We report highly sensitive NO2 gas sensors based on ZnO thin films prepared via a sol–gel method and deposited onto nanostructured black silicon (b-Si). The b-Si layers, fabricated using maskless reactive ion etching, consist of densely packed silicon nanoneedles with an average height of ~810 nm, a base diameter of ~160 nm, and a characteristic periodicity of ~190 nm. Owing to this highly developed surface morphology, the effective surface area of the b-Si layer is estimated to be approximately one order of magnitude higher than that of planar silicon, thereby enhancing gas adsorption and charge-transfer processes in the ZnO film. ZnO/b-Si/Si sensors exhibit a response of 448% at 25 ppm NO2 at an optimal operating temperature of 200 °C, which is approximately 1.5 times higher than that of planar ZnO/Si sensors at the same concentration and temperature. Notably, a comparable response (~300%) is achieved at a reduced temperature of 140 °C, indicating the potential for low-power operation. The sensing mechanism is governed primarily by the ZnO layer, while b-Si serves as a morphological scaffold, increasing the effective surface area. These results demonstrate that ZnO-coated b-Si nanostructures represent a promising platform for high-performance NO2 sensing and offer strong potential for integration with silicon-based microelectronic technologies.

This study elucidates the interfacial and optoelectronic properties of sol-gel-derived $\mathbf{Z n O}$ films deposited on nanostructured black silicon (b-Si) layers. The hybrid $\mathrm{ZnO} / \mathrm{b}-\mathrm{Si} / \mathrm{Si}$ architecture exhibits enhanced light-trapping (reflectance $\lt5 \%$ in the visible range), improved charge transport, and exceptional wettability $\left(\theta=38 \pm 3^{\circ}\right)$. Nanostructuring promotes conformal ZnO growth, boosts photoresponsivity ($1.16 \mathrm{~A} / \mathrm{W}$ at 850 nm), and reduces water spreading time to $\lt0.5$ s due to synergistic effects between ZnO surface chemistry and capillary action. These findings highlight the potential of engineered $\mathbf{Z n O} / \mathbf{b}-\mathbf{S i} / \mathbf{S i}$ heterostructures for high-performance optoelectronic devices, including sensors, photodetectors and solar cells.

In this work, zinc oxide (ZnO) films were deposited on silicon (Si) substrates with and without Black Silicon (BS) using the sol-gel spin-coating method. The nanotexturing of the Si surface was performed via reactive ion etching, resulting in the formation of a conical nanoneedle array that enhanced light trapping efficiency. X-ray Diffraction (XRD) analysis confirmed that the ZnO films exhibited a polycrystalline hexagonal wurtzite structure. The formation of n-ZnO/p-Si heterostructures was validated through Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and current-voltage (I–V) measurements. The incorporation of BS at the heterostructure interface significantly enhances the spectral response across the entire wavelength range due to superior light-trapping properties and an increased contact area at the heterojunction. These findings are highly relevant for the development of photodetectors and other optoelectronic devices based on ZnO and BS.

FTO, FTO:Ce, FTO:Ce films were synthesized by the sol-gel method and spray pyrolysis method. Their electrophysical and optical characteristics were determined. It was found that the introduction of graphene and cerium into the FTO films leads to an increase in electrical conductivity. High temperatures lead to graphene burnout and a change in the photoluminescence spectrum. Luminescence of Ce3+ and Ce4+ is observed in nanostructured thin films, its intensity in graphene-containing films decreases after carbon burnout. A wide luminescence band in the SL of the FTO:Ce film at 350-450 nm corresponds to the radiation of Ce3+, and the SL of the FTO:C:Ce film at 530-550 nm is identified as the radiation of Ce4+. The intensity of the luminescence band in graphene-containing FTO:C:Ce films decreases by 4.8 times compared to FTO:Ce films. The change in the charge state of the cerium ion is associated with its reduction during carbon burnout. The fact of graphene burnout is confirmed by a decrease in the electrical conductivity of the samples. The developed materials can be used in solar energy and optoelectronics.

This study reports the investigation of photoelectric behavior of the $\mathrm{Al} / \mathrm{ZnO}: \mathrm{MgO} / \mathrm{p}-\mathrm{Si} / \mathrm{Al}$ heterostructure. Thin ZnO:MgO layers have been fabricated via the sol-gel technique with a precursor ratio of $1: 5$. Silicon wafers of KDB-4.5 type served as substrates, while the deposited films had an approximate thickness of 100 nm. Capacitance–voltage and current-voltage characteristics were recorded under optical excitation at wavelengths ranging from 278 to 1064 nm. The absolute spectral responsivity has been determined at both low and high bias voltages. It was observed that photoconductivity occurs under both polarities of the applied voltage. In the $\mathrm{C}-\mathrm{V}$ profiles, photoinduced charge accumulation has been revealed within the inversion region (+10 $\div+20 \mathrm{~V}$). The strongest variation of capacitance was detected under illumination at $\lambda=275 \mathrm{~nm}$. The analysis demonstrates that, with an increase of bias from 2.5 V up to 20 V, the UV sensitivity of the device rises significantly, reaching $12.2 \mathrm{~A} / \mathrm{W}$ at 278 nm. In the visible and infrared spectral ranges, the sensitivity remains between 2.5 and $5 \mathrm{~A} / \mathrm{W}$.

This study examines how varying niobium (Nb) concentrations influence the structural and ferroelectric characteristics of $\mathrm{SrBi}_{2}\left(\mathrm{Ta}_{1-\mathrm{x}} \mathrm{Nb}_{\mathrm{x}}\right)_{2} \mathrm{O}_{9}(\mathrm{SBTN})$ thin films. Raman spectroscopy analysis indicates notable shifts and alterations in spectral bands at higher Nb levels $(\mathrm{x}=0.5)$, attributed to distortions in the (Ta, Nb)O ${ }_{6}$ octahedral units and a decrease in lattice symmetry. These modifications lead to non-linear changes in the perovskite phase content and remanent polarization, with optimal performance observed at $\mathbf{x}=\mathbf{0. 1}-\mathbf{0. 2}$. The Landau-Devonshire model accurately predicts these behaviors, demonstrating that intermediate Nb doping boosts spontaneous polarization and stabilizes the perovskite phase. However, excessive $\mathbf{N b}(\mathbf{x}\gt 0.2)$ reduces perovskite formation and promotes grain coarsening, diminishing ferroelectric response. These findings highlight the potential of tailored $\mathbf{N b}$ doping in optimizing nanograined SBTN films for non-volatile ferroelectric RAM (NvFeRAM) applications.

The wettability of black silicon (b-Si) layers formed by reactive ion etching, metal-assisted chemical etching, and laser-induced etching has been studied. The wetting contact angles of the prepared samples with deionized water, glycerol, diiodomethane, and ethylene glycol were determined. It has been shown that the silicon oxide surface film and the enlargement area factor of b-Si layers have a significant influence on their wettability, varying from hydrophilic to hydrophobic properties.

The performance of FeRAM non-volatile cells including those on ferroelectric insulating layers requires full-scale development of the field effect at the semiconductor–dielectric interface. The recharging of electron traps concentrated in the buffer layer between the insulator and the wafer impedes the development of the field effect at the interface. A Si wafer has been hydrogen-saturated for suppressing the activity of electron traps in the buffer layer at the ferroelectric–silicon contact. The reference specimen has been another similar wafer not exposed to H2. High-frequency C–V curves of the metal–dielectric–semiconductor structures with Ba0.8Sr0.2TiO3 insulating layers deposited on both wafers have been measured. The capacities of the test specimens have proven to be low sensitive to hydrogen saturation of the wafers. This is accounted for by long-term heating of the silicon wafers at 500–600 °C during ferroelectric deposition. It has been proposed to implant large organic cations into the wafers in order to reduce the concentration of electron traps in the Ba0.8Sr0.2TiO3–Si buffer layers. Those organic cations can be 2–phenylethyl ammonium iodide, 4-chlorophenylethyl ammonium iodide and 4-fluorophenylethyl ammonium iodide which showed good results at passivation of high-performance metal–halogenide perovskite solar cells.

This paper presents the development of a technique for synthesizing ITO sol-gel films with embedded YAGG:Cr3+, Yb3+ nanocrystals that exhibit a long-lasting afterglow on the surface of a photoelectric solar cell. The properties of ITO layers for further application in optoelectronics and solar energy have been studied. The Pechini method provides the luminescence intensity of ITO films with YAGG:Cr3+, Yb3+ nanocrystals 4 times higher than the chemical deposition method. Solar cells with an additionally deposited ITO coating with YAGG:Cr3+, Yb3+ luminescent nanocrystals maintained a residual voltage of up to 0.51 V for 30–60 min.

Polycrystalline thin films ofstrontium bismuth tantalate SryBi2 + xTa2O9 with different Sr : Bi : Ta molar ratios are obtained by a sol–gel method. The formation of a phase with a perovskite structure is established. Phase transitions are confirmed by dielectric spectroscopy. In the mode of polarization switching spectroscopy, remnant piezoelectric hysteresis loops are obtained which confirm the ferroelectric nature of the synthesized SryBi2 + xTa2O9 films.

Исследована смачиваемость слоев черного кремния (b-Si), сформированных методами реактивного ионного травления, металл-стимулированного химического травления и лазерно-индуцированного травления. Определены краевые углы смачивания изготовленных образцов деионизованной водой, глицерином, дийодметаном и этиленгликолом. Показано, что поверхностная пленка окисла кремния и коэффициент увеличения площади слоев b-Si оказывают существенное влияние на их смачиваемость, варьируя от гидрофильных к гидрофобным свойствам. Հետազոտվել է ռեակտիվ իոնային խածատման, մետաղով խթանմամբ քիմիական խածատման և լազերային խածատման մեթոդներով ձևավորված սև սիլիցիումի (b-Si) շերտերի թրջելիությունը: Գնահատվել են պատրաստված նմուշների դեիոնացված ջրով, գլիցերինով, դիյոդմեթանով և էթիլենգլիկոլով թրջման հպակային անկյունները: Ցույց է տրվել, որ սիլիցիումի օքսիդի մակերևութային թաղանթը և b-Si շերտերի մակերեսի մեծացման գործակիցը զգալի ազդեցություն ունեն թրջելիության վրա՝ ապահովելով հիդրոֆիլայինից մինչև հիդրոֆոբային հատկություններ: The wettability of black silicon (b-Si) layers formed by reactive ion etching, metal-assisted chemical etching, and laser-induced etching has been studied. The wetting contact angles of the prepared samples with deionized water, glycerol, diiodomethane and ethylene glycol were determined. It has been shown that the silicon oxide surface film and the enlargement area factor of b-Si layers have a significant effect on their wettability, varying from hydrophilic to hydrophobic properties.

Polycrystalline thin films of bismuth-strontium tantalum SryBi2+xTa2O9 with different molar ratio Sr:Bi:Ta were obtained by sol-gel method. The formation of a phase with a perovskite structure has been established. Phase transitions have been confirmed by dielectric spectroscopy. In the mode of polarization switching spectroscopy, remnant piezoelectric hysteresis loops were obtained, which confirms the ferroelectric nature of the synthesized SryBi2+xTa2O9 films.

The results of a study of the optical properties of a black silicon (BS) layer passivated with ZnO films obtained by the sol-gel technique are presented. The BS layer was formed by the reactive ion etching process using an SF6/O2 plasma. The reflectance spectra of the BS/ZnO structures were simulated using the finite difference time domain method. In this simulation, the structure is considered a thick silicon substrate with regular near-surface straight circular nanocones uniformly coated with a thin ZnO film. The reflectance of the experimental samples was measured using a spectrometer with an integrating sphere. The ZnO sol-gel film, in addition to surface passivation of the BS layer, noticeably improves the reflectance in the entire spectral range necessary for the operation of a solar cell. BS/ZnO structures exhibit a low reflectivity in the wavelength range of 400–800 nm and at radiation incidence angles up to 50°. Thicker films are most preferred. Studies have shown that the simulation results are in good agreement with experimental data in the case of thin films. For structures with thick ZnO films, it is necessary to take into account the differences in the morphology of the model and real surfaces.

The photoelectric characteristics of sol-gel ZnOx:MgOx layers on an n-Si substrate, measured in the temperature range from 5 to 50 °C, has been analyzed. For photodetector applications, the current must flow across the ZnOx:MgOx/n-Si/InGa structure and it should operate in pre-avalanche or avalanche mode (U of the order of −20 V). A strong effect of temperature on the photoelectric characteristics has been established, associated with the inclusion in the current transfer of various local energy levels due to electrically active impurities and defects at the interface of the structure.

The influence of various parameters, such as annealing temperature and Nb content, on the structure and piezoelectric properties of thin-film structures based on the SBTN sol-gel layer are determined. The values of piezoresponse were investigated, and experiments on local polarization switching were carried out. Dependencies of the piezoelectric coefficients on the composition of the SBTN layer and the parameters of the sol-gel process were established.

This study provides the optimization of double-beam cutting of quartz plates through laser cleaving. Neural network simulation and the authors’ version of the modified genetic algorithm were used to determine the optimal processing parameters. Finite element calculations of temperature and thermoelastic stress fields were performed to create the training data array and the array data for testing neural networks. Neural networks and their training algorithms were implemented with the Keras library in Python. The optimal neural network architectures for approximating the maximum values of tensile stresses and temperature during laser cutting of quartz plates were determined. The genetic algorithm was used to find the optimal parameter values for quarts plate laser cutting process.

In this work, we have investigated the photocurrent and spectral sensitivity of the silicon/SrTiO3:xNb/perovskite structures. The sol–gel method carried out the deposition of undoped SrTiO3 layers as well as niobium-doped (SrTiO3:Nb) layers at atomic concentrations of 3 and 6% Nb. The perovskite layer, CH3NH3PbI3−xClx, has been deposited by the vacuum co-evaporation technique. The layers have been characterized by scanning electron microscopy and X-ray diffraction measurements. The volt–ampere characteristics and spectral sensitivity of the fabricated samples have been measured under illumination with selective wavelengths of 405, 450, 520, 660, 780, 808, 905, 980, and 1064 nm of laser diodes. We have shown that for different configurations of applied voltage between silicon, SrTiO3:xNb, and CH3NH3PbI3−xClx, the structures are photosensitive ones with a variation of photocurrent from microamperes to milliamperes depending on Nb concentration in SrTiO3, and the highest photocurrent and spectral sensitivity values are observed when a SrTiO3:Nb layer with 3 at.% of Nb is used. A possible application of the proposed structure with a SrTiO3:Nb layer for perovskite solar cells and photodetectors is being discussed.

The current paper uses neural network modeling and a genetic algorithm to determine the values of technological parameters that ensure effective laser cleaving of quartz glass when exposed to a laser beam with a wavelength equal to 10.6 µm and a refrigerant. Multi-criteria optimization of laser cleaving of quartz plates was performed according to the criteria of maximum tensile stresses and maximum processing speed.