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Looking back at seven decades of highly extensive application in the semiconductor industry, silicon and its native oxide SiO2 are still at the heart of several technological developments. Recently, the fabrication of ultra-thin oxide layers has become essential for keeping up with trends in the down-scaling of nanoelectronic devices and for the realization of novel device technologies. With this comes a need for better understanding of the atomic configuration at the Si/SiO2 interface. Classical force fields offer flexible application and relatively low computational costs, however, suffer from limited accuracy. Ab initio methods give much better results but are extremely costly. Machine learning force fields (MLFF) offer the possibility to combine the benefits of both worlds. We train a MLFF for the simulation of the dry thermal oxidation process of a Si substrate. The training data are generated by density functional theory calculations. The obtained structures are in line with ab initio simulations and with experimental observations. Compared to a classical force field, the most recent reactive force field, the resulting configurations are vastly improved. Our potential is publicly available in an open-access repository. [ABSTRACT FROM AUTHOR]

Two-photon absorption in indirect gap semiconductors is a frequently encountered, but not well-understood phenomenon. To address this, the real-density matrix approach is applied to describe two-photon absorption in silicon through the excitonic response to the interacting fields. This approach produces an analytical expression for the dispersion of the two-photon absorption coefficient for indirect-gap materials and can be used to explain trends in reported experimental data for bulk silicon both old and new with minimal fitting. [ABSTRACT FROM AUTHOR]

Electrical properties of defects produced in strongly bismuth-doped silicon by 15 MeV protons are investigated in detail. Electrical measurements on irradiated samples by means of the van der Pauw technique are conducted over a wide temperature range of 20–300 K to furnish information on radiation-produced complexes. It is shown that the properties of the dominant bismuth-related defects are the same as earlier found in the electron-irradiated material. These complexes are tentatively identified as bismuth–vacancy pairs being deep donors. Their atomic configuration appears to be radically different from what is known about similar vacancy-related defects with other group-V impurities. These bismuth-related pairs are stable up to T ≈ 300 °C. Some special features of defect formation and annealing processes of radiation defects in bismuth-doped silicon subjected to electron and proton irradiation are discussed. This information may be of advantage in modeling impurity-related complexes containing oversized impurity atoms in silicon. [ABSTRACT FROM AUTHOR]

Atomistic simulations often rely on interatomic potentials to access greater time and length scales than those accessible to first-principles methods, such as density functional theory. However, since a parameterized potential typically cannot reproduce the true potential energy surface of a given system, we should expect a decrease in accuracy and increase in error in quantities of interest calculated from these simulations. Quantifying the uncertainty on the outputs of atomistic simulations is thus an important, necessary step so that there is confidence in the results and available metrics to explore improvements in said simulations. Here, we address this research question by forming ensembles of atomic cluster expansion potentials, and using conformal prediction with ab initio training data to provide meaningful, calibrated error bars on several quantities of interest for silicon: the bulk modulus, elastic constants, relaxed vacancy formation energy, and the vacancy migration barrier. We evaluate the effects on uncertainty bounds using a range of different potentials and training sets. [ABSTRACT FROM AUTHOR]

Silicon, renowned for its remarkable energy density, has emerged as a focal point in the pursuit of high-energy storage solutions for the next generation. Nevertheless, silicon electrodes are known to undergo significant volume expansion during the insertion of lithium ions, leading to structural deformation and the development of internal stresses, and causing a rapid decline in battery capacity and overall lifespan. To gain deeper insights into the intricacies of charge rate effects, this study employs a combination of in situ measurements and computational modeling to elucidate the cyclic performance of composite silicon electrodes. The findings derived from the established model and curvature measurement system unveil the substantial alterations in stress and deformation as a consequence of varying charge rates. Notably, the active layer experiences compressive forces that diminish as the charge rate decreases. At a charge rate of 0.2, the active layer endures a maximum stress of 89.145 MPa, providing a comprehensive explanation for the observed deterioration in cycling performance at higher charge rates. This study not only establishes a fundamental basis for subsequent stress analyses of silicon electrodes but also lays a solid foundation for further exploration of the impact of charge rates on composite silicon electrodes. [ABSTRACT FROM AUTHOR]

Conductive-bridge random access memory can be used as a physical reservoir for temporal learning in reservoir computing owing to its volatile nature. Herein, a scaled Cu/HfOx/n+-Si memristor was fabricated and characterized for reservoir computing. The scaled, silicon nanofin bottom electrode formation is verified by scanning electron and transmission electron microscopy. The scaled device shows better cycle-to-cycle switching variability characteristics compared with those of large-sized cells. In addition, synaptic characteristics such as conductance changes due to pulses, paired-pulse facilitation, and excitatory postsynaptic currents are confirmed in the scaled memristor. High-pattern accuracy is demonstrated by deep neural networks applied in neuromorphic systems in conjunction with the use of the Modified National Institute of Standards and Technology database. Furthermore, a reservoir computing system is introduced with six different states attained by adjusting the amplitude of the input pulse. Finally, high-performance and efficient volatile reservoir computing in the scaled device is demonstrated by conductance control and system-level reservoir computing simulations. [ABSTRACT FROM AUTHOR]

The effects of carbon in heavily phosphorus-doped Czochralski (HP-Cz) silicon (Si) substrates, with the concentrations across an order of magnitude from 1016 to 1017 cm−3, on the out-diffusion of phosphorus impurities within n/n+ epitaxial Si (Epi-Si) wafers have been investigated. It is found that the increase in the carbon concentration ([C]) from 1.0 × 1016 to 1.0 × 1017 cm−3 leads to the enhanced phosphorus out-diffusion within the n/n+ Epi-Si wafer when subjected to anneal at 1100 °C in an N2 or an O2 ambient or to anneal at 1150 °C in an N2 ambient, but hardly affects the phosphorus out-diffusion within the n/n+ Epi-Si wafer when subjected to anneal at 1150 °C in an O2 ambient. Based on the density functional theory calculations, it is derived that the increase in the [C] from 1.0 × 1016 to 1.0 × 1017 cm−3 in the HP-Cz Si substrate results in a significantly increased thermal equilibrium concentration of self-interstitial silicon (SiI) atoms at 1100 or 1150 °C, which, in turn, leads to the increased concentration of the SiI atoms that out-diffuse from the substrate to the epitaxial layer because the SiI atoms diffuse extremely fast in Si. Such a carbon-induced increase in the concentration of SiI atoms is believed to be responsible for the aforementioned enhanced phosphorus out-diffusion, which is predominantly dictated by the interstitialcy mechanism. In the case of anneal in the O2 ambient at sufficiently high temperatures such as 1150 °C, a large number of excessive SiI atoms injected into the Epi-Si wafer substantially mask the carbon enhancement effect on the phosphorus out-diffusion. Of technological significance, it is deduced that the [C] should be not higher than 1.0 × 1016 cm−3 in the HP-Cz Si wafers as the substrates of n/n+ Epi-Si wafers used for power devices. [ABSTRACT FROM AUTHOR]

The study of light-emitting defects in silicon created by ion implantation has gained renewed interest with the development of quantum optical devices. Improving techniques for creating and optimizing these defects remains a major focus. This work presents a comprehensive analysis of a photoluminescence line at a wavelength of 1240 nm (1 eV) caused by defects arising from the ion irradiation of the SiO2/Si system and subsequent thermal annealing. It is assumed that this emission is due to the formation of defect complexes WM with trigonal symmetry similar to the well-known W-centers. A distinctive feature of these defects is their thermal resistance up to temperatures of 800 °C and less pronounced temperature quenching compared to the W-line. The difference in the properties of these defect centers and W-centers can be explained by their different defect environments, resulting from the larger spatial separation between vacancies and interstitial atoms diffusing from the irradiated layer. This, in turn, is associated with the difference in the distribution of primary radiation defects during irradiation of the SiO2/Si system and silicon not covered with a SiO2 film. The patterns of changes in the WM line depending on various factors, such as the thickness of the SiO2 film, type of conductivity and impurity concentration in the original silicon, irradiation parameters, and annealing regimes, is studied and explained in detail. These findings demonstrate the benefits of this new approach when compared to previous methods. [ABSTRACT FROM AUTHOR]

We propose a main mechanism of large valley splitting experimentally observed at the interface of buried oxide (BOX)/silicon-on-insulator (SOI) structures. Silicon metal-oxide-semiconductor field effect transistors fabricated on a SIMOX (001) substrate, which is a kind of the SOI substrate, that is annealed at high temperatures for a long time are known to exhibit large valley splitting, but the origin of this splitting has long been unknown. Extended zone effective-mass approximation predicts that strain significantly affects valley splitting. In this study, we analyzed valley splitting based on this theory and found that the shear strain along [110] of approximately 5% near the BOX interface is a promising source for large valley splitting. [ABSTRACT FROM AUTHOR]

A comprehensive quantitative root cause study of defect evolution leading to memory window closure from a charge balance and charge trapping perspective throughout all phases of a Si channel Hf0.5Zr0.5O2 (HZO) ferroelectric field-effect-transistor (FEFET) is reported. Starting with the first write pulse, an excessive SiO2 interlayer field is revealed that triggers the creation of defect levels Dit in excess of 1015 cm−2 eV−1 at the HZO–SiO2 interface screening ferroelectric (FE) polarization while enabling FE switching. Under subsequent early bipolar fatigue cycling (up to 104 cycles), defect creation commences at the SiO2–Si interface due to the high injected hole fluence (0.39 C/m2) during each stress pulse causing negative bias instability (NBI), which shifts the threshold voltage of the erase state VT,ERS by −0.3 V with accrual of permanently captured charge Nit of up to +5 × 10−3 C/m2 (3 × 1012 cm−2). Subsequently, Nit NBI generation at the SiO2–Si interface accelerates reaching levels of +7 × 10−2 C/m2, locking both FEFET program and erase drain current vs gate–source-voltage (ID–VGS) characteristics in the FEFET on-state inducing memory window closure at 105 cycles while FE switching (switched polarization Psw = 0.34 C/m2) remains essentially intact. These findings guide the down-selection toward suitable semiconductor/FE systems for charge balanced, reliable, and high endurance FEFETs. [ABSTRACT FROM AUTHOR]

In this work, we present a comprehensive re-evaluation of the iron–gallium (FeGa) recombination parameters in silicon using injection-dependent lifetime spectroscopy (IDLS). Ga-doped silicon wafers (of varying resistivities) with precise concentrations of intentional iron contamination in the silicon wafer bulk, through ion implantation and distribution, were used. The presence of interstitial Fei and FeGa, and their lifetime-limiting effects in these silicon wafers, were confirmed through measuring the effective minority carrier lifetime changes during the conditions that are known to cause FeGa dissociation and association. The presence of Fe was also confirmed by deep-level transient spectroscopy. To ensure accurate IDLS analysis of the FeGa defect in silicon, a lifetime linearization scheme was employed to effectively filter out interference by other defects. Error analysis was employed to find the combination of defect parameters that best fit the experimental data and to ascertain the range of uncertainty associated with the IDLS best-fit results. The optimal fitting of the experimental IDLS by Shockley–Read–Hall statistics produced an electron capture cross section σ n = 2.3 × 10 − 14 c m 2 , hole capture cross section σ p = 1.1 × 10 − 14 c m 2 , and a trap energy level E t = E V + 0.2 − 0.01 + 0.02 eV for the FeGa defect in silicon. The extracted defect parameters are also verified by experimentally measuring the crossover point of Fei and FeGa lifetime curves. [ABSTRACT FROM AUTHOR]

Hyperdoped silicon is a promising material for near-infrared light detection, but to date, the device efficiency has been limited. To optimize photodetectors based on this material that operate at room temperature, we present a detailed study on the electrical nature of gold-hyperdoped silicon formed via ion implantation and pulsed-laser melting (PLM). After PLM processing, oxygen-rich and gold-rich surface layers were identified and a wet etch process was developed to remove them. Resistivity and Hall effect measurements were performed at various stages of device processing. The underlying gold-hyperdoped silicon was found to be semi-insulating, regardless of whether the surface gold was removed by etching or not. We propose a Fermi level pinning model to describe the band bending of the transformed surface layer and propose a promising device architecture for efficient Au-hyperdoped Si photodetectors. [ABSTRACT FROM AUTHOR]

Modulation doping of silicon has great potential for miniaturization, surface passivation, and third generation photovoltaics (PV). At a modulation-doped silicon surface, we observe the formation of a 2D hole layer at the silicon surface at low temperatures by means of photoluminescence (PL) measurements. A line shape analysis of band–band and hot luminescence reveals the hole density (which is equal to the modulation-doped acceptor density). A high excitation intensity leads to a Fermi edge singularity of the band–band and hot PL emission. While the 2D layer can be characterized by the observed luminescence, the spectral region of twice the bandgap is fully dominated by emission from this surface layer, impeding the measurement of bulk hot luminescence, e.g., from Auger electrons or from nonthermalized carriers in a hot carrier PV device. [ABSTRACT FROM AUTHOR]

Excess minority carriers create boron-related recombination centers that degrade the efficiency of the non-particle-irradiated silicon solar cells. However, the carrier-induced reactions among the radiation-induced defects are poorly understood for devices exposed to particle radiation. This study investigates the structure, electronic properties, formation and annihilation mechanisms, and diffusion dynamics of the carrier-induced defects in particle-irradiated boron-doped silicon using density-functional modeling and junction spectroscopy. By revisiting the ground-state structures of the boron-di-interstitial clusters (B I 2), we find that the calculated acceptor and donor levels of such defects agree well quantitatively with the carrier-induced deep-level transient spectroscopy (DLTS) hole emission signatures at 0.43 and 0.53 eV above the valence band edge (E v), respectively. We also find that the formation of B I 2 is thermally activated by an energy of 0.50 eV, which we explain theoretically by the reduction of the migration barrier of mono-interstitials to 0.53 eV in the presence of excess minority carriers. Moreover, we discover that the B I 2 are potentially mobile with a migration barrier of 1.18 eV, contrary to the present understanding. [ABSTRACT FROM AUTHOR]

Recently, Chiloyan et al. [Appl. Phys. Lett. 116, 163102 (2020)] have reported that phonon transport could exceed bulk heat conduction if low-frequency phonons with long mean free path (MFP) remain in the nonthermal regime in silicon. To gain a better understanding of their findings, we investigated the effects of temperature-induced anharmonicity on both Landau–Rumer damping and Akhiezer damping, including polarization. To do this, we follow a rigorous procedure for calculating the Akhiezer model and use phonon kinetic theory based on the Boltzmann transport equation. Consequently, we find that in the Akhiezer regime, the longitudinal acoustic phonon modes (LA) are strongly suppressed by phonon anharmonicity compared to the transverse acoustic phonon modes. Therefore, the low-frequency phonons with a long MFP of LA can help to exceed bulk heat conduction if they remain in the regime of nonthermal phonon transport where there are no appreciable scatterings with other phonons. It is also shown that Akhiezer damping eliminates thermal conductivity by 16.8% at 500 K, which is higher than the observed reduction (12.6%) at 300 K in silicon, uncovering a novel regime where the Akhiezer damping, previously deemed insignificant in the thermal conduction of bulk silicon, becomes crucial. [ABSTRACT FROM AUTHOR]

Precise and reproducible current generation is the key to realizing quantum current standards in metrology. A promising candidate is a tunable-barrier single-charge pump, which can accurately transfer single charges one by one with an error rate below the ppm level. Although several measurements have shown such levels of accuracy, it is necessary to further pursue the possibility of high-precision operation toward reproducible generation of the pumping current in many devices. Here, we investigated silicon single-hole pumps, which may have the potential to outperform single-electron pumps because of the heavy effective mass of holes. Measurements on the temperature dependence of the current generated by the single-hole pump revealed that the tunnel barrier had high energy selectivity, which is a critical parameter for high-accuracy operation. In addition, we applied the dynamic gate-compensation technique to the single-hole pump and confirmed that it yielded a further performance improvement. Finally, we demonstrated gigahertz operation of a single-hole pump in which the estimated lower bound of the pump error rate was around 0.01 ppm. These results imply that single-hole pumps in silicon are capable of high-accuracy, high-speed, and stable single-charge pumping in metrological and quantum-device applications. [ABSTRACT FROM AUTHOR]

Spin qubit systems are one of the promising candidates for quantum computing. The quantum dot (QD) arrays are intensively investigated by many researchers. Because the energy-difference between the up-spin and down-spin states is very small, the detection of the qubit state is of prime importance in this field. Moreover, many wires are required to control qubit systems. Therefore, the integration of qubits and wires is also an important issue. In this study, the measurement process of QD arrays is theoretically investigated using resonant tunneling, controlled by a conventional transistor. It is shown that the number of possible measurements during coherence time can exceed a hundred under the backaction of the measurements owing to the nonlinear characteristics of resonant tunneling. It is also discussed to read out the measurement results by the conventional transistor. [ABSTRACT FROM AUTHOR]

Abstract: Optically active quantum defects play an important role in quantum sensing, computing and communication. The electronic structure and the single-particle energy levels of these quantum defects in the semiconducting host have been used to understand their optoelectronic properties. Optical excitations that are central for their initialization and readout are linked to transitions between occupied and unoccupied single-particle states. It is commonly assumed that only quantum defects introducing levels well within the band gap and far from the band edges are of interest for quantum technologies as they mimic an isolated atom embedded in the host. In this perspective, we contradict this common assumption and show that optically active defects with energy levels close to the band edges can display similar properties. We highlight quantum defects that are excited through transitions to or from a band-like level (bound exciton) such as the T center and Se S i + in silicon. We also present how defects such as the silicon split-vacancy in diamond can involve transitions between localized levels that are above the conduction band or below the valence band. Loosening the commonly assumed requirement on the electronic structure of quantum defects offers opportunities in quantum defects design and discovery especially in smaller band gap hosts such as silicon. We discuss the challenges in terms of operating temperature for photoluminescence or radiative lifetime in this regime. We also highlight how these alternative type of defects bring their own needs in terms of theoretical developments and fundamental understanding. This perspective clarifies the electronic structure requirement for quantum defects and will facilitate the identification and design of new color centers for quantum applications especially driven by first principles computations.

Heavily phosphorus-doped Czochralski (HP-CZ) silicon is an important substrate material for manufacturing power electronic devices. The high concentration of phosphorus impurities may be supersaturated during the crystal growth of HP-CZ silicon or device manufacturing. Thus, understanding phosphorus precipitation in HP-CZ silicon is of technological significance. Herein, a panoramic view of phosphorus precipitation in HP-CZ silicon is presented in terms of crystallography, thermodynamics, and kinetics. It is found that the orthorhombic SiP precipitates can form during the crystal growth of HP-CZ silicon and also during the post-anneals of HP-CZ silicon at 450–1050 °C. Along with increasing annealing temperature, the formed SiP precipitates tend to adopt the platelet, polyhedron, and sphere-like shapes. Moreover, the excess point defects, i.e., silicon self-interstitials and vacancies, are found to affect phosphorus precipitation occurring in the low and high temperature regimes in different ways. In light of the kinetics of phosphorus precipitation at different temperatures, it is deduced that phosphorus precipitation follows a growth law in compliant with Ham's theory to a large extent. As an important output of this work, the temperature-dependent phosphorus solubilities in the dislocation-free silicon, which have been hardly acquired previously, are derived on the basis of investigating phosphorus precipitation in a set of HP-CZ silicon wafers with different phosphorus concentrations. Moreover, the derived solvus line for the phosphorus impurities in silicon could be a beneficial supplement to the existing phase diagram of the Si–P binary system in the extremely silicon-rich corner. [ABSTRACT FROM AUTHOR]

In an optically excited semiconductor micromechanical structure, photogenerated carriers (plasma waves) can produce elastic deformations (local strains and stresses)–plasmaelastic (PE) deformations. On the other hand, the generation of excess carriers will produce heat due to carrier thermalization and recombination processes. The generated heat can produce other elastic deformations–thermoelastic (TE) deformations. For these two components of elastic deformation, it is possible to consider two types of elastic displacements (two mods of elastic vibrations): elastic expanding and elastic bending. A theoretical model of the photoacoustic (PA) signal for optically excited Si membranes is given, which includes thermal diffusion (TD), TE, and PE mechanisms, in order to study elastic expansion and bending. The relations for the PA amplitude and the phase of elastic expanding and bending in the excited membrane are derived. Analysis of the PA signal indicates that the TD component is dominant for all thicknesses and practically the entire range of observed frequencies. The calculated PA amplitude and phase spectra show that the PA elastic expanding component has a significant influence on the total PA signal at low frequencies. On the other side, the calculated PA spectra show that the PA elastic bending component has a significant influence on the total PA signal at high frequencies. Experimental PA signals of Si membranes were measured using the sample-gas-microphone detection technique with a transmission configuration in relation to the modulation frequency of the optical excitation for different membrane thicknesses. The experimental PA spectra were compared with the theoretical ones. [ABSTRACT FROM AUTHOR]

The sensitivity and responsiveness of living cells to environmental changes are enabled by dynamic protein structures, inspiring efforts to construct artificial supramolecular protein assemblies. However, despite their sophisticated structures, designed protein assemblies have yet to be incorporated into macroscale devices for real-life applications. We report a 2D crystalline protein assembly of C98/E57/E66L-rhamnulose-1-phosphate aldolase (CEERhuA) that selectively blocks or passes molecular species when exposed to a chemical trigger. CEERhuA crystals are engineered via cobalt(II) coordination bonds to undergo a coherent conformational change from a closed state (pore dimensions

The current manuscript focuses on the photo-thermoelastic interactions in a rotating plate with a porous structure and temperature-dependent properties. The analysis is performed using the dual phase lag theory and by considering a two-dimensional isotropic homogeneous plate. The upper surface of the plate experiences the application of a mechanical source, while the lower surface of the plate is insulated thermally. The application of the normal mode technique enables the derivation of analytical expressions for various field variables such as displacement, stress, change in volume fraction field, carrier density and temperature within the physical domain. Numerical computations are performed for a plate composed of silicon material and the results are represented graphically with the support of MATLAB software to demonstrate the consistency of the obtained results. To outline the influences of rotation, photothermal transport process, temperature-dependent properties and void parameters on the physical fields, certain collations are presented. Some specific cases of interest have also been deducted. [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]

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Here, a combination of dopamine self‐polymerization and epoxy modified SiO2 (M‐SiO2) grafting was proposed, with the purpose of increasing interfacial adhesion of UHMWPE fiber. Inspired by mussel adhesion, polydopamine (PDA) was deposited onto the surface of UHMWPE fiber to form a thin layer with amino and hydroxyl groups. M‐SiO2 nanoparticles were then adhered to fiber surface via chemical reactions by a “two‐step” or “one‐step” technology. In the “two‐step” technique, the M‐SiO2 nanoparticles were adhered to the surface of PDA modified UHMWPE fiber via reactions between epoxy and amino groups. In the “one‐step” method, M‐SiO2 and dopamine were added into the UHMWPE/Tris solution at the same time. Surface morphology and thermal properties of various UHMWPE fibers were tested by SEM and TGA, respectively. Surface wettability of different UHMWPE fibers were evaluated by dynamic contact angle. The results proved that PDA and M‐SiO2 were successfully adhered to the surface of UHMWPE fibers. The mechanical property of modified UHMWPE/Epoxy composites was investigated, and 43.7 % improvement was obtained, compared with unmodified UHMWPE/Epoxy composite. Additionally, micro‐bond test revealed that the interfacial property (IFSS value) of modified UHMWPE fiber via the “one‐step” method was 6.08 MPa, significantly higher than that of unmodified UHMWPE fiber (2.47 MPa). [ABSTRACT FROM AUTHOR]

AbstractExcessive boron (B) levels in soil can lead to toxicity in plants, impacting their growth and productivity. Effective strategies to reduce B uptake are important for improving crop performance in contaminated soils. This experiment aimed to investigate the effects of chicken manure incineration ash (CMA) and triple superphosphate (TSP) on B uptake in barley plants grown in B-contaminated soil. Before the experiment, the chemical composition and molecular structure of CMA were analyzed using XRF, XRD and SEM. The soil was contaminated with 15 mg kg−1 of B, and both TSP and CMA were applied at rates of 40, 80, and 160 mg kg−1 of phosphorus (P). Neither P source had a significant impact on plant dry weight. However, increasing doses of applied TSP and CMA increased plant P concentration while significantly decreasing B concentration. Particularly with CMA applied at 160 mg kg−1 P dose, plant B concentration decreased to the lowest level of 194 mg kg−1. Increasing P doses led to a slight decrease in plant silicon (Si) concentration. The pH of soil samples taken after the experiment slightly increased with CMA treatments compared to TSP. The available P concentration in soils increased with increasing P doses. The available B concentration decreased with increasing P doses, especially reducing to the lowest level of 2.52 mg kg−1 in soils with a 40 mg kg−1 P, CMA. In conclusion, in addition to the effect of P, the molecular structure of P is also important in reducing B uptake in barley. [ABSTRACT FROM AUTHOR]

AbstractThe single source precursor tris(N,N,N’,N’-tetramethylethylenediamine)Al(III)Cl3 has been synthesized by the reaction of N,N,N’,N’-tetramethylethylenediamine (TMEDA) with AlCl3 in 3:1 molar ratio in ethanol. The precursor is stable for long periods of time and cleanly generated aluminum nitride upon pyrolysis. The pyrolysis process was optimized by varying parameters such as temperature, pressure, and the flow rate of gases (N2 and Ar). Thin films of AlN were prepared by spin coating the precursor onto Si(100) and quartz substrates followed by pyrolysis under optimized CVD conditions obtained from bulk pyrolysis. Pyrolyzed powders and films were characterized with a variety of techniques. X-ray diffraction (XRD) showed 8.5 nm grain size with a dominant 220 orientation. UV-Vis spectroscopy indicated a band gap for the AlN films of ∼5.7 eV, which is close to bulk AlN (6.1 eV). FESEM showed a smooth and homogeneous film surface and EDAX showed a 1.4:1 ratio of Al:N, respectively. [ABSTRACT FROM AUTHOR]

Developing biodegradable electrodes is a significant step toward environmental sustainability and cost reduction in battery technology. This paper presents a new approach that utilizes metal‐organic framework (MOF)‐encapsulated silicon nanoparticles (SiNPs) as the active anode material within a cellulose‐based electrode. The electrode is free‐standing, flexible, biodegradable, and significantly reduces the strain experienced by SiNPs during volume expansion, resulting in improved capacity and cycle life stability of SiNPs. The high porosity of the electrode creates efficient lithium (Li+) ion transport channels and enhances electrolyte absorption, thus promoting effective contact between the electrolyte and active material. The outcome is rapid electrode kinetics and a highly reversible discharge capacity of 1744.6 mAh g−1 at 0.5 A g−1 versus Li/Li+ over 1000 cycles. Further, full cell tests are conducted that demonstrate a stable cycle performance exceeding 3400 cycles, with an initial discharge capacity retention of 80.5% at 0.5 A g−1. By employing cellulose and avoiding toxic organic solvents and binders, the proposed approach is promising for a substantial reduction of the production costs of Li‐ion batteries. The scalability of the proposed method further enhances its practical viability, offering intriguing economic implications for the future of battery technology. [ABSTRACT FROM AUTHOR]

We report an ultra-shallow p-type doping of silicon resulting from the rapid thermal annealing of thin Al2O3 films deposited on intrinsic silicon with a native SiO2 layer, using a common atomic layer deposition process. Characterization revealed a two-stage decrease in sheet resistance, providing insights into the doping mechanism. [ABSTRACT FROM AUTHOR]

Silicon (Si) application may affect the plant response to nitrogen (N), possibly by changing the uptake, concentration, and partitioning of nutrients in plant tissues; however, this has not yet been proven in Arabica coffee plants. The effects of Si application methods [no Si, soil-applied soluble Si (168 mg Si L−1), and foliar-applied soluble Si (two application of 2 mg Si plant−1)] and N levels (0 and 80 mg N L−1) on biomass production and partitioning and uptake, partitioning, and stoichiometry of nutrients and Si in young Arabica coffee plants grown under greenhouse conditions were evaluated. Nitrogen fertilization increased the biomass production and uptake of all nutrients; however, reduced the concentrations of K, Ca, Mg, S, Mn, and Si in the leaves, Si in the stems, and K, Mg, and S in the roots of coffee plants as a dilution effect. In the presence of N, soil-applied Si increased the concentrations of Zn in the leaves and Ca and Si in the stems, the uptake of K, S, and Si, and the Si:N ratio. Foliar-applied Si increased the concentrations of N, P, K, and Zn in the leaves and Ca and Si in the stems, as well as the total uptake of K and Si and the Si:N ratio in coffee plants, being more evident in the N fertilization presence. This study unraveled that, especially when it was soil-applied, Si altered the nutrient uptake, allocation, and stoichiometric ratios with N, with a consequent increase in biomass production of young coffee plants fertilized with N. [ABSTRACT FROM AUTHOR]

The soil microbiome plays a pivotal role in the functioning and resilience of agricultural ecosystems, contributing to critical processes such as organic matter decomposition, nutrient cycling, and plant growth promotion. However, the soil microbiome is constantly challenged by various environmental stresses, including drought, heavy metal contamination, salinity, and climate change, which can significantly disrupt the delicate balance of the soil ecosystem. In this context, the application of silicon (Si) has emerged as a promising strategy to mitigate the adverse effects of these environmental stresses on the soil microbiome. This review paper synthesizes the current understanding of the impacts of environmental stresses on the soil microbiome and explores the potential of Si as a mitigating agent in enhancing the resilience of the soil microbial community. Silicon can enhance the resilience of the soil microbiome through several mechanisms, such as increasing soil pH, improving nutrient and water availability and uptake, altering root exudation patterns and plant physiology, and directly stimulating the abundance, diversity, and functional potential of key microbial groups. By enhancing the resilience of the soil microbiome, Si application can help maintain the critical ecosystem services provided by soil microorganisms, ultimately contributing to the sustainability and productivity of agricultural systems. The review also highlights future research aspects, including elucidating the precise mechanisms of Si-microbiome interactions, evaluating the long-term effects of Si on soil microbiome resilience, optimizing Si application strategies for specific crop-soil systems, integrating Si management with other sustainable soil practices, and assessing the impacts of Si on soil microbiome-mediated ecosystem services. [ABSTRACT FROM AUTHOR]

Hybrid metasurfaces incorporated by active materials hold great promise for state‐of‐the‐art terahertz functional devices. However, it is still a major challenge to achieve ultrafast, dynamic, and multifunctional effective control of THz waves via hybrid metasurfaces. Herein, a modulator consisting of split rings and cut‐wires is first demonstrated, with an amplitude of −35.6 dB at 0.524 THz. By embedding semiconductor silicon into specified locations to form a hybrid metasurface, the ultrastrong connectivity of the silicon bridges leads to rapid optical molecularization. Under photoexcitation, the frequency tuning range is 26.7%, the phase shifting reaches 357.5°, and the maximal modulation depth is 94.54%. Taking advantage of the rapid relaxation of photocarriers in the silicon bridges, the ultrafast frequency switching is within 1400 ps. More interestingly, by changing the positions of the silicon bridges, the frequency tuning range is further promoted to 60%, the phase shifting is 353.5°, the modulation depth of 100% is achieved, and the full recovery time is 1600 ps. Furthermore, the underlying mechanism of the ultrafast tuning process is elucidated. This work demonstrates the feasibility of all‐optical‐controlled hybrid metasurface to achieve multifunctional dynamic modulation of THz waves, which has tremendous potential for applications in optical switching, signal processing, and frequency conversion. [ABSTRACT FROM AUTHOR]

Nearly four decades have passed since IBM scientists pioneered atomic force microscopy (AFM) by merging the principles of a scanning tunneling microscope with the features of a stylus profilometer. Today, electrical AFM modes are an indispensable asset within the semiconductor and nanotechnology industries, enabling the characterization and manipulation of electrical properties at the nanoscale. However, electrical AFM measurements suffer from reproducibility issues caused, for example, by surface contaminations, Joule heating, and hard‐to‐minimize tip drift and tilt. Using as experimental system nanoscale Schottky diodes assembled on oxide‐free silicon crystals of precisely defined surface chemistry, it is revealed that voltage‐dependent adhesion forces lead to significant rotation of the AFM platinum tip. The electrostatics‐driven tip rotation causes a strain gradient on the silicon surface, which induces a flexoelectric reverse bias term. This directional flexoelectric internal‐bias term adds to the external (instrumental) bias, causing both an increased diode leakage as well as a shift of the diode knee voltage to larger forward biases. These findings will aid the design and characterization of silicon‐based devices, especially those that are deliberately operated under large strain or shear, such as in emerging energy harvesting technologies including Schottky‐based triboelectric nanogenerators (TENGs). [ABSTRACT FROM AUTHOR]

Strain is commonly used in metal–oxide–semiconductor technologies to boost on‐state performance. This booster has been in production for at least a decade. Despite this, a systematic study of the impact of strain on off‐state leakage current has been lacking. Herein, experimental data and ab initio calculations are used to refine existing models to account for the impact of strain on band‐to‐band tunneling and trap‐assisted tunneling in silicon. It is observed that the strain may dramatically increase the leakage current, depending on the type of tunneling involved. For band‐to‐band and trap‐assisted tunneling, low uniaxial strains of 0.1% (or 180 MPa) can increase the leakage current by 60% and 10% compared to the unstrained case, respectively. Using models, it is predicted that compressive strain on the order of 1% (or 2 GPa) can increase the leakage current by 150 times. Conversely, tensile strain may diminish or at most double the leakage current in all observed cases. Though detrimental in conventional inversion‐mode metal‐oxide‐semiconductor field‐effect‐transistor, these processes may be used to boost the performance of tunnel field‐effect transistors, where on‐state current is defined by band‐to‐band tunneling. [ABSTRACT FROM AUTHOR]

A chemo- and regioselective hydroarylation of vinylsilanes with (hetero)aryl iodides under Ni–H catalysis is reported. This mild and straightforward protocol furnishes the anti-Markovnikov products in good yields as single regioisomers. This study demonstrates excellent control over the chemoselectivity and complements existing methods for the construction of homobenzylic silanes. [ABSTRACT FROM AUTHOR]

Silicon (Si) is a versatile nutrient that plays an instrumental role in mitigating biotic and abiotic stresses besides improving growth and yield of graminaceous crops. We hypothesized that application Si would significantly improve productivity and resilience of wheat. Hence, the objectives were a) to assess the impact of Si application on wheat growth, productivity, nutrient uptake, water use efficiency, and b) to determine the potentiality of Si in mitigating lodging and aphid density. Therefore, we conducted a field experiment with five levels of Si (0, 2, 4, 6, and 8 g Si liter−1) at three growth stages (crown root initiation, tillering, and jointing stage) using a factorial randomized block design replicated three times. The results showed that increasing Si doses positively influenced plant height, dry matter accumulation (DMA), leaf area index (LAI), yield, and nutrient uptake. The highest grain and straw yield were observed with 8 g Si liter−1, followed by 6 g Si liter−1, while the control had the lowest yields. With 8 g Si liter−1, grain yield, straw yield, and Si uptake increased by 10.5%, 13.5%, and 26.3%, respectively, compared to the control. Additionally, Si application at 8 g Si liter−1 significantly reduced the density of S. avenae (aphids) by 81.4% and lodging by 75.1% compared to the control. Overall, the study demonstrated that increasing Si doses enhanced various growth and yield parameters, with 8 g Si liter−1 and 6 g Si liter−1 showing superior results. Among the growth stages, foliar application of Si during the tillering stage exhibited better performance in terms of growth, yield, and nutrient uptake in wheat. Therefore, the study concludes that Si fertilization at a rate of 8 g Si liter−1 during the tillering stage can effectively improve growth, productivity, and nutrient uptake in wheat in the southern region of Rajasthan. [ABSTRACT FROM AUTHOR]

Silicon (Si) anode is of considerable interest in Li‐ion batteries due to its high theoretical capacity (4200 mAh g−1), abundant reserves in the earth, and environmentally friendly nature. Although Si anode has significant advantages, the electrode is prone to cracks due to large volume changes in its structure during discharge cycles in Li‐ion batteries. Rapid capacity degradation occurs as a result of deterioration of the structural integrity of the electrode. Although binders are known to contribute to improving the electrochemical performance of anode materials, polyvinylidene fluoride (PVdF) used in commercial Li‐ion batteries cannot maintain the mechanical stability of the Si anode during cycles due to weak Van der Waals interactions, which also dissolves in the flammable, explosive and volatile solvent N‐Methyl‐2‐pyrrolidone (NMP). In this study, low cost, sustainable and environmentally green psyllium gum (PG) was extracted from psyllium husk and tested for the first time as a water‐soluble binder for Si anode. According to galvanostatic charge/discharge tests, the Si‐PG anode exhibits a capacity of 1415 mAh g−1 after 100 cycles at a voltage range of 0.01–1.5 V and current density of C/2, which is almost 3 times higher than the Si‐PVdF anode (494 mAh g−1). [ABSTRACT FROM AUTHOR]

Farmed aquaculture species play an important role in regulating nutrient cycles in farming systems. Compared with nitrogen and phosphorus, the role of farmed species in the silicon (Si) cycle remains poorly understood. To help reduce this uncertainty, we clarified the sources and sinks of silicate and quantified the Si pools in an aquaculture system in Sanggou Bay (SGB). The results showed that dissolved inorganic nutrient levels were significantly lower during the dry season than during the wet. Dissolved silicate (DSi) is a potential limiting factor for phytoplankton growth during spring, and phosphorus limitation occurs during summer. The budget results indicated that large amounts of nitrogen, phosphate (DIP), and DSi were buried in the sediment or transformed into other forms during both the wet and dry seasons. The nitrogen and DIP cycles were strongly influenced by bivalve excretion and farmed species harvesting; however, these processes had little impact on the Si cycle. Si availability depends on both external inputs and internal recycling. DSi was primarily supplied from the Yellow Sea, with a minor contribution from the river due to river discharge during spring. However, during summer, riverine inflow (accounting for 83% of the total influx) was the major DSi source followed by benthic flux (12%). Biogenic silica (BSi) burial efficiency in the sediment was estimated to be 78% during spring and 23% during summer. The BSi preservation efficiency in bivalves during spring was high (53%), leading to a higher Si retention than in river discharge. Bivalves biodeposition plays an important role in the Si burial process. We suggest that this high retention is essentially controlled by the biodeposition mechanism, which is directly controlled by the exotic suspension feeders. Bivalves have the potential to alter Si retention in the bay by producing large amounts of biodeposits and accelerating the silica cycle, which may lead to more carbon dioxide being absorbed by diatoms. [ABSTRACT FROM AUTHOR]

Silicon, carbon and oxygen hybrid nanomaterials (i.e., SiCOHNs) have recently drawn extensive attention as versatile photoluminescence (PL) nanosystems. The collective advantages of silicon‐ and carbon‐based nanostructures have resulted in SiCOHNs with tunable and photostable PL properties, abundant possibilities for surface modification, and low biotoxicity. Although SiCOHNs have shown great potential in diverse applications, such as bioimaging, biosensing, drug delivery and information encryption, discovering novel SiCOHNs with explicit nanostructures and elucidating the fundamental mechanisms of their PL properties for bioapplications are highly desirable. In this review, on the preparation of SiCOHNs on the basis of the synthesis conditions and precursors are first focused. Next, the manipulation of the emission wavelength, quantum yield and RTP of SiCOHNs is discussed. On the basis of previous reports and the recent experimental/theoretical results, the primary structure of SiCOHNs is clarified and deduced their possible PL mechanism. SiCOHNs possess bacterial uptake efficiency and/or anticancer capacity, promoting various biomedical applications and proof‐of‐concept applications in anti‐counterfeiting. Finally, current challenges and future trends are summarized as a roadmap for the development of SiCOHNs‐based optical applications. [ABSTRACT FROM AUTHOR]

In this paper, the dissolution behavior of crystal-originated particle (COP) in 300 mm Czochralski silicon under argon annealing was investigated. The latex sphere equivalent size distributions of defects along the depth direction in silicon wafers annealed under different conditions were quantified utilizing chemical–mechanical polishing and localized light scattering inspection. The interstitial oxygen concentration profiles were quantified by secondary ion mass spectrometry, and the distributions of oxygen precipitation within annealed wafers were obtained based on peak analysis. Furthermore, the classical theoretical model was employed to elucidate the depth-dependent dissolution of COP. Based on the initial COP sizes and oxygen concentrations, the relationship between COP sizes and depth after annealing was calculated. The depth distributions of defects obtained by combining the dissolution of COP from calculation with the changes of oxygen precipitation were found to be highly consistent with the measurement results. These findings could enhance the understanding of the mechanism of COP dissolution, which contributes to the production of defect-free silicon wafers for nanometre-scale integrated circuits. [ABSTRACT FROM AUTHOR]

Femtosecond-laser-fabricated black silicon has been widely used in the fields of solar cells, photodetectors, semiconductor devices, optical coatings, and quantum computing. However, the responsive spectral range limits its application in the near- to mid-infrared wavelengths. To further increase the optical responsivity in longer wavelengths, in this work, silicon (Si) was co-hyperdoped with nitrogen (N) and selenium (Se) through the deposition of Se films on Si followed by femtosecond (fs)-laser irradiation in an atmosphere of NF3. The optical and crystalline properties of the Si:N/Se were found to be influenced by the precursor Se film and laser fluence. The resulting photodetector, a product of this innovative approach, exhibited an impressive responsivity of 24.8 A/W at 840 nm and 19.8 A/W at 1060 nm, surpassing photodetectors made from Si:N, Si:S, and Si:S/Se (the latter two fabricated in SF6). These findings underscore the co-hyperdoping method's potential in significantly improving optoelectronic device performance. [ABSTRACT FROM AUTHOR]

A multi‐technique analysis was used to investigate how the orientation of single‐crystal Si wafer surfaces affects the size, shape and orientation of NiSi2 nanocrystals grown within the wafers through the thermal diffusion of Ni atoms from a nickel‐doped thin film deposited on the surface. Nickel‐doped thin films were prepared on silicon wafers with three distinct crystallographic orientations, [001], [110] and [111]. Three sets of samples were then annealed at 500, 600 and 700°C for 2 h. Regardless of crystallographic orientation or annealing temperature, NiSi2 nanoplates with a nearly hexagonal shape grew close to the external surface of the wafers, aligning their larger surfaces parallel to one of the planes of the Si{111} crystallographic form. The crystallographic orientation and annealing temperature in the 500–700°C range did not significantly affect the final values of the average diameter and thickness of the nanoplates. However, significant differences were noted in the number of nanoplates formed in Si wafers with different crystallographic orientations. The results indicate that these observed differences are correlated with the number of pre‐existing defects in the wafers that influence the heterogeneous nucleation process. In addition, the average size and size dispersion were determined for pores at the surface of the Si wafers formed due to the etching process used for native oxide removal. [ABSTRACT FROM AUTHOR]

Silicon significantly affects the microstructure and properties of wear-resistant alloys. To investigate the effect of silicon content on the microstructure and properties of high-vanadium wear-resistant alloys (HVWA), three alloys with different silicon content (HVWA-0.66Si, HVWA-2.14Si and HVWA-5.17Si) were formulated and synthesized. And the solidification structure and wear behavior of HVWAs were researched. The increased content of silicon enhances the precipitation temperature of VC and therefore promotes the formation of more pellet/agglomerate primary VC in solidification and decreases the content of strip eutectic VC. The as-cast structure of HVWAs comprises of pearlite, with numerous submicron carbides dispersed on the pearlite matrix. The increased content of silicon increases the lamellar spacing of pearlite and the particle size of submicron carbides. The lamellar spacing of pearlite in HVWA-0.66Si, HVWA-2.14Si and HVWA-5.17Si measures 50–300 nm, 200–600 nm and 300–1800 nm, correspondingly, while the size of the submicron carbides is 0.3–0.9 μm, 0.5–1.3 μm and 0.3–1.9 μm, accordingly. The impact toughness of the alloy reduces as the silicon content increases. The HVWA-5.17Si matrix has a hardness of 49.3 HRC and boasts exceptional wear resistance. Taking HVWA-0.66Si as a reference, the relative wear resistance ε of HVWA-5.17Si has the highest wear resistance, with ε reaching 1.75. The strong wear resistance of HVWA-5.17Si stems mainly from the solid solution of silicon in the matrix that heightens its hardness. This feature works in tandem with the high-hardness primary VC and an abundance of finely formed secondary vanadium carbides that precipitate in the as-cast alloy. [ABSTRACT FROM AUTHOR]

The near-eutectic aluminum–nickel alloys are promising to be used for thermal management purpose because of their excellent thermal conductivity. However, owing to the solid solubility of nickel in aluminum lattice is small, the mechanical properties of these alloys can barely be promoted via the solid solution strengthening effect. The present study investigates the trace addition of silicon on the microstructure, rheology property, mechanical performance and thermal conductivity of the Al–5Ni alloy. Results show that the α-Al grains in the Al–5Ni alloy with trace silicon are significantly refined, and the fibrous Al3Ni phase is notably modified. It leads to a remarkable improvement of its mechanical properties. However, the mechanical properties and thermal conductivity are prominently decreased when the dosage of silicon excesses 0.3 wt%. The molten Al–5Ni alloy with relatively high silicon content possesses wider temperature range for flowing, indicating a sound fluidity of the melts, which is related to the solidification routes of the samples. This work provides a reference for the design of cast aluminum alloys with high strength and excellent thermal conductivity. [ABSTRACT FROM AUTHOR]

Key message: Promoters of moso bamboo silicon transporter genes PeLsi1-1 and PeLsi1-2 contain elements in response to hormone, silicon, and abiotic stresses, and can drive the expression of PeLsi1-1 and PeLsi1-2 in transgene Arabidopsis. Low silicon 1 (Lsi1) transporters from different species have been shown to play an important role in influxing silicon from soil. In previous study, we cloned PeLsi1-1 and PeLsi1-2 from Phyllostachys edulis and verified that PeLsi1-1 and PeLsi1-2 have silicon uptake ability. Furthermore, in this study, the promoters of PeLsi1-1(1910 bp) and PeLsi1-2(1922 bp) were cloned. Deletion analysis identified the key regions of the PeLsi1-1 and PeLsi1-2 promoters in response to hormone, silicon, and abiotic stresses. RT-qPCR analysis indicated that PeLsi1-1 and PeLsi1-2 were regulated by hormones, salt stress and osmotic stress. In addition, we found that the driving activity of the PeLsi1-1 and PeLsi1-2 promoters was regulated by 2 mM K2SiO3 and PeLsi1-1-P3 ~ P4 and PeLsi1-2-P4 ~ 5 were the regions regulated by silicon. Overexpression of PeLsi1-1 or PeLsi1-2 driven by 35S promoter in Arabidopsis resulted in a threefold increase of Si accumulation, whereas transgenic plants showed deleterious symptoms and dwarf seedlings and shorter roots under 2 mM Si treatment. When the 35S promoter was replaced by PeLsi1-1 or PeLsi1-2 promoter, a similar Si absorption was achieved and the transgene plants grew normally. This study, therefore, demonstrates that the promoters of PeLsi1-1 and PeLsi1-2 are indeed effective in driving the expression of moso bamboo Lsi1 genes and leading to silicon uptake. [ABSTRACT FROM AUTHOR]

The synthesis of silanes starting from multifunctionalized precursors often suffers from low chemoselectivity due to the similar kinetic reaction profiles, leading to the formation of difficult to separate side products. The opposite approach, which is an access based on unreactive tetraalkylsilanes as starting materials, is far less developed. Making use of the silylium-ion-initiated chemoselective halodealkylation of tetraalkylsilanes recently developed by our laboratory, an extension of this protocol, namely the direct synthesis of dihalosilanes from tetraalkylsilanes, is reported. Following a sequence of halodehydrogenation and halodealkylation, trialkylhydrosilanes can also be converted into dihalosilanes. Commercially available 1,2-dihaloethane acts as the halogen source and is involved in the generation of the catalytically active arenium ion by an SE Ar substitution of the benzene solvent. The formation of an uncommon halogen-substituted silylium ion as an intermediate is assumed, likely accounting for the need of an elevated reaction temperature. [ABSTRACT FROM AUTHOR]