Silicon最新文献

Ba_1.98Dy_0.02SiO₄ nanoceramic samples were synthesized using the most versatile sol–gel and citrate sol–gel techniques. The properties of Ba_1.98Dy_0.02SiO₄ nanoceramics were perceived by XRD pattern, IR spectra, UV–Vis-DR Spectra, FESEM, etc. XRD confirmed the phase purity and homogeneity of the samples. Rietveld refinement methodology was employed to authenticate the prepared samples' structural parameters and crystal structure. FTIR analysis provides the IR vibrations consistent with bonding among the atoms and molecules. Compared to IR, high-frequency Raman modes attributed to SiO₄ units are shifted. FESEM micrographs revealed the formation of spherical shape nanoparticles and nanorods. EDAX spectra governed the elemental composition of prepared samples, further confirmed via XPS scan. Diffuse reflectance examined optical modifications and band structure of the nanoceramics. The band gap of the proposed samples was intended to use the best relationship between the Kubelka Munk function and reflectance data. The comparative results showed that the citric acid-assisted Ba_1.98Dy_0.02SiO₄ sample has better structural and optical characteristics with nanorod morphology functional in device fabrication. At the same time, the sample prepared by traditional sol–gel has spherical nanopowders suitable for display devices. The 0-dim and 1-dim morphology of the samples were ascribed to the significant differences in the synthesis conditions.

In this work, we studied the electrochemical behaviour of silicon ions in NaCl-KCl-KF molten salts containing K₂SiF₆ at 1003 K. Electrochemical techniques such as cyclic voltammetry, chronopotentiometry and chronoamperometry were used to study the kinetics of Si deposition on molybdenum working electrode. The diffusion coefficient and nucleation mode of silicon ions were investigated. The nucleation mode of Si ions was determined to be instantaneous nucleation by chronoamperometry. The diffusion coefficient of Si ions is 0.32 × 10^–5 cm².s⁻¹ and 1.21 × 10^–5 cm².s⁻¹ from cyclic voltammetry and chronopotentiometry, respectively. Before Si film formation, MoSi₂ layer is formed on the Mo electrode. Electrolysis was performed in potentiostatic and galvanostatic modes. SEM, EDS and XRD analysis was performed on cathode products. At low cathode current densities, only MoSi₂ is formed, whereas MoSi₂ layer formation followed by thick Si film deposition takes place at high current densities.

In chemical graph theory, topological indices are numerical quantities associated with the structure of molecular compounds. These indices are utilized in the construction of quantitative structure-property relationships (QSPR) and quantitative structure-activity relationships (QSAR) analysis and quantify the different features of the molecular topology. M-polynomial gives a handy method for managing complex computations involving various indices and offers a consistent methodology to derive multiple degree-based topological indices. Graph entropy measures are employed to measure the structural information content, disorder and complexity of a graph. In this article, we examine the geometric-quadratic (GQ) and quadratic-geometric (QG) indices for silicon carbide networks, namely (text {Si}_{2}text {C}_{3} textit{-I}[p,q]), (text {Si}_{2}text {C}_{3} textit{-II}[p,q]) and (text {Si}_{2}text {C}_{3} textit{-III}[p,q]) with the help of their respective M-polynomials. Next, we propose the idea of the GQ-QG indices-based entropy measure and compute their expressions for the above-said networks. Furthermore, the graphical representation and numerical computation of the GQ-QG indices and associated entropy measures are performed to assess their behavior. These indices and entropy measures may be helpful in predicting the physico-chemical properties and understanding the structural behavior of the considered silicon carbide networks.

Hydroxyl-terminated polydiphenyl-methylphenyl siloxane (PDPMPS-OH) was synthesized by a non-hydrolysis sol–gel condensation method, using diphenylsilanediol (DPDS) and methylphenyl dimethoxysilane (MPDMS) as the raw materials. Subsequently, the synthesized PDPMPS-OH was reacted with divinyltetramethyldisiloxane (MM^vi) to produce a vinyl-terminated polydiphenyl-methylphenyl siloxane (PDPMPS-Vi) with a high refractive index of 1.580 and a long chain linear structure. The optical adhesive product (CSOA) cured by PDPMPS-Vi and a hydrogen-containing silicone resin, exhibits excellent optical performance, high reliability, and significantly enhanced tensile strength (up to 384 kPa), hardness (up to 48 O), and elongation at break (up to 237.9%), as well as a refractive index of up to 1.575. This adhesive demonstrates remarkable performance as an optical component adhesive.

The continuous Czochralski (CCz) method is a low-cost and high-efficiency method for the production of monocrystalline silicon. The inner crucible is an extremely important component in the CCz method. In this work, the crystal silicon rod production process with a diameter of 215.00 mm is simulated to study how the inner crucible radius influences the thermal field of the melt and the melt-crystal (m-c) interface shape with the outer crucible size remaining constant. Additionally, the effects of varying the inner crucible radius on the Von Mises stress within the crystal and the distribution of oxygen impurities in the melt are also examined. The results show that when the radius of the outer crucible is fixed, the required heater power increases slightly with the increase of the inner crucible radius. However, the convexity and deflection of the m-c interface, the Von Mises stress inside the crystal, and the oxygen impurities content at the crystal growth interface decrease with the increase of the inner crucible radius. Therefore, the larger inner crucible size is favorable for silicon crystal production using CCz. The results of this work can improve the production efficiency and quality of the silicon crystal.

For nanobeam resonators, it is of the utmost importance to have a solid understanding of how to tune the energy damping and thermal quality factor. The periods of thermal and mechanical relaxation are quite important when it comes to adjusting energy damping. Within the scope of this study, the novelty of this work is constructing an analytical thermal model to investigate the effects of the static pre-stress, as well as the thermal and mechanical relaxation periods, on a viscothermoelastic silicon nano resonator in the context of a hyperbolic two-temperature dual-phase-lag heat conduction model. Several factors, including the length scale, mechanical relaxation time, thermal relaxation times, static-pre-stress, and isothermal frequency, have been investigated concerning the thermal quality factor. It is possible to alter the length-scale parameters, as well as the static-pre-stress, thermal, and mechanical relaxation times, to achieve a significant increase in the thermal quality factor. The isothermal frequency is another factor that has a major impact on the thermal quality factor of the viscothermoelastic silicon nano resonator.

With the rapid development of the photovoltaic industry, the demand for crystalline silicon has significantly increased. Water-based waste slurry generated from silicon wafer cutting with diamond wire is a byproduct, presenting considerable potential for reutilization. However, the presence of moisture can lead to silicon oxidation and SiO₂ layer formation on the surface, hindering the recovery of high-purity silicon. In this study, the first-principles was employed for investigating the adsorption property of H₂O on Si (111) and Si (100) surfaces, based on density functional theory. The results indicate that H₂O can spontaneously adsorb on both the (111) and (100) surfaces of Silicon, and the affinity of H₂O for the Si (111) surface being stronger than the Si (100) surface. Furthermore, Mulliken charge calculations and differential electron density analysis confirm that charge transfer of H, O and Si atoms occurs during the adsorption process between Si and H₂O. The Si–O bonds formed on the Si (111) surface exhibit greater covalency compared to the Si (100) surface, suggesting that the Si (111) face is more susceptible to oxidation than the Si (100) face. This study provided theoretical insight into the adsorption of silicon in water at the atomic level, which is significant for deepening the understanding of silicon's oxidation mechanisms.

The ability to resist plastic deformation of the surface is extremely important for polycarbonates (PC), which are widely used in various industrial applications. This work is dedicated to the study of the possibility of using atmospheric pressure (AP) plasma enhanced chemical vapour deposition (PECVD) in dielectric barrier discharge (DBD) for the deposition of silica-like films as a method of strengthening of the PC surfaces. This is the first systematic study of the effect of the main process parameters on microhardness, scratch resistance and abrasion resistance of protective silica-like layers deposited on PC by this method using hexamethyldisiloxane (HMDSO) as a silicon-containing reagent. Also the numerical evaluation of the above mentioned properties of the coatings has been carried out. It has been found that the surface microhardness is most dependent on the amount of oxygen added to the gas mixture, the abrasion resistance is most affected by the electrical power absorbed in the discharge, and the scratch resistance is highly influenced by all process parameters. It has been shown experimentally that the microhardness of such silica-like films can reach 10 GPa (close to the typical value for quartz) and the near-surface microhardness of PC can be increased almost two times, scratch resistance increases by 8 points, and rolling abrasion resistance increases from 56 to 95% when the coating with the thickness of several dozen nm was deposited.

Improving the yield of different safflower cultivars using silicon and nickel foliar application in a saline soil condition was the hypothesis proposed in this research. For this purpose, a factorial experiment was conducted in the form of a randomized complete block design in Haji Abad, Iran, in 2019 and 2020. The first factor included four cultivars of safflower including Sofeh, Isfahan, Padideh and Golmehr, and the second factor was seven foliar spraying treatments, consisted of control, nickel with concentrations of 100, 200, and 300 mg L⁻¹ and silicon with concentrations of 100, 150, and 200 mg L⁻¹. Results showed that silicon foliar application of 150 and 200 mg L⁻¹ increased potassium content by 10 and 16%, respectively, in compared to the control. Nickel foliar spraying of 300 mg L⁻¹ caused an increase in leaf ion leakage and a decrease in photosynthetic pigments. On the other hand, silicon foliar application of 200 mg L⁻¹ increased the total leaf chlorophyll content by 12 and 18% in Sofeh and Isfahan cultivars, respectively. Compared to the control, silicon with the concentration of 200 mg L⁻¹ caused a 10 and 13% decrease in soluble carbohydrate and proline, respectively. In Isfahan and Padideh cultivars, silicon foliar spraying of 150 and 200 mg L⁻¹ increased the seed yield by 21 and 15% compared to the control. The results of this research showed a positive effect of silicon foliar spraying especially with concentrations of 150 and 200 mg L⁻¹ on improving seed yield and oil percentage in different safflower cultivars under salt stress.

The current study goals to create of PS-SiC-Al₂O₃ multifunctional nanocomposites films as a promising nanomaterials to exploit in futuristic nanoelectronics and optical fields. By comparing with other nanocomposites films, the PS-SiC-Al₂O₃ films have high absorption for UV-radiation, flexible, low band gap, and inexpensive. The microstructure and optical characteristics of PS-SiC-Al₂O₃ films were investigated. The microstructure and morphological properties included FTIR and OM. The realized results indicated that the values absorbance for PS-SiC-Al₂O₃ films are high at NIR and UV spectrums. These results build the films of PS-SiC-Al₂O₃ are promising for NIR sensing, UV shielding and optoelectronics approaches. The increment ratio of PS absorbance is 30.9% for λ = 320 nm and SiC-Al₂O₃ content is 2.4 wt.%. The PS band gap is 3.8 eV and its reduced to 3.13 eV with increasing SiC-Al₂O₃ NPs content to 2.4 wt.%.. This performance leads to make the PS-SiC-Al₂O₃ films are welcomed in various optoelectronics and photonics fields. The optical factors: extinction coefficient; absorption coefficient; real and imaginary dielectric constants, refractive index; and optical conductivity of PS were enhanced with increasing SiC-Al₂O₃ NPs content; these results of lead to made the PS-SiC-Al₂O₃ films are suitable for optical fields. Finally, the achieved results confirmed that the PS-SiC-Al₂O₃ films could be as a key for promising nanoelectronics and optical fields.