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Two-dimensional (2D) transition metal dichalcogenides with 2H-phases, as a unique platform of valleytronics, display valley polarization and the well-known anomalous valley Hall effect when stacking with 2D magnetic substrates. In this study, we employ first-principles calculations to investigate the magnetic states, band structures, and magnetic proximity-dependent valley properties of 2D van der Waals heterostructures Cr2Ge2Te6/2H-MX2 (M = Mo, W, and X = S, Se, Te). Our findings reveal that the heterostructures possess stacking-dependent spontaneous valley polarization as well as pristine perpendicular magnetic anisotropy. Additionally, the Berry curvature and circular polarization demonstrate the presence of spin–momentum coupling characteristics, while the calculated non-zero Hall voltage indicates that the anomalous valley Hall effect can be achieved in valley-polarized systems. Furthermore, due to the strain effect and the electronic polarization at the interface, Cr2Ge2Te6/2H-MX2 heterostructures undergo the transition from semiconductors to semimetals upon substitution of early chalcogen elements. These calculations provide valuable insights for practical applications of valleytronics in 2D van der Waals heterostructure systems. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive exploration of low interface trap density (Dit) in HfO2/Si0.73Ge0.27 metal-oxide semiconductor (MOS) capacitors achieved through sulfur passivation and post-deposition annealing (PDA). Our investigation revealed that devices subjected to sulfur passivation and PDA exhibit noteworthy reductions in Dit and hysteresis. Specifically, a low Dit value of 1.2 × 1011 eV−1 cm−2 has been achieved at Ei–0.1 eV for the SiGe MOS device. The observed enhancement in interface properties can be attributed to two key factors: the reduction of the GeOx concentration in the interfacial layer (IL) by sulfur passivation on the SiGe surface and the IL densification with stoichiometric oxygen during PDA. [ABSTRACT FROM AUTHOR]

Alloying and site ordering play complementary roles in dictating a material's properties. However, deconvolving the impacts of these separate phenomena can be challenging. In this work, we simulate structures of Zn (Sn , Ge) N 2 with varied Sn content and site ordering to determine the impacts of order and composition on structural and electronic properties. We assess the formation enthalpy, lattice parameters, elastic constants, spontaneous polarization, and piezoelectric coefficients. In mostly disordered structures (order parameters ranging from 0.2 to 0.4), the formation enthalpy exhibits local extrema as a function of the order parameter, deviating from the more linear trends seen in both fully disordered and fully ordered systems. This anomalous deviation from the otherwise linear trend in formation enthalpy with order manifests in each of the other properties calculated. This range of order parameters of interest may be caused by a transition in the ordering of the quaternary material similar to phase changes seen in ternary compounds but stretched over a region inclduing 20% of the order parameter range. Most parameters calculated are more sensitive to order than to composition in the limited composition range tested; however, the lattice parameter c , piezoelectric coefficient e 33 , and elastic moduli C 12 , C 13 , and C 23 are more sensitive to composition. Of the properties compared, the piezoelectric coefficients are influenced most significantly by changes in both the composition and order parameter. Lattice parameters undergo the smallest changes with order and composition, but these small differences appear to impart large trends in the other properties. Better understanding the effects of disorder and group IV alloying in Zn (Sn , Ge) N 2 allows for more accurate modeling of characteristics of this material system for solid state lighting and other applications. [ABSTRACT FROM AUTHOR]

The effect of inserting a nm-scale layer of Zn(Si,Ge)N2 into an AlGaN quantum well structure designed for light emission in the wavelength range from 255 to 305 nm is investigated here. The enhanced confinement of the hole within the quantum well results in an enhancement of the overlap of the hole and electron wave functions, resulting in an enhancement of the radiative recombination rate. In this theoretical calculation, for emission at a 270 nm wavelength, the enhancement in the wavefunction overlap can reach a factor of 7 when compared to an AlGaN quantum well device specifically engineered for optimal emission at the identical wavelength. Increases of almost an order of magnitude in both the peak spontaneous emission intensity and the radiative recombination rate are predicted. The peak emission wavelength can be tuned from 255 to 305 nm by adjusting the width and/or the composition of the inserted layer. The proposed structures provide a route to higher efficiency ultraviolet practical light emitting diodes and lasers. [ABSTRACT FROM AUTHOR]

Silicon nitride (Si 3 N 4) material holds significant potential as a widespread applied biomedical material with high reliability in mechanical properties and biological activity. This study utilized 3D printing techniques to fabricate Si 3 N 4 bioceramics reinforced with zinc oxide (ZnO) nanowires, which overcomes the dilemma faced by traditional Si 3 N 4 materials, which possess excellent mechanical properties but lack sufficient antibacterial performance, or porous Si 3 N 4 materials that exhibit good antibacterial properties yet suffer from poor mechanical characteristics. Compared to Ti-alloy, Al 2 O 3 , PEEK, and conventional Si 3 N 4 materials, the Si 3 N 4 bioceramic with an addition of 5 wt percent (wt%) ZnO nanowires retains superior mechanical properties: bending strength of 735 MPa, fracture toughness of 8.25 MPa m1/2, vickers hardness of 14.8 GPa, and compressive strength of 2575 MPa. Furthermore, the material demonstrates commendable biocompatibility and outstanding antibacterial effects. Cellular activity on the surface of this material is also noted to be exceptionally vigorous. Research indicates that the synergistic effects of 3D printing characteristics and the appropriate inclusion of ZnO nanowires, which positively interact with β-Si 3 N 4 crystals, are primarily responsible for the exceptional comprehensive performance of 3D printed Si 3 N 4 bioceramics. [ABSTRACT FROM AUTHOR]

Aluminum and magnesium are the lightest structural metals, and therefore, various alloys based on them are widely used in both, automotive and aerospace industries. However, aluminum and magnesium are very easily affected by atmospheric and aqueous corrosion, and, therefore, the alloying elements should enhance their corrosion stability. In this work, the thermodynamic analysis of phase and chemical equilibria involving aluminum and magnesium alloys doped with silicon in oxygen–containing air environments, as well as the analysis of chemical and electrochemical equilibria involving these alloys in aqueous environments is conducted. The phase and chemical equiliibria in the Al–Mg, Al–Si, Mg–Si, and Al–Mg–Si systems at 298 K are considered, and the thermodynamic activities of the components of common Al–Mg–Si system alloys are calculated. The invariant chemical equilibria in the systems Al–Mg–O, Al–Si–O, Mg–Si–O at 298 K are considered, the isothermal section of the state diagrams of these systems are plotted, and the oxidation scheme of the Al–Mg–Si system alloys in excess oxygen is proposed. The chemical and electrochemical equilibria in the Al–Mg–Si–H2O system at 298 K are considered and presented in form of the activity – pH and the potential – pH diagrams, and the oxidation of the Al–Mg–Si system alloys in aqueous environments is discussed. [ABSTRACT FROM AUTHOR]

The field-effect transistors (FETs) based on reduced graphene oxide (rGO) with SiO2, porous silicon (PS), and oxidized porous silicon (PSox) supporting layers were obtained. The influence of charged impurities in the silicon substrate and electrically active defects in the support layers on the electrical properties of the FETs was studied based on the capacitance-voltage characteristic analysis. Localized electron states in the SiO2, PS, and PSox supporting layers that affect the charge transfer in the rGO-based FETs were determined using thermally stimulated depolarization spectroscopy. The influence mechanisms of various supporting layers on the electrical characteristics of the obtained FETs are discussed. [ABSTRACT FROM AUTHOR]

The impact of silicon and aluminum on phase transformation behavior, particularly bainite, and microstructure evolution in Fe–0.2C–2.5Mn steel are presented. Continuous–cooling–transformation (CCT) and time–temperature–transformation (TTT) diagrams are determined experimentally. An aluminum extended empirical formula is introduced to estimate the martensite start temperature (Ms) with a thorough assessment of existing formulae. Results show that aluminum significantly increases Ms and has a stronger influence on promoting ferritic microstructures than silicon. During continuous cooling, alongside bainite, formation of Widmanstätten structures is induced in aluminum‐alloyed steel at higher cooling rates due to increased prior austenite grain size. Silicon decelerates bainite transformation kinetics by enhancing austenite's chemical stability through carbon enrichment via preventing carbide precipitation and by strengthening austenite against displacive phase transformation via solid solution hardening. Although aluminum has similar effects, incubation time is shortened during isothermal treatment because of the increased driving force, which overcompensates for the retardation effects. A finer carbide‐free bainitic microstructure is achieved in aluminum‐alloyed steel with more pronounced film‐like retained austenite (RA) formation and superior carbon enrichment, improving RA stability and suppressing martensite–austenite island formation. Finally, with the proposed formula, an accurate approximation to experimental Ms is accomplished. [ABSTRACT FROM AUTHOR]

We report an obvious improvement in the performance of a separated absorption charger-layer multiplication Ge/Si avalanche photodetector, achieved by passivating the sidewalls with a low-temperature remote oxygen plasma (ROP) treatment. The dangling bonds on the Ge surface can be efficiently passivated by the formation of an ideal Ge/GeO2 interface. With ROP passivation, the leakage current of the device shows a three- to fourfold decrease at 300 K, resulting in a dark current (I dark) of 3.5 × 10−6 A at 90% avalanche voltage (V br) and 3.4 × 10−7 A at punch-through voltage (V puhch-through) for the 26 μ m-diameter device. A reduction of over tenfold is demonstrated at 200 K and the passivation mechanism is revealed. In addition, a multiplication gain of 94 is obtained under 1550 nm illumination. The device with ROP passivation shows an improved gain bandwidth product of 190 GHz. The enhanced high-frequency response of the device with ROP passivation can be attributed to the alleviation of the retarding effect caused by the interface state on the sidewalls. Without using a trans-impedance amplifier, an opening eye diagram at 28 Gbps is demonstrated, indicating reliable device transmission performance. [ABSTRACT FROM AUTHOR]

[Display omitted] Silicon is considered as the next-generation anode material for lithium-ion batteries due to its high theoretical specific capacity and abundant crustal abundance. However, its poor electrical conductivity results in slow diffusion of lithium ions during battery operation. Simultaneously, the alloying process of silicon undergoes a 300 % volume change, leading to structural fractures in silicon during the cycling process. As a result, it loses contact with the current collector, continuously exposing active sites, and forming a sustained solid electrolyte interface (SEI) membrane. This paper presents the design of a fluorine-ion-regulated yolk–shell carbon-silicon anode material, highlighting the following advantages: (a) Alleviating volume changes through the design of a yolk–shell structure, thereby maintaining material structural integrity during cycling. (b) Carbon shell prevents silicon from coming into contact with the electrolyte, simultaneously improving silicon's electrical conductivity and increasing ion/electron conductivity. (c) Utilizing fluorine-ion interface modification to obtain an SEI membrane rich in fluorine components (such as LiF), thereby enhancing its long cycling performance. The F-Si@Void@C exhibits outstanding electrochemical performance, with a reversible capacity of 1166 mAh/g after 900 cycles at a current density of 0.5 A/g. [ABSTRACT FROM AUTHOR]

This research paper explores the structural, electronic, magnetic, elastic, dynamic, and thermoelectric properties of sp-based half-Heusler (HH) RbBaX (X = Si and Ge) compounds using density functional theory (DFT) and the full-potential linearized augmented plane wave (FP-LAPW) method within the WIEN2k software package. We evaluate the exchange correlation potential using two different approaches: The generalized gradient approximation (GGA) and the modified Becke–Johnson approach. We observe that RbBaX (X = Si and Ge) adopts a ferromagnetic configuration based on the analysis of total energy against volume. We establish that these alloys possess a genuine half-metallic character because of the full spin polarization observed at the Fermi level in their electronic spectrum. Both compounds under investigation have a total magnetic moment of 1.00 μ B, in agreement with the Slater–Pauling principle. The Born stability criteria for cubic structures and phonon dispersion patterns confirm the mechanical and dynamic stability of RbBaX (X = Si and Ge) alloys. The thermoelectric properties reveal a p-type semiconductor nature, characterized by significant positive Seebeck values. The thermoelectric figure of merit (ZT) calculated for both alloys at 300 K approaches unity, highlighting their remarkable thermoelectric efficiency. [ABSTRACT FROM AUTHOR]

Zeolites HY with different hydrophobicity having Si/Al ratios of 10, 100 and 750 were modified by an ion exchange process with nitrate solutions of alkali cations in the concentration range 0.1 - 100 mM. The modified samples were characterized by ICP-OES, XRD and surface analysis with N2-adsorption. The ethylene adsorptivities of these modified zeolites were measured under degassed and non-degassed conditions. All zeolites showed the enhancement in ethylene adsorptivity upon modification, while the K+ ions modified ones showed the best enhancement. The modified hydrophobic zeolites with Si/Al ratios of 100 and 750 showed no differences in adsorptivity under the degassed and non-degassed conditions. However, for less hydrophobic zeolite (Si/Al = 10), the adsorption under the degassed condition was much higher than the adsorption under the non-degassed condition. These results indicate that the modified hydrophobic zeolites with Si/Al ratios of 100 and 750 are suitable as ethylene scavengers at ambient conditions. [ABSTRACT FROM AUTHOR]

The intermittent nature of renewable energy generation can be tackled by integrating them with electrochemical energy storage, which can also close the gap between supply and demand effectively. It has recently been demonstrated that Si3N4‐based negative electrodes are a promising option for lithium‐ion batteries due to their large theoretical capacity and appropriate working potential with extremely low polarization. In the present work, Si3N4 was utilized as anode material in all‐solid‐state lithium‐ion battery with lithium borohydride as a solid electrolyte and Li foil placed as a counter electrode. The electrochemical properties were investigated using galvanostatic charge/discharge profiling whereas the mechanism of lithiation delithiation was investigated in detail using x‐ray diffraction (XRD). The highest capacity of the composite materials was obtained as 1700 mAhg−1 at 0.05 C current rate in the first cycle, which is reduced to 370 in 5 cycles. However, a stability in the capacity was observed in subsequent cycles and a retention of almost 88% could be achieved in 150 cycles. The interfacial resistance before and after the electrochemical cycling was observed as 326 Ω and 13 kΩ, respectively which is also supported by the microstructural investigations where the cracks are observed because of thermochemical reactions. [ABSTRACT FROM AUTHOR]

The effect of electrokinetic sodium silicate injection into sand formation containing fine grains was studied in this research. A soil was grouted by Na-silicate in a 160 mm length electrokinetic cell with a 1 V/cm potential gradient for 1 week. Silicate solutions of 5% and 10% concentrations were injected through the reservoir next to the anode electrode, while 10% phosphoric acid or 30 mg/l bicarbonate solutions were used in the cathode chamber. When comparing the results, it was evident that the electrokinetic (EK) process without additives does not significantly enhance soil strength, except in the vicinity of the cathode electrode. Specifically, the most notable increase in strength was observed in the section proximal to the cathode, which demonstrated approximately 3.1 times higher strength than the control sample (i.e., without EK application). The obtained results indicate that injecting 5% and 10% Na-silicate solutions significantly increase the strength of soil all over the sample. Significant improvement in soil strength was observed when Na-Si was injected with bicarbonate as a catholyte during the EK process. Strength at the anode increased by 82% and 107% at 5% and 10% Na-Si concentrations, respectively. Resistance in the middle of the cell samples remained consistent for both concentrations. Immediate application of bicarbonate catholyte and silicate injection notably enhanced soil strength, while efficiency decreased when Na-Si was injected with phosphoric acid catholyte, especially near the cathode. Higher silicate concentrations resulted in reduced penetration length in both acid and bicarbonate catholytes. It can also be concluded that adding silicate to the anode chamber meaningfully reduces the electro-osmotic flow after 2 or 3 days. [ABSTRACT FROM AUTHOR]

Density functional theory was employed to investigate the structural, electronic, elastic, thermodynamic, and thermoelectric characteristics of RhNbZ (Z = Si, Ge) half-Heusler materials. Furthermore, RhNbZ (Z = Si, Ge) alloys adhere to the semiconductor behaviour dictated by the Slater–Pauling rule. Elastic property calculations affirm the mechanical stability of the compounds. Next, we use density functional perturbation theory (DEPT) to predict the dynamical context of these ordered systems. Utilizing the Debye quasi-harmonic model, we explored the thermodynamic properties of these half-Heusler alloys. The thermoelectric properties of the materials were evaluated using the semi-classical Boltzmann theory, which was implemented in the BoltzTraP code. A remarkably high figure of merit values for RhNbZ (Z = Si, Ge) compounds suggests their potential for thermoelectric applications across a wide temperature range. Optical properties, including dielectric function, absorption coefficient, refractive index, reflectivity, and optical conductivity, were calculated and discussed. Notably, the materials exhibit exceptional absorption coefficients α(ω) in the ultraviolet and visible regions of the light spectrum, indicating their suitability for applications in photovoltaic and optical equipment manufacturing. [ABSTRACT FROM AUTHOR]

In silicon-based hybrid anodes, the uniform hybridization of silicon with conducting/buffering matrices is very critical in achieving desirable lithium storage performance. Herein, a cyanosol-derived electrostatic assembly and pyrolysis route has been developed to construct homogeneous silicon/metal/carbon (Si/M/C) ternary materials. Specifically, Si nanoparticles surrounded by ultrafine FeCo alloy are uniformly anchored on graphene (G), yielding a Si/FeCo/G nanohybrid. The incorporation of M/C dual matrices, with ultrafine alloy nanocrystals evenly distributed on graphene, into silicon could be responsible for the improved structural stability and charge-transport capability of the ternary anode. As a result, the Si/FeCo/G nanohybrid manifests good cycling stability (1426 mA h g−1 after 100 cycles at 0.5 A g−1) and high rate performance (1266 and 1118 mA h g−1 at 5 and 10 A g−1, respectively). [ABSTRACT FROM AUTHOR]

Silicon emerges as a candidate for advancing lithium ion batteries with important roles in various applications ranging from portable electronics to electric vehicles. However, despite its theoretical capacities silicon faces challenges such as unstable cycling and limited rate performance. This thorough review examines developments in improving the electrochemical performance of silicon and graphene within the context of lithium ion batteries. The focus lies on strategies for designing and synthesizing composite materials that incorporate silicon particularly when combined with graphene. Structural aspects like particle size, morphology and porosity are carefully optimized to harness the potential of silicon based anodes and graphene. The review highlights the effects resulting from these tailored design approaches, including key factors such as capacity retention, cycling stability and rate capability of the resulting anode materials. By exploring these design paradigms this review offers a comprehensive perspective on the transformative capabilities of silicon, graphene and silicon/graphene composites. It does not highlights recent advancements but also outlines future directions for innovation and practical applications. This compilation of progress contributes to the understanding of how silicon based anodes, in lithium ion batteries have evolved from small‐scale implementations to catalyzing advancements in energy utilization. [ABSTRACT FROM AUTHOR]

This paper studies the process of SiC abrasive particles abrasive flow machining iron-carbon alloy surface through molecular dynamics simulation from the microscopic angle of different cutting angles SiC particles cutting force, workpiece atomic energy, workpiece atomic displacement, workpiece internal lattice structure and dislocation variation law, explore and clarify the SiC abrasive particles micro-cutting iron-carbon alloy mechanism. The results show that, in the micro-cutting process, when the cutting angle of the abrasive increases, the working surface of the iron-carbon alloy will produce deeper cutting marks, the cutting force of the SiC particles and the atomic energy of the workpiece have an significant upward trend, the atomic displacement is more complex, the lattice deformation is intensified, and the reconstruction and amorphous phase transformation occur, the number of dislocations increases, and the distribution is denser, and the surface machining quality of the workpiece decreases. Therefore, selecting a smaller cutting angle can reduce the probability of forming the workpiece's internal defect structure and improve the workpiece's surface machining quality. [ABSTRACT FROM AUTHOR]

High-temperature gas-cooled reactors (HTGRs) have garnered considerable interest due to their superior efficiency and inherent safety. This study systematically investigates the interaction between silver-palladium (Ag-Pd) alloy and silicon carbide (SiC) coating in tri-structural isotropic (TRISO) particles of HTGRs, focusing on the potential release of radioactive Ag-110 m through SiC cladding. Operating temperatures ranging from 800–1100 °C were examined to understand the mechanisms of Ag-Pd migration in SiC. Advanced techniques like transmission electron microscopy (TEM), focused ion beam (FIB) coupled with 3D visualization and scanning precession electron diffraction (SPED) integrated with machine learning were employed to identify two pathways of Pd-assisted Ag migration: (1) (Pd,Ag) 2 Si and (Pd,Ag) 3 Si acting as migration channels, and (2) Pd-rich phases increasing SiC disorder, enhancing Ag diffusion. Significantly, a carbon barrier formation above 1000 °C was observed, which inhibits Ag-Pd/SiC interaction. These findings offering new insights for predicting nuclear reactor lifespan and data support to optimize TRISO particles' structural design. [Display omitted] [ABSTRACT FROM AUTHOR]

Si x Ge 1 − x − y Sn y ternary alloys are a candidate material system for use in solar cells and other optoelectronic devices. We report on the direct transition energies and structural properties of Ge-rich Si x Ge 1 − x − y Sn y alloys with six different compositions (up to 10% Si and 3% Sn), lattice-matched to Ge or GaAs substrates. The direct interband transitions occurring at energies between 0.9 and 5.0 eV were investigated using spectroscopic ellipsometry, and the resulting data were used to obtain the dielectric functions of the Si x Ge 1 − x − y Sn y layer by fitting a multilayer model. Values for the E 0 , E 1 , Δ 1 , E 0 ′ , and E 2 transition energies were then found by identifying critical points in the dielectric functions. Structurally, the composition of the samples was measured using energy-dispersive x-ray measurements. The lattice constants predicted from these compositions are in good agreement with reciprocal space maps obtained through x-ray diffraction. The results confirm that a 1 eV absorption edge due to direct interband transitions can be achieved using relatively low Si and Sn fractions (< 10 % and < 3 %, respectively), although the bandgap remains indirect and at lower energies. The higher-energy critical points show smaller shifts relative to Ge and match results previously observed or predicted in the literature. [ABSTRACT FROM AUTHOR]

The paper summarizes the results of numerous works performed by the employees of the Pobuzky Ferronickel Plant, the Department of Electrometallurgy of the USU of Science and Technology (Dnipro), RPC "Technosplavy" under the leadership of Mykhailo Hasyk, academician of NASU. A technology of low iron recovery has been implemented at the plant, which allows producing high-percentage black ferronickel, containing 30-50 % Ni, and almost hundredth fractions of carbon and silicon, directly in electric furnaces. The thermodynamic features of out-of-furnace ladle desulfurization of ferronickel with soda are considered. A complex technology has been developed and implemented, which involves mixing black ferronickel with a reduced silicon and carbon content (up to 0.01 %) and a high nickel content (over 50 %) produced in one furnace with an alloy from another furnace with a low nickel concentration (10-17 %) and a high concentration of silicon and carbon, which are so necessary for desulfurization with soda in a ladle. The developed and proposed technological schemes for the enrichment of electric furnace slags using the "wet" technology and refining slags using the "dry" technology make it possible to recycle about 1,200 tons of nickel per year, or to extract 31.6 % and 94.65 % of nickel from the slags, respectively. [ABSTRACT FROM AUTHOR]

The gradient-distributed binders have better energy dissipation and stress relief capabilities under stress to maintain stability of Si electrode. [Display omitted] Silicon is considered as a promising alternative to traditional graphite anode for lithium-ion batteries. Due to the dramatic volume expansion of silicon anode generated from the insertion of Li+ ions, the binder which can suppress the severe volume change and repeated massive stress impact during cycling is required greatly. Herein, we design a gradient-distributed two-component binder (GE-PAA) to achieve excellent cyclic stability, and reveal the mechanism of high energy dissipative binder stabilized silicon electrodes. The inner layer of the electrode is the polyacrylic acid polymer (PAA) with high Young's modulus, which is used as the skeleton binder to stabilize the silicon particle interface and the electrode structure. The outer layer is the gel electrolyte polymer (GE) with lower Young's modulus, which releases the stress generated during the lithiation and de-lithiation process effectively, achieving the high structural stability at the molecular level and silicon particles. Due to the synergistic effect of the gradient binder design, the silicon electrode retains a reversible capacity of 1557.4 mAh g-1 after 200 cycles at the current density of 0.5 C and 1539.2 mAh g-1 at a high rate of 1.8 C. This work provides a novel binder design strategy for Si anode with long cycle stability. [ABSTRACT FROM AUTHOR]

Aluminium–silicon alloys are highly regarded for their lightweight and unique mechanical properties, making them crucial for various industrial applications. Achieving optimal mechanical behavior in Al-Si-based alloys necessitates meticulous control over their microstructure. The research investigated the impacts of heat treatment regimes on the microstructure of A356 hypoeutectic alloys by light optical microscope (OM), scanning electron microscope (SEM), and energy dispersive spectroscope (EDS). The alloy, produced via stir-casting, underwent homogenization at 540 °C/5 h, one-step (200 °C for 0.5–8 h (T1)) and two-step (T2 (200 °C/0.5 h/180 °C/0.5–8 h)), and T2L (200 °C/0.5 h/160 °C/0.5–8 h)) aging processes. The findings revealed significant microstructural changes due to heat treatment. Homogenization reduced the average grain size of eutectic silicon by 20.5%. The T1 treatment increased the grain size and changed the grain morphology with prolonged aging, negatively impacting the mechanical properties. The T2 and T2L treatments resulted in finer, more uniform grain structures. The T2L treatment produced the finest eutectic silicon and the most uniform grain distribution, indicating the superior potential for mechanical performance. Overall, this study underscores the importance of tailored heat treatment regimes to optimize the microstructure and enhance the structural sensitive properties of Al-Si alloys, benefiting automotive and aerospace industries. Article Highlights: Significant Microstructural Refinement: Homogenization at 540 °C/5 h reduced the eutectic silicon grain size by 20.5%, from 4.4 µm to 3.5 µm, demonstrating adequate refinement of the alloy's microstructure. Impact of Aging Treatments: One-step aging at 200 °C increased grain size and changed grain morphology from rounded to dendritic, while two-step aging treatments showed varying degrees of grain refinement, with finer structures observed at lower secondary aging temperatures (160 °C). Optimization for Industrial Applications: The study emphasizes the importance of optimizing aging times to balance grain refinement, highlighting the potential for tailored alloy microstructure development to enhance performance in aerospace and automotive sectors. [ABSTRACT FROM AUTHOR]

High-quality monolithic Ge-on-Si is sought for CMOS-compatible optoelectronic devices. We examine the structural characteristics of Ge-on-Si grown by the aspect ratio trapping (ART) method on a SiO2/Si(001) template in pre-patterned holes. Transmission electron microscopy and surface topography analysis revealed high-quality Ge islands overgrown from the ART holes in SiO2. The superior crystal quality of Ge ART growth was also confirmed by comparing x-ray diffraction (XRD) data of Ge ART and Ge planar epilayer samples. The XRD and micro-Raman data additionally show a small residual strain in the islands which vanishes by reducing the hole diameter from 280 nm to 180 nm, while leading to only a minor increase in the crystallographic inclinations of the Ge islands from 0.34 deg to 0.54 deg. With finite element method simulations, we find that the small residual strain in Ge originates during the cool-down from growth to room temperature because of thermal expansion coefficient mismatch between Ge and SiO2. A tensile force develops along the [001] axis of the Ge pillar whose faster shrinkage to the room temperature volume is restricted by the oversized surface island. [ABSTRACT FROM AUTHOR]

Si/C composite material is a promising anode material for next-generation lithium-ion batteries due to its high capacity. However, it also exhibits significant initial capacity loss in a full cell due to the unstable SEI. To compensate for the loss of Li inventory, a pre-lithiation reagent, Li5FeO4 (LFO), is incorporated into the LiNi0.85Co0.12Mn0.03O2 (NCM85E) cathode for electrochemical evaluation. The results show that with the addition of LFO, the initial discharge capacity of SiC950/NCM85E full cells can increase from 151.0 mA h g−1 to 193.4 mA h g−1 by 28.1% with a high cathode loading up to about 20 mg cm−2. After 200 cycles, the specific capacity also increased by 25.1%. [ABSTRACT FROM AUTHOR]

Pb‐free perovskites are novel compounds that are currently being studied, essentially for their photovoltaic applications. In this article, the hybrid organic–inorganic perovskite for photovoltaic applications is studied. In fact, the structural and electronic properties of the perovskite FABI3 (B = Sn, Ge, or Pb and FA = formamidinium: CH(NH2)2) applying the density functional theory method executed in the Quantum Espresso framework are studied and discussed. The band structures of these perovskites have been presented; it is shown that these perovskites have a semiconductor nature, with a bandgap value of 1.36 eV for FASnI3, 1.72 eV for FAGeI3, and 1.61 eV for FAPbI3. Also, the density of states and partial density of states have been presented and discussed for each of these materials. Indeed, the structural properties of these perovskites are investigated and demonstrated that the optimized value of the lattice parameter is 6.35 Å for the FASnI3, while for the FAGeI3, this value is 6.3 Å and 6.5 Å for FAPbI3. Moreover, the impact of the lattice parameter on the bandgap value of FABI3 (B = Sn, Ge, or Pb) has been investigated, and it has been demonstrated that as the lattice parameter increases, the bandgap increases. The results of this work can be utilized as a guideline for the development of new efficient, lead‐free perovskite devices, including tandem solar cells. [ABSTRACT FROM AUTHOR]

The effects of Si addition on the microstructures and properties of CoCrNi medium-entropy alloy (MEA) were systematically investigated. The CrCoNiSix MEA possesses a single face-centered cubic (FCC) phase when x is less than 0.3 and promotes solution strengthening, while the crystal structure shows a transition to the FCC+σ phase structure when x = 0.4 and the volume fraction of the σ phase increases with a microstructure evolution as the Si content increases. The Orowan mechanism from σ precipitation effectively enhances the strength, hardness, and stain hardening of CrCoNiSix MEA, which also exhibits superior hardness at high temperatures. Furthermore, a large amount of σ phase decreases the wear resistance because of the transformation of the main wear mechanism from abrasion wear for σ-free CrCoNiSix MEA to adhesion wear for σ-contained CrCoNiSix MEA. This work contributes to the understanding of the effect of Si addition on FCC structured alloys and provides guidance for the development of novel Si-doped alloys. [ABSTRACT FROM AUTHOR]

The persistent use of plastics in chemical and industrial procedures has resulted in the contamination of the environment and human health via microplastics (MPs). This study investigates heavy metals, MP, pH, conductivity, and turbidity levels in the Nida River in Poland. The Nida River exhibited the existence of diverse coloured MPs in several physical forms, including fibres, fragments, pellets, and foams. Differences in the number of MPs were noted at five selected locations, with values ranging from 215 to 280 MPs per litre. The mean number of MPs observed was 245 ± 21 per litre. The study of water samples using a scanning electron microscope indicates the existence of various MPs. The morphological study of these MPs revealed patterns of degradation. The energy-dispersive X-ray examination indicates the existence of several elements, such as carbon, nitrogen, oxygen, sodium, magnesium, aluminium, silicon, phosphorus, and others. The water exhibited fluctuations in its levels of heavy metal content. The average zinc concentration in all samples was 96.86 ± 40.25 μg/L, which was the highest. It was followed by Pb 37.6 ± 31.9 μg/L concentration. The turbidity measurement was recorded as 46.38 ± 22.54, the pH level was 7.078 ± 0.33, and the conductivity value was determined to be 1338.8 ± 39.64. The HQ and HI values for adults and children in all age groups were less than one. The carcinogenic excess lifetime cancer risk (ELCR) exceeds the threshold value in most water samples. This study aims to fill the existing gap in understanding the precise measurement of MPs and heavy metals in freshwater sources in Poland. Health risk evaluations are the first step in developing pollution management, control, and water quality standards. Highlights: Various MPs including fibres, fragments, pellets, and foams, were discovered in the Nida River. An average of 245 ± 21 MPs per litre was measured. Zinc has the highest average concentration, 96.86 ± 40.25 μg/L. The HQ and HI values for adults and children in all age groups were less than one. [ABSTRACT FROM AUTHOR]

Development of high-performance cutting tool materials is one of the critical parameters enhancing the surface finishing of high-speed machined products. Ti(C,N)-based cermets reinforced with and without different contents of silicon nitride were designed and evaluated to satisfy the requirements. In fact, the effect of silicon nitride addition to Ti(C,N)-based cermet remains unclear. The purpose of this study is to investigate the influence of Si3N4 additive on microstructure, mechanical properties, and thermal stability of Ti(C,N)-based cermet cutting tools. In the present work, α -Si3N4 "grade SN-E10" was utilized with various fractions up to 6 wt.% in the designed cermets. A two-step reactive sintering process under vacuum was carried out for the green compact of Ti(C,N)-based cermet samples. The samples with 4 wt.% Si3N4 have an apparent solid density of about 6.75 g/cm3 (relative density of about 98 %); however, the cermet samples with 2 wt.% Si3N4 exhibit a superior fracture toughness of 10.82 MP a.m 1 / 2 and a traverse rupture strength of 1425.8 MPa. With an increase in the contents of Si3N4, the Vickers hardness and fracture toughness of Ti(C,N)-based cermets have an inverse behavior trend. The influence of Si3N4 addition on thermal stability is clarified to better understand the relationship between thermal stability and mechanical properties of Ti(C,N)-based cermets. [ABSTRACT FROM AUTHOR]

Zirconium alloys are used as a cladding material for fuel elements in nuclear reactors. In the case of severe accident conditions, the possible rapid oxidation of zirconium in steam or/and air may result in intense hydrogen generation and hydrogen–oxide mixture explosion. Advanced technologies for increasing the corrosion resistance of claddings are being investigated in two directions: (a) protective coatings on Zr alloys and (b) the use of new materials for claddings. Coatings with silicon may provide a more protective barrier than the ZrO2 films formed on an alloy cladding during nuclear plant operations. These coatings may also serve as a protective barrier during high-temperature accidents. The current work aimed at developing protective coatings with silicon on zirconium alloys. Multielemental Zr–Si–Cr coatings were formed on Zry-2 alloy using the physical vapor deposition (PVD) method. Long-term oxidation tests were carried out under the following conditions: 360°C/195 bar/63 days/water-simulating PWR water. Obtained results show the protective character of formed layers. The material in the form of silicon carbide grains covered with yttrium–aluminum garnet (SiC + YAG) was prepared using the sol–gel method. The formed powder is the main component for coating formation on Zr–1Nb alloy using the method of suspension plasma spraying (SPS). [ABSTRACT FROM AUTHOR]

Porous silicon structures are effective in trapping light due to the abundance of pores on their surface, finding widespread use in optical applications like photoelectric conversion, photon collection, and detection. We have successfully created micro-porous silicon with exceptionally high antireflection performance through electrochemical etching using different concentrations of silver catalysts. Results show that this germanium coated porous silicon structure has a smaller range of pore sizes, leading to a reduced reflectivity of 2.6 % under light radiation with wavelengths. To understand the antireflective mechanism further, we explored the surface reflectivity of porous silicon structures by coating the germanium metal on the porous structure. Importantly, germanium coated porous silicon structures with high surface quality and well-preserved pore integrity are identified as beneficial for achieving lower reflectivity in the incident light wavelength range of 300–1200 nm. These findings are significant for the design of porous silicon antireflective materials. [ABSTRACT FROM AUTHOR]

We investigated the reaction kinetics and initial chemical conditions in the production of silicon alloys, employing aluminum as the reductant for calcium silicate slag, to enhance process economics and scalability to industrial levels. The apparent kinetics and transient chemical conditions were studied by immersing solid aluminum into molten slag, allowing the reaction to proceed for varying durations without external agitation, before quenching the reaction for chemical and microscopic analyses of the resulting silicon alloy and slag. The majority of the conversion was observed within the first 15 s at 1650 °C, driven by significant chemical interactions and interfacial turbulence introduced upon aluminum immersion. For Al-SiO2 stoichiometries ranging from 0.5 to 1.2, the slag phase reaction conformed to first-order kinetics during the initial two minutes, when it approached equilibrium. The mass transfer coefficients for Al2O3 were estimated at 1–2 × 10−4 m/s, comparable to those for SiO2 and CaO. A constant mass transfer coefficient could not be established for stoichiometries of 1.6 and 2, as these deviated from the standard slag mass transfer relationship and did not adhere to established relationships. Despite near-complete reactions, alloy–slag mixing was extensive, decreasing with lower stoichiometry values. [ABSTRACT FROM AUTHOR]

A silicon nanoparticle–graphite nanosheet composite was prepared via a facile ball milling process for use as the anode for high-rate lithium-ion batteries. The size effect of Si nanoparticles on the structure and on the lithium-ion battery performance of the composite is evaluated. SEM and TEM analyses show a structural alteration of the composites from Si nanoparticle-surrounded graphite nanosheets to Si nanoparticle-embedded graphite nanosheets by decreasing the size of Si nanoparticles from 250 nm to 40 nm. The composites with finer Si nanoparticles provide an effective nanostructure containing encapsulated Si and free space. This structure facilitates the indirect exposure of Si to electrolyte and Si expansion during cycling, which leads to a stable solid–electrolyte interphase and elevated conductivity. An enhanced rate capability was obtained for the 40 nm Si nanoparticle–graphite nanosheet composite, delivering a specific capacity of 276 mAh g−1 at a current density of 1 C after 1000 cycles and a rate capacity of 205 mAh g−1 at 8 C. [ABSTRACT FROM AUTHOR]

With the development of the electronics industry, the requirements for chips are getting higher and higher, and thinner and thinner wafers are needed to meet the processing of chips. In this study, a model of the adhesion state of semiconductor wafers in the stacking–clamping process based on microarray adsorption was established, the composition adhesion was discussed, the microarrays of different materials and pressures were experimentally studied, and a molecular dynamics model was established. The molecular dynamics analysis showed that the adhesion force was only related to the type of atom, and the applied pressure did not change the adhesion force. According to the simulation results, the tangential adhesion between the metal and the wafer is greater than that between the ceramic and the wafer, the adsorption force between the aluminum–magnesium alloy and the silicon wafer is shown in the normal direction, and the repulsion force between other materials and the silicon wafer is shown in the normal direction. During the pressure process, the metal is in the elastic deformation stage between the metal and the wafer, the wafer is plastically deformed in the silicon carbide ceramic and wafer, and the wafer is elastically deformed in the alumina ceramic and wafer. In this paper, the adhesion between the substrate and the wafer is studied, a method of constructing microarrays to enhance adhesion is proposed, and the tangential deformation of the array unit under pressure is studied, which provides theoretical support for increasing the adhesion by constructing microarrays. [ABSTRACT FROM AUTHOR]

An improved sessile drop method was used to measure the dynamic nonreactive wetting behavior of different titanium concentrations interstitial-free molten steel on an alumina substrate at 1550 ºC, and the interfacial tension was also calculated by Young' equation based on the measured surface tension and the static contact angle compared to the previous sessile drop method. And the discrepancies were investigated by analyzing the interface layer between the melt and the alumina substrate with different oxygen partial pressures. Furthermore, it was discussed for the forces analysis of the dynamic contact angle for the improved sessile drop method and the interface layer reactive for the improved sessile drop method. The results demonstrate that the advancing angle, receding and static contact angles between the flowing melt and the solid substrate were quickly obtained by the improved sessile drop method. And the interfacial tension between molten steel and alumina substrate, which is 1428.71 and 1221.35 mN/m, respectively, with titanium concentrations of 280 ppm and 540 ppm for the improved sessile drop method, is higher than for the previous sessile drop method, which is 1245.56 and 719.01 mN/m, respectively. The low alloy interstitial-free molten steel and alumina substrate had formed an interface layer for the previous sessile drop method, and the thickness of the interface layer increased from 3.5 to 77.8 μm with a titanium concentration of 540 ppm as the oxygen partial pressure increased from 5.4 × 10−23 to 5.4 × 10−19 atm. The interface layer, which is composed of alloy compounds such as silicon, manganese and titanium oxides, is sensitive to the active alloy of interstitial-free molten steel and oxygen partial pressure. [ABSTRACT FROM AUTHOR]

Recently, silicon has been considered one of the preferred materials for the anodes of next-generation high-energy-density Li-ion batteries due to its advantages of high specific capacity, low working voltage, and abundant reserves. However, the huge volume change and poor electrical conductivity of silicon anodes during the lithiation and de-lithiation process seriously affect their practical application. Herein, honeycomb porous silicon is synthesized by a modified Stöber method and magnesium thermal reduction, which avoids using toxic gases (such as silane) in the traditional preparation of commercial nano-silicon. Moreover, the honeycomb porous structure can effectively alleviate the volume expansion during the charge/discharge process and agglomeration behavior of nano-silicon. Therefore, thanks to its unique structural merits, the honeycomb porous silicon anode is endowed with a reversible specific capacity of 824.1 mA h g−1 after 100 cycles at 0.5 A g−1 and 679.2 mA h g−1 even at an ultrahigh current density of 1.0 A g−1 after an extended cycling period of 200 cycles, which is almost twice that of commercial nano-silicon. More importantly, this finding offers promising advancements in designing silicon anodes in energy storage. [ABSTRACT FROM AUTHOR]

To clarify the evolution of thermal maturity and pore structure in continental organic-rich shales, calcareous shales of the Liaohe Basin (China) were pyrolyzed, and examined using Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), nitrogen sorption isotherms, and nuclear magnetic resonance (NMR) spectroscopy. The increase in Raman G-D band separation and decrease in Raman ID/IG ratio with increasing thermal maturity indicate that these parameters provide superior thermal maturity indicators. This is also confirmed by the good linear correlation of G-D band shifts and ID/IG with vitrinite reflectance (VR) and maximum temperature (Tmax), respectively. The relative detection accuracy (DA), sampling requirements (SR), sample preparation (SP), detection time (DT), and equipment requirement (ER) of VR, G-D band shifts, ID/IG, Tmax, FTIR, and XPS indicate that Raman analysis is a simple, quick, and robust method to evaluate thermal maturity. The moderate SR, complex SP, and long DT suggest that VR and Tmax are less widely applicable for characterizing thermal maturity. The FTIR and XPS techniques provide semi-quantitative maturity indicators with poor DA and high ER. Pores observed within organic matter and minerals under SEM indicate that an increase in thermal maturity not only affects the development of organic pores but is also beneficial for the formation of mineral dissolution pores, such as those formed during the transformation of Na0 95Ca016Al1 16Si2 84O8 to Na0 84Ca0 02Al1 02Si2 98O8, a process confirmed by XRD. The BET and NMR data also indicate that the development of pore structure is closely related to the evolution of thermal maturity in calcareous shale . During the initial stage, primary pores are filled by bitumen generated from kerogen; this leads to a decrease in transition pores, mesopores, and shale porosity, and reduced pore connectivity. Then, secondary nanoscale pores, transition pores, and mesopores increase with increasing thermal maturity. The peak in secondary porosity is consistent with the liquid hydrocarbon production rate peak, a process that increases shale porosity and leads to improved pore connectivity. The dissolution of minerals induced by organic acids may also contribute to this secondary porosity. With a further increase in thermal maturity, secondary porosity at the microscale is further developed, while transition pores and mesopores collapse, resulting in reduced pore connectivity. The poor pore connectivity that occurs at both low and high VR values may be more conducive to the preservation of shale oil and gas. This study is significant for research into the evolution of thermal maturity and pore structure in continental organic-rich shales. [ABSTRACT FROM AUTHOR]

Multi-level phase-change can not only increase the storage density of phase-change memory, but also has important applications in neuromorphic computing. However, its realization is still very challenging. Here, we study the phase-change behaviors of four bilayer films, Sb7Se3(x nm)/Ge50Te50(90 nm), with x = 30, 50, 70, and 100. The expected three-level phase change is not observed at all. Raman and XRD characterizations reveal the occurrence of interlayer coupling between Sb7Se3 and Ge50Te50 layers. De-coupling structure films, Sb7Se3(x nm)/Si(50 nm)/Ge50Te50(90 nm), are proposed and prepared, where the amorphous Si layer serves as de-coupling the interlayer coupling. Three-level phase change is observed in all de-coupling Sb7Se3(x nm)/Si(50 nm)/Ge50Te50(90 nm) films. Our works demonstrate the effect of interlayer coupling on multi-level phase-change, and the de-coupling idea provides a design way for multi-level phase-change materials. [ABSTRACT FROM AUTHOR]

Using silicon/reduced graphene oxide (Si/rGO) composites as lithium-ion battery (LIB) anodes can effectively buffer the volumetric expansion and shrinkage of Si. Herein, we designed and prepared Si/rGO-b with a sandwiched structure, formed by a duple combination of ammonia-modified silicon (m-Si) nanoparticles (NP) with graphene oxide (GO). In the first composite process of m-Si and GO, a core–shell structure of primal Si/rGO-b (p-Si/rGO-b) was formed. The amino groups on the m-Si surface can not only hybridize with the GO surface to fix the Si particles, but also form covalent chemical bonds with the remaining carboxyl groups of rGO to enhance the stability of the composite. During the electrochemical reaction, the oxygen on the m-Si surface reacts with lithium ions (Li+) to form Li2O, which is a component of the solid–electrolyte interphase (SEI) and is beneficial to buffering the volume expansion of Si. Then, the p-Si/rGO-b recombines with GO again to finally form a sandwiched structure of Si/rGO-b. Covalent chemical bonds are formed between the rGO layers to tightly fix the p-Si/rGO-b, and the conductive network formed by the reintroduced rGO improves the conductivity of the Si/rGO-b composite. When used as an electrode, the Si/rGO-b composite exhibits excellent cycling performance (operated stably for more than 800 cycles at a high-capacity retention rate of 82.4%) and a superior rate capability (300 mA h/g at 5 A/g). After cycling, tiny cracks formed in some areas of the electrode surface, with an expansion rate of only 27.4%. The duple combination of rGO and the unique sandwiched structure presented here demonstrate great effectiveness in improving the electrochemical performance of alloy-type anodes. [ABSTRACT FROM AUTHOR]

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This paper presents a practical approach to the production of certified reference materials (CRMs) for ferrosilicon magnesium alloys. These new CRMs are predicted to be used in fast X-ray fluorescence spectrometry (XRF) analysis, which does not require sample digestion and does not result in the production of acidic sewage and emissions, contrary to the classical and instrumental techniques currently used in laboratories. Four new certified reference materials (CRMs) were developed to fill the gap in the reference materials market and ensure fast and traceable analyses. The materials were produced with an industrial process and then homogenized and mixed to achieve the required compositions and level of homogeneity. The homogeneity was determined using specially developed analytical methods and confirmed statistically by ANOVA. Additionally, the results of the tests show the short- and long-term stabilities of the new materials. The certified values for specific element contents were determined in interlaboratory tests. All results were assessed statistically for outliers. The results from three or more independent and different analytical methods were used for the calculations. In parallel homogeneity, the stability, and characterization standard uncertainties were calculated and used in the estimation of the final expanded uncertainties of the certified values. Finally, four new CRMs were assisted with the proper certificates according to ISO standards. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate the catalytic activity of microporous Silico Alumino Phosphate (SAPOs) crystals for the assisted plasma synthesis of ammonia. SAPOs can aid as effective catalysts for the synthesis of ammonia via non-thermal plasma using an atmospheric dielectric barrier discharge (DBD) reactor. We studied three prototypical zeolites having crystallographic limiting pore apertures of 3.4 Å (SAPO-56), 3.8 Å (SAPO-34) and 3.9 Å (SAPO-11). We describe a fundamental insight on the effect of the Si/Al ratio and the pore size on ammonia synthesis rate for the different SAPOs. The resultant SAPO-11 displayed ammonia synthesis rates as high as 0.19 micromoles NH3/ min m2 at 20 watts, approximately 1.5 times better compared to other SAPOs. The results indicate that ammonia synthesis is promoted by a lower Si/Al ratio (< 0.25) of the SAPO. Moreover, we observed that SAPO-34 (3.8 Å) and SAPO-11 (3.9 Å) which allow diffusion of N2 (3.6 Å) in to the pores lead to a higher ammonia yield. The lower intensity observed in optical emission spectroscopy (OES) for SAPO-34 suggests the diffusion of plasma activated species onto the surface and the pores. Proving the importance of porosity in plasma catalysis. [ABSTRACT FROM AUTHOR]

Recently, surface‐hopping ab initio molecular dynamics (SH‐AIMD) simulations have come to be used to discuss the mechanisms and dynamics of excited‐state chemical reactions, including internal conversion and intersystem crossing. In dynamics simulations involving intersystem crossing, there are two potential energy surfaces (PESs) governing the motion of nuclei: PES in a spin‐pure state and PES in a spin‐mixed state. The former gives wrong results for molecular systems with large spin‐orbit coupling (SOC), while the latter requires a potential gradient that includes a change in SOC at each point, making the computational cost very high. In this study, we systematically investigate the extent to which the magnitude of SOC affects the results of the spin‐pure state‐based dynamics simulations for the hydride MH2 (M = Si, Ge, Sn, Pb) by performing SH‐AIMD simulations based on spin‐pure and spin‐mixed states. It is clearly shown that spin‐mixed state PESs are indispensable for the dynamics simulation of intersystem crossing in systems containing elements Sn and Pb from the fifth period onward. Furthermore, in addition to the widely used Tully's fewest switches (TFS) algorithm, the Zhu‐Nakamura (ZN) global switching algorithm, which is computationally less expensive, is applied to SH for comparison. The results from TFS‐ and ZN‐SH‐AIMD methods are in qualitative agreement, suggesting that the less expensive ZN‐SH‐AIMD can be successfully utilized to investigate the dynamics of photochemical reactions based on quantum chemical calculations. [ABSTRACT FROM AUTHOR]

Suppression of threading dislocations (TDs) in thin germanium (Ge) layers grown on silicon (Si) substrates has been critical for realizing high-performance Si-based optoelectronic and electronic devices. An advanced growth strategy is desired to minimize the TD density within a thin Ge buffer layer in Ge-on-Si systems. In this work, we investigate the impact of P dopants in 500-nm thin Ge layers, with doping concentrations from 1 to 50 × 1018 cm−3. The introduction of P dopants has efficiently promoted TD reduction, whose potential mechanism has been explored by comparing it to the well-established Sb-doped Ge-on-Si system. P and Sb dopants reveal different defect-suppression mechanisms in Ge-on-Si samples, inspiring a novel co-doping technique by exploiting the advantages of both dopants. The surface TDD of the Ge buffer has been further reduced by the co-doping technique to the order of 107 cm−2 with a thin Ge layer (of only 500 nm), which could provide a high-quality platform for high-performance Si-based semiconductor devices. [ABSTRACT FROM AUTHOR]

Novel zinc-blende (zb) group-IV binary XC and ternary XxY1−xC alloys (X, Y ≡ Si, Ge, and Sn) have recently gained scientific and technological interest as promising alternatives to silicon for high-temperature, high-power optoelectronics, gas sensing and photovoltaic applications. Despite numerous efforts made to simulate the structural, electronic, and dynamical properties of binary materials, no vibrational and/or thermodynamic studies exist for the ternary alloys. By adopting a realistic rigid-ion-model (RIM), we have reported methodical calculations to comprehend the lattice dynamics and thermodynamic traits of both binary and ternary compounds. With appropriate interatomic force constants (IFCs) of XC at ambient pressure, the study of phonon dispersions ω j q → offered positive values of acoustic modes in the entire Brillouin zone (BZ)—implying their structural stability. For XxY1−xC, we have used Green's function (GF) theory in the virtual crystal approximation to calculate composition x, dependent ω j q → and one phonon density of states g ω . With no additional IFCs, the RIM GF approach has provided complete ω j q → in the crystallographic directions for both optical and acoustical phonon branches. In quasi-harmonic approximation, the theory predicted thermodynamic characteristics (e.g., Debye temperature ΘD(T) and specific heat Cv(T)) for XxY1−xC alloys. Unlike SiC, the GeC, SnC and GexSn1−xC materials have exhibited weak IFCs with low [high] values of ΘD(T) [Cv(T)]. We feel that the latter materials may not be suitable as fuel-cladding layers in nuclear reactors and high-temperature applications. However, the XC and XxY1−xC can still be used to design multi-quantum well or superlattice-based micro-/nano devices for different strategic and civilian application needs. [ABSTRACT FROM AUTHOR]

In this paper, the applicability of dual material stacked gate-oxide-Pocket doped-hetero-junction tunnel field effect transistor (DMSGO-PD-HTFET) for low power switching and radio frequency (RF) applications is investigated. In this context, gate workfunction engineering, the stacked-gate-oxide ($$Si{O_2}$$ Si O 2 + $$Hf{O_2}$$ Hf O 2 ) approach, and asymmetrical doping at the P+ source ($$S{i_{1 - X}}G{e_X}$$ S i 1 − X G e X ) and N+ drain regions are considered. N+ pocket at source-channel interface implements DMSGO-PD-HTFET and improves interband tunnelling rate. This research aims to improve the device's switching ratio ($${I_{ON}}$$ I ON / $${I_{OFF}}$$ I OFF ), average subthreshold swing ($$S{S_{Avg}}$$ S S Avg ), and radio frequency (RF) performance. For this, the control gate work function, mole fraction (X), pocket thickness, and doping concentration are optimised. Next, the DC, analog/RF and linearity figure of merits of the proposed device is analysed and the performance is compared with conventional all-silicon dual-material stack gate oxide tunnel field effect transistor (DMSGO-TFET) and dual-material stacked gate oxide-hetero-junction tunnel field effect transistor (DMSGO-HTFET) with $$S{i_{1 - X}}G{e_X}$$ S i 1 − X G e X source using technology computer-aided design (TCAD) device simulator. Based on the comparative analysis, the optimised design with $$S{i_{0.6}}G{e_{0.4}}$$ S i 0.6 G e 0.4 exhibits an average subthreshold swing ($$S{S_{Avg}}$$ S S Avg ) of 28.8 mV/decade, switching ratio ($${I_{ON}}$$ I ON / $${I_{OFF}}$$ I OFF ) of 2 × 1012, cut-off frequency ($${f_T}$$ f T ) of 216 (GHz), and other significant improvements in analog/RF and linearity performance parameters. The proposed device is therefore suitable for switching and RF applications. [ABSTRACT FROM AUTHOR]

The article presents the results of studies on the use of the high-silicon phosphorites (51,8 % of Ca3(PO4)2, 25,6 % of SiO2) for the co-production of ferrosilicon, calcium carbide and gaseous phosphorus. The studies included the electric smelting a charge in an arc furnace and using the second-order rotatable designs. The conditions of producing FeSi45 ferrosilicon (51,2-54,2 % of coke, 12,5-18,4 % of steel shavings) and FeSi25 ferrosilicon (53-58 % of coke, 39,7- 40 % of steel shavings) with extraction of 65-67,8 % of silicon into the alloy were determined. The second product of the process is technical calcium carbide with a capacity of 129-167 l/kg, in which from 44,8 to 64,1 % of calcium is extracted. At least 99,3 % of phosphorus during the electric smelting is sublimated. [ABSTRACT FROM AUTHOR]

The optoelectronic properties of prototypal Telluride amorphous phase-change materials (GeTe and Ge2Sb2Te5) are investigated from ab initio molecular dynamics simulations. Local tetrahedral germanium geometries are identified from topological angular constraint counting and this permits to relate exactly their contribution to targeted properties. The analysis of our computation reveals that the dominant population of tetrahedral Ge contributes to the tail of the valence and conduction band but with an increased electronic localization for the latter, whereas residual (essentially octahedral) geometries induce an overall constant localization at E > EF except close to the Fermi gap, where p electrons are largely delocalized. The detailed calculation of the atomic dipoles in the amorphous state indicates that tetrahedral Ge leads to lower momenta, especially in a-GeTe, and corresponding Ge-based correlations withWannier centers also indicate the dual nature of the local geometries. These features which drive optical and dielectric contrast exemplify the unique properties of phase-change materials, and represent an obvious breakdown of the well-known Zachariasen rule stating that the short-range order is similar in crystals and glasses. [ABSTRACT FROM AUTHOR]