Optical and Quantum Electronics最新文献

This study probes the structural, surface morphology, dielectric, photocatalytic, optical, magnetic and antibacterial properties of gadolinium-doped ZnO nanostructures synthesized using the sol–gel dip-coating route. In this article, the goal was to examine properties of ZnO nanostructures that were produced using a toxic-free wet chemical deposition method with Gd doping concentration manipulation. Fourier Transform Infrared Spectroscopy (FTIR) was used to identify the functional groups present in the prepared samples. X-ray diffraction (XRD) Spectra revealed the presence of a hexagonal wurtzite structure of ZnO. A slight shift in crystallite size was seen after adding Gd dopant to ZnO. Scanning Electron Microscope (SEM) micrographs of all prepared Gd-ZnO nanostructures confirmed their irregular and spherical-like morphology to be used as toxic gas sensors. The results of UV–VIS–NIR spectrophotometer exhibited an increment in the band gap of ZnO from 3.65 to 3.80 eV as the content of Gd dopant increased. Photocatalysis is a branch of electrochemistry that emerged from electron transfer reactions. Photo catalysts having 3 wt. % Gd showed the highest photo activity. The measured dielectric values of Gd-doped ZnO were considered to be the result of gadolinium doping. Gd -ZnO was found to be an antibacterial agent against all tested bacteria. These prepared nanostructures were recommended for pollutant degradation, microbial elimination and optoelectronic appliances.

This paper presents a graphene-based metamaterial biosensor designed for the detection of hemoglobin, utilizing finite element method (FEM) simulations. The proposed structure achieves a near-perfect absorption of 99.99% at a resonant frequency of 3.165 THz. Graphene’s inherent tunability is exploited to investigate the influence of chemical potential and relaxation time to optimize sensor performance. The resonance frequency shifts with changes in the surrounding medium refractive index (RI), enabling sensitive hemoglobin detection. In the presence of hemoglobin, the resonance shifts between 2.79 and 2.85 THz to determine its concentration. The biosensor exhibits a high sensitivity of 750 GHz/RIU, a quality factor of 35.16, and a figure of merit (FOM) of 8.33 RIU⁻¹, demonstrating strong potential for biomedical sensing applications.

Cd_xZn_(1−x)Se thin films were grown by the Successive Ionic Layer Adsorption and Reaction (SILAR) method on a glass substrate at room temperature. X-ray diffraction (XRD), thickness measurement, and room temperature and variable temperature absorption measurements were performed on each sample. XRD measurements have been shown that the thin films are polycrystalline and for CdSe c-axis is dominant while (111) direction is dominant for ZnSe film. SEM images show homogeneous surface coverage and a change in grain structure as the Zn content increases. The change in particle size was calculated using the Image J program. Absorption measurement showed that all the films are of acceptable optical quality. Bandgap of the CdSe and ZnSe thin films were determined as 1.88 and 2.68 eV, respectively. The bowing parameter of the ternary Cd_xZn_(1−x)Se thin films have been determined as 1.34.

Robust, tightly localized photonic modes are essential for scalable on-chip quantum information processing, including multi-plane (3D-integrated) photonic platforms in which multiple planar waveguide layers are vertically stacked and coupled. Here, we present a comprehensive study of three three-dimensional fractal photonic architectures, 3D Cantor dust, Vicsek fractal, and Sierpinski sponge, each discretized into dielectric voxels and modeled in a voxel-graph tight-binding surrogate with exponentially decaying evanescent-hopping couplings. We examine two imperfection classes: on-site refractive-index disorder (amplitude up to 10%) and stochastic voxel deletions (defect rate up to 2%). In a classical eigenanalysis (over 10 000 parameter combinations of waveguide width, layer thickness, baseline coupling, decay constant, and defect rate) we compute the central spectral spacing (Delta lambda ) (a finite-structure stopband proxy) and the inverse participation ratio, and demonstrate via ANOVA/Tukey HSD (adjusted (pll 10^{-3})) that 3D Cantor dust yields the largest mean central spacing and highest inverse participation ratio across depths and parameter ranges. Because the canonical Cantor-dust voxelization is disconnected under the unit-neighborhood coupling rule used in this paper, its high IPR should be interpreted as isolation-dominated localization within this surrogate. We additionally map the tight-binding coupling graphs to 2-local qubit Hamiltonians in the single-excitation manifold (one qubit per retained site), and we validate a variational quantum eigensolver workflow on a 2-qubit SSH dimer and on 4–8-qubit fractal subgraphs; the qubit counts, optimization objective, shot-based measurement model, and resource scaling with fractal iteration depth are stated explicitly. Our work positions 3D Cantor dust as a favorable multi-scale platform for graph-spectral stopband engineering and robust mode localization in tight-binding surrogates, motivating targeted full-wave electromagnetic validation and device-level studies of planar-mask implementations (stacked 2D fractal layers with vertical couplers) for 3D-integrated on-chip deployment.

The development of lead-free and environmentally benign absorbers is a critical step toward sustainable solar technologies. This study investigates the optoelectronic behavior and performance optimization of beryllium silicon diphosphide (BeSiP₂) based thin-film solar cells using SCAPS-1D simulation coupled with machine learning (ML) analysis. Various electron transport layers (ETLs) PCBM, SnO₂, WS₂, TiO₂ and hole transport layers (HTLs) V₂O₅, CuI, CuSCN, NiO were examined to determine the optimal device configuration. The optimized FTO/PCBM/BeSiP₂/V₂O₅/Cu–C device architecture achieved a high-power conversion efficiency (PCE) of 28.12%, with open circuit voltage (V_oc) = 1.13 V, Short Circuit Current Density (J_sc) = 29 mA cm⁻², and Fill Factor (FF) = 88%. Numerical analysis indicates that thin transport layers (50–100 nm), moderate doping concentrations (10¹⁷–10¹⁸ cm⁻³), and low interface defect densities (≤ 10¹⁴ cm⁻³) are critical in minimizing recombination losses and achieving this efficiency. To complement the numerical analysis, an ML framework utilizing eight regression algorithms was implemented to predict key photovoltaic parameters. Gradient Boosting (GB) achieved the highest accuracy (R² > 0.98), identifying shunt resistance (R_sh) and irradiance as dominant factors influencing device metrics. The hybrid SCAPS-ML approach effectively bridges physics-based and data-driven insights, enabling rapid, interpretable optimization of lead-free chalcopyrite solar cells.

A high-performance ultraviolet (UV) photodetector based on an n–TiO₂/p–Si heterojunction was fabricated using a cost-effective sol–gel spin-coating technique. The structural, morphological and optical properties of the anatase-phase TiO₂ thin films were systematically characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Raman spectroscopy and photoluminescence measurements. The fabricated heterojunction exhibited pronounced diode-like rectifying behavior under dark conditions, confirming the formation of a well-defined n–TiO₂/p–Si junction. Under UV–A illumination (365 nm), the device demonstrated a strong photocurrent response, while exhibiting only a negligible change in current under ambient visible illumination, indicating effective UV selectivity. Key photodetection parameters, including responsivity, detectivity and effective photoconductive gain were evaluated as a function of the applied reverse bias. The responsivity and detectivity increased monotonically with bias due to enhanced carrier collection efficiency, whereas the photo-to-dark current ratio (PDCR) decreased at higher bias voltages as a result of bias-induced dark current enhancement associated with depletion-width expansion and field-assisted leakage mechanisms. Maximum values of responsivity (~ 47 A W⁻¹) and detectivity (~ 1.1 × 10¹⁴ Jones) were achieved under reverse bias. The transient photoresponse exhibited rise and fall times of approximately 660 ms and 800 ms respectively. The photodetection mechanism is attributed to the combined effects of surface oxygen adsorption–desorption dynamics in the TiO₂ layer and the favorable band alignment at the n–TiO₂/p–Si interface, which forms a hole-blocking junction that facilitates efficient charge separation and electron transport. The reported gain values were estimated under the assumption of unity quantum efficiency and should therefore be regarded as effective photoconductive gain. Overall, the results demonstrate that sol–gel-derived n–TiO₂/p–Si heterojunctions offer a promising, low-cost platform for UV photodetection applications, with future work directed toward wavelength-dependent photoresponse and quantum efficiency measurements.

In many museums, archaeological glass covered with corrosion crusts does not undergo conservation cleaning. However, in Russia there is a tendency to clean corroded glass, and several methods are proposed in the specialized literature, but their long-term effect on the safety of glass and its chemical resistance has not been studied. The purpose of this work is to study the influence of conservation methods on the mechanism of reformation of corrosion under alkaline leaching conditions. For the study, methods of scanning electron microscopy with energy dispersive analysis, laser induced breakdown spectroscopy, and powder X-ray diffraction were used. As a result of the study, it was found that the duration of the artificial leaching cycle affects the mechanism of development of chemical degradation of glass. As for the conservation methods for cleaning glass, the method of boiling the sample in water with quartz sand turned out to be the closest in terms of the mechanism of corrosion development to the untreated test sample. The method of washing in a water-alcohol mixture, most often used in the conservation practice of Russian museums, turned out to be the most ineffective and unsafe for the chemical stability of glass.

This study presents a theoretical model for CdSe/ZnSe core-shell quantum dots that combines machine learning, coordinate transformation, and the finite difference method. The XGBoost (eXtreme Gradient Boosting) algorithm is employed to identify the dominant parameters that control core positioning within the model. We then investigate the optoelectronic properties of concentric and non-concentric nanostructures, analyzing the influence of core size and incident optical intensity I. The results demonstrate that key properties such as energy levels, inter-subband transitions, oscillator strengths, absorption coefficients, and refractive index changes can be tuned across the mid-infrared spectrum. This tunability is achieved through two complementary mechanisms: quantum confinement via core size and geometric control via structural symmetry. The findings demonstrate the utility of non-concentricity as a design parameter for tailoring the optoelectronic response of core-shell quantum dots.

This study presents an integrated computational, data-driven investigation, and photovoltaic performance of La₂NiMnO₆ (LNMO) for next-generation solar cell applications. Using SCAPS-1D and wxAMPS simulations combined with machine learning (ML) modeling, the device architecture FTO/WS₂/LNMO/CuSCN/Au was optimized for high efficiency and stability. The SCAPS-1D simulations revealed excellent photovoltaic performance, yielding a short-circuit current density (Jsc) of 32.92 mA cm⁻² and a power conversion efficiency (PCE) of 23.87%, accompanied by an open-circuit voltage (Voc) of 0.8650 V and a fill factor (FF) of 83.81%. Furthermore, Tb doping of the FTO layer significantly improved electrical conductivity and interfacial quality, leading to an enhanced device efficiency of 24.34%. This improvement was reflected in increased photovoltaic parameters, with Jsc, Voc, and FF reaching 33.52 mA cm⁻², 0.8657 V, and 83.89%, respectively. Parametric analysis demonstrated that optimal absorber thickness (600–800 nm), low defect density (10¹⁴-10¹⁵ cm⁻³), and reduced series resistance significantly improve carrier generation, reduce recombination, and maximize performance. Temperature and illumination studies confirmed high thermal stability with moderate efficiency losses at elevated conditions. Cross-validation with wxAMPS simulations and comparison with reported LNMO-based architectures confirmed the reliability of the proposed model. Machine learning algorithms yielded high predictive accuracy, with XGBoost achieving R² > 0.9998 and MSE < 0.005 for PCE prediction. This multidisciplinary approach demonstrates that LNMO, when combined with rare-earth doping and optimized interfacial engineering, is a strong candidate for high-efficiency, environmentally benign, and thermally stable lead-free perovskite solar cells.

The theoretical, numerical, and experimental demonstration of optical fraction-al-order integration is presented using a Fabry-Pérot interferometer made up of two fiber Bragg gratings. A spectral filtering behavior consistent with fractional-order integration is demonstrated by modeling the interferometer using the transfer matrix method and de-riving analytical expressions. It is shown that, under appropriate design conditions, the output light pulse corresponds to the mathematical result of applying a fractional integration operator to the input light pulse. This behavior is confirmed through numerical simulations and validated experimentally by fabricating a customized Fabry-Pérot interferometer, in which two fiber Bragg gratings are recorded in a photosensitive optical fiber. Analytical expressions relating the integration order to the reflectivity of a fiber Bragg grating are also derived, together with an analysis of the bandwidths that this optical de-vice can process. To the best of our knowledge, this is the first experimental demonstration of all-fiber fractional-order integration. The transmission of the fiber interferometer is experimentally characterized. Its performance as a photonic fractional integrator is demonstrated using light pulses as input. The results indicate that fractional-order operators can be implemented in an all-optical manner using fiber-optic technology.