Silicon最新文献

Enormous advantages can be brought by using silicon as a substrate for III-V photonic integrated circuit quantum dot (QD) lasers, such as a low cost, high bandwidth transmission data, on-chip light sources, etc. However, several difficulties arise when III-V QD lasers are grown directly on Si-substrate, mainly due to high lattice mismatching between the III-V components and the silicon wafer. In fact, a highly thermal expansion coefficient difference, threading dislocation densities (TDDs), and antiphase boundaries (APBs) are the crucial obstacles for developing a high-performance semiconductor laser on Si. In this regard, many approaches and strategies have been devoted to tolerantly grow III-V on Si. In this review, the history of QD laser diodes directly grown on Si-substrate is demonstrated. The benefits and the problems of III-V semiconductor materials epitaxially grown on Si are discussed. The recent progress in QD lasers grown in silicon is reviewed, focusing on InAs-QD lasers in terms of threshold current density, output optical power, emission wavelengths, and operation temperatures. The future of QD lasers monolithically grown on Si-substrate and their application are also discussed in this review.

We have prepared composite nanomaterials based on opal matrices with silica particles with a diameter of 300 nm and compounds of metals of group 10 of the periodic table (Pt and Pd). The first time dichlorodiamminepalladium and its water-ammonia solutions as a source of palladium for filling opal matrices are used. In addition, experiments were carried out on the introduction of platinum and palladium into a silica matrix with nano-sized pores using amino groups. Conditions have been found for obtaining materials with various forms of metal incorporation, both in the form of isolated particles in the voids of the opal matrix, and in the form of a continuous coating of the surface of a silica particle. A study of the electromagnetic properties of these samples showed a significant change in impedance and dielectric constant compared to the original opal matrix. The resulting composite nanomaterials, such as metal-filled inverse opal, can find wide application in various fields of optics, electronics, and catalysis.

In this work, tungsten oxide (WO₃) particles (in micro and nanoscales) have been mixed with silicon epoxy resin to create a novel composite to enhance the radiation attenuation properties of an epoxy resin shield. Six epoxy resin samples were created using various WO₃ micro/nanoparticles concentrations. Several radioactive sources with varying energies were employed along with a high-purity germanium detector to evaluate the prepared samples' shielding capabilities. The linear attenuation coefficients (LACs) were measured experimentally using the narrow beam method. Based on the experimentally obtained values of LACs, other radiation shielding parameters, including half value length (HVL), tenth value layer (TVL), radiation shielding efficiency (RSE), and mean free path (MFP), were computed. The EW-20m30n sample (50% epoxy + 20% micro WO₃ + 30% nano WO₃) had the lowest MFP, HVL, and TVL at any given energy. Thus, in terms of material thickness, the EW-20m30n sample offers the best shielding characteristics. Furthermore, because of its superior density, the almost even mixture of nanoparticles and microparticles in the EW-20m30n sample produces a RSE of ≅ 100% in the low energy zone. Conversely, it was found that the samples' ability to protect decreased as the energy increased. Calculating HVL, TVL, and MFP revealed a high energy dependence that grew as the incident photon energy rose. On the other hand, for 50% micro WO₃ and 50% epoxy, the EW-50m sample had the least ideal shielding characteristics. Categorically, our study has demonstrated that adding WO₃ micro/nanoparticles to epoxy resin polymer has improved the polymer's radiation shielding properties.

Zeolite Faujasite Y was synthesized, ion-exchanged with NH₄⁺, and calcined to provide the protonated H-Y form. Subsequent post-synthesis alterations included dealumination with oxalic acid for varied durations (1 and 2 h), resulting in samples labeled as H-Y/1h and H-Y/2h. Characterization techniques demonstrated the persistence of the zeolite Y structure despite minor crystallinity loss, particularly in H-Y/2h. Textural improvements were seen following protonation and dealumination. NH₃-TPD analysis revealed that acid treatment resulted in considerable aluminum removal from the zeolite structure, increasing the concentration of strong acid sites in the treated samples. Methanol adsorption kinetics at 25 °C exhibited pseudo-second-order behavior due to its small kinetic diameter and low polarity, which facilitated diffusivity in micro- and hierarchical pores. At 35 °C, Na-Y, H-Y, and H-Y/1h samples exhibited second-order kinetics, indicating favorable methanol adsorption dynamics within zeolite pores. DTG study of methanol adsorption showed that hierarchical porosity creation efficiently suppressed coke formation, hence conserving catalytic activity, as seen in H-Y/2h at high temperatures. These findings highlight the crucial significance of post-synthesis treatments in increasing methanol adsorption and imparting coke resistance to zeolite-Y catalysts.

The thermodynamic data for the low-temperature hydrogenation of silicon tetrachloride (STC) were calculated using density functional theory with W1 theory. Based on these calculations, the equilibrium concentration distribution was determined for different temperatures (373.15–1173.15 K), pressures (1–40 atm), and composition ratios of H₂/STC (0.2–4) using the principle of chemical equilibrium. It was observed that the conversion rate and selectivity rate decreased with increasing temperature, while they increased with increasing pressure and composition ratio of H₂/STC. The selectivity rate could only be significantly altered under extreme conditions. When the temperature and pressure were fixed, the yield reached its theoretical maximum when the composition ratio of H₂/STC was between 0.5 and 1. Furthermore, sensitivity analysis results revealed that pressure and composition were the primary parameters influencing conversion, with temperature having only about one-tenth of their impact on the conversion rate. Ultimately, the experimental results were in good agreement with the calculated results, confirming the acceptability of the thermodynamic analysis.

A nanosecond-pulsed laser with a wavelength of 1064 nm was used to irradiate silicon, and the concentration of water mist and smoke was characterized through light transmission. The drift and scattering effects of the laser propagation atmosphere (water mist and smog environment) on the laser and the influence of different ambient atmospheres on the effect of the laser irradiation on silicon were studied. Research has shown that when a laser passes through a water mist environment, as the laser transmission ratio increases, the diameter of the exit spot increases, and the diameter of the damage induced to single-crystal silicon increases approximately linearly. The erosion damage is enhanced, and a mixture of heat and stress damage occurs. Smoke is a simulated haze environment, and the attenuation effect of the aerosol content on the laser in a smoke environment depends on the particle size and concentration. When the laser transmission ratio is the same, the diameter of the particles is small, and the corresponding particulate matter concentration is large. The smaller the particle size, the larger the particle concentration corresponding to a different laser transmission ratio. When the laser energy of the target is the same, the shape and size of the export laser change as the laser passes through fog; furthermore, the damage shape is no longer circular, but it is rather stretched and deformed along a specific direction. This study can provide a reference for laser processing, far-field laser applications, and atmospheric optics.

This study highlights the influence of replacing Na₂O with NaF on the photon interaction parameters of 40SiO₂-20Al₂O₃-(10 + x)Na₂O-(20-x)NaF-10YF₃ (for x = 0, 2, 5, 7, 10). The mass attenuation coefficients (MACs) and mass energy absorption coefficients (MEACs) of the glass ceramics were computed for gamma-rays in the 15 keV-15MeV energy range using the NIST-XCOM database. The MAC and MAEC vary within the ranges of 0.0224–10.1508 cm²/g and 0.0156–6.4896 cm²/g for Si-ANNYF1, 0.0223–9.8821 cm²/g and 0.0164–6.3694 cm²/g for Si-ANNYF2, 0.0222–9.6097 cm²/g and 0.0163–6.2508 cm²/g for Si-ANNYF3, 0.0221–9.3724 cm²/g and 0.0163–5.5476 cm²/g for Si-ANNYF4, and 0.0220–9.1310 cm²/g and 0.0162–5.4131 cm²/g for Si-ANNYF5. The analysis of other estimated parameters showed that increasing the relative weight proportion of NaF₂ relative to Na₂O influenced the ability of the glass ceramics to interact and absorb energy from incident gamma photons. Adding more NaF made the glass ceramics better at confining photons in both the narrow and broad beams scenarios. The Si-ANNYFx glass ceramics are recommended for gamma shielding applications in nuclear industries.

This work wants to investigate the potential of Cu-Si₅₂, Cu-C₅₂, Cu-Al₂₆N₂₆, Cu-doped nanotubes (6, 0) to adsorb and deliver the Favipiravir as COVID-19 drug by DSD-PBEPBE-D3/aug-cc-pVDZ method. This work aims to propose the suitable materials for drug delivery of Favipiravir as COVID-19 drug. Results indicated that the Cu adoption can be increased the stability of Si₅₂, C₅₂, Al₂₆N₂₆, SiNT (6, 0), CNT (6, 0) and AlNNT (6, 0), significantly. The ΔG_adsorption of complexes of Favipiravir with Cu-Si₅₂, Cu-C₅₂, Cu-Al₂₆N₂₆, Cu-doped nanotubes (6, 0) are -3.14, -3.25, -3.40, -3.89, -4.03 and -4.13 eV, respectively. The recovery time (τ) values of complexes of Favipiravir with Cu-Si₅₂, Cu-C₅₂, Cu-Al₂₆N₂₆, Cu-doped nanotubes (6, 0) in gas phase are 50.0, 51.8, 55.0, 56.3, 58.3 and 63.0 s. The Cu-AlNNT (6, 0) and Cu-Al₂₆N₂₆ have higher recovery time (τ) than Cu-Si₅₂, Cu-C₅₂, Cu-doped nanotubes (6, 0). Results shown that the Cu-Si₅₂, Cu-C₅₂, Cu-Al₂₆N₂₆, Cu-doped nanotubes (6, 0) have higher capacitates and abilities to deliver and transfer of the Favipiravir than other nanostructures in previous works. Finally, the Cu-AlNNT (6, 0) and Cu-CNT (6, 0) are proposed as acceptable structures to deliver and transfer of Favipiravir as drug of Coronavirus disease.

Here, the capacities of S-C₄₈, S-C-nanotube, S-B₂₄N₂₄ and S-BN-nanotube in Mg-ion and Na-ion batteries are investigated. The E_cohesive of Si₄₈, C₄₈, S-C₄₈, B₂₄N₂₄, S-B₂₄N₂₄, CNT(7, 0), S-CNT(7, 0), BNNT(7, 0) and S-BNNT(7, 0) are -5.86, -5.98, -6.24, -6.35, -6.47, -6.60, -6.88 and -7.01 eV in gas phase. The electrochemical parameters of Si₄₈, C₄₈, C-nanotube, B₂₄N₂₄, BN-nanotube, S-C₄₈, S-C-nanotube, S-B₂₄N₂₄ and S-BN-nanotube in batteries are calculated. The V_cell and C_theory of Si₄₈, C₄₈, CNT, B₂₄N₂₄, BNNT, S-C₄₈, S-CNT, S-B₂₄N₂₄ and S-BNNT in Mg-ion batteries are higher than Na-ion batteries. Results demonstrated that the V_cell and C_theory of C₄₈, S-C₄₈, B₂₄N₂₄, S-B₂₄N₂₄, CNT(7, 0), S-CNT(7, 0), BNNT(7, 0) and S-BNNT(7, 0) in batteries are higher than corresponding values of Si-nanotubes, C-nanocages and Si-nanocages, C-nanotubes, C-nanocages and BN-nanocages and BN-nanotubes. Results indicated that the S-C₄₈, S-B₂₄N₂₄, S-CNT(7, 0) and S-BNNT(7, 0) have acceptable capacities in metal-ion batteries. Finally, the S-Si₄₈, S-BNNT(7, 0) and S-CNT(7, 0) are proposed to utilize in batteries.

The optoelectronic properties of doped BaSiO₃-based semiconductors play a very significant role in modern optoelectronic devices. We provide key insights into their versatility and potential in developing technologies by analyzing their structural, electrical, elastic, optical and thermoelectric properties using Wien2k software and GGA + U method. The aim of this research is to enhance the usability of complex resources for new and practical applications. We begin our analysis by applying Birch-Murnaghan fitting to study the structural features of BaSiO₃ crystals doped with Er³⁺ and Yb^3+. This study explores the structural, electronic, and thermoelectric enhancements of BaSiO₃ semiconductors doped with Er³⁺ and Yb³⁺. Through detailed analysis, we have identified critical modifications in the lattice parameters and crystal structures, confirming an improvement in general stability and functionality. Notably, doping has effectively reduced the energy band gap from 1.12 eV in undoped BaSiO₃ to a metallic state, optimizing the material for optoelectronic applications. The introduction of Er³⁺ significantly increases optical absorption and reduces the optical band gap, while Yb³⁺ extends absorption into the near-infrared spectrum. Both dopants particularly enhance the thermoelectric properties of BaSiO₃, with a marked increase in the power factor. Additionally, these doped materials show substantial absorption of ultraviolet photons and moderate reflection across infrared and visible spectra. The findings from this research position Er³⁺ and Yb³⁺ doped BaSiO₃ as promising materials for advanced thermoelectric and optoelectronic applications, suggesting potential for significant technological advancements in energy-efficient devices.