical research, emphasizing how a single simple cubic lattice can provide such a wide range of functionality. We argue that the structural versatility of antiperovskites is the common link between ionic transport, spin–lattice coupling, superconductivity, and thermal expansion. Recent advancements in Li- and Na-based solid electrolytes with high conductivity, giant magneto- and barocaloric responses, non-oxide superconductivity, and isotropic negative thermal expansion demonstrate that antiperovskites retain scientific importance and are increasingly viable competitors with the best of today’s functional materials.

Hubble’s Law and It’s Exponential Generalization with Cosmological Applications

2025-12-07T22:07:25+00:00

Hubble’s law reveals how the components of the universe adhere to overarching dynamical rules on a cosmological scale. While it is most renowned for describing the universe’s expansion, a general displacement equation derived in alignment with this law, along with a general equation of converging displacement, has been applied to estimate the time remaining before the Milky Way and Andromeda collide. This estimate closely aligns with results from numerical simulations of other studies. Additionally, the implications of this generalized equation provide valuable insights into key cosmological enigmas, including the time variation of the Hubble parameter, the cosmological past incompleteness, and the enduring mystery of the relationship between the subtle value of the cosmological constant and the quantum zero-point energy of the vacuum. It has also been successful in explaining the structure of spiral galaxie.

Cosmological Diagnostics and Stability of Dark Energy Model in Non-Metric Gravity

2025-12-07T22:07:27+00:00

In this study, we investigate the dynamics of generalized ghost pilgrim dark energy in the background of f(Q,C) gravity, where Q is the non-metricity scalar and C represents the boundary term. To complete this objective, we take an isotropic and homogeneous universe with an ideal matter distribution. Our analysis includes a scenario with non-interacting fluids, encompassing both dark matter and dark energy. To understand the cosmic dynamics, we reconstruct a f(Q,C) model and examine its influence on the universe evolution. We explore key cosmological factors, i.e., state variable, the behavior of (ωD - ω'D)-plane and the statefinder diagnostic pair, which help to analyze the cosmic expansion. A crucial aspect of our analysis is the stability of generalized ghost pilgrim dark energy model via the squared sound speed method, confirming its viability in supporting the observed accelerated expansion. Our findings are consistent with observational data, demonstrating that f(Q,C) gravity provides a robust theoretical foundation for describing dark energy and the universe large-scale dynamics. This work not only deep our understanding of modified gravity and mysterious energy but also offers new insights into alternative explanation for cosmic acceleration beyond standard paradigms.

Modified QCD Ghost Scalar Field Dark Energy in Anisotropic and Interacting Universe Models

2025-12-07T22:07:29+00:00

In this work, we study the Bianchi type-III interacting framework of modified QCD ghost dark energy with cold dark matter is being considered for illustrating the accelerated expansion of the Universe. The equation of state parameter shows evolution of the universe completely varies in quintessence region only. The dynamics of scalar field and corresponding potential of various scalar field models shows consistence behavior with the accelerated expansion phenomenon. Also, the kinetic energy term of k-essence models lies within the range where equation of state parameter represents the accelerated expansion of the Universe.

Predicting New Bc Mesons' Excited States: The Tridiagonal Matrix-Numerov Approach

2025-12-07T22:07:31+00:00

The properties of Bottom-charmed meson states were extensively investigated using Numerov's tridiagonal matrix approach to predicting the radial wavefunctions. Based on the resulted values, we predicted the β anharmonicity values and root mean square radii for different excited states of B_c mesons. A comprehensive comparison between the estimated results and recently published theoretical and experimental data was conducted, exhibiting a comparable product with a high degree of accuracy.

Squeezed Coherent States in Supersymmetric Quantum Mechanics with Position-Dependent Mass

2025-12-07T22:07:34+00:00

In this paper, we construct and analyze a class of squeezed coherent states within the framework of supersymmetric quantum mechanics (SUSYQM) involving a position-dependent mass (PDM). Using a deformed algebraic structure, we generalize the creation and annihilation operators to accommodate spatially varying mass profiles. The resulting states exhibit non-classical features, such as squeezing, coherence, and modified uncertainty relations, strongly influenced by both the deformation parameters and the mass function. We explore their physical properties through expectation values, variances, and probability densities. This work provides a pathway toward extending coherent state theory to more complex quantum systems with geometrical and algebraic richness.

Quantum-Corrected Thermodynamics of AdS-Rindler Black Holes

2025-12-07T22:07:36+00:00

We investigate the thermodynamic properties and stability of hyperbolic (AdS–Rindler) black holes, emphasizing the effects of non perturbative quantum correction. Using standard thermodynamic formulations alongside the Poincar´e disk method, we compute key quantities including mass, Hawking temperature, entropy, and heat capacity. To account for quantum gravitational effects, we introduce an exponential correction to the Bekenstein–Hawking entropy and systematically derive the modified thermodynamic parameters. While the corrected entropy yields consistent adjustments, the heat capacity exhibits nontrivial behavior, leading to narrower and more gradual stable regions (Δr_(d)) for each dimension d. Moreover, the smoothing of sharp entropy variations near r_h=1 emphasizes how horizon geometry governs the impact of quantum corrections. This study provides the novel systematic identification of stable regions before and after exponential corrections of (AdS–Rindler) black holes, offering new insights into the interplay of geometry, dimensionality, and quantum effects in black hole thermodynamics.

Spin Algebra and Naimark’s Extension: A Tutorial Approach with Examples

2025-12-07T22:07:39+00:00

In analyzing two-electron systems, the interactions of interest often include the spin-spin operator S^→₁×S^→₂) and the spin-orbit operator L^→·S^→. When these operators act on entangled or indistinguishable particles, their measurement and physical interpretation may extend beyond the standard projective framework. This tutorial introduces the algebraic structure of spin interactions in two electron quantum systems and establishes its conceptual and mathematical connection with \emph{Naimark's Extension Theorem}. Through explicit examples for two-electron systems, we demonstrate how spin operators arise in reduced Hilbert spaces, and how \emph{Naimark's theorem} provides a formal framework for extending these to projective measurements in enlarged spaces. The application of \emph{Naimark's Extension Theorem} in deriving their matrix elements opens up a window into the structure of quantum measurements in such composite systems.

Anisotropic Dark Energy Cosmology in the Framework of f (R, Lm) Gravity

2025-12-07T22:07:43+00:00

In this paper, we investigated the Locally Rotationally Symmetric (LRS) Bianchi Type-I cosmological model with dark energy in the framework of f (R, L_m) gravity theory, where R is the Ricci scalar and L_m is the matter Lagrangian. Using the functional form f (R, Lm) = R/2 + L^α_m + β with L_m = ρ, and applying the special law of variation for the Hubble parameter, we derived exact solutions to the field equations and analyzed the physical and dynamical properties of the universe. Our results show that the model exhibits accelerated expansion consistent with the observational data, with the energy density decreasing and the deceleration parameter transitioning from positive to negative values. The anisotropy parameter initially approaches zero but increases with time for n > 0.5, indicating the evolution from isotropy to anisotropy. These findings provide insights into dark energy behavior within modified gravity frameworks and offer testable predictions for cosmological observations.

Extension from Core to No-Core Nuclear Shell Model with Hartree–Fockwave Function: Application to Positive-Parity States in 19F

2025-12-07T22:07:46+00:00

This work presents a detailed investigation of low-lying positive-parity states in the ¹⁹F nucleus by combining shell-model techniques with Hartree–Fock (HF) calculations. The study systematically extends from traditional core-based spaces (sd, zbm, psd) to the fully untruncated no-core configuration (spsdp f). Realistic single-particle wavefunctions were generated using harmonic oscillator (HO), Woods–Saxon (WS), and Skyrme parameterizations. The approach was tested across a broad set of observables, including excitation spectra, electromagnetic form factors (C0, C2, C4, M1, M3, E2, E4, and E4+M5), transition probabilities, magnetic dipole and electric quadrupole moments, as well as binding energies and rms charge radii. Discrepancies reported in earlier theoretical work, particularly for the M1 and C4 transitions at higher momentum transfers, were resolved through expanded model spaces and refined radial wavefunctions. Together with our previous study of negative-parity states in ¹⁹F, these results provide a coherent picture: systematic core-to-no-core extensions are essential for accurately reproducing both detailed and bulk nuclear properties. This unified framework strengthens theoretical modeling of 19F and establishes a foundation for future shell-model studies of nuclei in transitional and deformed regions.

Secondary Neutron and Proton Production in Proton-Induced Reactions with ¹²C, ¹⁶N and ¹⁶O Nuclei

2025-12-07T22:07:49+00:00

The results of computer simulation of the secondary neutrons and protons yield per one incident proton during the interaction of protons with an energy of 50 MeV with light nuclei - ¹²C, ¹⁴N, and ¹⁶O using the TALYS - 1.96 code by default are presented. The importance of taking into account the radiation of secondary nucleons - neutrons and protons is a necessary element in conducting fundamental and applied nuclear research, such as dosimetry and radiation safety. As a result, the values of the total cross section for the secondary neutrons and protons production were obtained, that indicate significant differences in their energy range dependencies versus the target nucleus. For the nucleus ¹²C, the threshold for the production of neutrons is in the region of 20 MeV. A similar characteristic for ¹⁴N lies in the region of up to 10 MeV, and for ¹⁶O the total neutron production threshold is 17-18 MeV. The maximum neutron yield per incident proton is observed for the ¹⁶O nucleus. The total secondary proton production cross-section and their yield were also determined. In the case of proton yield, the oxygen nucleus demonstrates the largest number of secondary protons per proton, which is 1.47. The calculated values of the energy differential cross-section of the secondary radiation of protons and neutrons were also obtained. The maximum average energy of secondary protons is observed for the ¹⁴N nucleus and is 12.72 MeV, while for the ¹²C, and ¹⁶O nuclei it is about 10 MeV. Analysis of the energy differential cross-section of secondary neutrons showed that the maximum average energy is possessed by neutrons formed as a result of interaction with the nitrogen nucleus, while the energies of secondary neutrons formed on the nuclei of ¹²C, and ¹⁶O are approximately equal (6.2 and 6.4, respectively).

Quiescent Solitons in Magneto-Optic Waveguides with Nonlinear Chromatic Dispersion and Kudryashov’s Form of Self-Phase Modulation Having Generalized Temporal Evolution

2025-12-07T22:07:53+00:00

The article discusses how Kudryashov's proposed self-phase modulation scheme and nonlinear chromatic dispersion cause the evolution of quiescent optical solitons in magneto-optic waveguides. Provide a comprehensive understanding of the governing model; generalised temporal evolution is considered. The modified sub-ODE approach is employed to facilitate the recovery of such solitons. This leads to a complete range of optical solitons and the necessary conditions that must be met for these solitons to exist, which are also provided.

Partial Exact Solutions of Nonlinear Distribution One-Component Order Parameter in Equilibrium Systems

2025-12-07T22:07:55+00:00

This paper investigates partial exact solutions of a nonlinear fourth-order differential equation arising from the variational principle for a thermodynamic potential with high derivatives. To describe the spatial distribution of the order parameter, the elliptic cosine function of Jacobi is used, which allows reducing the problem to a system of algebraic equations for amplitude, spatial scale, and modulus. The conditions for the existence of physically admissible solutions were obtained, and it was found that periodic solutions expressed in terms of elliptic cosine are relevant for describing first-order phase transitions. Graphs illustrating the dependence of the main parameters of the solution on the characteristics of the system are presented.

On Solutions of the Killingbeck Potential and Clarifying Comments on a Related Analytical Approach

2025-12-07T22:07:57+00:00

The work presents analytical solutions to the Schrödinger equation for the Killingbeck potential, a hybrid model combining harmonic, linear, and Coulombic terms, as well as an approximate model of Yukawa-type potentials. The radial Schrödinger equation is solved by means of the series expansion method, thus yielding the exact expressions of both bound-state solutions and eigen-functions for systems such as quarkonium and confined hydrogen-like atoms in plasma environments. Furthermore, we offer a constructive commentary on the work of Obu et al. (East Eur. J. Phys. 3, 146–157, 2023), with the aim of clarifying a mathematical misstatement utilised in their analytical treatment of analogous systems.

On Synchronization of an Ensemble of Oscillators Under Superradiance Conditions

2025-12-07T22:07:59+00:00

The problems of phase synchronization in an ensemble of oscillators or dipoles, and the mechanisms of coherent field generation in superradiance mode, are discussed. It is shown that an increase in the spread of the initial amplitudes of an ensemble of oscillators suppresses their phase synchronization and reduces the efficiency of field generation. The influence of noise is discussed; it is shown that, below the generation threshold, even an external initiating field cannot synchronize the phases of an ensemble of particles. When the generation threshold is exceeded, the initiating field may not be required. It is shown that the convergence of the oscillator phases with the field phases at the locations of moving oscillators is noticeable only near their exit from the system. At the same time, a complete coincidence of the phases of synchronized oscillators and the field phases in the region of their localization is not observed. Nevertheless, the intensity of the generation field in the superradiance mode significantly exceeds the spontaneous level, which allows us to speak about the signs of induced radiation. The features of the development of the quantum process of superradiance of an ensemble of dipoles are discussed, and a system of equations for its description is given. The features of the quantum analog of superradiance are qualitatively modeled, and the role of the Rabi frequency determining the dynamics of the population inversion is noted. The nutation of the population inversion in the region occupied by the field affect the field intensity not only in this local zone, but also in subsequent regions of the active zone. This explains the unusual nature of the generation development: the field growth in a certain region of the active zone first stabilizes and then decreases significantly. This decrease in intensity also occurs in the direction of radiation in the peripheral regions of the active zone, despite the large energy reserve in them in the form of unperturbed population inversion.

Stimulated Raman Scattering of high power beam in quantum plasma: Effect of relativistic-ponderomotive Force

2025-12-07T22:08:01+00:00

The present work explores stimulated Raman scattering of a high-power beam in quantum plasma due to the joint action of relativistic ponderomotive force (RP force). The RP force creates nonlinearity in the plasma’s dielectric function. This results in a change in the density profile in a transverse direction to the axis of the pump beam. This change in density profile has a significant impact on all three waves involved in the process, viz., the input beam, the electron plasma beam, and the scattered wave. Second-order ODEs for all three waves, as well as the SRS back-reflectivity expression, are set up and further solved numerically. Impact of well-known laser-plasma parameters, quantum contribution, and combined action of RP force on beam waists of various waves, and also on SRS back-reflectivity are explored.

Emergence of Large-Scale Magnetic-Vortices Structures by Small-Scale Helicity in Stratified Magnetized Plasma

2025-12-07T22:08:04+00:00

In this paper, a new type of instability is identified, leading to the generation of vortex motions and magnetic fields in a plasma layer with a constant temperature gradient, subjected to uniform gravity and a vertical magnetic field. The analysis in this study is conducted within the framework of electron magnetohydrodynamics (EMHD), taking into account thermomagnetic effects. A new large-scale instability of the α-effect type is identified, which facilitates the generation of large-scale vortex and magnetic fields. This instability arises due to the combined action of an external uniform magnetic field, oriented perpendicular to the plasma layer, and a small-scale helical force. The external force is modeled as a source of small-scale oscillations in the electron velocity field, characterized by a low Reynolds number (R<<1). The presence of a small parameter in the system allows for the application of the method of multiscale asymptotic expansions, leading to the derivation of nonlinear equations governing the evolution of large-scale vortex and magnetic perturbations. These equations are obtained at third order in the Reynolds number. A new effect associated with the influence of thermal forces (the Nernst effect) on large-scale instability is also discussed. It is shown that an increase in the Nernst parameter reduces the α-coefficient and thereby suppresses the development of the large-scale instability. Using numerical analysis, stationary solutions of the vortex and magnetic dynamo equations are obtained in the form of localized helical-type structures.

Solitary Wave and Shock Wave Perturbation for the Modified Kawahara Equation

2025-12-07T22:08:08+00:00

This paper retrieves shock waves and solitary wave solutions to the modified Kawahara equation in the presence of perturbation terms. The generalized G'/G-expansion approach is the adopted integration methodology for the model. The parameter constraints naturally emerge during the course of derivation of the solutions which guarantee the existence of such waves.

Stimulated Raman Scattering of High-Power Beam in Collisional Magnetoplasma

2025-12-07T22:08:11+00:00

The present problem investigates Stimulated Raman Scattering of high-power beam in Collisional magnetoplasma. The laser beam has two propagation modes viz. extraordinary and ordinary modes, while its transition along the direction of static magnetic fields. The carrier redistribution affected due to modification in static magnetic field. The carrier redistribution will take place due to non-uniform heating, which results in variation in density profile in a transverse direction to axis of main beam. This density profile further causes modification in all the three waves involved in the process viz. incident beam, electron plasma wave and scattered wave. Here, 2^nd order ODE for beam waists of pump beam, EPW and back-scattered wave and also expression for reflectivity will be obtained and further their numerical simulations will be carried out in order to explore impact of change in laser and plasma parameters and also externally applied magnetic field on beam waists of various waves and on SRS back-reflectivity.

Effect of Ion Temperature on the Dynamics of Analytical Solitary Wave Solution of the Dust Ion Acoustic Waves for the Damped Forced KdV Equation in q−nonextensive Plasmas

2025-12-07T22:08:15+00:00

This paper examines the dynamical properties of the analytical solitary wave solution of dust ion acoustic (DIA) solitary waves induced by the damped forced Korteweg-de Vries (DFKdV) equation in an unmagnetized collisional dusty plasma that contains neutral particles, q-nonextensive electrons, positively charged ions, and negatively charged dust grains in the presence of an external periodic force. To obtain the damped forced
Korteweg-de Vries (DFKdV) equation, the reductive perturbation approach was developed. It is observed that both the compressive and rarefactive dust-ion acoustic (DIA) solitary-wave solutions are possible for this plasma model. The effects of a number of physical parameters are taken into account: the entropic index (q), dust ion collisional frequency (ν_id0), traveling wave speed (M), periodic force frequency (ω), ion-to-electron
temperature ratio (σ), the parameter that is the ratio between the unperturbed densities of the dust ions and electrons (μ), the strength and frequency of the external periodic force (f₀). It is observed that those parameters have significant effects on the structures of the damped forced dust-ion acoustic solitary waves. The implication of the outcomes of this investigation may be relevant for understanding the dynamics of dust-ionacoustic (DIA) solitary waves in laboratory plasma as well as in space plasma environment.

Third Harmonic Generation of q-Gaussian Laser Beam in Collisionless Plasma

2025-12-07T22:08:17+00:00

The current study investigates third harmonic generation (THG) of a q-Gaussian beam propagating through collisionless plasma. The density gradients get induced in plasma due to nonlinear ponderomotive force. They excite electron plasma wave (EPW) at twice pump frequency via V^->xB^-> mechanism. EPWs and pump wave couples with each other producing third harmonics. The nonlinear ODE for beam waist of pump beam and THG conversion efficiency expressions are obtained by employing WKB and paraxial approaches. The influence of key laser-plasma parameters on self-focusing of main beam and 3^rd harmonic efficiency is also analyzed.

Implicit Quiescent Optical Soliton Perturbation Having Nonlinear Chromatic Dispersion and Linear Temporal Evolution with Kudryashov’s Forms of Self–Phase Modulation Structure by Lie Symmetry

2025-12-07T22:08:20+00:00

The paper retrieves implicit quiescent optical solitons for the nonlinear Schr¨odinger’s equation that is taken up with nonlinear chromatic dispersion and linear temporal evolution. Using a stationary or quiescent approach combined with Lie symmetry analysis, the study systematically examines six distinct self–phase–modulation structures proposed by Kudryashov. The analytical procedure reduces the governing equation to amplitude forms whose solutions are obtained through quadratures, leading to both implicit solitary–wave profiles and one explicit periodic case. The six forms of self–phase modulation structures, as proposed by Kudryashov, yielded solutions in terms of quadratures, periodic solutions as well as in terms of elliptic functions. The existence of each family of solutions is discussed in terms of the admissible parameter relations that ensure physically meaningful solitary profiles. The approach provides a unified framework compared with earlier methods based on direct elliptic–function expansions, highlighting how Lie symmetry facilitates a compact treatment of multiple nonlinear dispersion laws. The results are relevant to understanding stationary optical pulses in nonlinear fibers and photonic crystal fibers, and they establish a foundation for future numerical and experimental studies on nonlinear–dispersion–driven pulse propagation.

Effect of Anisotropic Dust Pressure on the Formation and Propagation of Arbitrary Amplitude Dust Acoustic Solitary Waves (DASW) in a Magnetized Dust-Ion-Electron Plasma

2025-12-07T22:08:23+00:00

Arbitrary amplitude dust acoustic solitary waves (DASW) in a dusty magneto-plasma with anisotropic dust pressure and nonthermal distribution of ions and electrons has been investigated. Sagdeev pseudopotential technique is used to derive an energy balance equation and to analyze various properties of dust acoustic solitons. The effects of anisotropic dust pressure, dust number density ratio, non-thermality, etc., are investigated numerically for the propagation of DASWs. It is found that rarefactive solitons can exist for negatively charged dust, and compressive solitons can exist for positively charged dust. The present study could be useful for the understanding of DASWs in various astrophysical environments.

Propagation of an Azimuthally Polarized Terahertz Laser Beams with a Phase Singularity

2025-12-07T22:08:25+00:00

Analytical expressions are derived to describe the nonparaxial diffraction of modes in a dielectric waveguide resonator for a terahertz laser. The study examines the interaction between azimuthally polarized TE_0m (m = 1, 2, 3) modes and a spiral phase plate (SPP), accounting for its different topological charges (n). Using numerical modeling, the emerging physical properties of vortex beams are investigated when they propagate in free space. Vector integral Rayleigh-Sommerfeld transforms are used to study the propagation in the Fresnel zone of vortex laser beams excited by TE_0m modes of a dielectric waveguide quasi-optical resonator when they are incident on a phase plate. In the studied modes, in the absence of a phase plate, the field exhibits a ring-shaped transverse intensity distribution along the propagation axis. In this case, the number of rings in the cross-section corresponds to the azimuthal number of modes, and the phase distributions for the transverse components of these modes have opposite signs. The use of a SPP with a topological charge n = 1 changes the structure of the beam field, forming an axial maximum in the transverse profile with an increase in the beam diameter at this maximum compared to the case without a phase plate. At the same time the phase structure of the field for transverse components acquires two-lobe symmetry. When using a SPP with a topological charge n = 2 for the TE₀₁ mode the restoration of the ring-like field structure is observed and for the TE₀₂ and TE₀₃ modes the formation of regions of increased intensity is observed. In this case, the phase distributions of the field components for the TE₀₁ and TE₀₂ modes acquire a three-lobe spiral structure, whereas those for the TE₀₃ mode acquire a multi-lobe spiral configuration.

Pushing Efficiency Limits: SCAPS-Based Analysis of GaAs and BAs Solar Cells for Next-Generation Photovoltaics

2025-12-07T22:08:29+00:00

The present study utilizes SCAPS software to simulate and analyze the semiconductor materials gallium arsenide (GaAs) and boron arsenide (BAs) for photovoltaic applications. We outline the methodology, emphasizing critical factors considered during simulation. The performance of solar cells is investigated through quantum efficiency and photovoltaic performance curves. Additionally, the observed trends, key differences between GaAs and BAs, and their implications for advancing high-efficiency solar cells are discussed.

Numerical Investigation of Lead-Free Perovskite Solar Cells Based on FASnI₃/ZrS₂ Structure Using SCAPS-1D Simulator

2025-12-07T22:08:31+00:00

This study presents a numerical investigation and optimization of lead-free perovskite solar cells using SCAPS-1D simulation. The proposed device is composed of formamidinium tin iodide (FASnI₃, absorptive layer), zirconium disulfide (ZrS₂, electron transport material), gold (Au, the back contact), and Fluorine-doped tin oxide (SnO₂:F, the front contact).The effects of varying the thickness, defect density, doping concentration, operating temperature, and back-contact work function on the photovoltaic performance were studied to determine the optimal device architecture with the highest power conversion efficiency (PCE). Results reveal that the initial performance of FASnI₃/ZrS₂ solar cells was as follows: open-circuit voltage (V_OC) =0.99V, short-circuit current (J_SC) = 20.7mA/cm², Fill factor (FF) = 60.13%, and power conversion efficiency (PCE)=12.4%.After optimization, the performance of FASnI₃/ZrS₂ significantly improved, achieving a PCE of 23.3%, FF of 82.4%, and J_SCof 30.2mA/cm².This remarkable improvement in these parameters is attributed to the increase in thickness and doping density of the FASnI₃ and ZrS₂ layers which lead to improved light absorption and charge generation. Additionally, the 5.3 eV work-function of the back contact was found to create a better energy level alignment with the FASnI₃ layer, which facilitates charge extraction. These findings offer valuable insights into the design of efficient, stable, and lead-free perovskite solar cells.

Enhancing and Optimizing Optical Properties of Bifacial Solar Cells by Incorporating Metal Nanoparticles

2025-12-07T22:08:33+00:00

In this study, the optical properties of a silicon-based bifacial solar cell with an n⁺–p–p⁺ structure were investigated using numerical simulation in the Sentaurus TCAD environment. Various metal nanoparticles were embedded in the emitter layer in a linear configuration to analyze their effects on light absorption and scattering. The study compared metal nanoparticles of platinum (Pt), gold (Au), silver (Ag), aluminum (Al), and copper (Cu). All nanoparticles were modeled with the same diameter (5 nm), and the current-voltage (I–V) characteristics were obtained for each configuration. The simulation results showed that platinum nanoparticles yielded the highest short-circuit current density of 13.8 mA/cm², while silver nanoparticles yielded the lowest, at 5.027 mA/cm². Optimal parameters were observed with nanoparticles of 5 nm in diameter. Furthermore, it was found that the photon absorption density for the most efficient metal type was 1.81 times greater than that of the reference structure without nanoparticles. Additionally, the spectral sensitivity of silicon shifted toward the ultraviolet region in the presence of metal nanoparticles. The study demonstrated enhanced utilization of the visible light spectrum, and due to the embedded nanoparticles, the overall absorption coefficient of the bifacial solar cell increased by a factor of 1.33, aligning more effectively with the visible spectral range.

Energy Transport in a MHD Hybrid Nanofluid Flow Over a Porous Exponentially Stretching Sheet

2025-12-07T22:08:36+00:00

This study presents an in-depth analysis of heat transfer mechanisms and fluid flow behavior associated with hybrid nanofluids in the presence of an exponentially stretching surface. Hybrid nanofluids, formed by dispersing more than one type of nanoparticle within a base fluid, exhibit superior thermophysical properties compared to conventional nanofluids. Their enhanced thermal conductivity, modified density, and tailored specific heat capacity make them highly suitable for advanced applications in nanotechnology, renewable energy systems, high-performance electronics cooling, and industrial-scale heat exchangers. The novelty of the present research lies in its attempt to explore the combined impact of hybrid nanoparticles and exponential stretching on boundary layer dynamics, thereby offering new insights into optimizing thermal systems. The core aim of this investigation is to maximize heat transfer efficiency under varying physical and operational conditions. To achieve this, the governing partial differential equations describing the conservation of mass, momentum, and energy are transformed into a set of nonlinear ordinary differential equations using similarity transformations and appropriate dimensionless parameters. This mathematical reformulation simplifies the complexity of the problem while preserving the essential physics of the flow. A computational framework is developed in MATLAB, where the coupled system of equations is solved using the fourth-order Runge–Kutta method integrated with a shooting technique to ensure accuracy and stability. The analysis highlights the roles of key parameters such as magnetic field intensity, Eckert number (viscous dissipation effects), Prandtl number (thermal diffusivity effects), and thermal radiation on velocity profiles, temperature distributions, and porous medium behavior. The results not only reveal the sensitivity of the flow and thermal fields to these controlling factors but also identify regimes where hybrid nanofluids significantly outperform traditional working fluids.

Three-Dimensional MHD Flow and Heat Transfer of Water-Based Nanofluids over a Stretching Surface with Coriolis Force and Thermal Effects

2025-12-07T22:08:39+00:00

This study focuses on the thermal behavior and three-dimensional boundary layer flow of water-based nanofluids over a stretched surface, considering the combined effects of Coriolis and Lorentz forces. The model includes several important physical aspects such as surface convection, internal heat generation, Joule heating, viscous dissipation, and thermal radiation. Copper (Cu), aluminum oxide (Al₂O₃), and magnetite (Fe₃O₄) nanoparticles are dispersed in water to compare their effectiveness in enhancing heat transfer. By applying similarity transformations, the complex system of partial differential equations is reduced to a set of nonlinear ordinary differential equations, which are then solved numerically using the Runge-Kutta-Fehlberg method along with the shooting technique. The results show that nanofluids containing Cu nanoparticles provide the highest thermal performance, followed by those with Al₂O₃ and Fe₃O₄. These findings highlight the importance of selecting appropriate nanoparticles to improve heat transfer efficiency in thermal management applications. Increasing rotation parameter λ suppresses the axial velocity while simultaneously reducing the temperature distribution, highlighting the damping influence of rotational effects on momentum and heat transport.

Magnetohydrodynamic Casson Hybrid Nanofluid Dynamics in Circulating Blood Considering Thermal Radiation and Chemical Reaction

2025-12-07T22:08:41+00:00

The purpose of this work is to investigate the relevance of thermal radiation and chemical reaction in the thermal and radiative analysis of hybrid Casson nanofluid dynamics. The physical model was based on the mixture of Gold and Silver hybrid nanoparticles (HN) which are suspended in a blood past a stretchable sheet. The dynamics of fluid past a stretchable sheet is a notable analysis for thermal and momentum boundary layers. It finds applications in various technological fields and in industries. The model equations were investigated using a system of partial differential equations (PDEs). Acceptable transformation was used to convert these PDEs into total differential equations (ODEs). Later, the system of equations was solved using the Runge-Kutta algorithm along with shooting. The analysis described in this paper explained that hybrid nanoparticles have high performance in radiative and thermal processes when compared with nanofluid. The fluid's velocity was observed to be repelled by an increasing magnetic value because of the Lorentz force. A comparison with previous work showed close agreement.

Peristaltic Bile Flow in Papilla Ampoule of Porous Walls and Inclined Eccentric Catheterized Duct

2025-12-07T22:08:43+00:00

In this study, the combined effects of inclination and catheter on the biliary flow of a Carreau fluid through an eccentric catheterized duct with a porous material are mathematically investigated. The perturbation technique is employed to solve the governing equations, considering low Reynolds numbers, a long-wavelength approximation, and suitable small parameters. The surgical technique, when a catheter is inserted eccentrically into the duct, is connected to the outcomes of the investigation. Several parameters have been used to achieve the analytical solutions. Axial velocity, pressure gradient, flow rate, and wall shear stress are displayed in these data, together with the following emergent parameters: wall slip parameter, Weissenberg number, fluid behavior index, Darcy number, and angle of inclination. The pressure gradient is significantly altered by the angle of inclination and porosity parameter, and the catheter's axial velocity falls as the Weissenberg number rises. The physiological observations are consistent with these findings.

Soret and Dufour Effects on Ag –TiO₂ /Water in a Casson Hybrid Nanofluid Over a Moving Vertical Plate with Convective Boundary Conditions

2025-12-07T22:08:45+00:00

This research presents a comprehensive investigation of the Soret and Dufour effects on Casson hybrid nanofluid (HNF) flow past a moving vertical plate, with silver (Ag) and titanium dioxide (TiO₂) nanoparticles dispersed in water. The incorporation of Ag–TiO₂ hybrid nanoparticles combines the exceptional thermal conductivity of silver with the chemical stability and cost-effectiveness of TiO₂, creating a fluid with superior transport properties compared to conventional single-component nanofluids. The governing partial differential equations describing momentum, heat and mass transfer are transformed into a set of nonlinear ordinary differential equations using similarity transformations. These equations are solved numerically via the Keller Box method, ensuring stability and accuracy in handling coupled highly nonlinear systems. In addition, an analysis was performed to examine the influence of nanoparticle morphology on velocity, temperature and concentration distributions, thereby validating and enriching the numerical outcomes. The results reveal that variable nanoparticle morphology and the combined Ag–TiO₂ dispersion significantly enhance heat transfer rates and mass transfer rates while reducing frictional losses near the plate surface. The inclusion of Soret and Dufour effects further amplifies cross-coupling between thermal and solutal fields leading to improved transport efficiency. These findings not only provide new insights into Casson hybrid nanofluid dynamics but also highlight the critical role of cross-diffusion in optimizing heat and mass transfer systems. The integration of Casson fluid rheology, hybrid nanoparticles and cross-diffusion effects under realistic boundary conditions has direct implications for industrial cooling, metallurgical processing, biomedical drug delivery and energy system optimization. By demonstrating the synergistic performance of Ag–TiO₂ nanofluids, this study establishes a pathway for designing next-generation thermal management and biomedical transport technologies.

Impact of Magnetic Field on Peristaltic Transport of Nano-Coupled Stress Fluid in an Inclined Porous Tube

2025-12-07T22:08:47+00:00

This study provides a theoretical investigation of peristaltic transport of couple-stress nanofluid under the influence of a magnetic field in an inclined porous tube. With low Reynolds number, long wavelength approximations, appropriate analytical methods are employed to investigate the fluid’s velocity, frictional force, time-averaged flux, nanoparticle phenomena, pressure drop, and temperature profile. The effects of various physical parameters, including the thermophoresis parameter, Brownian motion parameter, local nanoparticle Grashof number, and local temperature Grashof number, on frictional force and pressure drop characteristics are investigated. Graphs are used to illustrate expressions for pressure drop, velocity, nanoparticle phenomena, temperature profile, and frictional force.

Photoluminescence and Magnetic Enhancement in ZnSe Quantum Dots Via Controlled Cobalt Doping

2025-12-07T22:08:49+00:00

Co²⁺ ion-doped ZnSe semiconductor quantum dots (QDs) were synthesized in aqueous solution using starch as a surface stabilizer to ensure nanoparticle dispersion. Structural and compositional analyses using X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) confirmed the successful incorporation of Co²⁺ ions into the ZnSe matrix. XRD and UV-visible absorption spectroscopy were used to determine the crystalline structure, lattice parameters, and particle sizes of Co-doped ZnSe QDs. The optical properties were analyzed using absorption and fluorescence spectroscopy, revealing a blue shift in the absorption peak with increasing Co concentration due to quantum confinement effects and changes in particle size. Photoluminescence (PL) analysis revealed dual emission peaks, corresponding to band-to-band recombination and Co-related defect states, with maximum luminescence efficiency observed at the 9% Co doping level. Beyond this concentration, the quenching effects attributed to the Co-Co interactions reduced the fluorescence intensity. Magnetic hysteresis measurements demonstrated that the Co-doped ZnSe QDs exhibited room-temperature ferromagnetism, with saturation magnetization increasing with co-doping concentrations of up to 12%. The ferromagnetic properties were ascribed to the exchange interactions between the Co²⁺ ions and the ZnSe matrix.

Synthesis of CdTe Quantum Dots Via the Molecular Precursor Method and Investigation of Their Optical Properties

2025-12-07T22:08:52+00:00

Cadmium telluride (CdTe) quantum dots (QDs) were synthesizedwere synthesized via a molecular precursor (hot-injection) method and their optical properties were investigated. A cadmium oleate precursor in octadecene/oleic acid was heated to 180 °C under an inert atmosphere, and a trioctylphosphine–tellurium (TOP-Te) solution was swiftly injected to initiate nucleation. By varying the growth time, the QD size was tuned, giving emission colors from green to red. The nanocrystals were characterized by UV–visible absorption and photoluminescence (PL) spectroscopy, which revealed a clear red shift in the optical spectra with increasing particle size. The QDs exhibited size-dependent optical properties consistent with quantum confinement, with the first excitonic absorption peak shifting from approximately 520 nm to 700 nm as the diameter increased. All samples showed high luminescence, with photoluminescence quantum yield (PLQY) values ranging from 60% to 90%. This colloidal synthesis at relatively low temperatures produced colloidally stable QDs with tunable band gaps. These results demonstrate a straightforward route to tailor QD optical properties by controlling the reaction time and provide insights into the growth kinetics and defect states in CdTe QDs.and provide insights into the growth kinetics and defect states in CdTe QDs.

Effect of Nickel Diffusion on Trap States and Interface Quality in Polycrystalline Silicon Structures

2025-12-07T22:08:54+00:00

This work presents a comprehensive Deep-Level Transient Spectroscopy (DLTS) investigation into the influence of nickel (Ni) diffusion on the defect landscape and electronic properties of polycrystalline silicon (poly-Si) structures. The study aims to clarify how Ni incorporation modifies electrically active traps, alters charge carrier dynamics, and affects interface quality in Schottky diodes formed on poly-Si substrates. Two types of samples—undoped and Ni-diffused—were prepared via controlled thermal processing at 1000 °C, followed by surface passivation and gold/aluminum metallization to form Au/Poly-Si/Al Schottky diodes. DLTS measurements over the temperature range 20–300 K revealed distinct differences in the deep-level trap behavior of the two sample types. In undoped samples, only weak and broad trap signals were observed, primarily associated with intrinsic grain boundary defects and residual impurities. In contrast, Ni-diffused samples exhibited sharp, intense DLTS peaks, with a dominant trap level observed between 200 and 220 K. The corresponding activation energy was estimated to be approximately 0.492 eV, and the capture cross-section was in the range of 10⁻¹⁴–10⁻¹³ cm². These parameters indicate the formation of nickel-related complex defects, such as Ni–V or Ni–O clusters, primarily located at grain boundaries. C–V profiling further confirmed the influence of Ni incorporation, showing reduced capacitance, a smoother transition in the depletion region, and improved interface uniformity, suggesting partial passivation of native and boundary-related traps. The Ni-diffused sample displayed a smoother capacitance–voltage transition, reduced junction capacitance, and improved interface uniformity, suggesting partial passivation of native defects. Complementary Gp–V measurements showed a significant decrease in parallel conductance for Ni-doped structures, indicating a reduction in interface trap density and recombination centers. These results suggest a dual role of nickel—both as a source of deep-level traps and as a passivating agent, depending on local atomic environment and thermal treatment conditions. Surface morphology analysis using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDX) confirmed the formation of Ni-rich precipitates, particularly at grain boundaries. The spatial correlation between Ni and oxygen suggests the formation of Ni–O-based complexes, which likely contribute to the electrical passivation effects observed in DLTS and G_p–V data. Overall, this study demonstrates that controlled Ni diffusion offers a promising approach for defect engineering in polycrystalline semiconductors. By selectively introducing and passivating defect states, Ni doping can enhance the electronic quality and thermal stability of poly-Si, thereby improving its suitability for high-efficiency solar cells, radiation detectors, and other advanced electronic and optoelectronic devices.

Morphology and Electrical Properties of ITO Films Obtained on Silicon Substrates by CVD Method

2025-12-07T22:08:59+00:00

ITO films were obtained on silicon substrates using an improved chemical vapor deposition (CVD) method in a quasi-enclosed volume at normal atmospheric pressure, without using a carrier gas. The resulting films had a thickness of 2.8–3.0 microns and a fairly low sheet resistance. Using an SPM 9700HT type scanning probe microscope, the surfaces of 500×500 nm ITO film samples were examined, and the results are presented in the form of two-dimensional (2D) and three-dimensional (3D) images. The electrophysical properties of the grown films were studied by the Hall method and it was shown that the films have an n-type conductivity, a mobility of m ≈ 2.5 cm²/(V×s) and a concentration of charge carriers n ≈ 1.35×10²⁰ cm^-3 and a sheet resistance of r ≈ 1.85×10^-5 W×sq^-1 (ohms per square). It is shown that our modified method of chemical vapor deposition makes it possible to obtain ITO films with good characteristics acceptable for use in optoelectronics and photovoltaics devices as a transparent contact layer.

Physical Principles of Photocurrent Generation in a Silicon-Based Photodiode Structure with a Schottky Barrier

2025-12-07T22:09:01+00:00

Homojunction structures of the type Ag–nSi–n⁺Si–(In+Sn) with perfect single-crystal (111) orientation and a high-resistivity compensated layer at the n⁺Si/n-Si interface were obtained using the liquid-phase epitaxy method. The results of investigating photogeneration processes and current transport mechanisms in the silicon Schottky-barrier photodiode structure are presented. A two-barrier model of the structure was developed, according to which current transport has a multifactorial nature and is governed by the combined contributions of thermionic emission, tunneling, and generation–recombination processes. Furthermore, it was established that the photosensitivity of the studied structure covers a photon energy range of 0.387÷1.016 eV, shifted toward the long-wavelength region. The formation of a near-surface high-resistivity layer contributes to an increased response and enables photosensitivity values of up to 0.338 A/W. It was found that reducing the barrier capacitance to 8÷10 pF broadens the frequency range and enhances the speed of response. The Ag–nSi–n⁺Si–(In+Sn) structures are promising for use in photodiodes of optoelectronic devices operating in the visible and infrared spectral regions.

Modification of the Kinetic Parameters of SnSe by Terbium Doping

2025-12-07T22:09:03+00:00

The kinetic parameters of solid solutions Tb_xSn_1-xSe (0 ≤ x ≤ 0.05), grown by the Bridgman method were investigated at 300 K. It was found that doping with Tb significantly affects the electrical conductivity, Hall coefficient, Seebeck coefficient (thermoelectric power), thermal conductivity, and the concentration and mobility of charge carriers. At low Tb concentrations, a transition from p-type to n-type conductivity is observed, accompanied by a non-monotonic change in the Hall coefficient and the sign of the Seebeck coefficient. Electrical and thermal conductivities decrease due to enhanced scattering at defects caused by introducing Tb. The obtained data are important for controlling the properties of SnSe in its thermoelectric applications.

Memristive Switching Behavior of Sol–Gel Derived Ga₂O₃ Thin Films

2025-12-07T22:09:05+00:00

Gallium oxide (Ga₂O₃) is an ultrawide bandgap semiconductor (~4.8–5.0 eV) that has recently gained considerable attention for next-generation nanoelectronic and memory devices owing to its superior breakdown field, chemical durability, and thermal robustness. In this study, Ga₂O₃ thin films were fabricated through a sol–gel spin-coating route and subsequently annealed at 1000 °C. X-ray diffraction revealed the structural evolution from an amorphous state to the stable monoclinic β-Ga₂O₃ phase after annealing. Electrical measurements exhibited reproducible bipolar resistive switching with an ON/OFF resistance ratio exceeding 10² and relatively low set/reset voltages. The observed switching is interpreted within the framework of conductive filament formation and rupture, predominantly governed by oxygen vacancy dynamics. The combination of low-cost synthesis, scalable processing, and robust memristive performance highlights sol–gel derived Ga₂O₃ thin films as strong contenders for future resistive random-access memory (RRAM) architectures and neuromorphic computing technologies.

Investigation of the Optical Properties of Metal Ion-Intercalated GaSe Semiconductor Monocrystals

2025-12-07T22:09:08+00:00

In this study, the XRD method was used to characterise the structural and phase properties of GaSe monocrystals, and the impact of Cu ion intercalation on their optical properties was investigated. An increase in absorption (ABS) was observed in the 200–400 nm region as a result of the addition of Cu ions, and new optical transitions occurred around 600 nm. Overall, observable variations in absorption levels have been observed over the 200–800 nm spectral range. Tauc analysis revealed that the band gap narrowed from approximately 2 eV to about 1.88 eV upon intercalation and slightly widened to about 2.15 eV with photo-intercalation. These results suggest that Cu ion intercalation can be applied to modify the optical properties of GaSe monocrystals, increasing their potential for use in nonlinear optical devices, photonics, and sensor technologies. The findings also demonstrate that intercalation is an appropriate technique for regulating the physical characteristics of layered materials.

Advanced First-Principle Study of AgGaTe₂ and AgInTe₂ Chalcopyrite Semiconductors: Structural, Electronic, and Optical Properties via FPLAPW within WIEN2K

2025-12-07T22:09:10+00:00

In this paper, we present a detailed theoretical exploration of the ternary chalcopyrite semiconductors AgGaTe₂ and AgInTe₂ using first-principles calculations grounded in Density Functional Theory (DFT). The simulations are carried out within the Full-Potential Linearized Augmented Plane Wave (FPLAPW) formalism as implemented in the WIEN2k computational package. Structural properties are optimized using the WC-GGA exchange–correlation functional, whereas the electronic and optical responses are refined through the modified Becke–Johnson (mBJ) potential, known for its improved bandgap estimation accuracy. The study involves a thorough evaluation of the electronic band structures and various optical parameters, including the complex dielectric function, absorption coefficient, refractive index, energy-loss function, and reflectivity. The findings reveal that both materials possess direct bandgaps that lie within the optimal range for solar cell absorption. Additionally, these compounds show strong light absorption in the visible and near-infrared regions, high refractive indices, and marked interband transitions. Such features highlight their suitability for photovoltaic technologies, especially in thin-film configurations where enhanced light capture and carrier generation are critical. Moreover, the observed optical and electronic properties also suggest possible utilization in infrared detection and nonlinear optoelectronic systems. Overall, the results contribute valuable theoretical insight into the optoelectronic characteristics of silver-based telluride chalcopyrites, reinforcing their potential as environmentally friendly and efficient materials for future solar energy solutions.

Electrophysical Characterization of Photodetectors Based on Semiconductor Structures Si (Li) and Si(Au)

2025-12-07T22:09:15+00:00

This paper explores the technological and physical principles for developing silicon-lithium (Si(Li)) nuclear radiation detectors with a thickness greater than 1.5 mm and a surface area of at least The formation of large-area p–i–n structures through lithium ion drift and diffusion mechanisms was analyzed. To evaluate the electrophysical parameters of the detectors, current-voltage (I–V) and capacitance-voltage (C–V) characteristics were measured. The I–V results under reverse bias in the range of showed extremely low leakage currents indicating the formation of high-quality junctions. Beyond 100 V, the current remained nearly constant, forming a plateau region. The findings propose effective technological solutions for the development of highly sensitive, stable, and low-noise radiation detectors.

Bandgap-Engineered pSi/n-CdₓS₁₋ₓ Heterojunctions: Effect of Composition on Optoelectronic Behavior

2025-12-07T22:09:18+00:00

This study provides a comprehensive analysis of the electrophysical properties of the pSi/n-CdₓS₁₋ₓ heterojunction, where the cadmium composition x varies continuously from 0 to 1. The investigation integrates theoretical modeling, numerical simulations, and experimental validation employing typical doping concentrations of p = 2 × 10¹⁷ cm⁻³ for p-type porous silicon and n = 1 × 10¹⁸ cm⁻³ for n-type CdₓS₁₋ₓ. Particular attention is devoted to the temperature-dependent evolution of key material parameters, including the bandgap energy Eg(T), intrinsic carrier concentration nᵢ(T), and the Debye temperature Θ(x). As the cadmium fraction increases, the bandgap narrowing in CdₓS₁₋ₓ becomes evident, while porous silicon maintains a relatively wide and thermally stable Eg(T), resulting in a substantial band offset (ΔEg) that enhances charge carrier separation across the interface. Furthermore, the reduction of Θ(x) with increasing cadmium concentration modulates phonon scattering and recombination dynamics, thereby influencing charge transport characteristics. The analysis of current transport mechanisms indicates that the junction behavior is predominantly controlled by temperature- and composition-dependent band alignment and carrier recombination processes. The obtained results validate the proposed physical model and demonstrate the promising potential of pSi/n-CdₓS₁₋ₓ heterostructures for high-temperature and acoustically tunable optoelectronic devices.

Effect of Substrate Temperature on the Morphology and Crystallinity of TiO₂ Thin Films Grown by ALD Using TTIP and H₂O

2025-12-07T22:09:20+00:00

This study investigates the influence of substrate temperature on the morphological and structural characteristics of TiO₂ thin films synthesized by thermal ALD using titanium tetraisopropoxide and water as precursors. The substrate temperature was varied from 200 to 275 °C in 25 °C increments. Surface morphology was examined using atomic force microscopy, while the crystalline structure was analyzed by XRD and Raman spectroscopy. It was found that films deposited at 200 °C exhibited an amorphous structure and a smooth, conformal surface with minimal roughness. Increasing the temperature to 225 °C led to the formation of microstructures and the emergence of initial signs of crystallization, accompanied by an increase in surface roughness. At 250-275 °C, a well-defined polycrystalline anatase structure was formed, characterized by grain development and nanostructure agglomeration, as evidenced by the increased intensity of diffraction peaks and higher surface roughness parameters. According to the XRD analysis, the average crystallite size ranged from 32 to 71 nm, depending on the synthesis temperature. The results demonstrate that deposition temperature exerts a comprehensive effect on both the phase composition and surface morphology of TiO₂ films, which must be considered for their application in functional nanostructures, photocatalytic systems, sensors, and microelectronic devices.

Design and Development of Ferrite-TiO₂ Nanocomposites with Tunable Magnetic Properties

2025-12-07T22:09:21+00:00

Ni-ferrite-TiO₂ nanocomposites with varying TiO₂ content (0%, 25%, 50% and 75%) were synthesized using the sol-gel auto-combustion method and characterized through XRD, FE-SEM, VSM, and Raman spectroscopy. The XRD analysis confirmed the coexistence of ferrite and TiO₂ phases. FE-SEM images revealed uniform particle distribution and a reduction in particle size as TiO₂ content increased. Raman spectroscopy showed strong TiO₂-related vibrational modes, with the highest intensity observed in the 75% TiO₂ sample, diminishing as TiO₂ content decreased. Peaks observed in pure Ni-ferrite (283, 402, 469 and 689 cm⁻¹) shifted to lower wavelengths with increasing TiO₂ doping, indicating altered vibrational modes due to phase interactions. These interactions likely contributed to changes in the magnetic properties. VSM analysis revealed a decrease in saturation magnetization and magnetic remanence with increasing TiO₂ content, while coercivity remained stable. The magnetic behavior was attributed to TiO₂ dilution and phase interfaces, offering valuable insights for the design of magnetic materials with customized properties.

Study of the Influence of Temperature on the Transitions of the CdS/Si/CdTe Heterosystem

2025-12-07T22:09:23+00:00

The study presents the results of an investigation into the temperature dependence of the current–voltage characteristics of CdS/Si/CdTe heterostructures fabricated by thermal evaporation. The study establishes that, as the temperature increases, an exponential rise in current is observed, attributed to the thermally activated nature of conductivity and the reduction of the potential barrier at the interfacial boundaries. In the low-temperature region, the structure exhibits diode-like behavior, whereas at higher applied voltages (20–40 V), an injection transport mechanism becomes dominant. The activation energy of 0.61 eV confirms that the thermal release of carriers from localized states governs charge transport. The results indicate the stability of the barrier height and conduction mechanism over the studied temperature range, highlighting the need to account for thermal effects in the design of photoelectric and optoelectronic devices based on CdS/Si/CdTe structures.

DFT-Based Study of TlX and BX (X= N, P, As) Compounds: A Comparative Insight into Structural, Electronic, and Optical Behavior

2025-12-07T22:09:25+00:00

This work presents a detailed theoretical investigation of the structural, electronic, and optical properties of thallium-based (TlX) and boron-based (BX) compounds, where X = N, P, As, within the zinc-blende crystal structure. First-principles calculations were performed using density functional theory (DFT) within the generalized gradient approximation (GGA). The obtained results reveal that Tl-based compounds exhibit lower total energies compared to BX compounds, indicating higher structural stability. In terms of electronic behavior, BX compounds maintain their semiconducting nature. In contrast, TlX compounds show metallic or near-metallic characteristics due to the absence of an energy gap at the Fermi level. Furthermore, optical investigations demonstrate that TlX compounds possess higher static refractive indices and stronger absorption features in the low-energy region. These findings highlight the potential of Tl-based compounds for future applications in optoelectronic and photonic devices. Overall, this comparative study provides valuable insights for the design of advanced materials for electronic and energy-related technologies.

Phase Transformations and Structural Transformations of Manganese Silicides in the Si-Mn System

2025-12-07T22:09:27+00:00

A comprehensive investigation of thermally induced phase transformations in the silicon-manganese (Si–Mn) system was conducted. The study utilized X-ray diffraction (XRD), Raman spectroscopy (including chemical Raman mapping), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS), deep-level transient spectroscopy (DLTS), and thermodynamic CALPHAD modeling. The sequence of transformations has been reliably reconstructed as follows: (i) interstitial incorporation of Mn and partial amorphization of the near-surface Si layer; (ii) nucleation and growth of MnSi (B20 structure, P2₁3); (iii) stabilization of the higher silicide phase Mn₄Si₇ under Si-rich conditions; (iv) at T ≫ 900 °C, a partial reverse transformation to MnSi. DLTS analysis revealed three electrically active deep-level centers with activation energies of Eс–0.53 eV, Eс–0.43 eV, and Eс–0.20 eV (σ_n ≈ 10⁻¹⁶–10⁻¹⁵ cm²), which correlate with the MnSi → Mn₄Si₇ transition and interface traps at the “silicide/Si” boundary. CALPHAD modeling confirmed negative Gibbs free energies of formation (ΔGf) and identified thermodynamic stability windows for MnSi (600–750 °C) and Mn₄Si₇ (800–950 °C). The resulting process map provides the technological parameters for synthesizing CMOS-compatible Si–Mn structures.

Analysing the Structural, Electronic and Optical Properties of Ca₃PCl₃ Perovskite for Its Applicability in Green Energy and Optoelectronic Applications

2025-12-07T22:09:29+00:00

The objective of this research is to provide a detailed examination of the ways in which perovskite Ca₃PCl₃ can be improved for its efficiency in optoelectronic and solar cell field. The substance known as Ca₃PCl₃is classified in the same category as perovskites that are composed of inorganic metal halides. In the scope of this study, the density functional theory (DFT), that are the base principles, were used to examine the optical, electrical, and structural characteristics. The generalized gradient approximation (GGA), the Perdew Burke–Ernzerhof functionals and the linear combination of atomic orbital calculator are the tools that are utilized in order to gain an understanding of the characteristics of the Ca₃PCl₃ perovskite. The key point includes the material’s direct band gap which is measured to be 20.35eV at the Г-point. It has also been discovered that the dielectric function and the absorption spectra change depending on the energy of the photon. It has been reported that the value of the extinction coefficient is 3.6963× 10⁴, and the value of the reflecting index is 1.4410. Therefore, studying Ca₃PCl₃'s optical properties is crucial for considering this material for future use in photovoltaic and optoelectronic devices.

Local Variation of Scattering Light Intensity in Manganese Ion Implanted Silicon Single Crystals

2025-12-07T22:09:31+00:00

This article presents the results of experimental studies of local changes in the scattered light intensity and surface morphology in Mn implanted single-crystal silicon samples with electron conductivity and [100] crystalline orientation. The manganese ion energy, implantation dose, and phosphorus concentration in substrate were 40 keV, 5⋅10¹⁵÷1⋅10¹⁷ ion/cm², and ~ 9,3⋅10¹⁴ cm^–3, respectively. Atomic force microscopy (AFM) and Raman spectroscopy, using the backscattering geometry of surface-scattered light, were applied to analyze the surface morphology before and after implantation. AFM micrographs of the surface show characteristic nanometer-sized roughnesses, the shape and size of which strongly depend on the implantation dose. These nanoscale objects are not present on the non-implanted substrate surface. In the Raman spectra of the samples not subjected to implantation, the main Lorentz-type peak is always observed, which is characteristic of single-crystal silicon and centered at 520.0±1.0 cm⁻¹, corresponding to the phonon wave vector. Several peaks are observed in the Raman spectra of manganese ion-implanted silicon samples (184, 291, 373, 468, 659, 798, and 804 cm⁻¹), presumably associated with the formation of radiation defects and nanoscale objects on the surface of single-crystal silicon during ion implantation with the participation of silicon, manganese, phosphorus, and other impurity atoms. These structural defects in the silicon crystal lattice at the surface and near-surface caused by manganese ion bombardment lead to the excitation of new vibrational modes not observed in the initial silicon. These modes are manifested in Raman scattering spectra.

Lie Algebraic Modeling of Vibrational Frequencies in Hexachlorobenzene: A Symmetry-Adapted Approach for the D₆ₕ Point Group

2025-12-07T22:09:35+00:00

This work uses a symmetry-adapted Lie algebraic framework to study the vibrational frequencies of hexachlorobenzene (C₆Cl₆). A U(2)-based vibrational Hamiltonian captures the fundamental modes and the first and second overtones by exploiting the molecule's D_6h point group symmetry. The algebraic approach considers anharmonicity and symmetry constraints to provide a compact and manageable analytical portrayal of the vibrational spectrum. The computed fundamental frequencies agree strongly with the observed values, validating the approach. Moreover, the extension to overtones underlines the algebraic model's capability to evaluate higher-order vibrational excitations in polyatomic molecules systematically. These results confirm the effectiveness of Lie algebraic methods in modelling vibrational features of highly symmetric molecules and serve as a solid basis for further work in molecular spectroscopy.

Dielectric Constants and Transverse Effective Charges in the Quinary Alloy GaxIn1-xNySbzAs1-y-z Lattice Matched to InAs, GaSb and GaAs

2025-12-07T22:09:38+00:00

This study provides a comprehensive theoretical analysis of the dielectric properties and transverse effective charges of the pentanary alloy Ga_xIn_1-xN_ySb_zAs_1-y-z, focusing on compositions that are lattice-matched to InAs, GaSb, and GaAs substrates. The investigation employs the local empirical pseudopotential method (EPM) in conjunction with the virtual crystal approximation (VCA) and the Harrison bond-orbital model to evaluate key parameters, including the static and high-frequency dielectric constants, ionicity, polarity, and transverse effective charge. These computational approaches were chosen due to their ability to accurately describe electronic interactions in complex alloy systems while maintaining computational efficiency. The obtained results demonstrate notable consistency with experimental data available for the constituent binary compounds, reinforcing the reliability of the theoretical framework. Additionally, the study reveals systematic trends in the dielectric behavior as a function of composition, providing insights into the role of atomic substitution in tuning these properties. To the best of our knowledge, this work represents the first detailed theoretical assessment of Ga_xIn_1-xN_ySb_zAs_1-y-z alloys in this context. While experimental validation remains necessary, our findings establish a valuable theoretical benchmark for future studies and potential applications in optoelectronic and semiconductor device engineering, particularly in the design of advanced infrared detectors and high-frequency electronic components.

Effect of Boric and Oxalic Acid on Nucleation Mechanism, Composition, Morphology and Structure of Electrodeposited Ni Films

2025-12-07T22:09:40+00:00

Nickel thin films were electrodeposited onto copper substrates at room temperature using an aqueous electrolyte containing nickel sulfate, nickel chloride, and sodium sulfate. The effects of two additives (boric acid and oxalic acid) on the nucleation mechanism, crystallographic structure, surface morphology, and chemical composition of the resulting Ni films were systematically investigated using cyclic voltammetry (CV), chronoamperometry (CA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). CV analysis revealed that the presence of additives shifted the cathodic peak potentials toward more negative values, suggesting an inhibition effect on nickel reduction. Chronoamperometric studies confirmed that Ni deposition followed a three-dimensional instantaneous nucleation mode, unaffected by the additives. XRD patterns showed that all Ni films had a face-centered cubic (FCC) structure with strong (111) orientation, while SEM images indicated denser and more homogeneous surface morphology in the presence of additives. EDS analysis confirmed the presence of Ni in all samples.

Emittance of a Low-Power RF Ion Source with a Micrometer-Scale Extraction Aperture

2025-12-07T22:09:42+00:00

The concept of a compact nuclear microprobe is based on specialized ion sources with beam currents not exceeding a few nanoamperes and a small energy spread. At the Institute of Applied Physics, NAS of Ukraine, a low-power RF ion source has been developed for application in a compact nuclear microprobe. The source operates at low RF power (< 10 W) and is designed to generate a ¹H⁺ ion beam required for standard techniques such as PIXE, RBS, and proton beam writing. To reduce the beam emittance and improve the spatial resolution of the microprobe, the source extraction aperture diameter was reduced to 50 μm. This paper reports measurements of the total beam current and emittance extracted from the low-power RF ion source with a micrometer-scale extraction aperture. Data on the beam profile, its diameter, and divergence angle are also presented. The main parameters of the RF source are as follows: quartz chamber diameter – 34 mm, length – 70 mm, working gas – hydrogen, extraction aperture diameter – 50 μm, RF power ≤ 10 W, frequency – 45 MHz, ion current up to 100 nA. The extraction voltage varies from 10 to 300 V, while the beam energy ranges from 1 to 6.5 keV. Beam emittance was measured using an electrostatic Allison-type scanner. The minimum emittance containing 90% of the total beam current was found to be ε₉₀ = 1.36 π∙mm∙mrad, while the rms-emittance is ε_rms = 0.32 mm∙mrad. The normalized emittance is ε_N = 0.003 π∙mm∙mrad, and the energy-normalized emittance equals 0.1 π∙mm∙mrad∙(MeV)^1/2. It is shown that reducing the diameter of the extraction aperture of the ion source to 50 μm results in a significant improvement in the ion-optical characteristics of the extracted beam.

Second Harmonic Generation of High-Power Elliptical Beam in Thermal Quantum Plasma

2025-12-07T22:09:45+00:00

The current study investigates second harmonic generation of elliptical beam in thermal quantum plasma (TQP) by taking relativistic-ponderomotive (RP) forces together. There is change in mass of electrons due to RP force thereby producing change in background density profile in a direction transverse to main beam. The main beam gets self-focused. The established density gradients excites electron plasma wave (EPW) at pump wave frequency. The excited EPW further interacts with pump wave to produce second harmonic generation (SHG). The widely accepted WKB and paraxial approximations are employed for deriving the 2^nd order ODEs for semi major and semi-minor axes of elliptical beam with normalized propagation distance and efficiency of second harmonics. Furthermore, the influence of varying suitable laser-plasma parameters on beam waist dynamics and efficiency of 2^nd harmonics are also explored.

Estimating the Total Dose of X-Ray Bremsstrahlung from a Powerful Pulsed Source Driven by A High-Current Electron Beam

2025-12-07T22:09:48+00:00

The paper reports the results of measuring the total dose of X-ray bremsstrahlung from a powerful X-ray source based on the high-current pulsed direct-action electron accelerator “Temp-B”. The parameters of the high-current, tubular relativistic electron beam from the accelerator were as follows: energy 600 keV, current 13.5 kA, and pulse duration 1.0 μs. Using the pulsed magnetic field of a solenoid, the electron beam generated in a magnetically isolated diode was transported over a 55 cm distance toward the molybdenum converter. An auxiliary coil, connected in series with the solenoid, was placed adjacent to it to provide the desired magnetic field in the converter region and avoid beam losses. The methodology for determining the total dose of the produced X-ray bremsstrahlung is described. Polycrystalline detectors were used for measuring the X-ray bremsstrahlung dose. They were located 80 mm behind the converter in the polar plane, with a 20° separation. Measurements of the dose distribution over the polar angle showed symmetrical distributions of the radiation at both polar and azimuthal angles relative to the axis. Taking into account such symmetry and the fact that the electron beam radiates solely into the forward hemisphere, the integration over the entire sphere can be reduced to integration over just a fraction of 1/8 of the spherical surface, thereby reducing the required number of sensors. The experimentally obtained value of the total dose of the X-ray bremsstrahlung is 388.5 Gy per single pulse of the accelerator current, which is concentrated in a 120° cone in the direction of the beam movement.

Fast Neutron Discrimination Using the Stilbene Scintillator

2025-12-07T22:09:52+00:00

In this research, we have studied a speed system for neutron flux estimation used in experimental works with radiation protection design and for applications where materials identification based on neutron backscattering is crucial. The most effective approach is neutron-gamma discrimination using the stilbene scintillator. We performed a discrimination with the charge integration technique. The data acquisition was implemented using a high sampling rate oscilloscope. Crystalline stilbene is an organic scintillator that is well-suited for fast neutron identification in environments with high gamma-ray-associated irradiation.

Optimizing Head and Neck Cancer Radiotherapy: A Dosimetric Comparison of FF and FFF Beams in VMAT

2025-12-07T22:09:55+00:00

Aim: Head and neck cancer (HNC) is a significant global health concern, with rising incidence rates and a high prevalence in South Asia, particularly in India. Radiation therapy, including advanced techniques like Volumetric-Modulated Arc Therapy (VMAT) and Intensity-Modulated Radiotherapy (IMRT), plays a crucial role in treating HNC. This study aims to compare the dosimetric and biological and second cancer risk estimation differences between flattened (FF) and flattening filter-free (FFF) beams in VMAT treatment plans for HNC, focusing on the impact of 6 MV and 10 MV energies.
Methods: Twenty HNC patients underwent replanning using VMAT on an ELEKTA VERSA HD linear accelerator with 6 MV FF, 6 MV FFF, 10 MV FF, and 10 MV FFF beams. Dosimetric parameters evaluated included dose distribution to planning target volumes (PTVs) and dose delivered to 98% of the target (D98), 50% (D50), and 2% (D2), as well as doses to organs at risk (OARs)., monitor units per segment (MU/Segment), number of MU/cGy, treatment delivery time, conformity index, and homogeneity index, also biological parameters (NTCP and EUD) and second cancer risk estimation were evaluated.
Results: The results showed that 6 MV FFF beams provided slightly better dose-sparing for OARs compared to 6 MV FF, with no significant differences in target volume coverage. Both FF and FFF beams demonstrated comparable conformity indices, but FF beams had better homogeneity indices. FFF beams required more monitor units (MUs) and segments but offered reduced treatment delivery times. For 10 MV beams, FFF showed marginal advantages in dose homogeneity and sparing of normal tissues at lower doses, though it required more MUs and segments, this study found that NTCP and EUD were largely comparable between FF and FFF types, with minor but statistically significant differences for the brainstem (favoring FFF) and heart. Second cancer risks varied slightly by energy and technique 6MV FFF reduced parotid risks (though increased larynx risk).
Conclusion: 6 MV beams, particularly FFF, showed slight advantages in sparing OARs and target volume coverage compared to 10 MV beams. This study highlights the dosimetric comparability of FF and FFF beams in HNC treatment, with FFF offering potential benefits in treatment efficiency and reduced delivery times. This study also shows that FF and FFF types yield comparable radiobiological outcomes, though 6MV FFF beams slightly reduce doses to critical organs without sacrificing efficacy. Both types perform similarly, with minor risk variations by energy.

Development and Evaluation of 3D-Printed Homogeneous and Heterogeneous Phantoms for Quality Assurance in Radiation Therapy

2025-12-07T22:09:58+00:00

Background: Affordable and locally manufacturable quality assurance (QA) phantoms are critical for maintaining accuracy in radiation therapy, particularly in low-resource settings. This study evaluates the radiological and dosimetric performance of 3D-printed homogeneous and heterogeneous phantoms against commercial standards.
Methods: Two phantom prototypes were developed: a homogeneous model fabricated from PMMA and a heterogeneous model composed of EVA, PLA, MDI-based foam, and gypsum–chalk composite. Radiological properties were assessed using CT imaging with three reconstruction kernels (Hp38, Bf39, Hr32) at slice thicknesses of 1–3 mm. Hounsfield Units (HU) were compared with reference values from the Easy Slab (IBA) and CatPhan 604. Dosimetric validation was performed with Eclipse TPS (v16.1) using 15 3D-CRT and 15 VMAT plans, delivered on Varian TrueBeam (6 MV, 6 MV FFF, 10 MV, 10 MV FFF) and Halcyon (6 MV FFF) accelerators. Point doses were measured with a calibrated Farmer chamber.
Results: The homogeneous PMMA phantom demonstrated HU stability within ±5 HU of the reference values across all kernels, with standard deviations of less than 3 HU. EVA and gypsum–chalk provided tissue-equivalent and bone-equivalent imaging properties (20 ± 3 HU and 1200 ± 15 HU, respectively), while PLA and MDI foam demonstrated excessive variability (>40 HU kernel dependence). Dosimetrically, the homogeneous phantom achieved agreement with TPS calculations within ±2.5% across all energies and techniques. The heterogeneous phantom exhibited deviations of up to 2.8%, remaining within the ±3% tolerance of AAPM TG-119. Variability was most significant for VMAT plans with FFF beams, particularly on the Halcyon platform.
Conclusion: A 3D-printed homogeneous PMMA phantom demonstrated radiological stability and dosimetric accuracy comparable to that of commercial devices, confirming its feasibility for routine QA. The heterogeneous model exhibited acceptable performance but requires material refinement, particularly substitution of PLA and MDI foam, to improve HU stability. These results highlight the potential of additive manufacturing to provide cost-effective, customizable QA solutions for radiation therapy, especially in resource-limited environments.

Monte Carlo Code for Calculating the Elastic and Inelastic Scattering Cross Section Along with Mean Free Path of Positron Scattering in Kidney, Lung and Thyroid Organs

2025-12-07T22:10:00+00:00

This research calculated the total cross sections for positron scattering in kidney, lung, and thyroid tissues along an energy range of 100 eV to 1 MeV. Monte Carlo methods were employed to determine both elastic and inelastic integral cross sections, utilizing the Rutherford formula for elastic scattering and the Gryzinski excitation function for inelastic processes. A comparison was made between elastic and Penelope elastic cross sections. The study also examined elastic, inelastic, and total mean free paths as functions of positron energy for all three tissue types. The computational approach is designed to be broadly applicable across different materials. We observed significant differences in cross-section profiles and in the energy dependencies of the mean free path between tissues, attributing these variations to distinct inelastic-scattering characteristics inherent to each material. While the systematic uncertainties in the computational algorithm are challenging to quantify precisely, we believe they are largely systematic.

Input Characteristics of Electrically Thin Dipole with Variable Radius Along Antenna Length

2025-12-07T22:10:02+00:00

An approximate analytical solution to the problem of radiation (diffraction) of electromagnetic waves by dipole (monopole) with variable radius along antenna length is presented. The solution was carried out using generalized method of induced electromotive forces (EMF). An influence of the change of monopole radius upon input characteristics is numerically studied. Theoretical results are compared with the experimental data.

Effect of TiO₂ Layer Thickness on Electrode Degradation in Redox Flow Batteries

2025-12-07T22:10:03+00:00

In this work, TiO₂ coatings of various thicknesses were deposited on carbon felt fibers using the ALD (Atomic Layer Deposition) method, and the mechanical and electrochemical properties of the electrodes were studied. The experimental results show that the TiO₂ coating effectively protects and enhances the stability of carbon wet electrodes. While a mass loss of 4% was observed in the untreated cathode electrode, this figure decreased to 1.6-1.7% when a TiO₂ coating was applied. When the coating thickness was increased from 50 nm to 300 nm, no significant change in mass loss was observed, which indicates that even thin coatings provide effective protection. The mass loss in the anode electrode was relatively small, ranging from 2% in the untreated state and 0.5-1.1% in the coated states. This is explained by the lower anode potential than the cathode and the low sensitivity of the V²⁺/V³⁺ redox reaction at the anode. It was found that the titanium dioxide coating plays an important role in increasing the electrochemical degradation and corrosion resistance of the electrodes, as well as in extending the battery life. It was also shown that a 50 nm thick TiO₂ coating can provide effective protection, while very thick coatings can limit electron mobility. These results confirm that TiO₂ coatings are one of the promising solutions for protecting electrode materials in vanadium flow batteries.

Simulation of Focusing a Hollow Electron Beam by the Symmetric Magnetic Lens for Industrial Application in Additive Technologies

2025-12-07T22:10:07+00:00

The article studies the focusing features of a short-focus hollow electron beam formed from a wide surface of a cold cathode in high-voltage glow discharge electron guns using numerical simulation techniques. Such a type of electron beam is widely used today for producing new kinds of metals with unique properties by melting wire, which moves in a vertical direction through the ring-like beam focus. After that, the melted metal is crystallized on the horizontally moving substrate, which is located near the focus of the electron beam below. Such modern technology is considered three-dimensional printing of metal, or additive technologies. The original software created by the authors in the Python programming language has been used to obtain the corresponding simulation results. Analysis of the obtained numerical simulation results proved that with a small change in the beam trajectory divergence angle or the radius of the initial point on the cathode surface, the beam focus position, as a rule, does not change. Therefore, the annular focus of the beam is usually in a stable position on the longitudinal coordinate, and the thickness of the focal ring is always in the range of several millimeters. The corresponding theoretical results were compared with experimental data, and the difference between the theoretical and experimental results is in the range of 10-15% depending on the accelerating voltage and size of the cathode surface. High-voltage glow discharge electron guns with such parameters, by the thickness of the focal ring, can be successfully used in advanced industrial additive technologies for three-dimensional printing on metal surfaces by uniform heating along the perimeter of moving wires or rods with a variable diameter in the range of 0.5 – 10 mm.

The Impact of Various Lighting Conditions on the Photosensitive Properties of Si and Si Structures

2025-12-07T22:10:09+00:00

The paper analyses the results of experimental studies carried out to investigate the photosensitive properties of Si<B,S> and Si<B,Rh> structures under the influence of various types of radiation. It was found that the sensitivity of photodiodes fabricated on the basis of Si<B,S> and Si<B,Rh>, increases several times (from 0.35 to 2.6 A·W¹) at decreasing temperature (from 300 K to 77 K). The threshold sensitivity of Si<B,S> based photodetectors was found to be significantly higher compared to Si<B,Rh> based photodetectors (Φ ≈ 1.2-10^-11 lm·Hz^-1/2). Increasing the concentration of sulphur (S) or rhodium (Rh) in silicon increases the photosensitivity, but the sensitivity decreases 3-4 times when the permissible concentration is exceeded (N_Rh> 2.6-10¹⁵ cm^-3). It was found that photodetectors based on Si<B,S> and Si<B,Rh> retain their sensitivity parameters at high levels of radiation exposure (under the action of protons, neutrons, electrons, and γ-quanta). In diodes based on p⁺-n-p-n⁺, an S-shaped I-V characteristic is observed, as well as the disappearance of the gating voltage (U_sp = 0.5÷10 V) with increasing temperature. Relaxation of photoconductivity in diodes based on Si<B,S> and Si<B,Rh> is due to the increase in the lifetime of charge carriers.

Impact of Donor-Acceptor Positions to Tune Efficient Dye-Sensitized Solar Cells: DFT/TD-DFT Study

2025-12-07T22:10:11+00:00

The anthracene molecule was adopted as a π-conjugation bridge for the D–π–A system with a nitro group CH3 and a nitro group NO2 acting as donor and acceptor groups. The influence of the anthracene nature junction with the donor and acceptor sides was evaluated on the performance of a dye-sensitized solar cell (DSSC). The donor and acceptor positions in this study changed around the anthracene. Density functional theory (DFT) has been utilized at the B3LYP theory level. The donor group could bind to anthracene at two specific sites, while the acceptor group could bind to the remaining anthracene sites, excluding the donor group site. The photovoltaic and electronic properties have been investigated. The results showed that the best-performing molecular dyes, D₁₀A₇, D₁₀A₈, and D₁A₆, are suitable for use as sensitizers due to their energetically favorable photovoltaic parameters, which are attributed to the potential for electron injection and regeneration.

Calculated Forbidden Bandgap of Si₃MnS Phase in Supercell (1Х1Х3) and Experimentally Determined Forbidden Bandgap of Si

2025-12-07T22:10:13+00:00

The paper presents the results of a quantum chemical calculation of a hypothetical Si₃MnS structure representing a “hybrid” of the cubic lattice of silicon Si and sphalerite ZnS. The Si lattice with a diamond structure, scaled up to a supercell (1X1X3), has been chosen for further study and calculation. Several assumptions have been made regarding the most likely substitutional sites for S and Mn impurity atoms in the Si crystal lattice. The corresponding Si₃MnS phase is expected to form in the first coordination shell. For quantum chemical calculations, the Quantum ESPRESSO suite for first-principles electronic-structure calculations and materials modeling has been adopted. The calculated forbidden bandgap of Si₃MnS phase in a (1х1х3) supercell turns out to be 1.14 eV. Also, the current-voltage characteristics of Si<Mn,S> samples with p-n junction have been measured by applying the technique of temperature scanning at two comparatively low and nearly adjacent temperatures with the aim to determine the experimental forbidden bandgap energy value. The original n-type single-crystal silicon (phosphor-doped, specific resistance 100 Ω·cm) and p-type single-crystal silicon (boron-doped, specific resistance 1 Ω·cm) were used as initial materials for the experiments. An attempt has been made to perform a comparative analysis of forbidden bandgap values determined both during quantum-chemical calculations of the density of electronic states of the Si3MnS phase and during experimental measurements. Thorough quantum chemical calculations of IV/III-V and IV/II-VI-type “hybrid” structures in the cubic lattice of silicon and experimental measurements could incidentally shed light onto the possibility of engineering high-performance structures for future solar cells based on single crystal silicon.

Effect of Stoichiometric Distortions on Electrical and Photoelectric Properties of Layered GeS Crystal

2025-12-07T22:10:15+00:00

The current-voltage characteristic, electrical conductivity, thermally stimulated current, and photoelectric properties of a layered GeS crystal with excess sulfur were investigated under an external electric field of 10-104 V/cm and at temperatures of 100-300 K. It was found that donor-type defects formed as a result of stoichiometric distortion due to excess sulfur in a GeS crystal obtained by the Bridgman method, leading to impurity conductivity. Charge transport occurs by a monopolar injection current limited by the volume of the charge region. It was found that thermal activation of photocurrent and thermal quenching of photocurrent in doped GeS crystals are associated with electron exchange between capture traps and recombination centers.

Production of Magnetic Nanoparticle-Based Ferrites and Comprehensive Characterization of Their Electrical and Magnetic Properties in Colloidal Systems

2025-12-07T22:10:16+00:00

This study investigates the synthesis, structural characterization, and physicochemical properties of magnetic nanoparticles derived from iron group metals (Fe, Co, Ni) and their corresponding ferrite dispersions. Magnetic nanoparticles were synthesized via chemical condensation, and their morphology and structure were analyzed using transmission electron microscopy (TEM) and X-ray diffraction (XRD). The synthesized magnetic nanoparticles, comprising Fe₃O₄, CoFe₂O₄, and NiFe₂O₄ferrites, exhibited nano-scale dimensions ranging from 10 to 50 nm. The precise correlation between TEM and XRD measurements validated the structural and dimensional characteristics of the synthesized nanoparticles. Aqueous-based magnetic liquids with varying nanoparticle concentrations were prepared, enabling systematic investigation of their electrical conductivity and magnetic susceptibility at ambient temperature. The experimental findings provide critical insights into the fundamental properties of magnetic nanoparticle-based colloidal systems, potentially facilitating advanced applications in materials science, magnetic device engineering, and emerging technological domains. The methodological approach and results presented herein contribute to the expanding understanding of magnetic fluid behavior and performance.

Assessment of the Operating Temperature of Absorber Assembly Structural Components and Confirmation of Their Cooling Reliability in VVER-440 Reactor Core

2025-12-07T22:10:17+00:00

The specific energy release in the structural materials of the absorber assembly (control part of the accident control assembly – ACA, also known as the shim assembly) has been calculated. It depends on the power of the fixed fuel assemblies (FAs) in adjacent cells. The value of the energy release is 17.5 W/cm³ on the most loaded section of the boron absorber insert for an average Kq=1.28 over sectors. The total energy release in the structural materials of the absorber assembly, in the coolant, and in the connecting bar material is 229 kW for fully inserted controls and 64 kW for controls lifted up by 154.8 cm from the core bottom. The surface temperature distribution in the absorber insert along the absorber assembly height is conservatively calculated based on the total energy release in the absorber insert material and the amount and rate of coolant flow through it. At a coolant temperature around the absorber insert corresponding to the maximum coolant heating in adjacent fixed FAs (46.6 °C), and in the absence of axial heat exchange, the maximum surface temperature of the absorber insert for fully inserted controls will be 312.7 °C (outer surface), and for controls lifted from the core bottom to 154.8 cm – 317.1 °C (inner surface), giving a margin to saturation of 14.3 °C and 9.9 °C, respectively, at a coolant saturation temperature of 327 °C. In the most conservative case considered in this paper, the maximum surface temperature of the absorber insert is lower than the coolant's saturation temperature. This indicates the absence of bulk and surface boiling of the coolant under operation of the most energy-loaded component, i.e., the absorber insert of the absorber assembly, meaning that the structural components of the absorber assembly will be reliably cooled in the VVER-440 reactor core.

Experiment Details in Time Resolution Measurements of LYSO Scintillator

2025-12-07T22:10:20+00:00

In this research, we have performed experimental measurements of coincidence time resolution with a custom-built testbench. In the scope of this work, we discussed technical issues and data validation in the CTR experiment on an example of Saint-Gobain 4 x 4 x 4 mm lutetium-yttrium oxyorthosilicate (LYSO) crystals. The primary objective of the presented experimental works is to develop instruments for the experimental validation of newly created scintillation materials, as a step toward way the 10-ps time-of-flight PET challenge.

Polarization Effects in Si-n-p Radiation Receivers

2025-12-07T22:10:21+00:00

This paper presents a comprehensive analysis of n-p junction currents and polarization effects in diffusion Si detectors (receivers) for radiation. The mechanisms of polarization induced by charge-carrier capture at localized centers and the formation of space charge in the detector's sensitive region are investigated. The relationship between the presence of "large-scale" traps, which are local clusters of impurity atoms, and the appearance of anomalous spectral characteristics in the form of doublets has been established. It has been experimentally shown that ultrasonic treatment of Si-n-p detectors leads to a significant reduction in polarization effects due to the redistribution of impurity atoms and smoothing of the potential relief in the semiconductor structure. A physical model is proposed to explain the mechanism by which ultrasonic influence affects the electrophysical and spectrometric characteristics of silicon detectors. The results obtained have practical significance for optimizing production technology and improving the operational parameters of Si‑n-p radiation detectors.

Simulation of Tunnel Diode I–V Characteristics with Photocurrent and Phonon-Assisted Processes

2025-12-07T22:10:23+00:00

In this paper, a unified current model for tunnel diodes has been developed. The model incorporates not only the tunneling, diffusion, and excess currents but also the photocurrent generated under illumination. In addition, phonon-assisted tunneling processes, namely phonon absorption and phonon emission, arising from electron–phonon interactions, have been included. The calculated current–voltage characteristics indicate that the total current shifts downward under illumination. It is demonstrated that the photocurrent increases proportionally with the optical intensity and wavelength. In the case of phonon absorption, electrons gain additional energy, the tunneling channel broadens, and the peak current increases by approximately 15–20%. Conversely, during phonon emission, part of the electron energy is lost, reducing the tunneling probability, and the peak current decreases by about 10–12%. The obtained results indicate that accounting for phonon and photon processes significantly extends the application potential of tunnel diodes in optoelectronic and photodetector devices. The proposed model provides a theoretical basis for the development of tunnel diodes as high-frequency, light-sensitive, and energy-efficient devices.

Analysis of Radiation Methods for Explosive Materials Detection

2025-12-07T22:10:25+00:00

The paper examines the physical aspects of some landmine detection methods based on fast neutron backscattering. An analysis of the reaction products of the interaction of fast, slow, and thermal neutrons with H, C, N, O nuclei, which are part of explosive substances, was carried out. Mainly, to make it clear how to use secondary instantaneous and delayed gamma quanta emitted by the nuclei of explosive substances to achieve an increased detection efficiency. Discussed the physical features of some well-known methods of detecting explosive materials, exploiting elastic and inelastic scattering of fast neutrons. The reaction products of the interaction of fast, slow, and thermal neutrons with H, C, N, O nuclei included in explosives were analyzed. The goal was to simultaneously use both scattered fast and intermediate-energy neutrons emitted by the nuclei of explosives from elastic and inelastic scattering reactions (backscattering), as well as secondary instantaneous and delayed gamma quanta. The most suitable candidate for this role may be gamma-neutron detectors based on oxide scintillators of the ZWO type, which are simultaneously sensitive to both fast, slowed, and resonant neutrons, as well as to gamma quanta in a wide range of energies from tens of MeV to hundreds of eV. The using of a low-threshold single-photoelectron mode of photon registration makes it possible to significantly increases the sensitivity of the detection systems.

Raman Spectroscopy of Gamma-Irradiated Silicon Doped with Rhodium

2025-12-07T22:10:29+00:00

This study explores how gamma-ray exposure and rhodium (Rh) impurities affect the crystal structure of silicon using Raman spectroscopy. The introduction of rhodium into silicon single crystals causes subtle structural modifications and leads to the emergence of additional features in the Raman spectra. Specifically, the intensity of the characteristic silicon peak at 521 cm⁻¹ increases, while its full width at half maximum (FWHM) remains nearly constant. This enhanced peak intensity is likely a result of stronger bonding within the silicon lattice caused by Rh incorporation. Additionally, the new Raman signal observed at 245 cm⁻¹ in the Si<Rh> spectra is attributed to the presence of elemental rhodium and the formation of RhSi compounds. Further, irradiation of n-Si with gamma-rays with an energy of 1.25 MeV, a dose of 10⁷ rad leads to disruption and amorphization of the silicon crystal structure and to the creation of radiation vacancy defects. The results of irradiation of doped samples show that the introduction of rhodium atoms leads to a decrease in the amorphous part of silicon and to an improvement in the crystalline structure.

A Study of the Wear Resistance of TiMoN/NbN Nano-Multilayer Coatings Deposited by Ca-PVD Technology Under Different Working Pressures

2025-12-07T22:10:33+00:00

This study investigates the wear behaviour of TiMoN/NbN nano-multilayer coatings deposited by cathodic-arc PVD under two nitrogen working pressures (0.52 and 0.13 Pa). Although both coatings exhibit comparable total thicknesses (~10–11 μm) and a similar number of periods (~270), their structural integrity, interface coherence, and elemental distribution differ significantly with deposition pressure. The coating synthesized at 0.52 Pa develops a highly ordered, dense multilayer architecture, characterized by well-defined interfaces and a reduced microdefect density. Conversely, the coating deposited at 0.13 Pa displays pronounced interfacial waviness, disrupted periodicity, and increased defect concentration. Ball-on-disc tribological tests reveal a stable friction coefficient of 0.42–0.48 for the 0.52 Pa coating, whereas the 0.13 Pa coating shows an elevated and unstable friction response (0.60–0.70) with frequent fluctuations. Microstructural and chemical analyses of wear tracks indicate the formation of a robust, adaptive Ti–Nb–Mo–O tribofilm for the high-pressure coating, incorporating lubricious MoO₃ and mechanically strengthening Nb₂O₅ phases. In contrast, the low-pressure coating produces only a thin, brittle TiO₂-rich film lacking self-replenishing capability. These findings demonstrate that optimized nitrogen pressure is essential for achieving structurally coherent nanolaminates capable of forming functional tribofilms, thereby dramatically improving wear resistance in TiMoN/NbN nano-multilayer systems.

Polyphenol Effect on the Interactions Between Functional Proteins and Amyloid Fibrils

2025-12-07T22:10:37+00:00

Among a wide variety of protein-protein interactions, the complexation of functionally important proteins with pathogenic protein aggregates (amyloid fibrils) attracts particular interest in view of its possible contribution to amyloid cytotoxicity. In the present study we investigated the interactions between the functional proteins (human serum albumin (HSA), hemoglobin (deoxyHb and oxyHb) and insulin Ins)) and amyloid fibrils from Abeta peptide, islet amyloid polypeptide (IAPP), insulin (InsF), apolipoprotein A-I (apoA-I) and apolipoprotein A-II (apoA-II) with an accent on evaluating the possibility of modulating such interactions by polyphenolic compounds including quercetin, curcumin in keto and enol forms, gallic acid, salicylic acid, sesamin and resveratrol. The analysis of the molecular docking data showed that the binding affinities of amyloid fibrils to functional proteins vary in a wide range depending on the structural peculiarities of the examined systems. The most pronounced destabilizing effects of polyphenols on the complexes between the proteins in native and amyloid states were revealed for the systems HSA + QR / CRketo +ApoA-I, HSA +SES +IAPP, deoxyHb + SES / RES +InsF. Further experimental evaluation of these molecular docking predictions will create prerequisites for extending the range of polyphenol applications as anti-amyloid agents.

Assessment of the Sensitivity of a Fluorescent Squaraine Dye to Heavy Metal Ions

2025-12-07T22:10:42+00:00

The contamination of natural water systems with heavy metal ions poses a significant global environmental and public health threat due to their persistence, bioaccumulation, and severe toxicological effects. Consequently, the development of rapid and sensitive detection methods is essential for effective water quality monitoring. Squaraine dyes represent a promising class of chemosensors for heavy metal detection owing to their high molar extinction coefficients, near-infrared fluorescence, and pronounced spectral responsiveness to metal binding. In this study, we evaluate the sensitivity of the symmetric squaraine dye SQ-1 toward four environmentally relevant heavy metal ions – Cu²⁺, Zn²⁺, Ni²⁺, and Pb²⁺ – and explore its applicability within a β-lactoglobulin/SQ-1 nanosystem for metal sensing in aqueous media. Spectroscopic analysis revealed metal-dependent modulation of SQ-1 optical properties, driven largely by alterations in dye aggregation and metal–dye coordination. Ni²⁺ and Pb²⁺ promoted SQ-1 deaggregation and enhanced fluorescence emission, whereas Cu²⁺ induced pronounced quenching consistent with strong coordination. Our results indicate that, SQ-1 retained its responsiveness in the presence of β-lactoglobulin fibrils, exhibiting metal-specific fluorescence changes indicative of combined dye–metal–fibril interactions. Further studies are warranted to assess SQ-1 performance toward additional metal ions and to elucidate the molecular mechanisms underlying metal-induced modulation of its photophysical behavior.