Hydrogen Fluoride Research Articles

The impact of export controls on international trade: Evidence from the Japan–Korea trade dispute in semiconductor industry

In July 2019, the Japanese government announced export controls to South Korea of three chemical inputs essential in semiconductor production. This paper investigates the short- to middle-run effect of the Japan–Korea export controls on the trade patterns of the restricted and other related products of the semiconductor industry. The results show that the export controls caused a large decline in Japanese exports to South Korea of one of the three restricted inputs, hydrogen fluoride, but not in the other two restricted inputs, photoresist and fluorinated polyimide. Second, South Korea reallocated the sourcing of the restricted chemical inputs from Japan to other economies such as Belgium, the U.S., and Taiwan. Third, there was negative spillover effect on the South Korean imports of semiconductor manufacturing equipments, which is used complementarily with the restricted inputs in the semiconductor production. These results suggest a potential role of export controls in sourcing patterns and production relocation in the semiconductor industry.

Plasma simulation of HF plasma generated in dual-frequency chamber for high aspect ratio dielectric etching

For the 3D NAND memory hole with a high aspect ratio above 100, the etching process with hydrogen-fluoride (HF) contained plasmas has been proposed. We have developed a simulation model for gas-phase reactions that reproduces the HF plasma in experiments. The HF plasma was generated using a power supply of 100 MHz frequency, and electron and F densities were measured. The simulation model was constructed on the basis of the collision cross sections and reaction constants reported in the previous papers, and the F density in the simulation was calibrated by comparing it with that in the experiments. As a result of the plasma simulation, the densities of F and the electrons were determined to be 7.52 × 1016 m–3 and 8.50 × 1016 m–3, respectively. Taking into consideration the errors in the experiment, we considered that the simulation model is able to reproduce the experimental HF plasma well.

Adsorbtive removal of HF toxic gas via tinsulfide monolayer modification: A molecular perspective

Hydrofluoric Acid (HF) is considered one of the most hazardous chemicals used in industrial plants. Even small exposures to HF can have fatal consequences if not promptly and properly treated. Various research teams have presented numerous substances with the objective of capturing or detecting toxic HF gas. In this study, we explore the impact of HF gas on a single layer of SnS by employing density functional theory (DFT). The interaction nature between the gas molecule and the adsorbent is elucidated by analyzing the related adsorption energy, electronic structure properties and differential charge transfer. The findings indicate that HF is physically adsorbed on the pristine SnS with an adsorption energy value of −0.63 eV. By introducing a Sn mono vacancy defect, the modification of SnS enhances the adsorption energy to −1.26 eV, resulting in a chemisorption process. Molecular fluorine (F2) was discovered to undergo a barrierless reaction with SnS, resulting in the formation of fluorine-substituted SnS. It has been discovered that the substitution of fluorine atoms enhances the reactivity of SnS towards hydro-gen fluoride gas. The adsorption potential of the studied structures towards HF gas was determined to be in the following order: F2SnS > VSn–SnS > VS-SnS ∼ SnS. The current study is anticipated to offer new molecular insights that could lead to the creation of innovative devices for detecting or eliminating HF toxic gas from a specific atmosphere.

CATALYTIC REDUCTIVE HYDRODEFLUORINATION OF 1,1-DIFLUORONAPHTHALEN-2(1H)-ONE

An optimised method of 1,1-difluoronaphthalen-2(1H)-one hydrodefluorination leading to the formation of fluoronaphthol under mild conditions is proposed. The palladium-catalysed process is shown to involve carbonyl reduction followed by subsequent hydrogen fluoride elimination. The structure of the intermediate product and the effect of catalyst support material on hydrodefluorination selectivity have been determined.

Effect of a novel low-concentration hydrogen peroxide bleaching gel containing nano-sized sodium trimetaphosphate and fluoride

ObjectivesTo evaluate in vitro the effects of nano-sized sodium trimetaphosphate (TMPnano) and sodium fluoride (F) added to a 17.5 % hydrogen peroxide (H2O2) bleaching gel on the color change, enamel mechanical and morphological properties, and H2O2 transamelodentinal diffusion. Materials and MethodsBovine enamel/dentin discs (n = 180) were divided according to the bleaching gel: 17.5 % H2O2 (17.5 % HP); 17.5 % H2O2 + 0.1 % F (HP/F); 17.5 % H2O2 + 1 % TMPnano (HP/TMPnano); 17.5 % H2O2 + 0.1 % F + 1 % TMPnano (HP/F/TMPnano) and 35 % H2O2 (35 % HP). The gels were applied for 40 min on three sessions, each session spaced 7 days apart. The total color change (ΔE*ab) according to the Commission Internationale de l'Eclairage (CIE) L*a*b* color change measured by CIEDE2000 (ΔE00), whitening index (ΔWID), surface hardness (SH), surface roughness (Ra), cross-sectional hardness (ΔKHN), and transamelodentinal diffusion were assessed. Enamel surfaces were examined using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDS) analysis. The data were analyzed using ANOVA, followed by the Student-Newman-Keuls test (p < 0.05). ResultsΔE*ab, ΔE00, and ΔWID values were comparable among the gels that produced a bleaching effect post-treatment (p < 0.001). The HP/F/TMPnano group exhibited lower mineral loss (SH and ΔKHN), Ra, and H2O2 diffusion compared to the 17.5 % HP and 35 % HP groups, which had the highest values (p < 0.001). SEM/EDS analysis revealed surface changes in all bleached groups, though these changes were less pronounced with F/TMPnano. ConclusionsThe 17.5 % HP gel containing F/TMPnano maintains the bleaching effect while reducing enamel demineralization, roughness, H2O2 diffusion, and enamel morphological changes. Clinical RelevanceLow-Concentration H2O2 bleaching gel containing F/TMPnano can be used as a novel approach to enhance safety and maintain the performance of aesthetic effects.

Thallium-Fluorides Revisited: Crystal Chemistry of TlHF2, Tl2[MF6]·2TlF, and Tl2[MF6]·TlCl (M = Si and Ge).

Although the formation of thallium hydrogen fluorides TlHxFx+1 (x = 1, 1.5, 2, 3, 5, 6.5, and 7) from TlF and HF was reported in the 1970s, little is known about the corresponding crystal structures. To shed light on the crystal chemistry of the thallium fluorides, we reinvestigated the structure of α-TlHF2, which was obtained by crystallization of TlF from 50% HF at room temperature. We disclose that β-TlHF2 is isostructural with α-MHF2 (M = K, Rb, and Cs), γ-TlHF2 is isostructural with β-MHF2 (M = K and Rb), whereas α-TlHF2 crystallizes in an unusual structure type. During the reaction of TlHF2 with the glass of the microscope slide, crystals of the previously unknown compound Tl2[SiF6]·2TlF were formed. We disclose that the related Tl2[GeF6]·2TlF can be obtained by the crystallization of stoichiometric amounts of Tl2[GeF6] with TlF from water at room temperature. The crystal structures of α-TlHF2, Tl2[SiF6]·2TlF, Tl2[SiF6]·TlCl, Tl2[GeF6]·2TlF, Tl2[GeF6]·TlCl, and Tl2[GeF6] were determined by single-crystal X-ray diffraction analysis. The crystal structures of α-TlF and Tl2[SiF6]·xTlF (x = 0, 1) were redetermined at low temperatures.

Ultrathin ZrO2 thickness control on TiO2/ZrO2 core/shell nanoparticles using ZrO2 atomic layer deposition and etching

Atomic layer deposition (ALD) and atomic layer etching (ALE) techniques were used to control the ZrO2 shell thickness on TiO2/ZrO2 core/shell nanoparticles. ALD and ALE were performed at 200 °C while the nanoparticles were agitated using a rotary reactor. To increase the ZrO2 shell thickness, ZrO2 ALD films were deposited using sequential exposures of tetrakis(dimethylamino) zirconium and H2O. Ex situ analysis using transmission electron microscopy (TEM) observed the growth of the ZrO2 shells. The ZrO2 ALD led to more spherical ZrO2 shells on the crystalline and irregular TiO2 cores. The ZrO2 ALD on the nanoparticles had a growth rate of 0.9 ± 0.1 Å/cycle. Tunable ZrO2 coatings were observed with thicknesses ranging from 5.9 to 27.1 nm after 240 ZrO2 ALD cycles. To demonstrate the decrease in the ZrO2 shell thickness, the ZrO2 film was then etched using sequential hydrogen fluoride (HF) and TiCl4 exposures. Quadrupole mass spectrometry experiments performed in a separate reactor identified the volatile products during ZrO2 ALE. H2O was monitored during HF exposures, and ZrCl4 etch products and TiFxCly ligand-exchange products were observed during TiCl4 exposures. Ex situ TEM studies revealed that the ZrO2 shells remained spherical during ZrO2 ALE. The ZrO2 ALE on the nanoparticles had an etch rate of 6.5 ± 0.2 Å/cycle. Tunable ZrO2 coatings were produced from 27.1 down to 7.6 nm using 30 ZrO2 ALE cycles. This study demonstrated that ZrO2 ALD and ZrO2 ALE can control the thickness of ZrO2 shells on TiO2/ZrO2 core/shell nanoparticles without inducing nanoparticle agglomeration.

Revealing the interfacial chemistry of silicon anodes with polysiloxane electrolyte additives

Silicon (Si) anodes are promising in lithium-ion batteries owing to their high specific capacity and suitable voltage platform. However, particle volume expansion (>300 %) and the continuous consumption of Li+ to form new interfacial layers result in poor cycle performance. We report a sustainable low-cost Si material derived from photovoltaic cutting waste, showing a high initial Coulombic efficiency (86.9 %). The cycle stability of Si/graphite is enhanced in terms of a 38 % capacity retention increase in the presence of vinyl-terminated polydimethylsiloxane (Vi-PDMS) additive. The C = C bond in Vi-PDMS plays a role in reacting with hydrogen fluoride (HF) by-products to prevent the side reaction between HF and solvent. The decomposed macromolecule Si-containing Li salt serves as a part of the solid electrolyte interphase film and has low interface resistance. This formed interphase layer effectively mitigates stress concentration at the contact surface between silicon particles and the current collector caused by expansion forces.

Efficient extraction of hydrogen fluoride using hollow fiber membrane contactors with the aid of active‐learning

AbstractThis study presents a sustainable approach to extracting hydrogen fluoride (HF) from wastewater using hollow fiber membrane contactors. HF, a widely used yet hazardous chemical, requires efficient separation techniques due to its environmental and health concerns. Our research compared two operational modes, vacuum mode and liquid–liquid extraction mode, revealing the latter as more efficient for HF separation. Notably, this study introduces a novel aspect by employing a data‐driven decision‐making method, Bayesian optimization (BO) for process optimization of the liquid–liquid extraction mode, aiming to maximize HF removal efficiency at low experimental costs. Subsequent validation through a 96‐h experimental run confirms the suitability of the optimized conditions for industrial applications. This study not only demonstrates an efficient HF separation process using hollow fiber membrane contactors but also establishes a new standard for complex industrial process optimization.

Effect of Silyl Ether Bulk on Excited-State Intramolecular Proton Transfer-Based Sensing of Extant Hydrogen Fluoride for G-Series Nerve Agent Detection.

Luminescence-based sensing provides a method for the rapid detection of nerve agents. Previous approaches have generally focused on sensing materials containing a nucleophilic group that can react with the electrophilic phosphorus atom found in nerve agents. Herein we report an alternative approach for the detection of phosphonofluoridate-based G-series nerve agents that utilizes the fact they contain hydrogen fluoride. We have developed silylated sensing materials based on an excited-state intramolecular proton transfer (ESIPT) reporter compound, 2-[benzo[d]thiazol-2-yl]phenol. Thin films of differently silylated 2-[benzo[d]thiazol-2-yl]phenol were found to react with the hydrogen fluoride found in di-iso-propyl fluorophosphate (DFP), a simulant of sarin (G-series nerve agent), and turn on the ESIPT emission of the reporter compound. The use of the ESIPT emission reduced the impact of background fluorescence and improved the sensitivity of the detection. The effectiveness of the approach was dependent on the stability of the silyl protecting group used, with the least sterically hindered (trimethylsilyl) found to be too unstable to the ambient environment while the most sterically hindered, e.g., tri-iso-propylsilyl and tert-butyldiphenylsilyl were found to be insufficiently reactive to be useful in a real detection scenario. The sensing material composed of the tert-butyl dimethylsilyl protected 2-[benzo[d]thiazol-2-yl]phenol was found to have the best balance between stability under ambient conditions, and reactivity and selectivity to hydrogen fluoride. In a 3s exposure, it could detect hydrogen fluoride down to a concentration of around 23 ppm in DFP with 99% purity.

Photoionization of hydrogen halides using the R-matrix method

Abstract In this study, we use the UK Molecular R-matrix (UKRMol) codes in the close-coupling approximation to examine the photoionization of hydrogen halides (hydrogen fluoride, hydrogen chloride, and hydrogen bromide). This article reports the total and partial photoionization cross sections for the X2Π, A2Σ+, and B2Σ+ ionic states of these halides. The calculated cross sections are compared with the available literature, which does not accurately represent the effective cross sections near the threshold region, which is dominated by the Rydberg series autoionization resonances converging to the A2Σ+ ionic state. There seems to have been minimal effort to investigate the Rydberg-bound states of these halides. Meanwhile, the R-matrix approaches have traditionally excelled at characterizing such studies. This indicates the effectiveness of this method for molecular photoionization as well as for understanding the resonant contribution to the photoionization cross sections. The detailed cross sections calculated comprise the complex autoionizing resonance structures capable of significantly contributing to the computations of total photoionization rates, which are necessary to maintain a steady state of ionization in astrophysical plasmas. Comparisons with the experimental measurements and the theoretical data generally show reasonable agreement across the reported energy range.

Safety and behavior of implantable electronic devices during cremation

BackgroundThe current standard of practice for cremating patients with cardiac implantable electronic devices (CIEDs) is surgical explantation before cremation to mitigate the risk of device explosion. This surgery may conflict with patient or family beliefs, whereas cremation of CIEDs may create occupational hazards. ObjectiveThis study sought to establish an ex vivo model for screening CIED behavior during cremation. MethodsSeven CIEDs underwent testing including projectile/sound testing, impact testing, and gas analysis. In the projectile test, devices were heated until thermal failure (explosion) and filmed with a high-speed camera and microphone. For impact testing, brick structures were built to assess damage after explosion. Gas chromatography–mass spectrometry identified released gases. Findings were compared with occupational health standards, where available. ResultsThe implantable loop recorder and leadless pacemaker produced minimal kinetic energy and impact risk with thermal failure. The remaining devices demonstrated explosive disintegration at thermal temperatures <500°C. The pacemakers and implantable cardiac defibrillators produced sound levels >120 dB and resulted in damage to brick structures. Small quantities of benzene and hydrogen fluoride were produced but at quantities within acceptable occupational exposure limits in a cremation chamber. ConclusionAll tested CIEDs experienced explosion at temperatures below crematorium standards. The smallest devices produced minimal risk of damage or injury, suggesting that they may safely remain in situ during cremation, whereas the larger devices produced more kinetic energy, testing chamber damage, and louder explosions, suggesting potential risk with cremation. Cadaveric testing in full-sized cremation chambers is required to determine real-world risk.

Abundances of trace constituents in Jupiter’s atmosphere inferred from Herschel/PACS observations

Context. On October 31, 2009, the Photodetector Array Camera and Spectrometer (PACS) on board the Herschel Space Observatory observed far-infrared spectra of Jupiter in the wavelength range between 50 and 220 µm as part of the program “Water and Related Chemistry in the Solar System”. The spectra have an effective spectral resolution between 900 and 3500, depending on the wavelength and grating order. Aims. We investigate the disk-averaged chemical composition of Jupiter’s atmosphere as a function of height using these observations. Methods. We used the Planetary Spectrum Generator and the least-squares fitting technique to infer the abundances of trace constituents. Results. The PACS data include numerous spectral lines attributable to ammonia (NH3), methane (CH4), phosphine (PH3), water (H2O), and deuterated hydrogen (HD) in the Jovian atmosphere and probe the chemical composition from p ~ 275 mbar to p ~ 900 mbar. From the observations, we infer an ammonia abundance profile that decreases from a mole fraction of (1.7 ± 0.8) × 10−4 at p ~ 900 mbar to (1.7 ± 0.9) × 10−8 at p ~ 275 mbar, following a fractional scale height of about 0.114. For phosphine, we find a mole fraction of (7.2 ± 1.2) × 10−7 at pressures higher than (550 ± 100) mbar and a decrease of its abundance at lower pressures following a fractional scale height of (0.09 ± 0.02). Our analysis delivers a methane mole fraction of (1.49 ± 0.09) × 10−3. Analyzing the HD R(0) line at 112.1 µm yields a new measurement of Jupiter’s D/H ratio, D/H = (1.5 ± 0.6) × 10−5. Finally, the PACS data allow us to put the most stringent 3σ upper limits yet on the mole fractions of hydrogen halides in the Jovian troposphere. These new upper limits are &lt;1.1 × 10−11 for hydrogen fluoride (HF), &lt;6.0 × 10−11 for hydrogen chloride (HCl), &lt;2.3 × 10−10 for hydrogen bromide (HBr) and &lt;1.2 × 10−9 for hydrogen iodide (HI) and support the proposed condensation of hydrogen halides into ammonium halide salts in the Jovian troposphere.

Chemical etching of CAD-CAM glass-ceramic-based materials using fluoride solutions for bonding pretreatment.

The surface treatment of glass-ceramic-based materials, namely, lithium disilicate glass (IPS e.max CAD), feldspar porcelain (VITABLOCS Mark II), and a polymer-infiltrated ceramic network (VITA ENAMIC), using aqueous fluoride solutions and their influence on luting agent bonding were investigated. Six experimental aqueous fluoride solutions were applied to these materials, and their effects were assessed by surface topological analysis. The obtained results were compared using non-parametric statistical analyses. Ammonium hydrogen fluoride (AHF) etchant demonstrated the greatest etching effect. Subsequent experiments focused on evaluating different concentrations of the AHF etchant for the bonding pretreatment of glass-ceramic-based materials with a luting agent (PANAVIA V5). AHF, particularly at concentrations above 5 wt%, effectively roughened the surfaces of the materials and improved the bonding performance. Notably, AHF at a concentration of 30 wt% exhibited a more pronounced effect on both etching and bonding capabilities compared to hydrofluoric acid.

The ESO SupJup Survey II. The 12C/13C isotope ratios of three young brown dwarfs with CRIRES+

Young brown dwarfs exhibit atmospheric characteristics similar to those of super-Jupiters, providing a unique opportunity to study planetary atmospheres. Atmospheric retrievals of high-resolution spectra reveal detailed properties of these objects, with elemental and isotopic ratios offering insights into their formation history. The ESO SupJup Survey, utilising CRIRES$^+$ on the Very Large Telescope, aims to assess the role of as a formation tracer. We present observations of three young brown dwarfs: 2MASS J12003792-7845082, TWA 28, and 2MASS J08561384-1342242. Our goal is to constrain their chemical compositions, thermal profiles, surface gravities, spin rotations, and Cratio. We conducted atmospheric retrievals of CRIRES$^+$ K-band spectra, coupling the radiative transfer code petitRADTRANS with the Bayesian inference algorithm MultiNest The retrievals provide a detailed characterisation of the atmospheres of the three objects. We report the volume mixing ratios of the main molecular and atomic species: HF, Na, Ca, and Ti, including the novel detection of hydrogen fluoride (HF) in the atmosphere of a brown dwarf. We determine values of $ and $79^ $ in the atmospheres of TWA 28 and J0856, respectively, with strong significance ($&gt;3 We also report tentative evidence ($ of in J1200, at $. Additionally, we detect at moderate significance in J0856 (3.3sigma ) and TWA 28 (2.1sigma ). The retrieved thermal profiles are consistent with hot atmospheres ($2300-2600$ K) with low surface gravities and slow spins, as expected for young objects. The measured carbon isotope ratios are consistent among the three objects and show no significant deviation from that of the local interstellar medium, suggesting a fragmentation-based formation mechanism similar to star formation. The tentative detection of in two objects of our sample highlights the potential of high-resolution spectroscopy to probe additional isotope ratios, such as O in the atmospheres of brown dwarfs and super-Jupiters.

Accelerating Density Matrix Embedding with Stochastic Density Fitting Theory: An Application to Hydrogen Bonded Clusters.

In this work, we demonstrate how using semistochastic density fitting (ss-DF) can accelerate self-consistent density matrix embedding theory (DMET) calculations by reducing the number of auxiliary orbitals in the three-indexed DF integrals. This reduction results in significant time savings when building the Hartree-Fock (HF) Coulomb and Exchange Matrices and in transforming integrals from the atomic orbital (AO) basis to the embedding orbital (EO) basis. We apply ss-DF to a range of hydrogen-bonded clusters to showcase its effectiveness. First, we examine how the amount of deterministic space impacts the quality of the calculation in a (H2O)10 cluster. Next, we test the computational efficiency of ss-DF compared to deterministic DF (d-DF) in water clusters containing 6-30 water molecules using a triple-ζ basis set. Finally, we perform numerical structural optimizations on water and hydrogen fluoride clusters, revealing that DMET can recover weak interactions using a back-transformed energy formula. This work demonstrates the potential of using stochastic resolution of identity in quantum embedding theories and highlights its capability to recover weak interactions effectively.

The Effect of Surface Treatments on the Retentive Strengths of Crowns Fabricated From Polymethylmethacrylate (PMMA) Reinforced With Graphene Nanoparticles After Thermocycling: An In Vitro Study.

The study aimsto assess the effect of surface treatments by chemical agents on the retentive strengths of crowns fabricated from polymethylmethacrylate (PMMA)reinforced with graphene nanoparticles adhesively bonded to abutments after thermocycling. In vitro comparative study. This study is composed of four groups - one control, one treated with 99% pure etchant acetone solution, one treated with 15 wt% potassium hydrogen fluoride solution, and the last group treated with a combination of both solutions. The results showed that the mean load in Group A is 228.46±3.16, Group B is 252.57±7.14, Group C is 184.51±6.61, and Group D is 211.03±2.54. The mean score is highest for Group B followed by Group A and Group D, and it is least for Group C. One-way analysis of variance (ANOVA) detected highly significant differences (p<0.01) among the four groups. It can be concluded that acetone is the best chemical etchant solution forcrowns fabricated from G-CAMdiscs (Graphenano Dental, Graphenano Nanotechnologies, Spain).

The Fate of Fluorine Post Per- and Polyfluoroalkyl Substances Destruction during the Thermal Treatment of Biosolids: A Thermodynamic Study

Per- and polyfluoroalkyl substances (PFAS) are a group of fluorinated synthetic chemicals that are highly recalcitrant, toxic, and bio-accumulative and have been detected in biosolids worldwide, posing potential risks to humans and the environment. Recent studies suggest that the organic C-F bond in PFAS can be destructed and potentially mineralised into inorganic fluorides during thermal treatment. This study focuses on thermodynamic equilibrium investigations and the fate of fluorine compounds post-PFAS destruction during biosolid thermal treatment. The results indicate that gas-phase fluorine compounds are mainly hydrogen fluoride (HF) and alkali fluorides, whereas solid-phase fluorine compounds include alkaline earth fluorides and their spinels. High moisture and oxygen content in the volatiles increased the concentration of HF in the gas phase. However, adding minerals reduced the emission of HF in the gas phase significantly and enhanced the capture of fluorine as CaF2 spinel in the solid phase. This study also investigates the effect of feedstock composition on the fate of fluorine. High ash content and low volatile matter in the feedstock reduced HF gas emissions and increased fluorine capture in the solid product. The findings of this work are useful in designing thermal systems with optimised operating conditions for minimising the release of fluorinated species during the thermal treatment of PFAS-containing biosolids.

Na[GeF5]·2HF: the first quarternary phase in the H-Na-Ge-F system.

The structure of cis- or trans-bridged [GeF5]- anionic chains have been investigated [Mallouk et al. (1984). Inorg. Chem. 23, 3160-3166] showing the first crystal structures of μ-F-bridged pentafluorogermanates. Herein, we report the second crystal structure of trans-pentafluorogermanate anions present in the crystal structure of sodium trans-pentafluorogermanate(IV) bis(hydrogen fluoride), Na[GeF5]·2HF. The crystal structure [orthorhombic Pca21, a= 12.3786 (3), b= 7.2189 (2), c= 11.4969 (3) Å and Z= 8] is built up from infinite chains of trans-linked [GeF6]2- octahedra, extending along the b axis and spanning a network of pentagonal bipyramidal distorted Na-centred polyhedra. These [NaF7] polyhedra are linked in a trans-edge fashion via hydrogen fluoride molecules, in analogy to already known sodium hydrogen fluorides and potassium hydrogen fluorides.

SYNTHESIS AND CHARACTERISTICS OF ZnS NANOWIRES

The creation of a nanoporous silicon dioxide layer in the a-SiO2/Si-n structure was accomplished by irradiation with xenon ions at a cyclotron and then chemical etching with an aqueous solution of hydrogen fluoride with the addition of palladium. The truncated cone-shaped nanopores had diameters ranging from 486 to 509 nm. Then ZnS nanowires synthesized by electrochemical deposition (ECD) method, depending on the voltage at the electrodes of the electrolytic cell and as a result zinc sulfide nanowires with cubic structure and spatial symmetry group F-43m (216) were obtained. The sample is characterized by (111), (200), (220), (331) (311) planes, respectively, which is in good agreement with the cubic phase of ZnS. The charge-voltage characteristics (CVC) of ZnS showed that an n-type conductivity semiconductor was formed. Measurements of the photoluminescence (PL) spectra of ZnS were recorded on a CM 2203 spectrofluorimeter. The PL spectra were recorded in the range of 250 nm to 450 nm at room temperature. The PL spectra of the precipitated precipitates reveals emission in a wide UV-visible spectral range. It can be seen that the luminescence spectra have quite complex components and can be divided into five Gaussian curves. As can be seen the FL spectrum of the deposited ZnS consists of bands at 3.15 eV, 3.3 eV, 3.4 eV, 3.55 eV and 3.73 eV. Also analyzing the spectra energy dispersive analysis showed that the ZnS nanoproofs consist of Zn – 42.5% and S – 57.5%.