Secondary Ion Mass Spectrometry Analysis Research Articles

Matrix Corrected SIMS In Situ Oxygen Isotope Analyses of Marine Shell Aragonite for High Resolution Seawater Temperature Reconstructions

AbstractMarine shells incorporate oxygen isotope signatures during growth, creating valuable records of seawater temperature and marine oxygen isotopic compositions. Secondary ion mass spectrometry (SIMS) measures these compositions in situ at finer length‐scales than traditional stable isotope analyses. However, determining oxygen isotope ratios in aragonite, the most common shell mineral, is hampered by a lack of ideal reference materials, limiting the accuracy of SIMS‐based seawater temperature reconstructions. Here, we tested the capability of SIMS to produce seawater temperature reconstructions despite the matrix calibration challenges associated with aragonite. We cultured Anadara trapezia bivalves at four controlled seawater temperatures (13–28°C) and used strontium labeling to mark the start of the temperature‐controlled shell increment, allowing for more spatially precise SIMS analysis. An improved matrix calibration was developed to ensure more accurate bio‐aragonite analyses that addressed matrix differences between the pure abiotic reference materials and the bio‐aragonite samples with intricate mineral‐organic architectures and distinct minor and trace element compositions. We regressed SIMS‐IRMS biases of abiotic and biogenic aragonites that account for their systematic differences in major, minor, and trace elements, allowing for more accurate SIMS analyses of the temperature‐controlled shell increment. The thorough matrix calibration allowed us to provide a SIMS‐based seawater‐corrected oxygen isotope thermometer of T(°C) = 23.05 ± 0.36 − 4.48 · (δ18Oaragonite [‰ VPDB] − δ18Oseawater [‰ VSMOW] ± 0.25) and 103lnαaragonite‐seawater = (17.78 ± 0.88) · 103/T (K) − (29.44 ± 2.40) that agrees with existing aragonitic IRMS‐based thermometer relationships and improves the applicability of SIMS‐based paleo‐environmental reconstructions of marine bio‐aragonites.

SIMS and Numerical Analysis of Asymmetrical Out-Diffusion of Hydrogen and Carbon in CdxZn1-xO:Eu Multilayer.

This study employs secondary ion mass spectrometry (SIMS) to investigate the diffusion behavior of hydrogen and carbon in a CdxZn1-xO:Eu multilayer at different annealing temperatures (500-900 °C). The SIMS results reveal a significant out-diffusion of these elements toward the surface and diffusion to the interface region. The diffusion flow rates are asymmetric and favor the interface direction. The depth profiles of diffused elements are fitted using the forward timecentered space (FTCS) iteration method. The activation energies are determined to be 0.35 ± 0.06 eV for hydrogen and 0.33 ± 0.09 eV for carbon, suggesting an interstitial mechanism in CdxZn1-xO. The results indicate that increasing the annealing temperatures leads to a significant decrease in impurity concentrations.

New Insights on the Burst Release Kinetics of Spray-Dried PLGA Microspheres.

Spray drying is one of the leading manufacturing methods for active pharmaceutical ingredients (APIs) owing to its rapid, single-step, and cost-effective nature. It also has the capacity to generate microspheres capable of controlled release of APIs including biomolecules and vaccines. However, one of the key challenges of spray-dried formulations especially with poly(lactic-co-glycolic acid) (PLGA)-based controlled-release injectables is burst release, where a significant fraction of the API is released prematurely within a short period of time following administration, leading to detrimental impact on the performance and quality of end products. This study uses a model API, bovine serum albumin (BSA) protein, to identify the sources of burst release that may affect the kinetics and performance of long-acting injectable microsphere formulations. Spray-dried microspheres with various formulations (i.e., variable BSA/PLGA ratios) were characterized in terms of their morphology, particle size, surface area, thermal properties, moisture content, as well as chemical compositions and their distributions to investigate the impact of spray drying on the burst release phenomenon. The results suggest that a relatively high initial release (85%) observed is mainly attributed to the protein distribution close to the particle surface. Morphology analysis provided evidence that the microspheres retained their spherical structure during the burst release phase. X-ray photoelectron spectroscopy, hard X-ray photoelectron spectroscopy, and argon cluster sputtering-assisted time-of-flight secondary ion mass spectrometry analysis suggest an enrichment of PLGA on particle surfaces with buried BSA protein. The statistically significant difference in particle size and surface area between three different formulations may be responsible for an initial variation in release but did not seem to alter the overall burst release profile. Considering the suggested source of burst release, the two-fluid spray-drying method, characterized by a single liquid feed delivering a preprepared emulsion, generated matrix-type microspheres with a surface layer of PLGA, as evidenced by surface analysis. The PLGA surface layer proved to be prone to degradation and pore formation, allowing for faster diffusion of BSA out of the microspheres, resulting in a burst release. Increasing the polymer concentration did not seem to halt this process.

Investigating the Impact of Hydrogen Bonding on Silicon Nitride (SiNx) Film

The deposition of amorphous hydrogenated silicon nitride (a‐SiNx:H) via plasma‐enhanced chemical vapor deposition is critical for optimizing the performance of crystalline silicon (c‐Si) solar cells. This study investigates the impact of varying gas ratios (GR = NH3/SiH4) on the optical and physical properties of deposited SiNx films. Results show that the refractive index (RI) ranges from 1.8 to 2.3 with changing gas compositions. Fourier transform infrared Spectroscopy reveals shifts in [SiNH] and [SiH] stretching modes, indicating changes in hydrogen passivation and nitrogen incorporation. Hydrogen bonding densities of [SiH] and [SiNH] correlate positively with the RI. For example, the hydrogen bonding density [NH] ranges from 4.53 × 1023 to 6.32 × 1023 cm−3 for [SiNH] bonds while [Si‐H] varies from 6.93 × 1023 to 1.06 × 1024 cm−3. Secondary ion mass spectrometry (SIMS) analysis shows stable hydrogen intensity, contrasting with a decrease in nitrogenhydrogen bonds. These findings highlight the key role of hydrogen bonding in determining SiNx film properties, with significant implications for semiconductor and photovoltaic applications.

Effects of Hydrogen Dissociation During Gas Flooding on Formation of Metal Hydride Cluster Ions in Secondary Ion Mass Spectrometry.

The application of hydrogen flooding was recently shown to be a simple and effective approach for improved layer differentiation and interface determination during secondary ion mass spectrometry (SIMS) depth profiling of thin films, as well as an approach with potential in the field of quantitative SIMS analyses. To study the effects of hydrogen further, flooding of H2 molecules was compared to reactions with atomic H on samples of pure metals and their alloys. H2 was introduced into the analytical chamber via a capillary, which was heated to approximately 2200 K to achieve dissociation. Dissociation of H2 up to 30% resulted in a significant increase in the intensity of the metal hydride cluster secondary ions originating from the metallic samples. Comparison of the time scales of possible processes provided insight into the mechanism of hydride cluster secondary ion formation. Cluster ions presumably form during the recombination of the atoms and molecules from the sample and atoms and molecules adsorbed from the gas. This process occurs on the surface or just above it during the sputtering process. These findings coincide with those of previous mechanistic and computational studies.

Efficient mass manufacturing of high-density, ultra-low-loss Si3N4 photonic integrated circuits

Silicon nitride (Si3N4) photonic integrated circuits (PICs) offer significant advantages over traditional silicon photonics, including low loss and superior power handling at optical communication wavelength bands. To facilitate high-density integration and effective nonlinearity, the use of thick, stoichiometric Si3N4 films is crucial. However, when using low-pressure chemical vapor deposition (LPCVD) to achieve high optical material transparency, Si3N4 films exhibit large tensile stress on the order of GPa, leading to wafer cracking that challenges mass production. Methods for crack prevention are therefore essential. The photonic Damascene process has addressed this issue, attaining record low-loss Si3N4 PICs, but it lacks control of the waveguide height, leading to large random variations of waveguide dispersion and unpredictable spectrum responses of critical functional devices such as optical couplers. Conversely, subtractive processes achieve better dimension control but rely on techniques unsuitable for large-scale production. To date, an outstanding challenge is to attain both lithographic precision and ultra-low loss in high-confinement Si3N4 PICs that are compatible with large-scale foundry manufacturing. Here, we present a single-step deposited, DUV-based subtractive method for producing wafer-scale ultra-low-loss Si3N4 PICs that harmonize these necessities. By employing deep etching of densely distributed, interconnected trenches into the substrate, we effectively mitigate the tensile stress in the Si3N4 layer, enabling direct deposition of thick films without cracking and substantially prolonged storage duration. A secondary ion mass spectrometry (SIMS) analysis reveals that these deep trenches simultaneously serve as gettering centers for metal impurities, in particular copper, thereby reducing the absorption loss in Si3N4 waveguides. Lastly, we identify ultraviolet (UV)-radiation-induced damage that can be remedied through a rapid thermal annealing. Collectively, we develop ultra-low-loss Si3N4 microresonators and 0.5-m-long spiral waveguides with losses down to 1.4 dB/m at 1550 nm with high production yield. This work addresses the long-standing challenges toward scalable and cost-effective production of tightly confined, low-loss Si3N4 PICs as used for quantum photonics, large-scale linear and nonlinear photonics, photonic computing, and narrow-linewidth lasers.

The Role of Hydrogen in ReRAM.

Previous research on transistor gate oxides reveals a clear link between hydrogen content and oxide breakdown. This has implications for redox-based resistive random access memory (ReRAM) devices, which exploit soft, reversible, dielectric breakdown, as hydrogen is often not considered in modeling or measured experimentally. Here quantitative measurements, corroborated across multiple techniques are reported, that reveal ReRAM devices, whether manufactured in a university setting or research foundry, contain concentrations of hydrogen at levels likely to impact resistance switching behavior. To the knowledge this is the first empirical measurement depth profiling hydrogen concentration through a ReRAM device. Applying a recently-developed Secondary Ion Mass Spectrometry analysis technique enables to measure hydrogen diffusion across the interfaces of SiOx ReRAM devices as a result of operation. These techniques can be applied to a broad range of devices to further understand ReRAM operation. Careful control of temperatures, precursors, and exposure to ambient during fabrication should limit hydrogen concentration. Additionally, using thin oxynitride or TiO2 capping layers should prevent diffusion of hydrogen and other contaminants into devices during operation. Applying these principles to ReRAM devices will enable considerable, informed, improvements in performance.

Determining the carbon detection limit with magnetic sector dynamic secondary ion mass spectrometry (SIMS)

Dynamic SIMS is often used to evaluate the concentration of impurities in solids because of its high sensitivity, depth profiling capabilities, good depth resolution, and high throughput. Continuous ion beam sputtering with a high-density primary beam provides high sensitivity and reduces the background contribution from residual gases within the analytical chamber. Dynamic SIMS experiments performed with several magnetic sector instruments using various sputtering rate conditions demonstrated a slow decrease of the carbon detection limit with the increase of sputtering rate (SR), when it was varied by changing the sputtering beam density. The dependence data, within the scatter limits, can be fit by a power function of SR with the exponent of about −1/2. The observed detection-limit-dependence curve is common for magnetic sector SIMS instruments, owing to contamination and the design of the analytical chamber. The depth resolution of light-element SIMS analysis (except for oxygen) performed using Cs+ sputtering is limited and cannot be improved by reducing the impact energy of the sputtering beam. A segregation-type depth profile with a long trailing edge was observed in the B, C, and N depth profiles when Cs+ sputtering was employed under ultra-high vacuum conditions. This effect is plausibly associated with preferential sputtering owing to the difference in the surface binding energy, along with the large difference in the mass of the interacting atoms within the collision cascade during sputtering. The depth resolution improved with surface oxidation when Cs + sputtering was combined with backfilling of the analytical chamber using O2. The analytical chamber backfilled with oxygen can be sufficiently replaced with a very low-impact energy-focused oxygen beam, enabling simultaneous oxygen and cesium co-sputtering SIMS analysis. The practical feasibility of using a co-sputtering with focused Cs+ and O2+ sputtering beams to achieve a high depth-resolution for carbon analysis under ultrahigh vacuum conditions was demonstrated.

Exploring the Optimal Binder Content in Composite Electrodes for Sulfide-Based All-Solid-State Lithium-Ion Batteries

All-solid-state batteries (ASSBs) are promising next-generation batteries owing to their improved safety compared with lithium-ion batteries using flammable liquid electrolytes. Among various solid electrolytes, sulfide-based electrolytes exhibit high ionic conductivities, and their ductile properties allow them to be easily processed without high-temperature sintering. In sulfide-based ASSBs, a polymer binder is essential for achieving a good cycling performance by maintaining strong interfacial contacts in the composite electrodes during cycling. In this study, we prepared a composite Si-C anode and a LiNi0.82Co0.1Mn0.08O2 cathode using a nitrile-butadiene rubber binder for ASSB applications, and investigated the effect of the binder content on the mechanical properties and electrochemical performance. The binder content significantly influenced the physical and electrochemical characteristics of the composite electrodes, and the ASSB prepared with 1.5 wt% binder showed the best cycling performance considering capacity retention and rate capability. Furthermore, we investigated how the excess binder adversely affected the cycling performance through time-of-flight secondary ion mass spectrometry analysis.

Engineering a superamphiphilic surface for enhanced interfacial bonding in metal-polymer hybrid structure

Insufficient wetting of polymer due to its poor compatibility with metals leads to non-intimate interfacial mutual contact during the thermal-direct bonding process, thus hindering the establishment of effective mechanical interlocking and substantial chemical bonding at the interface, resulting in deficient performance of metal-polymer hybrid structures. To achieve high-quality bonding between non-polar ultra-high molecular weight polyethylene (UHMWPE) and Ti6Al4V titanium alloy (TC4) for the application of artificial joint prostheses, this study innovatively engineered a superamphiphilic (simultaneously superhydrophilic and superlipophilic) TC4 surface, which was achieved through a morphology-chemistry dual regulation strategy. This pretreatment strategy aimed at improving the interfacial compatibility between in-situ oxidized UHMWPE and TC4 and ensuring intimate contact between these two materials during thermal-direct bonding, thus facilitating chemical reactions and mechanical interlocking at the interface. Defect-free and ultra-high-performance TC4-UHMWPE hybrid joints were successfully obtained via friction spot joining (FSpJ) with the lap shear strength reaching 18.05 MPa (higher than all those similar hybrid joints reported in existing literature) and the fracture was confined to the UHMWPE matrix, effectively avoiding interfacial failure. The formation of chemical bonds in the form of COTi at TC4/UHMWPE interface was solidly confirmed based on X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses. This research presents a compelling strategy for improving interfacial compatibility between polymer and metal for thermal-direct bonding, to overcome the general difficulties in achieving effective interfacial bonding between these two categories of materials with significantly different physiochemical properties.

Efficient Flotation Separation of Ilmenite and Olivine in a Weak Alkaline Pulp Using a Ternary Combination Collector Centered around Al3.

Due to the similar physical and chemical properties of ilmenite and olivine, separating them is challenging. The flotation process, with the use of collectors, is an effective method. In this study, a ternary collector consisting of aluminum ion (III), benzohydroxamic acid (BHA), and sodium oleate (NaOL) was prepared for the flotation separation of ilmenite and olivine. Through micro-flotation experiments, molecular dynamics simulation (MD), density functional theory (DFT), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis, the synergistic effect between the components of the ternary collector and the adsorption configuration on the surface of ilmenite was investigated. The results revealed that at pH = 8, Al (III), BHA, and NaOL could coordinate and adsorb effectively on the surface of ilmenite, enhancing its floatability for separation from olivine. The adsorption configuration differed from previous reports, showing a co-adsorption of multiple forms on the surface of ilmenite.

Reactive Gas Cluster Ion Beams for Enhanced Drug Analysis by Secondary Ion Mass Spectrometry.

In this study, we investigate the formation and composition of Gas Cluster Ion Beams (GCIBs) and their application in Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis. We focus on altering the carrier gas composition, leading to the formation of (Ar/CO2)n or (H2O)n GCIBs. Our results demonstrate that the addition of a reactive species (CO2) to water GCIBs significantly enhances the secondary ion yield of small pharmaceutical compounds in the positive ion mode. In negative ion mode, the addition of CO2 resulted in either a positive enhancement or no effect, depending on the sample. However, an excess of CO2 in the carrier gas leads to the formation of carbon dioxide clusters, resulting in reduced yields compared to that of water cluster beams. Cluster size also plays a crucial role in overall yields. In a simple two-drug system, CO2-doped water clusters prove effective in mitigating matrix effects in positive ion mode compared to pure water cluster, while in negative ion mode, this effect is limited. These clusters are also applied to the analysis of drugs in a biological matrix, leading to more quantitative measurements as shown by a better fitting calibration curve. Overall, the doping of water clusters with small amounts of a reactive gas demonstrates promising benefits for higher sensitivity, higher resolution molecular analysis, and imaging using ToF-SIMS. The effectiveness of these reactive cluster beams varies depending on the experimental parameters and sample type.

Oceanic and Sedimentary Microbial Sulfur Cycling Controlled by Local Organic Matter Flux During the Ediacaran Shuram Excursion in the Three Gorges Area, South China.

The increased difference in the sulfur isotopic compositions of sedimentary sulfate (carbonate-associated sulfate: CAS) and sulfide (chromium-reducible sulfur: CRS) during the Ediacaran Shuram excursion is attributed to increased oceanic sulfate concentration in association with the oxidation of the global ocean and atmosphere. However, recent studies on the isotopic composition of pyrites have revealed that CRS in sediments has diverse origins of pyrites. These pyrites are formed either in the water column/shallow sediments, where the system is open with respect to sulfate, or in deep sediments, where the system is closed with respect to sulfate. The δ34S value of sulfate in the open system is equal to that of seawater; on the contrary, the δ34S value of sulfate in the closed system is higher than that of seawater. Therefore, obtaining the isotopic composition of pyrites formed in an open system, which most likely retain microbial sulfur isotope fractionation, is essential to reconstruct the paleo-oceanic sulfur cycle. In this study, we carried out multiple sulfur isotope analyses of CRS and mechanically separated pyrite grains (>100 μm) using a fluorination method, in addition to secondary ion mass spectrometry (SIMS) analyses of insitu δ34S values of pyrite grains in drill core samples of Member 3 of the Ediacaran Doushantuo Formation in the Three Gorges area, South China. The isotope fractionation of microbial sulfate reduction (MSR) in the limestone layers of the upper part of Member 3 was calculated to be 34ε = 55.7‰ and 33λ = 0.5129 from the δ34S and Δ33S' values of medium-sized pyrite grains ranging from 100 to 300 μm and the average δ34S and Δ33S' values of CAS. Model calculations revealed that the influence of sulfur disproportionation on the δ34S values of these medium-sized pyrite grains was insignificant. In contrast, within the dolostone layers of the middle part of Member 3, isotope fractionation was determined to be 34ε = 47.5‰. The 34ε value in the middle part of Member 3 was calculated from the average δ34S values of the rim of medium-sized pyrite grains and the average δ34S values of CAS. This observation revealed an increase in microbial sulfur isotope fractionation during the Shuram excursion at the drill core site. Furthermore, our investigation revealed correlations between δ34SCRS values and CRS concentrations and between CRS and TOC concentrations, implying that organic matter load to sediments controlled the δ34SCRS values rather than oceanic sulfate concentrations. However, these CRS and TOC concentrations are local parameters that can change only at the kilometer scale with local redox conditions and the intensity of primary production. Therefore, the decreasing δ34SCRS values likely resulted from local redox conditions and not from a global increase in the oceanic sulfate concentration.

Synthesis and Characterization of Metallic (Fe‐Ni, Fe‐Ni‐Si) Reference Materials for SIMS 34S/32S Measurements

Secondary ion mass spectrometry (SIMS) is often used to determine the sulfur contents and isotope ratios of metallic alloys in meteorites or high‐pressure experimental samples. However, SIMS analyses involve calibration and the determination of instrumental mass fractionation in reference materials with a matrix composition similar to that of the unknown samples. To provide metallic reference materials adapted to S measurements via SIMS, we synthesised a series of twenty‐eight alloys comprising four FeNi(±Si) compositions (Fe95Ni5, Fe90Ni10, Fe80Ni20, and Fe80Ni15Si5) with S contents varying from 100 μg g−1 to 4 g/100g using the “melt spinning” method, which guarantees that the metal alloys are rapidly quenched at ~ 106 K s−1. Sulfur contents were determined at the Service d'Analyse des Roches et Minéraux at the CRPG and absolute δ34S values were determined by multi‐collector ICP‐MS (MC‐ICP‐MS, ThermoScientific Neptune) and isotope ratio mass spectrometry (Thermoscientific Delta V). A δ34S value of 16.01 ± 0.31‰ was consistently obtained using the MC‐ICP‐MS, which was indistinguishable of the δ34S value of the FeS starting material (15.95 ± 0.08‰). It suggests that S did not undergo isotopic fractionation during the melting process. Of fifteen samples containing ≤ 5000 μg g−1 S, SIMS measurements with 15‐μm‐diameter spots were repeatable to within 10% relative (1 standard deviation, 1s) for S contents and 2‰ for δ34S values. However, samples containing > 5000 μg g−1 S showed FeNi–FeS immiscibility, leading to minor dispersion of the S mass fractions and δ34S values. No matrix effect was observed for Fe‐Ni, Si, or S contents in terms of the calibration curves and instrumental mass fractionation. We ultimately recommend eight samples as reliable reference materials for S isotopic measurements by SIMS, which we can share worldwide with other laboratories.

Characterization of Growth Sectors in Gallium Nitride Substrate Wafers

During crystal growth processes, growth sectors are formed due to growth along different crystallographic directions. Although the crystal structure in the different growth sectors is unchanged, strain induced topography contrast is observed by synchrotron X-ray topography. In this study, synchrotron monochromatic beam X-ray topography (SMBXT), synchrotron X-ray plane wave topography (SXPWT), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and secondary ion mass spectrometry (SIMS) are used to characterize growth sectors in gallium nitride (GaN) substrate wafers grown by patterned hydride vapor phase epitaxy (HVPE). The SMBXT images reveal the boundaries of {0001} and {1122} type growth sectors. Strain maps generated from SXPWT shows that the out-of-plane strains in different growth sectors have a difference of the order of 10-5. SEM images from SE2 signal shows no contrast of growth sector boundaries while images from Robinson detector (RBSD) show different growth sectors as different grey scale contrast, indicating a strain effect. SIMS analysis shows that the different oxygen impurity levels in the growth sectors, which is the origin of the strain. A formation mechanism of growth sectors in patterned HVPE grown GaN wafers is proposed.

An alternative chlorine-assisted optimization of CdS/Sb2Se3 solar cells: Towards understanding of chlorine incorporation mechanism

The current strategies in the development of Sb2Se3 thin film solar cells involve fabrication and optimization of superstrate and substrate device architectures, with the preferable choice for TiO2 and CdS heterojunction layers. For CdS-based superstrate cells, several studies reported the necessity to apply CdCl2 or other metal halide-based post-deposition treatment (PDT), highlighting improvement of CdS/Sb2Se3 device efficiency. However, the need, effect, and mechanism of such PDT are very often not described. Additionally, the fact that many groups have not succeeded in demonstrating its benefits suggests that this strategy is not straightforward, requiring a deeper understanding towards a more unified concept. The present study proposes an alternative approach to the challenging CdCl2 PDT of CdS in CdS/Sb2Se3 device, involving controllable Cl incorporation in CdS films by systematically varying the concentration of NH4Cl in the CBD precursor solution from 1 to 8 mM. Structural and electrical characterizations are correlated with advanced measurements of Scanning Kelvin Probe, surface photovoltage, and atomic force microscopy to understand the impact of Cl incorporation on the properties of CdS films and CdS/Sb2Se3 devices. The validity of Cl incorporation in the CdS lattice and interdiffusion processes at the CdS-Sb2Se3 interface is confirmed by secondary ion mass spectrometry analysis. It is demonstrated that incorporation of 1 mM of NH4Cl, as a Cl source in CBD CdS, can boost the PCE of CdS/Sb2Se3 by ∼20 %. With this approach, we offer new perspectives on the optimization methodology for Cl-based CdS/Sb2Se3 device processing and complementary understanding of the physiochemistry behind these processes.

Update on the 53Mn-53Cr ages of dolomite in the Ivuna CI chondrite and asteroid Ryugu sample

Aqueous alteration in planetesimals is one of the earliest geological processes in the solar system. The timing of aqueous alteration sheds light on the timescale of material evolution through water–rock interaction in small bodies. The 53Mn-53Cr decay system, where a short-lived radionuclide 53Mn decays to 53Cr with a half-life of 3.7 Myr, is a powerful tool for dating carbonates in primitive meteorites that formed during aqueous alteration. In CI chondrites and samples returned from asteroid Ryugu, a major carbonate mineral is dolomite (CaMg(CO3)2) and could be dated precisely because of their relatively high Mn abundances. However, the lack of a proper dolomite standard for secondary ion mass spectrometry (SIMS) hinders us from obtaining accurate Mn/Cr ratios of carbonates, resulting in erroneous formation ages. In this work, we synthesized Mn-, Cr-, and Fe-bearing crystalline dolomite as standard materials and evaluated the relative sensitivity factor (RSF) of Mn/Cr for SIMS analysis, namely, the ratio of Mn/Cr obtained using SIMS to true Mn/Cr. We found that the RSF values of the dolomite standards range from 0.8 to 0.9, slightly higher than that of calcite (CaCO3) (∼0.7), and increase with their Fe contents. We used the newly evaluated RSF values to date dolomite in the Ivuna CI chondrite and obtained an initial 53Mn/55Mn ratio of (3.95 ± 0.49) × 10−6 (95 % confidence interval) and the corresponding absolute age of 4564.0 + 0.6/−0.7 Ma. Our new initial 53Mn/55Mn ratio is 26 ± 19 % higher than that obtained by a previous study for the same dolomite grain using a calcite standard. This difference is consistent with the difference between the RSF values of dolomite and calcite. Based on these results, we updated the initial 53Mn/55Mn ratio previously reported for dolomite in the Ryugu sample A0058 to be (3.21 ± 0.66) × 10−6, which corresponds to an absolute age of 4562.8 + 1.0/−1.2 Ma. This age seems to be the best estimate for the formation age of dolomite in Ryugu currently available.

In-Situ Polymerized High-Voltage Solid-State Lithium Metal Batteries with Dual-Reinforced Stable Interfaces.

Solid polymer electrolytes (SPEs) represent a pivotal advance toward high-energy solid-state lithium metal batteries. However, inadequate interfacial contact remains a significant bottleneck, impeding scalability and application. Inadequate interfacial contact remains a significant bottleneck, impeding scalability and application. Recent efforts have focused on transforming liquid/solid interfaces into solid/solid ones through in situ polymerization, which shows potential especially in reducing interface impedance. Here, we designed high-voltage SSLMBs with dual-reinforced stable interfaces by combining interface modification with an in situ polymerization technology inspired by targeted effects in medicine. Theoretical calculations and time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis demonstrate that tetramethylene sulfone (TMS) and bis(2,2,2-trifluoromethyl) carbonate (TFEC) exhibit selective adsorption at the interface of the LiNi0.8Co0.1Mn0.1O2 (NCM) cathode and Li anode, respectively. These compounds further decompose to form a stable cathode-electrolyte interface (CEI) film and a solid electrolyte interface (SEI) film, thereby simultaneously achieving a superior interface between the SPE and both the Li anode and NCM cathode. The developed Li||SPE||Li cell sustained cycling for more than 1000 h at 0.3 mA cm-2, and the NCM||SPE||Li cell also demonstrated an excellent capacity retention of 86.8% after 1000 cycles at 1 °C. This work will provide valuable insights for the rational design of high-voltage SSLMBs with stable interfaces, leveraging in situ polymerization as a cornerstone technology.

First demonstration of Sn diffusion into gallium oxide from poly-tetraallyl tin deposited by initiated chemical vapor deposition by thermal treatment

Gallium oxide (Ga2O3) is attracting attention as a next-generation semiconductor material for power device because it has a wide energy band gap and high breakdown electric field. We deposited a Sn polymer, poly-tetraallyl tin, on Ga2O3samples using a disclosed initiated chemical vapor deposition (iCVD) process. The Sn dopant of the Sn polymer layer is injected into the Ga2O3through a heat treatment process. Diffusion model of Sn into the Ga2O3is proposed through secondary ion mass spectroscopy analysis and bond dissociation energy. The fabricated device exhibited typical n-type field-effect transistor (FET) behavior. Ga2O3Sn-doping technology using iCVD will be applied to 3D structures and trench structures in the future, opening up many possibilities in the Ga2O3-based power semiconductor device manufacturing process.

Separation of copper-lead using 2,5-dimercapto-1,3,4-thiadiazole as chalcopyrite depressant: Adsorption and hydrophilicity studies

Galena separation from chalcopyrite poses a notable challenge in mineral processing, owing to the involvement of high dosages of traditional process reagents and substantial environmental impact. This study addresses this challenge by introducing 2,5-dimethoxy-1,3,4-thiadiazole (DMTD) as a chalcopyrite depressant using sodium ethyl xanthate (NaEX) as a collector. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analyses showed that DMTD can be adsorbed on the surfaces of chalcopyrite and galena, but the adsorption on chalcopyrite is stronger than that on galena. UV–vis, zeta potential and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses revealed that DMTD impeded the adsorption of NaEX on chalcopyrite; moreover, NaEX could desorb the DMTD adsorbed on galena and re-adsorb it on galena. Surface hydrophilicity tests revealed that DMTD significantly enhanced the hydrophilicity of chalcopyrite in the presence of NaEX, and galena was selectively separated from chalcopyrite using 1×10− 4 mol/L DMTD at pH exceeding 5. The recovery of galena remained >90 %, while that of chalcopyrite drastically decreased to <5 %. Furthermore, artificial-mixing experiments confirmed the separation effect of DMTD as a chalcopyrite depressant. Notably, this study avoids environmental pollution caused by traditional depressants, offering a potential green approach to achieve effective flotation separation of copper–lead sulfide ore.