Silicon Nano Research Articles

Synthesis of Well-Ordered Functionalized Silicon Microwires Using Displacement Talbot Lithography for Photocatalysis.

Metal-assisted chemical etching (MACE) is a cheap and scalable method that is commonly used to obtain silicon nano- or microwires but lacks spatial control. Herein, we present a synthesis method for producing vertical and highly periodic silicon microwires, using displacement Talbot lithography before wet etching with MACE. The functionalized periodic silicon microwires show 65% higher PEC performance and 2.3 mA/cm2 higher net photocurrent at 0 V compared to functionalized, randomly distributed microwires obtained by conventional MACE at the same potentials.

The effectiveness of local action of nano oxides on wound infection

The treatment of wound-related combat injuries and antibiotic resistance require the search for new approaches to reduce the risk of infectious complications, this will increase the effectiveness of therapy and even save lives. The aim of our study was to establish the mechanism of action and effectiveness of nano oxides applied to wound infection. The antimicrobial activity of different concentrations of solutions of zinc (nZnO), magnesium (nMgO) and silicon (nSiO2) nano oxides was studied by agar diffusion against clinical antibiotic-sensitive strains of opportunistic Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), isolated from patients with purulent-septic diseases. It was found that nZnO exhibits extremely high antibacterial activity against S. aureus, E. сoli. The ultra-low content of nZnO (1.56 mg/ml) completely destroys S. aureus, unlike nMgO, the effective concentration of which exceeds the minimum by 16 times. It is known that nZnO has the highest antimicrobial properties against S. aureus and E. coli, this effectiveness is achieved due to the features of the structure and the possibility of the formation of oxygen and a number of other radicals. These qualities of nZnO make it possible to integrate it into dressings for wound treatment.

Progress in the application of silicon-based anode nanotechnology in lithium batteries

With the development of technology, graphite materials in traditional lithium batteries can no longer meet people’s needs due to their relatively low specific capacity, limited charging and discharging rates, and poor safety. Silicon has a very high theoretical specific capacity, far exceeding traditional graphite negative electrode materials, making silicon nanoparticles an ideal choice for improving the energy density of lithium-ion batteries. In this paper, we first introduce the silicon nanoparticle anode and its preparation methods: mechanical ball milling, and thermal cracking, and introduce the application of binders in it. Secondly, the silicon nanowire anode and the chemical deposition method for its preparation are introduced, and the high-performance silicon nanowire lithium battery of Amprius is introduced. Thirdly, the preparation of silicon thin film anode and two types of composite film was introduced. Finally, the three types of silicon nano anodes are summarized and prospected. This paper has reference significance for the future research of silicon-based lithium-ion batteries.

A Scalable Furnace Technique to Grow Silicon Nanoparticles for High-Performance Li-Ion Battery Anodes

Lithium-ion battery (LIB) technology is one of the key technologies to lower the emission from fossil fuel while maintaining stable supply of energy to the society. One way to increase the capacity of LIBs is to add silicon to the graphite anode, since silicon can store much more lithium ions than graphite. Silicon does however expand and contract during lithiation and delithiation, leading to cracks which deteriorates the performance of the LIB anode. Mechanical cracking can be avoided by using sufficiently small silicon nanoparticles. Several high-performance schemes utilizing silicon nano materials such as nanoparticles, nanotubes, nanorods etc. have been demonstrated but industrial-scale implementation of these solutions still poses a challenge. The Siemens process is one of the most commonly used methods to create silicon nanoparticles and uses chemical vapor deposition (CVD) processes involving silane or silane derivatives as precursors. Due to the flammable and toxic nature of silane, the CVD process requires special handling care and expensive instrumentation. In this work, a novel scalable furnace technique to create silicon nanoparticles attached to graphene flakes LIB anode applications is presented. With this technique, we can avoid the silane precursor. In addition, the instrumentation requirements of the furnace technique are quite simple and inexpensive and the technology is compatible with already established industrial-scale electrode manufacturing techniques.In the work presented here we demonstrate how silicon nanoparticles are grown from micro sized silicon powder onto graphene flakes using simple thermal treatment. Thermal gravitometry, mass spectrometry and differential scanning calorimetry was used to show how silicon powder and a binder can be converted to silicon nanoparticles by simple pyrolysis. The silicon nanoparticles are grown on top of graphene flakes to create a LIB anode. The anode, when tested in a half cell assembly shows a capacity that is considerably higher than standard graphene/graphite electrodes.

Emulation of neuro-mimetic dynamics via GaSb/Si heterojunction V-DGTFET leaky-integrate-fire silicon neuron

A leaky integrate and fire (LIF) neuron property is emulated using vertically developed double gate GaSb/Si tunnel field effect transistor (V-DGTFET). The suggested device can precisely replicate the neuronal dynamics after considering and proper validating the numerical simulations. Silvaco-TCAD tool is exploited for emulation of neuronal attributes and found in good agreement with earlier published research data. The article reports the membrane threshold voltage of 0.47 V which is 3.2x, 2.13x, 2.13x, 1.28x times less as compared to silicon nanowire, MOSFET, phase change device and Bulk FinFET neuron. The energy required for mimicking the neurons is computed as 0.748 aJ which is 1.2 × 109, 4 × 107, 4.68 × 107, 1.34 × 107, 7.59 × 106, 8.42 × 103, 4.30 × 103 3.34 × 105, 2.41 × 105, 1.52 × 106, 26.7,2, 3.88 × 103 times less compared to CMOS, phase change device, SOI CMOS, PCMO RRAM, SiNPN, Bulk FinFET, BTBT based PDSOI MOS, FBFET, LBIMOS, DGJLFET, Si NIPIN, DL-TFET, silicon nano wire respectively. The biasing at second gate is used to induce potential well at channel region to accumulate hole carriers produced due to impact ionization. The threshold current is achieved at 0.20 V drain voltage which is 15x, 14x, 10x, and 1.5x less as compared to FinFET, PD-SOI MOSFET, LBIMOS, and DLTFET respectively. Furthermore, calculated spiking frequency of V-DGTFET LIF neuron is 534 GHz. Thus, remarkable enhancement in frequency of operation and an ultra-low energy per spike makes this neuron device a potential solution for implementing the neuro-mimetic behaviour at large scale.

Investigation of perfect narrow-band absorber in silicon nano hole array

In this paper, we proposed a triple layer structure consisting of the bottom silver layer, thin silicon oxide space layer, and ultrathin semiconductor silicon film with nano hole array achieving three absorption peaks with narrow band. The absorption spectrum can be easily controlled by adjusting the structural parameters including the radius and period of the nano hole array, and the maximal absorption can reach 99.0% and the narrowest full width of half maximum can reach about 6.5 nm in theory. We also clarified the physical mechanism of the proposed structure in details by finite-difference time-domain simulation, in which the three narrow band perfect adsorption peaks can be attributed to electric dipole resonance, magnetic dipole resonance and plasmonic resonance respectively. At the same time, we used a low-cost nanosphere lithography method to fabricate the proposed nano hole array in large area. In experiment, the absorption peak of the proposed triple layer structure can reach up to 98.3% and the narrowest full width of half maximum can reach up to about 10.1 nm. The highest quality factor Q can reach up to 98.4. This work can open a new avenue for high-quality factor narrow band perfect absorption using ultrathin semiconductor film and benefit for many fields such as infrared sensors, plasmonic filters, and hyperspectral imaging.

Ultrathin Crystalline Silicon Nano and Micro Membranes with High Areal Density for Low-Cost Flexible Electronics.

Ultrathin crystalline silicon is widely used as an active material for high-performance, flexible, and stretchable electronics, from simple passive and active components to complex integrated circuits, due to its excellent electrical and mechanical properties. However, in contrast to conventional silicon wafer-based devices, ultrathin crystalline silicon-based electronics require an expensive and rather complicated fabrication process. Although silicon-on-insulator (SOI) wafers are commonly used to obtain a single layer of crystalline silicon, they are costly and difficult to process. Therefore, as an alternative to SOI wafers-based thin layers, here, a simple transfer method is proposed for printing ultrathin multiple crystalline silicon sheets with thicknesses between 300nm to 13µm and high areal density (>90%) from a single mother wafer. Theoretically, the silicon nano/micro membrane can be generated until the mother wafer is completely consumed. In addition, the electronic applications of silicon membranes are successfully demonstrated through the fabrication of a flexible solar cell and flexible NMOS transistor arrays.

Encapsulation of Silicon Nano Powders via Electrospinning as Lithium Ion Battery Anode Materials.

Silicon-containing polyester from tetramethoxysilane, ethylene glycol, and o-Phthalic anhydride were used as encapsulating materials for silicon nano powders (SiNP) via electrospinning, with Polyacrylonitrile (PAN) as spinning additives. In the correct quantities, SiNP could be well encapsulated in nano fibers (200-400 nm) using scanning electron microscopy (SEM). The encapsulating materials were then carbonized to a Si-O-C material at 755 °C (Si@C-SiNF-5 and Si@C-SiNF-10, with different SiNP content). Fiber structure and SiNP crystalline structure were reserved even after high-temperature treatment, as SEM and X-ray diffraction (XRD) verified. When used as lithium ion battery (LIB) anode materials, the cycling stability of SiNPs increased after encapsulation. The capacity of SiNPs decreased to ~10 mAh/g within 30 cycles, while those from Si@C-SiNF-5 and Si@C-SiNF-10 remained over 500 mAh/g at the 30th cycle. We also found that adequate SiNP content is necessary for good encapsulation and better cycling stability. In the anode from Si@C-SiNF-10 in which SiNPs were not well encapsulated, fibers were broken and pulverized as SEM confirmed; thus, its cycling stability is poorer than that from Si@C-SiNF-5.

Fabrication of a Polymer Nano Nozzle for Electrohydrodynamic Small-Molecule Solvent Inkjet Printing

Electrohydrodynamic jet (E-jet) printing promises to become a highly efficient and cost-effective high-resolution additive nanomanufacturing technology. However, nanoscale printing of small-molecule solvent inks requires the fabrication of nano nozzles that will accommodate the considerable spreading of the printed droplets. This study documents our steps in developing a fabrication process for nanoscale printing nozzles. First, a silicon nano nozzle mold was fabricated by side-etch lift-off, ultraviolet lithography, and deep reactive ion etching. Then, the nanoscale polymer nozzle was produced by double-casting polydimethylsiloxane and a bonding process. In the application of a polymer nano nozzle for E-jet printing of ethanolic solutions of 1-hexadecanethiol, droplets with a diameter as small as 160 nm were obtained. These results indicate that a polymer nano nozzle can be well adapted to E-jet printing with a fine resolution.

Investigation of Xanthan Gum and Carboxymethyl Cellulose Binders for the Silicon Anode of Lithium-Ion Batteries

The binder is known to play an important role in the cycle stability of silicon-based anodes for lithium-ion batteries. Nature-derived biopolymers such as sodium carboxymethyl cellulose (NaCMC) and xanthan gum (XG) are a promising class of binders that offer several advantages over traditional polyvinylidene fluoride (PVDF). Advantages include better contact between silicon particles and the ability to process the electrodes using water as a solvent. While many studies have explored the fundamental properties of these biopolymer binders and their interaction with silicon, there has been little research on the use of these binders under practical loadings (such as ∼2 mg Si cm−2 and <10 wt% binder). Herein, we compare the electrochemical performance of both NaCMC and XG-based silicon electrodes with a low binder content. Si-binder interactions and their role in electrode performance are revealed with XPS, SEM, and EDX. In addition, we report the results of both a high-silicon (80 wt% Si) and a practical low-silicon (20 wt% Si) composite electrode while using silicon nano powder prepared by industrial-scale synthesis. It is found that NaCMC consistently outperforms XG as a binder, which is attributable to superior cohesion within the electrode.

New application of a periodic mesoporous nanocrystal silicon-silica composite for hyperlipidemia.

The integration of the properties of silicon nano crystallinity with silica mesoporosity provides a wealth of new opportunities for emerging biomedicine. Cholesterol (CHO) and triglyceride (TG) levels have always been a challenge for cardiologists in the treatment of patients with chronic coronary artery disease (CAD). For patients with hyperlipidemia, statins and other lipid-lowering drugs are currently recommended. It should be noted, however, that significant side effects have been reported in the treatments, including liver damage, muscle pain, etc. We here found that our previously produced periodic mesoporous nanocrystalline silicon-silica, meso-ncSi/SiO2 (PMS), a nanocomposite material, has the properties of lowering CHO and TG, and is associated with better safety and biocompatibility compared to existing lipid-lowering drugs. After being incubated with PMS for 2 hours, CHO and TG levels in blood were significantly lower than before. In addition, CHO and TG adsorbed on with PMS could also be extracted and released, contributing to the recovery and recycling of PMS.

Study of Wear, Stress and Vibration Characteristics of Silicon Carbide Tool Inserts and Nano Multi-Layered Titanium Nitride-Coated Cutting Tool Inserts in Turning of SS304 Steels.

Cutting tool characterization plays a crucial role in understanding the behavior of machining operations. The selection of a suitable cutting material, the operating conditions for the work piece, is necessary to yield good cutting-tool life. Several pieces of research have been carried out in cutting-tool characteristics for turning operation. Only a few pieces of research have focused on correlating the vibrations and stress with wear characteristics. This research article deals with stress induced in silicon carbide tool inserts and coated tool inserts while machining SS304 steel. Since this material is much less resistant to corrosion and oxidation it is widely used in engineering applications such as cryogenics, the food industry and liquid contact surfaces. Moreover, these materials have much lower magnetic permeability so they are used as nonmagnetic engineering components which are very hard. This article focuses on the machining of SS304 by carbide tool inserts and then, the cutting forces were observed with a tool dynamometer. Using observed cutting forces, the induced stress in the lathe tool insert was determined by FEA investigation. This research also formulates an idea to predict the tool wear due to vibration. Apparently, the worn-out tool vibrates more than new tools. Using the results, the relation between stress, strain and feed rate, depth of cut and speed was found and mathematically modeled using MINI TAB. It was observed that carbide tool inserts with coating withstand better than uncoated tools while machining SS304. The results were anticipated and correlation between the machining parameters furnished the prediction of tool life and obtaining the best machining outcomes by using coated tool inserts.

The edge-coupler of fiber-to-chip with ultra-low coupling loss based on double-layer silicon waveguides

The edge-coupler of fiber-to-chip with ultra-low coupling loss is demonstrated on SOI platform. The edge-coupler is consisted of the cantilevered SiO2 waveguide, the amorphous silicon (α-Si) nano taper and the crystal silicon (c-Si) nano tapers. The thin α-Si layer is deposited on the c-Si layer to improve the pattern matching with fiber. The optical input signal from the optical fiber is launched into the suspended SiO2 waveguide, then coupled into the α-Si nano taper at the center of the SiO2 waveguide, and finally coupled into the c-Si nano taper. We characterized the cantilevered edge-coupler using cleaved single-mode optical fiber with a mode field diameter of 10.5 μm. The measured coupling loss is as low as -1.7 dB per facet for TE mode without index matching liquid at 1550 nm. The 1 dB bandwidth is more than 100 nm with 1 dB alignment tolerances of ±2.0 μm in both horizontal and vertical directions. Besides, potential hybrid optical integration could also be allowed with this results in the future.

Highly efficient spin-polarized beam splitter based on silicon Pancharatnam–Berry metasurface

The spin-polarized conversion and splitting of beam are highly important for photonic researches and applications. Although the photonic spin Hall effect (PSHE) realized by the Pancharatnam–Berry (PB) metasurface has shown unprecedented capabilities to control spin-polarized light, spin-polarized beam splitting metadevices suffer from the limitations of low-efficiency. Here, we present a highly efficient spin-polarized beam splitter (SPBS) based on PB metasurface comprising silicon nano elliptical cylinder (Si-NEC) arrays. Because of the electromagnetic multipole resonance inside the designed Si-NECs, the PB metasurface can achieve high transmittance and enhanced PSHE. Therefore, the SPBS based on the PB metasurface can achieve a high spin conversion efficiency of nearly 100%, while ensuring a transmittance of 87% at 622 nm wavelength. It can also maintain a good working effect within the bandwidth of 600–660 nm. Furthermore, by introducing spatial shift between the two reverse Si-NEC arrays, the SPBS can also be used to realize 45° polarization rotation of an incident linearly polarized light, avoiding the input polarization angle dependence. Our design may have potential applications in high-performance and broadband spin-photonic devices.

Structure and properties of silicon nano- and microparticles obtained by electric-spark dispersion method

Silicon nano- and microparticles obtained using electric-spark dispersion of silicon electrodes and granules in 40 wt% solution of methyl alcohol in water were investigated by ultrasoft X-ray emission spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning and transmission electron microscopies. In addition, the SiLα spectra of obtained silicon particles were modeled by superimposing the spectra of pure silicon and silicon oxide taken in certain weight ratios. It was found that the surfaces of Si nano- and microparticles obtained in 40 wt% solution of methyl alcohol in water are covered with silicon oxide and chemisorbents, while the core consists of crystalline silicon with a cubic face-centered lattice. The silicon nano- and microparticles show potential as an anode material to replace commonly used graphite electrodes. The charge capacity of the electrode based on mixture of Si nano- and microparticles with graphite powder was about 1272 mAh/g after ten cycles.

Improved bidirectional networks for nanostructure color design

Localized optical resonances in silicon nanostructures have been increasingly used in color printing. By changing the geometric parameters of the silicon nanostructures to obtain different structural colors, it is possible to get a larger coverage range than the sRGB color gamut in the CIE color space, and achieve ultra-high-resolution color printing. However, the design of specific colors involves iterative optimization of geometric parameters, which is computationally expensive. Thus, it is very challenging to obtain millions of different colors in the color space. In this paper, we trained a feature-crossed neural network with attention mechanism to predict the structural color produced by random silicon nano truncated cones with high accuracy. On the problem of inverse design, we improve the loss function of the tandem network, which solves the non-uniqueness problem in the inverse design process and avoids the tandem net from falling into the wrong solution space. Our model can accurately predict millions of different color points in the CIE color gamut. In addition, the proposed methods can be easily extended to solve the optimization design problems in the field of nanophotonics.

Electric Arc Synthesis of Silicon Nanostructures

The paper proposes a method for the synthesis of silicon carbide of microscopic sizes and silicon Nano formations in the form of nanotubes and nanofilaments in an argon arc. Graphite electrodes with silicon inclusions were used as arc discharge electrodes. The electrodes were placed in a plasma reactor in an upright position at an argon pressure of 485 Torr. During the discharge, carbon and silicon atoms evaporated from the anode surface. As a result of the experiment, deposits of silicon carbide were formed on the surface of the graphite cathode, and carbon-silicon nanostructures were formed on the surface of the anode. The synthesized samples were analyzed on an electron microscope.

Spatially varying chemical phase formation on silicon nano ripple by low energy mixed ions bombardment

We report mixed (CO+ and N2 +) ion beam induced spatially varying chemical phases formation on Si (100) surface in nanometer length scale. Simultaneous bombardment of carbon, oxygen and nitrogen like three reactive ions leads to well-defined ripple development and spatially varying periodic chemical phases formation. Post bombardment chemical changes of Si surface are investigated by x-ray photoelectron spectroscopy, and spatially resolved periodic variation of chemical phases are confirmed by electron energy loss spectroscopy. The thickness of ion modified amorphous layer, estimated by Monte Carlo simulation (SRIM), is in excellent agreement with the cross-sectional transmission electron microscopy measurements. The formation of such periodic nanoscale ripple having multiple chemical phases at different parts is explained in terms of chemical instability, local ion flux variation and difference in sputtering yield. Potential applications of such newly developed nano material are also addressed.

All-electrical antibiotic susceptibility testing within 30 min using silicon nano transistors

Rapid and reliable antibiotic susceptibility testing (AST) platform is highly desired to select the right antibiotics to treat infectious disease at early stage. Here, we demonstrate rapid ASTs using nanoscale silicon ion-selective field-effect transistor sensors. Our sensors profile bacterial metabolic kinetics by monitoring the metabolism induced acidification in the growth media with the absence and the presence of different antibiotics. Rapid AST results could be determined from the metabolic profiles with a total assay time less than 30 min for different bacterial strains. In addition, the sensors could also distinguish the bactericidal mechanisms for antibiotics with different modes of actions. Furthermore, the initial bacterial concentration in an unknown sample, a key parameter to determine its clinic relevance, could be estimated based on the metabolic profiles. Our demonstrated AST method is all-electrical, label-free and silicon technology compatible, and holds great promise for the development of a high-throughput and low-cost point-of-care device.

بررسی پاسخ گیاه ارزن (Panicum miliaceum) به کاربرد اسید هیومیک، سیلیسیم و میکوریزا در شرایط تنش شور سدیمی آب آبیاری

IntroductionSalinity and sodicity stresses are the major problems in the production of crops under arid and semi-arid regions. Sustainable management by using water and soil resources, under conditions of salinity and sodicity, is considered as a management strategies, also application of mycorrhizal fungi along/or organic matter such as humic acid addition are the major causes in reclamation of the environment and also increases the stability of agro-systems by reducing the use of chemical fertilizers. Among other ways to overcome the negative effects of salinity on the growth and yield of the plant, application of ordinary silicon and silicon nanoparticles have prior importance. This research was conducted to evaluate the effect of humic acid, mycorrhiza and silicon (ordinary and nano) on yield and nutrient content of millet under saline-sodic irrigation water. Materials and methodsA field experiment was conducted as split plot factorial in a randomized complete block design with three replications in summer 2015. The study area is located in Tabas city, South Khorasan province (Iran) with longitude 56o 53' and latitude 33o 34'. The main plots consisted of saline-sodic irrigation water (S) at two levels (S1= EC: 2.1 dSm-1, SAR:11.5 and S2= EC: 5.04 dSm-1, SAR: 20.8) and a combination of sub factors including three treatments of silicon salts (SI): (control (Si0), silicon nanoparticles, 10KgSiha-1 (NSi) and ordinary silicon (by using sodium silicate salt) 10KgSiha-1 (Si)) and three levels of mycorrhiza and Humic acid (MH): (control (MH0), inoculation with Glomus mosseae mycorrhizal fungi (M) and humic acid 10Kgha-1 (H)) as The factorial was placed in the main plots. Results and discussion The results showed that increasing salinity-sodicity of irrigation water decreased grain yield, straw yield, number of panicles per square meter and plant height and its effect on 1000 seed weight and grain number per spike were not significant. Increasing salinity-sodicity of irrigation water decreased the grain yield by reducing the number of panicles per square meter, reduction of the straw yield due to its negative impact in plant height. The application of silicon nanoparticles treatment increased the grain yield compared to non-silicon treatment, but ordinary silicon (sodium silicate) had no effect. Mycorrhizal inoculation increased grain yield, straw yield and panicle per square meter and application of humic acid also increased grain yield, number of panicles per square meter. Mean grain yield at S1 level increased with the use of humic acid and mycorrhiza and in S2 level, mean grain yield increased only with the use of humic acid. Saline-Sodic irrigation water reduced the concentrations of nitrogen, phosphorus, potassium and K/Na ratio, and increased sodium concentration in millet. Application of silicon had no significant effect on nitrogen, phosphorus, potassium, sodium and K/Na ratio in the plant, but mycorrhiza and humic acid increased plant phosphorus and K/Na ratio and decreased sodium content of the plant. ConclusionsAccording to our results, it can be concluded that the use of silicon nanoparticles in comparison with ordinary silicon (sodium silicate) could increase the yield of millet. Also the application of humic acid or mycorrhiza can be improved the yield of millet by increasing the amount of phosphorus and K/Na ratio and decreasing sodium content in millet and thus the enhancement of resistance of the plant and the reduction of the effects of salinity-sodicity of water irrigation, and in this regard, the effect of humic acid was much superior to mycorrhiza impact.